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1.
本实验,首先根据铈易被氧化成四价铈的性质,使Ce(OH)3lfnywx o C(OH)4.须稀酸(PH≈2.5)中,Ce(OH)4不溶解,而E(OH)3能溶解,使铈与其他轻稀土元素得到初级分离,再根据四价铈容易被磷酸三丁酯(TBP)萃取的性质,使铈得到进一步纯化,后经草酸沉淀、过滤、灼烧得到纯的二氧化铈。  相似文献   

2.
硬脂酸改性Mg(OH)2的机理及对EVA性能的影响   总被引:1,自引:0,他引:1  
采用FTIR表征硬脂酸对氢氧化镁Mg(OH)2的改性效果,发现不存在一个所谓的“最佳量”,分析认为硬脂酸对Mg(OH)2表面改性既包括着 硬脂酸—COOH与Mg(OH)2的—OH之间的弱酯化反应,也包含着酸与弱碱Mg(OH)2之间的酸碱反应,所以硬脂酸对Mg(OH)2的表面改性随硬脂酸用量 增加而持续进行。此外,改性剂用量也对Mg(OH)2填充乙烯-醛酸乙烯酯共聚物(EVA)体系性能存在显著的影响。与填充未处理Mg(OH)2体系相比 较,表面改性剂用量的增加会导致复合材料的拉伸强度的不断下降,断裂伸长率的增加和阻燃性能的急剧恶化。但是,复合材料的表观黏度下 降,加工性能得到改善。  相似文献   

3.
NO与OH自由基反应机理的理论研究   总被引:1,自引:5,他引:1  
用MP2方法,在6-311 G(d,p)基组水平上研究了NO与OH自由基反应的微观机理,全参数优化了反应过程中各反应物、中间体、过渡态和产物的几何构型,考虑零点能校正,同时采用QCISD(T)/6-311 G(d,p)方法得到了更为精确的能量.振动分析结果证实了中间体和过渡态的真实性,IRC计算结果进一步证实了过渡态的真实性.从对NO与OH自由基反应机理的研究结果看,NO与OH自由基反应为双通道反应过程,分别为:NO OH→IM1→TS1→NO2 H,NO OH→IM1→TS2→IM2(HNO2).研究发现,通道NO OH→IM1→TS2→IM2(HNO2)是NO与OH自由基反应的主反应通道,其主要产物是HNO2.  相似文献   

4.
系统研究了纯化冶金级Al(OH)3的工艺参数,通过对影响碱溶及纯化的因素进行试验,探索出碱溶除去Al(OH)3中晶间碱,获得Na20合量<0.003%的低钠Al(OH)3的新方法,得出最佳工艺条件.  相似文献   

5.
使用循环放电法,研究在储氢合金中添加适量的钴系添加剂后的电化学性能。结果表明:添加Co、CoO、Co(OH)2的MH电极0.2C放电容量可以从原来的283mAh/g(Alloy),提高到313ma/g(Alloy Co)、291mAh/g(Alloy CoO)及315mAh/g(Alloy Co(OH)2),同时在电极中加入Co、CoO、Co(OH)2后,电极在放电过程中发生了Co的氧化反应,为电极提供了容量。  相似文献   

6.
在CCSD(T)/6-311++G(d,p)/M05-2X/6-311++G(d,p)理论水平上,研究对流层中甲基丙醚(MnPE)与·OH的氧化反应机理。发现MnPE初始反应主要是·OH与α-C上的H反应生成高活性的中间体(C中心自由基),主产物为丙酸甲酯(P1)、甲酸甲酯(P5)和乙醛(P6),副产物有丙醛(P3)、甲醛(P4)和环氧基(P2)等,计算得到在298 K下MnPE与·OH的反应速率常数为1.01×10-12 cm3·molecule-1·s-1,在200~400 K温度范围内,随着温度的升高,·OH提取Cα’上的H路径的分支比逐渐增大,·OH提取Cα上的H路径的分支比呈现先增后减的趋势。  相似文献   

7.
以聚丙烯(PP)为基料、Mg(OH)2/Al3/P为复合阻燃剂。通过熔融共混制备PP无卤阻燃复合材料。对材料的阻燃性能和力学性能进行了测定。实验结果表明:当PP:Mg(OH)2:Al(OH)2:P为100:50:50:5时,混合物的阻燃性能和力学性能均能满足使用要求。填加纤维状Mg(0H)2的材料要比填加球状Mg(OH)2体系的拉伸强度优异。  相似文献   

8.
官能团化聚丙烯对Mg(OH)2/PP断裂形态的影响   总被引:4,自引:0,他引:4  
制备了Mg(OH)2/PP及其官能团化聚丙烯(FPP),丙烯酸(AA)改性复合材料,用SEM研究了复合材料的冲击与弯曲断口形态。研究表明FPP或AA加入及其在DCP存在AA原位形成FPP强化Mg(OH)2)/PP复合材料中粒子与基体间的相互作用。改善界面黏结和改变复合材料的断裂行为。原位形成FPP改性Mg(OH)2/PP复合材料中作用更加明显,但其作用效果与AA,Mg(OH)2用量有关。  相似文献   

9.
氢氧化镁和氢氧化铝阻燃高密度聚乙烯的研究   总被引:6,自引:0,他引:6  
Mg(OH)_2、Al(OH)_3是当前正在发展的无毒廉价的阻燃剂,本文利用它们研制无毒阻燃性HDPE。实验结果表明:Mg(OH)_2对HDPE的阻燃效果优于Al(OH)_3,但填充量较少;Mg(OH)_2与Al(OH)_3混合使用时对HDPE具有阻燃协同效应;依赖这种协同效应,用较少量的Mg(OH)_2和较多量的Al(OH)_3混合填充,可获得性能更好的阻燃性HDPE。实验结果还表明:加入少量偶联剂和交联剂DCP,可以提高阻燃性HDPE的拉伸强度。  相似文献   

10.
铁渣是在硫酸镍净化过程中和除铁时形成的。它的主要成份是Fe(OH)_3、Ni(OH)_2,NiSO_4、CaSO_4、Cu(OH)_2和少量Fe(OH)_2等,我厂铁渣中镍含量为~8%。为了回收上述渣中的镍,采用氨浸法,本法是用含NH_4HCO_3的氨溶液,在常温常压下直接浸出,Ni(OH)_2、Cu(OH)_2与氨水作用形成Ni(NH_3)~(++)_6、Cu(NH_3)~(++)_4络离子,而Fe(OH)_3、Fe(OH)_2则不溶于氨水,利用这个性质,可使镍铜与大量的氢氧化铁分离,达到回收镍的目的,本试验采用~8%样品。  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.
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   

13.
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   

14.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
<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   

20.
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