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Enhancing the stability of influenza a reporter viruses by recoding the gfp gene 认领 引用
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作者 Jing Hu Jianchao Li +3 位作者 Qifeng Li Shengqiang Jiang Ziqian Cao Hongying Chen 《Virologica Sinica》 SCIE CAS CSCD 2026年第1期119-131,共13页
Influenza A virus(IAV)is one of the most important zoonotic pathogens and can cause global influenza pandemics and seasonal influenza outbreaks.Generation of recombinant IAV expressing a fluorescent protein will allow... Influenza A virus(IAV)is one of the most important zoonotic pathogens and can cause global influenza pandemics and seasonal influenza outbreaks.Generation of recombinant IAV expressing a fluorescent protein will allow the infection to be easily monitored.In this study,we initially constructed a replication-defective H1N1/ΔPB2-GFP and a replication-competent H1N1/NS-GFP.However,these two reporter IAVs exhibited genetic instability.To stabilize the recombinant viral genome,we recoded the gfp sequence(rGFP)using synonymous codons to mimic the high-NP-binding regions involved in NP-vRNA interaction.This approach resulted in the development of replication-defective H1N1/ΔPB2(300)-rGFP and replication-competent H1N1/NS-rGFP,both of which exhibited enhanced stability in GFP expression.By replacing the HA segment from strain A/mink/China/CY 2017(H5N1),we also generated a replication-defective H5N1/ΔPB2(300)-rGFP,which showed excellent genetic stability.Using these reporter IAVs,the blocking of virus infection by neutralizing antibodies and antivirals can be rapidly detected by the loss of fluorescent reporter expression.Replication-defective reporter IAVs constructed in this study can only infect and replicate in cells expressing PB2,allowing the possibility of manipulation of highly pathogenic IAV and their related reassortant strains in biosafety level-2 laboratories.Our data highlight the importance of NP-vRNA interaction for the stability of IAV genome,and the reporter IAVs generated using this strategy could be powerful tools for both basic and applied influenza virus research. 展开更多
关键词 Influenza virus GFP Recoding GFP Replication-defective virus Replication-competent virus Synonymous mutation
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Scattering Center Modeling Using Adaptive Segmental Compressive Sampling 认领 引用 被引量：1
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作者 Qifeng Li Kunyi Guo +2 位作者 Jiaxin Wang Xinqing Sheng Tianshu Liu 《Journal of Beijing Institute of Technology》 EI CAS 2017年第4期484-493,共10页
In order to deal with aliasing distortions of Doppler frequencies shown in time-frequency representation（ TFR） with aspect undersampling,an approach using adaptive segmental compressive sampling according to the asp... In order to deal with aliasing distortions of Doppler frequencies shown in time-frequency representation（ TFR） with aspect undersampling,an approach using adaptive segmental compressive sampling according to the aspect dependencies of the scattering centers is proposed. The random noise problem induced by compressive sampling is solved by employing a series of signal processing techniques of filtering,image transformation and Hough Transform. Three examples are presented to verify the effectiveness of this approach. The comparisons between the built models and the precise scattered fields computed by a well-validated full-wave numerical method are investigated,and the results showgood agreements between each other. 展开更多
关键词 scattering center undersampling compressive sensing time-frequency representation parameter estimation
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Mg-Zn-Mn alloys degradation in pancreatic fluid:Trypsin disrupts passivation for stent design 认领 引用 被引量：1
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作者 Qifeng Li Senwei Wang +3 位作者 Jia She Xianhua Chen Lu Chen Shixiang Guo 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2025年第10期4862-4876,共15页
Biodegradable magnesium alloys show promising potential for pancreatic duct stents,yet their degradation varies significantly across physiological environments.This study compared the corrosion rates of extruded Mg-2Z... Biodegradable magnesium alloys show promising potential for pancreatic duct stents,yet their degradation varies significantly across physiological environments.This study compared the corrosion rates of extruded Mg-2Zn-xMn(x=0,0.5,1.0,1.5 wt.%)alloys in human pancreatic fluid.The results revealed that the alloys undergo different corrosion mechanisms in human pancreatic fluid,emphasizing the necessity of conducting evaluations under physiologically relevant conditions.Further investigations into the degradation mechanism in pancreatic fluid indicated that the alkaline PH(8.3–8.7),high bicarbonate concentration,and enzymatic activity significantly influence the corrosion process.Electrochemical and immersion tests showed rapid initial corrosion due to Cl−attack,followed by the formation of a protective Mg(OH)2,MgCO3,and Ca3(PO4)2layer that slowed degradation.However,digestive enzymes,particularly trypsin,disrupt passivation by interacting with organic components,leading to pitting and filiform corrosion.Among the investigated alloys,Mg-2Zn-1.0Mn exhibited the most favorable combination of corrosion resistance,mechanical performance,and cytocompatibility.This study highlights the critical impact of pancreatic fluid on magnesium alloy degradation and stresses the need for physiologically accurate evaluations. 展开更多
关键词 Magnesium alloy Biodegradable stent Pancreatic fluid Corrosion mechanism Mn addition
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Mild hypothermia combined with neural stem cell transplantation for hypoxic-ischemic encephalopathy: neuroprotective effects of combined therapy 认领 引用 被引量：12
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作者 Lin Wang Feng Jiang +2 位作者 Qifeng Li Xiaoguang He Jie Ma 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第19期1745-1752,共8页
Neural stem cell transplantation is a useful treatment for ischemic stroke, but apoptosis often occurs in the hypoxic-ischemic environment of the brain after cell transplantation. In this study, we determined if mild ... Neural stem cell transplantation is a useful treatment for ischemic stroke, but apoptosis often occurs in the hypoxic-ischemic environment of the brain after cell transplantation. In this study, we determined if mild hypothermia （27-28~C） can increase the survival rate of neural stem cells （1.0 x 105/~tL） transplanted into neonatal mice with hypoxic-ischemic encephalopathy. Long-term effects on neurological functioning of the mice were also examined. After mild hy- pothermia combined with neural stem cell transplantation, we observed decreased expression levels of inflammatory factor nuclear factor-kappa B and apoptotic factor caspase-3, reduced cerebral infarct volumes, increased survival rate of transplanted cells, and marked improvements in neurological function. Thus, the neuroprotective effects of mild hypothermia combined with neural stem cell transplantation are superior to those of monotherapy. Moreover, our findings suggest that the neuroprotective effects of mild hypothermia combined with neural stem cell transplantation on hypoxic-ischemic encephalopathy are achieved by anti-inflammatory and an- ti-apoptotic mechanisms. 展开更多
关键词 nerve regeneration brain injury hypoxic-ischemic encephalopathy neural precursorcells hypothermia neural stem cells cell transplantation hippocampus neuron cell apoptosis astrocytes oligodendrotytes neuroprotection NSFC grants neural regeneration
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Prevalent fecal contamination in drinking water resources and potential health risks in Swat, Pakistan 认领 引用 被引量：2
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作者 Kifayatullah Khan Yonglong Lu +13 位作者 Mian Abdal Saeed Hazrat Bilal Hassan Sher Hizbullah Khan Jafar Ali Pei Wang Herman Uwizeyimana Yvette Baninla Qifeng Li Zhaoyang Liu Javed Nawab Yunqiao Zhou Chao Su Ruoyu Liang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第10期1-12,共12页
Fecal bacteria contaminate water resources and result in associated waterborne diseases.This study assessed drinking water quality and evaluated their potential health risks in Swat, Pakistan. Ground and surface drink... Fecal bacteria contaminate water resources and result in associated waterborne diseases.This study assessed drinking water quality and evaluated their potential health risks in Swat, Pakistan. Ground and surface drinking water were randomly collected from upstream to downstream in the River Swat watershed and analyzed for fecal contamination using fecal indicator bacteria（Escherichia coli） and physiochemical parameters（potential of hydrogen, turbidity, temperature, electrical conductivity, total dissolved solid, color, odor and taste）. The physiochemical parameters were within their safe limits except in a few locations, whereas, the fecal contaminations in drinking water resources exceeded the drinking water quality standards of Pakistan Environmental Protection Agency（Pak-EPA）,2008 and World Health Organization（WHO）, 2011. Multivariate and univariate analyses revealed that downstream urbanization trend, minimum distance between water sources and pit latrines/sewerage systems, raw sewage deep well injection and amplified urban,pastures and agricultural runoffs having human and animal excreta were the possible sources of contamination. The questionnaire survey revealed that majority of the local people using 10–20 years old drinking water supply schemes at the rate of 73% well supply,13% hand pump supply, 11% spring supply and 3% river/streams supply, which spreads high prevalence of water borne diseases including hepatitis, intestinal infections and diarrhea, dysentery, cholera, typhoid fever, jaundice and skin diseases in children followed by older and younger adults. 展开更多
关键词 Drinking water Fecal contamination Health risks Pakistan
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Medical ozone alleviates acute lung injury by enhancing phagocytosis targeting NETs via AMPK/SR-A1 axis 认领 引用 被引量：6
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作者 Chenxiao Yan Yong Zhang +10 位作者 Lai Jin Xiaojie Liu Xuexian Zhu Qifeng Li Yu Wang Liang Hu Xueming He Hongguang Bao Xia Zhu Qian Wang Wen-Tao Liu 《Journal of Biomedical Research》 CAS CSCD 2024年第6期569-584,共16页
Acute lung injury(ALI)linked to sepsis has a high mortality rate,with limited treatment options available.In recent studies,medical ozone has shown the potential to alleviate inflammation and infection.Here,we aimed t... Acute lung injury(ALI)linked to sepsis has a high mortality rate,with limited treatment options available.In recent studies,medical ozone has shown the potential to alleviate inflammation and infection.Here,we aimed to evaluate therapeutic potential of medical ozone in a mouse model of the sepsis-induced ALI by measuring behavioral assessments,lung function,and blood flow.Protein levels were quantified by Western blotting.In vitro,we performed experiments on bone marrow-derived macrophages(BMDMs)to investigate the effect of adenosine monophosphate(AMP)-activated protein kinase(AMPK)inhibitors and agonists on their phagocytic activity.The results showed that medical ozone significantly improved the survival rate,ameliorated lung injury,and enhanced lung function and limb microcirculation in mice with ALI.Notably,medical ozone inhibited the formation of neutrophil extracellular traps(NETs),a crucial factor in the ALI development.Additionally,medical ozone counteracted the elevated levels of tissue factor,matrix metalloproteinase-9,and interleukin-1β.In the ALI mice,the effects of ozone were abolished,and BMDMs showed an impaired capacity to engulf NETs following the Sr-a1 knockout.Under normal physiological conditions,the administration of an AMPK antagonist showed similar effects on the Sr-a1 knockout,significantly inhibiting the phagocytosis of NETs by BMDMs.In contrast,AMPK agonists enhanced this phagocytic process.In conclusion,medical ozone may alleviate the sepsis-induced lung injury through the AMPK/SR-A1 pathway,thereby enhancing the phagocytosis of NETs by macrophages. 展开更多
关键词 SR-A1 NETs ALI phagocytosis ozone therapy
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Tolerance of neurite outgrowth to Rho kinase inhibitors decreased by cyclooxygenase-2 inhibitor 认领 引用 被引量：1
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作者 Weigang Duan Ling Que +3 位作者 Xiaoman Lv Qifeng Li Hua Yin Luyong Zhang 《Neural Regeneration Research》 SCIE CAS CSCD 2012年第34期2705-2712,共8页
In this study, PC12 Adh cells and Neuro-2a cells were treated with Rho-associated kinase inhibitors （Y27632 and Fasudil）, a cyclooxygenase-1 selective inhibitor （SC560）, and a cyclooxygenase-2 inhibitor （NS398）.... In this study, PC12 Adh cells and Neuro-2a cells were treated with Rho-associated kinase inhibitors （Y27632 and Fasudil）, a cyclooxygenase-1 selective inhibitor （SC560）, and a cyclooxygenase-2 inhibitor （NS398）. We found that these cells became tolerant to Rho-associated kinase inhibitors, as neurite outgrowth induced by these inhibitors diminished following more than 3 days of exposure in either cell line. The proteins cyclooxygenase-2 and cytosolic prostaglandin E synthetase were upregulated at day 3. NS398 decreased the tolerance to neurite outgrowth induction in both cell lines, whereas SC560 had almost no effect. These findings indicate that cells become tolerant to neurite outgrowth induced by Rho-associated kinase inhibitors, this is at least partly associated with upregulation of proteins involved in the cyclooxygenase-2 pathway, and cyclooxygenases-2 inhibition prevents this tolerance. 展开更多
关键词 Rho-associated kinase inhibitors Y27632 fasudil neurite cyclooxygenase 2 inhibitors drugtolerance
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Preventive-corrective Control for Static Voltage Stability Under Multiple N-1 Contingencies Considering Wind Power Uncertainty 认领 引用
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作者 Yuerong Yang Shunjiang Lin +2 位作者 Qiong Wang Mingbo Liu Qifeng Li 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2025年第4期1466-1480,共15页
An optimal preventive-corrective control model for static voltage stability under multiple N-1 contingencies considering the wind power uncertainty is established in this paper.The objective is to minimize the control... An optimal preventive-corrective control model for static voltage stability under multiple N-1 contingencies considering the wind power uncertainty is established in this paper.The objective is to minimize the control variable adjustment cost including the load shedding cost of each contingency.The chance constraints of the static voltage stability margins(SvSMs)in the normal operation state and after each N-1 contingency are included.The approximate functions between the probability density functions(PDFs)of SVSMs and load shedding quantity with respect to preventive control variables are obtained to transform the expectation of load shedding quantity and the SvSM chance constraints into deterministic expressions.An approximate sequential convex quadratically constrained quadratic programming iteration method is proposed to solve the optimal control model.In each iteration,the approximate expressions and range are determined by the generated data samples.Moreover,a fast approximation calculation method of second-order matrices is proposed.By the naive Bayes classifier,the most severe N-1 contingencies are selected to replace all the contingencies to be added to the optimization model to improve the computational efficiency.Case studies on the IEEE-39 bus system and an actual provincial power grid demonstrate the effectiveness and efficiency of the proposed method. 展开更多
关键词 Multiple N-1 contingencies preventivecorrective control probabilistic distribution control sequential convex quadratically constrained quadratic programming static voltage stability margin wind power uncertainty
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Chirality-induced spin selectivity of graphene chiral superstructures and their true/false chirality of electron motion 认领 引用
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作者 Xueying Qin Yi Sun +6 位作者 Yamei Guo Xiaopeng Li Ji Liu Zhuwei Zhang Xiangyun Ma Qifeng Li Yongtao Shen 《Nano Research》 SCIE EI CSCD 2025年第10期5-9,共5页
“Chiral-induced spin selectivity(CISS)”and its device applications are predominantly at the experimental stage,with mechanisms not fully understood.There is a need for new chiral materials with simple structures and... “Chiral-induced spin selectivity(CISS)”and its device applications are predominantly at the experimental stage,with mechanisms not fully understood.There is a need for new chiral materials with simple structures and high room-temperature electron spin polarization rates,crucial for theoretical studies and low-power spin optoelectronic devices.This study examines the CISS effect in carbon nanotubes,graphene chiral rolls,and graphene chiral stacks.While all three exhibit chirality,only the one-side follow curved surface of the graphene rolls demonstrates the CISS effect.Using true and false chirality analysis from Professor Barron,we found that only the charge motion(current)on the chiral surface is true chiral,leading to spin polarization.Thus,the CISS phenomenon occurs when charge motion on the chiral surface is chiral.Both chiral surface structures and chiral charge motion are necessary for electron spin polarization.Further theoretical validation of these conditions will enhance CISS theory. 展开更多
关键词 graphene chiral superstructure chiral-induced spin selectivity ture/false chirality
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基于多源数据的华北平原夏玉米种植区划研究 认领 引用 被引量：1
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作者 刁兴良 杨再洁 +3 位作者 李奇峰 于景鑫 郑文刚 史磊刚 《智慧农业》 2019年第2期73-84,共12页
精准识别农业生产环境信息和农业生产特征,对气象、土壤和作物等多源数据进行综合分类,是提高农业资源利用效率和优化农业种植结构的基础。本研究基于近20年(1998年~2017年)气象数据和华北五省的玉米单产统计数据,首先构建了华北平原气... 精准识别农业生产环境信息和农业生产特征,对气象、土壤和作物等多源数据进行综合分类,是提高农业资源利用效率和优化农业种植结构的基础。本研究基于近20年(1998年~2017年)气象数据和华北五省的玉米单产统计数据,首先构建了华北平原气候资源和玉米生产时空分布特征数据库,研究区降雨量、活动积温、日照时数、太阳辐射和玉米单产均存在显著的时空变化;利用作物精细种植区划方法,将华北平原夏玉米种植区分为极不适应区、不适宜区、较适宜区、适宜区、极适宜区五大类,各类面积分别占总体的比例约为10%、11%、25%、30%、24%;进一步通过环境类别归属度分析方法,将每一大类分为5小类,概率大于75%的相对稳定区域约占总面积的63%,小于75%的波动区域约占37%;极不适宜区、不适宜区和较适宜区,三类时空分布比较稳定,隶属度为100%分别占各类面积的87.67%、70.41%和84.28%,波动区主要发生在极适宜区和适宜区,以及适宜区和较适宜区之间。本研究构建的华北平原夏玉米精细区划结果,对提高研究区资源利用效率和优化玉米产业布局具有重要的指导意义。 展开更多
关键词 夏玉米 多源数据 时空分布 精细区划
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A method for weighing broiler chickens using improved amplitude-limiting filtering algorithm and BP neural networks 认领 引用 被引量：11
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作者 Weihong Ma Qifeng Li +2 位作者 Jiawei Li Luyu Ding Qinyang Yu 《Information Processing in Agriculture》 EI CSCD 2021年第2期299-309,共11页
Broiler chickens are traditionally weighed by steelyard or platform scale,which is timeconsuming and labor-intensive.Broiler chickens usually exhibit stress-related behavior during weighing.The 3D camera-based weighin... Broiler chickens are traditionally weighed by steelyard or platform scale,which is timeconsuming and labor-intensive.Broiler chickens usually exhibit stress-related behavior during weighing.The 3D camera-based weighing system for broiler chickens can only weigh the broiler chicken in the monitoring area.Usually,it makes poor weight prediction due to poor segmentation especially when the broiler chicken is flapping its wings.To solve these issues,we developed one simple and low-cost weighing system with high stability and accuracy.A validity value extraction method from dynamic weighing was proposed.Then,an improved amplitude-limiting filtering algorithm and a BP neural networks model were developed to avoid accidental interference.The BP neural networks model used daily weight gain,day-age,average velocity,and the weight data after filtering algorithm as the input layer.The weighing system was tested in a commercial Beijing Fatty Chickens house with Beijing Fatty Chickens.We tested thirteen groups of Beijing Fatty Chickens of different weights,from 500 g to 1800 g in intervals of 100 g,using the three different methods:no filtering algorithm or BP neural networks,only the improved amplitude-limiting filtering algorithm and a hybrid of the improved amplitude-limiting filtering algorithm and BP neural networks.The results showed that the hybrid algorithm had a better performance in minimizing the error,lowering from the original 6%down to 3%.The accurate weight data was transmitted to the remote service platform for further decision-making,such as activity analysis,feeding management,and health alerts. 展开更多
关键词 Weighing of broiler chickens Improved amplitude-limiting filtering algorithm BP neural networks Dynamic weighing
Identification of the Worst-case Static Voltage Stability Margin Interval of AC/DC Power System Considering Uncertainty of Renewables 认领 引用 被引量：3
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作者 Wanbin Liu Shunjiang Lin +2 位作者 Yuerong Yang Mingbo Liu Qifeng Li 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2024年第3期974-987,共14页
Calculation of static voltage stability margin(SVSM)of AC/DC power systems with lots of renewable energy sources(RESs)integration requires consideration of uncertain load growth and renewable energy generation output.... Calculation of static voltage stability margin(SVSM)of AC/DC power systems with lots of renewable energy sources(RESs)integration requires consideration of uncertain load growth and renewable energy generation output.This paper presents a bi-level optimal power flow(BLOPF)model to identify the worst-case SVSM of an AC/DC power system with line commutation converter-based HVDC and multi-terminal voltage sourced converter-based HVDC transmission lines.Constraints of uncertain load growth’s hypercone model and control mode switching of DC converter stations are considered in the BLOPF model.Moreover,uncertain RES output fluctuations are described as intervals,and two three-level optimal power flow(TLOPF)models are established to identify interval bounds of the system worst-case SVSM.The two TLOPF models are both transformed into max–min bi-level optimization models according to independent characteristics of different uncertain variables.Then,transforming the inner level model into its dual form,max–min BLOPF models are simplified to single-level optimization models for direct solution.Calculation results on the modified IEEE-39 bus AC/DC case and an actual large-scale AC/DC case in China indicate correctness and efficiency of the proposed identification method. 展开更多
关键词 AC/DC power system control mode switching convex relaxation dual programming multi-level optimization optimal power flow static voltage stability margin
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Numerical investigation on effects of side curtain opening behavior on indoor climate of naturally ventilated dairy buildings 认领 引用 被引量：4
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作者 Qifeng Li Chuanxia Yao +4 位作者 Luyu Ding Ligen Yu Weihong Ma Ronghua Gao Wengang Zheng 《International Journal of Agricultural and Biological Engineering》 SCIE 2020年第5期63-72,共10页
The side-curtain is popular in cattle buildings to regulate indoor climates and ventilation rates by adjusting the opening ratio.It normally had three different adjusting strategies relate to the position of rollers,i... The side-curtain is popular in cattle buildings to regulate indoor climates and ventilation rates by adjusting the opening ratio.It normally had three different adjusting strategies relate to the position of rollers,i.e.central roller(S1),top roller(S2)and bottom roller(S3),which result in different opening behaviors to generate the same opening ratio but different opening positions in the side wall for a full-curtain house.Numerical simulations were conducted using computational fluid dynamics(CFD)to investigate the effects of the eight potential opening behaviors of side curtains on the indoor climates and airflow rates in winter for a typical naturally ventilated dairy house in China when the opening ratio were 8.5%and 17%.Airflow patterns,wind chilled temperature(WCT)and age of air were analyzed in the animal occupied zone(AOZ)by taking reference planes.Openings at the very bottom of side walls had more efficient ventilation due to the younger air age,more effective air disturbing,more uniformly distributed indicators in AOZ.However,it will result in a lower WCT in AOZ although a lower ventilation rate was observed in this case.Openings on the very top of side wall would generate a better thermal comfort in AOZ but with very poor air quality and nonuniformly distributed airflows in the dairy house.S1 was not recommended to the practical application due to the poor indoor climate and the higher cost of the mechanical structure.Based on the comprehensive evaluations of the analytic hierarchy process,the most satisfaction opening positions were at the bottom of the side curtains and the optimized adjusting strategy is S2. 展开更多
关键词 thermal comfort age of air ventilation rate computational fluid dynamics analytic hierarchy process
TGFN-SD:A text-guided multimodal fusion network for swine disease diagnosis 认领 引用 被引量：1
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作者 Gan Yang Qifeng Li +5 位作者 Chunjiang Zhao Chaoyuan Wang Hua Yan Rui Meng Yu Liu Ligen Yu 《Artificial Intelligence in Agriculture》 SCIE EI CSCD 2025年第2期266-279,共14页
China is the world's largest producer of pigs,but traditional manual prevention,treatment,and diagnosis methods cannot satisfy the demands of the current intensive production environment.Existing computer-aided di... China is the world's largest producer of pigs,but traditional manual prevention,treatment,and diagnosis methods cannot satisfy the demands of the current intensive production environment.Existing computer-aided diagnosis(CAD)systems for pigs are dominated by expert systems,which cannot be widely applied because the collection and maintenance of knowledge is difficult,and most of them ignore the effect of multimodal information.A swine disease diagnosis model was proposed in this study,the Text-Guided Fusion Network-Swine Diagnosis(TGFN-SD)model,which integrated text case reports and disease images.The model integrated the differences and complementary information in the multimodal representation of diseases through the text-guided transformer module such that text case reports could carry the semantic information of disease images for disease identification.Moreover,it alleviated the phenotypic overlap problem caused by similar diseases in combination with supervised learning and self-supervised learning.Experimental results revealed that TGFN-SD achieved satisfactory performance on a constructed swine disease image and text dataset(SDT6K)that covered six disease classification datasets with accuracy and F1-score of 94.48%and 94.4%respectively.The accuracies and F1-scores increased by 8.35%and 7.24%compared with those under the unimodal situation and by 2.02%and 1.63%compared with those of the optimal baseline model under the multimodal fusion.Additionally,interpretability analysis revealed that the model focus area was consistent with the habits and rules of the veterinary clinical diagnosis of pigs,indicating the effectiveness of the proposed model and providing new ideas and perspectives for the study of swine disease CAD. 展开更多
关键词 Computer-aided diagnosis Electronic health records Multimodal fusion Self-supervised learning Swine disease
Estimating the air exchange rates in naturally ventilated cattle houses using Bayesian-optimized GBDT 认领 引用 被引量：1
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作者 Luyu Ding Lei E +6 位作者 Yang Lyu Chunxia Yao Qifeng Li Shiwei Huang Weihong Ma Ligen Yu Ronghua Gao 《International Journal of Agricultural and Biological Engineering》 SCIE 2023年第1期73-80,共8页
It is challenging to estimate the air exchange rate(AER)dynamically in naturally ventilated livestock buildings such as dairy houses due to the influence of complex and variable outdoor environmental factors,large ope... It is challenging to estimate the air exchange rate(AER)dynamically in naturally ventilated livestock buildings such as dairy houses due to the influence of complex and variable outdoor environmental factors,large opening ratios,and the confusion of inflow and outflow at openings.This makes it difficult to efficiently regulate the opening ratio to meet the ventilation requirements in naturally ventilated livestock buildings.In this study,the air exchange rates of naturally ventilated cattle houses(NVCHs)in different seasons and opening ratios were obtained through field measurements and computational fluid dynamics(CFD)simulations.A fast and efficient machine learning framework was proposed and examined to predict AER based on the gradient boosting decision tree(GBDT)combined with Bayesian optimization.Compared with commonly used machine learning models such as multilayer perceptrons(MLPs)and support vector machines(SVMs),the proposed GBDT model has higher prediction accuracy and can avoid falling easily into local optima.Compared with the existing mechanical model based on the Bernoulli equation,the proposed GBDT model showed a slightly higher prediction than the mechanistic model and was much easier to use in AER estimation when inputting easily collected environmental factors in practical applications.Using Bayesian optimization could dramatically reduce the computing time when determining the optimal hyperparameter for establishing the GBDT model,dramatically saving on computing resources.Based on the Bayesian optimized GBDT model,the desirable opening ratio of the side curtain can be determined for automatically regulating the AER of cattle houses in future applications. 展开更多
关键词 natural ventilation Bayesian GBDT air exchange rate cattle house
A raw milk service platform using BP Neural Network and Fuzzy Inference 认领 引用 被引量：1
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作者 Weihong Ma Jinwei Fan +1 位作者 Qifeng Li Yuhang Tang 《Information Processing in Agriculture》 EI 2018年第3期308-319,共12页
An important index for raw milk storage in a dairy farm is the raw milk storage temperature which directly reflects the raw milk quality.Meanwhile,it’s hard to centrally manage numerous dairy farms which are not dist... An important index for raw milk storage in a dairy farm is the raw milk storage temperature which directly reflects the raw milk quality.Meanwhile,it’s hard to centrally manage numerous dairy farms which are not distributed in the same place.We aim to build a kind of raw milk monitoring and warning equipment,gateway and cloud service platform to solve these problems.The raw milk monitoring and warning equipment and service platform were designed to monitor the raw milk temperature in the refrigerated storage tank and provide a warning alarm if an exception occurred.Data-driven modeling was used for acquiring,cleaning,and utilizing data to solve the raw milk storage problems.The raw milk monitoring and warning management systemprovided away of predicting and warning for raw milk storage using BP Neural Network and Fuzzy Inference.The test showed that the BP Neural Network and Fuzzy Inference model built in this paper had a good performance in predicting the raw milk storage temperature and reflecting the variation of raw milk temperature in raw milk storage process.The platform and models provided a method to manage the raw milk in dairies and prevent the raw milk from deteriorating caused by the rising temperature. 展开更多
关键词 Raw milk service platform Raw milk temperature warning and predicting BP Neural Network Fuzzy Inference
Analysis and Optimization of Boost Converter Parameters in Internal Model Control for Voltage Source Converter-based AC Microgrids 认领 引用 被引量：1
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作者 Chiebuka Eyisi Qifeng Li 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2024年第5期2038-2054,共17页
This paper investigates integration of distributed energy resources(DERs)in microgrids(MGs)through two-stage power conversion structures consisting of DC-DC boost converter and DC-AC voltage source converter(VSC)subsy... This paper investigates integration of distributed energy resources(DERs)in microgrids(MGs)through two-stage power conversion structures consisting of DC-DC boost converter and DC-AC voltage source converter(VSC)subsystems.In contrast to existing investigations that treated DC-link voltage as an ideal constant voltage,this paper considers the non-ideal dynamic coupling between both subsystems for completeness and higher accuracy,which introduces additional DC-side dynamics to the VSC.The analysis shows parameters of the boost converter’s power model that impact stability through the DC-link.Carefully selecting these parameters can mitigate this effect on stability and improve dynamic performance across the DC-link.Hence,an optimization framework is developed to facilitate in selecting adequate boost converter parameters in designing a stable voltage source converter-based microgrid(VSC-MG).The developed optimization framework,based on particle swarm optimization,considers dynamic coupling between both subsystems and is also effective in avoiding inadequate boost converter parameters capable of propagating instability through the DC-link to the VSC.Simulations are performed with MATLAB/Simulink to validate theoretical analyses. 展开更多
关键词 AC microgrid boost converter dead-time droop control internal model control particle swarm optimization small-signal analysis time delay virtual impedance voltage source converter
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Hybrid Physics and Data-driven Contingency Filtering for Security Operation of Micro Energy-water Nexus 认领 引用
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作者 Mostafa Goodarzi Qifeng Li 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2023年第5期1820-1831,共12页
This paper investigates a novel engineering problem,i.e.,security-constrained multi-period operation of micro energywater nexuses.This problem is computationally challenging because of its high nonlinearity,nonconvexi... This paper investigates a novel engineering problem,i.e.,security-constrained multi-period operation of micro energywater nexuses.This problem is computationally challenging because of its high nonlinearity,nonconvexity,and large dimension.We propose a two-stage iterative algorithm employing a hybrid physics and data-driven contingency filtering(CF)method and convexification to solve it.The convexified master problem is solved in the first stage by considering the base case operation and binding contingencies set(BCS).The second stage updates BCS using physics-based data-driven methods,which include dynamic and filtered data sets.This method is faster than existing CF methods because it relies on offline optimization problems and contains a limited number of online optimization problems.We validate effectiveness of the proposed method using two different case studies:the IEEE 13-bus power system with the EPANET 8-node water system and the IEEE 33-bus power system with the Otsfeld 13-node water system. 展开更多
关键词 Contingency filtering micro energy-water nexus multi-period secure operation optimal power and water flow physics-guided data-driven
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