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101.
Da-Li Zhang Hong Lu Huan-Yu Wang Xin-Qiao Li Yan-Bing Xu Zheng-Hua An Hui Wang Feng Shi Ping Wang Xiao-Yun Zhao 《中国物理C(英文版)》2017,41(5):056101-056101
The silicon-strip tracker of the China Seismo-Electromagnetic Satellite(CSES) consists of two doublesided silicon strip detectors(DSSDs) which provide incident particle tracking information.A low-noise analog ASIC VA140 was used in this study for DSSD signal readout.A beam test on the DSSD module was performed at the Beijing Test Beam Facility of the Beijing Electron Positron Collider(BEPC) using a 400–800 MeV/c proton beam.The pedestal analysis results,RMSE noise,gain correction,and intensity distribution of incident particles of the DSSD module are presented. 相似文献
102.
良好实验室规范(GLP)作为一个管理系统,已成为国际上从事非临床安全性研究和实验研究所共同遵循的规范。实施GLP的目的确保试验结果的准确性和可靠性,最重要的是实现试验数据的相互认可(MAD)。欧盟REACH法规中关于物质注册的规定,也对我国的实验室认证工作提出了更高的要求。本文就目前在国际社会上得到广泛承认和实施的经济合作与发展组织(OECD)提出的GLP原则的发展概况与我国由此转化的国家GLP系列标准,以及我国的GLP认证情况进行综述;同时将OECD GLP与ISO/IEC 17025进行比较,为相关的检测机构提供重要信息。 相似文献
103.
Many peptides and proteins, containing Nα-alkylamino acids (including proline) at the second position, are prone to intramolecular aminolysis (IA) with elimination of N-terminal dipeptide sequence as 2,5-diketopiperazines (DKP). We synthesized a series of short peptides, containing N-alkylamino acids at position 2, and studied their stability in the presence of acetic acid and amines. The presence of side chains in the second and the third amino acid residues and alkylation at Nα of the third amino acid residue slowed down IA. Nα-Alkyl residue in the first amino acid residue impeded IA only in peptides, containing three or more residues. Side chains of the first amino acids did not affect significantly the cleavage rates. Acetic acid promoted IA more strongly than aqueous ammonia, while tertiary amines were less effective. Peptides with methionine-S-oxide residues were more labile than the unoxidized analogs, suggesting intramolecular assistance of the S-oxide group in aminolysis. Surprisingly, intermediate compounds of the formula Boc–Met-MeXaa-Sar–NHR underwent rapid cleavage (endopeptolysis) upon attempted acidolytic deprotection. 相似文献
104.
Javier Tamayo-Torres Leopoldo Gutierrez-Gutierrez Antonia Ruiz-Moreno 《European Journal of Operational Research》2014
The markets in which organizations currently operate require them to use behaviour based on both exploitation strategy and exploration strategy, each of which contributes fundamental benefits for the firm’s success. Exploitation strategy attempts to obtain the maximum advantage from existing abilities, whereas exploration strategy searches for new ways for the organization to adapt. Further, since manufacturing markets are characterized by short product life, they require a high level of manufacturing flexibility, which can play a crucial role in the development of the exploitation and exploration strategies. This study analyses the relationship of manufacturing flexibility to exploitation and exploration strategies, taking into account an issue of maximum international scope: the implementation of ISO standards. In many international markets, ISO implementation is crucial in enabling organizations to be competitive. However, no consensus has been reached concerning the real benefits that these systems provide to the organizations that implement them. The main goal of our study is to analyse whether there are significant differences in the relationship of manufacturing flexibility to exploitation and exploration strategies in ISO 9001:2000 certified organizations and non-certified organizations. Our results show that most of the relationships analysed are only significant in ISO certified organizations. As an added value, the study analyses the relationship of exploitation and exploration strategies to organizational learning orientation and finds this relationship to be significant in all cases. 相似文献
105.
Danilo Sciarrone Carla Ragonese Caterina Carnovale Anna Piperno Paola Dugo Giovanni Dugo Luigi Mondello 《Journal of chromatography. A》2010,1217(41):6422-6427
The natural-like assessment of essential oils is a demanding task due to the growing trend toward adulterations. Usually chiral chromatography was used for this purpose due to the capability of assessing stereospecificity which is directly related to the enzymatic pathways of each plant species. On the other hand, the quality of an essential oil involves also the evaluation of its oxidative state, mainly connected with the age and storage conditions. In fact, some modifications in the chemical profile of the oil can occur if not properly preserved. Alterations of the components due to oxidative reactions lead to the formation of peroxides, endoperoxides and epoxides, such as ascaridole and 1,2,4-trihydroxymenthane, usually present in very low amount, formed by the oxidation of terpinen-4-ol and α-terpinene, respectively. Therefore, in the present research, the quality of Australian Tea Tree oil (Melaleuca alternifolia (Maiden & Betche) Cheel, Myrtaceae) was investigated by means of a multi heart-cut multidimensional gas chromatographic system coupled to a mass spectrometer detector and by conventional enantio-GC. The MDGC system allowed the complete separation of the compounds of interest transferred from the first column to a second dimension based on a different separation mechanism. The MS detector at the end of the second column provided the identification of the peaks with high similarity values because of their high purities after the multidimensional separation. Method validation was carried out, in order to use this procedure for routine application, monitoring the repeatability of 1D retention times and 2D peak areas, LoD and LoQ. Finally, enantiomeric ratios for chiral compounds were established to support quality data obtained. 相似文献
106.
对比分析了国内外卫星推进剂在取样方法、质量检测方法、检测指标等方面所依据标准的差异,分析了我国推进剂检测实验室依据国际标准对外星推进剂进行质量分析的能力,为推进剂检测实验室具备和提高外星推进剂质量分析的能力提出了具体的措施。 相似文献
107.
《Surface and interface analysis : SIA》2006,38(3):178-180
ISO 18118 provides guidance on the measurement and use of experimentally determined relative sensitivity factors for the quantitative analysis of homogeneous materials by Auger electron spectroscopy (AES) and X‐ray photoelectron spectroscopy (XPS). This article provides a brief summary of this International Standard. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
108.
Short-range and intermediate range structures of the sodium borate glass system were investigated using Raman spectroscopy to quantify their dependence on Na2O concentration. High-resolution spectra were collected by Raman spectroscopy using the Q-switched, second-harmonic pulse of a Nd:YAG laser as an excitation source. The system was designed for measurement of the spectra of glasses and melts up to temperatures over 1000 °C with high signal to noise ratio. Use of polarized light and the simultaneous analysis of HH and VH spectra allowed deconvolution of Raman spectra into appropriate bands with high reproducibility. The deconvoluted bands in the high-frequency region of 1100-1600 cm−1 could be assigned to the vibration modes due to the short-range structures of BO3 and BO2O− units in the glasses. The band intensity ratios showed a simple linear relationship with the molar ratio, symmetric BO3 triangle unit, N3s, to asymmetric BO2O− triangle unit, N3a, obtained from 11B-NMR results. These results allowed a quantitative measure for normalizing the spectra leading to a direct comparison of the band intensities. The ring-structures of intermediate range order, boroxol, pentaborate, tetraborate and diborate groups, could be quantified from the spectra in the middle-frequency region. Their trends with Na2O concentration showed a good consistency with 10B-NMR results and also Krogh-Moe’s model. 相似文献
109.
L. Batist A. Blazhev J. Döring H. Grawe M. Kavatsyuk O. Kavatsyuk R. Kirchner M. La Commara C. Mazzocchi I. Mukha C. Plettner E. Roeckl M. Romoli 《The European Physical Journal A - Hadrons and Nuclei》2006,29(2):175-182
The β decay of 94Pd and of the 71s isomer of 94Rh was investigated by using total γ-ray absorption techniques. Several levels in 94Rh are established, including a new low-lying isomer characterized by a half-life of 0.48(3)μs and a de-exciting transition
of 55keV. E2 multipolarity is determined for this transition by measuring the intensities of its γ-rays and the characteristic X-rays
from its electron conversion. On the basis of the measured reduced β-decay transition rates to known 94Ru levels and shell model considerations, the spin-parity of the 71s and the 0.48μs isomers of 94Rh is assigned to be (4+) and (2+), respectively. The β-decay strength distributions measured for 94Pd and the 71s isomer of 94Rh yield Q
EC values of 6700(320) and 9750(320)keV for these decays and give evidence for the population of those states below and above
the magic N = 50 gap that belong to both components of the 0g spin-orbit doublet. 相似文献
110.
In this study, a sonochemical route for the preparation of a new Hf-MIL-140A metal–organic framework from a mixture of UiO-66/MIL-140A is presented. The sonochemical synthesis route not only allows the phase-pure MIL-140A structure to be obtained but also induces structural defects in the MIL-140A structure. The synergic effect between the sonochemical irradiation and the presence of a highly acidic environment results in the generation of slit-like defects in the crystal structure, which increases specific surface area and pore volume. The BET-specific surface area in the case of sonochemically derived Zr-MIL-140A reaches 653.3 m2/g, which is 1.5 times higher than that obtained during conventional synthesis. The developed Hf-MIL-140A structure is isostructural to Zr-MIL-140A, which was confirmed by synchrotron X-ray powder diffraction (SR-XRD) and by continuous rotation electron diffraction (cRED) analysis. The obtained MOF materials have high thermal and chemical stability, which makes them promising candidates for applications such as gas adsorption, radioactive waste removal, catalysis, and drug delivery. 相似文献