Theoretical formula for the cosmic-ray muon attenuation coefficients of Pb, Cu, Zn, and Al
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Publication Date
Tue Jan 01 2019
Journal Name
Aip Conference Proceedings
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Publication Date
Sat Sep 01 2018
Journal Name
Polyhedron
Novel dichloro (bis {2-[1-(4-methylphenyl)-1H-1, 2, 3-triazol-4-yl-κN3] pyridine-κN}) metal (II) coordination compounds of seven transition metals (Mn, Fe, Co, Ni, Cu, Zn and Cd)
The 1
3-dipolar cycloaddition “click” reaction between an azide and an alkyne to give a 1
2
3-triazole was reported by Huisgen in 1961 [1]. In 2002 the Copper(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) to prepare a 1
2
3-triazole was reported [2]
[3]. The existence of relatively basic nitrogen atoms in the 1
2
3-triazole rings
and the possibility of introducing additional donor groups in the substituents (Fig. 1)
made the CuAAC “click” reaction an attractive method to prepare differently substituted 1
2
3-triazoles. These compounds have been used as ligands to coordinate to various metal ions that display a range of applications such as in electrochemical and photochemical studies
in supramolecular chemistry
magnetism
metal-ion sensing and catalysis [4]. The reasons for the success of the “click” reaction
is that it is easy to carry out and is widely applicable. It is not affected by a variety of functional groups
and can be carried out with a variety of Cu(I) catalysts and solvents
including aqueous conditions. The Cu(I) catalysts overcome the high activation energy barrier of the non-catalyzed Huisgen reaction by changing the mechanism of the reaction. A large variety of copper catalysts can be used for the CuAAC reaction
on condition that the maximum concentration of Cu(I) species is generated during the reaction. The pre-catalyst can be a Cu(II) salt (usually CuSO4) together with a reducing agent (often sodium ascorbate) or a Cu(I) compound in the presence of a base or amine ligand and a reducing agent to prevent oxidation to Cu(II). Some strong oxidising cupric salts or complexes such as Cu(OAc)2 also work. The solvent is very flexible from organic to aqueous
with the most commonly used combination water + an alcohol (t-BuOH
MeOH or EtOH). The key role of the solvent or solvent mixture is to solubilize the substrates and Cu(I) catalyst in order to ensure rapid reactions. Such aqueous conditions are very useful for biochemical conjugations
as well as for organic syntheses.
We recently reported on the synthesis of a series of differently substituted 1
2
3-triazole chromophores
the substituted 2-(1-phenyl-1H-1
2
3-triazol-4-yl)pyridine ligands [5]
see Fig. 2 middle
with substituents R = H (L1)
CH3 (L2)
OCH3 (L3)
COOH
F
Cl
CN
CF3
O(CH2)3CH3 and N(CH3)2. These versatile ligands were found to coordinate to various first row transition metals
such as manganese
cobalt and nickel [6]. Here we extend the series to include more first row transition metal(II) coordination compounds
iron
copper and zinc
as well as a second row transition metal(II) coordination compound
cadmium
containing the 2-(1-(4-methyl-phenyl)-1H-1
2
3-triazol-1-yl)pyridine chromophore (Fig. 2 right with R = CH3). This series of seven novel coordination compounds is the first series of pyridyl-triazole based transition metal coordination compounds where seven different transition metals are coordinated to the same 1
2
3-triazole chromophore
namely 2-(1-(4-methyl-phenyl)-1H-1
2
3-triazol-1-yl)pyridine.
Publication Date
Mon May 11 2020
Journal Name
Baghdad Science Journal
Oscillation Criteria for Solutions of Neutral Differential Equations of Impulses Effect with Positive and Negative Coefficients: eventually positive solutions and differential inequalities
Impulsive Neutral Differential Equations
Oscillation
Variable Delays
Variable Coefficients
In this paper, some necessary and sufficient conditions are obtained to ensure the oscillatory of all solutions of the first order impulsive neutral differential equations. Also, some results in the references have been improved and generalized. New lemmas are established to demonstrate the oscillation property. Special impulsive conditions associated with neutral differential equation are submitted. Some examples are given to illustrate the obtained results.
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Publication Date
Sat Dec 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
Application of “LIML_LVR” method practically according to the general formula K-CLASS on suggestion simultaneous equation
تطبيق طريقة
: Application of “LIML_LVR”
في هذا البحث نحاول تسليط الضوء على إحدى طرائق تقدير المعلمات الهيكلية لنماذج المعادلات الآنية الخطية والتي تزودنا بتقديرات متسقة تختلف أحيانا عن تلك التي نحصل عليها من أساليب الطرائق التقليدية الأخرى وفق الصيغة العامة لمقدرات K-CLASS. وهذه الطريقة تعرف بطريقة الإمكان الأعظم محدودة المعلومات "LIML" أو طريقة نسبة التباين الصغرى"LVR
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Publication Date
Thu Sep 13 2018
Journal Name
Baghdad Science Journal
Gamma Ray Effect on the Properties of Coumarin C47 Laser Dye
Absorption
Chloroform
Concentration
Spectrum
Source
The research is concerned about studying the absorption spectrum of the solution coumarin dye C47. The chloroform solvent was used with C47 dye in three different concentrations 10-4, 10-5 and 10-6 M. The laser dye solution was prepared by dissolving the required amount of dye in chloroform alcohol, while studying absorption spectrum before and after irradiation with gamma ray by cobalt-60 source 60Co at exposure time, which are 0, 4, 6 and 18 hours with different absorbed doses 0, 136, 204 and 612 Gy. The results show that red shift in the absorption spectrum was increased by increasing the concentration of laser dye solutions , while the increase of gamma dose led to increase the red shift after irradiation, as the exposure period and irr
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Publication Date
Fri Feb 28 2020
Journal Name
Neuroquantology
Publication Date
Tue May 01 2012
Journal Name
Journal Of Engineering
Study on wind loads coefficients and flow field characteristics around the parabolic trough with stiffeners
wind load coefficient
Publication Date
Tue May 01 2018
Journal Name
Journal Of Engineering
Evaluation of Job-Mix Formula Tolerances as Related to Asphalt Mixtures Properties
Asphalt
Job-Mix
tolerance
Marshall test
compressive test.
The current Iraqi standard specifications for roads and bridges allowed the prepared Job-Mix Formula for asphalt mixtures to witness some tolerances with regard to the following: coarse aggregate gradation by ± 6.0 %, fine aggregate gradation by ± 4.0 %, filler gradation by ± 2.0 %, asphalt cement content by ± 0.3 % and mixing temperature by ± 15 oC. The objective of this work is to evaluate the behavior of asphalt mixtures prepared by different aggregates gradations (12.5 mm nominal maximum size) that fabricated by several asphalt contents (40-50 grade) and various mixing temperature. All the tolerances specified in the specifications are taken into account, furthermore, the zones beyond these tolerances
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Publication Date
Thu Jan 15 2015
Journal Name
مجلة كلية التربية-المؤتمر العلمي التخصصي لكلية التربية
Investigation the Effect of Irradiation by Gamma-Ray on the Structural
and Optical Properties of (CIGS) Films
CIGS
Structural properties
Optical Properties
gamma irradiation
Publication Date
Sat Jan 01 2022
Journal Name
3rd International Scientific Conference Of Alkafeel University (iscku 2021)
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