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排序方式: 共有515条查询结果,搜索用时 31 毫秒
21.
Masoud Behzad Karel Samec Sang-In Bak Yacine Kadi Claudio Tenreiro Seung-Woo Hong Jong-Seo Chai 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(2):1001-1006
A worldwide challenge in the near future will be to find a way of producing radioisotopes in sufficient quantity without relying on research reactors. The motivation for this innovative work on targets lies in the accelerator-based production of radioisotopes using a neutron converter target as in the transmutation by adiabatic resonance crossing concept. Thermal analysis of a multi-channel helium cooled device is performed with the computational fluid dynamics code CFX. Different boundary conditions are taken into account in the simulation process and many important parameters such as maximum allowable solid target temperature as well as uniform inlet velocity and outlet pressure changes in the channels are investigated. The results confirm that the cooling configuration works well; hence such a solid target could be operated safely and may be considered for a prototype target. 相似文献
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Supercapacitors, or electrochemical capacitors, are a power storage system applied for harvesting energy and delivering pulses during short periods of time. The commercially available technology is based on charging an electrical double-layer (EDL), and using high surface area carbon electrodes in an organic electrolyte. This review first presents the state-of-the-art on EDL capacitors, with the objective to better understand their operating principles and to improve their performance. In particular, it is shown that capacitance might be enhanced for carbons having subnanometric pores where ions of the electrolyte are distorted and partly desolvated. Then, strategies for using environment friendly aqueous electrolytes are presented. In this case, the capacitance can be enhanced through pseudo-faradaic contributions involving i) surface functional groups on carbons, ii) hydrogen electrosorption, and iii) redox reactions at the electrode/electrolyte interface. The most promising system is based on the use of aqueous alkali sulfate as electrolyte allowing voltages as high as 2 V to be reached, due to the high overpotential for di-hydrogen evolution at the negative electrode. 相似文献
24.
Dr. Yang Chen Dr. Elzbieta Trzop Jesse D. Sokolow Prof. Dr. Philip Coppens 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(49):16651-16655
The structures of three newly synthesized phosphonate‐substituted polyoxotitanates are reported. The Ti/O core of [Ti4O(OEt)12(PhenylPO3)] ( 1 ) is the building block for two larger phosphonate‐substituted nanoclusters, [Ti25O26(OEt)36(PhenylPO3)6] ( 2 ) and [Ti26O26(OEt)39(PhenylPO3)6]Br ( 3 ). All compounds exhibit a not previously recognized triply bridging binding mode of the phosphonate anchor with short connecting Ti? O bonds, the average of which is 2.010(7) Å. Comparison with previously reported work suggests that the binding mode of the phosphonate anchor is strongly dependent on the structure of the underlying substrate. 相似文献
25.
This paper describes a novel approach to detect Cd(II) using the combination of the differential pulse anodic stripping voltammetry and magnetic nanoparticle based dispersive solid phase microextraction as an efficient, green and accurate method. Currents of Cd(II) increased linearly in the range from 75 to 2000 ng L−1 Cd(II) with a detection limit of 21.6 ng L−1. The RSD values of 2.6 and 6.0 % for 1.00 and 0.10 μg L−1 respectively showed that proposed method has an acceptable repeatability. Recovery values between 92.3 and 98.6 % showed that this approach can be successfully used for determination of Cd(II) in water samples. 相似文献
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Dr. Vibe B. Jakobsen Dr. Elzbieta Trzop Dr. Laurence C. Gavin Emiel Dobbelaar Dr. Shalinee Chikara Dr. Xiaxin Ding Dr. Kane Esien Dr. Helge Müller-Bunz Dr. Solveig Felton Dr. Vivien S. Zapf Prof. Eric Collet Prof. Michael A. Carpenter Prof. Grace G. Morgan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13407-13414
Domain wall motion is detected for the first time during the transition to a ferroelastic and spin state ordered phase of a spin crossover complex. Single-crystal X-ray diffraction and resonant ultrasound spectroscopy (RUS) revealed two distinct symmetry-breaking phase transitions in the mononuclear Mn3+ compound [Mn(3,5-diBr-sal2(323))]BPh4, 1. The first at 250 K, involves the space group change Cc→Pc and is thermodynamically continuous, while the second, Pc→P1 at 85 K, is discontinuous and related to spin crossover and spin state ordering. Stress-induced domain wall mobility was interpreted on the basis of a steep increase in acoustic loss immediately below the the Pc-P1 transition 相似文献
28.
A hybrid PDMS/glass microfluidic system for evaluation of the efficiency of photodynamic therapy is presented. 5-aminolevulinic acid (ALA) was used as a precursor of photosensitizer. The geometry of the microdevice presented in this paper enables to test different concentrations of the photosensitizer in a single assay. The viability of the A549 cells was determined 24 h after PDT procedure (irradiation with light which induced a photosensitizer accumulated in carcinoma cells, λ = 625 nm). The presented results confirmed the possibility to perform the photodynamic therapy process in vitro in microscale and the possibility to assess its effectiveness. Moreover, because two identical microstructures on a single chip were performed, the microchip can be used for examination simultaneously various cell lines (carcinoma and normal) or various photosensitizers. 相似文献
29.
Derk Brouwer Birgit van Duuren-Stuurman Markus Berges Elzbieta Jankowska Delphine Bard Dave Mark 《Journal of nanoparticle research》2009,11(8):1867-1881
In the past few years, an increasing number of studies on workplace air measurements on manufactured nano-materials and -objects
have been published. Most of the studies had a more explorative character, so a direct interpretation to workers” exposure
for a given exposure situation, activity, or process is not a straight-forward process. In general, the studies use a quite
similar package of devices for near real-time monitoring of particle number- and mass concentration in size ranges <100 nm
up to 10 μm, and the collection of samples for off-line characterization of air samples. Various approaches for addressing
background concentrations and its use to indicate the potential for exposure to nano-objects could be observed. Within the
EU-sponsored NANOSH project, a harmonized approach for measurement strategy, data analysis and reporting was developed. In
addition to time/activity–concentration profiles as reported by most studies, this approach enables a first step to estimate
the potential for exposure to manufactured nano-objects, more quantitatively. The NANOSH data will be collated into a base,
which may form the starting point for a harmonized database facilitating overall analysis in near future, to derive estimates
for exposure for several exposure situations. 相似文献
30.