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Microstructure and Hardness of T250 Maraging Steel in Heat Affected Zone

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Journal of Iron and Steel Research International 2009年第1期16卷 87-91页

作者： MO De-feng HU Zheng-fei chen Shu-juan WANG chun-xu HE Guo-qiu School of Material Science and Engineering Tongji University Shanghai 200092 China Central Iron and Steel Research Institute Beijing 100081 China

Electron-beam （EB） welding was used in T250 maraging steel, microstructures of both base material and heat affected zone （HAZ） were investigated by optical microscopy （OM）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）, and microhardness was tested. The results showed that during EB welding, the HAZ of T250 maraging steel exhibited a continuous gradient structure. The microstrueture of the entire HAZ, from fusion line, could be divided into four zones： fusion zone, overheated zone, transition zone, and hardened zone. The microhardness showed a distinct regularity in each area. The softest region was the fusion zone, whereas the hardest was the hardened zone. In the overheated zone, the hardness increased as the grain size decreased. Furthermore, in the transition zone, the hardness level dropped noticeably. The peak temperature during the thermal cycle had a great influence on the formation of reverted austenite and dissolution of the precipitated particles, which contributed a lot to the microstructure and hardness of this material.

关键词： T250 maraging steel electron-beam weld microstructure microhardness

Effect of CeO_2 and CaO Promoters on Ignition Performance for Partial Oxidation of Methane over Ni/MgO-Al_2O_3 Catalyst

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Journal of Natural Gas Chemistry 2007年第2期16卷 148-154页

作者： Yejun qiu Jixiang chen Jiyan Zhang Department of Catalysis Science and Engineering School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

The effect of CeO2 and CaO promoters on the ignition performance over Ni/MgO-Al2O3 catalyst for the partial oxidation of methane （POM） to synthesis gas was investigated. It was found that the POM reaction could not be ignited over lwt%Ni/MgO-Al2O3 catalyst without the promoters in the temperature range from 773 K to 1073 K. CeO2 and CaO promoters enhanced the ignition performance and the POM reactivity of lwt%Ni/MgO-Al2O3 catalyst remarkably. Moreover, the improving effect became greater with the increase of the promoter content under the investigated reactiorrconditions. The modification effects of CeO2 and CaO promoters were closely related to the concentration and reducibility of the surface and bulk oxygen species.

关键词： partial oxidation of methane synthesis gas nickel-based catalyst ignition cerium oxide calcium oxide

Molecular reconstruction model based on structure oriented lumping and group contribution methods

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Chinese Journal of Chemical Engineering 2018年第8期26卷 1677-1683页

作者： Jincai chen Zhou Fang Tong qiu Department of Chemical Engineering Tsinghua University

Molecular management is a promising technology to face challenges in the refining industry, such as more stringent requirements for product oil and heavier crude oil, and to maximize the value of every molecule in petroleum fractions. To achieve molecular management in refining processes, a novel model that is based on structure oriented lumping(SOL) and group contribution(GC) methods was proposed in this study. SOL method was applied to describe a petroleum fraction with structural increments, and GC method aimed to estimate molecular properties. The latter was achieved by associating rules between SOL structural increments and GC structures. A three-step reconstruction algorithm was developed to build a representative set of molecules from partial analytical data. First, structural distribution parameters were optimized with several properties. Then, a molecular library was created by using the optimized parameters. In the final step, maximum information entropy(MIE) method was applied to obtain a molecular fraction. Two industrial samples were used to validate the method, and the simulation results of the feedstock properties agreed well with the experimental data.

关键词： Molecular reconstruction Structure oriented lumping Group contribution Monte Carlo Maximum information entropy

Recent progress on lithium-ion batteries with high electrochemical performance

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Science China Chemistry 2019年第5期62卷 533-548页

作者： Yong Lu qiu Zhang Jun chen Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) College of ChemistryNankai University

Lithium-ion batteries(LIBs) have been widely used in many fields such as portable electronics and electric vehicles since their successful commercialization in the 1990 s. However, the electrochemical performance of current commercial LIBs still needs to be further improved to meet the continuously increasing demands for energy storage applications. Recently, tremendous research efforts have been made in developing next-generation LIBs with enhanced electrochemical performance. In this review, we mainly focus on the recent progress of LIBs with high electrochemical performance from four aspects, including cathode materials, anode materials, electrolyte, and separators. We discuss not only the commercial electrode materials(LiCoO_2,LiFePO_4, LiMn_2O_4, LiNi_xMn_yCo_zO_2, LiNi_xCo_yAl_zO_2, and graphite) but also other promising next-generation materials such as Li-, Mn-rich layered oxides, organic cathode materials, Si, and Li metal. For each type of materials, we highlight their problems and corresponding strategies to enhance their electrochemical performance. Nowadays, one of the key challenges to construct high-performance LIBs is how to develop cathode materials with high capacity and working voltage. This review provides an overview and future perspectives to develop next-generation LIBs with high electrochemical performance.

关键词： lithium-ion batteries electrochemical performance cathode anode electrolyte separator

Norcantharidin inhibits growth of human gallbladder carcinoma xenografted tumors in nude mice by inducing apoptosis and blocking the cell cycle in vivo

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Hepatobiliary & Pancreatic Diseases International 2010年第4期9卷 414-422页

作者： Fan, Yue-Zu Zhao, Ze-Ming Fu, Jin-Ye chen, chun-qiu Sun, Wei Tongji Univ Sch Med Tongji Hosp Dept Surg Shanghai 200065 Peoples R China Shanghai Jiao Tong Univ Peoples Hosp 9 Dept Surg Shanghai 200065 Peoples R China

BACKGROUND: Gallbladder carcinoma, a lethal malignant neoplasm with poor prognosis, has dismal results of surgical resection and chemoradiotherapy. We previously reported that norcantharidin (NCTD) is useful against growth, proliferation, and invasion of human gallbladder carcinoma GBC-SD cells in vitro. In this study, we further studied the inhibitory effect of NCTD on the growth of xenografted tumors of human gallbladder carcinoma in nude mice in vivo and the underlying mechanisms. METHODS: The tumor xenograft model of human gallbladder carcinoma in nude mice in vivo was established with subcutaneous GBC-SD cells. The experimental mice were randomly divided into control, 5-FU, NCTD, and NCTD+5-FU groups which were given different treatments. Tumor growth in terms of size, growth curve, and inhibitory rate was evaluated. Cell cycle, apoptosis, and morphological changes of the xenografted tumors were assessed by flow cytometry and light/electron microscopy. The expression of the cell cycle-related proteins cyclin-D1 and p27 as well as the apoptosis-related proteins Bcl-2, Box, and survivin were determined by the streptavidin-biotin complex (SABC) method and RT-PCR. RESULTS: NCTD inhibited the growth of the xenografted tumors in a dose- and time-dependent manner. Tumor volume decreased (5.61+/-0.39 vs. 9.78+/-0.61 cm(3), P=0.000) with an increased tumor inhibitory rate (42.63% vs. 0%, P=0.012) in the NTCD group compared with the control group. The apoptosis rate increased (15.08+/-1.49% vs. 5.49+/-0.59%, P=0.0001) along with a decreased percentage of cells in S phase (43.47+/-2.83% vs. 69.85+/-1.96%, P=0.0001) in the NTCD group compared with the control group. The morphological changes of apoptosis such as nuclear shrinkage, chromatin aggregation, chromosome condensation, and typical apoptosis bodies in the xenografted tumor cells induced by NCTD were observed by light and electron microscopy. The expression of cyclin-D1, Bcl-2 and survivin proteins/mRNAs decreased s

关键词： norcantharidin gallbladder neoplasm tumor growth apoptosis cell cycle

Geometrical statistical channel model arisen from scatterers around the mobile with an inverted-parabolic spatial distribution

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The Journal of China Universities of Posts and Telecommunications 2012年第5期19卷 1-8页

作者： ZHOU Jie LI chun-mei qiu Lin HISAKAZU Kikuchi Department of Communications Nanjing University of Information Science and Technology Nanjing 210044 China Department of Electronic and Electrical Engineering Niigata University Niigata 950-2181 Japan

In this paper, firstly presented a geometrically based statistical channel model with scatterers that are with an inverted parabolic spatial distribution around mobile station （MS） within a circle wherein the base station （BS） and MS are included. This paper proposed a technique to simply derive probability density functions （PDFs） of angle of arrival （AOA）, time of arrival （TOA） and Doppler spectra to characterize the outdoor macrocell and microcell environments by employing various distances between BS and MS, or different size of circular region. Employing this channel model, we analyze the impacts of a directional antenna at BS with the main-lobe width 2~z on the fading and the Doppler spectra.

关键词： inverted parabolic PDFs circular and elliptical scattering models directional antenna macrocell and microcell

Kinetic theory of geodesic acoustic modes in toroidal plasmas:a brief review

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Plasma Science and Technology 2018年第9期20卷 24-49页

作者： Zhiyong qiu Liu chen Fulvio ZONCA Institute for Fusion Theory and Simulation and Department of Physics Zhejiang University Department of Physics and Astronomy University of California ENEA Fusion and Nuclear Safety Department

Geodesic acoustic modes（GAM） are oscillating zonal structures unique to toroidal plasmas,and have been extensively studied in the past decades due to their potential capabilities of regulating microscopic turbulences and associated anomalous *** article reviews linear and nonlinear theories of GAM;with emphases on kinetic treatment,system nonuniformity and realistic magnetic geometry,in order to reflect the realistic experimental ***,in the linear physics,the resonant wave-particle interactions are discussed,with the application to resonant excitation by energetic particles（EPs）.The theory of EP-induced GAM（EGAM） is applied to realistic devices for the interpretation of experimental observations,and global effects due to coupling to GAM continuum are also ***,in the nonlinear physics,the spontaneous GAM excitation by microscale turbulences is reviewed,including the effects of various system nonuniformities.A unified theoretical framework of GAM/EGAM is then constructed based on our present *** first-principle-based GAM/EGAM theories reviewed here,thus,provide the tools needed for the understanding and interpretation of experimental/numerical results.

关键词： geodesic acoustic mode kinetic theory nonlinear physics energetic particle physics

Function Combined Method for Design Innovation of Children's Bike

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Chinese Journal of Mechanical Engineering 2013年第2期26卷 242-247页

作者： WU Xiaoli qiu Tingting chen Huijuan School of Mechanical and Electrical Engineering Hohai University Changzhou Key Digital Manufacturing Technology Laboratory Hohai University Suning Appliance Co. Ltd.

As children mature, bike products for children in the market develop at the same time, and the conditions are frequently updated. Certain problems occur when using a bike, such as cycle overlapping, repeating function, and short life cycle, which go against the principles of energy conservation and the environmental protection intensive design concept. In this paper, a rational multi-function method of design through functional superposition, transformation, and technical implementation is proposed. An organic combination of frog-style scooter and children’s tricycle is developed using the multi-function method. From the ergonomic perspective, the paper elaborates on the body size of children aged 5 to 12 and effectively extracts data for a multi-function children’s bike, which can be used for gliding and riding. By inverting the body, parts can be interchanged between the handles and the pedals of the bike. Finally, the paper provides a detailed analysis of the components and structural design, body material, and processing technology of the bike. The study of Industrial Product Innovation Design provides an effective design method to solve the bicycle problems, extends the function problems, improves the product market situation, and enhances the energy saving feature while implementing intensive product development effectively at the same time.

关键词： children’s bike function combined method ergonomics function transformed

Nitrogen-rich hierarchically porous carbon foams as high-performance electrodes for lithium-based dual-ion capacitor

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Journal of Energy Chemistry 2020年第9期29卷 187-194,I0006页

作者： Yue chen Xiaoming qiu Li-Zhen Fan Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Shanxi Key Laboratory of New Energy Materials and Devices Taiyuan University of TechnologyTaiyuan 030024ShanxiChina

Nitrogen-rich porous carbonaceous materials have shown great potential in energy storage and conversion applications due to their facile fabrication,high electronic conductivity,and improved hydrophilic ***,three-dimensional porous N-rich carbon foams are fabricated through a one-step carbonization-activation method of the commercial melamine foam,and displaying hierarchically porous structure(macro-,meso-,and micro-pores),large surface area(1686.5 m2 g^-1),high N-containing level(3.3 at%),and excellent *** as-prepared carbon foams as electrodes for quasi-solid-state supercapacitors exhibit enhanced energy storage ability with 210 F g^-1 and 2.48c at 0.1 A g^-1,and150 F g^-1 and 1.77 F cm^-2 at 1 A g^-1,***,as an electrode for lithium-based dual-ion capacitor,this distinctive porous carbon also delivers remarkable specific capacitance with 143.6 F g^-1 at0.1 A g^-1 and 116.2 F g^-1 at 1 A g^-*** simple preparation method and the fascinating electrochemical performance endow the N-rich porous carbon foams great prospects as high-performance electrodes for electrochemical energy storage.

关键词： Nitrogen-rich Carbon foam Hierarchically porous structure Dual-ion capacitor