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131.
Novel furo, thieno and pyrrolo[2,3‐b]pyrazole cyanine dyes were synthesized. The structure‐photosensitization properties correlation of the dyes were examined in 95% ethanol solution by absorption spectroscopy. The chemical structure of the starting biheterocyclic compounds and their derived cyanine dyes were confirmed by elemental analysis, IR and 1H NMR spectroscopy. 相似文献
132.
碘溴化银乳剂薄片颗粒的潜影分散与碘离子在颗粒中的分布有关。本文用交叉光楔曝光技术测定了由次潜影造成的潜影分散,并根据所测出的潜影分散度和乳剂的表面感光度,对内、表敏的分布作了分析。结果表明,碘离子分布在颗粒边缘的乳剂,其表面潜影分散度要比碘离子均匀分布的颗粒更甚,后者且表现出内、表敏度竞争的现象。 相似文献
133.
A delayed coincidence method, time-interval analysis (TIA), has been applied to successive – decay events on the millisecond time-scale. Such decay events are part of the 220Rn216Po (T1/2 145 ms) (Th-series) and 219Rn215Po (T1/2 1.78 ms) (Ac-series). By using TIA in addition to measurement of 226Ra (U-series) from -spectrometry by liquid scintillation counting (LSC), two natural decay series could be identified and separated. The TIA detection efficiency was improved by using the pulse-shape discrimination technique (PSD) to reject -pulses, by solvent extraction of Ra combined with simple chemical separation, and by purging the scintillation solution with dry N2 gas. The U- and Th-series together with the Ac-series were determined, respectively, from alpha spectra and TIA carried out immediately after Ra-extraction. Using the 221Fr217At (T1/2 32.3 ms) decay process as a tracer, overall yields were estimated from application of TIA to the 225Ra (Np-decay series) at the time of maximum growth. The present method has proven useful for simultaneous determination of three radioactive decay series in environmental samples. 相似文献
134.
135.
采用约束刻蚀剂层技术, 以亚硝酸钠为先驱物, 通过电化学氧化产生刻蚀剂(硝酸)刻蚀铝, 并以NaOH为捕捉剂, 在电极模板上形成约束刻蚀剂层. 在金属铝表面加工出梯型槽微结构, 加工分辨率约为500 nm. 通过测量表面氢离子浓度, 对捕捉剂的约束效果进行了分析. 相似文献
136.
M Trætteberg L.S KhaikinO.E Grikina S.I KozhushkovA de Meijere 《Journal of Molecular Structure》2002,641(1):41-60
The molecular structure of 1,1-bis(trimethylsilylethynyl)cyclopropane has been studied by the gas electron diffraction method, by vibrational spectroscopic methods and by ab initio calculations at the RHF and MP2 levels. A scaled quantum-chemical force field was used for band assignment in the experimental IR (4000-100 cm−1) and Raman (4000-200 cm−1) spectra. The root-mean-square vibrational amplitudes and harmonic shrinkage corrections were calculated taking into account non-linear relations between Cartesian and internal vibrational coordinates at the level of first-order perturbation theory (h1) and with the use of the traditional scheme (h0). 相似文献
137.
138.
IntroductionMicellarelectrokineticchromatography (MEKC)wasinventedtoextendtheutilityofcapillaryelectrophoresis(CE)andpermittedtheseparationandanalysisofneutralcompounds .ButjustlikeothermodesofCE ,MEKCarehamperedbythelowconcentrationsensitivityoftheultra … 相似文献
139.
《Operations Research Letters》2022,50(1):1-7
Fisher linear discriminant analysis is a well-known technique for dimensionality reduction and classification. The method was first formulated in 1936 by Fisher. In this paper we concentrate on three different formulations of the multi-dimensional problem. We provide a mathematical explanation why two of the formulations are equivalent and prove that this equivalency can be extended to a broader class of objective functions. The second contribution is a rate of convergence of a fixed point method for solving the third model. 相似文献
140.
本文利用电感耦合等离子体原子发射光谱多色仪的扫描功能,用卡尔曼滤波法对各种光谱干扰进行校正。结果表明,该法能处理各种类型光谱干扰,不需要样品基体匹配,其测定回收率明显优于在峰法和离峰法,具有简便、准确等优点。 相似文献