Plant virus disease is one of the major causes of biological disasters in agriculture worldwide. Given the complexity of transmission media and plant disease infection mechanisms, the prevention and control of plant v...Plant virus disease is one of the major causes of biological disasters in agriculture worldwide. Given the complexity of transmission media and plant disease infection mechanisms, the prevention and control of plant viral diseases is a great challenge, and an efficient green pesticide is urgently needed. For this reason, when developing candidate drug leads to regulate plant viruses, pesticide experts have focused on characteristics such as low pesticide resistance, eco-friendliness, and novel mechanism. Researchers have also theoretically investigated the molecular targets of viruses infecting agricultural crops. Antiviral screening models have been constructed based on these molecular targets, and the mechanisms of commercial drugs and high-activity compounds have been extensively investigated. After screening, some compounds have been applied in the field and found to have good commercial prospects; these drugs may be used to create new green antiviral pesticides to control plant viruses. This paper reviews the screening, mode of action, development and application of recently used plant-based antiviral agents.展开更多
This article analyzes the effect of the balance of dispersion and nonlinearity on the quality of a transmission system with super Gauss pulse input by altering the input power and adding a section of dispersion compe...This article analyzes the effect of the balance of dispersion and nonlinearity on the quality of a transmission system with super Gauss pulse input by altering the input power and adding a section of dispersion compensation fiber (DCF). The same mechanisms are applied to a 2-channel wave divide multiplex system(WDM) as well. DCF is proved to be a good solution in both situations.展开更多
在我国经济发展逐渐转向高质量增长阶段的背景下,研究市域单元城镇化的协调发展程度对转变城市经济增长方式和推动城市高质量发展具有重要的现实意义.基于2003—2019年中国285个城市的面板数据,利用耦合协调度模型和探索性时空数据分析...在我国经济发展逐渐转向高质量增长阶段的背景下,研究市域单元城镇化的协调发展程度对转变城市经济增长方式和推动城市高质量发展具有重要的现实意义.基于2003—2019年中国285个城市的面板数据,利用耦合协调度模型和探索性时空数据分析方法从城镇化水平和城镇化质量角度对城镇化耦合协调发展水平的时空格局特征进行识别和刻画,并借助空间面板杜宾模型分析我国城镇化耦合协调发展的驱动因素及其空间效应.研究表明:研究期间内,中国城镇化耦合协调发展水平较低但呈持续上升特征,城际差异呈持续缩小特征,空间格局呈“东高西低”和“南高北低”的地带性特征.Moran s I指数表明中国城镇化耦合协调发展呈现出空间集聚分布,且集聚程度随时间不断增强;时间路径分析表明城镇化协调发展局部空间结构和空间依赖方向上稳定性较强,其空间格局演变呈动态整合的特征;时空跃迁分析表明城镇化协调发展具有明显的路径依赖和空间锁定特征.经济发展、人口规模、人力资本、科技创新、产业结构、政府能力对本地城市城镇化协调发展均具有正向直接效应;人力资本、科技创新和产业结构对邻域城镇化协调发展具有负向溢出效应,人口规模对邻域城镇化协调发展具有正向溢出效应.在未来城市发展过程中,要综合考虑城镇化协调发展的区域差异和空间溢出效应,因地制宜地制定推动城镇化高质量发展的指导意见和政策方针.展开更多
本研究采用福林酚法测定樱桃酒中总酚的含量,并通过响应面法优化其工艺参数。在单因素实验基础上,以福林酚试剂用量、碳酸钠浓度、显色温度、显色时间和碳酸钠用量为影响因素,樱桃酒总酚含量为指标,响应面法进行分析和优化。结果表明,...本研究采用福林酚法测定樱桃酒中总酚的含量,并通过响应面法优化其工艺参数。在单因素实验基础上,以福林酚试剂用量、碳酸钠浓度、显色温度、显色时间和碳酸钠用量为影响因素,樱桃酒总酚含量为指标,响应面法进行分析和优化。结果表明,优化后得到最佳条件为:福林酚试剂2.1 m L、碳酸钠浓度63 g/L、碳酸钠用量8.32 m L,在25℃件下反应1.4 h,总酚含量为1085.2±0.16 mg/L。此回归模型拟合性良好,可用于预测总酚含量。根据此线性回归方程测定12个品种樱桃酒中总酚含量最高的为俄罗斯酸樱桃(1495.0 mg/L),雷尼含量最低(442.8 mg/L)。福林酚法操作简单,可用于不同品种樱桃酒总酚含量的测定。展开更多
基金supported by the National Natural Science Foundation of China (21132003, 31460460, 21502032 and 21732002)the Subsidy Project for Outstanding Key Laboratory of Guizhou Province in China (20154004)+1 种基金the Provincial University Cooperation Plan of Guizhou Province in China (20147001)the Collaborative Innovation Center for Natural Products and Biological Drugs of Yunnan, China
文摘Plant virus disease is one of the major causes of biological disasters in agriculture worldwide. Given the complexity of transmission media and plant disease infection mechanisms, the prevention and control of plant viral diseases is a great challenge, and an efficient green pesticide is urgently needed. For this reason, when developing candidate drug leads to regulate plant viruses, pesticide experts have focused on characteristics such as low pesticide resistance, eco-friendliness, and novel mechanism. Researchers have also theoretically investigated the molecular targets of viruses infecting agricultural crops. Antiviral screening models have been constructed based on these molecular targets, and the mechanisms of commercial drugs and high-activity compounds have been extensively investigated. After screening, some compounds have been applied in the field and found to have good commercial prospects; these drugs may be used to create new green antiviral pesticides to control plant viruses. This paper reviews the screening, mode of action, development and application of recently used plant-based antiviral agents.
文摘This article analyzes the effect of the balance of dispersion and nonlinearity on the quality of a transmission system with super Gauss pulse input by altering the input power and adding a section of dispersion compensation fiber (DCF). The same mechanisms are applied to a 2-channel wave divide multiplex system(WDM) as well. DCF is proved to be a good solution in both situations.
文摘在我国经济发展逐渐转向高质量增长阶段的背景下,研究市域单元城镇化的协调发展程度对转变城市经济增长方式和推动城市高质量发展具有重要的现实意义.基于2003—2019年中国285个城市的面板数据,利用耦合协调度模型和探索性时空数据分析方法从城镇化水平和城镇化质量角度对城镇化耦合协调发展水平的时空格局特征进行识别和刻画,并借助空间面板杜宾模型分析我国城镇化耦合协调发展的驱动因素及其空间效应.研究表明:研究期间内,中国城镇化耦合协调发展水平较低但呈持续上升特征,城际差异呈持续缩小特征,空间格局呈“东高西低”和“南高北低”的地带性特征.Moran s I指数表明中国城镇化耦合协调发展呈现出空间集聚分布,且集聚程度随时间不断增强;时间路径分析表明城镇化协调发展局部空间结构和空间依赖方向上稳定性较强,其空间格局演变呈动态整合的特征;时空跃迁分析表明城镇化协调发展具有明显的路径依赖和空间锁定特征.经济发展、人口规模、人力资本、科技创新、产业结构、政府能力对本地城市城镇化协调发展均具有正向直接效应;人力资本、科技创新和产业结构对邻域城镇化协调发展具有负向溢出效应,人口规模对邻域城镇化协调发展具有正向溢出效应.在未来城市发展过程中,要综合考虑城镇化协调发展的区域差异和空间溢出效应,因地制宜地制定推动城镇化高质量发展的指导意见和政策方针.
文摘本研究采用福林酚法测定樱桃酒中总酚的含量,并通过响应面法优化其工艺参数。在单因素实验基础上,以福林酚试剂用量、碳酸钠浓度、显色温度、显色时间和碳酸钠用量为影响因素,樱桃酒总酚含量为指标,响应面法进行分析和优化。结果表明,优化后得到最佳条件为:福林酚试剂2.1 m L、碳酸钠浓度63 g/L、碳酸钠用量8.32 m L,在25℃件下反应1.4 h,总酚含量为1085.2±0.16 mg/L。此回归模型拟合性良好,可用于预测总酚含量。根据此线性回归方程测定12个品种樱桃酒中总酚含量最高的为俄罗斯酸樱桃(1495.0 mg/L),雷尼含量最低(442.8 mg/L)。福林酚法操作简单,可用于不同品种樱桃酒总酚含量的测定。
