检索结果-南通市图书馆

Science China Mathematics 2021年第3期64卷 519-546页

作者： Yuan zhao Haibo Lin Yan meng College of Science China Agricultural UniversityBeijing 100083China School of Mathematics Renmin University of ChinaBeijing 100872China

Let(X, d, μ) be a non-homogeneous metric measure space satisfying the so-called upper doubling and geometrically doubling conditions, which includes the space of homogeneous type and the Euclidean space with the non-doubling measure as special cases. Let T be a multilinear Calderón-Zygmund operator and b:=(b1,..., bm) be a finite family of RBMO(μ) functions. In this paper, some weak-type multiple weighted estimates for the iterated commutator T∏bgenerated by T and b are obtained.

关键词： non-homogeneous metric measure space multiple weight commutator multilinear Calderón-Zygmund operator

Key Parameters Analysis and Regulation of singlet Oxygen Quenching Rate of Carotenoids

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2020年第7期39卷 1226-1234页

作者： zhao Kai JIANG Wei meng Chong Education Academy Beijing Sport UniversityBeijing 100084China School of Environment Beijing Normal UniversityBeijing 100875China

28 kinds of carotenoids are studied to reveal the key parameters and regulation on the singlet oxygen quenching ***,the quantum chemistry parameters of carotenoids calculated by Gaussian software combined with substitution parameters were used to construct the quantitative structure-activity relationship model(QSAR)of the singlet oxygen quenching rate of *** key parameters affecting the antioxidant activity of carotenoids are revealed,and the data predicted via the QSAR model were provided for subsequent ***,a three-dimensional(3D)pharmacophore model was used to regulate and modify the antioxidant activity of *** correlation coefficients of the modeling group(R2)and verification group(Rpre2)of the established QSAR model were 0.945 and 0.916,respectively,which can be used for the analysis of antioxidant activity of carotenoids;the antioxidant activity of carotenoids can be significantly regulated by the number of conjugated C=C bonds,the energy difference between frontier molecular orbitals and the partial Mulliken charge in C1 and theπ···π*excitation energy E(s);the antioxidant activity of carotenoids can be effectively regulated by the hydrogen bond acceptor pharmacophores on both sides of the conjugated C=C bonds and the hydrophobic groups on the conjugated C=C bond;the hydrophobic substituents attached to conjugated C=C bonds can effectively improve the singlet oxygen quenching rate of carotenoids.

关键词： carotenoids singlet oxygen quenching quantitative structure-activity relationship model 3D pharmacophore model parameters analysis

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2016年第3期17卷 212-223页

作者： Xiao-hu MA meng YANG zhao ZHANG School of Computer Science and Technology Soochow University State Key Laboratory for Novel Software Technology Nanjing University

The feature extraction algorithm plays an important role in face recognition. However, the extracted features also have overlapping discriminant information. A property of the statistical uncorrelated criterion is that it eliminates the redundancy among the extracted discriminant features, while many algorithms generally ignore this property. In this paper, we introduce a novel feature extraction method called local uncorrelated local discriminant embedding(LULDE). The proposed approach can be seen as an extension of a local discriminant embedding(LDE)framework in three ways. First, a new local statistical uncorrelated criterion is proposed, which effectively captures the local information of interclass and intraclass. Second, we reconstruct the affinity matrices of an intrinsic graph and a penalty graph, which are mentioned in LDE to enhance the discriminant property. Finally, it overcomes the small-sample-size problem without using principal component analysis to preprocess the original data, which avoids losing some discriminant information. Experimental results on Yale, ORL, Extended Yale B, and FERET databases demonstrate that LULDE outperforms LDE and other representative uncorrelated feature extraction methods.

关键词： Feature extraction Local discriminant embedding Local uncorrelated criterion Face recognition

Rock deformation equations and application to the study on slantingly installed disc cutter

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica sinica 2014年第4期30卷 540-546页

作者： zhao-Huang Zhang Liang meng Fei Sun School of Energy Power and Mechanical EngineeringNorth China Electric Power University School of Foreign Languages North China Electric Power University

At present the mechanical model of the interac- tion between a disc cutter and rock mainly concerns indentation experiment, linear cutting experiment and tunnel boring machine （TBM） on-site data. This is not in line with the actual rock-breaking movement of the disc cutter and impedes to some extent the research on the rock-breaking mechanism, wear mechanism and design theory. Therefore, our study focuses on the interaction between the slantingly installed disc cutter and rock, developing a model in accordance with the actual rock-breaking movement. Displacement equations are established through an analysis of the velocity vector at the rock-breaking point of the disc cutter blade; the func- tional relationship between the displacement parameters at the rock-breaking point and its rectangular coordinates is established through an analysis of micro-displacement vectors at the rock-breaking point, thus leading to the geometric equations of rock deformation caused by the slantingly installed disc cutter. Considering the basically linear relationship between the cutting force of disc cutters and the rock deformation before and after the leap break of rock, we express the constitutive relations of rock deformation as generalized Hooke＇s law and analyze the effect of the slanting installa- tion angle of disc cutters on the rock-breaking force. This will, as we hope, make groundbreaking contributions to the development of the design theory and installation practice of TBM.

关键词： TBM Disc cutter· Geometric equation Slant-ingly installed Rock-breaking

The comparative analysis of rocks' resistance to forward-slanting disc cutters and traditionally installed disc cutters

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica sinica 2016年第4期32卷 690-695页

作者： zhao-Huang Zhang Sun Fei meng Liang School of Energy Power and Mechanical EngineeringNorth China Electric Power University School of Foreign Languages North China Electric Power University

At present, disc cutters of a full face rock tunnel boring machine are mostly mounted in the traditional way. Practical use in engineering projects reveals that this installation method not only heavily affects the operation life of disc cutters, but also increases the energy consumption of a full face rock tunnel boring machine. To straighten out this issue, therefore, a rock-breaking model is developed for disc cutters＇ movement after the research on the rock breaking of forward-slanting disc cutters. Equations of its displacement are established based on the analysis of velocity vector of a disc cutter＇s rock-breaking point. The functional relations then are brought forward between the displacement parameters of a rock-breaking point and its coordinate through the analysis of micro displacement of a rock-breaking point. Thus, the geometric equations of rock deformation are derived for the forward-slanting installation of disc cutters. With a linear relationship remaining between the acting force and its deformation either before or after the leap breaking, the constitutive relation of rock deformation can be expressed in the form of generalized Hooke law, hence the comparative analysis of the variation in the resistance of rock to the disc cutters mounted in the forward-slanting way with that in the traditional way. It is discovered that with the same penetration, strain of the rock in contact with forwardslanting disc cutters is apparently on the decline, in otherwords, the resistance of rock to disc cutters is reduced. Thus wear of disc cutters resulted from friction is lowered and energy consumption is correspondingly decreased. It will be useful for the development of installation and design theory of disc cutters, and significant for the breakthrough in the design of full face rock tunnel boring machine.

关键词： installed breaking installation rock apparently tunnel traditionally decline remaining brought

Leptin gene-targeted editing in ob/ob mouse adipose tissue based on the CRISPR/Cas9 system

在线全文

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2021年第2期48卷 134-146页

作者： Lin Zhu Xiaoyan Yang Juyi Li Xiong Jia Xiangli Bai Ying zhao Wenzhuo Cheng meng Shu Yan Zhu si Jin Department of Endocrinology Institute of Geriatric MedicineLiyuan HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Department of Pediatrics Tongji HospitalTongji Medicine CollegeHuazhong University of Science and TechnologyWuhan 430030China Department of Pharmacology Hubei Key Laboratory of Drug Target Research and Pharmacodynamic EvaluationSchool of Basic MedicineTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Department of Pharmacy The Central Hospital of WuhanTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Department of Laboratory Medicine Liyuan HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

Gene therapy has become the most effective treatment for monogenic *** LEPTIN deficiency is a rare autosomal recessive monogenic obesity syndrome caused by mutations in the Leptin ***/ob mouse is a monogenic obesity model,which carries a homozygous point mutation of C to T in Exon 2 of the Leptin ***,we attempted to edit the mutated Leptin gene in ob/ob mice preadipocytes and inguinal adipose tissues using CRISPR/Cas9 to correct the C to T mutation and restore the production of LEPTIN protein by *** edited preadipocytes exhibit a correction of 5.5%of Leptin alleles and produce normal LEPTIN protein when differentiated into mature *** ob/ob mice display correction of 1.67%of Leptin alleles,which is sufficient to restore the production and physiological functions of LEPTIN protein,such as suppressing appetite and alleviating insulin *** study suggests CRISPR/Cas9-mediated in situ genome editing as a feasible therapeutic strategy for human monogenic diseases,and paves the way for further research on efficient delivery system in potential future clinical application.

关键词： CRISPR/Cas9 Gene editing Leptin Monogenetic disease Obesity

Low-dimensional non-metal catalysts:principles for regulating p-orbital-dominated reactivity

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 1699-1732页

作者： si Zhou Wei Pei Yanyan zhao Xiaowei Yang Nanshu Liu Jijun zhao Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Dalian University of Technology)Ministry of EducationDalian 116024China

Activation of p-block elements to replace the rare and precious transition metals for renewable energy applications is highly *** this review,we go over recent experimental and theoretical progress on the low-dimensional non-metal materials for clean energy production,including carbon,silicon,oxide,boron,and phosphorus-based nanostructures,with the p-block elements serving as active *** aim to elucidate the mechanism for triggering activity in different kinds of non-metal systems,and extract general principles for controlling the p-orbital-mediated reactivity from a theoretical point of *** perspectives and challenges for developing high-efficiency non-metal catalysts are provided in the end.

关键词： reactivity orbital principles

Numerical Optimization on Aerodynamic/Stealth Characteristics of Airfoil Based on CFD/CEM Coupling Method

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

Transactions of Nanjing University of Aeronautics and Astronautics 2016年第3期33卷 274-284页

作者： Jiang Xiangwen zhao Qijun zhao Guoqing meng Chen National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics Nanjing University of Aeronautics and Astronautics

Based on computational fluid dynamics （CFD）/computational eleetromagnetics method （CEM） coupling method and surrogate model optimization techniques, an integration design method about aerodynamic/stealth characteristics of airfoil is established. The O-type body-fitted and orthogonal grid around airfoil is first generated by using the Poisson equations, in which the points per wave and the normal range satisfy the aerodynamic and electromagnetic calculation accuracy requirement. Then the aerodynamic performance of airfoil is calculated by sol- ving the Navier-Stokes （N-S） equations with Baldwin-Lomax （B-L） turbulence model. The stealth characteristics of airfoil are simulated by using finite volume time domain （FVTD） method based on the Maxwell＇s equations, Steger-Warming flux splitting and the third-order MUSCL scheme. In addition, based upon the surrogate model optimization technique with full factorial design （FFD） and radial basis function （RBF）, an integration design about aerodynamic/stealth characteristics of rotor airfoil is conducted by employing the CFD/CEM coupling meth- od. The aerodynamic/stealth characteristics of NACA series airfoils with different maximum thickness and camber combinations are discussed. Finally, by choosing suitable lift-to-drag ratio and radar cross section （RCS） ampli- tudes of rotor airfoil in four important scattering regions as the objective function and constraint, the compromised airfoil with high lift-to-drag ratio and low scattering characteristics is designed via systemic and comprehensive ana- lyses.

关键词： rotor airfoil aerodynamic characteristics stealth characteristics CFD/CEM coupling surrogate modle

Empirical Likelihood Inference for Functional Coefficient ARCH-M Model

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica sinica,English Series 2019年第2期35卷 270-296页

作者： Hai Qing zhao Yuan LI Yan meng zhao School of Mathematics and Information Science Guangzhou University School of Mathematics and Statistics Lingnan Normal University School of Economics and Statistics Guangzhou University School of Mathematics and Statistics Shenzhen University

Empirical likelihood inference for parametric and nonparametric parts in functional coefficient ARCH-M models is investigated in this paper. Firstly, the kernel smoothing technique is used to estimate coefficient function δ(x). In this way we obtain an estimated function with parameter β.Secondly, the empirical likelihood method is developed to estimate the parameter β. An estimated empirical log-likelohood ratio is proved to be asymptotically standard chi-squred, and the maximum empirical likelihood estimation(MELE) for β is shown to be asymptotically normal. Finally, based on the MELE of β, the empirical likelihood approach is again applied to reestimate the nonparametric part δ(x). The empirical log-likelohood ratio for δ(x) is proved to be also asymptotically standard chi-squred. simulation study shows that the proposed method works better than the normal approximation method in terms of average areas of confidence regions for β, and the empirical likelihood confidence belt for δ(x) performs well.

关键词： ARCH-M model empirical likelihood relative risk aversion

Behavior of phase transformation of Baotou mixed rare earth concentrate during oxidation roasting

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2022年第6期40卷 981-987,I0005页

作者： Deliang meng meng Wang Zongyu Feng Chao Xia Yanyan zhao Xiaowei Huang School of Metallurgy Northeastern UniversityShenyang 110819China National Engineering Research Center for Rare Earth Materials GRINM Group Co.Ltd.Beijing 100088China General Research Institute for Nonferrous Metals Beijing 100088China GRIREM Advanced Materials Co. Ltd.Beijing 100088China

Based on the new process named "Combination Method" for metallurgy and separation of Baotou mixed rare earth concentrate(BMREC),the aim of this paper is to clearly elucidate the phase change behavior of BMREC without additives during oxidative roasting at 450-800℃.The results indicate that the bastnaesite in BMREC is decomposed at 450-550℃,the weight loss is about 10.3 wt%,and the activation energy(E) is 144 kJ/*** bastnaesite in BMREC is decomposed into rare earth fluoride,rare earth oxides(La_(2)O_(3),Ce_(7)O_(12),Pr_(6)O_(11) and Nd_(2)O_(3)),and CO_(2),particularly,with the increase of roasting temperature,bastnaesite in BMREC is more completely decomposed into LaF_(3),which causes a decrease in leaching rate of La during the HCI leaching ***,the maximum cerium oxidation efficiency reaches about 60 wt% when the roasting temperature is equal to or above 500℃,and the oxidation reaction rate of cerium increases with the increasing roasting temperature.

关键词： Phase change Combination method Oxidation roasting Cerium oxidation efficiency Rare earths