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排序方式: 共有103条查询结果,搜索用时 0 毫秒
1.
S. C. Tripathi K. K. Gupta M. Bindu P. M. Gandhi 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):657-661
Present investigation describes our study on photochemical generation of uranous ions and consequent degradation of solvent in the uranium loaded 30 % Tributyl phosphate-n-dodecane-nitric acid system. Samples of 30 % TBP-n-dodecane loaded with uranium were subjected to UV photolysis at 254, 300 and 350 nm respectively. Wavelength dependent formation of U(IV) has been determined spectrophotometrically by measuring absorbance at 656 nm. Additionally, photochemical yield of U(IV) has also been estimated semi quantitatively as a function of time of photolysis. The changes in the solvent composition under different photochemical conditions have been studied by examination of comparative gas chromatographic profiles of the solvent before and after photolysis. Among the wavelength of photo irradiation studied, the yield of U(IV) was found to be optimum at 300 nm with least degradation of PUREX solvent. 相似文献
2.
ABSTRACTThis study was to investigate the piezotolerance and diversity indices of microflora of Indian white prawn (Fenneropenaeus indicus) after high pressure (HP)-treatment. Indian white prawns subjected to HP-treatments and its effect was studied up to species level and compared with unpressurized samples. The bacterium was identified by using bacterial identification schemes, biochemical tests and API kits (bioMérieux, Marcyl’Etoile, France). Diversity analysis was performed using PRIMER (Plymouth Routines in Multivariate Research) software v 5.2.2. The significant elimination of microflora was found to be proportional with the pressure level. In the case of spore formers, mere destruction was noticed after HP-treatment. Arthrobacter spp., Listeria grayi and Corynebacterium spp. were the most piezotolerant bacteria in HP-treated samples. Diversity indices revealed a significant reduction of microflora of Indian white prawn. The apparent reduction of microflora with pressure level was clearly evident from the diversity indices; moreover a diminished piezotolerance of Gram negative spoilage bacteria was also observed. 相似文献
3.
Diaper CM Sutherland A Pillai B James MN Semchuk P Blanchard JS Vederas JC 《Organic & biomolecular chemistry》2005,3(24):4402-4411
Aziridine analogues of diaminopimelic acid (DAP) have been prepared stereoselectively for the first time and evaluated as inhibitors of DAP epimerase. (2R,3S,3'S)-3-(3'-Aminopropane)aziridine-2,3'-dicarboxylate was synthesised and shown to be a reversible inhibitor of DAP epimerase with an IC(50) value of 2.88 mM. (2S,4S)- and (2S,4R)-2-(4-Amino-4-carboxybutyl)aziridine-2-carboxylic acid (ll-azi-DAP and dl-azi-DAP ) were made as pure diastereomers, and both were shown to be irreversible inhibitors of DAP epimerase. ll-Azi-DAP selectively binds to Cys-73 of the enzyme active site whereas dl-azi-DAP binds to Cys-217 via attack of sulfhydryl on the methylene of the inhibitor aziridine ring. These observations are consistent with the two base mechanism proposed for the epimerization of ll-DAP and meso-DAP by DAP epimerase. 相似文献
4.
Litty Irimpan A. Deepthy Bindu Krishnan V.P.N. Nampoori P. Radhakrishnan 《Applied physics. B, Lasers and optics》2008,90(3-4):547-556
In the present work, we have investigated the nonlinear optical properties of self-assembled films formed from ZnO colloidal
spheres by z-scan technique. The sign of the nonlinear component of refractive index of the material remains the same; however,
a switching from reverse saturable absorption to saturable absorption has been observed as the material changes from colloid
to self-assembled film. These different nonlinear characteristics can be mainly attributed to ZnO defect states and electronic
effects when the colloidal solution is transformed into self-assembled monolayers. We investigated the intensity, wavelength
and size dependence of saturable and reverse saturable absorption of ZnO self-assembled films and colloids. Values of the
imaginary part of third-order susceptibility are calculated for particles of size in the range 20–300 nm at different intensity
levels ranging from 40 to 325 MW/cm2 within the wavelength range of 450–650 nm.
PACS 81.16.Dn; 42.65.-k; 42.65.An; 42.70.-a; 42.70.Nq; 78.20.Ci 相似文献
5.
Dynamic mechanical behavior of acrylonitrile butadiene rubber/poly(ethylene‐co‐vinyl acetate) blends
Hima Varghese T. Johnson S. S. Bhagawan Seena Joseph Sabu Thomas G. Groeninckx 《Journal of Polymer Science.Polymer Physics》2002,40(15):1556-1570
The dynamic mechanical behavior of uncrosslinked (thermoplastic) and crosslinked (thermosetting) acrylonitrile butadiene rubber/poly(ethylene‐co‐vinyl acetate) (NBR/EVA) blends was studied with reference to the effect of blend ratio, crosslinking systems, frequency, and temperature. Different crosslinked systems were prepared using peroxide (DCP), sulfur, and mixed crosslink systems. The glass‐transition behavior of the blends was affected by the blend ratio, the nature of crosslinking, and frequency. sThe damping properties of the blends increased with NBR content. The variations in tan δmax were in accordance with morphology changes in the blends. From tan δ values of peroxide‐cured NBR, EVA, and blends the crosslinking effect of DCP was more predominant in NBR. The morphology of the uncrosslinked blends was examined using scanning electron and optical microscopes. Cocontinuous morphology was observed between 40 and 60 wt % of NBR. The particle size distribution curve of the blends was also drawn. The Arrhenius relationship was used to calculate the activation energy for the glass transition of the blends, and it decreased with an increase in the NBR content. Various theoretical models were used to predict the modulus of the blends. From wide‐angle X‐ray scattering studies, the degree of crystallinity of the blends decreased with an increasing NBR content. The thermal behavior of the uncrosslinked and crosslinked systems of NBR/EVA blends was analyzed using a differential scanning calorimeter. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1556–1570, 2002 相似文献
6.
Hima Rani Kalita 《Tetrahedron letters》2007,48(29):5047-5049
Cuprous iodide has been found to be a very effective catalyst for allylation of aldehydes with allyltributylstannane. The catalytic system efficiently promotes the allylation reaction in DMF to produce homoallylic alcohols in high yield. 相似文献
7.
Vijay Nair P.B. Beneesh V. Sreekumar S. Bindu Rajeev S. Menon Ani Deepthi 《Tetrahedron letters》2005,46(2):201-203
The zwitterionic species generated by the addition of dimethoxycarbene to dimethyl butynedioate is trapped by arylidenemalononitrile to yield cyclopentenone derivatives. 相似文献
8.
Bindu V. Meprathu 《Tetrahedron letters》2005,46(31):5187-5190
The synthesis and reactivity of a new IBX analogue (2-iodylphenyl)diphenyl-phosphine oxide 10 is described herein along with its analysis by single crystal X-ray diffraction. 相似文献
9.
[reaction: see text] A facile synthesis of bisformylated calix[4]arenes via ipso substitution of p-tert-butylcalix[4]arenes through treatment with hexamethylenetetramine/trifluoroacetic acid is described. Under identical conditions, p-tert-butylcalix[4]arene tetramethyl ether 4 gives proximally substituted bisformylated derivative 4a in a pinched cone conformation. 相似文献
10.
We generalize the hybrid magnetofluid model of a charged fluid interacting with an electromagnetic field to the dynamics of a relativistic hot fluid interacting with a non-Abelian field. The fluid itself is endowed with a non-Abelian charge and the consequences of this generalization are worked out. Applications of this formalism to the quark gluon plasma are suggested. 相似文献