Raman scattering study of vibrational modes and hole concentration in GaxMn1-xSb

The Raman scattering study of vibrational modes and hole concentration in a ferromagnetic semiconductor Ga1-xMnxSb grown by Mn ion implantation, deposition and post-annealing has been presented. The experiments are performed both in implanted and unimplanted regions before and after etching the samples. The Raman spectra measured from the unimplanted region show only GaSb-like phonon modes. On the other hand, the spectra measured from the implanted region show additional phonon modes approximately at 115, 152, 269, 437 and 659 cm(-1). The experimental results demonstrate that the extra modes are associated with surface defects, crystal disorder and blackish layer that is formed due to Mn ion implantation, deposition and annealing processes. Furthermore, we have determined the hole concentration as a function of laser probing position by modeling the Raman spectra using coupled mode theory. The contributions of GaSb-like phonon modes and coupled LO-phonon plasmon mode are taken into consideration in the model. The hole-concentration-dependent CLOPM is resolved in the spectra measured from the implanted and nearby implanted regions. The hole concentrations determined by Raman scattering are found to be in good agreement with those measured by the electrochemical capacitance-voltage technique.

~(135)La高自旋态的实验研究

利用在束γ谱实验技术 ,通过 12 8Te(10 B ,3n) 13 5La反应研究了 13 5La的高自旋态 .基于γ γ符合关系、γ射线的相对强度和各向异性度的测量结果 ,建立了 13 5La的能级纲图 .在ω≈ 0 .4 0MeV附近 ,观测到基于πh11 2 质子轨道上的负宇称带的带交叉 .比较N =78同中子素链能级结构的系统性 ,认为该带交叉是由一对h11 2 准质子发生转动顺排造成的 .在高自旋态处 ,观测到具有很强M1跃迁、Signature劈裂很小的ΔI =1负宇称带 ,根据系统性认为该带是建立在πh11 2 (νh11 2 ) 2 组态上的γ≈ - 6 0°的扁椭球形变带 .

~(134)Ba能级结构的在束γ谱学研究

利用在束γ谱学技术 ,通过 12 8Te(10 B ,1p3n) 13 4 Ba反应研究了 13 4 Ba的中、高自旋激发态 .实验中采用 9套BGO(AC)HPGe探测器进行了γ γ t符合测量 .基于γ γ符合关系、γ射线的相对强度和各向异性度的测量结果建立了 13 4 Ba的能级纲图 .比较N =78的同中子素链的负宇称能级结构的系统性 ,发现激发能位于 4 14 2keV ,Jπ 值为 11-的能级很可能是与 13 6Ce具有相似内禀结构特征的相似态

~(125)Sb高自旋态:粒子-核芯激发耦合

利用在束γ谱学方法,通过~(124)Sn(~7Li,α2n)反应研究了~(125)Sb的激发态,首次建立了~(125)Sb的高自旋能级纲图,其中包括21条新γ跃迁和14个新能级。发现1970,2110和2470 keV3个能级为同质异能态,基于延迟符合测量确定了它们的寿命范围,并确定其自旋、宇称分别为15/2~-,19/2~-和23/2~+。根据粒子-核芯耦合图像和经验壳模型计算解释了~(125)Sb的能级结构,3个同质异能态的组态分别被指定为πg_(7/2)(×)V(h_(11/2)s_(1/2))_(5~-),πg_(7/2)(×)V(h_(11/2)d_(3/2))_(7~-)和πg_(7/2)(×)V(h_(11/2)~2)_(10~+),

丰中子核~(125)Sb的高自旋态(英文)

利用在束γ谱学方法 ,通过1 2 4 Sn( 7Li,α2n)反应首次研究了丰中子核1 2 5Sb的高自旋态 .建立了自旋达 2 3 2 +、激发能至 2 63 7keV的能级纲图 ,其中包括 2 1条新γ跃迁和 1 4个新能级 .在 1 970 ,2 1 1 0和 2 471keV识别出了 3个同质异能态 ,估计了它们的寿命范围 ,并建议分别具有πg7 2 ν(h1 1 2 s1 2 ) ,πg7 2 ν(h1 1 2 d3 2 ) ,πg7 2 ν(h21 1 2 )三准粒子组态 .根据价质子与1 2 4 Sn核芯激发态的耦合讨论了1 2 5Sb的能级结构 .

~(127)I核的新能级纲图(英文)

利用1 2 4 Sn( 7Li,4n) 1 2 7I反应研究了1 2 7I核的在束γ谱 ,建立了包括 2 5个新能级和 52条新γ射线构成的新能级纲图 .将基于πh1 1 2 粒子态 ( 1 1 2 - )的负宇称能级推高到 ( 3 5 2 - ) ,在较重的1 2 7I核中得到了退耦合能级结构 .由于在两个正宇称带ΔI=2能级系列中观测到了强的带间跃迁 ,建议此带的主要成分为g7 2质子的组态 .另外还观测到了两个正宇称ΔI=2和ΔI=1能级系列 ,它们可能基于πd5 2 的单准粒子带和一个 3准粒子带 .

A New High-Spin Level Scheme of I-128

High-spin states in the odd-odd nucleus I-128 are investigated via the Sn-124(Li-7,3n)I-128 reaction at 28 and 32 MeV beam energies. A new level scheme of I-128 is established up to high-spin states at I-pi = 16, including 48 levels and 72 gamma transitions. The present level scheme is largely different from the one in a recent publication due to identification of several doublet and triplet gamma transitions and their proper placements in the level scheme. The high-spin level structure exhibits no obvious collective properties and is possibly associated with two and multi-quasiparticle configurations.

EXPERIMENTAL INVESTIGATION OF THE STELLAR REACTION S-30(p, gamma)(31) Cl VIA COULOMB DISSOCIATION

The Coulomb dissociation of the proton-rich nuclei Cl-31 was studied experimentally using Cl-31 beams at 58 MeV/nucleon with a lead target. The relative energy between the reaction products, S-30 and proton, was obtained. The first excited state in Cl-31 was observed which is relevant to the resonant capture of stellar S-30(p, gamma)Cl-31 reaction

MEASUREMENT OF TWO-PROTON CORRELATION FROM THE BREAK-UP OF Al-23

Experiments of Al-23 and Mg-22 radioactive beams bombarding a C-12 target at an energy of 60 similar to 70 A MeV have been performed at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility to study the two-proton emission from Al-23 and Mg-22 excited states, respectively. The trajectorie of the decay products, namely Na-21 + p + p from Al-23 and Ne-20 + p + p from Mg-22, are clean identified. The relative momentum and opening angle between two protons in the rest frame of three body decay channels are obtained by relativistic-kinematics reconstruction. The results demonstrate that there are some di-proton emission components from He-2 cluster for the excited Al-23 and Mg-22.

MEASUREMENT OF THE PROTON-PROTON CORRELATION FUNCTION FROM THE BREAK-UP OF Mg-22 AND Ne-20

An experiment of Mg-22 and Ne-20 beams bombarding on a C-12 target at an energy of 60 similar to 70 A MeV has been performed at the RIKEN projectile fragment separator (RIPS)in the RIKEN Ring Cyclotron Facility to study the two-proton correlated emission from Mg-22 and Ne-20 excited states. The two-protons momentum correlation functions have been obtained for Mg-22 and Ne-20, respectively. The trajectories of the Mg-22 decayed products (Ne-20 + p + p) were also measured to get the angular correlations between the two protons in Center of Mass of decaying system by relativistic-kinematics reconstruction. The results exhibit that Mg-22 has the features of He-2 cluster decay mechanism.

Diterpenes, sesquiterpenes, and a C-15-acetogenin from the marine red alga Laurencia mariannensis

In addition to 10 known compounds (7-16), one new brominated diterpene, 10-hydroxykahukuene B (1), two new sesquiterpenes, 9-deoxyelatol (2) and isodactyloxene A (3), one new brominated C-15-acetogenin, laurenmariallene (4), and two new naturally occurring halogenated sesquiterpenes (5 and 6) that were previously obtained as intemediates in a biomimetic synthetic study of rhodolaureol and rhodolauradiol have been isolated and identified from the organic extract of the marine red alga Laurencia mariannensis. The structures of these compounds were established by spectroscopic methods. The antibacterial and antifungal activities of new compounds 1-4 were evaluated.

Halogenated Sesquiterpenes from the Marine Red Alga Laurencia saitoi (Rhodomelaceae)

Four new halogenated sesquiterpenes, 10-bromo-3-chloro-2,7-epoxychamigr-9-en-8a-of (1), 2,10 beta-dibromochamigra-2,7-dien-9 alpha-ol (2), (9S)-2-bromo-3-chloro-6,9-epoxybisabola-7(14),10-diene (3), and (9R)-2-bromo-3-chloro-6,9-epoxybisabola-7(14),10-diene (4), were characterized from the marine red alga Laurencia saitoi. In addition, two known halosesquiterpenes, 2,10-dibromo-3-chlorochamigr-7-en-9 alpha-ol (5) and isolaurenisol (6), were also isolated and identified. Their structures were established on the basis of extensive analysis of spectroscopic data.

Three-stage transformation of chlorophyll transient fluorescence pattern under sustained dehydration and the discovery of critical water content in seaweeds

The chlorophyll fluorescence kinetics of marine red alga Grateloupia turutunt Yamada, green alga Ulva pertusa Kjellm and brown alga Laminaria japonica Aresch during natural sustained dehydration were monitored and investigated. The pulse amplified modulation (PAM) system was used to analyze the distinct fluorescence parameters during thallus dehydration. Results proved that the fluorescence kinetics of different seaweed all showed three patterns of transformation with sustained water loss. These were: 1) peak kinetic pattern (at the early stage of dehydration fluorescence enhanced and quenched subsequently, representing a normal physiological state). 2) plateau kinetic pattern (with sustained water loss fluorescence enhanced continuously but quenching became slower, finally reaching its maximum). 3) Platform kinetic pattern (fluorescence fell and the shape of kinetic curve was similar to plateau kinetic pattern). A critical water content (CWC) could be found and defined as the percentage of water content just prior to the fluorescence drop and to be a significant physiological index for evaluation of plant drought tolerance. Once thallus water content became lower than this value the normal peak pattern can not be recovered even through rehydration, indicating an irreversible damage to the thylakoid membrane. The CWC value corresponding to different marine species were varied and negatively correlated with their desiccation tolerance, for example. Laminaria japonica had the highest CWC value (around 90%) and the lowest dehydration tolerance of the three. In addition, a fluorescence "burst" was found only in red algae during rehydration. The different fluorescence parameters F-o, F-v and F-v, F-m were measured and compared during water loss. Both F-o and F-v increased in the first stage of dehydration but F-v/F-m. kept almost constant. So the immediate response of in vivo chlorophyll fluorescence to dehydration was an enhancement. Later with sustained dehydration F-o increased continuously while F-v decreased and tended to become smaller and smaller. The major changes in fluorescence (including fluorescence drop during dehydration and the burst during rehydration) were all attributed to the change in F-o instead of F-v This significance of F-o indicates that it is necessary to do more research on F-o as well as on its relationship with the state of thylakoid membrane.

Terpenes and polybromoindoles from the marine red alga Laurencia decumbens (Rhodomelaceae)

Two new brominated diterpenes, namely, laurendecumtriol (1) and 11-O-deacetylpinnaterpene C (2), one new polybromoindole, 2,3,4,6-tetrabromo-1-methyl-1H-indole (7), and six known natural products were isolated and identified from the marine red alga Laurencia decumbens. Their structures were elucidated on the basis of detailed spectroscopic and mass-spectrometric analysis as well as by comparison with literature data. Based on 2D-NMR experiments, the previously reported NMR data for pinnaterpene C (3) were reassigned.

Simulation of the ocean surface mixed layer under the wave breaking

A one-dimensional mixed-layer model, including a Mellor-Yamada level 2.5 turbulence closure scheme, was implemented to investigate the dynamical and thermal structures of the ocean surface mixed layer in the northern South China Sea. The turbulent kinetic energy released through wave breaking was incorporated into the model as a source of energy at the ocean surface, and the influence of the breaking waves on the mixed layer was studied. The numerical simulations show that the simulated SST is overestimated in summer without the breaking waves. However, the cooler SST is simulated when the effect of the breaking waves is considered, the corresponding discrepancy with the observed data decreases up to 20% and the MLD calculated averagely deepens 3.8 m. Owing to the wave-enhanced turbulence mixing in the summertime, the stratification at the bottom of the mixed layer was modified and the temperature gradient spread throughout the whole thermocline compared with the concentrated distribution without wave breaking.