亚磷酸钙工业废渣制取亚磷酸

研究了以亚磷酸钙工业废渣为原料制取亚磷酸的工艺条件.实验确定最佳工艺条件为:在1 500 mL去离子水中加入亚磷酸钙工业废渣500.0 g和碳酸钠350.0 g,80℃反应8h,得亚磷酸钠溶液；向亚磷酸钠溶液中加入163.3 g硫酸得到亚磷酸粗产品；加入300 mL无水乙酸萃取亚磷酸粗产品后,在蒸馏温度100℃、蒸馏真...     

转基因烟草中赖氨酸含量的提高

采用叶盘法将高赖氨酸蛋白基因导入到烟草中.GUS组织化学染色、PCR扩增、Southernblot分析表明, 该基因已经整合到烟草基因组中.测定 10株转基因烟草叶片赖氨酸含量,大部分植株有着明显的提高,最高幅度达到了49. 89%. 图 6参 11     

Assessment of opium-based farming systems: a case study in the Nahom area,Oudomxay Province in Northern Laos

SUMMARY

An interdisciplinary team of 10 completed an exploratory one-month survey of villages in Nahom, Oudomxay Province, Laos, an area representative of upland farming systems based on opium and shifting cultivation. The study included investigation of the physical and socioeconomic environments and assessment of the farming systems. Due to the relatively low population density, there is enough land for villagers to practice shifting cultivation with a one year cultivation cycle, followed by 10–12 years of fallow. The soil degradation commonly caused by shifting cultivation was not significant in this area and the soil fertility is still relatively high. However, most of the original forests had been cut down and used for shifting cultivation and some degradation of the vegetation has occurred, showing that the ecological sustainability has been threatened by prevailing practices. Thirty-six percent of the households had food supply problems for more than three months of each year. The extremely low return for labour from upland rice cultivation, only 5.64 kg per labour-day, was the critical factor that caused the food shortage. Because of poor technique, rice yield from paddy fields was also low, thus shifting cultivators have no enthusiasm to expand their paddy fields. Income from opium provided 80.5% of household income. Opium was extremely tempting to local people due to the very high return for labour, 5700 kip (US$6) per labour-day, low investment, and good labour availability (mostly during the off-season of rice cultivation). However, opium was also a ‘two-edged sword’. It did not bring real wealth, health and happiness but instead brings poverty, poor health and disappointment.     

秦皇岛市气象灾害风险评估技术研究及风险环境区划分

根据国际流行的灾害评估模式，通过对秦皇岛市气象灾害的分布和环境状况的调查，建立风险要素和风险级别的隶属关系矩阵，用层次分析法来确定风险要素权重的排序，凭借DPS数据处理软件（DataProcessingSystem）计算权重，得到综合脆弱度指数集合，获得相关区域的气象灾害风险指数得分。     

秦皇岛探测环境变化对气象要素的影响

为分析秦皇岛地面气象探测环境变化对气象要素的影响，采用距平百分率和线性倾向估计及趋势系数等方法，对秦皇岛气象站（54449）新、旧站址搬迁前后1989—1998、1999—2008年各10年，与没有迁站的昌黎站做同期资料比较，结果表明：秦皇岛探测环境变化对气象要素有显著影响：年平均气温、年极端气温较迁站前显著下降，相对湿度增大，日照时数明显减少，雾日增多。指出气象要素变化除具有随时间变化的共同差异外，主要受探测环境变化的影响。