Performance improvement of continuous carbon nanotube fibers by acid treatment

Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers' properties.After HCISO_3 treatment for 2 h,the fibers' strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G' band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.     

Free-standing,curled and partially reduced graphene oxide network as sulfur host for high-performance lithium–sulfur batteries

Lithium–sulfur(Li–S) batteries have received more and more attention because of higher specific capacity and energy density of sulfur than current lithium–ion batteries. However, the low electrical conductivity of sulfur and its discharge product, and also the high dissolution of polysulfides restrict the Li–S battery practical applications. To improve their performances, in this work, we fabricate a novel free-standing, curled and partially reduced graphene oxide(CPrGO for short) network and combine it with sulfur to form a CPrGO–S composite as a cathode for Li–S battery. With sulfur content of 60 wt%, the free-standing CPrGO–S composite network delievers an initial capacity of 988.9 m Ah·g~(-1). After 200 cycles,it shows a stable capacity of 841.4 m Ah·g~(-1) at 0.2 C, retaining about 85% of the initial value. The high electrochemical performance demonstrates that the CPrGO–S network has great potential applications in energy storage system. Such improved properties can be ascribed to the unique free-standing and continous CPrGO–S network which has high specific surface area and good electrical conductivity. In addition, oxygen-containing groups on the partially reduced graphene oxide are beneficial to preventing the polysulfides from dissolving into electrolyte and can mitigate the "shuttle effect".     

Highly flexible and excellent performance continuous carbon nanotube fibrous thermoelectric modules for diversified applications

A highly flexible and continuous fibrous thermoelectric (TE) module with high-performance has been fabricated based on an ultra-long single-walled carbon nanotube fiber, which effectively avoids the drawbacks of traditional inorganic TE based modules. The maximum output power density of a 1-cm long fibrous TE module with 8 p-n pairs can reach to 3436 μW·cm^-2, the power per unit weight to 2034 μW·g^-1, at a steady-state temperature difference of 50 K. The continuous fibrous TE module is used to detect temperature change of a single point, which exhibits a good responsiveness and excellent stability. Because of its adjustability in length, the flexible fibrous TE module can satisfy the transformation of the temperature difference between two distant heat sources into electrical energy. Based on the signal of the as-fabricated TE module, a multi-region recognizer has been designed and demonstrated. The highly flexible and continuous fibrous TE module with excellent performance shows a great potential in diversified applications of TE generation, temperature detection, and position identification.     

一种二次保形插值参数曲面

1．引言保形插值是工业设计和制造中经常遇到的问题，有关这方面的研究已有许多文献【‘－u1．设n二Fx；，yi，人，川7一0，1，…；n；j＝0；l，…，。；x；＜x；＋1．l＝0，1，…．n—1；yi＜的十；，J二O，L…，。一卫｝是一给定的数据集，Cadson和［ltsch、Beatson和zejerJ－1985年分别提出的方法只保持被插数据集的轴向单调性；Dodd和Roulier等人于1983和1987年提出的方法只保持被插点集网格线上的轴向凸凹性和单调性；Constantini和FOntanella于1990年提出的方法可保持被插点集在所有于区域的边界及共内部的轴向凸凹性和单调性；…     

Dependence of the solar cell performance on nanocarbon/Si heterojunctions

Solar cells that combine single-crystalline silicon(Si) with graphene(G) have been widely researched in order to develop next-generation photovoltaic devices. However, the power conversion efficiency(PCE) of G/Si solar cell without chemical doping is commonly low due to the relatively high resistance of graphene. In this work, through combining graphene with carbon nanotube(CNT) networks, we fabricated three kinds of hybrid nanocarbon film/Si heterojunction solar cells in order to increase the PCE of the graphene based Si solar cell. We investigated the characteristics of different nanocarbon film/Si solar cells and found that their performance depends on the heterojunctions. Specifically, a doping-free G-CNT/Si solar cell demonstrated a high PCE of 7.9%, which is nearly equal to the combined value of two individuals(G/Si and CNT/Si). This high efficiency is attributed to the synergistic effect of graphene and CNTs, and can be further increased to 9.1% after applying a PMMA antireflection coating. This study provides a potential way to further improve the Si based heterojunction solar cells.     

艺术类专业考试网上报名系统的设计与实现

在此主要描述了艺术类专业考试网上报名系统的设计与实现过程,该系统采用B/S模式,实现了考生报名、考场安排、成绩管理等一体化功能,大大缩短了考生报名和考试组织工作的时间。详细介绍了系统的开发环境、功能设计和数据库设计环节,重点阐述了系统的主要功能及其实现的关键技术。     

业务平台安全解决方案研究

电信业务平台作为重要的支撑系统,需确保业务系统及各类信息数据的安全,尽量避免安全事件带来的负面影响及经济损失.从实际出发,通过调研及问题溯源分析,阐述电信业务平台安全方面的几个典型问题,以流程为切入点,结合管理和技术两个维度,探讨研究业务平台安全问题的解决方案.     

基于嵌入式Linux的莫尔斯码报务实训系统设计

介绍一款基于嵌入式Linux平台的莫尔斯码报务实训系统。该实训系统具有收发报功能,并且将识别判断的结果显示到硬件设备上的LCD显示屏上。同时采用了等距离判定法和递减的修正因子的方法来动态的计算判定阈值,实现了莫尔斯码的识别速度、准确性和适应性之间的平衡。在程序中自适应的莫尔斯电码的识别的过程由3部分组成:点划码识别、自适应处理和字符识别。系统同时还提供了练习功能以及训练文本编辑等辅助功能。     

MPEG-4视频标准及其关键算法

MPEG-4引入了视频对象的概念,有效地支持基于内容的图像编码,对不同的视频源标准格式和不同的视频码率提供有效的编码,以满足众多多媒体的应用需求。本文系统地分析了MPEG-4视频编码算法,对MPEG-4视频标准的关键概念进行了详细的解释。     

HR-HPV基因联合TV-CDFI在宫颈癌筛查及诊断中的应用

本研究探讨高危人乳头瘤病毒(HR-HPV)基因检查联合经阴道彩色多普勒超声(TV-CDFI)在宫颈癌筛查及诊断中的应用价值。选取84例宫颈癌患者(宫颈癌组)、100例宫颈上皮瘤变患者(CIN组)、100例宫颈炎患者(炎性组),三组患者采用HPV E6/E7 mRNA检测法、第二代杂交捕获(HC2)技术法检测宫颈组织中HPV感染阳性率,以病理学结果作为金标准分析两种方法鉴别诊断宫颈癌与宫颈上皮瘤变的价值;采用TV-CDFI检测宫颈癌Adler分级。结果显示,HPV E6/E7 mRNA检测法鉴别诊断宫颈癌与CIN患者的灵敏度为95.24%、特异度为20.00%;HC2法鉴别诊断宫颈癌与CIN患者的灵敏度为97.62%、特异度为17.00%;HPV E6/E7 mRNA检测法鉴别诊断宫颈癌与宫颈炎患者的灵敏度为95.24%、特异度为89.00%;HC2法鉴别诊断宫颈癌与宫颈炎患者的灵敏度为97.62%、特异度为92.00%。HPV E6/E7 mRNA检测法、HC2法鉴别诊断宫颈炎与宫颈癌方面具有较高的临床价值,TV-CDFI检测宫颈癌Adler分级与疾病进展关系密切,因此,宫颈癌筛查时将...