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Sintering behavior and properties of SiC/Si_3N_4 composite

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Rare Metals 2015年第2期34卷 95-100页

作者： Yong Jiang lan-Er Wu Wen-zhou Sun School of Materials Science and Engineering Beifang University of Nationalities

SiC/Si_3N_4 composite was pressureless sintered using self-propagating high-temperature combustion synthesis a-Si_3N_4 powder and appropriate amount of b-SiC powder. Both of the sintering additive systems were used,which were YAN（Y_2O_3–Al_2O_3–AlN） and YN（Y_2O_3–AlN）.The influences of b-SiC content on sintering behavior of SiC/Si_3N_4 composite were investigated. The results show that the density, shrinkage, bending strength, hardness, and fracture toughness of the samples with two sintering additive systems increase first with the increase of the contents of b-SiC and then decrease even when b-SiC contents continually increase. The tendency of weight loss of the samples is opposite. The b-SiC content of the samples with the best mechanical properties is different in two systems. For YAN system, the best mechanical properties of the samples are gained when b-SiC content reaches 10 %, while as for YN system it is 5 %. The properties of YN samples are superior to YAN samples. J phase（2Y_2O_3 ·Si_2N_2O） forms in YN system easily. A small amount of M phase（Y_2O_3·Si_3N_4） is observed in YAN system.

关键词： SHS powder β-SIC SiC/Si_3N_4 composite Sintering behavior Properties

Effect of Austempering Route on Microstructural Characterization of Nanobainitic Steel

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Acta Metallurgica Sinica(English Letters) 2014年第1期27卷 19-26页

作者： Huifang lan Linxiu Du Na zhou Xianghua Liu State Key Laboratory of Rolling and Automation Northeastern University Hebei Shougang Qian'an Iron & Steel Co. Ltd

A low-temperature nanobainitic steel was obtained through one-step and two-step austempering. The effect of austempering temperature, time, and route on bainitic lath width, volume fraction of retained austenite, carbon concen- tration in retained austenite, and nanohardness of bainitic lath and retained austenite was studied. Results showed that the transformation kinetics was slowed down and the bainitic lath was refined as the austempering temperature decreased from 300 to 250 C. Both coarser and finer bainitic laths were obtained with the two-step austempering, which was consistent with the lath size at 300 and 250 C austempering, respectively. X-ray diffraction analysis showed that both volume fraction of retained austenite and its carbon concentration decreased with the decrease of austempering temperature for the one-step austempering, and especially the carbon concentration is obviously increased when the two-step austempering is adopted. The nanohardness of the bainitic lath in the sample after two-step austempering treated lies between that of the samples after 300 and 250 C austempering treated. The product of tensile strength and total elongation of the two-step austempered sample is the highest, which increases monotonously with the product of retained austenite fraction and its carbon concentration. Higher strengthluctility balance may be resulted by the fine bainitic lath, high volume fraction, and high stability of retained austenite in the sample after two-step austempered.

关键词： Nanobainitic steel Stability Retained austenite Nanohardness Strength-ductility balance

Application of multiwalled carbon nanotubes treated by potassium permanganate for determination of trace cadmium prior to flame atomic absorption spectrometry

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Journal of Environmental Sciences 2007年第10期19卷 1266-1271页

作者： XIAO Jun-ping zhou Qing-xiang BAI hua-hua Department of Chemistry University of Science and Technology Beijing Beijing 100083 China Henan Key Laboratory for Environmental Pollution Control School of Chemistry and Environmental Sciences Henan Normal University Xinxiang 453007 China

In this study we investigated the enrichment ability of oxidized multiwalled carbon nanotubes （MWCNTs） and established a new method for the determination of trace cadmium in environment with flame atomic absorption spectrometry. The MWCNTs were oxidized by potassium permanganate under appropriate conditions before use as preconcentration packing. Parameters influencing the recoveries of target analytes were optimized. Under optimal conditions, the target analyte exhibited a good linearity （R^2=0.9992） over the concentration range 0.5-50 ng/ml. The detection limit and precision of the proposed method were 0.15 ng/ml and 2.06%, respectively. The proposed method was applied to the determination of cadmium in real-world environmental samples and the recoveries were in the range of 91.3%-108.0%. All these experimental results indicated that this new procedure could be applied to the determination of trace cadmium in environmental waters.

关键词： multiwalled carbon nanombes (MWCNTs) solid-phase extraction flame atomic absorption spectrometry

Control Algorithm of Electric Vehicle in Coasting Mode Based on Driving Feeling

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Chinese Journal of Mechanical Engineering 2015年第3期28卷 479-486页

作者： SUN Daxu lan Fengchong zhou Yunjiao CHEN Jiqing School of Mechanical & Automotive Engineering South China University of Technology Key Laboratory of Guangdong Province of Automotive Engineering South China University of Technology

Coasting in gear is a common driving mode for the conventional vehicle equipped with the internal combustion engine（ICE）, and the assistant braking function of ICE is utilized to decelerate the vehicle in this mode. However, the electric vehicle（EV） does not have this feature in the coasting mode due to the relatively small inertia of the driving motor, so it will cause the driver cannot obtain the similar driving feeling to that of the conventional vehicle, and even a traffic accident may occur if the driver cannot immediately adapt to the changes. In this paper, the coasting control for EV is researched based on the driving feeling. A conventional vehicle equipped with continuously variable transmission（CVT） is taken as the reference vehicle, and the combined simulation model of EV is established based on AVL CRUISE and MATLAB/Simulink. The torque characteristic of the CVT output shaft is measured in coasting mode, and the data are smoothed and fitted to a polynomial curve. For the EV in coasting mode, if the state of charge（SOC） of the battery is below 95%, the polynomial curve is used as the control target for the torque characteristic of the driving motor, otherwise, the required torque is replaced by hydraulic braking torque to keep the same deceleration. The co-simulation of Matlab/Simulink/Stateflow and AVL CRUISE, as well as the hardware-in-loop experiment combined with d SPACE are carried out to verify the effectiveness and the real-time performance of the control algorithm. The results show that the EV with coasting braking control system has similar driving feeling to that of the reference vehicle, meanwhile, the battery SOC can be increased by 0.036% and 0.021% in the initial speed of 100 km/h and 50 km/h, respectively. The proposed control algorithm for EV is beneficial to improve the driving feeling in coasting mode, and it also makes the EV has the assistant braking function.

关键词： electric vehicle coasting braking control algorithm engine braking motor braking

CYCLOPEPTIDE FROM THE SEEDS OF ANNONA GLABRA

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Chinese Chemical Letters 1995年第1期6卷 39-40页

作者： Chao Ming LI Ning hua TAN Hui lan ZHENG Xiao Jiang HAO Jun zhou Acad Sinica Kunming Inst Bot Lab Phytochem Kunming 650204 Peoples R China Acad Sinica Kunming Inst Bot Xishuangbanna Trop Bot Garden Mengla 666303 Peoples R China

A new cyclopeptide glabrin A has been isolated from the seeds of Annona glabra. Its structure was elucidated by 2D-NMR and FAB-MS.

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Structure and Evolution of Decadal Spiciness Variability in the North Pacific during 2004-20,Revealed from Argo Observations

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Advances in Atmospheric Sciences 2022年第6期39卷 953-966页

作者： Guanghui zhou Rong-hua ZHANG CAS Key Laboratory of Ocean Circulation and Waves Institute of Oceanologyand Center for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100029China Laboratory for Ocean and Climate Dynamics Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China Center for Excellence in Quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China

Ocean spiciness is referred to as density-compensated temperature and salinity variations with warm(cool)and salty(fresh)waters having high(low)spiciness,*** structure and evolution of density-compensated(warm/salty or cool/fresh)spiciness anomalies are investigated in the North Pacific thermocline using Argo observations during the period *** well-organized decadal spiciness events are identified through isopycnal surface *** warm/salty spiciness anomaly of about 0.15°C and 0.05 g kg^(−1)temperature and salinity perturbations on the 25 kg m^(−1)isopycnal surface appeared in the eastern subtropical North Pacific at(18°-30°N,120°-150°W)in 2007,which then migrated southwestward along the mean circulation and arrived in the western tropics at(~15°N,145°E-175°W)in 2012-13,with the reduced salinity perturbation of about 0.043 g kg^(−1).Another cool/fresh spiciness anomaly of about−0.2°C and−0.07 g kg^(−1)temperature and salinity perturbations originated from the eastern subtropics at(120°-150°W,~30°N)in 2014 and followed a similar advective pathway during the period from 2014-15 to *** subduction pathway can be adequately determined by the mean Montgomery stream function on the isopycnal surface;the propagation direction and speed are in good agreement with the expectation for the role played by advection due to the mean geostrophic ***,the subducted decadal spiciness anomalies can have negative feedback on sea surface temperature(SST)variability in the western tropical Pacific through the diapycnal *** identifications of these density-compensated spiciness anomalies and their propagation pathways provide a clear illustration of the oceanic extratropics-tropics interactions in the North Pacific Ocean.

关键词： isopycnal analysis spiciness anomalies subduction pathway advection role decadal variability North Pacific

Herpesviruses: epidemiology, pathogenesis, and interventions

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Virologica Sinica 2017年第5期32卷 347-348页

作者： Ke lan Min-hua Luo State Key Laboratory of Virology College of Life Sciences Wuhan University State Key Laboratory of Virology CAS Center for Excellence in Brain Science and Intelligence Technology (CEBSIT) Wuhan Institute of Virology Chinese Academy of Sciences

This special issue of the journal is dedicated to the recent research progress on human herpesviruses(HHVs).Human herpesviruses are distributed worldwide,and more than 90%of adults are infected by one or multiple *** ... 详细信息

关键词： simplex pathogenesis herpes epidemiology infected spherical dedicated replication interferon zoster

Effect of wall boundary condition on CFD simulation of CFB risers

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Particuology 2013年第5期11卷 556-565页

作者： Xinyu zhou Jinsen Gao Chunming Xu Xingying lan State Key Laboratory of Heavy Oil Processing China University of Petroleum

The effect of solid-phase wall boundary condition on the numerical simulation of gas-solid flow in CFB risers containing FCC particles was investigated using the two-fluid model incorporating the kinetic the- ory of granular flow. Both the Gidaspow drag model and the EMMS-based drag model were used. The Johnson and Jackson （1987） wall boundary condition was applied to describe the interaction between particles and wall. Based on the experimental system of Li and Kwauk （1994）, parametric studies of spec- ularity coefficient （cp = 1.0, 0.6, 0.0005, 0.00005, 0） and particle-wall restitution coefficient （ew = 0.6, 0.9, 0.95, 0.99, 0.999） were performed to evaluate their effects on axial voidage profile, solids flux, meso-scale and heterogeneous structures. Simulation results showed that solid-phase wall boundary condition had little effect on axial voidage profile when the Gidaspow drag model was used. However, the specular- ity coefficient ~a had a pronounced influence on flow behavior when the EMMS-based drag model was used, and a small specularity coefficient （cp = 0.00005, 0） could result in better agreement with exper- imental data. The particle-wall restitution coefficient ew plays but a minor role in the holistic flow characteristics.

关键词： JCirculating fluidized bedBoundary conditionEMMSCFDSpecularity coefficientParticle-wall restitution coefficient

Microwave-hydrothermal synthesis,characterization and upconversion luminescence of rice-like Gd(OH)_(3) nanorods

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Rare Metals 2022年第12期41卷 4273-4278页

作者： Shuang huang hua-lan Xu Lei Wang Sheng-Liang Zhong College of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China

Rice-like Gd(OH)_(3)nanorods were successfully prepared through a facile and rapid microwave-hydrothermal synthesis method without using any surfactants or templates.X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectroscopy,thermogravimetric analysis(TGA),scanning electron microscopy(SEM),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),selected area electron diffraction(SAED)and energy-dispersive spectroscopy(EDS)were used to characterize the *** show that the nanorods have an average length of 400 nm and an average diameter of 50 *** effects of reaction parameters such as reaction temperature and time on the preparation were briefly *** is found that the crucial factor for the formation of rice-like Gd(OH)3nanorods is reaction *** the rice-like Gd(OH)3nanorods was codoped with Yb^(3+)and Er^(3+),strong upconversion emissions could be observed under the excitation of 980-nm-laser,and the calculated CIE color coordinates falls within the yellow region,which may be potential candidate for optical materials.

关键词： Microwave-hydrothermal synthesis Gadolinium hydroxide Upconversion Rare earth