Physics of Seismic Source Ⅲ. Statistical Mechanics of Earthquakes

The statistical mechanics of earthquakes adopts the concepts and methodology of statistical mechanics, especially the theory of critical phenomena, in studying the preparation, initiation, propagation and healing of earthquake rupture, which forms a new branch in the physics of seismic source in recent years. This article introduces to the fundamental concepts of the statistical mechanics of earthquakes. The introduction includes the seismic Hamiltonian, percolation model, earthquake rupture nucleation, and Burridge-Knopoff spring-block model. It is pointed out that some of the statistical mechanical models of earthquakes have a sound seismological basis. There is a smooth "transition" from the "classical" theory to the "modern" theory of seismic source.     

地震动力分析的经典方法与现代计算技术

回顾了体系地震动力分析的历史过程，并对地震动力分析的传统理论方法、近似方法和现代计算技术从新的角度加以阐述，同时给出体系地震动力分析的应用前景，以促进经典的传统理论方法、近似方法和现代计算技术的综合和在实际工程中的应用，形成系统而完整的地震动力分析体系。     

On the calculation of spurious velocity signal produced by atmospheric differential extinction in whole-disk oscillation measurements

The systematic diurnal signal drift in full-disk solar oscillation measurements has been calculated taking into account differential rotation, the inclination of the rotational axis of the Sun with respect to the picture plane, the limb-darkening function and a realistic estimation of the sky transparency, slightly variable during the day. An illustration of this method on the Kumbel (U.S.S.R.) IRIS data is presented and discussed.     

Models of neutron stars in generalized bimetric theory of gravitation

Yerevan State University; Institute of Applied Physics Problems, Armenian Academy of Sciences. Translated fromAstrofizika, Vol. 35, No. 1, pp. 121–129, July–August, 1991.     

IAG2001年科学大会与大地测量学的最新进展

扼要报导了国际大地测量学术界的一次重要会议－IAG2001年科学大会。根据会议的学术报告，对坐标系统的统一与协调，全球重力场研究，导航卫星的应用，地壳形变与地球动力学等方面的研究进展作了详细介绍。     

New Criterion for Lunar Crescent Visibility

A new criterion for lunar crescent visibility has been established using 737 observations, almost half of them obtained by the Islamic Crescent Observation Project (ICOP). This criterion is based on two variables, viz. the topocentric arc of vision and the topocentric crescent width. The new model is able to predict the visibility of the lunar crescent both for naked eye and optically aided observations. From the database we found a Danjon limit of 6.4 degrees. Vice-President of “Crescents, Calendars and Mawaqeet Committee” of AUASS.     

长江三峡库区地震地形变监测研究

三峡地壳形变监测网络结合空间大地测量(GPS、InSAR)和传统大地测量的优点，在1998年以来的三峡工程建设期间和2003年水库首次蓄水中获取了大量监测成果。结果显示库区地壳运动的基本图像：垂直形变较为显著，主要来自因蓄水荷载而产生的形变，水平形变不明显．库区主要断层的活动性在蓄水期间有明显加强迹象。水准测量反映从1998年首期观测至2003年10月首次蓄水后的库区垂直位移．沉降范围较大；GPS给出了2003年蓄水前后库区的垂直位移，形变的范围主要集中在水库近岸区域。水准测量与GPS观测反应的垂直位移的量级基本一致，沉降的最大幅度在3～4cm左右。水准监测、GPS观测与重力监测结果有一定的对应性。从地壳形变监测与研究结果分析，近期负荷改变而诱发中强地震的可能性不大。     

THE ULTRASTRUCTURE OF SEPARATED AND CULTURED CELL OF PORPHYRA YEZOENSIS

There are many reports that cells (protoplasts) separated from the thallus of Porphyra by enzyme can develop to normal leafy thalli in the same way as monopores. But there are few investigations on the subcellular structure of the isolated vegetative cell for ccmparison with the subcellular structure of monospores. To clarify whether the separated and cultured cells undergo the same or similar ultrastructure changes during culture and germination as monospores undergo in their formation and germination, we observed their ultrastructure, ccxnpared them with those of the monospore and found that the ultrastructure of separated and cultured cells did not have the characteristic feature as that of monospore formarion, such as production of small and large fibrous vesicles, but was acccxnpanied by vacuolation andstarch mobilization like that in monospore germination. The paper also discusses the relations between monospores and separated and cultured cells.     

Study on Variation of Fitting Goodness of Relation Between Earthquake Frequency and Magnitude before Moderately Strong Earthquakes (Ms≥5.0)

In this paper,characteristics of spatial and temporal variation of linear fitting goodness before some moderately strong earthquakes(Ms≥5.0)in the eastern part of China(east of longitude 180)are studied according to the famous Gutenberg-Richter's relation expressed as lgN=a-bM,by using the moderate and small events that occurred in and around the source area.The results show that the linear goodness of fitting varies abnormally prior to these moderately strong earthquakes.In the early stage of the earthquake preparatory process,distribution of the energy released through small events in and around the source area is isostatic and the fitting goodness approximates 1,while the distribution of the energy turns to be isostatic before moderately strong earthquakes,leading to the obvious decrease of the linear goodness of fitting.This phenomenon could be a medium term anomaly and a medium term criterion for moderately strong earthquake prediction.