球磨时间对模拟飞灰中汞的机械化学稳定化影响

为探明球磨时间对飞灰中汞稳定性的影响,采用全方位行星式球磨机对模拟飞灰中的汞进行机械化学稳定化处理,通过毒性浸出测试评价汞稳定性.利用比表面积分析、扫描电子显微镜、X射线光电子能谱等分析手段对汞稳定化前后的样品进行表征.结果 表明,未添加S条件下,球磨可提高汞稳定性,归因于粒径与结晶度降低、反应活性增强,发达的孔隙结构...     

基于压力-状态-响应模型的历史街区防火韧性评估体系构建及应用——以福州市三坊七巷为例

在韧性城市的建设背景下,历史街区的防火韧性被解释为:在降低火灾风险和维持自身稳定性的同时具备抵抗力、适应力和恢复力.基于"压力-状态-响应"模型,结合专家打分法和层次分析法,构建由33个指标层组成的历史街区防火韧性评估体系.以福州市三坊七巷为例开展的评估结果表明,该街区压力层潜在的刺激性较大,状态层暴露出的敏感性较高,但同时响应层表现出的适应性较强.针对研究结果,分别从建筑性能、街区空间和管理机制3个方面提出优化策略.研究成果既可为定量评估历史街区的消防能力提供参考依据,亦可为推进中国历史街区的保护和开发提供决策支持.     

Doppler radar by using single multicarrier pulse based on optical fibre delay lines

The proposed Doppler measurement technique shows that the Doppler measurements can be accomplished by a single pulse with multiple frequency components through optical fibre delay lines. Range and velocity ambiguity can be removed, and the velocity resolution can be improved dramatically by using long optical fibre delay lines. Furthermore, the velocity resolution can be modified by adjusting the length of optical fibre delay lines. In addition, the proposed radar can achieve high range resolution by using a single wideband pulse. As a result, the new approach can improve radar performance significantly.     

高强预应力管桩PHC桩在太原地区的应用分析

文章论述了高强预应力管桩PHC桩在太原地区的应用特点和适用条件及需要注意的事项,并通过举例说明高强预应力管桩PHC桩的经济效益比混凝土灌注桩明显的多.     

Metal ion-binding properties of wild-type and mutant D37K of ciliate Euplotes octocarinatus centrin

Ciliate Euplotes octocarinatus centrin (EoCen) is an EF-hand calcium-binding protein closely related to the prototypical calcium sensor protein calmodulin. The first amino acid of the Ca²⁺-binding loops found in the EF-hand calcium-binding proteins is a highly conserved aspartic acid residue. The D37K mutant was produced to elucidate the metal binding role of the first aspartic acid of the EF-loop I of EoCen. Aromatic-sensitized Tb³⁺ fluorescence results indicated that the metal binding ability of loop I was lost due to the D37K mutation. Based on fluorescence titration curves of Lu₂-D37K, the conditional binding constants of the EoCen loop II were quantitatively found to be K _II = (1.61 ± 0.04) × 10⁵ L mol^?1 and K _II = (3.52 ± 0.08) × 10² L mol^?1 with Tb³⁺ and Ca²⁺, respectively. Using 2-p-toluidinylnaphthalene-6-sulfonate as a hydrophobic probe, exposure of the hydrophobic surface upon metal binding was found to be significantly reduced for the metal ion-saturated EoCen D37K mutant.     

Photoresponsive thin films containing an azobenzene derivative intercalated with a layered double hydroxide

Two kinds of optically transparent thin films with photochromic properties have been fabricated based on co-intercalation of 4-(4-anilinophenylazo)benzenesulfonate (AO5) and sodium dodecylbenzene sulfonate (SDS) into the galleries of a ZnAl layered double hydroxide (LDH) by two synthetic methods: solvent evaporation and in situ crystallization. The two films possess LDH crystallites in different orientations relative to the substrates depending on their fabrication method: horizontal and vertical. The relationship between the photochromic behavior of the interlayer chromophore and the orientation of the LDH crystallites is studied thoroughly. The orientation of the LDH crystallite influences the photochromic behavior of the films. The films exhibited different absorption and wettability characteristics, providing the potential for application of dye-LDH films as photochromic materials and light sensitive switches.     

Transparent organic light-emitting diodes based on Cs<Subscript>2</Subscript>CO<Subscript>3</Subscript>:Ag/Ag composite cathode

The transparent organic light-emitting diodes (TOLEDs) based on Cs 2 CO 3:Ag/Ag composite cathode are reported in this paper.They show higher efficiency and better stability than the control devices with the Cs 2 CO 3 /Ag cathode.The devices are highly transparent,and show total efficiencies from both sides of the devices comparable with conventional bottom-emitting devices.The electroluminescence (EL) spectrum from the cathode side of the device is closer to the photoluminescence (PL) spectrum of the light...     

带槽叠合梁极限承载力分析研究

以带槽混凝土叠合梁为研究对象,对其极限承载力进行了力学分析.研究表明:带槽叠合梁极限承载力与一般平板式叠合梁极限承载力计算方法类似,计算时应按照截面面积和惯性矩相等的原则进行截面转化,将截面转化为两端为倒T形,跨中为工字型的梁截面,便于设计计算.     

高校学生评教:基于教学质量保障的思考

学生评教作为教学质量保障的重要组成部分,体现了"以学生为主体"的现代教育理念,在提高教学质量上也起到了重要作用;然而,学生评教在实践中因存在诸多问题而倍受质疑。学生评教制度作为高校教学质量保障体系还需要不断完善,只有这样才更有利于促进教学质量的提高。     

GPS/VISNAV integrated relative navigation and attitude determination system for ultra-close spacecraft formation flying

For the improvement of accuracy and better faulttolerant performance, a global position system (GPS)/vision navigation (VISNAV) integrated relative navigation and attitude determination approach is presented for ultra-close spacecraft formation flying. Onboard GPS and VISNAV system are adopted and a federal Kalman filter architecture is used for the total navigation system design. Simulation results indicate that the integrated system can provide a total improvement of relative navigation and attitude estimation performance in accuracy and fault-tolerance.