Direct vapor phase growth process and robust photoluminescence properties of large area MoS2 layers

There has been growing research interest in the use of molybdenum disulfide in the fields of optoelectronics and energy harvesting devices, by virtue of its indirect-to-direct band gap tunability. However, obtaining large area thin films of MoS2 for future device applications still remains a challenge. In the present study, the amounts of the precursors （S and MOO3） were varied systematically in order to optimize the growth of highly crystalline and large area MoS2 layers by the chemical vapor deposition method. Careful control of the amounts of precursors was found to the key factor in the synthesis of large area highly crystalline flakes. The thickness of the layers was confirmed by Raman spectroscopy and atomic force microscopy. The optical properties and chemical composition were studied by photoluminescence （PL） and X-ray photoelectron spectroscopy. The emergence of strong direct excitonic emissions at 1.82 eV （A-exciton, with a normalized PL intensity of -55 × 10^3） and 1.98 eV （B-exciton, with a normalized PL intensity of -5 × 10^3） of the sample at room temperature clearly indicates the high luminescence quantum efficiency. The mobility of the films was found to be 0.09 cm^2/（V.s） at room temperature. This study provides a method for the controlled synthesis of high-quality two-dimensional （2D） transition metal dichalcogenide materials, useful for applications in nanodevices, optoelectronics and solar energv conversion.     

信息安全产品认证工厂检查中的几个常见问题

国家信息安全产品认证是信息安全产品领域的国家级产品认证,2008年1月,国家质检总局和国家认监委联合发布了《关于部分信息安全产品实施强制性认证的公告》,规定从2009年5月1日起,对8大类、13种信息安全产品实行强制性认证。2009年4月27日,财政部、国家质检总局和国家认监     

融合双分支动态偏好的会话推荐

针对基于会话的推荐算法仅对用户单一偏好进行静态建模而无法捕捉用户受环境影响偏好产生的波动, 从而降低推荐准确性的问题. 提出融合双分支动态偏好的会话推荐方法: 首先, 通过异构超图来建模不同类型信息, 设计双分支聚合机制获取以及整合异构超图中信息并且学习多类型节点之间的关系, 再用价格嵌入增强器来加强类别和价格之间关系; 其次, 设计双层偏好编码器, 其中采用多尺度时序Transformer提取用户动态价格偏好, 利用软注意机制和反向位置编码学习用户动态兴趣偏好; 最后, 用门控机制融合用户多类型动态偏好, 向用户进行推荐. 通过在Cosmetics和Diginetica-buy两个数据集上进行实验, 结果证明与其他对比算法相比在Precision和MRR评价指标中有显著的提升.     

MicroRNA-Based Diagnosis and Therapy

MicroRNAs (miRNAs) are a group of endogenous non-coding RNAs that regulate gene expression. Alteration in miRNA expression results in changes in the profile of genes involving a range of biological processes, contributing to numerous human disorders. With high stability in human fluids, miRNAs in the circulation are considered as promising biomarkers for diagnosis, as well as prognosis of disease. In addition, the translation of miRNA-based therapy from a research setting to clinical application has huge potential. The aim of the current review is to: (i) discuss how miRNAs traffic intracellularly and extracellularly; (ii) emphasize the role of circulating miRNAs as attractive potential biomarkers for diagnosis and prognosis; (iii) describe how circulating microRNA can be measured, emphasizing technical problems that may influence their relative levels; (iv) highlight some of the circulating miRNA panels available for clinical use; (v) discuss how miRNAs could be utilized as novel therapeutics, and finally (v) update those miRNA-based therapeutics clinical trials that could potentially lead to a breakthrough in the treatment of different human pathologies.     

对以太网无源光网络中OAM的分析

以太网无源光网络(EPON)作为一种新兴的接入技术,需要网络设计者提供电信级(Carrier-class)的管理能力,而单纯的简单网络管理协议(SNMP)已经不能胜任其运营、管理、维护(OAM)的要求.文章提出了基于802.3ahOAM协议和SNMP的EPON系统管理机制,并描述TEPON系统OAM的功能、特点以及在Linux操作系统下该刚络管理机制的软件实现方案.     

自定义服务质量模型的网格工作流调度算法

随着网格服务应用的发展,在网格工作流中,复杂的任务可以由多个独立的服务,通过工作流引擎等方式组合成新服务后完成。在组合服务的过程中,由不同服务提供商提供的候选服务,具有不同的服务质量参数,在网格工作流调度中,需要满足用户定义的服务质量约束。提出了方便用户定义的服务质量模型,并且在该模型的基础上,改进了网格工作流调度算法,通过实验分析证明改进后的算法优于传统的调度算法。     

Known-key distinguishers on type-1 Feistel scheme and near-collision attacks on its hashing modes

We present some known-key distinguishers for a type-1 Feistel scheme with a permutation as the round function. To be more specific, the 29-round known-key truncated differential distinguishers are given for the 256-bit type-1 Feistel scheme with an SP (substitution-permutation) round function by using the rebound attack, where the S -boxes have perfect differential and linear properties and the linear diffusion layer has a maximum branch number. For two 128-bit versions, the distinguishers can be applied on 25-round structures. Based on these distinguishers, we construct near-collision attacks on these schemes with MMO (Matyas-Meyer-Oseas) and MP (Miyaguchi-Preneel) hashing modes, and propose the 26-round and 22-round near-collision attacks for two 256-bit schemes and two 128-bit schemes, respectively. We apply the near-collision attack on MAME and obtain a 26-round near-collision attack. Using the algebraic degree and some integral properties, we prove the correctness of the 31-round known-key integral distinguisher proposed by Sasaki et al. We show that if the round function is a permutation, the integral distinguisher is suitable for a type-1 Feistel scheme of any size.     

舰船消磁可视化界面设计与实现

随着测磁和消磁硬件设备的快速发展,急切需要先进的测、消磁软件与之配合来高效地完成消磁任务,提出了基于虚拟仪器设计软件LabWindows/CVI和科学计算软件Matlab开发舰船消磁可视化界面的整体软件结构,推导了从实际测量深度到标准测量深度的磁场换算算法,通过Active技术实现两种软件接口调用,分析了舰船磁场的可视化描述和特征信息提取方法;在LabWindos/CVI平台下开发了舰船消磁可视化界面,调用Matlab完成磁场换算和数据预处理,充分利用了两种软件的优势;整体界面美观、操作方便、附加多种有用功能,实现了友好的人机交互。