从电解槽的密封形式谈离子膜的安装

从电解槽单元槽的连接形式就生产中遇到的问题探讨了膜的安装及选用。     

Android安全加固技术

为了保护Android智能手机安全,在深入分析Android系统安全机制的基础上,提出了一个基于强制访问控制的安全加固技术.该技术首先通过修改Android内核,添加一个平台无关的强制访问框架,其次为进程、文件等系统对象添加安全属性,最后通过制定一套细粒度的强制访问规则,对应用程序实施强制访问控制.通过在模拟环境中的测...     

聚乙烯-碳纳米管串晶的高效制备(英文)

We report a novel method to prepare nanohybrid shish-kebab (NHSK) structure of polyethylene (PE) and carbon nanotube (CNT). Pristine CNTs without surface modification with high concentration was effectively dispersed in xylene solution by a simple shearing method, which induces the quick crystallization of PE in xylene to form a novel NHSK structure with more dense and smaller PE kebab on CNT axis. The flocculated NHSK product was transferred quickly from the xylene solution to the ethanol solution, in order to shorten the preparation time. The freeze-drying method was used in vacuum instead of high-temperature drying to avoid the aggregation of NHSK product. These improvements allow the formation of NHSK with an absolute yield of 200 mg·h-1 , which is 2000 folds of that reported previously. It is favorable to apply this structured material in high performance nanocomposite, by improving the compatibility of CNTs in polymer and the interfacial force between CNTs and polymer.     

焦化产品全水分测定改进方法

主要论述了焦化产品全水分测定的改进方法,即恒重法,通过和蒸馏法实验结果的对比,综合实验室条件及恒重法的优点,建议选择恒重法作为企业的分析方法.     

飞行器热解炭化材料烧蚀产物对等离子体流场的影响规律

高速飞行器表面防热材料在气动加热产生的高温下会热解烧蚀,烧蚀产物进入空气边界层流场后,与流场中的高温空气发生复杂化学反应,对飞行器周围空气流场中组分浓度和等离子体分布产生影响.基于求解热化学非平衡Navier-Stokes方程,建立耦合烧蚀壁面的三维等离子体流场计算方法.理论预测电磁衰减测量项目第2次飞行试验(RAMC...     

基于Fourier-Mellin变换和相位相关的MEMS旋转角度的测量

MEMS器件微结构的运动特性影响器件的性能和可靠性。为实现微结构周期运动过程中各个时刻的旋转角度的测量,提出一种基于傅里叶梅林(Fourier-Mellin)变换和相位相关算法的旋转角度测量方法。利用傅里叶梅林变换算法的旋转不变性,将图像空间坐标转换为对数极坐标的参数空间,旋转角度变化转化为平移的运动,然后利用相位相关的亚像素平移测量算法,得到微结构旋转角度。实验结果表明,该算法旋转角度测量分辨率达到0.01°,计算量较小且具有抗干扰能力。     

聚ε-己内酯的合成及其复合材料研究

聚（ε-己内酯）作为一种合成的脂肪族聚酯,由于其良好的生物可降解性、生物相容性以及药物透过性,在生物医学领域得到了广泛研究。介绍了聚己内酯合成的各种催化引发体系及辅助合成手段,综述了其复合材料包括无机纳米粒子杂化和线性非线性共聚物等的研究现况,介绍了聚己内酯的生物应用情况,探讨了这种可降解材料今后的发展方向。     

基于脊路跟踪的变分非线性调频模态分解方法

针对多个辐射源信号混合构成的多分量信号分离问题,提出基于脊路跟踪的变分非线性调频模态分解算法. 该方法使用改进的脊路重组算法对时频分布图中各分量瞬时频率进行提取,将提取出的各分量瞬时频率作为变分非线性调频模态分解的预设频率;利用重构后的多分量信号进行瞬时频率提取,更新预设频率后继续模态分解;重复上述过程,直到迭代前、后频率差值小于预设阈值,输出对应的模态分解结果. 实验结果表明,基于脊路跟踪的变分非线性调频模态分解算法比经典变分非线性调频模态分解算法具有更好的多分量信号分离效果.     

Characterization of fused Fe-Cu based catalyst for higher alcohols synthesis and DRIFTS investigation of TPSR

Fused Fe-Cu based catalyst for higher alcohols synthesis (HAS) is characterized by XRD, TG-DTA, H₂-TPD and DRIFTS of CO adsorption. The results of XRD reveal that the fused Fe-Cu based catalyst consists of Cu₂O, CuFeO₂ and CuFe₂O₄ species. After reduction, the metallic Fe and Cu are the main species, but minor CuFeO₂ and CuFe₂O₄ species are also present. H₂-TPD shows that in comparison with the pure Fe- or Cu-based sample, the ability of Fe-Cu based catalyst for activation of H₂ is higher and the stronger metal-hydrogen bonds are formed. DRIFTS of CO adsorption indicates that CO is adsorbed on both metal and metal ion sites, where the dissociation of CO to C* and O* species and the formation of CO₂ are observed. In situ DRIFTS investigation of CO + H₂-TPSR over the Fe-Cu based catalyst shows that the dissociative activation of H₂ is more difficult than the activation of CO, and carbonaceous and hydrocarbon fragment species only appears after the dissociative activation of H₂. In addition, HAS over the Fe-Cu based catalyst is very complicated, where various intermediates including = CH₂, − CHO, − OOCH, − OH and − C(= O)-R exist.     

列车运行网络抗毁性能的量化研究*

为尽可能减少由于自然灾害导致铁路运输受阻甚至中断情况下受影响的列车数,提出了对现有列车运行方案以抗毁性优化为目标的量化分析方法.首先基于当前列车运行方案建立列车运行网络模型,该模型以实际铁路站点为节点,以实际铁路线为边,以每条边开行的列车数量为边权重;随后提出了一个称之为度权效应的抗毁性评价指标,并以该评价指标为目标函数,使用改进粒子群算法对网络权重进行优化.仿真结果得出了优化前后列车运行网络的抗毁性评价值分别为0.8881和0.9063,表明可通过量化分析方法来刻画列车运行网络的抗毁性能.