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1.
使用DSC、IR研究了聚苯醚/双柠康酰亚胺体系的固化反应过程,得到了固化反应的平均表观活化能E为184.4kJ/mol,反应级数n接近1。固化后体系的理化性质变化明显(特别是不溶于氯仿),IR图谱的不显著,DSC行为与单独的聚苯醚相近。  相似文献   

2.
TiO2/BMI树脂固化反应及热性能研究   总被引:3,自引:0,他引:3  
利用热分析技术测定了纳米TiO2共混改性双马来酰亚按(BMI)树脂体系的固体反应参数,考察了固化条件与玻璃化温度之间的关系及纳米TiO2对固化树脂高温热分解性能的影响。研究结果表明,树脂中引入纳米TiO2,降低了固化反应活化能和树脂固化后处理温度,改善了BMI树脂的加工性能;树脂在N2中的超始热分解温度降低,但不改变热氧分解温度;TiO2/BMI固化树脂玻璃化温度高达302℃,热分解温度达420℃  相似文献   

3.
酚醛环氧树脂固化动力学研究   总被引:1,自引:0,他引:1  
实验先合成酚醛树脂,接着配制酚醛环氧树脂,并用热重分析法(TG)和差示扫描量法(DSC)对酚醛环氧树脂的固化过程进行了动力学研究,得出了该体系的动力学参数,其反应级数n=0.87、活化能E=49.18kJ/mol;同时分析验证了固化过程缩聚反应的存在,并给出了相关的工艺参数(固化工艺温度170℃,烘焙温度120℃).  相似文献   

4.
不饱和聚酯树脂/CaCO3体系固化动力学非等温DSC研究   总被引:3,自引:0,他引:3  
采用示差扫描量热(DSC)法对不饱和聚酯树脂(UP树脂)/CaCO3复合体系的固化过程进行研究,得出不同升温速率下UP树脂/CaCO3复合体系固化过程中的DSC曲线,并由动态DSC曲线求出固化反应的活化能、固化反应级数及动力学方程中的指前因子等参数,建立了复合体系固化反应动力学的数学模型。  相似文献   

5.
通过差示扫描量热法(DSC)研究了环氧端基酚酞聚芳醚腈(简称E-PCE树脂)与几种常用固化剂的热效应,测算了E-PCE/DDS固化体系固化过程的表观活化能及反应级数。另外,通过DSC、TGA测试了固化后试样的热性能。  相似文献   

6.
用差示扫描量热法(DSC)研究了三种磷酸盐类阻燃剂(磷酸二氢胺MAP、磷酸氢二铵DAP和聚磷酸铵APP)对脲醛树脂胶粘剂(UF)固化反应起始温度、反应速度以及最终固化程度的影响。结果表明:(1)APP和MAP可以降低阻燃胶粘剂的pH值,而DAP则使pH值升高;(2)APP和MAP可以降低UF胶固化反应活化能,使固化反应在较低的温度下开始,但相应的阻燃UF胶最终固化程度低于不加阻燃剂的UF胶;(3)  相似文献   

7.
焦炭反应性及反应后强度测试规范性(GB/T4000—2008)较强,洲试误差(CRI:r≤2.4%,CSR:r≤3.2%)较大的原因,对煤焦实骚中心现有焦炭反应性及反应后强度测定装王(中钢集团鞍山热能研究院有限公司,KF-200型)进行测试,以分析升温速率对焦炭反应性及反应后强度的影响。结果表明,在严格遵守目标(GB/T4000-2008)规定升温速率(8~16℃/min)内,升温速率对焦炭反应性及反应后强度无显著影响。  相似文献   

8.
以大孔强酸性阳离子交换树脂为催化剂进行了乙酸和正丁醇的酯化反应,研究了不同的催化剂用量、醇/醇摩尔比和温度对酯化反应的影响,得出较佳的工艺条件为2.52gcat/molHAc、醇/酸摩尔比为1和110~120℃,并从温度与酯化速度的关系求出反应级数(n),反应速度常数(k)和反应活化能(E).  相似文献   

9.
用差示扫描量热法研究了CDR-9418改性双马树脂固化反应动力学。从反应动力学基本方程出发,采用微分法得到等温固化反应表观活化能E、反应速率常数k和反应级数n。用基辛格(kissinger)方程,得出了不同升温速率下的非等温固化反应表观活化能和频率因子A,并用kissinger法估算出形状因子S和反应级数n。结果表明,等温反应级数和反应速率常数随固化温度提高而增大,460K时接近一级反应;而非等温反应级数随着升温速率的增大而减小。  相似文献   

10.
用密度泛函DFT(B3LYP)方法和MP2从头算方法,在6-311G(d,p),6-311++G(d,p)基组水平上研究了CO+HO2-C02+OH,CO+NO2-CO2+NO2个反应的过渡态结构和反应机理,沿IRC分析指出反应均为协同完成的一步反应.同时计算了2个反应的活化位垒和反应焓变,并与实验估计值进行了比较.对CO与H02的反应采用MP2/6—311++G(d,p)方法,计算所得反应位垒为100.98kJ/mol,与实验估计值93.60kJ/mol基本接近,对CO与N02的反应采用B3LYP/6—311++G(d,p)方法,计算所得反应位垒为115.99kJ/mol,比实验估计值141.51kJ/mol低25.52kJ/mol.计算同时表明2个反应均为放热反应.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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