检索结果-南通市图书馆

Effect of annealing temperature on structure and electrochemical properties of LiCoO_2 cathode thin films

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

rare Metals 2006年第Z2期25卷 189-192页

作者： yang Zhimin XING Guangjian yang Jian MAO Changhui DU jun Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China Department of Materials Science and Engineering Beijing Institute of Petrochemical Technology Beijing 102617 China Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China Advanced Electronic Materials Institute General Research Institute for Nonferrous Metals Beijing 100088 China

LiCoO2 thin films, which can be used as a cathode material in microbatteries, were deposited using radio frequency (r.f.) magnetron sputtering system from a LiCoO2 target and in an O2+Ar atmosphere. The films were characterized by various methods such as XrD, SEM and AFM. The LiCoO2 films were annealed in air at 300, 500, 700 and 800 ℃ respectively. The effect of the annealing temperature on the structure, the surface morphology and the electrochemical properties of the films were investigated. The LiCoO2 thin film deposited at room temperature is amorphous and has smaller grain size. With increasing of annealing temperature, the crystallinity of the films is promoted. When the annealing temperature increases to 700 ℃, the films have a perfect crystalline LiCoO2 phase. The LiCoO2 thin film without annealing has no discharge plateau and small discharge capacity (about 27 μAh·cm-2μm). The discharge capacity increases with the increasing of annealing temperature and reaches 47 μAh·cm-2μm for the film annealed with 700 ℃, which also shows the typical discharge plateau of 3.9 V. The cycle performance of LiCoO2 thin films of as grown and annealed at different temperatures were studied. In the case of the film without thermal treatment, the capacity fading is much faster than that of the film annealed at different temperature, showing about 40% capacity loss only after 25 cycles. However, in the case of the film annealed at 700 ℃, the capacity reaches to steady state gradually and maintained constantly with cycling. After 25 times cycling, the discharge capacity of the film annealed at 700 ℃ decreases to about 36.9 μAh·cm-2·μm, only 0.8% capacity loss per cycle.

关键词： LiCoO2 thin film annealing temperature structure electrochemical properties

rNF213 in moyamoya disease: Genotype-phenotype association and the underlying mechanism

在线全文

学校读者我要写书评

暂无评论

中华医学杂志(英文版) 2024年第21期137卷 2552-2560页

作者： Fang Jianxun yang Xinzhuang Ni jun Department of Neurology Peking Union Medical College Hospital Peking Union Medical College and Chinese Academy of Medical Sciences Beijing China Medical research Center Peking Union Medical College Hospital Peking Union Medical College and Chinese Academy of Medical Sciences Beijing China

Moyamoya disease (MMD) is a cerebrovascular disorder characterized by a steno-occlusive internal carotid artery and compensatory vascular network formation. Although the precise pathogenic mechanism remains elusive, genetic association studies have identifiedrNF213 as the principal susceptibility gene for MMD, with the single nucleotide polymorphism p.r4810K recognized as the founder variant predominantly in the Asian populations. Distinct genotype-phenotype correlations are observable inrNF213-related MMD. The clinical manifestations linked to p.r4810K bear commonalities within Asian cohort, including familial predisposition, earlier age of onset, ischemic episodes, and involvement of the posterior cerebral artery (PCA). However, despite these shared phenotypic characteristics, there is significant heterogeneity inrNF213-related MMD presentations. This diversity manifests as variations across ethnic groups, inconsistent clinical symptoms and prognosis, and occurrence of other vasculopathies involvingrNF213. This heterogeneity, in conjunction with the observed low disease penetrance ofrNF213 mutations, suggests that the presence of these mutations may not be sufficient to cause MMD, underscoring the potential influence of other genetic or environmental factors. Although the current research might not have fully identified these additional contributors, experimental evidence points toward the involvement ofrNF213 in angiogenesis, lipid metabolism, and the immune response. Future research is required to unveil the molecular mechanisms and identify the factors that synergize withrNF213 in the pathogenesis of MMD.

关键词： Moyamoya disease rNF213 Polymorphism p.r4810K

Sharp bilinear decomposition for products of both anisotropic Hardy spaces and their dual spaces with its applications to endpoint boundedness of commutators

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2024年第9期67卷 2091-2152页

作者： jun Liu Dachun yang Mingdong Zhang School of Mathematics China University of Mining and TechnologyXuzhou 221116China Laboratory of Mathematics and Complex Systems(Ministry of Education of China) School of Mathematical SciencesBeijing Normal UniversityBeijing 100875China

Let a:=(a_(1),...,a_(n))2[1,∞)^(n),p∈(0,1),andα:=1/*** any x∈r^(n)and t∈[0,∞),letΦ_(p)(x,t):={t/1+(t[x]_(a)^(ν))^(1-p)if να■N,t/1+(t[x]_(a)^(ν))^(1-p)[log(e+|x|a)]^(p)if να∈N,let where [·]a:=1+|·|a,|·|a denotes the anisotropic quasi-homogeneous norm with respect to a,and ν:=a_(1)+…+a_(n).Let H_(a)^(p)(r^(n)),L_(a)^(a)(r^(n)),and H_(a)^(Φ_(p))(r^(n))be,respectively,the anisotropic Hardy space,the anisotropic Campanato space,and the anisotropic Musielak-Orlicz Hardy space associated with Φ_(p) on r^(n).In this article,via first establishing the wavelet characterization of anisotropic Campanato spaces,we prove that for any f∈H_(a)^(p)(r^(n))and g∈L_(a)^(a)(r^(n)),the product of f and g can be decomposed into S(f,g)+T(f,g) in the sense of tempered distributions,where S is a bilinear operator bounded from H_(a)^(p)(r^(n))*L_(a)^(a)(r^(Φ_(p))) to L^(1)(r^(n)) and T is a bilinear operator bounded from H_(a)^(p)(r^(n))*L_(a)^(a)(r^(n)) to H_(a)^(Φ_(p))(r^(n)) .Moreover,this bilinear decomposition is sharp in the dual sense that any y■H_(a)^(Φ_(p))(r^(n)) that fits into the above bilinear decomposition should satisfy(L^(1)(r^(n))+y)*=(L^(1)(r^(n)+H_(a)^(Φ_(p))(r^(n))*.As applications,for any non-constant b∈L_(a)^(a)(r^(n)) and any sublinear operator T satisfying some mild bounded assumptions,we find the largest subspace of H_(a)^(p)(r^(n)),denoted by H_(a,b)^(p)(r^(n)),such that the commutator [b,T] is bounded from H_(a,b)^(p)(r^(n))to L^(1)(r^(n)).In addition,when T is an anisotropic CalderónZygmund operator,the boundedness of [b,T] from H_(a,b)^(p)(r^(n))to L^(1)(r^(n))(or to H_(a)^(1)(r^(n)) is also *** key of their proofs is the wavelet characterization of function spaces under consideration.

关键词： anisotropic Euclidean space bilinear decomposition Hardy space Campanato space Musielak-Orlicz Hardy space commutator wavelet

Improved Properties of Aromatic Polyamide Tape-casting Films

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2020年第12期38卷 1345-1354页

作者： Fu-Lin Liu Jjian-jun He Hai-Xia yang Shi-Yong yang Laboratory of Advanced Polymer Materials Institute of ChemistryChinese Academy of SciencesBejing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049 China

A convenient tape-casting method was applied to prepare high performance aromatic polyamide(PA)films based on Technora®.During the polycondensation,CaO was introduced to improve the solubility of the PA resin,and the generated halides were totally removed from the film via a simple water bath,without leaving any defects in PA *** factors of processing temperature and immersion time had been systematically investigated,and the experimental results demonstrated that both of them had impressive impacts on aggregation state and comprehensive properties of the PA *** was suggested that immersion in water for more than 1 min and baking below 300℃ for 10 min were the optimal conditions for the thermal,tensile,tear,and optical properties to be in the best *** resultant PA films integrated outstanding film-forming ability and excellent general performance,especially the tensile property and tear resistance.

关键词： Tape-casting Aromatic polyamide film Solubility Aggregation state Tensile property Tear resistance

The Iyengar Type Inequalities with Exact Estimations and the Chebyshev Central Algorithms of Integrals

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2005年第6期21卷 1361-1376页

作者： Xing Hua WANG Shi jun yang Department of Mathematics Zhejiang University Hangzhou 310028 P. R. China College of Mathematics and Information Science Wenzhou University Zheiianq 325200 P R China Department of Mathematics Hangzhou Normal College Hangzhou 310012 P. R. China

In this paper, both low order and high order extensions of the Iyengar type inequality are obtained. Such extensions are the best possible in the same sense as that of the Iyengar inequality. hzrthermore, the Chebyshev central algorithms of integrals for some function classes and some related problems are also considered and investigated.

关键词： Iyengar inequality Chebyshev center Best quadrature formula Best interpolation Nikol-skii type estimations

Construction of nonseparable orthonormal compactly supported wavelet bases for L^2(r^d)

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2012年第2期27卷 205-224页

作者： yang Shou-zhi LIN jun-hong Department of Mathematics Shantou UniversityShantou 515063China

Suppose M and N are two r×r and s×s dilation matrices,***ΓM andΓN represent the complete sets of representatives of distinct cosets of the quotient groups M-T Zr/Zr and N-T Zs/Zs,*** methods for constructing nonseparable Ω-filter banks from M-filter banks and N-filter banks are presented,where Ω is a（r＋s） ×（r＋s） dilation matrix such that one of its complete sets of representatives of distinct cosets of the quotient groups Ω-T Zr＋s/Zr＋s areΓΩ={[γT h,ζ T q] T：γh∈ΓM,ζq∈ΓN}.Specially,Ω can be [MΘ0N],whereΘis a r×s integer matrix with M-1Θbeing also an integer ***,if the constructed filter bank satisfies Lawton＇s condition,which can be easy to verify,then it generates an orthonormal nonseparable Ω-wavelet basis for L2（rr＋s）.Properties,including Lawton＇s condition,vanishing moments and regularity of the new Ω-filter banks or new Ω-wavelet basis are discussed ***,a class of nonseparable Ω-wavelet basis for L2（rr＋1） are constructed and three other examples are given to illustrate the *** particular,when M=N=2,all results obtained in this paper appeared in[1].

关键词： filter bank nonseparable orthonormal wavelet basis Lawton's condition vanishing moment regularity.

Constitutive modeling of compression behavior of TC4 tube based on modified Arrhenius and artificial neural network models

在线全文

学校读者我要写书评

暂无评论

rare Metals 2016年第2期35卷 162-171页

作者： Zhi-jun Tao He yang Heng Li jun Ma Peng-Fei Gao State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University

Warm rotary draw bending provides a feasible method to form the large-diameter thin-walled（LDTW）TC4 bent tubes, which are widely used in the pneumatic system of aircrafts. An accurate prediction of flow behavior of TC4 tubes considering the couple effects of temperature,strain rate and strain is critical for understanding the deformation behavior of metals and optimizing the processing parameters in warm rotary draw bending of TC4 tubes. In this study, isothermal compression tests of TC4 tube alloy were performed from 573 to 873 K with an interval of 100 K and strain rates of 0.001, 0.010 and0.100 s^（-1）. The prediction of flow behavior was done using two constitutive models, namely modified Arrhenius model and artificial neural network（ANN） model. The predictions of these constitutive models were compared using statistical measures like correlation coefficient（r）, average absolute relative error（AArE） and its variation with the deformation parameters（temperature, strain rate and strain）. Analysis of statistical measures reveals that the two models show high predicted accuracy in terms of r and AArE. Comparatively speaking, the ANN model presents higher predicted accuracy than the modified Arrhenius model. In addition, the predicted accuracy of ANN model presents high stability at the whole deformation parameter ranges, whereas the predictability of the modified Arrhenius model has some fluctuation at different deformation conditions. It presents higher predicted accuracy at temperatures of 573-773 K, strain rates of 0.010-0.100 s^（-1）and strain of 0.04-0.32, while low accuracy at temperature of 873 K, strain rates of 0.001 s^（-1）and strain of ***, the application of modified Arrhenius model is limited by its relatively low predicted accuracy at some deformation conditions, while the ANN model presents very high predicted accuracy at all deformation conditions,which can be used to study the compression behavior of TC4 tube at the temperature range of 573-

关键词： TC4 tube Compression behavior Constitutive model Modified Arrhenius model Neural network model

Accelerating sample preparation of graded thermoelectric materials using an automatic powder feeding system

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2019年第3期7卷 278-287页

作者： Hua-Yan Pu rong-Qing Xie Yan Peng yang yang Shi-yang He jun Luo Yi Sun Shao-rong Xie jun Luo School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444People's Republic of China School of Materials Science and Engineering Shanghai UniversityShanghai 200444People's Republic of China Materials Genome Institute Shanghai UniversityShanghai 200444People's Republic of China

In recent years,the development of techniques for the controlled preparation of functional graded materials(FGMs)has become a vigorous research *** this study,to improve the efficiency and accuracy of sample preparations,an automated feeding system based on gravimetric principles for dry powder with three dosing feeders is designed and *** feeding rate and accuracy can be regulated by coordinating the protruded length L(mm)and rotational speed V(r/min)of the feeder *** demonstrate this automatic sample preparation system,the well-known thermoelectric material BixSb2-x-Te3(x=0.3,0.4,0.5,0.6,0.7 and 0.8)is selected and prepared by the developed system,and the composition distribution of the functional graded material is *** results show that the BixSb2_xTe3(x=0.3-0.8)functionally graded material crystalizes in the rhombohedral phase after hot-pressing sintering and annealing and the prepared sample has a good gradient composition *** verifies the reliability and accuracy of the feeding *** concept of samples with a gradient component and application of the automatic powder feeding system could considerably accelerate the research and development of new materials.

关键词： Powder feeding Automatic system Functional graded material Thermoelectric

Pascal realization by Comb-Spectral-Interferometry Based refractometer

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2018年第10期35卷 85-88页

作者： Li-jun yang Yan Li State Key Laboratory of Precision Measurement Technology & Instruments Department of Precision InstrumentsTsinghua University

To break through the limitations of existing pressure standards, which rely on the gravity and toxic mercury,the national metrological institutes prefer a quantum-based pressure standard. Combining the ideal gas law with helium refractivity measurement, we demonstrate a scheme for the realization of the pressure unit. The refractometer is based on a spectral interferometry with an optical frequency comb and a double-spaced vacuum cell. Through fast Fourier transform of the spectral interferograms of the two beams propagating inside and outside the vacuum cell, the helium refractivity can be obtained with a combined standard uncertainty u（n） of2.9 × 10-9. Moreover, the final u（n） is -8.7 × 10-6 in a measurement range of several megapascals（MPa）. Our apparatus is compact, fast（15 ms for one single measurement） and easy to handle. Furthermore, the measurement uncertainty will be improved to-1 × 10-9 or lower if a VIPA-based spectrometer is used. The value of u（p） will thus increase to 3 × 10-6 or better in several MPa.

关键词： Pascal realization by Comb-Spectral-Interferometry Based refractometer