2013年3—5月T639、ECMWF及日本模式中期预报性能检验

为了更好地应用T639模式中期预报产品,对2013年3—5月T639模式中期预报时效产品进行了天气学检验,并与:ECMWF、日本模式进行了对比分析。结果表明:三家模式均对亚洲环流形势的调整和演变具有较好的预报性能。综合看来,ECMWF模式对主要系统及气象要素的预报最接近实况;日本模式和T639模式次之。另外,选取了2013年3月8—9日的沙尘天气过程进行检验,发现ECMWF模式对于引发此次沙尘天气的地面高压系统中期预报指示意义最好。     

极地驻留时间对认知功能的影响

记忆、空间认知等基本认知功能是影响考察人员能否在南极高寒、单调、孤立、封闭的极端环境下完成复杂任务的基础认知能力.关于极地驻留时间长短对认知功能的影响尚缺乏专门的研究.本文通过计算机记录反应时技术,追踪自度夏到越冬中期,中国南极第25次队长城站越冬人员短时再认、记忆搜索、空间认知能力随驻留时间延长发生的变化.结果表明:...     

A proposed frequency spectrum for fully developed wind waves by revisiting P-M spectrum

It is generally believed that the equilibrium range of wind wave spectrum is in the form of the −4 rather than −5 power law. However, in the widely applied P-M spectrum the equilibrium range is given in the form of −5 power law. In the present paper, a spectrum for full development of wind waves is proposed using the form of the Neumann spectrum, but adopting the −4 power law for the equilibrium range. The proposed spectrum has been verified with NDBC buoy data and could be a substitute for the P-M spectrum.     

一种适用于长弧段的初轨计算方法

根据单位矢量法测轨原理，在人造卫星初轨计算的单位矢量法基础上，给出了一种适用于长弧段的初轨计算方法．该方法既适用于长弧段，也适用于短弧段；适用于各种不同类型的观测资料和任意偏心率、任意轨道倾角的人造地球卫星；有利于提高初轨测定精度；并改善整个计算收敛性．特别需要指出的是，该方法与有摄初轨计算的单位矢量法相结合，为单位矢量法从初轨计算推广到轨道改进打下了坚实的基础．     

AGB stars in the Magellanic Clouds

The stars that will be detectable in the Magellanic Clouds by the DENIS and 2MASS near infrared surveys are enumerated. All thermally-pulsing AGB stars will be observable in I, J, H and K, along with the top two magnitudes of both the early-AGB and the first giant branch. All carbon stars will be visible, and normal (N type) C stars will be easily distinguished by their large J-K colours. However, it will not be possible to separate faint, warm C stars from K and M stars using the photometry alone. Photometry of AGB stars in clusters will allow an accurate evaluation of the AGB tip luminosities as a function of initial mass. Random phase K magnitudes of LPVs and Cepheids should provide a better measure of the LMC tilt and distortions in the SMC. The K survey should turn up 100 to 150 objects undergoing superwind mass loss, these objects being OH/IR stars and the dust-enshrouded C star equivalents of OH/IR stars. It is shown that crowding should not be a problem even in the LMC bar.     

超长隧洞施工测量若干问题研究

超长隧洞施工测量属于超规范作业,为保证超长隧洞贯通,必须对超长隧洞施工测量进行研究。对隧洞施工测量中洞口控制网布设、数据处理及其误差对贯通的影响与洞内基本控制网的布设、平差及检核方法等若干问题进行了研究,所得成果已运用于引黄入晋工程中的南干5#和7#超长隧洞施工测量中,确保了两超长隧洞的顺利贯通。     

UV and optical spectral properties in early-type galaxies

We investigate UV and optical spectra of a sample of nearby early-type galaxies with evidence of nuclear line emission. The spectral signatures of various contributors to the UV, such as the interstellar medium and various stellar populations are analyzed and compared with the optical spectral properties. We discuss the impact of these effects on the observational properties of galaxy evolution. This revised version was published online in August 2006 with corrections to the Cover Date.     

GENERAL THEORY FOR APPARENT ENERGY DISTRIBUTION OF SEA WAVES

lwrRODUcrIONSeawavesarerecognindasacrucialfaCtorinengineeringandoffshorestruCturede-signsandconstitutCanimPoftantpartintheoreticalstudiesandapplicati0ns.TocopewiththecomPlexityofseawaves,alinearrandomwaveshomogeneousandstationarythe-oryisintrodutalwhereintwomodeIsdescribetheoonnsurfaeedisplacement.Inthefirstone,thesurfaeedisplaerentchangingwithlocationandtheisexpnssedingeneralitalFouriertransform,wherethefrequencyspeCtrumE(co)andwavenumberspodrumEoocanbedefined.Theotherwavemodelisbasedo…     

CSRH模拟接收机设计

本文叙述了日像仪实验的方案，双天线干涉仪中模拟接收机的结构，灵敏度，动态范围，噪声，增益的各级分配等问题，基于实验方案设计了日像仪模拟接收机。     

空间关系描述的9-交模型

首先对４元组、９元组描述框架进行了剖析，指明了从４元组向９元组扩展的意义，同时也论述了９元组存在的缺点和不足及其产生的原因。最后，提出用空间实体的势力范围（ＡＶ）代替原９元组中的“补”作为空间实体的外部，并结合空间实体的边界（Ａ）、内部（Ａ°），构成新的基于空间实体势力范围的空间关系描述的９－交模型（简称ＮＩＶ），并对其特点进行了分析。