多孔硅-导电聚酯材料复合发光器的光学特性研究

poly-4-dicyanomethylene-4H-cyclopenta[2,1-b:3,4-b]dithiophene monolayer(PCDM)是一种导电,低导带聚酯材料。如果在多孔硅纳米结构中附上一层以自组方式生成的PCDM单分子层,就可以制成能够产生稳定电致发光的器件。发光器的结构是金／PCDM／多孔硅／硅／铝,发光器的电致发光,在白天可用肉眼观察到。有很宽的发光波长,几乎覆盖了整个可见光区域且峰值位于650nm,发光器的面积为1cm^2,启动正向电压在14－30V,电流约300mA。经长时间测试,发光器的稳定性很好,在空气中放置3个月,在输入功率不变的情况下,发光强度也不发生变化,当施以反向电压时,样品仍可以发光而且稳定性较高,在250h内I－V未发生明显变化,扫描电镜图像显示PCDM覆盖的表面要比多孔硅表面平整,而PCDM分子有可能进入到多孔硅纳米孔径当中去,起到了提高发光器稳定性和延长其寿命的作用。     

Multi-Atom Entanglement Engineering in Distant Cavities via Resonant Interaction

We propose a scheme for the generation of entangled states for multiple atoms trapped in three distant cavities connected by two identical single-mode fibers. Compared with the previous schemes, the distinct advantages of the proposed scheme are： First, all the cavities in the proposed protocol can interact with each other freely, which is important in quantum communication and distributed quantum computation. Secondly, in the scheme, the atoms, cavities, and fiber mode are in resonance. Thus, the required interaction time is short, which is important in view of decoherence. In principle, the proposed scheme can be extended to generate n atoms entangled states.     

Research on Quantum Searching Algorithms Based on Phase Shifts

One iterative in Grover＇s original quantum search algorithm consists of two Hadamard-Walsh transformations, a selective amplitude inversion and a diffusion amplitude inversion. We concentrate on the relation among the probability of success of the algorithm, the phase shifts, the number of target items and the number of iterations via replacing the two amplitude inversions by phase shifts of an arbitrary φ = ψ（0 ≤, ψ≤ 27r）. Then, according to the relation we find out the optimal phase shifts when the number of iterations is given. We present a new quantum search algorithm based on the optimal phase shifts of 1.018 after 0.57π√M/N iterations. The new algorithm can obtain either a single target item or multiple target items in the search space with the probability of success at least 93.43%     

基于磁开关的全固态、高功率、长脉冲发生器的初步研究

大多数电容储能型脉冲功率装置的共同特点是采用了气体开关, 由于气体绝缘恢复的限制和电极的烧蚀, 使得其重复频率都不太高, 而且寿命有限. 而目前广泛研究的磁脉冲压缩技术在脉冲功率系统的长寿命、高平均功率和高重复频率运行方面具有很大的应用前景. 通过对BOOST电路、LC谐振电路和磁脉冲压缩电路详细的理论分析和计算机模拟, 设计了由BOOST电路, LC谐振电路, 脉冲变压器, 磁压缩系统, 负载五大部分组成的脉冲发生器电路系统模型, 使用Pspice软件对系统进行了模拟、优化, 得到了电压幅值为55kV, 脉宽为500ns的输出脉冲.     

基于磁开关的全固态、高功率、长脉冲发生器的初步研究

大多数电容储能型脉冲功率装置的共同特点是采用了气体开关,由于气体绝缘恢复的限制和电极的烧蚀,使得其重复频率都不太高,而且寿命有限.而目前广泛研究的磁脉冲压缩技术在脉冲功率系统的长寿命、高平均功率和高重复频率运行方面具有很大的应用前景.通过对BOOST电路、LC谐振电路和磁脉冲压缩电路详细的理论分析和计算机模拟,设计了由B00ST电路,C谐振电路,脉冲变压器,磁压缩系统,负载五大部分组成的脉冲发生器电路系统模型,使用Pspice软件对系统进行了模拟、优化,得到了电压幅值为55kV,脉宽为500ns的输出脉冲.     

Spin gapless armchair graphene nanoribbons under magnetic field and uniaxial strain

Using Green＇s function method, we investigate the spin transport properties of armchair graphene nanoribbons （AG- NRs） under magnetic field and uniaxial strain. Our results show that it is very difficult to transform narrow AGNRs directly from semiconductor to spin gapless semiconductors （SGS） by applying magnetic fields. However, as a uniaxial strain is exerted on the nanoribbons, the AGNRs can transform to SGS by a small magnetic field. The combination mode be- tween magnetic field and uniaxial strain displays a nonmonotonic arch-pattern relationship. In addition, we find that the combination mode is associated with the widths of nanoribbons, which exhibits group behaviors.     

A Ubiquitous Thermal Conductivity Formula for Liquids,Polymer Glass,and Amorphous Solids

The microscopic mechanism of thermal transport in liquids and amorphous solids has been an outstanding problem for a long time.There have been several approaches to explain the thermal conductivities in these systems, for example, Bridgman’s formula for simple liquids, the concept of the minimum thermal conductivity for amorphous solids, and the thermal resistance network model for amorphous polymers.Here, we present a ubiquitous formula to calculate the thermal conductivities of liquids and amo...     

二甲基亚砜-水混合溶液的等效介电常数特异性研究

在2.45 GHz下利用微扰谐振腔法测量二甲基亚砜(DMSO)-水(H₂O)混合溶液的等效介电常数过程中, 发现混合溶液等效介电常数虚部大于其中任一组分的介电常数虚部的特异现象. 分析表明, 这种特异性现象的发生主要是由于DMSO与H₂O混合后溶液的高频摩擦项大于混合前引起的. 因此, 经典混合物介电常数公式需要进行适当修正才能较好地适用于这类特异性问题计算.     

杂多酸催化研究新进展

杂多酸催化剂泛指杂多酸及其盐 ,是一类由中心原子 (即杂原子 ,如 P、 Si等 )和配位原子 (即多原子 ,如 Mo、 W等 )通过氧原子桥联方式进行空间组合的多氧簇金属配合物 (polyoxometalate) ,作为催化材料广泛应用于均相与多相催化反应体系 .近年来 ,杂多酸在催化领域中受到越来越多关注 ,主要原因是 :1 .随着石油化工与精细化工的发展 ,催化材料的多功能性成为研究的新目标 .杂多酸是一种酸碱性与氧化还原性兼具的双功能型催化剂 ,对于新催化过程的研究具有重要意义 ;2 .随着分子“剪裁”技术的迅速兴起 ,新型催化材料层出不穷 .杂多酸的阴…     

EXAFS研究Ni-B和Ni-Ce-B超细非晶态合金的退火晶化

采用同步辐射EXAFS技术定量地研究化学还原法制备的Ni-B和Ni-Ce-B超细非晶态合金中Ni原子的局域环境结构随退火温度升高而产生的变化,结果表明,对于Ni-B和Ni-Ce-B超细非晶态合金初始样品：Ni-Ni最邻近配位壳层的平均键长RNi-Ni、配位数N、热无序σT、结构无序σs分别为0．275nm,11.9.0.0069nm,0.034nm;0.276nm,12.4,0.0067nm,0.035nm,Ni-B最邻近配位壳层的RNi-B,N, σT,σs分别为0．215nm,2.7,0.0055nm,0.0048nm;0.214nm,2.0,0.0058nm,0.0042nm,Ni-Ni配位的σs很大,是其σT的4－5倍,比Ni－B配位的σs大近一个数量级,在300℃退火后,Ni－B样品开始发生晶化生成晶态Ni3B,其RNi-Ni和σs分别为0．254nm和0．011nm,σs降低近2倍;而．3％原子比的Ce掺入后使Ni-Ce-B超细非晶态合金的晶化温度升高100℃左右。在500℃退火后,Ni－B样品的结构参数与Ni箔的相近,但Ni-Ce-B样品中的Ni-Ni配位的σs仍为0．0073nm,Ni-B配位的N为1．2,表明稀土元素Ce（以CeO2)显著增强了Ni与B的相互作用,且同时使退火晶化成的Ni晶结构产生畸变。