好氧颗粒污泥等温吸附甾体雌激素

为了研究好氧颗粒污泥对甾体雌激素E1、E2、EE2的吸附作用,通过摇瓶试验考察了吸附平衡时间及在不同温度下的等温吸附过程,对该过程进行了Freundlich方程和Langmuir方程拟合分析,并采用SEM观察好氧颗粒污泥结构.实验结果表明,吸附40min后基本达到平衡;吸附量随着温度的升高而减少,在20℃时,E1、E2、EE2最大吸附量分别为60.98、58.82、82.64μg/g;吸附过程符合Freundlich方程和Langmuir方程,其相关系数R2分别为0.93~0.99和0.92~0.99;吸附后好氧颗粒污泥表面及内部均发生了变化.     

硫酸亚铁铵盐弱酸性体系电镀锌铁合金的研究

以硫酸亚铁铵盐和氯化锌为主盐的弱酸性体系电镀锌铁合金,镀液静置15d,仍稳定、无沉淀。研究了添加剂、电流密度、温度和pH对镀层的外观以及镀层组成的影响。结果表明,增加添加剂的用量,降低温度或者电流密度,会使镀层变得光亮。pH对镀层光亮度的影响有一个最佳范围为4．50．5。添加剂用量为15-17mL／L,温度为30oC,pH为4．5-5,电流密度为0．5—1．0A／dm‘时,镀层光亮且铁含量在0．2％__0．8％。SEM图显示,添加剂用量的增加使得镀层的结构更加紧密。     

水热温度对玻璃纤维增强HAp-CS涂层的影响

为了制备出结合强度较好的生物涂层,采用水热电泳法在碳/碳复合材料表面成功制备了玻璃微纤维增强的羟基磷灰石——壳聚糖(g(f)/HAp-CS)复合涂层,用x-射线衍射仪、透射电子显微镜、扫描电子显微镜、能谱分析仪、红外傅里叶变换分析仪等测试手段对涂层进行了测试和表征,主要研究了水热沉积温度对复合涂层中HAp晶相和涂层显微结构的影响以及HAp涂层的沉积动力学.结果表明:采用玻璃微纤维增强的HAp-CS涂层,致密性和均匀性有了很大提高,显著减少了复合涂层表面的裂纹;随着水热温度的升高,涂层中HAp的衍射峰逐渐增强,表面形貌得到了有效改善,涂层的致密性和均匀性显著提高;涂层的沉积速率随水热温度的升高而加快,其沉积活化能为14.63kJ/mol.     

天然与浸泡SH胶麦秸秆微结构指标的对比分析

利用扫描电子显微镜对天然、不同浸水时间、不同浸胶时间及浸胶后浸水不同时间麦秸秆的横断面的微结构进行观察,并采用Leica QWin5000图像处理系统对SEM照片进行了微结构参数的统计．对麦秸秆微结构孔隙的等效直径、平面孔隙率和面积比三个指标进行了定量对比分析．结果表明：天然麦秸秆组织疏松,具有较强的吸水性,浸水膨胀使其孔隙增大;SH胶可有效地渗入麦秸秆孔隙内,并附着在表面上,填充了孔隙,使孔隙面积减小;SH胶对麦秸秆的吸附和补强作用具有不可逆性,浸泡SH胶能有效地增强麦秸秆的抗水性能．     

企业家精神对企业动态核心能力影响的实证研究

以企业家精神和企业动态核心能力的测量维度研究为基础,提出二者影响关系的理论框架模型．通过对368家企业的深度访谈和问卷调查,运用结构方程模型方法对理论模型拟和度,企业家精神对企业动态核心能力影响的路径进行了实证研究．研究结果表明,企业家精神对企业核心能力存在显著、正向且直接的影响,为企业推动企业家精神的培育与企业核心能力的提升提供了相关建议．     

天然橡胶/顺丁橡胶并用硫化胶的力学破坏机理

用扫描电子显微镜对天然橡胶／顺丁橡胶并用硫化胶的力学破坏机理进行了研究，结果表明试验样拉伸疲劳破坏断面具有拉伸断裂和屈挠龟裂的双重特征。白炭黑和Ｓｉ６９的加入使硫化胶的屈挠疲劳初始裂口形式发生变化。热氧老化使试样的拉伸断裂由韧性向脆性转化。     

基于SEM的干湿循环蚀变花岗岩分形特征与力学特性演化规律

分形维数是对岩石裂隙、破碎程度和损伤等细观特征的定量描述,岩石的细观结构往往会对宏观强度特征产生较大的影响。为了研究干湿循环侵水对蚀变花岗岩细观特征的影响,基于电镜扫描(SEM)试验,得到了经历不同干湿循环次数的蚀变花岗岩的细观图像,并通过盒维数法计算得到各岩样的分形维数,建立基于分形维数的细观损伤演化方程;其次,通过室内单轴抗压强度和抗拉强度试验,获得不同干湿循环次数下蚀变花岗岩的力学特性。通过试验数据,得到了干湿循环次数及分形维数分别与岩石强度特性和弹性参数的关系。研究表明:岩石干湿循环次数的增加在宏观上表现为抗拉强度、单轴抗压强度以及弹性模量的减小;在细观上表现为分形维数的增大;泊松比不受此影响。分形维数将岩石细观特征量化、建立了细观和宏观的联系。研究结果可为衡量蚀变花岗岩强度特性的指标提供依据。     

Characterization of polyhydroxyalkanoates synthesized in activated sludge using three carbon sources

Polyhydroxyalkanoates(PHAs) were synthesized in activated sludge using three types of carbon sources (sodium acetate,sodium propionate and sodium butyrate), and their characterization were studied. It was shown that the content of PHA synthesized by microorganisms in activated sludge were different. The biggest synthetic amount up to 36.7% of VSS was obtained when sodium acetate was used as carbon source. The polymer yield was lower when using sodium propionate as the carbon source than when using others, with 25.1% of VSS, while resulted in an increase of hydroxyvalerate(HV) units produced. The structure and thermal properties of extracted biopolymers were analyzed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and themo-gravimetry (TG).     

Scanning electron microscopy of nerve fibers in human fetal cochlea

The cochleas of four human fetuses ranging 22–25 weeks gestation were studied by scanning electron microscopy (SEM) for the purpose of obtaining a better understanding of the nerve fiber arrangement in the human ear. After critical point drying, the specimens were dissected and the floor of the tunnel of Corti and the outer wall of Nuel's space were exposed for observation. Upper cochlear turns, especially the apical turn, seemed to be still immature. Observed nerve fibers were classified into three types:

• 1 Spiral fibers: Fibers traveling basalward and following the shape of the cochlea were found in both the tunnel of Corti and Nuel's space and believed to be the afferent nerves responsible for innervating the outer hair cells
• 2 Radial fibers: radiating outward from the osseous spiral lamina—one such radial fiber transversing high in the tunnel space (supposedly the efferent nerve servicing the outer hair cells), and another sort of radial fiber (found crossing the tunnel floor), the nature of which was uncertain.
• 3 Irregular fibers: Consisting of thin, randomly running fibers within the cochlea. The destination of these fibers was not determined, but possibly they represent transitory nerve branchings of afferent or more probably efferent nerves, which would later regress during maturation.

     

超细矿粉对混凝土界面区硫酸盐腐蚀的影响

为了研究骨料与水泥石界面区(ITZ)的组成及结构对混凝土抗硫酸盐腐蚀性能的影响,利用紫外分光光度计绘制了硫酸钠溶液浸泡混凝土试样的SO2-4浸入浓度/深度曲线,并辅以扫描电镜(SEM)和电子探针能谱(EDS)等对ITZ进行观测;同时利用XRD定量分析研究了混凝土本体相和界面相的水化产物富集的差异.结果表明:Ca(OH)2、钙矾石(AFt)等晶体富集于硫酸钠溶液浸泡后试样的ITZ,引起AFt二次结晶型的硫酸盐腐蚀破坏.在适量石膏的激发下,掺入超细矿粉(GGBS)可阻止AFt转变成单硫型水化硫铝酸钙(AFm),减少AFt二次结晶的生成,明显提高抗硫酸盐侵蚀能力,试样的同深度硫酸根浓度最低,抗硫酸盐侵蚀性能最好.