Evolutive characteristics of aromatics under high pressure and temperature of deep lithosphere

Pyrolysis of lignite in closed systems was conducted at temperatures from 400 to 700℃ and pressure from 1 to 3 GPa in order to investigate the evolutive characteristics of aromatics and the effects of pressure and temperature on the maturation of organic matter under the extreme conditions. The total yield of liquid hydrocarbons decreased with increasing pressure and the aromatics shows more mature with increasing temperature at a given pressure. The data indicate that high pressure significantly suppresses the thermal evolution of geological organic matter especially at lower temperature, but favors the cyclization, polymerization and aromatization of pyrolysate. The pressure effect on maturation of organic matter is nonlinear. Therefore, it can be inferred that sediment organic-matters in the subducted slab could be retained in the deep lithosphere, and the results are also significant for understanding the accumulation and preservation of petroleum in deep reservoirs.     

Analyses and numerical modeling of a polar low over the Japan Sea on 19 December 2003

A meso-α-scale polar low was observed over the Japan Sea on 19 December 2003. It initialed around 11 UTC over the northwestern part of the Japan Sea within a synoptic-scale parent low under the influence of baroclinic environment and disappeared over the eastern edge of Japan Islands with a lifetime of about 20 h. It is of interest that this polar low had “concentric eye-walls” and “warm core” structure at its mature stage. The evolutionary process and spatial structure of this polar low were investigated by using almost all available observational data, including the Geostationary Operational Environmental Satellite (GOES)-9, the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery, the Final Analyses (FNL) data issued by National Centers for Environmental Prediction (NCEP), the surface observational data and the 9-station sounding data of Japan Islands. In order to study its development mechanism, a 24-h numerical simulation using the version 4.4 of the Regional Atmospheric Modeling System (RAMS) starting from 12 UTC 19 December 2003 with an 8 km × 8 km resolution was performed. It is shown that the RAMS model reproduced the main features of the polar low reasonably well. The vorticity budget analyses indicate that the stretching term is the major contributor for the vorticity increase of the polar low. The baroclinic background seems to play significant role for the initial development of this polar low. However, the effect of the diabatic heating for its later development is also significant.     

全球大气位势高度场气候变率的球函数分析

为了研究全球大气位势高度场的气候变率, 利用NCEP/NCAR再分析资料, 按照距平高度场平均强度指数 (I_a) 分析发现, 半球距平高度场强度呈年单周振荡, 冬大夏小, 冬季随高度单调增大, 夏季有弱高、低值中心出现, 而北、南半球的差异明显表现在季节变化上; 进一步根据半球大气位势高度距平场球函数谱低维、低阶的基本特征, 将半球环流异常分为半球均匀异常 ( H ′₀₀)、纬向均匀异常 ( H ′₀)、超长波尺度异常 ( H ′_ul) 和长波尺度异常 ( H ′_l) 4种类型, 用波数域0≤m, k≤6上的球函数系数资料求得它们的方差贡献, 给出了4类异常的方差贡献随高度、季节变化的规律以及它们的半球际差异。由此得到异常环流球函数谱结构的总体特征为:对流、平流层之间存在明显变化。从对流层进入平流层, 一般由超长波异常为主转为纬向均匀异常为主 (冬半球) 或半球均匀为主 (夏半球); 半球均匀异常在对流层中不重要, 长波尺度异常在平流层中不重要, 它们拟合异常方差一般均小于10%; 北、南半球最大差异表现在冬季平流层R′₀₀和冬、夏季对流层R′₀南半球大于北半球, 冬、夏季对流层R′_l北半球大于南半球。     

Effects of blue light on gametophyte development of Laminaria japonica (Laminariales, Phaeophyta)

Laminaria gametophyte was greatly influenced by light in its growth and development. Using light-emitting diodes (LED) as blue and red light sources, we analyzed the light effect on gametophytes development ofLaminaria japonica Aresch. The gametophytes were obtained from zoospores collected in April, May, July, 2003 and September, 2004. We found that the growth of gametophytes was stimulated by increasing intensity of blue light (BL) and red light (RL) illumination, of which BL was obviously stronger than that of RL. The fertilization of gametophytes depended largely on BL, and only sufficient BL illumination could take the reproductive effect. In addition, we noticed that there was a significant difference in light responses for gametophytes developed from zoospore collected in different times. For zoospores released in April, under BL₁ (73.90 μmol photons/m·s), the unicellular female gametophytes and multi-cellular male gametophytes produced eggs and sperms respectively, and further developed towards sporophytes. However, for gametophytes developed in May, July or September, they became multi-cellular and never formed oogonia or antheridia. It is believed that theLaminaria sporangium maturation stage could affect the gametophytes reaction to BL under laboratory culture conditions. Therefore, cryptochrome- or phototropin-like BL photoreceptors is probably involved in BL-induced development ofLaminaria gametophytes. This research was supported by the NSFC (No.40376049) and Japan Society for the Promotion of Science (The Invitation Fellowship for Research in Japan 2002).     

Observation of female gamete (Carpogonia) germination of Porphyra yezoensis and P. oligospermatangia

Several papers have reported that part or whole leafy thallus seemingly consisting of zygotospores can give rise to both blades and conchocelis in the same culture ofPorphyra. Study on samples of wild and cultivatedPorphyra yezoensis andP. oligospermatangia were conducted to clarify the origination of the young blades in the culture. It is confirmed that single cells on the blade of both species, which normally intermixed with zygotospores, germinated into young blades. TEM and SEM observation has shown that the single cells ofPorphyra yezoensis had typical features of female gamete (carpogonia) but archeospore. Therefore, the female gametes are responsible in developing leafy thalli. This project was sponsored by the NSFC (No. C-0205-05-39770593)     

Middle Yangtze sea-basin over Paleozoic-Mesozoic transition

On the centimeter scale of lithologic change, we conduct poly-statistic analysis on the sedimentary behavior and dynamic features of the stratigraphic sequence from upper Dalong formation to lower Daye formation, which across the Permian-Triassic boundary in East Hubei. From the perspective of stochastically dynamic system, the depositional process of upper Dalong formation can be regarded as a stable Markovian process with weakly stratigraphie correlation and randomly lithologic alteration. Compared to it, the depositional process of lower Daye formation was unstable Markovian process with much closer stratigraphic correlation and ordered lithologic change. As for the replacement style of the sedimental cycle, the former was chaotic, while the latter was periodical. Otherwise, although the overall depositional process of the two formations was continuous, their dynamic characteristics were obviously different. So this P-T sedimental boundary can also be regarded as a dynamic limit. It was a kind of depositional reaction in response to a catastrophic alteration when the geological environment was in continuous change but came over a certain threshold state.     

Study on basement structures of the northeast Pamirs

1 Geologic setting and layout of the DSS observation network In the studied area there are three major tectonic units, which are referred to as Tianshan fold system, Tarim basin and West Kunlun fold system (Bureau of Geology and Mineral Resources of Xinjiang Uygur Autonomous Region, 1993). The Tianshan fold system is a polycyclic geosyncline on the north edge of Tarim basin, and an orogenic zone resulting from collision and convergence between Tarim block and the Junggar-North Tianshan…     

Temperature and methane records over the last 2 ka in Dasuopu ice core

High resolution δ¹⁸O and methane records over the last 2ka have been reconstructed from Dasuopu ice core recovered from the Himalayas. Analysis shows that the δ¹⁸O record correlates well with the Northern Hemispheric temperature, Dunde ice core record, and with temperature record in eastern China. The warming trend detected in δ¹⁸O record from the last century is similar to that during the Medieval warm period. There is a dramatic increasing in methane concentration in the Dasuopu ice core, which reached 1031 nmol ⋅ mol^-1 in 1997. Moreover, methane concentration in the Dasuopu ice core is about 15%-20% higher than that in Antarctica and Greenland. There is a positive correlation between methane concentration and δ¹⁸O in Dasuopu ice core.     

强对流(冰雹)云中水凝物的积累和云水的消耗

在冰雹云中过冷水的累积对冰雹增长起重要作用。文中回顾了水凝物累积和过冷水消耗机制中的不确定性 ,利用三维Euler强对流云模式和三维Lagrange粒子群运行增长模式 ,重新研究了对流云中水凝物粒子的累积机制和过冷水的消耗图像 ,得出以下结果 :(1)强对流 (冰雹 )云具有翻滚式对流流场 ,流场的性质决定云中存在着一个动力吸引区 ,它处于主上升气流区旁侧水平气流近于零的区域 ,粒子在增长运行中向这里集中 ,造成水凝物的累积 ;(2 )这种粒子的集中和水凝物的累积 ,是流场动力特征和粒子增长行为相互作用的表现 ;(3)粒子的集中和水凝物的累积是动态循环式的 ,而不是静态平衡式的 ,粒子可以进入吸引区 ,也可以吹离吸引区 ,在进入和吹离的循环中动态地形成了集中和累积 ,累积可以发生在主上升气流上方 ,也可以延伸到其下方 ;(4)粒子的集中和水凝物的累积是受流场和粒子运动的动力过程控制的 ,而累积粒子是液相雨滴 ,或是固相霰粒、雪团和冰雹是受降水发展过程属液相或固相占优势来决定的 ;(5 )云水场中云水量 ,只在大粒子的集中区才被显著消耗 ;而在区外的云水量消耗不显著 ;(6 )对于云水含量高达 6 g/kg的云水场 ,播撒粒子浓度达到 10 0个 /m3 时 ,在考虑消耗时 ,已不能增长成直径大于 1cm的冰雹。