Extinction of H ii regions in the Large Magellanic Cloud

The extinction properties of H  ii regions in the Large Magellanic Cloud are investigated using radio continuum data obtained from the Molonglo Observatory Synthesis Telescope, digitized and calibrated Hα data and published Balmer decrement measurements. The resulting extinction–colour excess diagram suggests that (1) most H  ii regions in the Magellanic Clouds have similar extinction properties to the Galactic ones, (2) all imaginable gas/dust configurations are possible, (3) the extinction of some highly reddened H  ii region cores originates externally in cocoon shells.   The puzzle of different extinction–colour excess ratios of Galactic and extragalactic H  ii regions is explained as being due to the different populations of observed samples rather than any intrinsic differences. The extinction of the observed Galactic H  ii regions produced by foreground dust overwhelms the internal extinction, while the situation in the observed extragalactic H  ii regions is just the opposite.     

Starlight polarization and CO observations towards the Lupus clouds

We performed an observational study of the dark filaments Lupus 1 and Lupus 4 using both polarimetric observations of 190 stars and a sample of 72 ¹²CO profiles towards these clouds. We have estimated lower limits to the distances of Lupus 1 and Lupus 4 (≳ 140 and ≳ 125 pc, respectively). The observational strategy of the survey allows us to compare the projected magnetic field in an extended area around each cloud with the magnetic field direction observed to prevail along the clouds. Lupus 4 could have collapsed along the magnetic field lines, while in Lupus 1 the magnetic field appears to be less ordered, having the major axis of the filaments parallel to the large-scale projected magnetic field. These differences would imply that both filaments have different pattern evolutions. From the CO observations we have probed the velocity fields of the filaments and the spatial extension of the molecular gas with respect to the dust.     

气候因子对内蒙古沙尘暴频率的影响

利用内蒙古中西部地区40年(1961～2000年)的气象资料、沙尘暴资料和气候资料,讨论了内蒙古中西部地区沙尘暴频率变化趋势和气候动力因子对沙尘暴频率的影响.结果显示:近40年期间,内蒙古中西部地区沙尘暴日数有明显的减少趋势,沙尘暴频率总体上减少的主要原因是影响沙尘暴频率趋势的气候动力因子,也就是代表冷空气活动的气候因子周期变化所致.影响内蒙古中西部地区沙尘暴频率时间分布变化的气候主导因子是:大风日数、北半球极涡面积指数、亚洲北半球极涡强度指数等代表冷空气活动的气候动力因子.     

Cosmic Ray-Induced Polycondensate Hydrocarbons in Giant Molecular Clouds

Astrophysical and cosmochemical data show that many kinds of hydrocarbons are widespread in space, including giant molecular clouds, diffuse interstellar medium, comets, interplanetary dust particles, and carbonaceous meteorites. Here an effort is made to show the close relation between high-molecular weight hydrocarbons observed in space and existing on Earth. Results of astrochemical modelling of dust grains in dense collapsing cores of giant molecular clouds are also presented. They show that about 10% of the total abundance of dust grains may be the result of aliphatic hydrocarbons. This dust serves as initial material for comets, formed in protosolar nebula. The problem of survival of cometary organics during impact onto the Earth is discussed, and it is shown that the so-called soft-landing comet hypothesis may explain the accumulation of complex hydrocarbons on the Earth's surface. We conclude that a significant fraction of terrestrial prebiotic petroleum was delivered by extraterrestrial matter.     

铁质宇宙尘中的有机分子的发现

于1983年5－7月，利用向阳红16号考察船在太平洋7—11°N，167－178°W海域进行锰结核调查，从深海沉积物中分离出大量字苗尘（或称宇宙球粒）。此后对宇宙尘进行了全面研究，取得一定进展。最近，又利用激光拉曼分子探针测定了铁质宇宙尘中的分子组成。结果表明，铁质字宙尘中除了含有Fe－Fe，Fe3＋O，Fe－Ni，Al－O，Fe－Obr－Si和Si-Onb分子外，还含有较丰富的C－H－O和C－H－S－O有机分子，无定形碳C=C和C=C，CH2，CH3和挥发分子CO2，H2O，OH－，H2S，SO2等。这些成份与刍星尘埃的分子成分相一致。这一结果对于深入研究行星际尘埃微粒的起源以及探索生命物质的起源都具有重要意义。     

海上油田油轮外输系统优化分析

对海上油田油轮外输系统进行了分析 ,建立了系统优化的数学模型。选用模矢搜索法、单纯形算法和模拟退火算法三种优化方法进行了计算 ,得出在对某些非线性问题进行优化时 ,利用模拟退火算法和直接最优化方法 (如单纯形法 )相结合 ,既能保证得到全局最优解 ,又能减少计算时间。通过实例计算 ,得出油轮外输系统适用于离岸距离较远、产量较小的油田 ,其外输费用随离岸距离的增加变化非常小 ,但随油田产量的增加而增加较大     

厦门东屿白骨壤林土壤甲烷的产生量、氧化量、传输率与库量

测定了厦门东屿白骨壤（Avicennia marina）林土壤的甲烷产生量及其在土壤中的氧化、传输与库量．土壤甲烷产生量基本上呈内滩>中滩>外滩的滩面变化趋势，季节变化趋势为秋、冬季低于春、夏季，与甲烷氧化量的时空变化模式一致，与甲烷库量的时空变化模式也基本相同．所有季节所有滩面土壤甲烷产生量、氧化量、库量的平均值分别为9.11mg/(m     

黑河中游现代孢粉传播过程研究

在位于河西走廊的黑河中游地区选取8个河流沉积样品和7个表土样品进行孢粉分析,通过其孢粉百分含量分别探讨河流与风力搬运对孢粉传播的影响。结果表明：风力对孢粉具有较强的搬运能力,能够将区域外或上游山地植被孢粉搬运至中游地区,但其对当地孢粉贡献较小,一般低于10%;河流搬运孢粉的能力大于风力,能够将上游山地植被孢粉大量的搬运至研究区,外来孢粉含量最高可达39.4%,成为孢粉谱的重要成分。表土孢粉组合能够较好的反映研究区现代植被的分布情况;河床沉积物孢粉组合反映的是上游山地植被和研究区植被混合状况。     

跨省山区陆路交通网络可达性评价——以乌蒙山区为例

基于交通地理学的基本理论和GIS技术,构建跨省山区空间阻隔可达性模型,并以跨滇川黔三省的乌蒙山区42个县(市、区)为研究个案进行分析。结果表明:1区内可达性表现出显著的中心外围递减的圈层空间格局特征;2区外可达性表现出显著的东西分异格局特征;3乌蒙山区综合交通可达性整体水平较低,中心城镇可达性水平相对较好,整体差异不大,可达性水平表现出明显的低均衡性特征。综合交通可达性具体表现出"核心-外围"圈层分异结构特征和东部与西部分异结构特征。建议从跨省区域交通网络合作、快速交通网络大通道、区域交通网络联通率、全域交通运输方式的变革等方面重视跨省山区交通网络建设。     

Infrared appearance of dynamical models for circumstellar dust shells around long-period variables

Synthetic brightness profiles resulting from consistent dynamical models for circumstellar dust shells around long-period variables are presented and discussed with respect to a corresponding observation of IRC +10216.