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Search Results: 1 - 10 of 251458 matches for " 张曦 "
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硅橡胶/云母/氧化硅系热性能和陶瓷化机理
Thermal Property and Ceramic Mechanism of Silicone/Mica/Silicone Oxide
 [PDF]

, 秦岩
Material Sciences (MS) , 2014, DOI: 10.12677/MS.2014.46035
Abstract:
采用甲基乙烯基苯基硅橡胶为基体,添加成瓷填料云母粉、补强填料气相二氧化硅制备在高温下可形成自支撑陶瓷体的烧蚀材料。通过TG-DSC测试其在室温至1000℃过程中的热性能变化。并采用FTIR和XRD分析在不同温度下燃烧产物的成分组成及其变化。结果表明,当云母粉的添加量为40份时,在1000℃时残留率约为66.21%,在600℃以上成瓷填料与硅橡胶开始发生从有机相向无机相转变的陶瓷化反应,而且随着温度的升高,成瓷化程度逐渐加深。由此简述陶瓷化机理,硅橡胶分解产生的二氧化硅与云母粉发生反应,在填料边缘处形成起桥接作用的共熔混合物,冷却后形成陶瓷化产物。
In this paper, methyl vinyl Phenyl Polysiloxane rubber (PVMQ) ablative composite filled with mica and silicone oxide was prepared. Its thermal properties were tested by TG-DSC analysis from room temperature to 1000?C. After it was fired at different temperatures, the products were analyzed by Fourier transform infrared spectrometer and X-ray diffraction. The results showed that when the addition of mica was 40, the residual rate at 1000?C was 66.21%. When the temperature was above 600?C, the filler and organic silicon rubber started to transform from organic to inorganic. As temperature rose, the extent of porcelain was gradually deepened. So the ceramic mechanism of the composite could be described that the silicon oxide decomposed from silicon rubber reacted with mica. Then eutectic mixture which had a bridge effect was formed at the edge of fillers and the ceramic products were obtained when cooled down.
绝对暗喻——概念隐喻理论视角的庞德隐喻翻译研究

华东师范大学学报(哲学社会科学版) , 2012,
Abstract: 概念隐喻理论认为,人类赖以思维和行动的概念体系本质上具有隐喻性,人类的思维过程就是以一个概念去理解或表达另一个概念。庞德是意象派诗歌的创始人,也是著作颇丰的翻译家,庞德提出的绝对暗喻概念体现了隐喻和思维之间的紧密联系。概念隐喻理论说明隐喻翻译的成功要取决于译文读者的思维能力,译文是译者与译文读者在思维能力上的融合。庞德的翻译以创造性翻译著称,却在多数译文中忠实地还原了原文隐喻的思维过程。本文从隐喻体现思维的角度分析庞德的绝对暗喻,展开隐喻翻译的新视角。
一起主变低后备疑似误动作事件综合分析
Synthetic Fault Analysis of a Relay Protection Override Trip
 [PDF]

顾仲德, , 屠旻
Smart Grid (SG) , 2012, DOI: 10.12677/SG.2012.24013
Abstract: 本文对某变电所主变低后备动作事件进行原因查找分析,根据事故前运行方式和有关开关继电保护故障录波图,对罕见的保护装置拒动故障、线路复合故障进行了分析,重现了故障的发生、扩大过程,并提出了切实可行的解决方案和运行建议。
In this paper the author try to find the reasons led to the relay protection override trip in 10 kV system. Analysis is conducted directing at the phenomena, relay protection diagrams and experiment data. In the end the author put forward the workable solution and suggestion.
SAMI. Path Verification Protocol for Web Service and its Performance Analysis
面向Web服务的SAML路径验证协议及其性能分析

,
计算机科学 , 2013,
Abstract: 基于PKI的签名机制在保护SAMI、断言传递时存在增加SOAP消息长度、显著降低Wcb服务响应速度的 问题。为此,提出了基于身份聚合签名的SAML路径验证(
BOT项目经济风险指标及其度量方法
俞波,
福州大学学报(自然科学版) , 2004,
Abstract: 针对项目经济变量的时间函数和预测值的函数分布,提出了BOT项目经济风险指标的计算表达式.应用模拟计算方法求得各经济风险指标的期望值及其分布形式,对项目经济风险进行度量,并根据投资商对风险的好恶程度,进行项目风险决策.
技术并购后整合对被兼并方创新能力的影响:社会资本的视角
,方圆
科技进步与对策 , 2014, DOI: 10.6049/kjjbydc.2013080812
Abstract: 关于并购后的整合对被兼并企业创新的影响,现有研究存在相互矛盾的观点――知识基础理论的预测是模棱两可的,而产权理论和代理理论的预测是负面的。为了调和这些争论,从社会资本理论视角解释了整合对被兼并企业创新的影响机制。通过区分整合过程的两条作用路径,认为整合破坏了被兼并方原有的社会联系,却有助于形成与兼并方之间新的社会联系。根据社会资本理论,被兼并企业原社会纽带的破坏稀释了团结型资本,而新社会纽带的形成增加了桥接型资本。这两条相反路径解释了整合对被兼并企业创新的影响机制。在此基础上,进一步探讨了环境动态性的调节作用。技术并购创新社会资本被兼并企业环境动态性
酞菁铅在石墨烯表面吸附行为的拉曼光谱研究
,
物理化学学报 , 2012,
Abstract: 利用石墨烯增强拉曼散射效应可以获得与石墨烯接触的某些分子的拉曼增强信号,并且对于不同的分子或振动模,其拉曼增强因子不同.根据这一特征,本工作利用拉曼光谱技术对石墨烯表面上酞菁铅(pbpc)分子langmuir-blodgett(lb)膜在退火过程中吸附构型的变化进行了跟踪研究.发现随着退火温度的升高,石墨烯表面上pbpc分子的拉曼信号经历了一个先增强后减弱的过程,在升华温度点附近强度达到最大,表明pbpc发生了由直立向平躺取向的转变;同时,在pbpc分子升华温度点附近,由于对称性破坏导致散射截面低的振动模出现,并且该振动模强度随着退火温度的进一步升高而增强,表明非平面的pbpc分子受石墨烯π-π相互作用的影响而形变加剧,向平面结构转变;在更高的退火温度下,则出现一些不属于pbpc分子的拉曼振动峰,表明pbpc分子在石墨烯表面由pb(ii)被还原成pb(0).
面向web服务的saml路径验证协议及其性能分析
,
计算机科学 , 2013,
Abstract: 基于pki的签名机制在保护sami、断言传递时存在增加soap消息长度、显著降低wcb服务响应速度的问题。为此,提出了基于身份聚合签名的saml路径验证(
基于牛顿插值的manet能量有效路由机制
鹿,
计算机应用 , 2007,
Abstract: ?移动adhoc网络中的一个主要问题是节点的能量有限。因此,许多研究侧重于减少能量消耗。提出一种基于牛顿插值的能量有效路由机制,首先根据节点的剩余电池能量和流经该节点的当前流量大小,计算出该节点的寿命;从寿命较长的节点中,选择当前状态下的最小功率路由。这样不仅保证了各节点的能量均衡问题,而且考虑到整个网络的最小功率路由。实验模拟结果显示,与以前算法相比,其具有更好的性能。
使用调制相移法测量光纤色散的研究
A Study of Dispersion Measurement for Optical Fiber by Phase-Modulation Method
 [PDF]

, 刘小英, 周镇辉
Optoelectronics (OE) , 2012, DOI: 10.12677/OE.2012.24004
Abstract:

光纤通信已经成为目前通信网络发展的主流方向。但是随着光纤通信系统向着超远距离、超大容量、超高速率的方向发展,光纤色散已经成为其巨大的阻碍。如何有效地控制光通信系统中产生的色散,使光信号在大容量、高速率、长距离传输中无误码地到达接收端,已经成为人们迫切需要解决的问题。对光通信系统中的色散进行监测并进行动态补偿的研究,使得超大容量、超长距离、超高速率的光纤通信系统成为可能,有助于最终实现全光智能自动交换网络。在众多测量光纤色散的方法中,调制相移法具有结构简单,可靠性强等优点。本文中,我们对使用调制相移法测量光纤色散进行了研究和仿真,讨论了在不同光纤长度和不同调制频率下,影响调制相移法测量结果精度的因素。通过适当地选取调制频率,我们可以使用调制相移法测得不同光纤长度下色散的精确值。另外在本文中,我们通过仿真验证了调制相移法可以测量具有任意色散波长曲线的光纤。因此在实际应用中,调制相移法是可以应用于高精度光纤色散的测量。

Optical fiber communication is the mainstream of communication development at present. However, with the development of optical fiber communication system which trending towards ultra-long length, ultra-large capacity and ultra-high speed, fiber dispersion turned to be a great obstacle. How to control the dispersion created in the optical communication system effectively while force optical signal to reach the receiving end in high-capacity, high-rate and error-free long-distance transmission has increasingly become a research focus of optical fiber communication systems. It is a great significance to research about monitor and dynamic compensate dispersion in the optical communication systems, so that the ultra-large capacity, ultra-long length and ultra-high speed optical fiber communication systems would not be impossible, all-optical intelligent network with automatic switching functions would come true. Among the varieties of methods to measure fiber dispersion, the phase-modulation shift method is the unique one, which has the advantages of simple structure, high reliability. In this paper, we make a research and simulate to use the phase-modulation shift method, meanwhile we also discuss about the factors which affect the accuracy of the results in the different fiber lengths and modulation frequencies. By the means that selecting appropriate modulation frequency, we can use modulation phase shift method to measure the exact value of dispersion comes out from different lengths of fiber. Moreover, this paper also proves that the phase-modulation shift method is able to measure the optical fiber with arbitrary dispersion-wavelength curve, which is already verified by our simulation. Therefore, the phase-modulation shift method is well to be applied to take practice in the high-precision fiber dispersion measurement.

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