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NS Condition of Admissibility for the Linear Estimator of Normal Mean with Unknown Variance

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Acta Mathematica Sinica,English Series 2005年第5期21卷 1083-1086页

作者： xing zhong xu Qi Guang WU Beijing Institute of Technology Beijing 100081 P. R. China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 P. R. China

Suppose Y - N（β, σ^2 In）, where β ∈ R^n and σ^2 〉 0 are unknown. We study the admissibility of linear estimators of mean vector under a quadratic loss function. A necessary and sufficient condition of the admi... 详细信息

关键词： Multivariate normal distribution Mean vector Linear estimator Admissibility

FDR Control for Pairwise Comparisons of Normal Means Based on Goodness of Fit Test

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Acta Mathematicae Applicatae Sinica 2016年第3期32卷 701-712页

作者： Pei JIN xing-zhong xu Na LI School of Mathematics and Statistics Beijing Institute of Technology School of Economics and Management University of the Chinese Academy of Sciences

This study is undertaken to apply a bootstrap method of controlling the false discovery rate （FDR） when performing pairwise comparisons of normal means. Due to the dependency of test statistics in pairwise comparisons, many conventional multiple testing procedures can＇t be employed directly. Some modified pro- cedures that control FDR with dependent test statistics are too conservative. In the paper, by bootstrap and goodness-of-fit methods, we produce independent p-values for pairwise comparisons. Based on these indepen- dent p-values, plenty of procedures can be used, and two typical FDR controlling procedures are applied here. An example is provided to illustrate the proposed approach. Extensive simulations show the satisfactory FDR control and power performance of our approach. In addition, the proposed approach can be easily extended to more than two normal, or non-normal, balance or unbalance cases.

关键词： multiple testing false discovery rate goodness-of-fit test pairwise comparisons p-value resampling

On the Unitriangular Groups over Rational Numbers Field

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Acta Mathematica Sinica,English Series 2022年第4期38卷 718-734页

作者： Rui GAO Jun LIAO He Guo LIU xing zhong xu School of Mathematics and Statistics Hubei UniversityWuhan 430062P.R.China

Let U(n,Q)be the group of all n×n(upper)unitriangular matrices over rational numbers field *** S be a subset of U(n,Q).In this paper,we prove that S is a subgroup of U(n,Q)if and only if the(i,j)-th entry S;satisfies some condition(see Theorem 3.5).Furthermore,we compute the upper central series and the lower central series for S,and obtain the condition that the upper central series and the lower central series of S coincide.

关键词： Nilpotent groups unitriangular groups central series

Finitely Generated Nilpotent Groups of Infinite Cyclic Commutator Subgroups

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Acta Mathematica Sinica,English Series 2020年第12期36卷 1315-1340页

作者： Jun LIAO He Guo LIU xing zhong xu Ji Ping ZHANG Hubei Key Laboratory of Applied Mathematics School of Mathematics and StatisticsHubei UniversityWuhan 430062P.R.China School of Mathematical Sciences Peking UniversityBeijing 100871P.R.China

The aim of this paper is to determine the structure and to establish the isomorphic invariant of the finitely generated nilpotent group G of infinite cyclic commutator *** the structure and invariant of the group which is the central extension of a cyclic group by a free abelian group offinite rank of infinite cyclic center,we provide a decomposition of G as the product of a generalized extraspecial Z-group and its *** using techniques of lifting isomorphisms of abelian groups and equivalent normal form of the generalized extraspecial Z-groups,we finally obtain the structure and invariants of the group G.

关键词： Nilpotent groups central extension isomorphic invariant

Nitrogen-doped titanium dioxide/schwertmannite nanocomposites as heterogeneous photo-Fenton catalysts with enhanced efficiency for the degradation of bisphenol A

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Journal of Environmental Sciences 2024年第9期143卷 1-11页

作者： xing-xing Qiao Yu-Hang xu Xiang-Ji Liu Sai-Le Chen Zhou zhong Ya-Feng Li Jian Lü Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China State Key Laboratory of Photocatalysis on Energy and Environment Fuzhou UniversityFuzhou 350116China

Potential health risks related to environmental endocrine disruptors(EEDs)have aroused research hotspots at the forefront of water treatment ***,nitrogen-doped titanium dioxide/schwertmannite nanocomposites(N-TiO_(2)/SCH)have been successfully developed as heterogeneous catalysts for the degradation of typical EEDs via photo-Fenton *** to the sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion induced by photoelectrons,as-prepared N-TiO_(2)/SCH nanocomposites exhibit much enhanced efficiency for the degradation of bisphenol A(BPA;ca.100% within 60 min under visible irradiation)in a wide pH range of 3.0-7.8,which is significantly higher than that of the pristine schwertmannite(ca.74.5%)or N-TiO_(2)(ca.10.8%).In this photo-Fenton system,the efficient degradation of BPA is mainly attributed to the oxidation by hydroxyl radical(·OH)and singlet oxygen(^(1)O_(2)).Moreover,the possible catalytic mechanisms and reaction pathway of BPA degradation are systematically investigated based on analytical and photoelectrochemical *** work not only provides a feasible means for the development of novel heterogeneous photo-Fenton catalysts,but also lays a theoretical foundation for the potential application of mineral-based materials in wastewater treatment.

关键词： Titanium dioxide Schwertmannite Fenton reaction Environmental endocrine disruptors Photocatalysis

Efficient recovery of tungsten from scheelite concentrates using a sulfur-phosphorus mixed acid leaching system

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Tungsten 2024年第4期6卷 821-832页

作者： Jiang-Tao Li Li-Li Gao zhong-Wei Zhao xu-Heng Liu xing-Yu Chen School of Metallurgy and Environment Central South University Key Laboratory of Hunan Province for Metallurgy and Material Processing of Rare Metals

In recent years,a new process for leaching scheelite concentrates with sulfur-phosphorus mixed acid has been successfully *** process suffers from the elimination of the retarding effect of calcium sulfate,the selective extraction of tungsten from the H3PW12O40-H2SO4-H3PO4mixture solution,and the removal of introduced ***,in this paper,we investigated the inhibition measures of a calcium sulfate-blocking membrane,the selective extraction of tungsten by ion exchange,and the removal of phosphorus by the magnesium ammonium salt *** results showed that the addition of calcium sulfate whisker seeds and a higher H3PO4concentration inhibited spontaneous diffuse nucleation,promoted crystal growth,and avoided the formation of a dense blocking *** 98 wt.% of the scheelite concentrate was digested by *** selective adsorption of PW12O403-was realized using D301 resin,and the extraction efficiency of tungsten exceeded 99.9%.After desorption with ammonia water,PW12O403-was depolymerized into WO42-and PO43-.99.9 wt.% of phosphorus was removed in the form of MgNH4PO4by the magnesium ammonium salt method,and the residual phosphorus concentration in the solution was lower than 10 mg·*** purification,the highest-grade ammonium paratungstate product was prepared by evaporative crystallization.

关键词： Calcium sulfate Ion exchange Scheelite concentrates Sulfur-phosphorus mixed acid Tungsten

Vision-based docking system for an aromatic-hydrocarbon-inspired reconfigurable robot

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Science China(Technological Sciences) 2024年第6期67卷 1798-1816页

作者： xing FangYi xu Cheng LIU JinGuo xuE ZhiHui State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang110016China School of Automation and Electrical Engineering Shenyang Ligong UniversityShenyang110158China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang110169China University of Chinese Academy of Sciences Beijing100049China

Aromatic hydrocarbons generally refer to compounds containing benzene *** types of isomers can be formed by replacing hydrogen atoms on the benzene *** this paper,an aromatic-hydrocarbon-inspired modular robot(AHIMR)is *** robot can be reassembled into different configurations suitable for various task requirements.A vision-based docking system is designed for the *** system primarily consists of two stages:a remote guidance stage and a precise docking *** the remote guidance stage,an object module is identified using an illumination adaptive target recognition algorithm,and then the active module moves to the docking area through communication with *** the precise docking stage,the active module calculates the relative pose with the object module using a perspective-n-point method and dynamically adjusts its posture to *** this process,a Kalman filter is used to reduce target occlusion and jitter *** addition,the docking system feasibility is verified via several simulation *** module docking accuracy is controlled within 0.01 m,which meets the reconfiguration task requirements of the *** the AHIMR submodule docking experiment,the active module accurately moves to the expected position with a docking success rate of 95%.

关键词： modular robot reconfiguration aromatic hydrocarbon autonomous docking visual identification

Design and simulation investigations on charge transport layers‑free in lead‑free three absorber layer all‑perovskite solar cells

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Frontiers of Optoelectronics 2024年第2期17卷 69-85页

作者： Guangdong Li Mingxiang xu zhong Chen School of Physics Southeast UniversityNanjing 211189China

The multiple absorber layer perovskite solar cells(PSCs)with charge transport layers-free(CTLs-free)have drawn widespread research interest due to their simplified architecture and promising photoelectric *** the circumstances,the novel design of CTLs-free inversion PSCs with stable and nontoxic three absorber layers(triple Cs_(3)Bi_(2)I_(9),single MASnI_(3),double Cs_(2)TiBr_(6))as optical-harvester has been numerically simulated by utilizing wxAMPS simulation software and achieved high power conversion efficiency(PCE)of 14.8834%.This is owing to the innovative architecture of PSCs favors efficient transport and extraction of more holes and the slender band gap MASnI_(3)extends the absorption spectrum to the near-infrared periphery compared with the two absorber layers architecture of ***,the performance of the device with p-type-Cs_(3)Bi_(2)I_(9)/p-type-MASnI_(3)/n-type-Cs_(2)TiBr_(6)architecture is superior to the one with the p-type-Cs_(3)Bi_(2)I_(9)/ntype-MASnI_(3)/n-type-Cs_(2)TiBr_(6)architecture due to less carrier recombination and higher carrier life time inside the absorber *** simulation results reveal that Cs_(2)TiF_(6)double perovskite material stands out as the best ***,an excellent PCE of 21.4530%can be obtained with the thicker MASnI_(3)absorber layer thickness(0.4μm).Lastly,the highestperformance photovoltaic devices(28.6193%)can be created with the optimized perovskite doping density of around E15 cm^(3)(Cs_(3)Bi_(2)I_(9)),E18 cm^(3)(MASnI_(3)),and 1.5E19 cm^(3)(Cs_(2)TiBr_(6)).This work manifests that the proposed CTLs-free PSCs with multi-absorber layers shall be a relevant reference for forward applications in electro-optical and optoelectronic devices.

关键词： Multiple absorber layer PSCs CTLS-free·Inverted Narrow-band gap Simulation

Ultrahigh thermoelectric properties of p‐type Bi_(x)Sb_(2−x)Te_(3)thin films with exceptional flexibility for wearable energy harvesting

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Carbon Energy 2024年第8期6卷 273-284页

作者： Zhuang‐Hao Zheng Yi‐Ming zhong Yi‐Liu Li Mohammad Nisar Adil Mansoor Fu Li Shuo Chen Guang‐xing Liang Ping Fan Dongyan xu Meng Wei Yue‐xing Chen Shenzhen Key Laboratory of Advanced Thin Films and Applications Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhenChina Department of Mechanical and Automation Engineering The Chinese University of Hong KongSha TinChina

Use of a flexible thermoelectric source is a feasible approach to realizing selfpowered wearable electronics and the Internet of *** thin films are promising candidates for fabricating flexible power supply,but obtaining highthermoelectric‐performance thin films remains a big *** the present work,a p‐type Bi_(x)Sb_(2−x)Te_(3)thin film is designed with a high figure of merit of 1.11 at 393 K and exceptional flexibility(less than 5%increase in resistance after 1000 cycles of bending at a radius of∼5 mm).The favorable comprehensive performance of the Bi_(x)Sb_(2−x)Te_(3)flexible thin film is due to its excellent crystallinity,optimized carrier concentration,and low elastic modulus,which have been verified by experiments and theoretical ***,a flexible device is fabricated using the prepared p‐type Bi_(x)Sb_(2−x)Te_(3)and n‐type Ag_(2)Se thin ***,an outstanding power density of∼1028μWcm^(−2)is achieved at a temperature difference of 25 *** work extends a novel concept to the fabrication of highperformance flexible thin films and devices for wearable energy harvesting.

关键词： Bi_(x)Sb_(2−x)Te_(3) electrical transport properties flexibility thermoelectric