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Exploring the rules of cropland elevation uplift in China 被引量:1
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作者 YUAN Jin-tao CHEN Wan-xu +1 位作者 ZENG Jie ye xin-yue 《Journal of Mountain Science》 SCIE CSCD 2023年第7期1824-1841,共18页
Cropland elevation uplift(CLEU) has recently become a new challenge for agricultural modernization,food security,and sustainable cropland use in China.Uncovering the rules of CLEU is of great theoretical and practical... Cropland elevation uplift(CLEU) has recently become a new challenge for agricultural modernization,food security,and sustainable cropland use in China.Uncovering the rules of CLEU is of great theoretical and practical significance for China’s sustainable agricultural development and rural revitalization strategy.However,existing studies lack in-depth disclosure of multi-scale CLEU evolution rules,making it difficult to support the formulation of specific cropland protection policies.We analyzed the spatio-temporal evolution and multiscale CLEU in China from 1980 to 2020 using the Lorenz curve,gravity center model,hotspot analysis,and cropland elevation spectrum.The results indicated that the center of gravity of cropland moved to the northeast from 1980 to 2000 and then shifted to the northwest.The spatial distribution of cropland became increasingly imbalanced from 1980 to 2000.The change hotspots clustered in the northwest and the northeast,whereas cold-spots were mainly in southeastern China.The average elevation of cropland increased by 17.38 m,and the elevation uplift rule in different regions differed evidently across scales.From 1980 to 2000,all provinces except Xinjiang,Inner Mongolia,Gansu,and Yunnan exhibited CLEU,with Qinghai,Tibet,Beijing,and Guangdong showing the most noticeable uplifting.The CLEU can alleviate the shortage of cropland to some extent.However,without a planning constraint,the CLEU will lead to the increase of ecological risk and food security risk. 展开更多
关键词 CROPLAND Elevation uplift rules MULTI-SCALE Elevation spectrum China
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贵州海鲜菇栽培原料来源分析及优质营养物筛选 被引量:1
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作者 叶欣悦 贺卓 须文 《中国食用菌》 2022年第7期35-40,48,共7页
“十三五”以来,贵州省食用菌产业快速发展,已成为带动农民脱贫致富的优势产业之一。以贵州省剑河县、三都县、兴义市和毕节市的海鲜菇栽培企业和基地为重点,对贵州省海鲜菇栽培的培养料种类、来源进行调研,对海鲜菇工厂化栽培营养物中... “十三五”以来,贵州省食用菌产业快速发展,已成为带动农民脱贫致富的优势产业之一。以贵州省剑河县、三都县、兴义市和毕节市的海鲜菇栽培企业和基地为重点,对贵州省海鲜菇栽培的培养料种类、来源进行调研,对海鲜菇工厂化栽培营养物中的粗蛋白、纤维素、半纤维素、总碳含量、碳氮比、重金属等指标进行分析和测定,确定了栽培原料的优质主料和辅料物质来源。结果表明,新疆出产的1号棉籽壳、贵州出产的木屑、山东出产的玉米芯、河南出产的2号玉米粉和山东出产的麸皮可作为贵州海鲜菇工厂化栽培原材料供应的首选来源。并对贵州省海鲜菇生产原料存在的问题进行分析,对培养料的开发提出了相关建议。 展开更多
关键词 海鲜菇 贵州省 栽培原料 工厂化栽培
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Climate change and Chinese farmers: Perceptions and determinants of adaptive strategies 被引量:10
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作者 ZHAI Shi-yan SONG Gen-xin +2 位作者 QIN Yao-chen ye xin-yue Mark Leipnik 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2018年第4期949-963,共15页
Farmers’ perceptions, beliefs, adaptive strategies, and barriers regarding climate change are critical to promoting sustainable ecosystems and societal stability. This paper is based on an extensive survey of 1 500 f... Farmers’ perceptions, beliefs, adaptive strategies, and barriers regarding climate change are critical to promoting sustainable ecosystems and societal stability. This paper is based on an extensive survey of 1 500 farmers and their households in Henan Province in China during 2013–2014. Henan is the largest agricultural province in China with over 51 million farmers. The survey results showed that approximately 57% of the respondents perceived the direct impact of climate change during the past 10 years, with 70.3% believing that climate change posed a risk to their livelihood. Not surprisingly, most farmers reported that they have adopted new measures to mitigate the negative impacts of climate change. The main barriers hindering farmers’ adopting adaptation measures were lack of funds and timely information. A multinomial logit model revealed that land ownership, knowledge of crop variety and the causes of climate change, as well as the belief of climate change, were all positively related to the likelihood of employing adaptive strategies. Moreover, the percentage of households engaging in agriculture activity, and years of engaging in farming were both negatively correlated with famer’s likelihood of adopting adaptation strategies. More importantly, farmers with high incomes were less likely to adopt adaptive strategies and more willing to engage in other business activities. In conclusion, it is important to communicate climate change related information and government policies in rural areas, promote farmer associations and other educational outreach efforts to assist Chinese farmers to deal with climate change. 展开更多
关键词 climate change Chinese farmers adaptive strategies Henan Province
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城市群视角下的产业共聚与产业空间治理:机器学习算法的测度 被引量:22
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作者 陈露 刘修岩 +1 位作者 叶信岳 胡汉辉 《中国工业经济》 CSSCI 北大核心 2020年第5期99-117,共19页
城市群是未来中国产业发展的主要空间载体与重要地理单元。本文在机器学习Wasserstein距离算法思想的基础上,运用矩阵扩张Sinkhorn算法和熵正则化约束法改进Wasserstein距离算法及其求解方式,通过假设检验与蒙特卡洛模拟构建产业共聚指... 城市群是未来中国产业发展的主要空间载体与重要地理单元。本文在机器学习Wasserstein距离算法思想的基础上,运用矩阵扩张Sinkhorn算法和熵正则化约束法改进Wasserstein距离算法及其求解方式,通过假设检验与蒙特卡洛模拟构建产业共聚指数,测算中国城市群的产业共聚水平。测度结果发现,中国城市群同二位数行业内产业间的共聚水平大于跨二位数行业产业间共聚水平;经济相对落后的城市群表现出明显的产业共聚特征,同时技术密集型产业在上述城市群内部偏向共聚;2007—2013年间中国城市群产业空间共聚水平总体呈下降态势,不同城市群的演化模式存在差异。本文还利用产业共聚指数的方向性,分析了不同城市群产业空间核心产业的差异,绘制出城市群产业空间结构。对产业共聚影响因素的实证研究发现,投入产出关联、技术关联与规模差距对产业间共聚的影响显著为正,行业内部竞争水平从共聚和被共聚两个方向抑制产业间共聚趋势;城市群层面诸如政府规模等区域特征均与产业间共聚水平负相关。据此,本文提出了实施城市群产业空间治理的相应政策建议。 展开更多
关键词 产业共聚 产业空间治理 机器学习算法 城市群
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高精度混凝土空心砌块的砌筑及免抹灰技术研究 被引量:1
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作者 张超 张景煜 +1 位作者 叶新月 吴良音 《建筑机械化》 2022年第9期54-56,共3页
结合某项目施工实例,研究探讨了高精度混凝土空心砌块砌筑及免抹灰技术,此项技术采用高精度砌块设置咬槎企口,砌筑时使用SH薄层砌筑粘结砂浆,在墙面采用SH柔性抗裂内墙腻子打底,减少了墙体开裂、抹灰空鼓等质量问题的产生.运用该项技术... 结合某项目施工实例,研究探讨了高精度混凝土空心砌块砌筑及免抹灰技术,此项技术采用高精度砌块设置咬槎企口,砌筑时使用SH薄层砌筑粘结砂浆,在墙面采用SH柔性抗裂内墙腻子打底,减少了墙体开裂、抹灰空鼓等质量问题的产生.运用该项技术可以取得较好的经济、环境和社会效益,该项技术值得推广并广泛应用. 展开更多
关键词 混凝土空心砌块 免支模 免抹灰 高精度 柔性抗裂内墙腻子
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