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排序方式: 共有7114条查询结果,搜索用时 15 毫秒
1.
介绍了某病房楼给排水设计的特点,阐述了消防贮水池(水箱)兼作循环冷却水补水系统,自动喷水系统干管成环及湿式报警阀分散设置,热水系统采用即热式换热器等方面的设计方法。  相似文献   
2.
The characterization of the structure and internal dynamics of biomolecules is essential to understanding their biological function. Neutron scattering probes similar time- and length-scales to molecular dynamics simulation. Hence, simulation models of biomolecules have become invaluable in the interpretation of experimental neutron data. Here, we report on advances in the application of simulation in developing neutron scattering to investigate internal protein motions and, as an example of industrial relevance, in the derivation of physical models of use in biofuel renewable energy research.  相似文献   
3.
Micro-Raman spectroscopy is a convenient tool to probe individual objects with a feature size on the submicron scale. The phase, composition, and orientation of Pb(Zr,Ti)O3 fibers fabricated via hydrothermal processing have been characterized by this technique, with the working principles given in the paper. It is shown that the prepared PZT submicron fibers are of a tetragonal pervoskite phase, with Zr/(Zr + Ti) varying from 0.05 to 0.25. The spontaneous polarization has been confirmed to be along the length direction and one of its {1 0 0} planes parallel to the substrate plane.  相似文献   
4.
Yttrium-stabilized zirconia nanotubes (YSZNTs) were prepared using a conventional hydrothermal method, and their characteristics were compared with those of yttrium-stabilized zirconia nanoparticles (YSZNPs) synthesized in this study and with those of commercial YSZNPs (CYSZNPs). YSZNTs had widths and lengths of 20–30 nm and 100–700 nm respectively. The electrical conductivity of NiO (60.0 wt%)-loaded YSZNTs (40.0 wt%) was higher than those of NiO/YSZNPs and NiO/CYSZNPs at the same NiO loading. The zeta-potentials of YSZNTs in aqueous solution, determined by electrophoretic light scattering (ELS), indicated high positive surface charges at lower pH values, which is known to be related to surface stability, but negative values at high pH. The results of cyclic voltammetry (CV) and H2-temperature-programmed reduction (H2-TPR) confirmed that NiO(60.0 wt%)/YSZNTs (Ered = −0.445 mV) were more reduced than NiO/YSZNPs (Ered = −0.517 mV) and NiO/CYSZNPs (Ered = −0.516 mV).  相似文献   
5.
Human cystatin C (HCC), an amyloidogenic protein, forms dimers and higher oligomers (trimers, tetramers and donut like large oligomers) via a domain-swapping mechanism. The aim of this study was the characterization of the HCC oligomeric states observed within the pH range from 2.2 to 10.0 and also in conditions promoting oligomerization. The HCC oligomeric forms obtained in different conditions were characterized using size exclusion chromatography, dynamic light scattering and small-angle X-ray scattering. The marked ability of HCC to form tetramers at low pH (2.3 or 3.0) and dimers at pH 4.0–5.0 was observed. HCC remains monomeric at pH levels above 6.0. Based on the SAXS data, the structure of the HCC tetramer was proposed. Changes in the environment (from acid to neutral) induced a breakdown of the HCC tetramers to dimers. The tetrameric forms of human cystatin C are formed by the association of the dimers without a domain-swapping mechanism. These observations were confirmed by their dissociation to dimers at pH 7.4.  相似文献   
6.
为了探索环境湿度对煤尘浓度测量精度的影响,在分析激光散射法、β射线法和电荷感应法这3种主要测尘方法原理的基础上,在不同湿度条件下开展了煤尘浓度测量及其误差的实验分析,并指出了各自的补偿方法。煤尘浓度测量实验结果表明:当相对湿度为50%时,3种测尘方法的误差均小于7%;当相对湿度为60%~70%时,激光散射法的误差大于20%,β射线法和电荷感应法的最大误差都约为15%;当相对湿度大于70%时,3种测尘方法的误差都较大。通过对激光散射法和电荷感应法增加湿度检测系统,激光散射法根据湿度调整质量浓度转换系数,电荷感应法根据湿度调整算法的系数,β射线法则采用动态加热的补偿方法,以消除湿度的影响。  相似文献   
7.
Zhou Xiaojuan  Ban Shiliang 《半导体学报》2009,30(8):082001-082001-6
also indicate that scattering from half space phonon modes in the channel side plays a dominant role in mobility.  相似文献   
8.
Size and zeta potential are critical physicochemical properties of nanoparticles (NPs), influencing their biological activity and safety profile. These are essential for further industrial upscale and clinical success. However, the characterization of polydisperse, non-spherical NPs is a challenge for traditional characterization techniques (ex., dynamic light scattering (DLS)). In this paper, superparamagnetic iron oxide nanoparticles (SPIONs) were coated with polyvinyl alcohol (PVAL) exhibiting different terminal groups at their surface, either hydroxyl (OH), carboxyl (COOH) or amino (NH2) end groups. Size, zeta potential and concentration were characterized by orthogonal methods, namely, batch DLS, nanoparticle tracking analysis (NTA), tunable resistive pulse sensing (TRPS), transmission electron microscopy (TEM), asymmetric flow field flow fractionation (AF4) coupled to multi-angle light scattering (MALS), UV–Visible and online DLS. Finally, coated SPIONs were incubated with albumin, and size changes were monitored by AF4-MALS-UV-DLS. NTA showed the biggest mean sizes, even though DLS PVAL-COOH SPION graphs presented aggregates in the micrometer range. TRPS detected more NPs in suspension than NTA. Finally, AF4-MALS-UV-DLS could successfully resolve the different sizes of the coated SPION suspensions. The results highlight the importance of combining techniques with different principles for NPs characterization. The advantages and limitations of each method are discussed here.  相似文献   
9.
赵磊  胡超 《工程力学》2012,29(9):87-91
该文基于弹性动力学理论,采用复变函数与保角映射方法,研究了指数梯度材料中任意形孔洞对弹性波的散射与动应力集中,给出了问题的解析解.并以求解椭圆孔动应力集中系数为例,分析了入射波数和材料非均匀参数等对椭圆孔动应力分布的影响.  相似文献   
10.
The rapid identification of bacterial antibiotic susceptibility is pivotal to the rational administration of antibacterial drugs. In this study, cefotaxime (CTX)-derived resistance in Salmonella typhimurium (abbr. CTXr-S. typhimurium) during 3 months of exposure was rapidly recorded using a portable Raman spectrometer. The molecular changes that occurred in the drug-resistant strains were sensitively monitored in whole cells by label-free surface-enhanced Raman scattering (SERS). Various degrees of resistant strains could be accurately discriminated by applying multivariate statistical analyses to bacterial SERS profiles. Minimum inhibitory concentration (MIC) values showed a positive linear correlation with the relative Raman intensities of I990/I1348, and the R2 reached 0.9962. The SERS results were consistent with the data obtained by MIC assays, mutant prevention concentration (MPC) determinations, and Kirby-Bauer antibiotic susceptibility tests (K-B tests). This preliminary proof-of-concept study indicates the high potential of the SERS method to supplement the time-consuming conventional method and help alleviate the challenges of antibiotic resistance in clinical therapy.  相似文献   
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