As the take-off of China’s macro economy,as well as the rapid development of infrastructure construction,real estate industry,and highway logistics transportation industry,the demand for heavy vehicles is increasing ...As the take-off of China’s macro economy,as well as the rapid development of infrastructure construction,real estate industry,and highway logistics transportation industry,the demand for heavy vehicles is increasing rapidly,the competition is becoming increasingly fierce,and the digital transformation of the production line is imminent.As one of themost important components of heavy vehicles,the transmission front andmiddle case assembly lines have a high degree of automation,which can be used as a pilot for the digital transformation of production.To ensure the visualization of digital twins(DT),consistent control logic,and real-time data interaction,this paper proposes an experimental digital twin modeling method for the transmission front and middle case assembly line.Firstly,theDT-based systemarchitecture is designed,and theDT model is created by constructing the visualization model,logic model,and data model of the assembly line.Then,a simulation experiment is carried out in a virtual space to analyze the existing problems in the current assembly line.Eventually,some improvement strategies are proposed and the effectiveness is verified by a new simulation experiment.展开更多
In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubi...In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubic spline numerical model(Spline Model for short),which is with a quasi-Lagrangian time-split integration scheme of fitting cubic spline/bicubic surface to all physical variable fields in the atmospheric equations on spherical discrete latitude-longitude mesh.A new algorithm of"fitting cubic spline—time step integration—fitting cubic spline—……"is developed to determine their first-and2nd-order derivatives and their upstream points for time discrete integral to the governing equations in Spline Model.And the cubic spline function and its mathematical polarities are also discussed to understand the Spline Model’s mathematical foundation of numerical analysis.It is pointed out that the Spline Model has mathematical laws of"convergence"of the cubic spline functions contracting to the original functions as well as its 1st-order and 2nd-order derivatives.The"optimality"of the 2nd-order derivative of the cubic spline functions is optimal approximation to that of the original functions.In addition,a Hermite bicubic patch is equivalent to operate on a grid for a 2nd-order derivative variable field.Besides,the slopes and curvatures of a central difference are identified respectively,with a smoothing coefficient of 1/3,three-point smoothing of that of a cubic spline.Then the slopes and curvatures of a central difference are calculated from the smoothing coefficient 1/3 and three-point smoothing of that of a cubic spline,respectively.Furthermore,a global simulation case of adiabatic,non-frictional and"incompressible"model atmosphere is shown with the quasi-Lagrangian time integration by using a global Spline Model,whose initial condition comes from the NCEP reanalysis data,along with quasi-uniform latitude-longitude grids and the so-called"shallow atmosphere"Navier-Stokes primitive equations in the spherical coordinates.The Spline Model,which adopted the Navier-Stokes primitive equations and quasi-Lagrangian time-split integration scheme,provides an initial ideal case of global atmospheric circulation.In addition,considering the essentially non-linear atmospheric motions,the Spline Model could judge reasonably well simple points of any smoothed variable field according to its fitting spline curvatures that must conform to its physical interpretation.展开更多
Both sea battles and testing of ship in underwater explosions reveal unacceptably poor anti-shock performance of important shipboard equipment. Anti-shock performance of shipboard equipment is a significant factor det...Both sea battles and testing of ship in underwater explosions reveal unacceptably poor anti-shock performance of important shipboard equipment. Anti-shock performance of shipboard equipment is a significant factor determining fighting strength and survivability. The anti-shock performance of a shipboard gear case based on BV043/85 was investigated using numerical simulation. A geometric model of the gear case was built using MDT software and meshed in HyperMesh software, and then the finite element model of the gear case was formed. Using ABAQUS software, the anti-shock performance of the gear case was simulated. First, shock response of typical regions of gear case was determined. Next, some generalizations were made about the anti-shock performance of the gear case by analyzing the Mises stress of typical regions varied with shock inputs. Third, weak regions were determined from simulation results. The threshold values of shock resistance of the gear case at different impulse widths were obtained through interpolating the numerical simulation results selected from the most dangerous spot. This research provides a basis for further optimization of the design of gear cases.展开更多
BACKGROUND Fewer than 200 cases of diaphragmatic tumors have been reported in the past century. Diaphragmatic hemangiomas are extremely rare. Only nine cases have been reported in English literature to date. We report...BACKGROUND Fewer than 200 cases of diaphragmatic tumors have been reported in the past century. Diaphragmatic hemangiomas are extremely rare. Only nine cases have been reported in English literature to date. We report a case of cavernous hemangioma arising from the diaphragm. Pre-operative three-dimensional(3D)simulation and minimal invasive thoracoscopic excision were performed successfully, and we describe the radiologic findings and the surgical procedure in the following article.CASE SUMMARY A 40-year-old man was referred for further examination of a mass over the right basal lung without specific symptoms. Contrast-enhanced computed tomography revealed a poorly-enhanced lesion in the right basal lung, abutting to the diaphragm, measuring 3.1 cm × 1.5 cm in size. The mediastinum showed a clear appearance without evidence of abnormal mass or lymphadenopathy. A preoperative 3D image was reconstructed, which revealed a diaphragmatic lesion. Video-assisted thoracic surgery was performed, and a red papillary tumor was found, originating from the right diaphragm. The tumor was resected, and the pathological diagnosis was cavernous hemangioma.CONCLUSION In this rare case of diaphragmatic hemangioma, 3D image simulation was helpful for the preoperative evaluation and surgical decision making.展开更多
Large-scale sand fracturing is a necessary means in the efficient exploitation of shale gas/oil.However,in the process of fracturing operation,the sand carrying fluid and proppant easily causes scouring and wear to pr...Large-scale sand fracturing is a necessary means in the efficient exploitation of shale gas/oil.However,in the process of fracturing operation,the sand carrying fluid and proppant easily causes scouring and wear to production strings,especially the casing perforation system,which damage the wellbore integrity and deformation to affect the subsequent fracturing.For this problem,taking the actual construction conditions and perforation technology of an oilfield in western China as an example,the structural parameters of the downhole string were measured and the wall thickness reduction model of casing perforation suitable for large-displacement sand fracturing in horizontal well section was established.With software ANSYS-FLUENT,the casing perforation erosion under the conditions of different displacements,sand content and perforation sand-passing quantity in the process of sand fracturing was simulated and calculated.The influences of three parameters on perforation erosion and expansion were analyzed and the prediction chart of the influences of three main control factors on perforation erosion and expansion was established.The perforation erosion images after fracturing construction were obtained with the downhole eagle perforation logging technology.The logging chart results were compared with the downhole eagle perforation data.The error between the established numerical simulation calculation charts and the real logging data was about 5%,indicating that the simulation charts were the valuable reference.展开更多
目的探讨SBAR(situation,background,assessment and recommendation)沟通联合案例情景模拟教学模式对妇产科见习的医学生的医际沟通和批判性思维的影响。方法2022年11月—2023年5月参加妇产科临床见习培训的临床医学本科生共156人,随...目的探讨SBAR(situation,background,assessment and recommendation)沟通联合案例情景模拟教学模式对妇产科见习的医学生的医际沟通和批判性思维的影响。方法2022年11月—2023年5月参加妇产科临床见习培训的临床医学本科生共156人,随机分成观察组和对照组。对照组应用传统的见习教学模式,针对医际沟通的教学以授课和床旁观察形式进行。观察组医学生入科时进行SBAR沟通模式联合案例情景模拟教学,其余教学同对照组。比较两组见习生出科考核成绩(理论知识成绩和临床技能成绩)、批判性思维能力和对临床见习教学的满意度。结果观察组病史采集和医际沟通成绩优于对照组,差异具有统计学意义(P<0.05),但两组理论知识成绩和临床技能操作成绩无统计学差异(P>0.05)。观察组的批判性思维总分显著高于对照组(P<0.05),其中分析能力、系统化能力、批判性思维自信心和认知成熟度四个维度的得分均高于对照组,差异具有统计学意义(P<0.05),但两组的寻找真相、开放思维和求知欲三个维度的得分差异无统计学意义(P>0.05)。观察组学生对教学满意度高于对照组,差异具有统计学意义(P<0.05)。结论在临床医学本科生妇产科见习阶段引入SBAR沟通模式联合案例情景模拟教学,有利于本科生提高学习兴趣,增强批判性思维能力,提升医际沟通能力,可在各类学科的见习教学中推广。展开更多
目的探讨SEGUE[准备(set the stage,S),信息收集(elicitinformation,E),信息给予(giveinformation,G),理解患者(understandthepatient's/family’sperspective,U),结束问诊(end the encounter,E)]框架情景式案例分析教学法在精神科...目的探讨SEGUE[准备(set the stage,S),信息收集(elicitinformation,E),信息给予(giveinformation,G),理解患者(understandthepatient's/family’sperspective,U),结束问诊(end the encounter,E)]框架情景式案例分析教学法在精神科见习生中的应用效果。方法选取2019年9月—2020年12月在中山大学附属第三医院精神科见习的2016级和2017级5年制临床医学专业医学生为研究对象,共204名,将其随机分为试验组、对照组,各102名。试验组采取SEGUE框架下的情景式案例分析教学法,对照组采取传统的教学方法。2组在课程开始前和见习结束时均采用中文版医患沟通技能评价量表(SEGUE量表)对精神科见习生医患沟通能力进行评分。结果干预前,2组SEGUE量表各维度得分比较,差异无统计学意义(P>0.05)。干预后,2组准备、信息收集、信息给予、理解患者、总分以及人文关怀评分均高于干预前,试验组高于对照组,差异有统计学意义(P<0.001)。结论SEGUE框架下情景式案例分析教学法能很好地提高精神科见习生的医患沟通能力,尤其是共情能力和人文关怀能力,可以作为精神科见习医生的医患沟通教学方法的参考方案。展开更多
基金supported by China National Heavy Duty Truck Group Co.,Ltd.(Grant No.YF03221048P)the Shanghai Municipal Bureau of Market Supervision and Administration(Grant No.2022-35)New Young TeachersResearch Start-Up Foundation of Shanghai Jiao Tong University(Grant No.22X010503668).
文摘As the take-off of China’s macro economy,as well as the rapid development of infrastructure construction,real estate industry,and highway logistics transportation industry,the demand for heavy vehicles is increasing rapidly,the competition is becoming increasingly fierce,and the digital transformation of the production line is imminent.As one of themost important components of heavy vehicles,the transmission front andmiddle case assembly lines have a high degree of automation,which can be used as a pilot for the digital transformation of production.To ensure the visualization of digital twins(DT),consistent control logic,and real-time data interaction,this paper proposes an experimental digital twin modeling method for the transmission front and middle case assembly line.Firstly,theDT-based systemarchitecture is designed,and theDT model is created by constructing the visualization model,logic model,and data model of the assembly line.Then,a simulation experiment is carried out in a virtual space to analyze the existing problems in the current assembly line.Eventually,some improvement strategies are proposed and the effectiveness is verified by a new simulation experiment.
文摘In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubic spline numerical model(Spline Model for short),which is with a quasi-Lagrangian time-split integration scheme of fitting cubic spline/bicubic surface to all physical variable fields in the atmospheric equations on spherical discrete latitude-longitude mesh.A new algorithm of"fitting cubic spline—time step integration—fitting cubic spline—……"is developed to determine their first-and2nd-order derivatives and their upstream points for time discrete integral to the governing equations in Spline Model.And the cubic spline function and its mathematical polarities are also discussed to understand the Spline Model’s mathematical foundation of numerical analysis.It is pointed out that the Spline Model has mathematical laws of"convergence"of the cubic spline functions contracting to the original functions as well as its 1st-order and 2nd-order derivatives.The"optimality"of the 2nd-order derivative of the cubic spline functions is optimal approximation to that of the original functions.In addition,a Hermite bicubic patch is equivalent to operate on a grid for a 2nd-order derivative variable field.Besides,the slopes and curvatures of a central difference are identified respectively,with a smoothing coefficient of 1/3,three-point smoothing of that of a cubic spline.Then the slopes and curvatures of a central difference are calculated from the smoothing coefficient 1/3 and three-point smoothing of that of a cubic spline,respectively.Furthermore,a global simulation case of adiabatic,non-frictional and"incompressible"model atmosphere is shown with the quasi-Lagrangian time integration by using a global Spline Model,whose initial condition comes from the NCEP reanalysis data,along with quasi-uniform latitude-longitude grids and the so-called"shallow atmosphere"Navier-Stokes primitive equations in the spherical coordinates.The Spline Model,which adopted the Navier-Stokes primitive equations and quasi-Lagrangian time-split integration scheme,provides an initial ideal case of global atmospheric circulation.In addition,considering the essentially non-linear atmospheric motions,the Spline Model could judge reasonably well simple points of any smoothed variable field according to its fitting spline curvatures that must conform to its physical interpretation.
文摘Both sea battles and testing of ship in underwater explosions reveal unacceptably poor anti-shock performance of important shipboard equipment. Anti-shock performance of shipboard equipment is a significant factor determining fighting strength and survivability. The anti-shock performance of a shipboard gear case based on BV043/85 was investigated using numerical simulation. A geometric model of the gear case was built using MDT software and meshed in HyperMesh software, and then the finite element model of the gear case was formed. Using ABAQUS software, the anti-shock performance of the gear case was simulated. First, shock response of typical regions of gear case was determined. Next, some generalizations were made about the anti-shock performance of the gear case by analyzing the Mises stress of typical regions varied with shock inputs. Third, weak regions were determined from simulation results. The threshold values of shock resistance of the gear case at different impulse widths were obtained through interpolating the numerical simulation results selected from the most dangerous spot. This research provides a basis for further optimization of the design of gear cases.
文摘BACKGROUND Fewer than 200 cases of diaphragmatic tumors have been reported in the past century. Diaphragmatic hemangiomas are extremely rare. Only nine cases have been reported in English literature to date. We report a case of cavernous hemangioma arising from the diaphragm. Pre-operative three-dimensional(3D)simulation and minimal invasive thoracoscopic excision were performed successfully, and we describe the radiologic findings and the surgical procedure in the following article.CASE SUMMARY A 40-year-old man was referred for further examination of a mass over the right basal lung without specific symptoms. Contrast-enhanced computed tomography revealed a poorly-enhanced lesion in the right basal lung, abutting to the diaphragm, measuring 3.1 cm × 1.5 cm in size. The mediastinum showed a clear appearance without evidence of abnormal mass or lymphadenopathy. A preoperative 3D image was reconstructed, which revealed a diaphragmatic lesion. Video-assisted thoracic surgery was performed, and a red papillary tumor was found, originating from the right diaphragm. The tumor was resected, and the pathological diagnosis was cavernous hemangioma.CONCLUSION In this rare case of diaphragmatic hemangioma, 3D image simulation was helpful for the preoperative evaluation and surgical decision making.
基金support from Sichuan Science and Technology Program(21JCQN0066)supported by National Natural Science Foundation of China(No.51774249).
文摘Large-scale sand fracturing is a necessary means in the efficient exploitation of shale gas/oil.However,in the process of fracturing operation,the sand carrying fluid and proppant easily causes scouring and wear to production strings,especially the casing perforation system,which damage the wellbore integrity and deformation to affect the subsequent fracturing.For this problem,taking the actual construction conditions and perforation technology of an oilfield in western China as an example,the structural parameters of the downhole string were measured and the wall thickness reduction model of casing perforation suitable for large-displacement sand fracturing in horizontal well section was established.With software ANSYS-FLUENT,the casing perforation erosion under the conditions of different displacements,sand content and perforation sand-passing quantity in the process of sand fracturing was simulated and calculated.The influences of three parameters on perforation erosion and expansion were analyzed and the prediction chart of the influences of three main control factors on perforation erosion and expansion was established.The perforation erosion images after fracturing construction were obtained with the downhole eagle perforation logging technology.The logging chart results were compared with the downhole eagle perforation data.The error between the established numerical simulation calculation charts and the real logging data was about 5%,indicating that the simulation charts were the valuable reference.
文摘目的探讨SBAR(situation,background,assessment and recommendation)沟通联合案例情景模拟教学模式对妇产科见习的医学生的医际沟通和批判性思维的影响。方法2022年11月—2023年5月参加妇产科临床见习培训的临床医学本科生共156人,随机分成观察组和对照组。对照组应用传统的见习教学模式,针对医际沟通的教学以授课和床旁观察形式进行。观察组医学生入科时进行SBAR沟通模式联合案例情景模拟教学,其余教学同对照组。比较两组见习生出科考核成绩(理论知识成绩和临床技能成绩)、批判性思维能力和对临床见习教学的满意度。结果观察组病史采集和医际沟通成绩优于对照组,差异具有统计学意义(P<0.05),但两组理论知识成绩和临床技能操作成绩无统计学差异(P>0.05)。观察组的批判性思维总分显著高于对照组(P<0.05),其中分析能力、系统化能力、批判性思维自信心和认知成熟度四个维度的得分均高于对照组,差异具有统计学意义(P<0.05),但两组的寻找真相、开放思维和求知欲三个维度的得分差异无统计学意义(P>0.05)。观察组学生对教学满意度高于对照组,差异具有统计学意义(P<0.05)。结论在临床医学本科生妇产科见习阶段引入SBAR沟通模式联合案例情景模拟教学,有利于本科生提高学习兴趣,增强批判性思维能力,提升医际沟通能力,可在各类学科的见习教学中推广。
文摘目的探讨SEGUE[准备(set the stage,S),信息收集(elicitinformation,E),信息给予(giveinformation,G),理解患者(understandthepatient's/family’sperspective,U),结束问诊(end the encounter,E)]框架情景式案例分析教学法在精神科见习生中的应用效果。方法选取2019年9月—2020年12月在中山大学附属第三医院精神科见习的2016级和2017级5年制临床医学专业医学生为研究对象,共204名,将其随机分为试验组、对照组,各102名。试验组采取SEGUE框架下的情景式案例分析教学法,对照组采取传统的教学方法。2组在课程开始前和见习结束时均采用中文版医患沟通技能评价量表(SEGUE量表)对精神科见习生医患沟通能力进行评分。结果干预前,2组SEGUE量表各维度得分比较,差异无统计学意义(P>0.05)。干预后,2组准备、信息收集、信息给予、理解患者、总分以及人文关怀评分均高于干预前,试验组高于对照组,差异有统计学意义(P<0.001)。结论SEGUE框架下情景式案例分析教学法能很好地提高精神科见习生的医患沟通能力,尤其是共情能力和人文关怀能力,可以作为精神科见习医生的医患沟通教学方法的参考方案。
