Abstract: High-entropy materials (HEMs) designed with a new material design philosophy have recently emerged as a new type of advanced materials. In contrast to traditional alloys where one or two elements dominate the structural composition, HEMs comprise multiprincipal metallic or metalloid elements, generally ≥5 and in equiatomic or near-equiatomic ratios, thereby possessing high mixing entropy and generally forming a single-phase solid solution structure during solidification process. Because of their unique atomic structures, HEMs exhibit excellent properties such as high strength, hardness, corrosion resistance and structural stability at elevated temperatures. Hence, HEMs have great potential to be utilized in various high-tech areas, such as aerospace, high-temperature and nuclear energy fields, etc. HEMs have sparked great interests in the fields of materials and substantial progress has been made over the years. Powder metallurgy (PM) is an advanced technology that is often used to fabricate high-performance metal-based and ceramic composite materials possessing a metastable structure, such as nanocrystalline or supersaturated solid solution phases. In particular, it can also be applied to synthesize advanced materials with unique structures and properties that are difficult to achieve using conventional casting methods. Recently, PM has been extensively applied in studying HEMs, thereby considerably expanding their application range. In this review paper, we first introduce the concept and theories related to HEMs and briefly summarize research activities and progresses made with regards to the applications of PM in HEMs, including synthesis methods of powders, formation of bulk HEMs, and typical HEMs (i.e., nanocrystalline high-entropy alloys (HEAs), refractory HEAs, lightweight HEAs, dispersion strengthened HEAs, and high-entropy ceramics) fabricated using PM. In particular, we place emphasis on the mechanical properties and deformation behaviors of HEMs, specifically, the strengthening mechanisms in some typical HEAs fabricated by PM. Finally, the future prospects of HEMs are also briefly outlined.
Abstract: The bionic flapping-wing aerial vehicle (FWAV) is a kind of aerial vehicle that imitates birds and insects and generates lift and thrust forces using active wing movement. Given its advantages, such as high flight efficiency, strong maneuverability, and good imperceptibility, FWAVs have attracted considerable attention from researchers in recent years. Given its compact structure and easy operation, the small FWAV can adapt itself to complex environments. However, some restrictions are also imposed on its onboard load capacity and battery endurance time. That is, sensors with large weight and high power consumption are no longer suitable for FWAVs in many scenarios. To the best of our knowledge, most of the information obtained by organisms from nature is acquired through vision. As an efficient way to obtain information, vision plays an irreplaceable role in the application of FWAVs. Vision sensors have many advantages, such as light weight, low power consumption, and rich image information. Therefore, these sensors are suitable for FWAVs. With the development of microelectronics and image processing technologies, visual perception systems of the FWAV have also made important progress. First, this study introduces the visual perception system of several representative FWAVs at home and abroad, which can be classified into two categories, i.e., onboard and off-board visual perception systems. Then, this study briefly reviews three key technologies of the visual perception system of FWAVs, namely, image stabilization, object detection and recognition, and object tracking technologies. As a result, research on the visual perception system of FWAVs is still at the initial stage. Finally, this study provides the future research directions of the visual perception system of FWAVs, such as image stabilization, onboard real-time processing, object detection and recognition, and three-dimensional reconstruction.
Abstract: Every significant technical advancement of the steel industry has depended on the support of refractories used as lining materials in various smelting containers. With the increasing demand for high-quality steels, the precise control of inclusions has become increasingly important. Existing technologies and equipment can effectively reduce the amount and average size of inclusions, but they cannot guarantee the complete removal of large-sized ones. In the steel-making process, refractories in close contact with molten steel are a main source of large-sized non-metallic inclusions; these can become bottlenecks, restricting improvements in steel quality. Based on this problem, the design, preparation, and application of new functional refractories become a critical focus for further development in the steel industry. These refractories are required to possess not only excellent thermo-mechanical properties (i.e., zero or reduced contaminant for the molten steel), but also the ability to remove inclusions with a high melting point in molten steel. However, available refractories are in their primary stages depending on experience, resulting in no breakthroughs in the precise control of inclusions, and even contamination of molten steel. This study focused on two new refractory materials, namely large-sized Al4SiC4 with controllable morphology, and Al2O3?MgO?CaO (CMA) with a ternary-layer structure. Preliminary experiments show that, with the introduction of the large-sized Al4SiC4, oxidation resistance of MgO?C bricks is improved, and the loose structure resulting from the oxidation of carbon-containing materials can be repaired. CMA materials not only possess excellent thermo-mechanical properties and high slag resistance, but also can produce refining slag phases with a low melting point. This can contribute to the floating of inclusions, thus exhibiting the potential for purifying molten steel. These new, functional refractories should offer strong support for the further development of high-quality steels.
Abstract: Tannic acid (TA) is widely used to protect metals from corrosion because it is environmentally friendly and inexpensive. However, the single effect of TA used as corrosion inhibitor has been widely investigated and studies focusing on the corrosion inhibition effect have been limited. Some studies have proven that the addition of a compound corrosion inhibitor can considerably improve the corrosion inhibition efficiency of an inhibitor, and this method can be applied to TA. The corrosion inhibition effect of the combination of two compounds, FeCl3 and Na2MoO4, with TA was analyzed on carbon steel Q235. Copper sulfate drip test, soaking test, and electrochemical test were used to compare the film-forming characteristics and corrosion inhibition effect of the combination of FeCl3 and Na2MoO4 with TA on carbon steel surface. The discoloration time of copper sulfate droplets initially increases and subsequently decreases with the increase in the concentrations of FeCl3 and Na2MoO4 in TA. At the end of the soaking test, fewer pits are observed on the surface of carbon steel following the addition of FeCl3 and Na2MoO4 to the TA inhibitor. Based on the results of the electrochemical tests, the corrosion inhibition effects of the TA inhibitor on carbon steel before and after the addition of FeCl3 were compared. The results reveal that the charge transfer resistance of the two inhibitors increases from 2698 to 3711 Ω·cm2, and the corrosion current density decreases from 2.734 to 1.902 μA·cm?2. A clear increase and decrease in the charge transfer resistance and corrosion current density, respectively, are observed once Na2MoO4 is added. Further, the charge transfer resistance increases from 2698 to 5100 Ω·cm2, and the corrosion current density decreases from 2.734 to 0.714 μA·cm?2. The following conclusions can be drawn from these results: the addition of FeCl3 or Na2MoO4 to TA can both improve the corrosion inhibition effect of TA; the compound system of TA and Na2MoO4 exhibits a better corrosion inhibition effect compared with the compound system of TA and FeCl3.
Abstract: Dopamine (DA) and uric acid (UA) are small biological molecules involved in many important processes in the human body. Their concentrations are closely related to human health. Abnormal concentrations of these molecules lead to various diseases, such as Parkinson's and gout, so monitoring of DA and UA in blood and urine, respectively, is very meaningful in clinical analysis. Electrochemical sensor detection is a widely-used method in the field of biological analysis owing to its advantages of simple operation, high sensitivity, low cost, environmental friendliness, etc. In this paper, titanium nitride (TiN) nanomaterial with chrysanthemum morphology was synthesized by hydrothermal and reduction nitridation methods toward preparation of an effective electrochemical sensor for human testing. It was further combined with reduced graphene oxide (rGO) through the hydrothermal method to form a titanium nitride-reduced graphene oxide (TiN-rGO) composite material. The phase and morphology of the material were characterized and analyzed by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and other test methods. The results show that the TiN-rGO composite material maintaines the three-dimensional chrysanthemum-like morphology of TiN, and the transparent and wrinkled morphology of rGO. The chrysanthemum-like TiN is uniformly coated with the layered rGO. The TiN-rGO/GCE electrochemical sensor was then prepared by modifying the glassy carbon electrode (GCE) with TiN-rGO composite material for the determination DA and UA levels in the human body. Due to the synergistic effect of TiN and rGO in the composite, the constructed electrochemical sensor exhibits excellent electrochemical performance. The detection results show that the detection limits of DA and UA for the TiN-rGO/GCE electrochemical sensor are 0.11 and 0.12 μmol·L?1, respectively, and the linear ranges are 0.5?210 μmol·L?1 and 5?350 μmol·L?1, respectively. TiN-rGO/GCE electrochemical sensor also has good anti-interference, reproducibility and stability, and has been successfully applied in the detection of DA and UA in real human samples.
Abstract: Hexagonal boron nitride nanosheets (h-BNNSs) are two-dimensional nanomaterials whose structure, similar to graphene, is called white graphene. They have excellent physical and chemical properties. Few-layered and monolayer h-BNNSs have more extensive applications compared to block BNs due to their wider band gap and stronger insulation. However, the existing preparation methods have the disadvantages of uncontrollable product size, low yield, high cost, and pollution. Researchers are striving to develop an efficient and cheap method, and some have tried to prepared h-BNNSs through evaporation and recrystallization. However, it is difficult to control morphology in this method and prepared products are usually thick with uneven size distribution. Meanwhile, vacuum freeze-drying has been widely used in functional porous ceramics due its simple operation, controllability, and environmental friendliness. In this study, based on the two-step process of precursor synthesis and ammonia nitriding, few-layered h-BNNSs with large surface areas were successfully synthesized on a large scale by controlling key factors of precursor synthesis, such as ratio of atoms B to N in the raw material, dispersant, and drying method. The optimum preparation was using boric acid and urea with a molar ratio of 1∶30 as the source of B and N, and using methanol/deionized water as dispersant to obtain the precursors by vacuum freeze drying. Precursors were then transformed from ammonia vapor to nitride for 3 h at 900 ℃. The product was characterized by X-Ray diffraction, X-ray photoelectron spectroscopy, Raman spectra, thermogravimetric analysis, and differential thermal analysis for phase and molecular structure, and scanning electron microscope, atomic force microscope, transmission electron microscope, and N2 adsorption-desorption isotherms for microstructure and specific surface area. Results indicate that the products are h-BNNSs with high purity, two to four atomic layers, 1 nm thickness, and with a high specific surface area of 871.8 m2·g?1, similar to the microstructure of graphene. Single product mass averages 240 mg and average yield is steadily 96.7%. This method is economical, simple, and easy to operate. It could achieve macro-synthesis of few-layered h-BNNSs with a large area, conducive to research on boron nitride in various field applications, such as boron nitride/graphene composite materials, nano-electronic devices, pollutant adsorption, hydrogen storage, etc.
Abstract: Platinum-based catalysts have been widely used in fuel cells due to their excellent activity in oxygen reduction reactions. At the same time, using Pt in large quantities is costly. To solve the high cost of fuel cell catalysts, research into low-Pt-content and highly efficient catalysts with special structures has attracted considerable attention. However, conditions required for synthesis of these catalysts are highly restrictive and the synthetic methods are energy-intensive and harmful to the environment. In this study, Cu nanowires (NWs) were synthesized hydrothermally at 80 ℃. Growth of the Au shell on the Cu NWs, achieved through a liquid phase reduction method, was carried out in aqueous solution at low temperature. Finally, Pt layers were deposited on the surface of the Au?Cu NWs by Galvanic displacement between the uncovered copper NWs and chloroplatinic acid. Subsequently, Pt?Au?Cu ternary core-shell catalysts were constructed. The as-synthesized catalysts were characterized in depth using scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM). The growth mechanism of the Pt?Au?Cu NWs was also explored. Results show that the phase composition of the synthetic NWs is monolithic Cu with an average diameter of about 83 nm; average diameter of the Au?Cu NWs is about 90 nm, and the small particles attached to the surface are Au. After Pt loading, the Pt?Au?Cu ternary core shell structure of the NWs is obtained with an average diameter of 120 nm. It is confirmed that the formation of the surface Au nanoparticles on the Cu NWs depends on the heterogeneous nucleation and growth mechanism, and that the growth mode conforms to the Stranski-Krastanow (S-K) mode. Pt and Cu interdiffusion exists during Pt loading, so that the surface of the NW is mostly Pt particles and the whole is a CuPt alloy phase. This study demonstrates a new strategy in synthesis of ternary core-shell NWs.
Abstract: Direct methods of plastic analysis are widely used in composites analysis to determine material strength for safety assessment or lightweight optimization design. Multi-scale processing of periodic heterogeneous composite material is needed due to its existing of microstructure. The standard method is to determine the macroscopic properties from the calculation results of microcosmic representative volume elements (RVEs) by using the homogenization theory. However, in current practice, there are some disadvantages of transforming the micro strain domain to the macro stress shakedown domain when considering multiple external loads. The domain cannot fully demonstrate the shakedown condition, and it is impossible to evaluate a known loading combination only from the knowledge of whether the load leads to the shakedown state. To overcome this disadvantage, a new comprehensive approach was proposed to enhance endurance limit strength of composites under variable loads for long term. Considering the example of in-plane strength analysis, for microcosmic RVEs, a new set of boundary condition was defined in the form of uniform strain. The boundary condition was derived from the elastic response under unit loads by using Hook’s law and stiffness matrix. The resulting elastic stress field was used later for plastic shakedown analysis. Based on the lower bound theorem of plastic mechanics, optimization programming for load factor was performed, and after proper mathematical reformulation, the conic quadratic optimization problem could be solved efficiently. Macro-stress shakedown domain can be obtained after scale-transformation of the RVE results. The bases of this stress domain are unidirectional stress in geometry space. The stress amplitude of a structure can be evaluated by this domain for determining the shakedown state in a simple and practical manner. Further, changes in the boundary condition of RVE do not affect the limit and elastic analysis. Finally, few numerical examples were presented for verification and illustration. This approach can be expanded to three dimensions and employed for more complex structures.
Abstract: Non-metallic inclusions generally deteriorate the quality of stainless steel products, such as skin laminations or line defects on the rolled strip in stainless steel. Thus, the formation mechanism of non-metallic inclusions in 202 stainless steel was investigated with industrial trials and thermodynamic calculation. Steel samples were analyzed by scanning electron microscopy and energy dispersive spectroscopy. Compositions of the steel samples were determined by inductively coupled plasma-optical emission spectrometer. After Si?Mn deoxidation, the main inclusions were spherical Ca?Si?Mn?O inclusions during LF refining process. The liquid phase region of the Mn?Si?O phase diagram was affected by the residual aluminum content in Si?Mn deoxidized stainless steel. 1×10?5 mass fraction of aluminum in steel enlarged the liquid phase region of the Mn?Si?O phase diagram. However, more than 3×10?5 mass fraction of aluminum led to the formation of alumina inclusions and the reduction of the liquid phase region of the Mn?Si?O phase diagram. After the continuous casting process, the main inclusions in the steel were changed from Ca?Si?Mn?O to Mn?Al?O. Compared with the steel sample taken during the LF refining process, the MnO and Al2O3 content of inclusions in the continuous casting samples increased significantly, while the content of CaO and SiO2 decreased significantly. At the same time, the amount of inclusions increased from 5.5 mm?2 to 11.3 mm?2 after continuous casting. Combined with thermodynamic calculations, it was found that Mn?Al?O inclusions were formed during solidification, which became the main type of inclusion after continuous casting. In addition, the effect of aluminum content on the formation of oxide inclusions during continuous casting was discussed. Thermodynamic calculation indicated that the alumina inclusions were formed in the steel containing more than 3×10?5 mass fraction of aluminum during continuous casting. High aluminum content promoted the formation of alumina and inhibited the formation of Mn?Al?O inclusions during solidification.
Abstract: Controlling the balance between mechanical properties and stress corrosion resistance of Al–Zn?Mg alloys by aging tempers has long been an active focal point of research. Traditional peak-age can improve the mechanical properties, but the continuous precipitate at the grain boundary reduces the stress corrosion resistance of the alloy. While alloys in over-aged (T73) condition show good resistance to stress corrosion, their mechanical properties will drop significantly. In this paper, tensile properties, resistances to stress corrosion, and microstructures of the Al–Zn?Mg alloy, in interrupted aged (T5I4, T5I6) and traditional (T5, T73) tempers, were studied using a tensile test, a slow strain rate tensile test, and transmission electron microscopy. Results reveal that the tensile strength of T5I4 temper is 400.0 MPa, higher than that of T5,T73 tempers, while the stress corrosion resistance is clearly compromised, with index of slow strain rate testing, ISSRT, of 5.7%, significantly larger than that of the other three aging treatments. The tensile strength of the T5I6 temper increases to 408.5 MPa, and the stress corrosion resistance is also improved, to ISSRT=3.2%, significantly lower than that of T5 and T5I4 tempers. Volume fraction (8.8%) and average particle diameter (2.0 nm) of intragranular precipitates of T5I4 temper has the minimum value among the four aging treatments, and there are large numbers of fine precipitates distributed continuously at grain boundaries. In the T5I6 temper, the number of intragranular precipitates increase significantly, and the volume fraction of intragranular precipitates is 24.6%, larger than that of the other three aging treatments. In addition, the average particle diameter (4.1 nm) of the intragranular precipitates of the T5I6 temper is larger than that of the T5I4 temper, but is still smaller than that of the T5 and T73 tempers. Precipitates at the grain boundaries of the T5I6 temper are unevenly distributed, and significantly larger than those of the T5I4 temper.
Abstract: Characteristics of molten metal heated with microwaves were the focus of this study. A series of experiments on the direct microwave heating of molten copper and molten iron were conducted in a MobileLab-W-R microwave workstation; both metals were effectively heated by direct microwaves. Effects of indirect versus direct heating were comparatively analyzed using different types of heating chambers. The direct heating method was then further investigated, taking microwave power, mass of molten metal, and temperature into consideration. The mechanism of direct microwave heating of molten metal was discussed. The results show that microwave can directly heat molten iron and molten copper at high rates that increase linearly with increasing microwave power. Heating rates of molten iron are similar to those of molten copper at constant mass and microwave power. However, the mass of molten iron has no clear linear relationship with heating rates due to the involvement of other factors, such as surface area of the molten iron and distribution of the microwaves. According to the theoretical analysis, when the states of copper and iron are transferred from solid to liquid, their resistivities increase, but their permeabilities drop significantly. As a result, the skin effect depths of microwave in molten copper and iron are clearly larger than those in the solid metals. Conductivity loss is the main mechanism of achieving direct microwave heating of molten metal. Microwave energy can be absorbed in four ways: collisions between electrons and nucleus, rapid liquid surface renewal, hindering of internal defects of electron movement, and atom movement and collision. Absorbed microwave energy can be transferred into the internal energy of the molten metal.
Abstract: Due to exposure to air during rolling processes, a layer of oxide scale always coats the surface of the hot-rolled steel plates. During the subsequent cooling processes, the FeO in the oxide scale undergoes a eutectic reaction. The formation of a lamellar structure (Fe+Fe3O4) during this reaction is influenced by different cooling methods. The addition of alloying elements, however, also affects the eutectic reaction. The final oxide scale, hence, varieswith different compositions. For 700-MPa grade high strength steels, poor control of iron oxide scale is detrimental to the surface quality; such surface defects as iron oxide scale shedding, surface red rust, pit, are incurred. These defects, however, affect the overall performance of the steel. Consequently, the improvement of the surface quality of hot-rolled steel by controlling the iron oxide scale, without compromising the mechanical properties, has attracted the interest of many researchers. In this paper, the effect of cooling temperature and cooling rate on the structural transformation of tertiary oxide scale during hot-rolling was studied. A sample of 700 L steel grade was used. The study was carried out by the thermogravimetric analysis (TGA). The results show a "nose temperature" range of 450?500 ℃ for the 700 L eutectoid transformation. The FeO shows the shortest incubation period of eutectoid transformation, hence, is prone to eutectoid transformation, forminga large number of eutectoid phase (Fe+Fe3O4). Addition of alloying elements such as manganese (Mg), niobium (Nb), and titanium (Ti) to the 700 L steel lead to grain refinement in the steel. It also increases the amount of diffusion channel of ions that participate in the eutectoid phase transformation. Consequently, the eutectoid transformation is delayed, and the eutectoid " C” curve shifts to the left. This is comparableto the eutectoid transformation rule of oxide scale on the surface of other steel grades.
Abstract: A coordinated autonomous control algorithm of unmanned aerial vehicle (UAV) swarm was proposed to reduce the complexity of UAV swarm control and solve the problem of changing topological structures in long-distance flight of UAV swarms efficiently. As the UAV swarms, especially fixed-wing ones, fly in a close formation, the influence and benefit of aerodynamic coupling between UAV in swarms should be considered. This paper focused on the application of biological swarm behavior mechanism, which can be used to form the shape of formation and adjust the topological structures of UAV swarm, and not the models of the aerodynamic coupling between UAVs in swarms. The distributed swarm control model of biological swarms based on the behavioral mechanism of Anser cygnoides formation was presented. A novel distributed swarm control system based on the behavioral mechanism of Anser cygnoides formation for low-cost UAVs was developed. Anser cygnoides is a common bird that lives in swarms. Its self-organizing network and formation topology behavior on the manner of migration exhibit high similarities with the application of UAV swarm. The paper designed an experimentation with a UAV swarm system using quadrotors, which communicate wirelessly using a Wi-Fi, to test and verify the feasibility of the proposed novel distributed swarm control algorithm. The field experimentation involved flying the five low-cost quadrotors in a " V” formation, and the position exchange of UAVs was achieved during the experimentation. The whole formation with the five quadrotors flew at a continuous speed during the whole experimentation, whereas the flight mode of fixed-wing UAV was simulated. The field experimentation shows that the formation mechanism of the migrant bird helps in realizing the distributed formation reconfiguration control of the UAV swarm and improves the robustness of the UAV swarm flight and verifies the feasibility of the novel distributed swarm control algorithm.
Abstract: In recent years, cement-based composite materials have been widely used in mine filling, which can well solve the hidden danger of goaf collapse. However, when the water table and surrounding rock moisture content change, the filling materials will be in the process of dry and wet alternation, which will affect the long-term stability of the filling materials and goaf. In order to explore the influence of dry and wet cycles on the long-term stability of cement-based composite filling materials, taking water-cement ratio 4∶1 cement-based composites as the research object and using ETM mechanical test system, X-ray diffraction (XRD) and scanning electron microscopy (SEM) device, uniaxial compressive strength tests were carried out in the state of "water saturation" and "water loss" under different dry-wet circulation. The influence mechanism of dry-wet circulation was discussed by phase analysis and microstructure. The results show that as the number of dry-wet circulation increases, the loss rate increases gradually while the water content and bulk density decrease, the peak intensity first increases and then decreases, and the increase is as high as 9% under the saturated state. The water loss rate, water content and bulk density do not change much under the condition of "water loss", while the peak strength decreases from the initial state to up to 13.5%. The elastic modulus and residual strength of the two states show a downward trend. Through mechanism analysis, it is found that carbonation reaction is the main reason for material strength reduction in the "dry" process, while the CaCO3 and other materials are converted into ettringite (AFT) and thaumasite (TSA) with some bearing capacity during the absorbing water process in "wet" process, which is the main reason for the strength recovery of materials. However, the recovery ability is limited, and the long-term dry-wet circulation will adversely affect the stability of cement-based composite filling material.
Abstract: Cemented tailings backfill (CTB) technology, an innovative mode of tailings management, has been widely applied in many metal mines worldwide due to its advantages of safety, environmental protection, and high economic benefit. During the mining process, CTB should have sufficient mechanical strength to maintain the stability of the underground stopes and provide a safe environment for workers and mining equipment. However, in deep mining, cracks and imperfection in CTB are usually generated by the extraction of adjacent stopes, blasting disturbances, and stress concentration. Existence of these cracks weakens the engineering properties. It causes instability of backfill stopes and increases ore dilution. At present, the mechanical strength of CTB structures is improved by increasing binder content, which directly leads to an increased backfilling cost. Hence, to solve the problems mentioned above, CTB specimens were prepared with cement-tailings ratios of 1∶10 and 1∶20, and polypropylene fiber contents of 0, 0.05%, 0.15%, and 0.25% (by dry weight of tailings and cement). The effect of fiber content on the mechanical strength and deformation properties were investigated by conducting unconfined compressive strength (UCS) tests. Referring to scanning electron microscopy (SEM), the mechanism of fiber reinforcement is discussed. Results indicate that the yield stress of fresh CTB mixtures increase linearly with increasing fiber content, and the rheological characteristic of the mixtures conformed to the behavior of Bingham. UCS values of CTB increase with increasing fiber content, but decrease when the fiber content is > 0.15%. Optimal fiber content is 0.15%. It is found that fibers can effectively delay the expansion of cracks and constrain the deformation of backfill. The post-peak strain softening and residual strength are improved by the addition of fibers. Failure characteristics of CTB are transformed from brittleness to ductility due to the mixed fibers. The reinforcement effect of fiber is mainly controlled by the adhesion and friction between fibers and tailings-cement matrix. The overall objectives are to improve current understanding of the mechanical properties of CTB, thereby reducing the risk of clogged pipelines and higher backfilling costs as well as improving the stability of CTB structures.
Monthly, started in 1955 Supervising institution：Ministry of Education Sponsoring Institution：University of Science and Technology Beijing Editorial office：Editorial Department of Chinese Journal of Engineering Publisher：Science Press Chairperson：Ren-shu Yang Editor-in-Chief：Ai-xiang Wu ISSN 2095-9389CN 2095-9389
