Analysis of estrogens in environmental waters using polymer monolith in-polyether ether ketone tube solid-phase microextraction combined with high-performance liquid chromatography

A simple, rapid and sensitive on-line method for simultaneous determination of four endocrine disruptors (17 beta-estradiol, estriol, bisphenol A and 17 alpha-ethinylestradiol) in environmental waters was developed by coupling in-tube solid-phase microextraction (SPME) to high-performance liquid chromatography (HPLC) with fluorescence detection (FLD). A poly(acrylamide-vinylpyridine-NAP-methylene bisacrylamide) monolith, synthesized inside a polyether ether ketone (PEEK) tube, was selected as the extraction medium. To achieve optimum extraction performance, several parameters were investigated, including extraction flow-rate, extraction time, and pH value, inorganic salt and organic solvent content of the sample matrix. By simply filtered with nylon membrane filter and adjusting the pH of samples to 6.0 with phosphoric acid, the sample solution then could be directly injected into the device for extraction. Low detection limits (S/N = 3) and quantification limits (S/N = 10) of the proposed method were achieved in the range of 0.006-0.10 ng/mL and 0.02-0.35 ng/mL from spiked lake waters, respectively. The calibration curves of four endocrine disruptors showed good linearity ranging from quantification limits to 50 ng/mL with a linear coefficient R-2 value above 0.9913. Good method reproducibility was also found by intra- and inter-day precisions, yielding the RSDs less than 12 and 9.8%, respectively. Finally, the proposed method was successfully applied to the determination of these compounds in several environmental waters. (c) 2006 Elsevier B.V. All rights reserved.

Molecular cloning and stress-induced expression of paralichthys olivaceus heme-regulated initiation factor 2 alpha kinase

The heme-regulated initiation factor 2 alpha kinase (HRI) is acknowledged to play an important role in translational shutoff in reticulocytes in response to various cellular stresses. In this study, we report its homologous cDNA cloning and characterization from cultured flounder embryonic cells (FEC) after treatment with UV-inactivated grass carp haemorrhagic virus (GCHV). The full-length cDNA of Paralichthys olivaceus HRI homologue (PoHRI) has 2391 bp and encodes a protein of 651 amino acids. The putative PoHRI protein exhibits high identity with all members of eIF2 alpha kinase family. It contains 12 catalytic subdomains located within the C-terminus of all Ser/Thr protein kinases, a unique kinase insertion of 136 amino acids between subdomains IV and V, and a relatively conserved N-terminal domain (NTD). Upon heat shock, virus infection or Poly PC treatment, PoHRI mRNA and protein are significantly upregulated in FEC cells but show different expression patterns in response to different stresses. In healthy flounders, PoHRI displays a wide tissue distribution at both the mRNA and protein levels. These results indicate that PoHRI is a ubiquitous eIF2a kinase and might play an important role in translational control over nonheme producing FEC cells under different stresses. (c) 2006 Elsevier Ltd. All rights reserved.

Inductive expression and characterization analysis of Paralichthys olivaceus pigment epithelium-derived factor in a virally infected cell line

Pigment epithelium-derived factor (PEDF) is acknowledged to be a non-inhibitory member of the serine protease inhibitor (serpin) superfamily, with antiangiogenesis, and neuroprotective and immumoregulatory function, mainly in the tissues of nervous system. Here, A PEDF gene homolog, Paralichthys olivaceus PEDF (PoPEDF), was isolated from flounder embryonic cells (FEC) treated with UV-inactivated Grass carp hemorrhage virus (GCHV) and subsequently identified as a differentially expressed gene. The full length of PoPEDF cDNA is 1803 bp with an open reading frame of 1212 bp encoding a 403-amino-acid protein. This deduced protein contains an N-terminal signal peptide, a glycosylation site, a consensus serpin motif, and a 34-mer and a 44-mer fragment, all of which are very conserved in the PEDF family. PoPEDF gene exhibits a conserved exon-intron arrangement with 8 exons and 7 introns. This conserved evolutionary relationship was further confirmed by a phylogenetic analysis, where fish PEDFs and mammalian members formed a well-supported clade. Constitutive expression of PoPEDF was widely detected in many tissues. In response to UV-inactivated GCHV or poly(I:C), PEDF mRNA was upregulated in FEC cells with time. This is the first report on the transcriptional induction of PEDF in virally infected cells. (C) 2005 Elsevier Inc. All rights reserved.

Electron transport properties of In0.53Ga0.47As/In0.52Al0.48As quantum wells with two occupied subbands

Magnetotransport properties of two-dimensional electron gas have been investigated for three In0.53Ga0.47As/In0.52Al0.48As quantum well samples having two occupied subbands with different well widths. When the intersubband scattering is considered, we have obtained the subband density, transport scattering time, quantum scattering time and intersubband scattering time, respectively, by analyzing the result of fast Fourier transform of the first derivative of Shubnikov-de Haas oscillations. It is found that the main scattering mechanism is due to small-angle scattering, such as ionized impurity scattering, for the first subband electrons.

Weak anti-localization in InAlAs/InGaAs/InAlAs high mobility two-dimensional electron gas systems

Magneto-transport measurements have been carried out on three heavily Si delta-doped In-0.52 Al-0.48 As/In-0.53 Ga-0.47 As/In-0.52 A(10.48) As single quantum well samples in which two subbands were occupied by electrons. The weak anti-localization (WAL) has been found in such high electron mobility systems. The strong Rashba spin-orbit (SO) coupling is due to the high structure inversion asymmetry (SIA) of the quantum wells. Since the WAL theory model is so complicated in fitting our experimental results, we obtained the Rashba SO coupling constant alpha and the zero-field spin splitting Delta(0) by an approximate approach. The results are consistent with that obtained by the Shubnikov-de Haas (SdH) oscillation analysis. The WAL effect in high electron mobility system suggests that finding a useful approach for deducing alpha and Delta(0) is important in designing future spintronics devices that utilize the Rashba SO coupling.

Observations on subband electron properties in In0.65Ga0.35As/In0.52Al0.48As MM-HEMT with Si delta-doped on the barriers

Magneto-transport measurements have been carried out on a Si delta-doped In0.65Ga0.35As/In0.52Al0.48As metamorphic high-electron-mobility transistor with InP substrate in a temperature range between 1.5 and 60 K under magnetic field up to 13 T. We studied the Shubnikov-de Haas (SdH) effect and the Hall effect for the In0.65Ga0.35As/In0.52Al0.48As single quantum well occupied by two subbands and obtained the electron concentration and energy levels respectively. We solve the Schrodinger-Kohn-Sham equation in conjunction with the Poisson equation self-consistently and obtain the configuration of conduction band, the distribution of carriers concentration, the energy level of every subband and the Fermi energy. The calculational results are well consistent with the results of experiments. Both experimental and calculational results indicate that almost all of the delta-doped electrons transfer into the quantum well in the temperature range between 1.5 and 60 K.

Indole Alkaloids from the Leaves of Anthocephalus chinensis

Anthocephalusine A (1) and 3 beta-isodihydrocadambine 4-oxide (2) were isolated from the leaves of Anthocephalus chinensis (Rubiaceac), together with five known compounds. The structures were established by spectroscopic methods including 2D-NMR analyses.

Picosecond ultra-wideband short pulse radiated by antenna arrays

This report presents the experiments to study the characteristics of the picosecond ultra-wideband pulses coherent radiation. The testing involves bow-tie horn antennas for both the transninting and receiving antenna. Sixteen channels of electrical pulses with 290 ps duration and jitter < 30 ps have been used. The antenna arrays with various frames of 4 x 1, 4 x 2, 4 x 3, 4 x 4 are employed to radiate the pulses. The receiving antenna measures the electrical field in different distance front the transmitting antennas arrant The results show that if the pulses are in coherent condition, the peak power pulse of output by antennas array with N elements are N-2 of that of the single element antenna. (c) 2007 Wiley Periodicals, Inc.

尺寸诱导的聚合物亚稳结晶

亚稳定性是凝聚态物质的一个重要特征。常温常压下，热力学上不稳定的、而实际上存在的相，都可称之为亚稳相。通常，影响物质亚稳态存在的外界因素有温度、压力、电场、磁场等等，而相态本身的大小也是决定它稳性的一个重要因素，这就是所谓的尺寸效应。随着纳米技术和微处理器技术的飞速发展，材料的应用尺寸日趋于小型化和微型化。研究聚合物相行为和相变中的尺寸效应，对于充分理解高分子凝聚态物理学的基本问题具有极度其重要的科学意义，它还为纳米科技中材料特殊的结构和性能提供新的认识途径和理论基础，这必将极度大地促进纳米材料的实用化进程。本文正是基于这样一种相变中的尺寸效应，选用了三种具有多晶型结构的结晶聚合物，聚偏氟乙烯（PVDF），聚反式1,4-丁二烯（TPBD）和尼龙1010（nylon 1010），对它们的晶体结构及其相转变过程和转变条件作了较详细的研究，着重探讨了各种晶型稳态和亚稳态的存在条件。在这三种聚合物当中，发现小尺寸晶体趋向于形成二维高有序的六方或拟六方堆积结构，成功地证明了晶体结构对尺寸的依赖性。在上述研究中，首次成功地为PVDF营造了不同程度的空间受限结晶环境，得到了尺寸小于100纳米受限结晶的亚稳态β晶；通过结合使用常温和低温的电子衍射术，并利用计算机模拟技术，提出了尺寸影响的TPBD相转变的具体实现过程；发现了培养尼龙1010单晶的另一理想溶剂二甲基甲酰胺（DMF），并首次用它培养出十分完善的单晶体；引入尺寸效应的观点来解释尼龙1010的Brill转变现象，定量地确定了基转变温度对尺寸的依赖关系，为解释这一古老但至仿仍存在极大争议的尼龙中特有的转变现象开辟了创造性的思维方式；首次用极度稀溶液喷雾法获得了尼龙1010的纳米和微米级微纤维晶，并解释了它的形成原因。

聚合物结晶过程及形态结构的研究

聚合物结晶过程是高分子科学中的一个重要研究方向。本论文在系统研究几种聚合物结晶过程及形态结构的基础上，通过寻求合适的解析聚合物结晶动力学参数的方法，为聚合物结晶动力学的表征和加工工艺设计提供科学依据。采用偏光显微镜（POM）研究了尼龙1212（Nylon 1212）、聚丁二酸丁二醇酷（PBS）及其与己二酸的共聚物（PBS／A）的等温结晶过程。发现碰撞前后球晶的生长速率不变，而在结晶后期球晶生长速率逐渐减慢。PBS／A环带球晶生长过程中球晶半径和结晶时间并非完全的线性关系，而是在直线两侧周期性地摆动。首次非常清晰地观察到PBS结晶后期弱区中新球晶的成核和生长。采用非等温方法在较低的降温速率下获得的聚合物球晶生长速率与等温方法得到的结果有可比性。在计算Nyton1212平衡热力学参数的基础上，采用L-H二次成核理论对N贝on1212的结晶行为进行分析，发现区域I→II和II-III转变分别发生在179Oc和159OC。随着结晶温度的降低，Nylon1212的结晶形态分别为轴状结构晶体、环带球晶和非环带球晶。广角X射线衍射（WAXD）研究表明，PBS和PBS／A具有相同的晶体结构。与PBS相比，PBS／A的结晶度和结晶速率下降。PBS和PBS／A均出现了区域n一Hl的转变，分别发生在％。C和75OC。随着结晶温度的降低，PBS和PBS／A的结晶形态分别为轴状结构晶体、非环带球晶和环带球晶。与PBS相比，PBS／A形成的环带球晶更规整。采用示差扫描量热法（DSC）研究了Nylon 1212、PBS、PBS／A和间规1，2聚丁二烯（st-1，2PB）的本体结晶动力学。发现采用序列一并列Avrami方程能较好地描述Nylon1212的等温结晶全过程。采用不同方法对st-1，2PB的非等温结晶动力学进行研究，发现由Jeziony方法和ozawa方法分析很难得到可靠的动力学参数，而根据莫志深等提出的新方法可较好地进行描述。采用Vyazovkin方法计算了Nylon 1212、st-1，2PB、PBS和PBS／A的非等温结晶活化能，均发现结晶活化能随相对结晶度的升高而升高。初步研究了结晶条件和扫描速率对Nylon 1212、st-1，2PB、PBs和PBs／A熔融行为的影响，并根据Hoffinan-Weeks方法求得了几种聚合物的平衡熔融温度。

STUDY OF THE LONG-TERM STABILITY OF THE EFFECTIVE CONCENTRATION OF IONIZED SPACE CHARGES (N-EFF) OF NEUTRON-IRRADIATED SILICON DETECTORS FABRICATED BY VARIOUS THERMAL-OXIDATION PROCESSES

Experimental study of the reverse annealing of the effective concentration of ionized space charges (N-eff, also called effective doping or impurity concentration) of neutron irradiated high resistivity silicon detectors fabricated on wafers with various thermal oxides has been conducted at room temperature (RT) and elevated temperature (ET). Various thermal oxidations with temperatures ranging from 975 degrees C to 1200 degrees C with and without trichlorethane (TCA), which result in different concentrations of oxygen and carbon impurities, have been used. It has been found that, the RT annealing of the N-eff is hindered initially (t < 42 days after the radiation) for detectors made on the oxides with high carbon concentrations, and there was no carbon effect on the long term (t > 42 days after the radiation) N-eff reverse annealing. No apparent effect of oxygen on the stability of N-eff has been observed at RT. At elevated temperature (80 degrees C), no significant difference in annealing behavior has been found for detectors fabricated on silicon wafers with various thermal oxides. It is apparent that for the initial stages (first and/or second) of N-eff reverse annealing, there may tie no dependence on the oxygen and carbon concentrations in the ranges studied.

In situ annealing treatment and In-doping of GaN epilayers grown by MOVPE

The effects of in situ annealing treatment in the initial growth stage and In-doping during growth of the GaN on the material properties were investigated. GaN was grown by LP-MOVPE. In situ annealing reduced the full-width at half-maximum (FWHM) of X-ray rocking curves and reduced etch pit density of GaN films. It improved the optical properties of the epilayer. Undoped and In-doped GaN films of initial growth stage were investigated. It was found that morphology and optical properties were improved in In-doped samples. (C) 2000 Elsevier Science B.V. All rights reserved.

从面向对象的遗留系统到面向服务架构的迁移方法

Migrating legacy system with web service is an effective and economic way of reusing legacy software in a SOA environment.In this paper,we present an approach for migrating a three-tie object-oriented legacy system to SOA environment.The key issue of the approach is about services identification from large numbers of classes.And we propose a bottom-up method to model the system with UML and identify services from UML then.This approach can be a reference to an auto-migrating process.