排序方式: 共有154条查询结果,搜索用时 15 毫秒
81.
A novel series of linear complementary hydrogen bonded complexes fashioned between p-n-alkylbenzoic acids (nBA) and m-fluorobenzoic acid (FBA) are isolated. The obtained homologous series comprising of seven mesogens are analyzed by polarizing optical microscope (POM), differential scanning calorimetry (DSC) and Fourier Transform Infra-Red (FTIR) spectroscopy. It is interesting to note the correlation between the alkyl chain length and the mesogenic phases. The order of the transitions is examined through Cox parameter, experimentally derived by thermal analysis (DSC). Optical tilt angle studies in smectic C and thermal stability factors for various phases are discussed. Birefringence study by various techniques enabled to measure the refractive index at various phase transitions. These results are compared and conferred with those obtained from conventional refractometer. Further orientational order parameter for various phases has been discussed. 相似文献
82.
Near stoichiometric and stoichiometric [CuIn(1 − x)Al(x)Se2] (CIAS) thin films are prepared by chemical bath deposition (CBD) technique. X-ray diffraction (XRD) analysis have been employed to estimate the structural properties of CBD CIAS thin films and also to identify the near stoichiometric in particular defect free Cu-poor CBD CIAS thin films as preferable solar cell absorber material. 相似文献
83.
R. Rajeswarapalanichamy G. Sudha Priyanga M. Kavitha S. Puvaneswari K. Iyakutti 《Journal of Physics and Chemistry of Solids》2014
Ab initio calculations are performed to investigate the structural stability, electronic, structural and mechanical properties of 4d transition metal nitrides TMN (TM=Ru, Rh, Pd) for five different crystal structures, namely NaCl, CsCl, zinc blende, NiAs and wurtzite. Among the considered structures, zinc blende structure is found to be the most stable one among all three nitrides at normal pressure. A structural phase transition from ZB to NiAs phase is predicted at a pressure of 104 GPa, 50.5 GPa and 56 GPa for RuN, RhN and PdN respectively. The electronic structure reveals that these nitrides are metallic. The calculated elastic constants indicate that these nitrides are mechanically stable at ambient condition. 相似文献
84.
Krishnakumar V Nagalakshmi R Kavitha P 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(11-12):2724-2729
Single crystals of pure and rare earth doped trisodium barium pentachloride dihydrate have been grown by slow evaporation solution growth. The solubility of both pure and doped forms of Na3BaCl5 x 2H2O has been estimated. Vibrational spectra were recorded to determine the symmetries of molecular vibrations. The observed Raman and infrared bands were assigned and discussed in detail. The optical transparencies of the grown crystals were tested by UV-vis spectrophotometer. 相似文献
85.
C. Kavitha 《Molecular Crystals and Liquid Crystals》2017,652(1):172-184
A hydrogen bonded complex molded between p-n-octylbenzoicacid (8BA) and m-fluorobenzoic acid (FBA) is isolated and doped with predetermined quantity of Multi Walled Carbon Nano Tube (MWCNT) in order to achieve better thermal and electrical performance. The obtained series of liquid crystal nano systems comprising of three mesogens, varying in the weight percentage of MWCNT are analyzed by Polarizing Optical Microscope (POM), Differential Scanning Calorimetry (DSC) and Fourier Transform Infra-Red (FTIR) spectroscopy. Different aspects of the MWCNT – liquid crystal combination, evaluation of MWCNT's effect on selected properties of liquid crystals which are relevant to display related applications are discussed. In addition, Frederik's transitions of MWCNT dispersed liquid crystals reveal the direct effect of bundles of MWCNT on liquid crystal reorientation. 相似文献
86.
Propagation of kink–antikink pair along microtubules as a control mechanism for polymerization and depolymerization processes 下载免费PDF全文
L.Kavitha A.Muniyappan S.Zdravkovi M.V.Satari A.Marlewski S.Dhamayanthi D.Gopi 《中国物理 B》2014,(9):556-570
Among many types of proteinaceous filaments, microtubules(MTs) constitute the most rigid components of the cellular cytoskeleton. Microtubule dynamics is essential for many vital cellular processes such as intracellular transport,metabolism, and cell division. We investigate the nonlinear dynamics of inhomogeneous microtubulin systems and the MT dynamics is found to be governed by a perturbed sine-Gordon equation. In the presence of various competing nonlinear inhomogeneities, it is shown that this nonlinear model can lead to the existence of kink and antikink solitons moving along MTs. We demonstrate kink–antikink pair collision in the framework of Hirota’s bilinearization method. We conjecture that the collisions of the quanta of energy propagating in the form of kinks and antikinks may offer a new view of the mechanism of the retrograde and anterograde transport direction regulation of motor proteins in microtubulin systems. 相似文献
87.
A. Amalin Kavitha Nikhil K. Singha 《Journal of polymer science. Part A, Polymer chemistry》2007,45(19):4441-4449
A tailor‐made polymethacrylate bearing a pendant furfuryl group was prepared by atom transfer radical polymerization (ATRP), an important method of recent advances in controlled radical polymerization. It was otherwise difficult to prepare via conventional radical polymerization, because of several side reactions involving the reactive diene functionality of the furfuryl group. Successful Diels–Alder (DA) chemistry was carried out using this reactive furfuryl group of the tailor‐made polymer as diene and a bismaleimide as a dienophile. Interestingly, the resultant material was observed to be thermoreversible as evidenced by FT‐IR and DSC studies. This example of application of a tailor‐made polymer having controlled molecular architecture and with reactive diene functionality in DA chemistry will open new possibilities to prepare newer tailor‐made reversible materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4441–4449, 2007 相似文献
88.
Dr. Moulali Vaddamanu Dr. Arruri Sathyanarayana Yamane Masaya Shohei Sugiyama Ozaki Kazuhisa Dr. Kavitha Velappan Muneshwar Nandeshwar Dr. Kyohei Hisano Osamu Tsutsumi Prof. Dr. Ganesan Prabusankar 《化学:亚洲杂志》2021,16(5):521-529
The synthesis and the luminescence features of three gold(I)-N-heterocyclic carbene (NHC) complexes are presented to study how the n-alkyl group can influence the luminescence properties in the crystalline state. The mononuclear gold(I)-NHC complexes, [( L1 )Au(Cl)] ( 1 ), [( L2 )Au(Cl)] ( 2 ), and [( L3 )Au(Cl)] ( 3 ) were isolated from the reactions between [(tht)AuCl] and corresponding NHC ligand precursors, [N-(9-acridinyl)-N’-(n-butyl)-imidazolium chloride, ( L1 .HCl)], [N-(9-acridinyl)-N’-(n-pentyl)-imidazolium chloride, ( L2 .HCl)] and [N-(9-acridinyl)-N’-(n-hexyl)-imidazolium chloride, ( L3 .HCl)]. Their single-crystal X-ray analysis reveals the influence of the n-alkyl groups on solid-state packing. A comparison of the luminescence features of 1 – 3 with n-alkyl substituents is explored. The molecules 1 – 3 depicted blue emission in the solution state, while the yellow emission (for 1 ), greenish-yellow emission (for 2 ), and blue emission (for 3 ) in the crystalline phase. This paradigm emission shift arises from n-butyl to n-pentyl and n-hexyl in the crystalline state due to the carbon-carbon rotation of the n-alkyl group, which tends to promote unusual solid packing. Hence n-alkyl group adds a novel emission property in the crystalline state. Density Functional Theory and Time-Dependent Density Functional Theory calculations were carried out for monomeric complex, N-(9-acridinyl)-N’-(n-heptyl)imidazole-2-ylidene gold(I) chloride and dimeric complex, N-(9-acridinyl)-N’-(n-heptyl)imidazole-2-ylidene gold(I) chloride to understand the structural and electronic properties. 相似文献
89.
Jauregui-Osoro M Williamson PA Glaria A Sunassee K Charoenphun P Green MA Mullen GE Blower PJ 《Dalton transactions (Cambridge, England : 2003)》2011,40(23):6226-6237
A wide selection of insoluble nanoparticulate metal salts was screened for avid binding of [(18)F]-fluoride. Hydroxyapatite and aluminium hydroxide nanoparticles showed particularly avid and stable binding of [(18)F]-fluoride in various biological media. The in vivo behaviour of the [(18)F]-labelled hydroxyapatite and aluminium hydroxide particles was determined by PET-CT imaging in mice. [(18)F]-labelled hydroxyapatite was stable in circulation and when trapped in various tissues (lung embolisation, Subcutaneous and intramuscular), but accumulation in liver via reticuloendothelial clearance was followed by gradual degradation and release of [(18)F]-fluoride (over a period of 4 h) which accumulated in bone. [(18)F]-labelled aluminium hydroxide was also cleared to liver and spleen but degraded slightly even without liver uptake (Subcutaneous and intramuscular). Both materials have properties that are an attractive basis for the design of molecular targeted PET imaging agents labelled with (18)F. 相似文献
90.
Sankaranarayanan Kavitha Ramachandran Raja Prabhu Kumar Raghavan Muralitharen Sinthu S. Mansoor Usman M. Sriram Kumar V. Madan Kumar S. Vignesh V. Malini K.M. Cherian S. Madhivanan Sankaranarayanan Karthik Natarajan Arutselvan Sundararajan Raji 《Journal of Electrostatics》2011,69(4):267-274
Clinically chemo-resistant types of cancers do not respond well to conventional therapies. To treat and enhance the efficacy of drug delivery for these cancers, we have developed an in vitro model of a combination therapy using adult human mesenchymal stem cells, electrical pulses and chemo drug. Adult Mesenchymal stem cells were used because they are similar to cancer stem cells which cause the tumor to be chemo- and radiation resistant. These cells, derived from human adult bone marrow were subjected to low voltage, long duration (200 V/cm, 40 ms and 450 V/cm, 25 ms) and high voltage, short duration (1200 V/cm, 100 μs) pulses. The effect of these voltages on the viability and proliferation ability of these cells in the presence and absence of Bleomycin (chemodrug used for treating various cancers, FDA approved in US and other respective medical agencies in other countries,) indicate the potential of transfer of this technique to clinical practice for effective electro-targeted stem cell therapy. 相似文献