Si/C/N纳米粉体在水-氨基甲酸乙酯溶剂中分散行为的研究

Si/C/N纳米粉体具有活性高、难以在水中进行分散的特点.为改善其分散性,本论文采用添加表面活性剂、机械搅拌、调节pH值等手段,对Si/C/N纳米粉体在水-氨基甲酸乙酯溶剂中的分散行为进行了研究.结果表明:经过相应工艺处理后的Si/C/N悬浮液中纳米粉体的平均粒度可达200nm左右,其中98.3%的颗粒平均粒度达到75.9nm,稳定时间超过一个月.     

Effect of Polyvinyl Alcohol with a Thiol End Group on the Properties of Polyacrylic Dispersions and Spray-dried Powder

The emulsion polymerization of highly shear-stable copolymer dispersions of methyl methacrylate and butyl acrylate were carried out using poly （vinyl alcohol） with a thiol end group （PVA-SH） as protective colloid. The dispersions can be transformed into corresponding redispersible powder via a spray dryingcooling process. On-line FT-IR monitoring shows that grafting polymer of PVA-g-PMMA was formed mainly at the stage-1 of the emulsion polymerization. TEM images show, the PVA-SH shell was fragmentary when adding SDS at initial stage and integrated when adding at particle growing or final stage. The particle size turns to be smaller when delayed adding SDS surfactant. Triethanolamine, a co-regulator of PVA-SH, controlled the M to 50 000-70 000 and reduced the PDI to 1.5-1.7. The acrylic dispersions with 0.8wt%-1.5wt% PVA-SH1 can be spray-dried into super dispersible polymer powder （SDPP）, which can easily disperse in water and form recon- stituted dispersions with an average particle size smaller than 1 micron.     

沥青混合料旋转压实效果的数字图像分析

针对旋转压实法，利用不同压实功作用成型试件模拟压实过程，采用数字图像处理技术，研究沥青混合料的压实成型特性，提出了以集料颗粒的取向特性描述沥青混合料的稳定性，以集料颗粒的分布特性来反映混合料的密实程度，定义了集料颗粒主轴方向、沥青砂胶膜厚及颗粒面积比等参数来进行评价。实验表明效果良好。     

固体粒子分散体系润滑剂对接触疲劳前期影响的研究

针对固体粒子分散体系润滑剂的粒子大小的不同，提出了赫兹压力下降与滑膜高粘吸附两种物理模型，并分析了两种单分散介质的润滑剂对接触疲劳前期（即裂纹萌生之前）的影响结果，还解释了疲劳试验结果的某些现象。     

C_(60)-甲苯分散体系流变性质的研究

通过Ｃ６０－甲苯溶液的粘度、ＵＶ－ｖｉｓ吸收光谱的测定,求得溶剂化层厚度为２．１８ｎｍ,Ｃ６０在甲苯溶液中发生红移,特征峰λｍａｘ＝３３６．１ｎｍ。并求得室温扩散系数Ｄ＝５．５×１０－１０ｍ２·ｓ－１,较某些低分子小一个数量级,这些实验结果表明甲苯对Ｃ６０分子有明显的溶剂化作用。     

纳米粒子修饰TiO_2薄膜的制备及其光致亲水性能

实验通过调节TiO2前驱体溶胶中水-醇的体积比（Vw∶Ve）及涂膜时的环境温度,制备了一系列表面由不同尺寸粒子修饰的TiO2薄膜。薄膜表面的TiO2粒子沿袭了溶胶中分散粒子的特征。一方面,随着溶胶中Vw∶Ve的增大,分散质点粒子的尺寸增大,而另一方面,随着温度的升高,溶胶中分散质点粒子因溶解度增大,尺寸呈现减小趋势。因此通过调节Vw∶Ve及涂膜时候的环境温度,可制备所期望尺寸粒子修饰的TiO2薄膜。在Vw∶Ve=10∶5、涂膜温度40℃的条件下制备的TiO2薄膜显示了最佳的光致亲水性、自清洁效果及光催化活性。     

四探针法测聚苯胺膜电导率的探讨

采用分散聚合反应体系,原位沉积制备聚苯胺/聚酰亚胺/聚苯胺(PANI/PI/PANI)导电复合膜。根据四探针法测量薄片电导率时对厚度的修正理论,推导出厚度在数字式四探针测量仪厚度修正范围之外的聚苯胺膜电导率测试值的"厚度修正"方法。为验证该厚度修正方法的准确性,将所制备的同等电化学性质的聚苯胺颗粒进行压片,制备出厚度在现有测量仪厚度修正范围之内的聚苯胺薄片,并用四探针法测其电导率。对比2种方法所测的聚苯胺电导率,结果表明,2种方法测得的电导率数量级一致,说明该厚度修正方法是相对准确的。     

灵武煤制水煤浆颗粒级配研究

根据颗粒堆积模型,探讨了粒度分布对水煤浆成浆性能的影响.用GZS-1型标准振筛机将煤样筛分成60～140目、140～200目及200目以上3种.采用干法制浆,配制了理论质量分数为65%的浆体,分别考查了各区间粒度组分数对浆体成浆性能的影响规律.结果表明,200目以上颗粒质量分数为30%,140～200目颗粒质量分数为30%,60～140目颗粒质量分数为40%时制得的水煤浆黏度最低,为497.0 mPa.s.     

交联透明质酸凝胶薄膜的制备和性能表征

用己二酸二酰肼（ADH）对透明质酸（HA）进行化学修饰,研究不同交联程度HA．ADH的理化性质．用溶剂挥发法制备出HA—ADH薄膜．经差示扫描量热仪DSC分析得知,交联后产物的微观结构发生了明显改变．该薄膜在缓冲溶液中发生溶胀,有很强的吸水能力,扫描电镜SEM图显示溶胀的薄膜呈现高度多孔的网状结构．粘度法测定HA和HA-ADH的特性粘数[η]分别为14．69dL／g和20．21dL／g．改性后HA-ADH薄膜的溶解性比HA薄膜的溶解性能明显降低,可使得高聚物在体内的存留时间增长．     

Effect of polycarboxylate-type superplasticizer on the paste fluidity based on the water film thickness of flocs

The excess water film theory and the properties of flocs are integrated to examine the effect of the polycarboxylate-type superplasticizer on the paste fluidity.The theory states that excess water can surround the flocs rather than the particles and that the cell consists of a floc and a superficial water film.Experiments on limestone powder pastes were conducted to verify the theory.The superplasticizer dosage(sp%)and the water–powder ratio by volume(Vw/Vp)were systematically varied.A sedimentation balance method was used to measure the size distribution of the flocs in the limestone powder pastes.The water film thickness(WFT)of flocs was then calculated and shown to determine the paste fluidity.Based on this WFT of flocs,the effect of the sp on the paste fluidity was determined and then compared with the effect of water.     

混合溶剂对预聚体法聚氨酯分散液性能的影响

将丙酮(AC)、N,N-二甲基甲酰胺(DMF)和N-甲基吡咯烷酮(NMP)中的任意两种按不同比例进行混合,作为有机助溶剂,以甲苯二异氰酸酯(TDI),聚己内酯二元醇(PCL)和二羟甲基丙酸(DMPA)为反应原料,通过预聚体法制备了系列水性聚氨酯分散液.并研究了混合溶剂对分散液粒径、胶膜机械性能和吸水率的影响,又将聚氨酯分散液用作纸张表面施胶剂,分析了其对纸张性能的影响.实验结果表明:由67%DMF和33%AC混合溶剂所制备的分散液平均粒径最小;以100%AC所制胶膜的拉伸强度最大,50%AC和50%NMP混合溶剂所制胶膜的断裂伸长率最大;由100%NMP所制胶膜的吸水率最低;由50%NMP和50%DMF所制PU1施胶纸的湿强度最大;由50%AC和50%DMF所制PU2施胶纸的环压指数最高;由100%NMP所制PU11施胶纸的耐折度最高.     

Particle inertia effect on sediment dispersion in turbulent open-channel flows

Particle inertia effect plays a significant role in sediment dispersion which has not been fully elucidated. In this paper, the profound effect of particle inertia on the sediment dispersion was analyzed. The theoretical expression for the drift velocity based on the two-phase mixture theory in turbulent open channels is firstly introduced. The influence of particle inertia on sediment dispersion was investigated through three different aspects including vertical dispersion, motion, and flux properties based on the drift velocity. Results show that the dispersion of suspended sediment in turbulent open-channel flows is affected by three major processes including turbulence of water sediment mixtures, particle random motion, and collisions among particles, of which the contributions of particle turbulence and collisions to the sediment dispersion are remarkable for particles of high inertia. With respect to the vertical mean velocity and sediment flux, it shows that the predictive results agree well with the measurements when the term of particle inertia is considered. As a result, particle inertia considerably affects the behavior of suspended sediment. In particular, the influence of inertia must be accounted for in circumstances of flows laden with high-inertia particles.     

化学机械研抛过程流体和磨粒分布特性仿真

为深入理解化学机械抛光过程中的摩擦磨损机理,仿真研究了不同工况对抛光作用的影响规律.建立考虑多相流和离散相的三维CFD模型,研究不同工况下晶片和抛光垫间抛光液的速度和压力分布以及抛光磨粒的分布规律.结果表明:膜厚越小,抛光垫和晶片的转速越大,磨粒的分布密度越小.对流体速度和压力分布规律以及磨粒分布特性进行仿真分析,研究抛光过程中磨粒对晶片表面的动压作用过程.用疲劳断裂能量守恒理论,建立可定量分析各种工况下材料去除率的预测模型,采用Matlab软件对去除率模型进行仿真计算,得到不同工况下碳化硅晶片的去除率曲线.结果表明,抛光垫转速越大,膜厚越小,材料去除率越大,但去除率随着抛光的进行呈现减小的趋势.相比抛光垫转速对去除率的影响,膜厚对去除率的影响较小.     

中和剂用量和种类对双组份水性聚氨酯性能的影响

采用预聚体分散法,以甲苯二异氰酸酯(TDI)、聚碳酸酯二醇(PCDL)、二羟甲基丙酸(DMPA)、三羟甲基丙烷(TMP)为基本原料,并分别以三乙胺、N,N-二甲基乙醇胺、二乙醇胺、三乙醇胺为中和剂合成了双组份水性聚氨酯(WPU)乳液,并对WPU乳液进行固化获得胶膜,研究中和度及中和剂种类对双组份水性聚氨酯乳液外观、乳液粒径、胶膜的力学性能和吸水率的影响.结果表明:随着中和度的增加,乳液的粒径先增大后减小,双组份胶膜的断裂强度先减小后增大,断裂伸长率先增大后减小,吸水率则逐渐增大;随着中和剂种类的变化,中和剂所带羟基数的增加,双组份胶膜的断裂强度逐渐增大到29.08 MPa,断裂伸长率逐渐减小到9.2%,吸水率逐渐减小至1.8%.     

不同工艺参数对金刚石薄膜齿轮制备的影响

金刚石薄膜是最具潜力的微机械结构功能材料之一,但其极高的硬度和化学稳定性使其难以被加工成型。本文采用反应离子刻蚀方法对金刚石薄膜进行了微齿轮结构的制作研究,制作出了厚度为5gin,模数为0．003的金刚石薄膜齿轮。实验结果表明,镍钛合金薄膜和光刻胶层作为金刚石薄膜刻蚀掩模,可以获得表面平滑、轮廓清晰、侧壁陡直的金刚石薄膜图形;O2及与Ar的混合气体对佥刚石薄膜图形化的刻蚀主要工艺参数如射频功率、工作气压、气体流量及反应气体成分等均对刻蚀速率和刻蚀界面形貌产生不同程度的影响。刻蚀中,当工作气压12Pa及气体流量50sccm稳定时,射频功率与刻蚀速率呈线性变化,但射频功率过高（大于135W）则掩模刻蚀生成物沉积在金刚石薄膜表面而发黑;对于给定的工艺条件下,金刚石薄膜的刻蚀速率并不强烈依赖于混合气体中氧气的含量。     

壁湍流中喷发和扫掠对颗粒离散的影响

近壁湍流中的拟序结构：喷发（ejection）和扫掠（sweep）,对壁附近颗粒的扩散输运起着重要作用。本文首先采用直接数值模拟（DNS）方法得到槽道湍流（雷诺数Rer=Uδ／v＝80）的速度场,然后追踪颗粒群中每个颗粒的轨迹,最后详细分析喷发／扫掠事件对颗粒群离散行为的统计特征。模拟结果表明,流向和展向的粒子离散,在扩散初期来自于扫掠事件中的粒子离散大于来自于喷发事件中的粒子离散。当扩散时间超过数倍拉格朗日积分尺度后,开始时刻处于喷发或扫掠的粒子运动规律没有明显的不同,也就是说这些粒子几乎已经失去初始记忆。     

Rapid nanopatterning technique based on monolayer silica nanosphere close-packing by spin coating

Nanoparticles monolayer formation by spin coating is considered to be a simple, fast and inexpensive nanopatterning technique. However, the parameters that govern the overall growth process in this technique are not completely quantified and techniques for the controlled and continuous growth of close packed monolayer particle arrays without defects need to be developed. In this paper, an ordered particle array formation process is analyzed theoretically, employing material flux balance and particle- subjected forces balance, based on the film thickness model of spin coating and evaporation rate law. A series of experiments were conducted using silica particle suspensions with various particle volume fractions and different spin speeds. The results show that the spin speed should match the particle volume fraction to meet the requirements of material flux and particles movement in order to obtain a close packed monolayer film. The formation mechanism of fabrication defects involving particle agglomeration and uncontrollable voids were analyzed qualitatively based on crystal growth theory, and validation experiments were performed. The formation of highly uniform close-packed monolayer films was demonstrated and the condition requirements for achieving monolayer nanoparticles array with good quality presented.     

W/W型PAM-MMT乳液的制备及性能研究

为了提高以明胶为稳定剂分散聚合制备的聚丙烯酰胺“水包水”（W/W型PAM）乳液的絮凝性能，首先，采用阳离子单体甲基丙烯酰氧乙基三甲基氯化铵（methacrylatoethyl trimethyl ammonium chloride, DMC）对钠基蒙脱土（sodium-montmorillonite, Na-MMT）进行插层改性制备有机蒙脱土（organic montmorillonite, OMMT），通过X射线衍射（X-ray diffraction, XRD）测试得到插层改性后蒙脱土的层间距由1.25 nm增加至1.43 nm，说明DMC单体已经成功插层进入蒙脱土片层。然后，将OMMT引入以明胶为稳定剂的W/W型PAM乳液的体系中，以制备W/W型PAM-MMT乳液。通过透射电镜（transmission electron microscope, TEM）乳液微观形貌进行观察，得到乳液结构是由以蒙脱土颗粒为“交联点”的聚丙烯酰胺高分子网络和W/W型PAM乳液的混合体。研究了OMMT用量、明胶浓度、体系pH值以及阳离子单体DMC添加比例对合成W/W型PAM-MMT乳液性能的影响规律。结果显示：在适宜条件下合成的乳液均具有较好的储存稳定性和在水中的再分散性。乳液的表观黏度和絮凝性能都与OMMT和明胶用量呈正相关性；当pH值在明胶等电点（isoelectric point，IEP）时，得到的乳液的表观黏度最低，絮凝效果最好；随着DMC单体用量比例增大，乳液表观黏度减小，高岭土悬浮液的絮凝效果先增大后减小。     

AN INVESTIGATION OF FACTORS AFFECTING THE VISCOSITY OF SUZHOU KAOLIN SUSPENSIONS

Factors affecting the viscosity of the concentrated kaolin suspensions of Suzhou kaolins were studied. Experiments were carried out to use different kinds of dispersants to reduce the viscosity of the concentrated kaolin suspensions. The results indicated that good effects on reducing the viscosity of the concentrated kaolin suspensions were achieved by using the dispersants prepared in this laboratory , especially the combination of dispersants D III plus D IV . The viscosity of the concentrated kaolin suspensions was reduced from greater than 10000 MPa ' s to less than 500 MPa s. Analytical tests indicated that in the presence of the dispersants the surface properties were the major factors affecting the viscosity. The action of the dispersants is to change the surface properties rather than the morphology and structure of the minerals in the kaolin ores. The addition of the dispersants increased the hydrophilicity of particle, surfaces and the electrostatic repulsion between particles, resulting in i     

薄膜蒸发器的测控系统

通过对薄膜蒸发器工艺、设备操作条件的分析,提出了真空和粘度二个控制系统。解决了原操作中质量不稳定的问题,提高了产品的质量。