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21.
A coherent potential approximation (cpa) for a mixed diatomic linear chain including both mass and force constant changes has been developed. In this case an impurity
atom substituted at a particular site in one of the sublattices couples with two nearest neighbour atoms in the other sublattices.
The diatomic linear chain is therefore considered as a tetratomic linear chain, the size of the unit cell being twice the
original. Thecpa density of states and the dielectric susceptibility have been calculated. The numerical values of the later have been calculated
in theata (averaget-matrix approximation) limit. Comparison of these results with the experimental and other computer calculations show a qualitative
agreement. 相似文献
22.
Drutskoy A Abe K Abe K Abe T Aihara H Akatsu M Asano Y Aulchenko V Aushev T Bakich AM Ban Y Bay A Bedny I Behera PK Bizjak I Bondar A Bozek A Bracko M Browder TE Casey BC Chao Y Cheon BG Chistov R Choi Y Chuvikov A Danilov M Dash M Dong LY Eidelman S Eiges V Gabyshev N Garmash A Gershon T Golob B Haba J Hagner C Handa F Hastings NC Hayashii H Hazumi M Hinz L Hokuue T Hoshi Y Hou WS Huang HC Igarashi Y Iijima T Inami K Ishikawa A Itoh R Iwasaki H Iwasaki M Iwasaki Y Jang HK Kang JH Kang JS 《Physical review letters》2004,92(5):051801
The radiative decay B-->phi K gamma is observed for the first time. The branching fraction for the charged B--->phi K- gamma decay mode is measured to be B(B--->phi K- gamma)=(3.4+/-0.9+/-0.4)x10(-6). The photon energy distribution for the B--->phi K- gamma decay is presented. The signal for the neutral B(0)-->phi K(0)gamma decay mode is not statistically significant and an upper limit, B(B(0)-->phi K(0)gamma)<8.3x10(-6) at 90% C.L., is set. The analysis is based on a data set of 90 fb(-1) collected by the Belle experiment at the e(+)e(-) asymmetric collider KEKB. 相似文献
23.
Fang F Hojo T Abe K Abe K Abe T Adachi I Aihara H Akatsu M Asano Y Aso T Aulchenko V Bakich AM Ban Y Banas E Bay A Behera PK Bizjak I Bondar A Bozek A Bracko M Brodzicka J Browder TE Casey BC Chang P Chao Y Chen KF Cheon BG Chistov R Choi SK Choi Y Choi YK Danilov M Drutskoy A Eidelman S Eiges V Enari Y Fukunaga C Gabyshev N Garmash A Gershon T Golob B Hara T Hastings NC Hayashii H Hazumi M Heenan EM Higuchi T Hinz L Hokuue T Hoshi Y Hou WS Huang HC Igaki T Igarashi Y Iijima T Inami K 《Physical review letters》2003,90(7):071801
We report measurements of branching fractions for charged and neutral B-->eta(c)K decays where the eta(c) meson is reconstructed in the K(0)(S)K+/-pi(-/+), K+K-pi(0), K(*0)K-pi(+), and pp; decay channels. The neutral B0 channel is a CP eigenstate and can be used to measure the CP violation parameter sin(2phi(1). We also report the first observation of the B0-->eta(c)K(*0) mode. The results are based on an analysis of 29.1 fb(-1) of data collected by the Belle detector at KEKB. 相似文献
24.
The electron-phonon interaction in the periodic Anderson model (PAM) is considered. The PAM incorporates the effect of onsite
Coulomb interaction (U) between f-electrons. The influence of Coulomb correlation U on the phonon response of the system is studied by evaluating the phonon spectral function for various parameters of the
model. The numerical evaluation of the spectral function is carried out in the long wavelength limit at finite temperatures
keeping only linear terms in U. The observed behaviour is found to agree well with the general features obtained experimentally for some heavy fermion (HF)
systems. 相似文献
25.
26.
Addition of ionic liquids to aqueous surfactant solutions can alter/modify physicochemical properties of such systems in favorable manner. Changes in the properties of aqueous solutions of a useful nonionic surfactant Triton X-100 (TX-100) are assessed upon addition of 2.1 wt% of a common and popular ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6). It is shown that the solubility of 'hydrophobic' bmimPF6 in aqueous TX-100 increases with TX-100 concentration. This observation combined with the conductivity data strongly indicates partitioning of bmimPF6 into TX-100 micellar phase. Behavior of a variety of molecular absorbance [methyl orange, phenol blue, and N,N-diethyl-4-nitroaniline] and fluorescence [phenyl on the TX-100, pyrene, pyrene-1-carboxaldehyde, 2-(p-toluidino)naphthalene-6-sulfonate, and 1,3-bis-(1-pyrenyl)propane] probes further confirm this observation. Statistically insignificant increase in critical micelle concentration (cmc) and decrease in aggregation number (N(agg)) of TX-100 micelles are observed upon addition of 2.1 wt% bmimPF6. Based on the overall data, it is inferred that ionic liquid bmimPF6 partitions into the TX-100 micellar phase; presence of bmimPF6 both close to the core as well as in the palisade layer of TX-100 micelles is suggested. Presence of favorable interactions (e.g., H-bonding, dipole-induced dipole, among others) between bmimPF6 and TX-100 is proposed to be the reason for these observations. 相似文献
27.
The nucleon electromagnetic form factorsG
E
P
(q2),G
M
P
(q2) and the axial-vector form factor GA(q2) are studied in a relativistic model of independent quarks confined by an equally mixed scalar-vector square root potentialV
q(r)=1/2(1+γ
0)(ar
1/2+ν
0) taking into account the appropriate centre-of-mass corrections. The respective root-mean-square radii associated withG
E
P
(q2) and G
A
(q2) come out as [〈r
2〉
E
P
]1/2=0.86 fm and 〈r
A
2
〉1/2=0.88 fm. Restoration of chiral symmetry in this model is discussed to derive the pion-nucleon form factorG
πNN(q2) and consequently the pion-nucleon coupling constant is obtained asg
πNN(q2)=12.81 as compared tog
πNN(q2)exp⋍13. 相似文献
28.
29.
Several amino acid ester hydrochlorides were reacted with ammonium formate to give N-formyl amino acid esters in good yields. 相似文献
30.
SR Rout B Behera TK Maiti S Mohapatra 《Dalton transactions (Cambridge, England : 2003)》2012,41(35):10777-10783
Magnetic mesoporous amorphous calcium phosphate nanoparticles with a size of 62 nm and abundant -COOH groups on the surface have been prepared by a simple method. The particles show excellent aqueous dispersion stability in physiological pH without any deterioration in hydrodynamic size and zetapotential. By virtue of the carboxylate groups on the surface, the platinum pharmacophore cis-diaquadiamine platinum(ii), folic acid and rhodamine isothiocyanate were conjugated on these magnetic calcium phosphate nanoparticles. The cytotoxicity and internalization efficiency of these nanocarriers have been evaluated on folate receptor overexpressed HeLa cells. These drug loaded nanoagents exhibit elevated cytotoxicity and induce apoptosis in HeLa cells. 相似文献