排序方式: 共有126条查询结果,搜索用时 897 毫秒
71.
72.
Demet Demir Yusuf ?ahin Muhammet Y?ld?r?m 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,97(3):381-387
This study is related to Compton scattering of photons from a p-Si sample whose surface charge density distributions are changed by an external electric field. The external electric field intensity in the range 0-75 kV/m was used to change the surface charge density distributions of the sample. The sample surface perpendicular to the electric field was selected as the scattering surface. The p-Si sample was bombarded by 59.5 keV γ-photons emitting from an Am-241 point source. The Compton scattered photons at an angle of 90o were detected by an Si(Li) detector. The Compton scattering intensity suddenly increased with the application of the electric field since the applied electric field distorts both the negatively charged scattering center (free electron, bound electron, ionized acceptor) and the positively charged scattering center (hole) and their momentum distribution in the sample. There is a good third-order polynominal relation between the Compton scattering intensity and the increasing (or decreasing) electric field intensity. The results show that the positively charged scattering centers behave like negatively charged scattering centers, but the latter are slightly more effective than the former in the Compton scattering of γ-rays from the sample in the electric field. 相似文献
73.
对机读卡民文信息采集系统的探讨 总被引:3,自引:2,他引:1
针对当前新疆维吾尔自治区招生考务管理工作中急待解决的一个问题,即万卡通数据录入系统(GDRS)只能识别英文,汉文而无法识别民文的问题,设计出在无民文DOS系统的支持下也可以采集民文信息的新方案,本项目1996年在自治区教委立项并研制成功,填补了新疆计算机考务管理工作的空白,在1997年的普通高校招生统一考试,录取工作中推广实用,效果很理想。 相似文献
74.
The present work describes a new protocol for the synthesis of 5-aminoisoxazoles using α-chlorooximes and 2-phenylsulfonyl acetonitrile via green chemistry routes. The titled 5-aminoisoxazoles 3 were further reacted with 4-nitrobenzoyl chloride to obtain 5-amidoisoxazoles with moderate yields. These heterocyclic compounds were tested in vitro MTT study to investigate inhibitive abilities to some cancer cell lines (C3a, L929, T98g and Mcf-7) and compounds 3a, 3c, 3e and 3h showed noticeable cytotoxic property against four cancer cell lines. 相似文献
75.
Muhammet E. Köse 《Theoretical chemistry accounts》2011,128(2):157-164
Various density functional theory (DFT) functionals and semiempirical techniques were used to predict the ionization potentials
of selected conjugated polymers. Ionization potentials at infinite chain lengths were estimated using Meier fit on oligomer
data. Calculated gas-phase ionization potentials with BHandH functional showed good correlation with the experimental data.
The results from the semiempirical techniques do not compare as favorably as the ones obtained from DFT methods. The data
fitting allowed us to estimate the size of “effective ionization length”, which spanned over 20–30 double bonds in the conjugated backbone of the polymer in question. 相似文献
76.
Eyüp Aketin Ilknur Koca Muhammet Burak Kili 《Numerical Methods for Partial Differential Equations》2021,37(1):196-209
In this work, an analytical approximation to the solution of Schrodinger equation has been provided. The fractional derivative used in this equation is the Caputo derivative. The existence and uniqueness conditions of solutions for the proposed model are derived based on the power law. While solving the fractional order Schrodinger equation, Atangana–Batogna numerical method is presented for fractional order equation. We obtain an efficient recurrence relation for solving these kinds of equations. To illustrate the usefulness of the numerical scheme, the numerical simulations are presented. The results show that the numerical scheme is very effective and simple. 相似文献
77.
In this study, two new salicylidene phosphonate ligands (HL1 and HL2) and their metal complexes (Cu2+, VO2+ and La3+) were synthesized and characterized by spectroscopic and analytical methods. The molecular structure of the ligand HL1 was determined by single‐crystal X‐ray diffraction study. In the structure of the ligand, there is an intramolecular phenol‐imine hydrogen bond. The synthesized compounds exhibit only one emission maximum upon excitation at 270–295 nm range. Complexation of the Schiff base ligands with metal ions did not cause a considerable quenching effect. Finally, the complexes prepared were used as catalysts in cyclohexane oxidation under microwave irradiation. The complexes showed high conversion rates (> 90%) for cyclohexane oxidation; however, poor selectivity was observed for all complexes. The La3+ complexes showed better selectivity for cyclohexane → cyclohexanol transformation with about 45% selectivity. 相似文献
78.
Positivity - A real-valued continuous function f on $$[1, \infty )$$ is said to be summable by the logarithmic summability method of integrals (shortly, $$\ell $$ summable) if $$\begin{aligned}... 相似文献
79.
Muhammet Okur Nazmiye Albayrak Ömer Tamer Davut Avcı Yusuf Atalay 《Brazilian Journal of Physics》2018,48(4):398-405
Quantum mechanical calculations of ground state energy, vibration wavenumbers, and electronic absorption wavelengths of N′-[(Z)-(4-methylphenyl)methylidene]-4-nitrobenzohydrazide with C15H13N3O3 empirical formula was performed by using Gaussian 09 program. Becke’s three-parameter exchange functional in conjunction with the Lee-Yang-Parr correlation functional and Heyd-Scuseria-Ernzerhof functional levels of density functional theory (DFT) with the 6-311++G(d,p) basis set were used in the performing of above mentioned calculations. The highest occupied and lowest unoccupied molecular orbital (HOMO and LUMO) energies have been also calculated at the same levels. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Nonlinear optical (NLO) behavior of the title molecule has been examined by the determining of electric dipole moment (μ), polarizability (α), and static first-order hyperpolarizability (β). Finally, molecular electrostatic potential (MEP) surface as well as Mulliken and NBO atomic charges were calculated by using Gaussian 09 program. 相似文献
80.
Shanghua Li Richard Furberg Muhammet S. Toprak Björn Palm Mamoun Muhammed 《Advanced functional materials》2008,18(15):2215-2220
World energy crisis has triggered more attention to energy saving and energy conversion systems. Enhanced surfaces for boiling are among the applications of great interest since they can improve the energy efficiency of heat pumping equipment (i.e., air conditioners, heat pumps, refrigeration machines). Methods that are used to make the state‐of‐the‐art enhanced surfaces are often based on complicated mechanical machine tools, are quite material‐consuming and give limited enhancement of the boiling heat transfer. Here, we present a new approach to fabricate enhanced surfaces by using a simple electrodeposition method with in‐situ grown dynamic gas bubble templates. As a result, a well‐ordered 3D macro‐porous metallic surface layer with nanostructured porosity is obtained. Since the structure is built based on the dynamic bubbles, it is perfect for the bubble generation applications such as nucleate boiling. At heat flux of 1 W cm‐2, the heat transfer coefficient is enhanced over 17 times compared to a plain reference surface. It's estimated that such an effective boiling surface would improve the energy efficiency of many heat pumping machines with 10–30%. The extraordinary boiling performance is explained based on the structure characteristics. 相似文献