检索结果-南通市图书馆

Regular truss structure model equivalent to continuum structure

International Journal of Agricultural and Biological Engineering 2015年第5期8卷 151-161页

作者： Won Choi JeongJae lee Seongsoo yoon Department of Rural Systems Engineering College of Agriculture and Life SciencesSeoul National UniversitySeoul 151-921South Korea Department of Rural Systems Engineering Research Institute of Agriculture and Life SciencesCollege of Agriculture and Life SciencesSeoul National UniversitySeoul 151-921South Korea Department.of Agricultural and Rural Engineering College of AgricultureLife and Environments SciencesChungbuk National UniversityChungbuk 362-763South Korea

It is difficult to solve the structural problems related to agricultural engineering,due to the wide ranges of the means of related variables and complex structural *** these reasons,discrete models are required that are able to replace or simplify solid structure components used in traditional analysis ***,the objective of this study was to develop a regular truss structure model that behaves the same way as a solid *** was assumed that if a unit element consists of truss elements with each hinge at the end of the element and the size of the element is infinitesimal,the stress distribution and displacement field will be constant throughout the domain of the unit ***,the behavior of the truss element was assumed to be in a linear state in a two-dimensional *** law of energy conservation,based on the theory of elasticity,was applied to determine the equilibrium conditions between discretized and solid *** restrictive condition that we obtained revealed that applications are limited to only ideal elastic materials with a Poisson’s ratio of 1 to *** volumetric ratio of the equivalent truss to the continuum structures was 3:1,regardless of the size or number of the *** calculate the internal stress and strain of the unit element,the geometric relationships of each truss member,which has its own role against different stress directions,were *** calculated von Misses stresses were used to verify this *** concentrations,as explained based on Saint Venant’s principle,were also observed in the equivalent truss structure *** main stress paths,indicating the areas where reinforcement bars should be placed,were successfully shown without the requirement that each element be transformed in the direction of principal stress;this was done by eliminating elements with only compressive and near-zero stresses.

关键词： structural analysis regular mesh equivalent truss structure model discretized element energy method

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

Epidemic obesity in children and adolescents:risk factors and prevention

引用

Frontiers of Medicine 2018年第6期12卷 658-666页

作者： Eun Young lee Kun-Ho yoon Division of Endocrinology and Metabolism Department of Internal MedicineSeoul St.Mary's HospitalCollege of MedicineThe Catholic University of KoreaSeoul 06591Korea Institute of Catholic Ubiquitous Health Care The Catholic University of KoreaSeoul 06591Korea

The prevalence of obesity among children and adolescents (aged 2-18 years) has increased rapidly, with more than 100 million affected in 2015. Moreover, the epidemic of obesity in this population has been an important public health problem in developed and developing countries for the following reasons. Childhood and adolescent obesity tracks adulthood obesity and has been implicated in many chronic diseases, including type 2 diabetes, hypertension, and cardiovascular disease. Furthermore, childhood and adolescent obesity is linked to adulthood mortality and premature death. Although an imbalance between caloric intake and physical activity is a principal cause of childhood and adolescent obesity, environmental factors are exclusively important for development of obesity among children and adolescents. In addition to genetic and biological factors, socioenvironmental factors, including family, school, community, and national policies, can play a crucial role. The complexity of risk factors for developing obesity among children and adolescents leads to difficulty in treatment for this population. Many interventional trials for childhood and adolescent obesity have been proven ineffective. Therefore, early identification and prevention is the key to control the global epidemic of obesity. Given that the proportion of overweight children and adolescents is far greater than that of obesity, an effective prevention strategy is to focus on overweight youth, who are at high risk for developing obesity. Multifaceted, comprehensive strategies involving behavioral, psychological, and environmental risk factors must also be developed to prevent obesity among children and adolescents.

关键词： adolescents children epidemiology obesity prevention risk factor

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

New prognostic model for patients with advanced gastric cancer:Fluoropyrimidine/platinum doublet for first-line chemotherapy

引用

World Journal of Gastroenterology 2021年第48期27卷 8357-8369页

作者： Dong-Hoe Koo Min-Hee Ryu Mi-Yeon lee Mee-sun Moon yoon-Koo Kang Division of Hematology/Oncology Department of Internal MedicineKangbuk Samsung HospitalSungkyunkwan University School of MedicineSeoul 03181South Korea Department of Oncology Asan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505South Korea Division of Biostatistics Department of R&D ManagementKangbuk Samsung HospitalSeoul 03181South Korea

BACKGROUND New prognostic factors have been reported in patients with metastatic or recurrent gastric cancer(MRGC),necessitating modifications to the previous prognostic *** To develop a new model,MRGC patients who received fluoropyrimidines/platinum doublet chemotherapy between 2008 and 2015 were *** A total of 1883 patients was divided into a training set(n=937)and an independent validation set(n=946).RESULTS Multivariate analysis showed that the following six factors were associated with poor overall survival(OS)in the training set:Eastern Cooperative Oncology Group performance score≥2 and bone metastasis(2 points each),peritoneal metastasis,high alkaline phosphatase level,low albumin level,and high neutrophil-lymphocyte ratio(1 point each).A prognostic model was developed by stratifying patients into good(0-1 point),moderate(2-3 points),and poor(≥4 points)risk *** the validation set,the median OS of the three risk groups was 15.8,10.1,and 5.7 mo,respectively,and those differences were significant(P<0.001).CONCLUSION We identified six factors readily measured in clinical practice that are predictive of poor prognosis in patients with *** new model is simpler than the old and more easily predicts OS.

关键词： Stomach neoplasms Chemotherapy Prognosis Validation Gastric cancer

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 Steam-Plasma Igniter for Aluminum Powder Combustion

引用

Plasma Science and Technology 2015年第5期17卷 392-401页

作者： Sanghyup lee Kwanyoung NOH Jihwan LIM Woongsup yoon Mechanical Engineering Department of Yonsei University

High-temperature ignition is essential for the ignition and combustion of energetic metal fuels, including aluminum and magnesium particles which are protected by their high- melting-temperature oxides. A plasma torch characterized by an ultrahigh-temperature plasma plume fulfills such high-temperature ignition conditions. A new steam plasma igniter is designed and successfully validated by aluminum power ignition and combustion tests. The steam plasma rapidly stabilizes in both plasma and steam jet modes. Parametric investigation of the steam plasma jet is conducted in terms of arc strength. A high-speed camera and an oscilloscope method visualize the discharge characteristics, and optical emission spectroscopy measures the thermochemical properties of the plasma jet. The diatomic molecule OH fitting method, the Boltzmann plot method, and short exposure capturing with an intensified charge coupled device record the axial distributions of the rotational gas temperature, excitation temperature, and OH radical distribution, respectively. The excitation temperature at the nozzle tip is near 5500 K, and the gas temperature is 5400 K.

关键词： steam plasma igniter aluminum emission spectroscopy energetic metal fuels powder ignition and combustion optical

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

Thermo-physical Characteristics of Nickel-coated Aluminum Powder as a Function of Particle Size and Oxidant

引用

Chinese Journal of Mechanical Engineering 2016年第6期29卷 1244-1255页

作者： lee Sanghyup NOH Kwanyoung LIM Jihwan yoon Woongsup Advanced Energy and Propulsion Laboratory Department of Mechanical Engineering Yonsei University Missile System Integration / propulsion Center Hanwha Corp.

Aluminum particles 15-25 μm in size are widely used in fuel propellants and underwater propulsion systems in national defense research. However, these particles are covered with an aluminum oxide film, which has a high melting point, so ignition is difficult. To improve the ignitability of high-energy aluminum powder and to understand the reaction phenomenon as a function of particle size（15-25 μm, 74-105 μm, and 2.38 mm） and oxidizer（air, CO2, and argon）, the natural oxide films are chemically removed. The particles are then coated with nickel using an electro-less method. The degree of nickel deposition is confirmed qualitatively and quantitatively through surface analysis using scanning electron microscopy/energy dispersive spectroscopy. To characterize the nickel coatings, elemental analysis is also conducted by using X-ray diffraction. Thermogravimetric analysis/differential scanning calorimetry （TGA/DSC） enable comparisons between the uncoated and coated aluminum, and the reaction process are investigated through fine structural analysis of the particle surfaces and cross sections. There are little difference in reactivity as a function of oxidant type. However, a strong exothermic reaction in the smaller nickel-coated aluminum particles near the melting point of aluminum accelerates the reaction of the smaller particles. Explanation of the reactivity of the nickel-coated aluminum depending on the particle sizes is attempted.

关键词： nickel-coated aluminum TGA/DSC aluminum ignition combustion intermetallic reaction

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

New approaches to gastric cancer staging:Beyond endoscopic ultrasound,computed tomography and positron emission tomography

引用

World Journal of Gastroenterology 2014年第38期20卷 13783-13790页

作者： Hyuk yoon Dong Ho lee Department of Internal Medicine Seoul National University Bundang Hospital Department of Internal Medicine and Liver Research Institute Seoul National University College of Medicine

Currently, there is no single gold standard modality for staging of gastric cancer and several methods have been used complementarily in the each clinical situation. To make up for the shortcomings of conventional modalities such as endoscopic ultrasound, computed tomography and 18F-fluoro-2-deoxyglucose positron emission tomography, numerous attempts with new approaches have been made for gastric cancer staging. For T staging, magnifying endoscopy with narrow-band was evaluated to differentiate mucosal cancer from submucosal cancer. Single/double contrast-enhanced ultrasound and diffusion-weighted magnetic resonance imaging were also tried to improve diagnostic accuracy of gastric cancer. For intraoperative staging with sentinel node mapping, indocyanine green infrared and fluorescence imaging was introduced. In addition, to detect micrometastasis, real-time reverse transcription-polymerase chain reaction system with multiple markers was studied. Staging laparoscopy using 5-aminolevulinic acid-mediated photodynamic diagnosis and percutaneous diagnostic peritoneal lavage were also evaluated. However, most studies reporting new staging methods is preliminary and further studies for validation in clinical practice are needed. In this mini-review, we discuss new progress in gastric cancer staging. Especially, we focus on new diagnostic approach to gastric cancer staging beyond the conventional modalities and briefly review the remarkable clinical results of the studies published over the past three years.

关键词： Gastric cancer Neoplasm staging Diagnostic accuracy New methods New approaches

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

Gender differences in ghrelin, nociception genes, psychological factors and quality of life in functional dyspepsia

引用

World Journal of Gastroenterology 2017年第45期23卷 8053-8061页

作者： yoon Jin Choi Young Soo Park Nayoung Kim Yong sung Kim sun Min lee Dong Ho lee Hyun Chae Jung Department of Internal Medicine Seoul National University Bundang Hospital Department of Internal Medicine and Liver Research Institute Seoul National University College of Medicine Department of Gastroenterology Wonkwang Digestive Disease Research InstituteWonkwang University Sanbon Hospital

AIM to evaluate gender differences in the aspect of ghrelin,nociception-related genes and psychological aspects and the quality of life(Qo L) in Korean functional dyspepsia(FD) *** Total of 191 persons were prospectively enrolled between March 2013 and May 2016 in Seoul National Bundang Hospital,and classified into control and FD group based on ROME Ⅲ criteria. Questionnaire included assessment for dyspepsia symptoms,Qo L and anxiety or depression. Preproghrelin and nociception genes in the gastric mucosa and plasma acyl/des-acyl ghrelin were measured. RESULTS Lower level of plasma acyl ghrelin in FD patients compared to control was significant only in male(15.9 fmol/m L vs 10.4 fmol/m L,P = 0.017). Significantly higher m RNA expressions of nerve growth factor and transient receptor potential vanilloid receptor 1 were observed in male(P = 0.002 and P = 0.014,respectively) than in female. In contrast,female FD patients had a higher anxiety and depression score than male FD(P = 0.029),and anxiety score was correlated with epigastric pain only in female FD patients(female: Spearman rho = 0.420,P = 0.037). The impairment of overall Qo L was more prominent in female FD patients than male patients(5.4 ± 0.3 vs 6.5 ± 0.3,P = 0.020). CONCLUSION Gender differences of ghrelin and nociception-related genes in male and psychological factors in female underlie FD symptoms. More careful assessment of psychological or emotional status is required particularly for the female FD patients.

关键词： Functional dyspepsia Gender differences Quality of life

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

Investigations of an Air Starting Motor of Marine Medium-Speed Diesel Engine with Numerical Analyses

引用

Journal of Thermal Science 2010年第2期19卷 148-153页

作者： Yeon Won lee yoon Hwan Choi Deog Hee Doh Division of Mechanical Eng. Pukyong National Univ.San 100 Division of Mechanical and Information Eng.

The marine medium-speed diesel engines are started by two methods;one is the electric motors,and the other air starting *** though air starting motor is dependent of the engine types and sizes,it has been widely used in this area due to its simplicity,convenience and *** purpose of this paper is to give the designing parameters in order to make a proper "Air Starting Motor" using *** aerodynamic approaches were given to understand the internal flow characteristics of the air starting *** addition,we have carried out the investigation of effects of tip *** the calculations the tip clearance of air starting motor has been varied between 0,2.8,4.3 and 5.7% of blade *** results of computation are the tip clearance increased to 2.8%,the torque decreased 24%,and there was no more large changes when the clearances increased to 4.3% and 5.7%.

关键词： Medium-Speed Diesel Engine Air Starting Motor CFD Tip Clearance Influences

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

Single-cell manipulation by two-dimensional micropatterning

引用

Journal of Innovative Optical Health Sciences 2024年第1期17卷 45-59页

作者： Xuehe Ma Haimei Zhang Shiyu Deng Qiushuo sun Qingsong Hu Yuhang Pan Fen Hu Imshik lee Fulin Xing Leiting Pan The Key Laboratory of Weak-Light Nonlinear Photonics of Education Ministry School of Physics and TEDA Institute of Applied Physics Nankai University Tianjin 300071P.R.China State Key Laboratory of Medicinal Chemical Biology Frontiers Science Center for Cell Responses College of Life Sciences Nankai University Tianjin 300071P.R.China Collaborative Innovation Center of Extreme Optics Shanxi University TaiyuanShanxi 030006P.R.China Shenzhen Research Institute of Nankai University Shenzhen Guangdong 518083P.R.China

Cells are highly sensitive to their geometrical and mechanical microenvironment that directly regulate cell shape,cytoskeleton and organelle,as well as the nucleus morphology and genetic *** emerging two-dimensional micropatterning techniques offer powerful tools to construct controllable and well-organized microenvironment for single-cell level investigations with qualitative analysis,cellular standardization,and in vivo environment ***,we provide an overview of the basic principle and characteristics of the two most widely-used micropatterning techniques,including photolithographic micropatterning and soft lithography ***,we summarize the application of micropatterning technique in controlling cytoskeleton,cell migration,nucleus and gene expression,as well as intercellular communication.

关键词： Two-dimensional micropatterning cytoskeleton cell migration extracellular matrix intercellular communication gene expression

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

Crack simulation and probability analysis using irregular truss structure modeling equivalent to a continuum structure

引用

International Journal of Agricultural and Biological Engineering 2017年第1期10卷 234-247页

作者： Won Choi Seongsoo yoon JeongJae lee Dept.of Rural Systems Engineering College of Agriculture and Life SciencesSeoul National UniversitySeoul 151-921South Korea Dept.of Agricultural and Rural Engineering College of AgricultureLife and Environments SciencesChungbuk National UniversityChungbuk 362-763South Korea Dept.of Rural Systems Engineering Research Institute of Agriculture and Life SciencesCollege of Agriculture and Life SciencesSeoul National UniversitySeoul 151-921South Korea

The problems related to agricultural structure engineering for crack simulation and reliability analysis are complicated because its variables contain wide ranges of mean and standard *** paper describes an integrated model to perform crack simulation and reliability analysis of a continuum *** structure is assumed to be under a two-dimensional plane stress and the deformation is infinitesimal.A truss structure model that has the same behaviour as a continuum structure was developed using irregular triangle truss components where each element consists of two hinges with an axial degree of freedom at both of their ends.A Monte-Carlo simulation(MCS)was adopted for the reliability *** the length of one side of the irregular triangle mesh is shorter than the thickness of the structure,the slenderness associated with compressive failure needs to be examined only for the short *** that reason,the failure criterion suitable for the equivalent truss structure model was established by checking only axial stresses acting on truss *** nodes of the equivalent truss structure model for the structural analysis in this study consist of hinges,development of plastic hinges that occurred during crack propagation were not considered in this *** simulate the development of crack,truss members over allowable stresses of tension or compression among truss members with the largest amount of stress at each completed structural analysis time step were sequentially *** irregular triangle meshes have an uncertainty in themselves to compare with regular meshes,the equivalent truss structure model could describe crack propagation more *** failure probabilities of structures under various loads and boundary conditions had good agreement with the analytical solutions directly solved from the limit state equations expressed in the form of moments.

关键词： crack simulation probability analysis irregular truss structure model failure criteria Monte Carlo simulation

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

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：