Dynamic voltage scaling based energy-minimized partial task offloading in fog networks

Wireless Networks - With the dynamic voltage scaling (DVS) technology, the terminal node (TN) can dynamically adjust its computational speed, thus providing a new way to save energy during task...     

高边坡分级开挖与支护方案研究

边坡失稳是外界各种因素的共同作用下,由局部小范围的变形逐渐延伸扩大最终演变为整体破坏的灾变过程,在此过程中,控制边坡变形的因素也是"动态"变化的.对未支护下的边坡进行多级开挖,分析不同开挖时步下的坡体稳定性及其变形,根据其计算结果对边坡进行分级支护,分析支护后的坡体稳定性及其变形.对比结果表明,采用及时支护方式开挖的边坡安全系数在开挖早期有所降低,但后期逐渐增加,支护后坡体各监测点的水平位移和竖直位移均小于未支护前.     

Effect of chlorination and fluorination of benzothiadiazole on the performance of polymer solar cells

In order to explore the effects of chlorine and fluorine on photophysical properties and the differences, in this work, we synthesized five new polymers, P1 – P5 , in which benzo[1,2-b:4,5-b]dithiophene as the electron donating and benzothiadiazole as electron withdrawing. Analysis of these five polymers showed that the introduction of Cl and F atoms can deeper the highest occupied molecular orbital of these polymers and enhance the absorption of light by the species, thereby improving V_oc and J_sc. Chlorination has a stronger ability to reduce energy levels and broaden the absorption spectrum compared to fluorination. Among them, P2 showed an efficiency of 4.08% with J_sc of 11.28 mA/cm², V_oc of 0.79 V, and fill factor (FF) of 0.45. Since chlorination is easier than fluorination in terms of synthesis, it is advantageous for practical applications. Therefore, we think that chlorination should not be ignored when designing high efficiency photovoltaic materials, especially when their fluorinated counterparts have proven to have good properties.     

长短桩复合地基力学性状的现场试验

长短桩复合地基是近年来逐渐兴起的一种新的复合地基形式,但理论研究和实践仍不完善,需要进行更深入的探讨。通过长短桩复合地基的现场试验,对在刚柔两种基础形式下的长短桩复合地基的沉降变形、桩顶和桩间土的应力、桩土荷载分担比及桩土应力比随荷载变化的规律进行对比分析。研究成果可为长短桩复合地基理论研究和优化设计提供有益的参考。     

微机械槽板结构空气压膜阻尼的修正雷诺方程

推导出了一个适用于槽板结构压膜空气阻尼的微分方程.该方程与传统雷诺方程的区别是在雷诺方程的左边增加了一个用以表示气体从槽流出所引起的阻尼效应的修正项,并考虑了槽中有限气流通道长度的端头修正.在适当的边界条件下,利用此方程可以求解槽板压膜阻尼的压强分布、阻尼力和阻尼力系数.该槽板结构压膜空气阻尼的微分方程对槽板的厚度和横向尺度没有限制,为分析有限尺寸和有限厚度槽板的压膜空气阻尼提供了一个有用的方法.     

物联网柔性电子设备的无线电能传输技术研究

分析了物联网柔性电子技术的实际应用需求及存在的能源供给问题,提出可采用无线传能技术解决能源供给问题。目前对柔性电子系统中无线电能传输技术的研究主要集中在设计高性能的柔性天线和实现特定应用场景下的柔性系统无线充电功能。无线电能传输技术可以很好地匹配柔性电子设备的能源供给需求,是未来柔性电子设备供能的优选方式。在今后的技术发展中可从柔性设备制造工艺、柔性新材料、柔性无线传能装置的能量传递效率等方面进行突破。     

Investigation of Nd3+ incorporation in Ce-rhabdophane: Insight from structural flexibility and occupation mechanism

LnPO₄ · 0.667H₂O rhabdophane has been considered as a potential material for the precipitation of actinides from radioactive waste liquid, owing to its outstanding characteristics of high actinide bearing and easy synthesis in acid solutions. However, a comprehensive understanding of the actinide occupation and the precipitation response of rhabdophane to remove actinides has yet to be established. In this study, the effect of ions concentration and pH values on the detailed precipitation reaction of Ce_xNd_1-xPO₄ · 0.667H₂O rhabdophane in acid solutions are systematically investigated. Some specific issues such as structural distortion and flexibility, and occupation mechanism are discussed by combining with experiments and density functional theory (DFT) calculation. The results reveal that ions concentration and pH values have a significant impact on the crystallization nucleation step before 12 h. The obtained removal rate of Nd³⁺ is more than 99% in pH 1–5 solutions with the ions concentration of 0.05–0.1 mol/L. Moreover, incorporating Nd in CePO₄ · 0.667H₂O rhabdophane will easily result in the lattice distortion in b-axis. DFT calculation and X-ray photoelectron spectroscopy (XPS) results reveal that Nd is preferentially incorporated in nonhydrated site to form a weaker binding energy of NdO₈ polyhedron.     

Microporous gel electrolyte for quasi‐solid‐state dye‐sensitized solar cell

The extension of electrocatalytic reaction of I^?/I₃^? from counter electrode/gel electrolyte interface to gel electrolyte can significantly enhance the redox kinetics and therefore conversion efficiency of dye‐sensitized solar cells. Microporous gel electrolyte from polypyrrole integrated poly(hydroxyethyl methacrylate/cetytrimethylammonium bromide) [PPy‐integrated poly (HEMA/CTAB)] is successfully synthesized by in‐situ polymerization of pyrrole monomers in three‐dimensional framework of porous poly(HEMA/CTAB) matrix. An ionic conductivity of 12.72 mS cm^?1 and activation energy of 8.65 kJ mol^?1 are obtained from PPy‐integrated poly(HEMA/CTAB) gel electrolyte. Tafel polarization and electrochemical impedance spectroscopy are employed to characterize the electrocatalytic behaviors of the gel electrolytes. The resultant quasi‐solid‐state dye‐sensitized solar cell shows a light‐to‐electrical conversion efficiency of 6.68%. POLYM. ENG. SCI., 54:2531–2535, 2014. © 2013 Society of Plastics Engineers     

Dieterici气体对比态形式的转换温度

运用对比态形式的Dieterici状态方程,分析和导出焦-汤效应的对比转换温度与对比压强关系式,并且通过Matlab软件绘制Dieterici方程在不同温度指数的对比转换曲线,将其与Miller方程的对比转换曲线进行比较分析。     

不同类型石英玻璃的振动能量损耗特性对比分析

石英玻璃相对于金属、晶体、陶瓷等大多数固体材料具有更小的机械振动能量损耗,是许多精密测量器件的首选材料。本文测试对比了四种类型(Ⅰ类、Ⅱ类、Ⅲ类和Ⅳ类)石英玻璃的振动能量损耗特性,从材料化学组分和结构缺陷方面分析了石英玻璃本征损耗的影响因素及作用机理。结果表明:Ⅰ类和Ⅱ类石英玻璃的本征损耗显著大于Ⅲ类和Ⅳ类石英玻璃,主要是由金属杂质含量高和气泡等级低造成的;羟基含量不是影响石英玻璃本征损耗的主要因素;表面损耗是石英玻璃器件振动能量损耗的主要来源之一,可以通过湿法刻蚀消除。