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نویسندگان: 

نشریه: 

Electrochimica Acta

اطلاعات دوره: 
  • سال: 

    2021
  • دوره: 

    391
  • شماره: 

    -
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    38
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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بازدید 38

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نویسندگان: 

عقل آرا حسن

اطلاعات دوره: 
  • سال: 

    1381
  • دوره: 

    15
  • شماره: 

    1 (پیاپی 57)
  • صفحات: 

    35-44
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    1406
  • دانلود: 

    307
چکیده: 

پلی آنیلین به روش شیمیایی تهیه و در حلال -N متیل پیرولیدون حل شده و فیلمهایی به ضخامت 80 و 100 میکرومتر از آن تهیه شد. از دوپه شدن این فیلمها در محلولهای اسیدی (HCl) با دو غلظت متفاوت در زمانهای دوپه شدن مختلف فیلمهای پلی آنیلین رسانا بدست آمد. از این فیلم ها، صفحات مربعی شکل به ابعاد یک سانتی متر تهیه شد و از فیم های دارای ضخامت و زمان دوپه شدن یکسان به عنوان صفحات رسانا و از کاغذ آغشته به پارافین به عنوان دی الکتریک خازن استفاده شد. در این کار پژوهشی مراحل مختلف ساخت خازن پلی آنیلین رسانا، نتایج اندازه گیریها و محاسبات ظرفیت خازن ساخته شده بر اساس انتشار صفحه مانند دوپه کننده و همچنین پایداری ظرفیت آن در خلا و محیط اتمسفر گزارش شده است. از نتایج معلوم می شود که ظرفیت با افزایش زمان دوپه شدن افزایش می یابد و در مورد فیلمهای پلی آنیلین نارسانای با ضخامت کمتر زودتر به مقدار بیشینه خود می رسد. مقدار بیشینه ظرفیت در شرایط کار در این پژوهش در حدود 42 پیکوفاراد اندازه گیری شد.

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اطلاعات دوره: 
  • سال: 

    2023
  • دوره: 

    42
  • شماره: 

    5
  • صفحات: 

    1463-1470
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    9
  • دانلود: 

    0
چکیده: 

Graphene Oxide has been synthesized using Hummer’s method by the oxidation of graphite powder using reagents like potassium permanganate, Sulphuric acid, hydrogen peroxide, and distilled water at low temperatures. The filtered suspension of graphene oxide was changed to a dry powder at room temperature. Synthesized Graphene oxide was further modified by functionalizing using diamine 2,6-bis(4-aminophenoxy)benzonitrile (BAAP) by ultrasonication and reflux methodology, air-cooled mixture was washed with the equimolar ratio of ethanol and water which was dried at room temperature and followed by drying in the oven at 80 oC. The sample was characterized by Fourier transform infrared spectroscopy (FT-IR) which confirmed all required functional groups and proved the functionalization and modification of Graphene Oxide. Further, UV-Visible spectroscopy confirmed the slight reduction of graphene oxide by the redshift which is due to the chromophoric effect of diamine. X-ray diffraction also confirmed the expected d-spacing due to the covalent reduction of graphene oxide by shifting the peak position towards higher 2θ values. The cyclic voltammetry results are in a quasi-rectangular shape, due to the pseudocapacitance behaviour of diamine functionalized graphene oxide; successfully synthesised and functionalized graphene oxide showed electrochemical stability and an increase in capacitance with an increase in scan rates which is the promising property for Supercapacitance to ensure energy storage and conservation.

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    4
تعامل: 
  • بازدید: 

    174
  • دانلود: 

    0
چکیده: 

DIFFERENT SCIENTISTS HAVE TRIED TO COMBINE PETROPHYSICS, GEOPHYSICS, AND THERMODYNAMICS WITH ECONOMIC FACTORS IN ORDER TO FIND OUT THE BEST RECOVERY SCENARIO. HAVING A GOOD PRODUCTION SCENARIO AND A PROPER FIELD DEVELOPMENT STRATEGY REQUIRE TEDIOUS CALCULATIONS AND SIMULATIONS. PRESENT COMMERCIAL SIMULATORS ARE COMPLEX TO WORK WITH AND TIME-CONSUMING;  THEREFORE, HAVING AN OVERVIEW BY LESS PRIMARY DATA IS NECESSARY TO MANAGE THE FIELD AND TO OPTIMIZE THE RECOVERY. IT WAS A TRIGGER FOR RESERVOIR ENGINEERS TO DEVELOP A FAST AND RELIABLE SIMULATOR. SIMPLE PREDICTIVE MODELS, WHICH USUALLY USE MATERIAL OR ENERGY BALANCE ON A RESERVOIR TO FIND OUT ITS PERFORMANCE, ARE VERY FAST AND LOW-COST.capacitance-RESISTANCE MODEL (CRM) SHOWED EFFICIENT AS A FAST RESERVOIR SIMULATION TOOL USING FIELD-AVAILABLE DATA OF PRODUCTION AND INJECTIONS RATES. THIS APPROACH SETS A WEIGHTING FACTOR OR WELL-CONNECTIVITY PARAMETER AND A TIME-CONSTANT BETWEEN EACH PAIR OF INJECTION AND PRODUCTION WELLS ACCORDING TO THEIR HISTORY. IN THIS STUDY, A REAL CASE HAS BEEN MODELED USING CRM AND AN EFFICIENT AND OPTIMUM FIELD TIME-CONSTANT, WHICH COULD BE USED FOR ENTIRE FIELD, HAS BEEN DETERMINED USING CRM SIMULATION RESULTS. ITS ACCURACY IS VERIFIED BY COMPARING THE TOTAL OIL PRODUCTION RATE ERROR AND WELL-PAIR CONNECTIVITIES BETWEEN ORIGINAL AND OPTIMUM CASES.

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نویسندگان: 

AFZAL A. | MOUSAVI S.F. | KHADEMI M.

اطلاعات دوره: 
  • سال: 

    2010
  • دوره: 

    12
  • شماره: 

    3
  • صفحات: 

    339-346
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    729
  • دانلود: 

    0
چکیده: 

Water is one of the most vital constituents in plants. In this research, for an estimation of leaf moisture content, the variation of capacitance was employed. The variations were measured via designed and manufactured capacitive sensors. The objective of the research was to estimate leaf moisture content by measuring its capacitance for five agronomic crops. Experiments for measuring leaf capacitance were performed on maize, sorghum, capsular bean, white bean and sunflower at two frequencies of: 100 kHz and 1 MHz. The results showed that in all cases the best fitted curve for variations of the capacitance in relation to leaf moisture percentage was in the form of an exponential function namely: y= aebx (where y is capacitance, x is leaf moisture content, a is the linear coefficient, and b is the exponential coefficient). Parameters a and b for different plants of each crop and each frequency were not significantly different at 1% probability level. However, these coefficients were significantly different among different crops. Coefficients of determination were higher at 100 kHz than at 1 MHz. It was also observed that the higher the leaf moisture the more the data points scattered around the best-fit line, although the scattering was more uniform at 1 MHz.

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بازدید 729

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نویسندگان: 

SOLEIMANI M.

نشریه: 

Scientia Iranica

اطلاعات دوره: 
  • سال: 

    2006
  • دوره: 

    13
  • شماره: 

    3
  • صفحات: 

    310-315
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    448
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

Electrical capacitance Tomography (ECT) is an imaging technique that maps the electrical permittivity contrast of the object. This paper studies an image and a shape reconstruction method for ECT. For image reconstruction, a regularized Gauss-Newton method has been implemented, based on the inverse finite element technique. For shape reconstruction, a . narrow band level set method has been developed. Using experimental ECT data, a comparative study of these two techniques is the main objective of this paper.

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بازدید 448

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
اطلاعات دوره: 
  • سال: 

    2019
  • دوره: 

    38
  • شماره: 

    3
  • صفحات: 

    201-210
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    252
  • دانلود: 

    0
چکیده: 

The graphene (GR) has attracted intensive interest due to its two-dimensional and unique physical properties. In the present study, the graphene sheets were synthesized by electrochemical exfoliation of graphite in sulfuric acid solution. The polybithiophene-graphene (PbTh-GR) composite films deposited onto indium tin oxide substrate (ITO/PbTh-GR) have been prepared by the incorporation of graphene sheets into the PbTh matrix during electropolymerization under magnetic stirring from the LiClO4/CH3CN electrolyte containing the bithiophene (bTh) monomer and graphene sheets. The incorporation of graphene sheets at different masses (1, 2 and 3 mg) is ensured by the effect of the stirring of the electrolyte. The characterisation of films is effected by electrochemical methods (cyclic voltammetry and impedance spectroscopy), spectroscopic technics (FT-IR, UV-Visible), X ray diffraction, thermogravimetric analysis, and scanning electron microscopy. It was observed that the electrochemical performance measurements of the ITO/PbTh-GR (3 mg) film show a specific capacity of around 65 F/g, which is six times higher than that of ITO/PbTh films, 11 F/g.

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اطلاعات دوره: 
  • سال: 

    1395
  • دوره: 

    5
  • شماره: 

    3
  • صفحات: 

    41-50
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    1598
  • دانلود: 

    703
چکیده: 

در این تحقیق روشی جدید و آسان برای ساخت آرایه ای از نانو صفحات گرافن اکسید کاهش یافته بر روی فوم نیکل متخلخل سه بعدی ارائه گردید. یک صفحه گرافن با لبه های تیز و چین خورده بر روی فوم نیکل به روش الکتروفورتیک به دست آمد. الکترودهای ساخته شده با استفاده از میکروسکوپ الکترونی روبشی گسیل میدانی (FESEM) مشخصهیابی گردیدند. صفحات گرافنی بر روی فوم نیکل در دماهای 300،600 و 900 درجه سانتی گراد تحت گاز آرگون به مدت 4 ساعت بازپخت شدند. فعالیت الکتروشیمیایی ابرخازنی الکترودهای ساخته شده با استفاده از اندازه گیری پرشدن- تخلیه و ولتامتری چرخه ای اندازه گیری شد. برای گرافن اکسید بازپخت شده در دمای 900 درجه سانتی گراد ظرفیت ویژه بالای 148 F/g در نرخ روبشی 5 mV/s به دست آمد که از ظرفیت ویژه گرافن اکسید بازپخت شده در 600 درجه سانتی گراد (115 F/g)، گرافن اکسید بازپخت شده در 300 درجه سانتی گراد (72 F/g) و گرافن اکسید (52 F/g) بیشتر است. ابرخازن گرافن اکسید بازپخت شده در 900 درجه سانتی گراد، یک پایداری چرخه ای طولانی همراه با 96.1% ظرفیت باقی مانده پس از 200 چرخه را از خود نشان داد.

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اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    11
تعامل: 
  • بازدید: 

    131
  • دانلود: 

    0
چکیده: 

Super CAPACITORS DUE TO HIGH POWER DENSITY, ENABLING FAST CHARGING AND DISCHARGING, ARE USED TO STORE ELECTRICAL ENERGY. HOWEVER, THEIR LOWER ENERGY DENSITY IN COMPARISON WITH CONVENTIONAL BATTERIES, LIMITS THE USE OF THIS ENERGY STORAGE DEVICE. IN THIS REGARD, EXTENSIVE RESEARCHES IN THE FIELD OF SuperCAPACITORS ARE PERFORMED TO INCREASE THE CAPACITY OF Super CAPACITORS [1]. CARBON NANOTUBE (CNTS) -BASED MATERIAL ARE PROMISING MATERIALS FOR USE IN Super CAPACITOR ELECTRODES [2].DESPITE OF ADVANTAGE OF CNTS-BASED ELECTRODE, MAJOR LIMITATION OF LOW QUANTITY OF SPECIFIC CAPACITY DUE TO THEIR LOW QUANTUM capacitance REMAIN [3]. ALL DENSITY FUNCTIONAL THEORY (DFT) CALCULATIONS WERE COMPLETED USING QUANTUM ESPRESSO CODE AND PREDEW-WANG91 (GGAPW91) EXCHANGE-CORRELATION FUNCTIONAL. OUR RESULTS INDICATE THAT QUANTUM capacitance SIGNIFICANTLY IS IMPROVED BY CHANGING IN THE ELECTRONIC STRUCTURE THROUGH DOPANTS AND DEFECTS. THE OBTAINED RESULTS FROM DENSITY OF STATE (DOS) OF P-DOPED (6, 6) CNTS INDICATES THAT IMPURITY STATES ARE CREATED AROUND THE FERMI LEVEL (SEE FIGURE 1A). QUANTUM capacitance OF P-DOPED (6, 6) CNTS IN THE WATER STABILITY RANGE (FOR V=-0.4-0.83) ARE INCREASED COMPARED WITH QUANTUM capacitance OF PURE (6, 6) CNTS. IN THESE CASES THE QUANTUM capacitance IS ALMOST SYMMETRIC AROUND ZERO VOLTAGE AND INCREASED BOTH THE NEGATIVE AND THE POSITIVE BIAS (SEE FIGURE 1B).

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اطلاعات دوره: 
  • سال: 

    2012
  • دوره: 

    6
  • شماره: 

    4 (23)
  • صفحات: 

    1-7
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    332
  • دانلود: 

    0
چکیده: 

In designing a parallel resonant induction heating system, choosing a proper capacitance for the resonant circuit is quite important. The capacitance affects the resonant frequency, output power, heating efficiency and power factor. In this paper, with consideration to function of the equivalent series resistance (ESR), optimal capacitance is calculated.The induction heating resonance capacitor is achieved using Smart Bacteria Foraging Algorithm (SBFA) under voltage and frequency constraints for minimizing cost function that is including: increasing the output power and efficiency of an induction heater, while decreasing the power loss of the capacitor. The proposed algorithm mimics chemotactic behavior of E. Coli bacteria to optimize parameters. The proposed algorithm enjoys individual and social intelligence, so that it can search influx ways among hidden layers of the problem. Based on the equivalent circuit model of an induction heating system, the output power, and the capacitor losses are calculated. The effectiveness of the proposed method is verified by computer simulations, also improving the obtained results using SBFA are compared to classical bacteria foraging algorithm BFA.

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بازدید 332

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