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Kriging Model Averaging Based on Leave-One-Out Cross-Validation Method

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Journal of Systems Science & Complexity 2024年第5期37卷 2132-2156页

作者： FENG Ziheng zong Xianpeng XIE Tianfa ZHANG Xinyu school of Mathematics Statistics and MechanicsBeijing University of TechnologyBeijing 100124China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

In recent years,Kriging model has gained wide popularity in various fields such as space geology,econometrics,and computer *** a result,research on this model has *** this paper,the authors propose a model averaging estimation based on the best linear unbiased prediction of Kriging model and the leave-one-out cross-validation method,with consideration for the model *** authors present a weight selection criterion for the model averaging estimation and provide two theoretical justifications for the proposed ***,the estimated weight based on the proposed criterion is asymptotically optimal in achieving the lowest possible prediction ***,the proposed method asymptotically assigns all weights to the correctly specified models when the candidate model set includes these *** effectiveness of the proposed method is verified through numerical analyses.

关键词： Asymptotic optimality best linear unbiased prediction cross-validation Kriging model model averaging

Latest progress on interactions between VLF/ELF waves and energetic electrons in the inner magnetosphere

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Science china Earth sciences 2010年第3期53卷 317-326页

作者： XIAO FuLiang1,2, zong QiuGang3, SU ZhenPeng4, TIAN Tian3 & ZHENG HuiNan4 1 school of Physics and Electronic sciences, Changsha university of Science and Technology, Changsha 410004, china 2 State Key Laboratory of Space Weather, Chinese Academy of sciences, beijing 100190, china 3 Institute of Space Physics and Applied Technology, peking university, beijing 100871, china 4 CAS Key Lab for Basic Plasma Science, school of Earth and Space sciences, university of Science and Technology of china, Hefei 230026, china 1. school of Physics and Electronic sciences Changsha University of Science and Technology Changsha 410004 China2. State Key Laboratory of Space Weather Chinese Academy of Sciences Beijing 100190 China3. Institute of Space Physics and Applied Technology Peking University Beijing 100871 China4. CAS Key Lab for Basic Plasma Science School of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China

Interactions between very/extremely low frequency (VLF/ELF) waves and energetic electrons play a fundamental role in dynamics occurring in the inner magnetosphere. Here, we briefly discuss global properties of VLF/ELF waves, along with the variability of the electron radiation belts associated with wave-particle interactions and radial diffusion. We provide cases of electron loss and acceleration as a result of wave-particle interactions primarily due to such waves, and particularly some preliminary results of 3D evolution of phase space density from our currently developing 3D code. We comment on the existing mechanisms responsible for acceleration and loss, and identify several critical issues that need to be addressed. We review latest progress and suggest open questions for future investigation.

关键词： wave-particle interaction VLF/ELF waves energetic electrons acceleration and loss inner magnetosphere

Domain wall network:A dual solution for gravitational waves and Hubble tension?

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Science china(Physics,Mechanics & Astronomy) 2024年第11期67卷 39-46页

作者： Ligong Bian Shuailiang Ge Changhong Li Jing Shu Junchao zong Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics Chongqing UniversityChongqing 401331China Center for High Energy Physics Peking UniversityBeijing 100871China school of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan ProvinceSchool of Physics and AstronomyYunnan UniversityKunming 650091China beijing Laser Acceleration Innovation Center Beijing 101400China Department of Physics Nanjing UniversityNanjing 210093China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China

We explore the possibility that domain wall networks generate the stochastic gravitational wave background(SGWB) observed as a strong common power-law process in the Data Release-2 of Parkes Pulsar Timing Array. We find that a broad range of parameters, specifically wall tension around σ_(DW)^(29-414 TeV)^(3) and wall-decay temperature within T_(d) ~ 20-257 MeV, can explain this phenomenon at a 68% credible level. Meanwhile, the same parameters could ease the Hubble tension if particles from these domain wall networks decay into dark radiation. We establish a direct analytical relationship, ΩGW(f_(p), T_(0))h^(2)~ Ω_(rad)h^(2)(Ω_νΩN_(eff))^(2),to illustrate this coincidence, underlining its importance in the underlying physics and potential applicability to a wider range of models and data. Conversely, if the common power-law process is not attributed to domain wall networks, our findings impose tight limits on the wall tension and decay temperature.

关键词： domain wall gravitational waves Hubble tension

Characterization for commutators of n-dimensional fractional Hardy operators

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Science china Mathematics 2007年第10期50卷 1418-1426页

作者： Zun-wei FU~(1,2) zong-guang LIU~3 Shan-zhen LU~(1+) Hong-bin WANG~3 ~1 school of mathematical sciences,beijing Normal university,beijing 100875,china ~2 Department of Mathematics,Linyi Normal university,Linyi 276005,china ~3 Department of Mathematics,china university of Mining and Technology (beijing),beijing 100083,china 1. school of mathematical sciences Beijing Normal University Beijing 100875 China 2. Department of Mathematics Linyi Normal University Linyi 276005 China 3. Department of Mathematics China University of Mining and Technology (Beijing) Beijing 100083 China

In this paper,it was proved that the commutator H_(β,b)generated by an n-dimensional fractional Hardy operator and a locally integrable function b is bounded from L^(p1)(R^n)to L^(p2)(R^n)if and only if b is a CMO(R^... 详细信息

关键词： n-dimensional fractional Hardy operator, commutator, C(M)O function, homogeneous Herz space

A flexible,modular and versatile functional part assembly toolkit for gene cluster engineering in Streptomyces

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Synthetic and Systems Biotechnology 2024年第1期9卷 69-77页

作者： Xuejin Zhao Yeqing zong Qiuli Lou Chenrui Qin Chunbo Lou CAS Key Laboratory of Pathogenic Microbiology and Immunology Institute of MicrobiologyChinese Academy of SciencesBeijing100101China CAS Key Laboratory of Microbial Physiological and Metabolic Engineering Institute of MicrobiologyChinese Academy of SciencesBeijing100101China Center for Cell and Gene Circuit Design Key Laboratory of Quantitative Synthetic BiologyShenzhen Institute of Synthetic BiologyShenzhen Institutes of Advanced TechnologyChinese Academy of Sciences1068 Xueyuan AvenueUniversity TownNanshanShenzhen518055China peking-Tsinghua Joint Center for Life sciences Peking UniversityBeijing100871China Center for Quantitative Biology Academy for Advanced Interdisciplinary StudiesSchool of PhysicsPeking UniversityBeijing100871China College of Life sciences University of Chinese Academy of SciencesBeijing100149China

Streptomyces has enormous potential to produce novel natural products(NPs)as it harbors a huge reservoir of uncharacterized and silent natural product biosynthetic gene clusters(BGCs).However,the lack of efficient gene cluster engineering strategies has hampered the pace of new drug ***,we developed an easy-to-use,highly flexible DNA assembly toolkit for gene cluster *** DNA assembly toolkit is compatible with various DNA assembling approaches including Biobrick,Golden Gate,CATCH,yeast homologous recombination-based DNA assembly and homing endonuclease-mediated *** compatibility offers great flexibility in handling multiple genetic parts or refactoring large gene *** demonstrate the utility of this toolkit,we quantified a library of modular regulatory parts,and engineered a gene cluster(act)using characterized promoters that led to increased ***,this work provides a powerful part assembly toolkit that can be used for natural product discovery and optimization in Streptomyces.

关键词： Streptomyces Standard toolkit DNA assembly Gene cluster Synthetic biology

Permeable carbon fiber based thermoelectric film with exceptional EMI shielding performance and sensor capabilities

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Journal of Advanced Ceramics 2024年第8期13卷 1119-1131页

作者： Junjie Zhu Chuan Sun Wanlin Feng Mengran Chen Peng-An zong Chunlei Wan College of Materials Science and Engineering Nanjing Tech UniversityNanjing 211800China Nationai Innovation Institute of Defense Technology Academy of Military Sciences of the People's Liberation Army of ChinaBeijing 100089China Institute of Nuclear Physics and Chemistry Innovation Research Team for Advanced CeramicsChina Academy of Engineering PhysicsMianyang 621900China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Thermoelectric(TE)technologies offer a promising approach for directly converting skin heat into electricity for wearable *** p-type Sb2Tes and n-type BizTes as top-performing materials at room temperature,their rigid inorganic structure,with ultralow moisture permeability,poses challenges in warm and humid conditions,fostering bacterial growth and potential skin *** address this issue,we developed a cross-linked core-shell structure by electrodepositing Sb_(2)Te_(3)(Bi_(2)Te_(3))onto carbon fiber(CF).This architecture significantly improved the electrical conductivity and the Seebeck coefficient,resulting in a remarkable 300-fold increase in the power factor compared to that of pure *** CF/Sb_(2)Te_(3) and CF/Bi2Te films demonstrated optimal power factors of 450 and 121μW·m^(-1)·K^(-2),***,the fabricated films exhibited outstanding moisture permeability,over 3000 g·m^(-2)·d^(-1),exceptional electromagnetic interference shielding efficiency approaching 93 dB,and versatility as sensors for language assistance and respiratory *** attributes underline their broad applicability,emphasizing their suitability for human health protection in diverse scenarios.

关键词： thermoelectric(TE) carbon fiber(CF) Bi_(2)Te_(3) electrodeposition moisture permeability electromagnetic interference shielding

Highly Aligned Graphene Aerogels for Multifunctional Composites

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Nano-Micro Letters 2024年第6期16卷 276-342页

作者： Ying Wu Chao An Yaru Guo Yangyang zong Naisheng Jiang Qingbin Zheng Zhong‑Zhen Yu beijing Advanced Innovation Center for Materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083People’s Republic of China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004People’s Republic of China school of Science and Engineering The Chinese University of Hong KongShenzhenShenzhenGuangdong 518172People’s Republic of China State Key Laboratory of Organic‑Inorganic Composites College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China

Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,and thermal *** maximize the utilization of graphene’s in-plane properties,pre-constructed and aligned structures,such as oriented aerogels,films,and fibers,have been *** unique combination of aligned structure,high surface area,excellent electrical conductivity,mechanical stability,thermal conductivity,and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions,enabling advancements in diverse *** review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their *** highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and *** oriented scaffolds endow graphene aerogels and their composites with anisotropic properties,showing enhanced electrical,mechanical,and thermal properties along the alignment at the sacrifice of the perpendicular *** review showcases remarkable properties and applications of aligned graphene aerogels and their composites,such as their suitability for electronics,environmental applications,thermal management,and energy *** and potential opportunities are proposed to offer new insights into prospects of this material.

关键词： Highly aligned graphene aerogels Quantitative characterization of alignment Multifunctional composites Anisotropic properties Multifunctional applications

Influence of expressed TRAIL on biophysical properties of the human leukemic cell line Jurkat

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Cell Research 2004年第2期14卷 161-168页

作者： Kai CHEN~(1,*), Dan LI~(1,*), Yu Hui JIANG~1, Wei Juan YAO~1, Xin Juan WANG~2, Xiao Chao WEI~2, Jing GAO~3, Li De XIE~1, zong Yi YAN~4, zong Yao WEN~(1**), Shu CHIEN~5 ~1Hemorheology Center, Department of Biophysics, school of Basic Medical sciences, peking university, beijing, 100083, china. ~2Department of Biochemical and Molecular Biology, school of Basic Medical sciences, peking university, beijing, 100083, china. ~3Department of Urology, Medical Center, New York university, USA. ~4Department of Mechanics and Engineering Science, peking university, beijing 100871, china. ~5Department of Bioengineering and Whitaker Institute of Biomedical Engineering, university of California, San Diego, La Jolla, CA 92093-0412, USA 1Hemorheology Center Department of Biophysics School of Basic Medical Sciences Peking University Beijing 100083 China. 1Hemorheology Center Department of Biophysics School of Basic Medical Sciences Peking University Beijing 100083 China. 1Hemorheology Center Department of Biophysics School of Basic Medical Sciences Peking University Beijing 100083 China. 1Hemorheology Center Department of Biophysics School of Basic Medical Sciences Peking University Beijing 100083 China. 2Department of Biochemical and Molecular Biology School of Basic Medical Sciences Peking University Beijing 100083 China. 2Department of Biochemical and Molecular Biology School of Basic Medical Sciences Peking University Beijing 100083 China. 3Department of Urology Medical Center New York University USA. 1Hemorheology Center Department of Biophysics School of Basic Medical Sciences Peking University Beijing 100083 China. 4Department of Mechanics and Engineering Science Peking University Beijing 100871 China. 1Hemorheology Center Department of Biophysics School of Basic Medical Sciences Peking University Beijing 100083 China. 5Department of Bioengineering and Whitaker Institute of Biomedical Engineering University of California San Diego La Jolla CA 92093-0412 USA

The cDNA fragment of human TRAIL (TNF-related apoptosis inducing ligand) was cloned into RevTet-On, a Tetregulated and high-level gene expression system. The gene expression system was constructed in a human leukemic cell line: Jurkat. By using RevTet-On TRAIL gene expression system in Jurkat as a cell model, we studied the influence of TRAIL gene on the changes of cellular apoptosis before and after the TRAIL gene expression, which was induced by adding tetracycline derivative doxycycline (Dox). The results indicated that the cellular apoptosis ratio was largely dependent on the TRAIL gene expression level. Moreover, it was found that the apoptosis-inducing TRAIL could cause significant changes in the biophysical properties of Jurkat cells. The cell surface charge density decreased, the membrane fluidity declined, the elastic coefficients K_I increased, and the proportion of α-helix in membrane protein secondary structure decreased. Thus, the apoptosis-inducing TRAIL gene caused significant changes on

关键词： TRAIL Tet gene expression system Jurkat apoptosis.

Simulation studies of high-latitude magnetospheric boundary dynamics

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Science china(Technological sciences) 2004年第4期47卷 421-435页

作者： PU Zuyin1, SHI Quanqi1,3, XIAO Chijie1, FU Suiyan1, ZHANG Hui1,2, zong Qiugang2 & LIU Zhenxing3 1. school of Earth and Space sciences, peking university, beijing 100871, china 2. Center for Space Physics, Boston university, 725 Commonwealth Avenue, Boston, MA 02215, USA 3. Center for Space Science and Application Research, Chinese Academy of sciences, beijing 100080, china 1. school of Earth and Space sciences Peking University 100871 Beijing China 2. Center for Space Science and Application Research Chinese Academy of Sciences 100080 Beijing China 3. Center for Space Physics Boston University 725 Commonwealth Avenue 02215 Boston MA USA

Magnetic reconnection at the high-latitude magnetopause is studied using 2.5-dimensional Hall-MHD simulation. Concentric flow vortices and magnetic islands appear when both Hall effect and sheared flow are considered. Plasma mixing across the magnetopause occurs in the presence of the flow vortices. Reconnected structure generated in the vicinity of the subsolar point changes its geometry with increasing flow shear while moving to high latitudes. In the presence of flow shear, with the Hall-MHD reconnection a higher reconnection rate than with the traditional MHD is obtained. The out-of-plane components of flow and magnetic field produced by the Hall current are redistributed under the action of the flow shear, which makes the plasma transport across the boundaries more complicated. The simulation results provide some help in understanding the dynamic processes at the high latitude magnetopause.

关键词： magnetopause, entry layer, magnetic reconnection, vortex reconnection, Hall effect, flow shear.