Response of canopy quantum yield of alpine meadow to temperature under low atmospheric pressure on Tibetan Plateau

An open-path eddy covariance system was set up in Damxung rangeland station to measure the carbon flux from July to October, 2003. The canopy quantum yield (α) of alpine meadow was calculated by the linear function between the net ecosystem carbon dioxide exchange (NEE) and the photosynthetic active radiation (PAR) under low light, and how it was influenced by the temperature was also discussed. Results showed that the canopy or decreased almost linearly with temperature, with the decrease in every 1℃increase of temperature similar to those measured on leaf level of C3 plant. At the beginning, the decrease of canopyαwith temperature was 0.0005 umol CO2·μmol-1 PAR; while it increased to 0.0008μmol CO2·μmol-1 PAR in September, showing a rising trend with plant growing stages. Compared with the canopy a calculated with rectangular hyperbola function, the value in the paper was lower. However, the method advanced here has the advantages in examining the relationship betweenαand the key environmental factors, such as temperature.     

我国东部滨岸侵沉变异规律初探

滨岸地带自然环境多变,地质环境极为脆弱,但在社会经济发展中起着极为重要的作用。着重分析我国东部滨岸侵沉变异特征,研究滨岸侵沉变异地域分异规律与成因规律。     

软岩边坡变形破坏规律及其 对城市设施的影响

以抚顺西露天矿大规模倾倒滑移变形体变形规律研究为例,探讨受软弱夹层控制的软岩边坡变形破坏规律及其变形破坏对城市工业设施的影响。     

Study of charge structure and radiation characteristic of intracloud discharge in thunderstorms of Qinghai-Tibet Plateau

The comprehensive observations on lightning discharges were conducted in Naqu area of Qinghai-Tibet Plateau in summer of 2002. The electric structures of thunderstorms and the characteristics of lightning discharges at initial stage were analyzed by using the observation data. The results show that most of intracloud (IC) lightning flashes were polarities inverted in thunderstorms with tripole electric charge structure and occurred between negative charge region located in the middle of the thunderstorm and positive charge region located at the bottom of the thunderstorm. The radiation characteristics of discharge processes in cloud with longer lasting time involved in Cloud-to-Ground (CG) lightning flashes were similar to that of IC discharges.A lot of radiation pulses were produced in these discharge processes. Because the IC discharges took place at the bottom of thundercloud and were near the ground, they may produce more serious damage to equipment on the ground therefore should not be neglected in lightning protection.     

Sedimentary environment and development controls of the hydrocarbon source beds:Middle and Upper Proterozoic in northern North China

Problem on development control of marine source bed hold in Chinese petroleum industry progression. The Hongshuizhuang Formation,Tieling Formation and Xiamaling Formation in the Middle and Upper Proterozoic are important hydrocarbon source beds in northern North China, and investigation of their sedimentary environments and the controls has great significance for petroleum exploration in North China. Based on sedimentology (sequence stratigraphy), palaeoecology, sedimentary geochemistry, and sedimentary palaeogeography, their development pattern is discussed. All these studies indicate that the development controls of the hydrocarbon source beds include a favorite palaeogeographic location, exceeding propagation of biomes in low and middle latitudes, anoxic environments, enrichment of phosphorus element and the adsorption of clay minerals during the preservation of organic matter in the marine carbonates.     

Experimental research on reservoir sensitivity to stress and impacts on productivity in Kela 2 Gas Field

Kela 2 Gas Field, with high formation pressure (74.35MPa), high pressure coefficient (2.022) and difficulty of potential test and evaluation, is the largest integrated proved dry gas reservoir in China so far and the principal source for West-East Gas Development Project. In order to correctly evaluate the elastic-plastic deformation of rocks caused by the pressure decline during production, some researches, as the experiment on reservoir sensitivity to stress of gas filed with abnormal high pressure, are made. By testing the rock mechanic properties, porosities and permeabilities at different temperature and pressure of 342 core samples from 5 wells in this area, the variations of petro-physical properties at changing pressure are analyzed, and the applicable inspection relationship is concluded. The average productivity curve with the reservoir sensitivity to stress is plotted on the basis of the research, integrated with the field-wide productivity equation. The knowledge lays a foundation for the gas well productivity evaluation in the field and the gas field development plan, and provides effective techniques and measures for basic research on the development of similar gas fields.     

The Lanmuchang Tl deposit and its environmental geochemistry

Tl is a dispersed element and it seldom occurs in the form of independent minerals.The world annual production of Tl is about 13 ton, most of which is by-product separated from non-ferrous metal products. Lanmuchang is the only large-size independent Tl deposit in the world. Bio-enrichment and hydrothermal reworking are the two important metallogenic mechanisms of this Tl deposit. Samples of plant and animal organs and villagers’ urine as well as hair and nail (toenail) samples from the Tl mining district were analyzed. Analytical results showed that the contents of Tl, Hg and As are high, suggesting that the residents and villagers in the mining district have been affected by Tl-Hg pollution, and on the other hand, they can serve as the guidelines for ore prospecting. The contents of Tl, Hg, and As in human beings and other organic bodies depend largely on the background values of these metals in rock, ore, soil and water.     

Composition of plagioclases in volcanic rocks of King George Island, Antarctica with reference to the petrogenetic significance

Plagioclases occur mainly as phenocrysts in volcanic rocks of King George Island, South Shetland Islands, West Antarctica. In basaltic andesites and andesites of Keller Peninsula and Ullman Spur (Admiralty Bay), they are high structure state labradorite-andesines; and in high-A1 basalts and basaltic andesites of Barton and Weaver peninsulas (Maxwell Bay), they are high structure state bytownite-anorthites.∑REE, La/Yb ratios and δEu values of plagioclases from Admiralty Bay are higher than those from Maxwell Bay. All plagioclases have rather identical chondritenormalized transitional element distribution patterns, probably reflecting that crystal structure rather than composition of plagioclase controls their diversity. Compositions of plagioclases depend chiefly on those of their host rocks, compositional differences of plagioclases reveal that basaltic magmas in the Admiralty Bay area are more evolved than in the Maxwell Bay area.     

The material conditions for research in France from 1600 to 1850: Physics,chemistry and astronomy

The income of the scientists in France during the 17th to the middle of the 19th century is reviewed and compared to the cost of their instruments. Only a small number of scientists received enough public money to be able to do full-time research; this number increased substantially after the Revolution. Most scientists had to have other sources of income, in particular to be able to purchase their instruments. Large research projects, generally decided and financed by the Academy of Sciences, took place during this period, requiring collaborative interdisciplinary efforts and a considerable logistics: they anticipate our present cooperative programs and giant research facilities.     

钢筋混凝土管桩反射波法的三维有限元分析

对桩-土系统用三维有限元模型和Wilson- 直接积分法计算钢筋混凝土管桩顶面的瞬态动力响应,并由此分析了管桩顶面不同测点的反射波信号特征及其与桩身缺陷的对应规律。计算结果表明：管桩顶部波传播的三维效应对桩身浅部局部缺陷深度的判断有较大的影响,所得结论对由反射波法检测管桩全截面断裂和局部缺陷以及传感器的合理布置有较大的指导作用。