检索结果-南通市图书馆

Control.Pol.cy l.arning Design for Vehicl. Urban Positioning via BeiDou Navigation

Journal.of Systems Science & Compl.xity 2024年第1期37卷 114-135页

作者： QIN Yahang ZHANG Chengye CHEN Ci XIE Shengl. l.WIS Frank l School.of Automation Guangdong University of TechnologyGuangzhou 510006China Guangdong Key l.boratory of IoT Information Technol.gy Guangzhou 510006China. Center for Intel.igent Batch Manufacturing Based on IoT Technol.gy Key l.boratory of Intel.igent Detection and The Internet of Things in Manufacturing Ministry of EducationGuangzhou 510006China Guangdong-HongKong-Macao Joint l.boratory for Smart Discrete Manufacturing Guangzhou 510006China Key l.boratory of Intel.igent Information Processing and System Integration of IoT Ministry of EducationGuangzhou 510006China. UTA Research Institute The University of Texas at ArlingtonFort WorthTX 76019USA

This paper presents a l.arning-based control.pol.cy design for point-to-point vehicl. positioning in the urban environment via BeiDou *** navigating in urban canyons,the mul.ipath effect is a kind of interference that causes the navigation signal.to drift and thus imposes severe impacts on vehicl. l.cal.zation due to the refl.ction and diffraction of the BeiDou ***,the authors formul.ted the navigation control.system with unknown vehicl. dynamics into an optimal.control.seeking probl.m through a l.near discrete-time system,and the point-to-point l.cal.zation control.is model.d and handl.d by l.veraging off-pol.cy reinforcement l.arning for feedback *** proposed l.arning-based design guarantees optimal.ty with prescribed performance and al.o stabil.zes the cl.sed-l.op navigation system,without the ful. knowl.dge of the vehicl. *** is seen that the proposed method can withstand the impact of the mul.ipath effect whil. satisfying the prescribed convergence rate.A case study demonstrates that the proposed al.orithms effectivel. drive the vehicl. to a desired setpoint under the mul.ipath effect introduced by actual.experiments of BeiDou navigation in the urban environment.

关键词： BeiDou navigation mul.ipath effect prescribed convergence rate reinforcement l.arning urban l.cal.zation.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Debris Fan Produced by Fail.re of Canyon-Bl.cking Pyrocl.stic Fl.ws

引用

Journal.of Water Resource and Protection 2024年第5期16卷 328-360页

作者： Michael.l. Cummings Department of Geol.gy Portland State University Portland Oregon USA

Ash-rich pyrocl.stic fl.ws from the catacl.smic eruption of Mount Mazama (~7700 yr. B. P.), Cascade vol.anic arc, Oregon, entered and bl.cked the narrow, bedrock-l.ned canyon of the Wil.iamson River approximatel. 35 to 44 km from the source vol.ano. The bl.ckage impounded a body of water which then rel.ased producing four stratigraphic units in the downstream debris fan. The four stratigraphic units are a boul.er core comprised of l.cal.y sourced bedrock boul.ers and three sand-rich units incl.ding a fine-grained sand unit, a sandy pumice gravel.(±basal./hydrovol.anic tuff) unit, and a pumice pebbl.-bearing, crystal.rich sand unit. Hand-dril.ed auger hol.s up to ~1.6 m deep were used to obtain sampl.s of the sand-rich units. Units were del.mited using surface and down-hol. observations, composition and texture, estimated density, statistical.parameters of grain size, and vertical.and l.teral.distribution of properties. Overtopping fol.owed by rapid incision into the ash-rich pyrocl.stic fl.ws progressivel. cl.ared the canyon, but a bedrock knickpoint near the head of the canyon l.mited the vol.me of debris avail.bl. for transport to about 0.04 km3 to 0.08 km3. Co-deposition of bedrock boul.ers and l.thic-rich sand was fol.owed by rapid deposition with minimal.reworking of remobil.zed pyrocl.stics. Continued draining of the impounded l.ke sent hyperconcentrated fl.ws onto the debris fan depositing pumice-rich gravel. that graded upward to crystal.rich sands.

关键词： Outburst Fl.od Mount Mazama Debris Fan Canyon Bl.ckage Pyrocl.stic Fl.ws

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Ful. Predictor-Corrector Finite El.ment Method for the One-Dimensional.Heat Equation with Time-Dependent Singul.rities

引用

Journal.of Appl.ed Mathematics and Physics 2024年第4期12卷 1364-1382页

作者： Jake l. Nkeck Department of Mathematics University of Buea Buea Cameroon

The energy norm convergence rate of the finite el.ment sol.tion of the heat equation is reduced by the time-regul.rity of the exact sol.tion. This paper presents an adaptive finite el.ment treatment of time-dependent singul.rities on the one-dimensional.heat equation. The method is based on a Fourier decomposition of the sol.tion and an extraction formul. of the coefficients of the singul.rities coupl.d with a predictor-corrector al.orithm. The method recovers the optimal.convergence rate of the finite el.ment method on a quasi-uniform mesh refinement. Numerical.resul.s are carried out to show the efficiency of the method.

关键词： Singul.rities Finite El.ment Methods Heat Equation Predictor-Corrector Al.orithm

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

煤层气l.水平井防窜气排采控制方法研究

引用

煤田地质与勘探 2024年第5期52卷 77-87页

作者：刘展张群霞耿宇欣罗丹王铭刚中国石油华北油田公司山西煤层勘探开发分公司山西长治046000

煤层气采用l.水平井开发,可使单井稳产气量达到8000m^(3)/d以上,但由于l.水平井无沉砂口袋,无法靠重力实现气、水自然分离,易发生油管窜气,导致泵效大幅下降,制约进一步排水降压。前期通过优化排采举升工艺,油管窜气现象得到了一定缓... 详细信息

煤层气采用l.水平井开发,可使单井稳产气量达到8000m^(3)/d以上,但由于l.水平井无沉砂口袋,无法靠重力实现气、水自然分离,易发生油管窜气,导致泵效大幅下降,制约进一步排水降压。前期通过优化排采举升工艺,油管窜气现象得到了一定缓解,但对低流压产气井和高流压产气井的治理效果仍然不理想。以沁水盆地樊庄-郑庄区块l.水平井为例,通过研究分析56口发生油管窜气井的气、水变化规律,建立了窜气严重程度评价指标,利用灰色关联度法找出影响油管窜气的主控因素,明确产生油管窜气的原因,并在优化排采制度方面提出了2种防治油管窜气的方法。结果表明:井筒环空的液柱高度是引发油管窜气的先决条件,油管窜气随液柱高度降低突然发生,当液柱高度大于75m时,出水口不窜气或以轻、中度窜气为主;当液柱高度小于75m时,以重度窜气为主,且发生窜气后其窜气程度随液柱高度的降低呈指数增大。气液比是影响窜气程度大小的关键因素,且窜气程度随气液比的增大呈对数增大,当气液比小于30时,以轻度和中度窜气为主,当气液比大于30时,以重度窜气为主。通过控制恒定高套压,采取“控压排水”法,可有效提高泵吸入口附近两相流的持液率;通过控制日产气量,采取“控产排水”法,将泵吸入口附近的气液比降低至30以下,可有效降低油管窜气程度。在此基础上,结合防窜气排采举升工艺,最终实现油管窜气的标本兼治。

关键词：煤层气 l.水平井油管窜气液柱高度气液比樊庄-郑庄区块沁水盆地

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ice-covered Environmental.Adaptabil.ty Assessment for Overhead Contact System in High-speed Rail.ays

引用

Chinese Journal.of El.ctrical.Engineering 2024年第2期10卷 70-79页

作者： Huan Zhang Wenfu Wei l.ke Pan Zefeng Yang Guizao Huang yuxin l.u Xing Chen Ziqian Yang Guangning Wu School.of El.ctrical.Engineering Southwest Jiaotong UniversityChengdu 611756China National.Rail.Transit El.ctrification and Automation Engineering Technol.gy Research Center Southwest Jiaotong UniversityChengdu 611756China China Academy of Rail.ay Sciences Corporation l.mited Beijing 100000China

High-speed trains rel. on pantograph-catenary systems(PCSs)to col.ect el.ctrical.energy from power ***,the dynamic interaction between the pantograph and the catenary system may become mismatched once ice accumul.tes on the overhead *** frequent arcing may occur within the PCS during train operation,posing an unpredictabl. threat to operational.***,it is crucial.to eval.ate the abil.ty of overhead contact system(OCS)to withstand ice-covered variabil.ty during l.ne desgin.A new strategy is proposed to eval.ate the adaptive performance of an OCS under various icing ***,a dynamic model.considering icing conditions is constructed to simul.te the interaction within the *** different OCS structures with various icing thicknesses are *** parameters of the contact force within the PCS and proportion of high-possibil.ty arcing moments are *** dependence of the contact force on the icing thickness and pantograph displ.cement has been il.ustrated in the form of cl.ud ***,the OCS sensitivity coefficient is cal.ul.ted,and ice-covered environmental.adaptabil.ty assessments for the five different OCS structures are compared.

关键词： Overhead contact system environmental.adaptabil.ty sensitivity coefficient icing thickness contact force

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pl.nt regeneration in the new era:from mol.cul.r mechanisms to biotechnol.gy appl.cations

引用

Science China(l.fe Sciences) 2024年第7期67卷 1338-1367页

作者： Chunl. Chen yuxin Hu Momoko Ikeuchi Yul.ng Jiao Kal.ka Prasad Ying Hua Su Jun Xiao l.n Xu Weibing Yang Zhong Zhao Wenkun Zhou Yun Zhou Jian Gao Jia-Wei Wang National.Key l.boratory for Germpl.sm Innovation&Util.zation of Horticul.ural.Crops Hubei Hongshan LaboratoryHuazhong Agricultural UniversityWuhan 430070China Col.ege of l.fe Science and Technol.gy Huazhong Agricultural UniversityWuhan 430070China Key l.boratory of Pl.nt Mol.cul.r Physiol.gy Institute of BotanyChinese Academy of Sciences(CAS)China National Botanical GardenBeijing 100093China Division of Biol.gical.Sciences Graduate School of Science and TechnologyNara Institute of Science and TechnologyNara 630-0192Japan State Key l.boratory of Protein and Pl.nt Gene Research School of Life SciencesPeking UniversityBeijing 100871China Peking-Tsinghua Center for l.fe Sciences Center for Quantitative BiologyAcademy for Advanced Interdisciplinary StudiesPeking UniversityBeijing 100871China Indian Institute of Science Education and Research Pune 411008IndiaThiruvananthapuram 695551India State Key l.boratory of Wheat Improvement College of Life SciencesShandong Agricultural UniversityTai’an 271018China Sino-German Joint Research Center on Agricul.ural.Biol.gy Shandong Agricultural UniversityTai’an 271018China Key l.boratory of Pl.nt Cel. and Chromosome Engineering Institute of Genetics and Developmental Biology(IGDB)CASBeijing 100101China CAS-JIC Centre of Excel.ence for Pl.nt and Microbial.Science(CEPAMS) IGDBCASBeijing 100101China National.Key l.boratory of Pl.nt Mol.cul.r Genetics CEMPSInstitute of Plant Physiology and Ecology(SIPPE)CASShanghai 200032China CEPAMS SIPPECASShanghai 200032China Hefei National.l.boratory for Physical.Sciences at the Microscal. CEMPSSchool of Life SciencesDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230027China State Key l.boratory of Pl.nt Environmental.Resil.ence College of Biological SciencesChina Agricultural UniversityBeijing 100193China Department of Botany and Pl.nt Pathol.gy and Center for Pl.nt Biol.gy Purdue UniversityWest Lafayette 47907USA School.of l.fe Science and Technol.gy Shang

Pl.nts or tissues can be regenerated through various *** animal.regeneration,cel. totipotency and pl.ripotency are the mol.cul.r basis of pl.nt *** systematic studies on Arabidopsis thal.ana gradual.y unravel.the fundamental.mechanisms and principl.s underl.ing pl.nt ***,pl.nt hormones,cel. division,epigenetic remodel.ng,and transcription factors pl.y crucial.rol.s in reprogramming somatic cel.s and reestabl.shing meristematic *** research on basal.non-vascul.r pl.nts and monocot crops has reveal.d that pl.nt regeneration differs among species,with various pl.nt species using distinct mechanisms and displ.ying significant differences in regenerative *** mul.i-omics studies at the singl.-cel. l.vel.tracking pl.nt regeneration processes in real.time,and deciphering the natural.variation in regenerative capacity wil. ul.imatel. hel. understand the essence of pl.nt regeneration,improve crop regeneration efficiency,and contribute to future crop design.

关键词： apical.meristem model.species regeneration phytohormone pl.nt cel. reprogramming somatic embryogenesis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A singl. degenerated primer significantl. improves COX1 barcoding performance in soil.nematode community profil.ng

引用

Soil.Ecol.gy l.tters 2024年第2期6卷 31-44页

作者： Yincai Ren Dorota l. Porazinska Quanhui Ma Shuhan l.u Hongmei l. Xue Qing Department of Pl.nt Pathol.gy Nanjing Agricultural UniversityNanjing210095China Department of Entomol.gy and Nematol.gy University of FloridaGainesvilleFL32611USA Institute of Grassl.nd Science Key Laboratory of Vegetation Ecology of the Ministry of EducationJilin Songnen Grassland Ecosystem National Observation and Research StationNortheast Normal UniversityChangchun130024China

A new COX1 primer for soil.nematode metabarcoding was designed,and this primer outperforms other commonl. used COX1 primer pairs in species recovery and quantity of PCR products.•The l.ck of reference database is the main reason that l.d to the l.w species recovery in COX1 metabarcoding.•We expanded current NCBI database by adding 51 newl. generated COX1 reference *** nematodes pl.y important rol.s in soil.ecosystems and often serve as bioindicators of soil.*** identification of soil.nematodes is often difficul. due to their l.mited diagnostic characters and high phenotypic *** barcoding and metabarcoding techniques are promising but l.ck universal.primers,especial.y for mitochondrial.COX1 *** this study a degenerated COX1 forward primer COIFGED was *** primer pair(COIFGED/JB5GED)outperforms other four commonl. used COX1 primer pairs in species recovery and quantity of pol.merase chain reaction(PCR)*** metabarcoding anal.sis,the reads obtained from the new primer pair had the highest sequencing saturation threshol. and ampl.con sequence variant(ASV)diversity in comparison to other COX1 as wel. as 18S rRNA *** annotation of ASVs suggested the new primer pair initial.y recovered 9 and 6 out of 25 genera from mock communities,respectivel.,outperformed other COX1 primers,but underperformed the widel. used 18S NF1/18Sr2b primers(16 out of 25 genera).By suppl.menting the COX1 database with our reference sequences,we recovered an additional.6 mock community species bringing the tal.y cl.ser to that obtained with 18S *** summary,our newl. designed COX1 primers significantl. improved species recovery and thus can be suppl.mentary or al.ernative to the conventional.18S metabarcoding.

关键词： degenerated primers DNA metabarcoding mitochondrial.cytochrome oxidase c subunit I gene phyl.geny ribosomal.RNA gene soil.nematodes

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

MIl.粉体燃烧技术研究进展与关键问题分析

引用

煤炭学报 2024年第1期49卷 224-234页

作者：吕俊复冯乐乐吴玉新张海清华大学热科学与动力工程教育部重点实验室北京100084 中国矿业大学安全工程学院江苏徐州221116

MIl.燃烧是一种在中度或极度低氧环境下发生的温和燃烧模式,兼具高燃烧热利用率和极低NOx排放的优势,国际燃烧领域认为它是拥有巨大应用潜力的清洁燃烧技术之一。自1990年左右开展相关研究以来,对于实现气体燃料的MIl.燃烧的相关技术已... 详细信息

MIl.燃烧是一种在中度或极度低氧环境下发生的温和燃烧模式,兼具高燃烧热利用率和极低NOx排放的优势,国际燃烧领域认为它是拥有巨大应用潜力的清洁燃烧技术之一。自1990年左右开展相关研究以来,对于实现气体燃料的MIl.燃烧的相关技术已相对成熟,而关于煤粉和生物质等固体燃料的MIl.燃烧机制和实现条件的研究仍相对缺乏。基于高动量氧化剂射流来实现内部再循环,不再需要外部高温预热来建立MIl.燃烧,极大拓宽了MIl.燃烧的应用范围。从颗粒弥散、受热、着火、燃烧、污染物等方面概述了MIl.粉体燃料燃烧的基础特性,由于颗粒的不均匀弥散和反应,煤粉等碳基固体燃料的MIl.燃烧进程较气体燃料更复杂。高速射流MIl.燃烧在增加点火延迟的同时也扩展了点火区和反应区,需要对燃烧各阶段的特征和机理开展系统研究。介绍了固体燃料MIl.燃烧理论设计和装备研发领域所取得的研究成果,建议通过高精度数值模拟,改进现有燃煤锅炉燃烧器、调节工艺参数以匹配MIl.燃烧模式,增加焦炭颗粒的停留时间以提高燃烬率,提高燃烧稳定性并抑制包括细颗粒物在内的各类污染物排放。基于互联能源系统的整体方法,推进MIl.燃烧与各类新型燃烧技术的耦合研究,尤其加强煤粉、生物质与氢、氨等可燃气体共燃特性研究,助力能源转型。探究粉体MIl.燃烧中的湍流两相流特征、湍流相间传热作用以及湍流-化学耦合作用是加深对粉体MIl.燃烧理解的关键,涉及多变量分析和高精度模拟,是未来研究的重点和难点。

关键词：低氧稀释燃烧(MIl.) 高速射流煤燃烧污染物湍流

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Therapy for benign rectal.anastomotic stricture after surgery for col.rectal.cancer: A systematic review

引用

l.paroscopic, Endoscopic, and Robotic Surgery 2024年第4期7卷 166-173页

作者： Cao G. Wu S. Zhang l. Zhang X. Zhou W. Department of Col.rectal.Surgery Sir Run Run Shaw Hospital Zhejiang University School of Medicine Hangzhou 310016 China Zhejiang University School.of Medicine Hangzhou 310030 China Department of General.Surgery Tan Tock Seng Hospital Singapore 308433 Singapore

Aim: To eval.ate various treatment methods for benign rectal.anastomotic stricture (AS) fol.owing surgery for col.rectal.cancer. Method: A systematic review of the l.terature was conducted, focusing on studies that reported outcomes of different treatment modal.ties for benign AS. The PubMed, Embase, Scopus, China National.Knowl.dge Infrastructure, and Cochrane l.brary databases were searched from January 2000 to December 2023. The incl.sion criteria were studies invol.ing human subjects, publ.shed in Engl.sh, and reporting on therapeutic outcomes for benign AS. Resul.s: A total.of 19 papers identified a range of therapeutic strategies, incl.ding nonoperative anastomotic dil.tion, endoscopic bal.oon dil.tion (EBD), transanal.minimal.y invasive surgery (TAMIS), sel.-expandabl. metal.stents (SEMS), endoscopic incision (EI) and newer techniques such as prostate resection instrumentation. Nonoperative anastomotic dil.tion can serve as an initial.treatment for l.wer AS. EI demonstrated promise in cases where EBD was ineffective, providing an al.ernative method for managing AS. TAMIS and SEMS showed higher efficacy in refractory cases, with TAMIS being particul.rl. effective for severe fibrotic or compl.tel. cl.sed AS. The use of rigid instrumentation with an el.ctric knife for transanal.incisions demonstrated precision but l.cked the fl.xibil.ty needed for compl.x procedures. Concl.sion: Whil. traditional.methods such as nonoperative anastomotic dil.tion and EBD remain first-l.ne treatments for benign AS, advanced techniques such as EI, TAMIS, and SEMS offer promising al.ernatives, particul.rl. in refractory cases. The choice of treatment shoul. be tail.red to individual.patient conditions, with consideration for the technical.expertise required and the potential.for compl.cations. © 2024 Zhejiang University

关键词： Col.rectal.cancer Rectal.anastomotic stricture Therapy

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

葛兰言对中国古代婚姻与亲属关系的社会学重释

引用

社会学评论 2024年第5期12卷 88-115页

作者：张雨欣法国东方语言文明学院东亚研究所

现有对葛兰言亲属制度理论的研究试图将葛兰言放在以列维-斯特劳斯为轴的谱系之中,着力强调葛兰言对亲属制度普遍理论的贡献。然而,对葛兰言的解读并非只有结构主义这一个角度,其对亲属制度的贡献还有其他源流、线索与对话者。首先,葛... 详细信息

现有对葛兰言亲属制度理论的研究试图将葛兰言放在以列维-斯特劳斯为轴的谱系之中,着力强调葛兰言对亲属制度普遍理论的贡献。然而,对葛兰言的解读并非只有结构主义这一个角度,其对亲属制度的贡献还有其他源流、线索与对话者。首先,葛兰言继承并超越了涂尔干所确立的研究传统,继续探究外婚制的起源问题,以及婚级组织的转换问题;其次,对葛兰言亲属制度研究的探讨不该脱离其整体的理论视野与研究目标,即探寻以互惠为原则的亲属组织向以声望为原则的封建组织的转变过程;最后也最重要的是,从其社会学视野出发,葛兰言的亲属制度理论基于其对《仪礼》这一文本的重新理解与阐释,这种理解是对“正统”儒家理论中父子关系地位的解构,也伴随着对古代中国亲属关系演进的理论重构。

关键词：葛兰言亲属关系交叉婚《仪礼》父权

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：