Physical property measurement of therapeutic carbon ion beam in the shallow-seated tumor therapy terminal at HIRFL

For the first time the physical properties of therapeutic carbon-ion beam supplied by, the shallow-seated tumor therapy terminal at the Heavy Ion Research Facility in Lanzhou (HIRFL) are measured. For a 80.55MeV/u C-12 ion beam delivered to the therapy terminal, the homogeneity of irradiation fields is 73.48%, when the beam intensity varied in the range of 0.001-0.1nA (i.e. 1 X 10(6) - 1 X 10(8) particles per second). The stability of the beam intensity within a few minutes is estimated to be 80.87%. The depth-dose distribution of the beam at the isocenter of the therapy facility is measured, and the position of the high-dose Bragg peak is found to be located at the water-equivalent depth of 13.866mm. Based on the relationship between beam energy and Bragg peak position, the corresponding beam energy at the isocenter of the therapy terminal is evaluated to be 71.71MeV/u for the original 80.55MeV/u C-12 ion beam, which consisted basically with calculation. The readout of the previously-used air-free ionization chamber regarding absorbed dose is calibrated as well in this experiment. The results indicate that the performance of the therapy facility should be optimized further to meet the requirements of clinical trial.

CSR外靶实验终端中CsI(Tl)晶体的测试；Test of CsI(Tl) Crystal at External Target Experimental Terminal of Cooling Storage Ring

为测量重离子加速器冷却储存环(HIRFL-CSR)的外靶实验终端上不同能量的γ射线,一种用于探测γ射线的高能量分辨的探测装置正在中国科学院近代物理研究所建设,该探测器由中国科学院近代物理研究所自行生长的铊激活的碘化铯CsI(Tl)晶体组成。与日本Hamamatsu公司生产的S8664-1010型雪崩光二极管(APD)耦合,测试其光输出的非均匀性和能量分辨,从测试结果给出了所需CsI(Tl)晶体合格的标准。目前已完成该γ探测球计划的六分之一,所提供的晶体合格率达94%以上。

Capillary array electrophoresis with confocal fluorescence rotary scanner

A capillary array electrophoresis system with rotary corifocal fluorescence scanner was reported. High speed direct current rotary motor combined with a rotary encoder and the reflection mirror has been designed to direct exactly the excitation laser beam. to the array of capillaries, which are symmetrically distributed around the motor. The rotary encoder is introduced to accurately orient the position of each capillary and its output signal triggers the data acquiring system to record. the fluorescence signal corresponding to each capillary. Separations of several amino acids are demonstrated by eight-channel capillary array electrophoresis built by ourselves.

Highly enantioselective resolution of terminal epoxides with cross-linked polymeric salen-Co(III) complexes

Crosslinked polymeric salen-Co(III) complexes derived from a novel dialdehyde and a trialdehyde were synthesized and employed in the hydrolytic kinetic resolution (HKR) of terminal epoxides. Up to 99%, ee were obtained with only 0.16-0.02 mol%,, of catalyst (based on catalytic unit). (C) 2003 Elsevier Ltd. All rights reserved.

Soil microbial community analysis using terminal restriction fragment length polymorphisms

Terminal restriction fragment length polymorphism (T-RFLP) analysis is a polymerase chain reaction (PCR)-fingerprinting method that is commonly used for comparative microbial community analysis. The method can be used to analyze communities of bacteria, archaea, fungi, other phylogenetic groups or subgroups, as well as functional genes. The method is rapid, highly reproducible, and often yields a higher number of operational taxonomic units than other, commonly used PCR-fingerprinting methods. Sizing of terminal restriction fragments (T-RFs) can now be done using capillary sequencing technology allowing samples contained in 96- or 384-well plates to be sized in an overnight run. Many multivariate statistical approaches have been used to interpret and compare T-RFLP fingerprints derived from different communities. Detrended correspondence analysis and the additive main effects with multiplicative interaction model are particularly useful for revealing trends in T-RFLP data. Due to biases inherent in the method, linking the size of T-RFs derived from complex communities to existing sequence databases to infer their taxonomic position is not very robust. This approach has been used successfully, however, to identify and follow the dynamics of members within very simple or model communities. The T-RFLP approach has been used successfully to analyze the composition of microbial communities in soil, water, marine, and lacustrine sediments, biofilms, feces, in and on plant tissues, and in the digestive tracts of insects and mammals. The T-RFLP method is a user-friendly molecular approach to microbial community analysis that is adding significant information to studies of microbial populations in many environments.

容器苗质量评定指标的研究

In this paper,the assessing indices of container seedlings quality were synthesized in accordance with growth and physiological factors. The results showed that the seedling quality might be determined by the dormancy state of terminal bud,nutrient condition of plant,and the state of root system. The critical quality indices should include stem diameter at soil surface,dry weight of terminal bud,and soluble sugar content. Moreover,some indices such as root system vitality and dry weight of plant were also important.

Electrochemiluminescent microoptoprobe with mini-grid working electrode and self-contained sample container

A new electrochemiluminescence (ECL) microoptoprobe with simple structure. small sampling volume and high efficiency was developed. It was constructed by fixing the transparent gold mini-grid on the end surface of the optical fiber, and by surrounding the fiber with the counter- and reference electrodes to form a self-contained three-electrode system. The use of mini-grid electrode increased the surface area and collection efficiency. which resulted in higher ECL signal and better sensitivity. The counter electrode together with one end of the fiber formed a mini-vessel, which eliminated the need of additional container and allowed to perform ECL detection in a very small volume (about 10 mul). The microoptoprobe obtained was characterized with the Ru(bpy)(3)(2-)-tripropylamine system and was applied for the determination of oxalate and chlorpromazine (CPZ). Detection limits (S/N = 3) were 5 x 10(-7) and 1 x 10(-6) mol l(-1) for oxalate and CPZ. respectively. The linear range for oxalate and CPZ extended from 1 x 10(-6) to 1 x 10(-3) mol l(-1), and from 5 x 10(-6) to 5 x 10(-4) mol l(-1). respectively.

Voltammetric study of the sodium ion transfer across micro-water/1,2-dichloroethane interface facilitated by terminal-vinyl liquid crystal crown ether

Sodium ion transfer across micro-water/1,2-dichloroethane (DCE) interface facilitated by a novel ionophore, terminal-vinyl liquid crystal crown ether (LCCE) was studied by cyclic voltammetry. LCCEs have potential applications because of their physicochemical properties and the utilization of crown ethers as selective ionophoric units in other functionalized compounds are interesting. Host-guest-type behavior for such compounds in the liquid-crystalline state is studied. The experimental results suggest that the transfer of the sodium ion facilitated by LCCE was controlled by diffusion of LCCE from bulk solution of DCE to the interface. The diffusion coefficient of LCCE in DCE was calculated to be equal to (3.62 +/- 0.20) x 10(-6) cm(2)/s. Steady-state voltammograms are due to sodium ion transfer facilitated by the formation of 1: 1 metal (M)-LCCE complex at the interface and the mechanism tends to be transfer by interfacial complexation or dissociation (TIC or TID). The stability constant of the complex formed was determined to be log beta(o) = 5.5 in DCE phase. The influence of parameters such as concentration of sodium ion and concentration of LCCE on the sodium ion transfer was investigated.

Cys-92, Cys-95, and the C-terminal 12 residues of the Vibrio harveyi ferric uptake regulator (Fur) are functionally inessential

Ferric uptake regulator (Fur) is a global regulator involved in multiple aspects of bacterial life. The gene encoding the Vibrio harveyi Fur (Fur(vh)) was cloned from a pathogenic V. harveyi strain isolated from diseased fish. Furvh shares 77% overall sequence identity with the Escherichia coli Fur (Fur(Ec)) and could complement a mutant of Fur(Ec). Like Fur(Ec), Fur(Vh), possesses two cysteine residues at positions 92 and 95, yet unlike Fur(Ec), in which these cysteine residues constitute part of the metal ion coordination site and hence are vital to the repressor activity, C92 and C95 of Fur(Vh) proved to be functionally inessential. Further study identified a Vibrio Fur signature sequence, which is preserved in all the ten Vibrio Fur proteins that have been discovered to date but in none of the non-vibrio Fur proteins. Site-directed and random mutation analyses of the signature residues, the cysteine residues, and seven highly charged amino acid residues indicated that D9, H32, C137, and K138 of Fur(vh) are functionally important but D9, C137, and K138 can be replaced by more than one functional substitutes. Systematic deletion analysis demonstrated that the C-terminal 12 residues of Fur(Vh) are functionally inessential. These results (i) indicated that the activation mechanism, or certain aspects of which, of Fur(Vh) is possibly different from that of Fur(Ec); and (ii) suggested that it is not very likely that the C-terminal 12 residues play any significant role in the activation or stability of Fur(Vh); and (iii) provided insights into the potential function of the local structure involving C137 and K138.

Paleoenvironment evolution of the East Philippine Sea recorded in the new-type ferromanganese crust since the terminal Late Miocene

From systemic research of microstructure, geochemistry, uranium-series and Be-10 isotope dating on a new-type deepwater ferromanganese crust from the East Philippine Sea, the paleoenvironment evolution of the target area since the terminal Late Miocene was recovered. The vertical section changes of microstructure and chemical composition are consistent in the studied crust, which indicate three major accretion periods and corresponding paleoenvironment evolution of the crust. The bottom crust zone was formed in the terminal Late Miocene (5.6 Ma) with loose microstructure, high detritus content and high growth rate. Reductions of mineral element content, accretion rate and positive Ce-anomaly degree at 4.6 Ma indicate temporal warming, which went against the crust accretion and finally formed an accretion gap in the terminal Middle Pliocene (2.8-2.7 Ma). The more active Antarctic bottom seawaters in the Late Pliocene (2.7 Ma) facilitated the fast transfer to the top pure crust zone. Hereafter, with the further apart of volcanic source and the keeping increase of eolian material (1.0 Ma), although surrounding conditions were still favorable, mineral element content still shows an obvious reducing trend. It thereby offers new carrier and data for the unclear paleoceanographic research of the target area since the terminal Late Miocene.

档案自动录入及管理系统的研究

将用特定的表格形式填写的档案信息用扫描仪扫入计算机中,通过模式识别技术进行识别处理,形成文本文件,并转换成数据库文件。用VB程序设计语言编写灵活高效的档案管理系统,从而实现档案信息高效、快速、准确地录入计算机中,消除了工作中由于人的主观因素造成的错误。

一个面向OA的印刷汉字OCR实用系统

本文叙述一个采取以“统计模式识别”为主,以“结构模式识别”方法为辅的识别技术路线实现的以办公室自动化(OA)为应用环境的一级印刷汉字文本识别系统。该系统从实用化角度出发,采用页式文本图象扫描输入。输入后将图象文本分割成单个汉字,并根据汉字的结构特点,抽取了汉字的内层,外层,局部等多个特征。识别采用多级分类方法。识别结果形成一个国标区位码文件。系统软件建立了一种与用户间的友好界面。该系统是在IBM PC/XT上实现的,对印刷字样识别率>99％,对各类实际的办公行文其统计识别率>95％,识别速度为1～2字/秒。

Extremely active catalysts for the hydrogenation of terminal alkenes

Titanocene complexes combined with nanometer-size sodium hydride are extremely active and selective catalysts for the hydrogenation of terminal alkenes under normal pressure. The initial turnover frequencies (TOFinitial) may reach 100-300 s(-1) in the hydrogenation of 1-hexene. The highest catalytic efficiency turnover (TO) reaches 1.5 x 10(5) in 2 h for the hydrogenation of styrene. These catalytic systems exhibit specific selectivity toward alkene substrates. Only terminal alkenes can be hydrogenated. No isomerization of carbon-carbon double bonds occurs during hydrogenation. A suitable substituent on the cyclopentadienyl ring of titanocene and the use of nanometric sodium hydride are key factors in the high efficiency of these catalytic systems. (C) 2002 Elsevier Science.

Highly enantioselective resolution of terminal epoxides using polymeric catalysts

Poly-salen-Co(III) complexes were employed in the hydrolytic kinetic resolution (HKR) of terminal epoxides and ee's up to 98% were obtained. In the HKR of epichlorohydrin, the polymeric catalysts can be recovered and modified for recycling. The recovered polymer catalyst shows good activity and selectivity. (C) 2002 Elsevier Science Ltd. All rights reserved.