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Chemical Research in Chinese Universities 2004年第4期20卷 396-402页

作者： YU j. j. Electronic & Electrical Engineering University College London

We have successfully demonstrated that high quality and high dielectric constant layers can be fabricated by low temperature photo-induced or -assisted processing. Ta_2O_5 and ZrO_2 have been deposited at t<400 ℃ by means of a UV photo-CVD technique and HfO_2 by photo-assisted sol-gel processing with the aid of excimer lamps. The UV annealing of as-grown layers was found to significantly improve their electrical properties. Low leakage current densities on the order of 10 -8 A/cm 2 at 1 MV/cm for deposited ultrathin Ta_2O_5 films and ca.10 -6 A/cm 2 for the photo-CVD ZrO_2 layers and photo-irradiated sol-gel HfO_2 layers have been readily achieved. The improvement in the leakage properties of these layers is attributed to the UV-generated active oxygen species O( 1D) which strongly oxidize any suboxides to form more stoichiometric oxides on removing certain defects, oxygen vacancies and impurities present in the as-prepared layers. The photo-CVD Ta_2O_5 films deposited across 10.16-cm Si wafers exhibit a high thickness uniformity with a variation of less than \{±2.0%\} being obtained for ultrathin ca.10 nm thick films. The lamp technology can in principle be extended to larger area wafers, providing a promising low temperature route to the fabrication of a range of high quality thin films for future ULSI technology.

关键词： Excimer lamp High-kdielectrics Thin film Chemical vapour deposition(CVD) Sol-gel processing

Indian plate paleogeography, subduction and horizontal underthrusting below Tibet: paradoxes, controversies and opportunities

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National Science Review 2022年第8期9卷 175-193页

作者： Douwe j.j.van Hinsbergen Department of Earth Sciences Utrecht University

The India–Asia collision zone is the archetype to calibrate geological responses to continent–continent collision, but hosts a paradox: there is no orogen-wide geological record of oceanic subduction after initial collision around 60–55 Ma, yet thousands of kilometers of post-collisional subduction occurred before the arrival of unsubductable continental lithosphere that currently horizontally underlies Tibet. Kinematically restoring incipient horizontal underthrusting accurately predicts geologically estimated diachronous slab break-off, unlocking the Miocene of Himalaya–Tibet as a natural laboratory for unsubductable lithosphere convergence. Additionally, three endmember paleogeographic scenarios exist with different predictions for the nature of post-collisional subducted lithosphere but each is defended and challenged based on similar data types. This paper attempts at breaking through this impasse by identifying how the three paleogeographic scenarios each challenge paradigms in geodynamics, orogenesis, magmatism or paleogeographic reconstruction and identify opportunities for methodological advances in paleomagnetism, sediment provenance analysis, and seismology to conclusively constrain Greater Indian paleogeography.

关键词： collision orogenesis subduction reconstruction Himalaya Tibet

Application of CCD Cameras to Investigations of Mixing on Boundaries of a Thermal Plasma jet

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Plasma Science and Technology 2007年第6期9卷 743-746页

作者： j.HLINA j.SONSKY j.SLECHTA Institute of Thermomechanics Academy of Sciences of the Czech RepublicDolejskova 5182 00 Praha 8Czech Republic

Mixing of a thermal plasma jet with the surrounding atmosphere was studied using two CCD cameras （PCO SensiCam） situated detecting simultaneously the radiation of argon and nitrogen. The evaluation of image differences between two records showed that the location of regions on plasma jet boundaries characterised by stronger nitrogen radiation changes with the plasma flow rate. Close-to-laminar flow results in a small mixing rate and consequently low nitrogen optical emission on plasma jet boundaries. The increase of the flow rate leads to the formation of a relatively thick and stable layer on the boundaries characterised by strong nitrogen radiation. Further enhancement of the flow rate results in the formation of unstable regions of excited nitrogen molecules moving along the jet.

关键词： thermal plasma jet mixing CCD camera

Design,fabrication,characterization and reliability study of CMOS-MEMS Lorentz-force magnetometers

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Microsystems & Nanoengineering 2022年第5期8卷 17-41页

作者： j.j.Valle j.M.Sánchez-Chiva D.Fernández j.Madrenas Department of Electronic Engineering Universitat Politècnica de CatalunyaJordi Girona 1 i 3Edifici C408034 BarcelonaSpain Sorbonne Université CNRSLaboratoire de Recherche en Informatique(LIP6)UMR76064 place Jussieu75005 ParisFrance Institut de Física d’Altes Energies(IFAE) The Barcelona Institute of Science and Technology(BIST)Edifici Cn.Facultat Ciències NordUniversitat Autónoma de Barcelona08193 Bellaterra(Barcelona)Spain

This article presents several design techniques to fabricate micro-electro-mechanical systems(MEMS)using standard complementary metal-oxide semiconductor(CMOS)*** were applied to fabricate high yield CMOS-MEMS shielded Lorentz-force magnetometers(LFM).The multilayered metals and oxides of the back-end-of-line(BEOL),normally used for electronic routing,comprise the structural part of the *** most important fabrication challenges,modeling approaches and design solutions are *** that predict the Q factor,sensitivity,Brownian noise and resonant frequency as a function of temperature,gas pressure and design parameters are presented and validated in characterization tests.A number of the fabricated magnetometers were packaged into Quad Flat No-leads(QFN)*** show this process can achieve yields above 95%when the proper design techniques are *** CMOS not being a process for MEMS manufacturing,estimated performance(sensitivity and noise level)is similar or superior to current commercial magnetometers and others built with MEMS ***,typical offsets present in Lorentz-force magnetometers were prevented with a shielding electrode,whose efficiency is ***,several reliability test results are presented,which demonstrate the robustness against high temperatures,magnetic fields and acceleration shocks.

关键词： Lorentz magnetometer characterization

Bulk and surface damages in complementary bipolar junction transistors produced by high dose irradiation

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Chinese Physics B 2018年第1期27卷 430-437页

作者： j Assaf Atomic Energy Commission Damascus Syria

Two complementary types NPN and PNP of bipolar junction transistors （BjTs） were exposed to higll dose of neutrons and gamma rays. The change in the base and collector currents, minority carriers lifetime, and current gain factor/3 with respect to the dose were analyzed. The contributions of the base current according to the defect types were also reported. It was declared that the radiation effect of neutrons was almost similar between the two transistor types, this effect at high dose may decrease the value of/3 to less than one. The Messenger-Spratt equation was used to describe the experimental results in this case. However, the experimental data demonstrated that the effect of gamma rays was generally higher on NPN than PNP transistors. This is mainly attributed to the difference in the behavior of the trapped positive charges in the SiO2 layers. Meanwhile, this difference tends to be small for high gamma dose.

关键词： bipolar junction transistors radiation effects surface damage bulk damage

General aspects on structural integrity

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Chinese journal of Aeronautics 2019年第1期32卷 114-132页

作者： j.j.XIONG R.A.SHENOI School of Transportation Science and Engineering Beihang University Faculty of Engineering and Environment University of Southampton

This paper seeks to mark the fruitful collaborative research between scholars in the University of Southampton and Beihang University for last 25 years on structural integrity. Their efforts addressed some important issues in structural integrity such as fatigue and fracture behavior,fatigue load spectra, fatigue and fracture lifetimes, reliability-based service period, adhesively bonded composite patch repairs, Plain Woven Fabric(PWF) composites and composite *** advances in engineering approaches, experimental methods, numerical algorithms and understanding of failure mechanisms relating to structural integrity are highlighted. Probable limits(or drawbacks) are also discussed. This review provides an insight into the general aspects on structural integrity and constitutes a basis for pointers to the further works on structural integrity.

关键词： Composites Fatigue Fracture Reliability Repair Structural integrity

Effect of surface layer softening from previous electrochemical corrosion on electrochemical cold drawing of Q235 steel bar

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journal of Iron and Steel Research International 2022年第5期29卷 819-835页

作者： j.L.Guo T.j.Chen State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou730050GansuChina

The effects of H_(2)SO_(4)concentration and current in electrochemical corrosion on surface layer softening or plasticizing of Q235 steel bar and their effects on subsequent electrochemical cold drawing(ECD)were *** results indicate that the electrochemical corrosion can soften or plasticize the surface layer of Q235 steel bar and then make the subsequent ECD be conducted more *** softening degree and thickness of the surface layer are continuously enhanced with increasing corrosion rate,i.e.,increasing H_(2)SO_(4)concentration or current,due to the generation of more vacancy clusters in deeper regions of surface *** vacancy clusters then relax dislocations through being absorbed during ECD,and the formation and movement of additional dislocation flux are thereby enhanced,resulting in the further obvious decrease in the drawing *** is also due to the enhanced formation and movement of additional dislocation flux that the dislocation density and thus the hardness of the surface layer are decreased,as well as that the texture structure is *** behaviors are enhanced as the corrosion rate increases.

关键词： Electrochemical corrosion Electrochemical cold drawing Surface layer softening Vacancy Additional dislocation flux

A study on distributive and modular lattice ordered fuzzy soft group and its duality

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Applied Mathematics(A journal of Chinese Universities) 2016年第4期31卷 491-502页

作者： j Arockia Reeta j Vimala Department of Mathematics Alagappa University

Soft set theory has a rich potential application in several fields. A soft group is a parameterized family of subgroups and a fuzzy soft group is a parameterized family of fuzzy subgroups. The concept of fuzzy soft group is the generalization of soft group. Abdulkadir Aygunoglu and Halis Aygun introduced the notion of fuzzy soft groups in 2009[1]. In this paper, the concept of lattice ordered fuzzy soft groups and its duality has been introduced. Then distributive and modular lattice ordered fuzzy soft groups are analysed. The objective of this paper is to study the lattice theory over the collection of fuzzy soft group in a parametric manner. Some pertinent properties have been analysed and hence established duality principle.

关键词： Fuzzy soft set fuzzy soft group lattice ordered fuzzy soft groups distributive lattice orderedfuzzy soft groups modular lattice ordered fuzzy soft groups.

Accuracy details in realistic CFD modeling of an industrial centrifugal pump in direct and reverse modes

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journal of Thermal Science 2010年第6期19卷 491-499页

作者： j.C. Páscoa F. j. Silva j.S. Pinheiro D.j. Martins Department of Electromechanical Engineering Center for Aerospace Sciences and Technology University of Beira Interior EFAFLU Bombas e Ventiladores S.A. R. S. Brás 269 Apartado 23 4494-909 Póvoa do Varzim Portugal

Numerical computation of the flowfield inside a pump is herein used as a numerical laboratory, subject to the limitations of modeling assumptions and to experimental verification. A numerical computation of the flow inside a real industrial centrifugal pump is performed that includes a very sophisticated geometry. Conversely to other computations, in this test case no simplification of the geometry was introduced. Numerical computations are obtained using Spalart-Allmaras turbulence model. A detailed analysis of the turbulent flowstructure is performed for the design point and two off design conditions. Additional computations were performed in order to compare the numerical and experimental pump characteristics; these were obtained under normalized testing conditions. Further computations are presented for the pump working in reverse turbine mode (PAT). Detailed analyses of the flow allow a comparison of the internal flow losses when the pump is operating in direct and reverse mode. This is also useful to help in the selection of an adequate pump geometry that can work in both modes with best efficiency.

关键词： centrifugal pump impeller turbulence modeling Spalart-Allmaras PAT

Effects of the Reversely Rotating Assisted Shoulder on Microstructures During the Reverse Dual-rotation Friction Stir Welding

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journal of Materials Science & Technology 2015年第4期31卷 375-383页

作者： j.Q.Li H.j.Liu State Key Laboratory of Advanced Welding and joining Harbin Institute of Technology Capital Aerospace Machinery Company

The reverse dual-rotation friction stir welding(RDR-FSW) has the capability to adjust the heat generation because of the separately designed tool shoulder and tool *** welding torque exerted on the workpiece by the reversely rotating shoulder is opposite to that exerted by the rotating tool pin,so the total welding torque is reduced,which is beneficial to reducing the clamping requirement of *** the present paper,a RDR-FSW joint was welded in a condition similar to the optimal welding condition of conventional FSW,and microstructures in various zones were investigated by comparison,aiming to highlight effects of the reversely rotating assisted *** to the heat conduction of the middle cylinder and the bottom end cover on which the assisted shoulder was machined,the thermal effect of RDR-FSW was smaller than that of the conventional ***,the effect of assisted shoulder on the plastic flow or deformation of material or was constrained in a thin layer near the weld top surface,and thus the flow of material especially along the thickness direction was clearly decreased in the *** the heat-affected zone(HAZ),the precipitate coarsening was the main evolution and was completed through the dissolution of small precipitates and the continuous growth of large *** contrast,the dissolution degree of precipitates increased significantly in the thermomechanically affected zone(TMAZ),and a small amount of original meta-stable precipitates transformed to block-shaped stable *** evolutions in the shoulder affected zone(SAZ)and the weld nugget zone were similar,*** majority of original meta-stable precipitates dissolved into the matrix and the remainder transformed to stable precipitates,though the dissolution degree was greater in the *** with the conventional FSW joint,the coarsening degrees of precipitates in the HAZ and TMAZ of RDR-FSW joint were much smaller,as well as the dissolution degrees of p

关键词： Friction stir welding Reverse dual-rotation fricti