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Supermassive black holes triggered by QCD axion bubbles

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Communications in Theoretical Physics 2024年第5期76卷 134-139页

作者： Hai-Jun Li Ying-Quan Peng wei chao Yu-Feng zhou Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical Physics Asia-Pacific Beijing/HangzhouChina

Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still *** this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion *** this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after *** QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase *** consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))*** PBHs at this mass region may account for the seeds of SMBHs.

关键词： supermassive black holes primordial black holes quantum chromodynamics axion

Simple and efficient method for synthesis of metallodeutero-porphyrin derivatives bearing symmetrical disulphide bond

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Chinese Chemical Letters 2011年第5期22卷 527-530页

作者： Cheng Guo Sun Bing Cheng Hu wei You zhou Shi chao Xu Quan Zhi Deng Zu Liang Liu School of Chemical Engineering Nanjing University of Science and Technology Nanjing 210094 China

A novel thiol-derivative porphyrin[2,7,12,18-tetramethyl-13,17-di（3-disulfidepropyl）porphyrin]bearing the symmetrical disulphide bond and its metal complexes have been successfully prepared by means of modification ... 详细信息

关键词： Deuteroporphyrin Disulphide bond Synthesis

Multiple damage zones around hydraulic fractures generated by high-frequency pulsating hydraulic fracturing

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Petroleum Science 2024年第4期21卷 2688-2702页

作者： Yan Peng Sheng-Jie wei Guang-Qing Zhang Da-wei zhou Chuang-chao Xu School of Petroleum Engineering China University of Petroleum PetroChina Changqing Oilfield Company

Pulsating hydraulic fracturing(PHF) is a promising fracturing method and can generate a dynamic periodic pressure. The periodic pressure can induce fatigue failure of rocks and decrease initiation pressure of fracture. If the frequency of periodic pressure exceeds 10 Hz, the distribution of pressure along the main fracture will be heterogeneous, which is much different from the one induced by the common fracturing method. In this study, the impact of this special spatial feature of pressure on hydraulic fracture is mainly investigated. A coupled numerical simulation model is first proposed and verified through experimental and theoretical solutions. The mechanism of secondary fracture initiation around the main fracture is then discovered. In addition, sensitivity studies are conducted to find out the application potential of this new method. The results show that(1) this coupled numerical simulation model is accurate. Through comparison with experimental and theoretical data, the average error of this coupled model is less than 1.01%.(2) Even if a reservoir has no natural fracture, this heterogeneous distribution pressure can also cause many secondary fractures around the main fracture.(3) The mechanism of secondary fracture initiation is that this heterogeneous distribution pressure causes tensile stress at many locations along the main fracture.(4) Through adjusting the stimulation parameters, the stimulation efficiency can be improved. The average and amplitude of pressure can increase possibility of secondary fracture initiation. The frequency of this periodic pressure can increase number of secondary fractures. Even 6 secondary fractures along a 100 m-length main fracture can be generated.(5) The influence magnitudes of stimulation parameters are larger than ones of geomechanical properties, therefore, this new fracturing method has a wide application potential.

关键词： Tight reservoir Reservoir stimulation Numerical simulation Secondary fracture Fracture initiation

One-Pot Stereoselective Synthesis of Different Fused Multicyclic Iminosugars Based on the Iminium-lon Intermediate

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Chinese Journal of Chemistry 2024年第2期42卷 142-150页

作者： Song Xie Jilai Wu Likai zhou chao wei Xiaoliu Li Hua Chen Key Laboratoryof Chemical Biology of Hebei Province College of Chemistry and Material ScienceHebei UniversityBaodingHebei 071002China College of Chemistry and Chemical Engineering Xingtai UniversityXingtaiHebei 054001China

Different novel fused multicyclic iminosugars were synthesized from D-ribose tosylate,aniline and vinyl ethyl ether by one-pot three-component stereoselective[4+2]reaction at different *** iminium-ion is the key intermediate for the *** a result,several complex fused iminosugars 3a were obtained by aza-Diels-Alder mechanism at 60℃,while a series of aza-C-glycosides 5a were prepared by Mannich reaction at room temperature accompanied by another tetrahydroquinoline-fused iminosugars 4a(tricyclic derivatives)through aza-Diels-Alder *** strategy will help to construct structurally diverse and bioactive iminosugar analogues.

关键词： Fused multicyclic iminosugar Aza-Diels-Alder cycloaddition Mannich reaction Tetrahydroquinoline Multicomponent reactions Enantioselectivity Cyclization

Polyoxometalates-derived nanostructures for electrocatalysis application

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Rare Metals 2024年第5期43卷 1845-1866页

作者： chao-Yue Sun Wen Li Kai Wang wei-Jia zhou Hai-Qing Wang Institute for Advanced Interdisciplinary Research(iAIR) College of Chemistry and Chemical EngineeringUniversity of JinanJinan250022China Shandong Electrical Engineering and Equipment Group Intelligent Electric Co. Ltd.Jinan 250022China

The conversion of intermittent renewable electrical energy to chemical energy is of great importance which can not only mitigate current energy and environmental crisis but also contribute to the ongoing carbon neutrality national *** is serving as a low-carbon conversion technology that enables green and efficient energy conversion mainly through hydrogen evolution reaction(HER),carbon dioxide reduction reaction(CO_(2)RR),and nitrogen reduction reaction(NRR).The core of electrocatalysis is the design and construction of low-cost high-activity and high-stability electrocatalyst to drive reaction thermodynamics and *** employment of polyoxometalates(POMs)as platforms or precursors to construct different types of electrocatalysts has been widely ***,we systematically summarized the recent advances in POM-derived nanostructures for electrocatalysis *** strategies for precursor design and electrocatalyst synthesis were briefly *** morphology control,phase control,composite modulation,and heterostructure engineering in POM-derived nanostructures were presented in *** structure–activity relationship of POM-derived nanostructures is fully discussed for HER CO_(2)RR,and NRR ***,the current challenges and future outlooks of POM-derived nanostructures are summarized to provide insights toward high-efficiency electrocatalysts for energy conversion technologies.

关键词： Microforming Cylindrical compression Size effects Grain orientation Inhomogeneous deformation

Panchev系统的全局指数吸引集及其应用

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控制理论与应用 2013年第1期30卷 84-88页

作者：魏周超中国地质大学数学与物理学院湖北武汉430074

通过构造广义正定径向无界的Lyapunov函数,研究了一个包含三维Lorenz系统在内的Panchev系统的全局指数吸引集和正向不变集,得到了三维圆柱估计,并用数值仿真验证了三维圆柱估计式的有效性.然后利用一个非线性控制器将得到的全局指数吸... 详细信息

通过构造广义正定径向无界的Lyapunov函数,研究了一个包含三维Lorenz系统在内的Panchev系统的全局指数吸引集和正向不变集,得到了三维圆柱估计,并用数值仿真验证了三维圆柱估计式的有效性.然后利用一个非线性控制器将得到的全局指数吸引集的结果应用到混沌同步中,研究了该系统的全局指数同步问题.

关键词： Panchev系统全局指数吸引集正向不变集混沌同步

Intelligent feedforward gust alleviation based on neural network

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Chinese Journal of Aeronautics 2024年第3期37卷 116-132页

作者： Yitao zhou Zhigang WU chao YANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

This paper proposes a neural network-based intelligent feedforward gust alleviation framework,which includes a neural network identification model and a neural network controller.A neural network training dataset is formed by collecting flight data and the gust data encountered during the aircraft flight.A neural network identification model is first trained to accurately predict the aircraft’s ***,based on the output of the identification model and the collected flight data,the parameters of the time-delay neural network controller are obtained through a learning *** simulation results show that the designed intelligent controller has good gust alleviation effects for both continuous turbulence excitation and discrete gust *** example,when the aircraft is 40000 kg and the flight speed is 0.81Ma,the controller achieves a 67.82%reduction in wingtip acceleration and a 35.90%reduction in center of mass acceleration under continuous turbulence *** considering the measurement uncertainties,such as noise existing in the collected data,the trained controller can still achieve an acceptable gust alleviation ***,considering a flight in which the aircraft mass is constantly changing,the intelligent controller,which continuously learns from new flight data,maintains a good gust alleviation effect throughout the flight.

关键词： Gust alleviation Intelligent control Feedforward control Neural networks Time-varying aircraft

Transient Response and Ionic Dynamics in Organic Electrochemical Transistors

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Nano-Micro Letters 2024年第11期16卷 191-223页

作者： chao Zhao Jintao Yang wei Ma State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi′an 710049People’s Republic of China

The rapid development of organic electrochemical transistors(OECTs)has ushered in a new era in organic electronics,distinguishing itself through its application in a variety of domains,from high-speed logic circuits to sensitive biosensors,and neuromorphic devices like artificial synapses and organic electrochemical random-access *** recent strides in enhancing OECT performance,driven by the demand for superior transient response capabilities,a comprehensive understanding of the complex interplay between charge and ion transport,alongside electron–ion interactions,as well as the optimization strategies,remains *** review aims to bridge this gap by providing a systematic overview on the fundamental working principles of OECT transient responses,emphasizing advancements in device physics and optimization *** review the critical aspect of transient ion dynamics in both volatile and non-volatile applications,as well as the impact of materials,morphology,device structure strategies on optimizing transient *** paper not only offers a detailed overview of the current state of the art,but also identifies promising avenues for future research,aiming to drive future performance advancements in diversified applications.

关键词： Organic electrochemical transistors Transient response Ion dynamics Electronic dynamics Volatility and non-volatility

Sensing properties and mechanisms of LaF_(3)-Co_(3)O_(4) nanorods for low-concentration methanol detection

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Rare Metals 2024年第5期43卷 2193-2204页

作者： Xiao-Xi He Hong-Feng Chai Yi-Wen zhou Ke-wei Liu Ze-Xin Yu chao Zhang College of Mechanical Engineering Yangzhou UniversityYangzhou225127China Institutefor Manufacturing Technologies of Ceramic Components and Composites(IMTCCC) University of Stuttgart70569 StuttgartGermany

Methanol is one of the characteristic gases that distinguish between healthy individuals and lung cancer(LC)lesions in exhaled human *** concentration in exhaled breath is generally below one part per million(1×10^(-6)).The second-phase composite is widely regarded as one of the methods to improve the gas-sensing perfor-mance of metal oxide semiconductor(MOS)*** this study,LaF_(3)-Co_(3)O_(4) was synthesized by a simple hydrothermal method to enhance its low-concentration methanol gas-sensing performance.5 at%LaF_(3)-Co_(3)O_(4) nanorods exhibited excellent methanol detection performance,including a wider linear detection concentration range(0.2×10^(-6)~5×10^(-6)),a response value exceeding 4.0 for 1×10^(-6)methanol at 275°C and 75%relative humidity(RH),long-term stability(maximum deviation within 15%over 2 weeks),and excellent *** mechanism of performance enhancement was studied using various techniques,and density functional *** special spinel structure of Co_(3)O_(4),the high ionic migration of F-in LaF_(3),the larger specific surface area of 5 at%LaF_(3)-Co_(3)O_(4) nanorods,and the generated crystal defects all explain the excellentmethanol gas-sensing *** work provides a novel route to prepare MOS composite materials for low-concentration methanol gas detection.

关键词： Gas sensor LaF_(3) Co_(3)O_(4) Methanol Lung cancer