Effects of time delay and coupling strength on synchronization transitions in excitable homogeneous random network

In this paper we numerically investigate the effects of time delay and coupling strength on synchronization transitions in excitable homogeneous random network. Different roles of time delay and coupling strength have been discovered by synchronization parameter and space–time plots. Specifically, we have found three distinct parameter regions, i.e., asynchronous region (domain I for small time delay), transition region (domain II for moderate time delay) and synchronous region (domain III for large time delay) as time delay is increased. The phenomenon of multi-stability is observed in the transition region. While coupling strength can enhance synchronization in the transition region and can reduce synchronization time in the synchronous region. All these results are independence on the system size.     

基于信令与DPI的4G用户回家后上网方式的研究

提出了一种基于4G信令、移动及固网DPI关联的分析手段,对4G用户在家上网的方式(4G、Wi-Fi)做深入分析,并结合4G网络流量资源情况,指引建设资金更加精准投向业务需求区域.     

基于Android的动态心率检测系统的设计与实现

以便携、方便、低成本化为设计目标,将Android系统手机与蓝牙芯片、信号采集芯片进行功能设计和整合,使其具有捕获、保存心脏相关参数指标,并依据临床诊断标准对捕获参数进行分析,以及生成建议性检测报告的功能.在实际使用中,对监测、治疗和预防心血管类型疾病都将产生积极的作用.     

Experimental research on the localized electrochemical micro-machining

Due to several advantages and wider range of applications, micro-ECM is considered to be one of the most effective advanced future micromachining techniques. An experimental set-up for micro-ECM is constructed, which consists of various components and sub-systems, e.g. mechanical machining unit, nanosecond pulse power supply, circulation system of electrolyte, movement control component and process monitoring component. In addition, this system has the functions of fabricating micro tool electrode and machining status detection. Using the self-developed experimental system, the micro tool-electrode and the micro holes are sequentially machined. Upon the application of ultrashort voltage pulses, micro hole with 20μm diameter is obtained. Experimental results show the potential capability of electrochemical micromachining for better machining accuracy and smaller machining size. Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 8, pp. 998–1003. The text was submitted by the authors in English.     

Boosting the Proton-coupled Electron Transfer via Fe−P Atomic Pair for Enhanced Electrochemical CO2 Reduction

Single-atom catalysts exhibit superior CO₂-to-CO catalytic activity, but poor kinetics of proton-coupled electron transfer (PCET) steps still limit the overall performance toward the industrial scale. Here, we constructed a Fe−P atom paired catalyst onto nitrogen doped graphitic layer (Fe₁/PNG) to accelerate PCET step. Fe₁/PNG delivers an industrial CO current of 1 A with FE_CO over 90 % at 2.5 V in a membrane-electrode assembly, overperforming the CO current of Fe₁/NG by more than 300 %. We also decrypted the synergistic effects of the P atom in the Fe−P atom pair using operando techniques and density functional theory, revealing that the P atom provides additional adsorption sites for accelerating water dissociation, boosting the hydrogenation of CO₂, and enhancing the activity of CO₂ reduction. This atom-pair catalytic strategy can modulate multiple reactants and intermediates to break through the inherent limitations of single-atom catalysts.     

Distributed mirror descent method for saddle point problems over directed graphs

In this article, we consider a mini‐max multi‐agent optimization problem where multiple agents cooperatively optimize a sum of local convex–concave functions, each of which is available to one specific agent in a network. To solve the problem, we propose a distributed optimization method by extending classical mirror descent algorithms to the distributed setting. We obtain the convergence of the algorithm under wild conditions that the agent communication follows a directed graph and the related weighted matrices are row stochastic. In particular, when the weighted matrices are restricted to be doubly stochastic, we provide the explicit convergence rate of the algorithm by choosing the stepsize in a suitable way. The proposed algorithm can be viewed as a generalization of the subgradient projection methods since it utilizes a customized Bregman divergence instead of the usual Euclidean squared distance. Finally, some simulation results on a matrix game are presented to illustrate the performance of the algorithm. © 2016 Wiley Periodicals, Inc. Complexity 21: 178–190, 2016     

Compensated compactness applied to perturbed fourth and sixth order P. D. E.

I.Introducti0nlnthearticle,wemainlydiscussthefollowingequations:wherej(.)isasmoothnonlinearmapfromRtoR,l'l2andlI'if2.denotethenormofH'(R)andthenormofL'"(R),respectively,C0isaconstant.Asdandsgotozero,theconvergenceandregularityforthesolutionsofEq.(l.l)andE…     

一种改性的TGS:Be2+热释电单晶体

本文报道了在TGS中掺入适量的金属铍离子的新晶体生长特性,晶体形貌分析,同时测定了新晶体的热释电系数(P)、介电常数(ε)、居里温度(Tc).实验表明,在TGS中掺入金属铍离子生成的TGAS:Be2+晶体的优值比明显提高.     

水热法制备二氧化锡/钨酸铋复合光催化材料及其催化活性研究

本文用水热法制备了正交晶系的纳米球状结构的二氧化锡和正交晶系的由片状聚集成球状结构的钨酸铋,并且对二者进行了复合,制备出了二氧化锡/钨酸铋复合光催化材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、比表面积测试仪(BET)、紫外可见分光光度计等技术对复合样品的结构、形貌、比表面积、孔容孔径和光学性质进行了表征。用碘钨灯模拟太阳光,分别以二氧化锡、钨酸铋和二氧化锡/钨酸铋复合材料为催化剂降解罗丹明B(RhB),研究所制备的二氧化锡/钨酸铋复合材料的光催化活性。光催化90 min时二氧化锡、钨酸铋和二氧化锡/钨酸铋对罗丹明B的降解率分别是9%、22%和30%。实验结果表明,在可见光下,二氧化锡/钨酸铋复合材料的光催化活性要高于单一的二氧化锡和钨酸铋。     

二乙醇胺改性聚乳酸的直接熔融聚合法合成及其表征

以乳酸(LA)、二乙醇胺(DEA)为原料,采用熔融聚合法直接合成了二乙醇胺改性聚乳酸,并用特性粘数、FT-IR、1H NMR、GPC、DSC、XRD等手段进行表征,探讨了催化剂种类和用量、熔融聚合反应时间、反应温度以及不同投料比、不同构型乳酸对聚合物合成的影响.在单体投料摩尔比n(DEA):n(L-LA)=1:200、160℃、70Pa、催化剂SnO用量0.7(wt)%、熔融聚合8h条件下,聚合物重均相对分子质量(Mw)可达8100.随着投料比中DEA的增加,产物特性粘数逐步降低,Mw逐渐减小,玻璃化温度(Tg)有降低的趋势.以L-LA聚合得到的聚合物的Mw、分散度(Mw/Mn)和结晶度均比由D,L-LA得到的产物的更高.因此,笔者认为,由于D,L-A与L-LA存在反应速率差异,因而二者有不同的反应历程.新合成方法有利于降低二乙醇胺改性聚乳酸作为药物缓释载体等生物医学材料的合成成本.