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Total organic carbon (TOC) is one of the most important parameter for the knowledge of water and wastewater quality, because it concerns theoretically all organic compounds. Unfortunately, some restrictions with respect to TOC measurement must be considered, explaining that alternative procedures have been envisaged, among which UV spectrophotometry. Starting from a comparison of results between high temperature digestion and UV photo-oxidation techniques for some specific compounds and real wastewater samples, the work shows the complementary interest of using UV spectrophotometry either directly (with multiwavelength procedures) or after UV photo-oxidation. 相似文献
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Chromatographic separation and quantification methods of tropa alkaloids were often described. In order to separate atropine from its degradation products ion-pair chromatography (IPC) has been frequently applied. Beside long equilibration times IPC often suffers from poor robustness. The aim of this study was to develop robust and simple HPLC methods for both stability testing of atropine solutions and limitation of related substances in atropine from plant material. Using a hydrophilic embedded RP18 column and a gradient elution gave baseline separation of all components. 相似文献
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The Nachtmann moments of deep inelastic scattering structure functions are required by kinematics to contain a so far neglected threshold factor which is dependent on both n and q2. Its presence significantly affects the “moment analysis” in the usual QCD phenomenology and it resolves the difficulties connected with improper threshold behavior of the “ξ-scaling” analysis of structure functions. 相似文献
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Study of normal colorectal tissue by FT-Raman spectroscopy 总被引:2,自引:0,他引:2
Andrade PO Bitar RA Yassoyama K Martinho H Santo AM Bruno PM Martin AA 《Analytical and bioanalytical chemistry》2007,387(5):1643-1648
FT-Raman spectroscopy was employed to study normal human colorectal tissues in vitro with the aim of evaluating the spectral
differences of the complex colon mucous in order to establish a characteristic Raman spectrum. The samples were collected
from 39 patients, providing 144 spectra for the statistical analysis. The results enable one to estabilish three well-defined
spectroscopic groups of non-altered coloretal tissues that were consistently checked by statistical (clustering) and biological
(histopathology) analyses: group 1 is represented by samples with the presence of epithelial layer, connective tissue papillae,
and smooth muscle tissue; group 2 comprises tissues with epithelial layer and connective tissue papillae; group 3 presented
mostly fatty and slack conjunctive tissue. The study reveals the existence of an intrinsic spectral variability for each patient
that must be considered when sampling tissues fragments to build a spectral database. This is the first step for future studies
and applications of Raman spectroscopy to optical biopsy and diagnosis of colorectal cancer. 相似文献
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Tzu-Chia Chen Mahyuddin KM Nasution Abdullah Hasan Jabbar Sarah Jawad Shoja Waluyo Adi Siswanto Sigiet Haryo Pranoto Dmitry Bokov Rustem Magizov Yasser Fakri Mustafa A. Surendar Rustem Zalilov Alexandr Sviderskiy Alla Vorobeva Dmitry Vorobyev and Ahmed Alkhayyat 《中国物理 B》2022,31(9):96401-096401
Understanding the relation between spatial heterogeneity and structural rejuvenation is one of the hottest topics in the field of metallic glasses (MGs). In this work, molecular dynamics (MD) simulation is implemented to discover the effects of initial spatial heterogeneity on the level of rejuvenation in the Ni$_{80}$P$_{20 }$MGs. For this purpose, the samples are prepared with cooling rates of $10^{10}$ K/s-$10^{12}$ K/s to make glassy alloys with different atomic configurations. Firstly, it is found that the increase in the cooling rate leads the Gaussian-type shear modulus distribution to widen, indicating the aggregations in both elastically soft and hard regions. After the primary evaluations, the elastostatic loading is also used to transform structural rejuvenation into the atomic configurations. The results indicate that the sample with intermediate structural heterogeneity prepared with 10$^{11}$ K/s exhibits the maximum structural rejuvenation which is due to the fact that the atomic configuration in an intermediate structure contains more potential sites for generating the maximum atomic rearrangement and loosely packed regions under an external excitation. The features of atomic rearrangement and structural changes under the rejuvenation process are discussed in detail. 相似文献