黔北务川—正安—道真地区下二叠统大竹园组和梁山组孢粉学研究

文中材料采自黔北务川—正安—道真地区下二叠统大竹园组和梁山组。大竹园组孢粉化石类型单调,保存较差;而梁山组孢粉化石丰富,保存良好。孢粉组合特征为:(1)大竹园组包含丰富的Calamospora和Florinites及少量Torispora verrucosa,Gulisporites,Alisporites,Hamiapollenites和Striatopodocarpites,这一孢粉组合主要出现在上石炭统至下二叠统。按照大竹园组层位和孢粉化石特征,其地质时代应为早二叠世Asselian期—Artinskian期(相当于紫松期—隆林期)。(2)梁山组中可建立孢粉组合Laevigatosporites vulgaris-Gulisporites-Florinites ovalis,共计发现孢粉化石34属49种,其中蕨类植物孢子含量为51.6％～56.1％,裸子植物花粉含量为43.9％～48.4％。与大竹园组沉积时期相比,这一时期植被极为繁盛。根据孢粉组合特征,梁山组地质时代可能为早二叠世隆林期,即Kungurian期。     

沉积岩平行层面与垂直层面方向热导率与孔隙连通性之间的关系

根据对渤海湾盆地沾化凹陷泥质岩、粉砂岩、砂岩和白云岩平行层面与垂直层面方向热导率差异及孔隙连通性差异特征的研究,探讨了沉积岩平行层面与垂直层面方向热导率与孔隙连通性之间的关系。热导率实验结果表明:沾化凹陷泥质岩、粉砂岩和砂岩的平行层面方向热导率大于垂直层面方向热导率;白云岩的平行层面方向热导率小于垂直层面方向热导率。沉积岩平行层面与垂直层面方向热导率差异和孔隙连通性差异之间具有正相关性。孔隙特征分析结果表明:孔隙连通性较好方向,热导率也较高;孔隙连通性较差的的方向,热导率也较低。     

沁水盆地煤层气成藏主控因素与成藏模式分析

沁水盆地石炭-二叠系煤层厚度大、分布稳定、演化程度高,具有良好的煤层气勘探潜力,是目前国内首个成功商业化开发的煤层气盆地。基于研究区已有地质成果,对影响沁水盆地煤层气富集成藏的主控地质因素与成藏模式进行分析,认为构造运动、水动力条件、煤层埋深、煤岩组成及热演化程度是控制沁水盆地煤层气成藏的主要地质因素,高镜质组含量、高热演化程度、弱水动力条件和较大的埋深是煤层气成藏的有利条件,向斜是煤层气富集成藏的有利部位。     

地勘单位经济指标考核体系探讨

地勘单位执行多年的经济指标考核体系一般由决算总收入、新增资本积累、净资产总额、应收账款与存货占经营收入比率、提取折旧额、提交煤炭资源量,人均年收入等七项指标组成。该指标体系经过多年运行,已经趋于成熟。但是该指标考核体系没有考虑到不同单位的综合经济实力和生产能力水平的差异,忽略了不同单位之间的主营业务性质和区域性差异,使考核结果公平性存在一定的缺陷。本文依据全面考核原则、科学考核原则、可操作性原则,探讨了如何改进经济指标考核体系,并提出了可供实施的企业经济效益综合指数考核指标体系。     

High lipid content and productivity of microalgae cultivating under elevated carbon dioxide

This study examined the cell growth rate, lipid contents, lipid productivity, chlorophyll a concentration, and carbon dioxide tolerance of Chlorella vulgaris under various cultivation conditions. The pH, concentration of carbon dioxide in media, and light intensity variables were manipulated to obtain high lipid productivity. The optimum conditions were at pH 7.0, 2,930 lux, and 30 % carbon dioxide. Biomass concentration reached 1,288, 1,130, and 1,083 mg L^?1 at 15, 30, and 50 % CO₂ after 6 days, respectively, implying that this strain has appreciable tolerance to carbon dioxide. The highest concentration of chlorophyll a occurred at 2,930 lux and decreased with increasing light intensity gradually. The maximum specific growth rate was 3.25 day^?1 based on the dry weight and 4.63 day^?1 based on the cell number. The lipid content (45.68 %) and lipid productivity (86.03 mg day^?1 L^?1) obtained in this study are higher than reported values in literatures. Hence, C. vulgaris is a good candidate for subsequent research in biodiesel production under elevated carbon dioxide concentration by microalgae.     

Microbiological degradation of phenol using two co-aggregating bacterial strains

Phenol biodegradation in an aerobic batch reactor was investigated using mixed two co-aggregating strains (Flavobacterium sp. and Acetobacter sp.). Response surface methodology by the Box–Behnken model was used to evaluate the optimal cell growth and phenol degradation conditions. The optimum temperature, pH value and inoculum size were found to be 33 °C, 6.06 and 13 %, respectively. In the conditions, phenol degradation rate and biomass were predicted to be 96.97 % and 410.78 mg/L within the range examined, respectively. Less toxic acetaldehyde, ethanol and acetic ether were identified as main intermediate products from the degraded samples using GC–MS. Substrate inhibition was calculated from experimental biomass growth and phenol degradation parameters using the Haldane equation. Kinetic parameters derived from nonlinear regression with correlation factors (R ²) were 0.9682 for phenol degradation and 0.9594 for biomass growth, respectively. The phenol concentration to avoid substrate inhibition was 278.17 mg/L.     

Exploring the effects of data quality,data worth,and redundancy of CO2 gas pressure and saturation data on reservoir characterization through PEST inversion

This study examined the impacts of reservoir properties on carbon dioxide (CO₂) migration after subsurface injection and evaluated the possibility of characterizing reservoir properties using CO₂ monitoring data such as spatial–temporal distributions of gas pressure, which can be reasonably monitored in practice. The injection reservoir was assumed to be located 1,400–1,500 m below the ground surface such that CO₂ remained in the supercritical state. The reservoir was assumed to contain layers with alternating conductive and resistive properties, which is analogous to actual geological formations such as the Mount Simon Sandstone unit. The CO₂ injection simulation used a cylindrical grid setting in which the injection well was situated at the center of the domain, which extended out 8,000 m from the injection well. The CO₂ migration was simulated using the latest version of the simulator, subsurface transport over multiple phases (the water–salt–CO₂–energy module), developed by Pacific Northwest National Laboratory. A nonlinear parameter estimation and optimization modeling software package, Parameter ESTimation (PEST), is adopted for automated reservoir parameter estimation. The effects of data quality, data worth, and data redundancy were explored regarding the detectability of reservoir parameters using gas pressure monitoring data, by comparing PEST inversion results using data with different levels of noises, various numbers of monitoring wells and locations, and different data collection spacing and temporal sampling intervals. This study yielded insight into the use of CO₂ monitoring data for reservoir characterization and how to design the monitoring system to optimize data worth and reduce data redundancy. The feasibility of using CO₂ saturation data for improving reservoir characterization was also discussed.     

Field experiments and numerical simulations of whirlpool foundation pit dewatering

A whirlpool foundation pit is a small-diameter, deep circular pit. Because of its depth and small diameter, a large drawdown is required, and a limited number of wells can be installed inside the pit. During excavation, partially penetrating wells inside and outside the foundation pit have to be installed to lower the water level when the aquifer is too thick. However, partially penetrating wells near partially penetrating curtains cannot be treated by analytical methods. Therefore, it is necessary to use numerical methods to predict dewatering during excavation. Field experiments were performed on whirlpool foundation pit 1880 of Baosteel Group, Shanghai, China, to obtain pumping rates and drawdown, pumping with a single well and two wells in the confined aquifer. The results indicate that the drawdown inside the pit induced by pumping wells outside the foundation pit was small, whereas it was large for pumping wells inside the pit. The pumping wells inside and outside the pit had to be combined to lower the water level. A three-dimensional numerical model was developed to simulate the dewatering process. The hydraulic conductivities of the confined aquifers were inversed by using the pumping tests. Operation schedules were simulated with the corrected model for different combinations of wells inside and outside the pit. The results suggest that different schedules and operation conditions affect drawdown. The monitored results during dewatering indicate that the simulation and field measurements were in agreement. The results can be applied to similar situations.     

Accumulation and ecological effects of soil heavy metals in conventional and organic greenhouse vegetable production systems in Nanjing,China

The spatial variability of soil heavy metals in conventional and organic greenhouse vegetable production (CGVP and OGVP) systems can reveal the influence of different farming activities on their accumulation and plant uptake. This provides important basic data for soil utilization and pollution risk assessment. Based on horizontal and vertical spatial analysis, this paper presents the spatial variability and accumulation of soil heavy metals. The effects on plant uptake and factors influencing heavy metal accumulation are presented using the two typical greenhouse vegetable sites in Nanjing City, China as examples. Results showed that different greenhouse vegetable production systems had their own dominant heavy metal accumulation, specifically, Hg and Pb in CGVP system and Cd in OGVP system. The spatial analysis showed that horizontally, distribution of soil properties and heavy metal concentrations in the two sites showed decreases from specific regions to the periphery for organic matter (OM), Cd, Cu, Hg, Pb, and Zn in CGVP and OM, As, Cd, Cu, Hg, Pb, and Zn in OGVP. Vertically, soil properties and heavy metals mainly vary in the topsoil. The key factor for the accumulation was excess fertilizer input. Variation of soil properties and the accumulation of soil heavy metals significantly influenced heavy metal uptake by plants. However, accumulation risk varied according to different heavy metals and different plant species. Environmental management of these two kinds of production systems should pay more attention to fertilizer application, plant selection, and soil properties.     

Variable temperature and moisture conditions in Yungang Grottoes,China, and their impacts on ancient sculptures

Deterioration of grottoes induced by the negative impacts of the variable temperature and moisture conditions has been an important issue in the conservation of heritage sites in China. In this case study, the spatial distributions and varying patterns of moisture and temperature in the caves of Yungang Grottoes, China, were investigated. The relative air humidity was approximately 100 % in the deep zone of the unsaturated surrounding rocks of the grottoes where the temperature remained almost steady at around 9.4 °C. However, the indoor air temperature, relative humidity, and rock surface temperature in the caves varied significantly because of the active exchange of the air with the outside atmosphere. The condensation water appeared on cave walls in the summer when the dew point in the air was higher than the rock surface temperature. Preliminary assessments with a special collection device indicated that the thickness of the transient condensation water could reach 0.03–0.10 mm on the back wall of a cave. The occurrence of this condensation water is expected to worsen salt deterioration of the sculptures in the grottoes. As revealed by long-term observations, a wooden building in front of a cave can weaken the indoor air temperature fluctuation and reduce the condensation water, and consequently, prevent the negative effects of the microclimate for the sculptures.