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排序方式: 共有335条查询结果,搜索用时 17 毫秒
1.
Darshan C. Kundaliya 《Solid State Communications》2004,131(8):489-491
The intermetallic compound, YRhAl, has been prepared and is found to be isomorphic with RRhAl (R=Pr, Nd, Gd, Ho and Tm) compounds crystallizing in the orthorhombic TiNiSi-type structure (space group Pnma). Heat capacity and electrical resistivity measurements in the He-3 temperature range reveal that this compound is superconducting with a transition temperature, Tc, of 0.9 K. The electronic specific heat coefficient, γ, and the Debye temperature are found to be 6.1 mJ/mol K and 197 K, respectively. The specific heat jump at the superconducting transition is found to be consistent with the BCS weak-coupling limit. This combined with the earlier observation of superconductivity in LaRhAl (Tc=2.4 K) having a different structure than that of YRhAl, suggests that the underlying structure is not very crucial for the occurrence of superconductivity in RRhAl series of compounds. 相似文献
2.
M K Parida Nita Sinha B Adhikary B Allanach A Alok K S Babu B Brahmachari D Choudhury E J Chun P K Das A Ghosal D Hitlin W S Hou S Kumar H N Li E Ma S K Majee G Majumdar B Mishra G Mohanty S Nandi H Pas M K Parida S D Rindani J P Saha N Sahu Y Sakai S Sen C Sharma C D Sharma S Shalgar N N Singh S Uma Sankar N Sinha R Sinha F Simonetto R Srikanth R Vaidya 《Pramana》2006,67(5):849-860
This is the report of flavor physics and model building working group at WHEPP-9. While activites in flavor physics have been
mainly focused on B-physics, those in model building have been primarily devoted to neutrino physics. We present summary of working group discussions
carried out during the workshop in the above fields, and also briefly review the progress made in some projects subsequently. 相似文献
3.
Paital AR Mitra T Ray D Wong WT Ribas-Ariño J Novoa JJ Ribas J Aromí G 《Chemical communications (Cambridge, England)》2005,(41):5172-5174
Based on a combined theoretical-experimental study, we propose that substituted m-phenylene ligands (m-N-Phi-N) can act as tuneable strong ferromagnetic couplers connecting Cu(II) ions; a new complex presenting that bridge with J close to +15 cm(-1) has been suggested and synthesized. 相似文献
4.
A reaction condition is established which determines the nature of the products in the molybdate-hydroxylamine-cyanide reaction. With hydroxylamine always used in excess, it is the hydroxyl ion concentration of the reaction mixture which plays a vital role in determining whether K4[Mo(NO)(CN)5] or K2[Mo(NO)(CN)5] is obtained exclusively. The latter product is hereby reported for the first time. Its powder diffractogram being typical of a cubic system, a gross structural characterization has been made possible. The former under aqueous, aerobic conditions yields a new product, (NMe4)2[Mo(NO)(CN)4]. 相似文献
5.
A general microcantilever surface modification method using a multilayer for biospecific recognition
The key to microcantilever surface modification technology is to selectively modify one side of a microcantilever surface with molecular recognition layers. In this paper, we report a general microcantilever modification method using a multilayer film. 相似文献
6.
Sharma M Sahu K Dube A Gupta PK 《Journal of photochemistry and photobiology. B, Biology》2005,81(2):107-113
Effect of varying extracellular pH on mode of cell death induced by photodynamic action of chlorin p6 was investigated in human colon carcinoma (Colo-205) cells. At an extracellular pH of 7.4, compared to cells treated with chlorin p6 in dark, the photodynamically treated cells showed reduction in mitochondrial membrane potential, an increase in ADP/ATP ratio (1:2) and a large percentage of cells with chromatin condensation. In contrast, when photodynamic treatment and post irradiation incubation was carried out in acidic medium (pH 6.5), total loss of mitochondrial membrane potential, a marked increase in ADP/ATP ratio (1:33) and increased damage to plasma membrane were observed. Further, cells subjected to photodynamic treatment in a medium of pH 7.4 showed twofold increase in caspase-3 activity as compared to photodynamic treatment at pH 6.5. These results suggest that chlorin p6 mediated photodynamic action induces apoptotic cell death when extracellular pH is 7.4 whereas necrosis is more predominant under condition when extracellular pH is 6.5. 相似文献
7.
Fabrication of nanoscale metallic spirals using phospholipid microtubule organizational templates 总被引:3,自引:0,他引:3
We describe the fabrication of metallic Cu spiral/helical nanostructures prepared via selective electroless metallization of a phospholipid microtubule template. The metallization template is created through selective, sequential adsorption of the oppositely charged polyelectrolytes, sodium poly(styrenesulfonate) (PSS) and poly(ethyleneimine) (PEI), onto nanoscale seams naturally occurring on the microtubule surface. A negatively charged Pd(II) nanoparticle catalyst is bound to the terminal cationic PEI layer of the multilayer film and initiates selective template metallization to form the helical Cu nanostructures. Details of the process are presented, and a mechanism and factors affecting the control of the feature critical dimensions are discussed. 相似文献
8.
Subratanath Koner Masaru TsutakeIsoroku Nagasawa Ryuichi IkedaPratap K. Saha Alok K. MukherjeeSurajit Banerjee 《Journal of Molecular Structure》2002,608(1):63-69
The complex bis-(N,N-dimethyl-1,2-ethanediamine) nickel(II) perchlorate undergoes a first-order thermochromic phase transition at ca. 476 K, changing its color from orange to red. The room temperature X-ray crystal structure determination showed that the nickel ion possesses a square-planar geometry with two five membered chelate rings, in the δλ conformation, forming the NiN4 chromophore. The broad-line 1H NMR indicates the onset of a dynamic disorder of diamine chelate rings at the phase transition temperature region, while T1 measurement of 1H affords the activation energy of the puckering metal chelate rings to be 26 kJ mol−1. The electronic spectrum revealed that a weakening of ligand field around the nickel is associated with the phase transition. 相似文献
9.
-2-Chlorostilbene undergoes uncatalyzed LiAlH4 reduction giving phenanthrene and -stilbene. An electron transfer radical mechanism is proposed. LiAlH4 induced isomerization of -stilbene produces -stilbene. 相似文献
10.
Abstract In the presence of the photosensitizer riboflavin at high fluence rates a photoproduct, most probably H2 O2 , is formed which causes negative phototaxis in the colorless flagellate Polytomella magna . The aim of this study was to find out whether H2 O2 is produced in a type I or II reaction. As has been shown, 1 O2 quenchers either do not influence the photodynamic action of riboflavin (furfuryl ethanol, DPBF, l -histidine, crocetin) or show slight quenching effects only at very high concentrations ≧ 10−2 M (DABCO, DMF, imidazole). D2 O is toxic to P. magna even in 1:1 and 1:2 mixtures with H2 O. On the other hand, the quenching effect of 1,4-benzoquinone, highly indicative for the type I pathway, is more than two orders of magnitude stronger than the one of the above mentioned 1 O2 quenchers. The results suggest that H2 O2 is produced in a type I reaction. Superoxide does not seem to be involved since superoxide dismutase does not diminish the photodynamic effect of riboflavin. 相似文献