载入树状分子内部的纳米金修饰玻碳电极的制备及其对亚硝酸根的电化学测定

建立了一种简单、可靠的基于载入树状分子内部的纳米金修饰电极用于亚硝酸根测定的电化学分析方法.将壳聚糖(Chit)修饰在玻碳电极表面,在偶联活化剂碳二亚胺存在的条件下,4.5代羧基末端的树状分子(Dendrimer)通过其外围的羧基与壳聚糖的氨基形成酰胺键而连接在电极表面.Au(Ⅲ)通过与树状分子内部氮的配位作用被结合在...     

Revisit to frozen-in property of vorticity

Considering some simple topological properties of vorticity vector, the frozen-in property of vorticity herein is revisited. A vortex line, as is analogous to velocity vector along a streamline, is defined as such a coincident material(curve) line that connects many material fluid elements, on which the local vorticity vector for each fluid element is also tangent to the vortex line. The vortex line evolves in the same manner as the material line that it is initially associated with. The vortex line and the material line are both oriented to the same directions, and evolve with the proportional magnitude, just like being ‘frozen' or ‘glued' to the material elements of the fluid under the barotropic assumption. To relax the limits of incompressible and barotropic atmosphere, the frozen-in property is further derived and proved in the baroclinic case. Then two effective usages are given as examples. One is the derivation of potential vorticity conservation from the frozen-in property in both barotropic and baroclinic atmospheres, as a theory application, and the other is used to illuminate the vorticity generation and growth in ideal cases and real severe weather process, e.g., in squall line, tornado, and other severe convection weather with vortex. There is no necessity to derive vorticity equation, and this method is very intuitive to explain vorticity development qualitatively, especially for fast analysis for forecasters. Certainly, by investigating the evolution of vortex line, it is possible to locate the associated line element vector and its development on the basis of the frozen-in property of vorticity. Because it is simple and visualized, it manifests broad application prospects.     

Sn类钙钛矿太阳电池薄膜的掺杂改性研究

采用一步法分别制备了Sn类CH3NH3Sn I3和Pb类CH3NH3Pb I3钙钛矿太阳电池薄膜材料,并对其表面形貌、微观结构、吸收光谱和电池器件性能进行了表征和测试。研究结果表明:Sn类钙钛矿材料的吸收光谱相对于Pb类钙钛矿材料发生了明显的红移,吸收截止波长从800 nm上升到950 nm左右,光学带隙由1.45 e V降低至1.21 e V左右;Sn类钙钛矿材料的光谱吸收范围明显扩大,但吸收强度有所降低,相应太阳电池器件的光电转换效率也明显低于Pb类钙钛矿太阳电池,分别为2.05%和6.71%。而Br的掺杂可使Sn类钙钛矿材料带隙变宽,吸收光子能量增大,电池器件的开路电压也相应提高。当Br含量由0增加至完全替代I时,Sn类钙钛矿材料逐渐由黑褐色转变为黄色,光学带隙增大至1.95 e V,但吸收截止波长由950 nm降低至650nm。值得提及的是当Br含量为0.5时,电池器件的光电转换效率可由最初的2.05%提升至2.94%。     

五维自动调整差动共焦间隙测量方法

为精确、快速测量镜组内各透镜间的轴向间隙,提出一种基于五维自动调整的差动共焦间隙测量方法。该方法根据CCD探测器实时获取的光斑信号检测被测镜组光轴的平移偏差与倾斜偏差,依据偏差信息、通过五维自动调整技术实现镜组高精度调整,再利用差动共焦高精度层析定焦和镜组内部光线追迹实现轴向间隙高精度测量。分析和实验表明,本方法可以有效提高姿态调整效率3.4倍,透镜间隙重复测量精度可达到0.53μm。该方法为实现镜组间隙的快速高精度测量提供了有效途径,同时还为透镜的中心厚度、焦距、半径等多种参数快速高精度测量提供了有效方法。     

Hard Superconducting Gap in Pb Te Nanowires

<正>Semiconductor nanowires coupled to a superconductor provide a powerful testbed for quantum device physics such as Majorana zero modes and gate-tunable hybrid qubits. The performance of these quantum devices heavily relies on the quality of the induced superconducting gap. A hard gap,     

基于亲电/亲核反应描述符的气体介质绝缘强度预测

研究分子微观参数与气体介质绝缘强度的关联,可为SF₆替代气体筛选提供方向.本文基于密度泛函理论,采用M06-2X泛函与def2系列基组,计算了73种气体分子的亲电/亲核反应描述符,包括轨道能量参数、概念密度泛函理论的参数、不同电子概率密度等值面的静电势参数等;分析了各描述符与气体介质绝缘强度的相关性,以及描述符的独立性,最终提出了绝缘强度预测模型.最低空轨道能量、正负静电势表面积、静电势平均偏差、简缩局部亲电指数最小值与绝缘强度相关性较强,且彼此间相关性较低.预测模型在电子概率密度0.0002 a.u.时精度最优,其可决系数R²为0.809,均方误差MSE为0.096.     

Another look at the moist baroclinic Ertel–Rossby invariant with mass forcing

Due to the importance of the mass forcing induced by precipitation and condensation in moist processes, the Lagrangian continuity equation without a source/sink term utilized to prove the Ertel–Rossby invariant(ERI) and its conservation property is re-derived considering the mass forcing. By introducing moist enthalpy and moisture entropy, the baroclinic ERI could be adapted to moist flow. After another look at the moist ERI, it is deployed as the dot product between the generalized velocity and the generalized vorticity in moist flow, which constitutes a kind of generalized helicity.Thus, the baroclinic ERI is further extended to the moist case. Moreover, the derived moist ERI forumla remains formally consistent with the dry version, no matter whether mass forcing is present. By using the Weber transformation and the Lagrangian continuity equation with a source/sink effect, the conservation property of the baroclinic ERI in moist flow is revisited. The presence or absence of mass forcing in the Lagrangian continuity equation determines whether or not the baroclinic ERI in moist flow is materially conserved. In other words, it would be qualified as a quasi-invariant but only being dependent on the circumstances. By another look at the moist baroclinic ERI, it is surely a neat formalism with a simple physical explanation, and the usefulness of its anomaly in diagnosing atmospheric flow is demonstrated by case study.     

利用N粒子纠缠态的量子秘密共享

 为了高效实现多方之间的量子秘密共享,引入了一种纠缠度较高的N粒子纠缠态,并提出了利用该N粒子纠缠态在一方与（N-1）方之间形成共享秘密位串的方案.该方案在建立秘密位串的过程中,Alice对发送的粒子随机选择么正操作I和σx,并选择一部分粒子用于检测信道的安全|之后Alice根据（N-1）方选择的操作又选择了一部分粒子用于对参与者诚实度检测及信道安全检测.通过多次对窃听者的检测,很好地保证了信道的安全性及产生的秘密位串的可用性.最终在Alice及另外（N-1）方之间可形成n[1-(N-1)/2 N-1]/6个共享秘密位.     

FTIR研究快中子辐照直拉硅中的VO2

快中子辐照直拉硅(CZ-Si)经400-450℃热处理后，空位-双氧复合体(VO2)是其主要的缺陷．在300-500℃热处理快中子辐照的CZ-Si后，IR光谱中有919．6cm^-1和1006cm^-1两个吸收峰伴随VO2(889cm^-1)出现，这两个IR吸收峰是VO2的一种亚稳态缺陷(O-V-O)引起的，此缺陷态是由一个VO(A中心)与次临近的一个间隙氧原子(Oi)相互作用所形成的．在300℃延长退火时间或升高退火温度，都会使(O-V-O)转变为稳态VO2．辐照剂量在10^19数量级，经400-450℃热处理所形成的缺陷主要为多空位型，而VO2被抑制．     

FTIR研究快中子辐照直拉硅中的VO2

快中子辐照直拉硅(CZ-Si)经400—450℃热处理后，空位_双氧复合体(VO₂)是其 主要 的缺陷.在300—500℃热处理快中子辐照的CZ_Si后，IR光谱中有919．6cm^-1和 1006cm^-1两个吸收峰伴随VO₂(889cm^-1)出现，这两个IR吸收 峰是VO₂的一种亚稳态缺陷(O-V-O)引起的，此缺陷态是由一个VO(A中心)与次临近的一个 间隙氧原子(O_i)相互作用所形成的.在300℃延长退火时间或升高退火温度，都 会使(O -V-O)转变为稳态VO₂.辐照剂量在10¹⁹数量级，经400—450℃热处 理所形成的缺陷主要为多空位型，而VO₂被抑制.