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排序方式: 共有147条查询结果,搜索用时 15 毫秒
1.
CV Tomy D Pal SS Banerjee S Ramakrishnan AK Grover S Bhattacharya MJ Higgins G Balakrishnan McK Paul 《Pramana》2002,58(5-6):925-935
The weakly pinned single crystals of the hexagonal 2H-NbSe2 compound have emerged as prototypes for determining and characterizing the phase boundaries of the possible order-disorder
transformations in the vortex matter. We present here a status report based on the ac and dc magnetization measurements of
the peak effect phenomenon in three crystals of 2H-NbSe2, in which the critical current densities vary over two orders of magnitude. We sketch the generic vortex phase diagram of
a weakly pinned superconductor, which also utilizes theoretical proposals. We also establish the connection between the metastability
effects and pinning. 相似文献
2.
3.
4.
Organic halides absorbed without solvent onto sodium phenylsulfinate on alumina (1) gave phenylsulfones (2) under microwave or ultrasound activation. 相似文献
5.
Smruti Dash Kaushik Ghoshal T. R. G. Kutty 《Journal of Thermal Analysis and Calorimetry》2013,112(1):179-185
Uranium–zirconium, uranium niobium, and uranium–zirconium–niobium alloys were synthesized by the arc melting technique and their phase transition temperatures were determined using a high temperature calorimeter. Heat capacities of U–7 wt%Zr, U–7 wt%Nb, U–5 wt%Zr–2 wt%Nb, U–3.5 wt%Nb–3.5 wt%Zr, and U–2 wt%Zr–5 wt%Nb were measured using a differential scanning calorimeter in the temperature range 303–921 K. A set of self-consistent thermodynamic functions such as entropy, enthalpy, and Gibbs energy function data for these binary and ternary alloys were reported for the first time using heat capacity data obtained in this study and required literature data. 相似文献
6.
7.
Nilgün KABAY Yasemin BAYGU Metin AK zzet KARA EsraNur KAYA Mahmut DURMU Yaar G
K 《Turkish Journal of Chemistry》2021,45(1):143
The current study describes the synthesis, electrochemical, computational, and photochemical properties of octa (3-hydroxypropylthio) substituted cobalt (II) ( 4 ), copper (II) ( 5 ), nickel (II) ( 6 ) and zinc(II) ( 7 ) phthalocyanine derivatives. These novel compounds were characterized by elemental analysis,1H,13C NMR, FT-IR, UV-Vis, and MS. The redox behaviors of these metallo-phthalocyanines were investigated by the cyclic voltammetric method. The optimized molecular structure and gauge-including atomic orbital (GIAO)1H and13C NMR chemical shift values of these phthalocyanines in the ground state had been calculated by using B3LYP/6–31G(d,p) basis set. The outcomes of the optimized molecular structure were given and compared with the experimental NMR values. The photochemical properties including photodegradation and singlet oxygen generation of zinc(II) phthalocyanine were studied in DMSO solution for the determination of its photosensitizer behaviors. 相似文献
8.
Summary We study the effective electron mass at the Fermi level in Kane-type semiconductors on the basis of fourth order in effective
mass theory and taking into account the interactions of the conduction electrons, heavy holes, light holes and split-off holes,
respectively. The results obtained are then compared to those derived on the basis of the well-known three-band Kane model.
It is found, takingn-Hg1−x
Cd
x
Te as an example, that the effective electron mass at the Fermi level in accordance with fourth-order model depends on the
Fermi energy, magnetic quantum number and the electron spin respectively due to the influence of band nonparabolicity only.
The dependence of effective mass on electron spin is due to spin-orbit splitting parameter of the valence band in three-band
Kane model and the Fermi energy due to band nonparabolicity in two-band Kane model. The same mass exhibits an oscillatory
magnetic-field dependence for all the band models as expected since the origin of oscillations in the effective mass in nonparabolic
compounds is the same as that of the Shubnikov-de Hass oscillations. In addition, the corresponding results for parabolic
energy bands have been obtained from the generalized expressions under certain limiting conditions. 相似文献
9.
Numerical solution of a system of coupled non-linear integro-differential equations of Fredholm type
A method, based on a generalization of Runge-Kutta's method, is applied to a system of coupled integro-differenital equations of Fredholm type. It is shown that, under certain conditions, the related integral, containing an unknown variable, in each integro-differential equation can be approximated by a contraction operator, converging in the respective space concerned. Therefore they may be found by the method of iteration, starting from arbitrary values, and hence the given system may be solved, with a high degree of accuracy. 相似文献
10.
Separation of lignosulfonate from its aqueous solution using supported liquid membrane 总被引:2,自引:1,他引:1
Kabita Chakrabarty Prabirkumar Saha Aloke Kumar Ghoshal 《Journal of membrane science》2009,340(1-2):84-91
This paper presents an experimental and theoretical study on facilitated transport of lignosulfonate (LS) through a flat sheet supported liquid membrane using trioctylamine (TOA) as carrier and dichloroethane as diluent. The studies were carried out with various support materials and operating conditions (viz. carrier concentration, strip phase concentration, salt concentration, etc.) and their effects on the transport of LS. The results were analyzed to identify a suitable combination of support and operating condition that would yield best performance of the supported liquid membrane (SLM) in terms of fast and efficient transport of LS. The stability of the SLM was assessed in terms of loss of liquid from the pores of membrane support. The SLM is found to be stable till 10 h. Co-transport mechanism has been adopted in this work by using NaOH as the strip phase. It was observed that extraction of LS is increased with increase in concentration of NaOH up to a limiting value of 0.5 M NaOH. Difference of salt concentration between feed and strip phase considerably affect the separation process. The diffusional resistances of organic membrane (Δorg) and aqueous solution (Δaq) calculated from the permeation model, which is again a combination of three unique mechanisms viz., diffusion through a feed aqueous layer, a fast interfacial chemical reaction, and diffusion of carrier–complex through the organic membrane, are found to be 609.9 and 176.6 s cm−1, respectively. The values of the diffusion coefficient in the membrane (Dorg) and in the bulk organic phase (Dcomplex) are 1.67×10−9 and 6.68 × 10−8 m2s−1, respectively. The extraction of LS is about 90%. Nearly 43% of LS can be recovered at optimum condition. 相似文献