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高强度轴承钢滚动接触疲劳的Ⅱ型裂纹扩展驱动力

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河南科技大学学报(自然科学版) 1988年第2期 29-40页

作者：陈菁 Hahn G t Rubin C A Bhargava v

本文探讨了滚动接触产生的残余应力对Ⅱ型应力强度因子幅度(ΔK)的影响,此ΔK是指承受重复滚动接触轴承圈的次表层裂纹扩展驱动力。对于高强度轴承钢,分别在短寿命(N=2—10~7),产生较小周向残余应力的情况下及在长寿命(N=10~8—10)产生... 详细信息

本文探讨了滚动接触产生的残余应力对Ⅱ型应力强度因子幅度(ΔK)的影响,此ΔK是指承受重复滚动接触轴承圈的次表层裂纹扩展驱动力。对于高强度轴承钢,分别在短寿命(N=2—10~7),产生较小周向残余应力的情况下及在长寿命(N=10~8—10)产生较大周向残余应力的情况下进行了计算。在计算时还把赫芝应力、裂纹相对深度、裂纹倾斜角度及裂纹表面间的摩擦力等作为变量。在下列前提下进行计算:二维的、重复的、无摩擦的纯滚动接触;符合线弹性断裂力学条件;存在的是平面的、小的次表面裂纹。最后将计算结果与实际观察的裂纹生长剥落情况对比。研究结果表明:除裂纹倾角极小的特殊情况外,一般说在较长寿命下所形成较大的残余压应力能明显地使次表层粗糙裂纹的扩展驱动力(ΔK)减小。

关键词：裂纹实际观察高倍缺陷(金属) 应力强度因子力学因子残余应力残余内应力滚动接触疲劳轴承钢周向驱动力相对深度纯滚动接触线弹性断裂力学脆性断裂力学高强度

Role of stenting in the palliation of gastroesophageal junction cancer: A brief review

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World Journal of Gastrointestinal Surgery 2014年第3期6卷 38-41页

作者： theodoros E Pavlidis Efstathios t Pavlidis Second Surgical Propedeutic Department Medical SchoolAristotle University of ThessalonikiHippocration Hospital

Gastroesophageal junction cancer has an increasing in-cidence in western countries. It is inoperable when firstmanifested in more than 50% of cases. So, palliationis the only therapeutic option for the advanced diseaseto relieve dysphagia and its consequences in weakenedpatients with an estimated mean survival under 6 *** article has tried to identify trends focusing on cur-rent information about the best palliative treatment,with an emphasis on the role of stenting. Self-expand-ing stent placement, either metal or plastic, is the mainmanagement option. However, this anatomical loca-tion creates some particular problems for stent safetyand effectiveness which may be overcome by properlydesigned novel stents. the stents ensure a good qual-ity of life and must be preferred over other alterna-tive methods of loco-regional modalities, i.e., externalradiation, laser thermal or photodynamic therapy. Al-though stent placement is generally a simple, safe andeffective method, there are sometimes complications,increasing the morbidity and mortality rate. Bypassoperative procedures have now been abandoned as afirst choice. the stomach instead of the colon must beused for a bypass operation when it is needed. Chemo-therapy, despite the toxicity, and intraluminal radiation(brachytherapy) have a well-defined role.

关键词： Gastroesophageal junction cancer Palliative therapy Stent placement Dysphagia relief Esophageal carcinoma Gastric carcinoma

Demonstrations of Neutron Resonance Spin Echo for Pulsed Source

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Demonstrations of Neutron Resonance Spin Echo for Pulsed Sou...

Low field microwave absorption and magnetization process in CoFeNi electroplated wires

作者： m.Kitaguchi m.Hino Y.Kawabata S.tasaki R.maruyama t.Ebisawa JAEA

INtRODUCtION:Neutron spin echo(NSE) is one of the techniques with the highest energy resolution for quasi-elastic scattering by measuring rotation of the neutron *** neutron resonance spin echo(NRSE),two resonance spin flippers(RSFs) replace a homogeneous static magnetic field for spin precession in the conventional *** RSF,which flips the spin of a neutron by exchanging energy between the neutron and an oscillating magnetic field,gives the difference of wavenumber between up- and down-spin components of the neutron.

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Chinese Physics B 2008年第4期17卷 1430-1435页

作者： H.García-miquel G.v.Kurlyandskay E.t.S.I.telecomunicación Dpto.Ing.ElectrónicaUniversidad Politcnica de ValenciaCamino de Vera s/nValencia 46022Spain Universidad del País vasco UPv-EHU Dept.Electricidad y ElectrónicaApdo.644Bilbao 48080Spain Department of Physics Ferromagnetic Resonance GroupUniversity of MarylandCollege ParkMaryland 20742-4111USA

Ferromagnetic resonance （FmR）, Ferromagnetic antirresonance （FmAR） and low field magnetoimpedance （mI） are the characteristic features of high frequency losses in applied fields. While some results on FmR and FmAR in CoFeNi electroplated wires were reported earlier, here we present microwave absorption in CuBe wires electroplated by 1 μm FeCoNi magnetic layer at very low fields. these data are comparatively analysed together with longitudinal hysteresis loops in order to reveal the correlation between power absorption and magnetization processes. microwave studies are made by using the cavity perturbation method at 9.65 GHz for a DC field parallel to the sample axis, and with microwave magnetic field hrf parallel or perpendicular to the wire axis. two peaks have been observed in all samples, one is due to FmR, and the other is, at very low fields, related to mI. the mI peaks represent minima in power absorption. By comparing with the hysteresis loop we remark the close correspondence between the mI phenomena in the axial mode and the concomitant magnetization process.

关键词： microwave absorption magnetoimpedance electroplated wires

Quantum dynamics of charge transfer on the one-dimensional lattice:Wave packet spreading and recurrence

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Chinese Physics B 2016年第1期25卷 817-830页

作者： v N Likhachev O I Shevaleevskii G A vinogradov Emanuel Institute of Biochemical Physics Russian Academy of Sciences

the wave function temporal evolution on the one-dimensional （ID） lattice is considered in the tight-binding approxi- mation. the lattice consists of N equal sites and one impurity site （donor）. the donor differs from other lattice sites by the on-site electron energy E and the intersite coupling C. the moving wave packet is formed from the wave function initially localized on the donor. the exact solution for the wave packet velocity and the shape is derived at different values E and C. the velocity has the maximal possible group velocity v = 2. the wave packet width grows with time -t1/3 and its amplitude decreases ,- t-1/3. the wave packet reflects multiply from the lattice ends. Analytical expressions for the wave packet front propagation and recurrence are in good agreement with numeric simulations.

关键词： quantum dynamics tight-binding approximation charge transport

CO加氢选择性合成C_2-含氧化物的Rh/v/SiO_2催化剂的反应特性

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煤化工 1990年第1期18卷 26-32页

作者：罗洪原 A.G.t.m.Bastein v.Ponec 林励吾中国科学院大连化学物理研究所 Gorlaeus Laboratories Leidein University

本研究从RhCl_3·3H_2O和vOCl_2·5H_2O及SiO_2出发制备了对C_2-含氧化物的生成具有良好活性和选择性的Rh/v/SiO_2催化剂。当v/Rh=0.5～1(原子比),还原温度在250～300℃时催化剂的活性和选择性都较佳。适当地提高反应的压力、温度和空速... 详细信息

本研究从RhCl_3·3H_2O和vOCl_2·5H_2O及SiO_2出发制备了对C_2-含氧化物的生成具有良好活性和选择性的Rh/v/SiO_2催化剂。当v/Rh=0.5～1(原子比),还原温度在250～300℃时催化剂的活性和选择性都较佳。适当地提高反应的压力、温度和空速,可在选择性基本不变的条件下,使C_2含氧化物的生成速率大大提高。在6大气压、230℃和24000毫升/时·克催化剂下可获得C_2-含氧化物生成选择性达80％,生成速率达0.9克/时·克催化剂C_2-含氧化物的良好结果。

关键词：一氧化碳加氢合成含氧化合物 C2

measurements of Plasma Electron temperature Utilizing magnesium Lines Appeared in Laser Produced Aluminum Plasma in Air

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Optics and Photonics Journal 2012年第4期2卷 278-285页

作者： Ashraf m. El Sherbini Abdel Aziz S. Al Aamer Ahmed t. Hassan tharwat m. El Sherbini Department of Physics Collage of Science Al Imam Muhammad Ibn Saud Islamic University (AIMSIU) Al Riyadh KSA Laboratory of lasers and New materials (LLNm) Department of physics Faculty of Science Cairo University Giza Egypt

We have utilized the relative intensity of magnesium lines originated from the mg I at 285.2 nm and mg II at 280.27, 279.55 nm to measure the plasma electron temperature. the plasma was produced via interaction of Nd:YAG laser with solid aluminum target contains traces of magnesium. the magnesium lines were found to suffer from optical thickness which manifests itself on the form of scattered points around the Saha-Boltzmann line. We have utilized a simple method used for rapid calculation to the amount of absorption to these lines via comparison of the electron densities as deduced from magnesium lines to that evaluated from the optically thin hydrogen Hα line at 656.27 nm appeared in the same spectra under the same condition. A correction to the magnesium spectral lines intensities was carried out;hence the corrected temperatures were re-evaluated. the measurements were repeated at different delay times ranging from 1 to 5 μsec. this work emphasizes on the importance of correcting the emitted spectral line intensity against the effect of self absorption before using them in the calculation of plasma electron temperature in laser induced breakdown spectroscopy (LIBS) experiments.

关键词： LIBS Self Absorption mg-Lines Plasma Parameters

tiO2-based materials for photocatalytic hydrogen production

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Journal of Energy Chemistry 2017年第2期26卷 250-258页

作者： G.L.Chiarello m.v.Dozzi E.Selli Dipartimento di Chimica Universitàdegli Studi di MilanoVia Golgi 19I-20133 MilanoItaly

Hydrogen, the cleanest and most promising energy vector, can be produced by solar into chemical energy conversion, either by the photocatalytic direct splitting of water into Hand O, or, more efficiently,in the presence of sacrificial reagents, e.g., in the so-called photoreforming of organics. Efficient photocatalytic materials should not only be able to exploit solar radiation to produce electron–hole pairs, but also ensure enough charge separation to allow electron transfer reactions, leading to solar energy driven thermodynamically up-hill processes. Recent achievements of our research group in the development and testing of innovative tiO-based photocatalytic materials are presented here, together with an overview on the mechanistic aspects of water photosplitting and photoreforming of organics. Photocatalytic materials were either（i） obtained by surface modification of commercial photocatalysts, or produced（ii） in powder form by different techniques, including traditional sol gel synthesis, aiming at engineering their electronic structure, and flame spray pyrolysis starting from organic solutions of the precursors, or（iii） in integrated form, to produce photoelectrodes within devices, by radio frequency magnetron sputtering or by electrochemical growth of nanotube architectures, or photocatalytic membranes, by supersonic cluster beam deposition.

关键词： Photocatalytic H2 production Photo steam reforming Flame spray pyrolysis Nanotubes Noble metal nanoarticles Photocatalytic devices

Performance Analysis of OFDm Synchronization Using Customized Floating Point for Low Complexity

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Circuits and Systems 2016年第10期7卷 3112-3120页

作者： v. Janakiraman m. Kannan Department of Electronics and Communication Engineering Apollo Engineering College Chennai India Department of Electronics Engineering MIT Anna University Chennai India

Orthogonal frequency-division multiplexing (OFDm) is a multi carrier modulation scheme mainly used for digital communications. the performance of OFDm system heavily depends on the synchronization scheme used. In most cases, the accuracy level of synchronization will be worsened by the error caused in fixed point arithmetic involved. In this paper, we analyze the impact of the fixed point arithmetic on the performance of the coarse timing and frequency synchronization. Here with an analytical approach through numerical simulations bit length of IEEE 754 standard single precision format is optimized according to the required degree of accuracy for low complexity. Also, a complete precision level requirement for FFt computations with all possible modulation types is obtained. the proposed precision model is compared with IEEE standard single precision model and its efficiency in OFDm synchronization process is proved through mAtLAB simulations. Finally, the complexity reduction of proposed precision model in both addition and subtraction is proved against single precision format using hardware synthesis. Here we proved that more than 50% complexity reduction is achieved as compared to standard precision models without compromising quality. the quality retention of proposed model is proved in both timing and frequency synchronization process.

关键词： OFDm Fast Fourier transform Floating Point Aithmetic Synchronization Customization