醋酸氟氢可的松片的研制

采用粉末直接压片法,通过处方筛选、工艺优化及体外药物释放特征研究,进行醋酸氟氢可的松片的研制.以纤维素-乳糖复合辅料作为稀释剂、硬脂酸镁作为润滑剂,进行混合压片,测定自制制剂的溶出曲线,采用f2相似因子法评价自制制剂和参比制剂的体外释放曲线.硬脂酸镁最佳用量为0.5％、片剂最佳硬度为60～80 N,在优化条件下,自制制...     

卷积完全匹配层在两维声波有限元计算中的应用

将基于复坐标变换和复频移扩展坐标变量的卷积完全匹配层Convolution Perfectly Machted Layer(CPML)引入到两维声波方程的有限元(FEM)计算中,该匹配层作为一种吸收边界条件Absorbing Boundary Condition(ABC)应用在有限元计算的边界截断上。文中分别给出了频域和时域的CPML方程的表达形式,并在有限元计算软件COMSOL中完成数值计算。相对于经典的PML,CPML最大的优势在于它不需要把场分裂开,这使其具有更好的稳定性和更高的吸收性能,且更易于实现。数值计算结果表明,CPML边界层有着比PML更好的吸收效果,其更有效的吸收了进入其中的声场能量。     

倍半硅氧烷合成进展

对以苯基三氯硅烷、苯基三烷氧基硅烷、甲基三氯硅烷、甲基三烷氧基硅烷、甲基三乙酸基硅烷分别为原料采用碱催化平衡水解三步法合成可溶性高分子量聚倍半硅氧烷及其共聚物进行了综述,并对以苯基三氯硅烷为原料采取一步法合成热塑性聚苯基倍半硅氧烷予以介绍,总结了以不同有机基为原料采用碱催化平衡法合成不溶性立方体聚倍半硅氧烷的研究结果,最后对卤盐催化非水解so-l gel 法制备有机倍半硅氧烷凝胶作了阐述,以期对合成不同结构的聚倍半硅氧烷提供帮助。     

新型间苯二酚杯芳烃硫脲衍生物对阴离子的识别

通过间苯二酚杯芳烃连续三步反应, 以较高产率合成了分子中连有8个和12个硫脲端基的间苯二酚杯芳烃的酰胺衍生物. 用紫外可见光谱法研究了两个代表性化合物4,6,10,12,16,18,22,24-八[6-(苯基硫脲基)-己氨甲酰基甲氧基]-2,8,14,20-四苯基杯[4]间苯二酚芳烃(THBC)和4,6,10,12,16,18,22,24-八[2-(苯基硫脲基)-1-甲基乙基-1-氨甲酰基甲氧基]-2,8,14,20-四苯基杯[4]间苯二酚芳烃(TPBC), 对各种阴离子(AcO^－, H₂PO₄^－, HSO₄^－, H₂PO₄^2－, C₁₂H₂₅-C₆H₄-SO₃^－, Cr₂O₇^2－, B₄O₇^2－, Cl^－, Br^－)的识别性能, 结果表明它们对AcO^－, H₂PO₄^－, HSO₄^－等阴离子有较好的配位作用, 能形成1∶3的配合物.     

一种新的WDM光网中的共享链路保护策略

研究了WDM光网中的链路保护问题.提出了一种新的共享链路保护策略--基于SRLG的共享链路保护策略(SRLG-SLP).SRLG(共享风险链路组)定义了对一条工作光通道分配保护资源时的资源可用性的约束.它规定任意两条有着同样故障风险或者说处于同一个SRLG的工作光通道不能利用同样的保护资源.另外,还提出了一种更加符合实际的单链路故障模型,其中链路故障间隔时间和链路故障保持时间被考虑作为两个独立的变量.基于该链路故障模型,通过大量的仿真试验,比较了专用链路保护(DLP)、共享链路保护(SLP)和提出的SRLG-SLP保护策略的资源利用率、保护效率以及业务中断率.结果显示,我们提出的SRLG-SLP在保护效率和业务中断率方面的保护性能远好于DLP和SLP,但会牺牲一些资源利用率.     

Low Timing Jitter and Tunable Dual-Wavelength Picosecond Pulse Generation from a Fabry--Pérot Laser Diode with External Injection

A novel scheme to generate tunable dual-wavelength optical pulses with low timing jitter at arbitrary repetition rates is proposed and demonstrated experimentally. The pulses are generated from a gain-switched Fabry-Pérot laser diode with two external cw beams for injection seeding simultaneously. The cw light is generated by two independent distributed feedback laser diodes, and their wavelengths can be tuned independently by two temperature controllers. The dual-wavelength pulses with the pulse width of 57 ps, the timing jitter of 340 fs, are obtained. The sidemode-suppression ratio of the output pulses is better than 23dB over a 10-nm wavelength tuning range.     

功能梯度圆板的轴对称自由振动

基于三维弹性理论,用直接位移法求解了横观各向同性功能梯度圆板的轴对称自由振动,其材料特性沿板厚度方向按指数形式变化．在弹性简支和刚性滑动两种边界条件下得到了三维精确解,即它逐点满足基本方程和边界条件．最后给出了数值算例并与以前的工作进行了对比．该方法也可推广应用于材料特性沿板厚度任意变化情形．     

强流ECR离子源引出系统研究

为了提高强流ECR 离子源的引出束流品质,分别设计了1# 和2# 引出系统,利用束流引出模拟软件PBGUNS 对1# 和2# 引出系统进行了质子束流引出与传输的模拟计算,结合实际测得的发射度数据分析引出系统,发现2# 引出系统比1# 引出系统引出束流品质高。对ECR 离子源引出系统的电势等位线分布等参数引起的球差进行了简单数学推导及MATLAB 绘图,并结合1# 和2# 引出系统束流相图模拟结果证明了球差会使引出束流品质有效发射度增长,通过适当加大电极孔径可改善束流聚焦情况,得到了束流光学聚焦较好的束流引出系统设计。To improve the quality of extracted ion beam from a high current ECR ion source, 1# and 2# extraction systems were designed and tested. The PBGUNS code was used to simulate the 1# and 2# extraction systems of proton ion beam. The emittance measurement results with the two different extraction systems were compared and analyzed with the simulation, the conclusion that more high quality beam extracted from 2# system than 1# system was got. The formula derivation of ECR ion source extraction system spherical aberration and MATLAB drawing was done by the analyzing on the distribution of extraction field equipotentials, effective emittance increasing caused by spherical berration was proved by 1# and 2# extraction systems beam phase space simulation result, beam focusing would be improved if electrode hole size increasing appropriately and a general concept on good optics focusing of ion beam extraction system was proposed finally.     

2.45 GHz ECR离子源的微波阻抗匹配

ECR离子源的等离子体阻抗对其微波传输与阻抗匹配设计至关重要。在中国科学院近代物理研究所现有的2.45 GHz ECR 质子源上,对等离子体阻抗进行了测量。首先用水吸收负载代替等离子体负载测量得到了所用微波窗阻抗,然后根据质子源测量数据,推算得到了等离子体阻抗。实验结果表明,脊波导输出端阻抗与后续负载不完全匹配,等离子体阻抗随微波功率变化呈非线性。这些结果为ECR离子源过渡匹配和微波窗的设计提供了参考依据。Plasma impedance of an ECR ion source is important for microwave transmission and impedance matching design. Plasma impedance was measured indirectly with the 2.45 GHz ECR proton source at the Institute of Modern Physics, Chinese Academy of Sciences. In the test, we got microwave window mpedance by using water absorption load instead of plasma load, and the source plasma impedance was derived from the test data with the 2.45 GHz ECR proton source and microwave window impedance. The experimental results show that ridge waveguide output impedance and the subsequent load does not exactly match, plasma impedance variation is nonlinear with microwave power. The achievedresult is useful in the design of ridged waveguide and microwave window.     

Zr基载体负载Pd催化剂用于贫燃天然气汽车尾气净化

 采用共沉淀法制备了 ZrO2, Y0.1Zr0.9Ox, Ce0.1Zr0.9Ox 和 Al0.1Zr0.9Ox 系列 Zr 基载体, 并用 N2 吸附-脱附和 X 射线衍射对其进行了表征. 再以此为载体, 采用浸渍法制备了整体式负载 Pd 催化剂, 催化剂涂层的涂覆量为 180 g/L 左右, Pd 含量为 1.25%. 测定了催化剂上 Pd 的分散度. 在模拟的贫燃天然气汽车尾气中考察了催化剂的活性, 并在尾气中有或无 SO2 存在的条件下比较了催化剂活性的差异. 结果表明, Y3+, Ce4+ 或 Al3+ 改性载体负载的 Pd 催化剂的耐硫性能明显改善; 无论尾气中是否存在 SO2, 以 Y3+ 或 Al3+ 改性载体负载的 Pd 催化剂的活性均明显高于 ZrO2 负载体的 Pd 催化剂.