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Counterexamples Concerning Quasiconformal Extensions of Strongly Starlike Functions

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Acta Mathematica Sinica,English Series 2007年第10期23卷 1859-1868页

作者： yu liang shen Department of Mathematics Suzhou University Suzhou 215006 P. R. China

M. Fait, J. Krzyz and J. Zygmunt proved that a strongly starlike function of order α on the unit disk can be extended to a k-quasiconformal mapping with k ≤ sin（απ/2） on the whole complex plane C which fixes the point at infinity. An open question is whether such a function can be extended to a k-quasiconformal mapping with k 〈α to the whole plane C. In this paper we will give a negative approach to the question.

关键词： strongly starlike function quasiconformal extension Schwarzian derivative Teichmiiller mapping

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On Grunsky operator

Science China Mathematics 2007年第12期50卷 1805-1817页

作者： yu-liang shen Department of Mathematics Suzhou University Suzhou 215006 China

We discuss the holomorphic dependance and the compactness of the Grunsky operator for a univalent function.

关键词： univalent function, quasiconformal mapping, Grunsky operator, compact operator,Hilbert-Schmidt operator

On Holomorphic Sections in Teichmiiller Spaces

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Acta Mathematica Sinica,English Series 2009年第12期25卷 2023-2034页

作者： Ming Feng SUN yu liang shen Department of Mathematics Soochow University Suzhou 215006 P. R. China

It is proved that, for any elementary torsion free Fuchsian group F, the natural projection from the Teichmiiller curve V（F） to the Teichmiiller space T（F） has no holomorphic section.

关键词： Teichmuller space Bers fiber space Teichmiiller curve holomorphic section punctureforgetting mapping

Analysis and experimental study on resistance-increasing behavior of composite high efficiency autonomous inflow control device

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Petroleum Science 2024年第2期21卷 1290-1304页

作者： liang-liang Dong yu-Lin Zhang School of Mechatronic Engineering Southwest Petroleum UniversityChengdu610500SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina Oil and Gas Equipment Technology Sharing and Service Platform of Sichuan ProvinceChengdu610500SichuanChina

Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore. Autonomous inflow control device(AICD) is an important instrument maintain normal production after bottom water coning, however, the resistance increasing ability of the swirl type AICD is insufficient at present, which seriously affects the water control effect. Aiming this problem, this paper designs a multi-stage resistance-increasing and composite type AICD. The separation mechanism of oil-water two phases in this structure, the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed. Establishing the dual-phase multi-stage separation and resistance-increasing model, and verified by measuring the throttling pressure drop and oil-water volume fraction of the AICD, it is found that the composite type AICD has the effect of ICD and AICD at the same time, which can balance the production rate of each well section at the initial stage of production, delay the occurrence of bottom water coning. In the middle and later stages of production, water-blocking can be effectively increased to achieve water control and stable *** structural sensitivity analysis, the influence law of various structural parameters on the water control performance of composite AICD was obtained. The simulation calculation results show that,compared with the existing swirl type AICD, composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average. The composite AICD is suitable for the entire stage of horizontal well production.

关键词： Water control Flow separation Flow resistance-increasing AICD device Simulation and experiment

Distributed Deep Reinforcement Learning:A Survey and a Multi-player Multi-agent Learning Toolbox

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Machine Intelligence Research 2024年第3期21卷 411-430页

作者： Qiyue Yin Tongtong yu shengqi shen Jun Yang Meijing Zhao Wancheng Ni Kaiqi Huang Bin liang liang Wang Institute of Automation Chinese Academy of SciencesBeijing 100190China School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100049China Department of Automation Tsinghua UniversityBeijing 100084China Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of SciencesBeijing 100190China

With the breakthrough of AlphaGo,deep reinforcement learning has become a recognized technique for solving sequential decision-making *** its reputation,data inefficiency caused by its trial and error learning mechanism makes deep reinforcement learning difficult to apply in a wide range of *** methods have been developed for sample efficient deep reinforcement learning,such as environment modelling,experience transfer,and distributed modifications,among which distributed deep reinforcement learning has shown its potential in various applications,such as human-computer gaming and intelligent *** this paper,we conclude the state of this exciting field,by comparing the classical distributed deep reinforcement learning methods and studying important components to achieve efficient distributed learning,covering single player single agent distributed deep reinforcement learning to the most complex multiple players multiple agents distributed deep reinforcement ***,we review recently released toolboxes that help to realize distributed deep reinforcement learning without many modifications of their non-distributed *** analysing their strengths and weaknesses,a multi-player multi-agent distributed deep reinforcement learning toolbox is developed and released,which is further validated on Wargame,a complex environment,showing the usability of the proposed toolbox for multiple players and multiple agents distributed deep reinforcement learning under complex ***,we try to point out challenges and future trends,hoping that this brief review can provide a guide or a spark for researchers who are interested in distributed deep reinforcement learning.

关键词： Deep reinforcement learning distributed machine learning self-play population-play toolbox

CMOS-level mega-pixel organic camera chips made of photocrosslinked photovoltaic nanocells

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Science China Materials 2024年第9期67卷 3043-3045页

作者： Yegang liang Zhuoran Wang Guozhen shen School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing100081China

Organic and hybrid optoelectronics have been driving the frontiers in displays,sensing,and energy in recent decades due to their superior performance,low-cost high-yield manufacturing,and new form factor of mechanical flexibility that is promising for lightweight and wearable applications[1-3].However,the inherent vulnerability makes organic semiconductors incompatible with conventional semiconductor microfabrication,posing significant challenges in high density integration to compete with the resolution of conventional image sensors[4].

关键词： frontier driving lightweight

High-precision X-ray polarimeter based on channel-cut crystals

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Nuclear Science and Techniques 2024年第3期35卷 30-39页

作者： Shang-yu Si Zhong-liang Li Wen-Hong Jia Lian Xue Hong-Xin Luo Jian-Cai Xu Bai-Fei shen Lin-Gang Zhang liang-liang Ji yu-Xin Leng Ren-Zhong Tai Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China

We report on using synthetic silicon for a high-precision X-ray polarimeter comprising a polarizer and an analyzer,each based on a monolithic channel-cut crystal used at multiple Brewster reflections with a Bragg angle very close to 45°.Experiments were performed at the BL09B bending magnet beamline of the Shanghai Synchrotron Radiation Facility using a Si(800)crystal at an X-ray energy of 12.914 keV.A polarization purity of 8.4×10^(-9)was *** result is encouraging,as the measured polarization purity is the best-reported value for the bending magnet ***,this is the firstly systematic study on the hard X-ray polarimeter in China,which is crucial for exploring new physics,such as verifying vacuum birefringence.

关键词： X-ray polarimeter Vacuum birefringence Synchrotron radiation Channel-cut crystal

Recent progress of cobalt-based electrocatalysts for water splitting: Electron modulation, surface reconstitution, and applications

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Nano Research 2024年第4期17卷 2234-2269页

作者： Zhijian liang Di shen Lei Wang Honggang Fu Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People’s Republic of ChinaHeilongjiang UniversityHarbin 150080China

Electrocatalytic water splitting is an essential and effective means to produce green hydrogen energy structures,so it is necessary to develop non-precious metal catalysts to replace precious ***-based catalysts present effective alternatives due to the diverse valence states,adjustable electronic structures,and plentiful *** this review,the catalytic mechanisms of hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)for electrocatalytic water splitting are ***,the synthesis strategies of various cobalt-based catalysts are systematically summarized,followed by the relationships between the structure and performance ***,the effects of d-band center and spin regulation for cobalt-based catalysts are also ***,the dynamic electronic and structural devolution of cobalt-based catalysts are elucidated by combining a series of in-situ ***,we highlight the challenges and future developed directions of cobalt-based catalysts for electrocatalytic water splitting.

关键词： cobalt-based electrocatalysts water splitting electron modulation surface reconfiguration

Strain-promoted S-arylation and alkenylation of sulfinamides using arynes and cyclic alkynes

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Science China Chemistry 2024年第3期67卷 928-935页

作者： Xi Zou Boming shen Gao-lin Li Qian liang Yanhua Ouyang Binghe Yang Peiyuan yu Bing Gao State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical EngineeringInstitute of Chemical Biology and NanomedicineHunan UniversityChangsha 410082China Department of Chemistry and shenzhen Grubbs Institute Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhen 518055China

The conversion of commercially available chiral sulfinamides into pharmaceutically useful chiral sulfoximines via direct SIVfunctionalization is synthetically attractive but challenging due to the competitive reaction of N-functionalization. Herein, we disclose a novel strain-release strategy to access stereospecific and chemoselective SIV-arylation and alkenylation of sulfinamides using arynes and strained cyclic alkynes. This method tolerates an unprecedented chemical diversity of functional groups attached to the nitrogen center(N-R). The origin of the high SIV-selectivity is elucidated by density functional theory calculations, suggesting a stepwise mechanism for the aryne substrates and a concerted mechanism for the cyclic alkynes.

关键词： arylation alkenylation sulfoximines sulfinamides arynes