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A sensitive bioassay for estimating the activity of Trichosanthin was developed by using intraoocyte microinjection as the technique and germinal vescicle breakdown as a marker. The GVBD inhibitory activity assay was million-fold more sensitive than the routinely used abortifacient activity assay. The detectable amount of Trichosanthin ranged from 0.5 to 100 pg. Since the least detectable dose was 0.5 pg, it made the assay suitable to analyse the microquantity of pure Trichosanthin used for studying the structure and function of the drug. 相似文献
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问题 问题61 笔者在教学中,遇到了这样一个有趣的问题,同学们给出了三种不同的解法,都认为自己的解法有道理.然后,我们几个老师在一起讨论,也有所分歧.现请贵刊予以讨论.题目 设函数y=F(x) ,其定义域为[0 ,+∞) ,值域为R,已知F(x2 - 2 mx+ m+ 2 )的值域为R,求m的取值范围.解法1 令f(x) =x2 - 2 mx+ m+ 2 ,则可转化为对任意x∈R,f(x)≥0恒成立.故Δ=4 m2 - 4(m+ 2 )≤0 ,∴- 1≤m≤2 .解法2 由题意,y=f(x)的图象与直线y=0相切,即f(x)的最小值为0 (x∈R) .故Δ=4 m2 - 4(m+ 2 ) =0 ,∴m=- 1或m=2 .解法3 由题意,只要保证f(x)能取遍… 相似文献
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数值求解二维Euler方程的有限体积法(如k-exact,WENO重构、紧致重构等),无一例外地要进行耗时的网格单元上的二维重构.然而这些二维重构最后仅用于确定网格单元边界上高斯积分点处的解值,单元上二维重构似乎并非必需的.因此,文章提出用网格边上的一维重构来取代有限体积法中网格单元上的二维重构,分别在一致矩形网格和非结构三角形网格上发展了基于网格边重构的求解二维Euler方程的新方法,称为降维重构算法.数值算例表明该算法可以计算有强激波的无黏流动问题,且有较高的计算效率. 相似文献
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In tokamak plasma fueling, supersonic molecule beam injection(SMBI) with a higher fueling efficiency and a deeper penetration depth than the traditional gas puffing method has been developed and widely applied to many tokamak devices.It is crucial to study the transport dynamics of SMBI to improve its fueling efficiency, especially in the high confinement regime. A new one-dimensional(1D) code of TPSMBI has also been developed recently based on a six-field SMBI model in cylindrical coordinate. It couples plasma density and heat radial transport equations together with neutral density transport equations for both molecules and atoms and momentum radial transport equations for molecules. The dominant particle collisional interactions between plasmas and neutrals, such as molecule dissociation, atom ionization and charge-exchange effects, are included in the model. The code is verified to be correct with analytical solutions and also benchmarked well with the trans-neut module of BOUT++ code. Time-dependent radial transport dynamics and mean profile evolution are studied during SMBI with the TPSMBI code in both slab and cylindrical coordinates. Along the SMBI path, plasma density increases due to particle fuelling, while plasma temperature decreases due to heat cooling. Being different from slab coordinate, the curvature effect leads to larger front densities of molecule and atom during SMBI in cylindrical coordinate simulation. 相似文献
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飞行器在大气层内高速飞行时,高速气体来流在飞行器顶端形成高温高压气体绕流,并对顶端光学探测窗口形成强烈气动加热,光学窗口温度急剧上升,高温气体和光学窗口的红外辐射对探测系统形成严重的气动热辐射效应,探测信噪比下降。针对非灰混合气体和光学窗口材料的辐射特点,采用介质辐射传输方法,模拟了钝锥球头外形头部且顶端安装探测窗口飞行器的气动热辐射,研究了气体和窗口热辐射随时间的发展及其与窗口材料的关系。结果表明,高温气体的热辐射与飞行器的运动状态关系密切,而光学窗口的热辐射随飞行时间增加而迅速增强,逐渐成为气动热辐射的主要因素,因此抑制光学窗口的温度上升速度和幅度是减弱气动热辐射的关键。 相似文献
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