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排序方式: 共有194条查询结果,搜索用时 15 毫秒
1.
A. Hotzel P. Thirolf Ch. Ender D. Schwalm M. Mutterer P. Singer M. Klemens J. P. Theobald M. Hesse F. Gönnenwein H. v. d. Ploeg 《Zeitschrift für Physik A Hadrons and Nuclei》1987,356(3):299-308
The γ-ray spectrum of 252Cf(sf) was measured in the Darmstadt-Heidelberg Crystal Ball spectrometer, with a double ionization chamber mounted inside to detect the fission fragments. The measurement was aimed at a better understanding of an unusual component found in the high-energy region between 3 and 8 MeV, with fragment mass splits near symmetry. This component was proved to be predominantly emitted by the heavier fragment, to reach its highest intensity at a fragment mass split of 132:120, and to have an almost isotropic angular distribution. Calculations with the statistical code CASCADE could reproduce the main features. 相似文献
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H. Yücel H. Karadeniz M. A. Çetiner H. Demirel Ş. Turhan 《Journal of Radioanalytical and Nuclear Chemistry》2003,258(2):445-447
The sorption behavior of 235U fission fission products 99Mo and 132Te was studied through batch and dynamic experiments when they were dissolved in 1 to 7M HNO3 solutions. It was found that 99Mo is always totally adsorbed on hydrated SnO2, while 132Te is rather weakly adsorbed, therefore they can be separated from each other although 132Te in the solution still remains contaminated with other radionuclides as well as 99Mo does in the solid. 相似文献
5.
Ibrahim Isildak Murat Yolcu Omer Isildak Nadir Demirel Giray Topal Halil Hosgoren 《Mikrochimica acta》2004,144(1-3):177-181
Two diaza-crown ether compounds were synthesized and evaluated as Ag+-selective carriers in polyvinylchloride (PVC) membrane electrodes of solid-state type. The all-solid-state PVC membrane electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 exhibited a super-Nernstian response (75±10mV per decade) over the concentration range of 1×10–1 to 7×10–6M of Ag+ ion and a detection limit of 3×10–6M, at a wide range of pH (pH 4–7). The response time of the electrode was fast (less than 10s), and it can be used for three months without any significant deviation in potential. The proposed all-solid-state PVC membrane electrodes revealed high selectivity toward Ag+ ion with respect to alkali, alkaline earth, heavy and transition metal ions. A flow-through cell of all-solid-state PVC membrane Ag+-selective electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 has also been prepared and applied for flow-injection analysis of Ag+ ion in solution. 相似文献
6.
Unsal E Durdu A Elmas B Tuncel M Tuncel A 《Analytical and bioanalytical chemistry》2005,383(6):930-937
In this study, a new affinity high-performance liquid chromatography (HPLC) stationary phase suitable for protein separation
was synthesized. In the first stage of the synthesis, uniform porous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate), poly(HEMA-co-EDM), beads 6.2 μm in size were obtained. Homogeneous distribution of hydroxyl groups in the bead interior was confirmed
by confocal laser scanning microscopy. The plain poly(HEMA-co-EDM) particles gave very low non-specific protein adsorption with albumin. The selected dye ligand Cibacron blue F3G-A (CB
F3G-A) was covalently linked onto the beads via hydroxyl groups. In the batch experiments, albumin adsorption up to 60 mg
BSA/g particles was obtained with the CB F3G-A carrying poly(HEMA-co-EDM) beads. The affinity-HPLC of selected proteins (albumin and lysozyme) was investigated in a 25 mm×4.0-mm inner diameter
column packed with CB F3G-A carrying beads and both proteins were successfully resolved. By a single injection, 200 μg of
protein was loaded and quantitatively eluted from the column. The protein recovery increased with increasing flow rate and
salt concentration of the elution buffer and decreased with the increasing protein feed concentration. During the albumin
elution, theoretical plate numbers up to 30,000 plates/m were achieved by increasing the salt concentration. 相似文献
7.
P. Arikan O. Acar R. Acar G. A. Aycik M. A. Cetiner H. Demirel N. Efe T. Golge R. Gurellier R. Kirmaz S. Tulumen H. Yucel A. Zararsiz Y. Agus 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(3):391-394
Comprehensive Quality Control (QC) and Quality Assurance (QA) Program is stated on the quality policy, organization, methods
and records for nuclear analytical laboratories which are necessary for improvement of productivity, to upgrade the performance,
credibility and reputation. The proper and complete identification of quality elements for management and technical requirements
are being written in Quality Manual as well as analytical and organizational procedures and working instructions according
to ISO 17025 standard. Technical ability of gamma, X-ray and a/b laboratories in the Center has been checked by participation
in proficiency test, critical technical variables, and quality results. Performance of quality system has been controlled
by external audit inspection, progress reports and service to clients. The present study is a framework of the model project
of IAEA, coded RER/2/004, which has resulted self-sustainable accreditation from the national body, TURKAK.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
Syariza Abdul-Rahman Edmund K. Burke Andrzej Bargiela Barry McCollum Ender Özcan 《Annals of Operations Research》2014,218(1):3-21
In this study, we investigate an adaptive decomposition and ordering strategy that automatically divides examinations into difficult and easy sets for constructing an examination timetable. The examinations in the difficult set are considered to be hard to place and hence are listed before the ones in the easy set in the construction process. Moreover, the examinations within each set are ordered using different strategies based on graph colouring heuristics. Initially, the examinations are placed into the easy set. During the construction process, examinations that cannot be scheduled are identified as the ones causing infeasibility and are moved forward in the difficult set to ensure earlier assignment in subsequent attempts. On the other hand, the examinations that can be scheduled remain in the easy set. Within the easy set, a new subset called the boundary set is introduced to accommodate shuffling strategies to change the given ordering of examinations. The proposed approach, which incorporates different ordering and shuffling strategies, is explored on the Carter benchmark problems. The empirical results show that the performance of our algorithm is broadly comparable to existing constructive approaches. 相似文献
9.
John Quigley Lesley Walls Güven Demirel Bart L. MacCarthy Mahdi Parsa 《European Journal of Operational Research》2018,264(3):932-947
We consider supplier development decisions for prime manufacturers with extensive supply bases producing complex, highly engineered products. We propose a novel modelling approach to support supply chain managers decide the optimal level of investment to improve quality performance under uncertainty. We develop a Poisson–Gamma model within a Bayesian framework, representing both the epistemic and aleatory uncertainties in non-conformance rates. Estimates are obtained to value a supplier quality improvement activity and assess if it is worth gaining more information to reduce epistemic uncertainty. The theoretical properties of our model provide new insights about the relationship between the degree of epistemic uncertainty, the effectiveness of development programmes, and the levels of investment. We find that the optimal level of investment does not have a monotonic relationship with the rate of effectiveness. If investment is deferred until epistemic uncertainty is removed then the expected optimal investment monotonically decreases as prior variance increases but only if the prior mean is above a critical threshold. We develop methods to facilitate practical application of the model to industrial decisions by a) enabling use of the model with typical data available to major companies and b) developing computationally efficient approximations that can be implemented easily. Application to a real industry context illustrates the use of the model to support practical planning decisions to learn more about supplier quality and to invest in improving supplier capability. 相似文献
10.
Ramoğlu Bahtışen Gümrükçüoğlu Abidin Çekirge Ender Ocak Miraç Ocak Ümmühan 《Journal of fluorescence》2021,31(6):1587-1598
Journal of Fluorescence - A simple microwave-assisted synthesis of nitrogen-doped carbon dots with high oxygen content (O-N-CDs) was carried out with citric acid as a carbon source and... 相似文献