南海红树林内生真菌1356~#代谢产物的研究

从南海红树林内生真菌1356#分离出两种鞘胺醇(A,B)和三种环二肽(C,D,E)?它们的结构通过IR,MS,1D NMR和2D NMR谱推导出来?(3＇E,4E)-1-(-D-吡喃葡萄糖基-3-羟基-2-(2＇-羟基十八碳酰基)氨基-10-甲基-3＇,4,9-十八碳三烯(A)是一种新的鞘胺醇甙?     

水合物和冷泉的地质微生物和生物地球化学特征

这个专题研究是在2001年美国加利福尼亚旧金山由美国地质协会召开的秋季会议上提出的。研究目的是总结所有扩展研究区内水合物和冷泉的地质微生物和生物地球化学特征。围绕这个问题，笔者结合了最新的研究资料；因此，文中大部分内容之前还未出版过，同时也介绍了一些新项目的开展情况。     

大西洋中脊含金属沉积物中铀的富集

大西洋中脊含金属沉积物中铀的富集Ｒ．Ａ．Ｍｉｌｌｓ等在整个洋中脊体系观察到的富金属沉积物提供了区域性寻找某些元素的重要线索。考虑到全球平衡，这种富金属沉积物是十分重要的。７０年代在大西洋中脊２６°Ｎ横贯大西洋地质大断裂地区（ＴＡＧ区）发现了富金属沉积...     

Distribution of winter-spring snow over the Tibetan Plateau and its relationship with summer precipitation in Yangtze River

The distribution of winter-spring snow cover over the Tibetan Plateau(TP) and its relationship with summer precipitation in the middle and lower reaches of Yangtze River Valley(MLYRV) during 2003–2013 have been investigated with the moderate-resolution imaging spectrometer(MODIS) Terra data(MOD10A2) and precipitation observations. Results show that snow cover percentage(SCP) remains approximately 20% in winter and spring then tails off to below 5% with warmer temperature and snow melt in summer. The lower and highest percentages present a declining tendency while the middle SCP exhibits an opposite variation. The maximum value appears from the middle of October to March and the minimum emerges from July to August. The annual and winter-spring SCPs present a decreasing tendency. Snow cover is mainly situated in the periphery of the plateau and mountainous regions, and less snow in the interior of the plateau, basin and valley areas in view of snow cover frequency(SCF) over the TP. Whatever annual or winter-spring snow cover, they all have remarkable declining tendency during 2003–2013, and annual snow cover presents a decreasing trend in the interior of the TP and increasing trend in the periphery of the TP. The multi-year averaged eight-day SCP is negatively related to mean precipitation in the MLYRV. Spring SCP is negatively related to summer precipitation while winter SCP is positively related to summer precipitation in most parts of the MLYRV. Hence, the influence of winter snow cover on precipitation is much more significant than that in spring on the basis of correlation analysis. The oscillation of SCF from southeast to northwest over the TP corresponds well to the beginning, development and cessation of the rain belt in eastern China.     

Titan's stratospheric temperature asymmetry: a radiative origin?

During the 1981 Voyager encounter, Titan's stratosphere exhibited a large thermal asymmetry, with high northern latitudes being colder than comparable southern latitudes. Given the short radiative time constant, this asymmetry would not be expected at the season of the Voyager observations (spring equinox), if the infrared and solar opacity sources were distributed symmetrically. We have investigated the radiative budget of Titan's stratosphere, using two selections of Voyager IRIS spectra recorded at symmetric northern and southern latitudes. In the region 0.1-1 mbar, temperatures are 7 K colder at 50 degrees N than at 53 degrees S and the difference reaches approximately 13 K at 5 mbar. On the other hand, the northern region is strongly enriched in nitriles and hydrocarbons, and the haze optical depth derived from the continuum emission between 8 and 15 micrometers is twice as large as in the south. Cooling rate profiles have been computed at the two locations, using the gas and haze abundances derived from the IRIS measurements. We find that, despite lower temperatures, the cooling rate profiles in the pressure range 0.15-5 mbar are 20 to 40% larger in the north than in the south, because of the enhanced concentrations of infrared radiators. Because the northern hemisphere appears darker than the southern one in the Voyager images, enhanced solar heating is also expected to take place at 50 degrees N. Solar heating rate profiles have been calculated, with two different assumptions on the origin of the hemispheric asymmetry. In the most likely case where it results from a variation in the absorbance of the haze material, the heating rates are found to be 12-15% larger at the northern location than at the southern one, a smaller increase than that in the cooling rates. If the lower albedo in the north results from an increase in the particle number density, a 55 to 75% difference is found for the pressure range 0.15-5 mbar, thus larger than that calculated for the cooling rates. Considering the uncertainties in the haze model, dynamical heat transport may significantly contribute to the meridional temperature gradients observed in the stratosphere. On the other hand, the latitudinal variation in gas and haze composition may be sufficient to explain the entire temperature asymmetry observed, without invoking a lag in the thermal response of the atmosphere due to dynamical inertia.     

行星边界层模式中中性层结条件下的E-ε-l湍流闭合方案

由标准Ｅ－ε模式得到的行星边界层厚度似乎太大，之所以如此，可归因于湍流动能（Ｅ）的耗散率（ε）方程，特别是方程中耗散生成和损失项的参数化方法。在大气边界层的模拟研究中，我们认为谱能储存部分的谱串级输送过程必须作为耗散生成的一部分加以考虑，并用特征长度ｌε表示。与标准模式一样，耗散局地生成和损失作用之间的“平衡”的不稳定性，当作正比于Ｅ２／Ｅ的量处理。文中提出Ｅ－ε－ｌ湍流闭合方案，同时包含了混和长度ｌｍ和ｌε。虽然ε仍决定Ｅ方程中的耗散率，但其重要性减弱了。     

南极海胆体内的共栖纤毛虫原生动物

研究报道了采自南极威德尔海区海胆体内的三种内共栖纤毛虫,分别隶属于寡膜纲盾纤目和多膜纲寡毛目。文中对所涉各种属的活体形态学特征、纤毛图式和银线系作了研究报道     

Settlement network development policy and urbanisation in Hungary in the 20th century

"The paper brings out the role of political economy in influencing the process of urbanisation and [the] structure of settlement network. This is demonstrated through an empirical study of Hungary during the twentieth century. Three phases get easily distinguished: pre-1949 or the period of changes in the state boundaries; 1949-89 or the period of state socialism; and post-1989 or the period of institutional reform. An interesting finding is that there was a bias in favour of large cities and county seats in allocation of development funds under all the regimes."     

新仙女木期间西赤道太平洋的海面温度

新仙女木期间西赤道太平洋的海面温度ＲｏｂｅｒｔＣ．Ｔｈｕｎｅｌ等末次冰消期不是从一种气候状态到另一种气候状态的平稳过渡期，而是包括有许多阶段。根据对海洋δ１８Ｏ记录的研究，Ｄｕｐｌｅｓｓｙ等（１９８１）提出了两阶段的冰消模式，即一个短时气候稳定期隔开...