Fibre optic installation techniques for pile instrumentation

An innovative technique based on optical fibre sensing that allows continuous strain measurement has recently been introduced in structural health monitoring. Known as Brillouin Optical Time-Domain Reflectometry (BOTDR), this distributed optical fibre sensing technique allows measurement of strain along the full length (up to 10km) of a suitably installed optical fibre. Examples of recent implementations of BOTDR fibre optic sensing in piles are described in this paper. Two examples of distributed optical fibre sensing in piles are demonstrated using different installation techniques. In a load bearing pile, optical cables were attached along the reinforcing bars by equally spaced spot gluing to measure the axial response of pile to ground excavation induced heave and construction loading. Measurement of flexural behaviour of piles is demonstrated in the instrumentation of a secant piled wall where optical fibres were embedded in the concrete by simple endpoint clamping. Both methods have been verified via laboratory works. © 2009 IOS Press.

Molecular evidence for diphyly of the Asian catfish family Amblycipitidae (Teleostei: Siluriformes) and exclusion of the South American Aspredinidae from Sisoroidea

Amblycipitidae Day, 1873 is an Asian family of catfishes (Siluriformes) usually considered to contain 28 species placed in three genera: Amblyceps (14 spp.), Liobagrus (12 spp.) and Xiurenbagrus (2 spp.). Morphology-based systematics has supported the monophyly of this family, with some authors placing Amblycipitidae within a larger group including Akysidae, Sisoridae and Aspredinidae, termed the Sisoroidea. Here we investigate the phylogenetic relationships among four species of Amblyceps, six species of Liobagrus and the two species of Xiurenbagrus with respect to other sisoroid taxa as well as other catfish groups using 6100 aligned base pairs of DNA sequence data from the rag1 and rag2 genes of the nuclear genome and from three regions (cyt b, COL ND4 plus tRNA-His and tRNA-Ser) of the mitochondrial genome. Parsimony and Bayesian analyses of the data indicate strong support for a diphyletic Amblycipitidae in which the genus Amblyceps is the sister group to the Sisoridae and a clade formed by genera Liobagrus and Xiurenbagrus is the sister group to Akysidae. These taxa together form a well supported monophyletic group that assembles all Asian sisoroid taxa, but excludes the South American Aspredinidae. Results for aspredinids are consistent with previous molecular studies that indicate these catfishes are not sisoroids, but the sister group to the South American doradoid catfishes (Auchenipteridae + Doradidae). The redefined sisoroid clade plus Bagridae, Horabagridae and (Ailia + Laides) make up a larger monophyletic group informally termed "Big Asia." Likelihood-based SH tests and Bayes Factor comparisons of the rag and the mitochondrial data partitions considered separately and combined reject both the hypothesis of amblycipitid monophyly and the hypothesis of aspredinid inclusion within Sisoroidea. This result for amblycipitids conflicts with a number of well documented morphological synapomorphies that we briefly review. Possible nomenclatural changes for amblycipitid taxa are noted.

A new species of Allocreadium (Trematoda : Allocreadiidae) from freshwater fishes in the Danjiangkou Reservoir in China

A new species of Allocreadium, Allocreadium danjiangensis n. sp., is described from the intestine of several species of freshwater fish, including Abbottina rivularis (Basilewsky, 1855), Sarcocheilichthys nigripinnis nigripinns (Gunther, 1873), Gnathopogon argentatus (Sauvage et Dabry 1874), Opsariichthys uncirostris bidens (Gunther, 1873), and Erythroculter mongolicus mongolicus (Basilewsky, 1855) (Cyprinidae) from the Danjiangkou Reservoir in central China. The main morphological characters of the new species are as follows: vitelline follicles numerous, extending from the level of acetabulum to posterior extremity, distributed over both sides around the ceca; cirrus sac relatively large, developed, lying obliquely anterior to the acetabulum, extending from the level of the intestinal bifurcation to the central level of acetabulum, and overlapping left or right cecal; and ovary much smaller than testes, generally close to or even overlapping the anterior border of anterior testis. Observation by scanning electron microscopy shows only 2 kinds of tegumental formations, i.e., papillae and tubercles, instead of 3 types of tegumental formations, i.e., papillae, bosses, and minute sensor receptors observed on other species of the Allocreadiidae. The tegumental striations of the present species vary on the different parts of the body. In addition, a new structure, identified as the "groove" with a tonguelike tubercle, was observed on the inner wall of acetabulum.

Purification and characterization of hydrosoluble components from the sap of Chinese lacquer tree Rhus vernicifera

Continuous gradient elution chromatography (CGEC) was employed to purify and separate enzymes and polysaccharides from the sap of Rhus vernicifera Chinese lacquer tree. There are three different molecules with laccase enzyme activity. Two are enzymes of each other (L1, and L2), whereas the third (RL) is an entirely separate entity. Two polysaccharides (GP1 and GP2) were also found. The Rhus laccase (RL), and isoenzymes L1 and L2, have peak molecular masses of 109,100, 120,000, 103,000 respectively; each has four copper atoms per molecule, and the pI values were 8.2, 8.6, and 9.1, respectively. The structure of the laccases was studied by Fourier-transform infrared (FT-IR) and Matrix-assisted laser desorption/ionization time-of flight (MALDI-TOF) mass spectrometry. The typical amide I (1646 cm(-1)) and amide II (1545 cm(-1)) bands were observed. The results from MALDI-TOF were similar to those from CGEC, but the molecular mass from the MALDI-TOF was significantly different from that obtained from sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). (c) 2006 Elsevier B.V. All rights reserved.

基于3×3耦合器的迈克尔逊干涉仪相位特性分析

国家８６３计划（２００７ＡＡ０３Ｚ４１５）

基于LDA模型的文本分割

文本分割在信息提取、文摘自动生成、语言建模、首语消解等诸多领域都有极为重要的应用.基于LDA模型的文本分割以LDA为语料库及文本建模,利用MCMC中的Gibbs抽样进行推理,间接计算模型参数,获取词汇的概率分布,使隐藏于片段内的不同主题与文本表面的字词建立联系.实验以汉语的整句作为基本块,尝试多种相似性度量手段及边界估计策略,其最佳结果表明二者的恰当结合可以使片段边界的识别错误率远远低于其它同类算法.

多室流化床内固体颗粒的流动行为研究——褐煤有效利用项目的冷态实验

基于褐煤热分解时既除去煤中的氮、又可回收焦油这一特点,该文针对褐煤的水分、灰分含量高及热解时释放的挥发份多但燃烧热值低而导致褐煤总的热值低、热利用效率不高的问题,提出了一种有效利用褐煤的方案:利用多室流化床技术,褐煤首先于缺氧条件下在热分解室内热解,释放出挥发份、水分、从挥发份中冷凝出焦油;然后热解得到的高热值的褐煤焦炭通过多室流化床的室与室之间分隔板上的开孔流入燃烧室内燃烧.这样处理既克服了褐煤热值低的缺点,又利用了其挥发份多的特点,收集到焦油.该文的研究工作作为该方案的冷态实验部分,在小型多室流化床冷态实验装置上,对固体颗粒(如由褐煤得到的焦炭等)通过多室流化床的室与室之间的分隔板上之开孔流通的行为及规律进行了研究. 

基于3×3耦合器的迈克耳孙干涉仪相位特性分析

研究了基于3×3耦合器的非平衡迈克耳孙干涉仪的相位特性。由光纤耦合器的散射矩阵理论,推导出了当3×3耦合器分光比不均匀时,干涉仪三路输出信号相位差的表达式。根据实际使用的3×3耦合器各通道的插入损耗,经计算与修正得到其散射矩阵,并求出干涉仪三路输出信号的相位差分别为120.21°、120.77°和119.02°,与理想值120°的偏差在1°以内。实验测得的干涉仪三路输出信号的相位差随时间随机变化,经分析是由光偏振态随机变化引起的。相位差与理想值120°的偏离均在1°以内,符合理论分析得到的结论。

Isoscaling parameter a as a possible probe of medium effect of nucleon-nucleon cross section

The medium effect of nucleon-nucleon cross section sigma(med)(NN) (alpha(m)) on the isoscaling parameter a is investigated for two central nuclear reactions Ca-40+Ca-40, Ca-60+Ca-60. within isospin-dependent quantum molecular dynamics at beam energies from 40 to 50 MeV/nucleon. It is found that there is the very obvious medium effects of nucleon-nucleon cross section sigma(med)(NN)(alpha(m)) on the isoscaling parameters a. In this case the isoscaling parameter a is a possible probe of the medium effect of nucleon-nucleon cross section sigma(med)(NN)(alpha(m)) in the heavy ion collisions. The mechanism of the above-mentioned properties is studied and discussed.