加速溶剂萃取-气相色谱质谱法测定电子电气产品塑料部件中的多氯化萘

建立了测定电子电气产品塑料部件中的7种多氯化萘(PCNs)化合物的GC/MS法。粉碎后的样品经加速溶剂萃取法(ASE)萃取,并经硅胶小柱净化后,GC/MS法测定。7种多氯化萘的线性范围为：0.01～1.0μg/mL(相关系数R2＞0.999),加标回收率为64.0％～99.0％,相对标准偏差RSD为2.2％～9.9％。     

桂林会仙岩溶湿地入侵植物水葫芦营养成分及微量元素分析

测定了桂林会仙岩溶湿地入侵植物水葫芦茎叶和根中常规营养成分和微量元素的含量。结果表明,水葫芦茎叶和根部含有的TOC、TN、TP、TK、粗蛋白、粗灰分、木质素、纤维素、半纤维素、干物质含量、Fe、Cu、Ni、Pb、Cr、As、Hg和Cd元素含量,均表现为根部高于茎叶部;而粗脂肪、碳水化合物、干物质含量所占比例、Ca、Mg、Na、Mn和Zn元素含量则表现为茎叶部高于根部。干物质中含量较高的是碳水化合物、纤维素和粗灰分,水葫芦可适合作为动物饲料原料。尽管会仙岩溶湿地入侵植物水葫芦有害重金属含量未超标,但实践中必须考虑水葫芦作为饲料合理的平均日食用量,以保证饲料品质和安全。     

傅里叶变换近红外光谱法快速检测人血清生化成分

应用傅里叶变换近红外光谱透射技术结合偏最小二乘法(PLS)建立了人血清中7种生化成分的定标模型,利用内部交叉验证和自动优化功能对定标模型进行了优化,确定了最优建模参数。模型对人血清中总胆固醇、甘油三酯、总蛋白、白蛋白、载脂蛋白B、低密度脂蛋白胆固醇、葡萄糖定标样品集的预测值与化学值的相关系数r分别为0.9011、0.9593、0.9249、0.761、0.8831、0.5191、0 9148,预测校正标准误差RMSECV分别为15mg/dL,21.6mg/dL,2 66g/L,3 96g/L,0.091g/L,16.2mg/dL,0.49mmol/L。     

超高效液相色谱-串联质谱双内标法同时测定复方杏香兔耳风胶囊中的10种有效成分

建立了同时测定复方杏香兔耳风胶囊中原儿茶酸、原儿茶醛、绿原酸、野黄芩苷、异绿原酸C、黄芩苷、木犀草素、芹菜素、白术内酯Ⅲ和白术内酯I等10种有效成分含量的超高效液相色谱-串联质谱（UPLC-MS/MS）双内标分析方法。以咖啡酸和淫羊藿苷为内标（IS）,在ZORBAX RRHD Eclipse Plus C₁₈色谱柱上,以甲醇和含0.3%甲酸的水为流动相进行梯度洗脱分离,流速为0.3 mL/min。在电喷雾电离（ESI）正、负离子切换模式下,采用多重反应监测模式进行检测。结果表明,原儿茶酸、原儿茶醛、绿原酸、野黄芩苷、异绿原酸C、黄芩苷、木犀草素、芹菜素、白术内酯Ⅲ、白术内酯I的线性范围分别为0.00300~24.0 mg/L、0.0170~2.00 mg/L、0.0150~30.0 mg/L、0.00400~30.0 mg/L、0.0105~24.0 mg/L、0.00300~30.0 mg/L、0.00300~5.00 mg/L、0.00600~5.00 mg/L、0.00150~4.00 mg/L、0.000600~0.900 mg/L;检出限分别为1.0、11、5.0、1.5、3.5、1.0、1.0、2.0、0.50、0.20 μg/L。10种成分的加样回收率为92.5%~106%,相对标准偏差均不大于3.2%。该方法快速简便、灵敏度高、重复性好,已成功用于实际样品的分析。     

A FLEXIBLE POLYMER FIBRE INFRASTRUCTURE FOR AN EVOLUTIONARY CUSTOMER PREMISES NETWORK

The developments in compressed digital video technology are paving the way for video-based services. Provision of such services requires a broadband communications network, which should extend into the customers' premises up to the terminals. This indicates a growing need for a customer premises network. This paper presents an infrastructure for an evolutionary and future-proof customer premises network. Such an infrastructure allows for early deployment and gradual upgrades associated with service demand. A key element in the concept is the use of the graded index polymer optical fibre (GIPOF) which combines an intrinsically high bandwidth with easy and therefore low-cost handling. There are two opposite approaches for the choice of network topology. In one approach, all applications are forced onto a single topology. In the other approach, the topology best suited for each application type is used. This paper considers the ‘best-suited topology’ approach and presents a network infrastructure that can support many topologies simultaneously as independent overlay networks. The proposed infrastructure consists of bundles of fibres, which can be interconnected and accessed by terminals in any required manner. © 1997 by John Wiley & Sons, Ltd.     

Oriented walk double covering and bidirectional double tracing

An oriented walk double covering of a graph G is a set of oriented closed walks, that, traversed successively, combined will have traced each edge of G once in each direction. A bidirectional double tracing of a graph G is an oriented walk double covering that consists of a single closed walk. A retracting in a closed walk is the immediate succession of an edge by its inverse. Every graph with minimum degree 2 has a retracting free oriented walk double covering and every connected graph has a bidirectional double tracing. The minimum number of closed walks in a retracting free oriented walk double covering of G is denoted by c(G). The minimum number of retractings in a bidirectional double tracing of G is denoted by r(G). We shall prove that for all connected noncycle graphs G with minimum degree at least 2, r(G) = c(G) − 1. The problem of characterizing those graphs G for which r(G) = 0 was raised by Ore. Thomassen solved this problem by relating it to the existence of certain spanning trees. We generalize this result, and relate the parameters r(G), c(G) to spanning trees of G. This relation yields a polynomial time algorithm to determine the parameters c(G) and r(G). © 1998 John Wiley & Sons, Inc. J. Graph Theory 29: 89–102, 1998     

嵌入式PC机基于SOCKET通信在DOS下的实现

嵌入式PC安装一般是嵌入到其他设备或系统中,所以体积、功耗、抗震性等方面的特殊要求使其硬件环境与标准PC有所区别:其内存较小、无硬盘、甚至无显示功能或由远端的控制终端进行显示,因此视窗操作系统的强大功能发挥不出来,则DOS以其内核小、操作简单、实时性强就在嵌入式PC领域中占有重要地位。然而,DOS操作系统缺乏类似Win-sock的API,所以在该系统下设计基于TCP/IP协议的应用程序时难度较大,结合实例阐述基于DOS下的嵌入式系统中实现SOCKET通信的一种具体方法和过程。     

基于ARM核嵌入式微处理器的以太网应用

介绍了基于ARM920T核的32位高性能嵌入式处理器(S3C2410X)硬件平台中以太网控制器实现技术,针对嵌入式系统对实时性、可靠性的要求,首先分析了ARM系列处理器的体系结构,介绍这种处理器的优缺点以及面向嵌入式系统开发的优势。然后详细介绍了系统设计原则以及以太网接口模块的硬件实现方法。通过实践和比较,验证了设计方法的可行性与稳定性。     

嵌入式Linux下ARM处理器与DSP的数据通信

本文通过一个开发实例详细说明如何通过DSP的HPI接口与运行Linux操作系统的ARM架构处理器进行数据通信。给出接口部分的实际电路和ARM—Linux下驱动程序的开发过程。     

两个方差分量的不变二次估计的可容许性

本文对Ｙ￣Ｎ（Ｘβ，θ１Ｖ１＋θ２Ｖ２），Ｖ１，Ｖ２〉０给出了方差分量的线性函数的不变二次无偏估计、不变二次非负估计及不变二次估计不可容许的充要条件，并据此给出了具体判别上述估计的可容许性的方法。