长江中游高位砾石层的磁性特征与物源分析

在长江中游分布着一些高位的砾石层,尤其是在宜昌与武汉的阳逻附近。为了探讨这些砾石层的磁性特征及物质来源,对它们进行了磁性特征研究,结果表明:1不同砾石层剖面磁性物质的含量明显不同,其中云池砾石层磁性物质的含量最高,善溪窑、红花套、白洋渡砾石层次之,阳逻砾石层含量最低。2SIRM/χ和F300值显示,长江中游砾石层磁性矿物类型主要是磁铁矿等亚铁磁性矿物,其中阳逻砾石层不完全反铁磁性矿物含量比例比其他砾石层高。3χARM/χ、χARM/SIRM、χfd值表明,白洋渡、红花套及善溪窑砾石层的磁性矿物中以较粗的磁性颗粒为主,而云池和李家院的磁性矿物颗粒都较细,武汉阳逻砾石层的磁性颗粒以单畴、超顺磁颗粒为主。4宜昌附近的善溪窑、云池、白洋渡、红花套砾石层的磁性特征与长江现代沉积物的特征接近,指示其物质主要来自于长江沉积物;而阳逻砾石层的磁性特征却与江汉平原周边河流的现代沉积物磁性特征有些类似,结合野外砾石层岩性特征,认为阳逻砾石层是长江、汉江与江汉平原周边河流共同作用的产物。     

淮南潘三矿区地温分布规律及其影响因素分析

潘三矿位于淮南煤田潘谢矿区东区,潘集背斜西段南翼。根据对矿区内15个测温钻孔的研究,发现该矿存在着明显的地温异常。在纵向上,表现为地温温度随深度的增加而增加,并呈现良好的线性趋势,具有传导型增温特点;在横向上,受构造控制作用和上覆松散层厚度影响,靠近背斜轴部和松散层较厚的地方,地温梯度相对较高;岩浆岩的侵入和地下热水的运移也对地温有一定的影响。总体上,研究区地温受构造控制作用明显。该研究对矿区的热害预防提供了基础技术参数。     

Development and mechanical strength properties of a new lightweight soil

The time-dependent settlement of soft soil poses serious maintenance problems to developments along coastal and riverside areas that encounter thick, soft soil deposits. To overcome this problem, therefore, a lightweight material called Air-Trapped Soil (ATS) was developed. ATS was prepared using sand produced at a factory, so its quality is highly stable. To determine the characteristics of the developed ATSs, a series of unconfined compressive and split tensile tests were conducted, and the compressive and tensile strength characteristics of the lightweight ATSs of various combinations of cement-air bubble-sand were determined. In addition, the relationship between the compressive and tensile strengths was determined. This result shows that the mechanical strength characteristics of the ATS significantly depend on the quantity of air bubbles in the ATSs.     

山东省采煤塌陷地综合治理实践与思考

山东省煤炭资源丰富,长期的煤炭开采形成了大量采煤塌陷地,引发耕地破坏、基础设施受损、城市发展受限等一系列问题。截至2020年底,山东省累计形成采煤塌陷地9.20万hm~2,经过30多年的治理实践,共治理采煤塌陷地7.60万hm~2。本文通过梳理山东省采煤塌陷地综合治理相关文件和案例,总结了山东省采煤塌陷地综合治理政策实践和技术模式实践成果,划分了治理技术模式发展阶段,指出了山东省采煤塌陷地综合治理面临的问题,并提出了相应对策与措施。     

Radiocesium reaction with illite and organic matter in marine sediment

The mineralogical effect on the (137)Cs reaction with marine sediment has not been systematically studied yet, even though illite has been known to adsorb Cs preferentially on its frayed edge sites in a low Cs concentration. Ninety-three marine sediment samples were collected near Yangnam, Korea for quantitative X-ray-diffraction (XRD), gamma-ray, and total organic carbon (TOC) analysis. Illite content was in the range of 0-23 wt.% and those of (137)Cs and TOC were minimum detectable activity (MDA) approximately 7.19 Bq/kg-dry and approximately 3.32%, respectively. The illite content in the marine sediment showed a good relationship with the (137)Cs content (R(2)=0.69), but with an increase in the illite content, the relationship became less linear. This trend can be clearly shown in two groups of samples with different size fractions (< and >5Mdvarphi). For the samples of larger particle sizes (low contents of illite), the relationship is linear, but for the samples of the smaller particle sizes (high illite content) it is less linear with a decreased slope, indicating that increase in illite content does not significantly contribute to the fixation of (137)Cs in marine sediment. Rather, the TOC has a more linear relationship with (137)Cs content with no slope change in all particle size ranges. This may indicate that humic materials in marine sediment block the access of (137)Cs to the frayed edge site and reduces the adsorption of (137)Cs on illite and that the organic materials in marine sediment play more important roles in adsorbing Cs than illite.     

Intercomparison of precipitation simulated by regional climate models over East Asia in 1997 and 1998

Regional climate simulations in Asia from May 1997 to August 1998 were performed using the Seoul National University regional climate model （SNURCM） and Iowa State University regional climate model （ALT.MM5/LSM）, which were developed by coupling the NCAR/Land Surface Model （LSM） and the Mesoscale Model （MM5）. However, for physical processes of precipitation, the SNURCM used the Grell scheme for the convective parameterization scheme （CPS） and the simple ice scheme for the explicit moisture scheme （EMS）, while the ALT.MM5/LSM used the Betts-Miller scheme for CPS and the mixed phase scheme for EMS.
The simulated precipitation patterns and amounts over East Asia for the extreme climatic summer in 1997 （relative drought conditions） and 1998 （relative flood conditions） were especially focused upon. The ALT.MM5/LSM simulated more precipitation than was observed in 1997 due to more moisture and cloud water in the lower levels, despite weak upward motion. In the SNURCM, strong upward motion resulted in more precipitation than that was observed in 1998, with more moisture and cloud water in the middle levels. In the ALT.MM5/LSM, weak upward motion, unchanged moisture in the lower troposphere, and the decrease in latent heat flux at the surface increased convective precipitation only by 3% for the 1998 summer event. In the SNURCM, strong upward motion, the increase in moisture in the lower troposphere, and the increase in latent heat flux at the surface increased convective precipitation by 48% for the summer of 1998. The main differences between both simulations were moisture availability and horizontal momentum transport in the lower troposphere, which were also strongly influenced by large-scale forcing.     

The accumulation of radiocesium in coarse marine sediment: effects of mineralogy and organic matter

The controlling factors affecting the accumulation of (137)Cs in marine sediment have not been investigated in detail, especially in coarse grained sediment. Eighty eight coarse marine sediment samples near Wuljin, Korea, were characterized by quantitative X-ray-diffraction (XRD), gamma-ray, and total organic carbon (TOC) analysis. Those factors were then compared. The grain size was in the range of -0.48 to 3.6Mdphi corresponding to sand grains. TOC content was in the range of 0.06-1.75%, and the concentration of (137)Cs was 相似文献   

Why did the copepod Calanus sinicus increase during the 1990s in the Yellow Sea?

Recent field and retrospective data were combined to investigate variations from 1984 to 1998 in the spring abundance of dominant copepods in the Yellow Sea. A calanoid copepod, Calanus sinicus, was chosen to assess the long-term changes in abundance associated with temperature, salinity, chlorophyll-a and predator abundance. Average anomalies of sea surface temperature (SST), salinity, and the abundance of C. sinicus were positive in the 1990s and negative in the 1980s. The average abundances of C. sinicus in the study area in the 1990s were also significantly higher than those in the 1980s (p<0.01). Catches of the anchovy Engraulis japonicus, a predator of C. sinicus, showed a decreasing trend during the study period. The higher abundances of C. sinicus in the 1990s may have been affected by an increase in water temperature and a decrease in predators, without distinctive changes in chlorophyll-a concentrations during the study period.     

The Annual Gametogenesis of the Mussel,Mytilus unguiculatus (coruscus) (Valenciennes, 1858), Occurring in the Shallow Subtidal of Ulleungdo Island in Korea

Ocean Science Journal - The mussel Mytilus unguiculatus (coruscus) (Valenciennes, 1858) occurs at high density on the shallow subtidal hard bottom of Ulleungdo Island off the east coast of Korea,...     

中国大陆及邻GRACE卫星重力变化研究

探讨如何运用GRACE数据进行重力变化的计算和分析.对GRACE重力场位系数的最大阶次选取进行了分析,并利用月卫星重力场模型计算了中国大陆及邻区的重力变化,通过平均半径为800km的高斯平滑,得出了合理的重力变化结果.