فیلترها/جستجو در نتایج    

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نویسندگان: 

LAPTHORN A.J. | HARRIS D.C.

نشریه: 

NATURE

اطلاعات دوره: 
  • سال: 

    1994
  • دوره: 

    369
  • شماره: 

    -
  • صفحات: 

    455-461
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    187
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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

بازدید 187

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نویسنده: 

KIA REZA

اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    17
تعامل: 
  • بازدید: 

    242
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

A REAL PERFECT PERIODIC Crystal IS A SOLID OBJECT IN WHICH A SPECIAL PATTERN IS REPEATED OVER AND OVER IN THREE- DIMENSION. THE Crystal structure DETERMINED FROM THE DIFFRACTION DATA IS THE SPATIAL AVERAGEOVER THE WHOLE Crystal WHICH DOESN’T GIVE REAL IMAGE OF THE CHANGES IN THE SOLID STATE BY THE CONVENTIONAL ROUTINE structure DETERMINATION METHOD...

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بازدید 242

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اطلاعات دوره: 
  • سال: 

    2016
  • دوره: 

    23
تعامل: 
  • بازدید: 

    219
  • دانلود: 

    0
چکیده: 

A NEW COMPLEX OF FORMULA [NI (HPHPYF) CL2] (HPHPYF=PHENYLPYRIDYLFORMAMIDINE) HAS BEEN SYNTHESIZED AND THE Crystal structure DETERMINED BY X-RAY DIFFRACTION METHODS. THE COMPLEX CrystalLIZES IN THE MONOCLINIC SPACE GROUP P21/C WITH A=13.304 (2) A, B=12.789 (2) A, C=7.767 (13) A, A=90 (5) °, B=94.101 (3) O, V=1378.6 (4) A3, AND Z=4. THE structure OF THIS COMPLEX IS MONONUCLEAR WITH THE NICKEL (II) ION TETRAHEDRALLY COORDINATED AND BOUND TO THE HPHPYF THROUGH THE NITROGEN ATOMS. THE NI-N BOND LENGTHS ARE IN THE RANGE OF 1.96-1.98 (4) A.

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بازدید 219

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نویسنده: 

MANSOURI GHOBAD | Mavali Vahid

اطلاعات دوره: 
  • سال: 

    2016
  • دوره: 

    23
تعامل: 
  • بازدید: 

    203
  • دانلود: 

    0
چکیده: 

THE Crystal structure OF DICHOLRO (PHENYLPYRIDYLFORMAMIDINE) ZINC (II), [ZN (HPHPYF) CL2], HAS BEEN DETERMINED BY SINGLE-Crystal X-RAY DIFFRACTION METHOD. THIS COMPLEX HAS A ORTHORHOMBIC Crystal SYSTEM (Z=4) AND SPACE GROUP OF P 21/C WITH A=13.434 (2) A, B=12.787 (2) A, C=7.913 (13) A, B=90.101 (3) O, AND V=1354.07 (4) A3. ORTEP OF THE COMPLEX SHOWS THAT THE GEOMETRY ABOUT THE ZN (II) IS DISTORTED TETRAHEDRAL. THE ZN-N BOND LENGTHS ARE IN THE RANGE OF 1.97 (4) -2.01 (4) A AND, COMPARABLE TO THOSE FOUND FOR THE structureS OF (CARBONATO) POLYPYRIDYL CO (III) COMPLEXES.

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بازدید 203

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اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    20
تعامل: 
  • بازدید: 

    140
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

SINCE THE DISCOVERY OF WACKER OXIDATIONS, THIS PD CATALYST SYSTEM HAS BEEN EXTENDED TO THE OXIDATION OF DIVERSE TERMINAL OLEFINS, WHICH OFFERS A POWERFUL METHOD FOR THE SYNTHESIS OF METHYL KETONES [1-2]. HOWEVER, THE SELECTIVE SYNTHESIS OF CARBONYL COMPOUNDS FROM INTERNAL OLEFINS USING WACKER METHOD REMAINS A MAJOR CHALLENGE...

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بازدید 140

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نشریه: 

BIOCHEMISTRY

اطلاعات دوره: 
  • سال: 

    1992
  • دوره: 

    31
  • شماره: 

    22
  • صفحات: 

    5172-5176
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    74
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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بازدید 74

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نویسندگان: 

اطلاعات دوره: 
  • سال: 

    2021
  • دوره: 

    166
  • شماره: 

    -
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    35
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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

بازدید 35

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اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    7-32
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    186
  • دانلود: 

    39
چکیده: 

Nowadays, the fundamental role of having a purpose for life in physical and mental health has been confirmed. According to victor frankl, presence of a purpose in life gives life a meaning and increases resilience against pains and traumas. The importance of the purpose in life construct reveals the need for a reliable and valid tool to measure it. Crumbaugh and Maholick's purpose in life questionnaire is the first and one of the most applied tools for the assessment of life's purposefulness. The aim of this research is to determine the factor structure of purpose in life questionnaire. The questionnaire was administered on 206 students who were selected through random stratified sampling at Ferdowsi University of Mashhad. Exploratory factor analysis showed that there are two factors "comprehension" and "purpose" and this finding were confirmed by confirmatory factor analysis. Altogether results of this research showed factor validity of the purpose in life questionnaire with a two factor pattern

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بازدید 186

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نویسندگان: 

HAKIMYFARD ALIREZA

اطلاعات دوره: 
  • سال: 

    2018
  • دوره: 

    9
  • شماره: 

    2
  • صفحات: 

    170-178
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    226
  • دانلود: 

    0
چکیده: 

Nanostructured Ni2As2O7 semiconductor samples were synthesized by a solid state method among As2O3 and Ni(NO3)2.6H2O raw materials at 650oC (S1) and 750oC (S2) as reaction temperatures. The synthesized nanomaterials were characterized by powder X-ray Diffraction (PXRD) technique and Fourier-Transform Infrared (FTIR) spectroscopy. The Rietveld analysis showed that the obtained materials were Crystallized well in the triclinic Crystal structure with the space group P1. The data of Rietveld analysis showed that the purity of the synthesized nanomaterials was increased by increasing the reaction temperature. The morphologies of the synthesized materials were studied by field emission scanning electron microscope (FESEM). It was found that the morphology of the obtained materials was changed from homogeneous sponge to particles and somewhat porous structure, by increasing the reaction temperature. Besides, the average particle sizes were increased considerably by increasing the reaction temperature. Ultraviolet-visible spectra analysis showed that the synthesized Ni2As2O7 nanomaterials had strong light absorption in the ultraviolet light region. The direct optical band gap energies were 3.20, 3.90, 4.80 eV and 2.9, 3.40, 4.70 eV for S1 and S2, respectively. The data showed that the band gaps were decreased by increasing the reaction temperature that can be due to the increasing the Crystallite sizes of the targets.

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بازدید 226

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نویسندگان: 

Azizi Mahdi | Baghalzadeh Shishehgarkhaneh Milad | Basiri Mahla

اطلاعات دوره: 
  • سال: 

    2022
  • دوره: 

    6
  • شماره: 

    2
  • صفحات: 

    205-220
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    14
  • دانلود: 

    0
چکیده: 

Optimization is an act of decision-making to reach a point in which the overall behavior of the considered system is acceptable by the field's experts. In recent decades, construction companies have been willing to provide housing services with lower construction costs that people of different kinds can afford. Although academics have introduced form-dominant methods, using artificial intelligence (AI) in structural design has been one of the most critical challenges in recent years. In the current study, the applicability of the Crystal structure Algorithm (Crystal) as one of the recently developed metaheuristic algorithms is investigated in the optimum design of truss structures, in which the basic concepts of Crystals, including the lattice and basis, are in perspective. For numerical purposes, the 10-bar, 72-bar, and 200-bar truss structures are considered as design examples. Furthermore, for constraint-handling purposes, a simple penalty approach is implemented in Crystal. A complete statistical analysis is conducted through multiple optimization runs for comparative purposes; at the same time, other metaheuristic approaches have been derived from the literature. Based on the results of the Crystal and other methods in dealing with truss optimization problems, the utilized method can provide better and more competitive results in most cases.

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بازدید 14

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