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Experimental investigation about the incipient velocity of spherical particles on a hemispherical bed surface

Particuology 2024年第5期88卷 49-61页

作者： Chuannan li Jie Chen Changbo Jiang xie li Zhiyuan Wu School of Hydraulic and Environmental Engineering Changsha University of Science & TechnologyChangsha 410114China Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province Changsha 410114China Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province Changsha 410114China

The sediment particles play a huge role in shaping the bed load transport.In this research,240 water-tunnel experiments are carried out to investigate the incipient velocity of the observation particles in two particle arrangements.To accurately predict the incipient velocity of the observation particles,the equation is conceived by the rolling instability mechanism.The incipient velocity equations and experimental data are used to analyze the trend of dispersive pressure and the effect of arrangement position on velocity.We find that it is appropriate to choose the coefficient of drag as 0.261 and the coefficient of lift as 0.198 for the incipient velocity equation of spherical particles on the hemispherical bed surface.Furthermore,the dispersive pressure is closely related to the flow state,particle size,and particle arrangement,which leads to the incipient velocity of the observation particle being at a minimum when the interference particle angle is 45°.Finally,the particle spacing and the projected area changed with the arrangements,directly affecting the incipient velocity of the observed particle.The analysis of four aspects for the coefficients,dispersive pressure,different particle spacing,and projected area will facilitate the prediction of particle incipient velocity,especially on hemispherical beds.

关键词： Hemispherical bed surface Observed particle Interference particle Dispersive pressure Incipient velocity

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Vonoprazan 10 mg or 20 mg vs. lansoprazole 15 mg as maintenance therapy in Asian patients with healed erosive esophagitis: A randomized controlled trial

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中华医学杂志(英文版) 2024年第8期137卷 962-971页

作者： Xiao Yinglian Qian Jiaming Zhang Shutian Dai Ning Chun Hoon Jai Chiu Chengtang Chong Chui Fung Funao Nobuo Sakurai Yuuichi Eisner Jessica D. xie li Chen Minhu Beijing 100006 Beijing Friendship Hospital Capital Medical University Beijing 100050 Sir Run Run Shaw Hospital School of Medicine Zhejiang University Hangzhou Zhejiang 310020 Department of Internal Medicine Korea University Anam Hospital Department of Gastroenterology Korea University College of Medicine 73 Goryeodae-ro Seongbuk-gu Seoul 02841 Republic of Korea Department of Gastroenterology & Hepatology linkou Medical Center Chang Gung Memorial Hospital Taoyuan The First Affiliated Hospital Taiwan 33353 Takeda Development Center Asia Singapore 018981 Singapore Takeda Pharmaceutical Company Chuo-ku Osaka 540-8645 Japan Takeda Pharmaceuticals International Company Cambridge Sun Yat-sen University MA 02142 USA China Medical Team Takeda China Beijing 100027 Guangzhou Guangdong 510062 China Peking Union Medical College Hospital Peking Union Medical College Chinese Academy of Medical Sciences

Background: Erosive esophagitis (EE) is a gastroesophageal reflux disease characterized by mucosal breaks in the esophagus. Proton pump inhibitors are widely used as maintenance therapy for EE, but many patients still relapse. In this trial, we evaluated the noninferiority of vonoprazanvs. lansoprazole as maintenance therapy in patients with healed EE.Methods: We performed a double-blind, double-dummy, multicenter, phase 3 clinical trial among non-Japanese Asian adults with endoscopically confirmed healed EE from April 2015 to February 2019. Patients from China, South Korea, and Malaysia were randomized to vonoprazan 10 mg or 20 mg once daily or lansoprazole 15 mg once daily for 24 weeks. The primary endpoint was endoscopically confirmed EE recurrence rate over 24 weeks with a noninferiority margin of 10% using a two-sided 95% confidence interval (CI). Treatment-emergent adverse events (TEAEs) were recorded.Results: Among 703 patients, EE recurrence was observed in 24/181 (13.3%) and 21/171 (12.3%) patients receiving vonoprazan 10 mg or 20 mg, respectively, and 47/184 (25.5%) patients receiving lansoprazole (differences: -12.3% [95% CI, -20.3% to-4.3%] and -13.3% [95% CI, -21.3% to -5.3%], respectively), meeting the primary endpoint of noninferiority to lansoprazole in preventing EE recurrence at 24 weeks. Evidence of superiority (upper bound of 95% CI <0%) was also observed. At 12 weeks, endoscopically confirmed EE recurrence was observed in 5/18, 2/20, and 7/20 of patients receiving vonoprazan 10 mg, vonoprazan 20 mg, and lansoprazole, respectively. TEAEs were experienced by 66.8% (157/235), 69.0% (156/226), and 65.3% (158/242) of patients receiving vonoprazan 10 mg, vonoprazan 20 mg, and lansoprazole, respectively. The most common TEAE was upper respiratory tract infection in 12.8% (30/235) and 12.8% (29/226) patients in vonoprazan 10 mg and 20 mg groups, respectively and 8.7% (21/242) patients in lansoprazole group.Conclusion: Vonoprazan maintenance therapy was well-tolerated and noninferior to lansoprazole f

关键词： Erosive esophagitis Lansoprazole Maintenance therapy Potassium-competitive acid blockers Vonoprazan

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Cobalt-Catalyzed Switchable[4+1]and[4+1+1]Spirocyclization of Aromatic Amides with 2-Diazo-1H-indene-1,3(2H)-dione:Access to Spiro Indene-2,1'-isoindolinones and Spiro Isochroman-3,1'-isoindolinones

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Chinese Journal of Chemistry 2024年第4期42卷 363-369页

作者： Bin li Mengmeng xie Jingyu li Nana Shen Xinying Zhang Xuesen Fan State Key Laboratory of Antiviral Drugs Pingyuan LaboratoryKey Laboratory of Green Chemical Media and ReactionsKey Laboratory for Yellow River and Huai River Water Environmental Pollution ControlMinistry of EducationSchool of EnvironmentSchool of Chemistry and Chemical EngineeringHenan Normal UniversityXinxiangHenan453007 China

Herein,we report a condition-controlled divergent synthesis of spiro indene-2,1'-isoindolinones and spiro isochroman-3,1'-isoindolinones through cobalt-catalyzed formal[4+1]and[4+1+1]spirocyclization of aromatic amides with 2-diazo-1H-indene-1,3(2H)-dione.When the reaction is carried out under air in ethyl acetate,spiro indene-2,1'-isoindolinones are formed through Co(II)-catalyzed C—H/N—H[4+1]spirocyclization.When the reaction is run under O2 in CH3CN,on the other hand,spiro isochroman-3,1'-isoindolinones are generated through Baeyer-Villiger oxidation of the in situ formed spiro indene-2,1'-isoindolinones with O2 as a cheaper and environmental-friendly oxygen source.In general,these protocols have advantages such as using non-precious and earth-abundant metal catalyst,no extra additive,high efficiency and regioselectivity.A gram-scale synthesis and the removal of the directing group further highlight its utility.

关键词： Spiro indene-2,1'-isoindolinones Spiro isochroman-3,1'-isoindolinones 3d Transition metals Cobalt-catalyzed C-H Activation Switchable[4+1]and[4+1+1]spirocyclization Aromatic amides 2-Diazo-1H-indene-1,3(2H)-dione

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Heralded entanglement between error-protected logical qubits for fault-tolerant distributed quantum computing

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 25-33页

作者： Jialun li Zhihao xie Yachen li Yansen liang Zhenhua li Tao li MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing School of PhysicsNanjing University of Science and TechnologyNanjing 210094China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

Quantum error correction is essential for achieving reliable quantum information processing tasks,as it can mitigate the detrimental effects of noise by encoding single-qubit information into a larger quantum system.However,the generation of distributed entanglement between logical qubits located within two spatially separated nodes presents a significant resource-intensive challenge that has yet to be overcome.Here we present a heralded protocol for generating distributed entanglement between two nonlocal error-protected logical qubits.A high-dimensional single photon can evolve physical qubits into a logical qubit that entangles with the photon and then converts logical qubit-photon entanglement into entanglement between two logical qubits,when the photon state is properly tuned and an effective photon-spin interface between single photons and individual spins is exploited.Furthermore,the success of the entanglement generation is heralded by the detection of the photon,and the corresponding efficiency can,in principle,approach unity.These distinguished features make our protocol highly appealing for future large-scale quantum technologies.

关键词： quantum networks distributed entanglement error-protected logical qubits high-dimensional photons

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Visible-light-Promoted Palladium-Catalyzed Cross-Coupling of lodocarboranes with Disulfides and Phenylselenyl Chloride

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Chinese Journal of Chemistry 2024年第2期42卷 129-134页

作者： Shimeng li Yizhen liu Zuowei xie Shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and TechnologyShenzhenGuangdong 518055China

This work describes a general method for the synthesis of a series of sulfenylated and selenylated carboranes at room temperature using readily available iodocarboranes as starting materials via boron-centered carboranyl radicals.Such hypervalent boron radicals are generated by a visible-light-promoted Pd(O)/Pd(I)pathway.They are useful intermediates and can be trapped by disulfides and phenylselenyl chloride for the convenient construction of B-S/Sebonds.

关键词： Carborane Sulfenylation Selenylation B-I activation Radical Photocatalysis Boron Selectivity

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Recent progress in visualization and digitization of coherent transformation structures and application in high-strength steel

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1298-1310页

作者： Xuelin Wang Zhenjia xie Xiucheng li Chengjia Shang Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Yangjiang Branch Guangdong Laboratory for Materials Science and Technology(Yangjiang Advanced Alloys Laboratory)Yangjiang 529500China

High-strength steels are mainly composed of medium-or low-temperature microstructures,such as bainite or martensite,with coherent transformation characteristics.This type of microstructure has a high density of dislocations and fine crystallographic structural units,which ease the coordinated matching of high strength,toughness,and plasticity.Meanwhile,given its excellent welding perform-ance,high-strength steel has been widely used in major engineering constructions,such as pipelines,ships,and bridges.However,visual-ization and digitization of the effective units of these coherent transformation structures using traditional methods(optical microscopy and scanning electron microscopy)is difficult due to their complex morphology.Moreover,the establishment of quantitative relationships with macroscopic mechanical properties and key process parameters presents additional difficulty.This article reviews the latest progress in microstructural visualization and digitization of high-strength steel,with a focus on the application of crystallographic methods in the development of high-strength steel plates and welding.We obtained the crystallographic data(Euler angle)of the transformed microstruc-tures through electron back-scattering diffraction and combined them with the calculation of inverse transformation from bainite or martensite to austenite to determine the reconstruction of high-temperature parent austenite and orientation relationship(OR)during con-tinuous cooling transformation.Furthermore,visualization of crystallographic packets,blocks,and variants based on actual OR and digit-ization of various grain boundaries can be effectively completed to establish quantitative relationships with alloy composition and key process parameters,thereby providing reverse design guidance for the development of high-strength steel.

关键词： high-strength steel microstructure visualization digitization quantification mechanical properties

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Investigation on the influence of vortex generator on particle resuspension

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Particuology 2024年第3期86卷 126-136页

作者： Dongchi Yu Jun-li lin Jin-Han xie ASML 80W Tasman DrSan Jose95134CaliforniaUSA Department of Mechanics and Engineering Science at College of Engineering and State Key Laboratory for Turbulence and Complex Systems Peking UniversityBeijing100081China

The vortex generator(VG)and its well-known effect in flow optimization are widely studied and employed across different engineering sectors.However,while the same working principles of VG may be well suited for the applications on surface-cleaning technologies,such promising potential is hardly,if any,explored in the published literature.Therefore,in the present study,the influence on flow-induced particle resuspension brought by a rectangular vG in a channel flow is investigated with the help of highfidelity computational fluid dynamics simulations.Substantial increases of particle removal forces and resuspension rates are discovered in long,strip-like regions with reduced boundary-layer thickness resulted from the vG-induced vortices,and the enhancement effect is especially significant for configurations with the VG installed at a greater angle of attack.It is also shown that while the resuspension enhancements on the lower and the upper surfaces of the channel exhibit distinct statistical characteristics,having a VG in the channel improves the overall particle-removing capability of the channel flow by introducing higher surface-averaged removal forces and particle resuspension rates.Last but not least,the increase of resuspension rate is especially significant for the smaller,micron-scale particles which are otherwise hardly disturbed by a VG-less channel flow,and such resuspension-enhancement effectgenerally subsides with increasing particle size.

关键词： Particle resuspension Vortexgenerator CFD Surface cleaning

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Event-triggered finite-time command-filtered tracking control for nonlinear time-delay cyber physical systems against cyber attacks

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Frontiers of Information Technology & Electronic Engineering 2024年第2期25卷 225-236页

作者： Yajing MA Yuan WANG Zhanjie li Xiangpeng xie School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing210003China Institute of Advanced Technology for Carbon NeutralityNanjing University of Posts and TelecommunicationsNanjing210023China

This article addresses the secure finite-time tracking problem via event-triggered command-filtered control for nonlinear time-delay cyber physical systems(CPSs)subject to cyber attacks.Under the attack circumstance,the output and state information of CPSs is unavailable for the feedback design,and the classical coordinate conversion of the iterative process is incompetent in relation to the tracking task.To solve this,a new coordinate conversion is proposed by considering the attack gains and the reference signal simultaneously.By employing the transformed variables,a modified fractional-order command-filtered signal is incorporated to overcome the complexity explosion issue,and the Nussbaum function is used to tackle the varying attack gains.By systematically constructing the Lyapunov-Krasovskii functional,an adaptive event-triggered mechanism is presented in detail,with which the communication resources are greatly saved,and the finite-time tracking of CPSs under cyber attacks is guaranteed.Finally,an example demonstrates the effectiveness.

关键词： Cyber physical systems Finite-time tracking Event-triggered Command-filtered control Attacks

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Enhanced properties of stone coal-based composite phase change materials for thermal energy storage

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 206-215页

作者： Baoshan xie Huan Ma Chuanchang li Jian Chen Key Laboratory of Renewable Energy Electric-Technology of Hunan Province School of Energy and Power EngineeringChangsha University of Science and TechnologyChangsha 410114China State Key Laboratory of Disaster Prevention and Reduction for Power Grid Changsha University of Science and TechnologyChangsha 410114China

Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications.Stone coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite preparation.We prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an additive.The combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading capacity.Results showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface area.The loading capacity and thermal conductivity of the composite obviously increased by 127%and 48.19%,respectively,due to the contribution of 3wt% EG.These data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1)·K-1of the designed composite.The obtained composite exhibited a phase change temperature of 52.17℃,melting latent heat of 121.5 J·g^(-1),and good chemical compatibility.The SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.

关键词： thermal energy storage phase change material stone coal vanadium extraction secondary utilization

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Customer Joining Behavior and Regulation Strategy in Visible Multi-Server Queues with Synchronous Vacations of Partial Servers

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Journal of Systems Science & Complexity 2024年第3期37卷 1209-1232页

作者： SUN Wei WANG Hao xie Xumeng li Shiyong School of Economics and Management Yanshan UniversityQinhuangdao 066004China

This paper studies customer joining behavior and system regulation strategy in nonexhaustive visible M/M/m queues with synchronous vacations of a part of the servers.Once this part of the servers are idle,they take multiple vacations simultaneously(vacation period).Until there are customers waiting in the queue,they are reactivated and all servers are busy or idle(busy period).The authors call this part of the servers as“partial servers”.In view of the fully visible queue and the almost visible queue,the authors obtain customers’equilibrium joining threshold strategies and their socially optimal joining threshold strategies,respectively,and observe that customer joining behavior in equilibrium generally makes the system overcrowded,which makes the equilibrium social welfare lower than the optimal social welfare.After regulation,interestingly,for optimizing social welfare,the system manager hopes not only customers arriving in vacation period pay attention to the number of partial servers,but also customers arriving in busy period should care about it rather than ignore.Moreover,arranging more servers for vacation does not necessarily lead to the decrease of social welfare on condition that the number of partial servers is close to m.As for the information advantage of the fully visible case,it is not obvious for increasing social welfare and even unfavorable to servers’profit unless the number of partial servers is big enough.Furthermore,given the different composition of social welfare,there exists the optimal number of partial servers and the optimal arrival rate of customers for maximizing social welfare.

关键词： Customer behavior non-exhaustive service partial servers regulation strategy synchronous vacations visible queue

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