关于Hirota-Satsuma系统初值问题的局部和整体适定性

本文利用ＫＤＶ方程所对应的线性方程解所具有的光滑效应及压缩映像原理,得到了Ｈｉｒｏｔａ－Ｓａｔｓｕｍａ系统初值问题的局部和整体适定性结果．     

Overlapping B3Π0u ← X1Σ g/+ and 1Π1u ← X1Σ g/+ non-radiative characteristic of Br2 vapour in the wavelength region 505–541 nm

The vibronic vapour phase photoacoustic spectrum of Br₂ in the wavelength region 505–541 nm (19796–18480 cm⁻¹) has been recorded using microphone as well as pump-probe method. Discrete vibronic bands superimposed on a monotonically increasing continuum background towards the dissociation limit results from the overlapping B ³Π _0u ^/+ ← X ¹Σ _g ^/+ and ¹Π_1u ← X ¹Σ _g ^/+ electronic transitions. Vibronic bands originating from υ″=0 have been used to estimate the relative rate of non-radiative relaxation as a function of the excited state B ³Π_0u vibrational quantum number υ′. A comparison with the optical absorption spectroscopy of Br₂ leads to the identification of three broad spectral regions between 505 and 541 nm (19796 and 18480 cm⁻¹) on the basis of different non-radiative relaxation processes.     

有机磷化合物的研究XIX.III亚磷酸二烷基酯钠的相转移催化P-烷基化反应

Sodium dialkyl phosphite reacts with non-activated alkyl halide in the presence of crown ether to give dialkyl alkyl phosphonate in moderate yield. Little or no reaction takes place in the absence of crown ether under the same conditions. In all cases, crown ether was present in catalytic amts. indicating that it behaves as a phase transfer catalyst between solid and liquid phases. The influences of structures of crown ethers, alkyl halides, dialkyl phosphites and the nature of solvent on the P-alkylation of sodium dialkyl phosphite have been investigated.     

High spin spectroscopy of 139Pr

The high spin states in N=80 ¹³⁹Pr have been investigated by in-beam γ-spectroscopic techniques following the reaction ¹³⁰Te (¹⁴N, 5n) reaction at E=75 MeV, using a gamma detector array, consisting of seven 23% compton-suppressed high purity germanium detectors and a multiplicity ball of fourteen bismuth germanate elements. Based on γ-γ coincidence data, the level scheme of ¹³⁹Pr has been considerably extended up to 7.2 MeV excitation. Tentative spin-parity assignments are done for the newly proposed levels on the basis of the DCO ratios corresponding to strong gates and the available information from the earlier light ion experiments.     

Effect of doping Ca on polaron hopping in LaSr2Mn2O7

From the transport studies in the bilayer manganites LaSr_2−x Ca _x Mn₂O₇, we have found the variable-range hopping model proposed by Viret et al to be inadequate to describe the transport of charge in these materials. The polarons appear to hop to their nearest neighbors with an activation energy, which in part is dependent on the magnetic interactions in the lattice.     

Discussion on a possible neutrino detector located in India

We have identified some important and worthwhile physics opportunities with a possible neutrino detector located in India. Particular emphasis is placed on the geographical advantage with a stress on the complimentary aspects with respect to other neutrino detectors already in operation.     

A new salicin derivative from the stem bark of Populus davidiana

Phytochemical study on the BuOH-soluble fraction of the stem bark of Populus davidiana resulted in the isolation of a new salicin derivative(1),named davidianoside.The structure was elucidated on the basis of extensive physicochemical and spectroscopic analyses.     

Parity of the band head at 3710 keV in 99Rh using clover detector as compton polarimeter

Clover detector has been used as a Compton polarimeter to measure the linear polarization of γ-rays produced in heavy ion fusion reaction. The polarization sensitivity of the clover detector has been measured over γ-ray energies ranging from 386 to 1368 ke V. The E1 multipolarity of the 1117 keV transition in ⁹⁹Rh has been established using this polarimeter. This has resulted in the assignment of negative parity to the band head at 3710 keV in ⁹⁹Rh.     

Fluctuation conductivity in cuprate superconductors

We have measured the in-plane resistivity of Bi₂Sr₂CaCu₂O_8+δ and Tl₂Ba₂ CaCu₂O_8+δ single crystals in the temperature range 70–300 K. The thermodynamic fluctuations in the conductivity of both the samples start around ∼ 125 K. We find the Lawrence and Doniach [1] model to be inadequate to describe the fluctuation conductivity in these materials. The modification suggested by Ramallo et al [4] where by the conductivity is enhanced due to the presence of two superconducting layers in each unit cell is also not adequate. We suggest the fluctuation conductivity to be reduced due to the reduction in the density of states (DOS) of the quasiparticles which results due to the formation of Cooper pairs at the onset of the fluctuations. The data agrees with the theory proposed by Dorin et al [5] which takes into account this reduction in DOS.