Shell model study of the pairing correlations

A systematic study of the pairing correlations as a function of temperature and angular momentum has been performed in the sd-shell region using the spherical shell model approach. The pairing correlations have been derived for even-even, even-odd and odd-odd systems near N=Z and also for the asymmetric case of N=Z+4. The results indicate that the pairing content and the behavior of pair correlations is similar in even-even and odd-mass nuclei. For odd-odd N=Z system, angular momentum I=0 state is an isospin, t=1 neutron-proton paired configuration. Further, these t=1 correlations are shown to be dramatically reduced for the asymmetric case of N=Z+4. The shell model results obtained are qualitatively explained within a simplified degenerate model

Observation of a γ\gamma-band based on two-quasiparticle configuration in 70^{70}Ge

The structure of $^{70}$Ge has been studied through in-beam gamma ray spectroscopy. A new band structure is identified that leads to forking of the ground-state band into two excited bands. Band structures have been investigated using the microscopic triaxial projected shell model approach. The observed forking is demonstrated to result from almost simultaneous band crossing of the two neutron aligned and the \gamma-band built on this two-quasiparticle configuration with the ground-state band.Comment: 9 pages, 13 figures, Accepted for publication as a Regular Article in PRC. in Physical Review C, 24th Feb 201

Onset of deformation at N=112N = 112 in Bi nuclei

The high spin states in $^{195}$Bi has been studied by $\gamma$-ray spectroscopic method using the $^{181}$Ta($^{20}$Ne, 6n) fusion evaporation reaction at 130 MeV. The $\gamma\gamma$ coincidence data were taken using an array of 8 clover HPGe detectors. The spin and parity assignments of the excited states have been made from the measured directional correlation from oriented states (DCO) ratios and integrated polarization asymmetry (IPDCO) ratios. The results show, for the first time, the evidence of a rotational like band based on a 13/2$^+$ band head in this nucleus, indicating the onset of deformation at neutron number $N = 112$ for the Bismuth isotopes. The results obtained were found to be consistent with the prediction of the total Routhian surface calculations using Woods Saxon potential. The same calculations also predict a change in shape from oblate to triaxial in $^{195}$Bi at high rotational frequency

Radijus utjecaja oborine nad područjem monsuna u Indiji

The paper describes an analysis of rain gauge data to determine an appropriate radius of influence to use for the objective analysis of rainfall over Indian monsoon region. The correlation co-efficient (CC) of rainfall between rain gauges in discrete distance intervals is computed, and the distance at which CC falls to 0.3 is chosen as the radius of rainfall influence. The method is applied for the monthly mean rainfall observations for June, July and August of Indian summer monsoon 2001. The method is also tested for a few case studies in relation to varying geographical and synoptic situations. The study shows that the radius of influence of rainfall over Indian region, in general, is around 200 km, but it has certain day to day variations depending on the prevailing synoptic conditions. The finding of the study is expected to be very useful for the objective analysis of rainfall over Indian region.Ova studija prikazuje analizu mjerenja kišomjernih postaja radi određivanja odgovarajućeg radijusa utjecaja za potrebe objektivne analize oborine nad područjem monsuna u Indiji. Računao se koeficijent korelacije oborine između kišomjernih postaja na diskretnim intervalima te je koeficijent korelacije od 0.3 odabran kao radijus oborinskog utjecaja. Metoda je primijenjena na srednje mjesečne vrijednosti oborine za razdoblje lipanj-kolovoz 2001. tijekom ljetnog monsuna u Indiji. Ova je metoda također testirana na nekoliko odabranih slučajeva zbog variranja geografskih i sinoptičkih situacija. Studija pokazuje da je radijus utjecaja oborine nad područjem monsuna u Indiji općenito oko 200 km, iako postoji određena dnevna varijabilnost koja ovisi o prevladavajućim sinoptičkim uvjetima. Rezultati ove studije korisni su za potrebe objektivne analize oborine nad područjem Indij

Structural study of Cu2−x_{2-x}Se alloys produced by mechanical alloying

The crystalline structures of superionic high temperature copper selenides Cu$_{2-x}$Se ($0 \le x \le 0.25$) produced by Mechanical Alloying were investigated using X-ray diffraction (XRD) technique. The measured XRD patterns showed the presence of the peaks corresponding to the crystalline superionic high temperature $\alpha$-Cu$_2$Se phase in the as-milled sample, and its structural data were determined by means of a Rietveld refinement procedure. After a heat treatment in argon at 200$^\circ$C for 90 h, this phase transforms to the superionic high temperature $\alpha$-Cu$_{1.8}$Se phase, whose structural data where also determined through the Rietveld refinement. In this phase, a very low occupation of the trigonal 32(f) sites ($\sim 3$%) by Cu ions is found. In order to explain the evolution of the phases in the samples, two possible mechanisms are suggested: the high mobility of Cu ions in superionic phases and the intense diffusive processes in the interfacial component of samples produced by Mechanical Alloying.Comment: 2 figures, submitted to Acta Crystallographic

Immobilization of single strand DNA on solid substrate

Thin films based on Layer-by-Layer (LbL) self assembled technique are useful for immobilization of DNA onto solid support. This communication reports the immobilization of DNA onto a solid support by electrostatic interaction with a polycation Poly (allylamine hydrochloride) (PAH). UV-Vis absorption and steady state fluorescence spectroscopic studies exhibit the characteristics of DNA organized in LbL films. The most significant observation is that single strand DNA are immobilized on the PAH backbone of LbL films when the films are fabricated above the melting temperature of DNA. DNA immobilized in this way on LbL films remains as such when the temperature is restored at room temperature and the organization remains unaffected even after several days. UV-Vis absorption spectroscopic studies confirm this finding.Comment: Eight pages, five figure

Small Quadrupole Deformation for the Dipole Bands in 112In

High spin states in $^{112}$In were investigated using $^{100}$Mo($^{16}$O, p3n) reaction at 80 MeV. The excited level have been observed up to 5.6 MeV excitation energy and spin $\sim$ 20$\hbar$ with the level scheme showing three dipole bands. The polarization and lifetime measurements were carried out for the dipole bands. Tilted axis cranking model calculations were performed for different quasi-particle configurations of this doubly odd nucleus. Comparison of the calculations of the model with the B(M1) transition strengths of the positive and negative parity bands firmly established their configurations.Comment: 10 pages, 11 figures, 2 table