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Computational Experiments for Complex Social Systems:Experiment Design and Generative Explanation 被引量:1
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作者 Xiao Xue Deyu Zhou +5 位作者 Xiangning Yu Gang Wang Juanjuan Li Xia Xie Lizhen Cui Fei-Yue Wang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第4期1022-1038,共17页
Powered by advanced information technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).In this context,computational experiments method has emerged as a nove... Powered by advanced information technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).In this context,computational experiments method has emerged as a novel approach for the design,analysis,management,control,and integration of CPSS,which can realize the causal analysis of complex systems by means of“algorithmization”of“counterfactuals”.However,because CPSS involve human and social factors(e.g.,autonomy,initiative,and sociality),it is difficult for traditional design of experiment(DOE)methods to achieve the generative explanation of system emergence.To address this challenge,this paper proposes an integrated approach to the design of computational experiments,incorporating three key modules:1)Descriptive module:Determining the influencing factors and response variables of the system by means of the modeling of an artificial society;2)Interpretative module:Selecting factorial experimental design solution to identify the relationship between influencing factors and macro phenomena;3)Predictive module:Building a meta-model that is equivalent to artificial society to explore its operating laws.Finally,a case study of crowd-sourcing platforms is presented to illustrate the application process and effectiveness of the proposed approach,which can reveal the social impact of algorithmic behavior on“rider race”. 展开更多
关键词 Agent-based modeling computational experiments cyber-physical-social systems(CPSS) generative deduction generative experiments meta model
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Teaching Status and Teaching Reform Ideas of Physical Chemistry Experiments for Food Quality and Safety Major
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作者 Bo HOU Jing LIAO 《Agricultural Biotechnology》 2024年第3期45-47,54,共4页
Physical chemistry experiments are an important branch of chemical experiments.In view of problems and shortcomings in physical chemistry experiment teaching of food quality and safety major in Chengdu University,the ... Physical chemistry experiments are an important branch of chemical experiments.In view of problems and shortcomings in physical chemistry experiment teaching of food quality and safety major in Chengdu University,the teaching methods of physical chemistry experiment course of food quality and safety major were explored and practiced,aiming to arouse students enthusiasm for experiments and cultivate their ability of independent learning,comprehensive thinking and independent problem solving. 展开更多
关键词 Physical chemistry experiment Food quality SAFETY
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Study on the effect and mechanism of Swertia mussotii Franch. in the treatment of primary biliary cholangitis based on bioinformatics and in vitro experiments
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作者 Xing-Fang Zhang Meng-Meng Yang +6 位作者 Yi-Chen Guo Meng-Yuan Wang Hong-Xia Yang Ming Zhang Cen Li Li-Xin Wei Hong-Tao Bi 《Traditional Medicine Research》 2024年第3期32-42,共11页
Background:Primary biliary cholangitis(PBC)is a chronic biliary autoimmune liver disease characterized by intrahepatic cholestasis.Swertia mussotii Franch.(SMF)is a Tibetan medicine with hepatoprotective and anti-infl... Background:Primary biliary cholangitis(PBC)is a chronic biliary autoimmune liver disease characterized by intrahepatic cholestasis.Swertia mussotii Franch.(SMF)is a Tibetan medicine with hepatoprotective and anti-inflammatory activities.In this study,the therapeutic effect and potential mechanisms of SMF on PBC were investigated by bioinformatics analysis and in vitro experimental validation,with the aim of promoting the progress of SMF and PBC research.Methods:We first explored the therapeutic effects and key targets of SMF on PBC using a network pharmacology approach,further screened the core targets using the GSE79850 dataset,and finally validated the results using molecular docking techniques and in vitro experiments.Results:By bioinformatics analysis,we identified core targets of SMF for PBC treatment(STAT3,JAK2,TNF-α,and IL-1β)and important signaling pathways:JAK-STAT,TNF,and PI3K-AKT.The molecular docking results showed that the significant components of SMF had good binding properties to the core targets.In vitro experiments showed that SMF extracts improved the extent of epithelial-mesenchymal transition in human intrahepatic biliary epithelial cells and had a significant reversal effect on epithelial-mesenchymal transition process markers and potential targets in PBC.Conclusion:SMF may exert its therapeutic effects on PBC by acting on important targets such as STAT3,JAK2,TNF-α,IL-1β,Vimentin,and E-cadherin and the pathways in which they are involved. 展开更多
关键词 Swertia mussotii Franch. primary biliary cholangitis BIOINFORMATICS in vitro experiments
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Design and analysis of an advanced thermal management system for the solar close observations and proximity experiments spacecraft
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作者 Liu Liu Kangli Bao +4 位作者 Jianchao Feng Xiaofei Zhu Haoyu Wang Xiaofeng Zhang Jun Lin 《Astronomical Techniques and Instruments》 CSCD 2024年第1期52-61,共10页
In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relat... In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs. 展开更多
关键词 Solar Close Observations and Proximity experiments Adaptive thermal control method Thermal field planning method Pumped liquid cooling system Advanced thermal management system
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Exploration of playa surface crusts in Qehan Lake, China through field investigation and wind tunnel experiments 被引量:1
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作者 LIU Dongwei HAN Lijing +2 位作者 KOU Zihan GAO Xinyu WANG Jingjing 《Journal of Arid Land》 SCIE CSCD 2023年第5期491-507,共17页
Globally,many lakes are drying up,leaving exposed lakebeds where wind erosion releases dust and sand rich in salt and harmful heavy metals into the atmosphere.Therefore,understanding the characteristics and spatial di... Globally,many lakes are drying up,leaving exposed lakebeds where wind erosion releases dust and sand rich in salt and harmful heavy metals into the atmosphere.Therefore,understanding the characteristics and spatial distribution of playa surface crusts is important to recognize the manifestation of salt dust storms.The objective of this study was to explore the playa surface crust types as well as their spatial distribution and evolution of Qehan Lake in Inner Mongolia Autonomous Region,China to understand the salt dust release potential of different types of playa surface crusts.Various crust characteristics were investigated by field sampling in Qehan Lake,and playa surface crusts were further divided into five types:vegetated areas,salt crusts,clay flats,curly crusts,and margins.It should be noted that curly crusts were distributed in clay flats and covered only a small area in Qehan Lake.The spatial distribution characteristics of playa surface crust types were obtained by supervised classification of remote sensing images,and the salt dust release potential of crusts was explored by the wind tunnel experiments.The field investigation of Qehan Lake revealed that playa surface crust types had a circum-lake band distribution from the inside to the outside of this lake,which were successively vegetated areas,clay flats,salt crusts,and margins.The spatial distribution patterns of playa surface crust types were mainly controlled by the hydrodynamics of the playa,soil texture,and groundwater.There was a significant negative correlation between crust thickness and electrical conductivity.The results of the wind tunnel experiments showed that the initial threshold of friction wind velocity for the salt dust release was higher in clay flats(0.7–0.8 m/s)than in salt crusts(0.5–0.6 m/s).Moreover,the particle leap impact processes occurring under natural conditions may reduce this threshold value.Salinity was the main factor controlling the difference in the initial threshold of friction wind velocity for the salt dust release of clay flats and salt crusts.This study provides a scientific reference for understanding how salt dust is released from a lakebed,which may be used for ecological restoration of dry salt lakes. 展开更多
关键词 playa surface crust curly crusts salt crusts salt dust release wind tunnel experiments Qehan Lake
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Expert Experience and Data-Driven Based Hybrid Fault Diagnosis for High-SpeedWire Rod Finishing Mills 被引量:1
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作者 Cunsong Wang Ningze Tang +3 位作者 Quanling Zhang Lixin Gao Haichen Yin Hao Peng 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第2期1827-1847,共21页
The reliable operation of high-speed wire rod finishing mills is crucial in the steel production enterprise.As complex system-level equipment,it is difficult for high-speed wire rod finishing mills to realize fault lo... The reliable operation of high-speed wire rod finishing mills is crucial in the steel production enterprise.As complex system-level equipment,it is difficult for high-speed wire rod finishing mills to realize fault location and real-time monitoring.To solve the above problems,an expert experience and data-driven-based hybrid fault diagnosis method for high-speed wire rod finishing mills is proposed in this paper.First,based on its mechanical structure,time and frequency domain analysis are improved in fault feature extraction.The approach of combining virtual value,peak value with kurtosis value index,is adopted in time domain analysis.Speed adjustment and side frequency analysis are proposed in frequency domain analysis to obtain accurate component characteristic frequency and its corresponding sideband.Then,according to time and frequency domain characteristics,fault location based on expert experience is proposed to get an accurate fault result.Finally,the proposed method is implemented in the equipment intelligent diagnosis system.By taking an equipment fault on site,for example,the effectiveness of the proposed method is illustrated in the system. 展开更多
关键词 High-speed wire rod finishing mills expert experience DATA-DRIVEN fault diagnosis
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Process Characterization of the Transesterification of Rapeseed Oil to Biodiesel Using Design of Experiments and Infrared Spectroscopy
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作者 Tobias Drieschner Andreas Kandelbauer +1 位作者 Bernd Hitzmann Karsten Rebner 《Journal of Renewable Materials》 SCIE EI 2023年第4期1643-1660,共18页
For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the proc... For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the process and results in a mathematical description of the process behavior as a simple function based on the most important process factors can help to achieve higher production efficiency and quality.The present study aims at characterizing a well-known industrial process,the transesterification reaction of rapeseed oil with methanol to produce fatty acid methyl esters(FAME)for usage as biodiesel in a continuous micro reactor set-up.To this end,a design of experiment approach is applied,where the effects of two process factors,the molar ratio and the total flow rate of the reactants,are investigated.The optimized process target response is the FAME mass fraction in the purified nonpolar phase of the product as a measure of reaction yield.The quantification is performed using attenuated total reflection infrared spectroscopy in combination with partial least squares regression.The data retrieved during the conduction of the DoE experimental plan were used for statistical analysis.A non-linear model indicating a synergistic interaction between the studied factors describes the reactor behavior with a high coefficient of determination(R^(2))of 0.9608.Thus,we applied a PAT approach to generate further insight into this established industrial process. 展开更多
关键词 Process analytical technology TRANSESTERIFICATION design of experiment attenuated total reflection infrared spectroscopy partial least square regression
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Effects of friction stir processing and nano-hydroxyapatite on the microstructure,hardness,degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications
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作者 Bo Wu Farazila Yusof +5 位作者 Fuguo Li Huan Miao A.R.Bushroa Mohd Ridha Bin Muhamad Irfan Anjum Badruddin Mahmoud Z.Ibrahim 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第1期209-224,共16页
Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural bones.However,the rapid degradation of magnesium alloys in biological media hinders successful implantation.Refinem... Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural bones.However,the rapid degradation of magnesium alloys in biological media hinders successful implantation.Refinement of microstructure,as well as reinforcement particles can significantly improve the degradation rate.In this work,multi-pass friction stir processing(FSP)was proposed to synthesize WE43/nano-hydroxyapatite(n HA)surface composite,the microstructure,reinforced particle distribution,micro-hardness,corrosion behavior and in-vitro bioactivity were studied.The subsequent FSP passes of WE43 alloy and WE43/n HA composite refined the grain size which was reduced by 94.29%and 95.92%(2.63 and 1.88μm,respectively)compared to base metal after three passes.This resulted in increasing the microhardness by 120%(90.86 HV0.1)and 135%(105.59 HV0.1)for the WE43 and WE43-n HA,respectively.It is found that increasing FSP passes improved the uniform distribution of n HA particles within the composite matrix which led to improved corrosion resistance and less degradation rate.The corrosion rate of the FSPed WE43/n HA composite after three passes was reduced by 38.2%(4.13 mm/year)and the degradation rate was reduced by 69.7%(2.87 mm/y).This is attributed to secondary phase(Mg24Y5and Mg41Nd5)particle fragmentation and redistribution,as well as a homogeneous distribution of n HA.Additionally,the growing Ca-P and Mg(OH)2layer formed on the surface represented a protective layer that reduced the degradation rate.The wettability test revealed a relatively hydrophilic surface with water contact angle of 49.1±2.2°compared to 71.2±2.1°for base metal.Also,biomineralization test showed that apatite layer grew after immersion 7d in simulated body fluid with atomic ratio of Ca/P 1.60 approaching the stoichiometric ratio(1.67)indicating superior bioactivity of FSPed WE43/n HA composite after three passes.These results raise that the grain refinement by FSP and introduction of n HA particles significantly improved the degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications. 展开更多
关键词 Friction stir processing Magnesium-based composite NANO-HYDROXYAPATITE Corrosion behavior in-vitro bioactivity
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Finding biomarkers of experience in animals
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作者 Sarah Babington Alan J.Tilbrook +9 位作者 Shane K.Maloney Jill N.Fernandes Tamsyn M.Crowley Luoyang Ding Archa H.Fox Song Zhang Elise A.Kho Daniel Cozzolino Timothy J.Mahony Dominique Blache 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第3期925-944,共20页
At a time when there is a growing public interest in animal welfare,it is critical to have objective means to assess the way that an animal experiences a situation.Objectivity is critical to ensure appropriate animal ... At a time when there is a growing public interest in animal welfare,it is critical to have objective means to assess the way that an animal experiences a situation.Objectivity is critical to ensure appropriate animal welfare outcomes.Existing behavioural,physiological,and neurobiological indicators that are used to assess animal welfare can verify the absence of extremely negative outcomes.But welfare is more than an absence of negative outcomes and an appropriate indicator should reflect the full spectrum of experience of an animal,from negative to positive.In this review,we draw from the knowledge of human biomedical science to propose a list of candidate biological markers(biomarkers)that should reflect the experiential state of non-human animals.The proposed biomarkers can be classified on their main function as endocrine,oxidative stress,non-coding molecular,and thermobiological markers.We also discuss practical challenges that must be addressed before any of these biomarkers can become useful to assess the experience of an animal in real-life. 展开更多
关键词 Animal experience Animal welfare BIOMARKER STRESS Welfare assessment
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Experimental Investigation on Vertical Hydraulic Transport of Ores in Deepsea Mining
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作者 LIU Lei LIU Jian-cheng +2 位作者 LI Xin XU Li-xin ZHANG Xiu-zhan 《China Ocean Engineering》 SCIE EI CSCD 2024年第1期42-53,共12页
Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for... Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial applications.In the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle velocity.The hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow velocities.During transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture velocity.The qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were investigated.The local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic gradient.The effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport. 展开更多
关键词 deepsea mining vertical hydraulic transport experiment flow characteristics
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From the perspective of experimental practice: High-throughput computational screening in photocatalysis
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作者 Yunxuan Zhao Junyu Gao +2 位作者 Xuanang Bian Han Tang Tierui Zhang 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第1期1-6,共6页
Photocatalysis,a critical strategy for harvesting sunlight to address energy demand and environmental concerns,is underpinned by the discovery of high-performance photocatalysts,thereby how to design photocatalysts is... Photocatalysis,a critical strategy for harvesting sunlight to address energy demand and environmental concerns,is underpinned by the discovery of high-performance photocatalysts,thereby how to design photocatalysts is now generating widespread interest in boosting the conversion effi-ciency of solar energy.In the past decade,computational technologies and theoretical simulations have led to a major leap in the development of high-throughput computational screening strategies for novel high-efficiency photocatalysts.In this viewpoint,we started with introducing the challenges of photocatalysis from the view of experimental practice,especially the inefficiency of the traditional“trial and error”method.Sub-sequently,a cross-sectional comparison between experimental and high-throughput computational screening for photocatalysis is presented and discussed in detail.On the basis of the current experimental progress in photocatalysis,we also exemplified the various challenges associated with high-throughput computational screening strategies.Finally,we offered a preferred high-throughput computational screening procedure for pho-tocatalysts from an experimental practice perspective(model construction and screening,standardized experiments,assessment and revision),with the aim of a better correlation of high-throughput simulations and experimental practices,motivating to search for better descriptors. 展开更多
关键词 PHOTOCATALYSIS High-throughput computational screening PHOTOCATALYST Theoretical simulations experiments
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Acceptance and Experience of HIV-Infected Adolescents in Two Hospitals in Yaoundé
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作者 Isabelle Mekone Nkwele Nelly Kamgaing +7 位作者 Pierrette Amanda Emah Manga Jeannette Épée Ngoué Hélène Kamo Sélangai Claude Audrey Meguieze Nsoh Ndeh-Fofang Serge Tchoukoua Jean-Baptiste Fotso Djemo Paul Koki Ndombo 《Open Journal of Pediatrics》 2024年第2期435-443,共9页
Introduction: Access to antiretroviral drugs has improved the survival of children infected with the Human Immunodeficiency Virus (HIV). As they reach adolescence, they are confronted with various constraints related ... Introduction: Access to antiretroviral drugs has improved the survival of children infected with the Human Immunodeficiency Virus (HIV). As they reach adolescence, they are confronted with various constraints related to the infection and its treatment, in addition to those of the growth period they are going through. The main aim of the study was to assess the acceptance and describe the experience of HIV infection by infected adolescents but also to investigate the factors associated with good acceptance and a positive experience. Methodology: The cross-sectional analytic study concerned HIV-infected adolescents aged 15 to 19 followed up at the Chantal Biya Foundation-Mother and Child Centre (CME-FCB) and the Yaoundé University Hospital Centre (CHUY) between February 2020 and June 2020. The study saw participants complete a questionnaire containing socio-demographic data and assessing acceptance and experience with the infection. Data analysis was accomplished using Epi info software version 7.2.2.6. Results: One hundred and thirteen HIV-infected adolescents were included in the study. The sex ratio was 0.68 and the mean age was 17 years. More than half of the adolescents had a good acceptance and positive experience with the infection. Related factors were the adolescent’s perception of good health and participation in an association with other infected adolescents. Conclusion: Emphasizing the psychological and educational follow-up of infected adolescents and encouraging their participation in associations for adolescents living with HIV could reduce the consequences of poor acceptance and ensure a better transition to adulthood. . 展开更多
关键词 HIV ADOLESCENT ACCEPTANCE experiENCE
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Multi-environment BSA-seq using large F3 populations is able to achieve reliable QTL mapping with high power and resolution: An experimental demonstration in rice
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作者 Yan Zheng Ei Ei Khine +9 位作者 Khin Mar Thi Ei Ei Nyein Likun Huang Lihui Lin Xiaofang Xie Min Htay Wai Lin Khin Than Oo Myat Myat Moe San San Aye Weiren Wu 《The Crop Journal》 SCIE CSCD 2024年第2期549-557,共9页
Bulked-segregant analysis by deep sequencing(BSA-seq) is a widely used method for mapping QTL(quantitative trait loci) due to its simplicity, speed, cost-effectiveness, and efficiency. However, the ability of BSA-seq ... Bulked-segregant analysis by deep sequencing(BSA-seq) is a widely used method for mapping QTL(quantitative trait loci) due to its simplicity, speed, cost-effectiveness, and efficiency. However, the ability of BSA-seq to detect QTL is often limited by inappropriate experimental designs, as evidenced by numerous practical studies. Most BSA-seq studies have utilized small to medium-sized populations, with F2populations being the most common choice. Nevertheless, theoretical studies have shown that using a large population with an appropriate pool size can significantly enhance the power and resolution of QTL detection in BSA-seq, with F_(3)populations offering notable advantages over F2populations. To provide an experimental demonstration, we tested the power of BSA-seq to identify QTL controlling days from sowing to heading(DTH) in a 7200-plant rice F_(3)population in two environments, with a pool size of approximately 500. Each experiment identified 34 QTL, an order of magnitude greater than reported in most BSA-seq experiments, of which 23 were detected in both experiments, with 17 of these located near41 previously reported QTL and eight cloned genes known to control DTH in rice. These results indicate that QTL mapping by BSA-seq in large F_(3)populations and multi-environment experiments can achieve high power, resolution, and reliability. 展开更多
关键词 BSA-seq QTL mapping Large F3 population Multi-environment experiment Cross-validation
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Analysis and experimental study on resistance-increasing behavior of composite high efficiency autonomous inflow control device
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作者 Liang-Liang Dong Yu-Lin Zhang 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1290-1304,共15页
Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks th... Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore. Autonomous inflow control device(AICD) is an important instrument maintain normal production after bottom water coning, however, the resistance increasing ability of the swirl type AICD is insufficient at present, which seriously affects the water control effect. Aiming this problem, this paper designs a multi-stage resistance-increasing and composite type AICD. The separation mechanism of oil-water two phases in this structure, the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed. Establishing the dual-phase multi-stage separation and resistance-increasing model, and verified by measuring the throttling pressure drop and oil-water volume fraction of the AICD, it is found that the composite type AICD has the effect of ICD and AICD at the same time, which can balance the production rate of each well section at the initial stage of production, delay the occurrence of bottom water coning. In the middle and later stages of production, water-blocking can be effectively increased to achieve water control and stable production.After structural sensitivity analysis, the influence law of various structural parameters on the water control performance of composite AICD was obtained. The simulation calculation results show that,compared with the existing swirl type AICD, composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average. The composite AICD is suitable for the entire stage of horizontal well production. 展开更多
关键词 Water control Flow separation Flow resistance-increasing AICD device Simulation and experiment
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Unexpected Diversity in Ecosystem Nutrient Responses to Experimental Drought in Temperate Grasslands
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作者 Biying Qiu Niwu Te +8 位作者 Lin Song Yuan Shi Chuan Qiu Xiaoan Zuo Qiang Yu Jianqiang Qian Zhengwen Wang Honghui Wu Wentao Luo 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第4期831-841,共11页
The responses of ecosystem nitrogen (N) and phosphorus (P) to drought are an important component of globalchange studies. However, previous studies were more often based on site-specific experiments, introducing a sig... The responses of ecosystem nitrogen (N) and phosphorus (P) to drought are an important component of globalchange studies. However, previous studies were more often based on site-specific experiments, introducing a significantuncertainty to synthesis and site comparisons. We investigated the responses of vegetation and soil nutrientsto drought using a network experiment of temperate grasslands in Northern China. Drought treatment (66%reduction in growing season precipitation) was imposed by erecting rainout shelters, respectively, at the driest,intermediate, and wettest sites. We found that vegetation nutrient concentrations increased but soil nutrient concentrationsdecreased along the aridity gradient. Differential responses were observed under experimentaldrought among the three grassland sites. Specifically, the experimental drought did not change vegetation andsoil nutrient status at the driest site, while strongly reduced vegetation but increased soil nutrient concentrationsat the site with intermediate precipitation. On the contrary, experimental drought increased vegetation N concentrationsbut did not change vegetation P and soil nutrient concentrations at the wettest site. In general, the differentialeffects of drought on ecosystem nutrients were observed between manipulative and observationalexperiments as well as between sites. Our research findings suggest that conducting large-scale, consistent, andcontrolled network experiments is essential to accurately evaluate the effects of global climate change on terrestrialecosystem bio-geochemistry. 展开更多
关键词 Climate change drought experiment PRECIPITATION nutrient cycles
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Analysis of the Erosion-Corrosion Mechanism of the Air Cooler in a Hydrocracking Unit:A Numerical and Experimental Study
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作者 Su Guoqing Li Yan +1 位作者 Guo Hongli Zhang Jianwen 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2024年第1期126-138,共13页
Corrosion leakages often occur in the air cooler of a hydrocracking unit,with the failure sites mainly located in the entrance area of the tubes.An analysis of the macroscopic morphology and corrosion products confirm... Corrosion leakages often occur in the air cooler of a hydrocracking unit,with the failure sites mainly located in the entrance area of the tubes.An analysis of the macroscopic morphology and corrosion products confirmed that the damage was caused by erosion-corrosion(E-C).Numerical and experimental methods were applied to investigate the E-C mechanism in the air cooler.Computational fluid dynamics(CFD)was used to calculate the hydrodynamic parameters of the air cooler.The results showed that there was a biased flow in the air cooler,which led to a significant increase in velocity,turbulent kinetic energy and wall shear within 0.2 m of the tube entrance.A visualization experiment was then performed to determine the principles of migration and transformation of multiphase flow in the air cooler tubes.Various flow patterns(pure droplet flow,mist flow,and annular flow)and their evolutionary processes were clearly depicted experimentally.The initiation mechanism and processes leading to the development of E-C in the air cooler were also determined.This study provided a comprehensive explanation for the E-C failures that occur in air coolers during operation. 展开更多
关键词 air cooler hydrocracking unit EROSION-CORROSION SIMULATION visualization experiment multiphase flow
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Visualization and characterization of experimental hydraulic fractures interacting with karst fracture-cavity distributions
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作者 Hanzhi Yang Xin Chang +4 位作者 Chunhe Yang Wuhao Guo Lei Wang Guokai Zhao Yintong Guo 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1667-1683,共17页
Karst fracture-cavity carbonate reservoirs,in which natural cavities are connected by natural fractures to form cavity clusters in many circumstances,have become significant fields of oil and gas exploration and explo... Karst fracture-cavity carbonate reservoirs,in which natural cavities are connected by natural fractures to form cavity clusters in many circumstances,have become significant fields of oil and gas exploration and exploitation.Proppant fracturing is considered as the best method for exploiting carbonate reservoirs;however,previous studies primarily focused on the effects of individual types of geological formations,such as natural fractures or cavities,on fracture propagation.In this study,true-triaxial physical simulation experiments were systematically performed under four types of stress difference conditions after the accurate prefabrication of four types of different fracture-cavity distributions in artificial samples.Subsequently,the interaction mechanism between the hydraulic fractures and fracture-cavity structures was systematically analyzed in combination with the stress distribution,cross-sectional morphology of the main propagation path,and three-dimensional visualization of the overall fracture network.It was found that the propagation of hydraulic fractures near the cavity was inhibited by the stress concentration surrounding the cavity.In contrast,a natural fracture with a smaller approach angle(0°and 30°)around the cavity can alleviate the stress concentration and significantly facilitate the connection with the cavity.In addition,the hydraulic fracture crossed the natural fracture at the 45°approach angle and bypassed the cavity under higher stress difference conditions.A new stimulation effectiveness evaluation index was established based on the stimulated reservoir area(SRA),tortuosity of the hydraulic fractures(T),and connectivity index(CI)of the cavities.These findings provide new insights into the fracturing design of carbonate reservoirs. 展开更多
关键词 Karst fracture-cavity reservoir Fracturing experiment Fracture propagation Cross-sectional morphology Stimulation effectiveness
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Experiences of Mothers on the Utilization of Elimination of Mother to Child Transmission of HIV Services at Mtendere Clinic, Lusaka
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作者 Ireen Kasongo Silavwe Patricia Katowa Mukwato +2 位作者 Sebean Mayimbo Febiano Phiri Laura Lubinda 《Journal of Biosciences and Medicines》 2024年第4期298-318,共21页
Introduction: Acquired immunodeficiency syndrome is one of the leading causes of mortality among women of reproductive age and Mother to Child Transmission of Human immunodeficiency virus is still a challenge affectin... Introduction: Acquired immunodeficiency syndrome is one of the leading causes of mortality among women of reproductive age and Mother to Child Transmission of Human immunodeficiency virus is still a challenge affecting many countries. Globally, an estimation of 180,000 children under 15 years acquire the Human immunodeficiency virus every day, and more than 90% of those infections are due to Mother to Child Transmission. The study sought to explore the experiences of mothers on the Elimination of Mother to Child Transmission-HIV services at Mtendere Clinic, Lusaka. Materials and Methods: Qualitative interpretive phenomenology study design was employed using in-depth interviews to collect data from a sample that was selected using purposive sampling technique. Thirteen participants were recruited, and these were HIV-positive mothers at least between the ages of 15 and 49 years and enrolled in the Elimination of Mother To Child Transmission-HIV program. The in-depth interviews were audiotape recorded and transcribed verbatim. Data was analyzed using thematic method. Findings: Three main themes that emerged are;living with HIV, support system and barriers to utilization of Elimination of Mother To Child Transmission-HIV services. Most of the participants expressed having acquired knowledge from the program, and received counselling and support from spouses, family as well as health personnel at Mtendere health facility which culminated into a positive experience and enhanced their uptake of the Elimination of Mother to Child Transmission-HIV services. However, barriers to service utilization were identified and these included fear of stigma, negative attitudes from health workers, long waiting times, lack of support and lack of transport to the health facility. Conclusion: Interventions such as community awareness campaigns on Elimination of Mother To Child Transmission-HIV, male involvement and implementing mother-to-mother peer support strategies in Elimination of Mother To Child Transmission-HIV service utilization should be prioritized so as to alleviate stigma and enhancing a positive experience for these mothers thus reducing on the Mother to Child HIV Transmission burden and mortality rates. 展开更多
关键词 Elimination of Mother-to-Child Transmission experiences Barriers UTILIZATION HIV/AIDS
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Community Caregivers’ Experiences and Programmatic Strategies to Improve Active Case Finding in Community Tuberculosis Care in Botswana 2016-2021
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作者 Unami Modongo-Mathebula Mary Moleki Tefera Agizew 《Journal of Tuberculosis Research》 2024年第2期105-118,共14页
Background: The community tuberculosis care program was started to reduce the impact of TB and increase successful treatment outcomes, thus contributing to meeting WHO targets on TB. According to the Botswana Ministry... Background: The community tuberculosis care program was started to reduce the impact of TB and increase successful treatment outcomes, thus contributing to meeting WHO targets on TB. According to the Botswana Ministry of Health, community tuberculosis care was introduced with the main goal of reducing tuberculosis-related morbidity and mortality among communities through the expansion of direct observed therapy and community involvement to community settings. The community caregivers were to support tuberculosis patients throughout their treatment period until they were cured or had completed their treatment. Settings: Two major cities of Botswana, Francistown and Gaborone, with more than twenty-two health clinics offering tuberculosis care. Objective: To investigate community caregivers’ experiences and identify programmatic strategies to improve active TB case findings under the community TB care (CTBC) program in Botswana during 2016-2021. Methods: We adopted a descriptive qualitative research design, followed by convenience purposive sampling. We obtained consent and interviewed 40 participants who met the inclusion criteria, 16 out of 73 in Gaborone and 24 out of 38 from Francistown. Results: We interviewed 40 caregivers with a mean age of 43.4 years. Accepting the caregiving role was identified as the main experience by more than two thirds of the caregivers. While at least more than two-fifth felt obligated to care for the patient at home due to personal relations. More than half of the respondents found caregiving difficult or frustrating due to some challenges encountered during the caregiving role. Behavioral modifications were suggested under different subthemes as strategies to improve active case finding. [-rId13-]Conclusion: Acceptance was the major experience in CTBC. Intensification of known programmatic strategies was suggested by caregivers to improve tuberculosis active case finding in CTBC. 展开更多
关键词 Community experiences CAREGIVERS Active Case Finding TUBERCULOSIS Community Tuberculosis Care
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Theoretical and experimental investigation of the resonance responses and chaotic dynamics of a bistable laminated composite shell in the dynamic snap-through mode
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作者 Meiqi WU Pengyu LV +3 位作者 Hongyuan LI Jiale YAN Huiling DUAN Wei ZHANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第4期581-602,共22页
The dynamic model of a bistable laminated composite shell simply supported by four corners is further developed to investigate the resonance responses and chaotic behaviors.The existence of the 1:1 resonance relations... The dynamic model of a bistable laminated composite shell simply supported by four corners is further developed to investigate the resonance responses and chaotic behaviors.The existence of the 1:1 resonance relationship between two order vibration modes of the system is verified.The resonance response of this class of bistable structures in the dynamic snap-through mode is investigated,and the four-dimensional(4D)nonlinear modulation equations are derived based on the 1:1 internal resonance relationship by means of the multiple scales method.The Hopf bifurcation and instability interval of the amplitude frequency and force amplitude curves are analyzed.The discussion focuses on investigating the effects of key parameters,e.g.,excitation amplitude,damping coefficient,and detuning parameters,on the resonance responses.The numerical simulations show that the foundation excitation and the degree of coupling between the vibration modes exert a substantial effect on the chaotic dynamics of the system.Furthermore,the significant motions under particular excitation conditions are visualized by bifurcation diagrams,time histories,phase portraits,three-dimensional(3D)phase portraits,and Poincare maps.Finally,the vibration experiment is carried out to study the amplitude frequency responses and bifurcation characteristics for the bistable laminated composite shell,yielding results that are qualitatively consistent with the theoretical results. 展开更多
关键词 bistable laminated composite shell dynamic snap-through mode Hopf bifurcation chaotic dynamics vibration experiment
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