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51.
Ellson R Stearns R Mutz M Brown C Browning B Harris D Qureshi S Shieh J Wold D 《Combinatorial chemistry & high throughput screening》2005,8(6):489-498
Compounds used in high throughput screening (HTS) are typically dissolved in DMSO. These solutions are stored automation-friendly racks of wells or tubes. DMSO is hygroscopic and quickly absorbs water from the atmosphere. When present in DMSO compound solutions, water can accelerate degradation and precipitation. Understanding DMSO hydration in an HTS compound library can improve storage and screening methods by managing the impact of water on compound stability. A non-destructive, acoustic method compatible with HTS has been developed to measure water content in DMSO solutions. Performance of this acoustic method was compared with an optical technique and found to be in good agreement. The accuracy and precision of acoustic measurements was shown to be under 3% over the tested range of DMSO solutions (0% to 35% water by volume) and insensitive to the presence of HTS compounds at typical storage concentrations. Time course studies of hydration for wells in 384-well and 1536-well microplates were performed. Well geometry, fluid volume, well position and atmospheric conditions were all factors in hydration rate. High rates of hydration were seen in lower-volume fills, higher-density multi-well plates and when there was a large differential between the humidity of the lab and the water content of the DMSO. For example, a 1536-well microplate filled with 2microL of 100% DMSO exposed for one hour to a laboratory environment with approximately 40% relative humidity will absorb over 6% water by volume. Understanding DMSO hydration rates as well as the ability to reverse library hydration are important steps towards managing stability and availability of compound libraries. 相似文献
52.
能带是决定固体特性的头等重要的因素。我们用光谱方法对单相YBa2Cu2Ox高T。超导体进行了研究,测量了样品的反射-吸收谱、Raman光谱和荧光光谱.其350和500nm吸收带以及390nm,560nm荧光峰来自晶格中Cu+发光中心,是跃迁过程1A1g(3d10)-1Eg和~3Eg(3d94s1)。其720nm和860nm荧光峰来自Cu2+发光中心,是由于自由离子光谱项2D在八面体晶场、正交晶系晶场中分裂为5个能级之间的跃迁。此外,还有一些光谱可能来自晶格中Cu3+发光中心,其481cm-1和551cm-1声子对说明了312cm-1处声子对与电子系统是强耦合。 相似文献
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Reproducibility of pyrolysis-gas chromatographic analyses of the mould Penicillium brevi-compactum 总被引:1,自引:0,他引:1
The reproducibility of multivariate measurements is discussed. Reproducibility of a second kind is defined, in which part of the variability between samples is described by a principal components model. The use of this generalized reproducibility is shown to give an improved precision in the pyrolysis-gas chromatography of a Penicillium species. 相似文献
58.
Ching-I Hsu John J. Steger Edgar A. DeMeo Aaron Wold Gerald S. Heller 《Journal of solid state chemistry》1975,13(4):304-306
Recent magnetic resonance results suggest that MnIn2S4 is antiferromagnetic with a Néel point near liquid helium temperature, in disagreement with previously reported dc (direct current) susceptibility measurements. The resonance data suggest that these susceptibility measurements were made at an applied dc field comparable to or greater than the critical field. This would tend to obscure observation of a magnetic transition, since some of the spins would be “flopped.” The susceptibility measurements have been repeated at a much lower applied field. From these new measurements, a Néel temperature of 4.9°K is obtained, in agreement with the resonance data, and an exchange parameter of 1430 is computed. 相似文献
59.
Compounds of the system FeAs2?xSex were ynthesized both as polycrystalline powders by direct combination of the elements and as single crystals by chemical vapor transport. Electrical and magnetic measurements were made on well-characterized samples. These measurements showed that the substitution of selenium for arsenic in the diamagnetic semiconductor FeAs2 results in metallic, paramagnetic behavior. These results are consistent with a band model proposed by Goodenough for compounds crystallizing in the marcasite structure. 相似文献
60.
Albert K.L. Fan Gerald H. Rosenthal Howard L. McKinzie Aaron Wold 《Journal of solid state chemistry》1972
Single crystals of FeAs2 and FeSb2 were prepared by chemical vapor transport using chlorine as the transporting agent. Electrical and magnetic measurements have been made on well-characterized samples. FeAs2 was found to be a diamagnetic semiconductor with a band gap of 0.22 eV. FeSb2 has an extremely narrow band gap and shows unusual electrical and magnetic properties. Aproposed band model is used to explain the experimental results. 相似文献