对数周期偶极子天线的设计、制造和测试

文中所作的主要工作是为云南天文台十米抛物面设计、制造一付好的对数周期偶极子天线（ＬＰＤＡ）作馈源。工作有：（１）设计一对交叉的ＬＰ－ＤＡ；（２）分析ＬＰＤＡ特性；（３）估算抛物面的电特性；（４）讨论线极化向园极化转换的问题；（５）天线测量。ＬＰＤＡ的测量结果比较满意。该天线的方向图、平均输入阻抗、三分贝和十分贝波瓣宽度都在从０．５－１．５ＧＨｚ的频率范围内比较一致和稳定，变化很小。天线理论上的许多成就都是与数子计算机有关的。在文中，我们充分利用了计算机的功能来设计天线，分析天线特性，并从测量所得的所有数据文件中计算天线的参数。所编ＦＯＲＴＲＡＮ程序使这一切工作变得容易。最后，我们还讨论了用功率合成器实现线极化向园极化转换的各种情况     

关于改进的Encke方法中参考轨道的选择和校正

对于改进的Ｅｎｃｋｅ方法，选择适当的参考轨道是一个关键．然而，对于人造地球卫星长弧轨道计算，目前所给出的几种参考轨道均需要逐段校正，这将给定轨问题带来附加的复杂性．本文将仔细探讨如何选择参考轨道和减少校正次数．     

HCN fluorescence on Titan

The HCN emission features near 3 μm recently detected by Geballe et al. (2003, Astrophys. J. 583, L39) are analyzed with a model for fluorescence of sunlight in the ν₃ band of HCN. The emission spectrum is consistent with current knowledge of the atmospheric temperature profile and the HCN distribution inferred from millimeter-wave observations. The spectrum is insensitive to the abundance of HCN in the thermosphere and the thousand-fold enhancement relative to photochemical models suggested by Geballe et al. (2003, Astrophys. J. 583, L39) is not required to explain the observations. We find that the spectrum can be matched with temperatures from 130 to 200 K, with slightly better fits at high temperature, contrary to the temperature determination of 130±10 K of Geballe et al. (2003, Astrophys. J. 583, L39). The HCN emission spectrum is sensitive to the collisional de-excitation probability, P₁₀, for the ν₃ state and we determine a value of 10⁻⁵ with an accuracy of about a factor of two. Analysis of absorption lines in the C₂H₂ν₃ band near 3 μm, detected in the same spectrum, indicate a C₂H₂ mole fraction near 0.01 μbar of 10⁻⁵ for P₁₀=10⁻⁴. The derived mole fraction, however, is dependent upon the value adopted for P₁₀ and lower values are required if P₁₀ at Titan temperatures is less than its room temperature value.     

Low-cost volcano surveillance from space: case studies from Etna, Krafla, Cerro Negro, Fogo, Lascar and Erebus

 Satellite data offer a means of supplementing ground-based monitoring during volcanic eruptions, especially at times or locations where ground-based monitoring is difficult. Being directly and freely available several times a day, data from the advanced very high resolution radiometer (AVHRR) offers great potential for near real-time monitoring of all volcanoes across large (3000×3000 km) areas. Herein we describe techniques to detect and locate activity; estimate lava area, thermal flux, effusion rates and cumulative volume; and distinguish types of activity. Application is demonstrated using data for active lavas at Krafla, Etna, Fogo, Cerro Negro and Erebus; a pyroclastic flow at Lascar; and open vent systems at Etna and Stromboli. Automated near real-time analysis of AVHRR data could be achieved at existing, or cheap to install, receiving stations, offering a supplement to conventional monitoring methods. Received: 21 January 1997 / Accepted: 3 April 1997     

从辽宁东、西部地质对比论郯庐断裂的平移运动

辽宁东、西部地质上诸多差异并非是原地升降运动造成的，而是二个异地岩块经郯庐断裂大规模左旋平移运动迁移到一起的结果。辽东半岛原曾与鲁西－徐淮地区处于相同的古纬度。郯庐断裂北延的主干断裂应是抚顺－敦化断裂，它在辽宁境内是地层区划的重要界线。郯庐断裂在太古宙末期即已出现，曾多次变换其平移方向，最近一次大规模左行平移活动的高峰期是在晚侏罗世晚期－早白垩世，结束于孙家湾组或泉头组堆积之前。     

Numerical modeling for analyzing thermal surface anomalies induced by underground coal fires

Coal seams burning underneath the surface are recognized all over the world and have drawn increasing public attention in the past years. Frequently, such fires are analyzed by detecting anomalies like increased exhaust gas concentrations and soil temperatures at the surface. A proper analysis presumes the understanding of involved processes, which determine the spatial distribution and dynamic behavior of the anomalies.In this paper, we explain the relevance of mechanical and energy transport processes with respect to the occurrence of temperature anomalies at the surface. Two approaches are presented, aiming to obtain insight into the underground coal fire situation: In-situ temperature mapping and numerical simulation. In 2000 to 2005, annual temperature mapping in the Wuda (Inner Mongolia, PR China) coal fire area showed that most thermal anomalies on the surface are closely related to fractures, where hot exhaust gases from the coal fire are released. Those fractures develop due to rock mechanical failure after volume reduction in the seams. The measured signals at the surface are therefore strongly affected by mechanical processes.More insight into causes and effects of involved energy transport processes is obtained by numerical simulation of the dynamic behavior of coal fires. Simulations show the inter-relation between release and transport of thermal energy in and around underground coal fires. Our simulation results show a time delay between the coal fire propagation and the observed appearance of the surface temperature signal. Additionally, the overall energy flux away from the burning coal seam into the surrounding bedrock is about 30-times higher than the flux through the surface. This is of particular importance for an estimation of the energy released based on surface temperature measurements. Finally, the simulation results also prove that a fire propagation rate estimated from the interpretation of surface anomalies can differ from the actual rate in the seam.     

Analysis of drivers governing temporal salinity and temperature variations in groundwater discharge from Altug Submarine Karst Cave (Kas-Turkey)

Salinity and temperature variations in groundwater discharge from the Altug submarine karst cave have been observed at 28 m below sea level for every 10 min between November 2004 and August 2005 to determine the drivers that govern the salinization. Comparisons between temporal trends of salinity and temperature with those of precipitation, air pressure, sea level and wind velocity revealed an apparent dominance of precipitation regime on the salinity and temperature variations. Spectral analyses applied to observations showed that the air pressure and sea level oscillations are affected by sun and moon tides which do not have an appreciable impact on the salinity and temperature variations. Annual rate of salinization in Altug cave seems inversely related to the inland groundwater head so that the maximum and minimum fresh water contributions occur at mid-spring and late-summer, respectively.     

Estimated intensity needed for sampling flatfish assemblages in reference areas of tidal mud flats systems may be disproportionately costly and deleterious

Beam trawl surveys were carried out in a tidal stream system of the German Wadden Sea on two to three successive days of comparable weather conditions in three summers. The variability in time and space detected for plaice (Pleuronectes platessa), flounder (Platichthys flesus), dab (Limanda limanda), sole (Solea solea) and lemon sole (Microstomus kitt) was considerable even for species with a very high abundance. Other flatfish species such as turbot (Scophthalmus maximus) and brill (Scophthalmus rhombus) occurred only occasionally in the catches. Sampling effort calculated to detect a 50 or 20% difference between the surveys caused by immigration, emigration or mortality appears to be disproportionate. It is argued that such a major sampling effort of reference areas in tidal mud flat systems is likely to influence the results, to harm the environment, and to be very expensive.     

Vertical and seasonal differences in biogenic silica dissolution in natural seawater in Suruga Bay, Japan: Effects of temperature and organic matter

Vertical and seasonal characteristics of biogenic silica (BSi) dissolution in seawater were investigated by multiple dissolution experiments using seawater collected from surface and mesopelagic layers in Suruga Bay during the period 2002–2004. The dissolution rate coefficients calculated based on temporal changes of BSi concentration varied with the season of sample collection. They ranged from 0.023–0.057 day^− 1 for surface samples and 0.0018–0.0025 day^− 1 for mesopelagic samples for temperatures approaching in situ conditions. Experiments at various temperatures confirmed that BSi dissolution depends on temperature in natural seawater. Dissolution rate coefficient (day^− 1) of BSi correlated significantly with temperature (°C), and Q₁₀ was 2.6. Addition of bioavailable organic matter to low-bioactivity seawater enhanced the protease activity and abundance of bacteria, and increased BSi dissolution rate by a factor of 1.4–2.0. There is clear evidence that BSi dissolution is accelerated by bacterial activity and potentially limited by bioavailable organic matter in natural seawater. Dissolution rates and total decreases of BSi concentration were lower during experiments using mesopelagic samples than in those using surface samples. This suggests that dissolution of BSi varies with depth and that BSi in the mesopelagic water is more resistant to the dissolution than that in the surface water. This lower dissolution rate was caused by lower temperature and lower bacterial activity due to less bioavailable organic matter in mesopelagic water. Our results provide a mechanistic understanding of variations in silica cycling within the seasonally and vertically differing marine environment.     

温度对南美白对虾的影响

探讨了温度对南美白对虾(Penaeus vannamei)的影响。结果表明，在9～22℃范围内。南美白对虾能够适应逐渐降温和逐渐升温，存活率分别达100％和97．92％。降温后。10℃充氧密封24h，对其生存无影响，存活率100％。此后逐渐升温至22℃，并在22-23℃中暂养3d,对虾存活率95％。