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551.
P.M. Vinaya Teja Ch. RajyasreeS.B. Murali Krishna Ch. TirupataiahD. Krishna Rao 《Materials Chemistry and Physics》2012
Transparent glasses 40Sb2O3–20ZnF2–(40 − x)GeO2:xCuO, and 40Bi2O3–20ZnF2–(40 − y)GeO2:yCuO with x = 0, 0.6 and 0 ≤ y ≤ 1 wt% were prepared by melt quenching technique and were characterized by XRD and differential thermal analysis. Spectroscopic studies like optical absorption, FTIR, Raman, EPR and dielectric parameters (such as ?′, loss(tan δ), and σac) were carried out to examine the modifier and dopant effect on zinc germanate glass network. Optical absorption and EPR data have revealed that the environment of Cu2+ ions is more ionic in bismuth series rather than antimony glasses. Reduced bismuth ions have been found in pure and at lower concentration of dopant in Bi2O3 mixed glasses, which are useful for IR amplifications. FTIR and Raman spectra have indicated the conversion of GeO4 to GeO6 structural units by forming cross linking bonds like Bi–O–Ge, Ge–O–Cu, etc., and open the glass network with integration of Bi2O3 and CuO doping. It is also confirmed by decreasing Tg and Eg values. The temperature dependence of dielectric parameters at different frequencies was interpreted in terms of structural changes in the glass network. 相似文献
552.
M. V. Subbarao Darshan C. Kundaliya R. G. Kulkarni S. K. Malik W. B. Yelon 《Journal of Superconductivity and Novel Magnetism》2001,14(3):397-403
We have investigated the effect of Fe substitution on the structural and superconducting properties of La2.5Y0.5CaBa3(Cu1?x Fe x )7O z system by Rietveld refinement of the neutron diffraction patterns of three samples with x = 0.02 (labelled B1), x = 0.06 (B2), and x = 0.10 (B3) along with X-ray diffraction, resistivity, AC susceptibility, and oxygen-content measurements. Samples B1, B2, and B3 are superconducting with T c R=0 values of 73, 62, and 41 K, respectively. Neutron diffraction studies confirm (i) the formation of a single phase tetragonal structure (space group P4/mmm) for all three samples, (ii) Ca and Y ions substitution at the La site concomitantly displaces La onto Ba sites, and (iii) increasing x from 0.02 to 0.10 increases oxygen content (the amount of oxygen per unit cell), as well as Cu(1)— O(4) and Cu(1)— O(1) bond lengths whereas Cu(2)— O(4) bond length decreases with corresponding decrease in T c to 41 K due to increasing occupancy of Fe ions at Cu(2) site. The change in bond lengths with oxygen content are essentially the same as those of Fe content (x). Present studies establish a correlation between the bond lengths (Cu(1)— O(1), Cu(1)— O(4), and Cu(2)— O(4)) and the measured T c values of three samples. 相似文献
553.
Productivity of a manipulator depends, largely, on the time it takes to traverse a path, which is a function of the capacity of the actuators to produce torque. Increasing the torque capacity of the actuators to reduce path traversal time may be unrealistic in many cases. Therefore, this article studies the effects of the manipulator location, within a workcell, on the path traversal time. The article defines the boundaries of the manipulator base locus when the end‐effector path is prescribed. Effects of joint mechanical limits and obstacles on this locus are also considered. The proposed algorithm uses nonlinear programming to search the manipulator base locus for the base location that yields the minimum time to traverse a path, subject to the actuator torque constraints of the manipulator. Detailed examples are included. ©1999 John Wiley & Sons, Inc. 相似文献
554.
555.
Soon Sam Kim Masih Jorat Gerald Voecks Andras Kuthi Subbarao Surampudi Ronald L. Kent 《American Institute of Chemical Engineers》2020,66(4):e16880
A scaled-up dielectric barrier discharge (DBD) reactor has been developed and demonstrated for the production of hydrogen from steam methane reforming (SMR) by catalytic nonthermal plasma (CNTP) technology. Compared to SMR, CNTP offers conversion at ambient pressure (101.325 kPa), low temperature with better efficiency, making it suitable for distributed hydrogen production with small footprint. There have been several lab-scale DBD reactors reported in the literature. Dimension of the scaled-up DBD reactor is about six times the lab-scale version and can produce 0.9 kg H2/day. The scale-up is, however, nonlinear; several technical innovations were required including spray nozzle for homogeneous introduction of steam, perforated tube central electrodes for generation of homogeneous plasma. Conversion efficiency of the scaled-up DBD reactor is 70–80% at 550°C and 500 W. A continuous run of 8 hr was demonstrated with typical product gas composition of 69% H2, 6% CO2, 15% CO, 10% CH4. 相似文献
556.
Vadiraj Kurdekar Saranya Giridharan Jasti Subbarao Mamatha B. Nijaguna Jayaprakash Periasamy Sanjana Boggaram Amol V. Shivange Gayathri Sadasivam Muralidhara Padigaru Vijay Potluri Ashok R. Venkitaraman Dr. Kavitha Bharatham 《ChemMedChem》2019,14(18):1620-1632
The tandem BRCT domains (tBRCT) of BRCA1 engage phosphoserine-containing motifs in target proteins to propagate intracellular signals initiated by DNA damage, thereby controlling cell cycle arrest and DNA repair. Recently, we identified Bractoppin, the first small-molecule inhibitor of the BRCA1 tBRCT domain, which selectively interrupts BRCA1-mediated cellular responses evoked by DNA damage. Here, we combine structure-guided chemical elaboration, protein mutagenesis and cellular assays to define the structural features responsible for Bractoppin's activity. Bractoppin fails to bind mutant forms of BRCA1 tBRCT bearing K1702A, a key residue mediating phosphopeptide recognition, or F1662R or L1701K that adjoin the pSer-recognition site. However, the M1775R mutation, which engages the Phe residue in the consensus phosphopeptide motif pSer-X-X-Phe, does not affect Bractoppin binding, confirming a binding mode distinct from the substrate phosphopeptide binding. We explored these structural features through structure-guided chemical elaboration and characterized structure–activity relationships (SARs) in biochemical assays. Two analogues, CCBT2088 and CCBT2103 were effective in abrogating BRCA1 foci formation and inhibiting G2 arrest induced by irradiation of cells. Collectively, our findings reveal structural features underlying the activity of a novel inhibitor of phosphopeptide recognition by the BRCA1 tBRCT domain, providing fresh insights to guide the development of inhibitors that target protein–protein interactions. 相似文献
557.
558.
G. Lakshminarayana R. Subbarao Y. Sita Rama Sastry T. Chandrasekhara Rao Vijay Kale P. Vijayalakshmi 《Journal of the American Oil Chemists' Society》1982,59(5):238-240
The composition (wt %) of the fatty acids obtained by decomposition of castor oil fatty acid estolides and distillation was
determined by a combination of spectroscopic (ultraviolet, nuclear magnetic resonance, infrared), chromatographic (thin layer
on Silica Gel G modified with silver nitrate and ammonium hydroxide, gas liquid) and chemical (partial reduction and periodate/permanganate
oxidation) techniques and found to be 16:0, 2.7; 18:0, 2.6; 18:1, 5.2; conjugatedcis,trans (trans,cis)-18:2, 34.4; conjugatedcis,cis-18:2, 9.7; conjugatedtrans,trans-18:2, 3.9; 9-cis,12-trans-18:2, 20.8; 9-trans,12-cis-18:2, 2.3; and 9-cis,-18:2, 18.4. 相似文献
559.
This article addressed a broad research methodology for the development of low cost ceramics to serve as functional supports for dense metal composite membranes. The experimental challenge of this study is to work with laboratory fabricated supports characterized with lower combinations of average pore size (50–70 nm) and lower effective porosity (0.012) and hence lower surface area for activation and plating reaction. Apart from fabrication parameters, the research emphasis has been towards ensuring morphological fitness of the ceramic support, good corrosion resistance and continuous enhancement in pore densification during prolonged nickel electroless plating of about 24 h. Surface and physical characterization using LPSA, BET, FTIR, XRD, FESEM and nitrogen permeation techniques yielded valuable insights. It has been observed that the sonication of the raw membrane support in alkaline conditions enormously contributed towards good corrosion resistance during nickel ELP. The morphological fitness of the ceramic support has been targeted by assuming a combination of Knudsen and Viscous diffusion through the membrane support and activated diffusion through the dense nickel film. Thereby the morphological fitness is ensured by evaluating whether or not nickel film nitrogen flux values are lower than the support fluxes. 相似文献
560.
S.K. Maity M.S. Rana S.K. Bej J. Ancheyta-Juárez G. Murali Dhar T.S.R. Prasada Rao 《Catalysis Letters》2001,72(1-2):115-119
Pure TiO2, ZrO2 and TiO2–ZrO2 mixed oxides are prepared by urea hydrolysis. Hydrotreating catalysts containing 12 wt% molybdenum are prepared using these oxides and characterized by BET surface area, pore volume, XRD and oxygen chemisorption. It is observed that oxides produced by the method of urea hydrolysis have higher surface area as compared to those available commercially. With increasing zirconia content in the mixed oxide, the surface area increases and a maximum value is obtained for a mixed oxide having Ti and Zr molar ratio of 65/35. XRD results indicate that mixed oxides are poorly crystalline in nature. Thiophene hydrodesulfurization, cyclohexene hydrogenation and tetrahydrofuran hydrodeoxygenation are taken as model reactions for evaluating catalytic activities. It is found that both O2 uptake and catalytic activities increase with increasing zirconia content in mixed oxide and reach maximum values for the 12 wt% Mo/TiO2–ZrO2 (65/35) catalyst. With further increases in zirconia content, O2 uptake and catalytic activities decrease and the lowest values are observed for the pure ZrO2 supported catalyst. 相似文献