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Tribological properties of sputtered tungsten and tungsten nitride thin films

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Science China mathematics 2001年第S1期44卷 242-247页

作者： Wong K.m. Shen y.G. Wong P.L. Department of manufacturing Engineering and Engineering management City University of Hong KongTat Chee AvenueKowloonHong KongChina

The surface roughness, hardness and tribological properties of tungsten (W) and tung- sten nitride (WN_x) thin films prepared by dc magnetron sputtering and reactive magnetron sputter- ing in Ar-N_2 gas mixtures have been studied using atomic force microscopy (AFm), nanoindenta- tion measurements and ball-on-disc wear testing. A pronounced surface roughness was observed only for films under compressive strains. The surface was flat under tension but rough under com- pression. Similar hardness with value about 20 GPa were observed in the W and WN_x (x=0.3) films. This is thought to be due to the fact the grains are restricted to a very small size in the coat- ings. The higher coefficients of friction (0.4 for W and 0.9 for WN_(0.3)) suggest that WN_(0.3) is not the optimum phase. Finally, discussions are made with tribological test results.

关键词： atomic force microscopy ball-on-disc wear testing nanoindentation toughen tungsten nitride

Thermal dependence of the properties of cubic boron nitride crystal

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Natural Science 2011年第2期3卷 154-164页

作者： Zainelabideen y. mijbil mudar A. Abdulsattar Ahmed m. Abdul-Lettif 不详

Lattice constant, total energy, cohesive energy, bulk modulus, speed of sound (υ), plasmon energy (Epl), valence charge distribution and energy bands of cubic boron nitride crystal have been calculated and studied as a function of temperature using self-consistent field tight binding method with complete neglect of differential overlap version 2 using 8-atom large unit cell approach. Our results illustrate that the increase of temperature leads to an increase of lattice constant, cohesive energy, and valence charge distribution at the atoms, whereas a decrease is obtained for bulk modulus, energy band widths, valence charge distribution in the intratomic distance, speed of sound, and the plasmon energy. The comparison with experimental and other theoretical results has showed an excellent agreement for the lattice constant, bulk modulus, cohesive energy, speed of sound, plasmon energy value and the valence band, whereas remarkable differences in charge distribution values, and the band gap are found. These differences are common in the results that depend on this type of calculation. Values for conduction band and speed of sound have not been found for comparison. Our relation for Epl-T fails but the υ-T relation is successful.

关键词： Electronic Structure Temperature Dependence Boron Nitride

STUDy OF DyNAmIC RECRySTALLIZATION OF LOW CARBON STEEL IN THIN SLAB CONTINUOUS ROLLING PROCESS

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Acta metallurgica Sinica(English Letters) 2006年第4期19卷 265-270页

作者： X.K. Liang X.J. Sun Q.y. Liu H. Dong State Key Laboratory of Advanced Steel Processes and Products Central Iron and Steel Research Institute Beijing 100081 China

Combined with the technological characteristics of thin slab continuous rolling process （TSCR）, dynamic recrystallization of an extremely coarse austenite of low carbon steel is studied by Thermecmaster-Z hot simulator. By the analysis of true stress-strain curves and the observation of microstructures at different deformation stages, the critical stress and critical strain are determined under different deformation conditions. The effect of Z parameter on dynamic recrystallization of coarse austenite is studied. The microstructure evolution in real production is also discussed.

关键词： TSCR (thin slab continuous rolling process) coarse austenite dynamic recrystallization

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美国疼痛医学专科医师培训

中国疼痛医学杂志 2013年第4期19卷 199-200,198页

作者： m.y.DuBois 倪兵胡永生

概述在过去的30年间,疼痛医学逐渐成为最活跃的一个领域。最近一份来自医学院的报告称,在美国受疼痛困扰的人数高达1亿,尽管每年医疗费用约为5600—6350亿美元,但患者仍然得不到很好的治疗。已知的一个原因就是疼痛医学并未被官方承认,... 详细信息

概述在过去的30年间,疼痛医学逐渐成为最活跃的一个领域。最近一份来自医学院的报告称,在美国受疼痛困扰的人数高达1亿,尽管每年医疗费用约为5600—6350亿美元,但患者仍然得不到很好的治疗。已知的一个原因就是疼痛医学并未被官方承认,也未发展为一项医学专科,而只是被当作一系列零散的亚专科,因而患者得不到整体的治疗。被美国医学专科学会（ABmS）认证为疼痛医学,

关键词：专科医师培训疼痛医学美国医学专科医疗费用医学院治疗患者

Novel model of thermo-magneto-viscoelastic medium with variable thermal conductivity under effect of gravity

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Applied mathematics and mechanics(English Edition) 2020年第5期41卷 819-832页

作者： S.m.SAID Department of mathematics Faculty of ScienceZagazig UniversityZagazig 44519Egypt Department of mathematics Faculty of Science and ArtsQassim UniversityBuridah 51931Al-mithnabKingdom of Saudi Arabia

The basic equations for a homogeneous and isotropic thermo-magnetoviscoelastic medium are formulated based on three different theories, i.e., the GreenLindsay(G-L) theory, the coupled(CD) theory, and the Lord-Shulman(L-S) theory. The variable thermal conductivity is considered as a linear function of the temperature. Using suitable non-dimensional variables, these basic equations are solved via the eigenvalue approach. The medium is initially assumed to be stress-free and subject to a thermal *** numerical results reveal that the viscosity, the two-temperature parameter, the gravity term, and the magnetic field significantly influence the distribution of the physical quantities of the thermoelastic medium.

关键词： eigenvalue approach variable thermal conductivity thermo-viscoelastic gravity field

Twinning mechanism in TWIP Steel: From Single Crystalline micro-pillar to Bulk Sample

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Twinning Mechanism in TWIP Steel: From Single Crystalline Mi...

Divergence and flutter instability of magneto-thermo-elastic C-BN hetero-nanotubes conveying fluid

第十届中国钢铁年会暨第六届宝钢学术年会

作者： Huang m.X. Liang Z.y. Department of mechanical Engineering The University of Hong Kong

Twinning-induced plasticity（TWIP） steels have excellent combination of strength（1000 mPa） and ductility（60%） and are potential lightweight materials for automotive applications. The excellent mechanical properties of TWIP steels are due to the formation of intensive deformation twins during deformation. Understanding the twinning mechanisms in TWIP steels is essential for the successful application of TWIP steels in automotive industry. The first part of this work is to employ sub-micon and micron-sized single crystalline pillars to investigate the nucleation and growth mechanism of deformation twins. It is found that the nucleation and growth of deformation twins are due to emission and glide of successive partial dislocations. The twin thickness can range from nanometres to micrometres. A physical model is proposed to simulate the nucleation and growth of deformation twins and the model predictions agree well with experimental observations. The second part of this work investigates the effect of high strain rates on the deformation mechanism of bulk samples. By synchrotron X-ray diffraction experiments, the present work demonstrates that a higher strain rate leads to a lower dislocation density and a lower twinning probability. This unexpected suppression of dislocation and twin evolution have been attributed to the temperature increase due to dissipative heating at high strain rate deformation. A physically-based model has been proposed to simulate the evolution of dislocation and twin densities and to model the stress-strain relation. The modelling results agree well experimental findings.

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Acta mechanica Sinica 2020年第2期36卷 381-396页

作者： Hamid m.Sedighi mechanical Engineering Department Faculty of EngineeringShahid Chamran University of AhvazAhvaz 61357-43337Iran Drilling Center of Excellence and Research Center Shahid Chamran University of AhvazAhvaz 61357-43337Iran

On the basis of finite element analysis,an eigenvalue problem is performed to examine the vibrational characteristics of a hetero-nanotube made of carbon(C)and boron nitride(BN)nanotubes in magnetic and thermal *** incorporating the assumption of nonlocal elasticity theory,the size-dependent behavior of the considered structure is also taken into *** obtained results demonstrate that the onset of the divergence and flutter instabilities may be postponed by exploiting a hetero-nanotube rather than a uniform one composed of carbon ***,it is exhibited that,in the presence of fluid flow,the mode shape configuration of nanotubes may be different from those of classical modes and therefore the later one should not be utilized in the dynamic analysis of fluid-conveying ***,it is shown that,as the temperature decreases,the natural frequencies of the system decrease in high temperature conditions and increase for the case of room temperature.

关键词： Hetero-nanotube Fluid-conveying magnetic flow Nonlocal elasticity Thermal environment

3D human nonalcoholic hepatic steatosis and fibrosis models

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Bio-Design and manufacturing 2021年第2期4卷 157-170页

作者： Sushila maharjan Diana Bonilla Princy Sindurakar Hongbin Li Wanlu Li Sergio Duarte Ali Zarrinpar y.Shrike Zhang Division of Engineering in medicine Department of MedicineBrigham and Women’s HospitalHarvard Medical School65 Landsdowne StCambridgeMA 02139USA Department of Biology College of the Holy CrossWorcesterMA 01610USA Department of Surgery University of Florida1600 SW Archer RdGainesvilleFL 32610USA Department of Biomedical Engineering University of FloridaGainesvilleFL 32610USA Department of Biochemistry and molecular Biology University of FloridaGainesvilleFL 32610USA

This study presents a simple and robust three-dimensional human hepatic tissue model to emulate steatotic and fibrotic conditions and provide an in vitro model for drug testing and mechanistic *** a photolithographic biofabrication method with a photomask featuring hexagonal units,liver cells,including a human hepatic cell line(HepG2-C3A)and a human hepatic stellate cell line(LX-2)were embedded in gelatin methacryloyl *** steatosis was induced by supraphysiological concentration of free fatty acids;hepatic fibrosis was induced by transforming growth factor-β*** of steatosis was confirmed by Oil Red O and BODIPy staining and was inhibited with toyocamycin and obeticholic *** of fibrosis was confirmed by immunostaining for collagen type I and alpha smooth muscle actin and inhibited by rapamycin and curcumin *** model was further preliminarily validated using primary human hepatocytes in a similar *** constructs provide a viable,biologically relevant,and higher throughput model of hepatic steatosis and fibrosis and may facilitate the study of the mechanisms of disease and testing of liver-directed drugs.

关键词： Nonalcoholic fatty liver disease(NAFLD) Gelatin methacryloyl(GelmA) Photocrosslinking Steatosis

Leachate Control Technology Using H-Jointed Steel Pipe Sheet Piles with H-H Joints at Coastal Landfills

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Journal of Environmental Science and Engineering 2010年第11期4卷 65-70页

作者： S. Inazumi m. Kimura y. Nishiyama K. Kojima Department of Urban management Kyoto University Kyoto 6158540 Japan Department of Civil and Earth Resources Engineering Kyoto University Kyoto 6158540 Japan Data-too Co. Ltd. Tokyo 1050012 Japan Otowa Co. Ltd. Numazu 4100308 Japan

H-H joint of ＂H-jointed SPSP with H-H joint＂, which is made up of interlocking two H-steel sections of different sizes, is the one of SPSP＇s joint to improve the hydraulic conductivity. ＂H-H jointed SPSP with H-H joint＂ is expected to be applied to a vertical cutoff wall in coastal landfill sites. In H-jointed SPSP with H-H joint, the H-joint is completely imperviousness. H-H joint, however, is pervious at interlocked state because a gap of 8 to 11 mm is left between the interlocking flanges, therefore, a water interception treatment must be conducted to seal the gap. The water shielding treatment of H-H joint is executed by coating the gaps with a water-swelling sheet of paint before its installation. Then, hollow space is generated in H-H joint after treating by water-swelling sheet, and that space can be used effectively. This paper proposes leachate control technologies using H-H joint interior space of SPSP cutoff walls. The possibility of those technologies and hydraulic conductivity of H-jointed SPSP with H-H joints are demonstrated by conducting the hydraulic conductivity test.

关键词： H-H joint H-jointed steel pipe sheet pile hydraulic conductivity.