Early warning research on salt-alkalization desertification in western Songnen Plain

Desertification is an environmental issue in the world. The salt-alkalization desertification land area formed by both primary and secondary salt-alkalization has extended in a large scale, which has become a significant eco-environmental problem. Based on the characteristics of eco-environment and the situation of desertification in western Songnen plain, this paper reports the analyzes of its formation in background and cause. An early warning system on the salt-alkalization desertification is established and the GIS technology is used to abstract the information of desertification evaluation index. Supported by the integrated technology of the GIS and ANN, the orientation and quantitative result of desertification are gained, which is helpful to the eco-environment protection and resource development in western Songnen Plain.     

Is Pre-Eruptive Null Point Reconnection Required for Triggering Eruptions?

We study the magnetic field evolution and topology of the active region NOAA 10486 before the 3B/X1.2 flare of October 26, 2003, using observational data from the French–Italian THEMIS telescope, the Michelson Doppler Imager (MDI) onboard Solar and Heliospheric Observatory (SOHO), the Solar Magnetic Field Telescope (SMFT) at Huairou Solar Observation Station (HSOS), and the Transition Region and Coronal Explorer (TRACE). Three dimensional (3D) extrapolation of photospheric magnetic field, assuming a potential field configuration, reveals the existence of two magnetic null points in the corona above the active region. We look at their role in the triggering of the main flare, by using the bright patches observed in TRACE 1600 Å images as tracers at the solar surface of energy release associated with magnetic reconnection at the null points. All the bright patches observed before the flare correspond to the low-altitude null point. They have no direct relationship with the X1.2 flare because the related separatrix is located far from the eruptive site. No bright patch corresponds to the high-altitude null point before the flare. We conclude that eruptions can be triggered without pre-eruptive coronal null point reconnection, and the presence of null points is not a sufficient condition for the occurrence of flares. We propose that this eruptive flare results from the loss of equilibrium due to persistent flux emergence, continuous photospheric motion and strong shear along the magnetic neutral line. The opening of the coronal field lines above the active region should be a byproduct of the large 3B/X1.2 flare rather than its trigger.     

青藏高原的范围

青藏高原确切的范围各家说法不一,本文根据青藏高原巨构造地貌特征,提出以高原面及其海拔高度为确定青藏高原范围的依据,对青藏高原具体范围特别是东、东南的边界作了较详细的讨论。     

陕西秦巴山区农业自然资源开发利用

农业自然资源据其在农业利用过程中的地位可分为两类:一类是生成农业自然资源的环境,另一类为可资直接利用的自然生成物(即狭义的农业自然资源)。陕西秦巴山区自然环境的主要特点是:复合山体高峻庞大,地跨暖温带和北亚热带,垂直分异明显。区内有:森林、草场、野生生物、林特产与农作物等多种农业自然资源。据此,提出了本区农业自然资源的开发利用途径。     

凤太矿田层控铅锌(铜)矿床的成矿物质来源探讨

秦岭凤太矿田层控铅锌(铜)矿床的金属物质、硫和成矿溶液主要来自深部基底的岩石,属海底喷流—沉积成因矿床。从这一理论认识出发可进一步分析控矿地质条件及今后在该区有效地寻找同类矿床。     

激变变星0623＋71的光谱研究

本文提出了激变变星０６２３十７１的４个时间分辨光谱，覆盖轨道周期的７３％．其中的３个谱清楚地显示了各种光谱特征随轨道运动的变化，在流量、能谱以及谱线轮廓方面的这种变化正是对一个倾角不太大的激变变星所期望的．然而另一个曝光对分钟的谱，流量和视向速度与预期的相比都太大，很难加以解释，可能它是一次象ＡＥＡｑｒ中观测到的跃发事件．     

现代天文选址中的视宁度（Ⅱ）

在文献」１「４ 基础上，根据近年文选址实践中提出的问题，先进一步讨论了大气相干直径和时间的的物理和意义，然后强调了自由大气湍流的天文成像效应及选址中进行研究和测量的重要性。最后对差分像运动方法测量视宁度的定标和系统误差等问题作了分析。     

Energy flow in Branchiura sowerbyi (Oligochaeta: tubificidae) in a shallow macrophyte-dominated lake, Biandantang Lake

The energy flow ofBranchiura sowerbyi was studied for the first time in China in a shallow macrophytic lake, Biandantang Lake, Hubei Province. The energy flow was calculated from the measurement of flesh production (12.5241kJ/m²a), egestion (517.7302kJ/m²a), metabolism (38.3273 kJ/m²a), and excretion (4.3798kJ/m²a). The net growth efficiency of the species is about 22.7%, which accords well with the generally reported value for oligochaetes. In addition, the relationship between starvation respiration (R, mgO₂/ind·d), wet weight (Ww, mg) and temperature (T, °C) were also measured, with the regression function beingR=0.008Ww^0.736 e^0.050T. Project supported by NSFC (30270278, 3960019), the foundation of the government of Hubei Province (No. 2000J109), and the foundation of Ecological Station, CAS in the Institute of Hydrobiology.     

巴颜喀拉山东段及其邻区大地电磁测深成果地质解释

本文主要依据青海省囊歉至大河坝大地电磁测深成果,并结合重力资料对巴颜喀拉及南北两侧地区的壳幔结构进行了地质解释。指出了该区壳幔存在4个明显的低阻层,并简述了它们的形态特征,推断了其地质含意。认为昆中断裂带与昆南断裂带间是一个巨大的构造混杂岩带,影响深度亦很大。推断该区可能存在太古代地层。划出了8条壳幔断裂带,认为昆中断裂应是塔里木—华北板块与华南板块的分界线。