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排序方式: 共有735条查询结果,搜索用时 125 毫秒
91.
92.
Paulose M Shankar K Yoriya S Prakasam HE Varghese OK Mor GK LaTempa TJ Latempa TA Fitzgerald A Grimes CA 《The journal of physical chemistry. B》2006,110(33):16179-16184
Described is the fabrication of self-aligned highly ordered TiO(2) nanotube arrays by potentiostatic anodization of Ti foil having lengths up to 134 mum, representing well over an order of magnitude increase in length thus far reported. We have achieved the very long nanotube arrays in fluoride ion containing baths in combination with a variety of nonaqueous organic polar electrolytes including dimethyl sulfoxide, formamide, ethylene glycol, and N-methylformamide. Depending on the anodization voltage, pore diameters of the resulting nanotube arrays range from 20 to 150 nm. Our longest nanotube arrays yield a roughness factor of 4750 and length-to-width (outer diameter) aspect ratio of approximately 835. The as-prepared nanotubes are amorphous but crystallize with annealing at elevated temperatures. In initial measurements, 45 mum long nanotube-array samples, 550 degrees C annealed, under UV illumination show a remarkable water photoelectrolysis photoconversion efficiency of 16.25%. 相似文献
93.
Markad SD Karanjule NS Sharma T Sabharwal SG Dhavale DD 《Organic & biomolecular chemistry》2006,4(19):3675-3680
The Johnson-Claisen rearrangement of D-gluco and L-ido-derived allylic orthoesters afforded gamma,delta-unsaturated ester that on ester reduction, epoxidation, regioselective oxirane opening by sodium azide and hydrogenation led to sugar amino alcohols--immediate precursors for 1-deoxy-homonojirimycin 3a,b, and polyhydroxylated homoazepanes 4a,b. Our synthetic approach and glycosidase inhibitory activity is reported. 相似文献
94.
95.
This paper describes the preparation and conductivity studies of polyindole–ZnO composite polymer electrolyte (CPE) with LiClO4. Polyindole–ZnO-based polymer nanocomposites were prepared by chemical method and characterized by XRD, infrared (IR), scanning
electron microscope (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The IR spectrum confirms
the intermolecular interaction between polyindole and ZnO. The significant spectral changes of polyindole and ZnO nancomposites
reveal the strong interaction between polyindole and ZnO nanoparticles. The structural morphologies of the ZnO, polyindole,
and polyindole–ZnO are obtained from SEM. The TEM image of polyindole nanocomposite shows that ZnO is embedded in polyindole
matrix. An enhanced conductivity of 4.405 × 10−7 S cm−1 at 50 °C for the CPE was determined from impedance studies. 相似文献
96.
为了能在双模态超燃冲压发动机流道方案初步论证中提供一种较快速的发动机性能计算方法,在二维N-S方程基础上,引入一维完全燃烧计算方法,提出了预估超燃冲压发动机性能的准二维计算方法。该方法能够计入激波、边界层分离等对发动机性能的影响,可在较短时间计算出整机推力、比冲性能和沿程热力学参数。通过对自由射流发动机计算,验证了此方法。并在此基础上,初步分析了燃料喷注位置和流道构型对发动机性能的影响。 相似文献
97.
Ram Shankar Pathak 《Applicable analysis》2013,92(10):1223-1236
A class of pseudo-differential operators (p.d.o.'s) associated with the general Fourier kernel studied by Hardy and Titchmarsh is defined. A symbol class T m is introduced. It is shown that the p.d.o.'s associated with the symbol are continuous linear mappings of the Braaksma and Schuitman space T(λ,μ) into itself. An integral representation of p.d.o. is obtained. Some special forms of the symbol are considered. It is shown that these p.d.o.'s and their products are bounded in certain Sobolev type space. 相似文献
98.
Shankar P. Das 《Phase Transitions》2013,86(1-3):7-19
The self-consistent mode coupling theory of glass transition is briefly reviewed. The existance of a temperature Tc, higher than the usual calorimetric glass transition temperature, across which the dynamics of the fluid becomes quite different are indicated through different experimental results. Above Tc the viscosity tends to diverge with a power law while for lower temperature this sharp transition is cutoff. Such changes in the transport properties can be understood from the self-consistent mode coupling theory. The relaxation functions predicted by the mode-coupling theory over different time scales are indicated. The models with proper wave-vector dependence are also discussed. 相似文献
99.
Kishore Karumanchi Gangadhara Bhima Shankar Nangi Subba Reddy Danda Ramadas Chavakula Raghu Babu Korupolu Kishore Babu Bonige 《Journal of heterocyclic chemistry》2019,56(9):2683-2690
A facile, cost‐effective, and commercially viable synthesis of Raltegravir Potassium ( 1 ) has been developed from 2‐(1‐amino‐1‐methyl‐ethyl)‐N‐[(4‐fluorophenyl)methyl]‐1,6‐dihydro‐5‐hydroxy‐1‐methyl‐6‐oxo‐4‐pyrimidinecarboxamide ( 9 ) with high purity and in good yields. In addition, a new approach for the synthesis of key amine intermediate ( 9 ) of Raltegravir Potassium ( 1 ) from commercially available 2‐amino‐2‐methylpropanenitrile hydrochloride ( 2 ) is also described. The key features of the synthesis are fewer synthetic steps, employing the inexpensive reagents and eco‐friendly. 相似文献
100.
Nagamani M. Jalapathi P. Shankar B. Neelamma M. Krishna T. M. 《Russian Journal of General Chemistry》2019,89(5):998-1002
A novel series of 3-amino-2,2-dialcoxy-7,7-dimethyl-5-oxo-4-phenyl-3,4,5,6,7,8-hexahydro-2H-chromene-3-carbonitriles are synthesized by oxidative difunctionalization (geminal dialkoxylation and migration of the amino group) of 2-amino-4-aryl-7,7-dimethyyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitriles in the presence of iodobenzenediacetate in water medium with excellent yields. All the newly synthesized compounds are characterized by IR, 1H and 13C NMR and Mass spectral data. The representative synthesized analogues are screened in vitro for antibacterial and antifungal activity using Gentamycin sulphate and Nystatin as standard drugs.
相似文献