Optimal design of a 7 T highly homogeneous superconducting magnet for a Penning trap

A Penning trap system called Lanzhou Penning Trap (LPT) is now being developed for precise mass measurements at the Institute of Modern Physics (IMP). One of the key components is a 7 T actively shielded superconducting magnet with a clear warm bore of 156 mm. The required field homogeneity is 3 x 10(-7) over two 1 cubic centimeter volumes lying 220 mm apart along the magnet axis. We introduce a two-step method which combines linear programming and a nonlinear optimization algorithm for designing the multi-section superconducting magnet. This method is fast and flexible for handling arbitrary shaped homogeneous volumes and coils. With the help of this method an optimal design for the LPT superconducting magnet has been obtained.

Interaction between netropsin and double-stranded DNA in capillary zone electrophoresis and affinity capillary electrophoresis

Capillary zone electrophoresis (CZE) and affinity capillary electrophoresis (ACE) were applied to study the interaction between netropsin and a 14mer double-stranded DNA (dsDNA). The use of a polyacrylamide coated capillary can suppress the electroosmotic flow (EOF) and the adsorption of DNA onto the wall. Better analysis of the DNA was achieved in a coated capillary upon Tris-acetate. In CZE, the peak width broadened due to the affinity interaction between dsDNA and netropsin. In ACE, o-toluic acid, a negatively charged molecule was used as the indicator to monitor the changes of EOF when netropsin was added to the running buffer. The 14mer dsDNA showed different mobilities upon various concentrations of netropsin due to the affinity interaction between the dsDNA and netropsin. The binding constants of this interaction were (1.07 +/- 0.10) . 10(5) M-1 calculated from CZE and (4.75 +/- 0.30) . 10(4) M-1 from ACE using a Scatchard plot. The binding stoichiometry was 1:1 calculated from CZE which was superior to ACE in this study. (C) 2002 Elsevier Science B.V. All rights reserved.

陕北丘陵沟壑区果树适地适栽与节水灌溉

根据陕北丘陵沟壑区川地、坡地以及不同坡向、不同坡位的气候条件 ,提出果树的最佳适栽地块。通过对陕北丘陵沟壑区果园土壤含水量的分析 ,提出了适合于该区的果树节水灌溉方法和灌溉量

香港植物水分生理学和水土保持专家 张建华博士

张建华 ,男 ,1 95 6年出生于江苏省金坛县 ,1 982年毕业于江苏农学院 (现为扬州大学 )农学系农学专业。 1 985年赴英国进修 ,1 988年在英国兰卡斯特大学获博士学位 ,1 988— 1 991年在该校受聘继续做博士后研究员。一直从事植物根土关系及缺水条件下根系感知土壤缺水信号传递研究工作。已在国内、外学术刊物上发表论文 70余篇 ,其中 SCI期刊论文 5 0余篇 ,并被国际上许多同行专家多次引用 ,受邀撰写综述1 0余篇 ,参加各类国际会议 2 0余次 ,特别是受《Annual Review of Plant Physiologyand Molecular Biology》编辑部邀请 ,与导师合作发表综述 (1 991 )文章 ,以自己的系统研究为基础 ,对植物感知土壤干旱信号及其生长发育调节做了详细评述 ,是根源信号理论体系建立的代表性论文 ,构成了目前根信号理论体系的基础 ,被认为是该研究领域最为重要的论文。现已被国内外多种教科书引用和介绍。另外在国际著名植物生理学家 W.J.Davies指导下 ,在英国兰卡斯特大学攻读博士期间于 1 987年在植物学界享有盛誉的《Journal o...

四甲基乙二胺、过硫酸铵体系产生的活性氧对固氮酶（钼铁蛋白）损伤初步研究

四甲基乙二胺、过硫酸铵体系产生的活性氧对固氮酶（钼铁蛋白）损伤初步研究赵云峰，杨峰，林永齐（吉林大学，长春１３００２３）杨俊森（中国科学院沈阳应用生态研究所，沈阳１１００１５）林海（中国科学院长春物理所激发态物理开放实验室，长春１３００２２）生物固氮...

土壤资源信息共享的WEBGIS实现

如何使用和共享现有的土壤科学数据一直是一个重要问题。为提高土壤资源信息的共享和利用效率,文章阐述了在因特网环境下实现土壤资源信息发布的体系结构及关键技术,讨论了其实现方法。采用WebGIS技术,以ARCIMS为平台,以广东省土壤系列图件为基础,构建土壤信息共享系统,通过WEBGIS进行土壤资源信息的发布和共享,并介绍了系统的主要功能。

Controllable synthesis of highly luminescent and monodisperse CdS nanocrystals by a two-phase approach under mild conditions

Highly luminescent and monodisperse CdS nanocrystals (see Figure) have been synthesized using a two-phase approach. The synthesis of CdS nanocrystals at the liquid-liquid interface was easy, safe, and highly reproducible, and the reaction conditions were mild and controllable.

Unique structure and photoluminescence of Au/CdTe nanostructure materials

Unique nanostructure materials with highly ordered spherical aggregates have been obtained by self-organization of single CdTe nanocrystals using gold nanoparticles as seeds, and a red shift of the photoluminescence peak was observed.

自组装单分子膜包覆的金属纳米粒子的电化学研究

介绍了近年来自组装单分子膜包覆的金属纳米粒子这一领域的最新发展,包括单分子层膜包裹的纳米粒子的合成、衍生化、光学和电化学性质及应用,其中重点介绍了其量子化充电现象.对该领域的深入研究将大大地促进化学、生物科学、材料科学和纳米电子学等前沿学科的发展.

Electrooxidation of methanol on carbon nanotubes supported Pt-Fe alloy electrode

The synthesis and characterization of catalysts based on bimetallic materials, Pt-Fe supported on multi-walled carbon nanotubes (MWNTs) for methanol electrooxidation is reported here. The catalyst was prepared by a spray-cooling process and characterized by TEM, EDS, ICP and XRD. The electrocatalytic properties of the Pt-Fe/MWNTs electrode for methanol oxidation have been investigated by cyclic voltammetry and chronoamperometry. It presented higher electrocatalytic activity and stability than a comparative Pt/ MWNTs catalyst. This may be attributed to the addition of Fe which leads to the small average particle size and high utilization of Pt in the Pt-Fe/MWNTs catalyst. The results imply that the Pt Fe/MWNTs composite has good potential applications in fuel cells.

Sol-gel biosensor

yA review with 44 references is presented on the development of sol-gel-based biosensor. The main discussions are devoted to the process, advantages and properties of sol-gel immobilization method, sol-gel optical biosensor and amperometric biosensor, also the trend in this field is forecasted.

溶胶-凝胶生物传感器

评述了溶胶-凝胶(sol-gel)生物传感器这个领域已取得的成果,主要内容涉及溶胶-凝胶固定化方法的过程、优点与性质,溶胶-凝胶光学生物传感器和安培生物传感器的发展,并展望了其发展趋势.