检索结果-南通市图书馆

The Research on Handoff Strategy in Beyond 3G Wireless Networks

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

The Journal of China Universities of Posts and Telecommunications 2006年第2期13卷 26-30页

作者： CUI Hong-yan TIAN Hui xu Hai-bo zhang Ping College of Telecommunication Engineering Beijing University of Posts and Telecommunications Beijing 100876 P.R. China

One of the major challenges for beyond third generation mobile .systems is efficient mobility management. This paper proposes a distributed dynamic management .scheme of handoff based on B3G networks. This scheme can reduce the cost of update signalling and transmitting packets, and improve the system capability. In this scheme, the dynamic building network approach is adopted to deduce the update signalling cost. We implement the distributed dynamic management scheme of handoff in a simulation platform and compare its performance with that of general centralized handoff management schemes. Our simulation results indicate that our scheme is capable of reducing the update handoff latency, and enhancing the performance.

关键词： B3G IPv6 handoff AP CA

Flexible manipulation of Omb levels in the endogenous expression region of Drosophila wing by combinational overexpression and suppression strategy

在线全文

学校读者我要写书评

暂无评论

Insect Science 2020年第1期27卷 14-21页

作者： xu-bo zhang Wei Dong Kai-Xia Li Juan-Juan Wang Jie Shen Bernard Moussian Jian-Zhen zhang Institute of Applied Biology College of Life ScienceShanxi UniversityTaiyuanChina Department of Entomology China Agricultural UniversityBeijingChina Applied Zoology Technical University DresdenZellescher Weg 20bDresdenGermany iBV University of Nice Sophia-AntipolisParc ValroseNiceFrance

Manipulating an exogenous or endogenous gene of interest at a defined level is critical for a wide variety of *** Gal4/UAS system has been widely used to direct gene expression for studying complex genetic and biological problems in Drosophila melanogaster and other model *** by a given tissue-specific Gal4,expressing UAS-transgene or UAS-RNAi(RNA interference)could be used to up-or down-regulate target gene expression,***,the efficiency of the Gal4/UAS system is roughly predefined by properties of transposon vector constructs and the insertion site in the transgenic ***,we describe a simple way to modulate optomotor blind(omb)expression levels in its endogenous expression region of the wing *** co-expressed UAS-omb and UAS-omb-RNAi together under the control of dpp-Gal4 driver which is expressed in the omb expression region of the wing *** repression effect is more sensitive to temperature than that of *** low temperature,overexpression plays a dominant role but the efficiency is attenuated by *** contrast,at high temperature RNAi predominates in gene expression *** this strategy,we could manipulate omb expression levels at a moderate *** allows us to manipulate omb expression levels in the same tissue between overexpression and repression at different stages by temperature control.

关键词： combinational expression Drosophila expression level Gal4/UAS system omb wing disc

Efficacy of endoscopic therapy for gastrointestinal bleeding from Dieulafoy’s lesion

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

World Journal of Gastroenterology 2011年第10期17卷 1368-1372页

作者： Jun Cui Liu-Ye Huang Yun-Xiang Liu bo Song Long-Zhi Yi Ning xu bo zhang Cheng-Rong Wu Department of Gastroenterology Yantai Yu Huang Ding Hospital Yantai 264000 Shandong Province China

AIM： To investigate the endoscopic hemostasis for gastrointestinal bleeding due to Dieulafoy＇s lesion. METHODS： One hundred and seven patients with gastrointestinal bleeding due to Dieulafoy＇s lesion were treated with three endoscopic hemostasis methods： aethoxysklerol injection （46 cases）, endoscopic hemoclip hemostasis （31 cases）, and a combination of hemoclip hemostasis with aethoxysklerol injection （30 cases）. RESULTS： The rates of successful hemostasis using the three methods were 71.7% （33/46）, 77.4% （24/31） and 96.7% （29/30）, respectively, with significant differences between the methods （P 〈 0.05）. Among those who had unsuccessful treatment with aethoxysklerol injection, 13 were treated with hemoclip hemostasis and 4 underwent surgical operation; 9 cases were successful in the injection therapy. Among the cases with unsuccessful treatment with hemoclip hemostasis,7 were treated with injection of aethoxysklerol and 3 cases underwent surgical operation; 4 cases were successful in the treatment with hemoclip hemostasis. Only 1 case had unsuccessful treatment with a combined therapy of hemoclip hemostasis and aeth- oxysklerol injection, and surgery was then performed. No serious complications of perforation occurred in the patients whose bleeding was treated with the endoscopic hemostasis, and no releeding was found during a 1-year follow-up. CONCLUSION： The combined therapy of hemoclip hemostasis with aethoxysklerol injection is the most effective method for gastrointestinal bleeding due to Dieulafoy＇s lesion.

关键词： Dieulafoy's lesion Gastrointestinal bleeding Endoscopic therapy Aethoxysklerol Therapeutic efficacy

△-tame quasi-hereditary algebras

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

Science China Mathematics 2007年第2期50卷 240-252页

作者： Yun-ge xu & Ying-bo zhang Faculty of Mathematics and Computer Science, Hubei University, Wuhan 430062, China School of Mathematics Sciences, Beijing Normal University, Beijing 100875, China Faculty of Mathematics and Computer Science Hubei University Wuhan China School of Mathematics Sciences Beijing Normal University Beijing China

Let (K, M,H) be an upper triangular bimodule problem. Briistle and Hille showed that the opposite algebra A of the endomorphism algebra of a projective generator P of the matrices category of (K., M, H) is quasi-hereditary, and there is an equivalence between the category of△-good modules of A and Mat(K, M). In this note, based on the tame theorem for bimodule problems, we show that if the algebra A associated with an upper triangular bimodule problem is of△-tame representation type, then the category F(△) has the homogeneous property, i.e. almost all modules in F(△) are isomorphic to their Auslander-Reiten translations. Moreover, if (K, M,H)is an upper triangular bipartite bimodule problem, then A is of△-tame representation type if and only if F(△) is homogeneous.

关键词： bimodule problem quasi-hereditary algebra △-tameness homogeneity.

Analysis for the axial force exerted on a micro-particle in the optical vortex

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2007年第6期3卷 477-480页

作者： WU Fu-yan WANG Yu-gang xu Jian-bo zhang Min LI Jie DOU Hui-qing ZHU Zhan-shou College of Physics and Electronics Shandong Normal University Ji＇ nan 250014 China

The axial force exerting to a micro-particle in the TEM01＊ doughnut mode is calculated by using the ray-optic model. The calculated results show that the optical vortex possesses two advantages in trapping the high-index micro-particles compared with that of the conventional optical tweezers,of which one is the axial f（ rce induced by the optical vortex and is three times as great as that of the optical tweezers under the. same power level, and the other is of two equilibrium positions in the optical vortex, which indicates that optical vortex is more suitable in trapping particles. Furthermore, the optical vortex can trap the low-index micro-particles, which can not by the conventional optical tweezers.

关键词：非线性光学光学旋涡粒子物理

Targets capture by distributed active swarms via bio-inspired reinforcement learning

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 210-221页

作者： Kun xu Yue Li Jun Sun Shuyuan Du Xinpeng Di Yuguang Yang bo Li Institute of Biomechanics and Medical Engineering Applied Mechanics Laboratory Department of Engineering MechanicsTsinghua University Institute of Nuclear and New Energy Technology Tsinghua University Shanghai Aerospace Control Technology Institute Shanghai Key Laboratory of Aerospace Intelligent Control Technology College of Automation Engineering Nanjing University of Aeronautics and Astronautics

Natural swarms arranged from cells to herds are usually decentralized but display intriguing collective intelligence in coordinating individuals across large scales to efficiently achieve their common goals. Learning from nature may provide new strategies for controlling collective dynamics of synthetic swarms to accomplish specific functions. Here, we present a bioinspired computational framework that steers distributed active swarms to collectively capture and merge targets via reinforcement learning. We exploit collective milling structures of natural herds to cage the targets, and adopt a switching control policy inspired by sperms' chiral dynamics to optimize the trajectories of individuals, through which the active swarms can selforganize to enclose single or multiple distant targets in a dynamical, adaptive and scalable manner. There exists a critical swarm size, beyond which the excessive competition between agents would generate large mechanical forces, leading to capture instability but enabling the transition from short-distance to long-distance merging capture of multiple targets. This work provides physical insights into distributed active swarms and could offer a multilevel, decentralized strategy toward controlling swarm robotics in wide applications such as bio-medical devices, machine immunity, and target clearance.

关键词： swarm intelligence robotics multi-tasks artificial intelligence bionics

Polymer microbottle with flexible tunability for ultrasensitive ultrasound sensing

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(Physics,Mechanics & Astronomy) 2025年

作者： Liaosha Kuang Jialve Sun Shengnan Huangfu Tinglan Chen Zijing Cai Tian xu xuanyi zhang bo Ni Fangxing zhang School of Physics and Technology Nantong University Peking University Yangtze Delta Institute of Optoelectronics State Key Lab for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of PhysicsPeking University School of Electronic Information Engineering Shanghai DianJi University

Optical whispering-gallery-mode microcavities have attracted significant attention for their potential in ultrasensitive ultrasound sensing, despite always relying on expensive tunable lasers in applications. In this study, we integrated an electrothermal tuning function inside the microcavity, enabling fast scanning of modes by applying voltages, which helps provide real-time searching and tracking of the optimal mode. Our device demonstrated a quality factor exceeding 10～6with a broad tuning range over 33 GHz. This structure achieved high sensitivity in ultrasound detection, with a noise equivalent pressure（NEP） of 3.35 mPa/Hz1/2at 20 MHz. We further reported the advantages of the mode thermal broadening effect for ultrasound detection, with successfully obtaining high-contrast photoacoustic images. Our research introduces an innovative approach for cost-effective, high-stability ultrasound detection with microcavity, showing great value for application in photoacoustic imaging.

关键词：

Superhydrophobic and corrosion-resistant siloxane-modified MgAl-LDHs coatings on magnesium alloy prepared under mild conditions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 450-463页

作者： Wenxi zhang zhangzelong Zhuo Dan xu Liang Wu Zhihui Xie Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province College of Chemistry and Chemical EngineeringChina West Normal UniversityNanchong 637002China College of Materials Science and Engineering/National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

We have developed a superhydrophobic and corrosion-resistant LDH-W/PFDTMS composite coating on the surface of Mg *** composite comprised a tungstate-intercalated(LDH-W)underlayer that was grown at low temperature(relative to hydrothermal reaction conditions)under atmospheric pressure and an outer polysiloxane layer created from a solution containing perfluorodecyltrimethoxysilane(PFDTMS)using a simple immersion *** successful intercalation of tungstate into the LDH phase and the following formation of the polysiloxane layer were confirmed through X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectroscopy,and X-ray photoelectron spectroscopy(XPS).The corrosion resistance of the LDH-W film,both before and after the PFDTMS modification,was evaluated using electrochemical impedance spectroscopy(EIS),Tafel curves,and immersion *** results showed that Mg coated with LDH-W/PFDTMS exhibited significantly enhanced corrosion protection compared to the unmodified LDHW film,with no apparent signs of corrosion after exposure to 3.5wt%NaCl solution for 15 ***,the LDH-W/PFDTMS coating demonstrated superior superhydrophobicity and self-cleaning properties against water and several common beverages,as confirmed by static contact angle and water-repellency *** results offer valuable insights into preparing superhydrophobic and corrosion-resistant LDH-based composite coatings on Mg alloy surfaces under relatively mild reaction conditions.

关键词： Mg alloy corrosion coating layered double hydroxide

基于热电比可调模式的区域综合能源系统双层优化运行

在线全文

学校读者我要写书评

暂无评论

电网技术 2016年第10期40卷 2959-2966页

作者：施锦月许健曾博张建华新能源电力系统国家重点实验室(华北电力大学) 北京市昌平区102206 国网河北省电力公司检修分公司河北省石家庄市050070

目前基于能量枢纽(energy hub,EH)的区域综合能源系统的优化运行缺乏对EH内热电联产(combined heat and power,CHP)机组热电比可调的考虑,且在此类场景中参与需求侧响应的负荷种类单一。针对此状况,构建双层优化模型,建立EH机组内部能... 详细信息

目前基于能量枢纽(energy hub,EH)的区域综合能源系统的优化运行缺乏对EH内热电联产(combined heat and power,CHP)机组热电比可调的考虑,且在此类场景中参与需求侧响应的负荷种类单一。针对此状况,构建双层优化模型,建立EH机组内部能效特性与外部能源分配的联系,实现内部机组高效运行和外部能源经济分配。模型通过卡罗需-库恩-塔克条件(Karush-Kuhn-Tucker Conditions,KKT)将双层优化转换为单层优化,并用确定性优化软件求解。算例结果表明,EH双层优化运行模型可减少用能成本,提高用能效率。通过调节CHP热电比,同时利用广义弹性负荷参与响应,可以减小CHP热电比与区域内热电负荷比之间差距,从而提高CHP供能比例,实现区域综合能源系统高效经济运行。

关键词： CHP热电比可调模式广义弹性负荷双层优化能量枢纽综合需求侧响应