民勤咸水灌溉及SWAP模型模拟研究

 采用0.8 g·L-1和5 g·L-1浓度咸水对民勤传统作物黄河蜜进行咸水灌溉试验。通过野外试验和实验室分析,评价了咸水灌溉对土壤性质和作物产量的影响,校正了SWAP模型并对相关因子进行了模拟分析。研究结果显示,尽管基于当地种植经验的灌水量与基于潜在蒸发蒸腾量（ET0）及根据田间持水量计算的需水量有一定差异,但灌溉水质和灌水量与田间产量具有较好的一致性;0.8 g·L-1处理的水利用效率高于5 g·L-1处理,湿润年的水利用效率高于干旱年;模拟结果显示,SWAP模型对不同试验处理和不同气候条件下的土壤性质和作物产量模拟效果较好。由此得出结论,在民勤可以利用SWAP模型模拟不同环境条件下的土壤水分状况及作物产量,为农田耕作提供理论支撑。     

中国公众对"限塑令"态度的影响因素——以兰州市为例

基于问卷调查和个人访谈,运用路径方法,分析了影响中国公众对限塑令态度的社会心理和社会人口变量.结果表明,社会人口变量中,只有教育与公众对限塑令的态度呈正相关,且社会人口变量只能解释公众对限塑令态度方差的很小一部分.相较而言,社会心理变量能更好解释中国公众对限塑令态度的差异,集体主义价值观和新生态观与限塑令态度呈显著正相...     

Characteristics of the changes in tropical cyclones influencing the South Korean region over the recent 10 years (2001–2010)

Through the investigation of tropical cyclone (TC) characteristics related to climate change, this study found that the frequency of TCs occurring over the Western North Pacific has recently decreased slightly, while their average intensity has increased. The number of overall TCs that passed within the vicinity of South Korea has also been reduced, but the number of strong typhoons in the area, those with maximum wind speeds of more than 44 m/s, has significantly increased. These changes are closely related to the following phenomena. (1) The average genesis region of TCs that influence South Korea has moved eastward. Accordingly, the TCs tend to strengthen as they move westward for long distances along the Intertropical Convergence Zone (ITCZ) trade easterlies and the southern boundary of the North Pacific Subtropical High (NPSH). (2) The NPSH and Asia Monsoon trough, which are known to affect TC tracks, have extended to the northwest and southeast. This has caused TCs that travel to higher latitudes and curve back toward the Korean Peninsula to become more frequent. (3) TCs have approached the Korean Peninsula without hitting land. In addition, the sea surface temperature became higher than it was before. These factors have caused TCs to maintain their strength or become stronger than before.     

Veterinary antibiotics contamination in water, sediment, and soil near a swine manure composting facility

Antibiotics have been commonly used to prevent animal diseases and promote livestock productivity. However, its release into the surrounding environments leads to ecological disturbance and risks to human health. This study was conducted to monitor the occurrence and seasonal variations of antibiotics in water, sediment, and soil close to a swine manure composting facility, Korea. Various types of antibiotics such as tetracyclines (TCs) including tetracycline, chlortetracycline, and oxytetracycline, and sulfonamides (SAs) including sulfamethazine, sulfamethoxazole, and sulfathiazole were measured by the high-performance liquid chromatography-tandem mass spectrometry via a solid-phase extraction. In the results it was identified that the variations of measured antibiotics’ concentrations in water, sediment, and soil are depending on the season. The observed concentration levels of TCs were higher in winter than in summer season, indicating that the low temperature is a parameter attributing to interruption of its degradation in water, sediment, and soil. The concentration levels of SAs were significantly higher than those of TCs and in general, all measured antibiotics’ concentrations were also in general higher in Korea when compared to those in other countries. The long-term monitoring of antibiotics’ residues in aquatic and terrestrial environments is necessary.     

Sequestration of arsenate from aqueous solution using 2-line ferrihydrite: equilibria,kinetics, and X-ray absorption spectroscopic analysis

Arsenic(V), as the arsenate (AsO₄ ^3?) ion and its conjugate acids, has a strong affinity on Fe, Mn, and Al (oxyhydr)oxides and clay minerals. Removal of arsenate from aqueous solution by poorly crystalline ferrihydrite (hydrous ferric oxide) via a combination of macroscopic (equilibria and kinetics of sorption) and X-ray absorption spectroscopic studies was investigated. The removal of arsenate significantly decreased with increasing pH and sorption maxima of approximately 1.994 mmol/g (0.192 mol_As/mol_Fe) were achieved at pH 2.0. The Langmuir isotherm is most appropriate for arsenate sorption over the wide range of pH, indicating that arsenate sorption preferentially takes place at relatively homogenous and monolayer sites rather than heterogeneous and multilayer surfaces. The kinetic study demonstrated that arsenate sorption onto 2-line ferrihydrite is considerably fast, and sorption equilibrium was achieved within the reaction time of 2 h. X-ray absorption near-edge structure spectroscopy indicates no change in oxidation state of arsenate following interaction with the ferrihydrite surfaces. Extended X-ray absorption fine structure spectroscopy supports the efficient removal of arsenate by the 2-line ferrihydrite through the formation of highly stable inner-sphere surface complexes, such as bidentate binuclear corner-sharing (²C) and bidentate mononuclear edge-sharing (²E) complexes.     

日地系统学中的太阳活动研究（Ⅱ）爆发型太阳活动—太阳耀斑

爆发型太阳活动是日地系统中重要的扰动源。本文介绍日地系统学中最剧烈的爆发型太阳活动－太阳耀斑的观测研究进展。综述了最近两个太阳周的地面与空间观测所得到的耀斑的物理图象和统计性质，简单讨论了空间观测设备的发展和面临的研究课题。     

Changes of biochemical properties and heavy metal bioavailability in soil treated with natural liming materials

This study evaluated the efficiency of naturally occurring lime-based waste materials (oyster shells, eggshells, and mussel shells) on immobilization of selected heavy metals (Cd and Pb) and a metalloid (As) in a contaminated agricultural soil. A 30-day incubation experiment was performed using soil mixture with natural liming materials or calcite (CaCO₃) at 0, 1, 3, 5, and 10 wt %. Soil biochemical properties including pH, electrical conductivity (EC), exchangeable cations, organic matter (OM), total nitrogen (TN), microbial populations, and enzyme activities were determined to ensure the changes in soil quality during incubation. The results showed that the application of natural liming materials led to an increase in soil pH similar to that of CaCO₃. Soil concentrations of Cd, Pb, and As extracted with 0.1 or 1 M HCl, and diethylene triamine pentacetic acid (DTPA) were decreased significantly after adding liming materials, accompanied by increased microbial population and enzyme activities of dehydrogenase, phosphatase, β-glucosidase, and arylsulfatase. Additionally, eggshells and mussel shells induced significant increases in OM and TN in the soil. Application of natural liming materials offers a cost-effective way to immobilize heavy metals and metalloids in soils.     

Geologically controlled agricultural contamination and water–rock interaction in an alluvial aquifer: results from a hydrochemical study

Environmental Earth Sciences - Hydrogeochemistry data collected from three multi-level monitoring wells in a sandy alluvial aquifer located in the Keum River watershed, South Korea, are used in...     

Time stability and variability of Electronically Scanned Thinned Array Radiometer soil moisture during Southern Great Plains hydrology experiments

Variability and time‐stability analysis for field‐scale (800 m) Electronically Scanned Thinned Array Radiometer soil moisture within a satellite scale footprint (∼ 50 km) were quantified using observations from the Southern Great Plains Hydrology Experiment 1997 and 1999 (SGP97 and SGP99). The pixels' time‐stability properties were examined with respect to soil, vegetation and topographic parameters in order to determine which physical parameters can be used to identify good candidate observation locations for validating soil moisture from satellite observations and global‐scale model output. The results show that the time‐stability concept remains valid at the satellite scale. The root mean square error values were 1·47, 1·51, 1·93 and 2·32% for the 1st, 2nd, 50th and 100th most stable fields, respectively. The most stable locations had sand and clay percentages consistent with sandy loam soils and moderate to high normalized difference vegetation index values. Neither land cover nor topography properties could be used to identify potentially stable fields in the study region. Copyright © 2010 John Wiley & Sons, Ltd.     

Time Resolved Studies of a Pulsed Hollow Cathode Capillary Discharge

Experimental studies on a fast pulsed capillary discharge are presented. The discharge operates in a 0.8 mm inner diameter capillary, at 12 kV applied voltage. On axis discharge initiation is achieved by means of the hollow cathode effect. A short, less than 10 ns, XUV pulse is produced. Preliminary time resolved spectroscopic studies indicate that a hot, fast evolving short duration capillary plasma is produced.