S—Ka频段电磁波在等离子体中传输特性的实验研究

在感应耦合等离子体风洞上开展了等离子体中电磁波传输特性实验研究,获得了不同频率电磁波在等离子体中的传输衰减.通过微波诊断技术,获得了等离子体射流的电子数密度和碰撞频率.通过矢量网络分析仪和标准增益天线组成的电磁波传输特性测试系统,获得了电磁波经过等离子体之后的衰减,研究了电子数密度范围7.0×10~(10)-1.0×10~(13)cm~(-3)、等离子体碰撞频率在109 Hz量级的等离子体对2.6—40 GHz不同频率电磁波传输特性的影响,分析了经典传输理论和薄层理论预测结果与实验结果的差异.该实验工作为等离子体中电磁波传输特性的理论研究和数值仿真提供了基础数据.     

可降解聚合物包覆次血红素六肽微球的制备及生物活性

采用水包油包水(W₁/O/W₂)复乳溶剂挥发法制备了包覆次血红素六肽(DhHP-6)的2种聚酯微球. 通过扫描电子显微镜、 体外缓释行为、 高效液相(HPLC)检测、 酶活力测定和初步的动物实验等表征, 综合评价了载药微球的体外释放及体内生物活性. 实验结果表明, 载药微球球体圆整, 粒径分布均匀, 载药量高, 能够实现体外缓释, 并对细胞过氧化损伤和小鼠脑缺血损伤均有一定的保护作用.     

First-Principles Calculations on Electronic,Chemical Bonding and Optical Properties of Cubic Hf_3N_4

Electronic,chemical bonding and optical properties of cubic Hf 3N4(c-Hf3N4) are calculated using the firstprinciples based on the density functional theory(DFT).The optimized lattice parameter is in good agreement with the available experimental and calculational values.Band structure shows that c-Hf3N4 has direct band gap.Densities of states(DOS) and charge densities indicate that the bonding between Hf and N is ionic.The optical properties including complex dielectric function,refractive index,extinction coefficient,absorption coefficient,and reflectivity are predicted.From the theory of crystal-field and molecular-orbital bonding,the optical transitions of c-Hf3N4 affected by the electronic structure and molecular orbital are studied.It is found that the absorptive transitions of c-Hf3N4 compound are predominantly composed of the transitions from NT22p valence bands to HfT2(dxy,dxz,dyz) conduction bands.     

First-Principles Calculations of Structural,Elastic and ElectronicProperties of Tetragonal HfO2under Pressure

Structural, elastic and electronic properties of tetragonal HfO₂ at applied hydrostatic pressure up to 50 GPa have been investigated using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT). The calculated ground-state properties are in good agreement with previous theoretical and experimental data. Six independent elastic constants of tetragonal HfO₂ have been calculated at zero pressure and high pressure. From the obtained elastic constants, the bulk, shear and Young's modulus, Poisson's coefficients, acoustic velocity and Debye temperature have been calculated at the applied pressure. Band structure shows that tetragonal HfO₂ is an indirect band gap. The variation of the gap versus pressure is well fitted to a quadratic function.     

Two-dimensional multiplicity fluctuation analysis of target residues in nuclear collisions

Multiplicity fluctuation of the target residues emitted in the interactions in a wide range of projectile energies from 500 A MeV to 60 A GeV is investigated in the framework of two-dimensional scaled factorial moment methodology.The evidence of non-statistical multiplicity fluctuation is found in 16 O-AgBr collisions at 60 A GeV,but not in 56 Fe-AgBr collisions at 500 A MeV,84 Kr-AgBr collisions at 1.7 A GeV,16 O-AgBr collisions at 3.7 A GeV and 197 Au-AgBr collisions at 10.7 A GeV.     

掺杂As2S8非晶态薄膜波导的光阻断效应

实验研究了未掺杂和低浓度掺锡和掺磷的As₂S₈薄膜波导的光阻断效应,提供了三种样品的光阻断响应曲线、室温退激实验数据和光谱测试数据. 结果表明,掺锡样品可以明显提升毫秒级响应的快过程恢复作用,同时还具有减少残留传输损耗的效果,掺磷的效果则相反. 结合实验结果给出了分析讨论. 关键词： 光波导技术 硫属化合物玻璃 光阻断效应 掺杂     

基于透射光谱确定溶胶凝胶ZrO2薄膜的光学常数

基于溶胶凝胶ZrO2薄膜的紫外/可见/近红外透射实验光谱,采用Swanepoel方法结合Wemple-DiDomenico色散模型,方便地导出了ZrO2薄膜在200-1200 nm波长范围内的光学常数,包括折射率、色散常数、膜层厚度、吸收系数及能量带隙.研究发现,溶胶凝胶ZrO2薄膜具有高折射率(1.63-1.93,测试波长为632.8 nm)、低吸收和直接能量带隙(4.97-5.63 eV) 等光学特性,而且其光学常数对薄膜制备过程中的重要工艺参数--膜层后处理温度表现出强烈的依赖性.此外,在膜层的弱吸收和中等吸收光谱区域内,计算得到的折射率色散曲线与分光光度法的测试结果基本符合,说明本实验中所建立的计算方法在确定溶胶凝胶ZrO2薄膜光学常数方面的可靠性.     

疏水/亲水性聚二乙烯基苯/聚丙烯酸大孔互穿聚合物网络树脂对苯胺的吸附性能

采用分步悬浮聚合法制备了聚二乙烯基苯/聚丙烯酸甲酯（PDVB/PMA）大孔互穿聚合物网络,将其中的聚丙烯酸甲酯转化为聚丙烯酸,得到具有疏水/亲水性能的聚二乙烯基苯/聚丙烯酸（PDVB/PAA）大孔互穿聚合物网络（IPN）,研究了这类疏水/亲水大孔PDVB/PAA IPN对苯胺的吸附热力学和吸附动力学,测定了该树脂的孔结构、含水量、弱酸交换量和溶胀性能;测定了该树脂对苯胺在不同温度下的吸附等温线,利用热力学函数关系计算了吸附焓、自由能和熵。 红外光谱显示,成功合成了疏水/亲水PDVB/PAA IPN,与PDVB、PDVB/PMA IPN树脂相比,其BET表面积以及孔容均减小,含水量为62.73％,弱酸交换量为1.91 mmol/g;对苯胺的吸附为放热、自发的过程;溶胀实验、静态解吸实验表明,PDVB/PAA IPN树脂中疏水性的PDVB网具有疏水作用吸附能力,亲水性的PAA网具有氢键作用吸附能力。 对苯胺的吸附在90 min时即可达到吸附平衡,树脂吸附苯胺符合一级速率方程,吸附速率主要受颗粒内扩散的控制,同时还受液膜扩散的影响,吸附动力学可采用HSDM模型描述。     

一种CdⅡ-MOF作为传感Fe(Ⅲ)和Cr(Ⅵ)的多响应荧光探针

通过水热法合成了一种金属有机骨架[Cd₃(L)₂(H₂O)₉]·9H₂O (MOF 1),其中H₃L=5-(((4-羧基苯基)氧基)甲基)苯-1,3-二甲酸,并通过单晶X射线衍射、粉末X射线衍射和元素分析对其进行了表征。MOF 1表现为一个二维微孔结构,孔隙可利用体积为22.4%。荧光性能研究表明,MOF 1可以用作检测Fe(Ⅲ)和Cr(Ⅵ)的荧光传感器。它具有高选择性和低检测限,而且不受其他离子的干扰。此外,通过金属有机骨架主体和目标分析物客体的紫外可见吸收光谱研究了主体配合物的选择性荧光猝灭机制。这种荧光猝灭的可能机制是荧光共振能量转移。     

Partial evolution based local adiabatic quantum search

Recently, Zhang and Lu provided a quantum search algorithm based on partial adiabatic evolution, which beats the time bound of local adiabatic search when the number of marked items in the unsorted database is larger than one. Later, they found that the above two adiabatic search algorithms had the same time complexity when there is only one marked item in the database. In the present paper, following the idea of Roland and Cerf [Roland J and Cerf N J 2002 Phys. Rev. A 65 042308], if within the small symmetric evolution interval defined by Zhang et al., a local adiabatic evolution is performed instead of the original “global” one, this “new” algorithm exhibits slightly better performance, although they are progressively equivalent with M increasing. In addition, the proof of the optimality for this partial evolution based local adiabatic search when M=1 is also presented. Two other special cases of the adiabatic algorithm obtained by appropriately tuning the evolution interval of partial adiabatic evolution based quantum search, which are found to have the same phenomenon above, are also discussed.