目的评价锥形束CT对牙槽骨线距测量的准确性与可靠性。方法通过检索多个数据库（PubMed，EBSCO，Scopus，Web of Science，中国期刊全文专题数据库CNKI及中国科技期刊数据库）获得相关文献。设定纳入标准为对人类牙槽骨的测量，并评价...目的评价锥形束CT对牙槽骨线距测量的准确性与可靠性。方法通过检索多个数据库（PubMed，EBSCO，Scopus，Web of Science，中国期刊全文专题数据库CNKI及中国科技期刊数据库）获得相关文献。设定纳入标准为对人类牙槽骨的测量，并评价其测量的准确性和／或可靠性，对检索获得的文献进行进一步筛选。利用方法学评价表对纳入的文献进行评价。结果检索获得150篇文献，通过筛选共12篇文献纳入本系统综述。其中有8篇文章关注对牙槽骨厚度及／或高度的测量，4篇文章关注对牙槽骨缺损的测量。利用方法学评价表进行评价，仅有3篇文章的方法学质量较高，6篇文章方法学质量较低。锥形束CT对牙槽骨线距测量的准确性与可靠性较好，但应注意其有低估牙槽骨高度及厚度的趋势。CBCT测量与传统二维影像学检查的准确性有一定差异，当只有二维影像检查资料时，CBCT图像数据不宜纳入纵向比较。结论锥形束CT对牙槽骨线距测量的准确性与可靠性较好。展开更多
The spatial structure of the velocity field in a stirred vessel with water has been measured and analyzed using the laser Doppler velocimeter technique, with the immersing depth and agitation speed of the impeller re-...The spatial structure of the velocity field in a stirred vessel with water has been measured and analyzed using the laser Doppler velocimeter technique, with the immersing depth and agitation speed of the impeller re-maining approximately constant. The experimental results were provided such as the mean velocity field, fluctuat-ing velocities, turbulent kinetic energy, Reynolds shear stress and time series of the velocity in the stirred tank. These results probably provided the valuable basis to further optimize and enlarge the stirred tank in the industrial process.展开更多
This paper presents a lumped mass model to describe the run-out and velocity of a series of large flume tests,which was carried out to investigate some propagation mechanisms involved in rapid,dry,dense granular flows...This paper presents a lumped mass model to describe the run-out and velocity of a series of large flume tests,which was carried out to investigate some propagation mechanisms involved in rapid,dry,dense granular flows and energy transformation when the flows encountered obstacles and reoriented their movement directions.Comparisons between predicted and measured results show that the trend of predicted velocities was basically matched with that of measured ones.Careful scrutiny of test videos reveals that subsequent particles with a higher velocity collided with slowed fronts to make them accelerate. However,this simple model cannot reflect collisions between particles because it treated released materials as a rigid block.Thus,the predicted velocity was somewhat lower than the measured velocity in most cases.When the flow changed its direction due to the variation in slope inclination,the model predicted a decrease in velocity.The predicted decrease in velocity was less than the measured one within a reasonable range of 10% or less.For some cases in which a convexity was introduced,the model also predicted the same trend of velocities as measured in the tests.The velocity increased greatly after the materials took a ballistic trajectory from the vertex of the convexity,and reduced dramatically when they finally made contact with the base of the lower slope.The difference between prediced and measured decrease in velocity was estimated to be about 5% due to the landing.Therefore,the simple lumped mass model based on the energy approach could roughly predict the run-out and velocity of granular flows,although it neglected internal deformation,intergranular collision and friction.展开更多
文摘目的评价锥形束CT对牙槽骨线距测量的准确性与可靠性。方法通过检索多个数据库（PubMed，EBSCO，Scopus，Web of Science，中国期刊全文专题数据库CNKI及中国科技期刊数据库）获得相关文献。设定纳入标准为对人类牙槽骨的测量，并评价其测量的准确性和／或可靠性，对检索获得的文献进行进一步筛选。利用方法学评价表对纳入的文献进行评价。结果检索获得150篇文献，通过筛选共12篇文献纳入本系统综述。其中有8篇文章关注对牙槽骨厚度及／或高度的测量，4篇文章关注对牙槽骨缺损的测量。利用方法学评价表进行评价，仅有3篇文章的方法学质量较高，6篇文章方法学质量较低。锥形束CT对牙槽骨线距测量的准确性与可靠性较好，但应注意其有低估牙槽骨高度及厚度的趋势。CBCT测量与传统二维影像学检查的准确性有一定差异，当只有二维影像检查资料时，CBCT图像数据不宜纳入纵向比较。结论锥形束CT对牙槽骨线距测量的准确性与可靠性较好。
基金Supported by the Natural Science Foundation of Inner Mongolia (No.200408020715).
文摘The spatial structure of the velocity field in a stirred vessel with water has been measured and analyzed using the laser Doppler velocimeter technique, with the immersing depth and agitation speed of the impeller re-maining approximately constant. The experimental results were provided such as the mean velocity field, fluctuat-ing velocities, turbulent kinetic energy, Reynolds shear stress and time series of the velocity in the stirred tank. These results probably provided the valuable basis to further optimize and enlarge the stirred tank in the industrial process.
基金supported by theopen fund project of Scientific Alleviation of Disasters and Home Rebuilding(Grant No.DZJK-0814)from the Chinese State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology
文摘This paper presents a lumped mass model to describe the run-out and velocity of a series of large flume tests,which was carried out to investigate some propagation mechanisms involved in rapid,dry,dense granular flows and energy transformation when the flows encountered obstacles and reoriented their movement directions.Comparisons between predicted and measured results show that the trend of predicted velocities was basically matched with that of measured ones.Careful scrutiny of test videos reveals that subsequent particles with a higher velocity collided with slowed fronts to make them accelerate. However,this simple model cannot reflect collisions between particles because it treated released materials as a rigid block.Thus,the predicted velocity was somewhat lower than the measured velocity in most cases.When the flow changed its direction due to the variation in slope inclination,the model predicted a decrease in velocity.The predicted decrease in velocity was less than the measured one within a reasonable range of 10% or less.For some cases in which a convexity was introduced,the model also predicted the same trend of velocities as measured in the tests.The velocity increased greatly after the materials took a ballistic trajectory from the vertex of the convexity,and reduced dramatically when they finally made contact with the base of the lower slope.The difference between prediced and measured decrease in velocity was estimated to be about 5% due to the landing.Therefore,the simple lumped mass model based on the energy approach could roughly predict the run-out and velocity of granular flows,although it neglected internal deformation,intergranular collision and friction.
