环境铜污染影响及修复的研究现状综述

综述了铜污染对不同生物（包括植物、动物、土壤微生物）影响的研究现状,指出了Cu污染对高等植物毒害作用的研究目前主要集中在对植物生长指标、光合作用、细胞结构、细胞分裂、酶系统和其他营养元素的吸收上;高Cu对高等动物毒害作用的研究非常多,目前主要集中在对动物生产性能、体内重要的铜酶、代谢酶及重要组织器官结构功能的影响;Cu污染对土壤微生物影响的研究主要集中在微生物量及微生物群落结构的变化。探讨了尽量减少铜污染和进行修复的措施。     

土地利用总体规划环境影响评价研究——以重庆市忠县为例

土地利用总体规划环境影响评价是针对土地利用的宏观结构调整与布局对环境可能造成的影响做出的预测性评估.笔者以重庆市忠县为例,分别从土地利用结构变化、土地利用布局调整和重点建设     

超声波辅助萃取毛葱油工艺的响应面法优化

采用有机溶剂为载体对毛葱油进行超声波辅助萃取。在单因素和响应面优化设计试验的基础上,确定了最佳提取工艺条件:以二氯甲烷为萃取剂,料液比1:3,超声功率209W,超声时间37 min,超声温度31℃,在此条件下,毛葱油得率可达4.45g/kg。得到的毛葱油为棕色黏稠液体。     

紫色甘薯花青素的提取工艺研究

对超声波辅助提取紫色甘薯花青素的工艺条件进行了研究,以花青素的提取率为评价指标,在单因素试验的基础上,利用响应面法对提取工艺条件进行优化。在分析了各因素的显著性和交互作用后,得出超声波辅助提取紫色甘薯花青素的最佳提取工艺:提取时间40 min,提取温度75℃,液料比10∶1,在此条件下,所得花青素提取率为1.70%。     

Ratio control strategy for solving system response lag of continuously variable transmission system

Generally, there’s a system response lag in the continuously variable transmission system, and this leads to a deviation of the engine work point from the optimal operation line of the minimum fuel consumption. To reduce the influence of system response lag, a new CVT ratio control strategy with the system response lag parameter during computing target ratio is proposed. Simulation results indicate that the proposed control strategy can overcome the effect of system response lag, so as to keep the engine work point on the optimal operation line effectively. A comparison of fuel consumption is made between the proposed control strategy and the traditional one by simulation, and results indicate that the proposed control strategy reduces the fuel consumption of the system by 2.85％.     

Transpirational response to water availability for winter wheat as affected by soil textures

Soil texture and evaporative demand have been reported to be the main factors which influence the transpirational response to soil water deficits. However, experimental evidences are not enough. The objective of this study was to investigate the transpirational response to soil water availability in soils of different textures under different evaporative demand levels. The three main soils of the Loess Plateau of China (loamy clay, clay loam and sandy loam) were selected and six constant soil water treatments were applied for winter wheat (Triticum aestivum L.) grown in pots. In order to reduce the influence of environmental conditions and plant factors, a normalized daily transpiration rate was used to develop the relationships with volumetric soil water content and soil water suction. Results showed that, under various levels of evaporative demand, a linear-plateau function with a critical value could be used to describe the dynamic change of the normalized transpiration rate with soil drying. Soil texture significantly influenced both the critical and the slope values of the linear-plateau equations, however, evaporative demand significantly affected the critical values of volumetric soil water content and soil suction for the loamy clay and clay loam only. Therefore, for saving water, different strategies are needed for these three soils.     

Comparison of drip and sprinkler irrigation strategies on sunflower seed and oil yield and quality under Mediterranean climatic conditions

This study compares the effects of different irrigation regimes on seed yield and oil yield quality and water productivity of sprinkler and drip irrigated sunflower (Helianthus annus L.) on silty-clay-loam soils in 2006 and 2007 in the Mediterranean region of Turkey. In sprinkler irrigation a line-source system was used in order to create gradually varying irrigation levels. Irrigation regimes consisted of full irrigation (I₁) and three deficit irrigation treatments (I₂, I₃ and I₄), and rain-fed treatment (I₅). In the drip system, irrigation regimes included full irrigation (FI-100), three deficit irrigation treatments (DI-25, DI-50, DI-75), partial root zone drying (PRD-50) and rain-fed treatment (RF). Irrigations were scheduled at weekly intervals both in sprinkler and drip irrigation, based on soil water depletion within a 0.90 m root zone in FI-100 and I₁ plots. Irrigation treatments influenced significantly (P < 0.01) sunflower seed and oil yields, and oil quality both with sprinkler and drip systems. Seed yields decreased with increasing water stress levels under drip and sprinkler irrigation in both experimental years. Seed yield response to irrigation varied considerably due to differences in soil water contents and spring rainfall distribution in the experimental years. Although PRD-50 received about 36% less irrigation water as compared to FI-100, sunflower yield was reduced by an average of 15%. PRD-50 produced greater seed and oil yields than DI-50 in the drip irrigation system. Yield reduction was mainly due to less number of seeds per head and lower seed mass. Soil water deficits significantly reduced crop evapotranspiration (ET), which mainly depends on irrigation amounts. Significant linear relationships (R² = 0.96) between ET and oil yield (Y) were obtained in each season. The seed yield response factors (ky_seed) were 1.24 and 0.86 for the sprinkler and 1.19 and 1.06 for the drip system in 2006 and 2007, respectively. The oil yield response factor (ky_oil) for sunflower was found to be 1.08 and 1.49 for both growing seasons for the sprinkler and 1.36 and 1.25 for the drip systems, respectively. Oil content decreased with decreasing irrigation amount. Consistently greater values of oil content were obtained from the full irrigation treatment plots. The saturated (palmitic and stearic acid) and unsaturated (oleic and linoleic acid) fatty acid contents were significantly affected by water stress. Water stress caused an increase in oleic acid with a decrease in linoleic acid contents. The palmitic and stearic acid concentrations decreased under drought conditions. Water productivity (WP) values were significantly affected by irrigation amounts and ranged from 0.40 to 0.71 kg m⁻³ in 2006, and from 0.69 to 0.91 kg m⁻³ in 2007. The PRD-50 treatment resulted in the greatest WP (1.0 kg m⁻³) and irrigation water productivity (IWP) (1.4 kg m⁻³) in both growing seasons. The results revealed that under water scarcity situation, PRD-50 in drip and I₂ in sprinkler system provide acceptable irrigation strategies to increase sunflower yield and quality.     

基于PLC的无糖组培微环境控制系统

为实现组培微环境CO2 增施的长期自动控制 ,解决增施CO2 过程中可能将空气中杂菌引入组培箱的问题 ,设计开发了一套基于PLC的无糖组培微环境控制系统。系统以PLC为控制核心 ,采用定量供给的CO2 增施控制策略 ,可根据设定要求将固定量的高压、高纯度CO2 气体直接供入组培箱 ,并可对组培箱内湿度进行调控。系统调试试验结果表明 ,控制系统能将光期组培箱内CO2 摩尔分数和相对湿度分别控制在 70 0～ 90 0 μmol·mol-1和80 %～ 92 %的目标范围内 ,达到了预期效果     

土壤Zn向白菜茎叶的转移能力

研究了采自福建不同地区的 26个土壤的Zn向白菜茎叶的转移能力.结果表明,虽然用DTPA提取的有效Zn与茎叶Zn含量之间无显著相关,但以DTPA有效Zn为基础的Zn转移系数与土壤有效Zn之间呈极显著的幂函数相关,这种幂函数相关将白菜茎叶Zn含量与土壤有效Zn联系起来.在土壤Zn与作物Zn含量无显著相关的情况下,可用Zn转移系数(DTPA基)与土壤有效Zn之间的幂函数关系估计土壤Zn的环境质量限量.     

几种利用方式下酸性硫酸盐土的环境风险及其连锁效应

研究并比较了不同利用方式下酸性硫酸盐土酸形态和铝形态的结构特征,分析了硫形态与酸形态、酸形态与铝形态之间的相关性。研究发现,酸性硫酸盐土的不同利用类型中,土壤酸度由大到小依次为:鱼塘塘基、荒稻田>稻田>荒旱地>改良稻田>蔗田>红树林迹地;活性铝含量由高到低依次为:荒旱地>鱼塘塘基、荒稻田>稻田>改良稻田>蔗田>红树林迹地。土壤酸度和铝形态含量的层间差异较为显著,多数随深度增加呈逐渐上升的趋势。酸性硫酸盐土中的硫形态—酸—铝形态之间有明显的连锁关系。