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Stokes'first problem for the fourth order fluid in a porous half space 被引量:4
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作者 T.Hayat F.Shahazad M.Ayub 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第1期17-21,共5页
In this study, the flow of a fourth order fluid in a porous half space is modeled. By using the modified Darcy's law, the flow over a suddenly moving flat plate is studied numerically. The influence of various parame... In this study, the flow of a fourth order fluid in a porous half space is modeled. By using the modified Darcy's law, the flow over a suddenly moving flat plate is studied numerically. The influence of various parameters of interest on the velocity profile is revealed. 展开更多
关键词 Fourth order fluid Porous space Numerical solution Modified Darcy's law
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[WS_(3)Cu_(2)]簇基超分子框的组装、结构及其三阶非线性光学响应
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作者 余蕙敏 王志康 +3 位作者 李洁 宋瑛林 杜明浩 郎建平 《无机化学学报》 SCIE CSCD 北大核心 2024年第1期71-78,共8页
将二(4-吡啶)硫烷(L_(1))、4,4'-二(4-吡啶)二苯甲酮(L_(2))分别与(Et_(4)N)(Tp*WS_(3))(A)(Tp*=三(3,5-二甲基吡唑)氢合硼酸根)和[Cu(Me CN)_(4)]PF_(6)进行反应,得到2个W/Cu/S簇基超分子化合物[Tp*WS_(3)Cu_(2)(L_(1))]_(2)(PF_(6... 将二(4-吡啶)硫烷(L_(1))、4,4'-二(4-吡啶)二苯甲酮(L_(2))分别与(Et_(4)N)(Tp*WS_(3))(A)(Tp*=三(3,5-二甲基吡唑)氢合硼酸根)和[Cu(Me CN)_(4)]PF_(6)进行反应,得到2个W/Cu/S簇基超分子化合物[Tp*WS_(3)Cu_(2)(L_(1))]_(2)(PF_(6))_(2)·2Me CN·2CHCl_(3)(1·2Me CN·2CHCl_(3))和[Tp*WS_(3)Cu_(2)(L_(2))(Me CN)]_(2)(PF_(6))_(2)·4Me CN (2·4Me CN)。对配合物1·2Me CN·2CHCl_(3)和2·4Me CN分别进行了单晶X射线衍射、核磁、质谱、红外、紫外可见和元素分析表征。单晶X射线衍射分析表明,它们是由2个L_(1)/L_(2)配体连接2个[Tp*WS_(3)Cu_(2)]~+簇核形成的阳离子型簇基超分子框。核磁氢谱和高分辨电喷雾离子化质谱(HRESI-MS)证明它们在溶液中具有一定的稳定性。并利用Z扫描技术测试了超分子化合物1·2Me CN·2CHCl_(3)和2·4MeCN溶液的三阶非线性光学特性,测试结果表明它们的三阶非线性光学响应强于前驱体A。 展开更多
关键词 W/Cu/s 超分子框 三阶非线性光学性质
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Unifying the theory of integration within normal-,Weyl- and antinormal-ordering of operators and the s-ordered operator expansion formula of density operators 被引量:2
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作者 范洪义 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第5期41-47,共7页
By introducing the s-parameterized generalized Wigner operator into phase-space quantum mechanics we invent the technique of integration within s-ordered product of operators (which considers normally ordered, antino... By introducing the s-parameterized generalized Wigner operator into phase-space quantum mechanics we invent the technique of integration within s-ordered product of operators (which considers normally ordered, antinormally ordered and Weyl ordered product of operators as its special cases). The s-ordered operator expansion (denoted by s…s ) formula of density operators is derived, which isρ=2/1-s∫d^2β/π〈-β|ρ|β〉sexp{2/s-1(s|β|^2-β*α+βa-αα)}s The s-parameterized quantization scheme is thus completely established. 展开更多
关键词 s-parameterized generalized Wigner operator technique of integration within s-ordered product of operators s-ordered operator expansion formula s-parameterized quantization scheme
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The Transition of the international Order and China's Role
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作者 Wang Honggang 《Contemporary International Relations》 2017年第1期1-28,共28页
The international order is built on the principles of sovereign equality,national interests,great powers and respect for human rights among others.International rivalry and cooperation have existed side by side over t... The international order is built on the principles of sovereign equality,national interests,great powers and respect for human rights among others.International rivalry and cooperation have existed side by side over the past few centuries,while the foundations of an international order have solidified.We are now seeing a transition in the international order that requires new innovative ways of thinking.China is seen as the key driver of these changes because of its unique status,pattern of growth and future potential.China should embrace this historic opportunity and take on its obligations to contribute to the birth of a new modern international order. 展开更多
关键词 Modern international order EVOLUTION China’s great rejuvenation responsibility of the times
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THE EXACT ORDER OF |x-x_k|~s|I_k(x)|~t
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作者 史应光 《Analysis in Theory and Applications》 1992年第3期1-10,共10页
In this paper we give the exact order of丨x-x_k丨~丨l_k(x)丨~for any fixed nonnegative integers s and t,which is n^(-s),n^(-s)lnn and n^(1-)for s≤t-2,s=t-1 and s≥t, respectively.
关键词 x-x_k the EXACT order OF s|I_k
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Georg Cantor’s Ordinals, Absolute Infinity&Transparent Proof of the Well-Ordering Theorem Cantor’s 1899 Letter to Dedekind
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作者 Hermann G.W.Burchard 《Journal of Philosophy Study》 2019年第8期435-444,共10页
Georg Cantor’s absolute infinity, the paradoxical class Ω of all ordinals, a non-entity for which being called a “class” is an undeserved dignity, must be the ultimate vexation for mathematical philosophers who ho... Georg Cantor’s absolute infinity, the paradoxical class Ω of all ordinals, a non-entity for which being called a “class” is an undeserved dignity, must be the ultimate vexation for mathematical philosophers who hold on to some residual realism in set theory. By careful use of Ω, we can rescue Georg Cantor’s 1899 “proof” sketch of the Well-Ordering Theorem (being generous, considering his declining health) by taking the contrapositive of his suggestion and adding Zermelo’s choice function, resulting in a concise and uncomplicated proof of the Well-Ordering Theorem. 展开更多
关键词 WELL orderING theOREM Burali-Forti’s PARADOX Kant’s Oneness Function
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基于分数阶S面模型的四旋翼轨迹跟踪控制
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作者 李佳成 陈鹏云 常哲 《兵器装备工程学报》 CAS CSCD 北大核心 2024年第3期286-292,共7页
四旋翼无人机具有欠驱动、非线性、强耦合的特点。针对四旋翼无人机轨迹跟踪控制中跟踪精度低,抗外界干扰能力弱的特点,通过对四旋翼无人机进行四元数建模,使用误差四元数作为控制器输入,消除了无人机在机动角度过大时的奇点问题,提出... 四旋翼无人机具有欠驱动、非线性、强耦合的特点。针对四旋翼无人机轨迹跟踪控制中跟踪精度低,抗外界干扰能力弱的特点,通过对四旋翼无人机进行四元数建模,使用误差四元数作为控制器输入,消除了无人机在机动角度过大时的奇点问题,提出了一种分数阶S面的控制方法,即将分数阶PID控制与S面控制融合,作为一个新的控制器。轨迹跟踪试验表明,分数阶S面控制器在四旋翼无人机控制模型中的累计误差明显小于分数阶PID,证明了该方法具有抗风扰能力强、跟踪精度高的特点。 展开更多
关键词 四旋翼无人机 四元数 分数阶PID s面控制 轨迹跟踪
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Deriving some quantum optical identities using the general ordering theorem
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作者 Farid Shhandeh Mohammad Reza Bazrafkan Elahe Nahvifard 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第11期233-236,共4页
Using the newly introduced general ordering theorem by Sh/ihandeh and Bazrafkan, we derive and generalize some quantum optical identities and give their applications.
关键词 s-ordered expansion of operators general ordering theorem
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基于n阶S形曲线的SCARA多目标运动规划
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作者 吴坤 王明威 周康 《组合机床与自动化加工技术》 北大核心 2024年第1期14-18,24,共6页
为了对SCARA机器人运动过程中产生的振动进行有效抑制,首先,建立了SCARA机器人的简化浮动坐标法动力学模型;然后,利用n阶S形曲线构造了同时对定位时间和SCARA机器人受到的冲击进行优化的多目标优化模型;最后,采用基于Kriging模型的NSGA... 为了对SCARA机器人运动过程中产生的振动进行有效抑制,首先,建立了SCARA机器人的简化浮动坐标法动力学模型;然后,利用n阶S形曲线构造了同时对定位时间和SCARA机器人受到的冲击进行优化的多目标优化模型;最后,采用基于Kriging模型的NSGA-Ⅱ算法对优化问题进行求解。得到的多目标优化问题的Pareto前沿表明,四阶S形曲线的定位时间与三阶S形曲线大致相当,但是引起的冲击远小于三阶S形曲线。对优化结果的仿真也表明,以四阶S形曲线驱动的SCARA机器人运行过程更平滑,产生的残余振动也远小于三阶S形曲线。研究表明,四阶S形曲线具备比三阶S形曲线更加优良的振动抑制性能,在工程中具有广泛的应用价值。 展开更多
关键词 机械电子工程 sCARA机器人 振动抑制 运动规划 n阶s形曲线
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Order of China's Major Banks among the World's 1000 Banks
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《China's Foreign Trade》 1998年第11期35-35,共1页
19981997BankNameCapitalTotalassetsCapitalPretaxprofitAverageCapitalAssetsasetrateprofitratereturns2225Indust... 19981997BankNameCapitalTotalassetsCapitalPretaxprofitAverageCapitalAssetsasetrateprofitratereturns2225Industrial&Comm115.9343... 展开更多
关键词 World’s the AMONG MAJOR order BANKs China’s
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Operators's-parameterized ordering and its classical correspondence in quantum optics theory
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作者 范洪义 袁洪春 胡利云 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第10期289-295,共7页
In reference to the Weyl ordering xmpn→ (1/2)m ∑l=0m (ml)Xm-lPnXl , where X and P are coordinate and momentum operator, respectively, this paper examines operators' s-parameterized ordering and its classical co... In reference to the Weyl ordering xmpn→ (1/2)m ∑l=0m (ml)Xm-lPnXl , where X and P are coordinate and momentum operator, respectively, this paper examines operators' s-parameterized ordering and its classical correspondence, finds the fundamental function-operator correspondence (1-s/2)(n+m)/2Hm,n(/2/1-sα,/2/1-sα)→αman and its complementary relation anam→(-i)n+m(1-s/2)(m+n)/2:Hm,n(i√2/1-sa,i√2/1-sa),where Hrn,n is the two-variable Hermite polynomial, a, at are bosonic annihilation and creation operators respectively, s is a complex parameter. The s'-ordered operator power-series expansion of s-ordered operator atraan in terms of the two-variable Hermite polynomial is also derived. Application of operators' s-ordering formula in studying displaced- squeezed chaotic field is discussed. 展开更多
关键词 s-ordered operator expansion formula the IWsOP technique two-variable Hermite polynomial
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基于高阶多道同步挤压广义S变换的多属性融合储层预测技术研究及应用
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作者 赵慧言 高欢 +2 位作者 严海滔 文冉 宋修艳 《海相油气地质》 CSCD 北大核心 2024年第2期207-214,共8页
时频域地震精细解释建立在高分辨率时频分析算法的基础上。为适应高精度勘探开发的要求,在多道同步挤压广义S变换(MSGST)的基础上,提出了高阶多道同步挤压广义S变换(HMSGST),进一步聚焦时频分辨率,提高储层预测的精准性。通过理论信号... 时频域地震精细解释建立在高分辨率时频分析算法的基础上。为适应高精度勘探开发的要求,在多道同步挤压广义S变换(MSGST)的基础上,提出了高阶多道同步挤压广义S变换(HMSGST),进一步聚焦时频分辨率,提高储层预测的精准性。通过理论信号、理论加噪信号对比6种时频算法的计算结果,验证了HMSGST具有高时频分辨率,对复杂信号具有更好的刻画能力。以某三维工区海相砂岩为例,基于HMSGST在时频域沿主要油气储层(T2层)提取时间切片,开展频率衰减梯度、分频相干等属性分析以增强对短轴河道、次级断裂等目标的识别能力和烃类检测能力,进一步结合曲率属性开展RGB多属性融合精细雕刻。对于不同工区、不同地质条件的地震数据,需要进行HMSGST的参数分析,适合的参数是达到更为准确的计算结果的前提。 展开更多
关键词 时频分析 高阶多道同步挤压广义s变换 时频分辨率 多属性融合 储层预测
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On the Women Image in The Woman Warrior — Based on the Theory of Lacan's Symbolic Order
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作者 桂花 《海外英语》 2016年第1期166-167,共2页
According to the theory of Lacan's symbolic order, gender identity is determined by the culture that people live in.The culture is the chief determinant of women's gender and their destiny. The Woman Warrior i... According to the theory of Lacan's symbolic order, gender identity is determined by the culture that people live in.The culture is the chief determinant of women's gender and their destiny. The Woman Warrior is the autobiographical novel of Maxine Hong Kingston, in which there are different women images who live in different cultures. The this paper focuses on analyzing the tragic fate of"no name woman"who lives in traditional Chinese patriarchy culture and the hard experience of"I"who struggles between Chinese patriarchy culture and American feminism culture. 展开更多
关键词 the theory of Lacan’s sYMBOLIC order Chinese PATRIARCHY CULTURE FEMINIsM CULTURE the WOMAN WARRIOR W
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On the Cosmic Evolution of the Quantum Vacuum Using Two Variable G Models and Winterberg’s Thesis
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作者 Christopher Pilot 《Journal of High Energy Physics, Gravitation and Cosmology》 2023年第4期1134-1160,共27页
We work within a Winterberg framework where space, i.e., the vacuum, consists of a two component superfluid/super-solid made up of a vast assembly (sea) of positive and negative mass Planck particles, called planckion... We work within a Winterberg framework where space, i.e., the vacuum, consists of a two component superfluid/super-solid made up of a vast assembly (sea) of positive and negative mass Planck particles, called planckions. These material particles interact indirectly, and have very strong restoring forces keeping them a finite distance apart from each other within their respective species. Because of their mass compensating effect, the vacuum appears massless, charge-less, without pressure, net energy density or entropy. In addition, we consider two varying G models, where G, is Newton’s constant, and G<sup>-1</sup>, increases with an increase in cosmological time. We argue that there are at least two competing models for the quantum vacuum within such a framework. The first follows a strict extension of Winterberg’s model. This leads to nonsensible results, if G increases, going back in cosmological time, as the length scale inherent in such a model will not scale properly. The second model introduces a different length scale, which does scale properly, but keeps the mass of the Planck particle as, ± the Planck mass. Moreover we establish a connection between ordinary matter, dark matter, and dark energy, where all three mass densities within the Friedman equation must be interpreted as residual vacuum energies, which only surface, once aggregate matter has formed, at relatively low CMB temperatures. The symmetry of the vacuum will be shown to be broken, because of the different scaling laws, beginning with the formation of elementary particles. Much like waves on an ocean where positive and negative planckion mass densities effectively cancel each other out and form a zero vacuum energy density/zero vacuum pressure surface, these positive mass densities are very small perturbations (anomalies) about the mean. This greatly alleviates, i.e., minimizes the cosmological constant problem, a long standing problem associated with the vacuum. 展开更多
关键词 Winterberg Model Planck Particles Positive and Negative Mass Planck Particles Planckions Quantum Vacuum space as a superfluid/supersolid Extended Models for space Cosmological Constant Higgs Field as a Composite Particle Higgs Boson Inherent Length scale for the Vacuum Dark Energy Cosmological scaling Behavior for the Quantum Vacuum Variable G Models Extended Gravity Newton’s Constant as an order Parameter High Energy Behavior for the Vacuum
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The Bronze Acupuncture Model Produced by Emperor Qianlong’s Order in 1744 A.D.
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作者 Hong Qin 段英帅(译) 《Chinese Medicine and Culture》 2018年第1期21-24,共4页
The bronze acupuncture model was produced by Emperor Qianlong’s order in 1744 A.D.It has been 274 years since then,and this model has always been well kept and handed down with a full record.It is of great traditiona... The bronze acupuncture model was produced by Emperor Qianlong’s order in 1744 A.D.It has been 274 years since then,and this model has always been well kept and handed down with a full record.It is of great traditional medical and cultural value,regarded as the treasure of Shanghai Museum of Traditional Chinese Medicine due to its rareness and intactness both at home and abroad. 展开更多
关键词 Bronze acupuncture model Ding Jimin Fu Hai Wang Jimin Yi Zong Jin Jian(《医宗金鉴》Golden Mirror of Medicine) Yuzhi Zhenjiuxiang Chongxiuji(the Rebuilding Record of Acupuncture Models by Emperor’s order) Zhen sheng
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DOUBLE HIGH ORDER S-BREAKING BIFURCATION POINTS AND THEIR NUMERICAL DETERMINATION
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作者 杨忠华 叶瑞松 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1996年第7期633-646,共14页
We consider double high order S-breaking bifurcation points of two-Parameter dependent nonlinear problems with Z_2×Z_2-symmetry. Because of the underlying symmetry we could propose some regular extended systems... We consider double high order S-breaking bifurcation points of two-Parameter dependent nonlinear problems with Z_2×Z_2-symmetry. Because of the underlying symmetry we could propose some regular extended systems to determine double high order S-breaking bifurcation points. and we could also show that there exist two quadratic pitchfork bifurcation point paths passing through the point being considered. 展开更多
关键词 Z_2× Z_2-symmetry. double high order s-breaking bifurcation point. extended system
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不确定非方广义分数阶T-S模糊系统的鲁棒镇定
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作者 张雪峰 艾洁 赵泽丽 《控制理论与应用》 EI CAS CSCD 北大核心 2023年第1期47-54,共8页
针对不确定非方广义分数阶T-S模糊系统阶数为0<α<1的鲁棒镇定问题,提出了一个有效的判据.首先,利用一个新的T-S模糊动态补偿器,将不确定非方广义分数阶T-S模糊系统转化为一个增广的不确定方形广义分数阶T-S模糊系统.由于增广变... 针对不确定非方广义分数阶T-S模糊系统阶数为0<α<1的鲁棒镇定问题,提出了一个有效的判据.首先,利用一个新的T-S模糊动态补偿器,将不确定非方广义分数阶T-S模糊系统转化为一个增广的不确定方形广义分数阶T-S模糊系统.由于增广变量的引入,动态补偿器的设计问题可以等价为静态输出反馈控制器的设计问题.其次,设计一个分数阶导数反馈控制器对得到的增广系统进行正常化处理.然后,对正常化得到的不确定分数阶T-S模糊系统进行研究,得到一个系统渐近稳定的充分条件.该条件保守性小并且形式简洁.最后,通过一个数值算例和一个实际例子验证了本文所提出结论的正确性和有效性. 展开更多
关键词 非方广义分数阶系统 T-s模糊模型 动态补偿器 鲁棒镇定 线性矩阵不等式
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A Family of Fifth-order Iterative Methods for Solving Nonlinear Equations 被引量:4
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作者 Liu Tian-Bao Cai Hua Li Yong 《Communications in Mathematical Research》 CSCD 2013年第3期255-260,共6页
In this paper, we present and analyze a family of fifth-order iterative methods free from second derivative for solving nonlinear equations. It is established that the family of iterative methods has convergence order... In this paper, we present and analyze a family of fifth-order iterative methods free from second derivative for solving nonlinear equations. It is established that the family of iterative methods has convergence order five. Numerical examples show that the new methods are comparable with the well known existing methods and give better results in many aspects. 展开更多
关键词 Newton's method iterative method nonlinear equation order of convergence
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The N-mode squeezed state with enhanced squeezing 被引量:2
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作者 徐学翔 胡利云 范洪义 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第12期5139-5143,共5页
It is known that exp [iA (Q] P1 - i/2)] is a unitary single-mode squeezing operator, where Q1, P1 are the coordinate and momentum operators, respectively. In this paper we employ Dirac's coordinate representation t... It is known that exp [iA (Q] P1 - i/2)] is a unitary single-mode squeezing operator, where Q1, P1 are the coordinate and momentum operators, respectively. In this paper we employ Dirac's coordinate representation to prove that the exponential operator Sn ≡exp[iλi=1∑n(QiPi+1+Qi+1Pi))],(Qn+1=Q1,Pn+1=P1),is an n-mode squeezing operator which enhances the standard squeezing. By virtue of the technique of integration within an ordered product of operators we derive Sn's normally ordered expansion and obtain new n-mode squeezed vacuum states, its Wigner function is calculated by using the Weyl ordering invariance under similar transformations. 展开更多
关键词 Dirac's representation integration within an ordered product technique squeezing enhanced operator squeezed sate
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Three-dimensional ordered hierarchically porous carbon materials for high performance Li-Se battery 被引量:1
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作者 Hongyan Li Wenda Dong +9 位作者 Chao Li Tarek Barakat Minghui Sun Yingying Wang Liang Wu Lang Wang Lei Xia Zhi-Yi Hu Yu Li Bao-Lian Su 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第5期624-636,共13页
Developing host materials with high specific surface area, good electron conductivity, and fast ion transportation channel is critical for high performance lithium-selenium(Li-Se) batteries. Herein, a series of three ... Developing host materials with high specific surface area, good electron conductivity, and fast ion transportation channel is critical for high performance lithium-selenium(Li-Se) batteries. Herein, a series of three dimensional ordered hierarchically porous carbon(3D OHPC) materials with micro/meso/macropores are designed and synthesized for Li-Se battery. The porous structure is tuned by following the concept of the generalized Murray’s law to facilitate the mass diffusion and reduce ion transport resistance.The optimized 3D Se/OHPC cathode exhibits a very high 2 nd discharge capacity of 651 m Ah/g and retains 361 m Ah/g after 200 cycles at 0.2 C. Even at a high current rate of 5 C, the battery still shows a discharge capacity as high as 155 m Ah/g. The improved electrochemical performance is attributed to the synergy effect of the interconnected and well-designed micro, meso and macroporosity while shortened ions diffusion pathways of such Murray materials accelerate its ionic and electronic conductivities leading to the enhanced electrochemical reaction. The diffusivity coefficient in Se/OHPC can reach a very high value of 1.3 × 10^(-11)cm^(2)/s, much higher than those in single pore size carbon hosts. Their effective volume expansion accommodation capability and reduced dissolution of polyselenides ensure the high stability of the battery. This work, for the first time, established the clear relationship between textural properties of cathode materials and their performance and demonstrates that the concept of the generalized Murray’s law can be used as efficient guidance for the rational design and synthesis of advanced hierarchically porous materials and the great potential of 3D OHPC materials as a practical high performance cathode material for Li-Se batteries. 展开更多
关键词 3D ordered hierarchically porous carbon(OHPC) shuttle effect CYCLABILITY High rate capability the generalized Murray’s law Li-se batteries
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