STUDY ON THE CATHODE DEPOSIT PRODUCED IN THE PROCESS OF CARBON ARC DISCHARGE

The cathode deposit produced by carbon are discharge wae studied by scanning electron microscopy, high resolution electroa microscopy, X-ray diffraction and Raman spectroscopy. The results indicate that the stacking of hexagonal carbon layer in the discharged graphite is different from the ABAB stacking sequence in graphite, and that carboy nanotube is a kind of graphite-like micro-crystal with a low-dimensional structure.     

非共沸混合制冷剂在高温空调中的实验研究

分析了R22/R142b在高温空调系统中应用的可行性,实验研究了高温空调样机性能参数随制冷剂混合比变化的规律,确定了空调样机的最佳充灌量。实验表明:R22/R142b的质量比为6.6/3.4~7.0/3.0时,空调系统在较宽的环境温度范围(35℃—60℃)制冷量变化平坦,技术和经济性能理想,排气温度和压力在普通空调压缩机的安全范围;同时显示制冷剂充灌量为2.6kg左右时,空调样机的制冷运行性能较优。     

MICROSTRUCTURE AND LUMINESCENCE PROPERTIES OF GaxIn1-xP/GaAs HETEROSTRUCTURE

The Ga_xIn_1-xP/GaAs heterostructures with different x values have been investigated by photoluminescence (PL), energy dispersive spectrum (EDS), and transmission electron microscopy (TEM). Experimental results suggested that the composition of epitaxial layers evidently affected the microstructure of the heterostructures. When x value was close to 0.5, the defects in the epitaxial layer decreased, and the lattice match between film and sub-strate approached optimum, Meanwhile, the heteroatructure provided a high luminescence efficiency.     

快速检测大肠菌群数的研究

采用双倍料去氧胆酸钠-TTC-乳糖半固体培养基平板对食品中大肠菌群进行快速测定。并以乳糖发酵法为对照市场购得的10种食品中的大肠菌群数进行对比测试，实验显示：两方法结果一致都是9种为大肠菌群数合格食品，1种为大肠菌群数不合格食品。其符合率可达100%，而且平板培养法能在24h内获得大肠杆菌数结果，大大缩短了检测时间。     

网络入侵检测系统警报过滤算法设计

网络入侵检测系统OqIDS）大量的警报数据使得安全管理员在进行安全评估时，需要花费大量的精力，分析效率极低。NIDS之所以会有这样大量的警报数据主要是由于误报、重报或信息冗余度太大造成的。很多误报是可以找到原因或规律的，可以设计一种过滤算法将有规律的误报过滤掉，从而减少误报。在IBM苏黎世研究实验室相关研究工作的基础上，设计出了一种基于规则的警报过滤模型和算法。其模型见图1。     

球面波干涉法测量拉盖尔-高斯光的轨道角动量

采用球面波的拉盖尔-高斯光(LG光)和平面波的基模高斯光干涉的方法 ,可观察到多叶螺旋的干涉图样,螺旋的叶数即是LG光的拓扑荷数,由拓扑荷数可知光子的轨道角动量.利用涡旋相位片产生拓扑荷数1～8的LG光,研究了光强比和偏振条件对干涉图样的影响.为获得高对比度的干涉图样,要求LG光和高斯光的偏振方向相同并且光强基本相等.球面波干涉法用于测量LG光的轨道角动量简单直观,与干涉光强空间分布的细节无关,因此对光强扰动和背景噪声不敏感.     

MICROSTRUCTURE AND LUMINESCENCE PROPERTIES OF GaxIn1-xP/GaAs HETEROSTRUCTURE

The Ga_xIn_1-xP/GaAs heterostructures with different x values have been investigated by photoluminescence (PL), energy dispersive spectrum (EDS), and transmission electron microscopy (TEM). Experimental results suggested that the composition of epitaxial layers evidently affected the microstructure of the heterostructures. When x value was close to 0.5, the defects in the epitaxial layer decreased, and the lattice match between film and sub-strate approached optimum, Meanwhile, the heteroatructure provided a high luminescence efficiency.     

FeCr2-x GaxS4的磁性与巨磁电阻效应

研究了没有双交换作用的FeCr^2-x Ga_xS₄材料的磁性以及CMR效应.实验指出：Ga对Cr的替代破坏了Cr亚晶格自旋的相互作用,使体系FM性增强从而导致T_c提高,但PM到FM相变的幅度随掺杂逐渐降低.ESR给出的微观磁性指出Fe,Cr亚晶格自旋在温度低于T_c时各自是FM排列,而两者之间是AFM排列,以致对未掺杂样品,体系的宏观磁矩M相互抵消,掺杂样品在T_c将出现固有FM性. Ga掺杂使发生MR的峰值温度提高,但MR值降低.     

KH添加对Na-Al-H配位氢化物可逆放氢性能的影响

以NaH粉和Al 粉为合成原料, 分别采用2% (摩尔分数, x) CeCl₃和2% CeCl₃/y% KH (y=0.02, 0.04)为催化添加剂, 在室温和3 MPa氢压下, 通过反应球磨(NaH/Al+CeCl₃)和(NaH/Al+CeCl₃/yKH) (y=0.02, 0.04)复合物成功制备出Na-Al-H 配位氢化物. 吸放氢性能测试结果表明, KH的加入能有效改善Na-Al-H 体系中第二步脱氢反应放氢动力学性能. (NaH/Al+CeCl₃/0.02KH)复合物170℃放氢时可在20 min内完成脱氢过程, 且在较低温度(100-140℃)下具有良好的可逆吸放氢性能. Kissenger 方法计算表明, 添加KH可降低Na-Al-H 体系第二步脱氢反应的表观活化能, 降低其放氢峰值温度. 相结构分析表明, KH的添加使Na-Al-H 体系中Na₃AlH₆的晶胞体积发生膨胀, 进而提高体系的第二步放氢动力学性能.     

Analysis of normalized throughput in WDM-based coherent time-spreading OCDMA system

The performance of normalized throughput in wavelength division multiplexing （WDM） based coherent time-spreading optical code division multiple access （TS-OCDMA） system is studied. The upper bound and lower bound of normalized throughput are obtained with 8 wavelength channels and 127-length Gold code, and with 4 wavelength channels and 511-length Gold code respectively. It is shown that when all simultaneous users are equally allocated to different wavelength channels, WDM＋TS-OCDMA has much better performance. However, if there is no central control to allocate wavelength channels equally, WDM＋TS-OCDMA system has the in-between performance of normalized throughput.