Using Natural Cinchona Alkaloids to Promote the Enantioselective Addition of Dialkylzinc to N－Diphenylphosphinylimines

Cinchona alkaloids are utilized as chiral ligands to promote the enantioselective addition of dialkylzinc to N-diphenyiphosphinylirnlnes affording enantiomerically enriched N-diphenyiphosphinylamines in up to 91% ee.     

氟钒锰共掺对TiO2柱撑膨润土光催化脱硝性能的影响

采用溶胶-凝胶法制备氟钒锰共掺改性的TiO₂柱撑膨润土，使用XRD、氮吸附、UV-vis光谱和SEM等手段对其进行了表征测试，并对其室温下的可见光催化脱硝性能进行了评价研究。结果表明，对于NO质量浓度为661 μg/m³的气体，F-V-Mn共掺TiO₂柱撑膨润土的光催化脱除效率近似达到100%，而NO质量浓度提升至1657 μg/m³时，光催化效率为81.9%，与未柱撑的F-V-Mn共掺TiO₂相比提高了33.8%。F-V-Mn共掺TiO₂柱撑膨润土上光催化脱反应速率常数最大，是V-Mn共掺TiO₂柱撑膨润土的2倍，且前者的抗水和抗SO₂中毒能力也更强。TiO₂柱撑不仅保留了膨润土的片状晶体结构，而且使膨润土层间距由0.667 nm增大至0.710 nm，吸附能力增强；同时，掺杂元素能抑制TiO₂金红石相生长，降低TiO₂禁带宽度，提高可见光响应，延长使用寿命，拓宽应用范围。     

防空武器系统维修性分配的模糊规划方法

在探讨武器系统维修性的优化分配问题时,以往的维修性分配规划模型,常采用的是普通数学规划方法,而忽视了维修性分配所包含的模糊性因素。提出了维修性分配的模糊规划方法,并通过应用举例予以了说明。     

Observation of MWCNTs with low-energy electron point source microscope

The low-energy electron point source (LEEPS) microscope, which creates enlarged projection images with low-energy field emission electron beams, can be used to observe the projection image of nano-scale samples and to characterize the coherence of the field emission beam. In this paper we report the design and test operation performance of a home-made LEEPS microscope. Multi-walled carbon nanotubes (MWCNTs) synthesized by the CVD method were observed by LEEPS microscope using a conventional tungsten tip, and projection images with the magnification of up to 10₄ was obtained. The resolution of the acquired images is \sim10 nm. A higher resolution and a larger magnification can be expected when the AC magnetic field inside the equipment is shielded and the vibration of the instrument reduced.     

金属天线罩及闭合体电磁散射研究

本文利用金属表面的混合电磁边界条件以及天线罩的旋转对称性，对电大尺寸金属天线罩的RCS 进行了数值分析,比较了开放的天线罩与封闭天线罩锥球体的RCS 的区别。     

用正交态方法实现非绝热几何量子计算

精确求解了自旋1/2粒子在旋转磁场下的Bloch方程,并用旋转坐标系方法得到此系统的精确波函数。对演化波函数取绝热极限可得到Berry几何相,并将这些结果与Bitter等的慢中子实验做了比较。对旋转磁场下的一般AA循环,本文得到了Aharonov-Anandan(AA)总相位和几何相的解析结果。当采取正交态的一般方法,即取入射初态为等权重的两个正交态的叠加,可以证明非对角动力学相与非对角几何相同对角动力学相一样在任意时刻抵消,剩下几何相的对角部分。对匀速旋转的圆锥磁场,此几何相类似Berry几何相为时间的线性函数。最后也讨论了正交态方法和最近用实验实现非绝热几何量子门工作的关系。     

CAN总线在测绘相机控制器中的应用设计

为了实现测绘相机控制器与星务计算机之间的可靠数据通讯,对CAN总线在测绘相机控制器中的应用方法进行研究。首先,根据CAN总线工作原理对硬件电路进行设计,然后在对CAN总线控制器和TSC695的接口逻辑进行分析比较的基础上,采用状态机设计法解决接口时序的不匹配性问题,并利用Modelsim软件对状态机进行时序仿真与验证。最后介绍了CAN总线控制器初始化配置流程和定时状态设计方法。实验结果表明:相机控制器通过CAN总线以307.2 kb/s波特率通讯时无错误,CAN总线接口状态机的时序余量能够达到20%,满足测绘相机控制器CAN总线通讯的可靠性要求。     

南京普天为世博会通信保驾护航

南京普天与上海通信信息运营商建立战略合作伙伴关系,努力融入世博、服务世博、奉献世博,先后有普天综合布线、配线、A8基站及睿秀视频安保平台应用方案等四大系列产品全面参与上海世博建设,为上海世博会提供多种高效的通信保障与安全保障.     

Stable 85Rb micro vapour cells: fabrication based on anodic bonding and application in chip-scale atomic clocks

We describe the microfabrication of 85 Rb vapour cells using a glass-silicon anodic bonding technique and in situ chemical reaction between rubidium chloride and barium azide to produce Rb.Under controlled conditions,the pure metallic Rb drops and buffer gases were obtained in the cells with a few mm 3 internal volumes during the cell sealing process.At an ambient temperature of 90 C the optical absorption resonance of 85 Rb D1 transition with proper broadening and the corresponding coherent population trapping (CPT) resonance,with a signal contrast of 1.5% and linewidth of about 1.7 kHz,have been detected.The sealing quality and the stability of the cells have also been demonstrated experimentally by using the helium leaking detection and the after-9-month optoelectronics measurement which shows a similar CPT signal as its original status.In addition,the physics package of chip-scale atomic clock (CSAC) based on the cell was realized.The measured frequency stability of the physics package can reach to 2.1×10 10 at one second when the cell was heated to 100 C which proved that the cell has the quality to be used in portable and battery-operated devices.     

自旋1粒子在共振旋转磁场下的几何相

利用旋转坐标系方法求得了自旋为1粒子在共振旋转磁场下的波函数、自旋极化矢量,讨论了Rabi 振荡,并计算了系统的几何相、动力学相和总相位。