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Mobile genetic elements facilitate the transmission of antibiotic resistance genes in multidrug-resistant Enterobacteriaceae from duck farms
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作者 Xin’er Zheng Dingting Xu +5 位作者 Jinchang Yan Min Qian Peng Wang Davood Zaeim Jianzhong Han Daofeng Qu 《Food Science and Human Wellness》 SCIE CSCD 2024年第2期729-735,共7页
Multidrug-resistant(MDR)Enterobacteriaceae critically threaten duck farming and public health.The phenotypes,genotypes,and associated mobile genetic elements(MGEs)of MDR Enterobacteriaceae isolated from 6 duck farms i... Multidrug-resistant(MDR)Enterobacteriaceae critically threaten duck farming and public health.The phenotypes,genotypes,and associated mobile genetic elements(MGEs)of MDR Enterobacteriaceae isolated from 6 duck farms in Zhejiang Province,China,were investigated.A total of 215 isolates were identified as Escherichia coli(64.65%),Klebsiella pneumoniae(12.09%),Proteus mirabilis(10.23%),Salmonella(8.84%),and Enterobacter cloacae(4.19%).Meanwhile,all isolates were resistant to at least two antibiotics.Most isolates carried tet(A)(85.12%),blaTEM(78.60%)and sul1(67.44%)resistance genes.Gene co-occurrence analysis showed that the resistance genes were associated with IS26 and integrons.A conjugative IncFII plasmid pSDM004 containing all the above MGEs was detected in Proteus mirabilis isolate SDM004.This isolate was resistant to 18 antibiotics and carried the blaNDM-5 gene.MGEs,especially plasmids,are the primary antibiotic resistance gene transmission route in duck farms.These findings provide a theoretical basis for the rational use of antibiotics in farms which are substantial for evaluating public health and food safety. 展开更多
关键词 Duck farm Mobile genetic element Antibiotic resistance gene PLASMID Food safety
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Enhancement Effects of Three Rare Earth Elements on the Growth of Chaetoceros Mulleri 被引量:1
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作者 Qu Keming(曲克明) +1 位作者 Xin Fuyan(辛福言) 《Marine Science Bulletin》 CAS 2001年第2期83-88,共6页
Enhancement effects of rare earth elements on the growth of Chaetoceros mulleri is studied in this paper. The results show that all of the light, middle and heavy rare earth elements have similar enhancement effect on... Enhancement effects of rare earth elements on the growth of Chaetoceros mulleri is studied in this paper. The results show that all of the light, middle and heavy rare earth elements have similar enhancement effect on the growth of Chaetoceros mulleri, with the beneficial concentrations of La, Gd and Yb being 7.28~87.40 μ mol/L, 6.36~57.23 μ mol/L and 5.78~17.34 μ mol/L. The optimum concentrations of La, Gd and Yb are 7.28 ~50.98 μ mol/L,31.80~44.52 μ m ol/L and 5.78~17.34 1μ mol/L, respectively. When the concentrations of La, Gd and Yb are 7.28~87.40 μ mol/L, 6.36~57.23 μ mol/L and 5.78~ 17,34 μ mol/L, the concentrations of chlorophyll have increased by 9.3~47.0%, 33.4~44.3%, and 36.5~40.3%, respectively as compared with the control group. The mechanism of enhancement of rare earth elements on the growth ot Chaetoceros mulleri is also discussed in this paper. 展开更多
关键词 RARE EARTH element CHAETOCEROS mulleri enhancEMENT
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Interaction between the Wilms tumour factor-1 element in the promoter of Amh and a downstream enhancer is required for a strong expression of the gene in pre-pubertal sertoli cells 被引量:1
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作者 David W. Dresser 《American Journal of Molecular Biology》 2013年第3期165-172,共8页
Amh (anti-Müllerian hormone) is a single copy gene which is expressed strongly in Sertoli cells in the foetal testis and participates in the onset of sexual differentiation. Its promoter driving the expression of... Amh (anti-Müllerian hormone) is a single copy gene which is expressed strongly in Sertoli cells in the foetal testis and participates in the onset of sexual differentiation. Its promoter driving the expression of a reporter gene (d2EGFP) has been used to analyse the role of certain defined putative elements and a downstream enhancer element in gene expression. These experiments were carried out in vitro using a line of pre-pubertal mouse Sertoli cells, transienly transfected with circular DNA constructs with variously mutated promoter elements. A downstream enhancer element, situated immediately 3’ of the polyadenylation (PA) signal for Amh, has been inserted in an equivalent position in the d2EGFP construct. When the Amh promoter is unmodified, the downstream enhancer (DE) is positively associated with a large increase in EGFP expression. This is at least partly the consequence of an increased rate of expression by individual cells. Experiments using variously truncated Amh promoters indicate that an upstream region (-214 to -336) may play a minor role in facilitating enhancement. However mutation of the Wilms tumour factor-1 element, situated between the tata box and the start of translation, results in an almost complete suppression of enhancement. 展开更多
关键词 Mouse Cell Lines In Vitro AMH PROMOTER SMAT Pre-Pubertal Sertoli DOWNSTREAM enhancer Wilms Tumour Factor element
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Dynamic finite element model updating using meta-model and genetic algorithm 被引量:3
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作者 费庆国 李爱群 缪长青 《Journal of Southeast University(English Edition)》 EI CAS 2006年第2期213-217,共5页
Current dynamic finite element model updating methods are not efficient or restricted to the problem of local optima. To circumvent these, a novel updating method which integrates the meta-model and the genetic algori... Current dynamic finite element model updating methods are not efficient or restricted to the problem of local optima. To circumvent these, a novel updating method which integrates the meta-model and the genetic algorithm is proposed. Experimental design technique is used to determine the best sampling points for the estimation of polynomial coefficients given the order and the number of independent variables. Finite element analyses are performed to generate the sampling data. Regression analysis is then used to estimate the response surface model to approximate the functional relationship between response features and design parameters on the entire design space. In the fitness evaluation of the genetic algorithm, the response surface model is used to substitute the finite element model to output features with given design parameters for the computation of fitness for the individual. Finally, the global optima that corresponds to the updated design parameter is acquired after several generations of evolution. In the application example, finite element analysis and modal testing are performed on a real chassis model. The finite element model is updated using the proposed method. After updating, root-mean-square error of modal frequencies is smaller than 2%. Furthermore, prediction ability of the updated model is validated using the testing results of the modified structure. The root-mean-square error of the prediction errors is smaller than 2%. 展开更多
关键词 finite element model model updating response surface model genetic algorithm
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Construction of retroviral vector carrying HSV tk gene under control of human AFP enhancer core sequence and human pgk promotor * 被引量:1
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作者 高军 曹广文 +5 位作者 戚中田 仇小芳 吴宗娣 杜平 杨文国 崔龙 《World Journal of Gastroenterology》 SCIE CAS CSCD 1997年第1期14+12-13,12-13,共3页
AIM Tenstruct retroviral vector bringing HSV tk gene under control by human AFP enhancer core sequence and human pgk promotor.
关键词 Liver neoplasms\ \ Simplexvirus\ \ Retroviridae\ \ alpha fetoproteins enhancer elements (genetics)\ \ Gene therapy
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Chemical characteristics of aerosols at coastal station in Hong Kong.Ⅱ. Environmental behavior of trace elements during the April 1995 to April 1996 被引量:3
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作者 K.S.Lam Z.L.Cheng +1 位作者 S.C.Kot C.W.Tsang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2004年第2期212-221,共10页
An one-year of sampling aerosol program was carried out during the period of April 1995 to April 1996 at coastal region, Cape D′Aguilar, in Hong Kong. The trace element composition of aerosol particles(TSP and PM ... An one-year of sampling aerosol program was carried out during the period of April 1995 to April 1996 at coastal region, Cape D′Aguilar, in Hong Kong. The trace element composition of aerosol particles(TSP and PM 10 ) were measured and analyzed by using the Instrumental Neutron Activation Analysis(INAA) and Inductive Couple Plasma-Mass Spectrometry(ICP-MS) techniques. The results showed that the polluted elements such as: V, Zn, As, Pb, Cd, Sb, I, Se, Bi, with high enrichment factor(E.F) values, are derived from anthropogenic sources, while Sc, Al, Fe, Mn, Sm, La, Sr are less than 10 in E.F, these elements are related the crust and soil. The concentration of the trace elements are present seasonal variation i.e. summer low and winter high, whereas the V or noncrustal V(V *) present summer high and winter low, this phenomenon might be explained by local or regional oil combustion sources. Use three type of elemental ratio, e.g. La/Sm, Mn */V * and Bi/Al indicate that both TSP and PM 10 of La/Sm ratios are mainly related to soil and dust, Mn */V * are probably represent fossil combustion and Bi/Al are possibly associated with refuse incineration, ferromanganese alloys and aluminum production. The varimax rotation factor analysis for trace elements was performed. By means of the absolute principal component analysis(APCA) and multiple regression, the contribution of trace elements to possible sources and overall means of trace elements were estimated. The results showed that the present station is impacted by the anthropogenic species, although the quantities are different during the summertime and wintertime. 展开更多
关键词 TSP PM 10 trace elements enhancement factor element ratios seasonal variation factor analysis
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Recent Advances in Sorghum Genetic Enhancement Research at ICRISAT 被引量:2
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作者 Are Ashok Kumar Belum Venkata Subba Reddy +4 位作者 Hari Chand Sharma Charles Thomas Hash Pinnamaneni Srinivasa Rao Bhavanasi Ramaiah Pulluru Sanjana Reddy 《American Journal of Plant Sciences》 2011年第4期589-600,共12页
Sorghum is one of the most important cereal crops widely grown for food, feed, fodder/forage, and fuel in the semi-arid tropics of Asia, Africa, the Americas and Australia. The global sorghum areas remained static as ... Sorghum is one of the most important cereal crops widely grown for food, feed, fodder/forage, and fuel in the semi-arid tropics of Asia, Africa, the Americas and Australia. The global sorghum areas remained static as the increased area in Africa compensated the area loss in Asia. In spite of rapid decline in sorghum area in Asia due to competition from other remunerative crops, sorghum grain production levels have not declined at the same rate owing to adoption of high yielding hybrids. Though impressive gains have been made in improving productivity levels, biotic and abiotic challenges such as shoot fly, stem borer, grain molds, and terminal drought stress continue to haunt the sorghum growers across the world. International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and the respec-tive national programs are working on genetic enhancement of sorghum for high yield;shoot fly, and grain mold resis-tance, and sweet stalk traits. In addition, research focus at ICRISAT also includes adaptation to postrainy season, ter-minal drought tolerance, and increasing micronutrient contents (Fe and Zn) in grain. Genetic and cytoplasmic diversi-fication of hybrid parents and varieties for key traits are critical for sustaining the productivity gains. The grain and stover quality requirements of different market segments needs special attention in sorghum improvement research to enhance its market value. This paper analyses the progress made in sorghum improvement research at ICRISAT in partnership with national programs in recent years and the way forward. 展开更多
关键词 ICRISAT SORGHUM genetic enhancement GRAIN Yield SHOOT FLY GRAIN Mold Drought BIOFORTIFICATION
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Genetic algorithm-finite element method inversion of the factors determining the recent tectonic stress field of part of East Asia area
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作者 安美建 石耀霖 李方全 《Acta Seismologica Sinica(English Edition)》 EI CSCD 1998年第3期1-8,共8页
Genetic algorithm finite element method (GA FEM) is applied to the study of tectonic stress field of part of East Asia area. From the observed stress distribution, 2 D elastic plane stress inversion is made to dedu... Genetic algorithm finite element method (GA FEM) is applied to the study of tectonic stress field of part of East Asia area. From the observed stress distribution, 2 D elastic plane stress inversion is made to deduce the boundary forces and investigate controlling factors. It is suggested that the continent continent collision is the dominant factor controlling the Chinese tectonic stress field. The ocean continent convergence along the subduction zone is an important factor. There exists tensile boundary force along the marginal sea. 展开更多
关键词 genetic algorithm finite element method (GA FEM) tectonic stress field dynamic genetic algorithm inversion of finite element method
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Optimizing Data Collection Path in Sensor Networks with Mobile Elements
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作者 Liang He Zhi Chen Jing-Dong Xu 《International Journal of Automation and computing》 EI 2011年第1期69-77,共9页
Exploiting mobile elements (MEs) to accomplish data collection in wireless sensor networks (WSNs) can improve the energy efficiency of sensor nodes, and prolong network lifetime. However, it will lead to large dat... Exploiting mobile elements (MEs) to accomplish data collection in wireless sensor networks (WSNs) can improve the energy efficiency of sensor nodes, and prolong network lifetime. However, it will lead to large data collection latency for the network, which is unacceptable for data-critical applications. In this paper, we address this problem by minimizing the traveling length of MEs. Our methods mainly consist of two steps: we first construct a virtual grid network and select the minimal stop point set (SPS) from it; then, we make optimal scheduling for the MEs based on the SPS in order to minimize their traveling length. Different implementations of genetic algorithm (GA) are used to solve the problem. Our methods are evaluated by extensive simulations. The results show that these methods can greatly reduce the traveling length of MEs, and decrease the data collection latency. 展开更多
关键词 Mobile element data collection genetic algorithm sensor network data latency.
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Parentage determination of black sea bream(Acanthopagrus schlegelii)for stock enhancement:effectiveness and loss of genetic variation
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作者 Binbin Shan Yan Liu +4 位作者 Na Song Changping Yang Shengnan Liu Tianxiang Gao Dianrong Sun 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第6期41-49,共9页
The stock enhancement programs for black sea bream Acanthopagrus schlegelii have been conducted in China for a fewyears.However,little information has been reported concerning the effectiveness and genetic effect of b... The stock enhancement programs for black sea bream Acanthopagrus schlegelii have been conducted in China for a fewyears.However,little information has been reported concerning the effectiveness and genetic effect of black sea bream stock enhancement.In order to detect the contribution of released individuals in Zhujiang River Estuary(ZRE)and Daya Bay(DB),six microsatellite markers were used to identify the hatchery-released individuals.In addition,this pedigree of hatchery populations(broodfish and hatchery-released offspring)was traced to detect the number of effective parents(N_(e)),the inbreeding coefficient and the decrease of genetic variability in the reproduction.The pedigree reconstruction showed that at least 69(out of 93)broodfish had offspring.The estimated N_(e) was 54.8,consequently the inbreeding coefficient was 0.91%.The genetic diversity of hatchery-released offspring was lower than that in that of broodfish(heterozygosity alleles,0.727-0.774),some alleles(number of alleles,61-69)and genetic variance were lost during reproduction.It was observed that wild samples had higher levels of genetic diversity compared with hatchery populations as well as recaptured samples in releasing area.A total of 128 hatchery-released black sea bream were identified among 487 recaptured samples in ZRE,while a total of 15 samples were identified among 96 samples in DB.In summary,there was a high survival of released fish.N_(e)vertheless,the results provided evidence to consider a loss of genetic variation in hatcheryreleased stock and a negative genetic effect of the stock enhancement. 展开更多
关键词 Acanthopagrus schlegelii stock enhancement effectiveness microsatellite maker genetic effect pedigree of hatchery populations
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Bandwidth-enhanced dual-polarized antenna with improved broadband integrated balun and distributed parasitic element
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作者 Fu Suidao Cao Zhenxin +2 位作者 Gao Di Chen Peng Xu Changzhi 《Journal of Southeast University(English Edition)》 EI CAS 2020年第4期367-375,共9页
A bandwidth-enhanced dual-polarized antenna is proposed for 2/3/4/5G applications,which is composed of distributed parasitic elements(DPEs),a main radiator,two improved broadband integrated baluns and a reflector.Firs... A bandwidth-enhanced dual-polarized antenna is proposed for 2/3/4/5G applications,which is composed of distributed parasitic elements(DPEs),a main radiator,two improved broadband integrated baluns and a reflector.First,a novel tooth-shape shorted slot line in the improved broadband integrated balun is analyzed to adjust the input impedance of the antenna.Then,DPEs with 2×2 circular plates loading over the main radiator are proposed to improve broadband impedance matching and radiation pattern.By utilizing impedance compensation of the tooth-shaped shorted slot line and the electromagnetic induction of the DPEs,the antenna achieves an enhanced impedance bandwidth and a stable radiation pattern.To verify these ideas,the bandwidth-enhanced dual-polarized antenna was fabricated and measured.The experimental results indicate that the proposed antenna achieves an operating bandwidth of 72.2%(1.69 to 3.60 GHz)with a return loss(RL)less than-15 dB and a port-to-port isolation(ISO)larger than 30 dB.The antenna obtains a half-power beamwidth(HPBW)within(66±5)°and a gain within(9.0±0.6)dBi in the 2/3/4G bands,and an HPBW within(61.5±2.5)°and a gain within(9.8±0.3)dBi in the 5G band.Across the whole band,the cross-polarization discrimination(XPD)and the front-to-back ratio are both larger than 20 dB. 展开更多
关键词 dual-polarized antenna bandwidth enhancement integrated balun distributed parasitic elements impedance matching
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Clay minerals and elemental composition of sediments on different sedimentary units in the northern East China Sea shelf:provenance tracing and genetic mechanism analysis
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作者 Xiaoyan Xu Yong Zhang +6 位作者 Yanguang Dou Jingyi Cong Beibei Mi Xiaohui Chen Xia Li Chengfen Xu Yongyu Ye 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第11期19-34,共16页
The composition,provenance,and genetic mechanism of sediment on different sedimentary units of the East China Sea(ECS)shelf are essential for understanding the depositional dynamics environment in the ECS.The sediment... The composition,provenance,and genetic mechanism of sediment on different sedimentary units of the East China Sea(ECS)shelf are essential for understanding the depositional dynamics environment in the ECS.The sediments in the northern ECS shelf are distributed in a ring-shaped distribution centered on the southwestern Cheju Island Mud.From the inside to the outside,the grain size goes from fine to coarse.Aside from the“grain size effect”,hydrodynamic sorting and mineral composition are important restrictions on the content of rare earth elements(REEs).Based on the grain size,REEs,and clay mineral composition of 300 surface sediments,as well as the sedimentary genesis,the northern ECS shelf is divided into three geochemical zones:southwestern Cheju Island Mud Area(ZoneⅠ),Changjiang Shoal Sand Ridges(ZoneⅡ-1),Sand Ridges of the East China Sea shelf(ZoneⅡ-2).The northern ECS shelf is mostly impacted by Chinese mainland rivers(the Changjiang River and Huanghe River),and the provenance and transport mechanism of sediments of different grain sizes is diverse.The bulk sediments come primarily from the Changjiang River,with some material from the Huanghe River carried by the Yellow Sea Coastal Current and the North Jiangsu Coastal Current,and less from Korean rivers.Among them,surface sediments in the southwestern Cheju Island Mud Area(ZoneⅠ)come mostly from the Changjiang River and partly from the Huanghe River.It was formed by the counterclockwise rotating cold eddies in the northern ECS shelf,which caused the sedimentation and accumulation of the fine-grained sediments of the Changjiang River and the Huanghe River.The Changjiang Shoal Sand Ridges(ZoneⅡ-1)were developed during the early-middle Holocene sea-level highstand.It is the modern tidal sand ridge sediment formed by intense hydrodynamic action under the influence of the Yellow Sea Coastal Current,North Jiangsu Coastal Current,and Changjiang Diluted Water.The surface sediments mainly originate from the Changjiang River and Huanghe River,with the Changjiang River dominating,and the Korean River(Hanjiang River)influencing just a few stations.Sand Ridges of the East China Sea shelf(ZoneⅡ-2)are the relict sediments of the paleo-Changjiang River created by sea invasion at the end of the Last Deglaciation in the Epipleistocene.The clay mineral composition of the surface sediments in the study area is just dominated by the Changjiang River,with the North Jiangsu Coastal Current and the Changjiang Diluted Water as the main transporting currents. 展开更多
关键词 the northern East China Sea shelf rare earth element clay mineral PROVENANCE genetic mechanism
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Biodiversity of Indian Germplasm of Cotton and Its Use for Genetic Enhancement
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作者 MAYEE C D KRANTHI K R 《棉花学报》 CSCD 北大核心 2008年第S1期14-,共1页
Cotton production in India was stagnant at 12.3 to 17.7 million bales over the decade 1992-2003.The introduction of new technologies during the early part of the decade,notably Bt-cotton technology,hybrids,
关键词 maps Biodiversity of Indian Germplasm of Cotton and Its Use for genetic enhancement
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Finding an optimization of the plate element of Egyptian research reactor using genetic algorithm
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作者 WAHED Mohamed IBRAHIM Wesam EFFAT Ahmed 《Nuclear Science and Techniques》 SCIE CAS CSCD 2008年第5期314-320,共7页
The second Egyptian research reactor ET-RR-2 went critical on the 27th of November 1997.The National Center of Nuclear Safety and Radiation Control (NCNSRC) has the responsibility of the evaluation and assessment of t... The second Egyptian research reactor ET-RR-2 went critical on the 27th of November 1997.The National Center of Nuclear Safety and Radiation Control (NCNSRC) has the responsibility of the evaluation and assessment of the safety of this reactor.The purpose of this paper is to present an approach to optimization of the fuel element plate. For an efficient search through the solution space we use a multi objective genetic algorithm which allows us to identify a set of Pareto optimal solutions providing the decision maker with the complete spectrum of optimal solutions with respect to the various targets.The aim of this paper is to propose a new approach for optimizing the fuel element plate in the reactor.The fuel element plate is designed with a view to improve reliability and lifetime and it is one of the most important elements during the shut down.In this present paper,we present a conceptual design approach for fuel element plate,in conjunction with a genetic algorithm to obtain a fuel plate that maximizes a fitness value to optimize the safety design of the fuel plate. 展开更多
关键词 埃及核反应堆 遗传算法 燃料元件 核技术
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An improved optimal elemental method for updating finite element models 被引量:5
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作者 段忠东 Spencer B.F. +1 位作者 闫桂荣 欧进萍 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2004年第1期67-74,共8页
The optimal matrix method and optimal elemental method used to update finite element models may not provide accurate results.This situation occurs when the test modal model is incomplete,as is often the case in practi... The optimal matrix method and optimal elemental method used to update finite element models may not provide accurate results.This situation occurs when the test modal model is incomplete,as is often the case in practice.An improved optimal elemental method is presented that defines a new objective function,and as a byproduct,circumvents the need for mass normalized modal shapes,which are also not readily available in practice.To solve the group of nonlinear equations created by the improved optimal method,the Lagrange multiplier method and Matlab function fmincon are employed.To deal with actual complex structures, the float-encoding genetic algorithm(FGA)is introduced to enhance the capability of the improved method.Two examples,a 7- degree of freedom(DOF)mass-spring system and a 53-DOF planar frame,respectively,are updated using the improved method. The example results demonstrate the advantages of the improved method over existing optimal methods,and show that the genetic algorithm is an effective way to update the models used for actual complex structures. 展开更多
关键词 model updating optimal elemental method Lagrangc multiplier method genetic algorithm
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Enhancement of natural convection heat transfer from a fin by triangular perforation of bases parallel and toward its tip 被引量:3
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作者 Abdullah H.AlEssa Mohamad I.Al-Widyan 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第8期1033-1044,共12页
This study examines the heat transfer enhancement from a horizontal rectangular fin embedded with triangular perforations (their bases parallel and toward the fin tip) under natural convection. The fin's heat dissi... This study examines the heat transfer enhancement from a horizontal rectangular fin embedded with triangular perforations (their bases parallel and toward the fin tip) under natural convection. The fin's heat dissipation rate is compared to that of an equivalent solid one. The parameters considered are geometrical dimensions and thermal properties of the fin and the perforations. The gain in the heat transfer enhancement and the fin weight reduction due to the perforations are considered. The study shows that the heat dissipation from the perforated fin for a certain range of triangular perforation dimensions and spaces between perforations result in improvement in the heat transfer over the equivalent solid fin. The heat transfer enhancement of the perforated fin increases as the fin thermal conductivity and its thickness are increased. 展开更多
关键词 finned surfaces heat transfer enhancement triangular perforations natural convection finite element perforated fin heat dissipation
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Multi-objective optimization of stamping forming process of head using Pareto-based genetic algorithm 被引量:10
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作者 周杰 卓芳 +1 位作者 黄磊 罗艳 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3287-3295,共9页
To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based gen... To obtain the optimal process parameters of stamping forming, finite element analysis and optimization technique were integrated via transforming multi-objective issue into a single-objective issue. A Pareto-based genetic algorithm was applied to optimizing the head stamping forming process. In the proposed optimal model, fracture, wrinkle and thickness varying are a function of several factors, such as fillet radius, draw-bead position, blank size and blank-holding force. Hence, it is necessary to investigate the relationship between the objective functions and the variables in order to make objective functions varying minimized simultaneously. Firstly, the central composite experimental(CCD) with four factors and five levels was applied, and the experimental data based on the central composite experimental were acquired. Then, the response surface model(RSM) was set up and the results of the analysis of variance(ANOVA) show that it is reliable to predict the fracture, wrinkle and thickness varying functions by the response surface model. Finally, a Pareto-based genetic algorithm was used to find out a set of Pareto front, which makes fracture, wrinkle and thickness varying minimized integrally. A head stamping case indicates that the present method has higher precision and practicability compared with the "trial and error" procedure. 展开更多
关键词 stamping forming HEADS finite element analysis central composite experimental design response surface methodology multi-objective genetic algorithm
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Optimization of Bearing Locations for Maximizing First Mode Natural Frequency of Motorized Spindle-Bearing Systems Using a Genetic Algorithm 被引量:4
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作者 Chi-Wei Lin 《Applied Mathematics》 2014年第14期2137-2152,共16页
This paper has developed a genetic algorithm (GA) optimization approach to search for the optimal locations to install bearings on the motorized spindle shaft to maximize its first-mode natural frequency (FMNF). First... This paper has developed a genetic algorithm (GA) optimization approach to search for the optimal locations to install bearings on the motorized spindle shaft to maximize its first-mode natural frequency (FMNF). First, a finite element method (FEM) dynamic model of the spindle-bearing system is formulated, and by solving the eigenvalue problem derived from the equations of motion, the natural frequencies of the spindle system can be acquired. Next, the mathematical model is built, which includes the objective function to maximize FMNF and the constraints to limit the locations of the bearings with respect to the geometrical boundaries of the segments they located and the spacings between adjacent bearings. Then, the Sequential Decoding Process (SDP) GA is designed to accommodate the dependent characteristics of the constraints in the mathematical model. To verify the proposed SDP-GA optimization approach, a four-bearing installation optimazation problem of an illustrative spindle system is investigated. The results show that the SDP-GA provides well convergence for the optimization searching process. By applying design of experiments and analysis of variance, the optimal values of GA parameters are determined under a certain number restriction in executing the eigenvalue calculation subroutine. A linear regression equation is derived also to estimate necessary calculation efforts with respect to the specific quality of the optimization solution. From the results of this illustrative example, we can conclude that the proposed SDP-GA optimization approach is effective and efficient. 展开更多
关键词 Optimal DESIGN Motorized SPINDLE System DESIGN Finite element Method genetic Algorithm FIRST MODE Natural Frequency
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Fluorescence and cofluorescence enhancement of Tb(Ⅲ) complexes with pyromellitic acid by M (M = Gd, La, Ca, and Sr ions) 被引量:1
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作者 WANGZhengxiang CHENHong +2 位作者 SHUWangen ZHAODongbai ZHOUZhongcheng 《Rare Metals》 SCIE EI CAS CSCD 2004年第1期32-37,共6页
Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes werestudied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. Thecofluorescence enhancement, a result of ligan... Fluorescence and cofluorescence properties of Tb(Ⅲ) solid complexes werestudied using pyromellitic acid (PMA) as ligand and fluorescence inert ions as doping elements. Thecofluorescence enhancement, a result of ligand sensitized fluorescence, was observed in Tb(Ⅲ) solidcomplexes doped with fluorescent inert ions La(Ⅲ), Gd(Ⅲ), Ca(Ⅲ), and Sr(Ⅲ). The effect of thetype and content of doping elements on fluorescence enhancement was studied, and optimum conditionswere determined. The results show that Gd (La, Ca, Sr) has clear cofluorescence effect in solidcomplex Tb-M-PMA system, and in present work, rare earth complex fluorescent powder that emitsbright green fluorescence at ultraviolet excitation was obtained, which had potential application asfluorescent anti-counterfeit ink. 展开更多
关键词 fluorescence enhancement COFLUORESCENCE doping elements TERBIUM pyromellitic acid
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Element yield rate prediction in ladle furnace based on improved GA-ANFIS 被引量:3
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作者 徐喆 毛志忠 《Journal of Central South University》 SCIE EI CAS 2012年第9期2520-2527,共8页
The traditional prediction methods of element yield rate can be divided into experience method and data-driven method.But in practice,the experience formulae are found to work only under some specific conditions,and t... The traditional prediction methods of element yield rate can be divided into experience method and data-driven method.But in practice,the experience formulae are found to work only under some specific conditions,and the sample data that are used to establish data-driven models are always insufficient.Aiming at this problem,a combined method of genetic algorithm(GA) and adaptive neuro-fuzzy inference system(ANFIS) is proposed and applied to element yield rate prediction in ladle furnace(LF).In order to get rid of the over reliance upon data in data-driven method and act as a supplement of inadequate samples,smelting experience is integrated into prediction model as fuzzy empirical rules by using the improved ANFIS method.For facilitating the combination of fuzzy rules,feature construction method based on GA is used to reduce input dimension,and the selection operation in GA is improved to speed up the convergence rate and to avoid trapping into local optima.The experimental and practical testing results show that the proposed method is more accurate than other prediction methods. 展开更多
关键词 genetic algorithm adaptive neuro-fuzzy inference system ladle furnace element yield rate PREDICTION
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