完善工程量清单招标的几点思考

通过对现阶段工程量清单招标现状的分析，提出了从施工图审查阶段、招标资格预审、不同设计深度下如何完善工程量清单招标及工程景清单招标的风险控制等方面的改进设想。     

氟化硅氧烷改性环氧树脂的制备与性能

首先,以全氟(2-甲基-3-氧杂己基)氟化物(六氟环氧丙烷二聚体)和N-(β-氨乙基)-γ-氨丙基三甲氧基硅烷(KH792)为原料制备一种氟化硅氧烷,用FTIR和1HNMR表征其结构.然后,将氟化硅氧烷与聚醚胺共同固化环氧树脂DGEBA(双酚A型二缩水甘油醚),测试了改性环氧树脂复合材料的性能.结果表明,与未改性环氧树脂相比,加入氟化硅氧烷使含氟量1％(以DGEBA质量计)改性环氧树脂复合材料的表面静态水接触角由72.0°增至103.2°,表面能由(42.08±2.17)mN/m降至(20.55±1.45)mN/m,40 d吸水率由1.75％降至1.38％,有效提高了材料的疏水性;介电常数由3.83降低至3.63;材料热分解5％温度由339℃升高至347℃;拉伸及弯曲力学性能分别提高了8.5％及7.7％.含氟量为1％时,改性环氧树脂复合材料的综合性能最佳,差式量热扫描和动态力学性能测试结果表明,少量改性剂可以促进环氧树脂的固化反应,提高固化度和交联密度;当氟化硅氧烷添加量增加时,材料内部发生显著的微相分离并导致性能逐渐下降.     

边缘氢化石墨烯片层结构和光谱性质的密度泛函理论研究

以并3-6苯环为氢化石墨烯片层模型,采用量子化学密度泛函理论方法(DFT)在B3LYP/6-31G(d,p)水平上进行了几何结构全优化,讨论了分子结构、能量、前线分子轨道等性质的变化规律。在得到化合物基态稳定构型的基础上,运用含时密度泛函理论(TD-DFT)计算了电子吸收光谱的性质。计算结果显示边缘氢化石墨烯片层均为平面结构,线型扶手椅型结构能量最低,结构最稳定。随着石墨烯片层环数的增加HOMO轨道能量增加,LUMO轨道能量降低,能隙能量降低,最大吸收波长明显红移。     

折半查找算法在电子会议系统调试中的应用

关联性故障代表单元的查找定位是电子会议系统调试的关键环节。为了提高查找定位效率,提出了一种基于折半查找的快速定位算法。通过对电子会议系统中干线上的代表单元可靠度的分析,把代表单元的故障情况转化成随着代表单元数量动态变化的量化数据,构成一组有序的可靠度数据,将工程调试问题转化成数据分析问题,引入折半查找算法,设计高效准确定位故障代表单元的算法,并进行了算法效率分析。该方法操作简单,无需借助特殊工具即可应用于复杂环境下电子会议系统的现场调试。     

感光化学中的近代研究方法

主要介绍了近 2 0年来电子显微技术、波谱技术、核磁共振技术、微波光导测试技术和离子电导测试技术等在卤化银晶体和潜影生成过程研究中的应用。     

基于电子印刷工艺的薄膜热电偶研制

薄膜热电偶由于具有体积小、热容量小及响应速度快等优点成为近年来学者们研究的重点。薄膜制备常用的方法有射频溅射法、离子镀膜法以及直流脉冲磁控溅射法等,但这些方法操作设备复杂,制作时间长,效率低,成功率低且复现性差。用电子印刷工艺制备薄膜热电偶,将Au,Pt的溶液化微纳米材料印制在基板上,印刷成为Au-Pt薄膜热电偶,该方法操作方便快捷,对电极材料污染小。通过试验证明:采用电子印刷工艺制备的Au-Pt薄膜热电偶符合Au-Pt热电偶检定规程的要求,热电偶精度高,重复性和一致性好。     

电磁波干扰屏蔽塑料

屏蔽塑料是一种功能性高分子新型材料。用此种塑料制成的电子机器、仪器壳体,能有效地防止电磁波干扰造成的各种事故。国外公司推出的不同品种的屏蔽塑料,可供我国塑料的开发应用参考。     

黄腐酸结构、构象和聚集过程的分子模拟研究

自然界中广泛存在着的腐植物质(HS)有多种化学反应能力,诸如矿物质的风化、养分的生物有效利用和污染物的迁移等相关的生物地球化学反应能力。腐植物质的反应性取决于其官能团的化学特性与微观结构,同时又受到周围环境及介质组分的影响。为了更好地了解腐植物质在水、土壤中的结构、构象以及聚集过程,文中描述了以伯明翰东北部庙宇(TNB)的样本,按离子或非离子的黄腐酸分子结构建模研究的过程。该理论研究结果和黄腐酸的溶解度(偶极矩)、电子和振动光谱等一些实验研究的结果能很好的吻合。其中水分子的存在对静电有很大的稳定作用,并且随着离子化程度的增加,这种作用变得更强。在真空中,由于氢键和非键力相互作用增加,未离子化的聚集体比单体更稳定。因此,随着黄腐酸分子的离子化,聚集作用将不再发生。在溶液中,黄腐酸的浓度是聚集的关键因素。若当量浓度太低,含有两个黄腐酸的系统就不可能发生聚集,但是随着当量浓度的提高,系统中聚集体的数量也将上升,情况就发生改变。离子态是聚集的另一个关键因素。离子态的黄腐酸分子有着更高的负电荷,而这会增强能量势垒,阻碍由布朗运动引起的黄腐酸分子的相互接近。     

Effects of individuals' locus of control and computer self-efficacy on their e-learning acceptance in high-tech companies

High-tech companies encounter intense competition in today's global economy. With rapid changes in working environments, high-tech employees must learn quickly and effectively to solve difficult problems and increase their productivity. Many large high-tech companies have recently implemented electronic learning (e-learning) for employee training. However, e-learning systems are expensive and often underutilised. Therefore, understanding the factors associated with acceptance to e-learning are of priority concern. By integrating locus of control, computer self-efficacy and technology acceptance model (TAM) into one model, this study examines the feasibility of the extended TAM to explain employee acceptance of e-learning systems. Data were collected from 223 employees at five high-tech companies located in the Hsinchu Science Park, Taiwan. Analytical results indicate that locus of control had significant direct effects on perceived usefulness and perceived ease of use. Computer self-efficacy had significant direct effects on perceived ease of use and behavioural intention to use. Overall, analytical results provide strong support for using the extended TAM to explain user acceptance of e-learning systems. The research and practical implications of findings are discussed.     

Adaptive training interfaces for less-experienced,elderly users of electronic devices

A great number of complex electronic devices are now part of our everyday lives. While many of us learn to handle these products by trial and error; others, especially older users with little experience in using electronic devices, need support. In order to allow the user maximum flexibility in terms of learning time and location, a training programme is presented which is implemented as part of the software embedded in the product itself. Particular focus is placed on the effect of adaptive training on learning. In this study, the training versions differed in their ability to adjust their complexity to the user's experience (adaptive user interface complexity) and their capability to support the learner by prompting them during the learning process (adaptive training advice). The results show that the adjustment of complexity had a positive effect on users’ experience: elderly users who trained with an adaptive interface were more successful in learning to use a mobile phone. Adaptive training advice, however, was found to have no significant effects on learners’ success and reduced their self-efficacy. This work offers guidelines on how to design integrated training applications for electronic devices that successfully help elderly users with little prior experience.