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排序方式: 共有1706条查询结果,搜索用时 15 毫秒
1.
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
2.
Role of nanoscale AlN and InN for the microwave characteristics of AlGaN/(Al,In)N/GaN-based HEMT 总被引:4,自引:0,他引:4
A new AlGaN/GaN-based high electron mobility transistor (HEMT) is proposed and its micro-wave characteristics are discussed by introducing a nanoscale AlN or InN layer to study the potential improvement in their high frequency performance. The 2DEG transport mechanism including various sub-band calculations for both (Al,In) N-based HEMTs are also discussed in the paper. Apart from direct current characteristics of the proposed HEMT, various microwave parameters such as transconductance, unit current gain (h 21 = 1) cut-off frequency (f t ), high power-gain frequency (f max). Masons available/stable gain and masons unilateral gain are also discussed for both devices to understand its suitable deployment in microwave frequency range. 相似文献
3.
Direct method of overmodulation with integrated closed loop stator flux vector control 总被引:1,自引:0,他引:1
Tripathi A. Khambadkone A.M. Panda S.K. 《Power Electronics, IEEE Transactions on》2005,20(5):1161-1168
Overmodulation achieves full utilization of installed dc link voltage, by modifying the magnitude and the phase of reference voltage vector. Due to the nonlinear behavior in this region, closed loop vector control becomes difficult. A simple method of overmodulation with closed loop control of stator flux vector is proposed in this paper. Instead of modifying the voltage reference by nonlinear equations or look up table, we propose a direct method to generate the switching times. In so doing, the average angular velocity of the stator flux vector is controlled linearly throughout the modulation range. The proposed method shows lower harmonic distortion compared with existing methods. It greatly reduces the complexity and cost of achieving overmodulation over existing schemes. 相似文献
4.
In this research article, a new third-order voltage-mode active-C asymmetrical band pass filter is proposed. It uses three numbers of current-controlled current conveyors and three numbers of equal-valued capacitors. The topology has the following important features: uses only three active elements, uses three capacitors, uses all grounded capacitors and no resistor is suitable for integrated circuit design, there is no matching constraint, high input impedance, low output impedance, central frequency can easily be electronically controlled by bias current, and frequency response is asymmetrical in nature. The application of the proposed topology in the realisation of a voltage-mode sixth-order symmetrical band pass filter has been demonstrated. The workability of the proposed topology and sixth-order filter has been confirmed by simulation results using 0.35-µm Austria Micro Systems complementary metal oxide semiconductor technology. 相似文献
5.
In this paper, a probe-fed rectangular microstrip patch antenna with partially reflective superstrate at terahertz frequency (600 GHz) has been analyzed and simulated. The analysis of the partially reflective surface shows the highly reflective property of the surface over the wideband of the frequencies. The analysis of a specific configuration (rectangular patch) of partially reflective surface predicts the directivity of antenna to be the order of 24 dBi and subsequently it has been validated with the simulation. The proposed antenna has been simulated by using commercially available CST Microwave Studio simulator based on finite integral technique. Next to this, the application scenario of this kind of the antenna in the terahertz regime of the electromagnetic spectrum has been discussed and it has been obtained that this antenna is capable to establish 9 m long communication link. 相似文献
6.
A number of wild plants, used by rural and tribal populations and contributing significantly to their livelihood and food security have escaped recognition and scientific inquiry. Their distribution, conservation, mode of harvest by locals and optimal use require region-specific assessment in order to integrate them into developmental interventions. This study analyzed the collection, consumption, sale and income from edible forest fruits in 49 tribal villages spread over five districts of Orissa State in eastern India. Density, dominance and diversity of species yielding wild fruit were measured by studying ecological parameters in the sample plots. We estimated an average of 48 fruit plants per hectare of deciduous forests. Fifty-six wild edible fruit species belonging to 40 genera in 26 families were recorded in the study region, many of which have multiple uses. Indigenous fruits formed part of the family diet with average annual consumption of 73 kg per household. Sale of wild fruits contributed 15 % of income for tribal households. Despite their good knowledge of indigenous fruits, the tribal populations have not adopted fruit tree farming which would enhance their nutrition and income. 相似文献
7.
8.
Influence of altitudinal variation on the antioxidant potential of tartar buckwheat of Western Himalaya 总被引:1,自引:0,他引:1
Garima Kishore Shashi Ranjan Anjana Pandey Sanjay Gupta 《Food science and biotechnology》2010,19(5):1355-1363
In the present work, the effect of altitudinal variations on the total phenol, flavonoid, and antioxidant potential of seeds
and hull of Tartar buckwheat collected from 15 different locations of Western Himalaya has been investigated. Methanolic and
acetonic extracts of seed and hull powder showed significantly increasing amounts of total polyphenol content, and antioxidant
potential with rising altitude. Methanolic extract of seed and hull powder were found to have significantly greater polyphenol,
and antioxidant potential as compared to acetonic extract. The methanolic seed extract of Inderdhara (3,133 m) showed the
maximum total phenolic content 1,651 μg gallic acid equivalent/50 mg of dry weight. The methanolic seed extract of Inderdhara
showed the maximum antioxidant activity (77.29±1.2%) and antiradical activity (55.5±0.5%) also. The results of this study
exhibited good correlation with total polyphenol and antioxidant potential in all the samples followed by the increasing tendency
towards rising altitude. 相似文献
9.
Nandita Dasgupta Shivendu Ranjan Shraddha Mundra Ashutosh Kumar 《International Journal of Food Properties》2016,19(3):700-708
The present study was carried out to fabricate the food grade vitamin E acetate nanoemulsion using edible mustard oil and to evaluate its improved bioactivities. A food-grade vitamin E acetate nanoemulsion was fabricated using the edible mustard oil and surfactant Tween-80. Flocculation was not observed for 15 days. The nanoemulsion was characterized for droplet morphology and size distribution using atomic force microscope and zetasizer, respectively. We observe a stable nanoemulsion of spherical morphology and a size distribution of 86.45 ± 3.61 nm. Further, the high-performance liquid chromatography method was used to determine the vitamin E acetate concentration and encapsulation efficiency for the stable nanoemulsion. These nanoemulsions showed improved bioactivity, antioxidant, and antimicrobial activity and could be potentially used to increase the shelf life of fruit juice. 相似文献
10.
Debapriya Mohanty Rajashree Jena Ritesh Pattnaik Swati Mohapatra Manish Ranjan Saini 《International Journal of Food Properties》2016,19(4):837-846
In recent decades, bioactive peptides have attracted increasing interest as health promoting functional foods. A variety of naturally formed bioactive peptides have been found in fermented dairy products such as yogurt, sour milk, and cheese. Initially these peptides are inactive within the sequence of the parent protein molecule and can be generated by gastrointestinal digestion of milk, fermentation of milk with proteolytic starter cultures, and/or hydrolysis by proteolytic enzymes. Milk derived peptides exert a number of health beneficial activities, even upon oral administration. Bioactive peptides have a great impact on major body systems including the digestive, nervous, endocrine, cardiovascular, diabetes type II, obesity, and immune systems. Antimicrobial peptides are also an important ingredient of innate immunity, especially at mucosal surfaces such as lungs and small intestine that are constantly exposed to a range of potential pathogens. Therefore, it plays an important role in boosting natural immune protection by reducing the risk of chronic diseases. Bioactive peptides are considered as potent drugs with well-defined pharmacological residues and also used to formulate health-enhancing nutraceuticals. 相似文献