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Frontiers of Chemical Science and Engineering 2023年第10期17卷 1516-1532页

作者： Lifeng Zhang Haoyang Hu Zhiquan WANG Zhihong Yuan Bingzhen Chen State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Department of Chemical Engineering Tsinghua UniversityBeijing 100084China

This paper focuses on the integrated problem of long-term planning and short-term scheduling in a largescale refinery-petrochemical complex,and considers the overall manufacturing process from the upstream refinery to the downstream petrochemical site.Different time scales are incorporated from the planning and scheduling subproblems.At the end of each discrete time period,additional constraints are imposed to ensure material balance between different time scales.Discrete time representation is applied to the planning subproblem,while continuous time is applied to the scheduling of ethylene cracking and polymerization processes in the petrochemical site.An enterprise-wide mathematical model is formulated through mixed integer nonlinear programming.To solve the problem efficiently,a heuristic algorithm combined with a convolutional neural network(CNN),is proposed.Binary variables are used as the CNN input,leading to the integration of a data-driven approach and classical optimization by which a heuristic algorithm is established.The results do not only illustrate the detailed operations in a refinery and petrochemical complex under planning and scheduling,but also confirm the high efficiency of the proposed algorithm for solving large-scale problems.

关键词： planning scheduling refinery-petrochemical convolutional neural network heuristic algorithm

Data-driven optimal operation of the industrial methanol to olefin process based on relevance vector machine

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Chinese Journal of Chemical Engineering 2021年第6期34卷 106-115页

作者： Zhiquan WANG Liang wang Zhihong Yuan Bingzhen Chen Department of Chemical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

Methanol to olefin(MTO)technology provides the opportunity to produce olefins from nonpetroleum sources such as coal,biomass and natural gas.More than 20 commercial MTO plants have been put into operation.Till now,contributions on optimal operation of industrial MTO plants from a process systems engineering perspective are rare.Based on relevance vector machine(RVM),a data-driven framework for optimal operation of the industrial MTO process is established to fully utilize the plentiful industrial data sets.RVM correlates the yield distribution prediction of main products and the operation conditions.These correlations then serve as the constraints for the multi-objective optimization model to pursue the optimal operation of the plant.Nondominated sorting genetic algorithmⅡis used to solve the optimization problem.Comprehensive tests demonstrate that the ethylene yield is effectively improved based on the proposed framework.Since RVM does provide the distribution prediction instead of point estimation,the established model is expected to provide guidance for actual production operations under uncertainty.

关键词： Methanol to olefins Relevance vector machine Genetic algorithm Operation optimization Systems engineering Process systems

Joining of Co coated ferritic stainless steel to ceramic solid oxide cells by a novel Ag-SiO_(2) braze

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Journal of Materials Science & Technology 2022年第26期121卷 174-180页

作者： Zhiquan WANG Chun Li Ragnar Kiebach Ilaria Ritucci Ming Chen Jian Cao State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Department of Energy Conversion and Storage Technical University of DenmarkLyngby CampusAnker Engelunds Vej2800Denmark

A novel Ag-SiO_(2) braze for Solid Oxide Cells was successfully developed and applied to join Co coated AISI 441 ferritic stainless steel to YSZ-NiO half cells.The braze showed an improved wettability on the coated steel and the YSZ compared to pure Ag.A defect-free steel/YSZ joint was obtained using an Ag-1SiO_(2) braze jointed at 1000℃for 30 min in air.The microstructure of the joints was characterized by scanning electron microscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopy.Furthermore,a Co-Si-O_(2)phase diagram was calculated and used to explain the experimental results and formulate a reaction mechanism.It was found,that during the air brazing process,Co_(3)O_(4)and(Co,Fe)_(3)O_(4)are formed by the oxidation of the prefabricated Co coating.The growth of Cr_(2)O_(3)was effectively impeded by the formed Co-based spinels.In a second step,Co_(2)O_(3)reacts with the SiOpresent in braze.The CoSiOformed by the reaction ensures a firm bonding between the steel and Ag-SiObraze.

关键词： Co coated stainless steel YSZ-NiO half cell Microstructure Interfacial reaction Joining Ag-SiO_(2)braze Solid Oxide Cells

Research on Magnetically Coupled Resonant Detection Method for Breakpoint of Four Mesh Grounding Grid

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CES Transactions on Electrical Machines and Systems 2023年第2期7卷 218-228页

作者： Weihua Chen Shuai wang Xiaoheng Yan zhiquan Ye the School of Liaoning Technical University(Huludao) Liaoning Huludao125100China

Magnetically coupled resonant technology is a novel method for solving the breakpoint locating of power grounding grid.But the method can only detect breakpoints of a single mesh grounding grid at present.In this paper,a magnetically coupled resonant detection method for four-hole grounding grid breakpoint is proposed.Firstly,the equivalent circuit model of the four mesh grounding grid with two types of breakpoints,namely edge branch and intermediate branch,is established.The input impedance and phase angle of the system are obtained by analyzing the equivalent capacitance and equivalent resistance in the model.Secondly,the magnetically coupled resonant physical process of grounding grid faults is solved via HFSS software.The magnetic field intensity and phase frequency characteristic curves of four mesh holes with different branches and positions of breakpoints and different corrosion degrees are studied,and an experimental system is built to verify the feasibility.The results show that under the condition of grounding grid buried depth of 0.5 m and input frequency of 1~15MHz,and there is an inverse relationship between equivalent capacitance and distortion frequency,the phase angle is positively correlated with the degree of corrosion of grounding grid,and the error of signal distortion frequency can be positioned at 5%.This paper provides some ideas for the application of magnetic coupling grounding grid detection technology.

关键词： Grounding grid Magnetically coupled resonant detection Input impedance Phase frequency characteristic curve

Unraveling the Effects of Austenitizing Temperature and Austenite Grain Size on the Crystallographic Characteristics and Mechanical Properties of Martensitic Transformation Products in a Low‑Alloy Steel

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Acta Metallurgica Sinica(English Letters) 2023年第4期36卷 694-704页

作者： Binbin Wu Fangzhong Hu Zhiquan WANG Shaopeng Yang Rui Zhong Chengjia Shang Zhigang Yang Chi Zhang Key Laboratory for Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Technical Center Masteel Co.Ltd.Ma’anshan 243000China Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China Yangjiang Branch Guangdong Laboratory for Materials Science and Technology(Yangjiang Advanced Alloys Laboratory)Yangjiang 529500China

The influence of austenitizing temperature and austenite grain size on the crystallographic characteristics and mechanical properties of transformation products was investigated in a low-alloy steel.Annealing at a lower temperature after austenitization at 1050℃ can reduce the vacancy concentration and enhance the stability of austenite,thereby determining the martensite-start(Ms)temperature and density of twin-related V1/V2 variant pairs.V1/V2 variant pairs are predominately generated by autocatalytic nucleation,which can promote transformation by self-accommodation.Annealing at 800℃ after austenitization at 1050℃ generated the highest content of V1/V2 variant pairs,which contributed to high values of strength,Charpy impact energy,and elongation.In addition to refining the austenite grain size,niobium(Nb)microalloying increases the packet boundaries of the transformation products,mainly because the refined austenite grains provide more nucleation sites for the martensitic transformation.However,the density of block boundaries decreases after austenite refinement by Nb microalloying,owing to insufficient autocatalytic nucleation.

关键词： Steel Martensite Transformation Nucleation Variant

A Lamb wave signal reconstruction method for high-resolution damage imaging

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Chinese Journal of Aeronautics 2019年第5期32卷 1087-1099页

作者： Xiaopeng wang Jian CAI zhiquan ZHOU State Key Lab of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics

In Lamb wave-based Structural Health Monitoring(SHM), a high-enough spatial resolution is highly required for Lamb wave signals to ensure the resolution and accuracy of damage detection. However, besides the dispersion characteristic, the signal spatial resolution is also largely restricted by the space duration of excitation waveforms, i.e., the Initial Spatial Resolution(ISR)for the signals before travelling. To resolve the problem of inferior signal spatial resolution of Lamb waves, a Lamb Wave Signal Reconstruction(LWSR) method is presented and applied for highresolution damage imaging in this paper. In LWSR, not only a new linearly-dispersive signal is reconstructed from an original Lamb wave signal, but also the group velocity at the central frequency is sufficiently decreased. Then, both dispersion compensation and ISR improvement can be realized to achieve a satisfying signal spatial resolution. After the frequency domain sensing model and spatial resolution of Lamb wave signals are firstly analyzed, the basic idea and numerical realization of LWSR are discussed. Numerical simulations are also implemented to preliminarily validate LWSR. Subsequently, LWSR-based high-resolution damage imaging is developed. An experiment of adjacent multiple damage identification is finally conducted to demonstrate the efficiency of LWSR and LWSR-based imaging methods.

关键词： Damage imaging Dispersion compensation High resolution Lamb waves Signal reconstruction

Biomass chemical looping gasification for syngas production using modified hematite as oxygen carriers

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Journal of Environmental Sciences 2023年第3期125卷 171-184页

作者： Cong Jiang Xiaoyu Jin Tingting Xu Bo Xiao zhiquan Hu Xun wang School of Environmental Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Coal Combustion Huazhong University of Science and TechnologyWuhan 430074China

Syngas is a clean energy carrier and a major industrial feedstock. In this paper, syngas was produced via biomass chemical looping gasification(CLG) process. Hematite, the most common Fe-based oxygen carrier(OC), was modified with different metal oxides(CeO_(2), CaO and MgO) by the impregnation method. The hematite modified by CeO_(2), CaO and MgO was namely as CeO_(2)-hematite(CeO_(2)-H), CaO-hematite(CaO-H) and MgO-hematite(MgO-H), respectively. The introduction of CeO_(2), CaO and MgO enhanced the reactivity of lattice oxygen of hematite. The optimum condition for syngas production had been explored as the mass ratio of oxygen carrier to biomass(O/B) of 0.2, the mass ratio of steam to biomass(S/B) of0.75 and temperature of 800℃in the biomass CLG process. The CeO_(2)-H exhibited the most wonderful performance compared to that for CaO-H and MgO-H. The crystal composition of OC influenced greatly in the CLG process. CeFeO_(3)had a good oxygen mobility property and lattice oxygen releasing capacity due to the most oxygen vacancy distributed on the OC surface and the most active lattice oxygen, which is conducive to the biomass chemical looping gasification process for syngas production, leading to the highest gasification efficiency of 95.86% and gas yield of 1.20 m^(3)/kg of the three. Cyclic test proved that CeO_(2)-H had well sintering resistance and cyclic performance.

关键词： Chemical looping gasification Oxygen carrier Syngas Modified hematite Pine sawdust

Association of blood pressure variability with target organ damage in older patients with essential hypertension

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Chronic Diseases and Translational Medicine 2023年第4期9卷 320-328页

作者： zhiquan Jing Gang wang Zeya Li Shanshan Wu Xiang Qiu Rongchong Huang Department of Cardiology Beijing Friendship HospitalCapital Medical UniversityBeijingChina Department of Clinical Epidemiology and EBM Beijing Friendship HospitalCapital Medical UniversityBeijingChina Department of Cardiology Beijing Fangshan First HospitalBeijingChina

Background:Although multiple measures of blood pressure variability(BPV)have been proposed,whether they are better than mean blood pressure in predicting target organs is unclear.We aimed to determine the relationship between short term BPV and target organ injury.Methods:This study was a retrospective study,and 635 inpatients in the Department of Cardiology from 2015 to 2020 were selected.We divided participants into four groups on the basis of the quartiles of BPV.One-way analysis of variance was used to compare the differences between the groups,and linear regression was used to analyze the relationship between BPV and target organ damage.Results:The average age of 635 patients was 74.36±6.50 years old.Among them,354 of 627 patients had diminished renal function(56.5%),221of 604 patients had associated left ventricular hypertrophy(36.6%),and 227 of 231 patients had carotid plaque formation(98.3%).The baseline data indicated significant differences in fasting glucose,total cholesterol,low-density lipoprotein,creatinine,glomerular filtration rate,sex,calcium channel blocker use,and the rate of diminished renal function.Multiple linear regression analysis showed that BPV was negatively correlated with renal injury(creatinine:r=0.306,p<0.01;estimated glomerular filtration rate:r=0.058,p<0.01),and BPV is positively correlated with cardiac injury(r=0.083,p<0.01).Elevated BPV was not found to be associated with vascularinjury.Conclusion:Renal function decreases with increasing BPV and left ventricular mass increases with increasing BPV.

关键词： ambulatory blood pressure monitoring blood pressure variability hypertension target organ damage

Decreased serum albumin level indicates poor prognosis of COVID-19 patients: hepatic injury analysis from 2,623 hospitalized cases

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Science China(Life Sciences) 2020年第11期63卷 1678-1687页

作者： Wei Huang Chenze Li Zhiquan WANG Hong wang Ning Zhou Jiangang Jiang Li Ni Xin A.Zhang Dao-Wen wang Division of Cardiology Department of Internal Medicineand Hubei Key Laboratory of Genetics and Molecular Mechanisms of Cardiological DisordersTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430010China Department of Cardiology Chinese PLA Central War Command General HospitalWuhan 430010China Stephenson Cancer Center and Department of Physiology University of Oklahoma Health Sciences CenterOklahoma CityOK 73104USA

Coronavirus disease 2019(COVID-19) is a global pandemic which has caused numerous deaths worldwide. The present study investigated the roles of hypoproteinemia in the clinical outcome and liver dysfunction of COVID-19 patients. In this retrospective study, we extracted data from 2,623 clinically confirmed adult COVID-19 patients(≥18 years old) between January 29,2020 and March 6, 2020 in Tongji Hospital, Wuhan, China. The patients were divided into three groups—non-critically ill,critically ill, and death groups—in accordance with the Chinese Clinical Guideline for COVID-19. Serum albumin, low-density lipoproteins cholesterol(LDL-C), and high-density lipoproteins cholesterol(HDL-C) concentrations and inflammatory cytokines levels were measured and compared among these three groups. The median age of these 2,623 patients was 64 years old(interquartile range(IQR), 52–71). Among the patients enrolled in the study, 2,008(76.6%) were diagnosed as non-critically ill and 615(23.4%) were critically ill patients, including 383(14.6%) critically ill survivors and 232(8.8%) critically ill deaths in the hospital. Marked hypoalbuminemia occurred in 38.2%, 71.2%, and 82.4% patients in non-critically ill, critically ill, and death groups, respectively, on admission and 45.9%, 77.7%, and 95.6% of these three groups, respectively, during hospitalization. We also discovered that serum low-density lipoprotein(LDL) and HDL levels were significantly lower in critically ill and death groups compared to non-critically ill group. Meanwhile, the patients displayed dramatically elevated levels of serum inflammatory factors, while a markedly prolonged activated partial thromboplastin time(APTT) in critically ill patients reflected coagulopathy. This study suggests that COVID-19-induced cytokine storm causes hepatotoxicity and subsequently critical hypoalbuminemia, which are associated with exacerbation of disease-associated inflammatory responses and progression of the disease and ultimately leads to death for some critically ill patients.

关键词： albumin hepatic injury COVID-19

Research on robust mean square stability of networked control systems with packet dropout

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Journal of Systems Engineering and Electronics 2010年第1期21卷 95-101页

作者： Dexiao Xie Xiaodong Han He Huang Zhiquan WANG School of Automation Nanjing University of Science and Technology Nanjing 210094 P. R. China Beijing Institute of Satellite Information Engineering China Academy of Space Technology Beijing 100094 E R. China

This paper is concerned with the robust stabilization problem of networked control systems with stochastic packet dropouts and uncertain parameters. Considering the stochastic packet dropout occuring in two channels between the sensor and the controller, and between the controller and the actuator, networked control systems are modeled as the Markovian jump linear system with four operation modes. Based on this model, the necessary and sufficient conditions for the mean square stability of the deterministic networked control systems and uncertain networked control systems are given by using the theory of the Markovian jump linear system, and corresponding controller design procedures are proposed via the cone complementarity linearization method. Finally, the numerical example and simulations are given to illustrate the effectiveness of the proposed results.

关键词： networked control system packet dropout meansquare stability Markovian jump linear system.