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U-model Enhanced Dynamic Control of a Heavy Oil Pyrolysis/Cracking Furnace 被引量:1
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作者 Quanmin Zhu Dongya Zhao +1 位作者 Shuzhan Zhang Pritesh Narayan 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第2期577-586,共10页
This paper proposes a case study in the control of a heavy oil pyrolysis/cracking furnace with a newly extended U-model based pole placement controller(U-PPC). The major work of the paper includes: 1) establishing a c... This paper proposes a case study in the control of a heavy oil pyrolysis/cracking furnace with a newly extended U-model based pole placement controller(U-PPC). The major work of the paper includes: 1) establishing a control oriented nonlinear dynamic model with Naphtha cracking and thermal dynamics; 2) analysing a U-model(i.e., control oriented prototype) representation of various popular process model sets; 3)designing the new U-PPC to enhance the control performance in pole placement and stabilisation; 4) taking computational bench tests to demonstrate the control system design and performance with a user-friendly step by step procedure. 展开更多
关键词 Index Terms-Computational experiments heavy oil crackingfurnace Kumar molecular dynamics model for Naphtha crack-ing pole placement controller stabilising controller U-model U-model enhanced controller design.
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Impact of climate change and human activities on the spatiotemporal dynamics of surface water area in Gansu Province, China
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作者 LU Haitian ZHAO Ruifeng +3 位作者 ZHAO Liu LIU Jiaxin LYU Binyang YANG Xinyue 《Journal of Arid Land》 SCIE CSCD 2024年第6期798-815,共18页
Understanding the dynamics of surface water area and their drivers is crucial for human survival and ecosystem stability in inland arid and semi-arid areas.This study took Gansu Province,China,a typical area with comp... Understanding the dynamics of surface water area and their drivers is crucial for human survival and ecosystem stability in inland arid and semi-arid areas.This study took Gansu Province,China,a typical area with complex terrain and variable climate,as the research subject.Based on Google Earth Engine,we used Landsat data and the Open-surface Water Detection Method with Enhanced Impurity Control method to monitor the spatiotemporal dynamics of surface water area in Gansu Province from 1985 to 2022,and quantitatively analyzed the main causes of regional differences in surface water area.The findings revealed that surface water area in Gansu Province expanded by 406.88 km2 from 1985 to 2022.Seasonal surface water area exhibited significant fluctuations,while permanent surface water area showed a steady increase.Notably,terrestrial water storage exhibited a trend of first decreasing and then increasing,correlated with the dynamics of surface water area.Climate change and human activities jointly affected surface hydrological processes,with the impact of climate change being slightly higher than that of human activities.Spatially,climate change affected the'source'of surface water to a greater extent,while human activities tended to affect the'destination'of surface water.Challenges of surface water resources faced by inland arid and semi-arid areas like Gansu Province are multifaceted.Therefore,we summarized the surface hydrology patterns typical in inland arid and semi-arid areas and tailored surface water'supply-demand'balance strategies.The study not only sheds light on the dynamics of surface water area in Gansu Province,but also offers valuable insights for ecological protection and surface water resource management in inland arid and semi-arid areas facing water scarcity. 展开更多
关键词 surface water area terrestrial water storage Open-surface Water Detection Method with enhanced Impurity Control method Google Earth Engine climate change human activities inland arid and semi-arid areas
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Mechanism of Electromagnetic Flow Control Enhanced by Electro-Discharge in Water
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作者 Yan-Liang Ji Ben-Mou Zhou Ya-Dong Huang 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第5期73-77,共5页
Pulsed discharge utilized to achieve large current density in the electromagnetic flow control is numerically studied. A mathematic discharge model is established to calculate the plasma channel, and an actuator is de... Pulsed discharge utilized to achieve large current density in the electromagnetic flow control is numerically studied. A mathematic discharge model is established to calculate the plasma channel, and an actuator is designed to generate the Lorentz force in the micro plasma channel. During the discharge process, the resistance in the channel decreases rapidly and a large current density appears between the discharge electrodes. After the actuator is applied in the leading edge of a flat plate, the separation region and downstream turbulent boundary layer on the plate disappear. Meanwhile, a skin-friction drag force reduction is achieved. 展开更多
关键词 Mechanism of Electromagnetic Flow Control enhanced by Electro-Discharge in Water
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CO_2-triggered gelation for mobility control and channeling blocking during CO_2 flooding processes 被引量:7
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作者 De-Xiang Li Liang Zhang +2 位作者 Yan-Min Liu Wan-Li Kang Shao-Ran Ren 《Petroleum Science》 SCIE CAS CSCD 2016年第2期247-258,共12页
CO2 flooding is regarded as an important method for enhanced oil recovery (EOR) and greenhouse gas control. However, the heterogeneity prevalently dis- tributed in reservoirs inhibits the performance of this technol... CO2 flooding is regarded as an important method for enhanced oil recovery (EOR) and greenhouse gas control. However, the heterogeneity prevalently dis- tributed in reservoirs inhibits the performance of this technology. The sweep efficiency can be significantly reduced especially in the presence of "thief zones". Hence, gas channeling blocking and mobility control are important technical issues for the success of CO2 injection. Normally, crosslinked gels have the potential to block gas channels, but the gelation time control poses challenges to this method. In this study, a new method for selectively blocking CO2 channeling is proposed, which is based on a type of CO2-sensitive gel system (modified polyacry- lamide-methenamine-resorcinol gel system) to form gel in situ. A CO2-sensitive gel system is when gelation or solidification will be triggered by CO2 in the reservoir to block gas channels. The CO2-sensitivity of the gel system was demonstrated in parallel bottle tests of gel in N2 and CO2 atmospheres. Sand pack flow experiments were con- ducted to investigate the shutoff capacity of the gel system under different conditions. The injectivity of the gel system was studied via viscosity measurements. The results indi- cate that this gel system was sensitive to CO2 and had good performance of channeling blocking in porous media. Advantageous viscosity-temperature characteristics were achieved in this work. The effectiveness for EOR in heterogeneous formations based on this gel system was demonstrated using displacement tests conducted in double sand packs. The experimental results can provide guideli- nes for the deployment of theCO2-sensitive gel system for field applications. 展开更多
关键词 CO2 flooding Gas channeling - CO2sensitivity - Sweep efficiency enhanced oil recoveryMobility control
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A General Framework of Reversible Data Hiding with Controlled Contrast Enhancement
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作者 Shaowei Weng Yiyun Liu +3 位作者 Yunqing Shi Bo Ou Chunyu Zhang Cuiping Wang 《Computers, Materials & Continua》 SCIE EI 2020年第1期157-177,共21页
This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast enhancement.The first step aims at preserving visual perception as much as possible on the basis of ac... This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast enhancement.The first step aims at preserving visual perception as much as possible on the basis of achieving high embedding capacity(EC),while the second step is used for increasing image contrast.In the second step,some peak-pairs are utilized so that the histogram of pixel values is modified to perform histogram equalization(HE),which would lead to the image contrast enhancement.However,for HE,the utilization of some peak-pairs easily leads to over-enhanced image contrast when a large number of bits are embedded.Therefore,in our proposed framework,contrast over-enhancement is avoided by controlling the degree of contrast enhancement.Since the second step can only provide a small amount of data due to controlled contrast enhancement,the first one helps to achieve a large amount of data without degrading visual quality.Any RDH method which can achieve high EC while preserve good visual quality,can be selected for the first step.In fact,Gao et al.’s method is a special case of our proposed framework.In addition,two simple and commonly-used RDH methods are also introduced to further demonstrate the generalization of our framework. 展开更多
关键词 Reversible data hiding controlled contrast enhancement general framework PEE-based RDH method IT-based RDH method
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Ultralow-noise single-photon detection based on precise temperature controlled photomultiplier with enhanced electromagnetic shielding 被引量:1
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作者 Mingyu Wang Zhengyong Li +4 位作者 Yanhui Cai Yi Zhang Xiangkong Zhan Haiyang Wang Chongqing Wu 《Chinese Optics Letters》 SCIE EI CAS CSCD 2017年第10期7-10,共4页
We demonstrate an ultralow-noise single-photon detection system based on a sensitive photomultiplier tube(PMT) with precise temperature control, which can capture fast single photons with intervals around 10 ns.By i... We demonstrate an ultralow-noise single-photon detection system based on a sensitive photomultiplier tube(PMT) with precise temperature control, which can capture fast single photons with intervals around 10 ns.By improvement of the electromagnetic shielding and introduction of the self-differencing method, the dark counts(DCs) are cut down to ~1%. We further develop an ultra-stable PMT cooling subsystem and observe that the DC goes down by a factor of 3.9 each time the temperature drops 10°C. At -20°C it is reduced 400 times with respect to the room temperature(25°C), that is, it becomes only 2 counts per second, which is on par with the superconducting nanowire detectors. Meanwhile, despite a 50% loss, the detection efficiency is still 13%. Our detector is available for ultra-precise single-photon detection in environments with strong electromagnetic disturbances. 展开更多
关键词 PMT Ultralow-noise single-photon detection based on precise temperature controlled photomultiplier with enhanced electromagnetic shielding
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Comparison of Space Glucose Control and Routine Glucose Management Protocol for Glycemic Control in Critically Ⅲ Patients: A Prospective, Randomized Clinical Study 被引量:4
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作者 Biao Xu Wei Jiang +4 位作者 Chun-Yao Wang Li Weng Xiao-Yun Hu Jin-Min Peng Bin Du 《Chinese Medical Journal》 SCIE CAS CSCD 2017年第17期2041-2049,共9页
Background:The Space Glucose Control (SGC) system is a computer-assisted device combining infusion pumps with the enhanced Model Predictive Control algorithm to achieve the target blood glucose (BG) level safely.... Background:The Space Glucose Control (SGC) system is a computer-assisted device combining infusion pumps with the enhanced Model Predictive Control algorithm to achieve the target blood glucose (BG) level safely.The objective of this study was to evaluate the efficacy and safety of glycemic control by SGC with customized BG target range of 5.8-8.9 mmol/L in the critically ill patients.Methods:It is a randomized controlled trial of seventy critically ill patients with mechanical ventilation and hyperglycemia (BG 〉 9.0 mmol/L).Thirty-six patients in the SGC group and 34 in the routine glucose management group were observed for three consecutive days.Target BG for both groups was 5.8-8.9 mmol/L.The primary outcome was the percentage time in the target range.Results:The percentage time within BG target range in the SGC group (69 &#177; 15%) was significantly higher than in the routine management group (52 &#177; 24%;P 〈 0.01).No measurement was 〈2.2 mmol/L,and there was only one episode of hypoglycemia (2.3-3.3 mmol/L) in each group.The average BG was significantly lower in the SGC group (7.8 &#177; 0.7 mmol/L) than in the routine management group (9.1 &#177; 1.6 mmol/L,P 〈 0.001).Target BG level was reached earlier in the SGC group than routine management group (2.5 &#177; 2.9 vs.12.1 &#177; 15.3 h,P =0.001).However,the SGC group performed worse for daily insulin requirement (59.8 &#177; 39.3 vs.28.4 &#177; 36.7 U,P =0.001)and sampling interval (2.0 &#177; 0.5 vs.3.7 &#177; 0.5 h,P 〈 0.001) than the routine management group did.Multiple linear regression showed that the intervention group remained a significant individual predictor (P 〈 0.001) of the percentage time in target range.Conclusions:The SGC system,with a BG target of 5.8-8.9 mmol/L,resulted in effective and reliable glycemic control with few hypoglycemic episodes in critically ill patients with mechanical ventilation and hyperglycemia.However,the workload was increased.Trial Registration:http://www.clinicaltrials.gov,NCT 02491346;https://www.clinicaltrials.gov/ct2/show/NCT02491346?term=NCT0 2491346&amp;cond=Hyperglycemia&amp;cntry1=ES%3ACN&amp;rank=1. 展开更多
关键词 Critical Illness: Glucose Control in Intensive Care HYPERGLYCEMIA Space Glucose Control enhanced Model Predictive Control
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