In the restoration of degraded wetlands,fertilization can improve the vegetation-soil-microorganisms complex,thereby affecting the organic carbon content.However,it is currently unclear whether these effects are susta...In the restoration of degraded wetlands,fertilization can improve the vegetation-soil-microorganisms complex,thereby affecting the organic carbon content.However,it is currently unclear whether these effects are sustainable.This study employed Biolog-Eco surveys to investigate the changes in vegetation characteristics,soil physicochemical properties,and soil microbial functional diversity in degraded alpine wetlands of the source region of the Yellow River at 3 and 15 months after the application of nitrogen,phosphorus,and organic mixed fertilizer.The following results were obtained:The addition of nitrogen fertilizer and organic compost significantly affects the soil organic carbon content in degraded wetlands.Three months after fertilization,nitrogen addition increases soil organic carbon in both lightly and severely degraded wetlands,whereas after 15 months,organic compost enhanced the soil organic carbon level in severely degraded wetlands.Structural equation modeling indicates that fertilization decreases the soil pH and directly or indirectly influences the soil organic carbon levels through variations in the soil water content and the aboveground biomass of vegetation.Three months after fertilization,nitrogen fertilizer showed a direct positive effect on soil organic carbon.However,organic mixed fertilizer indirectly reduced soil organic carbon by increasing biomass and decreasing soil moisture.After 15 months,none of the fertilizers significantly affected the soil organic carbon level.In summary,it can be inferred that the addition of nitrogen fertilizer lacks sustainability in positively influencing the organic carbon content.展开更多
随着互联网时代的迅猛发展,MOOC(Massive Open Online Courses)这种全球形式的互联网大型开放课程网络学习平台,以创新的教学理念与模式掀起高职教育教学改革新浪潮。MOOC平台具有工具资源多元化、课程受众面广、课程参与自主性强等方...随着互联网时代的迅猛发展,MOOC(Massive Open Online Courses)这种全球形式的互联网大型开放课程网络学习平台,以创新的教学理念与模式掀起高职教育教学改革新浪潮。MOOC平台具有工具资源多元化、课程受众面广、课程参与自主性强等方面的优势,给学习者带来不同于传统课堂教学的学习体验。本课题针对'平面设计'课程,以数字图文信息技术专业为例,通过将MOOC平台与线下实践教学相结合的课程设计教学方式,从课程多元化角度探讨课程柔性化设计方案,打造符合学生需求、有助于职业技能提升的课程教学模式。展开更多
基金supported by the National Nature Science Foundations of China(32160269)the International Science and Technology Cooperation Project of Qinghai province of China(2022-HZ-817).
文摘In the restoration of degraded wetlands,fertilization can improve the vegetation-soil-microorganisms complex,thereby affecting the organic carbon content.However,it is currently unclear whether these effects are sustainable.This study employed Biolog-Eco surveys to investigate the changes in vegetation characteristics,soil physicochemical properties,and soil microbial functional diversity in degraded alpine wetlands of the source region of the Yellow River at 3 and 15 months after the application of nitrogen,phosphorus,and organic mixed fertilizer.The following results were obtained:The addition of nitrogen fertilizer and organic compost significantly affects the soil organic carbon content in degraded wetlands.Three months after fertilization,nitrogen addition increases soil organic carbon in both lightly and severely degraded wetlands,whereas after 15 months,organic compost enhanced the soil organic carbon level in severely degraded wetlands.Structural equation modeling indicates that fertilization decreases the soil pH and directly or indirectly influences the soil organic carbon levels through variations in the soil water content and the aboveground biomass of vegetation.Three months after fertilization,nitrogen fertilizer showed a direct positive effect on soil organic carbon.However,organic mixed fertilizer indirectly reduced soil organic carbon by increasing biomass and decreasing soil moisture.After 15 months,none of the fertilizers significantly affected the soil organic carbon level.In summary,it can be inferred that the addition of nitrogen fertilizer lacks sustainability in positively influencing the organic carbon content.
文摘针对目前铁路现场对轨道电路故障的判别仍然采用阈值法导致维护效率偏低的问题,提出将神经网络与模糊逻辑相结合,构建区间二型神经模糊系统(interval type-2 neural-fuzzy system,IT2NFS),通过诊断模型实现对轨道电路故障模式的智能识别.首先通过结构识别建立初步的网络结构,采用均匀设计方法生成模糊集的均值,对训练样本进行相似性测试,生成标准差和初始后件参数;再通过递归奇异值分解,优化后件参数以减小输出误差;最后,针对常见的8种故障,从实验平台上采集样本共计9000个,其中6300个样本用于模型训练,剩余2700个用于实验测试.实验结果表明:利用IT2NFS模型进行故障诊断时,每种故障类别的识别率均在82%以上,平均正确率为90.9%,仿真用时10.59 s.
文摘随着互联网时代的迅猛发展,MOOC(Massive Open Online Courses)这种全球形式的互联网大型开放课程网络学习平台,以创新的教学理念与模式掀起高职教育教学改革新浪潮。MOOC平台具有工具资源多元化、课程受众面广、课程参与自主性强等方面的优势,给学习者带来不同于传统课堂教学的学习体验。本课题针对'平面设计'课程,以数字图文信息技术专业为例,通过将MOOC平台与线下实践教学相结合的课程设计教学方式,从课程多元化角度探讨课程柔性化设计方案,打造符合学生需求、有助于职业技能提升的课程教学模式。
