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Violation of the T^(−1) Relationship in the Lattice Thermal Conductivity of Mg_(3)Sb_(2) with locally Asymmetric Vibrations

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Research 2020年第1期2020卷 750-759页

作者： Yifan Zhu Yi Xia Yancheng Wang Ye Sheng Jiong Yang Chenguang Fu Airan Li Tiejun Zhu Jun Luo Christopher Wolverton GJeffrey Snyder Jianjun Liu Wenqing Zhang State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Materials Genome Institute Shanghai UniversityShanghai 200444China Department of Materials Science and Engineering Northwestern UniversityIL 60208USA Max Planck Institute for Chemical Physics of Solids Dresden 01187Germany State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Department of Physics and Shenzhen Institute for Quantum Science&Engineering Southern University of Science and TechnologyShenzhen 518055China Guangdong Provincial Key Lab for Computational Science and Materials Design and Shenzhen Municipal Key Lab for Advanced Quantum Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

Most crystalline materials follow the guidelines of T^(-1) temperature-dependent lattice thermal conductivity(κ_(L))at elevated temperatures.Here,we observe a weak temperature dependence ofκL in Mg_(3)Sb_(2),T^(-0:48) from theory and T-0:57 from measurements,based on a comprehensive study combining ab initio molecular dynamics calculations and experimental measurements on single crystal Mg_(3)Sb_(2).These results can be understood in terms of the so-called“phonon renormalization”effects due to the strong temperature dependence of the interatomic force constants(IFCs).The increasing temperature leads to the frequency upshifting for those low-frequency phonons dominating heat transport,and more importantly,the phononphonon interactions are weakened.In-depth analysis reveals that the phenomenon is closely related to the temperature-induced asymmetric movements of Mg atoms within MgSb_(4) tetrahedron.With increasing temperature,these Mg atoms tend to locate at the areas with relatively low force in the force profile,leading to reduced effective 3^(rd)-order IFCs.The locally asymmetrical atomic movements at elevated temperatures can be further treated as an indicator of temperature-induced variations of IFCs and thus relatively strong phonon renormalization.The present work sheds light on the fundamental origins of anomalous temperature dependence of κ_(L) in thermoelectrics.

关键词： phonon Conductivity locally

locally Linear Back-propagation Based Contribution for Nonlinear Process Fault Diagnosis

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 764-775页

作者： Jinchuan Qian Li Jiang Zhihuan Song State Key Laboratory of Industrial Control Technology College of Control Science and EngineeringZhejiang UniversityHangzhou 310027China Shanghai Research Institute of Huawei Technology Co. LtdShanghai 200127China

This paper proposes a novel locally linear backpropagation based contribution(LLBBC) for nonlinear process fault diagnosis. As a method based on the deep learning model of auto-encoder(AE), LLBBC can deal with the fault diagnosis problem through extracting nonlinear features. When the on-line fault diagnosis task is in progress, a locally linear model is firstly built at the current fault sample. According to the basic idea of reconstruction based contribution(RBC), the propagation of fault information is described by using back-propagation(BP) algorithm. Then, a contribution index is established to measure the correlation between the variable and the fault, and the final diagnosis result is obtained by searching variables with large contributions. The smearing effect, which is an important factor affecting the performance of fault diagnosis, can be suppressed as well,and the theoretical analysis reveals that the correct diagnosis can be guaranteed by LLBBC. Finally, the feasibility and effectiveness of the proposed method are verified through a nonlinear numerical example and the Tennessee Eastman benchmark process.

关键词： Auto-encoder(AE) deep learning fault diagnosis locally linear model nonlinear process reconstruction based contribution(RBC)

locally Resonant Gaps of Phononic Beams Induced by Periodic Arrays of Resonant Shunts

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Chinese Physics Letters 2011年第9期28卷 166-169页

作者：陈圣兵温激鸿王刚韩小云温熙森 Laboratory of Science and Technology on Integrated Logistics Support National University of Defense TechnologyChangsha 410073

Periodic arrays of shunted piezoelectric patches are employed to control the propagation of elastic waves in phononic beams.Each piezo-patch is connected to a single resistance-inductance-capacitance shunting circuit.Therefore,the resonances of the shunting circuits will produce locally resonant gaps in the phononic beam.However,the existence of locally resonant gaps induced by resonant shunts has not been clearly proved by experiment so far.In this work,the locally resonant gap in a piezo-shunted phononic beam is investigated theoretically and verified by experiment.The results prove that resonances of shunting circuits can produce locally resonant gaps in phononic beams.

关键词： experiment resonant locally

Broadband Acoustic Transmission Enhancement through a Structured Stiff Plate with locally Resonant Elements

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Chinese Physics Letters 2012年第11期29卷 123-126页

作者：李勇梁彬邹欣晔程建春 Key Laboratory of Modern Acoustics MOEInstitute of AcousticsDepartment of PhysicsNanjing UniversityNanjing 210093 State Key Laboratory of Acoustics Chinese Academy of SciencesBeijing 100190

Broadband acoustic transmission enhancement(ATE)is realized for a periodically structured stiff plate without any opening that is conventionally thought to be only capable of supporting narrowband ATE,by introducing locally resonant(LR)elements.This exotic phenomenon is interpreted by analyzing the vibration pattern of the structure-induced LR modes,and is well modeled by a simple"spring-mass"system which reveals the contribution of the LR effect to the important broadband performance.Our findings should help to better understand the physical mechanism of ATE and may have potential impact on ultrasonic applications such as broadband acoustic filters or compact acoustic devices in subwavelength scale.

关键词： locally resonant stiff

locally risk-minimizing strategies in discrete time incomplete financial markets

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Chinese Science Bulletin 1998年第19期43卷 1601-1604页

作者： Shengwu He Jianming Xia E China Normal Univ Dept Stat Shanghai 200062 Peoples R China

For discrete time case a characterization of locally risk-minimizing strategies is given. Based on this characterization, it is evident that risk-minimizing strategies must be locally risk-minimizing.

关键词： mathematical finance incomplete financial market locally risk-minimizing strategy.

Deformation in locally convex topological linear spaces

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Science China Mathematics 2004年第5期47卷 687-710页

作者： DING Yanheng Institute of Mathematics Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100080 China

We are concerned with a deformation theory in locally convex topological linear spaces. A special 'nice' partition of unity is given. This enables us to construct certain vector fields which are locally Lipschitz continuous with respect to the locally convex topology. The existence, uniqueness and continuous dependence of flows associated to the vector fields are established. Deformations related to strongly indefinite functionals are then obtained. Finally, as applications, we prove some abstract critical point theorems.

关键词： locally convex topology, deformation, critical point.

The Existence of Simultaneous Bragg and locally Resonant Band Gaps in Composite Phononic Crystal

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Chinese Physics Letters 2013年第4期30卷 110-114页

作者：徐艳龙陈常青田晓耕 State Key Laboratory for Mechanical Structure Strength and Vibration Xi'an Jiaotong UniversityXi'an 710049 Department of Engineering Mechanics AML&CNMMTsinghua UniversityBeijing 100084

The band structure and transmission coefficient of the two-dimensional ternary locally resonant phononic crystal are computed by the finite element method with the calculated frequency up to 120 kHz.The band gap in the high frequency range is found and considered as the Bragg band gap in the locally resonant phononic crystal which has the locally resonant band gap in the low frequency range normally.Then,a composite phononic crystal by hybridizing the Bragg scattering phononic crystal and the locally resonant phononic crystal is proposed.Simultaneous Bragg and locally resonant band gaps are displayed and discussed for the composite phononic crystal.The results show that the simultaneous Bragg band gap and locally resonant band gap can be tuned.

关键词： resonant locally crystal

Strong uniform convergence of composition sequences of probability measures on locally compact topological semigroups

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Science China Mathematics 1997年第1期40卷 37-44页

作者：刘锦萼 Department of Statistics Shandong Institute of Economics Jinan 250014 China

Weak convergence of convolution products of non-identical probability measures on topological semigroups is investigated Firstly, the dependence relationship between the semigroup N of measures and suppN is studied; secondly, a necessary and sufficient condition that insures the strong uniform composition convergence of sequence |μn| is presented; thirdly, a more extensive class of semigroups is found, on which |μn| must be of strong uniform composition convergence, if it is of composition convergence.

关键词： locally compact semigroup probability measure composition convergence.

Decrease in the Ki67 index during neoadjuvant chemotherapy predicts favorable relapse-free survival in patients with locally advanced breast cancer

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Cancer Biology & Medicine 2019年第3期16卷 575-586页

作者： Chunfa Chen Yuling Zhang Ziyi Huang Jundong Wu Wenhe Huang Guojun Zhang Department of Thyroid and Breast Surgery The First Affiliated Hospital of Shantou University Medical CollegeShantou515041China Department of Information The Breast Center Cancer Hospital of Shantou University Medical CollegeShantou515031China Cancer Center Xiang'an Hospital of Xiamen UniversitySchool of MedicineXiamen UniversityXiamen361100China Changjiang Scholar’s Laboratory Cancer Hospital of Shantou University Medical CollegeShantou515031China

Objective: The purpose of this study was to explore the optimal cutoffs of the three parameters of Ki67 during NAC for predicting patient prognosis and investigate whether the optimal cutoffs of the Ki67 values were associated with relapse-free survival(RFS) or breast cancer-specific survival(BCSS).Methods: A total of 92 patients with locally advanced breast cancer(LABC), who had residual disease after NAC were retrospectively investigated.The optimal cutoff values of the Ki67 parameters were assessed by the online algorithm Cutoff Finder.Kaplan-Meier analysis, the log-rank test and Cox regression analysis were carried out to analyze survival.Results: The optimal cutoff values for the postsurgical Ki67 level and the decrease in the Ki67 level during NAC were defined as 25% and 12.5%, respectively.According to the univariate survival analysis, a higher Ki67 level in residual disease was associated with poor RFS(P = 0.004) and BCSS(P = 0.014).In addition, a Ki67 expression decrease > 12.5% during NAC was related to favorable RFS(P = 0.007), but was not related to BCSS(P = 0.452).Cox regression analysis showed that the Ki67 expression decrease(> 12.5% vs.≤ 12.5%) and histological grade(grade 3 vs.grade 1-2) were the independent factors associated with RFS(P =0.020 and P = 0.023, respectively), with HR values of 0.353(95% CI: 0.147-0.850) and 3.422(95% CI: 1.188-9.858), respectively.Conclusions: The Ki67 decrease was one of the independent factors associated with RFS in LABC patients with residual disease after receiving NAC.

关键词： Ki67 locally advanced breast cancer neoadjuvant chemotherapy prognosis residual disease