Mechanism of cadmium resistance and adsorption of a yeast strain Rhodotorula sp. Y11

The mechanism of cadmium resistance of a yeast strain Rhodotorula sp. Y11 isolated from mine soil was investigated. We found that the yeast cells treated with different methods showed different cadmium-adsorption models. Grown in medium supplied with 100 mg/L of cadmium, 3.29% of the cell-absorbed cadmium was accounted in the cytoplasm. However, only 1% was taken into the cytoplasm and 99% was bound to the cell wall using the lyophilized biomass to adsorb cadmium in double distilled water. Treatments with alkali, ethanol-chloroform and proteinase showed different influences on the biosorption of whole cells and isolated cell walls. FT-IR analysis showed that acetyl of chitin was the active compound in the cells to absorb cadmium. The production of Metallothioneins, proteins related to the resistance to heavy metal in yeast, was evidently induced by cadmium, achieving 638.8 μg/g wet weight, which was about 85 folds higher than that in the uninduced biomass and was also much higher than that reported previously. The molecular weight of Metallothioneins was 6500 Da estimated by SDS-PAGE.     

Deflation rates of different clastic sediments in the arid regions of China

By wind tunnel experiment, we studied the deflation rates of 8 different clastic sediments in the arid regions of China, discussed the sources of aeolian sand and their influence on the development of sand dunes and formation of sand deserts from the view of dynamics of wind erosion. The average deflation rates of 8 typical clastic sediments in the arid regions of China can be arranged in the order of lacustrine sand > alluvial sand > weathered sandstone and shale > pluvial sediments > fluvioglacial sand > weathered granite > slope deposit > glacial sediments. The deflation rates exhibited strong positive correlations with the erodible particle (0.063–2mm) content and sorting features. In contrast, the deflation rates had obvious negative correlations with the contents of silt clay (<0.063 mm) and gravel (>2 mm). According to the deflation rates, the 8 typical clastic sediments can be divided into four categories: (1) lacustrine and alluvial sand, which are readily prone to wind erosion, assumed to be the main source of aeolian sand; (2) weathered sandstone and shale, pluvial sediments and fluvioglacial sand with considerable deflation rates, might be the secondary source of aeolian sand; (3) weathered granite and slope deposit having the lower deflation rates, could supply a little aeolian sand; and (4) glacial sediments with a strong anti-erodibility, could hardly offer any aeolian sand. In addition to the strong wind conditions, the exposure of extensive lacustrine sand induced by the desiccation of inland lake basin, as well as the pre-sorting of clastic sediments by flowing water should be the key factors influencing the development of sand deserts in China. The possible reason the sand deserts in China being mostly distributed around the inland lake basins and along riverbanks could be better understood through sand source analysis.     

贯通式潜孔锤新技术在矿山勘探中的应用试验

针对栾川钼矿复杂地层勘探遇到的技术难题,采用贯通式潜孔锤全孔反循环钻进工艺方法,对钻进中遇到的开孔难、漏失严重、活塞断裂等技术问题,进行了工艺研究、设计方案改进。试验表明,该技术方法具有岩芯(样)采取率高、钻进速度快的特点。     

2000年第10号台风的水汽分析与试验

本文先用NCEP再分析资料分析了2000年第10号“碧利斯”台风过程福建暴雨的水汽来源,指出本次福建暴雨过程水汽输送来自台风环境场和中低层东亚夏季风。然后用中尺度模式(MM5)模拟分析了中低层水汽变化对台风登陆前后台风暴雨过程的影响,结果表明水汽变化对降水强度、台风自身强度有非常大的影响。单层水汽敏感性试验结果表明,850 hPa层次上水汽对降水的作用最强。     

Experimental research on adsorption/desorption for petroleum pollutants in the soil in Daqing oilfield

The Daqing oilfield is one of the biggest oilfields in the world. It has been exploited for several decades, which brings serious pollution to local natural environment. The crude oil on ground which is produced in the process of oil production contains various organic pollutants. The petroleum pollutants tend to adsorb, desorb, biodegrade and photolyze and so on in the soil, but adsorption/desorption is a pair of extremely important environment geochemistry behavior. In order to master the rule of petroleum pollutants migration and transformation in the soil environment, and provide scientific evidence for the prevent research project on petroleum pollution treatment in the Daqing oilfield, the chemozem was selected as the experimental sample, which is a kind of representative soil in the Daqing oilfield. The factors affecting adsorbent and desorption＇s characteristics were discussed, including pH of the soil, the concentrations of suspended particulates and temperature. The oscillation-equity was used in the experiment. The mechanism and dynamics process of the adsorption/desorption were researched. The results showed that adsorbing of the petroleum pollutants on the chemozem sediment is a kind of physical adsorption phenomenon. The adsorption function comes from the hydrophobic and sticky character of the petroleum its self. The velocity of adsorption and desorption is almost equivalent, both concentrations of water in the soil are close to the balance in two hours, thus they achieve homeostasis in three hours. The process of adsorption of the petroleum pollutants responses to Herry isothermal model, with increasing pH, concentration of suspended particulates and temperature, the quantity of adsorption show a descending trend. However, desorption is a contrary course of adsorption in the experiment. Due to various influenced phenomena reflect that the soil in the Daqing oilfield has factors, the quantity of desorption shows an ascending trend. These strong adsorption ability to petroleum pollutants.     

Seasonal variations of adsorption/desorption equilibrium concentrations of P at water-sediment interface in the Meiliang Bay, Taihu Lake, China

Seasonal variations of adsorption/desorption equilibrium were investigated by collecting overlying water and seasonal sediment from the Meiliang Bay, Taihu Lake, China. At the same time, seasonal variations of TP and P fractions＇ concentrations in the initial and end of adsorption experiment were also carried out. In addition, the effects of temperature on the P translocation process were also conducted and discussed. The following conclusions were obtained： The sequence of adsorption/desorption equilibrium concentrations of P at water-sediment interface was spring〈winter〈autumn. In sediment the concentrations of TP decline. Concentration P decreased with temperature.     

Speciation and role of iron in cloud droplets at the puy de Dôme station

Iron is the most abundant transition metal in the atmosphere and can play a significant role in cloudwater chemistry where its reactivity is closely related to the partitioning between Fe(II) and Fe(III). The objective of this work is to determine the total iron content and the iron speciation in a free tropospheric site, and to understand which factors influence these parameters. We collected 147 samples of cloudwater during 34 cloud events over a period of four years at the puy de Dôme summit. Besides iron we measured other chemical compounds, solar radiation, physico-chemical and meteorological parameters potentially connected with iron reactivity. The total iron concentrations ranged from 0.1 to 9.1 μM with the major frequency occurring at low levels. The pH and presence of organic complexants seem to be the most significant factors connected with total dissolved iron; while the iron oxidation state seems to be an independent factor. Light intensity, presence of complexants or oxidants (H₂O₂) do not influence the Fe(II)/Fe(Total) ratio, that was quite constant at about 0.75. This could be due to the potential redox that forces the Fe(II)-Fe(III) couple to the reduced form or, more probably to the complexation by Natural Organic Matter, that can stabilize iron in its reduced form and prevent further oxidation. Our field measurements did not show the diurnal cycle observed in surface water and predicted by models of atmospheric chemistry. This result prompts a more careful review of the role of iron and, by analogy, all the transition metals in atmospheric liquid phase, often over-estimated in the literature.     

2维DLT变换用于建筑物变形监测的试验研究

直接线性变换(D irect LinearTransformation)解法是建立观测点像方空间坐标和同名点物方空间坐标之间直接线性关系的算法。本次试验通过使用普通数码相机,并应用2维直接线性变换进行了建筑物变形监测的试验研究,试验结果表明,使用普通数码相机代替常规测量方法能够满足变形监测三等精度要求。     

Detection of model voids by identifying reverberation phenomena in GPR records

In order to improve the reliability of the ground penetrating radar (GPR) method in identifying subsurface sinkholes and karst cavities, laboratory investigations have been performed. The main objective of this work was to examine the relationship between horizontal/vertical voids dimensions and wavelengths of various antennas, and the corresponding GPR responses. Emphasis was given to the investigation of the factors that cause the appearance of reverberation phenomena in the signal pattern.The tests were conducted in 5 m × 10 m area by 2-m-deep trench filled with homogenous, dry sand. The voids models (empty fiberglass cylinders in diameters of 0.6 m, 1.0 m, 1.5 m and 2.4 m, with various heights) were buried vertically with their tops at depths of between 0.7 and 1.5 m. Investigations were performed for the various model conditions by towing 500, 300 and 100 MHz antennas along a pre-established grid, for the various model conditions.The GPR data collected using the 500 MHz bistatic antenna above the 1.0-m- and the 1.5-m-diameter cylinders, and using the 300 MHz bistatic antenna above the 1.5-m-diameter cylinder, confirmed the presence of a reverberation phenomenon, i.e. a strong convex signal pattern, containing a series of high amplitude extending oscillations with reduced frequency.Based on past practical GPR experience of void detection and presently obtained experimental data, two rules of thumbs may be adopted for the prediction of the appearance of resonant radar pictures:

1. The void diameter larger than the wavelength in air of the antenna used.

2. The vertical size of the empty void not significantly smaller than its horizontal dimension.

The strong reverberations generated by the inner surface of the void targets were found to approximate standing waves generated in cylindrical waveguides and waveguide resonators. The theoretical, experimental and practical results obtained concur.