(7-甲氧基-4-亚甲基)香豆素基-单氮杂18-冠-6的合成及其离子识别功能(Ⅰ)——合成及光谱性质

合成、鉴定了题示光敏离子载体（ＭＭＣ－ＭＡＣ（Ｏ５ ））。基于不同ｐＨ值水溶液中吸收和荧光光谱的变化, 计算得该试剂基态和激发态分子的酸性常数（ｐＫａ ＝ ８．８４, ｐＫａ ＝ ５．１１）。基于在不同溶剂中荧光光谱的变化, 由Ｓｏｌｖａｃｈｒｏｍ ｉｃ法, 借助Ａｌｃｈｅｍ ｙ ２０００ 量化计算软件, 估算得该分子的基态和激发态偶极矩, 分别为３．１１Ｄ和８．１３Ｄ。同时发现, ＭＭＣ－ＭＡＣ（Ｏ５ ）水溶液除氧后其荧光强度奇迹般地提高近２０ 倍, 并伴随一定强度的延迟荧光发射。其荧光或延迟荧光强度与浓度在一定范围内呈良好线性关系。检测限分别为２×１０－ ９和１．３×１０－ ８ ｍ ｏｌ·Ｌ－ １ 。     

嵌入式Linux中MMC设备功能的实现

主要介绍了在嵌人式Linux环境中,基于Intel XScale架构的处理器PXA250下MMC设备功能的实现方法。首先介绍了MMC存储卡的基本原理,以及PXA250中的MMC控制器模块的情况,然后讲述了在嵌人式Linux中如何实现MMC设备的功能。     

基于模块化多电平光伏并网动态建模与仿真研究

鉴于传统三电平逆变电路存在谐波含量高的缺点,在分析模块化多电平换流器(MMC)工作原理的基础上,提出使用模块化多电平电路实现光伏并网逆变功能,采用微分-跟踪器法实现光伏阵列最大功率点跟踪(MPPT)及逆变器PQ解耦控制,实现了光伏系统以单位功率因数并网.在PSCAD中建立光伏并网系统动态仿真模型,仿真结果表明,所建模型具有开关损耗低、谐波量小的优点,验证了所提方法的正确性和可行性.     

TOF-SIMS investigations on thermally treated copper–molybdenum films on a carbon substrate

Metal-matrix composites are made of materials with different physical and chemical properties. It is possible to change the mechanical, thermal and electrical properties by variation of the mass ratio of the components; therefore, metal-matrix composites have great value for industrial and technological applications. Copper–carbon composites have a good chance to be used as heat sinks for electronic components, which can be explained by their high thermal conductivity, low density and an adjustable coefficient of thermal expansion. On the other hand, the mechanical adhesion of copper and carbon is extremely weak because of their immiscibility and weak chemical interactions. In order to compensate for the low wettability of carbon by copper, a thin molybdenum intermediate layer is used as an adhesion promoter. In this work a time of flight secondary ion mass spectrometry technique was primarily used to detect the carbide formation in the molybdenum and copper layers, depending on different temperature conditions during sputter deposition and annealing afterwards. The CuMo layers were deposited by magnetron sputtering. The adhesion of the samples was determined by a destructive pull-off test. We found that heat treatment mainly modifies the carbide formation in the molybdenum and copper layers.     

The wetting behaviour of silver on carbon, pure and carburized nickel, cobalt and molybdenum substrates

Properties such as thermal and electrical conductivity or the expansion behaviour of silver matrix composites with carbon based inclusions are strongly affected by the contact angle between carbon and silver. In order to promote wetting of carbon, insertion of metallic interlayers such as nickel, cobalt or molybdenum is a feasible approach. This paper presents contact angle measurements done with the sessile drop method on carbon substrates (glassy carbon, polycrystalline graphite) and on pure nickel, cobalt and molybdenum foils. The ability of these interlayer elements to lower the high contact angles of silver on glassy carbon (117°) and polycrystalline graphite (124°) under vacuum conditions was verified. Unlike nickel (30°) and cobalt (26°), molybdenum (107°) nevertheless was not wettable by liquid silver (at 1273 K) under vacuum conditions. ToF-SIMS was used to identify oxygen on the surface, causing higher contact angles than expected. After oxide reduction a contact angle of 18° on molybdenum was detected. Furthermore, the influence of carbon diffusion on the contact angle was investigated by gas phase carburization of the metal foils. ToF-SIMS and XRD identified dissolved carbon (Ni, Co) and carbide formation (Mo). However, only nickel and cobalt showed a slight decrease of the contact angle due to carbon uptake.     

Reinforcement characterization of metal matrix composites by DSC technique

The metal matrix composites (MMC) being of very high interest for the aerospace industry, particularly to build up thermal-structural components, it is important to have available methods which are easy and simple to conduct for characterization of the mechanical strength of the material.This study shows that the differential scanning calorimetry (DSC) may enable us to quantify the energy of cohesion in the fiber/matrix interface area of an aluminium composite reinforced by SiC whiskers.The energy of cohesion is dependent on the state of reinforcement compared to the matrix strength and take into account both chemical and mechanical characteristics of the cohesion in the fiber/matrix interface area. However, this method would require a systematic calibration based on tests of mechanical characteristics.

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Zusammenfassung Metallmatrixverbundwerkstoffe (MMC) sind für die Raumfahrtindustrie von großem Interesse, insbesondere zum Bau thermisch-struktureller Komponenten ist es wichtig, Methoden zur Verfügung zu haben, die leicht und einfach zur Charakterisierung der mechanischen Festigkeit der Materialien benutzt werden können.Es wurde gezeigt, daß DSC es ermöglicht, die Kohäsionsenergie im Fiber/Matrix-Grenzflächengebiet eines mit SiC-Whiskern verstärkten Aluminiumverbundstoffes quantitativ zu bestimmen.Diese Kohäsionsenergie ist abgängig vom Verstärkungsgrad bezogen auf die Matrixfestigkeit und berücksichtigt sowohl die chemischen als auch mechanischen Eigenschaften der Kohäsion im Fiber/Matrix-Grenzflächengebiet.In jedem Falle bedarf diese Methode einer systematischen Kalibrierung anhand von Test der mechanischen Eigenschaften.

     

SiCp/6061Al复合材料激光表面熔化及合金化显微组织与耐蚀性

为提高颗粒增强铝基复合材料耐蚀性，对ＳｉＣｐ／６０６１Ａｌ复合材料进行激光表面熔化和激光表面合金化。结果表明：激光表面熔化后，因熔化层中形成大量耐蚀性低的针状Ａｌ_４Ｃ_３相及Ａｌ_４ＳｉＣ相而使激光表面熔化层耐蚀性降低，以Ｎｉ－Ｃｒ－Ｂ粉末为原料对ＳｉＣｐ／６０６１Ａｌ复合材料进行激光表面合金化后，合金层耐蚀性明显提高。     

氨基己酸为配基的新型弱阳离子交换/疏水双功能色谱固定相对蛋白质的分离纯化

以硅胶为基质、氨基己酸为配基制备了一种新型弱阳离子交换/疏水（WCX/HIC）双功能混合模式色谱固定相。该固定相配基具有一定的疏水性且含有羧基,在高盐浓度下表现为HIC的性质,可作为HIC固定相使用;在低盐浓度条件下表现为离子交换的性质,可作为WCX固定相使用。分别考察了该介质在WCX和HIC两种模式下对标准蛋白质的分离性能,并与商品柱进行比较。结果表明,所合成的WCX/HIC双功能固定相在WCX和HIC两种模式下对蛋白质均有较高的分离度和选择性,且分离能力与商品柱相当,两种模式下标准蛋白质的质量和活性回收率均大于93%,表明该柱具有“一柱二用”的功能,适于生物大分子的分离纯化。基于此双功能色谱柱构建的在线单柱二维液相色谱（2DLC-1C）可在60 min内实现8种蛋白质的快速分离。在70 min内完成了对蛋清中溶菌酶的二维纯化,纯度可达到98.3%。该技术中一根色谱柱可当作两根色谱柱使用,对蛋白质组学研究和重组蛋白药物的生产具有重要的应用价值。     

电网不平衡条件下模块化多电平变换器控制策略

当电网处于电压不平衡状态时,MMC的内部会产生环流.环流中存在二倍频的正序、负序和零序分量,增加了系统的不稳定性.针对电网不平衡情况下MMC二倍频环流抑制的问题,文中提出一种基于线性自抗扰控制器的环流抑制策略.根据瞬时功率理论推导出环流参数的数量关系,在此基础上设计了基于线性自抗扰控制策略的环流控制器来抑制环流.最后利...     

一种混合模式反相弱阳离子交换色谱填料的制备及其保留机理

采用“点击化学”的合成方法制备了一种混合配体的辛基-羧基共同键合硅胶（OCS）材料,经元素分析和红外光谱表征,证明了辛基和羧基官能团均已成功键合到硅胶表面。将其作为混合模式反相弱阳离子交换（RP/WCX）的固定相填料,以3种同系物阳离子表面活性剂作为探针分子,定量研究了该固定相的混合模式保留机理,考察了溶质保留因子与盐浓度和溶质亚甲基数目的关系,验证了混合模式固定相的单点和两点保留机理的数学模型,并进一步将其应用于一系列标准碱性混合物的分离。结果表明：两点保留机理更加符合实验的结果;根据混合模式两点保留机理的数学方程,可以得到单一的疏水或离子交换作用力对总保留的影响,对混合模式色谱的实际分离应用提供了有价值的参考。本文建立了反相弱阳离子交换混合模式OCS固定相的保留机理的定量模型,并证明了该固定相在碱性化合物的分离中具有很大的应用前景。