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排序方式: 共有189条查询结果,搜索用时 15 毫秒
61.
Predrag B. Petrović 《International Journal of Circuit Theory and Applications》2020,48(7):1140-1153
A novel full-wave rectifier (or inverting full-wave rectifier) based on a single second-generation current controlled conveyor (CCCII) having no external passive components and diodes, conducive to IC implementation, is proposed in this paper. The circuits are capable of precisely processing the input signals of up to 30 MHz frequency, while in the situation when the circuits are operating in a voltage mode (VM), the allowed range of possible changes in the input voltage signal is ±500 mV compared with ±1 mA in the current mode (CM). In order to more fully perceive the performance of the proposed full-wave rectifier, the influence of nonidealities and parasitic impedances effects on its work was analyzed. The simulation results using 0.35-μm parameters confirm the feasibility of the proposed solutions. 相似文献
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Miloš Tanasijević Dejan Ivezić Predrag Jovančić Dobrivoje Ćatić Dragan Zlatanović 《Quality and Reliability Engineering International》2013,29(3):317-326
This article presents the model for calculating the performance of dependability for complex technical systems. According to ISO‐IEC 300, dependability is an overall indicator for the quality of service and considers simultaneously reliability, maintainability, and maintenance support. For a proper understanding of the quality of service for any technical system, it is important to define dependability performance at the level of single component as well as at the upper levels—levels of subsystems and entire system. As dependability indicators (reliability, maintainability, and maintenance support) have been defined as linguistic variables, the fuzzy max–min composition has been used for the dependability determination and integration of its indicators. A procedure for the synthesis of single components dependability performance to upper levels in complex technical system is proposed. Max–min composition is again used as a tool for fuzzy synthesis because it enables obtaining the comprehensive and synergetic effect in a process of dependability evaluation. A practical engineering example (mechanical systems at bucket wheel excavator) has been used to demonstrate the proposed dependability synthesis model. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Marija Savic Ivan Mihajlovic Predrag Djordjevic Zivan Zivkovic 《Chemical Engineering Communications》2016,203(8):1053-1061
This article presents the results of nonlinear statistical modeling of the decomposition process of sodium aluminate solution, as part of the Bayer technology for the production of alumina. Based on the data collected in 2011 and 2012 from industrial production in the Bira? Alumina Factory, Zvornik (Bosnia and Herzegovina), nonlinear statistical modeling of the industrial processes was derived. The model was developed as an attempt to define the dependence of the degree of decomposition of sodium aluminate solution as a function of the input parameters of the leaching process: caustic ratio (αk) of the solution; ratio of the crystallization; content of Na2O(caustic) in the solution; the initial temperature of the solution; the final temperature of the solution; average diameter of the crystallized seeds; and duration of the crystallization process. As a tool for statistical modeling, Adaptive Network Based Fuzzy Inference System (ANFIS) was applied. The defined model using ANFIS methodology expressed a high level of fitting, and could be used to effectively predict the degree of decomposition of the sodium aluminate solution as a function of the input process under industrial conditions. 相似文献
65.
Zorica Mojovi? Predrag Bankovi? Nata?a Jovi?-Jovi?i? An?ela Abu Rabi-Stankovi? Aleksandra Milutinovi?-Nikoli? Du?an Jovanovi? 《Journal of Porous Materials》2012,19(5):695-703
Zeolite NaX was modified by Pt and Pt/Ru nanodispersed metallic clusters. This modification was achieved by zeolite impregnation with acetylacetonate salt/acetone solution, followed by acetone evaporation and thermal decomposition of organometallic complex. Samples characterization was performed by X-ray diffraction analysis, nitrogen adsorption?Cdesorption measurements and Raman spectroscopy. The incorporation of metal into zeolite cavities induced the amorphisation of the zeolite framework on the local level. The mixture of modified zeolite and 10?wt% of carbon black, in a form of thin layer, was pasted to a glassy carbon surface by Nafion. Electrocatalytic properties of metal-modified zeolites were tested in CO electrooxidation reaction. The mutual influence between Pt and Ru atoms enhanced electroactivity of Pt/Ru-modified zeolite toward carbon monoxide electrooxidation. The behavior of untreated 13X zeolite was investigated under the same condition in order to asses the influence of the support. Gradual deactivation of 13X electrode occurred. 相似文献
66.
Marjan Karkooti Predrag Radosavljevic Joseph R. Cavallaro 《Journal of Signal Processing Systems》2008,53(1-2):73-88
Low Density Parity Check (LDPC) codes are one of the best error correcting codes that enable the future generations of wireless devices to achieve higher data rates with excellent quality of service. This paper presents two novel flexible decoder architectures. The first one supports (3,6) regular codes of rate 1/2 that can be used for different block lengths. The second decoder is more general and supports both regular and irregular LDPC codes with twelve combinations of code lengths ??648,1296,1944-bits and code rates-1/2,2/3,3/4,5/6- based on the IEEE 802.11n standard. All codes correspond to a block-structured parity check matrix, in which the sub-blocks are either a shifted identity matrix or a zero matrix. Prototype architectures for both LDPC decoders have been implemented and tested on a Xilinx field programmable gate array. 相似文献
67.
High‐pressure recovery of anthocyanins from grape skin pomace (Vitis vinifera cv. Teran) at moderate temperature 下载免费PDF全文
Predrag Putnik Danijela Bursać Kovačević Damir Ježek Ivana Šustić Zoran Zorić Verica Dragović‐Uzelac 《Journal of Food Processing and Preservation》2018,42(1)
The objective was to evaluate the influences of the high hydrostatic pressure extraction parameters on the recovery of anthocyanins from the grape skin pomace extracts (Vitis vinifera cv. Teran) under moderate temperatures. Studied parameters were: solvents (methanol and ethanol); solvent concentrations (30, 50, and 70%); pressures (300, 400, and 500 MPa); times (3, 6.5, 10 min); and temperatures (22, 26, 30 °C). Predominant anthocyanins in all extracts were malvidins (malvidin‐3‐glucoside as the main compound) representing 55.77% of overall anthocyanin content. The type of solvent did not significantly influence anthocyanin extraction yield, while decreased solvent concentration (increased solvent‐to‐water ratio) significantly improved extraction of anthocyanins. Increase of pressure enhanced extraction yield of the anthocyanins but temperature showed stronger impact on the anthocyanins recovery. This investigation evidenced that the best conditions for HHPE of anthocyanins from grape pomace were extraction time 3.39 min, extraction temperature 29.48 °C, pressure 268.44 MPa and solvent concentration 70%.
Practical applications
Due to increased interest for the use of cheap winery byproducts as a source of expensive polyphenols for functional food production, skins from grape pomace became valuable raw material. Therefore, there is a need to evaluate the influence of HHPE innovative extraction technology on its nutritive value during processing. Optimizing parameters for polyphenolic recovery from grape pomace is directly related with nutritional value and economics of food engineering during industrial processing. Obtained results showed that the HHPE under lower temperatures is suitable for the extraction process of anthocyanins from grape skin pomace, but more research is needed to identify other food‐grade solvents with their corresponding concentrations that are useful for the extraction assisted with high hydrostatic pressure. 相似文献68.
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Effects of modified atmosphere,anti‐browning treatments and ultrasound on the polyphenolic stability,antioxidant capacity and microbial growth in fresh‐cut apples 下载免费PDF全文