检索结果-南通市图书馆

Method of reverberation ray matrix for static analysis of planar framed structures composed of anisotropic Timoshenko beam members

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2015年第2期36卷 233-242页

作者： jiao ZHANG Guohua NIE School of Aerospace Engineering and Applied Mechanics Tongji University

Based on the method of reverberation ray matrix（MRRM）, a reverberation matrix for planar framed structures composed of anisotropic Timoshenko（T） beam members containing completely hinged joints is developed for static analysis of such *** the MRRM for dynamic analysis, amplitudes of arriving and departing waves for joints are chosen as unknown quantities. However, for the present case of static analysis, displacements and rotational angles at the ends of each beam member are directly considered as unknown quantities. The expressions for stiffness matrices for anisotropic beam members are developed. A corresponding reverberation matrix is derived analytically for exact and unified determination on the displacements and internal forces at both ends of each member and arbitrary cross sectional locations in the structure. Numerical examples are given and compared with the finite element method（FEM） results to validate the present model. The characteristic parameter analysis is performed to demonstrate accuracy of the present model with the T beam theory in contrast with errors in the usual model based on the Euler-Bernoulli（EB） beam theory. The resulting reverberation matrix can be used for exact calculation of anisotropic framed structures as well as for parameter analysis of geometrical and material properties of the framed structures.

关键词： planar framed structure anisotropic Timenshenko(T) beam stiffness matrix method of reverberation ray matrix(MRRM) static analysis

Mechanical properties and friction behaviors of CNT/AlSi_(10)Mg composites produced by spark plasma sintering

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2017年第5期24卷 584-593页

作者： Lin-zhi Wang Ying Liu jiao-jiao Wu Xi Zhang Chongqing Key Laboratory of Additive Manufacturing Technology and Systems Chongqing Institute of Green and Intelligent TechnologyChinese Academy of Sciences College of Material Science and Engineering Sichuan University College of Material Science and Engineering Southwest Jiaotong university

The mechanical properties and friction behaviors of CNT/AlSi10Mg composites produced by spark plasma sintering (SPS) were investigated. The results showed that the densities of the sintered composites gradually increased with increasing sintering temperature and that the highest microhardness and compressive strength were achieved in the specimen sintered at 450A degrees C. CNTs dispersed uniformly in the Al-Si10Mg matrix when the addition of CNTs was less than 1.5wt%. However, when the addition of CNTs exceeded 1.5wt%, the aggregation of CNTs was clearly observed. Moreover, the mechanical properties (including the densities, compressive strength, and microhardness) of the composites changed with CNT content and reached a maximum value when the CNT content was 1.5wt%. Meanwhile, the minimum average friction coefficient and wear rate of the CNT/AlSi10Mg composites were obtained with 1.0wt% CNTs.

关键词： metal matrix composites carbon nanotubes (CNTs) aluminum silicon magnesium alloys spark plasma sintering mechanical properties friction

Impact of slope farmland use change on ecosystem services value in China,2000-2020

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2023年第3期20卷 821-833页

作者： ZENG Jie BIAN jiao-jiao CHEN Wan-xu Department of Geography School of Geography and Information EngineeringChina University of GeosciencesWuhan430074China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China

Slope farmland is an important component of farmland resources in *** utilization and change of slope farmland have significant effects on ecosystems,and understanding the impact of slope farmland change on ecosystem services(ESs)is critical for effective land utilization and ecosystem *** study aims to analyze slope farmland changes in China between 2000 and 2020 and quantify the impact of these changes on ESs by the use of a land use dynamic attitude study,and an ecosystem services value(ESV)*** show that the area of slope farmland in China was mainly concentrated on slopes of 2°-6°,and exhibited a downward trend between 2000 and *** were significant differences in the spatial distribution of the farmland,which was mainly located in the Taihang,Qinling,Wushan,and Xuefeng *** increased by$179.235 million due to the conversion between slope farmland and forest,grassland,and construction land from ***,from 2010 to 2020,ESV decreased by$2613.919 million due to the conversion of forest and grassland to slope farmland as well as the conversion of slope farmland to construction land.

关键词： Slope farmland change Revised benefit transfermethod Ecosystemservicesvalue Ecosystem services management Slope farmland utilization China

Heat Stress Upregulates the Expression of TLR4 and Its Alternative Splicing Variant in Bama Miniature Pigs

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2014年第11期13卷 2479-2487页

作者： JU Xiang-hong XU Han-jin YONG Yan-hong AN Li-long XU Ying-mei jiao Pei-rong LIAO Ming Department of Veterinary Medicine Guangdong Ocean University Key Laboratory of Animal Disease Control and Prevention Ministry of Agriculture/College of Veterinary MedicineSouth China Agricultural University Department of Animal Science Guangdong Ocean University

Alternative splicing is a cellular mechanism in eukaryotes that results in considerable diversity ofgene products. It plays an important role in several diseases and cellular signal regulation. Heat stress is a major factor that induces immunosuppression in pigs. Little is known about the correlation between alternative splicing and heat stress in pigs. Therefore, this study aimed to clone, sequence and quantify the alternative splicing variant of toll-like receptor 4 （TLR4） in Bama miniature pigs （Sus scrofa domestica） following exposure to heat stress. The results showed that the second exon of TLR4 was spliced and 167 bp shorter in the alternative splicing variant, and the protein was putatively identified as a type of truncated membrane protein consisting of extramembrane, transmembrane and intramembrane regions lacking a signal peptide. Further, it was not a non- classical secretory protein. Five potential reference genes were screened for their potential as reliable standards to quantify the expression of TLR4 alternative spliced variants by real-time quantitative reverse-transcriptase polymerase chain reaction （qRT-PCR）. The stability of these reference genes was ranked using the genorm and NormFinder programs, and ribosomal protein L4 （RPL4） and TATA box-binding protein （TBP） were found to be the two genes showing the most stable expression in the in vitro cultured peripheral blood mononuclear ceils （PBMCs） during heat shock. The mRNA level of the TLR4 gene （both classical and spliced） in stressed pigs increased significantly （P〈0.05）. Further, the expression levels of the alternative spliced variant of TLR4 （TLR4-ASV） showed a 2-3 folds increase in heat-stressed PBMCs as compared to control pigs. The results of the present study suggested that heat shock might modulate the host immune response by regulating the expressions of TLR4 and its alternative splicing variant.

关键词： altemative splicing variant Bama miniature pig toll-like receptor 4 heat stress

Estimation of BDS pseudorange biases with high temporal resolution:feasibility,affecting factors,and necessity

在线全文

学校读者我要写书评

暂无评论

Satellite Navigation 2023年第3期4卷 14-34页

作者： Ke Su Guoqiang jiao Department of Space Information Space Engineering UniversityNo.1 Bayi RoadBeijing 101416China University of Chinese Academy of Sciences Beijing 100049China

A common practice adopted for the pseudorange bias estimation and calibration assumes that Global Navigation Satellite System satellite-dependent pseudorange biases vary gently over *** satellite pseudorange biases are routinely estimated and provided as the products with low temporal resolution,e.g.,hourly or daily,by the *** story sounds unquestionably perfect under the acquainted *** validate the inadequacy of the above hypothesis we herein present an approach to the estimate the BeiDou Navigation Satellite System(BDS)pseudorange biases with high temporal *** feasibility,affecting factors,and necessity are ***,the Geometry-Free function models are first constructed to retrieve the linear combination of the pseudorange biases;then the pseudorange Observable-specific Signal Bias(OSB)values with respect to baseline frequencies(e.g.,BDS C2I/C6I)are estimated along with the ionosphere modeling;subsequently,all multi-frequency pseudorange OSBs are determined by using the ionospheric information with constraint conditions;finally,the possible Differential Code Bias sets are attainable with the estimated pseudorange *** the observation data of four months when the estimated BDS pseudorange biases are stable,their reliability is demonstrated with the stability at the level of sub-nanosecond and the BeiDou-3 Navigation Satellite System(BDS-3)values more stable than that of BeiDou-2 Navigation Satellite System(BDS-2).The comparison between the estimated pseudorange biases and the Chinese Academy of Sciences products reveals that the accuracy of the estimated pseudorange biases is 0.2–0.4 ***,the large magnitude of the short-term pseudorange bias variation in the tens of nanoseconds for the BDS-2 and BDS-3 are found in years 2021 and 2022,which are affected by two types of the satellite flex power for the BDS-2 and BDS-3,*** stress that it’s necessary to estimate the BDS pseudorange biases w

关键词： Beidou navigation satellite system(BDS) Pseudorange observable-specific signal bias(OSB) Differential code bias(DCB) Geometry-free(GF)function model Satellite flex power

No difference in mortality among ALPPS,two-staged hepatectomy,and portal vein embolization/ligation:A systematic review by updated traditional and network meta-analyses

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2020年第5期19卷 411-419页

作者： Paschalis Gavriilidis Robert P Sutcliffe Keith J Roberts Madhava Pai Duncan Spalding Nagy Habib long R jiao Mikael H Sodergren Department of Hepatopanceaticobiliary Surgery Imperial College Healthcare NHS TrustHammersmith HospitalLondon W120HSUK Department of Hepato-Pancreato-Biliary and Liver Transplant Surgery Queen Elizabeth University Hospitals Birmingham NHS Foundation TrustBirmingham B152THUK

Background:There is an ongoing debate on the feasibility,safety,and oncological efficacy of the associating liver partition and portal vein ligation for staged hepatectomy(ALPPS)*** aim of this study was to compare ALPPS,two-staged hepatectomy(TSH),and portal vein embolization(PVE)/ligation(PVL)using updated traditional meta-analysis and network meta-analysis(NMA).Data sources:Electronic databases were used in a systematic literature *** traditional metaanalysis and NMA were performed and *** and major morbidity were selected as primary ***:Nineteen studies including 1200 patients were selected from the pool of 436 *** these patients,315(31%)and 702(69%)underwent ALPPS and portal vein occlusion(PVO),*** mortality based on updated traditional meta-analysis,subgroup analysis of the randomized controlled trials(RCTs),and both Bayesian and frequentist NMA did not demonstrate significant differences between the ALPPS cohort and the PVE,PVL,and TSH ***,analysis of RCTs did not demonstrate significant differences of major morbidity between the ALPPS and PVO *** ALPPS cohort demonstrated significantly more favorable outcomes in hypertrophy parameters,time to operation,definitive hepatectomy,and R0 margins rates compared with the PVO *** contrast,1-year disease-free survival was significantly higher in the PVO cohort compared to the ALPPS ***:This study is the first to use updated traditional meta-analysis and both Bayesian and frequentist NMA and demonstrated no significant differences in 90-day mortality between the ALPPS and other hepatic hypertrophy ***,two high quality RCTs including 147 patients demonstrated no significant differences in major morbidity between the ALPPS and PVO cohorts.

关键词： ALPPS Hepatectomy Portal vein embolization Portal vein ligation Network meta-analysis

Liver transplantation for biliary atresia: A single-center study from China's Mainland

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2015年第32期21卷 9638-9647页

作者： Qi-gen Li Ping Wan Jian-Jun Zhang Qi-Min Chen Xiao-Song Chen long-Zhi Han Qiang Xia Department of Liver Surgery Ren Ji Hospital School of Medicine Shanghai Jiao Tong University Department of Pediatric Surgery Shanghai Children’s Medical Center School of Medicine Shanghai Jiao Tong University

AIM: To summarize our single-center experience with liver transplantation(LT) for biliary atresia(BA).METHODS: From October 2006 to December 2012, 188 children with BA were analyzed retrospectively. The stage?Ⅰ?group(from October 2006 to December 2010) comprised the first 74 patients, and the stage Ⅱ group(from January 2011 to December 2012) comprised the remaining 114 patients. Finally, 123 liver transplants were performed in 122(64.9%) patients, whereas 66 patients did not undergo LT due to denial by their parents or lack of suitable liver grafts. The selection of graft types depended on the patients' clinical status and whether a suitable living donor was available. The characteristics of patients in stages?Ⅰ?and Ⅱ were described, and the surgical outcomes of LT recipients were compared between the two stages. The KaplanMeier method was used to estimate the cumulative patient and graft survival rates, and the equality of survival distributions was evaluated using the log-rank ***: The 188 children consisted of 102 boysand 86 girls. Their ages ranged from 3 to 144 mo with a median of 8 mo. One hundred and fifteen(61.2%) patients were born in rural areas. Comparing stage?Ⅰ?and stage Ⅱ patients, the proportion of patients referred by pediatricians(43.2% vs 71.1%, respectively; P < 0.001) and the proportion of patients who previously received a Kasai procedure(KP)(32.4% vs 44.7%, respectively; P = 0.092) obviously increased, and significantly more parents were willing to treat their children with LT(73% vs 86%, respectively; P = 0.027). Grafts from living donors(102/122, 83.6%) were the most commonly used graft type. Surgical complications(16/25, 64.0%) were the main reason for posttransplant mortality. Among the living donor liver transplantation recipients(n = 102), the incidence of surgical complications was significantly reduced(34.1% vs 15.5%, respectively; P = 0.029) and survival rates of patients and grafts were greatly improved(81.8% vs 89.7%, respec

关键词： Biliary atresia Liver transplantation Kasai Living

Truncated series solutions to the(2+1)-dimensional perturbed Boussinesq equation by using the approximate symmetry method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第10期27卷 123-129页

作者： Xiao-Yu jiao School of Applied Mathematics Nanjing University of Finance and EconomicsNanjing 210046China

In this paper, the（2＋1）-dimensional perturbed Boussinesq equation is transformed into a series of two-dimensional（2 D） similarity reduction equations by using the approximate symmetry method. A step-by-step procedure is used to acquire Jacobi elliptic function solutions to these similarity equations, which generate the truncated series solutions to the original perturbed Boussinesq equation. Aside from some singular area, the series solutions are convergent when the perturbation parameter is diminished.

关键词： approximate symmetry method (2+1)-dimensional perturbed Boussinesq equation series solutions convergence of series solutions

Minimum invasive associating liver partition and portal vein ligation for staged hepatectomy

在线全文

学校读者我要写书评

暂无评论

Laparoscopic, Endoscopic and Robotic Surgery 2020年第1期3卷 1-5页

作者： Michal Kawka Tamara M.H.Gall long R.jiao Hepato-pancreato-biliary Surgical Unit Department of Surgery&CancerImperial CollegeHammersmith Hospital CampusLondonW120HSUnited Kingdom

Associating liver partition and portal vein ligation for staged hepatectomy(ALPPS)has gained interest,as the potential alternative to portal vein embolisation for inducing future liver remnant hypertrophy in patients at risk of post-hepatectomy liver failure but is associated with high morbidity and *** a result,several variant ALPPS have been reported to reduce ALPPS related morbidity and *** is able to induce more extensive hypertrophy in a shorter time-period than portal vein ***-invasive surgery,which has known benefits with regards to morbidity and mortality,has also been applied to ALPPS,with promising results regarding safety and feasibility and patient *** suggests that both laparoscopic and robot-assisted ALPPS present technically feasible and safe options for ***-invasive ALPPS offers a clear benefit to patients,including reduction of fibrous adhesions,shorter length of hospital stay,and lower ***,the technical difficulty of the procedure still limits its wide application,even to experienced hepato-pancreato-biliary centres.

关键词： ALPPS Robotic hepatectomy Laparoscopic hepatectomy Staged liver resection