Soil Erosion on a Slope without Vegetation： a Simulating Experiment on a Bare Land in Mt. Tanakami

0　IntroductionManystudieshavebeendoneonthesedimentdischargeinMt.Tanakami .Thosestudiesconcerntheamountofsedi mentsandfewdiscussionsabouttheprocessonly .Andthesedi mentyieldmechanismindevastatedslopeinMt.Tanakamiisnotfullyunderstood.Inordertorecordthewholeprocessofsoilero sionfromthebeginningofprecipitation ,totheendofsedimentmovement,asimulatingexperimentbyusingartificialrainiscon ducted .Basedonthisexperiment,andbyfurthercomparingwiththepreviousdataofsedimentsinthisarea,somebasicdataaboutc…     

锥柱式桩基础明挖基坑回填土回冻过程模型试验研究

结合工程实际,通过室内模型试验方法,研究锥柱式桩基础明挖基坑回填土在模拟实际环境温度条件下的回冻过程.结果表明,在模拟平均温度为-2.71℃的环境温度条件下,正温极值时刻表层土体融化深度约6.1 cm,回填土冻结深度随着冻融次数的增加而增厚,经历13次冻融循环,冻结层厚度达20.0 cm;桩基沿着水平向和纵向对回填土回冻过程产生影响,但其影响范围有限;土体和桩基与空气界面温度存在差异,桩基和空气界面处温度接近低温试验箱内空气温度,土体和空气界面处与空气温度差别较大,正温极值状态,空气温度高于土表温度5.0℃,负温极值状态,空气温度低于土表温度6.7℃.试验结果有助于进一步认识此类桩基回填土实际回冻过程,为确定模型试验控温条件及数值模拟边界条件提供参考.     

Nanoengineering of amino - functionalized mesoporous silica nanospheres as nanoreactors

Selective functionalization of mesoporous silica nanospheres (MSNs) is crucial for nanoengineering of MSNs. Herein, we have combined “surface-protected etching strategy” and “cationic surfactant assisted etching strategy” to prepare functionalized MSNs with externally attached amino groups. The externally attached NH2 groups endow the catalysts with excellent catalytic performance for nitroaldol reaction between nitromethane and benzaldehyde. In addition, those NH2-MSNs can also be used to support gold nanoparticles, which display very good catalytic performance for reduction of 4-nitrophenol. It can be envisioned that the synthesis protocol developed in this work could also be extended to nanoengineered MSNs, which provides opportunities for nanoreactors design.     

BEM Analysis of Wave Propagation in a Water-Filled Borehole in an Anisotropic Solid

This paper describes a time-domain boundary element method developed to analyze the interactions of acoustic and elastic waves near the interfaces between water and an anisotropic elastic solid. Two models are analyzed with one being the interface between two half spaces of fluid and solid and the other being a fluid region sandwiched by half space domains of anisotropic elastic solids. Both monopole and dipole point sources are used to generate an initial pressure wave in the fluid. Some snapshots of the transient wave behavior near the fluid-solid interfaces are given. The effect of the anisotropy in the solid on the pressure waveforms in the fluid is discussed. The numerical results allow detailed arrival identification and interpretation of acoustic and elastic waves propagating along the fluid-solid interfaces.     

Mechanical response to axial strain in WS2 nanotubes

In order to take advantage of inorganic nanotubes for their use with pragmatic purposes, characterization of their mechanical properties becomes a relevant issue. In the present study, a series of results on the mechanical properties of WS₂ nanotubes of several diameters and two main lattice orientations was obtained by the implementation of molecular dynamics simulations using an interatomic potential of the Stillinger-Weber kind. A Young’s modulus for nanotubes of H polytype close t...     

Growth mechanisms of Ag and Cu nanodendrites via Galvanic replacement reactions

Dendritic silver and copper crystals were produced via Galvanic replacement reactions on zinc and aluminum plates, respectively. The growth orientations of these metals were determined using electron microscopy. The results showed that a fast crystal growth associated with a high concentration of metal cations led to kinetically controlled growth along the <112> axes of the cubic close-packed structures. However, a slow growth rate resulted in thermodynamically controlled growth along the ...     

鸡蛋中全氟辛烷磺酸以及相关全氟化合物的污染现状

目前环境中全氟有机化合物(PFCs)的污染引起了人们的广泛关注. 近期的研究发现, 中国人血中全氟辛烷磺酸(PFOS)的浓度明显高于其他国家. 本研究的目的是: (1) 检测中国市场鸡蛋中PFCs的浓度和组成; (2) 对人类健康进行初步的风险评价. 采集于中国8个地区的鸡蛋样品用来检测11个全氟有机化合物. 结果显示蛋黄几乎100%含有PFOS, 而蛋白里未检测到(<0.08 ng/g(湿重)). 在全氟烷基磺酸盐(perfluoroalkylsulfonates)中, 只有PFOS在所有鸡蛋中被检测出. 而在全氟烷基羧酸(perfluoroalkycarboxylates)中, 全氟十一酸(perfluoroundecanoic acid, PFUnDA)在所有鸡蛋中被检测出, 全氟辛酸(perfluorooctanoic acid, PFOA)和全氟癸酸(perfluorodecanoic acid, PFDA)分别在75%和50%的鸡蛋样品中被检测出. 鸡蛋中PFOS的浓度范围是45.0～86.9 ng/g(湿重). 风险评价结果显示, 目前中国鸡蛋中PFOS的浓度不会对人类产生即时危害.     

实验测得的C2-C6二元羧酸溶液的冻结温度:冰核核化过程中的重要指标

由于大气气溶胶影响着地球辐射总量的平衡与能量的估算, 有机化合物作为气溶胶和云凝结核(cloud condensation nuclei, CCN)的重要组成成分, 其重要性已经越来越引起科学家们的重视. 而低分子量二元羧酸(low molecular weight dicarboxylic acids, LMWDCA)作为大气(包括云和雾)中气溶胶的重要成分,其在大气中的传输与转化过程中的作用尤其是对冰核(ice nuclei, IN)核化过程的影响已经成为当前的一个重要的前沿科学研究领域. 本研究利用麦吉尔大学的冻结核记数仪分别测量了不同pH的水溶液(超纯净水与自来水)中单纯态的与混合态的低分子量二元羧酸(C2-C6)液滴的冻结温度. 结果显示, 低分子量二元羧酸(C2-C6)自来水溶液的冻结温度明显的高于其相应的超纯净水溶液. 不同混合态的二元羧酸(C2-C6)的纯净水和自来水溶液液滴的平均冻结温度范围分别是: (-24.1±2.8)~(-21.3±3.9)℃和(-10.2±2.2)~(-9.5±2.2)℃, 而所测对照水(超纯净水与自来水)溶液液滴的平均冻结温度则分别是(-22.6±3.5)和(-11.2±2.4)℃. C2-C6二元羧酸的加入对于水溶液液滴的冻结温度增高的促进作用并不显著.     

功能绝缘材料加工工艺对电润湿显示器性能的影响

电润湿显示器是基于氟树脂层（如AF1600）作为疏水绝缘层,通过外加电压来改变液体在其表面润湿性来达到显示效果的装置,为了使光刻胶层和氟树脂层有很好的粘结性能,对氟树脂表面进行离子刻蚀来增大其润湿性. 光刻后需恢复氟树脂疏水性以恢复其电润湿特性. 常用方法是通过高温回流(High Temperature Reflow Method)的方法使刻蚀后的氟树脂表面熔融流平,但高温会造成光刻胶材料黄变,像素格变形等缺陷. 本文通过蒸汽溶解法(Vapor Redissolve Method)代替高温回流法来恢复氟树脂层的疏水性能,使用氟碳溶剂（HFE7100）蒸汽溶解氟树脂层粗糙表面形成溶胶状态,加热蒸发溶剂后使表面恢复疏水性质. 本文针对蒸汽溶解法溶解时间、干燥温度和干燥时间等条件进行探究,并对高温回流法和蒸汽溶解法对电润湿显示器产生的物理和光电影响进行了对比研究.     

基于相变操控的电润湿显示油墨填充与封装工艺研究

彩色油墨的填充与封装工艺是电润湿显示制造技术的核心,如何提高填充均匀性和制程效率仍然是电润湿显示技术量产的关键挑战之一。本文提出一种基于相变操控的电润湿显示油墨创新填充和封装方法,即在空气环境中完成油墨液相填充,经低温凝固后投入液体环境完成封装。该方法有效规避了在传统液下环境中填充涉及的油/水/固三相界面操控的复杂性,提高了填充工艺的兼容性和稳定性。对油墨厚度的分析结果表明,基于相变操控填充油墨厚度与像素墙高度的相关性更好,较传统自组装填充具有更好的膜厚控制性。相变操控填充电润湿显示器件的光电响应处于合理水平。本研究有效解决了电润湿显示油墨填充的技术瓶颈,对推进电润湿显示技术的应用具有重要意义。