残膜对土壤水分入渗和蒸发的影响及不确定性分析

为探究残膜对土壤水分入渗和蒸发过程的影响规律，通过室内土柱试验，设置6 个残膜量水平（0、80、160、 320、640 和1 280 kg/hm2），研究了残膜对湿润锋运移、土壤水分分布、累积入渗量和累积蒸发量及其不确定性的影响。 结果表明：随残膜量增加，湿润锋垂直运移速率和累积入渗量逐渐减小；残膜量&gt;80 kg/hm2 时，湿润锋运移速率大幅下 降；累积蒸发量随残膜量增加而递减而蒸发系数呈递增趋势，土壤保水能力减弱；随残膜量增加，0～10 和20～45 cm 含 水率呈降低趋势，而土壤水分的变异系数呈增加趋势，残膜加剧了土壤水分垂直分布的变异性，残膜量&gt;320 kg/hm2 的处 理会出现表土层&ldquo;板结&rdquo;现象；基于Gibbs 抽样算法分析表明，Kostiakov 入渗模型和Rose 蒸发模型各参数的95%后验 置信区间上下限的差值和标准差均随残膜量增加而增大，累积入渗量和累积蒸发量的95%后验置信区间面积呈增大趋势， 土壤累积入渗量和累积蒸发量的不确定性随残膜增多而增强。该研究可探明残膜污染区的土壤水分运动规律，并为提高 Kostiakov 模型、Rose 模型的模拟效率和模拟精度提供参考。</p

Monitoring long-term ecological impacts from release of Fukushima radiation water into ocean

4月13日，日本政府宣布其将福岛第一核电站的核废水排入太平洋的决定，尽管其一再强调经过处理和稀释后的核废水的辐射水平会低于饮用水设定的标准，但此举仍遭到当地渔民和附近沿海国家包括韩国、俄罗斯、中国和朝鲜的强烈反对，联合国和包括绿色和平组织等在内的非政府组织对日本这一决定表示深切担忧。国际原子能机构（IAEA）表示会对核废水的排放进行严格监督，保证其在安全水平之内。关于“福岛核辐射”的网络检索量在4月13日激增，此举引起国际上广泛关注。在此背景下，国际期刊Geography and Sustainability邀请欧洲科学院院士、发展中国家科学院院士、我校吕永龙教授研究团队撰写文章，科学分析了日本福岛核事故的生态影响及核废水排放入海会带来的潜在的生态影响，并提出了应采取的应对措施，呼吁国际科技界联合起来对此做出回应。该文的第一与通讯作者为吕永龙教授，共同作者包括苑晶晶博士以及杜荻、孙斌和易小洁三位博士生。参与单位包括厦门大学、中国科学院生态环境研究中心、中国科学院大学和中丹科教中心。【Abstract】After 10 years of the Fukushima Nuclear Accident, Japan decided to release the nuclear wastewater into the Pacific Ocean on 13 April 2021. It is apparent that Japan has chosen the most cost-efficient way to deal with the contaminated water, however, great opposition and concerns have been raised internationally due to the ecotoxicological features of radioactive materials and their harmful impacts on the environment. Here we analyze the ecological impacts caused by the nuclear accident and the potential impacts of releasing the nuclear wastewater into the ocean. Science-based solutions are proposed through a third-party evaluation and strict environmental assessment, multi-stakeholder public participation, integrated monitoring of the neighboring coastal countries, long-term international collaborative research, and setting up international convention for ecological compensation.This study was supported by the National Natural Science Foundation of China (Grant No.71761147001 and 42030707) and the International Partnership Program of the Chinese Academy of Sciences (Grant No.121311KYSB20190029). 该研究得到了国家自然科学基金（71761147001和42030707）和中国科学院国际大科学计划项目（121311KYSB20190029）的资助

砷化镓基量子级联半导体激光器材料及生长方法

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JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies