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排序方式: 共有123条查询结果,搜索用时 31 毫秒
1.
Th. Schalkhammer Ch. Lobmaier F. Pittner A. Leitner H. Brunner F. R. Aussenegg 《Mikrochimica acta》1995,121(1-4):259-268
A new optical sensor is presented, based on the analyte reaction resulting in swelling and shrinking of a thin polymer layer. Changing the concentration of ions in a new bisazide photo-cross-linked poly(vinylpyrrolidone) polymer results in a concentration-dependent volume change of the hydrated gel. The volume response of the sensor induced by different ions is fully reversible over more than 250 cycles. The response of the device depends on the type, the charge and the concentration of the ions. The sensor material is part of an optical thin film system which transforms the variations in volume of the polymer into spectral information. The steady state of the sensor response is obtained within 60 s. The response time is mainly limited by the pump rate, the back pressure and the total volume of the system but not by the swelling of the sensor polymer. A comparative study of ion effects has demonstrated a fundamental correlation of the polymer swelling properties with the Hofmeister series of chaotropic agents. Thus it is concluded that the photopolymer, which is solubilized in aqueous solutions by the interaction of its amide structure with the solvent, behaves like the backbone amide structure of proteins. 相似文献
2.
针对若干远海岛礁群系统封闭性的分布特点,将中心岛礁选址、各岛礁建设泊位数量和规模、仓库储存量、运输船型和数量以及航线设置、班期组织等作为规划内容,以整个运输网络系统总成本最低为原则,综合考虑了仓库存储理论,建立了兼顾“选址-库存-路径”的规划模型。结合所建模型特点,提出了双层并行搜索遗传算法,构建了以海上运输为基本交通方式的双向物流系统。最后,以我国南海为例进行建模并求解,采用不同算法并通过多组不同规模的算例进行演算比较,验证了所建模型和算法的有效性与合理性。 相似文献
3.
采用分子束外延法分别在650-920 ℃的Si(110)和920 ℃的Si(111)衬底表面生长出铁的硅化物纳米结构,并主要分析了920 ℃高温下纳米结构的形貌、组成相及其与Si 衬底的取向关系. 扫描隧道显微镜(STM)研究表明,920 ℃高温下,Si(110)衬底上生长的铁硅化合物完全以纳米线的形式存在,且其尺寸远大于650 ℃低温下外延生长的纳米线尺寸;Si(111)衬底上生长出三维岛和薄膜两种形貌的铁硅化合物,其中三维岛具有金属特性且直径约300 nm、高约155 nm,薄膜厚度约2 nm. 电子背散射衍射研究表明920 ℃高温下Si(110)衬底上生长的纳米线仅以β-FeSi2的形式存在,且β-FeSi2相与衬底之间存在唯一的取向关系:β-FeSi2(101)//Si(111);β-FeSi2 [010]//Si[110];Si(111)衬底上生长的三维岛由六方晶系的Fe2Si 相组成,Fe2Si 属于164 空间群,晶胞常数为a=0.405 nm,c=0.509 nm;与衬底之间的取向关系为Fe2Si(001)∥Si(111)和Fe2Si[120]//Si[112]. 相似文献
4.
The surface energy of MgO is determined using experimental data collected from equilibrated thermal grooves circumscribing island grains. Local equilibrium assumptions at each groove require that the Herring equations be satisfied at each data site, thereby yielding a large and overdetermined system of equations involving the surface energy . This inverse problem is then solved using a new technique that is statistical in nature and multiscale in implementation. The resulting discrete solution represents a statistically significant representation of the surface energy of MgO as a function of surface orientation. Comparisons to results derived from a more traditional approach, along with suggested further applications, are discussed. 相似文献
5.
We observed a strong, more than 16-fold, enhancement of Texas Red-labeled BSA fluorescence emission when deposited on silver colloid coated surfaces (SCCS). The same labeled protein deposited on silver island films (SIFs) showed an approximate 8-fold fluorescence enhancement. The lifetimes of Texas Red-BSA fluorescence are significantly shorter on silvered surfaces than on uncoated quartz substrate indicating a strong change in radiative decay rate of the dyes. We also observed a 36-fold increased brightness of overlabeled fluorescein-HSA deposited on silver colloid coated surface. Stronger enhancement observed for overlabeled Fl-HSA protein indicates that presence of silver particles partially decreased self-quenching. Our results indicate that surfaces coated with silver colloids are valuable substrates for metal-enhanced fluorescence. 相似文献
6.
7.
A. Saito K. Takahashi Y. Takagi K. Hanai Y. Tanaka M. Akai-kasaya S. Shin T. Ishikawa M. Aono 《Surface science》2007,601(22):5294-5299
To solve difficulties of instability and inaccuracy in synchrotron radiation based scanning tunneling microscopy, a method to reduce noise was investigated. New insulator-coat tips were developed to shut out electrons coming from a wide area that damage the spatial resolution. By changing the exposed conductive area at the end of the insulator-coat tips, the effect of noise reduction was estimated. The tip with an exposure area of 50 nm in diameter was found to reduce noise effectively. Also a key discriminating condition was found to obtain the local signal, which is based on the modulation of the X-ray-induced tip current caused by excitation of the specific element. 相似文献
8.
STUDIES ON THE MESOZOIC MARGINAL ARC SYSTEM OF THE SOUTHEAST COAST AND TAIWAN IN CHINA 总被引:1,自引:0,他引:1
The southeast coastal Zhejiang, Fujian, Guangdong provinces and Taiwan in China comprised an important area in ancient Asia where the Yenshanian continental margin magmatic arc well developed in the late Mesozoic time. It is believed that the oceanic trench and subduction zone are situated on the east side of the Central Range in Taiwan. It seems unlikely that the so-called Hercynian-Indosinian ancient island arc folded system would have occurred in this region. 相似文献
9.
Cunji Yan Yongchong ChenAizi Jin Ming WangXiangdong Kong Xifeng ZhangYu Ju Li Han 《Applied Surface Science》2011,258(1):377-381
Fabrication of the gold micro/nano-structure in a controlled manner has recently attracted considerable interest for its potential applications. With the help of the AFM and XRD measurements, our research on the annealing of the evaporated thin gold films under different thermal environments reveals that O2 molecule, of which the influence has been generally ignored in the prevenient literatures, can play a very important role in the formation of gold island film. It is experimentally found that the molecule oxygen-driven migration of gold atoms can only occur at a high enough temperature. The time-dependent morphological development of the thin gold film annealing in O2 is also observed, which is determined by the reduction of the whole interface energy. The morphological features of the Au islands, such as the flat top surfaces and the steep edges, point to the essential role of the interaction between oxygen and the specifically oriented gold surface during the structural evolution. 相似文献
10.
回顾国内外小腿前外侧岛状皮瓣的研究成果,总结了小腿前外侧岛状皮瓣的应用解剖学基础和临床应用,讨论了目前报道的小腿前外侧岛状皮瓣修复小腿下段皮肤缺损的优缺点,并对优化该皮瓣在临床上的应用提出了展望. 相似文献