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排序方式: 共有282条查询结果,搜索用时 15 毫秒
1.
We develop an approach to the solution of the spinless Bethe-Salpeter equation for the different-mass case. Although the calculations are developed for spinzero particles in any arbitratry spherically symmetric potential, the non-Coulombic effective power-law potential is used as a kernel to produce the spin-averaged bound states of the non-self-conjugate mesons. The analytical formulas are also applicable to the self-conjugate mesons in the equal-mass case. The flavor-independent case is investigated in this work. The calculations are carried out to the third-order correction of the energy series. Results are consistent with those obtained before. 相似文献
2.
Bound States of the S-Wave Equation with Equal Scalar and Vector Standard Eckart Potential
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Eser Olgar Ramazan Koc Hayriye Tutunculer 《中国物理快报》2006,23(3):539-541
A supersymmetric technique for the bound-state solutions of the s-wave Klein-Gordon equation with equal scalar and vector standard Eckart-type potential is proposed. Its exact solutions are obtained. Possible generalization of our approach is outlined. 相似文献
3.
A porphyrazine based supramolecule with a nonanuclear structure has been prepared by the ready coordination of pyridine donor sites in octakis(4-pyridoxyethylthio)porphyrazinatomagnesium with vanadyl bis(acetylacetonate) and characterized by EPR spectroscopy. 相似文献
4.
Dan Donescu Sever Serban Kristiana Gosa Cristian Petcu 《Central European Journal of Chemistry》2005,3(1):10-27
The possibility to prepare hybrids made by poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA) and/or poly(ethyl
acrylate) (PEtA) with TiO2 was studied. The processes of polymer formation-radical polymerization and sol-gel process for inorganic network —were achieved
simultaneously. Due to a high reactivity of titanium isopropoxide (TIP) in the sol-gel process, a complexant comonomer, allyl
acetoacetate (AlAcAc), was used. Covalent bonds between polymer and inorganic chains were obtained by addition of trialkoxysilane
derivates with vinyl (VTES) or methacryloyl (MPTS) groups. The presence of TIP inhibits the radical polymerization of vinyl
acetate (VAc). The PVAc-TiO2 hybrids were produced by the sol-gel process of TIP in the presence of pre-obtained PVAc. Except for VTES and MPTS, trialkoxysilane
derivates with methyl (MeTES), octyl (OTES) and phenyl (PTES) groups were used. The thermal stability of hybrids is strongly
affected by TiO2 presence and by the type of trialkoxysilane derivates. The thermal stability of PVAc hybrids decreases in the presence of
TiO2 inorganic network. The glass transition temperature of polymers increases in the presence of the inorganic network. 相似文献
5.
Fifty-seven values for the ortho-benzylic coupling constant 4JMe? C?C? H (henceforth denoted as 4JOB) were obtained for a variety of heteroaromatic systems. It was shown that a good correlation exists between 4JOB when the methyl group is not α to the heteroatom and the SCF-MO bond order. This method can therefore be used as an experimental means of determining bond orders in heteroaromatic systems. An examination of bond alternation in thirteen heteroaromatic systems has given a measure of relative “degree of aromaticity” for a larger number of systems than previously reported by any single method. 相似文献
6.
Cengiz Soykan Ramazan Coskun Ali Delibas Ertan Sahin 《高分子科学》2007,(5):491-500
2-Acrylamido-2-methy1-1-propanesulfonic acid(AMPS),and maleic acid(MA)copolymerized with different feed ratios using N,N-dimethylformamide as a solvent and benzoyl peroxide(Bz_2O_2)as an initiator at 70℃.Structure and composition of copolymers for a wide range of monomer feed were determined by elemental analysis(content of N for AMPS-units).Monomer reactivity ratios for AMPS(M_1)-MA(M_2)pair were determined by the application of conventional linearization methods such as Fineman-Ross(F-R),Kelen-Tüd(?)s(KT)and Extended Kelen-Tüds(EKT)and a nonlinear error invariable model method using a computer program RREVM.The characterizations were done by Fourier transform infrared spectroscopy(FTIR),differential scanning calorimetry(DSC)thermal gravimetry analysis(TGA),and and X-ray diffraction.The antimicrobial effects of polymers were also tested on various bacteria,and yeast. 相似文献
7.
Toby M. Chapman Ramazan Benrashid 《Journal of polymer science. Part A, Polymer chemistry》1990,28(13):3685-3699
Block copolyurethanes with N-alkylated polyurethanes as nonself-associating soft segments are prepared. The polymers compare well in hydrolytic stability with block copoly(N-alkylamide urethane)s prepared in an earlier study but have better dimensional stability on exposure to moist heat. They show comparable hydrolytic stability and better oxidative stability than a poly(ether urethane) from the earlier study. The effect of different alkyl substituents on tensile properties and thermostability is studied. The tensile properties are also examined as a function of soft-segment molecular weight at constant weight-percent of hard-block. It is shown that yield stress and ultimate stress increase and elongations decrease as the soft-block M?n increases. DSC measurements do not generally show well defined endotherms with few exceptions but dynamic mechanical testing of some samples does show transitions between 14 and 23°C. 相似文献
8.
Energy states of the Hulthen plus Coulomb-like potential with position-dependent mass function in external magnetic fields
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We need to solve a suitable exponential form of the position-dependent mass(PDM) Schr?dinger equation with a charged particle placed in the Hulthen plus Coulomb-like potential field and under the actions of the external magnetic and Aharonov–Bohm(AB) flux fields. The bound state energies and their corresponding wave functions are calculated for the spatially-dependent mass distribution function of interest in physics. A few plots of some numerical results with respect to the energy are shown. 相似文献
9.
Ramazan Turkmen Vehbi E. Paksoy Fuzhen Zhang 《Linear algebra and its applications》2012,437(6):1305-1316
We show some majorization inequalities and apply them to derive norm, eigenvalue, singular value, and trace inequalities of matrices. We also present a generalization and a different proof of a recent result on majorization concerning partitioned Hermitian positive semidefinite matrices. 相似文献
10.
Dan Donescu Liana Fusulan Stela Lungoci Sever Serban Cristian Peteu 《Journal of Dispersion Science and Technology》2013,34(5):647-653
ABSTRACT The modification of decomposition rate of the potassium persulfate initiator during the synthesis of “two-stage latexes” polystyrene-ethyl acrylate (EtA) of butyl acrylale (BuA) and of 2-ethylhexyl acrylate (EHA) is studied. This rate is minimum for BuA and maximum for EHA, in good agreement with the value of solubility parameters. The appearance of poryacrvlaf.es determines the existence of water bonded to the polar polymer. The amount of water bonded increases in the sequence PEtA?PBuA?PEHA, function of the modification of the diameters of the particles resulted from the latexes obtained. 相似文献