检索结果-南通市图书馆

Entanglement Concentration with Different Measurement in a 3-Mode Optomechanical System

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

Communications in Theoretical Physics 2017年第7期67卷 57-63页

作者： zhe li School of Physics University of Chinese Academy of Sciences P.O. Box 4588 Beijing 100049 China

In this work, we perform a series of phonon counting measurement with different methods in a 3-mode optomechanical system, and we compare the difference of the entanglement after measurement. In this article we focus on the three eases： prefect measurement, imperfect measurement and on-off measurement. We find that whatever measurement you take, the entanglement will increase. The size of entanglement enhancement is the largest in the perfect measurement, second in the imperfect measurement, and it is not obvious in the on-off measurement. We are sure that the more precise measurement information, the larger entanglement concentration.

关键词： entanglement concentration quantum measurement optomechanical system

Influence of a multi-step process on the thickness reduction error of sheet metal in a flexible rolling process

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2019年第1期26卷 76-85页

作者： Yi li Ming-zhe li Kai liu Dieless Forming Technology Center Roll Forging Institute Jilin University College of Materials Science and Engineering Jilin University

Flexible rolling is a forming process based on thickness reduction, and the precision of thickness reduction is the key factor affecting bending deformation. The major purpose of the present work is to solve the problem of bending deformation error caused by insufficient thickness reduction. Under the condition of different rolling reductions with the same sheet thickness and the same thickness reduction with different sheet thicknesses, the thickness reduction error of sheet metal is analyzed. In addition, the bending deformation of sheet metal under the same conditions is discussed and the influence of the multi-step forming process on the thickness reduction error is studied. The results show that, under the condition of the same sheet thickness, the thickness reduction error increases with increasing rolling reduction because of an increase in work hardening. As rolling reduction increases, the longitudinal bending deformation decreases because of the decrease of the maximum thickness difference. Under the condition with the same thickness reduction, the thickness reduction error increases because of the decrease of the rolling force with increasing sheet thickness. As the sheet thickness increases, the longitudinal bending deformation increases because of the increase in the maximum thickness difference. A larger bending deformation is divided into a number of small bending deformations in a multi-step forming process, avoiding a sharp increase in the degree of work hardening; the thickness reduction error is effectively reduced in the multi-step forming process. Numerical simulation results agree with the results of the forming experiments.

关键词： flexible rolling convex surface numerical simulation thickness reduction error multi-step forming process

Coulomb Screening and Plasmon Excitation in Graphene at Finite Temperature

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2009年第8期52卷 361-364页

作者： li Zhao-zhe School of Physics Peking University Beijing 100871 China

By using the random phase approximation (RPA) in many-body perturbation theory,we calculate thepolarization function of the electron gas in graphene at finite *** on this,we calculate the temperaturedependent dielectric function ∈(q).The thermal effect on ∈(q) in various q regions is *** temperaturedependence is found to be *** also investigate the plasmon dispersion relation at finite temperature,with thezero-temperature relation as a special *** result is in good agreement with recent experimental data.

关键词： graphene polarization function dielectric function plasmon

Effects of the Extract of Ammopiptanthus mongolicus cheng f. (JA1) on Induction of Apoptosis of HepG2 in vitro and Its Molecular Mechanisms

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2006年第2期19卷 118-123页

作者： LEI JIA li-zhe AN Key Laboratory of Arid and Pastoral Agroecology of Ministry of Education and School of life Sciences LanzhouUniversity Lanzhou 730000 Gansu China Key Laboratory of Desert and Desertification Cold and Arid Region Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 Gansu China

Objective To study the effects and the mechanisms of extract from a leguminous plant （Ammopiptanthus mongolicus cheng f.）（JAl ） in northwest China on inducing apoptosis and inhibiting proliferation of HepG2 hepatocarcinoma cell in vitro. Methods The HepG2 cell line was used as target cells. The effect of 3A 1 on HepG2 cell growth was detected by microculture tetrazolium assay （MTr）, flow cytometry assay, DNA agarose gel electrophoresis and transmission electronic microscopy. The expressive effect of the wt-p53 in HepG2 cells was analyzed with p53 protein test-reagent. Results JAl not only had significant anti-proliferative effects depending upon time and dosage, but also induced apoptosis of HepG2 cells. Apoptotic typical morphological changes were observed in JAl-treated HepG2 cells under transmission electronic microscope, ＂Sub-G 1＂ phase peak occurred in flow cytometry and DNA ＂ladder＂ was found in DNA agarose gel electrophoresis. The expression of the wt-p53 increased in vitro, and 3Al-treated HepG2 and the positive cell percentage of the wt-p53 protein also increased. Conclusions JAl could obviously induce apoptosis and inhibit proliferation of HepG2 cells in vitro, and these effects are closely related with the increase of wt-p53 expression. JAl can be used as a good source of medicinal plant for the treatment of hepatocarcinoma.

关键词： Extract from Ammopiptanthus mongolicus cheng f. (JAl) HepG2 Apoptosis Induction wt-p53

Review of characterization and modeling of polymer electrolyte fuel cell catalyst layer： The blessing and curse of ionomer

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2017年第3期11卷 334-364页

作者： Jun HUANG zhe li Jianbo ZHANG Department of Automotive Engineering State Key Laboratory of Automotive Safety and Energy Tsinghua University Beijing 100084 China College of Chemistry and Chemical Engineering Central South University Changsha 410083 China Beijing Co-innovation Center for Electric Vehicles Beijing Institute of Technology Beijing 100081 China

Ionomer impregnation represents a milestone in the evolution of polymer electrolyte fuel cell （PEFC） catalyst layers. Ionomer acts as the binder, facilitates proton transport, and thereby drastically improves catalyst utilization and effectiveness. However, advanced morpho- logical and functional characterizations have revealed that up to 60% of Pt nanoparticles can be trapped in the micropores of carbon support particles. Ionomer clusters and oxygen molecules can hardly enter into micropores, leading to low Pt utilization and effectiveness. Moreover, the ionomer thin-films covering Pt nanoparticles can cause significant mass transport loss especially at high current densities. Ionomer-free ultra-thin catalyst layers （UTCLs） emerge as a promising alternative to reduce Pt loading by improving catalyst utilization and effectiveness, while theoretical issues such as the proton conduction mechan- ism remain puzzling and practical issues such as the rather narrow operation window remain unsettled. At present, the development of PEFC catalyst layer has come to a crossroads： staying ionomer-impregnated or going iono- mer-free. It is always beneficial to look back into the past when coming to a crossroads. This paper addresses the characterization and modeling of both the conventional ionomer-impregnated catalyst layer and the emerging ionomer-free UTCLs, featuring advances in characterizing microscale distributions of Pt particles, ionomer, support particles and unraveling their interactions; advances in fundamental understandings of proton conduction and flooding behaviors in ionomer-free UTCLs; advances in modeling of conventional catalyst layers and especially UTCLs; and discussions on high-impact research topics in characterizing and modeling of catalyst layers.

关键词： polymer electrolyte fuel cell ultra-thin cata-lyst layer electrostatic interactions characterization andmodeling structure-property-performance relation watermanagement

Effects of cerium doping position on physicochemical properties and catalytic performance in methanol total oxidation

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

Journal of Rare Earths 2018年第8期36卷 811-818页

作者： Shen Zhang Yuyu Guo Xingying li zhe li College of Chemistry and Chemical Engineering Taiyuan University of Technology

The physicochemical properties of Pd and Pd-Pt catalysts which possess different Ce doping position were investigated by techniques of TEM, XRD, N2 adsorption-desorption, XPS and FT-IR. The catalytic performance for methanol total oxidation was examined to study the effects of Ce adding ***2-Al2 O3-TiO2（CAT） catalysts that Ce is directly introduced into support show higher reactivity and CO2 selectivity than CeO2/Al2 O3-TiO2（Ce/AT） samples in which Ce is loaded by impregnation *** characterization results reveal that the Ce doping position does not cause obvious otherness of basic crystalline phase and mesoporous structure of support. However, the Ce doping position affects the pore shapes of support and then influences the pore diameter. CAT catalysts possess more abundant adsorbed oxygen and more Ti3＋ can transform the more gaseous oxygen into the active oxygen species on the catalyst surface, which is beneficial to the reaction. The Al-O-Ti bridges in CAT facilitate the cooperation of Al and Ti species, which further speeds up the reaction rate.

关键词： Ce doping position Methanol total oxidation Adsorbed oxygen Al-O-Ti bridges Rare earths

Improving effect on forming quality and accuracy using a polyurethane board positioning/resetting the discrete steel pad in multi-point forming

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2019年第4期26卷 447-459页

作者： Er-hu Qu Ming-zhe li Rui li College of Materials Science and Engineering Jilin University Roll Forging Institute Jilin University Changchun Ruiguang Technology Co. Ltd.

To improve the quality of multi-point die forming, a new approach using discrete steel pads was proposed. The formability of three different multi-point die forming processes was analyzed through numerical simulation and experiments. Numerical simulation and experimental results showed that the use of discrete steel pads in the multi-point forming process can substantially improve the stress–strain state on the plate and suppress dimple, straight-edge, and wrinkle defects. This analysis verified that the use of discrete steel pads in a multi-point forming process can effectively improve the quality and accuracy with which sheet metal is formed.

关键词： multi-point forming dimple wrinkle numerical simulation forming accuracy

An Algorithm for the Discretization of an Ideal Projector

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2016年第5期29卷 1400-1410页

作者： JIANG Xue ZHANG Shugong li zhe Institute of Mathematics Key Laboratory of Symbolic Computation and Knowledge Engineering (Ministry of Education) Jilin University Department of Applied Mathematics School of Science Changchun University of Science and Technology

Ideal interpolation is a generalization of the univariate Hermite interpolation. It is well known that every univariate Hermite interpolant is a pointwise limit of some Lagrange ***, a counterexample provided by Shekhtman Boris shows that, for more than two variables,there exist ideal interpolants that are not the limit of any Lagrange interpolants. So it is natural to consider: Given an ideal interpolant, how to find a sequence of Lagrange interpolants(if any) that converge to it. The authors call this problem the discretization for ideal interpolation. This paper presents an algorithm to solve the discretization problem. If the algorithm returns "True", the authors get a set of pairwise distinct points such that the corresponding Lagrange interpolants converge to the given ideal interpolant.

关键词： Discretization ideal interpolation Lagrange interpolation.

Optimal Design of Two Road Networks Based on their Properties

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2007年第2期23卷 337-352页

作者： Ming-zhe li Yan Zhang Faculty of Economics Fukuoka University 8-19-1 Nanakuma Jonan-ku Fukuoka 814-0180 Japan

In this paper, we discuss some fundamental properties of two idealized typical networks, namely, grid type and radial-circular type. The discussion is based on SPCP （Shortest Path Counting Problem）, which reflects the traffic density of a road segment. Furthermore, we compare their effectiveness based on the obtained results of the above two road networks, and suggest some proposals on the design of car lanes by considering the direction of a road segment in relation to these road networks.

关键词： SPCP DSPCP grid radial-circular optimal design of road networks