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低温强化处理对口腔修复中高熔铸造合金三维量度的影响 被引量:10
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作者 朱智敏 蒋晓旭 毛祥彦 《华西口腔医学杂志》 CAS CSCD 北大核心 1997年第3期251-253,共3页
考察了在低温强化处理过程中不同的降温速率对口腔修复常用铸造合金三维量度的影响,旨在了解此方法应用于口腔修复的可行性,并为选择适用于中、高熔铸造合金的处理曲线提供依据。结果表明:1.快速降温法引起的合金变形量最为显著;... 考察了在低温强化处理过程中不同的降温速率对口腔修复常用铸造合金三维量度的影响,旨在了解此方法应用于口腔修复的可行性,并为选择适用于中、高熔铸造合金的处理曲线提供依据。结果表明:1.快速降温法引起的合金变形量最为显著;2.3℃/min和1℃/min的降温速率均不会引起合金尺寸的显著性变化;3.3℃/min和1℃/min的降温速率所引起的合金微小变形量间无显著性差异;4.快速降温法和缓慢降温法(3℃/min和1℃/min)所产生的合金变形量间有显著性差异。提示:在适当的降温速率下,低温强化处理不会引起合金的明显变形。3℃/min的降温速率适用于处理中高熔铸造合金。 展开更多
关键词 低温强化处理 铸造合金 三维量度
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卫生法学课堂教学质量的三维量度
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作者 于情 李黎 《牡丹江医学院学报》 2010年第6期77-78,共2页
每门课程的课堂教学都在整个教学体系中占有主导地位,课堂教学质量的高低,直接影响课程教学目标的最终实现。因此,进行课堂教学质量的全面管理是实现课堂教学科学有效、提高教学质量、实现教学目的的重要手段。
关键词 课堂教学质量 三维量度 卫生法学 课程教学目标 教学体系 教学目的
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Quantum Secure Direct Communication by Using Three-Dimensional Hyperentanglement 被引量:8
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作者 施锦 龚彦晓 +2 位作者 徐平 祝世宁 詹佑邦 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第11期831-836,共6页
We propose two schemes for realizing quantum secure direct communication (QSDC)by using a set ofordered two-photon three-dimensional hyperentangled states entangled in two degrees of freedom (DOFs)as quantuminformatio... We propose two schemes for realizing quantum secure direct communication (QSDC)by using a set ofordered two-photon three-dimensional hyperentangled states entangled in two degrees of freedom (DOFs)as quantuminformation channels.In the first scheme,the photons from Bob to Alice are transmitted only once.After insuring thesecurity of the quantum channels,Bob encodes the secret message on his photons.Then Alice performs single-photontwo-DOF Bell bases measurements on her photons.This scheme has better security than former QSDC protocols.In thesecond scheme,Bob transmits photons to Alice twice.After insuring the security of the quantum channels,Bob encodesthe secret message on his photons.Then Alice performs two-photon Bell bases measurements on each DOF.The schemehas more information capacity than former QSDC protocols. 展开更多
关键词 quantum secure direct communication hyperentanglement Bell bases measurement
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Automated Phase-measuring Profilometry of 3-D Diffuse Objects Using a Single Phase Step Method 被引量:2
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作者 ZHAO Hong,SONG Yuanhe,CHEN Wenyi,TAN Yushan (Research Institute for Laser & Infrared Application, Xi’an Jiaotong University,Xi’an 710049,CHN) 《Semiconductor Photonics and Technology》 CAS 1998年第1期25-30,35,共7页
The technique of phase measuring profilometry using a single phase step method is proposed.This method can automatically obtain phase value at each pixel by using a discret cosine transform algorithm.The method is abl... The technique of phase measuring profilometry using a single phase step method is proposed.This method can automatically obtain phase value at each pixel by using a discret cosine transform algorithm.The method is able to automatically recognize any position between depression and elevation on an object surface.Theoretical analysis and experimental verification are presented. 展开更多
关键词 Discret Cosine Transform Noncontact Optical Measurement One Step Phase-shifting Phase-measuring 3-D Profilometry
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THREE-DIMENSIONAL VARIABLES ALLOCATION IN MESOSCALE MODELS
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作者 刘宇迪 陆汉城 《Journal of Tropical Meteorology》 SCIE 2004年第2期123-132,共10页
Forecasts and simulations are varied owing to different allocation of 3-dimensional variables in mesoscale models. No attempts have been made to address the issue of optimizing the simulation with a 3-dimensional vari... Forecasts and simulations are varied owing to different allocation of 3-dimensional variables in mesoscale models. No attempts have been made to address the issue of optimizing the simulation with a 3-dimensional variables distribution that should come to be. On the basis of linear nonhydrostatic anelastic equations, the paper hereby compares, mainly graphically, the computational dispersion with analytical solutions for four kinds of 3-dimensional meshes commonly found in mesoscale models, in terms of frequency, horizontal and vertical group velocities. The result indicates that the 3-D mesh C/CP has the best computational dispersion, followed by Z/LZ and Z/LY, with the C/L having the worst performance. It is then known that the C/CP mesh is the most desirable allocation in the design of nonhydrostatic baroclinic models. The mesh has, however, larger errors when dealing with shorter horizontal wavelengths. For the simulation of smaller horizontal scales, the horizontal grid intervals have to be shortened to reduce the errors. Additionally, in view of the dominant use of C/CP mesh in finite-difference models, it should be used in conjunction with the Z/LZ or Z/LY mesh if variables are allocated in spectral models. 展开更多
关键词 D variable allocation mesoscale models FREQUENCY group velocity NONHYDROSTATIC anelastic
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Analysis on accuracy of Engineering Star RTK in cadastral survey based on SOUTH-CORS
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作者 SONG Yuanming LIU Lilong HU Jiaxing LIU Jingye 《Global Geology》 2010年第3期135-140,共6页
Currently,with the fast development of GPS technique,GPS RTK is rapidly being applied to the cadastral survey. GPS RTK technique not only improves efficiency and accelerates the rate of mapping,but also increases econ... Currently,with the fast development of GPS technique,GPS RTK is rapidly being applied to the cadastral survey. GPS RTK technique not only improves efficiency and accelerates the rate of mapping,but also increases economic efficiency. The authors introduced a method for GPS RTK rapid positioning,which uses continuous operational reference system (CORS) as a base station to change the method of previous map drawing by obtaining real-time three-dimensional coordinates of boundary points and statistically analyzing with the three-dimensional coordinates obtained by Total Station to get the accuracy of GPS RTK real-time coordinates. The application of GPS RTK in practical measurement was discussed when the data link had been lost especially. The results show that the three-dimensional coordinates measured by total station can be replaced by real-time three-dimensional coordinates measured by Engineering Star RTK in the CORS. 展开更多
关键词 continuous operational reference system data processing statistical analysis OFFSET data link
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Investigations of 3D Surface Roughness Characteristic's Accuracy
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作者 Maris Kumermanis Janis Rudzitis Anita Avisane 《Journal of Mechanics Engineering and Automation》 2013年第10期632-640,共9页
The existing surface roughness standards comprise only two dimensions. However, the real roughness of the surface is 3D (three-dimensional). Roughness parameters of the 3D surface are also important in analyzing the... The existing surface roughness standards comprise only two dimensions. However, the real roughness of the surface is 3D (three-dimensional). Roughness parameters of the 3D surface are also important in analyzing the mechanics of contact surfaces. Problems of mechanics of contact surfaces are related to accuracy of 3D surface roughness characteristic. One of the most important factors for 3D characteristics determination is the number of data points per x and y axes. With number of data points we understand its number in cut-off length. Number of data points have substantial influence on the accuracy of measurement results, measuring time and size of output data file (especially along the y-axis direction, where number of data points are number of parallel profiles). Number of data points must be optimal. Small number of data points lead to incorrect results and increase distribution amplitude, but too large number of data points do not enlarge range of fundamental information, but substantially increase measuring time. Therefore, we must find optimal number of data points per each surface processing method. 展开更多
关键词 Surface topography roughness assessment accuracy measurement instruction.
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Latitudinal and climatic distributions of 3D craniofacial features among Holocene populations 被引量:1
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作者 PAN Lei WEI Dong WU XiuJie1? 《Science China Earth Sciences》 SCIE EI CAS 2014年第7期1692-1700,共9页
The geographical and climatic patterning in craniofacial morphology among recent hominids has been regarded as relatively reliable evidence of environmental adaptation and natural selection,which is largely attributed... The geographical and climatic patterning in craniofacial morphology among recent hominids has been regarded as relatively reliable evidence of environmental adaptation and natural selection,which is largely attributed to thermoregulation.However,the relative influence of genetic and environmental factors on craniofacial features is unclear.Our study employed 3D laser scanning techniques to evaluate the association between geographical(latitude),climatic(annual temperature)factors,and 3D craniofacial measurements in 18 recent populations through bivariate correlation analysis.Significant correlations were found among braincase surface area,zygomatic bone surface area,cranial-facial index(facial surface area relative to braincase surface area)and local temperature,and a clear latitudinal gradient was also found in variation of braincase surface area.No significant correlations were found between zygomatic bone surface area,cranial-facial index and latitude.Our analysis supports the idea that the braincase functions as a radiator and is closely related to direct sunlight.We also suggest that absolute/relative craniofacial surface area varies consistently with predictions derived from Bergmann’s Rule.The mosaic craniofacial traits of American Indians may reflect retention of cold-derived,ancestral features,as well as a response to a slightly warmer climate.Because different craniofacial regions preserve environmental/genetic signatures differentially,caution is suggested when craniofacial anatomy is used for phylogenetic reconstruction and functional-morphological analysis. 展开更多
关键词 Holocene population craniofacial morphology surface area LATITUDE temperature
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Study on Blade Surface Flow around Wind Turbine by Using LDV Measurements 被引量:4
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作者 Tinnapob Phengpom Yasunari Kamada +3 位作者 Takao Maeda Junsuke Murata Shogo Nishimura Tasuku Matsuno 《Journal of Thermal Science》 SCIE EI CAS CSCD 2015年第2期131-139,共9页
This paper has attempted to study a mechanism of three-dimensional flow around a horizontal axis wind turbine(HAWT) rotor blade. An experimental study of the flow phenomenon in the vicinity of the wind turbine blade i... This paper has attempted to study a mechanism of three-dimensional flow around a horizontal axis wind turbine(HAWT) rotor blade. An experimental study of the flow phenomenon in the vicinity of the wind turbine blade is a challenging endeavor. In this research, the HAWT model with 2.4 m diameter was tested in the large wind tunnel. The flow around the rotating blade surface was measured simultaneously for three velocity components, and two probes were used for the synchronized measurement of three-dimensional flow components. The local velocity was detected for the single seeding particle measured in the point where three pairs of laser beams intersected. Blade sections of interest in this study are composed of radial positions r/R = 0.3, 0.5 and 0.7. Optimum and low tip speed ratio flow characteristics were also compared. The velocity flow vector, skin friction coefficient and bound circulation were calculated from LDV measurements, and the experimental research showed reasonably and clearly the experimental results. 展开更多
关键词 LDV measurement Sectional performance Wind turbine Boundary layer flow Span-wise flow
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Flow Instability of a Centrifugal Pump Determined Using the Energy Gradient Method 被引量:5
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作者 Li Yi Dong Wenlong +2 位作者 He Zhaohui Huang Yuanmin Jiang Xiaojun 《Journal of Thermal Science》 SCIE EI CAS CSCD 2015年第1期44-48,共5页
The stability of the centrifugal pump has not been well revealed because of the complexity of internal flow. To analyze the flow characteristics of a centrifugal pump operating at low capacity, methods of numerical si... The stability of the centrifugal pump has not been well revealed because of the complexity of internal flow. To analyze the flow characteristics of a centrifugal pump operating at low capacity, methods of numerical simulation and experimental research were adopted in this paper. Characteristics of the inner flow were obtained. Standard k-s turbulence models were used to calculate the inner flow of the pump under off-design conditions. The distri- bution of the energy gradient function K was obtained by three-dimensional numerical simulation at different flow rates. The relative velocity component was acquired from the absolute velocity obtained in particle image velocimetry. By comparing with experimental results, it was found that flow instability occurs at the position of maximum K. The flow stability reduces with an increasing flow rate. The research results provide a theoretical basis for the optimization design of a centrifugal pump. 展开更多
关键词 centrifugal pump flow instability three-dimensional particle image velocimetry numerical simula-tion energy gradient
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Blow-up of critical norms for the 3-D Navier-Stokes equations
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作者 WANG WenDong ZHANG ZhiFei 《Science China Mathematics》 SCIE CSCD 2017年第4期637-650,共14页
Let u = (Uh,U3) be a smooth solution of the 3-D Navier-Stokes equations in R3 × [0, T). It was proved that if u3 ∈ L^∞(0,T;Bp,q-1+3/p(R3)) for 3 〈 p,q 〈 oe and uh ∈ L^∞(0, T;BMO-1(R3)) with uh(... Let u = (Uh,U3) be a smooth solution of the 3-D Navier-Stokes equations in R3 × [0, T). It was proved that if u3 ∈ L^∞(0,T;Bp,q-1+3/p(R3)) for 3 〈 p,q 〈 oe and uh ∈ L^∞(0, T;BMO-1(R3)) with uh(T) ∈ VMO-1(R3), then u can be extended beyond T. This result generalizes the recent result proved by Gallagher et al. (2016), which requires u ∈ L^∞(O,T;Bp,^-11+3/P(R3)). Our proof is based on a new interior regularity criterion in terms of one velocity component, which is independent of interest. 展开更多
关键词 Navier-Stokes equations interior regularity criterion BMO space Besov space
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Design and calibration of a new high-definition three-dimensional laparoscopic system
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作者 Jia TANG Li-qiang WANG Bo YUAN Hong JIANG Qi-ming ZHU 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2015年第1期79-84,共6页
We present a high-definition (HD) 3D laparoscopic system including a dual channel optical system, two cameras, a camera control unit (CCU), and an HD 3D monitor. This laparoscopic system is capable of outputting d... We present a high-definition (HD) 3D laparoscopic system including a dual channel optical system, two cameras, a camera control unit (CCU), and an HD 3D monitor. This laparoscopic system is capable of outputting dual high-definition videos and providing vivid 3D images. A modified pinhole camera model is used for camera calibration and a new method of depth measurement to improve precision. The average error of depth measurement measured by experiment (about 1.13 mm) was small in proportion to the large range in distance of the system (10-150 mm). The new method is applicable to any calibrated binocular vision system. 展开更多
关键词 Dual optical channels Three dimensional Camera calibration Pinhole model Depth measurement Laparoscopicsystem
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