道路照明常用光源在中间视觉条件下的光效

因为道路照明亮度水平一般在中间视觉范围内,所以目前依据明视觉光谱光视效率函数确定光源在道路照明条件下光效的方法是不合适的.为了得到道路照明常用光源在中间视觉条件下的光效,正确选择道路照明光源和使道路照明设计达到节能要求,采用中间视觉的实用模型和国内外利用多种方法得到的实验数据,研究高压钠灯和金属卤化物灯(镝灯)这2种道路照明常用光源在中间视觉条件下的光学特性,计算出了这2种光源在中间视觉条件下的光效,分析了在中间视觉条件下的光效随适应亮度水平变化而变化的规律,并提出应根据道路照明所需要的亮度水平选择合适的照明光源.     

基于反应时间的道路照明功率密度确定方法

由于金卤(MH)灯和发光二极管(LED灯)作为道路照明光源时,其照明功率密度(LPD)没有标准可依,为此,选取色温为2 000 K的高压钠灯(HPS)、色温为4 800 K的MH灯和色温为7 200 K的LED灯作为照明光源。利用道路照明反应时间测试装置分别进行反应时间实验,得到道路照明亮度水平下MH灯和LED灯相对于HPS灯的亮度对比系数,确定其相对HPS灯的相对光效,并在此基础上计算得到MH灯和LED灯作为道路照明光源时的照明功率密度标准值。研究结果表明:将4 800 K的MH灯作为道路照明光源时,所需LPD为HPS灯的1.3倍左右,将7 200 K的LED灯作为道路照明光源时,所需LPD为HPS灯的47%~89%。     

中间视觉条件下的道路照明反应时间

道路照明中的亮度水平应属中间视觉范畴.而世界各国的现行道路照明标准均是在明视觉条件下确定的,这与中间视觉效果差别很大,由此带来的问题将造成照明质量的评价误差.为此,通过反应时间来研究中间视觉条件下的道路照明已成为该学科国际上的前沿研究课题.对此,文章介绍了采用自行研制的中间视觉反应时间测试系统进行光源光效的研究.该系统以不同光源形成中间视觉光环境,用变化的光斑模拟夜间行车道路前方可能出现的障碍物,并分别在不同背景亮度、视标对比度和视标偏心角的条件下,利用电子快门记录受测人员确认光斑的反应时间.通过对大量实测数据的回归分析,拟合出不同实验条件下反应时间与背景亮度的函数表达式,从而得出金卤光源视觉功效高于钠灯光源的结论.文中对测试系统的构造、工作原理、实验方法及数据处理结果进行了分析与讨论.该项研究成果对创建中间视觉条件下的可见度模型提供了实验依据,为中国道路照明工程的具体实施和实际改进有很好的借鉴意义.     

道路照明条件下驾驶员瞳孔大小变化规律

为了研究道路照明条件下驾驶员瞳孔大小随亮度水平的变化规律,采用道路照明反应时间测试装置和iView X眼动仪,对4位被测者在分别由高压钠灯(HPS)、金卤灯(MH)和LED灯作为光源提供的13种背景亮度下的瞳孔面积进行测量。结果表明,在道路照明条件下,人眼瞳孔与背景亮度之间基本呈负指数关系,人眼瞳孔面积随背景亮度的变大而减小,且减小的速度随背景亮度的变大而减小,瞳孔大小在达到某背景亮度水平后逐渐趋于稳定;对于实验所用的3种光源,人眼瞳孔大小在背景亮度为0.7～1.2cd/m2的范围内会出现波动。     

白绿色LED道路光源小目标可见度研究

小目标可见度是衡量驾驶安全性的重要指标,但夜间驾驶处于中间视觉的复杂环境,导致作为可见度水平的重要参数的阈限亮度差难以被准确评价。本文通过中间视觉环境下建立的背景亮度/敏感波长关系模型,对道路照明光源进行基于敏感波长的阈限亮度差研究,以实现对白绿色LED光源不同主波长的可见度研究。从负对比修正系数Kf和识别时间修正系数Kt出发,建立中间视觉阈限亮度差修正模型,提升可见度算法精确度,准确衡量照明光源安全性。利用小目标可见度算法在RP-8-00标准建议的夜间驾驶视看条件(视张角7.45′、驾驶员年龄60岁、识别时间0.2 s)下,对机动车道路面照明亮度环境(0.75-3.0 cd/m~2)中的照明灯具进行评价,得出在此视看环境下以528 nm作为主波长的白绿色LED光源可见度最高的结论,并通过道路平均亮度和反应时间验证了该光源相比传统照明光源安全性更好。     

用视觉功效法探究适用于道路照明的新型光源

应用视觉功效法,采用自行研制的"道路照明反应时间测定仪",分别对高压钠灯(HPS)、发光二极管(LED)及电磁感应灯(LVD)三种光源进行了中间视觉下的反应时间和间接的光谱能量分布实测.并根据实测结果,计算出LED和LVD对HPS的亮度对比系数、相对光效及折算光效,由此得出了LED照明安全及节能效果优于HPS和LVD的结论.对光谱能量分布实测结果进行了分析,指出了三种光源光谱特性的内在关系及异同点,为进一步的理论研究提供了实验依据.     

教室照明条件下瞳孔大小变化规律

为研究教室照明条件下学生瞳孔大小随亮度水平的变化规律,选择3位大学生作为被试者,采用iView X眼动仪,通过模拟教室照明条件的教室照明瞳孔大小测量系统实验,对3种教室常用色温(2 700 K,4 000 K,6 500 K)荧光灯光源提供的5种背景亮度下的瞳孔面积变化值进行测量.结果显示,3种色温荧光灯下的瞳孔面积与背景亮度呈负指数函数关系;在教室照明条件下人眼瞳孔面积随背景亮度的变大而减小,并逐渐趋于稳定;在相同背景亮度下,色温越高的荧光灯照明时瞳孔面积越小.     

视觉功效法及其在道路照明安全研究中的应用

基于司辰视觉理论和中间视觉理论,研究了高压钠灯和金属卤化物灯在不同亮度条件下的发光效率,进行了反应时间实验,根据实验结果计算出在中间视觉条件下金属卤化物灯对高压钠灯的亮度对比系数。结果表明,金属卤化物灯的司辰视觉发光效率是高压钠灯发光效率的3倍多;当亮度大于3 cd/m2时高压钠灯的发光效率高于金属卤化物灯,当亮度在0.01~3 cd/m2时金属卤化物灯的发光效率高于高压钠灯;在道路照明条件下,金属卤化物灯照明的反应时间效果比高压钠灯好。     

不同环境温度下照明光源对人体体温调节的影响

研究人在不同环境温度下,光源照度和色温对人体体核温度、皮肤平均温度和皮肤血流量的影响,探索光源照明对人体体温调节的作用.对8名受试者在人工气候室不同环境温度(18,30 °C)、光源照度(300,1 000 lx)和色温(3 000,6 000 K)下的体核温度、平均皮肤温度和皮肤血流量进行了60 min的测量和记录.结果表明：无论在高温还是低温条件下,当人体暴露于低色温光源下时人的体核温度较高色温光源下时高;在较低的环境温度下,平均皮肤温度和皮肤血流量在冷色温光源下的值高于低色温光源下的值;在较高温度下,平均皮肤血流量和皮肤温度在低色温光源下的值高于冷色温光源下的值.因此,在环境温度发生变化时,光源照明对人体的热调节起着一定的作用,在环境高温下以运用高色温光源为宜,反之亦然.这提示人们在不同的环境温度下对于光源照度和色温的选择是一个值得重视的问题,除视觉需要外,选择时还应考虑人体生理功能的平衡和舒适感.     

中间视觉道路照明光视效能最大值研究

本文给出了在中间视觉道路照明条件下光视效能最大值模型。在人眼驾驶行为反应时间模拟系统中选取若干受测者进行实验,通过实验数据推导出基于反应时间的光源主波长和中间视觉背景亮度关系模型。并以该关系模型为基础,给出了中间视觉条件下,基于背景亮度和光源主波长的光视光效能最大值模型。利用最大值模型探讨了光源的节电性能,得出基于中间视觉光视效能最大值的照明功率密度关系函数以及528 nm主波长照明光源的节能性最佳的结论,并结合实验验证了此结论的正确性。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to