3,6-二苯氧甲基-1,2,4-三唑并[3,4-b]- 1,3,4-噻二唑衍生物的合成及生物活性

以4-氨基-5-苯氧甲基-3-巯基-1,2,4-三唑与取代苯氧乙酸为原料,三氯氧磷为溶剂,回流反应, 合成了3,6-二苯氧甲基-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑衍生物。通过IR、1H NMR和元素分析确定了各化合物分子结构,并对其进行了室内毒力测试,结果表明此类化合物具有较好的杀菌、抑菌活性。     

Evolution Mechanism of Calcium Carbonate in Solution

Calcium carbonate was synthesized in a CaCl₂/NaCO₃ mixed solution by using ethylenedi-aminetetraacetic acid (EDTA) as an additive. The thermodynamics and kinetics analyses indicate that although the driving force of amorphous calcium carbonate (ACC) precipi-tation is always less than that of calcite and vaterite precipitation, the nucleation rate of ACC is greater than that of calcite and vaterite at the initial stage of the precipitation reaction. With the increasing incubation time, vaterite and calcite particles nucleate het-erogeneously by using the as-formed particles as active sites. Scanning electron microscopyimages indicate that the transformation mechanism of ACC and vaterite to calcite is the dissolution-recrystallisation reaction. The presence of EDTA not only improves the stabil-ities of ACC and vaterite, but also leads to forming enlongated, connected rhombohedralcalcite crystals after incubation 7 days in solutions. The ACC and vaterite are stabler in air than in solutions at room temperature, although the dissolution-recrystallisation reaction occurs on the surface.     

W-State Generation and Manipulation for Ion-Trap-Based Quantum-Information Processing

We propose an ion-trap scheme for one-step generation of a special configuration of W-class state which has recently been shown to be better than canonical W states for several quantum-information processing tasks. We also present a method for one-step realization of a nontrivial collective operation which can transform a canonical W state into a fully separable state. Such a transformation plays a key role in recently proposed quantum protocols. The operation speed in our schemes increases with the number of qubits. This is contrary to usual entanglement generation and quantum manipulation schemes which take more and more time with the increase of the number of qubits.     

一个高效的基于身份的群密钥协商协议

群密钥协商协议是在Ad Hoc网络群通信中建立会话密钥的一种有效解决方法.但由于Ad Hoc网络是一个拓扑结构变化频繁的网络,因而在群通信中,不仅要建立一致的会话密钥,还要考虑成员变化的情况.文中结合完全二又树结构,提出了一种新的基于身份的群密钥协商协议.新方案具有隐含密钥认证、已知会话密钥安全,前向安全、抗密钥泄露攻击.抗未知密钥共享攻击、密钥控制等安全特性,并且效率较高.     

便携应用DC-DC轻负载高效率的实现

提出了一种新颖的DC-DC环路控制结构.轻负载时芯片自动进入省电模式,通过检测反馈电压使其在待机状态与固定峰值状态切换工作,平均静态功耗以及开关功耗大大减小,提高了轻负载效率,延长了便携应用电池的使用时间.内部同步整流消除了肖特基二极管的使用,进一步提高了效率.该结构在一款0.5μm CMOS工艺的降压型DC-DC中进行了投片验证.输入电压3.6V,输出电压1.8V条件下,待机状态静态电流仅为25μA,0.1mA负载下效率高达62%.最高效率为96%.     

伪随机码激光引信探测系统设计

半导体激光器件的激光近炸引信在各种导弹和常规弹药中已得到了广泛的应用。设计了基于伪随机码脉冲激光引信的实现方法,根据其工作原理,整个系统可分为发射模块、接收模块、光学系统和信号处理模块。对伪码激光引信各模块的具体构成进行了详细分析,得出了选择各模块参数的依据。结果表明,伪码激光引信能够满足战技指标要求,且具有较强的探测和抗干扰性能。该设计方法对伪码激光引信的研制具有一定的指导意义。     

背景散射对LRCS测量精度的影响分析

针对激光雷达散射截面的测量精度,指出测量中存在的背景散射问题。给出了激光雷达散射截面的测量方程,分析了地面、支撑架等背景散射对激光雷达散射截面测量精度影响的机理。根据测量方程和影响机理提出了敷设消光材料、多次比对测量、尺寸匹配等方法,并对敷设消光材料法进行了实验验证。实验表明：所用方法能够有效地减小背景散射,提高激光雷达散射截面的测量精度。     

Improvement of Plasticity of Ti-Based Bulk Metallic Glasses by Addition of Nb

Ti-based bulk metallic glasses （Ti40Zr25Cu9NisBe18 ）100-x Nbx with x = 0 to 5 at. % are prepared by copper-mold casting. The glass formation ability is almost unchanged by addition of Nb. The compression plasticity is, however, apparently changed, from 3% at x = 0 to 13% at x = 3, about 330% increases at the strain rate of 1 × 10^-4 8^-1. The increment of the plasticity can be attributed to the segregation of Nb in the area of shear bands during the compression processing. An effective way to increase the plasticity of Ti-based bulk metallic glasses is thus proposed.     

震后九年级初期阶段学生学习化学现状的调查分析

旌阳区是"5.12"大地震中的重灾区,作为大地震后起始学科的九年级化学,在初期学习阶段,学生学习的态度如何,具备了学习化学的哪些能力,在其他学科的学习中已经养成的学习习惯和学习方法对化学学习有什么的影响,在课堂内外他们是如何完成学习任务的,在学习中存在的主要问题和困难是什么.     

溶胶-凝胶、微波加热合成Li1.3Al0.3Ti1.7(PO4)3粉体

以钛酸丁酯、硝酸锂、硝酸铝和磷酸为原料,采用溶胶-凝胶、微波加热的工艺合成了Li1.3Al0.3Ti1.7(PO4)3粉体,并研究了热处理温度对粉体结构的影响.用X射线衍射仪(XRD)、傅立叶变换红外光谱仪(FT-IR)、扫描电镜(SEM)对制备的粉体进行了表征.结果表明:溶胶凝胶、微波加热工艺与固相合成工艺相比可以显著地降低热处理的温度,缩短保温时间;前躯体经700~900 ℃微波热处理30 min后均可合成纯相的Li1.3Al0.3Ti1.7(PO4)3粉体,且结晶性良好,粉体的粒度为2~5 μm.