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Adhesive Contact of Elastic Solids with Self-Affine Fractal Rough Surfaces

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Acta Mechanica Solida Sinica 2024年第2期37卷 265-270页

作者： Xuan-Ming Liang Shi-Wen Chen Si-He wang zhen-Yuan Gong Jun feng Gang-feng wang Department of Engineering Mechanics SVL and MMMLXi’an Jiaotong UniversityXi’an710049China OPPO Mobile Telecommunications Corporation Ltd. Dongguan523860China

The elastic adhesive contact of self-affine fractal rough surfaces against a rigid flat is simulated using the finite element method. An array of nonlinear springs, of which the force-separation law obeys the Lennard–Jones potential, is introduced to account for the interfacial adhesion. For fractal rough surfaces, the interfacial interaction is generally attractive for large mean gaps, but turns repulsive as the gap continuously shrinks. The interfacial interactions at the turning point corresponding to the spontaneous contact are shown for various surfaces. For relatively smooth surfaces, the probability density distributions of repulsion and attraction are nearly symmetric. However, for rougher surfaces, the simulation results suggest a uniform distribution for attraction but a monotonously decreasing distribution with a long tail for repulsion. The pull-off force rises with increasing ratio of the work of adhesion to the equilibrium distance, whereas decreases for solids with a higher elastic modulus and a larger surface roughness. The current study will be helpful for understanding the adhesion of various types of rough solids.

关键词： Fractal rough surfaces Adhesion Contact mechanics Lennard-Jones potential

Microstructural Evolutions and Mechanical Properties of Energetic Al_(1) (TiZrNbTaMoCr)_(15) High-Entropy Alloys

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 620-632页

作者： Xuan-Hong Cai zhen-Hua wang Ben Niu Jin-feng Li Qing wang Show authors Key Laboratory of Materials Modification By Laser Ion and Electron Beams(Ministry of Education)Engineering Research Center of High Entropy Alloy Materials(Liaoning Province)School of Materials Science and EngineeringDalian University of TechnologyDalian116024China Institute of Materials China Academy of Engineering PhysicsMianyang621908China

The present study focuses on investigating the microstructural evolutions and mechanical properties of energetic Al_(1)(TiZrNbTaMoCr)_(15) refractory high-entropy alloys with the different heat treatments at low Al content state. It is found that even with a reduction in the Al content, the strength of these alloys remains unaffected at room temperature and high temperature, while the plasticity improves significantly. In particular, the coherent BCC/B_(2) microstructure with needle-like B_(2) nanoprecipitates dispersed into the BCC matrix is formed in 873 K-aged Al_(1)Ti_(6)Zr_(2)Nb_(3)Ta_(3)Mo_(0.5)Cr_(0.5) alloy. Therefore, this alloy exhibits the highest compression yield strength (σ_(YS) = 1333 and 717 MPa) at room temperature and 1073 K, respectively. After 973 K-aged, the coherent BCC/B_(2) microstructure underwent destabilization, and the B_(2) phase transforms into the brittle Zr5Al3 phase which then coarsens and dominates the microstructure of S3-AlTa_(3) alloy after 1073 K-aged. Moreover, these current alloys exhibit exceptionally high theoretical exothermic enthalpy (ΔH), surpassing 11606 J·g^(−1), which highlights their significant potential as innovative high-performance energetic structural materials.

关键词： Refractory high-entropy alloy Coherent microstructure Mechanical property Exothermic enthalpy

A Study on Molybdenite Electronic Structure

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Chemical Research in Chinese Universities 1995年第4期11卷 306-311页

作者： LONG Xiang-yun and wang feng-zhen (Dept .of Chem.,Central South University of Technology, Changshaha 410083) CENT S UNIV TECHNOL DEPT CHEMCHANGSHA 410083PEOPLES R CHINA

he present paper covers thedectronic structure of Molybdenite(MoS_2)with layer structure studied using tight-binding energy band structure calculation and localization molecular orbital CNDO/2 method,and the bonding c... 详细信息

关键词： Molybdenite Band structure Electronic structure

Induction of Apoptosis by L-NMMA,via FKHRL1/ROCK Pathway in Human Gastric Cancer Cells

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Biomedical and Environmental Sciences 2006年第4期19卷 285-291页

作者： YONG-ZHONG wang zhen-QING feng Department of Pathology Nanjing Medical University Nanjing 210029 Jiangsu China

Objective To investigate the apoptosis-inducing effect of endogenous nitric oxide （NO） suppression in gastric cancer cells and its mechanisms. Methods Apoptosis of gastric cancer cells was detected by flow cytometry. Expression of phosphorylated FKHRL1 （thr-32, ser-253） and FKHRL1 in gastric cancer cells was analyzed using Western blotting. Immunofluorescence assay was performed to localize the intracellular phosphorylated FKHRL1 （thr-32, ser-253） and FKHRL 1. Transfection of FKHRL1-HA wild type and mutant FKHRL1-HA T32A constructs was performed by lipofectamine plus reagent. NO generation was determined by Griess reaction. Results Gastric cancer cells were significantly apoptotic after treatment with NG-monomethyl-L-arginine （L-NMMA, a nitric oxide synthase inhibitor）, compared with the control （P〈0.01）. The apoptosis of gastric cancer cells induced by L-NMMA was dose-dependent and time-independent. However, the Z-DEVD-fmk, a caspase-3, 6, 7, 8, l0 inhibitor, did not prevent the apoptosis. The immunofluorescence assays showed that FKHRL1 protein was strongly expressed in the nucleu and p-FKHRL1 thr-32 protein was ：strongly expressed in the cytoplasm of SGC-7901 cells when endogenous nitric oxide generation was blocked by L-NMMA, but no change in FKHRL1 ser-253 phosphorylation. Nevertheless, ROCK protein was strongly expressed in p-FKHRL1 thr-32-positive SGC-7901 cells. The wortmannin, an inhibitor of phosphoinositol-3-OH kinase （PI3K）, did not block the phosphorylated FKHRL1 thr-32 protein induced by L-NMMA. However, Y-27632, a specific inhibitor of the protein kinase ROCK, significantly blocked apoptosis induced by phosphorylated FKHRL1 thr-32 （P〈0.01）, which was mediated by L-NMMA. A significant decrease in NO generation （P〈0.01） and a significant increase in apoptosis （P〈0.01） were observed when FKHRL1-HA wild-type cells were transfected, which caused increased FKHRL1 thr-32 phosphorylation. Conclusions L-NMMA triggers gastric carcinoma cell apoptosis, possibly

关键词： Gastric carcinoma Nitric oxide FKHRL1 Apoptosis Signaling

Effect of microalloying on wettability and interface characteristics of Zr-based bulk metallic glasses with W substrate

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China Foundry 2024年第4期21卷 352-359页

作者： zhen Zhang Lin-na feng Jin-he wang zheng-kun Li Hua-meng Fu Hong Li zheng-wang Zhu Hai-feng Zhang School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Metallurgy Northeastern UniversityShenyang 110004China

The infiltration casting method is widely employed for the preparation of ex-situ composite ***,the production of composite materials using this method must necessitates a comprehensive understanding of the wettability and interface characteristics between the reinforcing phase and the bulk metallic glasses(BMGs).This work optimized the composition of Zr-based BMGs through microalloying methods,resulting in a new set of Zr-based BMGs with excellent glass-forming *** experiments between the Zr-based BMGs melts and W substrates were conducted using the traditional sessile drop method,and the interfaces were characterized utilizing a scanning electron microscope(SEM)equipped with energy dispersive X-ray spectroscopy(EDS).The work demonstrates that the microalloying method substantially enhances the wettability of the Zr-based BMGs ***,the incorporation of Nb element impedes the formation of W-Zr phases,but the introduction of Nb element does not alter the extent of interdiffusion between the constituent elements of the amorphous matrix and W element,indicating that the influence of Nb element on the diffusion of individual elements is minute.

关键词： Zr-based BMGs infiltration casting method wettability interface characteristics W-Zr phases

Si/TiO2 carbon fiber core encapsulated in hierarchical multiple MXene@Co-MoS2 shells for constructing a free-standing anode of lithium storage

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Rare Metals 2024年第9期43卷 4222-4233页

作者： Xian-ping Du Ying Huang Jia-ming wang zhen-he feng Xu Sun MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions School of Chemistry and Chemical Engineering Northwestern Polytechnical University Shanghai Institute of Space Power-Sources Ningbo Institute of Northwestern Polytechnical University

Silicon-based（Si-based） materials offer more possibilities for generating new portable electronic devices due to their high specific capacities. However, their inferior electrical conductivity and volume expansion during cycling seriously limit their development. The optimum solution is to select specific materials to establish an exceptionally conductive and volume buffer structure,which can assist Si materials in developing their excellent lithium storage properties. In this study, Si particles were confined in TiO2carbon fibers（TiO2CFs） via electrospinning, after which they were encapsulated with MXene and Co-MoS2（CMS） nanosheets to fabricate hierarchical ST-2@MXene@CMS films. TiO2CF, MXene and CMS were employed to establish a coherent conductive network with one-, two-and three-dimensional electronic pathways to permit the unimpeded flow of electrons inside the electrode material. TiO2CF, MXene and CMS acted precisely as multilayered buffers to ameliorate the volume change of Si particles during cycling. In addition, the CMS nanosheets were involved in lithium storage, contributing to the final electrochemical performance. Ultimately, the ST-2@MXene@CMS films served as free-standing electrodes, avoiding the impact of inactive interfaces on the electrochemical performance and fulfilling the lightweight requirement for new energy storage devices.

关键词： Co-MoS2 nanosheets Hierarchical structure Lithium-ion batteries MXene Si particles

Removal of pathogenic indicator microorganisms during partial nitrification:the role of free nitrous acid

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Frontiers of Environmental Science & Engineering 2024年第3期18卷 93-102页

作者： Jiaojiao Xu Xiaotian Chen Rui Tang Jingwei feng Shoujun Yuan Wei wang zhen-Hu Hu Anhui Engineering Laboratory of Rural Water Environment and Resource School of Civil EngineeringHefei University of TechnologyHefei 230009China Hefei 168 High School Hefei 230025China Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power Shanghai University of Electric PowerShanghai 200090China

Digested wastewater contains pathogenic microorganisms and high ammonia concentrations,which can pose a potential risk to public *** removal of pathogens and nitrogen is crucial for the post-treatment of digested *** nitrification-anammox is an energy-saving nitrogen removal *** nitrous acid(FNA),an intermediate product of partial nitrification,has the potential to inactivate ***,the efficiency and mechanisms of FNA-related inactivation in pathogens during partial nitrification remains *** this study,Enterococcus and Escherichia coli(***)were selected to investigate the efficiency and mechanisms of FNA-related inactivation in partial nitrification *** results revealed that 83%±13%and 59%±27%of *** and Enterococcus were removed,respectively,in partial nitrification process at FNA concentrations of 0.023−0.028 mg/*** the concentration of FNA increased from 0 to 0.5 mg/L,the inactivation efficiencies of *** and Enterococcus increased from 0 to 99.9%and 89.9%,*** exhibited a higher resistance to FNA attack compared to ***.3D-laser scanning microscopy(3D-LSM)and scanning electron microscopy(SEM)revealed that FNA exposure caused the surface collapse of *** and Enterococcus,as well as visible pore formation on the surface of *** cells.4',6-Diamidino-2-phenylindole dihydrochloride n-hydrate(DAPI)/propidium iodide(PI)and biomolecule leakage confirmed that inactivation of *** and Enterococcus occurred due to breakdown of cell walls and cell *** findings indicate that partial nitrification process can be used for the removal of residual pathogenic microorganisms.

关键词： Partial nitrification Free nitrous acid Pathogenic indicator microorganism Inactivation Cell structure

Number of Solitons Emerged in the Initial Profile of Shallow Water Using Convolutional Neural Networks

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Journal of Systems Science & Complexity 2024年第2期37卷 463-479页

作者： wang zhen CUI Shikun School of Mathematical Sciences Dalian University of TechnologyDalian 116024China School of Mathematical Sciences Beihang UniversityBeijing 100191China

The soliton resolution conjecture proposes that the initial value problem can evolve into a dispersion part and a soliton ***,the problem of determining the number of solitons that form in a given initial profile remains unsolved,except for a few specific *** this paper,the authors use the deep learning method to predict the number of solitons in a given initial value of the Korteweg-de Vries(KdV)*** leveraging the analytical relationship between Asech^(2)(x)initial values and the number of solitons,the authors train a Convolutional Neural Network(CNN)that can accurately identify the soliton count from spatio-temporal *** trained neural network is capable of predicting the number of solitons with other given initial values without any additional *** extensive calculations,the authors demonstrate the effectiveness and high performance of the proposed method.

关键词： Convolutional neural network deep learning method KdV equation soliton

Substantial increase of heat-induced labor and economic loss in China under rapid economic and environmental temperature growth

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Advances in Climate Change Research 2024年第4期15卷 708-716页

作者： Bo-Wen CHU Jian-feng LUO Ke-Xin wang zhen-Cheng XING Hai-Kun wang Joint International Research Laboratory of Atmospheric and Earth System Sciences School of Atmospheric SciencesNanjing UniversityNanjing 210023China Collaborative Innovation Center of Climate Change Jiangsu ProvinceNanjing 210023China Frontiers Science Center for Critical Earth Material Cycling Nanjing UniversityNanjing 210023China Nanjin-Helski Insiute in Amosperc and Earth System Sciences Nanjing UniversityNanjing 210023China

Exposure to heat stress causes diminished work performance and leads to economic *** the last two decades,China has experienced both rapid economic development and environmental warming;however,the spatiotemporal variations of association between environmental heat and labor loss have been rarely investigated behind this double ***,we evaluated the variation in China's heat-induced labor productivity loss and related economic cost from 2001 to 2019 and investigated the effect of economic development and regional *** found that decline in labor productivity because of heat stress increased significantly(p<0.05 for heavy-intensity work),and the corresponding economic loss also exhibited a drastic increase by 6-to *** relative economic loss showed a slight but nonsignificant increase with an average value of 0.54%of the annual total *** the sub-regional and sectoral level,adverse effects were more prominent in the southeast region,and the secondary industry sectors,such as construction and manufacturing,contributed to larger proportions of economic *** transformation of industrial structure made economic sectors more vulnerable to heat exposure,and increasingly preventive effects of air-conditioning use were noted on economic damage due to heat-induced productivity decline(36.0%relative economic benefits in 2019 compared to 9.7%in 2001).Our findings could provide a deep insight into heat burden on occupational health and heat adaptation strategies regionally under climate change,especially in developing areas with higher temperature and humidity environment.

关键词： Heat stress Labor loss Wet bulb globe temperature China Economic impact