Objective： The aim of this work was to quantify the extent of set-up errors to conduct a quality assurance （QA） aspect of treatment delivery, verification of the treatment field＇s position on different days using ...Objective： The aim of this work was to quantify the extent of set-up errors to conduct a quality assurance （QA） aspect of treatment delivery, verification of the treatment field＇s position on different days using electronic portal. Methods： This study was carried out on 12 patients, treated for pelvis tumor; and total of 240 images obtained by electronic portal image device （EPID） were analyzed. The EPIs acquire using EPID attached to the Siemens linear accelerator. The anatomy match- ing software （Theraview） was used and displacement in two dimensions were noted for each treatment field to study patient setup errors. Results： The percentages of mean deviations less than 5 mm in X direction were 65% ＆ 92%, from 5-10 mm were 31% ＆ 19% and more than 10 mm were 11% ＆ 9% forNP and lateral direction respectively. The percentages of mean deviations less than 5 mm in Y direction were 65% ＆ 63%, from 5-10 mm were 33% ＆ 28% and more than 10 mm were 22% ＆ 29%. The mean deviations in 2D-vector errors were 〈 5 mm in 47% and 46%, 5-10 mm in 36% and 37% and 〉 10 mm in 37% and 37% of images in the NP and lateral direction respectively. Conclusion： The results revealed that the ranges of set up errors are immobilization method to improve reproducibility. The observed variations were not within the limits..展开更多
A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of whee...A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of wheel structural unit,suspension unit,and connecting device unit between suspension and load platform,some new locomotion system configurations were proposed and the metrics and indexes to evaluate the performance of the new locomotion system were analyzed.Performance evaluation and comparison between two LER with locomotion systems of different configurations were analyzed.The analysis results indicate that the new locomotion system configuration has good trafficability performance.展开更多
Multidimensional Scale Evaluation Rules as a performer in the field of learning assessment is feasible, but for each dimension settings, level settings and value setting need to be developed according to the actual ra...Multidimensional Scale Evaluation Rules as a performer in the field of learning assessment is feasible, but for each dimension settings, level settings and value setting need to be developed according to the actual raters, object evaluation, the focus of the evaluation. Scores of overall dimensions use variance analysis, and the results show a significant difference. In sub-dimension score comparison, the high group and low group both got higher scores in the degree of difficulty performing works and read music accuracy. The high group and low group are different on dimensions of the lowest score. Total scores in the scale of multi-dimensional evaluation of rules are positively correlated on the scores on the improvising horizontal dimension, but the correlation is not very high level, that is not all students who is better in playing levels, and they can get higher scores on the improvising horizontal dimension. Using multi-dimensional scale scores and teacher direct evaluation rules score are significantly different for student achievement.展开更多
To aim at design requirements of high lift-to-drag ratio as well as high volumetric efficiency of next generation hypersonic airplanes,a body-wing-blending configuration with double flanking air inlets layout is prese...To aim at design requirements of high lift-to-drag ratio as well as high volumetric efficiency of next generation hypersonic airplanes,a body-wing-blending configuration with double flanking air inlets layout is presented.Moreover,a novel forebody design methodology which by rotating and assembling two waverider-based surfaces is firstly introduced in this paper.Some typical configurations are designed and their aerodynamic performances are evaluated by computational fluid dynamics.The results for forebodies analysis show that large volumetric efficiency,high lift-to-drag ratio,and uniformly distributed flowfield at the inlet cross section can be assured simultaneously.Furthermore,results of numerical simulation of four integrated configurations with various leading edge shapes,including three power-law curves and a cosine curve clearly show the advantage of high lift-to-drag ratio.Besides,the high pressure generated by the side wall of the airframe can be partly captured by the reasonably designed wings in the condition of small flight attack angle.Then the order of lift-to-drag ratio of four configurations at 0 degree flight attack angle is completely different from the condition of 4-degree flight attack angle.This result demonstrates that the curve shape of the leading edge is very important for the lift-to-drag ratio of the aircraft,and it should be further optimized under the cruising attack angle in future work.展开更多
文摘Objective： The aim of this work was to quantify the extent of set-up errors to conduct a quality assurance （QA） aspect of treatment delivery, verification of the treatment field＇s position on different days using electronic portal. Methods： This study was carried out on 12 patients, treated for pelvis tumor; and total of 240 images obtained by electronic portal image device （EPID） were analyzed. The EPIs acquire using EPID attached to the Siemens linear accelerator. The anatomy match- ing software （Theraview） was used and displacement in two dimensions were noted for each treatment field to study patient setup errors. Results： The percentages of mean deviations less than 5 mm in X direction were 65% ＆ 92%, from 5-10 mm were 31% ＆ 19% and more than 10 mm were 11% ＆ 9% forNP and lateral direction respectively. The percentages of mean deviations less than 5 mm in Y direction were 65% ＆ 63%, from 5-10 mm were 33% ＆ 28% and more than 10 mm were 22% ＆ 29%. The mean deviations in 2D-vector errors were 〈 5 mm in 47% and 46%, 5-10 mm in 36% and 37% and 〉 10 mm in 37% and 37% of images in the NP and lateral direction respectively. Conclusion： The results revealed that the ranges of set up errors are immobilization method to improve reproducibility. The observed variations were not within the limits..
基金Supported by National "863" High-Tech Program (No.2006AA04Z231)Foundation of State Key Laboratory of Robotics and Systems (No.SKLRS-200801A02)+1 种基金the College Discipline Innovation Wisdom Plan (No.B07018)Natural Science Foundation of Heilongjiang Province (No.ZJG0709)
文摘A method of topology synthesis based on graph theory and mechanism combination theory was applied to the configuration design of locomotion systems of lunar exploration rovers(LER).Through topology combination of wheel structural unit,suspension unit,and connecting device unit between suspension and load platform,some new locomotion system configurations were proposed and the metrics and indexes to evaluate the performance of the new locomotion system were analyzed.Performance evaluation and comparison between two LER with locomotion systems of different configurations were analyzed.The analysis results indicate that the new locomotion system configuration has good trafficability performance.
文摘Multidimensional Scale Evaluation Rules as a performer in the field of learning assessment is feasible, but for each dimension settings, level settings and value setting need to be developed according to the actual raters, object evaluation, the focus of the evaluation. Scores of overall dimensions use variance analysis, and the results show a significant difference. In sub-dimension score comparison, the high group and low group both got higher scores in the degree of difficulty performing works and read music accuracy. The high group and low group are different on dimensions of the lowest score. Total scores in the scale of multi-dimensional evaluation of rules are positively correlated on the scores on the improvising horizontal dimension, but the correlation is not very high level, that is not all students who is better in playing levels, and they can get higher scores on the improvising horizontal dimension. Using multi-dimensional scale scores and teacher direct evaluation rules score are significantly different for student achievement.
基金supported by the National Natural Science Foundation of China (Grant No. 90916013)the guidance and help from Academician Li Tian and peer reviewers are gratefully acknowledged
文摘To aim at design requirements of high lift-to-drag ratio as well as high volumetric efficiency of next generation hypersonic airplanes,a body-wing-blending configuration with double flanking air inlets layout is presented.Moreover,a novel forebody design methodology which by rotating and assembling two waverider-based surfaces is firstly introduced in this paper.Some typical configurations are designed and their aerodynamic performances are evaluated by computational fluid dynamics.The results for forebodies analysis show that large volumetric efficiency,high lift-to-drag ratio,and uniformly distributed flowfield at the inlet cross section can be assured simultaneously.Furthermore,results of numerical simulation of four integrated configurations with various leading edge shapes,including three power-law curves and a cosine curve clearly show the advantage of high lift-to-drag ratio.Besides,the high pressure generated by the side wall of the airframe can be partly captured by the reasonably designed wings in the condition of small flight attack angle.Then the order of lift-to-drag ratio of four configurations at 0 degree flight attack angle is completely different from the condition of 4-degree flight attack angle.This result demonstrates that the curve shape of the leading edge is very important for the lift-to-drag ratio of the aircraft,and it should be further optimized under the cruising attack angle in future work.
