检索结果-南通市图书馆

Gamma Vibrational Bands and Chiral Doublet Bands in A≈100 Neutron-rich Nuclei

在线全文

学校读者我要写书评

暂无评论

原子核物理评论 2009年第S1期26卷 64-69页

作者： J.H.Hamilton A.V.Ramayya J.K.Hwang J.O.Rasmussen s.frauendorf V.Dimitrov Department of Physics Vanderbilt University Lawrence Berkeley National Laboratory Physics Department Notre Dame University

The level structures of neutron-rich 105Mo,106Mo,108Mo and 110Ru nuclei in A ≈ 100 region have been carefully investigated by coincidence measurements of the prompt γ-rays populated in the spontaneous fission of 252Cf with the Gammasphere detector array. In 105Mo,one-phonon K=9/2 and two-phonon K=13/2 γ-vibrational bands have been identified. In 108Mo,one-phonon γ-vibrational band is expanded and two-phonon γ-vibrational band has been identified. Two similar sets of bands in 106Mo and 110Ru are observed to high spins,which have been proposed as the soft chiral γ-vibrational bands. The characteristics for these γ-vibrational bands and chiral doublet bands have been discussed.

关键词： high spin state neutron-rich nucleus γ-vibrational band chiral doublet band

质子数Z分别位于Ru之上和之下的A～(100～126)丰中子原子核三轴形变在原子核形状变迁和共存中的重要作用(英文)

在线全文

学校读者我要写书评

暂无评论

原子核物理评论 2015年第1期32卷 1-23页

作者：罗亦孝 J.H.Hamilton J.O.Rasmussen A.V.Ramayya s.frauendorf 王恩宏 J.K.Hwang 王建国李红洁杨韵颐朱胜江刘艳鑫焦长峰梁午阳石跃许甫荣孙扬刘少华 N.T.Brewer I.Y.Lee G.M.Ter-Akopian A.V.Daniel Yu.Oganessian M.A.stoyer R.Donangelo 马文超 Physics Department Vanderbilt University Lawrence Berkeley National Laboratory Department of Chemistry U.C.Berkeley Department of Physics University of Notre Dame Institut für strahlenphysik FZD-Rossendorf Department of Physics Tsinghua University school of science Huzhou Teachers College school of Physics Peking University Department of Physics and Astronomy Shanghai Jiao Tong University Institute of Modern Physics Chinese Academy of Sciences Chemistry Department University of Kentucky Physics Division Oak Ridge National Laboratory Flerov Laboratory for Nuclear Reactions JINR Lawrence Livermore National Laboratory Instituto de Fisica Facultad de Ingenieria Physics Department Mississippi State University

基于Ru(Z=44)丰中子同位素中存在最大三轴形变的理论预言和实验证据,综述了近年来Rh(Z=45),Pd(Z=46),Ag(Z=47),Cd(Z=48)(质子数Z位于Ru,Z=44之上)及Zr(Z=40),Nb(Z=41),Mo(Z=42),Tc(Z=43)(质子数Z位于Ru,Z=44之下)的A～(100～126)丰中子同位素中关于三轴形变的形状变迁和形状共存系统性研究的重要进展。252Cf自发裂变瞬发γ射线γ-γ-γ三重符合、特别是新建立的γ-γ-γ-γ四重符合数据的系统观测和研究,在Ru,Pd,Cd和Nb丰中子同位素中显著扩展或首次观测到了一系列能带,为这个核区原子核形状的研究提供了新的、重要的实验数据。联系此前报道的有关进展,使用PEs,TRs,PsM,CCCsM和sCTAC理论模型计算拟合新的实验数据,在该核区沿同中素和同位素链,并随自旋和激发能变化各自由度,跟踪原子核形状渐进变化,获得了新的系统性研究成果,显著扩展和深化了人们对原子核形状变迁和形状共存的认知。对于Ru及其上的Rh(Z=45),Pd(Z=46),Ag(Z=47)和Cd(Z=48)丰中子同位素的研究表明:Rh丰中子核具有比最大值稍小的三轴形变,γ=-28°,并在103–106Rh同位素链上鉴别出了手征对称破缺;在三轴形变核112Ru和114Pd(N=68)中发现了三轴原子核的摆动运动,该摆动运动也可能在114Ru(N=70)中存在;观察到了从具有最大三轴形变的110,112Ru中手征破缺到稍小三轴形变的112,114,116Pd中扰动的手征破缺的过渡;在较软的Ag核中观察到了丰富的谱学结构,在104,105Ag中鉴别出了可能的手征对称破缺,在较重的115,117Ag中提出了趋于三轴形变的γ软度;具有小形变的Cd核的能级结构被解释为准粒子耦合、准转动和软三轴形变;最近的库伦激发的研究提供了Z=50,N=82满壳附近122,124,126Cd核中出现核集体性的实验和理论证据;上述研究成果展现出从Ru中的最大三轴形变(γ=-30°,三轴形变极小增益为0.67 Me V),经具有大三轴形变的Rh核(γ=-28°),到Pd核中的稍小、但稳定于中等自旋到高自旋区的三轴形变(γ～-41°,三轴形变极小增益为0.32 Me V),再经Ag核中的γ软度,最后到具有很小形变、但仍出现集体性质、包括软三轴形变的Cd核的过渡。对于Pd核转动带交叉系统性的研究揭示了其第一带交叉(νh11/2)2中子转动顺排的上行γ驱动,和第二带交叉(πg9/2)2质子转动顺排的下行γ驱动效应,成功地解释了114Pd中的三轴摆动运动,并给出了110-118Pd同位素链中理论早已预言、而比早期理论预言更为完整准确的形状渐进变迁和形状共存的图像。根据该核区的系统研究,发现最大三轴形变出现在112Ru,而在相邻的偶Z(Pd)同位素链,三轴形变极小的中心在114Pd,两者均为N=68。上述系统性研究沿相邻的Ru和Pd偶Z同位素链,在N=68同中素中鉴别出最大三轴形变,均比理论预言的108Ru和110Pd多4个中子。在Z值位于Ru(Z=44)之下的Zr(Z=40),Nb(Z=41),Mo(Z=42)and Tc(Z=43)丰中子同位素中,Y和Zr核具有很强的轴对称四极形变,而在较重的Zr同位素中出现了γ自由度;较重的Nb核(A=104～106)基态具有中等程度的软三轴形变和强四极形变,随着自旋和激发能的增加,过渡到接近于轴对称的强四极形变;而较轻的Nb核(A 103)基态均接近轴对称形状;在Nb同位素链上基态由球形到强四极形变的形状突变发生在100Nb(N=59),在100–106Nb同位素链中基态的软三轴形变随中子数增加而增加;在Nb核中还观察到关于软三轴形变的形状共存;Mo核具有大的三轴形变,观察到了γ振动和手征对称破缺;Tc核具有比最大值稍小的三轴形变,γ=-26°,并观察到了手征对称破缺。质子数Z从41到48的A～(100～126)丰中子同位素,特别是Pd和Nb同位素,呈现出关于三轴形变的过渡特征。

关键词：质子数从41到48范围的丰中子核原子核形状变迁和共存长椭球到扁椭球形状变迁三轴形变三轴形变原子核摆动运动原子核手征对称破缺扰动手征态 γ振动能带高自旋态带交叉 γ驱动效应准转动 Z=50和N=82闭壳附近集体性和软三轴形变的出现能级纲图原子核能级自旋/宇称/组态指定位能面(PEs) 投影壳模型(PsM) 总Routhian面(TRs) 推转和组态限制壳模型(CCCsM)和壳修正斜轴推转模型(sCTAC)理论计算自发裂变瞬发γ谱学 γ射线三重和四重符合及角关联测量锎-252 Gammasphere多探测器系统

Gammasphere上裂变丰中子核核结构若干前沿领域的新进展(Ⅱ:第三和第四部分)(英文)

在线全文

学校读者我要写书评

暂无评论

原子核物理评论 2010年第3期27卷 363-389页

作者：罗亦孝 J.H.Hamilton J.O.Rasmussen A.V.Ramayya C.Goodin A.V.Daniel N.J.stone 朱胜江 J.K.Hwang 刘少华 C.J.Beyer 李科 H.L.Crowell D.Al mehed s.frauendorf A.Covello V.Di mitrov 张敬业车兴来姜卓 D.Fong A.Gelberg I.stefanescu A.Gargano E.F.Jones P.M.Gore I.Y.Lee G.M.Ter-Akopian Yu.Ts.Oganessian M.A.stoyer R.Donangelo 马文超 J.D.Cole J.Kormicki 张学谦 s.C.Wu J.Gilat T.N.Ginter s.J.Asztalos Physics Department Vanderbilt University Nashville TN 37235 USA Lawrence Berkeley National Laboratory Berkeley CA 94720 USA Flerov Laboratory for Nuclear Reactions JINR Dubna Russia Joint Institute for Heavy Ion Research Oak Ridge TN 37831 USA Department of Physics Oxford University Oxford OX1 3PU United Kingdom Department of Physics and Astronomy University of Tennessee Knoxville Tennessee 37996 USA Physics Department Tsinghua University Beijing 100084 China Department of Physics University of Notre Dame Notre Dame IN 46556 USA Institut far strahlenphysik FZD-Rossendorf Postfach 510119 D-01314 Dresden Germany Dipartimento di scienze Fisiche Universita di Napoli Federico II and Istituto Nazionale di Fisica Nuclear Complesso Universitario di Monte S. Angelo Via Cintia 80126 Napoli Italy Idaho Accelerator Center Idaho State University Pocatello ID-83209-8263 USA Institut fur Kernphysik Universitat zu Koln 50937 Kdln Germany Department of Chemistry and Biochemistry University of Maryland MD 20742 USA Lawrence Livermore National Laboratory Livermore CA 94550 USA Instituto de Fisica Facultad de Ingenieria C. C. 30 11300 Montevideo Uruguay Mississippi state University Drawer 5167 Mississippi State MS 39762 USA Idaho National Laboratory Bldg. IRCPL MS2114 Idaho Falls ID 83415 USA Department of Physics National Tsing Hua University Hsinchu Taiwan 30013 China National superconducting Cyclotron Laboratory Michigan State University East Lansing Michigan 48824 USA Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA

使用Gammasphere多探测器系统对252Cf裂变源瞬发γ射线进行γ-γ-γ和γ-γ(θ)符合测量,A～100(Z～40,N>56)丰中子核区关于形状过渡、形状共存和形状突变的深入研究获得了新的进展。奇-Z核的系统研究揭示了从Z=39(Y)同位素的轴对称大... 详细信息

使用Gammasphere多探测器系统对252Cf裂变源瞬发γ射线进行γ-γ-γ和γ-γ(θ)符合测量,A～100(Z～40,N>56)丰中子核区关于形状过渡、形状共存和形状突变的深入研究获得了新的进展。奇-Z核的系统研究揭示了从Z=39(Y)同位素的轴对称大四极形变到Z=43(Tc),44(Ru)和45(Rh)同位素中具有中等四极形变之大三轴形变的过渡。Nb(Z=41)同位素具有过渡核的特征。根据邻近同位素和同中素带交叉信息的系统性及推转壳模型(CsM)计算,Tc和Rh偶-N同位素中观察到的带交叉产生于一对h11/2中子的转动顺排。首次观察到100Nb(Z=41,N=59)的高自旋能级纲图和形变态,从而证实了100Nb中的形状共存,并确认,在Nb同位素链上,基态形状突变发生于N=58(球形)到N=59(大形变);而在sr(Z=38),Y(Z=39)和Zr(Z=40)各同位素链上,基态形状突变均发生于N=59(球形)到N=60(大形变)。100Nb具有大形变基态,同现有理论预言相矛盾,其大形变的基态及转动带所具有的很大的和不规则的转动惯量具有重要的理论意义。对奇-质子Cs(Z=55)和La(Z=57)丰中子同位素八极激发的详细研究,发现了141,143,144Cs同位素链上电二极矩D0随中子数增加而减小的急剧变化,此前在145,147La中观察到的电二极矩D0的较缓和的减小似乎亦很陡地下延至148La。在Cs和La同位素中观察到的电二极矩D0的急剧下降很可能同偶-质子核146Ba和224Ra中观察到的电二极矩D0的急剧下降相类似,后者已获反射非对称平均场壳修正理论的成功解释。实验证明,141Cs具有很大电二极矩D0。141Cs和142Xe中观测到的很大的电二极矩D0和仅在141Cs中观察到的电二极矩D0的simplex量子数相关性需要进一步的理论研究。根据转动频率比值ω-(I)/ω+(I)的检定,同Xe同位素一样,认定Cs同位素中包括号143Cs的八极激发为八极振动,而在La同位素中存在八极形变。

关键词：形状过渡轴对称形状三轴形变形状突变带交叉奇-质子八极激发 B(E1)/B(E2)比值电二极矩D0 二极矩的下降八极振动 Cs,La同位素

Disturbance increases high tide travel distance of a roosting shorebird but only marginally affects daily energy expenditure

在线全文

学校读者我要写书评

暂无评论

Avian Research 2019年第3期10卷 294-304页

作者： Hans Linssen Martijn van de Pol Andrew M.Allen Mitzi Jans Bruno J.Ens Karen L.Krijgsveld Magali frauendorf Henk-Jan van der Kolk Department of Animal Ecology Netherlands Institute of Ecology6708PB WageningenThe Netherlands Resource Ecology Group Wageningen University & Research6708PB WageningenThe Netherlands Centre for Avian Population studies Droevendaalsesteeg 106708PB WageningenThe Netherlands Department of Animal Ecology and Physiology Radboud University6500GL NijmegenThe Netherlands sovon-Texel Sovon Dutch Centre for Field Ornithology1790AB Den BurgThe Netherlands Nature Bureau Royal Netherlands Air Force4820BB BredaThe Netherlands

Background:Anthropogenic disturbance can negatively affect an animal's energy budget by evoking movement *** research focuses mainly on immediate displacement as a disturbance effect,since this can be easily observed in the field. However, effects on movement over longer timescales are poorly examined and it is largely unknown if and to what extent they reflect immediate ***-term responses could for example be larger than immediate responses if birds, after disturbance, return to the original location and thereby travel twice the immediate disturbed distance. Methods:We combined GPs tracking data with observational data to quantify the effects of anthropogenic (air force and walkers) and non-anthropogenic disturbances on distances travelled by roosting Eurasian Oystercatchers (Haematopus ostralegus) during the non-breeding season. We compared immediate displacement after a disturbance with distance travelled during the entire high tide period (longer-term response), while accounting for environmental ***,we calculated energy expenditure due to disturbance based on observed disturbance ***:Disturbance resulted in an immediate displacement response of ~200 m (median).Air force disturbances tended to yield larger immediate responses than walker and,especially,than non-anthropogenic ***-term responses and immediate responses were approximately similar,suggesting that,over longer timescales,spatial disturbance effects in the study area remain confined to immediate ***,disturbances were infrequent (0.17 disturbances per bird per hour) and most disturbances were of natural origin (62%).Consequently, anthropogenic disturbance of roosting oystercatchers in the study area on average costs 0.08% of the daily energy expenditure. Conclusions:Our results suggest that immediate spatial responses to disturbance can be a useful proxy for spatial responses over longer *** the non-exha

关键词： Biologging Disturbance Haematopus ostralegus High tide roost Movement ecology shorebird

search for chiral bands in A～110 neutron-rich nuclei

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2009年第S1期33卷 145-147页

作者：朱胜江 J. H. Hamilton A. V. Ramayya J. K. Hwang J. O. Rasmussen 王建国车兴来丁怀博 s. frauendorf V. Dimitrov 徐强顾龙杨韵颐 Department of Physics Tsinghua University Department of Physics Vanderbilt University Lawrence Berkeley National Laboratory Physics Department Notre Dame University

High spin states in A～110 neutron-rich 106Mo, 110Ru and 112Ru nuclei have been reinvestigated by measuring the prompt γ-rays from the spontaneous fission of 252Cf. Two similar sets of bands are observed to high spins in each of three nuclei. Through analyzing of characters of the band structures, the chiral doublet bands are suggested in 106Mo, 110Ru and 112Ru.

关键词： nuclear structure high spin states triaxiality chiral doublet bands