检索结果-南通市图书馆

May 2022 Greedy Kaczmarz Algorithm Using Optimal Intermediate Projection Technique for Coherent Linear Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,Methods and Applications) 2022年第2期15卷 464-483页

作者： Fang Geng Li-Xiao Duan guo-feng zhang School of Mathematics and Statistics Lanzhou UniversityLanzhou 730000China

The Kaczmarz algorithm is a common iterative method for solving linear *** an effective variant of Kaczmarz algorithm,the greedy Kaczmarz algorithm utilizes the greedy selection *** two-subspace projection method performs an optimal intermediate projection in each *** this paper,we introduce a new greedy Kaczmarz method,which give full play to the advantages of the two improved Kaczmarz algorithms,so that the generated iterative sequence can exponentially converge to the optimal *** theoretical analysis reveals that our algorithm has a smaller convergence factor than the greedy Kaczmarz *** results confirm that our new algorithm is more effective than the greedy Kaczmarz method for coherent systems and the two-subspace projection method for appropriate scale systems.

关键词： Kaczmarz algorithm two-subspace greedy methods linear systems

An Inertial Semi-forward-reflected-backward Splitting and Its Application

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2022年第2期38卷 443-464页

作者： Chun Xiang ZONG Yu Chao TANG guo feng zhang School of Mathematics and Statistics Lanzhou UniversityLanzhou 730000.P.R.China Department of Mathematics Nanchang UniversityNanchang 330031P.R.China

Inertial methods play a vital role in accelerating the convergence speed of optimization *** work is concerned with an inertial semi-forward-reflected-backward splitting algorithm of approaching the solution of sum of a maximally monotone operator,a cocoercive operator and a monotone-Lipschitz continuous *** theoretical convergence properties of the proposed iterative algorithm are also presented under mild *** importantly,we use an adaptive stepsize rule in our algorithm to avoid calculating Lipschitz constant,which is generally unknown or difficult to estimate in practical *** addition,a large class of composite monotone inclusion problem involving mixtures of linearly composed and parallel-sum type monotone operators is solved by combining the primal-dual approach and our proposed *** a direct application,the obtained inertial algorithm is exploited to composite convex optimization problem and some numerical experiments on image deblurring problem are also investigated to demonstrate the efficiency of the proposed algorithm.

关键词： Operator splitting inertial scheme composite monotone inclusions composite convex optimization total variation

Dense coding capacity in correlated noisy channels with weak measurement

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第11期30卷 196-201页

作者： Jin-Kai Li Kai Xu guo-feng zhang School of Physics Beihang UniversityBeijing 100191China

Capacity of dense coding via correlated noisy channel is greater than that via uncorrelated noisy *** is shown that the weak measurement and reversal measurement need to further improve their quantum dense coding capacity in correlated amplitude damping channel,but this improvement is very small in correlated phase damping channel and correlated depolarizing channel.

关键词： correlated noise channel quantum dense coding weak measurement reversal measurement

STABILITIES OF (A,B,C) AND NPDIRK METHODS FOR SYSTEMS OF NEUTRAL DELAY-DIFFERENTIAL EQUATIONS WITH MULTIPLE DELAYS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2003年第3期21卷 375-382页

作者： guo-feng zhang (Department of Mathematics, Lanzhou University, Lanzhou 730000, China) Department of Mathematics Lanzhou University Lanzhou 730000

Consider the following neutral delay-differential equations with multiple delays (NMDDE)where γ> 0, L, Mj and Nj are constant complex- value d×d matrices. A sufficient condition for the asymptotic stability of NMDDE system (0.1) is given. The stability of Butcher's (A,B,C)-method for systems of NMDDE are studied. In addition, we present a parallel diagonally-implicit iteration RK (PDIRK) methods(NPDIRK) for systems of NMDDE, which is easier to be implemented than fully implicit RK methods. We also investigate the stability of a special class of NPDIRK methods by analyzing their stability behaviors of the solutions of (0.1).

关键词： Neutral delay differential equations (A,B,C)-method RK method Parallel diagonally-implicit iteration RK method.

Charging and self-discharging process of a quantum battery in composite environments

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2023年第3期18卷 203-214页

作者： Kai Xu Han-Jie Zhu Hao Zhu guo-feng zhang Wu-Ming Liu School of Science Tianjin University of TechnologyTianjin 300384China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physics Beihang UniversityBeijing 100191China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

How to improve charging processes and suppress self-discharging processes has always been one of the key issues to achieve quantum batteries with high *** a quantum battery is inevitably influenced by composite environments,this situation is still little understood,particularly regarding the influence of the memory effect of the composite environments and the coupling between composite *** this work,we investigate the effects of the composite environments,composed of two identical parts each containing a single cavity mode decaying to a reservoir,on the charging and self-discharging processes of a quantum *** show that increasing the two-mode coupling can effectively enhance the charging performance(i.e.,the stored energy,the charging power,ergotropy)and restrain the self-discharging process(i.e.,suppressing the process of dissipating the energy).However,different from the effect of two-mode coupling,we reveal that the memory effect of the reservoir in this composite environment is unfavorable to the charging process of the quantum battery,which is in sharp contrast to previous studies where the memory effect can significantly improve the charging performance of a quantum *** results may benefit to the realization of quantum batteries with high performance under the actual complex environmental noise.

关键词： quantum battery quantum device

Responses of bacterial strains isolated from drinking water environments to N-acyI-L-homoserine lactones and their analogs during biofilm formation

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2014年第2期8卷 205-214页

作者： Zhuoying WU1 Qing WANG, feng guo Shenghua zhang Qipei JIANG Xin YU Key Laboratory of Urban Environment and Health Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 China

Often as a result ofbiofilm formation, drinking water distribution systems （DWDS） are regularly faced with the problem of microbial contamination. Quorum sensing （QS） systems play a marked role in the regulation of microbial biofilm formation; thus, inhibition of QS systems may provide a promising approach to biofilm formation control in DWDS. In the present study, 22 bacterial strains were isolated from drinking water-related environments. The following properties of the strains were investigated： bacterial biofilm formation capacity, QS signal molecule N-acyl-L-homoserine lactones （AHLs） production ability, and responses to AHLs and AHL analogs, 3-chloro-4-（dichloromethyl）-5-hydroxy-2（5H）- furanone （MX） and 2（5H）-furanone. Four AHLs were added to developed biofilms at dosages ranging from 0.1 nmol.L J to 100nmol.L1. As a result, the biofilm growth of more than 1/4 of the isolates, which included AHL producers and non-producers, were significantly promoted. Further, the biofilm biomasses were closely associated with respective AHLs concentrations. These results provided evidence to support the idea that AHLs play a definitive role in biofilm formation in many of the studied bacteria. Meanwhile, two AHLs analogs demon- strated unexpectedly minimal negative effects on biofilm formation. This suggested that, in order to find an applicable QS inhibition approach for biofilm control in DWDS, the testing and analysis of more analogs is needed.

关键词： drinking water distribution systems (DWDS) biofilm quorum sensing (QS) N-acyl-L-homoserine lac- tones (AHLs) (dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) 2(5H)-furanone

Modification of single molecule fluorescence using external fields

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2017年第5期12卷 11-25页

作者： Rui-Yun Chen guo-feng zhang Cheng-Bin Qin Yan Gao Lian-Tuan Xiao Suo-Tang Jia State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser Spectroscopy Shanxi University Taiyuan 030006 China Collaborative Innovation Center of Extreme Optics S hanxi University Taiyuan 030006 China

Controlling and manipulating the fluorescence of single fluorophores is of great interest in recent years for its potential uses in improving the performance of molecular photonics and molecular electronics, such as in organic light-emitting devices, single photon sources, organic field-effect transistors, and probes or sensors based on single molecules. This review shows how the fluorescence emission of single organic molecules can be modified using local electromagnetic fields of metallic nanostructures and electric-field-induced electron transfer. Electric-field-induced fluorescence modulation, hysteresis, and the achievement of fluorescence switch are discussed in detail.

关键词： single molecules fluorescence modification external fields

Synthesis of Fluorene-Bridged Arylene Vinylene Fluorophores： Effects of End-Capping Groups on the Optical Properties, Aggregation Induced Emission

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 Journal of Chemistry 2015年第8期33卷 939-947页

作者： guo-feng zhang Tao Chen Ze-Qiang Chen Matthew P. Aldred Xianggao Meng Ming-Qiang Zhu Wuhan National Laboratory for Optoelectronics School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan Hubei 430074 China Department of Chemistry Durham University South Road Durham DH1 3LE UK Key Laboratory of Pesticide and Chemical Biology of Ministry of Education College of Chemistry Central China Normal University Wuhan Hubei 430079 China

We have synthesized a series of fluorene-based fluorophores, in which a central fluorene core has been modified with different peripheral arylene vinylene substituents that are able to activate aggregation-induced emission （AIE） characteristics. 9,9-Dioctylfluorene doubly end-capped at the 2,7-positions with triphenylethene groups, such as 4-（2,2-diphenylvinyl）phenyl （F1-（2,2）-HTPE） and 4-（1,2-dipbenylvinyl）phenyl （F1-（1,2）-HTPE） were synthesized and compared to the tetraphenylethene analogue （F1-TPE）. Both FI-（2,2）-HTPE and F1-（1,2）-HTPE glow with a deep blue fluorescence in THF solution with emission maxima （λem） of 426 and 403 nm, respectively. The λem slightly red-shifts in the solid-state to 458 nm for F 1-（2,2）-HTPE and 437 nm for F 1-（1,2）-HTPE. The fluorescence quantum yields （ΦF） of F1-（2,2）-HTPE （ΦF=35.1%） and FI-（1,2）-HTPE （ΦF=26.2%） were found to be higher in solution compared to the near quenching of F 1-TPE （ΦF = 0.1%）. Consequently, this results in weaker AIE-stability of F1-（2,2）-HTPE （αAIE= 1.5） and F1-（1,2）-HTPE （αAIE=1.9） compared to F1-TPE （αAIE=125）, suggesting that four phenyl groups are necessary for efficient AIE-activity of these fluorene bridged arylene vinylene type materials In addition, decreasing the steric hindrance around the arylene vinylene moiety by removal of a phenyl ring is an- other method to decrease the AIE characteristics, in a similar manner to the commonly known ＂phenyl-locking＂. Non-polar triphenylethenes are poorer AlE materials than their tetraphenylethene analogues. Replacing the hydro- gen atom of F1-（2,2）-HTPE with a cyano group affords fluorene end-capped with 2,3,3-triphenylacrylonitrile （F1-TPAN）, which boosts the AIE-effect to αAIE=90.5 and red-shifts the solid-state emission （λem=528 nm） with near quenching in THF solution （ΦF= 0.12%）. X-ray crystallographic analysis of F1-TPAN indicates that the intro- duction of cyano groups can not only diminish the intramolecular steric hindrance in comparison of F1-TPE, but

关键词： aggregation-induced emission fluorene triphenylethene tetraphenylethene 2,3,3-triphenylacrylonitrile

Study on the influence of curcumin on chemosensitivity of nephroblastoma cells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2016年第8期9卷 779-782页

作者： Xiao-Yong Li Yuan-Yuan feng Wei Dan Deng Pan guo-feng zhang Xian-Liang Wang Guang-Jun Hou Department of Pediatric Surgery Children's Hospital of Zhengzhou Department of Paediatrics Children's Hospital of Zhengzhou Department of Paediatrics Maternal and Child Health Hospital of Tonglu County

Objective:To study the influence of curcumin on chemosensitivity of nephroblastoma ***:Human nephroblastoma cells line SK-NEP-1 was transplanted to the nude mice subcutaneously to establish the implantation tumor model of human nephroblastoma cells.A total of 30 tumor-bearing mice were divided into three groups of ten *** routine chemotherapy group was given vincristine(0.05 mg/mL·0.2 mL/d) and actinomycin D(15 ng/mL·0.2 mL/d) combined chemotherapy *** curcumin chemotherapy group was given the same combined chemotherapy regimens and curcumin(30 mg/kg/d) by intraperitoneal *** control group was given normal saline(NS) of the same volume by intraperitoneal *** administration would be kept for 4 weeks and 3 days a *** volumetric changes of every group were *** serum of every group in different time was collected and the VEGF content was detected by *** mice were cercrificed and the tumor tissues were stripped and weighed after 4 weeks’ *** tumor inhibition rate was *** cell proliferation activity and apoptosis rate were detected by MTT and flow cytometry *** data were statistically analyzed by SPSS ***:The tumor volume,serum VEGF content,tumor inhibition rate,cell proliferation activity and apoptosis rate of routine chemotherapy group and curcumin chemotherapy group had significant differences comparing with the control group(P<0.05) after 4-week’s *** cancer growth of curcumin chemotherapy group was obviously decreased and even tended to shrink comparing with routine chemotherapy group(χ2=15.732,P=0.007).The cell proliferation activity was significantly reduced and the apoptosis rate was significantly higher,(χ~2=9.427,P=0.012)which showing the effect of chemotherapy was ***:The chemosensitivity of nephroblastoma cells could be improved by curcumin,then the effect of preoperative adjuvant chemotherapy scheme would be enhanced,the gro

关键词： Nephroblastoma Transplanted tumor model Curcumin Chemosensitivity Vincristine