Four constant potential function of amorphous selenium and evaluation of its thermodynamic and acoustic properties

Litov and Anderson after various considerations suggested a four constant potential function for a-Se as well as a-As₂S₃. Hence we also used a four constant potential function with the sole purpose of applying this potential function to obtain several acoustic, thermodynamic and other properties. We calculated several acoustic properties of a-Se like second order elastic constants (SOECs), their pressure derivatives, the longitudinal and transverse Grüneisen constant by two different methods, phonon frequencies, absorption band position through the use of Nath-Smith-Delaunay’s equation, and the thermodynamic properties like heat capacity, bulk modulus, thermal Grüneisen constant, the pressure derivative of the bulk modulus (dK _T/dP=C ₁), the pressure derivative ofC ₁ which is related to Anderson-Grüneisen parameter, pressure derivative of Grüneisen constant namelyγ′ _g which is related to second Grüneisen constant, characteristics of phonon frequencies, potential energy function through the use of fitted parameters and third order elastic constants. Finally we calculatedK _T at the reduced density ofρ/ρ ₀=1.1.K _T is obtained from the potential function with the fitted parameters. In all the above cases the calculated values are found to be in good agreement with experiment wherever available. In this connection it is important to point out that we eliminated ‘C’ a constant in the potential function using the equilibrium condition as was done by Litovet al in a-Se and Gerlichet al in the case of a-As₂S₃ as all amorphous substances are isotropic as mentioned by several authors. We contemplate to calculate several other properties for a-Se and a-As₂S₃ and present them at a later stage.     

The Adsorption Effect of Quaternized Chitosan Derivatives on Bile Acid

Chitosan, which is easily derived from chitin by N-deacetylation. It is well known that hypercholesterolemia has been identified as a major risk factor in the development of atherosclerosis and its clinical sequelae like coronary heart disease and myocard…     

Crystal and Molecular Structure of Hexahydro-2-(Nitro-Benzoylmethylene)Pyrimidine

1INTRODUCTIONHeterocyclicketeneaminalsareversatilestartingmaterialsforthesynthesisofawidevarietyofnewheterocyclesandfusedheterocycles.Thus,thesynthesisandre-actionofheterocyclicketeneaminalshavegivenrisetomuchattention[18i.Recentlynitrationofheterocyclicketeneaminalswasstudied[9i.Wehavepreparedhexahydro-2-(nitro-benzoylmethylene)pyrimidi(1).ItscrystalstructurehasbeendeterminedbyX-raydiffractionmethodandthemolecularstructureisdiscussed.2EXPERIMENTALThesinglecrystalofhexahydro-2-(nitr…     

Approximations to the distribution of the sample correlation matrix

In this article, multivariate density expansions for the sample correlation matrix R are derived. The density of R is expressed through multivariate normal and through Wishart distributions. Also, an asymptotic expansion of the characteristic function of R is derived and the main terms of the first three cumulants of R are obtained in matrix form. These results make it possible to obtain asymptotic density expansions of multivariate functions of R in a direct way.     

富勒烯衍生物的红光光限幅实验

应用钛宝石可调谐脉冲激光,在波长为691nm、脉冲宽度为10ns的条件下,研究了新型富勒烯叠氮乙酰氨衍生物(N-acetamide1,2-dihydro-1,2-azafulerene[60])的光限幅特性。     

Synthesis of A Novel Fulleroaziridine Carrying 4-Deoxy-4''''-demethylepipodophyllotoxin

Functionalization by cycloaddition reactions1 represents a useful strategy to modify fullerenes1,2. Stable cycloadducts are interesting in regarding to the development of new materials with unique physical properties or biological activities3. One of the typical reactions is the cycloadditions of C60 with azide compounds. Wudl and Miyata et al. reported that C60 reacted with alkyl azides4 or benzyl azides5 to give the same kind of adduct azafulleroids with an opened 6,5-ring junction by th…     

Synthesis,Characterization and Crystal Structure of (PhCH2)2Sn(S2CENt2) and (PhCH2)2Sn(S2CNC4H8)2

Two new dibenzyltin bisditiocarbamates(PhCH2)2 Sn(S2CNEt2)2(1) and (PhCH2)2 Sn(S2CNC4H8)2(2) were synthesized by the reaction of dibenzyltin dichloride with dithiocarbamates and characterized by elemental analysis ,IR,^1H NMR and MS spectra.The crystal structures were determined by X-ray single crystal diffraction analysis.In both complexes,the tin atom is six-coordinated in a distorted octahedral configuration.In the crystals of 1,the molecular packing in unit cell reveals that the two adjacent molecules are symmetrically linked to each other in dimers by two Sn S interactions of 0.3816nm.In the crystals of 2,the molecules are packed in the unit cell in one-dimensional chain structure linked by weaker intermolecular S S conmtacts.     

CALCULUS ON CANTOR TRIADIC SET （I）——DERIVATIVE

For real-valued functions defined on Cantor triadic ,set. a derivative with corresponding formula of Newton-Leihniz‘s type is given In particular, for the self-simltar functions and alter-nately jumping functions defined in this paper, their derivative and exceptional sets are studied ac-curately by using ergodic theory on Е2 and Duffin-Scbaeffer‘s theorem coneerning metric diophan-tine approximation. In addition, Haar basis of L2(Е2) is constructed and Flaar expansion of stan-drd self-similar function is given.     

Estimation of the Mean of a Wiener Sheet

A shifted Wiener sheet is observed above a decreasing curve Γ. By the help of a direct discrete approach and under weaker assumptions than in the paper of Arató [Comput. Math. Appl. 33 (1997), 13–25], an explicit formula is derived for the maximum likelihood estimator of the shift parameter. This estimator is a weighted linear combination of the values at the endpoints of the curve Γ and weighted integrals of the observed process and its normal derivative along the curve Γ. This revised version was published online in June 2006 with corrections to the Cover Date.