水下无线光通信自组织网性能分析

针对无线光通信工作频率高、通信频带宽、数据传输能力强、传输距离远的特点,提出建立水下无线光通信自组织网。为解决水下无线光通信点对多点通信的问题,提出了一种组合折反射镜,为建立移动自组织网（MobileAdhocNetwork,MANET）提供条件。研究利用OPNET对按需距离向量协议（AODV）进行仿真,通过设置移动节点参数模拟水下无线光通信自组织网,分析了不同网络规模、不同节点速度、不同发包率对网络的吞吐量、时延、误比特率等性能的影响。仿真结果表明,AODV在节点速度5m／s--10m／s以下,网络规模10个节点左右,发包率小于20packets／s时对网络拓扑变化的适应性较好。     

Oxidative ring-opening of isatins for the synthesis of 2-aminobenzamides and 2-aminobenzoates

An efficient and practical isatin-based oxidative domino protocol has been developed for the facile synthesis of 2-aminobenzamides and 2-aminobenzoates. The robust nature of this reaction system is reflected by accessible starting materials, room temperature and high-yield gram-scale synthesis.     

Green synthesis of new thiouracilodepsipeptides in ionic liquid: One‐pot four‐component reaction of isocyanides

Thiouracil‐containing depsipeptides were produced via one‐pot four‐component condensation/Passerini tandem reaction of thiouracil, 2‐chloroacetic acid derivatives, ketones, and isocyanides in ionic liquid as green reaction media in high yields.     

Expected reliability of communication protocols

We consider the problem of sending a message from a sender $s$ to a receiver $r$ through an unreliable network by specifying in a protocol what each vertex is supposed to do if it receives the message from one of its neighbors. A protocol for routing a message in such a graph is finite if it never floods $r$ with an infinite number of copies of the message. The expected reliability of a given protocol is the probability that a message sent from $s$ reaches $r$ when the edges of the network fail independently with probability $1?p$.We discuss, for given networks, the properties of finite protocols with maximum expected reliability in the case when $p$ is close to 0 or 1, and we describe networks for which no one protocol is optimal for all values of $p$. In general, finding an optimal protocol for a given network and fixed probability is challenging and many open problems remain.     

Concise synthesis of dopexamine dihydrochloride via benzyl protecting protocol

Benzyl protecting protocol was first employed in two routes for the concise synthesis of dopexamine dihydrochloride.This protecting group could be cleanly removed under mild condition and no unacceptable ion was brought to the final product.The total yield of route I was 43.8% from phenylacetic acid,while it was 54.1% of route II from 2-(3,4-bis(benzyloxy)phenyl)acetic acid.The titration purity of the final product was more than 99.5%,while any single or total impurities met the known standard of the drug by HPLC analysis.The measured residual palladium met an acceptable limit(<1 ppm) as an API for injection.     

原子系综中光学腔增强的Duan-Lukin-Cirac-Zoller写过程激发实验

原子系综中的Duan-Lukin-Cirac-Zoller(DLCZ)过程是产生光与原子(量子界面)量子关联和纠缠的重要手段.当一束写光与原子发生作用时,将会产生斯托克斯(Stokes)光子的自发拉曼散射,并同时产生一个自旋波(spin-wave)存储在原子系综中,上述过程即为DLCZ量子记忆产生过程.这一过程被广泛地研究.本文将87Rb原子系综放入驻波腔,并使Stokes光子与光学腔共振,我们观察到有腔且锁定的情况下Stokes光子产生概率比无腔时增大了8.7倍.在此条件下研究了Stokes光子产生概率和写光功率的关系,Stokes光子产生概率随写光功率线性增大.     

Development,standardization and refinement of procedures for evaluating effects of endocrine active compounds on development and sexual differentiation of <Emphasis Type="Italic">Xenopus laevis</Emphasis>

Xenopus laevis has been introduced as a model to study effects of endocrine-active compounds (EAC) on development and sexual differentiation. However, variable and inconsistent data have raised questions about the reliability of the test methods applied. The current study was conducted in two laboratories to develop, refine, and standardize procedures and protocols. Larvae were exposed in flow-through systems to 17β-estradiol (E2), at concentrations from 0.2 to 6.0 μg E2 L⁻¹ in Experiment 1A, and 0.015 to 2.0 μg E2 L⁻¹ in Experiment 1B. In both studies survival (92%, 99%) and percentage of animals that completed metamorphosis (97%, 99%) indicated reproducible biological performance. Furthermore, minor variations in husbandry led to significant differences in snout-to-vent length, weight, and gonad size. In Experiment 1A, almost complete feminization occurred in all E2 treatment groups whereas a concentration response was observed in Experiment 1B resulting in an EC₅₀ of 0.12 μg E2 L⁻¹. The final verified protocol is suitable for determining effects of EAC on development and sexual differentiation in X. laevis.     

Experimental Investigation on Transmission Control Protocol Throughput Behavior in Optical Fiber Access Networks

ABSTRACT

This article describes an experimental investigation on the behavior of transmission control protocol in throughput measurements to be used in the verification of the service-level agreement between the Internet service provider and user in terms of line capacity for ultra-broadband access networks typical of fiber-to-the-x architectures. It is experimentally shown different conditions in high bandwidth-delay product links where the estimation of the line capacity based on a single transmission control protocol session results are unreliable. Simple equations reported in this work, and experimentally verified, point out the conditions in terms of packet loss, time delay, and line capacity, that allow consideration of the reliability of the measurement carried out with a single transmission control protocol session test by adopting a suitable measurement time duration.     

基于改进蚁群算法的LEACH协议研究

针对LEACH协议在数据传输阶段,簇首与汇聚节点之间采用单跳模式传输数据使得能量消耗快并且不均衡的问题,提出一种基于改进蚁群算法的新型路由协议。该协议利用了能耗因子对蚁群转移概率以及信息素更新进行改进,充分考虑了节点的剩余能量和节点间距离,通过信息素的建立和更新,寻找簇首节点和基站之间的最优传输路径,进行多跳传输模式,从而均衡簇首节点能量消耗。仿真实验结果表明,改进后的ACO-BEC协议较之于LEACH协议,能够有效降低了整个网络能量消耗,延长了网络寿命。     

IIC总线和LVDS在高速数据传输接口电路中的应用研究

当前在高速数据系统中,LVDS接口已被广泛应用,为实现同系列设备之间的智能识别、自动握手以及LVDS高速数据链路通信质量的检测,利用FPGA的IO电路结构,设计一种模拟IIC总线协议电路,该IIC总线高效地实现设备之间的信息双向传递;同时利用FPGA内部丰富寄存器资源设计PRBS码型电路来检测LVDS接口芯片电路误码率。实际测试表明该多通道LVDS传输方式在2米长电缆连接能够实现数据的稳定、低误码率传输,并且在时钟频率为100MHz时,数据传输速率高达4.68Gb/s。