A modified numerical model for moisture-salt transport in unsaturated sandy soil under evaporation

Soil salinization, caused by salt migration and accumulation underneath the soil surface, will corrode structures. To analyze the moisture-salt migration and salt precipitation in soil under evaporation conditions, a mathematical model consisting of a series of theoretical equations is briefly presented. The filling effect of precipitated salts on tortuosity factor and evaporation rate are taken into account in relevant equations. Besides, a transition equation to link the solute transport equation before and after salt precipitation is proposed. Meanwhile, a new relative humidity equation deduced from Pitzer ions model is used to modify the vapor transport flux equation. The results show that the calculated values are in good agreement with the published experimental data, especially for the simulation of volume water content and evaporation rate of Toyoura sand, which confirm the reliability and applicability of the proposed model.     

Activity and kinematics of members of the TW Hydrae association

We present high-resolution echelle spectroscopy of 20 stars in 16 systems catalogued as members of the TW Hydrae association, and 16 stars identified as possible new members. We have calibrated the range of coronal and chromospheric activity expected for such young stars as a function of spectral type by combining our observations with literature data for field and open cluster stars. We also compute space motions for TWA members and candidate members with proper motion measurements, using two techniques to estimate distances to stars lacking direct trigonometric parallax measurements. The mean space motion of the four TWA members with known parallaxes is  ( U , V , W : −10.0, −17.8, −4.6) km s⁻¹  . 14 of the candidates have properties inconsistent with cluster membership; the remaining two are potential new members, although further observations are required to confirm this possibility.     

低轨道人造卫星(CHAMP、GRACE、GOCE)与高精度地球重力场——卫星重力大地测量的最新发展及其对地球科学的重大影响

评述了卫星重力大地测量的最新发展及其对地球科学的重大影响。为了更好地理解地球内部物理构造与海洋动力学，以及大陆，冰川和海洋的相互作用，改善现有地球重力场模型（包括精度和空间解析度）是非常重要的。IUGG等国际组织对此已经强调了很多年。最近，由德国的GFZ（GeoForschungsZentrum)，美国的NASA（National Aeronautics and Space Adminitration)以及欧洲宇航局ESA（European Space Agency)开发研制了最先进的地球监测技术－SST（Satellite-to-Sateilite Tracking)。其主要特点是利用现有的GPS连续追踪新发射低轨道卫星，并由低轨道卫星对地球重力场作精密观测。已经发射和即将发射的卫星有3颗：GHAMP（Challenging Mini-Satellite Payload for Geophysical Research an Application)已经于2000年发射；GRACE（Gravity Recovery and Climate Experimert)定于2002年发射；GOCE（Gravity Field and Steady-state Ocean Cirulation Explorer)计划2004年发射，它们可以统称为重力卫星。载有SST技术的人造卫星的主要目的是获得具有前所未有的高精度和高空间解析度的全球重力场和大地水准面模型，加强人们对地球内部构造的理解并为海洋和气象研究提供更好地参考。上述3个重力卫星工作在有明显区别的不同波谱内，它们有不同的科学应用，仅有一小部分重合。所以，就应用而言它们是完全互补的。它们在地球科学中的应用将是广泛的，特别对于固体地球物理学，海洋学以及大地测量学等领域，它们将会带来革命性的变化，其意义不亚于GPS。     

THE POSITION AND ROLES OF PORTS AND RAILWAYS IN THE EURASIA LAND BRIDGE TRANSPORTATION IN NORTHEAST CHINA

This paper systematically analyzes and proves the favorable factors of utilizing the ports and the railways in Northeast China for the Asia-Europe land bridge transportation. It will be more beneficial to Dalian Port and HaDa (Harbin-Dalian) and Binzhou (Harbin-Manzhouli) railways in Northeast China to the Siberia railway in Russia than 1) to other ports and the corresponding railways in China, 2) to the Nakhodka Port in Russia and the corresponding railways and 3) to the Chongjin Port in North Korea and the corresponding railways. This paper also puts forward the reform measures to adopt the ports and the railways in the northeast region in China for the land bridge transportation and the problems in transportation policies and management systems.     

太阳发电机理论研究进展

太阳发电机理论主要解释太阳磁场的起源和演化，是太阳物理中最基本、最重要的问题之一．对它的研究不仅具有重要的科学价值，而且对空间天气的预测和空间技术的发展有一定的影响．随着日震学的发展，该理论也得到了很大改进。从相关观测入手，综述了发电机理论需解释的观测事实，以及为发电机理论提供约束的太阳内部动力学结构；介绍了基本理论和近来的主流模型，并指出尚待解决的问题和进一步的努力方向。     

流星暴的航天定义

定义ZHR^*以每小时穿过1000平方公里天顶截面的，能在铝质表面打出直径不小于1厘米的弹坑的流星体数，作为流星群对航天安全威胁强度的定量标志，给出了从ZHR到ZHR^*的换算公式．用ZHR^*取代ZHR来评价20世纪90年代以来的一些强流星雨，发现1998年的贾可比尼(天龙座)流星雨对航天安全来说，是比公认的1999、2001、2002年3次狮子座流星暴强数倍的更强流星暴．     

沂水崔家峪玻璃用石英砂岩矿地质特征

沂水崔家峪玻璃用石英砂岩矿床赋存于早寒武世李官组砂岩段中．呈近水平的层状产出。因其岩石坚硬．矿体呈环山的平台状分布。矿体厚度大，矿石品级高，特级品矿石二氧化硅平均含量98．47％，铁杂质平均含量0．043％(选矿后，铁杂质含量可降至0．02％以下)，为一优质玻璃硅质原料矿床。矿石为细一中粒石英砂岩，粒度以中粒为主，矿石由碎屑颗粒和胶结物组成，碎屑成分含量为97％～98％．其中绝大部分是石英颗粒．具典型的砂屑结掏。该矿床属滨海陆源沉积矿床。     

济宁市嘉祥县石灰岩矿山地质环境评价与治理

在对嘉祥县石灰岩矿进行地质灾害危险性评估、矿山环境地质问题评价的基础上,建立了一套评价体系,其中地质灾害危险性评估分为2个评价指标,矿山环境地质问题评价分为2种要素3个指标,同时将矿山恢复治理难易程度也作为一个评价因子。评价过程中对各指标危害性大、中、小程度均单独赋值,然后将各指标的分值进行叠加,确定出矿山环境地质问题的等级,将概划出的13个评价单元分为极差、差、一般3个区。提出了强化矿山管理、植树造林、科学避让、修建拦水坝等保护与治理措施及建议。     

Precipitation patterns in flood season over China associated with the El Niño/Southern Osciliation

The precipitation patterns in flood season over China associated with the El Niño/Southern Oscillation (ENSO) are investigated, especially in the eastern China, using the rather long period rainfall data in this century. The results show that there were remarkable differences between the precipitation patterns in flood seasons of ENSO warm phase (El Niño year) and cold phase (La Niña year), as well as between the patterns in El Niño years and their following years. The most parts of China received below normal rainfall in flood season of the onset years of El Niño events, but the coastal area of Southeast China received above normal amounts. Comparatively, the most parts of China received above normal rainfall in flood season of the following years of El Niño events, but the eastern part of the reaches among the Huanghe (Yellow) River, the Huaihe River and the Haihe River, and the Northeast China received less. During ENSO cold phase, the reaches of the Changjiang (Yangtze) River and the North China received more amounts than normal rainfall in flood season of the onset years of La Niña events, and the other regions of China received less. In the following years of La Niña events, the coastal area of the Southeast China, the most part of the Northeast China and the regions between the Huanghe River and the Huaihe River received more precipitation during flood seasons, but the other parts received below normal precipitation.     

Porphyroblast inclusion-trail orientation data: eppure non son girate*!

Extensive examination of large numbers of spatially orientated thin sections of orientated samples from orogens of all ages around the world has demonstrated that porphyroblasts do not rotate relative to geographical coordinates during highly non-coaxial ductile deformation of the matrix subsequent to their growth. This has been demonstrated for all tectonic environments so far investigated. The work also has provided new insights and data on metamorphic, structural and tectonic processes including: (1) the intimate control of deformation partitioning on metamorphic reactions; (2) solutions to the lack of correlation between lineations that indicate the direction of movement within thrusts and shear zones, and relative plate motion; and (3) a possible technique for determining the direction of relative plate motion that caused orogenesis in ancient orogens.