预定点拍摄胸部前凸位相（前后位摄影）的经验介绍

预定点拍摄胸部前凸位相（前后位摄影）的经验介绍高宏海在基层单位，使用一般的Ｘ线机摄影，通常仍采用长尺作为校正中心线的工具。在作远距离球管倾角摄影时，觉得不甚方便，费时而缺乏准确性。为此，笔者设想预定点摄取胸部前凸位相，即经过预先测量，找出球管水平时与...

雷达模拟器标绘的数学解析

在雷达模拟器训练评估体系研究中 ,给出目标船的 6要素 (即目标船的 CPA,TCPA,距离 r( t) ,方位 θ( t) ,目标船的真航速 VT和真航向 CT)的解析式及 C语言计算程序 ,作为雷达模拟器训练评估体系的标准值 .同样 ,在雷达标绘的训练中 ,也需要有标准值 .文中试图给出雷达标绘的数学解析 .它包括避让措施的求取简称预定点改向 /变速问题和改向 /变速后恢复原航向 /原航速时机点的求取 ,简称时机点问题 .经计算机编程后可以迅速地得到避让措施所需要的数值 ,一方面它提供了雷达模拟器训练时评估的基准值 ,另一方面它将避免几何作图时间长 ,误差大的缺点 。

Luminescent properties dependence of water-soluble CdTe quantum dots on stabilizing agents and reaction time

The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It is found that larger-size QDs can be synthesized more easily when L-cysteine(Cys) or golutathione(GSH) is chosen as stabilizing agent and TGA is proper to prepare highly luminescent QDs because of the effect between Cd2+ and sulfhydryl group.Furthermore,the absorption wavelength,full width at half maximum(FWHM),stokes shift,photoluminescence(PL) quantum yield and PL stability of TGA-CdTe are strongly dependent on reaction time,in which the absorption wavelength changes against reaction time with an exponential function.The TGA-CdTe QDs prepared at 2 h possess more excellent luminescent properties.