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Manufacturing and testing of X-ray imaging components with high precision

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光学精密工程 2005年第5期13卷 620-625页

作者： HU jia sheng WU Xü School of Electronic and Information Engineering Dalian University of Technology Dalian 116024China College of Information Technology Dalian Maritime University Dalian 116026 China

In the latest 20 years, X ray imaging technology has developed rapidly in order to meet the needs of X-ray photo-etching, spatial exploration technology, high-energy physics, procedure diagnosis of ICF,etc. Since refractive indices of materials in the X-ray region are lower than 1, and X-ray is strongly absorbed by materials, the characteristics of X-ray increase greatly difficulty to obtain X-ray image. Conventional imaging methods are hardly suitable to X-ray range. In general, grazing reflective imaging and coding aperture imaging methods have been adopted more and more. We have designed a non coaxial grazing reflective X ray microscope which is composed of four spherical mirrors, in order to satisfy the requirement of the diagnosis of inertial confinement fusion （ICF）. The four mirrors have the same radius of curvature. The radius of each mirror is 29 000 mmand the aperture is 30 mm×15 mm. Allowable tolerance of the radius is ≤0.2% and one of surface roughness （rms） is ≤0.6 nm. Evidently it is very difficult to fabricate and test such mirrors. In order to obtain eligible mirrors, we choose 18 mirror roughcasts and array them on a round disk according to format. The combined manufacturing method can ensure high accordant quality. The fabricated mirrors are tested by both templet and double round aperture methods. Radius errors of the mirrors is about 53 mm. The surface roughness （rms） of the mirrors is inspected by the relative interferometric equipment （WYKO） and atomic force microscope. Before and after coating the measured surface roughness is averagely 0.52 nm and 0.4 nm, respectively.

关键词： X光线图像质量评价纳米精度

含Fe3S3簇核的两个异构体化合物的合成和结构研究

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化学学报 1988年第10期46卷 972-977页

作者：刘平黄梁仁王玲玲康北笙卢嘉锡中国科学院福建物质结构研究所福州

用氯化亚铁、苯硫酚钠及溴化四乙基铵在乙腈溶液中,经一步反应,得到两个同分异构的化合物α-[Et4N]3[Fe3(PhS)3Cl3Br3]1和β-[Et4N]3[Fe3(PhS)3Cl3Br3]2.X射线晶体结构测定表明,1和2的阴离子骨架为3Fe、3S交叉排列的六元环.

关键词： Fe3S3 六元环原子构成化合物

Uniform Exponential Attractor for Nonautonomous Partly Dissipative Lattice Dynamical System

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Acta Mathematica Sinica,English Series 2014年第8期30卷 1381-1394页

作者： sheng Fan ZHOU jia jia LOU Department of Mathematics Zhejiang Normal University Zhengzhou 63 Middle School

In this paper,we consider the existence of a uniform exponential attractor for the nonautonomous partly dissipative lattice dynamical system with quasiperiodic external forces.

关键词： Nonautonomous partly dissipative lattice systems uniform exponential attractor continuous process

A Photometric Study of the W UMa-Type Contact Binary RZ Com

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Chinese Journal of Astronomy and Astrophysics 2008年第4期8卷 465-471页

作者： jia-jia He sheng-Bang Qian National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China United Laboratory of Optical Astronomy Chinese Academy of Sciences （ULOAC） Beijing 100012 China Graduate School of Chinese Academy of Sciences Beijing 100049 China

We present results of CCD photometric observations of the short-period W UMatype contact binary system, RZ Com. The light curve of the binary has changed from Wsubtype to A-subtype from 1998 to 2003, then back to W-subtype in 2004. An analysis was carried out using the 2003 version of the Wilson-Devinney code. It is confirmed that RZ Com is a low-degree, overcontact f = 20.1% （±7.4%） binary system with a high inclination of i = 81.°40 （＋0.°40）, and a mass ratio q = 2.351 （＋0.031）. Combining four newly determined times of light minimum with others in the literature, the variations in orbital period is examined. A small-amplitude oscillation （A=0.0065d）, with a period of 41.5 year, is discovered superimposed on a long-term increase at rate dP/dt = ＋3.97 × 10^-8d yr^-1. The period oscillation can be explained either by the light-time effect due to the presence of an unseen third body, or by cycles of magnetic activity on the components. Combining our photometric solution with the spectroscopic elements obtained by Mclean ＆ Hilditch, the absolute dimensions ofRZ Com are： M1 = 1.14 （±0.19）M⊙, M2 = 0.50 （±0.09）M⊙, R1 = 1.12 （±0.01）R⊙, R2 = 0.78 （＋0.01）R⊙ and A = 2.41 （±0.02）R⊙.

关键词： stars binaries close - stars binaries eclipsing - stars individual RZ Com

Unsteady Flow Separation and High Performance of Airfoil with Local Flexible Structure at Low Reynolds Number

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Communications in Computational Physics 2014年第8期16卷 699-717页

作者： Peng-Fei Lei jia-Zhong Zhang Wei kang sheng Ren Le Wang School of Energy and Power Engineering Xi’an Jiaotong UniversityXi’an 710049P.R.China. School of Astronaustics Northwestern Polytechnical UniversityXi’an 710072P.R.China.

The unsteady flow separation of airfoil with a local flexible structure(LFS)is studied numerically in Lagrangian frames in detail,in order to investigate the nature of its high aerodynamic *** such aeroelastic system,the characteristicbased split(CBS)scheme combined with arbitrary Lagrangian-Eulerian(ALE)framework is developed firstly for the numerical analysis of unsteady flow,and Galerkin method is used to approach the flexible *** local flexible skin of airfoil,which can lead to self-induced oscillations,is considered as unsteady perturbation to the ***,the ensuing high aerodynamic performances and complex unsteady flow separation at low Reynolds number are studied by Lagrangian coherent structures(LCSs).The results show that the LFS has a significant influence on the unsteady flow separation,which is the key point for the lift ***,the oscillations of the LFS can induce the generations of moving separation and vortex,which can enhance the kinetic energy transport from main flow to the boundary *** results could give a deep understand of the dynamics in unsteady flow separation and flow control for the flow over airfoil.

关键词： Unsteady flow moving separation aeroelastic structure lift enhancement Lagrangian coherent structures

CO_(2)flooding in shale oil reservoir with radial borehole fracturing for CO_(2)storage and enhanced oil recovery

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Petroleum Science 2024年第1期21卷 519-534页

作者： jia-Cheng Dai Tian-Yu Wang Jin-Tao Weng kang-jian Tian Li-Ying Zhu Gen-sheng Li State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China China National Oil and Gas Exploration and Development Company Limited Beijing100034China

This study introduces a novel method integrating CO_(2)flooding with radial borehole fracturing for enhanced oil recovery and CO_(2)underground storage,a solution to the limited vertical stimulation reservoir volume in horizontal well fracturing.A numerical model is established to investigate the production rate,reservoir pressure field,and CO_(2)saturation distribution corresponding to changing time of CO_(2)flooding with radial borehole fracturing.A sensitivity analysis on the influence of CO_(2)injection location,layer spacing,pressure difference,borehole number,and hydraulic fractures on oil production and CO_(2)storage is *** CO_(2)flooding process is divided into four *** in layer spacing will significantly improve oil production rate and gas storage ***,serious gas channeling can occur when the spacing is lower than 20 *** the pressure difference between the producer and injector,the borehole number,the hydraulic fracture height,and the fracture width can also increase the oil production rate and gas storage *** analysis shows that layer spacing and fracture height greatly influence gas storage and oil *** outcomes are expected to provide a theoretical basis for the efficient development of shale oil reservoirs in the vertical direction.

关键词： Shale oil Radial borehole fracturing Embedded discrete fracture model Enhanced oil recovery Carbon storage

Evaluation and Model of Performance of A Tubular Solid Oxide Fuel Cell

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Chemical Research in Chinese Universities 2005年第5期21卷 577-582页

作者： jia Jun-xi SHEN sheng-qiang Department of Power Engineering Dalian University of Technology Dalian 116024 P. R. China

A simulation model was developed to analyze the steady state and transient operation of a tubular solid oxide fuel cell. The model covers both the electrochemical and the heat transfer models. The electrochemical model deals with the Nernst potential, ohmic polarization, activation polarization, and concentration polarization, while the heat transfer model concerns the heat transfer by conduction, convection and radiation. The numerical results show that the ohmic loss is the dominant one among the three polarizations in a cathode-supported solid oxide fuel cell and in the middle part of a solid oxide fuel cell the temperature is higher than those at both the ends. When the inlet temperature and the flow rates of the fuel and the oxidant are kept constantly, the temperature of the solid structure of the cell will increase due to the increase of power output of the cell from the initial state to the new one.

关键词： Tubular solid oxide fuel cell Polarization Electrochemical reaction Heat and mass transfer

Carbon nanotube supported bifunctional electrocatalysts containing iron-nitrogen-carbon active sites for zinc-air batteries

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Nano Research 2021年第12期14卷 4541-4547页

作者： jian sheng sheng Zhu Guodong jia Xu Liu Yan Li Beijing National Laboratory for Molecular Sciences Key Laboratory for the Physics and Chemistry of NanodevicesState Key Laboratory of Rare Earth Materials Chemistry and ApplicationsCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China Peking University Shenzhen Institute Shenzhen518057China PKU-HKUST ShenZhen-HongKong Institution Shenzhen518057China

Bifunctional electrocatalysts with high activity toward both oxygen reduction and evolution reaction are highly desirable for rechargeable Zn-air batteries. Herein, a kind of carbon nanotube (CNT) supported single-site Fe-N-C catalyst was fabricated via pyrolyzing in-situ grown Fe-containing zeolitic imidazolate frameworks on CNTs. CNTs not only serve as the physical supports of the Fe-N-C active sites but also provide a conductive network to facilitate the fast electron and ion transfer. The as-synthesized catalysts exhibit a half-wave potential of 0.865 V for oxygen reduction reaction and a low overpotential of 0.442 V at 10 mA·cm^(−2) for oxygen evolution, which is 310 mV smaller than that of Fe-N-C without CNTs. The rechargeable Zn-air batteries fabricated with such hybrid catalysts display a high peak power density of 182 mW·cm^(−2) and an excellent cycling stability of over 1,000 h at 10 mA·cm^(−2), which outperforms commercial Pt-C and most of the reported catalysts. This facile strategy of combining single-site Metal-N-C with CNTs network is effective for preparing highly active bifunctional electrocatalysts.

关键词： single atoms Fe-N-C sites carbon nanotube bifunctional electrocatalyst zinc-air batteries

Suspected SARS-CoV-2 infection with fever and coronary heart disease:A case report

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World Journal of Clinical Cases 2020年第23期8卷 6056-6063页

作者： Jin-Ru Gong jia-sheng Yang Yao-Wei He kang-Hui Yu jia Liu Rui-Lin Sun Department of Pulmonary and Critical Care Medicine Guangdong Second Provincial General HospitalGuangzhou 510317Guangdong ProvinceChina Department of Radiology Guangdong Second Provincial General HospitalGuangzhou 510317Guangdong ProvinceChina

BACKGROUND The coronavirus disease 2019(COVID-19)is an emerging infectious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Suspected cases accounted for a large proportion in the early stage of the COVID-19 *** deviation of the nucleic acid test by throat swab(the current gold standard of COVID-19)caused by variation in sampling techniques and reagent kits and coupled with nonspecific clinical manifestations make confirmation of the suspected cases *** management of the suspected cases of COVID-19 is crucial for disease *** SUMMARY A 65-year-old male presented with fever,lymphopenia,and chest computed tomography(CT)images similar to COVID-19 after percutaneous coronary *** patient was diagnosed as having bacterial pneumonia with cardiogenic pulmonary edema instead of *** was based on four negative results for throat swab detection of SARS-CoV-2 nucleic acid using reverse transcriptase-polymerase chain reaction assay and one negative result for serological antibody of SARS-CoV-2 with the serological ***,the distribution of ground-glass opacities and thickened blood vessels from the CT images differed from COVID-19 features,which further supported the exclusion of *** Distinguishing COVID-19 patients from those with bacterial pneumonia with cardiogenic pulmonary edema can be ***,it requires serious identification.

关键词： COVID-19 Suspected case Nucleic acid test Serological antibody detection Ground-glass opacities Case report