Metal-organic frameworks (MOFs)are a kind of porous materials by combining metal nodes with organic ligands by strong bonds. Compared with the traditional adsorption materials, MOFs have various advantages, such as adjustable structural, functional diversity, large specific surface area and high porosity. Another unique advantage is that the pores size can be adjusted, and the specific functional groups and active sites can be modified by in situ synthesis or post-modification to obtain the efficient and selective adsorption of different heavy metals and radionuclides from wastewater, which is of great significance to resource recycling and environmental remediation. In this paper, the latest research progresses and corresponding adsorption mechanisms for the adsorption of heavy metals (As, Cr, Hg, etc.)and radionuclides (U, Tc, etc.)are described in detail. And the methods of improving the adsorption of MOFs are summarized. Furthermore, the challenges and problems of MOFs as the adsorbents of heavy metals and radionuclides are proposed.

With the innovation inmaterial science and technology, many new particulate materials have emerged, including particularly nanoparticles (NPs), microplastics (MPs) and biochars (BCs). The unique physical and chemical properties of these materials allow them to be applied in a variety of fields, such as biomedicine, packaging and pollution control. To date, the potential risks of these emerging materials on human health have not yet been fully understood during the application process. Although their cytotoxicity effects and reaction mechanisms have gradually become research hotspots worldwide, few efforts have been put on comparing the health risks of these new particulate materials at pre-sent. The unique properties of these materials, such as small size, high charge density and complex dissolved substances, could not only affect their environmental behaviors, but largely affect their toxic mechanisms and effects on animals, plants and microbial cells. Therefore, the objective of the present article is to compare and discuss how the physical properties of NPs, MPs, and BCs, including particle size, surface charge and dissolution rate, influence their corresponding environmental behaviors in adsorption and aggregation. Subsequently, the toxicity mechanisms (e.g. particle size, surface charge and dissolved substances) of these particular materials on animals, plants and microbial cells were also explored and summarized in the present study. The potential research gaps were analyzed, based on which the suggestions for improvement were present to provide fundamental knowledge in carrying out the risk assessment of emerging materials with similar properties.

In recent years, microneedles have received a lot of attention from researchers because of its advantages of being painless and minimally invasive, safe and efficient. Microneedles have been widely used in the fields of transdermal drug delivery, medical aesthetics and biological diagnosis. However, traditional microneedles, especially those prepared directly from polymer materials, generally have problems such as low mechanical strength, single drug release mode, poor biological sensing performance and simple functions. The clever combination of nanotechnology and microneedles can effectively improve the above problems, due to the unique nano-size, mechanical strength and photoelectric effects of nanoparticles. This paper reviews nanoparticles for microneedles, including inorganic nanoparticles (metal, inorganic non-metal), organic nanoparticles (polymer, lipid) and drug nanoparticles (nanocrystalline drugs, virus-like particles), and describes the role of nanoparticles in increasing mechanical property, synergistic improvement of drug release and immune enhancement are introduced. Finally, the urgent problems need to be solved in this field and the future research directions are discussed.

Sensors are convenient, fast and sensitive, and have great potential in various detection fields. Hydroxyapatite(Ca₁₀(PO₄)₆(OH)₂, HAp) is the main inorganic component of the bone and tooth of vertebrate, and has been widely used as biomaterial.In recent years, it has been widely used for sensing materials and has shown great potential, due to its unique three-dimensional network structure, good stability, excellent adsorption capacity, and ion exchange feature.
The performance of pure HAp is limited when used alone due to the constraints of conductivity and mechanical strength. In order to improve its comprehensive performance, researchers mainly try to modify it by ion-doping (Ag⁺, Fe²⁺, Pb²⁺, etc.) or preparing composite materials with other materials, such as graphene, carbon nanotubes, conductive polymers, biological enzymes and so on. Some progress has been made in improving the sensitivity and stability, and reducing the detection limits of HAp. HAp and its composites have better sensing performance for ammonia and alcohol gases than other gases, and can detect lower concentrations of toxic and harmful gases at room temperature. Due to its good ion exchange properties, HAp can detect many heavy metal ions, such as Pb²⁺, Cu²⁺, Hg²⁺, As³⁺, Cd²⁺ and so on, and can be used in the fields of environment protection and medical care. HAp can also be used to detect more than ten kinds of biomass, including uric acid, glucose, L-dopa, etc. If used as a carrier of biological enzymes, it can detect specific substances with excellent selectivity. HAp can also be used as a moisture-sensitive material. Modification by doping metal ions to improve the conductivity is a potential way to improve the humidity sensitivity of HAp. In addition, HAp has also been reported in photo, magnetic and thermal sensing applications.
Firstly, we review the basic microstructure, properties and synthesis methods of HAp briefly. Then we mainly focus on the research progress of HAp and its composite in the fields of gas sensing, ion sensing, biosensing and humidity sensing. Finally, the research direction of HAp as sen-sing materials in the future is prospected.

As a new type of green energy material, metal deuteride has excellent deuterium storage performance, and its importance and widespread application in the energy field have been more and more outstanding. Under the high speed of social and practical applications' development, metal deuteride energy materials will play a more and more important role in the country's energy strategy. The metal deuterides is usually prepared by direct compounding in a high-temperature environment. It is highly susceptible to O₂, CO₂, H₂O, etc in the air atmosphere, especially the high humidity (more than 60%) air atmosphere because of the very active surface chemistry. It can cause changes in the performance of metal deuterides, which may cause safety hazards in severe cases, and the scope of use is limited. At present, a variety of metal deuteride materials such as lithium deuteride, titanium deuteride, zirconium deuteride and cerium deuteride have been prepared successively and have certain applications. This article summarizes the research progress of several common metal deuterides preparation and application according to the cha-racteristics, classification and applications of metal deuterides, summarizes the research status and progress of metal deuterides, and puts forward prospects. The purpose is to summarize data and reference for the research and application of deuterated metals.

The space charge has been a key factor to affect the electrical properties of solid insulation materials. The existence of space charge can cause uneven electric field distribution in polymer, accelerate the aging of insulating materials, and even lead to the breakdown of materials. This paper summarizes the influence factors of space charge accumulation in solid insulation materials, and points out that the accumulation of space charge is closely related to the applied electric field(effects of electric field, electric field type, pre-applied voltage and polarity reversal, etc.), temperature(high temperature, temperature gradient, low temperature), stress, and structure of the dielectrics(such as crosslinking degree, insulation thickness). The suppressed methods to space charge accumulation were summarized from the aspects of electrode materials, surface modification and doping fillers(morphology, size, type and content). The relevant mechanisms of space charge accumulation and suppression are discussed, and the space charge transport mechanism based on trap theory still needs to be further studied.

In recent years, rare earth yttrium has been widely used in various applications, especially in crystalline luminescent materials, due to its excellent physical and chemical properties. And it gradually becomes an important additive in industrial production all over the world. However, China is the world's largest exporter of rare earth yttrium resources, yet the use of rare-earth yttrium processing in industrial production is still at a low level. How to develop and utilize rare earth yttrium resources has gradually become a huge problem on China's industrialization path. In this paper, we have focused on the current research status of Y/Y₂O₃ in related industries, such as luminescent crystals, metallurgy, superconductivity, biomedicine and other important fields, expecting to provide assistance in the design and development of yttrium resources in China.

Geopolymer cement is a kind of environment-friendly inorganic cementitious materials. It takes metakaolin rich in resources or industrial solid waste with high silicon, aluminum and low calcium as precursors. And it can be mixed with a variety of other solid wastes and chemical agents to adjust the performance, with good controllability. Compared with Portland cement, its mechanical properties, working performance and durability have great advantages. It is one of the best materials to replace Portland cement in the future. This paper reviewed the research progress of geopolymer cement at home and abroad in the aspects of precursor materials, reaction mechanism, mechanical properties, working performance and durability, and discussed the current problems and future development prospects of geopolymer cement.

Continuous basalt fibers made by drawing raw basalt ore have been recognized as a kind of high-performance and environmental friendly inorganic mineral fiber, which has a wide range of applications and is of great significance in both industrial development and national defense construction. By reviewing the development of preparation technology for continuous basalt fibers, this paper introduces the crucible and tank kiln method, especially the current common tank kiln production process, as well as the three main influencing factors of tank kiln process including ore raw materials, key equipment and wetting agent. Moreover, this paper briefly introduced the different effects of various elements in basalt fiber on the its properties, and compares the properties and parameters of basalt fiber with other high-performance fibers. It is considered that continuous basalt fiber has excellent comprehensive properties. Combined with the application forms of continuous basalt fiber, its applications are summarized, including the application of geotechnical reinforcement of basalt fiber wire, the application of temperature resistance and heat insulation of wire processed into a variety of fabrics, the application of rock wool and scale, the application of basic profile (composite reinforcement, composite plate, composite pipeline, etc.), and the application of composite materials in many industrial fields or special fields. On the basis of the above, this paper analyzed and prospected the development prospect, crucial fields of application, impact factors of production, preparation technology and industrial expansion of continuous basalt fibers, so that to motivate their engineering level and industrial development in China.

Thermoelectric materials that convert electric energy and thermal energy are applied as functional materials in waste heat recovery and semiconductor refrigeration. Research on conventional thermoelectric materials has reached maturity; further development of such materials is hampered by the high cost of raw materials and low thermoelectric conversion efficiency. To overcome these limitations, Mg₃(Sb, Bi)₂Zintl phases have attracted extensive attention since their discovery and have been widely applied as thermoelectric materials because of their low cost and intrinsic low thermal conductivity. In addition, N-type Mg₃(Sb, Bi)₂-based conduction materials, having a high Seebeck coefficient owing to high energy band degeneracy, are hypothesized to be more effective than conventional medium- and low-temperature thermoelectric materials. However, the application of Mg₃(Sb, Bi)₂-based thermoelectric materials is limited because of the low carrier concentration caused by the large bandgap and the low thermal stability due to Mg vacancies. In addition to the maintenance of initial low thermal conductivity of such materials, researchers have continually tried to improve the electrical transport performance and thermal stability by employing different preparation processes and by conducting component and structure optimization. At present, the maximum ZT value of Mg₃(Sb, Bi)₂-based thermoelectric materials is above 1.8, and the conversion efficiency of the Mg₃(Sb, Bi)₂-based thermoelectric devices has been comparable to that of conventional low-temperature thermoelectric materials. This paper summarizes the physical properties and preparation methods of Mg₃(Sb, Bi)₂-based thermoelectric materials. The research progress on different optimization methods to prepare Mg₃(Sb, Bi)₂-based thermoelectric materials is discussed in detail, and possible future developments of the materials are presented.

As a new semiconductor material, perovskite (ABY₃) has unique crystal structure, adjustable band gap, high carrier mobility and excellent chemical stability, thermal stability and catalytic performance. It shows great development potential in the fields of solar cells, photoelectric detection, industrial catalysis, gas sensing and so on. Based on the analysis of its crystal structure and sensing mechanism, this paper summarizes the research progress of perovskite in the field of gas sensing in recent years, systematically discusses various factors affecting the sensing response, and summarizes the strategies to improve the gas sensing properties of materials. Finally, the challenges of perovskite materials in the field of gas sensing are summarized, and their future development is prospected. Perovskite materials with high efficiency, stability, environmental protection and low energy consumption are the focus of future research, and self-powered sensing chip, multi signal coupling sensing and miniaturized intelligent integration will provide a broader development space for its application.

As a common building material, asphalt is widely used in pavements, waterproofing, and other construction applications. Asphalt pavements are flat and seamless, making it comfortable for driving and convenient to maintain. As such, it is a popular preference among the various road pavement types. However, asphalt materials typically release volatile organic compounds (VOCs) to the surrounding environment during construction. These compounds seriously affect air quality and endanger human health. Further research on VOC release characteristics and suppression strategies with respect to asphalt materials is one of the important steps toward adopting and developing green transportation. At pre-sent, research has been conducted regarding the aspects of characterization methods, component characteristics, influencing factors, and suppression strategies. The research results show that there is no universal standard for characterizing VOCs emitted by asphalt, making it difficult to compare and analyze results. Furthermore, the composition characteristics and influencing factors of VOCs are not related to the internal properties of asphalt materials. Moreover, the development of suppression lacks theoretical guidance, which leads to low suppression efficiency and poor performance of asphalt. Accordingly, this paper summarizes the status of research conducted domestically and abroad on VOCs release characteristics and suppression strategies with regard to asphalt materials. The characterization methods, component characteristics, influencing factors, and suppression strategies are introduced. The existing problems and prospects future research are also analyzed.

H₂O₂ shows strong oxidizing properties and is widely used in papermaking, sewage treatment, and disinfection. The global demand for H₂O₂ is increasing, but the anthraquinone method for production of H₂O₂ is complicated, high cost, and low efficient. The direct hydrogen-oxygen synthesis is great safety risks. Therefore, electrocatalytic oxygen reduction reaction, as an emerging, green and safe in-situ synthesis of H₂O₂, has attracted widespread attention in recent years.
Oxygen reduction reaction (ORR) is a multi-electron reaction, the intermediates are complex and difficult to measure, which makes it hard to study the mechanism. There are two competing reaction paths in ORR, two electron paths get H₂O₂, and four electron paths generate H₂O. The efficiency of two-electron oxygen reduction reaction (2e^- ORR) depends on the activity, selectivity, and stability of catalyst.
At present, the noble metal catalysts, such as Au and Pd, show good performance in 2e^- ORR to produce H₂O₂, but they are expensive and rare. Therefore, three strategies have been proposed. (Ⅰ) Decreasing the loading of noble metal. Integrating the inert metals with the active me-tals to obtain many high-performance alloy materials, such as Pt-Hg. (Ⅱ) Developing noble metal-free catalysts. The defects, surface oxygenic functional groups (C=O, C-O), heteroatom doping (N-, S-) and transition metal doping (Co, Fe) in carbon-based catalysts can all improve the selectivity and catalytic activity towards H₂O₂. (Ⅲ) Developing non-noble metal composite catalysts. Non-noble metal composite catalysts (such as MnO₂/C, CoS₂/C) can promote electron transfer and improve H₂O₂ selectivity.
Herein, the mechanism and test methods of 2e^- ORR are systematically introduced. The catalysts included noble metal-based catalysts, carbon-based catalysts, and non-noble metal composite catalysts in 2e^- ORR for generation of H₂O₂ in the recent years are summarized. The outlook of future research directions of electrochemical generation of hydrogen peroxide is also suggested.

Aseries of V-Mo/TiO₂ catalysts were prepared by impregnation method. The effects of vanadium content, molybdenum content and elemental (Ce, Co, La, Sn) doping on the denitrification activity of the catalyst were investigated. The physicochemical properties and structure of the catalyst were characterized by XRD, BET, H₂-TPR, NH₃-TPD and XPS. The results show that the optimum content of vanadium was 3% and the optimum content of molybdenum was 6%. When Ce, La, Co and Sn were doped into 3%V₂O₅-6%MoO₃/TiO₂, the denitration efficiency of the catalyst was obviously improved. Among them, 3%V₂O₅-6%MoO₃-1%SnO₂/TiO₂ catalyst showed the best denitrification activity and good denitration stability at 180 ℃. After introducing 10vol% H₂O and 0.03vol% SO₂, it exhibited good resistance to SO₂/H₂O. This is mainly because the introduced metal element exists in the form of oxide or vanadate, and has a strong interaction with the active component vanadium species, inhibiting the growth of TiO₂ crystal grains, and plays a role in refining the particle size of TiO₂. A weakly acidic site on the surface of the catalyst is added. At the same time, the number of surface active oxygen and reduced V⁴⁺ and Mo⁴⁺ species has been greatly improved, which enhances the degree of reduction of the catalyst and facilitates the catalytic reduction reaction.

Carbon fiber reinforced silicon carbide (C/SiC) ceramic matrix composites have comprehensive properties such as low density, high strength, high temperature resistance and wear resistance, and have become one of the important thermal structural material systems. At present, it has been successfully applied to aero-engine thermal structural components, aircraft thermal protection systems, braking systems and nuclear structural components. In this paper, the research progress in preparation and application of C/SiC ceramic matrix composites is reviewed. A series of representative preparation methods of C/SiC composites are introduced, with emphasis on the hybridization process combining various preparation methods. The applications of C/SiC composites in the fields of aerospace thermal structure and thermal protection, brake materials and space camera structures are summarized. A more excellent hybrid preparation process and a new composite material system for different application requirements are prospected. The paper is expected to provide a reference for further research on C/SiC ceramic matrix composites in the future.

Metal rhenium has the physical properties of high hardness, high mechanical strength, good plasticity and good mechanical stability as well as excellent catalytic activity and corrosion resistance chemical properties,so it has important application value and broad application prospect in the fields of superalloy and petrochemical industry. However, reserves of rhenium in nature are very small, and the abundance of rhenium in the crust is about 6.57×10^-10.Rhenium resources are relatively scarce in China, and there are no rhenium deposits available for industrial exploitation. Most of these rhenium exist in the form of associated minerals, mostly distribute in molybdenite and copper-rhenium sulfide. Currently, the proved rhenium ore reserves are only about 237 tons.
With the rapid development of aerospace and petrochemical fields, the demand for rhenium resources is increasing.About 80% of rhenium in China is used in the field of superalloys, mainly used to make turbine engine blades of aerospace and aviation, and 20% of rhenium is used as catalysts for catalytic cracking reforming of petroleum.The alloy waste produced in the manufacturing process accounts for about 70% of the an-nual output.Domestic enterprises paid little attention to the recovery of rhenium secondary resources, and the recovery technology was relatively weak, which led to serious resource waste.The global resource recovery and reuse industry is developing rapidly. Western developed countries attach great importance to the recovery and reuse of rhenium secondary resources.The United States and Germany are the major countries for the recovery of rhenium resources, and the recovery amount of rhenium in superalloy in the United States reached 6 tons in 2014.The reuse of rhe-nium will aggravate the deterioration of energy and resources, so it is of great significance to study the recycling process of rhenium resources in a scientific, economic and environmental way to alleviate the problem of energy shortage in China.
There are mainly two kinds of rhenium wastes produced in industry: one is the rhenium-containing smoke, waste catalysts,superalloys and other solid waste, which can be recovered mainly by means of oxidative acid leaching, high-temperature alkali melting, electrolytic dissolution, etc, and then enriched rhenium through treatment.The second is the rhenium waste liquid produced by smelting concentrate, etc. The recovery methods mainly include ion exchange extraction, activated carbon adsorption, biological adsorption and other recovery processes. The key problem is how to improve the recovery rate of rhenium, reduce the cost and no pollution to the environment.Since rhenium and molybdenum are similar in nature, the biggest challenge for China is how to effectively separate rhenium and molybdenum and extract them in a more efficient, economical and environmentally friendly way to achieve industrialization.
Based on the specific situation of rhenium resources in industrial wastes, this paper summarizes the research progress on the recovery and reuse of rhenium secondary resources, and separately summarizes and introduces the recovery methods of rhenium in rhenium solid waste and rhenium waste liquid.Different process of rhenium secondary resources recovery characteristics and the problems are analyzed, the technology for the future development direction is forecasted, in order to realize the maximum recovery and reuse efficiency of rhenium resources and alleviate the current situation of rhenium metal material supply shortage in China.

Geopolymer concrete, a class of newly emerging green building materials prepared from the readily obtainable industrial solid waste, possess a variety of advantages such as low energy consumption & carbon emission and facile production process, as well as excellent compressive strength, acid and alkali resistance, freezing and thawing performance and carbonation resistance. It has displayed notable application potential, and become one of the most promising alternatives to ordinary Portland cement. This paper renders a retrospection of the domestic and overseas research endeavors, a vivid description for the raw materials, mix design, mechanical property, workability and durability of geopolymer concrete, as well as a critical discussion upon the technological problems confronting this novel and prospective engineering material.

Ballastless track concrete structure is the key position for bearing the dynamic loads induced by high-speed running train.With the continuous effects of periodic dynamic loads,internal damage occurs and service performances of ballastless track structure are decreased,leading to the durability issue of ballastless track and insecurity risk of the running train.According to the service characteristics of ballastless track concrete,high-frequency fatigue loads are the main types of dynamic loads under normal service state,however,impact loads cannot be ignored when the track is irregular.This paper summarizes the characteristics of dynamic loads,and then illustrates the requirements for both fatigue and impact performances of ballastless track concrete.Meanwhile,the applicability and limitations of the dynamic performance evaluation method of ballastless track are further elaborated,aiming to provide certain suggestions and directions for the evaluation of service performances and long service life design of ballastless track.

Molybdenum disulfide (MoS₂) is two-dimensional layered material with natural tunable band-gap. Very recently, MoS₂ have received much attention owing to its unusual properties and hold great potential for optoelectronic and microelectronic application. In this paper, basic structure and properties of MoS₂ are introduced firstly. Then the common fabrication methods of MoS₂ are analyzed. The applications of MoS₂ in electronic and optoelectronic devices and the prospects for future applications are summarized in the end.

In order to optimize the preparation method, deeply cognize the properties and extend the application of porous metallic materials, the present paper reviews the preparation methods, properties and applications of porous metallic materials. Preparation methods mainly include the electrodeposition method, dealloying method, solid-state sintering process and liquid solidification. Based on the sound absorption properties, separation performance, thermal and electrical conductivities and catalytic performance of porous metallic materials, the applications of porous metallic materials in automotive industry, aerospace industry and biomedical fields are introduced. The paper ends with a brief description of the future development trend of porous metallic materials,i.e. compositing,introducing gradient and diversifying porous structures.

In recent years,the application of targeted nanotechnology has achieved good therapeutic effects in cancer treatment, especially the co-delivery of various anti-cancer drugs. Compared with single drug treatment, the combined application of different molecular targeted drugs has a wider treatment domain and effectively reduce adverse effects of drugs. In addition, the combination therapy of anti-cancer agents dependent on the same cell pathway decrease the dosage of each drug and enhance therapeutic effects. The aforementioned methods could reverse multi-drug resistance to a certain extent. However, combined administration is limited due to inconsistent cellular uptake caused by pharmacokinetic differences of different drugs. The therapeutic effects are closely related to the relative concentration of the combined drugs. A certain proportion of drug combinations could produce synergistic effect, while other proportions may be additive effect or antagonistic effect. At present, the nanocarriers, including liposomes, polymer micelles, polymer vesicles, dendrimers, hydrogels and inorganic nanoparticles have been demonstrated to deliver anti-cancer agents in various tumor models. These nanocarriers could improve serum stability, enhance biocompatibility and prolong in vivo circulation time. In the present review, we will highlight the co-delivery principle of anti-cancer drugs, the types of co-delivery carriers, two kinds of liposomes on the CombiPlex^ platform whose clinical trials have been completed, and three kinds of classical co-delivery drug systems that are still in preclinical research, including doxorubicin and paclitaxel co-delivery systems, paclitaxel and cisplatin co-delivery systems, doxorubicin and curcumin co-delivery systems. These emerging strategies promise reference and novel ideas for more combinatorial regimens.

The application market for carbon fiber reinforced resin composite materials (CFRP) is increasing. The wide application and upgrading of CFRP components have brought about the treatment of waste and scrapped products and environmental protection issues. The research on CFRP recycling and reuse technology has caused many manufacturers and the attention of experts and scholars. This article reviews the cha-racteristics, processes and application status of existing CFRP recycling and reuse technologies, analyzes the relationship between the molding process of common CFRP parts and applicable recycling technologies, and discusses the technology, supply, and regulations of CFRP parts recycling technology. Looking forward to the development trend of CFRP recycling technology.

Polycarboxylate superplasticizers (PCE) has become an indispensable component of high-performance or ultra-high performance concrete, owing to its low dosage, high water reducing rate (>40%), significant positive effects on the workability, mechanical and durability properties of concrete. PCE. is usually composed of a backbone containing anionic groups (like carboxyl group, sulfonic acid group and phosphate group) and grafted side chains with neutral charge. The anionic groups are adsorbed on the surface of cement particles, providing the electrosta-tic repulsion forces, while the PEO-grafted side chains extend from the cement particle surface into the pore solution to create steric hindrance forces. The synergistic effects of the two forces break down the flocculated clusters and improve the dispersion of cement paste. Diverse modified PCE with different side chains, grafting density, anchoring functional group and length of backbone show various effects and can be employed by concrete with different demand in performance. However, with the continuous raise in requirements of concrete performance and the decrease in quality of raw materials, the performance of PCE may be more sensitive to the mixture proportion parameters (cement type, w/c, etc.) and production conditions such as operating temperature and mixing time. The incompatibility between PCE with carboxyl and polyethylene oxide (PEO) side chains and cementitious materials is increasingly serious. Besides, with the increasing requirements of ultra-high performance concrete, a series of PCE with performances of shrinkage reduction, low viscosity and high slump retention have emerged as the times require.
PCE can be primarily classified into two categories. One is polyester-type PCE, which made from α-methoxy poly (ethylene glycol) methacrylate ester (MPEG-MA) by aqueous free radical copolymerization or esterification/transesterification reaction. The other is polyether-type PCE, which is synthesize by free radical copolymerization in bulk or in aqueous solution with α-allyl-α-methoxy or α-hydroxy poly (ethylene glycol) (APEG) ether and maleic anhydride as key monomers, or copolymerization via isoprenyl oxy poly (ethylene glycol, acrylic acid, and α-methallyl-α-methoxy or α-hydroxy poly (ethylene glycol) ether. Polycarboxylate superplasticizer (PCE) features low dosage and high water reducing rate. Different functional groups of PCE exhibit different effects, for example, carboxylic groups show retarding effect and water reducibility, sulfonic groups exert dispersing effect, and hydroxyl groups retarding and soaking wetting effects, and polyethoxy groups present flowability retention capability. The water reducing rate and ability of delayed hydration inhibition of ester-PCE are slightly lower than that of ether-PCE. The method of free radical polymerization possesses easy process and mild synthesis conditions, nevertheless, it is difficult to control the synthetic products due to the irreversible reaction.While reversible addition-fragmentation chain transfer (RAFT) polymerization can prepare the block PCE with controlled molecular weight and narrow molecular weight distribution. In this article, the development of synthesis techniques of PCE is comprehensively reviewed from the aspects of raw materials, synthesis conditions, synthesis methods and post-processing. The impacts of these factors on the performance of PCE are discussed in detail. Finally, the development trend of PCE is also proposed.

As an important part of supercapacitors, electrolyte plays a key role in determining the performance of device. This review briefly discusses about the characteristics and the latest research results of the electrolytes including aqueous, organic liquid, ionic liquid, solid/quasi-solid polymer electrolyte and redox system for supercapacitors. The classification and property of solid/quasi-solid polymer electrolytes are focused, and put forward the development of wide potential window, high ionic conductivity, and stable electrochemical properties of ionic liquids and excellent mechanical strengths and comprehensive properties of gel polymer electrolytes are trends in the field of electrolytes for supercapacitors in the future. Finally, the development prospect of electrolytes for supercapacitors is proposed.

In winter construction or concrete engineering with early strength requirements, early strength agent plays an important role in speeding up the construction schedule and improving the quality of concrete, and its content is generally not more than 5% of the mass of cement. At present, the traditional early strength components are unable to meet the requirements of green and high performance concrete. Most of the previous studies about early strength agent are conducted at room temperature, while the research of early strength agent in low temperature environment (especially 5 ℃) is relatively insufficient, and low temperature early strength effect is relatively limited, the mechanism of low temperature early strength is also not clear. With the further development of engineering construction, it is an important research direction to develop low temperature early strength agent which meets the requirements of low temperature early strength and good workability. Based on the classification summary of the performance characteristics, existing problems and action mechanisms of the common early strength components, this paper introduces the research and application of early strength agent in low temperature, and also point out the development direction of low temperature early strength agent.

The second generation bio-diesel has the properties of high octane number, low oxygen content and can blend directly with present diesel. The production and application of the second generation bio-diesel can effectively reduce the usage of limi-ted fossil fuel, and thus improve the quality of environment. The research of catalysts is considered as the most crucial part during production of second generation bio-diesel. This article reviews the category, catalytic reaction pathway and the forefront research of catalysts used in oil hydrotreatment. Noble metal catalysts possess high activity by decarboxylation/decarbonylation pathway, but they are expensive. The reaction pathway of conventional molybdenum catalyst is mainly hydrodeoxygenation. Sulfuration of catalyst is necessary before hydrotreatment, which will lead to serious environmental pollution. New-style molybdenum carbide catalyst and nickel catalyst perform catalytic reaction by hydrodeoxygenation pathway and decarboxylation/decarbonylation pathway, respectively. Zeolite as support improves the yield of isomerization alkane in products. Moreover, the prospect of future research of the catalyst is provided.

The main task for the nuclear shielding design is to block out neutron and γ-ray. Thereby, the radiation shielding materials which combine the shielding ability from neutron and γ-ray are the best candidates. This paper offers an elaborate description of the types, substrate materials and performances of the currently applied neutron and γ-ray combined shielding material, and furthermore, roughly discusses the respective principal problems of these materials. We emphasize the crucial and urgent problem with respect to the mutual exclusion between shielding effectiveness and other performances (e.g. mechanical performance, heat resistant stability, etc.). Finally the review sketches out the prospect of the neutron and γ-ray combined shielding materials, suggesting that the development of structure/function integrated radiation shielding materials is one of the future trends.

As a new composite material preparation technology, in situ synthesis has become a research hotspot in recent years due to its simple operation, low cost, good compatibility with other processes and easy promotion.The adoption of in situ reaction in brazing technology has also been widely studied, and found to be able to effectively solve the problems such as poor forming performance, large residual stress and difficult wetting of base metal during the preparation and use of brazing filler metal. In this paper, the current application of in situ reaction in brazing filler metal synthesis is reviewed. Firstly, the research on in situ fusion of low melting point and high strength brazing filler metal by changing the forming process is introduced, and the common forming processes, such as layered composite, extrusion composite, adding metal powder core and surface plating, are summarized. After that, the research on effective connection of dissimilar materials by using in situ reaction to generate composite filler metal reinforcement phase is introduced, Finally, the existing problems of in situ synthesis of brazing filler metal at the emerging stage are pointed out, and the future research directions are prospected.

Steelmaking is a high-consumption and high-emission industry. With the task of peak carbon dioxide emissions and carbon neutrality advocated by the state being put on the agenda, it is urgent to develop a low-carbon economy in the steel industry with high carbon emissions. At present, hydrogen metallurgy technology is highly valued, and it is an important development direction in metallurgy field. This paper mainly summarizes the development status of hydrogen metallurgy technology at home and abroad under the background of peak carbon dioxide emissions and carbon neutrality, and the development trend of China steel industry under the background of hydrogen metallurgy. Based on the theoretical study of thermodynamics and kinetics of metallurgical process, the advantages and disadvantages of reducing iron oxide by H₂(CO) are compared and analyzed, and the reduction advantages of H₂ are defined. At the same time, the technical bottleneck of current hydrogen metallurgy development is discussed, and the future development of hydrogen metallurgy technology is prospected, which provides theoretical basis for the development of hydrogen metallurgy technology.

The traditional gas-compression refrigeration technology can no longer meet the requirements of human society for environmental protection and energy conservation. The development of new refrigeration technology has drawn increasingly growing attention in recent years. Compared to the traditional gas-compression refrigeration technique, solid-state cooling technology has aroused extensive interests owing to the high efficiency and environmental friendliness. The principle of solid-state cooling is to change the environment of external field (such as magnetic field, electric field and stress field) of a material, and change the properties (structure, magnetic moment, etc.) of the material accordingly, thus produce the corresponding caloric effects, namely magnetocaloric effect, electrocaloric effect and mechanocaloric effect (elastocaloric effect, barocaloric effect). The key for promoting the solid-state cooling technology lies in the development of room temperature caloric materials that exhibit giant entropy change, wide working temperature interval and high operation stability. Among them, the elastocaloric cooling based on the elastocaloric effect (eCE) induced by uniaxial cyclic stress in shape memory alloys (SMAs) is one of the most promising solid-state cooling technology.
   The eCE in SMAs originates from the martensite transformation enthalpy, i.e. in the process of stress-induced martensite transformation and inverse transformation, the material releases and absorbs the latent heat of phase transformation, and the solid refrigeration can be realized by means of refrigeration cycle device. In the course of the study, elastocaloric cooling technology presemts many advantages, including large and reversible adiabatic temperature change, simple stress-driven method and wide application range of temperature. However, the eCE materials are still exist problems like short fatigue life, large hysteresis loss and uneven strain distribution. In 2014, the elastocaloric cooling technology was ranked as the first of 17 new alternative technologies for gas-compression cooling by U.S. Department of Energy, which has been recognized as the most promising cooling systems.
   Rencntly, scientists have measured large caloric effects in many SMAs near room temperature, such as Cu-Zn-Al, Ti-Ni-(Cu), Fe-Pd, Ni-Mn-Sn-(Cu), Ni-Mn-In-Co. The adiabatic temperature change ΔTad and the isothermal entropy change ΔSiso are the main measuring parameters of eCE, which can be obtained by direct or indirect methods. ΔSiso can be calculated by the stress-strain curve of SMAs and Maxwell’s equation, which can characterize the eCE indirectly. Moreover, due to the simple driving method of the eCE, a more convenient method is measuring the ΔTad directly, which means measure the temperature before and after martensite transformation by a precise temperature measuring equipment. This method can not only characterize the magnitude of eCE directly, but also acquire the changing details in the process of eCE, like the trend or location of temperature changes in eCE materials.
   In this article, the research progress of eCE in traditional SMAs (Cu-, Ni-Ti- and Fe-based) and ferromagnetic SMAs (Ni-Mn-based) are reviewed. The pros and cons of various SMAs for eCE are analyzed. Finally, the development prospects of elastocaloric materials is proposed.

Skin is the largest organ in human body, and play a crucial role as barrier. When human skin is damaged, skin dressings are usually used to repair the wound. It is of great significance for repair of human skin injury and production of medicine and cosmetics to develop skin dressings that can imitate normal human skin. With the rapid development of skin dressings, various types of skin dressings continue to emerge. In this article, the current research status of skin dressings is elaborated, including wound dressings and artificial skin in terms of their type, structure and property. In addition, four types of skin dressings, namely traditional type, biological type, synthetic type, and composite skin dressings are introduced. The composition and features of the above four types of skin dressings are discussed and compared in detail. Besides, the types of commercial artificial skin is briefly introduced as well. Finally, the future development of skin dressings is proposed.

Hydrogen is considered to be a clean energy source due to its high efficiency, power density and limited environmental impact. Chemical hydrogen storage materials require a high hydrogen storage capacity. Ammonia borane has been identified as an attractive candidate for hydrogen storage due to its high hydrogen content (19.6%) and stability under ordinary storage conditions. Catalyst is the core technology as ammonia borane is not easy to release hydrogen at room temperature without catalysts. Metal catalyst can significantly increase the rate of hydrolysis, which is the key factor affecting the hydrogen evolution of ammonia borane. However, metal catalyst particles are generally easy to become agglomerate and be oxidized. A variety of supporters have been chosen to disperse the catalyst, in order to leave more act positions on the catalysts which allows ammonia borane release hydrogen more quickly. Therefore, the catalytic effects of different catalyst supporters on hydrolysis of ammonia borane are discussed in this paper.

Although conventional nanocarrier systems can improve the in-vivo drug biodistribution characteristics and cellular uptake behavior, challenges of passive targeting in liver tissue and short systemic circulation time caused by reticuloendothelial system entrapment cannot be ignored. With the continuous development of bioengineering technology, more and more evidence has revealed that application of biomimetic nanocarriers derived from cell vesicles can overcome the defects of synthesized drug nanocarriers. Platelets produced by megakaryocytes in bone marrow are the smallest cells in blood, which participate in numerous physiological processes involving hemostasis, wound healing and thrombosis formation, and also play the important roles in inflammation, immune regulation and tumor metastasis. By utilizing the unique functions of cell membrane proteins, platelet vesicle carriers can effectively transport drugs to achieve long time circulation, active targeting and immune system escaping effects. Till now, numerous drug nanocarrier systems based on platelet derived vesicles have been successfully developed to transport various kinds of cargos including small molecule drugs, inorganic compounds, nucleic acid and nanoparticles for the treatment of cardiovascular diseases, malignant tumors and infectious diseases. Given the continued focus and intensive studies on platelet vesicle drug carriers, this paper gives a comprehensive review of the latest researches as well as the perspective discussion on challenges and development trends.

A memristor is a circuit element that can store information or perform calculations by changing its resistance. However, a pulse circuit with a pulse width of up to nanosecond is a difficult task, and limits the speed at which the memristor can change resistance. The pulse width of a pulsed laser is very short and can easily reach the nanosecond level. Cu₂Se is a typical thermoelectric material with both hole and Cu⁺ as carriers under the graded temperature field. The movement of Cu⁺ is irreversible without graded temperature field. Besides, the energy consumption for establishing thermal or graded temperature field (10 000 ℃=1 eV) is much less than that for electric field, laser, oxidation-reduction reactions, etc. Therefore Cu₂Se might be a kind of thermoelectric memristor material. In this work, the memristor electrical properties of Cu₂Se samples were measured, and the temperature distribution models of Cu₂Se samples at different times in the thickness direction were simulated. The thermoelectric potential and electric field intensity at different positions were calculated according to the thermoelectric property of Cu₂Se. As the result, the electric field intensities of Cu₂Se samples at different positions along the thickness direction after pulsed laser were obtained. The experimental results show that the direct voltage and inverse voltage of 70 μm thick Cu₂Se samples with 1 mm probe spacing are 0.47 V and 0.40 V, respectively, Cu₂Se thermoelectric materials do not need an initial high voltage to stimulate the memristor effect. Also, the mechanism of Cu₂Se ther-moelectric memristor has been proposed. The calculation results indicate that the electric field intensities (50—0.56 V/mm)along the thickness direction is greater than the electric field intensities required for resistance transformation (0.5 V/mm). Therefore, the feasibility of laser irradiation Cu₂Se thermoelectric memristor devices is proved theoretically.

According to the lack of clear reference for the selection of grouting materials for roads non-excavation reinforcement, the types and proportions of the commonly used road grouting materials are investigated systematically. Based on the statistical analysis, the ratios of cement based grouting material and geopolymer grouting material are recommended. The effect of the density of polymer grouting material on water absorption and compressive strength is determined. The results show that the recommended water-cement ratio of cement paste grouting material is 0.46-0.67, and the ratio of cement mortar is mcement∶mwater∶msand=1∶(0.46-0.59)∶(0.31-0.73). The recommended range of the sodium silicate modulus, the water-cement ratio and the mass fraction of sodium silicate of the geopolymer grouting material are 2.3-3.1, 0.49-0.67 and 7.27%-9.73%. With the increase of density of solidified polymer grouting material, the compressive strength increases and the water absorption reduces.

Black phosphorus was first successfully synthesized in the bulk form in 1914. After remaining silent for 100 years, the novel 2D-nanomaterial formed by attenuating bulk black phosphorus into the multilayer state, i.e. 2D black phosphorus, was firstly obtained in 2014. This layered 2D semiconductor material consisting of only phosphorus atoms has from then onward been drawing intensive interest in the field of low-dimensional inorganic semiconductor because of its rich variety of special electrical and optical properties such as appropriate tunable direct bandgap, high carrier mobility, high leakage current modulation ratio, relatively high on-off current ratio, good electrical and thermal conductivity and strong in-plane anisotropy. 2D black phosphorus is an intrinsic p-type material with a series of excellent properties, but the production of large-area phosphorene (i.e. monolayer black phosp-horus) film has so far remained unrealized due to the instability of 2D black phosphorus. This article intends to make a review of the research progress on 2D black phosphorus. We here introduce systematically the structure, preparation and properties of 2D black phosphorus, also offer a detailed description of its physical properties (electronic, optical, mechanical, thermal, magnetic) and chemical stability. The paper ends with the rough summary and discussion on the research prospect of this emerging new material with sharp momentum.

Currently, blast furnace ironmaking process and direct reduction method are the most mainstream ironmaking technologies. Blast furnace ironmaking has large capacity and high efficiency, whereas the contradiction between high coke ratio and high energy consumption of blast furnace and the green development of the environment has become increasingly prominent. The innovative research and development of coal-based, gas-based direct reduction or smelting reduction technology continuously develop into efficiency improvement and cost reduction. However, the technology with the high-efficiency utilization of carbon as the core under the existing process is constantly approaching the potential limit of carbon reduction. With the purpose of carbon neutrality and carbon peaks, the steel manufacturing industry is actively developing and exploring alternative reduction technologies for iron ore. The rational use of H₂ in the ironmaking process has become more and more significant in energy reducing and CO₂ emissions. This article discusses the basic research of hydrogen reduction of iron ore, the technical advantages of hydrogen metallurgy and the problems of my country's hydrogen metallurgical technology achievements and development. It was proposed and verified that the microwave irradiation method could obtain iron powder by hydrogen-rich or pure hydrogen smelting. In the comparative experiment, microwave heating has a better reduction effect than conventional heating methods and H₂ had a better reduction rate (78.6%) than that of CO(3.1%) at 1 100 ℃ on iron.

Scanning Kelvin probe force microscopy (SPFKM) is a material measuring and characterizing technique which applies scanning Kelvin probe on the basis of atomic force microscopy (AFM) and has been gaining momentum in recent years. It involves simultaneously the nanometer-level topography measurement and the in-situ high-resolution volta potential mapping, thereby providing a novel insight in investigating the mechanisms of materials’ corrosion behaviours. The present paper sketches out the principles with respect to the two working modes of SKPFM, summarizes the unresolved issues that have emerged in SPFKM’s application, and also renders a comparative discussion between SKPFM and the traditional SKP technique. The review offers an elaborate delineation about the application of SKPFM in corrosion science, and ends with a rough description of the opportunities and challenges.

As a widely used process and method in additive manufacturing technology, direct ink writing has the advantages of low equipment cost, high material utilization rate, simple operation process, low energy requirement and environmental friendliness. In recent years, direct ink writing technology has become one of the research hotspots of additive manufacturing technology. This paper introduces the mechanism and advantages of direct ink writing technology, from the three aspects of mixed material printing, material mixed printing and functionally graded material printing, elaborates the application of direct ink writing technology in biomedicine, construction engineering, energetic materials and food engineering, etc., and summarizes the technical difficulties and key issues of printing methods of different materials.It also discusses the challenges and the future development trend of direct ink writing technology.

At high burnup, fission product lanthanide accumulate is substantial and obviously contributes to fuel-cladding chemical interaction upon migration to the Fe-based cladding interface. By doping with specific elements into the fuel alloy, the lanthanide accumulates may be precipitated into stable, non-migratory, and non-reactive phases within the fuel and thus significantly reduce and/or delay the onset of fuel-cladding chemical interaction. Experimentally, indium has been selected as the fuel dopant due to several attractive properties, such as its compatibility with the fuel, chemical inertness with cladding materials and reactivity with the lanthanides. In this study, first-principles calculations were performed to investigate ground-state properties of the indium-lanthanides (La, Ce, Pr and Nd) intermetallic compounds. The electronic and magnetic properties of InLa, CeIn₃, αInPr and In₃Nd have been calculated in the presence of spin-orbit coupling, and anti-ferromagnetic ground state structures have been found to be the most stable phases for these compounds. In addition, the thermodynamic properties of these four compounds at given temperatures and pressures have been calculated. The study may lead to a better understanding of the function of indium of binding and stabilizing lanthanide fission products.