含1,2,4-三唑-5-硫酮席夫碱的新型1,2,4-三唑并[1,5-a]嘧啶衍生物的合成及生物活性研究

以2-苄硫基-5-甲基-7-羟基-1,2,4-三唑并[1,5-a]嘧啶为原料,经醚化、肼解、成盐、关环和席夫碱反应合成了20个新型的含1,2,4-三唑-5-硫酮席夫碱的1,2,4-三唑并[1,5-a]嘧啶类化合物,通过IR,1H NMR,MS和元素分析对所合成的化合物进行了结构表征.初步生物活性测试结果表明,部分化合物表现出一定的抑菌或较好的抗烟草花叶病毒(TMV)活性.在500μg/mL浓度下,化合物6b,6f和6p对TMV的抑制率分别为41%,43%和40%.     

左手介质椭圆光波导基模传播特性

在椭圆柱坐标系中,采用分离变量方法,得出了左手介质椭圆光波导本征方程的近似解,通过数值计算,分析了椭圆波导偏心率、左手介质的电容率、磁导率对椭圆光波导基模传播特性的影响,并将左介质光波导与右手介质光波导基模特性进行对比,得出左手介质光波导的基模特性与右手介质光波导基模特性差别不大的结论.     

140GHz大功率交错双栅行波管的设计和模拟研究

采用交错双栅结构,结合带状电子注,研究了一种工作在140 GHz频段的大功率行波管. 本振模数值计算表明该结构具有良好的色散特性和耦合阻抗.针对所采用的慢波结构, 提出了慢波过渡结构、输入输出耦合器和集中衰减器,保证了行波管的良好工作. 利用三维大信号模拟计算的方法得到的结果显示,当电子注直流功率为5.115 kW,输入信号功率为0.1 W时, 所研究的行波管能在132-152 GHz范围内提供大于300 W的峰值功率,其中在138 GHz时得到最大功率546 W, 对应增益为37.37 dB.当在0.027-0.46 W内调节输入信号功率,可以保持该行波管在128-152 GHz 频带内得到大于440 W的峰值功率,对应的电子效率大于8.6%. 结果显示该行波管将在大功率短毫米波领域具有重要意义和潜在应用价值.     

Control of reaction channels of CsI molecule by ultra-short laser pulse

The influence of the ultra-short pulse wavelength on the populations in the three electronic states of CsI molecule is investigated using the time-dependent wave packet method. The calculated results show that the populations in the two excited states approach to the maxima at the wavelengths of 369 nm and 297 nm, respectively. The photodissociation reaction channels of the CsI molecule can be chosen by controlling the pump pulse wavelength.     

Effect of high magnetic field annealing on the microstructure and magnetic properties of Co-Fe layered double hydroxide

The effects of high magnetic field (10 T) on the products obtained by calcination of Co-Fe LDH precursors at different temperatures were investigated. The XRD results indicated that Fe^III substituted for Co^III in Co₃O₄ to yield Co^IICo^IIIFe^IIIO₄ under the calcination of Co-Fe LDH precursors at 400 °C. The products obtained by magnetic field annealing at 400 °C had a porous plate-like morphology, whereas the products without magnetic field annealing were composed of nanoparticles. It was seen that CoFe₂O₄ phase could be formed at low temperature (about 500 °C) under the magnetic field annealing. The grain size of products obtained by magnetic field annealing at 800 °C was larger than that of zero magnetic field. It was found that the saturation magnetization was significantly enhanced after magnetic field annealing, especially at lower temperature (≤600 °C). The possible reason for the effects on the microstructure and magnetic properties of products obtained by magnetic field annealing was discussed.     

高效强流径向分离腔振荡器研究

根据同轴虚阴极的结构特点,提出了一种紧凑型径向分离腔振荡器,该径向分离腔的特点是输入电子束的电流可以很大,从而可以得到较高的微波输出功率. 综合考虑影响微波输出的各种因素,在电子束为410kV,电流为35kA的条件下,模拟得到的平均功率大于50GW,频率为146GHz,电子束功率效率达到348%. 关键词： 径向分离腔 高功率微波 同轴虚阴极 电子束分布     

Structural transition behavior of ZnS nanotetrapods under high pressure

ZnS nanotetrapods synthesized via a solvothermal route have a octahedral core with a zincblende (ZB) structure and four hexprism-shaped arms consisting of alternately stacking ZB and wurtzite (WZ) phases, where the WZ phase has a higher volume percentage. In situ angular-dispersive X-ray diffraction (ADXRD) measurements were carried out to study the structural behavior of ZnS nanotetrapods under high pressure up to 41.3?GPa. The initial WZ structure exhibits a very high mechanical stability to ～11.3?GPa. Both the WZ and ZB structures transform to the rocksalt (RS) structure at ～15.4?GPa. The bulk moduli of the WZ (148.2?±?8.9?GPa) and RS (165.6?±?9.9?GPa) phases are both larger than the previously reported values. These phenomena are discussed based on the alternating epitaxial growth of the WZ and ZB phases in the arms of nanotetrapods. Our study suggests that the internal structure of nanomaterials could also greatly affect their stability and transition behavior.     

The bound of entanglement of superpositions with more than two components

A bipartite quantum state (for two systems in any dimensions) can be decomposed as a superposition of many components. For a superposition of more than two components we prove that there is a bound of the entanglement of the superposition state which can be expressed according to entanglements of its component states. Especially, if the component states are mutually bi-orthogonal, the entanglement of the superposition state can be exactly given in terms of the entanglements of the states being superposed.     

针孔辅助点投影诊断方法实验研究

针孔辅助点投影背光成像是近几年国外新兴的等离子体诊断技术,在惯性约束聚变相关物理实验诊断中具有重要的应用前景.为验证这一诊断方法的实用性,在神光Ⅱ第九路平台上开展了演示实验.利用激光驱动平面Ti靶获得约4.7 keV的Ti K壳层X射线,在十几微米的针孔约束下作为次级点源并对Au栅格样品投影成像,并用CCD记录.实验成功获得了清晰的样品二维空间分辨的时间积分图像,空间分辨力优于16.1 μm.实验结果表明针孔辅助点投影具有较高的空间分辨力、较大的视场、较高的图像对比度,将成为瑞利泰勒不稳定性研究、激光状态方程研究等物理实验的重要诊断方法之一.     

奇异介子光生反应的QCD描述

从低能QCD有效拉氏量出发,利用重子夸克结构的[SU_SF(6)⊙O(3)]_sym.⊙SU_c(3)波函数,研究了在核子上的奇异介子光生反应.计算了γ+p→K⁺+Λ反应的微分截面.结果表明:与传统唯象的强子理论相比,仅有一个自由参数(即强相互作用耦合常数)的QCD理论成功地描述了反应过程,很好地解释了实验结果.