CDI二维浓度传质模型的建立以及实验验证

电容去离子技术(CDI)作为一种新兴的水处理脱盐技术,因其具有诸多优异性能而受到广泛关注。厘清CDI的传质机制是理论研究的焦点。通过对已有经验模型的分析,从沿流向方向和垂直流向方向两个方面,考虑了电场迁移以及传质扩散等因素,提出了一种新的CDI二维浓度传质模型,对CDI在除盐过程中的离子扩散及浓度分布规律进行模拟探究,根据实际实验结果对该模型进行实验验证及参数修正。结果表明,该二维模型可以较好地模拟CDI除盐过程。将该二维模型利用COMSOL软件进行模拟,观测CDI在除盐过程中的内部浓度变化。并针对存在问题提出合理化建议,为CDI技术的未来发展提供理论支撑。     

高回弹氨纶的制备方法和研究

通过在预聚物溶液中再次添加定量的4,4-二苯基甲烷二异氰酸酯,制备出一种高回弹氨纶,研究证明,这种高回弹氨纶具有更加优良的回弹性能,解决了一些特殊领域对高回弹氨纶的要求。     

迭代全息搜索策略及其在动力学参数估计中的应用

针对反应动力学参数估计的复杂性,设计了一种新颖的优化方法-迭代全息搜索策略(IHRS).全息搜索策略(HRS)将多维空间中的寻优问题直观地通过二维全息图上的近邻搜索来实现,是一种全局搜优效率较高的确定性优化方法,但它只能用于离散系统的优化.IHRS通过对连续变量进行离散化处理,并运用迭代计算逐步缩小离散系统与原连续系统的偏差,将复杂的多维连续变量优化问题转化为多个串联的较为简单的离散变量组合优化问题,再运用HRS寻优.并讨论了等分区间数、搜索域收缩率、群规模等参数对IHRS搜优效率的影响.六维Alpine函数测试表明,IHRS的全局优化性能优于单纯形法和遗传算法(GA).将IHRS应用于SO2催化氧化反应动力学模型参数的估计,取得了满意的结果.     

Elongation and Contraction of Scallop Sarcoplasmic Reticulum (SR): ATP Stabilizes Ca2+-ATPase Crystalline Array Elongation of SR Vesicles

The Ca²⁺-ATPase is an integral transmembrane Ca²⁺ pump of the sarcoplasmic reticulum (SR). Crystallization of the cytoplasmic surface ATPase molecules of isolated scallop SR vesicles was studied at various calcium concentrations by negative stain electron microscopy. In the absence of ATP, round SR vesicles displaying an assembly of small crystalline patches of ATPase molecules were observed at 18 µM [Ca²⁺]. These partly transformed into tightly elongated vesicles containing ATPase crystalline arrays at low [Ca²⁺] (≤1.3 µM). The arrays were classified as ‘’tetramer’’, “two-rail” (like a railroad) and ‘’monomer’’. Their crystallinity was low, and they were unstable. In the presence of ATP (5 mM) at a low [Ca²⁺] of ~0.002 µM, “two-rail” arrays of high crystallinity appeared more frequently in the tightly elongated vesicles and the distinct tetramer arrays disappeared. During prolonged (~2.5 h) incubation, ATP was consumed and tetramer arrays reappeared. A specific ATPase inhibitor, thapsigargin, prevented both crystal formation and vesicle elongation in the presence of ATP. Together with the second part of this study, these data suggest that the ATPase forms tetramer units and longer tetramer crystalline arrays to elongate SR vesicles, and that the arrays transform into more stable “two-rail” forms in the presence of ATP at low [Ca²⁺].     

基于EGSnrc仿真的二维电离室剂量探测器的室壁厚度确定方法

室壁厚度是二维电离室剂量探测器的重要设计参数。在二维电离室剂量探测器的单元空腔几何参数确定的情况下,利用蒙特卡罗仿真方法建立了探测器室壁仿真计算的简化模型,并利用EGSnrc程序对模型进行了仿真计算,给出了室壁厚度的参考数值。结果表明,当空腔为直径4.5 mm、高5 mm的圆柱形时,在能量为1.25 MeV射线下,为达到1%的测量精度,电离室前壁厚度需达到4.4 mm,侧壁厚度需达到1.5 mm;在1.25~4 MeV射线能量范围内使用时,为达到1%的测量精度,侧壁厚度需达到5 mm。本文研究结果可作为该种探测器的设计依据。     

二维光催化材料研究进展

以石墨烯为代表的二维材料因其厚度尺寸和层状结构特点,表现出许多独特的物理化学性质,比如导电率高、化学性质稳定以及比表面积大等特点,在环境、材料、能源和催化领域具有广泛的应用前景.而二维材料与半导体复合,不仅可以拥有单个组分的优势,而且每种组分之间的相互作用还可能会引起本征性能的协同增强,因此二维材料-半导体复合光催化剂...     

Hippocampal Over-Expression of Cyclooxygenase-2 (COX-2) Is Associated with Susceptibility to Stress-Induced Anhedonia in Mice

The phenomenon of individual variability in susceptibility/resilience to stress and depression, in which the hippocampus plays a pivotal role, is attracting increasing attention. We investigated the potential role of hippocampal cyclooxygenase-2 (COX-2), which regulates plasticity, neuroimmune function, and stress responses that are all linked to this risk dichotomy. We used a four-week-long chronic mild stress (CMS) paradigm, in which mice could be stratified according to their susceptibility/resilience to anhedonia, a key feature of depression, to investigate hippocampal expression of COX-2, a marker of microglial activation Iba-1, and the proliferation marker Ki67. Rat exposure, social defeat, restraints, and tail suspension were used as stressors. We compared the effects of treatment with either the selective COX-2 inhibitor celecoxib (30 mg/kg/day) or citalopram (15 mg/kg/day). For the celecoxib and vehicle-treated mice, the Porsolt test was used. Anhedonic (susceptible) but not non-anhedonic (resilient) animals exhibited elevated COX-2 mRNA levels, increased numbers of COX-2 and Iba-1-positive cells in the dentate gyrus and the CA1 area, and decreased numbers of Ki67-positive cells in the subgranular zone of the hippocampus. Drug treatment decreased the percentage of anhedonic mice, normalized swimming activity, reduced behavioral despair, and improved conditioned fear memory. Hippocampal over-expression of COX-2 is associated with susceptibility to stress-induced anhedonia, and its pharmacological inhibition with celecoxib has antidepressant effects that are similar in size to those of citalopram.     

全二维气相色谱-质谱对喷气燃料的特征筛选分析

以各地炼油厂收集的21个喷气燃料样品为研究对象,采用全二维气相色谱质谱法进行定性和半定量分析.配置了极性-非极性柱系统的全二维气相色谱-串联单四极杆质谱仪(GC×GC-qMS)可以显著提高峰容量,在分析组分复杂的喷气燃料时具有明显优势.讨论了基于百分比响应值的方差分析中F比值法,筛选喷气燃料的特征组分,比较了几种确定F...     

基于任意形状平面阵列的二维测向技术研究

实际测向环境对天线阵的布阵形状要求较严,形状选择的合理与否将直接影响测向精度、测向带宽及测向频谱的范围.针对阵列形状和二维测向的实际问题,建立了利用任意形状平面阵列对空间多目标源进行二维测向的数学模型,并利用该模型和MUSIC算法对空间多目标实现了超分辨二维测向,简要地概括了算法实现的具体步骤,从而对以往的测向技术有了一定程度上的改进.计算机仿真结果表明了理论分析的正确性及数学模型的有效性.     

基于ACGAN和模型融合的电机轴承故障诊断方法

电机轴承疲劳试验成本较高和故障数据不足导致利用机器学习等人工智能算法进行故障诊断时效果不佳。另外,单一模型对电机轴承故障诊断的准确率也较低。为解决这两个问题,提出了一种结合辅助分类器生成对抗网络(ACGAN)和模型融合的电机轴承故障诊断方法。首先将采集到的振动数据转换为二维灰度图,对每个灰度图添加标签后输入ACGAN模型,生成大量与原始数据高度拟合的新样本。然后将新样本与原始样本混合,经数据降维后输入由6个基学习器和1个元学习器融合而成的模型中。最后由融合模型输出诊断结果。试验证明,ACGAN和模型融合能有效提高电机轴承故障诊断的准确率。