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On some tests-based projection pursuit for elliptical symmetry of a high-dimensional distribution

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Chinese science Bulletin 1998年第6期43卷 450-458页

作者： JING Ping 1 and zhu Lixing 2.1. Mathematics Lab, china {2. of Mining & technology, beijing 100083, china 2. Probability Lab, Institute of Applied Mathematics, Chinese Academy of sciences, beijing 100080, china Mathematics Lab China University of Mining & Technology Beijing China Probability Lab Institute of Applied Mathematics Chinese Academy of Sciences Beijing China

Some test statistics of Kolmogorov type and Cramér-von Mises type based on projection pursuit technique are proposed for the testing problem of sphericity of a high-dimensional distribution. The limiting distributions of the test statistics are derived under the null hypothesis and under any fixed alternative. The asymptotic properties of bootstrap approximation are investigated. Furthermore, for computational reasons, an approximation for the statistics, based on the number theoretic method, is suggested.

关键词： bootstrap approximation projection pursuit type statistic elliptical symmetry.

Zero-Thermal Expansion and Heat Capacity of Zirconium Pyrovanadate Doped with Zirconia and Vanadium (V) Oxide

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Rare Metals 2001年第1期20卷 1-4页

作者： Xianran Xing, Zhenqi zhu, Xinping Qiu, Guirong Liu (Dept. of Physical Chemistry{2., beijing 100083, china Dept. of Chemistry, Tsinghua university, beijing 100084, china) Univ Sci & Technol beijing Dept Phys Chem Beijing 100083 Peoples R China Tsing Hua Univ Dept Chem Beijing 100084 Peoples R China

The dominant phase ZrV2.7 material, doped with zirconia and vanadium (V) oxide, was synthesized by solid state reaction and sol-gel methods. X-ray power diffraction patterns show that it is cubic structure. Thermal mechanic analysis measurements exhibit a zero-thermal expansion of this material above 150 degreesC. Meanwhile, the heat capacity dependent on temperature, determined by differential scanning calorimetry, keeps in constant almost in the same temperature range. The relationship between unusual thermal expansion and abnormal heat capacity is discussed with Gruneisen parameter.

关键词： zero-thermal expansion of ZrV2.7 heat capacity Gruneisen parameter

THERMAL NUCLEATION AND GROWTH OF He BUBBLES IN He IMPLANTED STAINLESS STEELS

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Acta Metallurgica Sinica(English Letters) 1993年第3期6卷 186-190页

作者： ZHANG Lei WANG Peixuan TAO rong MA Ruzhang ZHANG Guoguang university of science and technology beijing,{2.,china professor,Department of Materials Physics.university of science and technology {2..{2. 100083,china beijing Univ of science and Technology Beijing China

Nucleation and growth of He bubbles at different annealing temperatures T≤102. K in stain- less steels HR-2.and SS32.,implanted with He^+(40-70 keV.1×10^(16)-6× 10^(17) He^+/cm^2.,were ohserved under TEM.T=0.45T_m seems to be a transition *** He bubbles continue mainly their nucleation at 0.3T_m2.and SS32. *** bubble density in HR-2.is greater than that in SS32. within whole measuring temperature range,and the onset temperature of rapid swelling is also *** is believed that the resistance of HR-2.to He is superior to that fo SS32..

关键词： stainless steel ion implantation He bubble steel SS32. steel HR-2

Study on Tribological Properties of the Rolling Fluid Containing Nano-MoS_2.for Cold Rolling of Steel Strip

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china Petroleum Processing & Petrochemical technology 2011年第1期13卷 64-69页

作者： zhu Guangping Sun Jianlin Wang Bing Wang Yizhu ({2. of Materials and Engineering,university of science and technology beijing,beijing 100083) Univ Sci & Technol beijing Sch Mat & Engn Beijing 100083 Peoples R China

The nano-MoS2.particles were adopted to substitute for the extreme-pressure and anti-wear additives to the rolling fluid for steel *** optimal formulation and technical process for adding nano-MoS2.particles to the rolling fluid were obtained through orthogonal experiments with three factors at three *** tests have led to the following conclusions:(a) the nanoparticles should be added to a base oil with high saponification value;(b) the concentration of nanoparticles in rolling fluid should be equal to 0.6%;and (c) when the reaction time needed for surfactants (oleic acid,for example) to modify the nanoparticles was 40 min,the rolling fluid could have the best tribological *** lubricity of rolling fluid was verified by using a 4-high cold rolling test mill which showed that the rolling fluid with nano-MoS2.particles had the excellent lubricant performance to improve the surface quality of the steel strip *** mechanism of nano-MoS2.particles in the rolling process has been investigated by a series of characterization instruments,which have showed that,with its fullerene-like structure,the nano-MoS2.particles have self-lubricating properties and extra-low friction coefficient,and can easily form a protective film with low shear strength on the surface of friction pairs.

关键词： cold rolling nano-MoS2 strip rolling fluid mechanism

XPS Studies of Chemical States of NiO/NiFe Interface

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Journal of university of science and technology beijing 2001年第4期8卷 270-273页

作者： Guanghua Yu, Chunlin Chai, Fengwu zhu, Jimei Xiao, Wuyan Lai 1)Materials science and Engineering {2., university of science and technology beijing, beijing 100083, china 2.Institute of Physics. Chinese Academy of sciences. beijing, 100080, china Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Chinese Acad Sci Inst Phys Beijing 100080 Peoples R China

Ta/NTiO/NiFe/Ta multilayers were prepared by radio frequency reactive and dc magnetron sputtering. The exchange coupling field between NiO and NiFe reached 9.6 x 10(3) A/m. The compositions and chemical states at the interface region of NiO/NiFe were studied using the X-ray photoelectron spectroscopy (XPS) and peak decomposition technique, The results show that there are two thermodynamically favorable reactions at NiO/NiFe interface: NiO+Fe = Ni + FeO and 3NiO+2.e =3 Ni+Fe2.3. The thickness of the chemical reaction area estimated by angle-resolved XPS was about 1-1.5 nm. These interface reaction products appear magnetic defects, and the exchange coupling field H-ex and the coereivity H-c of NiO/NiFe are affected by these defects.

关键词： chemical states exchange coupling field H-ex coercivity H-c X-ray photoelectron spectroscopy (XPS)

The Effect of Nb on Mechanical Properties of Quenching and Partitioning Steels

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Journal of Iron and Steel Research International 2011年第S1期18卷 306-309页

作者： zhu Shuai,KANG Yong-lin,REN Kang-kang,WANG Chuan (school of Materials {2. and Engineering.university of {2. and technology beijing,beijing 100083,china) Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

In order to study the effect of alloy elements on mechanical properties of quenching and partitioning steels,the Q and P heat treatments on different chemical composition steels were carried on in *** tensile test results indicated the strength of Nb+Ti-bearing steel was not increasing as expected,but lower than that of the Nb+Ti-free steel,and the elongation was raised to 2.% from 9%.The Nb+Ti-bearing steel microstructures after tensile test were detected by TEM and found a certain amount of twins in the deformed microstructure while the deformed microstructure mainly was lath martensite in Nb+Ti-free steel,which means the addition of Nb and Ti elements could cause the twinning induced plasticity by inhibiting the phase transformation from austenite to *** on above analysis,adding trace Nb element could greatly increase the stacking fault energy of the retained austenite,which is beneficial to the formation of twins,and the formation of twins would lower the strength slightly and raise the elongation drastically.

关键词： quenching and partitioning twinning induced plasticity niobium stacking fault energy

Subchronic toxicological effects of aquatic nitrobenzene on Medaka and Chinese rare minnow

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science china Chemistry 2007年第5期50卷 707-717页

作者： ZHOU QunFang1, FU JianJie1,2. MENG HaiZhen1,2. zhu XueYan1,2. JIANG GuiBin1, ZHANG JianBin1, LIU JieMin2.& SHI GuoQing2.1 State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-environmental sciences, Chinese Academy of sciences, beijing 100085, china 2.Department of Chemistry, school of Applied science, university of science and technology beijing, beijing 100083, china State Key Laboratory of Environmental Chemistry and Ecotoxicology ResearchCenter for Eco-environmental SciencesChinese Academy of SciencesBeijing 100085China Department ofChemistry School of Applied ScienceUniversity of Science and Technology B

Based on the simulative exposure experiments of nitrobenzene to two small experimental fishes, Medaka (Oryzias latipes) and Chinese Rare Minnow (Gobiocypris rarus), it was found that nitrobenzene could decrease in a linear way in the static aquatic system. Both fishes could accumulate dose-related levels of nitrobenzene quickly and eliminate the compound rapidly when they were transferred to clean water. The Chinese rare minnow showed more sensitivity to the acute toxicity exposure of nitrobenzene than Medaka. Typical molecular biomarkers in oxidative defense system including superoxide dismu- tase (SOD), catalase (CAT) showed the chemical induced alterations. The changes of acetylcholi- nesterase (AChE) activities indicated that nitrobenzene might affect the normal neural function. Nitro- benzene exposure could also lead to obvious damaging effects on the target organs, such as gill and liver by hitopathological studies.

关键词： nitrobenzene, Medaka, Chinese rare minnow, bioaccumulation, elimination, molecular biomarkers, histopathological effects

Force Parameter Model of 3-Roll Mills for Continuous Cold Rolling Wires

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International Journal of Minerals,Metallurgy and Materials 1999年第4期13卷 292-295页

作者： Baolong Zheng1 Li Sun2.Ruichen An2.Jin Wang1 Weichang zhu1(l Material science and Engineering {2., university of science and technology beijing, beijing 100083, china2.Tangshan iron and Steel Co. Ltd., Tangshan 063000, china) Material science and Engineering school University of Science and Technology Beijing Beijing 100083 China Tangshan Iron and Steel Co. Ltd. Tangshan 063000 China

Based on experimental data, the mathematical model of rolling force parameters of 3-roll mills was studied. The structure ofthe model was theoretically set up and the coefficients were determined by static analysis of the data. The torque in continuous rollingwas measured, and the characteristics and efficiency of 3-roll mills are investigated.

关键词： 3-roll mill force mathematical model cold rolling wire

Corrosion-Facilitating Local Plastic Deformation for α-Ti in Methanol

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Journal of Materials science & technology 1998年第2期14卷 188-190页

作者： Hong LU Tiancheng ZHANG and Wuyng CHU(Dept. of Material Physics, university of science & {2. beijing, 100083 beijing, china)Wanxu zhu Xunqing SHI and Baochen LIU( Dept. of Surface science & Corrosion Engineering, university of science & {2. Dept. of Material Physics University of Science and Technology Beijing 100083 Beijing China Dept. of Surface science and Corrosion Engineering University of Science and Technology Beijing Beijing 100083 China Dept. of Engineering Mechanics Tsinghua University China

The effect of corrosion process on facilitating local plastic deformation for α-Ti in methanol has been investigated with the micro-multiplicative moire interferometer technique. The size of plastic zone and the plastic strain ahead of loaded notch have been measured. The results show that the anodic dissolution, or corrosion process itself can enhance the plastic zone and the plastic strain ahead of a loaded notch during stress corrosion of α-Ti in methanol solution

关键词： Ti in Methanol Corrosion-Facilitating Local Plastic Deformation for