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Germanium nanoislands grown by radio frequency magnetron sputtering: Annealing time dependent surface morphology and photoluminescence

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Chinese Physics B 2013年第9期22卷 600-604页

作者： Alireza Samavati z.Othaman S.k.Ghoshal R.J.Amjad Ibn Sina Institute for Fundamental Science Studies Universiti Teknologi Malaysia Advanced Optical Material Research Group Department of PhysicsFaculty of ScienceUniversiti Teknologi Malaysia

Structural and optical properties of ～ 20 nm Ge nanoislands grown on Si（100） by radio frequency （rI） magnetron sputtering under varying annealing conditions are reported. Rapid thermal annealing at a temperature of 600 ℃ for 30 s, 90 s, and 120 s are performed to examine the influence of annealing time on the surface morphology and photoluminescence properties. X-ray diffraction spectra reveal prominent Ge and GeO2 peaks highly sensitive to the annealing time. Atomic force microscope micrographs of the as-grown sample show pyramidal nanoislands with relatively high-density （～ 10^11 cm^-2）. The nanoislands become dome-shaped upon annealing through a coarsening process mediated by Oswald ripening. The room temperature photoluminescence peaks for both as-grown （～ 3.29 eV） and annealed （～ 3.19 eV） samples consist of high intensity and broad emission, attributed to the effect of quantum confinement. The red shift （～ 0.10 eV） of the emission peak is attributed to the change in the size of the Ge nanoislands caused by annealing. Our easy fabrication method may contribute to the development of Ge nanostructure-based optoelectronics.

关键词： germanium nanoislands radio frequency magnetron sputtering photoluminescence surface mor-phology

ON THE L_∞ CONVERGENCE AND THE EXTRAPOLATION METHOD OF A DIFFERENCE SCHEME FOR NONLOCAL PARABOLIC EQUATION WITH NATURAL BOUNDARY CONDITIONS

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Journal of Computational Mathematics 2001年第5期19卷 449-458页

作者： Wan, z.-S. Sun, z.-z. Institute of Applied Physics and CM P.O. Box 8009 Beijing 100088 China

In paper (J. Comput. Appl. Math., 76 (1996), 137-146), a difference scheme for a class of nonlocal parabolic equations with natural boundary conditions was derived by the method of reduction of order and the unique solvability and second order convergence in L2-norm are proved. In this paper, we prove that the scheme is second order convergent in L∞ norm and then obtain fourth order accuracy approximation in L∞ norm by extrapolation method. At last, one numerical example is presented.

关键词： Approximation theory Boundary conditions Convergence of numerical methods Extrapolation

Bell Polynomial Approach for the Solutions of Fredholm Integro- Differential Equations with Variable Coefficients

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Computer Modeling in Engineering & Sciences 2020年第6期123卷 973-993页

作者： Gökçe Yıldız Gültekin Tınaztepe Mehmet Sezer Department of Mathematics Faculty of ScienceManisa Celal Bayar UniversityManisaTurkey Vocational School of Technical Sciences Akdeniz UniversityAntalyaTurkey

In this article,we approximate the solution of high order linear Fredholm integro-differential equations with a variable coefficient under the initial-boundary conditions by Bell *** collocation points and treating the solution as a linear combination of Bell polynomials,the problem is reduced to linear system of equations whose unknown variables are Bell *** solution to this algebraic system determines the approximate *** estimation of approximate solution is *** examples are provided to illustrate the performance of the *** numerical results are compared with the collocation method based on Legendre polynomials and the other two methods based on Taylor *** is observed that the method is better than Legendre collocation method and as accurate as the methods involving Taylor polynomials.

关键词： Bell polynomials collocation points matrix method Fredholm integrodifferential equations.

Medium Range Prediction of Summer Monsoon Activities over India vis-a-vis Their Correspondence with the Observational Features

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Advances in Atmospheric Sciences 1999年第1期16卷 135-148页

作者： Swati Basu k. J. Ramesh z. N. Begum Department of Science and Technology National Centre for Medium Range Weather Forecasting (NCMRWF) New Delhi India

A detailed examination on various aspects of the southwest monsoon over the Indian subcontinent using analyses and forecasts of the NCMRWF global data assimilation and forecast system for the years 1994 and 1996 is carried out in this study. Objective procedures developed by Ramesh et al. (1996) based on the monsoon 1995 data are employed in the present work. It is found that all the deterministic features of the summer monsoon viz., the onset, its advancement, stagnation/revival and the withdrawal, can reasonably by prognosticated after employing the objective methodologies and monitoring daily variations of certain derived quantities from the large scale analyses and forecasts. Further, a good correspondence of the observed large scale/synoptic scale circulation features and the observed rainfall etc. with the deterministic characteristics of the summer monsoon show a good prospect for real time prognosis of the important summer monsoon activities over the Indian subcontinent.

关键词： Summer monsoon Objective procedure Onset Advancement Withdrawal

ENERGY-LOSS FUNCTIONS DERIVED FROM REELS SPECTRA FOR ALUMINUM

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 217-222页

作者： z.M.zhang z.J.Ding H.M.Li k.Salma X.Sun R.Shimizu T.koshikawa k.Goto StructureResearchLaboratoryandDepartmentofPhysics UniversityofScienceandTechnologyofChinaTheChineseAcademyofSciencesHefei230026China DepartmentofInformationScience OsakaInstituteofTechnologyOsaka573-0196Japan FundamentalElectronicsResearchInstitute OsakaElectro-CommunicationUniversityOsaka572-8530Japan DepartmentofSystemsEngineering NagoyaInstituteofTechnologyNagoya466-8555Japan

The effective energy loss functions for Al have been derived from differential i nverse inelastic mean free path based on the extended Landau approach. It has be en revealed that the effective energy loss function is very close in value to th e theoretical surface energy loss function in the lower energy loss region but g radually approaches the theoretical bulk energy loss function in the higher ener gy loss region. Moreover, the intensity corresponding to surface excitation in e ffective energy loss functions decreases with the increase of primary electron e nergy. These facts show that the present effective energy loss function describe s not only surface excitation but also bulk excitation. At last, REELS spectra s imulated by Monte Carlo method based on use of the effective energy loss functio ns has reproduced the experimental REELS spectra with considerable success.

关键词： effective energy loss function Monte Carlo simulation extended Landau approach reflection electron energy loss spectro scopy Aluminum

CHANGES OF GLOMERULAR FIXED ANIONIC CHARGE SITES IN ADRIAMYCIN NEPHROSIS IN RATS

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中华医学杂志(英文版) 1991年第2期104卷 128-131+176-177页

作者： z Wang z G Wang z Liu Department of Pediatrics Second Teaching Hospital West China University of Medical Sciences Chengdu.

A single intravenous injection of adriamycin (5 mg/kg) into rats induced nephrotic syndrome. In the various stages of the model, alterations of glomerular fixed anionic charge sites stained with colloidal iron were analyzed quantitatively by image analyzer, which is reported here for the first time. The results showed that there was a significant decrease in glomerular fixed anionic charge sites at 3 hours after administration of adriamycin as compared with the control animals (Pked loss of the anionic charge sites preceded the onset of proteinuria and steadily increased along with the progress of the disease. The results suggest that the loss of glomerular fixed anionic charge sites may play an important role in the development of proteinuria in nephrotic syndrome.

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Exergy analysis of R1234ze（z） as high temperature heat pump working fluid with multi-stage compression

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Frontiers in Energy 2017年第4期11卷 493-502页

作者： Bin HU Di WU L.W. WANG R.z. WANG Institute of Refrigeration and Cryogenics Shanghai Jiao Tong University Shanghai 200240 China

In this paper, the simulation approach and exergy analysis of multi-stage compression high tempera- ture heat pump （HTHP） systems with R1234ze（z） working fluid are conducted. Both the single-stage and multi-stage compression cycles are analyzed to compare the system performance with 120℃ pressurized hot water supply based upon waste heat recovery. The exergy destruction ratios of each component for different stage compression systems are compared. The results show that the exergy loss ratios of the compressor are bigger than that of the evaporator and the condenser for the single-stage compres- sion system. The multi-stage compression system has better energy and exergy etticiencies with the increase of compression stage number. Compared with the single- stage compression system, the coefficient of performance （COP） improvements of the two-stage and three-stage compression system are 9.1% and 14.6%, respectively. When the waste heat source temperature is 60℃, the exergy efficiencies increase about 6.9% and 11.8% for the two-stage and three-stage compression system respec- tively.

关键词： multi-stage compression high temperatureheat pump heat recovery exergy destruction,R1234ze(z) working fluid

Macro to nanoscale deformation of transformation-induced plasticity steels：Impact of aluminum on the microstructure and deformation behavior

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Journal of Materials Science & Technology 2018年第5期34卷 745-755页

作者： V.S.Y.Injeti z.C.Li B.Yu R.D.k.Misra z.H.Cai H.Ding Department of Metallurgical Materials and Biomedical Engineering500 W. University Avenue USA School of Materials Science and Engineering Northeastern University Shenyang 110819 China

This work aims to elucidate the impact of aluminum-content on microstructure and deformation mechanisms of transformation-induced plasticity（TRIP） steels through macroscale and nanoscale deformation experiments combined with post-mortem electron microscopy of the deformed *** solid-state transformation-induced mechanical deformation varied with the Al contents,and influenced tensile strength-ductility *** with 2–4 wt% Al were characterized by TRIP *** contrast to 2 Al-TRIP and 4 Al-TRIP steels,twinning-induced plasticity（TWIP） was also observed in conjunction with strain-induced martensite in 6 Al-TRIP *** behavior is attributed to the increase in stacking fault energy with the increase of Al content and stability of austenite,which depends on the local chemical *** study addresses the knowledge gap with regard to the effect of Al content on austenite stability in medium-Mn TRIP *** combination is expected to potentially enable cost-effective alloy design with high strength-high ductility condition.

关键词： Medium-manganese steels Aluminum content Electron microscopy Mechanical properties Nanoscale deformation TRIP steel Twinning

Steady vortex force theory and slender-wing flow diagnosis

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Acta Mechanica Sinica 2007年第6期23卷 609-619页

作者： Y.T.Yang R.k.zhang Y.R.An J.z.Wu State key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871China

The concept vortex force in aerodynamics is sys- tematically examined based on a new steady vortex-force theory （Wu et al., Vorticity and vortex dynamics, Springer, 2006） which expresses the aerodynamic force （and moment） by the volume and boundary integrals of the Lamb vector. In this paper, the underlying physics of this theory is explored, including the general role of the Lamb vector in non- linear aerodynamics, its initial formation, and its relevance to the total-pressure non-uniformity. As a typical example, the theory is applied to the flow over a slender delta wing at a large angle of attack. The highly localized flow structures with high Lamb-vector peaks are identified in terms of their net contribution to various constituents of the total aerody-namic force. This vortex-force diagnosis sheds new light on the flow control and configuration optimization.

关键词： Vortex force - Delta-wing - Flow control