一种基于数据划分的字符串相似连接外存算法

字符串相似连接操作具有广泛应用,因而将着重研究基于编辑距离的字符串相似连接。而现有的字符串相似连接算法大多为内存算法。实际应用中的数据集越来越大,有必要针对超大规模数据集研制字符串相似性连接外存算法。利用组合频率向量划分数据集,并提出了基于编辑距离的字符串相似性连接外存算法框架,证明了磁盘调度问题的难度并提出了不同的启发式磁盘调度方法。此外,还提出了基于该外存算法框架实现字符串相似性连接增量式计算的方法。实验结果表明,数据划分方法可以有效地过滤不相关的数据子集;磁盘调度算法能够有效减少磁盘IO次数;外存算法是高效的;增量式计算方法能够高效地处理数据更新。     

Recent progress of physical failure analysis of GaN HEMTs

Gallium nitride (GaN)-based high-electron mobility transistors (HEMTs) are widely used in high power and high frequency application fields,due to the outstanding physical and chemical properties of the GaN material.However,GaN HEMTs suffer from degradations and even failures during practical applications,making physical analyses of post-failure devices extremely significant for reliability improvements and further device optimizations.In this paper,common physical characterization techniques for post failure analyses are introduced,several failure mechanisms and corresponding failure phenomena are reviewed and summarized,and finally device optimization methods are discussed.     

新概念动能武器-电磁炮

电磁炮是现代战争中的一代新概念武器,目前国外的技术发展已达到实用阶段.用物理学中关于电流的磁场、电磁感应和涡流的基本理论对轨道炮、线圈炮、重接炮三种电磁炮的基本原理进行了分析;研究了轨道炮、线圈炮、重接炮的特点、应用前景;探讨了脉冲电源技术、材料技术、发射装置设计等电磁炮关键技术;最后总结了电磁炮的发展现状,展望了未来...     

退火工艺对钨丝/锆基非晶合金复合材料动态力学性能及断裂模式的影响

研究了体积含量为60％的钨丝/锆基复合材料在经过退火处理后,材料的应力-应变响应和动态断裂特征以及断口形貌。利用Hopkingson压杆冲击加载装置和扫描电镜(SEM)以及X射线衍射仪(XRD),对Φ5mm×5mm的圆柱形试样进行了相关研究。研究表明,钨丝体积含量为60％的钨丝/锆基复合材料在经过退火处理后,非晶基体出现了明显的晶化现象;材料在退火后动态压缩强度比退火前有明显降低;退火后非晶基体断口形貌由退火前的完全的脉络花样转变为河流花样和脉络花样混合模式;经过动态冲击后,钨丝的断裂模式在退火前后变化大。     

Electrochemical Oxidation of 5-Hydroxymethylfurfural on CeO2-Modified Co3O4 with Regulated Intermediate Adsorption and Promoted Charge Transfer

Electrocatalytic 5-hydroxymethylfurfural oxidation reaction (HMFOR) can replace the kinetically slow oxygen evolution reaction to yield high value-added chemicals. In this study, interface engineering is constructed by modifying CeO₂ nanoparticles on Co₃O₄ nanowires supported by nickel foam (NF). The construction of the heterointerface can facilitate the structural evolution of catalysts and charge transfer, as a result, the successfully synthesized NF@Co₃O₄/CeO₂ exhibits higher 5-hydroxymethylfurfural conversion (98.0%), 2,5-furandicarboxylic acid (FDCA) yield (94.5%), and Faradaic efficiency (97.5%) at a low electrolysis potential of 1.40 V_RHE compared to NF@Co₃O₄ and NF@CeO₂. Density-functional theory calculations indicate that the establishment of heterointerface can effectively regulate the intermediate adsorption and promote electron transfer, which greatly reduces the activation energy of the dehydrogenation step in 5-formyl-2-furancarboxylic acid (FFCA), and promotes the further oxidation of FFCA to FDCA, thereby improving the performance of HMFOR. In this study, the HMFOR behavior of the Co₃O₄/CeO₂ interface effect is deeply explored, which provides guidance for the future design of heterointerface catalysts with efficient HMFOR performance.     

基于固定电话网的中文短信息终端开发

研究了基于固定电话网（PSTN）的采用中文信息终端服务接口通信协议（CTSI）的短消息终（CPE）的软硬件开发。介绍了短信编辑接收系统与信息终端之间数据交换的协议,并以电子订货系统中发送订单为例,描述了信息终端与CTSI服务器之间链路建立、信息交互的整个过程。     

Amplifying Nanoparticle Targeting Performance to Tumor via Diels–Alder Cycloaddition

Traditional targeting approach utilizing biological ligands has to face the problems of limited receptors and tumor heterogeneity. Herein, a two‐step tumor‐targeting and therapy strategy based on inverse electron‐demand [4+2] Diels–Alder cycloaddition (iEDDA) is described. Owing to the unique acidic tumor microenvironment, an intravenous injection of tetrazine modified pH (low) insertion peptide could efficiently target and incorporate onto various cell surfaces in tumor tissue, such as cancer cells, vascular endothelial cells, and tumor‐associated fibroblasts. The “receptor‐like” tetrazine groups with a large amount and homogeneous intratumoral distribution could then serve as the baits to greatly amplify the tumor‐targeting ability of indocyanine green (ICG)‐loaded and trans‐cyclooctene (TCO)‐conjugated human serum albumin (HSA) nanoparticles (TCO‐HSA‐ICG NPs) via iEDDA after the second intravenous injection. Compared with the passive enhanced permeability and retention (EPR) effect and traditional active targeting approaches, the targeting performance and photothermal therapeutic effect based on the two‐step strategy are significantly enhanced, while no notable toxicity is observed. As acidity is a characteristic of solid tumor, the two‐step strategy can serve as a universal and promising modality for safe and high‐performance nanoparticle‐based antitumor therapy.     

AlGaAs／AlAs体系DBR的MOCVD生长及表征

设计并利用MOCVD在（311）GaAs衬底上生长了12．5个周期的Al0．6Ga0．4As／AlAs黄绿光分布式Bragg反射（DBR）体系，测量了白光反光谱及其外延片峰值波长分布，反射率90％以上，波长不均匀性在1．0％以下；利用了X射线双晶衍射对其进行结构表征，580nm波长DBR结构周期为84．5nm。     

一个嵌入式积相关电路的设计与实现

在嵌入式系统小型化和高速化的要求趋势下，实时图像处理系统中用通用DSP或专用集成电路来实现算法的计算和控制有一定的不足。文章讨论了一个以通用DSP和FPGA构成的实时图像处理系统的设计方法，最后对某一具体实时图象处理系统设计方案做了阐述。