检索结果-南通市图书馆

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

流星进入的可变形不规则离散元分析方法

Acta Mechanica Sinica 2024年第1期40卷 305-320页

作者：李姿雯曾祥远 Kyle t.Alfriend 冯程帆温童歌 School of Automation Beijing Institute of TechnologyBeijing 100081China texas A&M University College StationTX 77840USA

流星进入地球大气层时会发生空中解体和爆炸,威胁地球局部区域乃至全球安全针对流星进入大气演化的超高速动力学仿真研究具有重要意义.为提高预报的精确性,应关注流星体内部结构和非均匀烧蚀等对演化过程和解体后碎片运动的影响。本文... 详细信息

流星进入地球大气层时会发生空中解体和爆炸,威胁地球局部区域乃至全球安全针对流星进入大气演化的超高速动力学仿真研究具有重要意义.为提高预报的精确性,应关注流星体内部结构和非均匀烧蚀等对演化过程和解体后碎片运动的影响。本文提出了一种可变形不规则离散元方法,用于仿真分析流星进入大气层时轨迹和姿态变化、烧蚀、解体和爆轰等现象。利用多面体离散元模型可模拟不同结构的异质流星;通过拉伸多面体模型顶点,仿真流星的粗糙外形和烧蚀形变;利用Jones-Wilkins-Lee状态方程计算烧蚀产生的集中爆轰产物的压力.以Chelyabinsk流星事件中发生轨迹偏离的碎片为例,数值仿真集中爆轰产物的膨胀驱动作用对碎片运动方向和轨迹演化的影响.仿真结果表明,碎片弹出轨迹特征和烧蚀剩余质量均在观测值范围内,验证了新方法的有效性.

关键词：地球大气层多面体模型离散元方法离散元模型爆轰产物全球安全空中解体驱动作用

基于极限分析上限法的地震作用下分层地基盾构隧道开挖面稳定性研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

岩土力学 2024年第4期45卷 1201-1213页

作者：张治国罗杰朱正国 PAN Y t 孙苗苗上海理工大学环境与建筑学院上海200093 石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室河北石家庄050043 新加坡国立大学土木与环境工程系新加坡119077 浙大城市学院土木工程系浙江杭州310015 浙大城市学院城市基础设施智能化浙江省工程研究中心浙江杭州310015

目前针对盾构隧道开挖面稳定性的研究还较少考虑土体分层特性和地震作用的耦合影响,因此构建了一种在分层土体中考虑地震作用的开挖面三维对数螺旋破坏模型进行研究。首先,将地震引起的动态响应通过拟静力法简化为水平和竖直两个方向上... 详细信息

目前针对盾构隧道开挖面稳定性的研究还较少考虑土体分层特性和地震作用的耦合影响,因此构建了一种在分层土体中考虑地震作用的开挖面三维对数螺旋破坏模型进行研究。首先,将地震引起的动态响应通过拟静力法简化为水平和竖直两个方向上的惯性力作用;其次,在均质土体中的三维对数螺旋破坏机制的基础上,将其改进为适用于分层土体的三维对数螺旋破坏机制;再次,根据上限定理,在虚功率方程中引入地震惯性力所做功率,得到考虑土体分层特性和地震作用条件下的盾构隧道开挖面支护力的上限解;最后,将上限理论解与三维数值模拟结果和既有模型试验结果进行对比,得到了较好的一致性。此外,针对水平地震加速度系数和地层厚度对关键物理特征进行了影响因素分析。结果表明,当比例系数ζ>0时,极限支护力随水平地震加速度系数的增大显著增大;当ζ<0时,极限支护力随水平地震加速度系数增大而增大的趋势减弱。当水平地震加速度系数kh=0时,即在无地震作用情况下,归一化极限支护力不随ζ的变化而变化;在上硬下软土层中,下部土层厚度比的增大会引起极限支护力的增大,在上软下硬土层中,下部土层厚度比的增大会引起极限支护力的减小。

关键词：盾构隧道开挖面稳定性地震作用分层土体上限定理

Critical considerations for the management of acute abdomen in transplant patients

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

World Journal of transplantation 2024年第2期14卷 8-12页

作者： Efstathios t Pavlidis Georgios Katsanos Athanasios Kofinas Georgios tsoulfas Ioannis N Galanis theodoros E Pavlidis the 2^(nd)Department of Propaedeutic Surgery Hippokration General HospitalSchool of MedicineAristotle University of ThessalonikiThessaloniki 54642Greece Department of transplantation Surgery Center for Research and Innovation in Solid Organ TransplantationAristotle University of ThessalonikiSchool of MedicineThessaloniki 54642Greece

the number of solid organ transplantations performed annually is increasing and are increasing in the following order:Kidney,liver,heart,lung,pancreas,small bowel,and uterine ***,the outcomes of transplants are impro-ving(organ survival>90%after the 1st year).therefore,there is a high probability that a general surgeon will be faced with the management of a transplant patient with acute *** problems in immunocompromised patients may not only include graft-related problems but also nongraft-related *** perioperative regulation of immunosuppression,the treatment of accompanying problems of immunosuppression,the administration of cortisol and,above all,the realization of a rapidly deteriorating situation and the accurate evaluation and interpretation of clinical manifestations are particularly important in these *** perioperative assessment and preparation includes evaluation of the patient’s cardiovascular system and determining if the patient has hypertension or suppression of the hypothalamic-pituitary-adrenal axis,or if the patient has had any coagulation mechanism abnormalities or thromboembolic *** in transplant patients is associated with the use of calci-neurin inhibitors,corticosteroids,and antiproliferation *** times,the clinical picture is atypical,resulting in delays in diagnosis and treatment and leading to increased morbidity and *** computed tomo-graphy is of utmost importance for early diagnosis and *** recipients are prone to infections,especially specific infections caused by cytomegalovirus and Clostridium difficile,and they are predisposed to intraop-erative or postoperative complications that require great care and *** is necessary to follow evidence-based therapeutic ***,it is required that the clinician choose the correct therapeutic plan for the patient(conservative,emergency open surgery or minimally invasive s

关键词： Acute abdomen Abdominal emergency surgery transplantation Immunocompromised patients Immuno-suppression Posttransplantation surgery

Endophytic Occupation in Nodules of Rhynchosia Plants from Semiarid Regions of Argentina

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2024年第6期93卷 1081-1099页

作者： Cinthia t.Lucero María de los Á.Ruíz Fabiola Pagliero Carolina Castaño Mariela L.Ambrosino Graciela S.Lorda Facultad de Ciencias Exactas y Naturales Universidad Nacional de La PampaRuta Nacional 35km 330Santa RosaLa PampaCP6300Argentina INtA EEA Anguil“Ing.Agr.Guillermo Covas”Ruta Nacional 5 km 580AnguilLa PampaCC116326Argentina

Beneﬁcial microbes can improve soil health by promoting soil structure,nutrient cycling,and disease *** addition,a wide array of rhizospheric microbes are responsible for producing metabolically active compounds including various types of plant growth ***,microbial biodiversity studies could contribute to the improvement of agricultural practices in deprived areas,such as the Pampean semiarid *** vast majority of studies conducted on endophytic microorganisms have focused on intensive crop legume *** contrast,little attention has been paid to microorganisms of native legumes,whose ecology is not directly affected by human *** this study,endophytic microorganisms isolated from root nodules of a selected native legume of the genus Rhynchosia were *** isolates were studied with a focus on their plant growth-pro-moting rhizobacteria(PGPR)*** the edaphic characteristics of the Pampean semiarid region,the isolates obtained were evaluated for their ability to grow under three salt stress conditions(50,100,and 200 mM NaCl)and four different pH values(6,7,8,and 9).Based on their PGPR activities,the selected strains were phylogenetically grouped using *** results showed great variability among the isolates in terms of the characteristics *** legumes manifested a wide endophytic variability and remarkable perfor-mance in PGPR *** conclude that they could be used as potential bioinoculants for legume cultivation,an excellent alternative to the use of chemical fertilizers that currently pollute the environment.

关键词： Native strains endophytes PGPR native legumes stress

Universal silicon ring resonator for error-free transmission links

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photonics Research 2024年第4期12卷 701-711页

作者： JUNBO ZHU WEIWEI ZHANG KE LI BHARAt PANt MARtIN EBERt XINGZHAO YAN MEHDI BANAKAR DEHN t.tRAN CALLUM G.LIttLEJOHNS FUWAN GAN GRAHAM REED DAVID J.tHOMSON Optoelectronics Research Centre University of SouthamptonSouthampton SO171BJUK National Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China University of Chinese Academy of Sciences Beijing 100049China Peng Cheng Laboratory ShenzhenChina

We report the design, fabrication, and characterization of a universal silicon PN junction ring resonator for C band error-free communication links operated up to 50 Gb/s with co-designed optical modulation and detection performance. the universal p-n junction ring device shows co-designed detection responsivity up to 0.84 A/W, in conjunction with a modulation efficiency of -4 V·mm and>8 d B optical modulation extinction ratio, enabling C band 50 Gb/s NRZ communication link with a bit error rate≤3×10^(-12).

关键词： Gb/s resonator communication

Hepatic grooves:An observational study at laparoscopic surgery

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

World Journal of Experimental Medicine 2024年第2期14卷 97-102页

作者： Shamir O Cawich Dexter A thomas Fawwaz Mohammed Michael t Gardner Marlene Craigie Shaneeta Johnson Ramnanand S Kedambady Department of Surgery University of the West IndiesSt Augustine 000000Trinidad and Tobago Department of Surgery Port of Spain General HospitalPort of Spain 000000Trinidad and Tobago Section of Anatomy Basic Medical SciencesUniversity of the West IndiesKingston 000000Jamaica Department of Radiology University of the West IndiesKingston 000000Jamaica Department of Surgery Morehouse School of MedicineAtlantaGA 30310United States Section of Anatomy Department of Basic Medical SciencesUniversity of the West IndiesKingston KIN7Jamaica

BACKGROUND In traditional descriptions,the upper surface of the liver is smooth and convex,but deep depressions are variants that are present in 5%-40%of *** sought to determine the relationship between surface depressions and the *** to use exploratory laparoscopy to determine the relationship between surface depressions and the *** An observational study was performed in all patients undergoing laparoscopic upper gastro-intestinal operations between January 1,2023 and January 20,2024.A thirty-degree laparoscope was used to inspect the liver and *** surface depressions were present,we recorded patient demographics,presence of diaphragmatic bands,rib protrusions and/or any other source of compression during *** Of 394 patients,343 had normal surface anatomy,and 51(12.9%)had prominent surface depressions on the *** was no significant relationship between the presence of surface depressions and gender nor the presence of rib ***,there was significant association between the presence of surface depressions and diaphragmatic muscular bands(Pth these data,the diaphragmatic-band theory has gained increased importance over other theories for surface *** studies are warranted using cross sectional imaging to confirm relationships with intersectional planes as well as beta-catenin assays in the affected liver parenchyma.

关键词： Liver Variant Vein Hepatic Surgery

Impact of sleep on gastrointestinal cancer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Oncology 2024年第6期15卷 677-683页

作者： Joshua Lo Pahnwat t taweesedt Makoto Kawai Department of Internal Medicine Santa Clara Valley Medical CenterSan JoseCA 95128United States Department of Psychiatry and Behavioral Sciences Stanford UniversityStanfordCA 94305United States Sierra Pacific Mental Illness Research Educationand Clinical Center(MIRECC)VA Palo Alto Health Care SystemPalo AltoCA 94304United States Department of Psychiatry and Behavioral Sciences School of MedicineStanford UniversityRedwood CityCA 94063United States

Sleep problems have become a significant public health concern,affecting a large portion of the global population and have been linked to increased morbidity and *** incidence of gastrointestinal(GI)cancers continues to rise,posing a substantial burden on healthcare systems *** editorial aims to delve into the impact of sleep on GI cancers,including esophageal,gastric,colorectal,hepatobiliary,and pancreatic *** literature investigating the potential connections between GI cancers and sleep was *** considered aspects such as sleep duration,sleep disorders,and circadian rhythmicity,in order to explore the underlying mechanisms that can contribute to the development of GI cancers and propose avenues for future research.

关键词： Sleep Cancer Gastrointestinal cancer Esophagus Stomach Colon Liver

High association strengths are linked to phenotypic similarity,including plumage color and patterns,of participants in mixed-species bird flocks of southwestern China

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1期70卷 34-44页

作者： Liping Zhou Christos Mammides Youfang Chen Wenyi Zhou Wenzhang Dai Edward L.Braun Rebecca t.Kimball Yang Liu Scott K.Robinson Eben Goodale Guangxi Key Laboratory of Forest Ecology and Conservation College of ForestryGuangxi UniversityNanning 530004China Kunming Natural History Museum of Zoology Kunming Institute of ZoologyChinese Academy of SciencesKunming 650223China Nature Conservation Unit Frederick University7Yianni Frederickou StreetPallouriotissaNicosia 1036Cyprus State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China Florida Museum of Natural History University of FloridaGainesvilleFL 34201USA Department of Biology University of FloridaGainesvilleFL 34201USA School of Life Science and Institute of Wetland Ecology Nanjing UniversityNanjing 210000China State Key Laboratory of Biocontrol School of EcologySun-Yatsen UniversityGuangzhou 510275China Department of Health and Environmental Science Xi'an Jiaotong Liverpool UniversitySuzhou 215123China

Participants in mixed-species bird flocks(MSFs)have been shown to associate with species that are similar in body size,diet,and evolutionary history,suggesting that facilitation structures these *** addition,several studies have suggested that species in MsFs resemble each other in their plumage,but this question has not been systematically investigated for any MsF *** the nonbreeding season of 2020 and 2021,we sampled 585 MSFs on 14 transects in 2 habitats of tongbiguang Nature Reserve in western Yunnan Province,*** performed social network analysis and the Multiple Regression Quadratic Assignment Procedure to evaluate the effect of 4 species traits(body size,overall plumage color,distinctive plumage patterns,and diet)and evolutionary history on species association strength at the whole-MSF and within-MSF *** 41 significant relationships showed that species with stronger associations were more similar in their various *** size had the strongest effect on association strength,followed by phylogeny,plumage patterns,and plumage color;diet had the weakest *** results are consistent with the hypotheses that the benefits of associating with phenotypically similar species outweigh the potential costs of interspecific competition,and that trait matching can occur in plumage characteristics,albeit more weakly than in other *** explanations exist as to why similarities in plumage may occur in MSFs,including that they could reduce predators'ability to target phenotypically"odd"*** trait matching in plumage occurs through assortative processes in ecological time or is influenced by co-evolution requires furtherstudy.

关键词： co-evolution interaction networks mixed-species animal groups phenotypic similarity trait convergence

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

悠长午觉

中学生英语 2024年第17期 11-13页

作者： Elizabeth t. 李明娟

埃拉从不喜欢午睡。当她还是个婴儿时,她会整个下午呆在卧室外面玩玩具。她的母亲告诉她,无论她房间的窗帘有多暗多厚,埃拉都只在外面天黑的时候才会睡觉。在埃拉小学二年级的时候,她已经不记得上次午睡是什么时候了。埃拉晚上睡得很好...

埃拉从不喜欢午睡。当她还是个婴儿时,她会整个下午呆在卧室外面玩玩具。她的母亲告诉她,无论她房间的窗帘有多暗多厚,埃拉都只在外面天黑的时候才会睡觉。在埃拉小学二年级的时候,她已经不记得上次午睡是什么时候了。埃拉晚上睡得很好,但她认为午睡是婴儿和病人才会做的事。但即使埃拉生病了,她也不睡午觉,而是躺在床上看书。

关键词：