水溶液中[Tc(tu)_6]~(3+)与柠檬酸反应研究

采用UV－Vis吸收光谱法研究了在水溶液中三价锝硫脲配合物（[Tc(tu)6]^3 ）与柠檬酸（cit)之间的配体取代反应，测定了反应生成物的组成比，并用电泳方法确定了产物的电荷性质。实验结果表明，配体取代反应第一阶段的产物中Tc和cit的化学计量比为1：1，产物在电泳实验中滞留于原点，表明产物呈电中性。文章给出了[Tc(tu)6]^3 与cit的反应速率方程。     

Multiphase analysis of Bi-Sr-Ca-Cu-O high Tc superconductors with x-ray compositional mapping

Ba-Sr-Ca-Cu-O (BSCCO) high Tc superconductor specimens were prepared as part of a solid-solubility study in the region of the 2223 phase. The identification and determination of the amount of each phase in the final products were necessary. Quantitative digital x-ray compositional mapping with the electron microprobe was done with five wavelength spectrometers, one for each of the cations. To facilitate phase identification and quantification, image processing rules were developed for the nine possible phases, with each assigned a unique color. Using this procedure, at least six different phases were identified. Examples are cited in color.     

Quantitative evaluation of perpendicular‐field losses in stacked high‐Tc superconducting tapes

The influence of stacks of Bi‐2223 multifilamentary tape‐shaped wires without twisting on AC losses observed in an external magnetic field perpendicular to their wide faces is investigated. The perpendicular‐field losses decrease with increasing number of tapes in the range of small field amplitudes. At larger amplitudes, on the other hand, the AC losses have little dependence on the stack number. This can be attributed to the effect of magnetic interaction between wires. By taking into account effective demagnetization factors on the basis of theoretical consideration, the perpendicular‐field losses are plotted on a master curve for the maximum magnetic field applied to the wires. Furthermore, the perpendicular‐field losses measured as a function of the field amplitude are well reproduced by the numerical evaluation of AC losses for a slab with infinitely wide surfaces. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(3): 50–57, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10050     

近紫外芯片激发三基色荧光粉制作的白光LED

使用近紫外半导体芯片激发红绿蓝三基色荧光粉,制作了白光发光二极管（LED）,并研究了其光电特性。结果表明,采用发射峰值波长分别在613、495和451nm的红绿蓝荧光粉,在波长400nm左右半导体芯片激发下的白光LED,其显色指数Ra最大为82;使用YAG荧光粉代替绿色荧光粉后,Ra提高到93。测试结果还表明,当工作电...     

高温超导材料在舰船上的应用

本文概述了高温超导(HTS)材料在舰船上的应用研究现状和发展趋势,包括超导电缆、超导电机、超导扫雷具、电磁弹射/发射装置和储能系统等。     

裂变~(99)Mo-~(99m)Tc发生器γ核纯质量控制

~(99)Tc是目前在核医学上应用最广泛的放射性示踪核素。它发射的140 keVγ射线不但容易准直,而且足够用作人体内深部器官显像。由于它的半衰期比较短(6.02 h),γ射线能量也较低,所以对病人的剂量比较小。通常,~(99)Tc系用生理盐水淋洗~(99)Mo-~(99)Tc发生器获得,在淋洗下大量~(99m)Tc的同时,一些杂质也不同程度地淋洗下来了。显然,~(99m)Tc淋洗液中的其它放射性杂质应该尽     

Tc(Ⅶ)与Re(Ⅶ)在TEVA 及AG1-X4树脂上的化学行为相似性

样品中⁹⁹Tc的测定需经过预处理及化学分离纯化等过程,由于流程复杂,往往存在锝的损失,因此选择合适的示踪剂是准确测定锝含量的关键。本工作采用静态法与柱实验相结合,分别研究了固相萃取树脂TEVA及离子交换树脂AG1-X4对样品中⁹⁹Tc的分离纯化条件,探究了Re和Tc在化学分离纯化过程中的行为相似性。结果表明：TEVA及AG1-X4树脂对ReO^-₄和TcO^-₄都有着较强的吸附能力,选择pH为9～11范围上柱,采用高浓度HNO₃洗脱,Re和Tc的化学行为基本一致,且回收率均在90%以上。通过控制实验条件,可利用Re作为Tc的稳定非同位素化学类似物获取⁹⁹Tc在分析流程中的化学回收率。     

Mo元素对铁镍热磁合金性能的影响

为了进一步提高铁镍热磁合金的性能,系统研究了Mo元素对铁镍热磁材料的磁滞回线、Ms-T曲线和热磁性能的影响规律.结果表明:随Mo含量的增加,Fe65.84-xNi34.16Mox(x＝2,3,4,5)合金的磁滞回线逐渐变得扁平,饱和磁感应强度值(Bm)、饱和磁化强度值(Ms)和居里温度(Tc)单调下降,温度系数△B/△T(0～100℃)值呈先升高后降低的趋势,并在Mo含量为4at%附近出现最高值5.86mT/℃.     

锝标记长链脂肪酸衍生物(BAT-FA)的初步研究

放射性药物研究中,用~(123)I标记长链脂肪酸及其衍生物已有很多报道。本文报道了三种锝标记的长链脂肪酸衍生物:Tc-BAT-TDA,Tc-BAT-PDA和Tc-BAT-HxDA。三者的~(99m)Tc标记物均可用配体交换反应制备,产额分别为87％,70％和49％。产物经萃取纯化,放化纯高于98％。以~(99)Tc为载体,制备了~(99)Tc标记物,红外、紫外光谱的Tc=O特征峰与已知~(99)Tc-BAT络合物的光谱数据相符。动物实验数据表明:~(99m)Tc标记的上述长链脂肪酸衍生物在心脏中的浓集程度较碘代苯基十五酸(IPPDA)低。静脉给药后5min,在大鼠心肌中分别为0.20％,0.32％和0.46％剂量/组织。药物大部分浓集于肝脏。所提出的三种Tc-BAT-FA尚不能满足做为心肌显像剂的要求,需要通过改善配体的结构等途径来获得更好的结果。     

经Avidin—Biotin系统^99mTc标记单抗及其在荷瘤裸鼠体内分布研究

采用Ａｖｉｄｉｎ－Ｂｉｔｉｎ系统进行了抗人黑色素瘤单抗Ｎｇ７３的＾９９ｍＴｃ标记、研究了标记条件，方法和标记抗体在荷裸鼠活体内的生物学分布１。结果表明，ｐＨ＝８和ＳｎＣｌ２适量时标记效果最好；两步法Ｂ的Ｔ／ＮＴ和ＩＤ％／ｇ值均明显优于两步法Ａ。经Ａｖｉｄｉｎ－Ｂｉｏｔｉｎ系统＾９９ｍＴｃ标记单抗可用于放射免疫显像。