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THE UNIQUENESS OF MINIMAL SUBMODULE OF VERMA MODULE OVER LIE SUPERALGEBRAS
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作者 戴桂生 《苏州大学学报(自然科学版)》 CAS 1991年第2期125-127,共3页
In this paper , we obtain that, if G is either a basic classical Lie superalgebra of I type or G= B(0, n), every Verma module over G has a unique minimal submodule, And this fails for G=F(4).
关键词 VERMA模 李超代数 唯一性 最小子模
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ON ALMOST PRIME SUBMODULES 被引量:2
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作者 Hani A.Khashan 《Acta Mathematica Scientia》 SCIE CSCD 2012年第2期645-651,共7页
In this article, we define almost prime submodules as a new generalization of prime and weakly prime submodules of unitary modules over a commutative ring with identity. We study some basic properties of almost prime ... In this article, we define almost prime submodules as a new generalization of prime and weakly prime submodules of unitary modules over a commutative ring with identity. We study some basic properties of almost prime submodules and give some characterizations of them, especially for (finitely generated faithful) multiplication modules. 展开更多
关键词 Prime submodules weakly prime submodules almost prime submodules multiplication modules
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INTERSECTION OF PRIME SUBMODULES AND DIMENSION OF MODULES 被引量:1
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作者 A.Azizi 《Acta Mathematica Scientia》 SCIE CSCD 2005年第3期385-394,共10页
The aim of this paper is to study the conditions by which a P-prime sub-module can be expressed as a finite intersection or union of P-prime submodules. Also corresponding to dimension and rank of modules, some equiva... The aim of this paper is to study the conditions by which a P-prime sub-module can be expressed as a finite intersection or union of P-prime submodules. Also corresponding to dimension and rank of modules, some equivalent conditions for a ring to be a Dedekind domain are given. 展开更多
关键词 Dimension of modules multiplication modules prime submodules rank of modules
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The characterization of Γ-modules in terms of fuzzy soft Γ-submodules 被引量:1
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作者 ZHOU Min XIANG Da-jing ZHAN Jian-ming 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2013年第2期217-239,共23页
In this paper,we focus on combining the theories of fuzzy soft sets with Γ-modules,and establishing a new framework for fuzzy soft Γ-submodules.The main contributions of the paper are 3-fold.First,we present the con... In this paper,we focus on combining the theories of fuzzy soft sets with Γ-modules,and establishing a new framework for fuzzy soft Γ-submodules.The main contributions of the paper are 3-fold.First,we present the concepts of(R,S)-bi-Γ-submodules,quasi-Γ-submodules and regular Γ-modules.Meanwhile,some illustrative examples are given to show the rationality of the definitions introduced in this paper.Second,several new kinds of generalized fuzzy soft Γ-submodules are proposed,and related properties and mutual relationships are also investigated.Third,we discover some intrinsic connections between the generalized fuzzy soft Γ-submodules presented in this paper and crisp Γ-submodules,and describe the relationships between regular Γ-modules and the generalized fuzzy soft Γ-submodules presented in this paper. 展开更多
关键词 Fuzzy soft set Γ-module (∈ γ γ q δ)(resp. (■ γ γ δ))-fuzzy soft left R-Γ-submodule(right R-Γ-submodules (R S)-bi-Γ-submodule quasi-Γ-submodule regular Γ-module
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The Primary Radical of a Submodule
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作者 Lamis J. M. Abulebda 《Advances in Pure Mathematics》 2012年第5期344-348,共5页
In this paper we introduced a definition for the primary radical of a submodule with some of its basic properties. We also define the P-radical submodule and review some results about it. We find a method to character... In this paper we introduced a definition for the primary radical of a submodule with some of its basic properties. We also define the P-radical submodule and review some results about it. We find a method to characterize the primary radical of a finitely generated submodule of a free module. 展开更多
关键词 PRIMARY submodule PRIME RADICAL of a submodule RADICAL submodule Free MODULE NOETHERIAN MODULE Finitely Generated submodule
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储能型MMC低频均压混合控制策略
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作者 孙浩 徐友 +2 位作者 赵涛 王春霖 李桂璞 《智慧电力》 北大核心 2024年第5期8-15,共8页
针对低频工况下模块化多电平换流器(MMC)子模块电容电压幅值大幅波动问题,提出1种储能型MMC低频均压混合控制策略,将高频注入与储能型MMC超级电容相结合以有效抑制子模块电容电压的波动。首先分析了MMC低频工况下子模块电容电压波动的原... 针对低频工况下模块化多电平换流器(MMC)子模块电容电压幅值大幅波动问题,提出1种储能型MMC低频均压混合控制策略,将高频注入与储能型MMC超级电容相结合以有效抑制子模块电容电压的波动。首先分析了MMC低频工况下子模块电容电压波动的原因;其次阐述了高频注入和储能型MMC2种抑制低频工况下子模块电容电压的方法;然后提出储能型MMC低频均压混合控制策略,并对其环流进行公式推导。该方法相对于高频注入方法可减小桥臂电流及环流,减少器件电流应力及系统损耗,且相对于储能型MMC方法对超级电容的容值要求降低。最后,通过Matlab/Simulink对储能MMC低频均压混合控制策略进行仿真,验证了所提控制策略的有效性。 展开更多
关键词 模块化多电平换流器 低频控制 子模块均压控制 环流控制
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一种低频储能型MMC子模块电容电压均衡控制策略
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作者 孙浩 徐友 +2 位作者 赵涛 王春霖 李桂璞 《机械与电子》 2024年第1期26-30,36,共6页
针对低频工况下传统MMC子模块电容电压幅值大幅波动的问题,提出一种基于超级电容和双向DC/DC变换器的新型储能MMC低频子模块电容电压均衡控制策略,采用基于子模块整体能量排序算法的双向DC/DC变换器控制超容储能系统,以维持MMC低频工况... 针对低频工况下传统MMC子模块电容电压幅值大幅波动的问题,提出一种基于超级电容和双向DC/DC变换器的新型储能MMC低频子模块电容电压均衡控制策略,采用基于子模块整体能量排序算法的双向DC/DC变换器控制超容储能系统,以维持MMC低频工况下子模块的电容电压稳定。通过MATLAB/Simulink对新型储能MMC低频子模块电容电压均衡控制策略进行仿真研究,仿真结果表明,所提控制策略能够有效抑制低频工况下子模块电容电压的波动。 展开更多
关键词 模块化多电平换流器 低频控制 双向DC/DC控制 子模块电容电压均衡
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基于全桥型MMC的开关序列切换方法及IGBT开路故障诊断策略
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作者 武鸿 王跃 +1 位作者 刘熠 李鹏坤 《高电压技术》 EI CAS CSCD 北大核心 2024年第4期1608-1620,共13页
全桥型模块化多电平换流器(modular multilevel converter,MMC)因具备直流故障穿越能力受到广泛关注,但全桥子模块(full-bridge submodule,FBSM)中更多的开关器件数量对MMC的运行可靠性带来了巨大挑战。针对于此,首先提出了基于全桥型MM... 全桥型模块化多电平换流器(modular multilevel converter,MMC)因具备直流故障穿越能力受到广泛关注,但全桥子模块(full-bridge submodule,FBSM)中更多的开关器件数量对MMC的运行可靠性带来了巨大挑战。针对于此,首先提出了基于全桥型MMC的开关序列(switching sequence,SS)切换方法,通过增加一种子模块(submodule,SM)切除状态,能在不额外增加开关损耗的基础上,使所有类型IGBT开路故障均能够体现故障特性。进一步,分析了所提SS切换方法下的故障特点,并提出了IGBT开路故障诊断策略。所提策略通过判断SS计数是否超出阈值对故障进行检测,并定位故障SM,之后基于SS计数的正负或电容电压变化值进一步辨别故障类型。所提故障诊断策略能够准确检测出IGBT故障,定位出发生IGBT开路故障的SM,并辨别其故障类型,有利于主动运维。此外,所提策略无需额外硬件,并可在一个工频周期(20 ms)内完成对所有故障的准确诊断。最后通过硬件在环平台验证了所提SS切换方法及IGBT开路故障诊断策略的有效性。 展开更多
关键词 模块化多电平换流器 全桥子模块 开路故障诊断 开关序列 故障类型 开关损耗
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模块化多电平变流器IGBT开路故障诊断与定位方法综述
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作者 刘泽浩 肖岚 《中国电机工程学报》 EI CSCD 北大核心 2024年第4期1501-1516,I0021,共17页
随着模块化多电平变流器(modularmultilevel converter,MMC)在工程领域中广泛应用,绝缘栅双极型晶体管(insulated gate bipolar transistors,IGBT)开路故障问题日益突出,并成为制约其稳定运行的主要因素。IGBT开路故障诊断与定位方法作... 随着模块化多电平变流器(modularmultilevel converter,MMC)在工程领域中广泛应用,绝缘栅双极型晶体管(insulated gate bipolar transistors,IGBT)开路故障问题日益突出,并成为制约其稳定运行的主要因素。IGBT开路故障诊断与定位方法作为及时识别开路故障,保证MMC持续稳定运行的主要手段而被广泛研究。文中首先对MMC的基本结构及IGBT开路故障特征进行介绍和分析,阐明故障子模块电流路径及电容电压变化趋势;其次,以定位故障IGBT使用的方法和手段为依据,对国内外相关主要文献进行分类和归纳,总结不同类型故障诊断方法的优点和不足;最后,对MMC开路故障诊断与定位方法的未来发展方向和趋势进行展望,指出基于硬件、基于模型和基于人工智能的3类诊断方案分别在降低硬件复杂度、提高故障诊断准确率和降低计算量等方面应该重点解决的主要问题和思路。 展开更多
关键词 模块化多电平变流器 子模块 IGBT开路故障 故障诊断与定位方法
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新型多端口直流潮流控制器及其控制策略研究
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作者 裘鹏 吴俊健 +3 位作者 陆翌 余敬秋 徐政 郭瀚临 《浙江电力》 2024年第7期86-93,共8页
直流潮流控制器是实现多端直流电网稳态潮流调节的关键装备,针对现有直流潮流控制器的局限性,通过在环形支路中串入输出直流电压可调节的级联子模块的方式,设计了一种新型多端口直流潮流控制器。首先,对所提控制器的拓扑结构和工作原理... 直流潮流控制器是实现多端直流电网稳态潮流调节的关键装备,针对现有直流潮流控制器的局限性,通过在环形支路中串入输出直流电压可调节的级联子模块的方式,设计了一种新型多端口直流潮流控制器。首先,对所提控制器的拓扑结构和工作原理进行了阐述;然后,介绍了其控制策略和参数选择方法;最后,通过一个具有八条直流线路的五端直流电网的电磁暂态仿真案例对直流潮流控制器的性能进行验证。结果表明:所提控制器能够同时调节同一直流母线所连接的多条直流线路上的潮流,具有模块化和易扩展的优势。 展开更多
关键词 多端直流电网 多端口直流潮流控制器 级联子模块 功率平衡 控制策略
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子模块故障下基于变执行频率的MMC功率损耗优化控制
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作者 赵纪峰 谷超越 +3 位作者 杭俊 郭小璇 徐斌 丁石川 《中国电机工程学报》 EI CSCD 北大核心 2024年第3期1133-1143,I0023,共12页
模块化多电平变流器(modular multilevel converter,MMC)因其高度模块化和低谐波失真而逐渐成为最适合大功率应用的拓扑之一。当子模块(submodule,SM)发生故障时,故障桥臂中SM电容电压和开关频率将升高,这会导致MMC故障桥臂的功率损耗... 模块化多电平变流器(modular multilevel converter,MMC)因其高度模块化和低谐波失真而逐渐成为最适合大功率应用的拓扑之一。当子模块(submodule,SM)发生故障时,故障桥臂中SM电容电压和开关频率将升高,这会导致MMC故障桥臂的功率损耗不平衡,从而影响MMC的寿命。文中提出一种基于变执行频率的功率损耗优化控制(variable execution frequency-based power losses optimization control,VEF-PLOC),该控制通过调整电容电压平衡控制的执行频率来调节功率器件的开关损耗,从而优化故障桥臂中功率器件的损耗。提出的VEF-PLOC能够优化SM故障下故障桥臂功率损耗,从而有效地提高MMC的寿命。最后,在时域专业工具PSCAD/EMTDC上进行仿真,并在小型MMC样机上进行实验,仿真和实验结果皆验证了提出的VEF-PLOC的有效性。 展开更多
关键词 模块化多电平变流器 功率损耗优化控制 子模块故障 变执行频率
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Innovative Teaching Research on Literary Theory and Criticism
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作者 HOU Xia 《Sino-US English Teaching》 2024年第7期309-313,共5页
As a core compulsory course for English majors majoring in teacher education,Literary Theory and Criticism plays an important role in enhancing text understanding,cultivating critical thinking,and shaping correct valu... As a core compulsory course for English majors majoring in teacher education,Literary Theory and Criticism plays an important role in enhancing text understanding,cultivating critical thinking,and shaping correct values in the future development of students.Influenced by traditional teaching ideas,students have many difficulties when learning this course,such as insufficient theoretical understanding,inadequate ability improvement,and not enough investment in course learning.In response to the above issues,this course focuses closely on the fundamental task of“cultivating virtue and nurturing people”,relying on modern information technology and introducing research methods of digital humanities.This course uses“7C”teaching mode under the“three-level integration”,in which“teaching”and“education”are carried out synchronously,and“teacher”and“student”are developed together,in order to greatly enhance students’learning participation and course satisfaction. 展开更多
关键词 literary theory and criticism double helix 7C teaching mode three-level integration participation rate satisfaction level
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模块化多电平变换器改进两段式模型预测控制
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作者 李天皓 姚磊 张帅龙 《电力自动化设备》 EI CSCD 北大核心 2024年第4期96-104,共9页
基于有限控制集的模型预测控制应用于模块化多电平变换器(MMC)时通常会暴露出计算复杂与交流侧输出电流严重失真等问题。提出一种双矢量优化谐波电流模型预测控制策略,即改进两段式模型预测控制,可减少开关状态组合计算量,进一步优化交... 基于有限控制集的模型预测控制应用于模块化多电平变换器(MMC)时通常会暴露出计算复杂与交流侧输出电流严重失真等问题。提出一种双矢量优化谐波电流模型预测控制策略,即改进两段式模型预测控制,可减少开关状态组合计算量,进一步优化交流侧输出电流。推导了MMC离散数学模型,并构建无权重因子的代价函数,通过计算实际电流与参考电流包围的最小面积重新定义同一周期内两阶段开关信号的占空比,并引入一种附加冗余子模块的方法抑制桥臂环流,接着提出一种败者树多路归并排序算法均衡电容电压。在MATLAB/Simulink平台搭建三相23电平MMC仿真模型验证该策略的有效性。相比于两段式模型预测控制,所提策略的交流侧输出电流跟踪更加精准,谐波畸变率更小。 展开更多
关键词 模块化多电平变换器 改进两段式模型预测控制 附加冗余子模块 电容电压均衡 总谐波畸变率
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具备直流短路故障阻断能力的子模块桥臂复用型模块化多电平固态变压器
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作者 鄢寅宇 孙毅超 +1 位作者 郭宛鑫 侯凯 《电网技术》 EI CSCD 北大核心 2024年第3期1224-1234,共11页
模块化多电平换流器的固态变压器(modular multilevel converter based solid state transformer,MMC-SST)由于具备多电压等级、多电压形态的端口,在交直流混合配电网中得到广泛关注。传统的输入串联输出并联(inputseriesoutput paralle... 模块化多电平换流器的固态变压器(modular multilevel converter based solid state transformer,MMC-SST)由于具备多电压等级、多电压形态的端口,在交直流混合配电网中得到广泛关注。传统的输入串联输出并联(inputseriesoutput parallel,ISOP)型MMC-SST具有较高的功率密度,但是在中压直流(medium voltage DC,MVDC)端口短路故障情况下无法持续向低压侧供电;双向有源全桥变换器(dualactive bridge,DAB)型MMC-SST则存在功率密度低、成本高等问题,并且传统的半桥结构的DAB型MMC-SST在MVDC端口短路故障情况下同样无法持续向低压侧供电。文章提出了一种子模块桥臂复用(arm integrated submodule,AISM)型MMC-SST拓扑,在不改变MMC-SST端口电气特性的情况下,在有效减少开关器件数量的同时,还使得SST具备中压直流端口短路故障下的不间断运行能力,进而提升SST的功率密度和供电可靠性。针对文中提出的AISM型MMCSST拓扑,该文还提出了一种针对输入级MMC的混频调制方法,基于共模、差模解耦原理,实现输入级MMC桥臂电压的高频分量和低频分量的解耦。通过理论分析与仿真模拟,验证了所提拓扑及控制方法的可行性。 展开更多
关键词 模块化多电平固态变压器 子模块桥臂复用 中压直流短路故障不间断运行 混频调制
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模块化多电平换流器子模块故障分析与诊断方法综述
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作者 刘毅冲 《电工技术》 2024年第5期8-13,19,共7页
随着模块化多电平换流器(Modular Multilevel Converter,MMC)的广泛应用,其内部存在的问题也日益突出并成为制约系统稳定运行的主要因素。MMC子模块拓扑结构分为半H桥型、全H桥型和双箝位型3种,其中最典型的是半H桥型子模块,其内部由2个... 随着模块化多电平换流器(Modular Multilevel Converter,MMC)的广泛应用,其内部存在的问题也日益突出并成为制约系统稳定运行的主要因素。MMC子模块拓扑结构分为半H桥型、全H桥型和双箝位型3种,其中最典型的是半H桥型子模块,其内部由2个IGBT以及与其反并联的二极管和1个电容组成。在运行平稳的电路中,若子模块内部二极管、IGBT、储能电容任一发生故障,都可能会引起系统内部电路结构的变化,致使系统无法稳定运行,甚至直接崩溃。因此,对子模块内部故障的研究很有意义。针对IGBT、二极管和电容在子模块中的故障情况以及故障诊断与定位的方法进行了详细的介绍与分析。 展开更多
关键词 模块化多电平换流器(MMC) 子模块 故障分析 故障诊断与定位
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Generation of the nonlocal quantum entanglement of three three-level particles by local operations 被引量:2
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作者 金星日 张英俏 +1 位作者 金哲 张寿 《Chinese Physics B》 SCIE EI CAS CSCD 2005年第10期1936-1941,共6页
We propose a scheme to realize the nonlocal quantum entanglement of three three-level particles by using a threeparticle entangled state of three levels as a quantum channel with the aid of some local unitary transfor... We propose a scheme to realize the nonlocal quantum entanglement of three three-level particles by using a threeparticle entangled state of three levels as a quantum channel with the aid of some local unitary transformations. This scheme can be directly generalized to the nonlocal quantum entanglement of N three-level particles. 展开更多
关键词 quantum entanglement three-level particle unitary transformation
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A scheme for conditional quantum phase gate via bimodal cavity and a∧-type three-level atom 被引量:3
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作者 蔡建武 方卯发 +1 位作者 廖湘平 郑小娟 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第11期2518-2522,共5页
We propose a scheme to implement a two-qubit conditional quantum phase gate for the intracavity field via a single three-level ∧-type atom driven by two modes in a high-Q cavity. The quantum inforraation is encoded o... We propose a scheme to implement a two-qubit conditional quantum phase gate for the intracavity field via a single three-level ∧-type atom driven by two modes in a high-Q cavity. The quantum inforraation is encoded on the Fock states of the bimodal cavity. The gate's averaged fidelity is expected to reach 99.8%. 展开更多
关键词 quantum phase gate ∧-type three-level atom bimodal cavity FIDELITY
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Suppression of Phase and Amplitude Damping Decoherence in a Three-Level Atom in A-Configuration Using Bang-Bang Controls 被引量:1
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作者 WANG Yan-Hui LIU Xiao-Shu LONG Gui-Lu1 Key Laboratory for Atomic and Molecular NanoSciences and Department of Physics,Tsinghua University,Beijing 100084,China2 Tsinghua National Laboratory for Information Science and Technology,Tsinghua University,Beijing 100084,China 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第7期71-74,共4页
In this paper,we present decoupling bang-bang operations for the suppression of general decoherence,bothamplitude and phase damping,in a three-level system in A-configuration.We give a program to design a sequence ofp... In this paper,we present decoupling bang-bang operations for the suppression of general decoherence,bothamplitude and phase damping,in a three-level system in A-configuration.We give a program to design a sequence ofperiodic twinborn pulses to suppress the decoherence in such the system. 展开更多
关键词 bang-bang operation general decoherence three-level system
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Entropy squeezing for a V-type three-level atom interacting with a single-mode field and passing through the amplitude damping channel with weak measurement 被引量:1
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作者 张翠玉 方卯发 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第1期158-163,共6页
The entropy squeezing of a V-type three-level atom interacting with a single-mode field and passing through the amplitude damping channel is investigated in detail. Our results show that when coupled to the single-mod... The entropy squeezing of a V-type three-level atom interacting with a single-mode field and passing through the amplitude damping channel is investigated in detail. Our results show that when coupled to the single-mode field, the atom in appropriate initial states can not only generate obvious entropy squeezing but also keep in the optimal squeezing state,while passing through the amplitude damping channel, the atom can generate entropy squeezing under the control of the weak measurement. Besides, it is proved again that as a measurement method for atomic squeezing, the entropy squeezing is precise and effective. Therefore our work is instructive for experiments in preparing three-level system information resource with ultra-low quantum noise. 展开更多
关键词 entropy squeezing V-type three-level atom single-mode field weak measurement
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Radiation forces on a three-level atom in the high-order Bessel beams 被引量:1
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作者 王正岭 印建平 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第7期2466-2477,共12页
The general expressions of the average dissipative and dipole forces acting on a A-configuration three-level atom in an arbitrary light field are derived by means of the optical Bloch equations based on the atomic den... The general expressions of the average dissipative and dipole forces acting on a A-configuration three-level atom in an arbitrary light field are derived by means of the optical Bloch equations based on the atomic density matrix elements, and the general properties of the average dissipative and dipole forces on a three-level atom in the linearly-polarized high-order Bessel beams (HBBs) are analysed. We find a resonant property (with two resonant peaks) of the dissipative force and a non-resonant property (with two pairs of non-resonant peaks) of the dipole force on the three-level atom, which are completely different from those on the two-level atom. Meanwhile we find a saturation effect of the average dissipative force in the HBB, which comes from the saturation of the upper-level population. Our study shows that the general expressions of the average dissipative and dipole forces on the three-level atom will be simplified to those of the two-level atom under the approximation of large detuning. Finally, we study the axial and azimuthal Doppler cooling of atoms in ID optical molasses composed of two counter-propagating HBBs and discuss the azimuthal influence of the HBB on the Doppler cooling limit. We also find that the Doppler limit of atoms in the molasses HBB is slightly below the conventional Doppler limit of hГ/(2kB) due to the orbital angular momentum lh of the HBB. 展开更多
关键词 radiation forces optical Bloch equations three-level atom azimuthal Doppler cooling
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