变螺距螺旋曲面线切割加工探讨

通过变螺距诱导轮的加工，从加工原理、数学模型的建立及程序编制，提出了线切割加工变螺距螺旋曲面的一种方法。     

变螺距螺旋曲面线切割加工探讨

通过变螺距诱导轮的加工，从加工原理，数学模型的建立及程序编制，提出了线切割加工变螺距螺旋曲面的一种方法。     

茯苓聚糖的氚离子束标记及其在小鼠体内的药物动力学研究

本文采用氚离子束标记法,对茯苓聚糖进行了标记,放射性比活性达1.81—2.07TBq/mmol。药物动力学研究证明~3H-茯苓聚糖尿素液口服灌喂小白鼠,按一定时间在尾部静脉取血样作放射性分析。得到的药-时曲线适合于双定模型。     

氚离子束标记新技术

本文介绍一种先进的氚离子束标记技术,用于蛋白质、肽和非挥发性有机化合物的氚标记。在该技术中,加速受激发的氚离子束,去轰击固体样品,发生氢-氚交换反应。氚化大豆胰蛋白酶抑制剂、核糖核酸酶A、弹性蛋白和茯苓聚糖等十一种化合物已用此法输备。氚化粗产物经透析、离子交换色层和凝胶过滤等方法纯化后,蛋白质和聚糖的比活性一般可达37GBq/mmol以上,没有放射性副产物和具有与天然物质相同的生物活性。氚化蛋白质的氨基酸分析表明,在蛋白质中,His、Tyr和Phe残基具有较高的比活性而Val、Ile和Ser残基的比活性较低。     

回转端面曲线型面的线切割加工

波浪型弹簧片是产品中的一种零件。压制该零件的模具(见图1)要求在端面上加工出三等分的按正弦曲线规律变化的型面。如在铣床上加工需用分度头与转盘相连,同时要实现机床台面的往复运动。这样,为达到零件精度要求就要使机床丝杆传动间隙做到最小,对转接齿轮精度要求也较高(要经过磨齿工序),这些条件我们不具备。而且,即使条件具备,电加工不出符合设计要求的零件。所以,原加工工艺是在铜皮上画出曲线(实际上是以圆弧代替的),再包在零件φ39外径上划线,经铣加工。最后由手工锉修完成。这样加工出的模具,型面不准,等分不好,上、下模     

L-脯-L-亮-甘氨酰胺(PLG)的离子束氚标记及其在鼠脑内的分布

本文用离子束氚标记技术制得氚标记PLG。经磋胶纸层析法纯化,氚化三肽的比活度为6.81GBq/mmol,放化纯度>95％,具有完全的生物活性。由腹腔注射~3H-PLG,直接测定大鼠脑内部分组织的放射性分布,提示用药4.5h后,垂体、纹状体有较高的放射性,而下丘脑和中脑的放射性较低。     

SYNTHESIS OF (~3H-METHYL) TRINITROTOLUENE AND ITS APPLICATION TO TOXICOLOGICAL STUDY

In this paper, (2H- methyl) toluene was prepared by catalysed halogen- tritium substitution method from benzyl bromide, then it was nitrated to produce (8H- methyl) trinitrotoluene. The tritiated product was purified by thin- layer chromatography. At last, the pure 3H- TNT was obtained with specific radioactivity of 3.77 GBq/mmol. Radiochemical purity was over 98% and the ultraviolet absorption spectrum of tritiated TNT was conformed with that of standard sample. Using 3H- TNT as a tracer, its toxicokinetics was sudied in rats. The results showed that the toxicokinetics characteristics of TNT were quickly absorbed into the blood, Vd>2L/kg.h, long T1/2β and fixed accumulation with four routes of administration, TNT and its metabolites were mainly excreted by the urine. The half- life of TNT in the urine were 1,1- 24h. A trace of radioactivity of 3H- TNT and its metabolites could be detected in the urine on 7th day after administration (9.25×106Bq/kg).