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排序方式: 共有114条查询结果,搜索用时 11 毫秒
1.
The Ramanujan Journal - This paper provides elementary proofs for several types of congruences involving multipartitions and self-convolutions of the divisor function. Our computations use... 相似文献
2.
Bhaskar Garg Shiou-Ling Lei Shou-Ching Liu Tanuja Bisht Jen-Yu Liu Yong-Chien Ling 《Analytica chimica acta》2012
The time-of-flight secondary ion mass spectrometry (TOF-SIMS) has emerged as a powerful tool for the unswerving detection of biomolecules, in particular, proteins and peptides. To date, there is very little information available on the direct determination of trimethyl/triethyl amines using TOF-SIMS. One major hurdle in this regard is an ultrahigh vacuum system, usually needed in TOF-SIMS, which hampers its usability to trimethyl/triethyl amines owing to their high evaporation rate. We designed an efficient and sensitive protocol for rapid identification and sensitive determination of tertiaryalkyl amines using TOF-SIMS. The amines were derivatized by reaction with 1,4-butane sultone and sulphuric acid sequentially to afford the corresponding sulphonic acidic ionic liquids (ILs). The TOF-SIMS analysis of these task-specific ILs (TSILs) was carried out in both positive and negative polarity. The positive ion mass spectra of TSILs showed sharp fragmented peaks for tertiaryalkyl amines at typical level and up to 10 ppm. The possible mechanism for different fragmentation pathways in positive polarity was discussed. 相似文献
3.
2-Arylazo-5,5,10,10,15,15,20,20-octamethylcalix[4]pyrroles (azo-OMCPs) have been synthesised by the reaction of calix[4]pyrrole with aryldiazonium chloride in 15–45% yields. The solution-state binding studies of the synthesised hosts were investigated by absorption spectroscopy and 1H NMR in DMSO and CDCl3, respectively. These receptors, appended with electron-donating and electron-withdrawing groups, displayed enhanced affinity and selectivity for fluoride anion. Well-defined colour change in the visible region of the spectrum was observed upon addition of fluoride ion in DMSO solution of azo-OMCPs. Detailed NMR studies in CDCl3 revealed that azo-OMCPs with nitro and chloro groups have higher binding affinity for fluoride ion. 相似文献
4.
The excellent properties of Methyl Ammonium Lead Iodide (MAPI) have already created an extensive research interest in photovoltaic applications. However, their utility in thermoelectric application is still not realized thoroughly by researchers. By continuing this interest, we have explored the formation of low dimensional CH3NH3PbI3 (MAPI) perovskite in presence of Polyaniline (PANI) and Multi-Walled Carbon Nanotubes (MWCNT) and its thermoelectric performance. For this purpose, a two stage, in-situ synthesis method was developed to prepare various composites such as MAPI-PANI, MWCNT-MAPI and MWCNT-PANI-MAPI. The as-formed MWCNT-PANI-MAPI composite revealed p-type conductivity with enhanced ZT (up to ~20,000 times) and power factor (3000 times) at room temperature as compared to pristine MAPI sample. Finally, we have demonstrated a proto-type thermoelectric power generator (TE device) fabricated using the best performing composite sample and measured its power output and efficiency at varied δT. 相似文献
5.
6.
Umakanta Tripathy R. Justin Rajesh Prem B. Bisht A. Subrahamanyam 《Journal of Chemical Sciences》2002,114(6):557-564
The excited state absorption cross-section of 5,5′-dichloro-11-diphenyl-amino-3,3′-diethyl-10, 12-ethylinethiatricarbocyanine
perchlorate (IR140) have been measured by using a single beam transmission technique. Z-scan experiments have been used to find out a few nonlinear
parameters. The excited state relaxation times have also been measured by using laser induced transient grating (LITG) technique. 相似文献
7.
Dual electrodynamics and corresponding Maxwell’s equations (in the presence of monopole only) are revisited from dual symmetry
and accordingly the quaternionic reformulation of field equations and equation of motion is developed in simple, compact and
consistent manner. 相似文献
8.
B. C. Chanyal P. S. Bisht O. P. S. Negi 《International Journal of Theoretical Physics》2011,50(6):1919-1926
Starting with the usual definitions of octonions and split octonions in terms of Zorn vector matrix realization, we have made
an attempt to write the consistent form of generalized Maxwell’s equations in presence of electric and magnetic charges (dyons).
We have thus written the generalized potential, generalized field, and generalized current of dyons in terms of split octonions
and accordingly the split octonion forms of generalized Dirac Maxwell’s equations are obtained in compact and consistent manner.
This theory reproduces the dynamic of electric (magnetic) in the absence of magnetic (electric) charges. 相似文献
9.
Dr. Ranjana Bisht Dr. Mihai V. Popescu Dr. Zhen He Ameer M. Ibrahim Dr. Giacomo E. M. Crisenza Prof. Dr. Robert S. Paton Prof. Dr. David J. Procter 《Angewandte Chemie (International ed. in English)》2023,62(29):e202302418
Benzothiophenes, activated by oxidation to the corresponding S-oxides, undergo C−H/C−H-type coupling with phenols to give C4 arylation products. While an electron-withdrawing group at C3 of the benzothiophene is important, the process operates without a directing group and a metal catalyst, thus rendering it compatible with sensitive functionalities—e.g. halides and formyl groups. Quantum chemical calculations suggest a formal stepwise mechanism involving heterolytic cleavage of an aryloxysulfur species to give a π-complex of the corresponding benzothiophene and a phenoxonium cation. Subsequent addition of the phenoxonium cation to the C4 position of the benzothiophene is favored over the addition to C3; Fukui functions predict that the major regioisomer is formed at the more electron-rich position between C3 and C4. Varied selective manipulation of the benzothiophene products showcase the synthetic utility of the metal-free arylation process. 相似文献
10.
Surendra S. Bisht 《Tetrahedron letters》2007,48(7):1187-1189
An efficient synthesis of 4-(butenolide-5-methylidenyl)-1,4-dihydropyridines has been achieved via a three-component reaction of β-keto esters or ketones, ammonium acetate and vinylic aldehydes from ascorbic acid in the presence of tetrabutylammonium hydrogen sulfate in ethylene glycol. 相似文献