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Elucidating regulatory processes of intense physical activity by multi-omics analysis
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作者 Ernesto S.Nakayasu Marina A.Gritsenko +17 位作者 Young-Mo Kim Jennifer E.Kyle Kelly G.Stratton Carrie D.Nicora Nathalie Munoz Kathleen M.Navarro Daniel Claborne Yuqian Gao Karl K.Weitz Vanessa L.Paurus Kent J.Bloodsworth Kelsey A.Allen Lisa M.Bramer Fernando Montes Kathleen A.Clark Grant Tietje Justin Teeguarden Kristin E.Burnum-Johnson 《Military Medical Research》 SCIE CAS CSCD 2024年第4期479-499,共21页
Background:Physiological and biochemical processes across tissues of the body are regulated in response to the high demands of intense physical activity in several occupations,such as firefighting,law enforcement,mili... Background:Physiological and biochemical processes across tissues of the body are regulated in response to the high demands of intense physical activity in several occupations,such as firefighting,law enforcement,military,and sports.A better understanding of such processes can ultimately help improve human performance and prevent illnesses in the work environment.Methods:To study regulatory processes in intense physical activity simulating real-life conditions,we performed a multi-omics analysis of 3 biofluids(blood plasma,urine,and saliva)collected from 11 wildland firefighters before and after a 45 min,intense exercise regimen.Omics profiles post-vs.pre-exercise were compared by Student’s t-test followed by pathway analysis and comparison between the different omics modalities.Results:Our multi-omics analysis identified and quantified 3835 proteins,730 lipids and 182 metabolites combining the 3 different types of samples.The blood plasma analysis revealed signatures of tissue damage and acute repair response accompanied by enhanced carbon metabolism to meet energy demands.The urine analysis showed a strong,concomitant regulation of 6 out of 8 identified proteins from the renin-angiotensin system supporting increased excretion of catabolites,reabsorption of nutrients and maintenance of fluid balance.In saliva,we observed a decrease in 3 pro-inflammatory cytokines and an increase in 8 antimicrobial peptides.A systematic literature review identified 6 papers that support an altered susceptibility to respiratory infection.Conclusions:This study shows simultaneous regulatory signatures in biofluids indicative of homeostatic maintenance during intense physical activity with possible effects on increased infection susceptibility,suggesting that caution against respiratory diseases could benefit workers on highly physical demanding jobs. 展开更多
关键词 multi-omics analysis Intense exercise Human performance BIOFLUIDS Metabolism Immunity
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Bunch-length measurement at a bunch-by-bunch rate based on time–frequency-domain joint analysis techniques and its application
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作者 Hong-Shuang Wang Xing Yang +2 位作者 Yong-Bin Leng Yi-Mei Zhou Ji-Gang Wang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第4期165-175,共11页
This paper presents a new technique for measuring the bunch length of a high-energy electron beam at a bunch-by-bunch rate in storage rings.This technique uses the time–frequency-domain joint analysis of the bunch si... This paper presents a new technique for measuring the bunch length of a high-energy electron beam at a bunch-by-bunch rate in storage rings.This technique uses the time–frequency-domain joint analysis of the bunch signal to obtain bunch-by-bunch and turn-by-turn longitudinal parameters,such as bunch length and synchronous phase.The bunch signal is obtained using a button electrode with a bandwidth of several gigahertz.The data acquisition device was a high-speed digital oscilloscope with a sampling rate of more than 10 GS/s,and the single-shot sampling data buffer covered thousands of turns.The bunch-length and synchronous phase information were extracted via offline calculations using Python scripts.The calibration coefficient of the system was determined using a commercial streak camera.Moreover,this technique was tested on two different storage rings and successfully captured various longitudinal transient processes during the harmonic cavity debugging process at the Shanghai Synchrotron Radiation Facility(SSRF),and longitudinal instabilities were observed during the single-bunch accumulation process at Hefei Light Source(HLS).For Gaussian-distribution bunches,the uncertainty of the bunch phase obtained using this technique was better than 0.2 ps,and the bunch-length uncertainty was better than 1 ps.The dynamic range exceeded 10 ms.This technology is a powerful and versatile beam diagnostic tool that can be conveniently deployed in high-energy electron storage rings. 展开更多
关键词 Bunch-by-bunch diagnostic Bunch-length measurement Synchronous phase measurement joint time–frequency-domain analysis Longitudinal instability
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Finite Element Analysis of Tubular KK Joint under Compressive Loading
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作者 Mohammad Tanzil Hasan Md. Jobayer Mia Md. Syful Isalm Bipul 《American Journal of Computational Mathematics》 2024年第3期291-304,共14页
KK tubular joints are used to build jacket-type offshore structures. These joints are mostly made up of structural steel. These joints can withstand yield, buckling, and lateral loads depending on the structure’s des... KK tubular joints are used to build jacket-type offshore structures. These joints are mostly made up of structural steel. These joints can withstand yield, buckling, and lateral loads depending on the structure’s design and environment. In this study, the Finite Element Model of the KK-type tubular joint has been created, and analysis has been performed under static loading using the Static Structural analysis system of ANSYS 19.2 commercial software and structural mechanics module of COMSOL Multiphysics. The KK tubular model is analyzed under compressive load conditions, and the resulting stress, strain, and deformation values are tabulated in both graphical and tabular form. This study includes a comparison of the outcomes from both commercial software. The results highlight that maximum stress, strain, and deformation values decrease as joint thickness increases. This study holds significant relevance in advancing the understanding of tubular KK joints and their response to compressive loading. The insights derived from the analysis have the potential to contribute to the development of more robust and reliable tubular KK joints in various engineering and structural applications. . 展开更多
关键词 KK joint BRACE Offshore Structures CHORD Numerical analysis Static analysis
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Action of circulating and infiltrating B cells in the immune microenvironment of colorectal cancer by single-cell sequencing analysis
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作者 Jing-Po Zhang Bing-Zheng Yan +1 位作者 Jie Liu Wei Wang 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第6期2683-2696,共14页
BACKGROUND The complexity of the immune microenvironment has an impact on the treatment of colorectal cancer(CRC),one of the most prevalent malignancies worldwide.In this study,multi-omics and single-cell sequencing t... BACKGROUND The complexity of the immune microenvironment has an impact on the treatment of colorectal cancer(CRC),one of the most prevalent malignancies worldwide.In this study,multi-omics and single-cell sequencing techniques were used to investigate the mechanism of action of circulating and infiltrating B cells in CRC.By revealing the heterogeneity and functional differences of B cells in cancer immunity,we aim to deepen our understanding of immune regulation and provide a scientific basis for the development of more effective cancer treatment strategies.AIM To explore the role of circulating and infiltrating B cell subsets in the immune microenvironment of CRC,explore the potential driving mechanism of B cell development,analyze the interaction between B cells and other immune cells in the immune microenvironment and the functions of communication molecules,and search for possible regulatory pathways to promote the anti-tumor effects of B cells.METHODS A total of 69 paracancer(normal),tumor and peripheral blood samples were collected from 23 patients with CRC from The Cancer Genome Atlas database(https://portal.gdc.cancer.gov/).After the immune cells were sorted by multicolor flow cytometry,the single cell transcriptome and B cell receptor group library were sequenced using the 10X Genomics platform,and the data were analyzed using bioinformatics tools such as Seurat.The differences in the number and function of B cell infiltration between tumor and normal tissue,the interaction between B cell subsets and T cells and myeloid cell subsets,and the transcription factor regulatory network of B cell subsets were explored and analyzed.RESULTS Compared with normal tissue,the infiltrating number of CD20+B cell subsets in tumor tissue increased significantly.Among them,germinal center B cells(GCB)played the most prominent role,with positive clone expansion and heavy chain mutation level increasing,and the trend of differentiation into memory B cells increased.However,the number of plasma cells in the tumor microenvironment decreased significantly,and the plasma cells secreting IgA antibodies decreased most obviously.In addition,compared with the immune microenvironment of normal tissues,GCB cells in tumor tissues became more closely connected with other immune cells such as T cells,and communication molecules that positively regulate immune function were significantly enriched.CONCLUSION The role of GCB in CRC tumor microenvironment is greatly enhanced,and its affinity to tumor antigen is enhanced by its significantly increased heavy chain mutation level.Meanwhile,GCB has enhanced its association with immune cells in the microenvironment,which plays a positive anti-tumor effect. 展开更多
关键词 Colorectal cancer multi-omics analysis Single-cell sequencing analysis Immune microenvironment Infiltrating B cells
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The Immediate Analgesic Effect and Impact on Gait Function of Transcutaneous Electrical Nerve Stimulation in Late-Stage Elderly Individuals with Knee Pain: Examination of Gait Function Using an IoT-Based Gait Analysis Device
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作者 Taisuke Ito 《Open Journal of Therapy and Rehabilitation》 2024年第2期185-195,共11页
Purpose: This study verified the effects of transcutaneous electrical nerve stimulation (TENS), which can be worn during walking and exercise, in elderly individuals with late-stage knee pain who exercise regularly. M... Purpose: This study verified the effects of transcutaneous electrical nerve stimulation (TENS), which can be worn during walking and exercise, in elderly individuals with late-stage knee pain who exercise regularly. Methods: Thirty-two late-stage elderly individuals were evaluated for knee pain during rest, walking, and program exercises, with and without TENS. Gait analysis was performed using an IoT-based gait analysis device to examine the effects of TENS-induced analgesia on gait. Results: TENS significantly reduced knee pain during rest, walking, and programmed exercises, with the greatest analgesic effect observed during walking. The greater the knee pain without TENS, the more significant the analgesic effect of TENS. A comparison of gait parameters revealed a significant difference only in the gait cycle time, with a trend towards faster walking with TENS;however, the effect was limited. Conclusion: TENS effectively relieves knee pain in late-stage elderly individuals and can be safely applied during exercise. Pain management using TENS provides important insights into the implementation of exercise therapy in this age group. 展开更多
关键词 Late-Stage Elderly Knee joint Pain Exercise Transcutaneous Electrical Stimulation IoT-Based Gait analysis Device
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Static and Dynamic Mechanics Analysis on Artificial Hip Joints with Different Interface Designs by the Finite Element Method 被引量:8
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作者 Hai-bo Jiang 《Journal of Bionic Engineering》 SCIE EI CSCD 2007年第2期123-131,共9页
Four different structural models of artificial joints were developed and the finite element method (FEM) was employed to investigate their mechanical characteristics under static and dynamic conditions. The material... Four different structural models of artificial joints were developed and the finite element method (FEM) was employed to investigate their mechanical characteristics under static and dynamic conditions. The materials used in the FEM calculation were ultra-high molecular weight polyethylene (UHMWPE), 316L stainless steel, CoCrMo alloy and Ti6A14V alloy. The stress distribution, strain, and elastic deformation under static and dynamic conditions were obtained. Analysis and comparison of the ~alculation results of different models were conducted. It is shown that with the same parameters the model of a metallic femur head covered with an artificial cartilage layer is more similar to the structure of the natural human joint and its mechanical characteristics are the best of the four models. 展开更多
关键词 finite element analysis STRESS articular joint
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Effects of Joint Controller on Analytical Modal Analysis of Rotational Flexible Manipulator 被引量:7
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作者 CHU Ming ZHANG Yanheng +1 位作者 CHEN Gang SUN Hanxu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第3期460-469,共10页
Modal analysis is a fundamental and important task for modeling and control of the flexible manipulator. However, almost all of the traditional modal analysis methods view the flexible manipulator as a pure mechanical... Modal analysis is a fundamental and important task for modeling and control of the flexible manipulator. However, almost all of the traditional modal analysis methods view the flexible manipulator as a pure mechanical structure and neglect feedback action of joint controller. In order to study the effects of joint controller on the modal analysis of rotational flexible manipulator, a closed-loop analytical modal analysis method is proposed. Firstly, two exact boundary constraints, namely servo feedback constraint and bending moment constraint, are derived to solve the vibration partial differential equation. It is found that the stiffness and damping gains of joint controller are both included in the boundary conditions, which lead to an unconventional secular term. Secondly, analytical algorithm based on Ritz approach is developed by using Laplace transform and complex modal approach to obtain the natural frequencies and mode shapes. And then, the numerical simulations are performed and the computational results show that joint controller has pronounced influence on the modal parameters: joint controller stiffness reduces the natural frequency, while joint controller damping makes the shape phase non-zero. Furthermore, the validity of the presented conclusion is confirmed through experimental studies. These findings are expected to improve the performance of dynamics simulation systems and model-based controllers. 展开更多
关键词 flexible manipulator analytical modal analysis boundary constraints joint controller
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Pushover analysis of reinforced concrete frames considering shear failure at beam-column joints 被引量:4
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作者 Y.C.Sung T.K.Lin +1 位作者 C.C.Hsiao M.C.Lai 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2013年第3期373-383,共11页
Since most current seismic capacity evaluations of reinforced concrete (RC) frame structures are implemented by either static pushover analysis (PA) or dynamic time history analysis, with diverse settings of the p... Since most current seismic capacity evaluations of reinforced concrete (RC) frame structures are implemented by either static pushover analysis (PA) or dynamic time history analysis, with diverse settings of the plastic hinges (PHs) on such main structural components as columns, beams and walls, the complex behavior of shear failure at beam-column joints (BCJs) during major earthquakes is commonly neglected. This study proposes new nonlinear PA procedures that consider shear failure at BCJs and seek to assess the actual damage to RC structures. Based on the specifications of FEMA-356, a simplified joint model composed of two nonlinear cross struts placed diagonally over the location of the plastic hinge is established, allowing a sophisticated PA to be performed. To verify the validity of this method, the analytical results for the capacity curves and the failure mechanism derived from three different full-size RC frames are compared with the experimental measurements. By considering shear failure at BCJs, the proposed nonlinear analytical procedures can be used to estimate the structural behavior of RC frames, including seismic capacity and the progressive failure sequence of joints, in a precise and effective manner. 展开更多
关键词 RC frame beam-column joint pushover analysis capacity curve plastic hinge performance-based seismic evaluation
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Joint Analysis Method for Major Genes Controlling Multiple Correlated Quantitative Traits 被引量:5
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作者 XIAO Jing WANG Xue-feng HU Zhi-qiu TANG Zai-xiang SUI Jiong-ming LI Xin XU Chen-wu 《Agricultural Sciences in China》 CAS CSCD 2006年第3期179-187,共9页
Based on the major gene and polygene mixed inheritance model for multiple correlated quantitative traits, the authors proposed a new joint segregation analysis method of major gene controlling multiple correlated quan... Based on the major gene and polygene mixed inheritance model for multiple correlated quantitative traits, the authors proposed a new joint segregation analysis method of major gene controlling multiple correlated quantitative traits, which include major gene detection and its effect and variation estimation. The effect and variation of major gene are estimated by the maximum likelihood method implemented via expectation-maximization (EM) algorithm. Major gene is tested with the likelihood ratio (LR) test statistic. Extensive simulation studies showed that joint analysis not only increases the statistical power of major gene detection but also improves the precision and accuracy of major gene effect estimates. An example of the plant height and the number of tiller of F2 population in rice cross Duonieai x Zhonghua 11 was used in the illustration. The results indicated that the genetic difference of these two traits in this cross refers to only one pleiotropic major gene. The additive effect and dominance effect of the major gene are estimated as -21.3 and 40.6 cm on plant height, and 22.7 and -25.3 on number of tiller, respectively. The major gene shows overdominance for plant height and close to complete dominance for number of tillers. 展开更多
关键词 multiple correlated quantitative traits major gene joint segregation analysis maximum likelihood estimation EM algorithm
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Sacroiliac joint stability: Finite element analysis of implant number, orientation, and superior implant length 被引量:3
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作者 Derek P Lindsey Ali Kiapour +1 位作者 Scott A Yerby Vijay K Goel 《World Journal of Orthopedics》 2018年第3期14-23,共10页
AIM To analyze how various implants placement variables affect sacroiliac(SI) joint range of motion. METHODS An experimentally validated finite element model of the lumbar spine and pelvis was used to simulate a fusio... AIM To analyze how various implants placement variables affect sacroiliac(SI) joint range of motion. METHODS An experimentally validated finite element model of the lumbar spine and pelvis was used to simulate a fusion of the SI joint using various placement configurations of triangular implants(iF use Implant System~?). Placement configurations were varied by changing implant orientation, superior implant length, and number of implants. The range of motion of the SI joint was calculated using a constant moment of 10 N-m with a follower load of 400 N. The changes in motion were compared between the treatment groups to assess how the different variables affected the overall motion of the SI joint. RESULTS Transarticular placement of 3 implants with superior implants that end in the middle of the sacrum resulted in the greatest reduction in range of motion(flexion/extension = 73%, lateral bending = 42%, axial rotation = 72%). The range of motions of the SI joints were reduced with use of transarticular orientation(9%-18%) when compared with an inline orientation. The use of a superior implant that ended mid-sacrum resulted in median reductions of(8%-14%) when compared with a superior implant that ended in the middle of the ala. Reducing the number of implants, resulted in increased SI joint range of motions for the 1 and 2 implant models of 29%-133% and 2%-39%, respectively,when compared with the 3 implant model.CONCLUSION Using a validated finite element model we demonstrated that placement of 3 implants across the SI joint using a transarticular orientation with superior implant reaching the sacral midline resulted in the most stable construct. Additional clinical studies may be required to confirm these results. 展开更多
关键词 Fusion Biomechanics MINIMALLY INVASIVE surgery SACROILIAC joint DYSFUNCTION Finite element analysis
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Finite Element Modeling and Modal Analysis of Complicated Structure with Bolted Joints 被引量:3
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作者 蒲大宇 廖日东 +1 位作者 左正兴 冯慧华 《Journal of Beijing Institute of Technology》 EI CAS 2009年第3期273-277,共5页
A contact bolt model is proposed as a new modeling technique to investigate the complex structure with bolted joints for modal analysis and compared with the coupled bolt model, and the test results are given. Among t... A contact bolt model is proposed as a new modeling technique to investigate the complex structure with bolted joints for modal analysis and compared with the coupled bolt model, and the test results are given. Among these models, the coupled bolt model provides the best accurate responses compared with the experimental results. The contact bolt model shows the best effectiveness and usefulness in view of operational time. The bolt models proposed in this study are adopted for a dynamic characteristic analysis of a large diesel engine consisting of several parts which are connected by many bolts. The dynamic behavior of the entire engine structure was investigated by experiment. The coupled bolt model and the contact bolt model were applied to model the assembly of engine with high preload. The experimental results are in good agreement with the finite element method (FEM) results. Compared with the other models, the contact bolt model presented in this paper is more effective and useful in view of operational time and experience of analysts. 展开更多
关键词 finite element method(FEM) bolted joints modal analysis internal combustion engine
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Incremental dynamic analysis of concrete gravity dams including base and lift joints 被引量:2
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作者 Mohammad Alembagheri Mohsen Ghaemian 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2013年第1期119-134,共16页
The growth in computer processing power has made it possible to use time-consuming analysis methods such as incremental dynamic analysis(IDA) with higher accuracy in less time.In an IDA study,a series of earthquake ... The growth in computer processing power has made it possible to use time-consuming analysis methods such as incremental dynamic analysis(IDA) with higher accuracy in less time.In an IDA study,a series of earthquake records are applied to a structure at successively increasing intensity levels,which causes the structure to shift from the elastic state into the inelastic state and finally into collapse.In this way,the limit-states and capacity of a structure can be determined.In the present research,the IDA of a concrete gravity dam considering a nonlinear concrete behavior,and sliding planes within the dam body and at the dam-foundation interface,is performed.The influence of the friction angle and lift joint slope on the response parameters are investigated and the various limit-states of the dam are recognized.It is observed that by introducing a lift joint,the tensile damage can be avoided for the dam structure.The lift joint sliding is essentially independent of the base joint friction angle and the upper ligament over the inclined lift joint slides into the upstream direction in strong earthquakes. 展开更多
关键词 concrete gravity dams incremental dynamic analysis seismic analysis damage index dam failures jointS performance characteristics structural capacity
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Mineralization-related geochemical anomalies derived from stream sediment geochemical data using multifractal analysis in Pangxidong area of Qinzhou-Hangzhou tectonic joint belt, Guangdong Province, China 被引量:5
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作者 张焱 周永章 +8 位作者 王林峰 王正海 何俊国 安燕飞 李红中 曾长育 梁锦 吕文超 高乐 《Journal of Central South University》 SCIE EI CAS 2013年第1期184-192,共9页
Distinguishing geochemical anomalies from background is a basic task in exploratory geochemistry. The derivation of geochemical anomalies from stream sediment geochemical data and the decomposition of these anomalies ... Distinguishing geochemical anomalies from background is a basic task in exploratory geochemistry. The derivation of geochemical anomalies from stream sediment geochemical data and the decomposition of these anomalies into their component patterns were described. A set of stream sediment geochemical data was obtained for 1 880 km 2 of the Pangxidong area, which is in the southern part of the recently recognized Qinzhou-Hangzhou joint tectonic belt. This belt crosses southern China and tends to the northwest (NE) direction. The total number of collected samples was 7 236, and the concentrations of Ag, Au, Cu, As, Pb and Zn were measured for each sample. The spatial combination distribution law of geochemical elements and principal component analysis (PCA) were used to construct combination models for the identification of combinations of geochemical anomalies. Spectrum-area (S-A) fractal modeling was used to strengthen weak anomalies and separate them from the background. Composite anomaly modeling was combined with fractal filtering techniques to process and analyze the geochemical data. The raster maps of Au, Ag, Cu, As, Pb and Zn were obtained by the multifractal inverse distance weighted (MIDW) method. PCA was used to combine the Au, Ag, Cu, As, Pb, and Zn concentration values. The S-A fractal method was used to decompose the first component pattern achieved by the PCA. The results show that combination anomalies from a combination of variables coincide with the known mineralization of the study area. Although the combination anomalies cannot reflect local anomalies closely enough, high-anomaly areas indicate good sites for further exploration for unknown deposits. On this basis, anomaly and background separation from combination anomalies using fractal filtering techniques can provide guidance for later work. 展开更多
关键词 geochemical anomalies fractal modeling principal component analysis Qinzhou-Hangzhou joint tectonic belt streamsediments
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Design and Analysis of Tapered Stress Joint for Top Tensioned Riser System 被引量:2
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作者 张日曦 张崎 黄一 《China Ocean Engineering》 SCIE EI 2012年第3期507-520,共14页
Stress Joint (SJ) plays a key role in the Top Tensioned Riser (TTR) system for deep water engineering. A preliminary design method of tapered SJ is proposed in the paper, which could help designers obtain accurate... Stress Joint (SJ) plays a key role in the Top Tensioned Riser (TTR) system for deep water engineering. A preliminary design method of tapered SJ is proposed in the paper, which could help designers obtain accurate design data. After a further sensitive analysis is carried out, the related parameters choice and control methods are recommended in the engineering practice. By taking the extreme environment conditions into consideration, the effects of bending stress reduction and curve control are analyzed, and the 3-D FE models are established by ABQOUS for numerical evaluation to verify the correctness of design results. At last, dynamic analysis and fatigue analysis, based on actual project, are carried out with designed stress joint. The analysis results prove the feasibility and guidance of this method in the practical engineering applications. 展开更多
关键词 stress joint (S J) top tensioned riser (TTR) design method parameters sensitivities dynamic analysis fatigue analysis
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Elasto-plastic Analysis of Circular Tunnels in Jointed Rock Masses Satisfy the Hoek-Brown Failure Criterion 被引量:11
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作者 SUN Jin-shan LU Wen-bo ZHU Qi-hu CHEN Ming 《Journal of China University of Mining and Technology》 EI 2007年第3期393-398,共6页
The relationship between the Hoek-Brown parameters and the mechanical response of circular tunnels is il-lustrated. Closed-form and approximate solutions are given for the extent of the plastic zone and the stress and... The relationship between the Hoek-Brown parameters and the mechanical response of circular tunnels is il-lustrated. Closed-form and approximate solutions are given for the extent of the plastic zone and the stress and dis-placement fields under axisymmetrical and asymmetric stress conditions. For the same rock masses and under axisym-metrical stress conditions,the radius of the plastic zone in terms of Hoek-Brown criterion is generally an approximation of the radius in terms of the Mohr-Coulomb criterion. The radius in terms of the Hoek-Brown criterion is larger under low stress conditions. For poor quality rock masses (GSI<25),measures (such as grouting,setting rock bolts,etc.) that improve the GSI of rock masses are effective in improving the stability of tunnels. It is not advisable to improve the sta-bility of the tunnels by providing a small support resistance p through shotcrete,except for very poor quality jointed rock masses. Without reference to the quality of the rock mass,the disturbance factor D should not less than 0.5. Meas-ures which disturb rock masses during tunnel construction should be taken carefully when the tunnel depth increases. 展开更多
关键词 jointed rock masses circular tunnel general Hoek-Brown failure criterion elasto-plastic analysis con-struction measures
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Dynamic Analysis of Four-Bar Beating-up Mechanism with Joint Clearance 被引量:3
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作者 薛文良 陈国珍 +2 位作者 陈革 祝章琛 程隆棣 《Journal of Donghua University(English Edition)》 EI CAS 2010年第4期559-565,共7页
For the four-bar beating-up mechanism of air-jet loom,the plain bearing of linkage is the bearing with dynamic load,and is immersed in the lubricant-box.If the joint clearance is considered,the research on linkage mov... For the four-bar beating-up mechanism of air-jet loom,the plain bearing of linkage is the bearing with dynamic load,and is immersed in the lubricant-box.If the joint clearance is considered,the research on linkage movement could be very complicated.In this paper,the kinematic characteristics of four-bar beating-up mechanism with joint clearance were studied by analyzing the trace of journal center and the balance of radial,tangential forces,and bearing load.The region of principal vibration and its forming causes were discussed.And the results could interpret the measuring curves of four-bar beating-up mechanism completely. 展开更多
关键词 dynamic analysis four-bar linkage beating-up mechanism joint clearance
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Constraint and Mobility Change Analysis of Rubik’s Cube-inspired Reconfigurable Joints and Corresponding Parallel Mechanisms 被引量:2
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作者 Duanling Li Pu Jia +2 位作者 Jiazhou Li Dan Zhang Xianwen Kong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2020年第5期51-61,共11页
The current research of reconfigurable parallel mechanism mainly focuses on the construction of reconfigurable joints.Compared with the method of changing the mobility by physical locking joints,the geometric constrai... The current research of reconfigurable parallel mechanism mainly focuses on the construction of reconfigurable joints.Compared with the method of changing the mobility by physical locking joints,the geometric constraint has good controllability,and the constructed parallel mechanism has more configurations and wider application range.This paper presents a reconfigurable axis(rA)joint inspired and evolved from Rubik’s Cubes,which have a unique feature of geometric and physical constraint of axes of joint.The effectiveness of the rA joint in the construction of the limb is analyzed,resulting in a change in mobility and topology of the parallel mechanism.The rA joint makes the angle among the three axes inside the groove changed arbitrarily.This change in mobility is completed by the case illustrated by a 3(rA)P(rA)reconfigurable parallel mechanism having variable mobility from 1 to 6 and having various special configurations including pure translations,pure rotations.The underlying principle of the metamorphosis of this rA joint is shown by investigating the dependence of the corresponding screw system comprising of line vectors,leading to evolution of the rA joint from two types of spherical joints to three types of variable Hooke joints and one revolute joint.The reconfigurable parallel mechanism alters its topology by rotating or locking the axis of rA joint to turn all limbs into different phases.The prototype of reconfigurable parallel mechanism is manufactured and all configurations are enumerated to verify the validity of the theoretical method by physical experiments. 展开更多
关键词 Reciprocal screws Reconfigurable-axis(rA)joint Metamorphic parallel mechanism Constraint analysis
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Moiré method analysis for tensile strain field of 2024 aluminum alloy welded joint 被引量:1
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作者 徐文立 魏艳红 +3 位作者 刘雪松 方洪渊 赵敏 田锡唐 《China Welding》 EI CAS 2003年第1期39-44,共6页
Using experimental mechanics method of moiré analysis, strain field distributions of 2024 aluminum alloy welded joints under different conditions were investigated. The results show that moiré stripes of wel... Using experimental mechanics method of moiré analysis, strain field distributions of 2024 aluminum alloy welded joints under different conditions were investigated. The results show that moiré stripes of welded joint without trailing peening just before fracture are not only few and scattered but also uneven, and the stress mainly concentrates on the poor position welded toes during the tensioning process with the relatively poor mechanical properties of welded joints; When the method of welding with trailing peening is adopted, moiré stripes of welded joint just before fracture are relatively thick and even due to the strengthening welded toes during the welding process, and fracture position transfers from the welded toes to weld, at the same time the mechanical properties of welded joints are improved greatly than conventional welding which can show that the technology of trailing peening is effective to strengthen welded joints of aluminum alloy with high strength. 展开更多
关键词 tensile stress welding with trailing peening moiré analysis joint strengthening
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Dynamic Modeling and Analysis of 4UPS-UPU Spatial Parallel Mechanism with Spherical Clearance Joint 被引量:2
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作者 Xiulong Chen Mengqiang Cui 《Journal of Harbin Institute of Technology(New Series)》 CAS 2021年第3期61-78,共18页
Clearance between the moving joints is unavoidable in real working process. At present, many researches are mainly focused on dynamics of plane revolute joint in plane mechanism, but few on dynamics of spatial spheric... Clearance between the moving joints is unavoidable in real working process. At present, many researches are mainly focused on dynamics of plane revolute joint in plane mechanism, but few on dynamics of spatial spherical joint clearance in spatial parallel mechanism. In this paper, a general method is proposed for establishing dynamic equations of spatial parallel mechanism with spatial spherical clearance by Lagrange multiplier method. The kinematic model and contact force model of the spherical joint clearance were established successively. Lagrange multiplier method was used to deduce the dynamics equation of 4 UPS-UPU mechanism with spherical clearance joint systematically. The influence of friction coefficient on dynamics response of 4 UPS-UPU mechanism with spherical clearance joint was analyzed. Non-linear characteristics of clearance joint and moving platform were analyzed by Poincare map, phase diagram, and bifurcation diagram. The results show that variation of friction coefficient and clearance value had little effect on stability of the mechanism, but the chaotic phenomenon was found at spherical clearance joint. The research has theoretical guiding significance for improving the dynamic performance and avoiding of chaos of parallel mechanisms including spherical joint clearance. 展开更多
关键词 spatial parallel mechanisms spherical joint clearance dynamic modeling dynamic analysis
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Selection Methodology of High-Cycle Fatigue Analysis Approach for Damage Estimation in Welded Structural Joints 被引量:1
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作者 Skirmantas Pargalgauskas Xiaoli Jiang +1 位作者 Marcel Edelkamp Dingena Schott 《Journal of Marine Science and Application》 CSCD 2022年第4期116-133,共18页
The main purpose of this paper is to provide a summarized general guideline to aid decision making of choosing the type of fatigue analysis approach,best suited for modelling and evaluating high-cycle fatigue damage i... The main purpose of this paper is to provide a summarized general guideline to aid decision making of choosing the type of fatigue analysis approach,best suited for modelling and evaluating high-cycle fatigue damage in welded structural joints.It describes how addition of stress concentration and stress direction information into fatigue assessment methodology affect simulated fatigue damage accumulation results and when it is beneficial or necessary to use a particular fatigue damage estimation approach.The focus is on stress-life curve based approaches,particularly when deciding between variants of nominal,hot-spot or multiaxial fatigue assessment approaches for evaluating fatigue damage within welded joint structures.Evaluation is illustrated through application of proposed methodology to choose and perform fatigue assessment for a non-conventional load-bearing tubular joint structure within a floating lemniscate crane upper arm,which has been observed of being prone to aggressive crack propagation within its welds.Damage within the structure is estimated using two non-optimal fatigue analysis approaches to verify applicability of proposed selection methodology.Results are then summarized through comparative assessment and findings are discussed based on what leads to result changes within each fatigue damage analysis approach. 展开更多
关键词 Fatigue analysis Multiaxial fatigue Hot-spot fatigue METHODOLOGY Welded joints
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