To estimate the geometric characteristics, especially wet areas and section areas, of three dimensional numerical conceptual aircraft models, a method based on surface elements is proposed. On the premise that numerou...To estimate the geometric characteristics, especially wet areas and section areas, of three dimensional numerical conceptual aircraft models, a method based on surface elements is proposed. On the premise that numerous surface elements are generated to represent each component surface, a component wet area of the surface is estimated by adding up the areas of such elements that are not covered by any other component surfaces. The elements are also used to get the section polygons of such composite surfaces as the whole aircraft at a given body station, then a section area is approximated with the sum of trapezoidal areas between such sides of polygons that are not covered by any other component and a reference axis. Practical application to a computer aided aircraft conceptual design system shows that the methed is applicable to different kinds of conceptual aircraft models and its precision is satisfying to the conceptual design.展开更多
The possibility of the electric-hydraulic chattering technology and its application in the cold extrusion were presented.The conventional and electric-hydraulic chattering assisted backward extrusion processes were pe...The possibility of the electric-hydraulic chattering technology and its application in the cold extrusion were presented.The conventional and electric-hydraulic chattering assisted backward extrusion processes were performed on 6061 aluminum alloy billets at room temperature.The experimental results showed that 5.65% reduction in the extrusion load was attained if the die and ejector were vibrated at a frequency of 100 Hz and amplitude of 0.013 mm in the longitudinal direction.The friction coefficient at the billet and tool system interface determined from the finite element analysis（FEA） decreased from 0.2 without chattering to 0.1 with application of electric-hydraulic chattering.The higher values of instantaneous velocity and direction change of material flow were achieved during the chattering assisted backward extrusion process.The strain distribution of the chattering assisted backward extrusion billet revealed lower maximum strain and smoother strain distribution in comparison with that produced by the conventional extrusion method.展开更多
In this paper,a nonconforming rectangular plate element,the modified incomplete biquadratic plate element,is considered. The asympotic optimal L~∞-error estimate is obtained for the plate bending problem. This proof ...In this paper,a nonconforming rectangular plate element,the modified incomplete biquadratic plate element,is considered. The asympotic optimal L~∞-error estimate is obtained for the plate bending problem. This proof is based on the method of regularized Green's function and 'the trick of auxiliary element'.展开更多
Laser-assisted machining has been considered as a new alternative machining method of difficult-to-cut materials. A laser module with one-axis manipulator is developed to focus on preheating laser beam effectively. Fi...Laser-assisted machining has been considered as a new alternative machining method of difficult-to-cut materials. A laser module with one-axis manipulator is developed to focus on preheating laser beam effectively. First of all, the thermal characteristic analysis was performed to verify the importance of laser module location. Laser module should be moved within 1 mm. Analysis conditions of three positions in driving range of the one-axis manipulator are selected. And a C coupling is used as a connection device for spindle and laser module. An initial model has one C coupling, and the number of C coupling has been increased from 1 to 2 in an improved model. And the analysis is carried out again for the one-axis manipulator. The results of the static analysis, the maximum displacement and the maximum stress are decreased by 22% and 11%, respectively, for the improved model when the laser module is located at farthest away from the spindle unit. As a result of the modal analysis, the first natural frequency mode is increased by 13%, 18% and 12% at these positions of the improved model, respectively. The harmonic analysis of the improved model was performed by analyzing the results of the modal analysis. The maximum deformation was 0.33 mm in driving unit at 222 Hz. And the maximum compliance of the ISO axis direction was 0.23 mm/N. Finally, the one-axis manipulator has been fabricated successfully using the analysis result.展开更多
Objective: To evaluate the efficacy of adjuvant chemotherapy in patients with esophageal carcinoma undergoing radical surgery by meta-analysis. Methods: CBMDisc, CNKI, Pubmed databases were searched from January 1995 ...Objective: To evaluate the efficacy of adjuvant chemotherapy in patients with esophageal carcinoma undergoing radical surgery by meta-analysis. Methods: CBMDisc, CNKI, Pubmed databases were searched from January 1995 to June 2005. Randomized trials on comparison surgery plus adjuvant chemotherapy (S + C) and surgery alone for patients with local- ized carcinoma of esophagus were selected. RevMan 4.2 software was used for meta-analysis. Results: 7 studies were in- cluded in the meta-analysis. A total of 401 patients underwent radical surgery plus chemotherapy and 463 underwent surgery alone. Compared with surgery alone, the patients underwent S + C were significantly superior in the 3-year survival rate: the combined relative risk (RRs) of death was 0.83, 95% confidence interval (CI) was 0.71 to 0.95, P = 0.009. Conclusion: Based on the review, adjuvant chemotherapy has a benefit on the 3-year survival rate in the patients with esophageal carcinoma.展开更多
Pancreatic cancer ranks tenth in terms of newly diagnosed cases, but just 10%–15% of these patients can undergo resection. Survival after curative surgery is dismal, as recurrences occur either locally or in the live...Pancreatic cancer ranks tenth in terms of newly diagnosed cases, but just 10%–15% of these patients can undergo resection. Survival after curative surgery is dismal, as recurrences occur either locally or in the liver. Adjuvant treatment with either chemotherapy or chemoradiation (with or without maintenance chemotherapy) has been employed, to improve the poor prognosis. Justification for the use of chemoradiation, with follow on chemotherapy, is based on the results of an underpowered 1987 GITSG study, which closed prematurely and compared intervention to observation. There has been no survival advantage demonstrated in the one randomized controlled trial that examined chemoradiation compared to chemotherapy. There is a clear cut survival advantage however with chemotherapy compared to observation, based on the results from two large randomized controlled trials, and supported by an individual patient data meta-analysis. The standard of care for adjuvant therapy based on level I evidence (from the ESPAC-1 trial) is post operative chemotherapy using 5-Fluorouracil with folinic acid providing a best estimate of 29% five years survival.展开更多
In order to realize the computer aided design of AT shifting element schemes, a mathematical model of shifting element schemes which can be easily identified by computers was built. Taking the transmission ratio seque...In order to realize the computer aided design of AT shifting element schemes, a mathematical model of shifting element schemes which can be easily identified by computers was built. Taking the transmission ratio sequence as an optimization objective and simple shifting logic between adjacent gears through operating only one shifting element as a constraint condition, a fitness function of shifting element schemes was proposed. ZF-8AT shifting element schemes were optimized based on GA work-box of MATLAB, and the feasibility of the optimization algorithm was verified.展开更多
Essence of education is to guide. The scene teachers create is like a key to help the students feel the music, and played an active role in the teaching process immeasurably. Through multimedia assisted teaching, the ...Essence of education is to guide. The scene teachers create is like a key to help the students feel the music, and played an active role in the teaching process immeasurably. Through multimedia assisted teaching, the use of a wide range of teaching methods in music teaching, so that the children take the initiative to actively participate in musical activities to develop their musical aesthetic and correct music ability to inspire their interest in learning music, promote classroom further improve the quality of teaching.展开更多
Copper is a trace element that is required by almost all forms of life.Acting as cofactors for various key metabolism enzymes,copper takes part in many vital biological processes.Previous studies have found the concen...Copper is a trace element that is required by almost all forms of life.Acting as cofactors for various key metabolism enzymes,copper takes part in many vital biological processes.Previous studies have found the concentration of copper is significantly higher in tumor cells than in normal cells.In addition,copper can promote angiogenesis by activating VEGF and FGF signaling.展开更多
A stress analysis of the Sarafix external fixator design was performed using finite element analysis （FEA） and experimental tensometric measurements. The study was conducted at one of the Sarafix fixator configurati...A stress analysis of the Sarafix external fixator design was performed using finite element analysis （FEA） and experimental tensometric measurements. The study was conducted at one of the Sarafix fixator configurations that have a clinical application in the treatment of tibia fractures. The intensity of principal and yon Mises stresses generated at two measuring points （MP） on the fixator connecting rod were monitored and analyzed during the testing on axial compression on the fixator design and its finite element model （FEM）. The 3D geometrical and FEM model of the fixator was formed using the computer aided design/computer aided engineering （CAD/CAE） software system CATIA. Verification of the results for the dominant principal stresses obtained from FEA was carried out through tensometric measurements. The measuring chain consisted of strain gauges connected into two Wheatstone half-bridges, digital measuring amplifier system and a computer with software for acquisition and monitoring of measurement results. A quite good agreement was observed between the results obtained on the basis of FEA and results of experimental tensometric analysis,展开更多
An accurate assessment of the property value is very important to make a deal, property tax, and mortgage for loan. The mass appraisal system has been developed in some foreign countries, especially in American for a ...An accurate assessment of the property value is very important to make a deal, property tax, and mortgage for loan. The mass appraisal system has been developed in some foreign countries, especially in American for a long time. In Taiwan, we still have few experiences in using computer-assisted mass appraisal system, especially using artificial neural network （ANN）. This article has two objectives： （1） to illustrate application of ANN to the Kaohsiung property market by the method of back-propagation. The study is based on the properties data of sales price, we also use multiple regressions in the same data; （2） to evaluate the performance of two models by using the mean absolute percentage error （MAPE） and hit ratio （HR）. This paper finds that using artificial neural network （ANN） is able to overcome multiple regressions＇ methodological problems and also get better performance than multiple regression model （MRA）. These results are useful in helping local government to assess their assessment value.展开更多
Brazing has a wide acceptance in industries and its simplicity in variety of application attracts more and more patronage. The strength of brazing joint determines the reliability of brazed engineering components. So ...Brazing has a wide acceptance in industries and its simplicity in variety of application attracts more and more patronage. The strength of brazing joint determines the reliability of brazed engineering components. So the need to ascertain the reliability or to predict its failure （without some destructive testing） becomes high even with a computer aided analysis using the Finite Element Analysis. Here, we have employed the services of FEA software, Abaqus CAE, as a tool for the computer calculation to investigate a joint case of cemented carbide brazed with silver-based filler metal. In this paper, 2D analysis has been adopted because the thickness of the material （in 2D） does not influence the final calculation results. We have applied constant loading and constant boundary condition to explore data from the elastic and plastic strain analysis through which we were able to predict the maximum joint strength with respect to the joint thickness. The pattern of the meshing was also significant. And the result could be transferable to a real-life field situation. The final results showed that there is an optimum thickness of the filler metal with the maximum strength which matches that obtained from experiment.展开更多
文摘To estimate the geometric characteristics, especially wet areas and section areas, of three dimensional numerical conceptual aircraft models, a method based on surface elements is proposed. On the premise that numerous surface elements are generated to represent each component surface, a component wet area of the surface is estimated by adding up the areas of such elements that are not covered by any other component surfaces. The elements are also used to get the section polygons of such composite surfaces as the whole aircraft at a given body station, then a section area is approximated with the sum of trapezoidal areas between such sides of polygons that are not covered by any other component and a reference axis. Practical application to a computer aided aircraft conceptual design system shows that the methed is applicable to different kinds of conceptual aircraft models and its precision is satisfying to the conceptual design.
基金Project(51275475)supported by the National Natural Science Foundation of ChinaProject(2014BY001)supported by the Department of Education in Zhejiang Province,ChinaProject(2014EP0110)supported by the Key Laboratory of Special Purpose Equipment and Advanced Manufacturing Technology,Ministry of Education and Zhejiang Province,China
文摘The possibility of the electric-hydraulic chattering technology and its application in the cold extrusion were presented.The conventional and electric-hydraulic chattering assisted backward extrusion processes were performed on 6061 aluminum alloy billets at room temperature.The experimental results showed that 5.65% reduction in the extrusion load was attained if the die and ejector were vibrated at a frequency of 100 Hz and amplitude of 0.013 mm in the longitudinal direction.The friction coefficient at the billet and tool system interface determined from the finite element analysis（FEA） decreased from 0.2 without chattering to 0.1 with application of electric-hydraulic chattering.The higher values of instantaneous velocity and direction change of material flow were achieved during the chattering assisted backward extrusion process.The strain distribution of the chattering assisted backward extrusion billet revealed lower maximum strain and smoother strain distribution in comparison with that produced by the conventional extrusion method.
文摘In this paper,a nonconforming rectangular plate element,the modified incomplete biquadratic plate element,is considered. The asympotic optimal L~∞-error estimate is obtained for the plate bending problem. This proof is based on the method of regularized Green's function and 'the trick of auxiliary element'.
基金Project(2012-0005688) supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea Government (MEST)
文摘Laser-assisted machining has been considered as a new alternative machining method of difficult-to-cut materials. A laser module with one-axis manipulator is developed to focus on preheating laser beam effectively. First of all, the thermal characteristic analysis was performed to verify the importance of laser module location. Laser module should be moved within 1 mm. Analysis conditions of three positions in driving range of the one-axis manipulator are selected. And a C coupling is used as a connection device for spindle and laser module. An initial model has one C coupling, and the number of C coupling has been increased from 1 to 2 in an improved model. And the analysis is carried out again for the one-axis manipulator. The results of the static analysis, the maximum displacement and the maximum stress are decreased by 22% and 11%, respectively, for the improved model when the laser module is located at farthest away from the spindle unit. As a result of the modal analysis, the first natural frequency mode is increased by 13%, 18% and 12% at these positions of the improved model, respectively. The harmonic analysis of the improved model was performed by analyzing the results of the modal analysis. The maximum deformation was 0.33 mm in driving unit at 222 Hz. And the maximum compliance of the ISO axis direction was 0.23 mm/N. Finally, the one-axis manipulator has been fabricated successfully using the analysis result.
文摘Objective: To evaluate the efficacy of adjuvant chemotherapy in patients with esophageal carcinoma undergoing radical surgery by meta-analysis. Methods: CBMDisc, CNKI, Pubmed databases were searched from January 1995 to June 2005. Randomized trials on comparison surgery plus adjuvant chemotherapy (S + C) and surgery alone for patients with local- ized carcinoma of esophagus were selected. RevMan 4.2 software was used for meta-analysis. Results: 7 studies were in- cluded in the meta-analysis. A total of 401 patients underwent radical surgery plus chemotherapy and 463 underwent surgery alone. Compared with surgery alone, the patients underwent S + C were significantly superior in the 3-year survival rate: the combined relative risk (RRs) of death was 0.83, 95% confidence interval (CI) was 0.71 to 0.95, P = 0.009. Conclusion: Based on the review, adjuvant chemotherapy has a benefit on the 3-year survival rate in the patients with esophageal carcinoma.
文摘Pancreatic cancer ranks tenth in terms of newly diagnosed cases, but just 10%–15% of these patients can undergo resection. Survival after curative surgery is dismal, as recurrences occur either locally or in the liver. Adjuvant treatment with either chemotherapy or chemoradiation (with or without maintenance chemotherapy) has been employed, to improve the poor prognosis. Justification for the use of chemoradiation, with follow on chemotherapy, is based on the results of an underpowered 1987 GITSG study, which closed prematurely and compared intervention to observation. There has been no survival advantage demonstrated in the one randomized controlled trial that examined chemoradiation compared to chemotherapy. There is a clear cut survival advantage however with chemotherapy compared to observation, based on the results from two large randomized controlled trials, and supported by an individual patient data meta-analysis. The standard of care for adjuvant therapy based on level I evidence (from the ESPAC-1 trial) is post operative chemotherapy using 5-Fluorouracil with folinic acid providing a best estimate of 29% five years survival.
基金Project(2011BAG09B00)supported by the National Science and Technology Support Program,China
文摘In order to realize the computer aided design of AT shifting element schemes, a mathematical model of shifting element schemes which can be easily identified by computers was built. Taking the transmission ratio sequence as an optimization objective and simple shifting logic between adjacent gears through operating only one shifting element as a constraint condition, a fitness function of shifting element schemes was proposed. ZF-8AT shifting element schemes were optimized based on GA work-box of MATLAB, and the feasibility of the optimization algorithm was verified.
文摘Essence of education is to guide. The scene teachers create is like a key to help the students feel the music, and played an active role in the teaching process immeasurably. Through multimedia assisted teaching, the use of a wide range of teaching methods in music teaching, so that the children take the initiative to actively participate in musical activities to develop their musical aesthetic and correct music ability to inspire their interest in learning music, promote classroom further improve the quality of teaching.
文摘Copper is a trace element that is required by almost all forms of life.Acting as cofactors for various key metabolism enzymes,copper takes part in many vital biological processes.Previous studies have found the concentration of copper is significantly higher in tumor cells than in normal cells.In addition,copper can promote angiogenesis by activating VEGF and FGF signaling.
文摘A stress analysis of the Sarafix external fixator design was performed using finite element analysis （FEA） and experimental tensometric measurements. The study was conducted at one of the Sarafix fixator configurations that have a clinical application in the treatment of tibia fractures. The intensity of principal and yon Mises stresses generated at two measuring points （MP） on the fixator connecting rod were monitored and analyzed during the testing on axial compression on the fixator design and its finite element model （FEM）. The 3D geometrical and FEM model of the fixator was formed using the computer aided design/computer aided engineering （CAD/CAE） software system CATIA. Verification of the results for the dominant principal stresses obtained from FEA was carried out through tensometric measurements. The measuring chain consisted of strain gauges connected into two Wheatstone half-bridges, digital measuring amplifier system and a computer with software for acquisition and monitoring of measurement results. A quite good agreement was observed between the results obtained on the basis of FEA and results of experimental tensometric analysis,
文摘An accurate assessment of the property value is very important to make a deal, property tax, and mortgage for loan. The mass appraisal system has been developed in some foreign countries, especially in American for a long time. In Taiwan, we still have few experiences in using computer-assisted mass appraisal system, especially using artificial neural network （ANN）. This article has two objectives： （1） to illustrate application of ANN to the Kaohsiung property market by the method of back-propagation. The study is based on the properties data of sales price, we also use multiple regressions in the same data; （2） to evaluate the performance of two models by using the mean absolute percentage error （MAPE） and hit ratio （HR）. This paper finds that using artificial neural network （ANN） is able to overcome multiple regressions＇ methodological problems and also get better performance than multiple regression model （MRA）. These results are useful in helping local government to assess their assessment value.
文摘Brazing has a wide acceptance in industries and its simplicity in variety of application attracts more and more patronage. The strength of brazing joint determines the reliability of brazed engineering components. So the need to ascertain the reliability or to predict its failure （without some destructive testing） becomes high even with a computer aided analysis using the Finite Element Analysis. Here, we have employed the services of FEA software, Abaqus CAE, as a tool for the computer calculation to investigate a joint case of cemented carbide brazed with silver-based filler metal. In this paper, 2D analysis has been adopted because the thickness of the material （in 2D） does not influence the final calculation results. We have applied constant loading and constant boundary condition to explore data from the elastic and plastic strain analysis through which we were able to predict the maximum joint strength with respect to the joint thickness. The pattern of the meshing was also significant. And the result could be transferable to a real-life field situation. The final results showed that there is an optimum thickness of the filler metal with the maximum strength which matches that obtained from experiment.
