Delayed Fluorescence Emitter Enables Near 17% Efficiency Ternary Organic Solar Cells with Enhanced Storage Stability and Reduced Recombination Energy Loss

Charge transfer state (CT) plays an important role in exciton diffusion, dissociation, and charge recombination mechanisms. Enhancing the utilization and suppressing the recombination process of CT excitons is a promising way to improve the performance of organic solar cells (OSCs). Here, an effective method is presented via introducing a delayed fluorescence (DF) emitter 3,4‐bis(4‐(diphenylamino)phenyl)acenaphtho[1,2‐b]pyrazine‐8,9‐dicarbonitrile (APDC‐TPDA) in OSCs. The long‐lifetime singlet excitons on APDC‐TPDA can transfer to polymer donors to prolong exciton lifetime, which ensures sufficient time for diffusion and dissociation. Concurrently, the high triplet energy level (T₁) of the DF material can also prevent the reverse energy transfer from CT to T₁. APDC‐TPDA‐containing ternary OSCs shows a high PCE of 16.96% with a reduced recombination energy loss of 0.46 eV. It is noteworthy that the ternary OSC also exhibits superior storage stability. After 55 days of storage, the PCE of the ternary OSC still retains about 96% of its primitive state. Furthermore, this ternary strategy is efficient and universally applicable to OSCs, and positive results can be obtained in different systems with different DF emitters. These results indicate that the ternary strategy provides a new design idea to realize high performance OSCs.     

软交换网络监控模型的设计与应用

随着以软交换为核心的下一代网络的发展,如何在软交换网络中实现监听和控制成为了热点问题.文章重点研究了软交换网络自身的特性,分析了现有的软交换网络监听接口规范存在的不足之处,给出了一种可以同时实现对网络监听和接续控制的软交换网络监控模型设计方案.文章最后以SIP(会话初始协议)网络为例对该方案的应用进行了描述,并对监控的流程进行了具体的说明.     

Voice over wireless local area network

This paper introduces the special issue on voice over wireless local area networks (VoWLAN), which aim to foster interaction among researchers from both academia and industry in networking, wireless communications, and mobile computing. The special issue includes an article investigating the issue of determining an appropriate pricing strategy for VoWLAN provisioning. Also featured are two articles on polling as a solution for supporting real-time traffic over WLANs and another on media optimization network architecture (MONA).     

掺铈石英闪烁光纤的伽马传感特性研究

提出了基于溶胶-凝胶(Sol-Gel)法制备掺铈石英闪烁光纤,将其作为辐射传感头,搭建了对伽马辐射敏感的光纤传感系统。通过改变溶胶-凝胶中铈元素掺杂浓度,分别拉制出Ce与Si的摩尔分数分别为0.14%和0.22%的闪烁石英光纤。利用137Cs伽马辐射源,研究了闪烁光纤涂覆层、铈元素掺杂浓度及闪烁光纤长度等参量对辐射传感特性的影响。     

Performance evaluation of LIBTA/hybrid time‐slot selection algorithm for cellular systems

This paper studies the performance of radio assignment algorithms for portable access in cellular systems. Several channel access procedures are proposed and simulated using block oriented network simulator (BONeS) simulation of a model 36‐port system. Simulation results exhibit that load‐sharing system with LIBTA algorithm is better than directed retry system with the same algorithm by around 0.9 erlangs while better than quasi‐fixed channel assignment (QFCA) system by around 2 erlangs if the grade of service (GOS) is constrained to less than 10 per cent. Plus, a hybrid time‐slot selection procedure is proposed to enhance the system performance. It is observed that systems with hybrid time‐slot selection perform better than those with LIBTA algorithm in GOS under heavy load. It is also observed that load sharing system with hybrid time‐slot selection algorithm is better than directed retry system with the same algorithm by around 0.7 erlangs and better than QFCA system by around 2 erlangs. Copyright © 2001 John Wiley & Sons, Ltd.     

面积优化再分解设计方法

在超大集成电路的设计过程中,库单元绑定是非常重要的一环。它的目标是通过特定的方法,把一组布尔网络表述的逻辑功能能用具体的库单元实现。逻辑分解是这一过程中非常重要的一步,经分解产生的主题图质量的好坏直接影响到最后的设计结果。本文针对主题图的面积优化问题,提出了“再分解”这一新设计方法,该方法采用“逻辑变换”技术,使主题图中门的娄量尽量减少,从而达到减小实际网表面积的目的。     

Low-density parity-check codes based on finite geometries: arediscovery and new results

This paper presents a geometric approach to the construction of low-density parity-check (LDPC) codes. Four classes of LDPC codes are constructed based on the lines and points of Euclidean and projective geometries over finite fields. Codes of these four classes have good minimum distances and their Tanner (1981) graphs have girth 6. Finite-geometry LDPC codes can be decoded in various ways, ranging from low to high decoding complexity and from reasonably good to very good performance. They perform very well with iterative decoding. Furthermore, they can be put in either cyclic or quasi-cyclic form. Consequently, their encoding can be achieved in linear time and implemented with simple feedback shift registers. This advantage is not shared by other LDPC codes in general and is important in practice. Finite-geometry LDPC codes can be extended and shortened in various ways to obtain other good LDPC codes. Several techniques of extension and shortening are presented. Long extended finite-geometry LDPC codes have been constructed and they achieve a performance only a few tenths of a decibel away from the Shannon theoretical limit with iterative decoding     

用3D-FDTD法分析用于近场光存储的光纤探针电磁波传输特性

提高近场光存储的存储信息密度的关键主要在于掌握近场存储光纤探针的透光率、近场光斑直径尺寸以及场梯度等近场物理量。采用三维时域有限差分 (3D FDTD)法分析了可用于近场光存储的光纤探针尖的光学性质 ,对不同类型光纤的近场光场分布进行了数值计算 ,给出结果并进行比较 ,从光学性质的角度对其在近场光存储中的应用加以讨论。完全镀膜光纤尖在极近场处的光斑可获得 10nm的尺寸 ,远小于传统光纤光学聚焦的光斑尺寸大小。     

Real Time Anomalous Trajectory Detection and Analysis

GPS-equipped taxis can be considered as pervasive sensors and the large-scale digital traces produced allow us to reveal many hidden facts about the city dynamics and human behaviors. In this paper we present a novel GPS-based taxi system which can detect ongoing anomalous passenger delivery behaviors leveraging our proposed iBOAT method. To achieve real time monitoring, we reduce the response time of iBOAT by more than five times with an inverted index mechanism adopted. We evaluate the effectiveness of the system with large scale real life taxi GPS records while serving 200,000 taxis. With this system, we obtain about 0.44 million anomalous trajectories out of 7.35 million taxi delivery trips, which correspond to 7600 taxis’ GPS records in one month time in the city of Hangzhou, China. Through further analysis of these anomalous trajectories, we observe that: (1) Over 60 % of the anomalous trajectories are “detours” that travel longer distances and time than normal trajectories; (2) The average trip length of drivers with high-detour tendency is 20 % longer than that of normal drivers; (3) The length of anomalous sub-trajectories is usually less than a third of the entire trip, and they tend to begin in the first two thirds of the journey; (4) Although longer distance results in a greater taxi fare, a higher tendency to take anomalous detours does not result in higher monthly revenue; and (5) Taxis with a higher income usually spend less time finding new passengers and deliver them in faster speed.     

Engineering Metal Nanoclusters for Targeted Therapeutics: From Targeting Strategies to Therapeutic Applications

Metal nanoclusters (NCs) have recently attracted great interest in biomedical applications due to their ultrasmall size, good biocompatibility, and unique molecule-like physical and chemical properties. Metal NCs can be rationally designed and integrated with various targeting moieties to achieve unique physicochemical properties and functions. For therapeutic applications, these multifunctional surface-modified NCs can provide distinctive advantages over native metal NCs, such as improved therapeutic effects and reduced side effects. In this review, the design principles of targeting strategies for metal NCs and their composites, including passive and active targeting, and physical and chemical targeting are first discussed. The authors then focus on the recent achievements in the application of metal NCs in targeted therapeutics, including chemotherapy, phototherapy, and radiotherapy. Finally, the authors’ perspectives on the challenges and opportunities of developing metal NCs in targeted therapeutics, further paving their way for potential clinical applications are provided.