四氢β—咔啉类化合物的~(13)C NMR研究

测定了四对新合成的四氢β-咔啉化合物的~13C NMR谱,通过APT,HETCOR和HETCOLOC谱指认了所有碳的归属.所确定的化学位移规律可以用来确定它们的构型.     

Analysis and implementation of cross sync period underwater acoustical positioning techniques for underwater targets

I.IlltroductionWhenanactiveunderwateracousticalpositioningsystemissearchingforanunderwatertarget,itisnecessaryforittocompleteatransmittingandreceivingcycIewithineachworkingperiodinordertofindoutthelocationofthetargetcorrectly.Forexample,whenanunder-wateracoustica1synchronouspositioningsystemistrackinganunderwatertargetwithagivensynchr0nizingperiod,thepropagati0ntimeofthepositioningsignaltravellingfr0mthetaJrgettothearrayofthesystemshouldbelessthanthesynchronizingperiod0therwisetargetdis-tance…     

Toward breast cancer resistance protein (BCRP) inhibitors: design, synthesis of a series of new simplified fumitremorgin C analogues

In this study, we report the design and synthesis of a series of new simplified fumitremorgin C analogues. The preliminary biological study indicated some of these simplified fumitremorgin C might be developed into breast cancer resistance inhibitors.     

Study of the reactions and reaction mechanisms of phosphine (Ph3P) and of phosphite ((PhO)3P) with sulphur (S8)

The reactions of sulphur with phosphine and phosphite were investigated by low-energy electron impact mass spectrometry and fast atom bombardment mass spectrometry. A previously reported mechanism of the Ph₃P–S₈ reaction was supported and a possible mechanism for the (PhO)₃P–S₈ reaction is proposed.     

Cu（Ⅱ）—胱氨酸络合物吸附波的研究及蛋白质中胱氨酸的测定

研究了Cu(Ⅱ)-胱氨酸络合物极谱波的性质;提出了一种用示波极谱法测定蛋白质中胱氨酸的新方法,可在8.0×10~(-4)mol/L Cu~(2+)+8.0×10~(-3)mol/L三乙醇胺的溶液中测定0.05～20mg/L的胱氨酸。     

Application of Lagrangian theorem-based density-functional approximation free of adjustable parameters to nonhard-sphere fluid

A recently proposed parameter free version of a Lagrangian theorem-based density functional approximation (LTDFA) [S. Zhou, Phys. Lett. A 319, 279 (2003)] for hard-sphere fluid is applied to hard-core attractive Yukawa model fluid by dividing bulk second-order direct correlation function (DCF) of fluid under consideration into hard-core part and tail part. The former is treated by the parameter free version of the LTDFA, while the tail part is treated by second-order functional perturbation expansion approximation as done in a recent partitioned DFA [S. Zhou, Phys. Rev. E 68, 061201 (2003)]. Two versions of mean spherical approximation (MSA) for the bulk second-order DCF are employed as input, one is the less accurate plain MSA whose tail part of the second-order DCF is strictly independent of a density argument, the other is the more accurate inverse temperature expansion version of the MSA whose tail part is not strictly independent of the density argument. Calculational results indicate that prediction based on the plain MSA is far more accurate than that based on the inverse temperature expansion version of the MSA. The reason is considered to be that the partitioned DFA requires that the tail part is highly or completely independent of the density argument, the plain MSA, by assuming that the tail part is exactly the potential itself, embodies all of the nonlinearities into the hard-core part which can be treated satisfactorily by the parameter free version of the LTDFA. The present investigation results in a universal method for constructing DFA for nonuniform any nonhard-sphere interaction potential fluids.     

Local solvent density augmentation around a solute in supercritical solvent bath: 1. A mechanism explanation and a new phenomenon

A recently proposed partitioned density functional (DF) approximation (Phys. Rev. E 2003, 68, 061201) and an adjustable parameter-free version of a Lagrangian theorem-based DF approximation (LTDFA: Phys. Lett. A 2003, 319, 279) are combined to propose a DF approximation for nonuniform Lennard-Jones (LJ) fluid. Predictions of the present DF approximation for local LJ solvent density inhomogeneity around a large LJ solute particle or hard core Yukawa particle are in good agreement with existing simulation data. An extensive investigation about the effect of solvent bath temperature, solvent-solute interaction range, solvent-solute interaction magnitude, and solute size on the local solvent density inhomogeneity is carried out with the present DF approximation. It is found that a plateau of solvent accumulation number as a function of solvent bath bulk density is due to a coupling between the solvent-solute interaction and solvent correlation whose mathematical expression is a convolution integral appearing in the density profile equation of the DF theory formalism. The coupling becomes stronger as the increasing of the whole solvent-solute interaction strength, solute size relative to solvent size, and the closeness to the critical density and temperature of the solvent bath. When the attractive solvent-solute interaction becomes large enough and the bulk state moves close enough to the critical temperature of the solvent bath, the maximum solvent accumulation number as a function of solvent bath bulk density appears near the solvent bath critical density; the appearance of this maximum is in contrast with a conclusion drawn by a previous investigation based on an inhomogeneous version of Ornstein-Zernike integral equation carried out only for a smaller parameter space than that in the present paper. Advantage of the DFT approach over the integral equation is discussed.     

Further investigation about Lagrangian theorem-based density functional approximation: test by non-uniform polymer melt

A Lagrangian theorem-based density functional approximation [S. Zhou, New J. Phys. 4 (2002) 36] for hard sphere fluid is employed to describe non-uniform polymer melt in the framework of density functional theory. A required bulk second order direct correlation function (DCF) within the whole density range is obtained by solving the polymer-RISM integral equation, the associated adjustable parameter is specified by a hard wall sum rule, and is found to be a negative value when the bulk density is low and the number of chain segment is large. However, the mathematically meaningless value can be physically meaningful by the observation that the present recipe can produce out density profile in very good agreement with simulation data not only at the contact region, but also at the region far away from the surface, and that the predicted global quantities such as surface excess and surface tension are also in good agreement with the simulation data. It is considered that the LTDFA has a property of self correction, which enables the LTDFA-based DFA for non-uniform polymer melt performs quite well even with a not very accurate second order DCF as input. Potential applications of the self correction peculiarity are discussed.     

Sedimentation equilibrium of colloidal suspensions in a planar pore based on density functional theory and the hard-core attractive Yukawa model

The sedimentation equilibrium of colloidal suspensions modeled by hard-core attractive Yukawa (HCAY) fluids in a planar pore is studied. The density profile of the HCAY fluid in a gravitational field and its distribution between the pore and uniform phases are investigated by a density functional theory (DFT) approach, which results from employing a recently proposed parameter-free version of the Lagrangian theorem-based density functional approximation (Zhou, S. Phys. Lett. A 2003, 319, 279) for hard-sphere fluids to the hard-core part of the HCAY fluid, and the second-order functional perturbation expansion approximation to the tail part as was done in a recent partitioned density functional approximation (Zhou, S. Phys. Rev. E: Stat. Phys., Plasmas, Fluids, Relat. Interdiscip. Top. 2003, 68, 061201). The resultant DFT approach is, thus, the first adjustable parameter-free DFT for HCAY fluids. The validity of the present DFT for HCAY fluids of reduced range parameter z(red) = 1.8 under various external potentials is established in the first of the papers cited previously. The present DFT for HCAY fluids can predict the radial distribution function for the bulk HCAY fluid accurately in the colloidal limit (large value of z(red)), and in the hard-sphere limit, its prediction for the density profile of the hard-sphere fluid in a gravitational field is in very good agreement with the existing simulation data. The dependence of the density profile and distribution coefficient on the magnitude of the interparticle attraction, gravitational field, and degree of confinement is investigated in detail by the present DFT approach. Intuitive and qualitative analyses are also compared with the quantitative DFT calculational results.     

A safe minimum standard,the elasticity of substitution,and the cleanup of the Ganges in Varanasi

Despite repeated calls for a thorough cleanup of water pollution in the Ganges river, there are only two papers in the social sciences by Batabyal and Beladi (2017, 2019) that have shed theoretical light on this cleanup problem and its connection to the sustainability of tourism in Varanasi. Hence, we extend the above‐mentioned analyses and focus on two specific questions. First, we introduce the notion of a safe minimum standard (SMS) into the study and show how to analyze a probabilistic model of the Ganges cleanup problem when the SMS is accounted for. Second, for a representative citizen of Varanasi, we study how the magnitude of the elasticity of substitution between a composite consumption good and water quality in the Ganges—modeled by the SMS—affects the tradeoff between consumption and water quality maintenance.