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Frontiers of Chemical Science and Engineering 2014年第2期8卷 133-140页

作者： Yan LI Zhehao wei yong wang Voiland School of Chemical Engineering and Bioengineering Washington State University Pullman WA 99164 USA

A Ni/MgO catalyst was prepared via novel dielectric-barrier discharge （DBD） plasma decomposition method. The combined characterization of Bmnauer- Emmett-Teller measurement, X-ray diffraction, hydrogen temperature-programmed reduction and transmission electron microscopy shows that DBD plasma treatment enhances the support-metal interaction of Ni/MgO catalyst and facilitates the formation of smaller Ni particles. Sphere-like Ni particles form on plasma treated Ni/MgO catalysts. The plasma treated Ni/MgO catalyst shows a significantly improved low temperature activity and good stability for CO2 reforming of methane to syngas.

关键词： CO2 reforming methane dielectric-barrierdischarge (DBD) plasma Ni/MgO

Remote-controlled module-assisted synthesis of O-(2-[^(18)F]fluoroethyl)-L-tyrosine as tumor PET tracer using two different radiochemical routes

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Nuclear Science and Techniques 2006年第3期17卷 148-153页

作者： wang Ming-wei YIN Duan-Zhi ZHANG Lan ZHOU wei wang yong-Xian Radiopharmaceutical Centre Shanghai Institute of Applied Physics the Chinese Academy of Sciences Shanghai 201800 China

The positron-emitter fluorine-18 labeled amino acid O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET) has shown very promising perspectives for brain tumor diagnosis with positron emission tomography (PET). There have been two existing preparation routes of [18F]FET named direct nucleophilic radiofluorination of protected L-tyrosine and radiofluoroalkylation of unprotected L-tyrosine, respectively. A general module was designed specifically for the routine synthesis of [18F]FET, which could be suitable for the present two chemical methods with simple modifica- tions. The fluorinated intermediates and the final product were separated and purified using solid phase extraction (SPE) on the Sep-Pak silica plus cartridge instead of the time-consuming high performance liquid chromatography (HPLC) procedures. The total synthesis time was about 50—60 min with good radiochemical yield (about 20—40%, no-decay-corrected) and good radiochemical purity (more than 97%) for both the synthetic methods.

关键词： PET 氟化作用合成模块正电子发射亲质子

Firmness measurement of peach by impact force response

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第12期10卷 883-889页

作者： yong-wei wang Jun wang Chong YAO Qiu-jun LU Department of Biosystems Engineering Zhejiang University Hangzhou 310029 China

The impact force response of a peach impacting on a metal flat-surface was considered as nondestructive determination of firmness. The objectives were to analyze the effect of firmness, drop height, fruit mass, and impact orientation on the impact force parameters, and to establish a relationship between the impact force parameter and firmness. The effect of fruit firmness, drop height and fruit mass on the impact force parameters (coefficient of restitution, percentage of energy absorbed, and coefficient of force-time) was evaluated. The study found that the coefficient of restitution, percentage of energy absorbed, and force-time impact coefficient were significantly affected by fruit ripeness, but not affected by drop height, impact position (fruit cheek), and mass. The percentage of absorbed energy increased with ripeness, while the force-time impact coefficient and coefficient of restitution decreased with ripeness. Relationships were obtained between the three impact characteristic parameters (force-time impact coefficient, coefficient of restitution, and percentage of energy absorbed) and peach firmness using a polynomial model (R2=0.932), S model (R2=0.910), and exponential model (R2=0.941), respectively.

关键词： Firmness Peach Impact force Coefficient of restitution Percentage of absorbed energy

Formation and preferred growth behavior of grooved seed silicon substrate for kerfless technology

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Chinese Physics B 2019年第6期28卷 343-348页

作者： Jing-Yuan Yan yong-wei wang yong-Ming Guo wei Zhang Cong wang Bao-Li An Dong-Fang Liu College of Sciences Shanghai UniversityShanghai 200444China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China

Kerfless technology is a promising alternative for reducing cost and providing flexible thin crystals in silicon-based semiconductors. In this work we propose a protruded seed substrate technology to prepare flexible monocrystalline Si thin film economically. Grooved seed substrate is fabricated by using SiNx thin film as a mask for the wet-etching and thermal oxidation process. After the SiNx layer on the wedged strip is removed by hot phosphoric acid, the pre-defined structured substrate is achieved with the top of the strip serving as the seed site where there is no oxide layer. And a preferred growth of epitaxial Si on the substrate is performed by introducing an intermittent feed method for silicon source gas. The technique in this paper obviously enhances the mechanical stability of the seed structure and the growth behavior on the seed sites, compared with our previous techniques, so this technique promises to be used in the industrial fabrication of flexible Si-based devices.

关键词： kerfless grooved seed substrate preferred growth

Study of Thermal Radiation Properties of Pyrolytic Carbon Protective Coatings for Monocrystalline Silicon Furnace

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Journal of Harbin Institute of Technology(New Series) 2013年第4期20卷 36-40页

作者： wei-wei Cao Bo Zhu wei Zhao yong-wei wang Yang Chen Xi-Hai wang College of Materials Science and Engineering Tianjin Polytechnic University Taishan Sports Industry Group College of Materials Science and Engineering Shandong University weifang Wuzhou Wind Power Equipment Co. Ltd

The thermal radiation properties of pyrolytic carbon(PyC)protective coatings for monocrystalline silicon furnace prepared by different processes were *** changes of normal emissivity of carbon materials caused by PyC protective coatings were discussed,and the influence of phase structure and surface appearance on the thermal radiation properties was *** results show that the thermal radiation properties of PyC protective coatings with the wave band of 5-25μm are better than C/C substrate,further,normal spectral emissivity of CVD PyC coating remains basically at 0.85-0.90,and the normal total emissivity can reach0.89,which shows high thermal radiation *** resin PyC coating and CVD PyC coating,the degree of graphitization are 44.53%and 16.28%respectively,and the R value of Raman spectrum are 0.964and 1.384 *** disorder graphite structure of the latter causes various vibration modes,and the spectral emissivity is better,so the thermal radiation property of CVD PyC coating is excellent.A lot of spherical particles exists on the surface of the CVD PyC coating,and the more interface and spacing of particles reduce the number of particles per unit ***,the scattering of thermal radiation is strongly strengthened,and the spectral emissivity is higher.

关键词： Monocrystalline silicon furnace PyC protective coating Normal spectral emissivity Normal total emissivity Graphite structure

Mean First-Passage Time of an Asymmetric Kinetic Model Driven by Two Different Kinds of Colored Noises

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Communications in Theoretical Physics 2008年第3期49卷 689-695页

作者： LI Dong-Xi XU wei GUO yong-Feng wang Liang Department of Applied Mathematics Northwestern Polytechnical University Xi＇an 710072 China

The mean first-passage time （MFPT） of an asymmetric bistable system between multiplicative non-Gaussian noise and additive Gaussian white noise with nonzero cross-correlation time is investigated. Firstly, the non-Markov process is reduced to the Markov process through a path-integral approach; Secondly, the approximate Fokker Planck equation is obtained by applying the unified colored noise approximation and *** Theorem. The steady-state probability distribution （SPD） is also obtained. The basal functional analysis and simplification are employed to obtain the approximate expressions of MFPT T^±. The effects of the asymmetry parameter β, the non-Gaussian parameter （measures deviation from Gaussian character） r, the noise correlation times τ and τ2, the coupling coefficient A, the intensities D and a of noise on the MFPT are discussed. It is found that the asymmetry parameter β, the non-Gaussian parameter r and the coupling coefficient A can induce phase transition. Moreover, the main findings are that the effect of self-existent parameters （D, α, and τ） of noise and cross-correlation parameters （A, 7-2） between noises on MFPT T^± is different.

关键词： mean first-passage time asymmetric bistable system non-Gaussian noise Gaussian noise

Manufacturing process and microstructure of copper-coated aluminum wires

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International Journal of Minerals,Metallurgy and Materials 2015年第2期22卷 190-196页

作者： Xiao-hua Chen Xin Tang Zi-dong wang Xi-dong Hui Mo Li yong-wei wang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing School of Materials Science and Engineering Georgia Institute of Technology School of Materials Science and Engineering University of Science and Technology Beijing School of Mechanical Engineering University of Science and Technology Beijing

Copper-coated aluminum wires exhibit good electrical conductivity, high thermal conductivity, low contact resistance of copper and low density, and provide economic advantages over aluminum. However, there are some problems in the manufacring processes of hot-dip copper-coated aluminum wires, such as the difficulties in controlling coating process. In this work, the hot-dip copper-coating method of aluminum wires was investigated for producing copper-coated aluminum wire composites. The interface microstructure between the aluminum wire and the copper coating layer was analyzed by scanning electron microscopy （SEM） and energy-dispersive X-ray spec- trometry （EDS）. Five different fluxing agents were tested. Experimental results show that appropriate conditions for the hot-dip process are determined as the liquid copper temperature of 1085℃ and the treatment time less than 1 s. A success in hot-dip copper-coated aluminum wires is achieved by hot-dipping a low-melting-point metal into a high-melting-point metal liquid, which is significant for the further devel- opment and application of copper-coated aluminum wire composites.

关键词： bimetallic composites copper aluminum hot dip coating interfaces

Gamma-ray Bursts: a Probe of Black Holes

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Chinese Journal of Astronomy and Astrophysics 2001年第6期1卷 487-493页

作者： wei wang and yong-Heng Zhao National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

There is strong evidence for the existence of black holes (BHs) in some X-ray binaries and in most galactic nuclei based on different types of measurement, but black holes have not been definitely identified for the lack of very firm observational evidence up to now. Because direct evidence for BHs should come from determination of strong gravitational redshift, we expect an object can fall into the region near the BH horizon where radiation can be detected. Therefore the object must be a compact star such as a neutron star (NS), and intense astrophysical processes will release highly energetic radiation that is transient and fast-varying. These characteristics may point to the observed gamma-ray bursts (GRBs). Recent observations of iron lines suggest that afterglows of GRBs show properties similar to those observed in active galactic nuclei (AGNs), implying that the GRBs may originate from intense events related to black holes. A model for GRBs and after-glows is proposed here to obtain the range of gravitational redshifts (zg) of GRBs with known cosmological redshifts. Here, we provide a new method that, with a search for high-energy emission lines (X- or -γ-rays) in GRBs, one can determine the gravitational redshift. We expect zg to be 0.5 or even larger, so we can rule out the possibility of other compact objects such as NSs, and identify the central progenitors of GRBs as black holes.

关键词： black hole physics - accretion accretion disks - gamma rays: burst

An approach for evaluating fire resistance of high strength Q460 steel columns

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Frontiers of Structural and Civil Engineering 2014年第1期8卷 26-35页

作者： wei-yong wang Guo-Qiang LI Bao-lin YU School of Civil Engineering Chongqing University Chongqing 400045 China State Key Laboratory for Disaster Reduction in Civil Engineering School of Civil Engineering Tongji University Shanghai 200092 China Department of Civil and Environmental Engineering Michigan State University East Lansing M1 48824 USA

To develop a methodology for evaluating fire resistance of high strength Q460 steel columns, the load bearing capacity of high strength Q460 steel columns is investigated. The current approach of evaluating load bearing capacity of mild steel columns at room temperature is extended to high strength Q460 steel columns with due consideration to high temperature properties of high strength Q460 steel. The critical temperature of high strength Q460 steel column is presented and compared with mild steel columns. The proposed approach was validated by comparing the predicted load capacity with that evaluated through finite element analysis and test results. In addition, parametric studies were carried out by employing the proposed approach to study the effect of residual stress and geometrical imperfections. Results from parametric studies show that, only for a long column （slenderness higher than 75）, the magnitude and distribution mode of residual stress have little influence on ultimate load bearing capacity of high strength Q460 steel columns, but the geometrical imperfections have significant influence on any columns. At a certain slenderness ratio, the stability factor first decreases and then increases with temperature rise.

关键词： high strength Q460 steel load bearing capacity temperature

Spectral Properties of Anomalous X-ray Pulsars

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Chinese Journal of Astronomy and Astrophysics 2003年第6期3卷 543-550页

作者： Ye Lu, wei wang and yong-Heng ZhaoNational Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 National Astronomical Observatories CAS NAOC Beijing 100012 China

We examine the spectra of the persistent emission from anomalous X-ray pulsars (AXPs) and their variation with the spin-down rate . Based on an accretion-powered model, the influences of both the magnetic field and the mass accretion rate on the spectral properties of AXPs are addressed. We then investigate the relation between the spectral property of AXPs and mass accretion rate . The result shows that there exists a linear correlation between the photon index and the mass accretion rate: the spectral hardness increases with increasing . A possible emission mechanism for the explanation of the spectral properties of AXPs is also discussed.

关键词： pulsars: general stars: neutron X-rays: stars accretion: accretion disks