Theoretical and numerical simulation of critical gas supply of refuge chamber

The personnel in refuge chamber absorb O_2 and exhale CO_2 all the time. Supplying O_2 and removing CO_2 are the basic function of refuge chamber. After disaster occurs, the supply of the compressed air or oxygen for personnel in refuge chamber is limited. Thus, how to effectively use the compressed air and oxygen and try to improve the time of supply has a great significance. Supplying more oxygen will result in waste, while supplying less oxygen will cause its concentration to be lower, and harm life safety. This research uses the theoretical calculation and numerical simulation, finds critical gas supply for refuge chamber, and illuminates the change law of gas concentration with critical gas supply in refuge chamber,which provides theoretical guidance for effective use of compressed air and oxygen in refuge chamber.

Analysis of Damage Pattern of Road Bridge Landslide in Mountainous Area

Through on-site defect investigation,special inspection,and finite element simulation calculation of a high-speed upper-span(30+32+30)m prestressed concrete box girder bridge,the overall sliding force of the bridge on the right side of platform 0#is analyzed.In this situation,typical defects such as overall girder slippage,support dislocation,pier column deviation,and pier bottom side cracks have occurred in the overpass.At the same time,combined with simulation calculation analysis,it is interpreted that the 0#and 1#foundation has been damaged at a certain position below the ground line.The occurrence of broken piles has provided a reliable basis for the later reinforcement and maintenance of the bridge and ideas for emergency inspection and analysis of bridges damaged by the same type of landslides.

Simulating Calculation of Frictional Force between Mold and Billet

Assumption about the inner surface of mold is made according to the forming mechanisms of frictional force. The frictional force between billet and mold can be analysed by calculating the thermal shrinkage and the shearing strength of the meniscus.The model is used to calculate the maximum drawing speed at different conditions. The results are very satisfactory.

Superconductivity without dependence on valence electron density in Zn doped YBCO systems

This paper reports that the YBa2Cu3-xZnxO7-δ （x = 0-0.4） samples are researched by means of x-ray diffraction, calculations of binding energy, the positron experiments and variations of oxygen content. The results of simulated calculations, positron experiments and variations of oxygen content support the existence of cluster effect. Moreover, it is concluded that the cluster effect is an important factor on suppression of high-Tc cuprate superconductivity and the Tc does not depend on the density of valence electron directly.

Computational and experimental verification of a wide-angle metamaterial absorber

A metamaterial absorber is computed numerically and measured experimentally in a 150-THz^300-THz range.The measured absorber achieves high absorption rate for both transverse electric（TE） and transverse magnetic（TM） polarizations at large angles of incidence.An absorption sensor scheme is proposed based on the measured absorber and the variations of surrounding media.Different surrounding media are applied to the surface of the absorption sensor（including air,water,and glucose solution）.Measured results show that high figure of merit（FOM） values are obtained for different surrounding media.The proposed sensor does not depend on the substrate,which means that it can be transplanted to different sensing platforms conveniently.

Computer Simulating Calculation on the Microstructure Evolutions during Hot Strip Rolling of C-Mn Steels

The program to predict the microstructure evolutions during hot strip rolling of C-M n steels has been developed in this paper, BV using this program, the microstructure changes with the processing parameters were analysed in detail. showing not only a good agreement of prediction with the measured values, but also entirely possibility to optimize hot strip rolling precess by computer simulation

Cooling Water Flow Rate Calculation for Hearth of Large Blast Furnaces

The cooling water flow rate for hearth of large blast furnaces was calculated by simulation. The results show that the cooling water flow rate shall be above 4 200m3/ h for hearth of large blast furnaces; to meet requirements of the increasing smelting intensity and to ensure the safety at the end of the first campaign,the designed maximum cooling water flow rate should be 5 900m3/ h; according to the flow distribution stability and the calculated resistance loss,hearth cooling stave pipes with the specification of 76 mm × 6 mm shall be adopted to assure the flow velocity in pipes of hearth cooling stave in the range of 1. 9- 2. 3 m / s.

Guangdong Dapeng LNG cold energy utilization-C_2++ extraction process integration

This paper makes a study of some technical and engineering aspects by using C2 ＋ hydrocarbon separation facility at Guangdong Dapeng liquefied natural gas （GDLNG） terminal. In the C2＋ hydrocarbon extraction process, the cold energy contained in LNG will be utilized. In order to ensure the optimum operating conditions of the temlinal and C2 ＋ hydrocarbon extraction facility by optimizing the current operating processes of the terminal, the C2 ＋ hydrocarbon extraction facility construction plan is proposed. We conducted numerous calculations and simulations using such specific analysis software as PRO II 〈 version 7.0 〉. Additionally available flow data are used to verify the cyclic send-out rates from the terminal, thus establishing the current and future projected load factors. This study is intended to make sure that GDLNG can continue to supply gas via the pipeline system safely without interruptions and most significantly solves the effects of flow fluctuations at the terminal gasification send-out facility on the hydrocarbons extraction, ensuring optimum pipeline operations and ensuring safe and effective means for such C2＋ hydrocarbons extraction process as well. At the same time, the terminal is also in the optimum operation condition. This is very significant to the terminal safety operation and the energy conservation and emission reduction.

Analytical and Numerical Investigation on the Penetration Resistance of PUE/Honeycomb Aluminum Composite Structures

In this study,the penetration resistance of a polyurethane elastomer(PUE)/honeycomb aluminum composite structure was investigated.A finite element analysis model was constructed to predict the residual velocity of the projectile after penetrating the PUE/honeycomb aluminum composite structure,and the accuracy of the model was verified through experiments.Both the residual velocity of the projectile and the failure appearance of the target plate were accurately predicted by the model.In addition,the Cowper-Symonds model was used to describe the material properties of the PUE layer,effectively simulating the damage appearance of the PUE layer after penetration.Subsequently,based on the validated model,three different configurations of the PUE/honeycomb aluminum composite structure were designed on the basis of the original honeycomb aluminum composite structure with a polyurethane elastomer coating,maintaining constant mass of the composite structure,and the ballistic performance was predicted using the finite element model.The anti-penetration performance of the PUE/honeycomb aluminum composite structure was analyzed by examining the velocity changes of the projectile,the energy changes of each component,and the crushing of the honeycomb core layer.Finally,the influence of different projectile shapes on the ultimate ballistic performance of the structure was studied,and the reasons for the influence of warhead shape on the appearance of target plate failure were analyzed.

Synthesis of covalently bonded reduced graphene oxide-Fe_(3)O_(4) nanocomposites for efficient electromagnetic wave absorption

High-performance electromagnetic(EM)wave absorbers,covalently bonded reduced graphene oxideFe_(3)O_(4) nanocomposites(rGO-Fe_(3)O_(4)),are synthesized via hydrothermal reaction,amidation reaction and reduction process.The microstructure,surface element composition and morphology of rGO-Fe_(3)O_(4) nanocomposites are characterized and corresponding EM wave absorption properties are analyzed in great detail.It demonstrates that Fe_(3)O_(4) nanoparticles are successfully covalently grafted onto graphene by amide bonds.When the mass ratio of rGO and Fe_(3)O_(4) is 2:1(sample S2),the absorber exhibits the excellent EM wave absorption performance that the maximum reflection loss(RL)reaches up to-48.6 dB at 14.4 GHz,while the effective absorption bandwidth(RL<-10 dB)is 6.32 GHz(11.68-18.0 GHz)with a matching thickness of 2.1 mm.Furthermore,radar cross section(RCS)simulation calculation is also adopted to evaluate the ability of absorbers to scatter EM waves,which proves again that the absorption performance of absorber S2 is optimal.The outstanding EM wave absorption performance is attributed to the synergistic effect between dielectric and magnetic loss,good attenuation ability and excellent impedance matching.Moreover,covalent bonds considered to be carrier channels can facilitate electron migration,adjust EM parameters and then enhance EM wave absorption perfo rmance.This work provides a possible method for preparing efficient EM wave absorbers.

Science and technology in high-entropy alloys

As human improve their ability to fabricate materials, alloys have evolved from simple to complex compositions, accordingly improving functions and performances,promoting the advancements of human civilization. In recent years, high-entropy alloys（HEAs） have attracted tremendous attention in various fields. With multiple principal components, they inherently possess unique microstructures and many impressive properties, such as high strength and hardness, excellent corrosion resistance, thermal stability, fatigue,fracture, and irradiation resistance, in terms of which they overwhelm the traditional alloys. All these properties have endowed HEAs with many promising potential applications.An in-depth understanding of the essence of HEAs is important to further developing numerous HEAs with better properties and performance in the future. In this paper, we review the recent development of HEAs, and summarize their preparation methods, composition design, phase formation and microstructures, various properties, and modeling and simulation calculations. In addition, the future trends and prospects of HEAs are put forward.

Research on Route Optimization of Battlefield Collection Equipment Based on Improved Ant Algorithm

Accurate battlefield collection plays a crucial role in the end of thewar. How to effectively improve the ability of accurate battlefield collection hasbecome a hot issue of research. However, the existing support force is limited. Tosolve the problem, an improved ant algorithm is applied to the path optimizationproblem of battlefield collection equipment. A model for solving the collectionpath optimization problem of battlefield collection vehicles was designed, andan example was used to simulate calculations. The final results show that thealgorithm is effective and practical,which improves the army’s ability to accuratelycollect equipment in the modern battlefield.