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A simple method (based on Floquet theory) for obtaining the characteristic equation (and hence stability) of periodic discrete-time systems is presented. Using this method it is shown that 2-periodic controllers can be used to relocate the zeros of SISO plants. Some examples are considered to illustrate the use of 2-periodic controllers for robust control of finite gain margin problems 相似文献
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Static network-related system voltage stability margin (VSM) depends on the availability of reactive power to support the transport of real power from sources to sinks. Based on this premise, the total VAr loss is minimized in the unified OPF framework considering real and reactive power controllers, and its effect on VSM is studied. Studies are conducted on a three-bus system, the IEEE 30-bus system, and a 191-bus Indian electric power system, and their results are reported. 相似文献
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Anjana Bhattacharya Jagannath Das Swapan Mitra Sisir K. Roy 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1992,54(4):399-407
Silicoaluminophosphate (SAPO-5) molecular sieves have been synthesised from reaction mixtures having a molar composition of: 0.7–1.0 Al2O3:0.7–1.0 P2O5:0.01–2.0 SiO2:xR:40 H2O (where R = (C2H3)3N or (C2H3)4NOH and x = 1.5–2.5 for (C2H5)5N and 0.5 for (C2H5)4NOH, at 473 K using various sources of alumina and silica. The effects of (i) varying the crystallinity of the alumina source (boehmite) and (ii) the use of different silica sources such as freshly prepared silica either from sodium silicate or paddy husk extract, silica gel from commercial water-glass, and tetraethyl orthosilicate have been studied. The crystallinity of boehmite has been found to have a strong effect on its reactivity towards the formation of SAPO-5. The activity of boehmite for SAPO-5 formation increased with a decrease in its crystallinity (or with increase in its moisture content). Any silica source devoid of sodium ions could be employed for the synthesis of SAPO-5. The process of crystallisation started as early as within 1.5 h of reaction and incorporation of silicon into the AlPO4 framework has been noted at this stage. Formation of some tridymite phase as impurity has been observed under conditions such as (i) SiO2 concentration > 1.7 mole and (ii) x > 2.0 when R = (C2H5)3N. 相似文献
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A reverse phase high-performance liquid chromatography method for the quantitation of sulfacetamide, sulfadiazine, sulfamerazine, and sulfamethazine in various combinations has been developed. The method is simple, accurate, precise and reproducible. The percent relative standard deviations based on 6 injections were 2.1, 0.6, 1.9, and 1.6 for sulfacetamide, sulfadiazine, sulfamerazine, and sulfamethazine, respectively. The ratio of peak heights (drug/internal standard) wer closely related (r value 0.99 or better) to concentrations (± 20% of the standard solution concentrations). The results of synthetic mixtures showed quantitative recovery and method was successfully applied to commercial dosage forms (tablets and suspension). Extraction of sulfa drugs from the dosage forms required a very simple procedure. 相似文献
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Debasmita Das Purabi Rani Samaddar Pratik Kumar Sen Kaushik Das 《Journal of Applied Electrochemistry》2008,38(6):743-749
Galvanostatic steady state current potential measurements were carried out for oxidation of a series of aliphatic alcohols
having varying number of hydroxyl groups. The anodically deposited layer of MnO2 on platinum was used as the electrode material. The deposit was characterised by scanning electron microscopy (SEM), energy
dispersive X-ray analysis (EDAX) and electrode potential measurements. The catalytic role of MnO2 in the electro-oxidation of alcohols was indicated by the chronopotentiograms and the cyclic voltammograms. An analysis of
the electrochemical data indicated a catalytic EC mechanism in which Mn (V) is generated electrochemically and consumed chemically
in succession. Based on this and the hydrogen bonding interaction between alcoholic hydroxyl groups and MnO2 layer, a mechanism was proposed which accounts for the variation in the observed electrochemical reaction orders. Tafel behaviour
was found to be followed only approximately. Current efficiency of the electrochemical oxidation of polyols was studied. Replacement
of platinum by carbon as current collector was found to leave the electrocatalytic activity of the MnO2 deposit practically unaltered. 相似文献