麻疯树种仁油粕脱毒

为获得经冷榨脱油后麻疯树油粕最佳的脱毒方法,采用超声提取,运用四因素三水平正交实验,考察了脱毒温度、脱毒时间、脱毒次数以及脱油后种仁与乙醇料液比对脱毒效果的影响.结果显示,最佳的脱毒方法为料液比8:1,40℃,超声3次,每次20 min.该方法处理后麻疯树油粕中佛波酯含量为0.011 mg g-1.脱毒后的麻疯树油粕对小鼠的急性毒性实验显示,小鼠无死亡,体重增长正常,未出现中毒症状,初步表明脱毒方法有效.图2表3参9     

Frequency comparative study of coal-fired fly ash acoustic agglomeration

Comparative studies between high-frequency and lowfrequency acoustic agglomeration were carried out to investigate the frequency influence on agglomeration efficiency.     

基于空间自相关模型的农村居民点时空演变格局与特征研究

农村居民点作为农村人口重要空间聚集区,其空间布局、演变特征受历史、自然、社会、经济、传统文化等多重因素的影响。科学识别农村居民点的时空分布形态,并揭示其内在的变化规律和驱动因素,对促进农村居民点科学规划、提高农村土地资源空间布局优化均具有重要意义。利用都江堰市2005和2012年两期遥感影像提取农村居民点、城镇、道路、河流等矢量数据,借助RS、GIS空间分析技术,定量研究都江堰市农村居民点时空变化过程、格局和特征,并引入空间自回归模型深入分析不同环境因素对农村居民点空间布局的影响程度。研究结果表明:(1)都江堰市农村居民点的空间分布密度存在显著的空间正相关性,即密度值较高或较低的地区在空间上呈现显著的聚集状态,但局部的空间异质性在增强;(2)密度的高值集群主要集中分布在都江堰市东南部沙西线沿线以及南部成青快速通道一线,并且有进一步沿道路延线纵深扩张的趋势,而密度的低值集群由于受地形的影响,在空间分布上变化不大,主要位于龙门山沿线的乡镇;(3)2005~2012年,地形位指数每增加1%,农村居民点的空间密度减少0.505%,而距城镇、河流和道路的距离每增加1%,农村居民点的空间密度分别增加0.124%、0.144%、0.006%;(4)不同环境因素对农村居民点空间分布的影响程度大小为:地形影响城镇辐射影响河流影响道路影响,并且随着时间的推移,各环境因素的影响程度都在不断地增强。该研究以期为今后同类研究提供一定的方法借鉴,为农村居民点动态变化监测、农村土地节约集约利用、新农村规划等提供理论方法和技术应用支撑。     

Distributional dynamic and trend evolution of China’s agricultural carbon emissions – an analysis on panel data of 31 provinces from 2002 to 2011

Researching the dynamic distribution characteristics and trend evolution of agricultural carbon emissions is of considerable significance in formulating an effective agricultural carbon reduction policy. Based on measurement of agricultural carbon emissions of 31 provinces over the period 2002–2011, the study observed regional differences and the dynamic evolution of distribution of agricultural carbon emissions using agricultural carbon intensity as the indicator, accompanied by Gini coefficients and the kernel density estimation method. The results demonstrate first that agricultural carbon emissions for China show an obvious nonequilibrium nature in regard to spatial distribution. According to the differences in agricultural carbon emissions dynamic trends, we divided the 31 regions into four types – continuous decline, fluctuating decline, continuous increase, and fluctuating increase. Further, agricultural carbon emissions intensity showed a downward trend with significant differences in the research areas. Second, the gap in spatial distribution of national agricultural carbon emissions is gradually expanding based on the results calculated by Gini coefficient. From the perception of regional differences in agricultural carbon emissions, the eastern region showed an average level, the gap was more obvious in the central region, while western region showed a trend of fluctuating downward. Third, according to estimation by kernel density, the regional disparity in agricultural carbon emissions had a downward, but limited, trend. In regard to agricultural carbon emissions over the three areas, the regional gap not only tended to decrease but also showed a “four way” differentiation phenomenon in the eastern region. The difference in the central region difference was narrower. On the whole, the gap for the western region reduced steadily over a small range.     

黄海西部降水pH值的年度及季节统计特征

采用内核密度估计方法对黄海西部降水pH值年度/季节特征进行了分析.结果显示,降水pH值年度内核密度估计图相似,呈典型双态分布,以低pH值峰为主.季节性分布特征春、夏、冬季相近,低pH值峰为主,秋季高pH值峰为主.该海域降水pH值特征是陆源输入与海源输入相互影响的结果.根据数据非正态分布特点,采用bootstrap模拟取样获得的降水pH代表值显示,黄海西部降水总体呈弱酸雨特征,年度与季节性pH代表值都呈弱酸性,且年度降水pH值变化范围要大于季节性变化,降水酸性依次为春季>冬季>秋季>夏季,季节性特征较显著.      

基于核密度估计的城市基础要素与街尘营养元素含量特征关联

了解城市基础要素与街尘污染物在空间上的关联特征有利于城市非点源污染源区的定量解释及精准控制.为探究城市基础要素与街尘营养元素含量空间分布之间的联系,以武汉市汉阳区为案例研究区,选取总氮(TN)、总磷(TP)、交换态磷(Ex-P)、铝结合态磷(Al-P)、铁结合态磷(Fe-P)、闭蓄态磷(Oc-P)、钙结合态磷(Ca-P...