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اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    95-111
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    215
  • دانلود: 

    27
چکیده: 

Sluggish Cognitive Tempo is used to describe a particular type of attention deficit, concentration, and slowness in information processing. The aim of this study was to investigate the psychometric properties of the Sluggish Cognitive Tempo Scale (SCTS) of the parent form among Iranian children. The present study is a descriptive study. A sample of 1700 people was selected from the provinces of Tehran, East Azerbaijan, West Azerbaijan, Kurdistan, Fars and Khorasan using cluster sampling method. 122 subjects were excluded from statistical analysis due to incomplete answers to the questionnaires and thus the final sample was reduced to 1578 parents. The confirmatory factor analysis method and internal consistency were used to compute the Sluggish Cognitive Tempo Scale factorial validity and reliability, respectively. Also, in order to examine the construct validity of the Sluggish Cognitive Tempo Scale, we computed correlations between different dimensions of Sluggish Cognitive Tempo Scale with Attention Deficit Subscale of Mental Health Assessment Questionnaire for Children and Adolescents. The results of statistical results showed that this scale has structural validity, criterion and convergence in Iranian society. The results indicate that the scale is three factors and also the validity of the scale using Cronbach's alpha method and retest test after Approved two weeks. According to the findings of the present study, the parent form of the Sluggish Cognitive Tempo Scale (SCTS) has a good validity and reliability and it can be used in research related to slow cognitive multiplication in Iranian society.

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اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    113-144
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    191
  • دانلود: 

    26
چکیده: 

One of the factors that can be the link between our intentions and actions and their external consequences is human agency, which indicates the conscious design and intentional execution of actions by the individual in order to influence future events.Objective and Method: This research with a developmental approach of psychometric method and method 1, examines the psychometric indices of the Human Factor Characteristics Scale using the classical theory of test score measurement and the graduated question-answer theory. The purpose of this study, which included high school students in Tehran, was selected by cluster sampling of 500 people as a sample size and statistical analysis was performed on 481 data. To collect the data, the ion Human Agent Characteristics Scale (2011) was used and the research questions were evaluated using IRTPRO and SPSS software.Results:The assumption of local independence based on Pearson x2 index was established by applying Simjima's calibrated question-answer theory and the assumption of being one-dimensional based on the analysis of multidimensional question-answer theory. Diagnosis parameters with question-answer approach and classical approach Test score Both item 25 approach had the lowest and item 2 had the highest diagnosis parameter. The answer thresholds for all the questions were so far apart that no option was covered by the other option, and the options were independently selected by individuals at intervals of theta. The total scale was calculated with Cronbach's alpha of 0.945, intentionality of 0.894, foresight of 0.780, self-reactivity of 0.871 and rethinking of 0.762. Also, the role of each item in internal consistency was investigated by the loop method, which all questions had a favorable role in internal consistency of this scale. The value of the validity coefficient obtained from the question-answer theory was obtained by marginal method for intentionality 0.92, forethought 0.85, self-reaction 0.91, rethinking 0.83..

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اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    55-73
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    174
  • دانلود: 

    21
چکیده: 

AbstractThe aim of this study was to investigate the validity, reliability and factor structure of the "How I Think" questionnaire to assess cognitive distortions in Iranian students. The present research design is descriptive and psychometric studies. The statistical population of this study included all male high school students in city Dezful in the academic year 1399-1400, from which 316 students were selected by multi-stage random sampling and completed the How I think and Bass and Perry Aggression Questionnaires (for Convergent validity). Factor analysis, Cronbach's alpha and Pearson correlation were used to analyze the data using SPSS and AMOS 20 software. The results of factor analysis showed that the questionnaire consists of six factors and has good fit indices. The convergent validity of this questionnaire indicated a satisfactory correlation between the dimensions of the scale "How I think" with the Aggression Questionnaire (p <0.01). Cronbach's alpha and Split- half coefficients for the whole scale and its dimensions ranged from 0.66 to 0.92.The conclusion is that the Persian version of the "How do I think" questionnaire for measuring cognitive distortions in Iranian students has acceptable psychometric properties and can be used as a valid tool in research, educational and clinical situations.

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بازدید 174

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

    1402
  • دوره: 

    53
  • شماره: 

    3
  • صفحات: 

    182-191
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    173
  • دانلود: 

    46
چکیده: 

یکی از مسائل مهم در تولید بتن، تنوع محیطی است که بر بتن و عناصر ساخته شده از این ماده تأثیر می گذارد. با توجه به اهمیت ویژگی های مختلف بتن در شرایط کوتاه مدت و بلندمدت، این مقاله با هدف بررسی تأثیر شرایط دمایی اولیه بتن خود تراکم بر ویژگی های بلندمدت آن و تعیین دمای بهینه اولیه بتن می باشد. برای این منظور، آزمایش های متعددی در سه شرایط دمایی 5، 20 و 40 درجه سانتیگراد برای ارزیابی رئولوژی و خواص مکانیکی بتن تازه در محدوده 7 و 28 روز انجام شد. در این آزمایش ها، از مخلوط های معدنی جایگزین سیمان مانند میکرو سیلیس، خاکستر بادی و زئولیت برای ساخت نمونه های بتنی استفاده شد. نتایج نشان می دهد که خواص مکانیکی نمونه ها با افزایش دمای اولیه در کوتاه مدت افزایش می یابد، در حالی که چنین خواصی در طولانی مدت در مقایسه با نمونه های ساخته شده در دمای اولیه پایین تر کاهش می یابد. علاوه بر این، سیالیت بتن خود تراکم با افزایش دمای اولیه افزایش می یابد.

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بازدید 173

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نویسندگان: 

GHAFFARI A.

اطلاعات دوره: 
  • سال: 

    2007
  • دوره: 

    33
  • شماره: 

    1
  • صفحات: 

    25-35
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    391
  • دانلود: 

    0
چکیده: 

A discrete group G is called inner amenable if there exists a mean m on l ¥ (G) such that m(xfx) = m(f) whenever fe l¥ (G), X e G and m 6 ¹ d e. The condition is considerably weaker than ordinary amenability. In this paper, among the others, we investigate the structures of inner amenable discrete groups by theoretical set theory. A sequence of characterizations of inner amenable.

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بازدید 391

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اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    11
تعامل: 
  • بازدید: 

    151
  • دانلود: 

    0
چکیده: 

IN THIS WORK, SILICA AEROGELS WERE PREPARED USING SOL-GEL POLYMERIZATION FOLLOWED BY SUPERCRITICAL DRYING METHOD. TWO STEPS ACID-BASE CATALYZED REACTION OF TETRAETHOXYSILANE (TEOS) WAS EMPLOYED. WATER AND ETHANOL WERE USED AS SOLVENT AND COSOLVENT, RESPECTIVELY. AMMONIUM HYDROXIDE AND OXALIC ACID WERE USED AS CATALYSTS. PORE SIZE DISTRIBUTION AND SPECIFIC SURFACE AREA ANALYZED USING BRUNAUER, EMMETT AND TELLER (BET) METHOD. FINALLY, THE SCANNING ELECTRON MICROSCOPY (SEM) WAS USED TO CHARACTERIZE THE MICROSTRUCTURE OF PREPARED SILICA AEROGELS. THEY ARE COMPRISED OF A FEW NANOMETER SIO2 CLUSTERS, AS COULD BE OBSERVED IN THE SEM MICROGRAPH.

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بازدید 151

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اطلاعات دوره: 
  • سال: 

    1380
  • دوره: 

    2
  • شماره: 

    5
  • صفحات: 

    311-318
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    1321
  • دانلود: 

    170
چکیده: 

در این بررسی یک توصیف نظری از خواص ساختاری استاتیکی، ارتعاشی و گذار فاز ارایه شده است. بسامدهای فونونی بلور NaCl در دمای صفر و در مسیرهای تقارنی 100]، 110 و 111 [ محاسبه شده است. محاسبات ابتدا به ساکن با استفاده از تقریبی که تلفیقی از دو روش ثابتهای نیروی بین اتمی و فونون منجمد است، انجام شده است. هم چنین ثابتهای گرانسن برای همه مدها در نقاط X و L از منطقه اول بریلوئن محاسبه شده اند. محاسبات ابتدا به ساکن براساس نظریه تابعی چگالی و شبه پتانسیل انجام گرفته است.

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بازدید 1321

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نویسندگان: 

TJONG S.C.

اطلاعات دوره: 
  • سال: 

    2006
  • دوره: 

    53
  • شماره: 

    3-4
  • صفحات: 

    73-197
تعامل: 
  • استنادات: 

    3
  • بازدید: 

    282
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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

بازدید 282

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نشریه: 

کنترل

اطلاعات دوره: 
  • سال: 

    1398
  • دوره: 

    13
  • شماره: 

    4
  • صفحات: 

    15-21
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    554
  • دانلود: 

    147
چکیده: 

کاربرد سیستم های کنترل شبکه شده که در آن ها برای انتقال سیگنال های حسگری و کنترلی از یک شبکه مشترک استفاده می شود، در حال گسترش روزافزون بوده و لذا این سیستم ها، طی دهه اخیر مورد توجه محققین قرار گرفته اند. از سوی دیگر، سیستم های نمونه برداری چند نرخی از مدت ها پیش، موضوع پژوهش های متعدد بوده اند. در این مقاله ابتدا شرایطی که تحت آن یک سیستم شبکه شده، به صورت سیستم چند نرخی قابل مدل سازی است، بیان شده و سپس با استفاده از نتایج اخیر در حوزه سیستم های شبکه شده، آخرین نتایج موجود در خصوص کنترل پذیری و پایدارپذیری سیستم های نمونه برداری چند نرخی، توسعه داده شده است. بدین منظور، شرایط کافی که کنترل پذیری (پایدارپذیری) سیستم کنترل نمونه برداری شده چند نرخی را حفظ کند، ارائه شده است. مثالی عددی جهت تبیین نتایج ارائه شده است.

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بازدید 554

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نویسندگان: 

ENTEZARI A. | ESMAILI J.

اطلاعات دوره: 
  • سال: 

    2010
  • دوره: 

    40
  • شماره: 

    2 (62)
  • صفحات: 

    1-12
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    335
  • دانلود: 

    0
چکیده: 

In this research, the properties of structural lightweight aggregate concrete (LWAC) made of local lightweight aggregates in East Azarbaijan-Iran were investigated. Considering Iran earthquake zone, the weight of structures is of high importance. Reducing the weight of building using lightweight aggregates is one of the methods to decrease the harmful effects of earthquake on structures. In this study two different types of lightweight aggregates, Scoria and Pumice, provided from Azarbaijan-Iran, were used in concrete mixes. Mechanical properties of LWAC, including compressive strength, tensile strength, modulus of rupture, modulus of elasticity and stress-strain relationship were studied. In spite of NWC, the results show that at the same conditions, strength of aggregates is the main factor controlling the compressive strength of LWAC. Twenty-seven different concrete mixes with different 28 days compressive strengths varying from 24 to 51 Mpa were used in this study to measure the compressive strength, tensile strength, modulus of rupture, modulus of elasticity and strain at maximum stress which were compared with those of NWC. It was found that for the same compressive strength (24-51 Mpa) the modulus of elasticity of LWAC (10.92-18.77 Gpa) was less than that of NWC (17.53-28.31 Gpa) and tensile strength and modulus of rupture of LWAC was also less than NWC. The corresponding strain of the maximum stress in LWAC was found to be in the range of 2.55-3.78 mm/m, whereas for the same compressive strength, it was at range of 2.28-3.41 mm/m in NWC, this imply to lower modules of elasticity in LWAC compared with NWC.

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