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101.
Construction of modified inorganic mineral with controlled mineralization analogues of those produced by nature is now of
current interest for understanding the mechanism of thein vivo biomineralization processes, as well as looking for fresh industrial and technological applications. Low-molecular-weight
chiral poly-carboxylate ligands derived from naturally occurring L-α-amino acids have been used as model systems to study
the effect of molecular properties on crystal growth modification. 相似文献
102.
Avijit Pramanik Mouchumi Bhuyan Gopal Das 《Journal of photochemistry and photobiology. A, Chemistry》2008,197(2-3):149-155
The newly synthesized simple tripodal ligand tris-[2-(naphthalen-2-yloxy)-ethyl]-amine (L1) act as a fluorescence signaling system for aromatic guest. It forms inclusion complexes with several electron deficient aromatic compounds. This inclusion phenomenon has been studied by steady-state fluorescence spectroscopy and solid-state structural analysis. Electron-rich L1 shows dramatic color change and a concomitant quenching of luminescence in solution as well as solid phase when titrated with several other electron deficient aromatic guest molecules. Rather high selectivity towards the picric acid was observed. L1 simultaneously forms inclusion complex and organic salt co-crystal with the composition [(L1H+) (Pic−)] PicH (PicH = picric acid) when crystallized in the presence of picric acid. In the solid state, it forms a strong π–π, C–Hπ and C–HO type interactions. 相似文献
103.
Suman Bagchi P. Prem Kiran M. K. Bhuyan M. Krishnamurthy K. Yang A. M. Rao G. Ravindra Kumar 《Pramana》2010,75(6):1197-1202
Efficient low debris hard X-ray source based on multiwalled carbon nanotubes (MWNT) irradiated by intense, femtosecond laser
over an intensity range of 1015–1017 W cm−2 μm2 is reported. The MWNT targets yield two orders of magnitude higher X-rays (indicating significant enhancement of laser coupling)
and three orders of magnitude lower debris compared to conventional metallic targets under identical experimental conditions.
The simple analytical model explains the basic experimental observations and also serves as a guide to design efficient targets
to achieve low-debris laser plasma-based hard X-ray sources at low laser intensities suitable for multi-kHz operation. 相似文献
104.
Two iron–nitrosyl–porphyrins, nitrosyl[meso‐tetrakis(3,4,5‐trimethoxyphenylporphyrin]iron(II) acetic acid solvate ( 3 ) and nitrosyl[meso‐tetrakis(4‐methoxyphenylporphyrin]iron(II) CH2Cl2 solvate ( 4 ), were synthesized in quantitative yield by using a modified procedure with nitrous acid, followed by oxygen‐atom abstraction by triphenylphosphine under an argon atmosphere. These nitrosyl porphyrins are in the {FeNO}7 class. Under an argon atmosphere, these compounds are relatively stable over a broad range of pH values (4–8) but, under aerobic conditions, they release nitric oxide faster at high pH values than that at low pH values. The generated nitric‐oxide‐free iron(III)–porphyrin can be re‐nitrosylated by using nitrous acid and triphenylphosphine. The rapid release of NO from these FeII complexes at high pH values seems to be similar to that in nitrophorin, a nitric‐oxide‐transport protein, which formally possesses FeIII. However, because the release of NO occurs from ferrous–nitrosyl–porphyrin under aerobic conditions, these compounds are more closely related to nitrobindin, a recently discovered heme protein. 相似文献
105.
106.
The viscosity of dilute aqueous solutions of K3[AI(ox)3]·3H2O, K3[Fe(ox)3]·3H2O, K3[Co(ox)3]·3H2O, and K3[Cr(ox)3]·3H2O complexes, as well as K2(ox)·H2O, were measured between 15 and 35°C. Those of CoCl2, 6H2O, FeCl3, A12(SO4)3·18H2O, and CrCl3·6H2O were measured at 25°C. These data were analyzed by the Jones–Dole equation. The ionic B coefficients of the above complex anions were discussed in terms of ion–solvent interactions and the overall change in B associated with complex formation. 相似文献
107.
108.
109.
H. Bhuyan M. Favre G. Avaria H. Chuaqui H. Kelly A. Marquez 《Applied Surface Science》2009,255(6):3558-3562
We have performed an experimental investigation of the potential use of intense plasma jets produced in a repetitive pulsed capillary discharge (PCD) operating in methane gas, to irradiate Si (1 0 0) substrates. The surface modifications induced by the plasma jet using two different material inserts at the capillary end, graphite and titanium, are characterized using standard surface science diagnostic tools, such as scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and Raman spectroscopy (RS). It has been found that the application of methane plasma jet results in the formation of sub-micron size carbon structures. It is observed that the resulting plasma irradiated surface morphologies are different, depending on the different material inserts used at the capillary end, at otherwise identical operational conditions. To investigate the species responsible for the observed surface changes in different material inserts to the capillary, optical-emission spectroscopy (OES) was recorded using a 300-1000 nm spectrometer. The OES results show the presence of H, CH and C2 Swan band in the discharge plasma, which play a significant role in the formation of the carbon structures. 相似文献
110.
P. J. Bhuyan H. N. Borah K. C. Lekhok J. S. Sandhu 《Journal of heterocyclic chemistry》2001,38(2):491-493
The reaction of 6‐hydrazino uracils 1 and nitrones 2 result in an efficient one‐pot synthesis of pyrazolo[3,4‐d]pyrimidines 3 in excellent yields. The isolation of the by‐product aniline from the reaction mixture supported the plausible mechanism for the formation of pyrazolo[3,4‐d]pyrimidines. 相似文献