非晶/结晶共混对聚合物光伏电池性能的影响

以局域规整聚（3-己基噻吩） （P3HT）制备了TiO₂/聚合物型双层结构光伏电池.利用稳态电流-电压测试和动态强度调制光电压谱,结合差热分析、吸收光谱和荧光光谱, 研究了非晶支化聚亚乙基亚胺（BPEI）作为P3HT膜层的添加成分对TiO₂/P3HT双层电池性能的影响.由于P3HT链的高结晶性,使得TiO₂/P3HT界面接触不好,导致电池性能差.当在P3HT中共混重量比W_BPEI/P3HT=1％—5％的BPEI时,电池性能得到显著改善;尤其是当W_BPEI/P3HT= 1％时,电池表现出近0.8V的开路电压和20μA/cm²的短路电流.结果表明BPEI对电池性能的影响不是源于P3HT-BPEI共混体系光学性能的变化,而主要是由于其改变了TiO₂/P3HT界面接触性能.BPEI对TiO₂/P3HT界面接触有两个相互竞争的影响,这取决于P3HT-BPEI共混体系的组成.一方面,通过降低P3HT的结晶度和增强与TiO₂表面的相互作用,改善P3HT链在TiO₂ 表面的附着;另一方面,当BPEI含量过高时,BPEI在TiO₂表面的附着量将增加,反而会阻碍P3HT与TiO₂表面的接触.良好的TiO₂/P3HT界面接触有利于提高激子的界面分离效率、光生电子的寿命和电池效率.本文结果有望为聚合物光伏电池性能的改善提供新的认识和方法. 关键词： 聚（3-己基噻吩） 二氧化钛 共轭聚合物 光伏电池     

Alq3和CdSeS量子点掺杂体系的载流子输运性质的研究

利用飞行时间法(time-of-flight)测定了有机小分子发光材料8-羟基喹啉铝(Alq3)与CdseS量子点掺杂体系的载流子迁移率.研究了Alq3和CdSeS混合薄膜的载流子迁移率与外加电场强度和量子点浓度的变化关系.研究结果表明,CdSeS量子点的掺杂浓度的增加会引起薄膜样品位置无序的增加.除此之外,Alq3和CdSeS量子点界面之间的电荷转移作用,以及在量子点之间进行跳跃传输的电子数量都会改变样品的载流子迁移率.     

基于超声红外技术对金属管内壁缺陷的检测

为提高管道的运送效率,及时检测排除管道内壁的缺陷非常重要。提出利用超声红外无损检测方法对管道内部进行检测。超声主动热激励试件,高频红外热像仪记录试件表面温度变化,结合了超声摩擦生热和红外热成像的优点。对壁厚约为3.3mm检测难度较大的金属管内壁缺陷进行了检测。通过对采集数据和热图的处理分析,准确快速地确定缺陷所在的位置。实物对比分析表明：超声热激励红外无损检测技术可以对金属管道内壁缺陷进行准确检测定位。     

Security of continuous-variable measurement-device-independent quantum key distribution with imperfect state preparation

The state preparation operation of continuous-variable measurement-device-independent quantum key distribution (CV-MDI-QKD) protocol may become imperfect in practical applications. We address the security of the CV-MDI-QKD protocol based on imperfect preparation of the coherent state under realistic conditions of lossy and noisy quantum channel. Specifically, we assume that the imperfection of Alice's and Bob's practical state preparations equal to the amplification of ideal modulators and lasers at both Alice's and Bob's sides by untrusted third-parties Fred and Gray employing phase-insensitive amplifiers (PIAs), respectively. The equivalent excess noise introduced by the imperfect state preparation is comprehensively and quantitatively calculated by adopting the gains of PIAs. Security analysis shows that CV-MDI-QKD is quite sensitive to the imperfection of practical state preparation, which inevitably deteriorates the performance and security of CV-MDI-QKD system. Moreover, a lower bound of the secret key rate is derived under arbitrary collective attacks, and the upper threshold of this imperfection tolerated by the system is obtained in the form of the specific gains of PIAs. In addition, the methods presented will improve and perfect the practical security of CV-MDI-QKD protocol.     

The Improvement of Performance for Continuous-Variable Quantum Key Distribution with Imperfect Gaussian Modulation

Gaussian modulation is one of the key steps for the implementation of continuous-variable quantum key distribution (CVQKD) schemes. However, imperfection in the Gaussian modulation may introduce modulation noise that can deteriorate the performance of CVQKD systems. In this paper, we mainly investigate how to improve the performance of a CVQKD system from different aspects. First, we explore the several different origins, impacts and monitoring schemes for the modulation noise in detail. Then, we discuss the practical performance of a CVQKD system with an untrusted noise model and neutral party model, respectively. These analyses indicate that the neutral party model should be reasonably regarded as a general noise model, which will passively and greatly raise the performance of the system. Further, we propose a dynamic auto-bias control scheme to actively resist the modulation noise which comes from the drift of bias point of the amplitude modulator. Together these methods contribute to the improvement of the practical performance of CVQKD systems with imperfect Gaussian modulation.

     

人工构建二维准晶复合结构的减阻特性研究

采用旋转锥板式剪切力测试系统,测试了人工构建的具有五次、八次、十次、十二次对称性的二维准晶结构对甘油和水混合液的减阻性能,并与随机排列结构和周期排列结构的流阻进行了对比.对比试验发现：准晶结构具有显著的减阻效果,其中具有十二次对称性的二维准晶结构减阻效应最大,在剪切率为200—2000 s^-1时,剪切力减小的幅度从15%—9%,其最大减阻量可达到15.4%.进一步在所构建的大尺度二维准晶结构的表面,再复合制备微/纳米粗糙结构,这两种尺度的结构协和作用,可实现减阻效果明显提高. 关键词： 准晶结构 粗糙结构 十二次对称性 减阻     

熔体旋甩工艺对Zn掺杂Ⅰ-型Ba8Ga12Zn2Ge32笼合物微结构及热电性能的影响

采用新颖的熔体旋甩(MS)结合放电等离子烧结(SPS)技术制备了单相Zn掺杂的Ⅰ-型Ba₈Ga₁₂Zn₂Ge₃₂笼合物,研究了熔体旋甩工艺对其微结构以及热电性能的影响. 结果表明,MS得到的薄带自由面主要由300nm—1μm的小立方体单晶组成,薄带经SPS烧结后得到了具有大量层状精细结构的致密块体. 与熔融+SPS工艺制备的试样相比,熔融+MS+SPS制备的Ba₈Ga₁₂Zn 关键词： 熔体旋甩 Ⅰ-型笼合物 热电性能     

Simulation study on terahertz vibrational absorption in liquid crystal compounds

The terahertz (THz) spectrum absorptions of nematic liquid crystal (LC) material, i.e. N-(p-methoxybenzylidene)-p-butylaniline (MBBA), and its relevant compounds are simulated in this paper by using the density functional theory (DFT) method. A strong absorptive frequency is located at 3.65 THz for the MBBA, which is in agreement with experimental data found in the literature. The result suggests that the DFT method is effective for dealing with the anisotropic nematic LC compounds.     

Long-distance quantum teleportation assisted with free-space entanglement distribution

Faithful long-distance quantum teleportation necessitates prior entanglement distribution between two communicated locations. The particle carrying on the unknown quantum information is then combined with one particle of the entangled states for Bell-state measurements, which leads to a transfer of the original quantum information onto the other particle of the entangled states. However in most of the implemented teleportation experiments nowadays, the Bell-state measurements are performed even before successful distribution of entanglement. This leads to an instant collapse of the quantum state for the transmitted particle, which is actually a single-particle transmission thereafter. Thus the true distance for quantum teleportation is, in fact, only in a level of meters. In the present experiment we design a novel scheme which has overcome this limit by utilizing fiber as quantum memory. A complete quantum teleportation is achieved upon successful entanglement distribution over 967 meters in public free space. Active feed-forward control techniques are developed for real-time transfer of quantum information. The overall experimental fidelities for teleported states are better than 89.6%, which signify high-quality teleportation.