排序方式: 共有46条查询结果,搜索用时 31 毫秒
1.
Kommuri Shekarrao Partha Pratim KaishapShyamalee Gogoi Sanjib Gogoi Romesh C. Boruah 《Tetrahedron letters》2014
A facile method for the synthesis of steroidal D-ring fused pyrazolo[1,5-a]pyrimidines through a microwave mediated reaction between steroidal β-bromovinyl aldehydes and pyrazoloamines using palladium(II) catalyst has been described. 相似文献
2.
Partha Pratim Kaishap Kommuri ShekarraoPallabi Saikia Sanjib Gogoi Romesh C. Boruah 《Tetrahedron letters》2014
The preparation of steroid/nonsteroid fused benzo[b][1,4]thiazepines and 2-arylsubstituted benzo[b][1,4]thiazepines is described from Pd(OAc)2 catalyzed reaction of steroidal/nonsteroidal β-halovinyl aldehydes and 2-aminothiophenols in DMF under heating condition. 相似文献
3.
Constrained moving least‐squares immersed boundary method for fluid‐structure interaction analysis 下载免费PDF全文
A numerical method is presented for the analysis of interactions of inviscid and compressible flows with arbitrarily shaped stationary or moving rigid solids. The fluid equations are solved on a fixed rectangular Cartesian grid by using a higher‐order finite difference method based on the fifth‐order WENO scheme. A constrained moving least‐squares sharp interface method is proposed to enforce the Neumann‐type boundary conditions on the fluid‐solid interface by using a penalty term, while the Dirichlet boundary conditions are directly enforced. The solution of the fluid flow and the solid motion equations is advanced in time by staggerly using, respectively, the third‐order Runge‐Kutta and the implicit Newmark integration schemes. The stability and the robustness of the proposed method have been demonstrated by analyzing 5 challenging problems. For these problems, the numerical results have been found to agree well with their analytical and numerical solutions available in the literature. Effects of the support domain size and values assigned to the penalty parameter on the stability and the accuracy of the present method are also discussed. 相似文献
4.
[reaction: see text] The microwave-mediated three-component reaction of acyl bromide, pyridine, and acetylene is catalyzed by basic alumina to give corresponding indolizines in excellent yields in a one-pot reaction. 相似文献
5.
In this paper, we study the matrix multiplication operators on Banach function spaces and discuss their applications in semigroups
for solving the abstract Cauchy problem. 相似文献
6.
Givenf: R
n
R
n*
with some conditions, our aim is to compute a fixed pointx f(x) off; hereR
n
isn-dimensional Euclidean space andR
n*
is the collection of nonempty subsets ofR
n
. A typical application of the algorithm can be motivated as follows: Beginning with the constant mapf
0:R
n
{0} R
n
and its fixed pointx
0 = 0, we deformf
t
ast tof
f and follow the pathx
t
of fixed points off
t
. Cluster points of thex
t
's ast are fixed points off.
This research was supported in part by Army Research Office-Durham Contract DAHC-04-71-C-0041 and by National Science Foundation Grant GK-5695. 相似文献
7.
We study the boundedness and the compactness of composition operators on some Banach function spaces such as absolutely continuous Banach function spaces on a -finite measure space, Lorentz function spaces on a -finite measure space and rearrangement invariant spaces on a resonant measure space. In addition, we study some properties of the spectra of a composition operator on the general Banach function spaces.
8.
Romesh K Kaul 《Pramana》1982,19(2):183-188
Some recent developments with respect to the resolution of the gauge hierarchy problem in grand unified theories by supersymmetry
are presented. A general argument is developed to show how global supersymmetry maintains the stability of the different mass-scales
under perturbative effects. 相似文献
9.
A theoretical study of antioxidant activity of some Schiff bases derived from biologically important phenolic aldehydes and phenylenediamines 下载免费PDF全文
Romesh Borgohain Jyotirekha G. Handique Ankur Kanti Guha Sanjay Pratihar 《Journal of Physical Organic Chemistry》2018,31(2)
Because of their numerous biological as well as industrial importance, the study of Schiff bases is an emerging field for the researchers, in recent time. In this study, we have designed some Schiff bases derived from biologically important precursors. The antioxidant activities of the designed compounds are thoroughly studied theoretically using density functional theory taking various parameters like bond dissociation enthalpy, ionization enthalpy, proton dissociation enthalpy, and electron transfer enthalpy followed by the study of effects of solvent, spin density, and molecular orbital on antioxidant activity of the compounds. The comparison of antioxidant activity of the compounds with that of phenol and their parent aldehydes reveals the superior antioxidant activity of the designed compounds. This study contributes towards the information of an important bridge between bioorganic and computational chemistry. 相似文献
10.
Vaughn DD Patel RJ Hickner MA Schaak RE 《Journal of the American Chemical Society》2010,132(43):15170-15172
Narrow-band-gap IV-VI semiconductors offer promising optoelectronic properties for integration as light-absorbing components in field-effect transistors, photodetectors, and photovoltaic devices. Importantly, colloidal nanostructures of these materials have the potential to substantially decrease the fabrication cost of solar cells because of their ability to be solution-processed. While colloidal nanomaterials formed from IV-VI lead chalcogenides such as PbS and PbSe have been extensively investigated, those of the layered semiconductors SnS, SnSe, GeS, and GeSe have only recently been considered. In particular, there have been very few studies of the germanium chalcogenides, which have band-gap energies that overlap well with the solar spectrum. Here we report the first synthesis of colloidal GeS and GeSe nanostructures obtained by heating GeI(4), hexamethyldisilazane, oleylamine, oleic acid, and dodecanethiol or trioctylphosphine selenide to 320 °C for 24 h. These materials, which were characterized by TEM, SAED, SEM, AFM, XRD, diffuse reflectance spectroscopy, and I-V conductivity measurements, preferentially adopt a two-dimensional single-crystal nanosheet morphology that produces fully [100]-oriented films upon drop-casting. Optical measurements indicated indirect band gaps of 1.58 and 1.14 eV for GeS and GeSe, respectively, and electrical measurements showed that drop-cast films of GeSe exhibit p-type conductivity. 相似文献