1,1,1,3,5,5,5-七甲基-3-[2-(三甲氧基硅烷基)乙基]三硅氧烷的合成与表征

以七甲基三硅氧烷(MDHM)、乙烯基三甲氧基硅烷(VTMS)为原料,氯铂酸的异丙醇溶液为催化剂,采用硅氢加成反应,在氮气保护下合成1,1,1,3,5,5,5-七甲基-3-[2-(三甲氧基硅烷基)乙基]三硅氧烷(β-HTEOs),并用气相色谱-色谱连用(GC-MS)、核磁共振谱(1H-NMR、29 Si-NMR)、傅里叶红外变化光谱(FT-IR)对合成产物进行表征;通过探讨反应温度、反应时间、原料配比以及催化剂浓度对硅氢加成反应的影响,得到β-HTEOs合成的最优化条件,采用视频接触角仪测定其在玻璃基材上润湿铺展情况,表明β-HTEOs在玻璃基材上完全铺展,具有较低的表面张力.     

聚醚改性三硅氧烷的合成工艺研究

以1,1,1,3,5,5,5-七甲基三硅氧烷和丙烯基聚醚为原料,氯铂酸为催化剂,异丙醇为溶剂,通过硅氢加成反应合成出聚醚改性三硅氧烷。研究了反应温度、物料比、活化温度和时间、催化剂用量、反应时间对七甲基三硅氧烷的转化率的影响,并且对产物的表面张力性能进行测试。得出了较佳反应条件:反应温度100℃、烯丙基聚醚与七甲基三硅氧烷的物质的量比为1.2:1、活化温度60℃、活化时间为30min、氯铂酸相对三硅氧烷的质量分数为0.0015%、反应时间2h。此反应条件下三硅氧烷的转化率为99.34%,临界胶束浓度CMC为1.71×10-4mol/L,临界胶束浓度下的表面张力为20.19mN/m,其水溶液在pH值为5~9的条件下不易分解可以存放1个月。     

含氢聚甲基硅氧烷的合成与表征

以八甲基环四硅氧烷(D4)、四甲基四氢环四硅氧烷(D4H)和六甲基二硅氧烷(MM)为原料,以强酸性离子交换树脂为催化剂,采用开环共聚法合成了一系列相对分子质量和含氢量可控、相对分子质量分布较窄的含氢聚甲基硅氧烷(PDMS-co-PHMS)。研究了催化剂种类、反应温度、反应时间、催化剂用量、搅拌速度对产物相对分子质量、含氢量以及产率的影响,并通过正交试验对工艺条件进行优化,实现了一系列具有不同含氢比例的含氢聚甲基硅氧烷的可控合成;并利用红外光谱、核磁共振和凝胶渗透色谱对产物进行分析表征。结果表明,以强酸性离子交换树脂为催化剂,可控合成了相对分子质量为1.19×103~3.01×103的含氢聚甲基硅氧烷,最佳反应条件是反应温度为60℃,反应时间为12h,催化剂质量分数为1%,搅拌速度为400 r/min。     

含氢聚甲基硅氧烷的合成与表征EI北大核心CSCD

以八甲基环四硅氧烷(D4)、四甲基四氢环四硅氧烷(D4H)和六甲基二硅氧烷(MM)为原料,以强酸性离子交换树脂为催化剂,采用开环共聚法合成了一系列相对分子质量和含氢量可控、相对分子质量分布较窄的含氢聚甲基硅氧烷(PDMS-co-PHMS)。研究了催化剂种类、反应温度、反应时间、催化剂用量、搅拌速度对产物相对分子质量、含氢量以及产率的影响,并通过正交试验对工艺条件进行优化,实现了一系列具有不同含氢比例的含氢聚甲基硅氧烷的可控合成;并利用红外光谱、核磁共振和凝胶渗透色谱对产物进行分析表征。结果表明,以强酸性离子交换树脂为催化剂,可控合成了相对分子质量为1.19×103~3.01×103的含氢聚甲基硅氧烷,最佳反应条件是反应温度为60℃,反应时间为12h,催化剂质量分数为1%,搅拌速度为400 r/min。     

非离子型三硅氧烷表面活性剂的合成及其界面性能

1,1,1,3,5,5,5-七甲基三硅氧烷和单烯丙基聚乙二醇甲基醚在氯铂酸催化下经硅氢加成反应合成出了非离子型三硅氧烷表面活性剂(NTS)。通过红外光谱IR确证了NTS的结构,并通过测定NTS水溶液的平衡表面张力研究了其表面活性。结果表明在NTS浓度为6.3×10-4mol.L-1时,可将水的表面张力降低至23.5mN.m-1。0.1%NTS(质量分数)水溶液在塑料薄膜上的瞬间接触角为33.9°,15s时的接触角为17.3°,而空白水在塑料薄膜上的瞬间接触角为69.9°,30s时的接触角为59.3°;0.1%NTS(质量分数)水溶液铺展面积是水的7.2倍。     

环氧-聚醚端基改性硅油合成与工艺研究

以烯丙基聚醚(F-6)、环氧氯丙烷、1,1,3,3-四甲基二硅氧烷为原料制得环氧基烯丙基聚醚二硅氧烷。在碱性条件下,八甲基环四硅氧烷(D4)开环缩合,与环氧基烯丙基聚醚二硅氧烷反应合成环氧-聚醚端基改性硅油。1 H-NMR表明成功合成目标产物,讨论了物料比、反应温度、反应时间和催化剂用量对产物性能的影响,确定最佳工艺:环氧基烯丙基聚醚二硅氧烷与D4质量配合比为1∶1,催化剂用量为0.7%(wt,质量分数),60℃,反应3h,制得的环氧-聚醚端基改性硅油,收率达到78%。     

新型功能性倍半硅氧烷的合成与表征

以三氯丙基三甲氧基硅烷、苯基三甲氧基硅烷为原料,在一定条件下合成了笼形八聚(三氯丙基)倍半硅氧烷和双层倍半硅氧烷。进一步与叠氮钠、冠醚等通过取代反应、点击反应等方法来合成多种功能性的倍半硅氧烷,它们在复合材料等领域将有很好的应用前景。利用1-核磁共振光谱、13-核磁共振光谱、29-Si核磁共振光谱、基质辅助激光解吸电离飞行时间质谱等手段,对它们的结构分别进行了表征。     

对-双(二甲基-羟基硅基)苯及其缩聚物的合成

以二甲基二氯硅烷及对二溴苯等为主要原料,经历三个反应步骤合成了对-双(二甲基-羟基硅基)苯, 所有中间产物的分子结构均用1H-NMR确证.首次采用辛酸己胺作催化剂,将对-双(二甲基-羟基硅基)苯进行缩聚,获得了聚四甲基对硅亚苯基硅氧烷;研究了聚合时间以及催化剂用量对聚合物特性粘数的影响,并用1H-NMR及X射线衍射对聚合物进行了表征。     

聚醚改性三硅氧烷的合成

以不饱和聚醚和含氢硅油为原料,氯铂酸作催化剂,异丙醇为溶剂,通过硅氢加成反应合成出聚醚改性三硅氧烷.通过控制反应物配比、反应温度、时间和催化剂用量,研究了反应的较优反应条件:聚醚中的C=C双键与含氢硅油中的Si-H键物质的量之比为1.1:1.0,反应温度75℃,反应时间5.0h,催化剂用量与含氢硅油中Si-H键物质的量之比为5.0×10-5:1.     

氨丙基三硅氧烷的合成

以氨丙基二乙氧基甲基硅烷(SG-Si902)、六甲基二硅氧烷(MM)为原料,通过四甲基氢氧化铵((CH3)4NOH)催化合成了氨丙基三硅氧烷。考察了催化剂用量、反应时间、反应物的摩尔比、以及水含量对产物收率及纯度的影响,从而确定出反应的优化条件为:n(SG-Si902)∶n(MM)=1∶5,催化剂占总反应物的摩尔分数为0.45%,N2保护下搅拌反应2h,反应体系中尽可能减少水的含量,产物收率可达42.8%。并通过氢核磁共振(1HNMR)和气相色谱(GC)确证了产物的结构与纯度,其纯度可达99%。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。