Analysis of （1, 2） （1, 3） and （2, 3） Bands in the c^3Ⅱu- b^3Ⅱg System of P2

We investigate the high resolution absorption spectroscopy of P2 radical, generated in ac glow discharge of PC13 buffered with helium, using optical heterodyne magnetic rotation enhanced concentration modulation spectroscopy in the visible region. The （1, 2）, （1, 3） and （2, 3） bands of c^3Ⅱu- b^3Ⅱg in the range 16620-17860cm^-1 are observed and their 3II2 3II2 subbands are rotationally analysed. A set of effective molecular constants for the Ω= 2 component of the states involved are determined.     

Die elektrischen Eigenschaften des Kondo-Supraleiters (La,Ce)Al2

In the ternary alloy (La, Ce)Al₂ the Kondo anomalies due to the Cerium impurities are studied in the normal and superconducting state. A vanishing of superconductivity in certain (La, Ce)Al₂ alloys below a second transition temperature has been observed for the narrow range of 0.6–0.7 at% Ce-additions. The transition back into the normal state has been observed by means of dc-conductivity and low frequency mutual inductance measurements down to 30 mK. Curves of the upper critical field versus temperature show a maximum at finite temperatures even for lower Ce-concentrations. The temperature dependence of the pair-breaking parameter has been deduced empirically from the upper critical field curves, assuming additive pair breaking theory. In contradiction to the theory no decrease of the pair-breaking parameter forT → 0 can be observed. Therefore the reentrance of superconductivity at ultra low temperatures cannot be expected.     

Der Zerfall des122Xe (T 1/2=20,l h) und des122J (T 1/2=3,6min)

Theγ spectra emitted in the decay of¹²²Xe and¹²²I have been investigated using Ge(Li) detectors and a Ge(Li)-NaI coincidence apparatus. 14γ transitions with energies between 61.8 and 416.9 keV have been identified in the decay of¹²²Xe, 44 transitions between 564.0 and 3,291.0 keV in the decay of¹²²I. Level schemes having 7 excited levels for¹²²I and 21 excited levels for¹²²Te are proposed.     

Metaplectic Representation of ospq(1/2) Algebra and Basic Hypergeometric Functions

In this paper we use the bosonic realization of osp_q(1/2) algebra to obtain its metaplectic representation. The group element for this algebra is shown to be described in terms of the basic hypergeometric function.     

Crystal structures and phonon modes of Ba(Ca1/2W1/2)O3, Ba(Ca1/2Mo1/2)O3 and Ba(Sr1/2W1/2)O3 complex perovskites investigated by Raman scattering

This work investigates the crystal structures and phonon modes of Ba(Ca_1/2W_1/2)O₃, Ba(Ca_1/2Mo_1/2)O₃ and Ba(Sr_1/2W_1/2)O₃ perovskites by Raman spectroscopy. The samples were produced by conventional solid‐state processing at 1200 °C. X‐ray diffraction showed that single‐phase homogeneous materials were produced, which are cubic or pseudo‐cubic in symmetry. The existing controversies in the literature for these complex perovskites were investigated by comparing experimental Raman data with group‐theory analysis. Ceramics with Ca and W or Mo were found to be cubic, space group Fm3 m. For these materials, four Raman‐active bands were observed and the fitting parameters showed that the Ba(Ca_1/2Mo_1/2)O₃ ceramic presents bands at lower wavenumbers if compared with the Ba(Ca_1/2W_1/2)O₃ sample. For the Ba(Sr_1/2W_1/2)O₃ material, two hypotheses were investigated for monoclinic or triclinic structures. The experimental results showed 12 Raman‐active modes for this ceramic, which is in perfect agreement with the theoretical predictions for a monoclinic (I2/m) structure. Copyright © 2009 John Wiley & Sons, Ltd.     

Bestimmung des (631)K=1/2, I=1/2-Zustandes im U 239

Theγ-ray spectrometer at the DR 3-reactor at Risø was used to investigate the low energyγ-lines of U 239 which are emitted during neutron-capture in U 238. Very closely lying lines have been found between 500 and 650 keV. The big intensity of the 133 keV line and the lack of other transitions of appropriate energy and intensity point out that this line corresponds to the hinderedE 2-transition from the (631)I=1/2⁺ level to the (622)I=5/2⁺ groundstate. A suggestion was made for the decay possibility of the octupole states at 700 keV found by N.Fiebiger.     

Die Form des β-Spektrums des87Rubidiums bei niedrigen Energien,gemessen als Differenz an den Isotopen87Rb und85Rb

The β-spectrum of⁸⁷Rb was measured in a 4 π-proportional counter with very thin sources and backings from 0 to 90 keV. In this region we found more β-particles than other authors. The results confine the nuclear parameters to smaller limits than before. The countings up to 90 keV together with the results of other authors at higher energies lead to an estimated half life between 4.8 and 5.1 · 10¹⁰ years.     

Die Hyperfeinstruktur des angeregten 32P3/2-Zustandes von Natrium

The hyperfine structure of the 3²P_3/2-state in the Na(I)-spektrum was investigated by optical double resonance. Three zero fieldrf-transitions (ΔF=±1, Δm_F=0) were detected and thus the unambiguous interpretation of therf-spectrum was made possible. From an analysis of therf-spectrum one obtains the magnetic hyperfine structure splitting constant a=(18.5 _?0.2 ^+0.6 ) Mc/sec the electric quadrupole interaction constantb=(3.2±0.5) Mc/sec which yields an electric quadrupole moment Q(Na²³)=(0.138±0.025)·10²⁴cm².     

Facile preparation and performance of novel high-TC xBi(Ni1/2Ti1/2)O3-(1-x)Pb(Zr1/2Ti1/2)O3 piezoceramics

High Curie temperature (T_C) xBi(Ni_1/2Ti_1/2)O₃-(1-x)Pb(Zr_1/2Ti_1/2)O₃ (xBNT-(1-x)PZT, BNT-PZT) piezoelectric ceramics were prepared by the conventional ceramic processing. The composition-induced morphotropic phase boundary (MPB) and its influences on structure and electrical performance were investigated. The synthesized BNT-PZT ceramics exhibit rather pure perovskite structure, and densified microstructure morphology with uniform elementals distribution in both grains and grain boundaries. With increasing the content of Bi(Ni_1/2Ti_1/2)O₃ (BNT), crystal structure of the BNT-PZT ceramics transform from tetragonal phase to rhombohedral phase, and dielectric response peaks change from narrow shape to very broad shape but all presenting dielectric frequency dispersion. The diffused and relaxation dielectric behavior can be fitted well by the quadratic law, and the Vogel-Fulcher law fitting provides additional information on the relaxation characteristic. The MPB effects are confirmed further by ferroelectric and piezoelectric properties measurements. High-T_C combined with excellent piezoelectric performance can be realized in the BNT-PZT system, which presents promising applications in geothermal exploration, aerospace and related elevated temperatures fields.     

Effects of strontium on the characteristics of Pb(Zr1/2Ti1/2)O3--Pb(Zn1/3Nb2/3)O3 ceramics

The dielectric and piezoelectric properties of pyrochlore-free lead zirconate titanate-lead zinc niobate ceramics were investigated systematically as a function of Sr doping. The powders of Pb_{(1? x )}Sr _x [0.7(Zr_{1 / 2}Ti_{1 / 2})–0.3(Zn_{1 / 3}Nb_{2 / 3})]O₃, where x?=?0–0.06 were prepared using the columbite-(wolframite) precursor method. The ceramic materials were characterized using X-ray diffraction, dielectric spectra, hysteresis and electromechanical measurements. The phase-pure perovskite phase of Sr-doped PZN--PZT ceramics was obtained over a wide compositional range. The results showed that the optimized electrical properties were also achieved at composition x?=?0.0, which were K _P?=?0.69, d ₃₃?=?670?pC?N^?1, P _r?=?31.9?µC?cm^?2 and ε_rmax?=?18600. Maximum dielectric constant values of the systems decreased rapidly with increasing Sr concentration. Moreover, with increasing Sr concentration dielectric constant versus temperature curves become gradually broader. The diffuseness parameter increased significantly with Sr doping. Furthermore, Sr doping has been shown to produce a linear reduction in the transition temperature (T _m)?=?294.1–12.7x°C with concentration (x). Sr shifts the transition temperature of this system at a rate of 12.7°C?mol^?1%.     

0.90(Bi1/2Na1/2)TiO3–0.05(Bi1/2K1/2)TiO3– 0.05BaTiO3 transducer for ultrasonic wirebonding applications

Lead-free piezoelectric ceramic 0.90(Bi_1/2Na_1/2)TiO₃–0.05(Bi_1/2K_1/2)TiO₃–0.05BaTiO₃ (BNKBT-5) rings (OD=12.7 mm, ID=5.1 mm and 2.3-mm thick) were fabricated and characterized. Four ceramic rings were used as the driving element in an ultrasonic wirebonding transducer and the performance of the transducer was characterized. The lead-free transducer was found to have comparable voltage rise and fall times as a lead-based PZT transducer and has a relatively large vibration amplitude, thus showing that BNKBT-5 has the potential to be used in fabricating lead-free ultrasonic wirebonding transducers. PACS 77.22.Ej; 77.84.-s; 85.50.-n     

钪原子的自电离里德伯能级3d4s(~1D_2)nf~2D_(3/2),3d4s(~1D_2)nf~2F_(5/2)和3d4s(~1D_2)np~2D_(3/2)的理论研究

在多通道量子亏损理论框架下,利用相对论多通道理论,分别在冻结实近似和考虑偶极极化下计算钪原子的Jπ=(3/2)-,(5/2)-的三个收敛于[Ar]3d4s(1D2)的自电离里德伯系列的能级.对3d4s(1D2)np2D3/2和3d4s(1D2)nf2F5/2这两个系列,计算结果表明,考虑偶极极化效应后,理论计算和实验测量的量子数亏损之差普遍小于0.01.而对3d4s(1D2)nf2D3/2系列,考虑偶极极化效应后的结果和仅考虑冻结实的结果比较接近,理论计算和实验测量的量子数亏损之差普遍在0.04左右.     

The Hopf Algebra Structure of GL(1, Hq) and the Isomorphism between SPq(1)and SUq(2)

In this Letter, we introduce the Hopf algebra structure of the quantum quaternionic group GL(1, H₁) and discuss the isomorphism between the quantum symplectic group SP_q(1) and the quantum unitary group SU_q(2).     

Nanoscale multiphase separation at La(2/3)Ca(1/3)MnO3/SrTiO3 interfaces

55Mn nuclear magnetic resonance experiments are reported on a series of fully strained epitaxial La(2/3)Ca(1/3)MnO3 thin films on SrTiO3. We have found evidence of multiple phase segregation into ferromagnetic metallic and nonmetallic regions as well as regions that are nonferromagnetic and insulating. These insulating regions are mainly located close to interfaces and may have a significant impact on the performance of spin-tunnel devices. As a result of phase segregation, the ferromagnetic coupling within the metallic regions is depressed. This accounts for the reduction of the Curie temperature and conductivity in nanometric thin films.     

Specific-heat anomaly caused by ferroelectric nanoregions in Pb(Mg(1/3)Nb(2/3))O3 and Pb(Mg(1/3)Ta(2/3))O3 relaxors

The specific heat of typical relaxors, Pb(Mg(1/3)Nb(2/3))O3 (PMN) and Pb(Mg(1/3)Ta(2/3))O3 (PMT), was measured by adiabatic and relaxation methods between 2 and 420 K. A broad anomaly was found in the specific heat curve over the wide temperature range between 150 and 500 K for PMN, and between 50 and 400 K for PMT, which provides evidence for the formation of ferroelectric nanoregions (FNR) in the paraelectric matrix. The entropy of the anomaly was estimated as 3.3 J K(-1) mol(-1) and 2.9 J K(-1) mol(-1) for PMN and PMT, respectively, which implies an order-disorder-type mechanism for the formation of FNR.     

Ferromagnetic domain structures and nanoclusters in Nd(1/2)Sr(1/2)MnO3

Magnetic domain structures of Nd(1/2)Sr(1/2)MnO3 were investigated by means of low-temperature Lorentz electron microscopy. On cooling, magnetic domain walls started to appear at 250 K, and they were oriented straight along the [100] and [110] directions. With a further decrease in temperature, the volume of each magnetic domain increased with discontinuous domain-wall jumps. A characteristic granular image was observed at around 140 K, near the charge-ordering transition temperature. We consider that this originated from ferromagnetic nanoclusters that appeared in the antiferromagnetic matrix.     

Possible quantum critical point in La(2/3)Ca(1/3)Mn(1-x)Ga x O3

We study the magnetic ground state in La(2/3)Ca(1/3)Mn(1-x)Ga x O3 manganites, where a quantum critical point (QCP) has been theoretically predicted. The metallic ferromagnetic ground state for low Ga doping breaks down for x > or = 0.11, an insulating state being established at low temperatures. Long-range ferromagnetism coexists with short-range magnetic correlations in the concentration range 0.11 < or = x < or = 0.145 while only the short-range correlations survive for x > or = 0.16. We discuss the implications of such a QCP to the physics of manganites and compare to other QCP systems.