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1.
本文研究三羟甲基丙烷单烯丙醚、双烯丙醚的合成方法及其在不饱和聚酯气干型改性应用。当选择5%摩尔量的四丁基溴化铵作相转移催化剂,50%NaOH,反应温度900170,无溶剂的条件理,产物含21.3%MATMP、73.8%DATMP和4.9%三羟甲基丙烷三烯丙醚,总收率为84.5%。  相似文献   

2.
首次制得二乙基胺甲基膦酸锆-亚磷酸锆Zr(HPO_3)_(2-x)·(O_3PCH_2NEt_2)_x·H_2O(ZDEAMP-ZP,x=0.75,0.60,0.50).将ZDEAMP-ZP用溴化苄季铵化,得到部分季铵化的产物:溴化苄基二乙基铵甲基膦酸锆-二乙基胺甲基膦酸锆-业磷酸锆Zr(HPO_3)_(2-x)·(O_3PCH_2NEt_2)_(x-y)·(O_3PCH_2N ̄+Et_2·CH_2Ph·Br ̄-)_y·H_2O(Y<X,ZBDEAMPB-ZDEAMP-ZP).ZBDEAMPB-ZDEAMP-ZP用于进行液/固/液或固固/液三相催化的亲核取代成醚、卤代烃和羧酸盐合成酯及二氯卡宾加成反应,均得到良好的结果。催化剂易于分离和回收,通常回收70%~100%,催化剂重复使用10次以上无明显失活。  相似文献   

3.
对31例糖尿病患者同时进行了脑电地形图(BEAM)和脑电图(EEG)观察,BEAM的典型改变是双侧多部位、不对称性的慢波功率谱增高;部分病例做了CT和经颅彩色多普勒(TCD)检查;上述方法对糖尿病性脑血管病变检出的阳性率分别是BEAM为80.6%、EEG为29.0%、CT为41.6%、TCD为61.5%,提示BEAM较EEOCT和TCD更为敏感,因而BEAM有可能成为一种早期诊治及预防糖尿病性脑血管病的无创伤性客观检测手段。  相似文献   

4.
用DSC(差示扫描量热法)研究三羟甲基乙烷CH3C(CH2OH)3(PG)和三羟甲基丙烷CH3CH2-C(CH2OH)3(TMP)二元系的混合物的贮热性能.PG和TMP具有固-固转变特性,其纯组分的转变温度分别为83℃和55℃附近.研究结果表明,随着PG浓度的增加,低温峰变小,高温峰形变大.尤其是在DSC测试中当第一次加热至固-固相变转化结束后,冷却至室温,再第二次加热,进行DSC测试,发现绝大多数PG/TMP二元系出现明显的唯一峰,且倾向高温峰方向,这表明TMP对该体系的低温贮热不利  相似文献   

5.
研究了三维MANDELBROT过程的SHEET-渗流问题,证明了当P>PS时,三维MANDELBROT过程的SHEET-渗流条数是几乎处处有限的,并且给出了其上界估计.参5.  相似文献   

6.
本文研究了1-苯基-3-甲基-4-(α-呋喃甲酰基)-5-吡唑酮(HA)单独萃取Y(Ⅲ)及其与二苯亚砜(DPSO),磷酸三丁酯(TBP)或三辛基氧膦(TOPO)协同萃取Y(Ⅲ)的行为。确定了萃合物的组成分别为YA_3,YA_3·DPSO,YA_3·TBP和YA_2(NO_3)·2TOPO.算得萃取平衡常数分别为:logK_(A(HA))=-6.86,1ogK_(AB(HA+DPSO))=-3.89,logK_(AB(HA+TBP))=-2.53和logK_(AB(HA+TOPO))=5.13.  相似文献   

7.
合成5种Eu(Ⅲ)-β-二酮-二苯胍三元配合物,经元素分析和化学分析测定其组成分别为Eu(AA)4.DPG(Ⅰ)、Eu(BA)4.DPG(Ⅱ)、Eu(DBM)4.DPG(Ⅲ)、Eu(PMBP)4.DPG(Ⅳ)和Eu(TTA)4.DPG(Ⅴ),用红外光谱、差热分析进行了表征,测定了配合物Ⅰ-Ⅳ在室温(298K)和液氮温度(77K)下的荧光发射光谱,应用群论方法和Judd-ofelt理论对低温精细光谱  相似文献   

8.
根据最小自由能方法计算了铝粉含量变化对NEPE,CMDB以及固体含量为88%的复合团体推进剂能量特性的影响.铝粉含量为5%~18%时,NEPE推进剂密度比冲分别比CMDB和复合团体推进剂增加11.1~14.6s·g/cm3和14.2~18.0s·g/cm3.通过对低特征信号NEPE推进剂配方燃烧性能的研究,观察到当A1含量为3%~5%时,采用3.5%的燃速催化剂仅可使压力指数降至0.60.相应高能NEPE(铝粉含量等于18%)推进剂的压力指数可降至0.56.而降低AP粒度和增加其含量是提高燃速和降低压力指数的有效措施之一.此外,还测定了NEPE推进剂的燃速温度敏感系数,并与CMDB和复合团体推进剂数据进行了对比.  相似文献   

9.
三羟甲基丙烷三丙烯酸酯合成新工艺   总被引:7,自引:0,他引:7  
以三羟甲基丙烷、丙烯酸为原料,D72大孔强酸型阳离子交换树脂为催化剂,苯为水夹带剂,合成三羟甲基丙烷三丙烯酸酯,考虑反应温度、原料配比、催化剂用量、反应时间等因素对产品酯化度的影响;初步探讨了不同脱水方式及阻聚剂对酯化反应以及粗产物的不同纯化方式对产品丙烯酸含量的影响,选出了TMPTA的最佳合成条件,最终产率70%,产品为浅黄色秀明液体,n25/D=1.6669,231时粘度423mPa。  相似文献   

10.
采用在反应过程中加入脱色剂的新的直接酯化法合成了三甲基丙烯酸三羟甲基丙互。产品色度≤35APHA,产品收率及纯度分别为91.9%和96.49%。考察了原料(三羟甲基丙烷)的纯度、反应温度等对产品色度的影响,研究了不同脱色剂对产品脱色效果。并对产品进行了GC、IR、^1HNMR、MS分析。  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.
<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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