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71.
Magdy A. Bayoumi Padma Rao Bassem Alhalabi 《The Journal of VLSI Signal Processing》1992,4(2-3):147-163
An algorithm specific architecture for Kalman filter is presented. It is based on systolic arrays. Parallelism has been exploited on both algorithm and architecture levels. Faddeev's algorithm has been employed. The involved computation tasks, triangularization and nullification are performed in parallel which leads to a speedup of about 40%. Throughput has been increased by using bi-trapezoidal arrays. Techniques have been employed for data storage and skewing which enables fast data transfer rates. A VLSI implementation of a prototype of matrix of size 4×4 has been discussed. 相似文献
72.
PR Padma B Oesch-Bartlomowicz JG Hengstler F Oesch 《Canadian Metallurgical Quarterly》1997,71(10):655-659
OBJECTIVES: Endoscopic sphincterotomy has become a generally accepted method for extracting common bile duct stones in high risk or cholecystectomized patients. However, stone extraction is impossible by the usual methods in 5 to 10% of cases. The purpose of this study was to evaluate the effect of a recently developed solvent system in patients with large bile duct stones. METHODS: Forty four patients (15 men and 29 women, median age of years) underwent contact dissolution after unsuccessful Dormia extraction. Solvents were administered via a nasobiliary catheter in 41 patients following papillotomy and through a T-tube in 3 patients. Solvent mixtures (26 mM ethylene diamine tetraacetic acid, 40 mM sodium deoxycholate and 30% dimethyl sulfoxide in an alkaline aqueous solution; and a 70/30 dimethyl sulfoxide/methyl tert-butyl ether mixture) were infused continuously and alternatively for 2 hours. RESULTS: Bile duct stones disappeared in 13-24 hours of infusion in 11 patients. In 29 patients, a clear reduction in stone volume occurred, allowing complete endoscopic extraction of the fragments. In 4 patients, the size of the stone did not change. Only mild and transient side-effects including abdominal pain (68%), nausea (72%), vomiting (52%), diarrhea and sleepiness (50%) were observed. CONCLUSION: Direct dissolution therapy could be an effective method for the non-surgical management of large bile duct stones in selected patients when intra- or extracorporeal lithotripsy is unsuccessful. 相似文献
73.
This paper determines the degradation of the rural water system in the Mekong Delta, Vietnam, due to pesticide application for rice production. The theoretical framework of the contingent valuation method is identified and its empirical application to the valuation of the rural water resources is presented via a case study in the Mekong Delta. Study results show that the loss of value of the rural water resources due to pesticide contamination in the Mekong Delta is about US$251 million. 相似文献
74.
Narayanan Gopalakrishnan Padmanabha Pillai V Shanti Cadavallur Subrahmanian Narayanan 《Journal of the science of food and agriculture》1990,50(1):111-117
Analysis of clove (Syzygium aromaticum L) bud oil extracted with liquid and supercritical carbon dioxide shows significant qualitative and quantitative compositional differences compared with oil obtained by the conventional hydrodistillation process. The parameters of pressure, temperature, contact time etc, and also the clove oil components, affect the extraction of the bud flavour from the spice. 相似文献
75.
The molten salt or the flux method is utilized in this study to fabricate a grainoriented YBa2Cu3O7−x
superconductor. The formation of YBa2Cu3O7−x
in the presence of molten salts of Na, K, Li belonging to chloride and iodide systems does not appear feasible due to the
instability of the superconducting phase in these salt systems. Studies using the “green phase,” Y2BaCuO5, as seed crystals suggest a two-stage approach in the formation of YBa2Cu3O7−x
. The process uses Y2BaCuO5 formed by molten salt synthesis which has been observed to be stable in water and against most of the salts. The 211 crystals
can be mixed with oxides and converted to 123. Analysis of X-ray data and SEM micrographs indicates a certain degree of grain
orientation, which can be further enhanced by tape-casting or not-forging. 相似文献
76.
B. K. Raghu Prasad B. H. Bharatkumar D. S. Ramachandra Murthy R. Narayanan S. Gopalakrishnan 《Canadian Metallurgical Quarterly》2005,131(8):831-838
In developing a one-dimensional analysis and design procedure for reinforced concrete structures, research is generally based on yield phenomena and the plastic flow of steel in tension and concrete in compression. The ability of concrete to resist tension is considered in the form of tension stiffening or is completely disregarded. This procedure does not account for the influence of structural size in changing the failure mode and the stress distribution across the uncracked or cracked ligament. The key factor affecting this stress distribution is found to be the strain-softening modulus. This paper presents an improved model that is based on the fundamental equilibrium equation for the progressive failure of plain concrete beams. The concrete stress-strain relationship in tension is derived by calculating the peak tensile stress and softening modulus for different depths of beams on the basis of the fracture parameters obtained with the size effect law. Thus, the proposed model uses the peak tensile stress and the softening modulus, which vary depending on the size of the beam. To study the effect of the strength of high-performance concrete (HPC) on the concrete tensile stress-strain relationship, the experimental load-deflection plots of different-sized beams are compared with those obtained by using the proposed analytical model for eight different mixes made with locally available fly ash and slag. The model is also extended for lightly reinforced concrete beams, and the results are compared with those in the literature and are found to be in good agreement. 相似文献
77.
Rajendran Babhu Vignesh Mathur Gopalakrishnan Sethuraman 《Journal of Coatings Technology and Research》2014,11(4):545-554
Protection of aluminum metal and its alloys from corrosion is a key requirement for many engineering applications. Nowadays, sol–gel coating technology is recognized as the ideal replacement for chromate conversion coatings. The present work makes use of 3-glycidoxypropyltrimethoxysilane (GPTMS) as a precursor for sol–gel coating. GPTMS was subjected to hydrolysis and subsequent condensation reaction to get a three-dimensional network and methylthiourea (MTU) was incorporated into the sol–gel matrix. MTU-doped GPTMS-based sol–gel coatings were applied over aluminum metal by dip coating method. The resultant coating was studied by FTIR, XRD and SEM. MTU-doped GPTMS-based sol–gel coatings increased the hydrophobic nature of the coating and were stable up to a temperature of 450°C. The protective nature of the coatings was evaluated in a 1% NaCl environment using electrochemical impedance and polarization studies. The study has revealed that doping of MTU enhanced the protection ability of doped GPTMS-based sol–gel coating to a significant extent. 相似文献
78.
Structure‐Guided Design of Thiazolidine Derivatives as Mycobacterium tuberculosis Pantothenate Synthetase Inhibitors 下载免费PDF全文
Parthiban Brindha Devi Ganesh Samala Jonnalagadda Padma Sridevi Shalini Saxena Mallika Alvala Elena G. Salina Prof. Dharmarajan Sriram Prof. Perumal Yogeeswari 《ChemMedChem》2014,9(11):2538-2547
The pantothenate biosynthetic pathway is essential for the persistent growth and virulence of Mycobacterium tuberculosis (Mtb) and one of the enzymes in the pathway, pantothenate synthetase (PS, EC: 6.3.2.1), encoded by the panC gene, has become an appropriate target for new therapeutics to treat tuberculosis. Herein, we report nanomolar thiazolidine inhibitors of Mtb PS developed by a rational inhibitor design approach. The thiazolidine compounds were discovered by using energy‐based pharmacophore modelling and subsequent in vitro screening, which resulted in compounds with a half maximal inhibitory concentration (IC50) value of (1.12±0.12) μM . These compounds were subsequently optimised by a combination of modelling and synthetic chemistry. Hit expansion of the lead by chemical synthesis led to an improved inhibitor with an IC50 value of 350 nM and an Mtb minimum inhibitory concentration (MIC) of 1.55 μM . Some of these compounds also showed good activity against dormant Mtb cells. 相似文献
79.
Plasmonic Nanostructures: 3D Nanostar Dimers with a Sub‐10‐nm Gap for Single‐/Few‐Molecule Surface‐Enhanced Raman Scattering (Adv. Mater. 15/2014) 下载免费PDF全文
80.
Ram Kumar K. Gopalakrishnan Irshad Ahmad C. N. R. Rao 《Advanced functional materials》2015,25(37):5910-5917
Composites of boron nitride (BN) and carboxylated graphene are prepared for the first time using covalent cross‐linking employing the carbodiimide reaction. The BN1–xGx (x ≈ 0.25, 0.5, and 0.75) obtained are characterized using a variety of spectroscopic techniques and thermogravimetric analysis. The composites show composition‐dependent electrical resistivity, the resistivity decreasing with increase in graphene content. The composites exhibit microporosity and the x ≈ 0.75 composite especially exhibits satisfactory performance with high stability as an electrode in supercapacitors. The x ≈ 0.75 composite is also found to be a good electrocatalyst for the oxygen reduction reaction in fuel cells. 相似文献