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Search Results: 1 - 10 of 4768 matches for " <sup>54</sup>Fe "
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Quantum Isomorphic Shell Model: Multi-Harmonic Shell Clustering of Nuclei  [PDF]
G. S. Anagnostatos
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.45B011
Abstract: The present multi-harmonic shell clustering of a nucleus is a direct consequence of the fermionic nature of nucleons and their average sizes. The most probable form and the average size for each proton or neutron shell are here presented by a specific equilibrium polyhedron of definite size. All such polyhedral shells are closely packed leading to a shell clustering of a nucleus. A harmonic oscillator potential is employed for each shell. All magic and semi-magic numbers, g.s. single particle and total binding energies, proton, neutron and mass radii of 40Ca, 48Ca, 54Fe, 90Zr, 108Sn, 114Te, 142Nd, and 208Pb are very successfully predicted.

 

Investigation of the Appropriate Partial Level Density Formula for Pre-Equilibrium Nuclear Exciton Model  [PDF]
Shafik Shakir Shafik, Ali Dawoud Salloum
Journal of Applied Mathematics and Physics (JAMP) , 2013, DOI: 10.4236/jamp.2013.13008
Abstract:

Ericson formula represents the first formula, which was suggested to describe the partial level density (PLD) formula in pre-equilibrium region of the nuclear reactions. Then a number of corrections were added to this formula in order to make it more suitable to physical meaning. In this paper, there are two aims to be done: the first aim is to study the correspondence between one and two-components formulae in Ericson, Pauli, and pairing corrections; the second aim is to compare and study the results of Comprehensive formula, which contents with all corrections, with Ericson, Pauli, and pairing formulae. The Comprehensive formula was suggested to simulate the reality. To achieve these aims the 56Fe and 90Zr nuclei were chosen and the results showed that the difference between one and two-components formulae was too small which can be neglected. Furthermore, the results strongly recommended that for cross section calculations of the nuclear reaction, one must use Comprehensive formula rather than Pauli formula.

酸性溶液中Fe2+ /Fe3+相互转换对电极还原行为的影响
Effect of?Fe2+/Fe3+Interconvertion on Reduction Behavior of Fe3+ in Acidic Electrolytes

秦建新,林 峰,刘文平,陈 超,任孟德
QIN Jian-xin
, LIN Feng, LIU Wen-ping, CHEN Chao, REN Meng-de

- , 2017, DOI: 10.13208/j.electrochem.161129
Abstract: 摘要 采用线性扫描伏安法和循环伏安法研究了含有Cl-、SO42-的酸性溶液中Fe2+/Fe3+相互转换对电极反应和Fe3+还原过程的影响. 结果表明: [Fe]T=1 mol·L-1条件下,溶液中Fe3+/Fe2+的还原析出过程经过两个阶段:(1) E=0.35 V左右Fe3+还原成Fe2+过程; (2) E=-0.3 V之后H+的还原同时Fe2+离子与OH-相结合生产Fe(OH)2; Fe3+/Fe2+的相互转化主要影响Fe3+的第一还原阶段的还原峰电流和峰电位. |ipa/ipc|值随c(Fe3+ )/c(Fe2+ )增大而增大,且扫描速度慢时影响大,扫描速度快时影响小; 0.50 mol·L-1 Fe2++0.50 mol·L-1 Fe3+时,随扫描速率的变化|ipa/ipc|值变化最小(|ipa/ipc|≈1.20). 同时,c(Fe3+ )/c(Fe2+ )也影响平衡电位,平衡电位随c(Fe3+ )/c(Fe2+ )增大而正移,电位从E1=0.501 V升至E5=0.565 V
X-Ray Diffraction, Electron Paramagnetic Resonance and Optical Absorption Study of Bauxite  [PDF]
Tanguturi Ravindra Reddy, Krishnan Thyagarajan, Ovidio Almanza Montero, Sanapa Reddy Lakshmi Reddy, Tamio Endo
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2014, DOI: 10.4236/jmmce.2014.22015
Abstract: The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be gibbsite in phase. The transitional metal ions present were investigated using electron paramagnetic resonance (EPR) and optical absorption spectra. The EPR results suggest that Fe3+ has replaced Al3+ in the unit cell of bauxite. The optical absorption spectrum is due to Fe3+ which indicates that it is in distorted octahedral environment. The near-infrared (NIR) spectrum is due to water fundamentals and combination overtones, which confirm the formula of the compound. The impurities in the mineral are identified using spectroscopic techniques.
Nonlinear Change in Refractive Index and Transmission Coefficient of ZnSe:Fe2+ at Long-Pulse 2.94-μm Excitation  [PDF]
Alexander V. Kir’yanov, Nikolai N. Il’ichev, Elmira S. Gulyamova, Alexander S. Nasibov, Peter V. Shapkin
Optics and Photonics Journal (OPJ) , 2015, DOI: 10.4236/opj.2015.51003
Abstract: An experimental study of the nonlinear changes in refractive index and transmission coefficient of single-crystal ZnSe:Fe2+, fabricated through the Fe-diffusion method, at long-pulse (~300 ns), sub-mJ, 2.94-mm Z-scan probing is reported. As well, a theoretical model based on the generalized Avizonis-Grotbeck equations is developed and applied for straightforward fitting of the open- and closed-aperture Z-scans, obtained for ZnSe:Fe2+ with different Fe2+ centers concentrations. The modeling results reveal that the contributions in the absorption and refractive index nonlinearities of ZnSe:Fe2+ are “common” resonant-absorption saturation (the minor part) and pulse-induced heating of the samples (the major part), which are strongly dependent on Fe2+ concentrations. Large values of the index change (>~10-3) and partial resonant-absorption bleaching (limited by ~50%), both produced via the thermal effect mainly, are the features of the ZnSe:Fe2+ samples inherent to this type of excitation.
Radiolanthanides Device Production  [PDF]
F. Monroy-Guzman, F. Jimenez Barreiro, E. Jaime Salinas, A. L. Vera Trevi?o
World Journal of Nuclear Science and Technology (WJNST) , 2015, DOI: 10.4236/wjnst.2015.52011
Abstract: 149Pm, 166Ho, 161Tb and 177Lu conjugated to chemical agents (monoclonal antibodies, polypeptide, etc.) have the appropriate decay characteristics for imaging and therapeutic studies and consequently the potential to be useful in radiotherapy and diagnosis. These carrier-free radioisotopes can be produced by neutron irradiation of a lanthanide target followed by β-?decay, and a posterior radiochemical separation of the daughter radionuclide from macro-amounts of the parent target. In order to produce carrier free 149Pm, 161Tb, 166Ho and 177Lu for radiotherapy, with a radionuclide purity of more than 99.9%, a device production was developed based on separation of Nd/Pm, Gb/Tb, Dy/Ho and Yb/Lu by extraction chromatography.
Effect of Dietary Nitrate on Force Production and Sarcoplasmic Reticulum Ca2+ Handling in Rat Fast-Twitch Muscles Following Eccentric Contraction  [PDF]
Satoshi Matsunaga, Chihiro Aibara, Daiki Watanabe, Keita Kanzaki, Yurie Morizaki, Sumiko Matsunaga-Futatsuki, Masanobu Wada
Open Journal of Applied Sciences (OJAppS) , 2018, DOI: 10.4236/ojapps.2018.812049
Abstract: Impaired excitation-contraction coupling occurs in eccentric contraction (ECC)-induced damaged muscles. It has been suggested that sarcoplasmic reticulum (SR) is susceptible to damage in the overstretched regions possibly marking the basis of excitation-contraction coupling damage. Recent studies have shown that dietary nitrate supplementation enhances SR function in fast-twitch muscles. In this study, we aimed to investigate whether dietary nitrate supplementation can alleviate a decline in muscle contractile properties and SR function following ECC. To this end, force production, Ca2+ uptake, Ca2+ release, and Ca2+-ATPase activity of the SR were examined in rat fast-twitch muscles immediately following ECC for 200 repetitions. In comparison with contralateral resting muscles, nitrate supplementation for up to 3 days resulted in an obvious decline in force production. However, there were no differences in terms of force production between 6-day nitrate-treated and contralateral muscles. Similar to the observations regarding force production, the SR Ca2+ release rate changed from an obvious decrease following the 0- and 3-day dietary nitrate supplementation to no difference following the 6-day nitrate supplementation. In contrast, ECC decreased the Ca2+-ATPase activity and Ca2+ uptake rate, irrespective of the period of dietary nitrate supplementation. Overall, these results indicate that dietary nitrate supplementation can alleviate ECC-related decreases in force production mediated through inhibited reductions in the SR Ca2+ release function.
Intel® Math Kernel Library PARDISO* for Intel® Xeon PhiTM Manycore Coprocessor  [PDF]
Alexander Kalinkin, Anton Anders, Roman Anders
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.68121
Abstract: The paper describes an efficient direct method to solve an equation Ax = b, where A is a sparse matrix, on the Intel® Xeon PhiTM coprocessor. The main challenge for such a system is how to engage all available threads (about 240) and how to reduce OpenMP* synchronization overhead, which is very expensive for hundreds of threads. The method consists of decomposing A into a product of lower-triangular, diagonal, and upper triangular matrices followed by solves of the resulting three subsystems. The main idea is based on the hybrid parallel algorithm used in the Intel® Math Kernel Library Parallel Direct Sparse Solver for Clusters [1]. Our implementation exploits a static scheduling algorithm during the factorization step to reduce OpenMP synchronization overhead. To effectively engage all available threads, a three-level approach of parallelization is used. Furthermore, we demonstrate that our implementation can perform up to 100 times better on factorization step and up to 65 times better in terms of overall performance on the 240 threads of the Intel® Xeon PhiTM coprocessor.
Tb3+/Eu3+共掺杂的CaMoO4荧光粉在防伪技术领域的应用
The Application of Tb3+/Eu3+ Codoped CaMoO4 Phosphors in the Field of Anti-Counterfeiting Technology
 [PDF]

熊健会
Applied Physics (APP) , 2015, DOI: 10.12677/APP.2015.512025
Abstract:
本文采用化学共沉淀的方法合成了Tb3+/Eu3+共掺杂的CaMoO4荧光粉。通过X射线衍射仪(XRD)和场发射扫描电镜(FE-SEM)对样品的晶体结构和形貌进行了表征,测量了各样品的发射光谱和激发光谱,通过光谱发现Tb3+到Eu3+存在着能量传递,计算了各样品分别在274 nm、394.5 nm和486 nm激发下的色坐标,通过计算和比较色坐标的标准差,发现当Tb3+掺杂浓度为5%,Eu3+掺杂浓度为0.5%时样品色坐标的标准差最大,说明此掺杂浓度下的荧光粉的颜色随激发波长变化最明显,表明此掺杂浓度下的荧光粉可能应用于防伪技术领域。
Series of CaMoO4: Tb3+, Eu3+ phosphors were prepared by the method of precipitation. The structure and morphology of the phosphors were characterized by the X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The photoluminescence properties of the prepared products were researched, find the energy can transfer from Tb3+ to Eu3+. Calculated the color coordinates of the phosphors under the excitation of 274 nm, 394.5 nm and 486 nm, by calculating and comparing the standard deviation of the color coordinates, when the concentration is 5% Tb3+, 0.5% Eu3+, the standard deviation of the color coordinates is the maximum. Illustrating the doping concentrations of phosphor color change with excitation wavelength is the most obvious. It is indicated that the fluorescent powder may be used in the field of anti-counterfeiting technology.
DFT-Quantum Spectroscopic Studies and Anti-Cancer Effect of Ibuprofen Drug and Some Analogues  [PDF]
Anwar El- Shahawy, Hana Gashlan, Safaa Qusti, Ghada Ezzat, Hossam Emara
Computational Chemistry (CC) , 2016, DOI: 10.4236/cc.2016.42004
Abstract: From our DFT calculations of Ibuprofen drug (IBF) and other related molecules such as 2-Phenylpropanoic acid (2-PPA) and 3-Phenylpropanoic acid (3-PPA), it has been found that the ionization potential energies of their anions are decreased strongly, with respect to their values in the molecular forms, rendering them as spontaneous electron donor which can compensate the electron deficiency for the positive cancer cells. Time dependent calculations show good coincidence with the experimental absorption spectra. Some complexes of IBF are prepared with Cu++ and Zn++ ions. The ratio between the M++ and the ligand (IBF) is 1:2 which has been verified by atomic absorption spectra and elemental analyses. Their spectral studies have been performed in different solvents of different polarities. The metabolite products of IBF have been studied from DFT calculations point of view and it has been concluded that the consistency of the ionization constants and the electron affinities of them with those of the nucleic acid bases prevents the electron transfer between them therefore they are safe for the human body from cancer diseases.
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