摘要：In order to overcome the limitations of traditional microperforated plate with narrow sound absorption bandwidth and a single structure,two multi-cavity composite sound-absorbing materials were designed based on the shape of monoclinic crystals:uniaxial oblique structure(UOS)and biaxial oblique structure(BOS).Through finite element simulation and experimental research,the theoretical models of UOS and BOS were verified,and their sound absorption mechanisms were *** the same time,the influence of multi-cavity composites on sound absorption performance was analyzed based on the theoretical model,and the influence of structural parameters on sound absorption performance was *** research results show that,in the range of 100-2000 Hz,UOS has three sound absorption peaks and BOS has five sound absorption *** frequency range of the half-absorption bandwidth(α>0.5)of UOS and BOS increases by 242% and 229%,*** with traditional microperforated sound-absorbing structures,the series and parallel hybrid methods significantly increase the sound-absorbing bandwidth of the sound-absorbing *** research has guiding significance for noise control and has broad application prospects in the fields of transportation,construction,and mechanical design.

摘要：本研究旨在运用网络药理学分析方法与分子对接技术研究灭幽汤异病同治慢性萎缩性胃炎和胃溃疡的作用机制。运用TCMSP和BATMAN-TCM数据库筛选出灭幽汤的有效成分,Genecards、OMIM、Disgenet、Drugbank数据库筛选出慢性萎缩性胃炎和胃溃疡的相关靶点;采用Cytoscape 3.9.1软件绘制“方剂-药物-活性成分-核心靶点-疾病”的网络拓扑图;采用STRING数据库构建蛋白互作网络;运用David数据库对核心靶点进行GO富集分析及KEGG通路分析;采用Auto Dock4软件进行分子对接预测药物与疾病靶点的结合性,通过Py MOL2.2软件实现对接结果可视化。结果得到灭幽汤有效成分73个, CAG相关靶点761个, GU相关靶点640个,通过Venny图取交集后得到54个靶点, Cytoscape筛选后得核心靶点37个。分子对接结果显示,TP53、IL6等5种蛋白与木犀草素(luteolin)、金合欢素(acacetin)、柚皮素(naringenin)、黄芩苷(baicalein)、汉黄芩素(wogonin)有较好的结合活性;KEGG富集分析主要得到癌症通路、脂质与动脉粥样硬化、PI3K-Akt信号通路、MAPK信号通路、IL-17信号通路、AGE-RAGE信号通路等。研究表明,灭幽汤异病同治慢性萎缩性胃炎和胃溃疡具有多成分、多靶点及多通路的特性,其主要成分与活性分子靶点结合,通过调控癌症、脂质与动脉粥样硬化等信号通路实现“同治”CAG和GU的目的。为传统中医药的“异病同治”理论提供了现代医学证据,并且为今后的新药研发与实验设计指明了方向。

摘要：设S=(P,B)是一个非平凡的3-(v,7,λ)设计且满足λ≥2.本文证明:如果G是S上的一个区传递自同构群,则G是仿射型或者几乎单型的点本原群.此外,我们还考虑G的基柱为交错群A_n的一种有限几乎单群的情形.

摘要：Aimed at the uncertain characteristics of discrete logistics network design,an interval hierarchical triangular uncertain OD demand model based on interval demand and network flow is *** consideration of the system profit,the uncertain demand of logistics network is measured by interval variables and interval parameters,and an interval planning model of discrete logistics network is *** risk coefficient and maximum constrained deviation are defined to realize the certain transformation of the *** integrating interval algorithm and genetic algorithm,an interval hierarchical optimal genetic algorithm is proposed to solve the *** is shown by a tested example that in the same scenario condition an interval solution[3275.3,3 603.7]can be obtained by the model and algorithm which is obviously better than the single precise optimal solution by stochastic or fuzzy algorithm,so it can be reflected that the model and algorithm have more stronger operability and the solution result has superiority to scenario decision.

摘要：First-principle calculation was used to investigate the magnetic properties, electronic structure and bonding mechanism of FeF2. By calculating the lattice parameters and magnetic moment as a function of effective interaction parameter （Ueff）, it is found that the optimum value of Uefr is equal to 4 eV, the magnetic moment is 3.752 μB and the value of c/a is 0.704, which are in good agreement with the experiment results. Simultaneously, on the basis of GGA＋U method, the electronic structure and bonding mechanism of FeF2 were investigated by the analysis of electron localization function, Bader charge and total charge density. The results show that the bonding behavior between Fe and F atoms is a combination of ionic and covalent bond.

摘要：Porous Ni3Al intermetallics were fabricated by elemental powder reactive synthesis method, using carbamide powders as space holders. Corrosion behavior of porous Ni3Al intermetallics was investigated in a 6 mol/L KOH solution using electrochemical methods and immersion test. Effect of porous structures on the corrosion behavior of the porous Ni3Al intermetallics was studied. The results indicate that the porous Ni3Al intermetallics with higher porosities suffer more serious corrosion than the ones with lower porosities because the complicated interconnected porous structures and the large true surface areas exist in the samples with a higher porosity. But the corrosion rates of the porous Ni3Al intermetallics are not proportional to the true surface areas. The reason is that the pore size, pore size distribution and pore shape of the porous Ni3Al intermetallics change with the increasing porosity. All the porous Ni3Al intermetallics with different porosities exhibit excellent corrosion resistance in a strong alkali solution.

摘要：The interfacial heat transfer coefficient between hot profile surface and cooling water was determined by using inverse heat conduction model combined with end quenching experiment. Then, a Deform-3 D thermo-mechanical coupling model for simulating the on-line water quenching of extruded profile with unequal and large thicknesses was developed. The temperature field, residual stress field and distortion of profile during quenching were investigated systematically. The results show that heat transfer coefficient increases as water flow rate increases. The peak heat transfer coefficient with higher water flow rates appears at lower interface temperatures. The temperature distribution across the cross-section of profile during quenching is severe nonuniform and the maximum temperature difference is 300 ℃ at quenching time of 3.49 s. The temperature difference through the thickness of different parts of profile first increases sharply to a maximum value, and then gradually decreases. The temperature gradient increases obviously with the increase of thickness of parts. After quenching, there exist large residual stresses on the inner side of joints of profile and the two ends of part with thickness of 10 mm. The profile presents a twisting-type distortion across the cross-section under non-uniform cooling and the maximum twisting angle during quenching is 2.78°.

摘要：In order to study the application of gyratory compaction molding method in emulsified asphalt cold recycled mixture and optimize the relevant technical parameters, the study was carried out according to splitting strength, stability and water stability test;the design of the experiment involved changing gyration number, emulsified asphalt and water content, molded specimen temperature and other factors to analyze the volume parameters, mechanical properties and water stability. The results show that both the maximum dry density and dry and wet splitting strength ratio(DWSSR) of emulsified asphalt cold reclaimed mixture are improved by the rotary compacting method, while the porosity and the optimal dosage of water are reduced. Furthermore, with the increase of compaction times, the porosity and splitting strength index both change exponentially. DWSSR and porosity are consistent with quadratic functions. The use of gyratory compaction for 70 times at 25 °C and the optimum dosage of emulsified asphalt can be determined based on the splitting strength ratio. The high-temperature stability and water damage resistance of the pavement can be improved by the use of rotary compacting method effectively, and the early strength and road performance are higher than the regulatory requirements.

摘要：6061 aluminum alloy T-joints were welded by double-pulsed MIG welding process. Then, the post-weld heat treatment was performed on the welded T-joints. The weld microstructure under different aging temperature and time was investigated by transmission electron microscopy and scanning electron microscopy. The mechanical properties were examined by hardness test and tensile test. The results showed that the micro-hardness was sensitive to heat treatment temperature and time. Increasing temperature was beneficial to the shortening of peak aging time. There were a large number of dislocations and few precipitates in the welded joints. With the increase of post-weld heat treatment temperature and time, the density of dislocation decreased. Meanwhile, the strengthening phase precipitated and grew up gradually. When the post-weld heat treatment temperature increased up to 200℃, large Q' phases were observed. And they were responsible for the peak value of the micro-hardness in the welded joints.

摘要：High-entropy alloys(HEAs)have been widely studied due to their unconventional compositions and unique physicochemical properties for various ***,for the first time,we propose a surface strain strategy to tune the electrocatalytic activity of HEAs for methanol oxidation reaction(MOR).High-resolution aberration-corrected scanning transmission electron microscopy(STEM)and elemental mapping demonstrate both uniform atomic dispersion and the formation of a face-centered cubic(FCC)crystalline structure in Pt Fe Co Ni Cu *** HEAs obtained by heat treatment at 700℃(HEA-700)exhibit 0.94%compressive strain compared with that obtained at 400℃(HEA-400).As expected,the specific activity and mass activity of HEA-700 is higher than that of HEA-400 and most of the state-of-the-art *** enhanced MOR activity can be attributed to a shorter Pt–Pt bond distance in HEA-700 resulting from compressive *** nonprecious metal atoms in the core could generate compressive strain and down shift d-band centers via electron transfer to surface Pt *** work presents a new perspective for the design of high-performance HEAs electrocatalysts.