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Controllability of the Heat Equation with a Control Acting on a Measurable Set

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Chinese Annals of Mathematics,Series B 2012年第1期33卷 149-160页

作者： hang yu School of Mathematical Sciences Fudan UniversityShanghai 200433China

The paper deals with the controllability of a heat equation. It is well-known that the heat equation yt - △y = uxE in （0, T） × Ω with homogeneous Dirichlet boundary conditions is null controllable for any T 〉 0 and any open nonempty subset E of Ω. In this note, the author studies the case that E is an arbitrary measurable set with positive measure.

关键词： Heat equation Measurable sets Null controllability Observabilityinequality

Model-data-driven P-wave impedance inversion using ResNets and the normalized zero-lag cross-correlation objective function

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Petroleum Science 2022年第6期19卷 2711-2719页

作者： yu-hang Sun Yang Liu CNPC Key Laboratory of Geophysical Prospecting and State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China China University of Petroleum(Beijing) Karamay CampusKaramayXinjiang834000China

Model-driven and data-driven inversions are two prominent methods for obtaining P-wave impedance,which is significant in reservoir description and *** on proper initial models,most model-driven methods primarily use the limited frequency bandwidth information of seismic data and can invert P-wave impedance with high accuracy,but not high *** data-driven methods mainly employ the information from well-log data and can provide high-accuracy and highresolution P-wave impedance owing to the superior nonlinear curve fitting capacity of neural ***,these methods require a significant number of training samples,which are frequently *** obtain P-wave impedance with both high accuracy and high resolution,we propose a model-data-driven inversion method using Res Nets and the normalized zero-lag cross-correlation objective function which is effective for avoiding local minima and suppressing random *** using initial models and training samples,the proposed model-data-driven method can invert P-wave impedance with satisfactory accuracy and *** on synthetic and field data demonstrate the proposed method’s efficacy and practicability.

关键词： Model-data-driven P-wave impedance inversion Res Nets Zero-lag cross-correlation

Novel bake hardening mechanism for bainite-strengthened complex phase steel

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Journal of Materials Science & Technology 2023年第12期143卷 117-128页

作者： hang yu yu Yan Cheng Zhang Lijie Qiao Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Corrosion and Protection Center University of Science and Technology BeijingBeijing 100083China

In the automobile industry,stamping and paint baking processes are used to strengthen components,and this not only saves costs,but also further reduces the bodyweight of *** this work,the bake hardening mechanism of the complex phase(CP)steel CP980 was explored by comparing it with that of DP1180,which has a clear bake hardening mechanism and a carbon content similar to that of *** analyzing the bake hardening response and the microstructural changes of the two steels,we found that the bake hardening process of CP980 was divided into three *** the first two stages,the carbon atoms diffused into dislocations to form Cottrell atmosphere pinning dislocations,and excess car-bon atoms formed carbon clusters or low-temperature carbide pinning dislocations that were similar to *** the third stage,the dislocation acted as rapid channels for carbon diffusion,and fine cementite gradually formed when the carbon clusters gathered at the dislocations as precursors,resulting in pre-cipitation *** novel bake-hardening(BH)mechanism is crucial for obtaining a comprehensive understanding of the strain-baking behavior of advanced high-strength steals(AHSS).

关键词： Age hardening Bainitic steel Carbon diffusion Cementite Mechanical property Automotive weight reduction

Steered coherence and entanglement in the Heisenberg XX chain under twisted boundary conditions

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Chinese Physics B 2021年第7期30卷 139-144页

作者： yu-hang Sun yu-Xia Xie School of Science Xi'an University of Posts and TelecommunicationsXi'an 710121China

We study steered coherence(SC)and entanglement in a three-spin Heisenberg XX model under twisted boundary conditions and show that their strengths can be significantly enhanced by tuning the twist *** optimal twist angleθ_(opt)for achieving the maximum l_(1) norm of SC isπin the region of weak field B and decreases gradually fromπto 0 when B increases after a critical value,while for the relative entropy of SC,θ_(opt)equalsπin the weak field region and 0 *** entanglement and the critical temperature above which the entanglement vanishes can also be significantly enhanced by tuning the twist angle from 0 toπ.

关键词： quantum coherence entanglement twisted boundary conditions

Null controllability for a fourth order parabolic equation

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Science in China(Series F) 2009年第11期52卷 2127-2132页

作者： yu hang School of Mathematical Sciences Fudan University Shanghai 200433 China

In the paper, the null interior controllability for a fourth order parabolic equation is obtained. The method is based on Lebeau-Rabbiano inequality which is a quantitative unique continuation property for the sum of ... 详细信息

关键词： fourth order parabolic equations null controllability Lebeau-Rabbiano inequality

Graphene Fibers: Advancing Applications in Sensor, Energy Storage and Conversion

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Chinese Journal of Polymer Science 2019年第6期37卷 535-547页

作者： Guan-hang yu Qing Han Liang-Ti Qu Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials Key Laboratory of Cluster Science Ministry of Education School of Chemistry Beijing Institute of Technology

Graphene fibers are a kind of novel carbon fibers assembled by orderly aligned graphene sheets with high flexibility, good conductivity, high thermal conductivity, and low density, which make them possible to be widely used in high-performance and multifunctional compound materials as well as flexible electronic devices. In this review, we summarize the research progress in the synthesis of graphene fibers, and their applications in sensor, energy storage, and energy conversion. Furthermore, the current issues and some prospects for the future trend of graphene fibers are discussed.

关键词： Graphene fibers Assembly Functionalization Sensor Energy storage and conversion

Emerging role of long non-coding RNA in the development of gastric cancer

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World Journal of Gastrointestinal Oncology 2018年第9期10卷 260-270页

作者： hang yu Long Rong Department of Endoscopic Center Peking University First Hospital

Gastric cancer is a common, worldwide malignancy and has a poor prognosis due to late diagnosis. Long non-coding RNAs(lnc RNAs) are a significant subtype of RNA molecules with a length longer than 200 nucleotides(nt) that rarely encode proteins. In recent decades, deregulation of lnc RNAs has been shown to be involved in tumorigenesis and tumor progression in various human carcinomas, including gastric cancer. Accumulating evidence has shown that some lnc RNAs may function as diagnostic biomarkers or therapeutic targets for gastric cancer. Thus, exploring the specific functions of lnc RNAs will help both gain a better understanding of the pathogenesis and develop novel treatments for gastric cancer. In this review, we highlight the expression and functional roles of lncR NAs in gastric cancer, and analyze the potential applications of lncR NAs as diagnostic markers and therapeutic targets.

关键词： Function Tumorigenesis Gastric cancer Therapeutic target Long non-coding RNAs Diagnostic marker

Living Copolymerization of EOVE and MOVE:Fast Flow Synthesis and Thermal Responsive Behavior

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Chinese Journal of Polymer Science 2022年第10期40卷 1193-1200,I0008页

作者： yu-hang He Dan Xie Yang-Cheng Lu State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBejing 100084China

Random and block copolymers of 2-methoxyethyl vinyl ether(MOVE)and 2-ethoxyethyl vinyl ether(EOVE)were synthesized within 180 s via IBVE-HCl/SnCl_(4) initiating system in the presence of THF in a microflow *** polymers can be produced continuously and efficiently with extremely narrow molecular weight distributions(M_(w)/M_(n)=1.09-1.18)even at the existence of pendant oxyethylene units Polymerization rate can be accelerated by reducing THF to very low concentration([THF]=50 mmol/L),reaching conversions over 60%and 70%in 60 s for EOVE and MOVE,*** copolymers poly(MOVE_(100x)-r-EOVE(_(100)(1-x)))(x=0.25,0.5,0.75)experienced very sensitive phase separation process,of which phase separation temperature(T_(ps))can be adjusted between 20 and 70℃by controlling monomer *** the other hand,thermally induced phase separation of diblock copolymers poly(MOVE_(100)-b-EOVE_(100))was not so sensitive as its random copolymer *** bigger difference between phase separation temperatures of heating and cooling process(ΔT_(ps))was found for diblock copolymer.

关键词： Living cationic polymerization Stimuli-responsive Microflow system

Effect of Cr_(2)O_(3) on properties of CaO-SiO_(2)-Fe_(t)O-MgO system and dissolution behavior of lime

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Journal of Iron and Steel Research International 2024年第4期31卷 870-881页

作者： Shan-nan Li Jian-li Li yue yu hang-yu Zhu The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The productivity of the chrome-containing semi-steel converter smelting process is directly affected by the slag-forming speed during the converter preliminary *** effects of Cr_(2)O_(3) content on the physicochemical properties of the CaO-SiO_(2)-Fe_(t)O-MgO system,such as melting temperature,solidification behavior,mineral composition,and lime dissolution rate,were *** results showed that the slag was an amorphous phase at 1500℃.When Cr_(2)O_(3) was added,Ca(Fe,Mg)Si_(2)O_(6) and spinel were formed in the *** the increase in Cr_(2)O_(3) content,the amount of spinel precipitation increased,and the dendritic FegO_(4) crystal gradually changed into the granular(Fe,Mg)(Fe,Cr)2O_(4) *** the Cr_(2)O_(3) content increased from O to 2.91 wt.%,the melting temperature of the slag rose,and the melting range of the slag expanded slightly,but the lime dissolution rate did not *** the Cr_(2)O_(3) content further increased to 9.09 wt.%,the melting temperature continued to rise,the melting range rapidly expanded,and the lime dissolution rate decreased.

关键词： Cr_(2)O_(3) Vanadium-titanium magnetite Converter Slag Lime dissolution