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متن کامل


نویسندگان: 

GRIEPENTROG H. | TSATSARONIS G. | MOROSUK T.

اطلاعات دوره: 
  • سال: 

    2008
  • دوره: 

    -
  • شماره: 

    -
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    151
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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بازدید 151

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نویسندگان: 

وودفرد کیت

اطلاعات دوره: 
  • سال: 

    1388
  • دوره: 

    20
  • شماره: 

    202-203
  • صفحات: 

    99-113
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    998
  • دانلود: 

    293
کلیدواژه: 
چکیده: 

برای درک بهتر مفهوم تعاونیهای «نسل جدید» بهتر است ابتدا نگاهی به تعاونیهای «سنتی» بیندازیم، به این دلیل که تعاونیهای نسل جدید در پاسخ به محدودیتهای ناشی از تعاونیهای سنتی به وجود آمده اند.....

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بازدید 998

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اطلاعات دوره: 
  • سال: 

    1394
  • دوره: 

    13
تعامل: 
  • بازدید: 

    434
  • دانلود: 

    197
چکیده: 

لطفا برای مشاهده چکیده به متن کامل (PDF) مراجعه فرمایید.

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

MORADI M. | PISHVAIE M.R.

اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    8
تعامل: 
  • بازدید: 

    145
  • دانلود: 

    0
چکیده: 

THE PRESENT PAPER FOCUSES ON THE SUPERSTRUCTURE OPTIMIZATION OF THE METHANOL AND ELECTRICITY CO-GENERATION ENERGY SYSTEM. A GENERAL SUPERSTRUCTURE WHICH CONSISTS OF ALL THE AVAILABLE TECHNOLOGIES IS CONSIDERED FOR THE PROPOSED ENERGY SYSTEM. EACH TECHNOLOGY FOR EACH PART IS SIMULATED BY THE COMMERCIAL SIMULATOR ASPEN PLUSTM. FOR OBTAINING THE BEST PROCESS DESIGN IN ORDER TO MAXIMUM PROFIT, THE SUPERSTRUCURE IS FORMULATED AS A MIXED INTEGER NONLINEAR PROGRAMMING (MINLP) OPTIMIZATION PROBLEM. THE OPTIMIZER BASED ON GENETIC ALGORITHM THAT IS CODED WITH MATLAB IS COUPLED TO THE PROCESS SIMULATOR BY COMPONENT OBJECT MODEL (COM) TECHNOLOGY FOR SOLVING THE OBTAINED OPTIMIZATION PROBLEM. THE SOLUTION APPROACH FOR THE SUPERSTRUCTURE OPTIMIZATION IS DISCUSSED AND RESULTS ARE PRESENTED.

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نویسندگان: 

اطلاعات دوره: 
  • سال: 

    2012
  • دوره: 

    14
  • شماره: 

    12
  • صفحات: 

    811-815
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    77
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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بازدید 77

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اطلاعات دوره: 
  • سال: 

    2019
  • دوره: 

    7
  • شماره: 

    4
  • صفحات: 

    57-66
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    100
  • دانلود: 

    0
چکیده: 

Among nanostructured materials, magnetic nanowires have been heeded because of their high shape anisotropy and their easy fabrication methods. Electrochemical deposition on the anodic aluminium oxide (AAO) is one of the best methods to grow different nanowires. In this paper, the AAO was fabricated on the 1100 Al alloy substrate by hard anodizing in 0. 3 M oxalic acid solution. Then, a barrier layer thinning process was carried out for the electrodeposition process. A pulsed electrodeposition process was used to fill the nano-pores. According to this method, cobalt nanowires were grown in the nano-holes. Structural, crystalline, and magnetic properties of the samples were evaluated using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM), respectively. The results showed that nanowires have a diameter of 87 nm and crystalline structure with crystalline plates in directions (100), (002), and (110). A coercivity value of 600 Oe was obtained for nanowires, which is several times larger than cobalt bulk.

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

    2014
  • دوره: 

    17
تعامل: 
  • بازدید: 

    211
  • دانلود: 

    0
چکیده: 

BACKGROUND: THE BURNING OF HYDROCARBONS FOR ENERGY CAUSES SEVERE AIR POLLUTION AND CLIMATE CHANGE. THEREFORE, ALTERNATIVE CLEAN ENERGY TECHNOLOGIES ARE BEING WIDELY EXPLORED. THE BURNING OF HYDROGEN GAS IS ENVIRONMENTALLY FRIENDLY BECAUSE THE ONLY PRODUCT OF THE REACTION IS WATER [1]. ONE OF THE HYDROGEN GENERATION METHODS IS CATALYTIC HYDROLYSIS OF NABH4 SOLUTION. METALLIC NANOPARTICLES BECAUSE OF SMALL SIZE AND HIGH SURFACE AREA ARE SUITABLE CATALYSTS FOR THIS PROCESS. IN PARTICULAR, THE SUPPORTED TRANSITION METALS CATALYSTS ARE HIGHLY APPRECIATED IN THE PRACTICAL APPLICATION OWING TO THE REUSABILITY, READY CONTROLLABILITY OF THE HYDROLYSIS REACTION AND EASY SEPARATION FROM THE FUEL SOLUTION [2].METHODS: CO-B/FE3O4 NANOPARTICLES WERE SYNTHESIS UNDER ARGON ATMOSPHERE. FIRST, A SUITABLE AMOUNT OF FE3O4 SUPPORT WAS DISPERSED IN CO (II) SOLUTION UNDER ULTRASONIC CONDITION. THEN NABH4 SOLUTION WAS ADDED SLOWLY INTO SOLUTION. THE BLACK PRECIPITATES WAS SEPARATED FROM THE SOLUTION BY AN EXTERNAL MAGNETIC FIELD, WASHED WITH DEIONIZED WATER AND DRIED IN AN OVEN AT 40OC.RESULTS: SURFACE MORPHOLOGY AND PHASE OF THE SYNTHESIZED NANOPARTICLES WERE EXAMINED BY SEM AND XRD, RESPECTIVELY. SEM IMAGES SHOWED THE AVERAGE PARTICLE SIZE OF THE CATALYST WAS ABOUT 70 NM AND XRD PATTERN INDICATES THAT BOTH CO-B AND FE3O4 EXIST IN THE PREPARED CATALYST. THE CATALYTIC ACTIVITY OF THE CATALYST FOR HYDROLYSIS OF NABH4 SOLUTION WAS EVALUATED. THE ACTIVATION ENERGY OF THIS PROCESS IS CALCULATED TO BE 57 KJ MOL-1. HYDROGEN GENERATION RATE INCREASED AS THE NABH4 CONCENTRATION AND TEMPERATURE WERE INCREASED. THE STRUCTURE EFFECT OF FE3O4 HELPED THE CO-B NANOCLUSTERS TO HAVE HIGH DISPERSION AND BETTER THERMAL STABILITY, RESULTING IN HIGH ACTIVITY ON HYDROLYSIS OF NABH4 SOLUTION.CONCLUSION: CO-B/FE3O4 CATALYST EXHIBITED HIGH CATALYTIC ACTIVITY FOR THE HYDROLYSIS OF AQUEOUS NABH4 SOLUTION, RESULTING IN HIGH RATE OF HYDROGEN GENERATION AND LOW ACTIVATION ENERGY. CATALYSTS CAN BE CONVENIENTLY SEPARATED FROM THE REACTION SOLUTION, REPEATEDLY USED AND SHOWING CONSIDERABLE RECYCLING PERFORMANCE.

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اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    16
  • شماره: 

    59
  • صفحات: 

    137-166
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    225
  • دانلود: 

    76
چکیده: 

هم آفرینی ارزش، موضوعی است که توجه بسیاری از نهادها و سازمان­ها و به خصوص دانشگاه­ها را به خود جلب نموده است و ارائه الگویی جامع، فراگیر و کاربردی به ویژه در آموزش عالی می تواند بسیار راهگشا باشد. بدین لحاظ هدف این تحقیق نخست شناسایی عوامل، مولفه ها و پیامدهای هم آفرینی ارزش دانشگاهی با تاکید بر دانشگاه­های نسل چهارم و پنجم و طراحی الگوی مفهومی مربوطه، و سپس ارائه و بررسی الگوی جامع و بومی هم آفرینی ارزش دانشگاهی در آموزش عالی ایران می باشد. پژوهش حاضر از لحاظ نحوه گردآوری داده­ها، با رویکرد آمیخته اکتشافی می باشد. در بخش کیفی تحقیق جهت شناسایی عوامل، مولفه­ها و پیامدهای هم آفرینی ارزش از روش متاسنتز و جهت پالایش این موارد و طراحی الگوی مفهومی از روش دلفی فازی و نظرات 20 نفر از خبرگان استفاده شد. در بخش کمی، جامعه آماری کلیه اساتید دانشگاه­های دولتی استان کرمان به تعداد 1250 نفر هستند، که بر اساس جدول مورگان تعداد 295 نفر به عنوان نمونه تعیین گردید. الگوی تحلیلی با استفاده از داده­های جمع­آوری شده در این بخش پس از تحلیل عاملی انجام گرفته با با تکنیک مدلسازی معادلات ساختاری و با نرم­افزار Smart PLS 3 بررسی گردید. نهایتا مدل استراتژیک هم­آفرینی ارزش دانشگاهی با 16 عامل، 23 مولفه و 13 پیامد و هر کدام در سه دسته طراحی و آزمون شد و به عنوان مدلی پیشنهادی جهت هم­آفرینی ارزش دانشگاهی ارائه شد. برازش مدل نهایی نشان از وضعیت بسیار مناسب مدل تحقیق دارد.

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اطلاعات دوره: 
  • سال: 

    2009
  • دوره: 

    7
  • شماره: 

    SUPPL 2
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    219
  • دانلود: 

    0
چکیده: 

Introduction: Understanding neuroectoderm formation and its subsequent diversification to functional neural subtypes remains elusive. We have shown here for the first time that embryonic stem cells (ESCs) can differentiate into neurons and motor neurons (MNs) by using a co-culture embryonic notochord model in vitro.Materials and Methods: Mouse ESCs were induced to form neural precursors via timed exposure to retinoic acid (RA) using the 4-/4+ RA protocol. These cells were then co-cultured with alginate bead-encapsulated notochords isolated from Hamburger and Hamilton stage 6-10 chick embryos. The use of notochord alone was not able to induce neural differentiation from ESCs and therefore, notochord does not possess neural inducing activity.Results: The most successful neuronal cells and MN differentiation was only observed following the co-culture of RA-pretreated ESCs with notochord. This resulted in a significantly greater number of cells expressing microtubule associated protein 2 (MAP2), HB9, choline acetyltransferase (ChAT) and MN-specific genes.Conclusion: While further characterization of these differentiated cells will be essential before transplantation studies commence, these data illustrate the effectiveness of embryonic notochord co-culture, in providing valuable molecular cues for directed differentiation of ESCs towards an MN lineage.

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اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    16
  • شماره: 

    6
  • صفحات: 

    779-783
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    408
  • دانلود: 

    0
چکیده: 

Objective(s): Sertoli cells support in vivo germ cell production; but, its exact mechanism has not been well understood. The present study was designed to analyze the effect of Sertoli cells in differentiation of mouse embryonic stem cells (mESCs) to germ cells.Materials and Methods: A fusion construct composed of a Stra8 gene promoter and the coding region of enhanced green fluorescence protein was produced to select differentiated mESCs. To analyze sertoli cells’ effect in differentiation process, mESCs were separated into two groups: the first group was cultured on gelatin with retinoic acid treatment and the second group was co-cultured with sertoli cell feeder without retinoic acid induction. Expressions of pre-meiotic (Stra8), meiotic (Dazl and Sycp3) and post-meiotic (Prm1) genes were evaluated at different differentiation stages (+7, +12 and +18 days of culture).Results: In the first group, expressions of meiotic and post-meiotic genes started 12 and 18 days after induction with retinoic acid, respectively. In the second group, 7 days after co-culturing with Sertoli cells, expression of meiotic and post-meiotic genes was observed.Conclusion: These results show that differentiation process to germ cells is supported by Sertoli cells. Our findings provide a novel effective approach for generation of germ cell in vitro and studying the interaction of germ cells with their niche.

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بازدید 408

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