The fatigue life evaluation of the girth butt weld within the welded cast steel joint was studied based on the extrapolation notch stress method.Firstly,the mesh sensitivity of the finite element model of the welded c...The fatigue life evaluation of the girth butt weld within the welded cast steel joint was studied based on the extrapolation notch stress method.Firstly,the mesh sensitivity of the finite element model of the welded cast steel joint was analyzed to determine the optimal mesh size.Based on the stress field analysis of the finite element model of the welded cast steel joint at the weld toe and weld root,the sharp model of the extrapolation notch stress method was applied to derive the effective notch stress of the rounded model belonging to the effective notch stress method,in which the key problem is to calculate the extrapolation point C,and the extrapolation point C has an exponential function relationship with the geometric parameters of the welded cast steel joint.By setting different values of geometric parameters,the corresponding value of parameter C is calculated,and then the functional relationship between the extrapolation point C and the geometric parameters can be obtained by the multiple linear regression analysis.Meanwhile,the fatigue life evaluation of the girth butt weld within welded cast steel joints based on the effective notch stress was performed according to the guideline recommended by the IIW(International Institute of Welding).The results indicate that the extrapolation notch stress method can effectively simplify the process of calculating the effective notch stress and accurately evaluate the fatigue life of the girth butt weld within welded cast steel joints.展开更多
At present, most shale gas exploration and development areas in China are difficult to provide sufficient and effective production data to support economic evaluation, since they are still in the initial stage of low ...At present, most shale gas exploration and development areas in China are difficult to provide sufficient and effective production data to support economic evaluation, since they are still in the initial stage of low exploration level. In addition, ecological and environmental factors are not taken into account in the evaluation process, which does not meet the needs of green energy development of China. Aiming at above problems, the dynamic economic evaluation method of shale gas resources based on calculus principle is proposed. The Arps hyperbolic decreasing curve model will be used in the evaluation of single shale gas well production, which can evaluate single well production of shale gas by fitting the existing dynamic production data to generate the production decreasing curve. Therefore, the variation regularity of the cumulative production of single well shale gas within the study area can be obtained by the model mentioned above. According to the variation regularity of the cumulative production obtained from the Arps hyperbolic decreasing curve model, the recovery period of single well cost, ultimate economic life and the ultimate economic resource can be evaluated dynamically by analyzing the variation regularity of the cumulative sales revenue and cumulative input cost of single shale gas well. Then the evaluation result can be further extend to the whole evaluation areas, in order to analyze shale gas resources ’ economic value in evaluation regions under different shale gas price conditions. The results of the above evaluation methods are not only conducive to improving the economic benefits of relative shale gas development enterprises, but also provide a basis for the national energy strategy deployment.展开更多
为协调生活、生产和生态空间的用地矛盾,解决数据驱动法在识别城市“三生空间”方面存在的判别不准确和数据覆盖范围不够等问题,提出了一种能够精准识别“三生空间”功能的方法。基于数据驱动法,结合POI(point of interest)、AOI(area o...为协调生活、生产和生态空间的用地矛盾,解决数据驱动法在识别城市“三生空间”方面存在的判别不准确和数据覆盖范围不够等问题,提出了一种能够精准识别“三生空间”功能的方法。基于数据驱动法,结合POI(point of interest)、AOI(area of interest)和遥感等多源异构数据的多特征信息,分析在功能评价体系和分类模型中将不同数据源作为特征因子时的识别精度与尺度效应。以高原城市昆明市五华区建成范围为实验对象,研究结果表明:基于多源地理数据的识别准确率达到92%和94%。多源数据的多特征信息能够明显提升城市功能区的识别精度,为城市功能区精准识别提供了新的方法,能够在更小的尺度上为国土空间规划提供数据与方法支撑。展开更多
目的:对国内外结直肠癌生存者重新融入正常生活相关研究进行范围综述,了解结直肠癌生存者重新融入正常生活研究现状。方法:计算机检索建库至2023年11月中国知网、万方数据库、维普数据库、中国生物医学文献数据库、PubMed、MedLine、CIN...目的:对国内外结直肠癌生存者重新融入正常生活相关研究进行范围综述,了解结直肠癌生存者重新融入正常生活研究现状。方法:计算机检索建库至2023年11月中国知网、万方数据库、维普数据库、中国生物医学文献数据库、PubMed、MedLine、CINAHL、the Corchrane Library及Web of Science中发表的中英文文献,并对其进行汇总、分析。结果:共纳入25篇文献,汇总和整理得出结直肠癌生存者重新融入正常生活现状不容乐观且受诸多因素的影响,其中年龄、治疗方式是其重要的影响因素。相关理论框架包括成人教育理论、社会戏剧模型、社会疏离概念模型、生物-心理-社会模型、工作生活恢复路径。评估工具分为3个方面,即重返工作、重返家庭、重返社会。干预方法主要包括运动干预、职业康复干预、早期适应干预、家庭赋权方案干预以及健康教育5种类型。结论:结直肠癌生存者重新融入正常生活相关理论的适宜性有待进一步验证,未来研究应重视重返社会与家庭评估的发展和完善,并在理论框架的指导下探索有效的干预方法,为提高结直肠癌生存者重新融入正常生活提供依据。展开更多
Pneumatic actuators and electric actuators have almost been applied to all manufacturing industries. The two kinds of actuators can replace each other in most fields, such as the point to point transmission occasion a...Pneumatic actuators and electric actuators have almost been applied to all manufacturing industries. The two kinds of actuators can replace each other in most fields, such as the point to point transmission occasion and some rotating occasions. However, there are very few research results about the advantages and disadvantages of two kinds of actuators under the same working conditions so far. In this paper, a novel comprehensive assessment method, named as overall life cycle comprehensive assessment （OLCCA）, is proposed for comparison and assessment of pneumatic and electric actuators. OLCCA contains mechanical properties evaluation （MPE）, life cycle cost analysis based on users （LCCABOU） and life cycle environmental impact analysis （LCEIA） algorithm in order to solve three difficult problems： mechanical properties assessment, cost analysis and environmental impact assessment about actuators. The mechanical properties evaluation of actuators is a multi-objective optimization problem. The fuzzy data quantification and information entropy methods are combined to establish MPE algorithm of actuators. Two kinds of pneumatic actuators and electric actuators with similar bearing capacity and similar work stroke were taken for example to verify the correctness of MPE algorithm. The case study of MPE algorithm for actuators verified its correctness. LCCABOU for actuators is also set up. Considering cost complex structure of pneumatic actuators, public device cost even method （PDCEM） is firstly presented to solve cost division of public devices such as compressors, aftercooler, receivers, etc. LCCABOU method is also effective and verified by the three groups of pneumatic actuators and electric actuators. Finally, LCEIA model of actuators is established for the environmental impact assessment of actuators. LCEIA data collection method and model establishment procedure for actuators are also put forward. With Simapro 7, LCEIA comparison results of six actuators can be obtained： Fossil fuels are the major environmental factor of pneumatic and electric actuators; Environmental impact of electric actuator is large than one of pneumatic actuator under the similar mechanical properties and working conditions of pneumatic and electric actuators. The results are correct and correspond with the actual mechanical properties of actuators. This paper proposes a comprehensive evaluation method of the actuators, which can solve the critical problem that similar electromechanical products are very difficult to be compared with each other from the angle of performance, cost and environment impact.展开更多
通过对BPZ 220/5 W JA55型阳光球泡灯进行额定功率下40℃和60℃温度应力加速寿命实验,分析了该款LED球泡灯的失效机理.通过推导激活能计算公式,建立了计算光衰激活能的理论模型,给出了测试LED球泡灯光衰激活能方法.通过实验测定该款球...通过对BPZ 220/5 W JA55型阳光球泡灯进行额定功率下40℃和60℃温度应力加速寿命实验,分析了该款LED球泡灯的失效机理.通过推导激活能计算公式,建立了计算光衰激活能的理论模型,给出了测试LED球泡灯光衰激活能方法.通过实验测定该款球泡灯的光衰激活能数值为0.67 eV.展开更多
基金The National Key Research and Development Program of China(No.2017YFC0805100),the National Natural Science Foundation of China(No.51578137)the Priority Academic Program Development of Jiangsu Higher Education Institutions,the Open Research Fund Program of Jiangsu Key Laboratory of Engineering Mechanics.
文摘The fatigue life evaluation of the girth butt weld within the welded cast steel joint was studied based on the extrapolation notch stress method.Firstly,the mesh sensitivity of the finite element model of the welded cast steel joint was analyzed to determine the optimal mesh size.Based on the stress field analysis of the finite element model of the welded cast steel joint at the weld toe and weld root,the sharp model of the extrapolation notch stress method was applied to derive the effective notch stress of the rounded model belonging to the effective notch stress method,in which the key problem is to calculate the extrapolation point C,and the extrapolation point C has an exponential function relationship with the geometric parameters of the welded cast steel joint.By setting different values of geometric parameters,the corresponding value of parameter C is calculated,and then the functional relationship between the extrapolation point C and the geometric parameters can be obtained by the multiple linear regression analysis.Meanwhile,the fatigue life evaluation of the girth butt weld within welded cast steel joints based on the effective notch stress was performed according to the guideline recommended by the IIW(International Institute of Welding).The results indicate that the extrapolation notch stress method can effectively simplify the process of calculating the effective notch stress and accurately evaluate the fatigue life of the girth butt weld within welded cast steel joints.
文摘At present, most shale gas exploration and development areas in China are difficult to provide sufficient and effective production data to support economic evaluation, since they are still in the initial stage of low exploration level. In addition, ecological and environmental factors are not taken into account in the evaluation process, which does not meet the needs of green energy development of China. Aiming at above problems, the dynamic economic evaluation method of shale gas resources based on calculus principle is proposed. The Arps hyperbolic decreasing curve model will be used in the evaluation of single shale gas well production, which can evaluate single well production of shale gas by fitting the existing dynamic production data to generate the production decreasing curve. Therefore, the variation regularity of the cumulative production of single well shale gas within the study area can be obtained by the model mentioned above. According to the variation regularity of the cumulative production obtained from the Arps hyperbolic decreasing curve model, the recovery period of single well cost, ultimate economic life and the ultimate economic resource can be evaluated dynamically by analyzing the variation regularity of the cumulative sales revenue and cumulative input cost of single shale gas well. Then the evaluation result can be further extend to the whole evaluation areas, in order to analyze shale gas resources ’ economic value in evaluation regions under different shale gas price conditions. The results of the above evaluation methods are not only conducive to improving the economic benefits of relative shale gas development enterprises, but also provide a basis for the national energy strategy deployment.
文摘为协调生活、生产和生态空间的用地矛盾,解决数据驱动法在识别城市“三生空间”方面存在的判别不准确和数据覆盖范围不够等问题,提出了一种能够精准识别“三生空间”功能的方法。基于数据驱动法,结合POI(point of interest)、AOI(area of interest)和遥感等多源异构数据的多特征信息,分析在功能评价体系和分类模型中将不同数据源作为特征因子时的识别精度与尺度效应。以高原城市昆明市五华区建成范围为实验对象,研究结果表明:基于多源地理数据的识别准确率达到92%和94%。多源数据的多特征信息能够明显提升城市功能区的识别精度,为城市功能区精准识别提供了新的方法,能够在更小的尺度上为国土空间规划提供数据与方法支撑。
文摘目的:对国内外结直肠癌生存者重新融入正常生活相关研究进行范围综述,了解结直肠癌生存者重新融入正常生活研究现状。方法:计算机检索建库至2023年11月中国知网、万方数据库、维普数据库、中国生物医学文献数据库、PubMed、MedLine、CINAHL、the Corchrane Library及Web of Science中发表的中英文文献,并对其进行汇总、分析。结果:共纳入25篇文献,汇总和整理得出结直肠癌生存者重新融入正常生活现状不容乐观且受诸多因素的影响,其中年龄、治疗方式是其重要的影响因素。相关理论框架包括成人教育理论、社会戏剧模型、社会疏离概念模型、生物-心理-社会模型、工作生活恢复路径。评估工具分为3个方面,即重返工作、重返家庭、重返社会。干预方法主要包括运动干预、职业康复干预、早期适应干预、家庭赋权方案干预以及健康教育5种类型。结论:结直肠癌生存者重新融入正常生活相关理论的适宜性有待进一步验证,未来研究应重视重返社会与家庭评估的发展和完善,并在理论框架的指导下探索有效的干预方法,为提高结直肠癌生存者重新融入正常生活提供依据。
基金Supported by Doctoral Foundation of Henan Polytechnic University(Grant No.B2012-101)Opening Project of Key Laboratory of Precision Manufacturing Technology and Engineering of Henan Polytechnic University,China(Grant No.PMTE201318A)Henan Provincial Science and Technology Research Projects of Education Department of China(Grant No.14B460033)
文摘Pneumatic actuators and electric actuators have almost been applied to all manufacturing industries. The two kinds of actuators can replace each other in most fields, such as the point to point transmission occasion and some rotating occasions. However, there are very few research results about the advantages and disadvantages of two kinds of actuators under the same working conditions so far. In this paper, a novel comprehensive assessment method, named as overall life cycle comprehensive assessment （OLCCA）, is proposed for comparison and assessment of pneumatic and electric actuators. OLCCA contains mechanical properties evaluation （MPE）, life cycle cost analysis based on users （LCCABOU） and life cycle environmental impact analysis （LCEIA） algorithm in order to solve three difficult problems： mechanical properties assessment, cost analysis and environmental impact assessment about actuators. The mechanical properties evaluation of actuators is a multi-objective optimization problem. The fuzzy data quantification and information entropy methods are combined to establish MPE algorithm of actuators. Two kinds of pneumatic actuators and electric actuators with similar bearing capacity and similar work stroke were taken for example to verify the correctness of MPE algorithm. The case study of MPE algorithm for actuators verified its correctness. LCCABOU for actuators is also set up. Considering cost complex structure of pneumatic actuators, public device cost even method （PDCEM） is firstly presented to solve cost division of public devices such as compressors, aftercooler, receivers, etc. LCCABOU method is also effective and verified by the three groups of pneumatic actuators and electric actuators. Finally, LCEIA model of actuators is established for the environmental impact assessment of actuators. LCEIA data collection method and model establishment procedure for actuators are also put forward. With Simapro 7, LCEIA comparison results of six actuators can be obtained： Fossil fuels are the major environmental factor of pneumatic and electric actuators; Environmental impact of electric actuator is large than one of pneumatic actuator under the similar mechanical properties and working conditions of pneumatic and electric actuators. The results are correct and correspond with the actual mechanical properties of actuators. This paper proposes a comprehensive evaluation method of the actuators, which can solve the critical problem that similar electromechanical products are very difficult to be compared with each other from the angle of performance, cost and environment impact.
