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991.
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993.
为了研究GFRP/钢绞线复合筋混凝土梁的开裂性能,设计了5根GFRP/钢绞线复合筋混凝土梁试件,并对混凝土梁试件进行三分点静载试验研究,试验变量为混凝土梁截面尺寸和混凝土保护层厚度.在系统分析试验数据的基础上,提出GFRP/钢绞线复合筋混凝土梁抗裂承载力与最大裂缝宽度的计算方法,并给出使用荷载作用下的裂缝宽度限值. 相似文献
994.
为提高铝合金材料在高温下的使用性能,采用等离子电解法在锆盐体系和锆盐-钇盐复合体系中于铝硅合金表面制备了陶瓷层.分析了电解液浓度及成分对起弧电压、膜层厚度、组织及隔热温度的影响.研究结果表明:两种电解液体系中随电解液浓度的增大,起弧电压降低,陶瓷层厚度和隔热温度先增大后减小.与锆盐体系相比,锆盐-钇盐体系中起弧电压显著降低,膜层厚度与隔热温度提高.锆盐体系陶瓷层中生成了常温下稳定的t-ZrO2,锆盐-钇盐体系涂层中则生成了立方相的c-Y0.15Zr0.85O1.93.制备的两种陶瓷膜层与传统的硅酸盐膜层相比,其表面孔洞较少,锆盐-钇盐体系相对于锆盐体系其陶瓷层更加均匀、致密. 相似文献
995.
Electrochemical oxidation of the carbon nanotube (CNT) polarizable electrodes of electric double layer capacitors (EDLCs) was studied. It indicated that electrochemical oxidation elevated the available surface area of the electrodes and introduced some kinds of functional group on the CNT surfaces. The specific capacitances of the polarizable electrodes with organic electrolyte could be enhanced from 22.4 F g-1 to 78.2 F g-1 after electrolysis oxidization. The enhancement of the specific capacitance depends on the extent of electrochemical oxidation. Using acidic electrolyte for electrochemical oxidation has different effects on modifying the performances of the CNT polarizable electrodes compared to using basic electrolyte. 相似文献
996.
Huang JC 《Scanning》2012,34(4):264-270
This study investigates the surface conditions of silicon wafers with native oxide layers (NOL) or hydrogen passivated layers (HPL) and how they influence the processes of nano-oxidation and wet etching. We also explore the combination of nano-oxidation and wet etching processes to produce nanostructures. Experimental results reveal that the surface conditions of silicon wafers have a considerable impact on the results of nano-oxidation when combined with wet etching. The height and width of oxides on NOL samples exceeded the dimensions of oxides on HPL samples, and this difference became increasingly evident with an increase in applied bias voltage. The height of oxidized nanolines on the HPL sample increased after wet etching; however, the width of the lines increased only marginally. After wet etching, the height and width of oxides on the NOL were more than two times greater than those on the HPL. Increasing the applied bias voltage during nano-oxidation on NOL samples increased both the height and width of the oxides. After wet etching however, the increase in bias voltage appeared to have little effect on the height of oxidized nanolines, but the width of oxidized lines increased. This study also discovered that the use of higher applied bias voltages on NOL samples followed by wet etching results in nanostructures with a section profile closely resembling a curved surface. The use of this technique enabled researchers to create molds in the shape of a silicon nanolens array and an elegantly shaped nanoscale complex structures mold. 相似文献
997.
998.
This paper describes the results of a summative evaluation conducted to explore the usability and acceptability of an automated telephone-based technology, designed and developed as a screening tool for mental health disorders in the workplace. The system screens employees for symptoms and subsequently provides educational information and referrals to improve mental health and enhance productivity. The qualitative evaluation was a sub-study of a larger randomized controlled trial (RCT). We conducted in-depth interviews with 15 individuals who participated in the RCT and had used the system. A phenomenological theoretical framework was utilized to analyze the narrative data. Results indicated that participants had mostly positive experience with the system and perceived it as a confidential program that allowed them to reflect on their symptoms without inhibition, fear of judgment or embarrassment. We also learned that asking mere questions about mental health symptoms can be a positive, instructive and possibly a restorative experience. There is a likelihood that for many participants, exposure to questions about their emotional and mental distress validated their feelings about their symptoms and was sufficiently compelling to promote help-seeking behavior. This evaluation study demonstrates that computers can be utilized in the workplace as effective screening and educational tools to improve employees’ mental health. 相似文献
999.
Previous findings suggested that banner ads have little or no impact on perceptual behavior and memory performance in search tasks, but only in browsing paradigms. This assumption is not supported by the present eye-tracking study. It investigates whether task-related selective attention is disrupted depending on the animation intensity of banner ads when users are in a search mode as well as the impact of banner animation on perceptual and memory performance. 相似文献
1000.
Sexually transmitted infections (STIs) continue to pose a threat to the public health in the United States. Many sexual behaviors increase an individual’s risk of STI contraction. Chief among these are having unprotected sex, having sex with multiple partners, and either paying for sex or having sex for pay. The present study used General Social Survey (GSS) data from 2000, 2002, and 2004 to explore the association between exposure to internet pornography and these STI risk behaviors among adult US males. After controlling for demographic and individual difference covariates, internet pornography consumption was positively associated with having sex with multiple partners, engaging in paid sex, and having had extramarital sex. Internet pornography consumption was unrelated to having unprotected sex. Subsequent GSSs have not asked participants about exposure to internet pornography. As the GSS is the only ongoing, full-probability, national survey assessing social beliefs and behaviors, the present report provides unique insight into the risky sexual behavior patterns of adult male internet pornography consumers in the United States. 相似文献