通过带有磁性杂质介观环传输的Aharonov-Casher振荡     

曹秀凤  宋小龙  汪源  施耀铭 《上海大学学报(英文版)》2004,8(1)

Aharonov-Casher oscillasions of transmission through a mesoscopic ring with a magnetic impurity is investigated.Both spin-dependent transmission and reflection coefficients of spin-state electrons at zero-temperature are calculated as a function of the textured electric fields and its title angle in the present of spin-flipper scattering.It is found that the spin-exchange interaction can destroy intermittently periodic oscillations of spin-up transmission and reflection coefficients within some small ranges in the adiabatic region of quantum phase.However spin-down transmission and reflection coefficients appear periodic AC oscillations.The calculated results manifest that spindown transmission and reflection coefficients have the same perfect oscillation patterns.In the nonadiabatic region, the behavior of the anomalous AC oscillations are depedent on the difference between the tilt angle of spin and that of texture electric field.  相似文献   

浅谈计算机信息化建设与管理     

于海涛  宋小龙 《黑龙江科技信息》2011,(23):103-103

目前,随着科学技术的迅速发展,计算机信息技术不断被应用于企业的各项日常工作中,它已经由一种单纯的科学技术变成一种提高企业管理水平、增强企业综合竞争力的重要力量,因此如何通过计算机信息化建设和管理来提高企业的生产力水平和经营管理水平,已经成为企业在当前发展阶段必须思考的一项重要课题。主要分析了计算机信息化建设与管理在企业发展中所起到的重要作用,以及企业在计算机信息化建设与管理中仍然存在的一些问题,以此为出发点,进一步思考在未来的发展过程中企业应当如何加强计算机信息化建设与管理,从而在根本上促进企业走上更加科学健康的信息化发展之路。  相似文献   

新媒体背景下传统媒体改版分析     

宋小龙 《采．写．编》2019,(3)

  相似文献   

量子线中通过双杂质的共振传输     

宋小龙  赵志云  汪源  施耀铭 《上海大学学报(英文版)》2003,7(4):361-365

1　Introduction　Quantumtransportinmesoscopicsystemshasbeenextensivelyinvestigatedinthe pasttwodecades[1] .SinceWeesetal[2 ] .andWharametal[3] .discoveredthe phenomenonofconductance quantizationofanelectronthroughanarrow pointcontactstructure ,therehavebeenanumberofotherworkswhichcon centratedonstudyingelectronscatteringfromimpuri tiesinanarrowquantumconductorwire .BagwellandAvishaietal[4 9] .haveexaminedtheinfluencesofscatteringfromimpuritiesontheelectrontransmis sioninquantumwirebyusingthe…  相似文献   

强制分类背景下社区生活垃圾源头分类与综合处理系统减碳效率     

丁猛  宋小龙  白建峰  庄绪宁  赵静  李维明  罗伟 《资源科学》2023,45(1):18-30

【目的】在强制分类背景下,不同分类收集方式会改变生活垃圾物质流向与后续收运处置过程,进而影响回收处理系统的生命周期碳排放和经济表现。本文针对北京社区垃圾源头分类与综合处理系统的不同情景,开展减碳效率分析与优化,为建立因地制宜的垃圾分类收集模式提供科学依据。【方法】采用物质流分析方法（MFA）对回收处理全过程的物质流向和流量进行分析,结合生命周期碳排放量核算（LCCA）和生命周期成本分析（LCC）分别评估碳足迹和经济成本,在此基础上提出减碳效率指标并进行优化分析。【结果】基准情景（S1）和优化情景（S2-S5）的生命周期碳排放量分别为-148.14 kgCO₂e、-236.44 kgCO₂e、-251.25 kgCO₂e、-297.06 kgCO₂e、-343.51 kgCO₂e。相对于S1,4种优化情景均表现为正向的减碳效率,减碳效率值依次为S5(2.20)>S4(1.66)>S3(1.38)>S2(1.31)。S5对应的“垃圾分类驿站+可回收物智能回收箱+垃圾分类指导员”优化模式具有最高的减碳效率。在垃圾综合处理能力和各组分处理能力充足的前提下,随着准确分类比例增加,减碳效率也逐步提升。【结论】源头分类收集体系的建立和完善,增加了前端基础设施运行成本、人力成本和环境影响,但有效提高了后端分类处理效率及再生资源产出率,带来生命周期碳减排效益的提高。随着今后居民垃圾分类自主投放参与率和准确率上升,收集阶段经济成本将大幅降低,减碳效率可进一步提升。  相似文献   

基于旅游屏蔽理论的固原市旅游地形象对策研究     

宋小龙  李陇堂  石磊  高秀云  杨萍 《河北旅游职业学院学报》2017,22(3)

进入21世纪以来,我国旅游产业发展快速,旅游热点区域逐渐凸显,然而热点区域和屏蔽区域分异现象愈加明显,从而影响了全域旅游的发展,再次研究和应用旅游屏蔽理论具有重要的现实意义.通过阐述“旅游屏蔽”对固原市的影响,基于旅游屏蔽理论对固原市旅游形象进行多角度分析,发现固原市旅游发展在旅游形象认知、利益、吸引力等多方面存在屏蔽现象.因此,提出了形成自身特色的“旅游形象叠加”、构架旅游基础设施系统、加大柔性旅游宣传等旅游形象对策.  相似文献   

带有磁性杂质的量子线中自旋相关传输     

汪源  宋小龙  黄豪  施耀铭 《上海大学学报(英文版)》2005,9(6):485-488

1IntroductionQuantumtransport in mesoscopic systems has beenextensively investigated in the past two decade[1].Since Wees ,et al.[2]and Wharam,et al.[3]discov-ered the phenomenon of conductance quantization ofan electron through a narrow two-di mensional con-striction,there have been a number of other works ,which are concentrated on studying electron scatteringfrom i mpurities in a narrow quantum conductorwire[4-10].Bagwell and Avishai ,et al.[4-6]have exam-ined the influences of scattering …  相似文献   

Aharonov-Bohm环中磁场调制的极化电导振荡     

施耀铭  宋小龙 《上海大学学报(英文版)》2002,6(1):50-54

Oscillations of the spin-polarized conductance controlled by a uniform magnetic field in a modified Aharonov-Bohm ring is studied with use of one-dimensional quantum wave guide.Its expression at zero temperature is obtained as a function of the flux penetrating the ring and the magnetic field.It has been found that there are two kinds of polarized conductance extremas for a given Fermienergy.As Zeemann energy of spin-polarized electron in the stub is varied.one kind of extrema exhibits continuous phase shift .However,another is locked at particular values of phase shift and it can only change abrouptly from a maxima to a minima when Zeemann crosses the level of the bound state of isolated stub.This is a different mehanism for abrupt change phase of conductance osillations.  相似文献   

湖北男子体操走出低谷初探     

杜旻  宋小龙 《湖北体育科技》2012,(1):122-124

目的：探讨湖北男子体操如何能尽快的走出低谷。方法：通过古今文献以及国内同行业的比较,分析湖北体操的发展特点。结果：湖北男子体操具备崛起的条件。  相似文献   

Aharonov-Casher Oscillasions of Transmission Through a Mesoscopic Ring with a Magnetic Impurity     

曹秀凤  宋小龙汪源 施耀铭 《上海大学学报(英文版)》2004,8(1):38-42

Aharonov-Casher oscillasions of transmission through a mesoscopic ring with a magnetic impurity is investigated. Both spindependent transmission and reflection coefficients of spin-state electrons at zero-temperature are calculated as a function of the textured electric fields and its title angle in the present of spin-flipper scattering. It is found that the spin-exchange interaction can destroy intermittently periodic oscillations of spin-up transmission and reflection coefficients within some small ranges in the adiabatic region of quantum phase. However spin-down transmission and reflection coefficients appear periodic AC oscillations. The calculated results manifest that spindown transmission and reflection coefficients have the same perfect oscillation patterns. In the nonadiabatic region, the behavior of the anomalous AC oscillations are depedent on the difference between the tilt angle of spin and that of texture electric field.  相似文献