Preparation and characterization of waterborne epoxy latexes and epoxy/(silica sol) composites

A series of waterborne epoxy latexes was synthesized, and epoxy/(silica sol) composite latexes were prepared. The effects of functional monomer methacrylic acid (MAA) and silica sol on the latex particle size, morphology, and stability were investigated. With increasing amounts of MAA, the conversion rate increased, the particle size reduced, and the viscosity of the epoxy latexes increased. The epoxy latexes had storage stability and could be stored at room temperature for more than 6 months with a solid content variation of less than 1%. For the (silica sol)‐modified waterborne epoxy latexes, the effects of preparation techniques and silica sol content on the latexes and latex films were investigated. When the silica sol content increased, the particle size of the composite latexes decreased. The morphology investigation showed that when the silica sol content increased, the uneven surface level of the latex films was increased. The increase of elemental silica on the surface was in accord with the improvement of the water resistance of the composite latex films. The heat resistance of these films was improved as well, and their overall performance was better than that of the epoxy latex films. J. VINYL ADDIT. TECHNOL., 20:57–64, 2014. © 2014 Society of Plastics Engineers     

Association Study Identifying a New Susceptibility Gene (AUTS2) for Schizophrenia

Schizophrenia (SCZ) is a severe and debilitating mental disorder, and the specific genetic factors that underlie the risk for SCZ remain elusive. The autism susceptibility candidate 2 (AUTS2) gene has been reported to be associated with autism, suicide, alcohol consumption, and heroin dependence. We hypothesized that AUTS2 might be associated with SCZ. In the present study, three polymorphisms (rs6943555, rs7459368, and rs9886351) in the AUTS2 gene were genotyped in 410 patients with SCZ and 435 controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and forced PCR-RFLP methods. We detected an association between SCZ and the rs6943555 genotype distribution (odds ratio (OR) = 1.363, 95% confidence interval (CI): 0.848–2.191, p = 0.001). The association remained significant after adjusting for gender, and a significant effect (p = 0.001) was observed among the females. In the present study, rs6943555 was determined to be associated with female SCZ. Our results confirm previous reports which have suggested that rs6943555 might elucidate the pathogenesis of schizophrenia and play an important role in its etiology.     

Preparation of Lung-Targeting,Emodin-Loaded Polylactic Acid Microspheres and Their Properties

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) has been identified to have the potential to improve lung fibrosis and lung cancer. To avoid the liver and kidney toxicities and the fast metabolism of emodin, emodin-loaded polylactic acid microspheres (ED-PLA-MS) were prepared and their characteristics were studied. ED-PLA-MS were prepared by the organic phase dispersion-solvent diffusion method. By applying an orthogonal design, our results indicated that the optimal formulation was 12 mg/mL PLA, 0.5% gelatin, and an organic phase:glycerol ratio of 1:20. Using the optimal experimental conditions, the drug loading and encapsulation efficiencies were (19.0 ± 1.8)% and (62.2 ± 2.6)%, respectively. The average particle size was 9.7 ± 0.7 μm. In vitro studies indicated that the ED-PLA-MS demonstrated a well-sustained release efficacy. The microspheres delivered emodin, primarily to the lungs of mice, upon intravenous injection. It was also detected by microscopy that partial lung inflammation was observed in lung tissues and no pathological changes were found in other tissues of the ED-PLA-MS-treated animals. These results suggested that ED-PLA-MS are of potential value in treating lung diseases in animals.     

适用于地铁线路的嵌入式轨道结构方案研究

嵌入式轨道结构在缓解钢轨磨耗和减振降噪等方面表现优异,目前主要用于有轨电车线路。研究提出适用于地铁线路的连续支承无扣件嵌入式轨道结构系统,为地铁轨道结构的减振方案提供一种新选择。在总结分析嵌入式轨道结构型式基础上,结合地铁线路的特点,确定了地铁用嵌入式轨道结构的选型原则和具体要求,提出并比较分析了4种新式嵌入式轨道结构型式。类I型、类III型板式嵌入式轨道适宜于直线线路,钢槽扣结式嵌入式轨道因换轨方便更适用于曲线线路,附加槽式可用于因提高减振降噪要求而进行的既有线改造。嵌入式轨道结构应用于地铁线路具有安全可靠,平顺性高、稳定性强和修复性好等显著优点。     

隧道爆破下建筑结构局部应力响应及损伤研究

依托新红岩隧道工程,探究了隧道典型爆破地震波与砌体低阶与高阶模态之间的关系,研究了不同工况爆破振动下砌体结构不同构件上的应力响应。砌体结构局部构件上的内力响应远比位移响应要显著,并且与质点的振速约成正比。在峰值振速相同条件下,当隧道爆破振动主频较高时,引起建筑物高阶局部模态下的动力反应,竖向振动引起的结构局部构件上的应力较大;反之,爆破振动主频较低,引起建筑物的低阶整体模态的动力反应,水平振动(结构弱轴方向)引起结构局部构件上的应力较大。砌体结构上的门角、窗角等应力集中部位最容易受损开裂,其次是在峰值振速较高时,局部振动较大的女儿墙、中隔墙等部位及砖墙与混凝土接触的部位也可能受损开裂。     

Soldering of Zr-based bulk metallic glass and copper by Au-12Ge eutectic alloy

Zr-based bulk metallic glass and copper with different surface roughness were soldered using low temperature eutectic Au-12 Ge(wt%) solder on a thermomechanical simulator. The cross-sectional microstructures of the brazed joints were analyzed by scanning electron microscopy(SEM) and transmission electron microscope(TEM) in detail, and the compositional distribution along the interface was analyzed by energy-dispersive spectrometer(EDS). Results show that the surface roughness of base metals plays an important role in the quality of the brazed joint because the surface roughness can enlarge the effective contact area, which can improve the brazing surface quality between two materials. A moderate roughness of treated Zr-based metallic glass of 18 μm is shown to be the best for the soldering, while the surface roughness has a weak effect on the soldering behavior of Au-12 Ge solder on copper. After soldering, long-range diffusion of atoms occurs between the base metal and solder, and five distinct regions are formed at the joint region.     

基于线性回归和神经网络的金属陶瓷激光熔覆层形貌预测

目的研究激光熔覆关键工艺参数(激光功率、扫描速度、送粉速率)与单道熔覆层宏观形貌(宽度、高度、熔池深度)之间的数量关系,以实现对WC-Co50复合熔覆层形貌的预测,从而为牙轮钻头的修复提供参考。方法设计不同的实验参数,利用4k W光纤激光器在牙轮钻头钢15MnNi4Mo表面熔覆单道WC-Co50复合涂层。采用工业显微镜观察单道熔覆层的横截面宏观形貌,并测量其三维尺寸。在上述形貌参数的基础上,分别运用多元线性回归分析和人工神经网络方法,建立关键工艺参数与熔覆层宏观形貌之间的关系模型,并将实验结果与模型预测结果进行对比。结果总体来讲,神经网络对熔覆层形貌的预测结果更为精确,平均相对误差为5.3187%;多元线性回归分析预测的平均相对误差为6.0028%。分析表明,对熔覆层宽度的预测结果最精确,两种方法的平均相对误差仅为1.2999%;对高度及熔池深度的预测结果稍差,平均相对误差分别为8.0586%和7.6237%。结论两种预测方法都具有较高的精度,但神经网络法函数关系不明确,运算过程复杂,需要通过进一步的算法优化来提高预测精度。     

多房间建筑室内火灾数值模型的验证

介绍单层多房间建筑室内火灾数值模拟的验证研究。模型的计算值与Luo和Beck的实验结果进行了比较。为了考虑火灾的燃烧的过程，采用Laminar Flamelet方法。多房间建筑内热辐射的计算则使用DOM（discret ordinates method）方法。在验证工作中，最困难的工作是通风不良条件下火灾的模拟。由于在低含氧量的情况下，火焰的燃烧特性并没有得到很好的认识，因此对燃烧模型并没有引入任何的修改，以便保留处理燃烧过程方法的通用性以及便于检验Laminar Flamelet燃烧模型的能力。模拟结果与Luo和Beck的实验值能很好吻合。     

地区间货物运输量预测方法谱系

本文整理了近些年地区间(城市间)货物运输量预测方法的研究。论文分析了和旅客运输相比,地区间货物运输的特点,提出了货物运输需求量的预测在理论和方法上和客流需求量的预测有所不同的依据。将以往的地区间货运量预测模型按不同阶段做了分类整理。其次,根据物流的行为者将地区间货运量预测模型分为计量经济学模型、空间相互作用模型及网络模型等类型。较为详尽地分析了各类预测模型的特点。并结合我国物流业的发展现状,对货物运输量预测方法研究的发展方向进行了展望。     

圆梁山隧道在高水位条件下支护结构体系研究

采用围岩与结构共同变形的计算模式，优选出圆梁山隧道在高压涌水条件下的合理支护结构形式。通过对圆梁山隧道注浆加固圈单独承载稳定性分析，拟定出圆梁山隧道所需加固圈的最小尺寸为3m。通过对38种工况模型的弹塑性数值计算，找出了在满足相同结构安全度要求K=2．4条件下，随着注浆加固圈厚度增加，可相应减薄二次衬砌所需厚度的关系曲线。此外，研究结果还表明，提高注浆水平能较大程度地减弱支护结构参数。因此，改善注浆水平是有很大意义的。