检索结果-南通市图书馆

Study on the clogging mechanism of punching screen in sand control by the punching structure parameters

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第1期21卷 609-620页

作者： fu-cheng Deng fu-Lin Gui Bai-Tao Fan Lei Wen Sheng-Hong Chen Ning Gong Yun-Chen Xiao Zhi-Hui Xu Yangtze University Jingzhou434023HubeiChina CNOOC Research Institute Ltd. Beijing100028China CNOOC Ener Tech-Drilling&Production Co. Tianjin300457China Tianjin Branch of CNOOC Ltd. Tianjin300459China

As an independent sand control unit or a common protective shell of a high-quality screen,the punching screen is the outermost sand retaining unit of the sand control pipe which is used in geothermal well or oil and gas ***,most screens only consider the influence of the internal sand retaining medium parameters in the sand control performance design while ignoring the influence of the plugging of the punching screen on the overall sand retaining performance of the *** explore the clogging mechanism of the punching screen,this paper established the clogging mechanism calculation model of a single punching screen sand control unit by using the computational fluid mechanics-discrete element method(CFD-DEM)combined *** to the combined motion of particles and fluids,the influence of the internal flow state on particle motion and accumulation was *** results showed that(1)the clogging process of the punching sand control unit is divided into three stages:initial clogging,aggravation of clogging and stability of *** the initial stage of blockage,coarse particles form a loose bridge structure,and blockage often occurs preferentially at the streamline gathering place below chamfering inside the sand control *** the stage of blockage intensification,the particle mass develops into a relatively complete sand bridge,which develops from both ends of the opening to the center of the *** the stable plugging stage,the sand deposits show a“fan shape”and form a“V-shaped”gully inside the punching slot element.(2)Under a certain reservoir particle-size distribution,The slit length and opening height have a large influence on the permeability and blockage rate,while the slit width size has little influence on the permeability and blockage *** microscopic clogging mechanism and its law of the punching screen prevention unit are proposed in this study,which has some field guidance significance for the design of punching screen

关键词： Punching screen Plugging CFD-DEM Size parameter Sand control

Static recrystallization behaviors and mechanisms of 7Mo super-austenitic stainless steel with undissolved sigma precipitates during double-stage hot deformation

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第2期31卷 475-487页

作者： Shi-guang Xu Jin-shan He Run-ze Zhang fu-cheng Zhang Xi-tao Wang Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing100083China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao066004HebeiChina Shandong Provincial Key Laboratory for High Strength Lightweight Metallic Materials Advanced Materials InstituteQilu University of Technology(Shandong Academy of Science)Jinan250353ShandongChina

Static recrystallization(SRX)behaviors and corresponding recrystallization mechanisms of 7Mo super-austenitic stainless steel were studied under different deformation *** order of influence of deformation parameters on static recrystallization behaviors,from high to low,is followed by temperature,first-stage strain and strain ***,the effect of holding time on static recrystallization behaviors is significantly controlled by *** addition,with the increase in temperature from 1000 to 1200°C,the static recrystallization mechanism evolves from discontinuous static recrystallization and continuous static recrystallization(cSRX)to metadynamic recrystallization and cSRX,and finally to *** cSRX exists at all *** is because high stacking fault energy(56 mJ m−2)promotes the movement of dislocations,making the deformation mechanism of this steel is dominated by planar slip of *** undissolved sigma precipitates promote static recrystallization through particle-stimulated ***,small strain-induced precipitates at grain boundaries hinder the nucleation of conventional SRX and the growth of recrystallized grains,while the hindering effect decreases with the increase in temperature.

关键词： 7Mo super-austenitic stainless steel Double-stage hot deformation Conventional static recrystallization Metadynamic recrystallization Strain-induced precipitation

Differences and identification on multi-time hydrocarbon generation of carboniferous-permian coaly source rocks in the Huanghua Depression,Bohai Bay Basin

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 765-776页

作者： Jin-Jun Xu Xian-Gang cheng Shu-Nan Peng Jun-Cai Jiang Qi-Long Wu Da Lou fu-Qi cheng La-Mei Lin National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao 266580ShandongChina PetroChina Dagang Oilfield Company Tianjin300280China

Coal is a solid combustible mineral,and coal-bearing strata have important hydrocarbon generation potential and contribute to more than 12%of the global hydrocarbon ***,the deposition and hydrocarbon evolution process of ancient coal-bearing strata is characterized by multiple geological times,leading to obvious distinctions in their hydrocarbon generation potential,geological processes,and production,which affect the evaluation and exploration of hydrocarbon resources derived from coaly source rocks *** study aimed to identify the differences on oil-generated parent macerals and the production of oil generated from different coaly source rocks and through different oil generation *** with the analysis of previous tectonic burial history and hydrocarbon generation history,high-temperature and high-pressure thermal simulation experiments,organic geochemistry,and organic petrology were performed on the Carboniferous-Permian(C-P)coaly source rocks in the Huanghua Depression,Bohai Bay *** oil-generated parent macerals of coal's secondary oil generation process(SOGP)were mainly hydrogen-rich collotelinite,collodetrinite,sporinite,and cutinite,while the oil-generated parent macerals of tertiary oil generation process(TOGP)were the remaining small amount of hydrogen-rich collotelinite,sporinite,and cutinite,as well as dispersed soluble organic matter and unexhausted residual *** with coal,the oil-generated parent macerals of coaly shale SOGP were mostly sporinite and *** part of hydrogen-poor vitrinite,lacking hydrocarbon-rich macerals,and macerals of the TOGP,in addition to some remaining cutinite and a small amount of crude oil and bitumen from SOGP contributed to the oil *** results indicated that the changes in oil yield had a good junction between SOGP and TOGP,both coal and coaly shale had higher SOGP aborted oil yield than TOGP starting yield,and coaly shale TOGP peak oil yield was low

关键词： Thermal simulation Multi-time oil generation processes Coaly source rock Carboniferous-permian Huanghua Depression

Cryptic diversity and rampant hybridization in annual gentians on the Qinghai-Tibet Plateau revealed by population genomic analysis

在线全文

学校读者我要写书评

暂无评论

Plant Diversity 2024年第2期46卷 194-205页

作者： Peng-cheng fu Qiao-Qiao Guo Di Chang Qing-Bo Gao Shan-Shan Sun School of Life Science Luoyang Normal UniversityLuoyang 471934PR China Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810001PR China

Understanding the evolutionary and ecological processes involved in population differentiation and speciation provides critical insights into biodiversity formation. In this study, we employed 29,865 single nucleotide polymorphisms(SNPs) and complete plastomes to examine genomic divergence and hybridization in Gentiana aristata, which is endemic to the Qinghai-Tibet Plateau(QTP) region. Genetic clustering revealed that G. aristata is characterized by geographic genetic structures with five clusters(West, East, Central, South and North). The West cluster has a specific morphological character(i.e., blue corolla) and higher values of FSTcompared to the remaining clusters, likely the result of the geological barrier formed by the Yangtze River. The West cluster diverged from the other clusters in the Early Pliocene;these remaining clusters diverged from one another in the Early Quaternary. Phylogenetic reconstructions based on SNPs and plastid data revealed substantial cyto-nuclear conflicts. Genetic clustering and D-statistics demonstrated rampant hybridization between the Central and North clusters,along the Bayankala Mountains, which form the geological barrier between the Central and North clusters. Species distribution modeling demonstrated the range of G. aristata expanded since the Last Interglacial period. Our findings provide genetic and morphological evidence of cryptic diversity in G. aristata, and identified rampant hybridization between genetic clusters along a geological *** findings suggest that geological barriers and climatic fluctuations have an important role in triggering diversification as well as hybridization, indicating that cryptic diversity and hybridization are essential factors in biodiversity formation within the QTP region.

关键词： Gentiana aristata Hybrid zone Qinghai-Tibet Plateau Plastome Nuclear SNPs

Molecule-based vertical transistor via intermolecular charge transport throughπ-πstacking

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第5期17卷 4573-4581页

作者： cheng Liu cheng fu Lingyu Tang Jianghua Wu Zhangyan Mu Yamei Sun Yanghang Pan Bailin Tian Kai Bao Jing Ma Qiyuan He Mengning Ding Key Laboratory of Mesoscopic Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China Jiangsu Key Laboratory of Advanced Organic Materials School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China National Laboratory of Solid State Microstructures Jiangsu Key Laboratory of Artificial Functional MaterialsCollege of Engineering and Applied SciencesCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China Department of Materials Science and Engineering City University of Hong KongHong Kong 999077China

Theπ-πstacking is a well-recognized intermolecular interaction that is responsible for the construction of electron hopping channels in numerous conducting frameworks/***,the exact role ofπ-to-πchannels within typical single crystalline organic semiconductors remains unclear as the orientations of these molecules are diverse,and their control usually requires additional side chain groups that misrepresent the intrinsic properties of the original semiconducting ***,the construction of conduction channels with intrinsicπ-πstacking in the molecule-based device is crucial for the utilization of their unique transport characteristics and understanding of the transport *** this end,we present a molecular intercalation strategy that integrates two-dimensional layered materials with functional organic semiconductor molecules for functional molecule-based *** organic semiconductor molecules can be effectively intercalated into the van der Waals gaps of semi-metallic TaS_(2) withπ-πstacking configuration and controlled intercalant *** results show that the vertical charge transport in the stacking direction shows a tunneling-dominated mechanism that strongly depends on the molecular ***,we demonstrated a new type of molecule-based vertical transistor in which TaS_(2) andπ-πstacked organic molecules function as the electrical contact and the active channel,***/off ratios as high as 447 are achieved under electrostatic modulation in ionic liquid,comparable to the current state-of-the-art molecular *** study provides an ideal platform for probing intrinsic charge transport acrossπ-πstacked conjugated molecules and also a feasible approach for the construction of high-performance molecule-based electronic devices.

关键词： π-πstacking electrochemical intercalation organic semiconductor electrical transport tunneling field effect transistor

Nanocomposite: Keggin-type Co_(4)-polyoxometalate@cobaltporphyrin linked graphdiyne for hydrogen evolution in seawater

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第3期17卷 1281-1287页

作者： Jiejie Ping Danyang He Fei Wang Nan Wang Yi-cheng fu Zihao Xing Zhiyu Jia Guo-Yu Yang Key Laboratory of Cluster Science Ministry of EducationSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081China Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education Facluty of Chmeistry Northeast Normal UniversityChangchun 130024China Peking University Third Hospital Beijing 100190China

Polyoxometalate-based nanocomposites with electrocatalytic activity have been applied in hydrogen evolution reactions(HER).Seawater as the main water resource on the earth should be developed as the water electrolysis to prepare high-purity *** this paper,we used two synthesis strategies to prepare the nanocomposite Co_(4)-POM@Co-PGDY(Co_(4)-POM:the Kegging-type microcrystals of K_(10)[Co_(4)(PW_(9)O_(3)4)2]and Co-PGDY:cobalt-porphyrin linked graphdiyne)with excellent activity for ***-PGDY as the porous material is applied not only as the protection of microcrystals towards the metal ion in seawater but also as the co-electrocatalyst of Co_(4)-***_(4)-POM@Co-PGDY exhibits excellent HER performance in seawater electrolytes with low overpotential and high stability at high ***,we have observed a key H_(3)O+intermediate emergence on the surface of nanocomposite during hydrogen evolution process in seawater by Raman synchrotron radiation-based Fourier transform infrared(SR-FTIR).The results in this paper provide an effective strategy for preparing polyoxometalate-based electrocatalysts with high-performance toward hydrogen evolution reaction.

关键词： polyoxometalate graphdiyne seawater hydrogen evolution reaction

Screening of morphology-related genes based on predatorinduced transcriptome sequencing and the functional analysis of Dagcut gene in Daphnia galeata

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2024年第4期70卷 440-452页

作者： Ya-Qin Cao Ya-Jie Zhao Hui-Ying Qi Jin-Fei Huang fu-cheng Zhu Wen-Ping Wang Dao-Gui Deng School of Life Science Huaibei Normal UniversityHuaibei 235000AnhuiChina

High fish predation pressure can trigger"induced defense"in Daphnia species,resulting in phenotypic plasticity in morphology,behavior,or life-history *** molecular mechanisms of defense morphogenesis(e.g.,the tail spine and helmet)in Daphnia remain *** the pres-ent study,the tail spine,helmet,and body of Daphnia galeata under fish and non-fish kairomones conditions were collected for transcriptome analysis.A total of 24 candidate genes related to the morphological defense of *** were identified,including 2 trypsin,one cuticle protein,1 C1qDC protein,and 2 ferritin *** function of the Dagcut gene(*** cuticle protein gene)in relation to tail spine morphology was assessed using RNA interference(RNAi).Compared with the EGFP(Enhanced green fluorescent protein)treatment,after RNAi,the expression levels of the Dagcut gene(*** cuticle protein gene)showed a significant ***,the tail spines of the offspring pro-duced by *** after RNAi of the Dagcut gene appeared curved during the *** whole-mount in situ hybridization,a clear signal site was detected on the tail spine of *** before RNAi which disappeared after *** results suggest that the Dagcut gene may play an important role in tail spine formation of ***,and will provide a theoretical basis for studying the molecular mechanisms of the morpho-logical plasticityin cladocera inthefuture.

关键词： Dagcut Daphnia galeata fish kairomones RNAi tail spine transcriptome sequencing.

基于GUM法的风电叶片结构试验方法不确定度研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

太阳能学报 2024年第5期45卷 126-132页

作者：邢海瑞傅程朱雷中国船级社质量认证有限公司北京100010

针对风电叶片全尺寸结构试验方法,首先分析试验过程中所需测量物理量的不确定度因素来源;其次利用GUM法建立不确定度数学模型,然后评定各部分输入量的标准不确定度;最后分析得到叶片结构试验各测试物理量的合成标准不确定度和扩展不确定... 详细信息

针对风电叶片全尺寸结构试验方法,首先分析试验过程中所需测量物理量的不确定度因素来源;其次利用GUM法建立不确定度数学模型,然后评定各部分输入量的标准不确定度;最后分析得到叶片结构试验各测试物理量的合成标准不确定度和扩展不确定度,从而建立风电叶片试验不确定度的系统评价方法。

关键词：风力机叶片不确定度分析全尺寸结构试验 GUM法

维普期刊数据库博看期刊

焦虑对雌性成年斑马鱼热耐受和游泳能力的影响

在线全文

学校读者我要写书评

暂无评论

水生生物学报 2024年第9期48卷 1566-1572页

作者：李小红付成付世建重庆师范大学进化生理与行为学实验室淡水鱼类资源保护与利用重庆市重点实验室重庆401331

为研究焦虑对鱼类热耐受和游泳能力的影响,以雌性成年斑马鱼(Danio rerio)为研究对象,将实验鱼随机分为焦虑组和对照组,焦虑组通过2周慢性不可预测应激(Unpredictable chronic stress, UCS)处理建立焦虑斑马鱼模型,对照组不做任何处理。... 详细信息

为研究焦虑对鱼类热耐受和游泳能力的影响,以雌性成年斑马鱼(Danio rerio)为研究对象,将实验鱼随机分为焦虑组和对照组,焦虑组通过2周慢性不可预测应激(Unpredictable chronic stress, UCS)处理建立焦虑斑马鱼模型,对照组不做任何处理。2周后测定两组实验鱼的焦虑行为相关指标、全身皮质醇及雌二醇水平,热耐受[临界高温(CT_(max))、临界低温(CT_(min))、致死高温(LT_(max))和致死低温(LT_(min))]及游泳能力(最大匀加速游泳速度, Ucat)。结果显示:焦虑组实验鱼的焦虑水平、皮质醇水平显著高于对照组(P0.05)。研究表明:2周UCS处理能建立焦虑斑马鱼模型,焦虑引起的雌性成年斑马鱼雌激素分泌减少可能对斑马鱼后期的繁殖产生消极影响;另外,焦虑降低了斑马鱼的低温耐受能力,可能与皮质醇水平升高和焦虑导致的体质下降有关。

关键词：焦虑热耐受最大匀加速游泳速度慢性不可预测应激斑马鱼

维普期刊数据库博看期刊