Langendorff灌流心脏的31P NMR谱测定

测定了Langendorff灌流大鼠和兔心脏的³¹P NMR谱.观测到PCr、ATP、SP、P_i以及PME和GPC等含磷代谢物的共振峰,各谱峰之间实现了很好的分辨.在3~5min的累加时间内测得的图谱具有较好的S/N,可用于以上含磷代谢物的定量测定,以高能含磷化合物ATP和PCr相对峰强度以及冠脉流量的变化对灌流大鼠心脏代谢的稳定性进行了考察,结果表明,在本实验条件下大鼠心脏的能量储存至少可稳定2h,用所建方法以3min的时间间隔对同一大鼠心脏缺血21min及再灌注12min过程中心脏的³¹P NMR谱进行了连续跟踪测定,并初步观测了缺血及再灌注过程中心肌细胞内ATP、PCr与P_i之间的消长关系.     

大气弱湍流下星地光链路衰落特性影响因素分析

研究了弱湍流条件下星地光通信链路的衰落概率、平均衰落次数以及平均衰落时间3个重要参数的统计特性,并通过数值仿真分析了链路天顶角、光波长以及接收机海拔高度对链路衰落特性的影响。结果表明:减小天顶角和提高接收机探测灵敏度可以改善链路的衰落特性;1.55 m激光较0.85 m、1.06 m激光更适合于星地光通信;地面接收机应尽量建在2 000 m以上的高海拔地区。     

超薄前投激光显示系统研制

为了解决光学系统投影厚度过大问题,采用自由曲反射面结合非球面设计方法设计出超短距离、超广角投影显示系统,其屏幕投影距离小于20 cm。为解决激光色域系统转换,建立了激光三基色与荧光粉三基色色域变换与扩展的理论模型并搭建了基于DSP高速图像处理芯片为核心的颜色变化实时硬件处理试验开发系统。通过该系统可以调试不同颜色系统转换算法,验证转换模型的正确性,并为实现专用颜色转模块提供了开发平台。     

基于MSP430单片机的自动灌溉演示装置

介绍了基于MSP430F149单片机的自动灌溉演示系统的软硬件设计.该系统通过单片机控制温湿度传感器和光强传感器,实现对环境相对湿度、温度、光强实时采集与处理,演示自动灌溉植物.     

A 2-dimensional gradual period photonic heterostructure possessing omnidirectional band gap in visible range made by holography

A 2-dimensional gradual period photonic heterostructure was made with holography by use of non-uniform swelling effect of dichromated gelatin during processing. In this structure, the symmetric point group of triangle lattice was debased to C_2V from C_6V. Theoretical analysis and experimental results show that omnidirectional band gap in visible range can be achieved with this kind of heterostructure made by low refractive index materials.     

The study on neural contrast sensitivity function at temporal frequencies

The neural contrast sensitivity function (NCSF) of human eye at temporal frequencies is acquired with a new method in this paper. Firstly the human eye's contrast sensitivity function (CSF) at temporal frequencies is measured by means of travelling-wave stimuli, and the modulation transfer function (MTF) of the eye's optics is obtained by constructing the eye model of the subject. Then the NCSF at temporal frequencies is calculated with the two functions. It is shown that the overall value of the NCSF decreases as the temporal frequency increases. As the temporal frequency increases from 0 cycles per second (c/s) to 1 c/s, 16 c/s and 30 c/s, the NCSF curve changes from the band-pass shape to the low-pass, and then to almost monotonic variation. The attenuation factor of the NCSF, which represents the sensitivity of visual neural system to the temporal frequency, varies little as spatial frequency increases, while that of the CSF declines dramatically in the region of high spatial frequencies. Because it is the NCSF, rather than the CSF, that reflects the characteristics of visual neural system, the investigation of the NCSF at temporal frequency is more essentially.     

大幅提高视觉密度国家基准测量水平的方法研究

随着生物医学影像和航天军事测量的发展,对用于光学成像底片和视觉校正的视觉密度的测量范围和不确定度的要求越来越高.以自行设计的光纤半球发射器形成的复合漫射器为特征的新方案将视觉漫透射密度国家基准的光源漫射系数提高到0.945,比欧美国家基准高0.02—0.03.实验得到新基准的测量范围为0—6.0,合成不确定度为0.0015(0相似文献   

Field-assisted spin-polarized electron transport through a single quantum well with spin-orbit coupling

We have investigated theoretically the field-driven electron transport through a single-quantum-well semiconductor heterostructure with spin-orbit coupling.The splitting of the asymmetric Fano-type resonance peaks due to the Dresselhaus spin-orbit coupling is found to be highly sensitive to the direction of the incident electron.The splitting of the Fano-type resonance induces the spin-polarization dependent electron current.The location and the line shape of the Fano-type resonance can be controlled by adjusting the energy and the direction of the incident electron,the oscillation frequency,and the amplitude of the external field.These interesting features may be used to devise tunable spin filters and realize pure spin transmission currents.     

氯苯的同步辐射光电离研究

利用真空紫外同步辐射和反射式飞行时间质谱仪对氯苯进行了光电离研究,通过测量各离子的光电离效率(PIE)曲线,得到了氯苯的电离势为(9.11±0.05)eV及两种主要碎片离子C6H+5和C4H+3的出现势分别为(12.96±0.05)和(16.27±0.05)eV.结合有关文献的热力学数据,推导出C6H5Cl+、C6H+5及C4H+3的离子生成焓及一些键的解离能.实验获得了118.0nm同步辐射光电离下氯苯的质谱图.