山西省高速公路大雾预报方法研究

通过对山西省已经运营和拟建的高速公路沿线17个气象站1971年～2000年气候资料的分析,应用统计预报方法和诊断分析方法对山西省高速沿线大雾预报进行了研究。结果表明,这两种预报方法在实际工作中是可行的,将两种方法集成后预报效果较好。     

The influence of magnetic fields on neutrino-dominated accretion disc

We consider the influence of magnetic fields on the model of neutrino-dominated accretion flows (NDAFs) for gamma-ray bursts (GRBs) via the assumption that the accretion rate of the disc is totally caused by the torque of the Lorentz force, i.e. the magnetic braking of large-scale magnetic fields and magnetic viscosity of small-scale magnetic fields. We calculate the structure, composition, luminosity of neutrino emission and the Poynting flux, and the rate of mass loss driven by neutrino heating or launched centrifugally by large-scale magnetic fields, based on the physical condition of the magnetized NDAFs. It is shown that the magnetized disc is favourable to interpret the diverse prompt emissions as well as the X-ray flares observed in the early afterglow of GRBs.     

年轻星天体的质量

质量是恒星最基本、最重要的物理量之一,它在恒星形成和演化过程中起着至关重要的作用.年轻星天体的形成机制以及早期演化过程是彻底解决恒星形成问题的关键所在,而年轻星天体形成过程中的物质下落、质量吸积以及外流等物理过程都与年轻星天体的质量密切相关.该文介绍了确定年轻星天体质量的一些常用方法,包括利用开普勒定律的动力学方法、赫罗图方法、年轻星天体脉动方法和磁层吸积方法等.并对这些方法的适用范围及测量精度进行了评述,还综述了各种方法的研究进展及未来可能的发展.     

An orbital period investigation of the Algol-type eclipsing binary VW Hydrae

Orbital period variations of the Algol-type eclipsing binary, VW Hydrae, are analyzed based on one newly determined eclipse time and the other times of light minima collected from the literature. It is discovered that the orbital period shows a continuous increase at a rate of dP/dt = +6.34×10-7 d yr-1 while it undergoes a cyclic change with an amplitude of 0.0639 d and a period of 51.5 yr. After the long-term period increase and the large-amphtude period oscillation were subtracted from the O-C curve, the residuals of the photoelectric and CCD data indicate a small-amplitude cyclic variation with a period of 8.75 yr and a small amplitude of 0.0048d. The continuous period increase indicates a conservative mass transfer at a rate of dM2/dt = 7.89×10-8 M⊙ yr-1 from the secondary to the primary. The period increase may be caused by a combination of the mass transfer from the secondary to the primary and the angular momentum transfer from the binary system to the circumbinary disk. The two cyclic period oscillations can be explained by light-travel time effects via the presence of additional bodies. The small-amplitude periodic change indicates the existence of a less massive component with mass M3 > 0.53 M⊙, while the large-amplitude one is caused by the presence of a more massive component with mass M4 > 2.84 M⊙. The ultraviolet source in the system reported by Kviz & Rufener (1987) may be one of the additional components, and it is possible that the more massive one may be an unseen neutron star or black hole. The rapid period increase and the possibility of the presence of two additional components in the binary make it a very interesting system to study. New photometric and high-resolution spectroscopic observations and a detailed investigation of those data are required in the future.     

对Munsell空间明度与亮度因数关系式的改进

采用神经网络的函数逼近功能对Munsell新标系统中表示色样知觉色的明度值V与亮度因数Y之间的函数关系式进行了修正,消除了原关系式中V=9.91与 Y=100%相对应、而 V=10 却与Y=102.57%相对应的弊端,从而满足V=10和Y=100%都对应于理想白的条件.     

珠海市横琴新区地质灾害分布特征及易发性评价

近年来,横琴新区地质灾害较为频发且分布广泛,随着经济发展,地质灾害已成为阻碍城市发展的重要地质环境问题.研究根据地质灾害的不同成因,将区内地质灾害分为斜坡类地质灾害和软土沉降类地质灾害.通过对研究区各类地质灾害的调查与分析,总结出区内地质灾害分布特征;从地质环境条件、地质灾害现状和人类活动3个方面着手,构建适用于横琴新...     

Short-Term Periodicity in Solar Mean Magnetic Field during Activity Maximum and Minimum Periods

The short-term periodicity in the solar mean magnetic field (SMMF) observed at the Wilcox Solar Observatory during the last four activity cycles is investigated by using Lomb?CScargle periodograms. Our results show that the SMMF has main periods of about 27, 13.5, and 9 days in both the maximum and minimum years of each activity cycle. The SMMF has the most dominant period of about 27 days during the activity maxima. However, during the activity minimum years the 13.5-day periodicity is the most significant, except for the minimum of 1984??C?1986. These results indicate that the distribution of active regions in the activity maximum years is quite different from that in the minimum years.     

Research on Estimating Water Storage of Small Lake Based on Unmanned Aerial Vehicle 3D Model

Water Resources - Lake Water storage can be estimated based on Lake Boundary and lakebed terrain. The boundary of a lake can be extracted from the remote sensing satellite image or the Unmanned...     

2021年3—5月全球火山活动简报

正1)吉林省地震局,长春1301172)中国地震局火山研究所,长春130117     

A new mixing equation for bed material composition in bed form dominant conditions

Vertical mixing beneath the bed surface and its effect on sediment composition has long been underestimated. This paper proposes a mixing equation to illustrate the temporal and spatial variations of bed material composition for bed form dominant rivers. A continuous mass conservation equation for elevation-specific nonuniform bed material composition is initially presented. A vertical mixing equation is finally derived as a diffusion-type partial differential equation with a source term charact...