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Trade-offs between ecosystem service provision and the predisposition to disturbances: a NFI-based scenario analysis 被引量:2
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作者 Christian Temperli Clemens Blattert +2 位作者 Golo Stadelmann Urs-Beat Brändli Esther Thürig 《Forest Ecosystems》 SCIE CSCD 2020年第3期349-365,共17页
Background: Scenario analyses that evaluate management effects on the long-term provision and sustainability of forest ecosystem services and biodiversity(ESB) also need to account for disturbances. The objectives of ... Background: Scenario analyses that evaluate management effects on the long-term provision and sustainability of forest ecosystem services and biodiversity(ESB) also need to account for disturbances. The objectives of this study were to reveal potential trade-offs and synergies between ESB provision and disturbance predisposition at the scale of a whole country.Methods: The empirical scenario model MASSIMO was used to simulate forest development and management from years 2016 to 2106 on 5086 sample plots of the Swiss National Forest Inventory(NFI). We included a businessas-usual(BAU) scenario and four scenarios of increased timber harvesting. Model output was evaluated with indicators for 1) ESB provision including a) timber production, b) old-growth forest characteristics as biodiversity proxies and c) protection against rockfall and avalanches and 2) for a) storm and b) bark beetle predisposition.Results: The predisposition indicators corresponded well(AUC: 0.71–0.86) to storm and insect(mostly bark beetle)damage observations in logistic regression models. Increased timber production was generally accompanied with decreased predisposition(storm: >-11%, beetle: >-37%, depending on region and scenario), except for a scenario that promoted conifers where beetle predisposition increased(e.g. + 61% in the Southern Alps). Decreased disturbance predisposition and decreases in old-growth forest indicators in scenarios of increased timber production revealed a trade-off situation. In contrast, growing stock increased under BAU management along with a reduction in conifer proportions, resulting in a reduction of beetle predisposition that in turn was accompanied by increasing old-growth forest indicators. Disturbance predisposition was elevated in NFI plots with high avalanche and rockfall protection value.Conclusions: By evaluating ESB and disturbance predisposition based on single-tree data at a national scale we bridged a gap between detailed, stand-scale assessments and broader inventory-based approaches at the national scale. We discuss the limitations of the indicator framework and advocate for future amendments that include climate-sensitive forest development and disturbance modelling to strengthen decision making in national forest policy making. 展开更多
关键词 DISTURBANCE Ecosystem services Empirical model Forest inventory Scenario analysis
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浮选泡沫图像特征提取方法研究进展 被引量:1
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作者 宛鹤 陆笑科 +4 位作者 屈娟萍 薛季玮 张崇辉 王森 卜显忠 《中国钼业》 2024年第1期1-8,共8页
机器视觉作为设备操作人员的工具,在泡沫浮选设备的监测中得到了广泛的应用。利用泡沫图像数据集建立预测识别模型,以初级泡沫特征参数为输入,以品位和回收率等浮选指标为输出。根据是否需要手动提取浮选泡沫图像特征,可以将特征提取算... 机器视觉作为设备操作人员的工具,在泡沫浮选设备的监测中得到了广泛的应用。利用泡沫图像数据集建立预测识别模型,以初级泡沫特征参数为输入,以品位和回收率等浮选指标为输出。根据是否需要手动提取浮选泡沫图像特征,可以将特征提取算法划分为两大类别:一种是基于颜色、形态特征等的传统手动特征提取方法,另一种是基于深度神经网络的自动特征提取方法。本文总结并归纳了近年来浮选泡沫图像特征提取算法领域的研究进展,分析了各种方法的优势和不足,对当前难以人工识别泡沫状态及实现浮选自动化提升浮选效率,具有一定的指导价值。 展开更多
关键词 泡沫浮选 泡沫图像 机器视觉 泡沫图像特征
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基于改进MobileNet V3的矿物智能识别模型
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作者 宛鹤 张金艳 +4 位作者 屈娟萍 张崇辉 薛季玮 王森 卜显忠 《金属矿山》 CAS 北大核心 2024年第1期174-181,共8页
针对当前矿物识别领域存在的精度不佳、适应性差、携带不便等问题,提出了一种基于改进MobileNet V3的矿物智能识别模型(CA-MobileNet V3)。为获得研究所需的有效数据集,通过由mindat. org网站和自行拍摄方式获取的矿物图像创建了一个包... 针对当前矿物识别领域存在的精度不佳、适应性差、携带不便等问题,提出了一种基于改进MobileNet V3的矿物智能识别模型(CA-MobileNet V3)。为获得研究所需的有效数据集,通过由mindat. org网站和自行拍摄方式获取的矿物图像创建了一个包含19种矿物的数据集,对其进行数据增强处理,并按照8:1:1的比例划分为训练集、验证集和测试集。为提升模型对图像信息的特征提取能力,引入协调注意力机制,用以替代轻量型MobileNet V3模型的原始SE注意力机制,以提高矿物识别准确率。最后,采用迁移学习方法预训练CA-MobileNet V3模型,以加速模型收敛、提高泛化能力、避免过拟合。在训练过程中,将CA-MobileNet V3与mobilenet v3、MobileNet V3、ShuffleNet V2、Efficient Net V2等模型进行了性能比较。结果表明:各迁移模型均展现出显著的收敛速度优势,而CA-MobileNet V3矿物智能识别模型的Top1-准确率、Top2-准确率、f_1-score值分别达到93.90%、98.58%和93.89%,在所有模型中效果最佳,且模型大小仅为4.61 MB,属于轻量化模型。为验证模型有效性,t-SNE可视化分析被用于不同模型的识别效果比较,进一步印证了CA-MobileNet V3模型的优越性。 展开更多
关键词 矿物分类 迁移学习 轻量化模型 协调注意力机制 t-SNE
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乌梁素海湖冰完整生消过程的数值模拟
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作者 霍璞真 卢鹏 +3 位作者 解飞 王庆凯 李志军 ARVOLA Lauri 《水科学进展》 EI CAS CSCD 北大核心 2024年第1期145-155,共11页
为探究气候变暖背景下乌梁素海湖冰的冰厚、冰温和冰物候特征的变化,利用ERA5-Land和MERRA-2再分析数据作为大气强迫场,结合多源卫星遥感反演得到的初始模拟日期,通过一维高分辨率热力学雪冰(HIGHTSI)模型模拟了2015—2016年乌梁素海湖... 为探究气候变暖背景下乌梁素海湖冰的冰厚、冰温和冰物候特征的变化,利用ERA5-Land和MERRA-2再分析数据作为大气强迫场,结合多源卫星遥感反演得到的初始模拟日期,通过一维高分辨率热力学雪冰(HIGHTSI)模型模拟了2015—2016年乌梁素海湖冰的完整生消过程。结果显示:①研究期内,最大冰厚达到41.7 cm,初冰日和终冰日分别为2015年11月21日和2016年3月25日,冰期为126 d。②对于水深较浅而冬季日照充足的乌梁素海,气温是影响冰厚的主要因素,太阳辐射次之,两者的昼夜周期循环显著影响冰层的厚度和温度;当冰面有雪覆盖时,积雪的低导热和高反照率会明显削弱气温和太阳辐射对冰层的影响。③即使缺失现场观测数据,采用气象数据和遥感反演的初始模拟日期仍能准确地表征现场真实冰雪的完整演变过程。该研究可为中纬度干旱区季节性冰封浅水湖冰的计算和湖冰生消的年际变化研究奠定基础。 展开更多
关键词 湖冰 完整生消过程 再分析数据 卫星遥感 HIGHTSI模型 乌梁素海
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ESG表现、机构投资者持股与企业融资约束 被引量:3
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作者 谢柳芳 吕思捷 《兰州财经大学学报》 2024年第2期62-75,共14页
随着ESG投资理念的广泛传播和认同,企业ESG表现受到社会各界的关注。机构投资者作为资本市场的重要参与者,重视企业追求社会价值和经济价值相统一的绿色发展观念,将ESG表现纳入投资决策中,对降低企业内外部信息不对称,缓解企业融资约束... 随着ESG投资理念的广泛传播和认同,企业ESG表现受到社会各界的关注。机构投资者作为资本市场的重要参与者,重视企业追求社会价值和经济价值相统一的绿色发展观念,将ESG表现纳入投资决策中,对降低企业内外部信息不对称,缓解企业融资约束有积极的促进作用。基于2010—2021年度A股上市公司的相关数据,实证考察ESG表现对企业融资约束的影响,研究结果表明:一方面,企业的ESG表现具有价值创造功能,上市公司良好的ESG表现传递出积极的信号,降低企业经营风险,吸引机构投资者的投资,有助于缓解融资困难;另一方面,考虑异质性影响,压力抵抗型机构投资者相较于压力敏感型机构投资者具有更加长远的价值投资理念,良好的ESG表现更能够吸引压力抵抗型机构投资者的长期支持,改善企业的融资困境。研究结果有助于构建和完善中国ESG体系建设、鼓励企业提升ESG表现,培养市场中长期投资力量,推动完善ESG鉴证相关准则和标准,为投资者和相关政府监管部门的决策提供参考,推动企业高质量发展。 展开更多
关键词 ESG 机构投资者 融资约束
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基于主从博弈的燃气-太阳能-地热能耦合系统运行优化
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作者 李昌杰 陈玉柱 +3 位作者 秦方 李贤培 王军 Lund Peter 《太阳能学报》 EI CAS CSCD 北大核心 2024年第7期333-339,共7页
为提高能源利用率与经济性,提出一种基于博弈论中主从博弈的燃气-太阳能-地热能集成综合能源系统优化运行策略。首先建立综合能源系统模型,将其嵌套入博弈理论的框架下,建立主从博弈的运行优化模型,将能源聚合商作为领导者,综合能源系... 为提高能源利用率与经济性,提出一种基于博弈论中主从博弈的燃气-太阳能-地热能集成综合能源系统优化运行策略。首先建立综合能源系统模型,将其嵌套入博弈理论的框架下,建立主从博弈的运行优化模型,将能源聚合商作为领导者,综合能源系统和负荷终端用户作为跟随者,在各方追逐目标最优时实现经济性、环保性和节约性。最后通过算例验证了所提方法的有效性,聚合商、供能系统和终端用户均能实现最优的综合性能。 展开更多
关键词 电力负荷调度 分布式能源 博弈论 综合能源系统 运行优化
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消费者用药依从行为探析:基于两阶段理论模型
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作者 沈曼琼 廖建财 王海忠 《心理科学进展》 CSSCI CSCD 北大核心 2024年第5期859-872,共14页
个体健康行为改变是否存在阶段性是当前争议的焦点。用药依从行为作为关键的影响医疗效果指标,对个体的身心健康产生重要影响。前人对于用药依从水平的研究综述大多是从医学角度,着眼于特定疾病的用药依从行为。然而,在医疗保健行业市... 个体健康行为改变是否存在阶段性是当前争议的焦点。用药依从行为作为关键的影响医疗效果指标,对个体的身心健康产生重要影响。前人对于用药依从水平的研究综述大多是从医学角度,着眼于特定疾病的用药依从行为。然而,在医疗保健行业市场化的背景下,鲜有研究从消费者的视角出发,探究信息加工方式和心理过程对消费者用药依从行为的影响。同时,现有研究也缺乏对依从行为的理论分类和论述。基于两阶段理论模型回顾了营销领域影响消费者用药依从行为的影响因素,梳理了干预策略,并提出未来研究趋势与展望。在理论上,这有助于从健康行为改变阶段上理解个体的用药依从行为,丰富健康领域的阶段理论。在实践上有助于更好地理解消费者的心理健康和行为规律,并为慢性病管理提供了营销方面的启示。 展开更多
关键词 用药依从 消费者行为 医疗保健 行为干预
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基于注汞法的液冷花岗岩微观特性实验研究
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作者 尹土兵 苏巨振 +1 位作者 庄登登 李夕兵 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第1期169-181,共13页
在开采高温储层的过程中,微观特征变化重要影响深部热储层人工裂隙网络的建立。因此,研究该过程中微观特征的变化对深部地热能的安全高效开采具有重要意义。采用液体冷却(包括酸冷却和水冷却)处理高温花岗岩,模拟向高温储层注酸情况,以... 在开采高温储层的过程中,微观特征变化重要影响深部热储层人工裂隙网络的建立。因此,研究该过程中微观特征的变化对深部地热能的安全高效开采具有重要意义。采用液体冷却(包括酸冷却和水冷却)处理高温花岗岩,模拟向高温储层注酸情况,以获取相应条件下的花岗岩试样。随后,使用扫描电子显微镜-能量散射谱(SEM-EDS)和高压注汞法对样品进行测试。SEM-EDS结果显示,水冷却几乎不会影响元素的组成,酸冷却导致氧、硅和金属元素减少。在两种情况下,都观察到了孔隙和裂缝的形成。此外,与水冷却相比,酸冷却的样品表面更加不平整、疏松和粗糙。注汞法测试结果显示,随着处理温度的升高,液冷花岗岩样品的孔隙率、孔隙体积和比表面积有增加,但分形维数呈相反的趋势。研究结果表明,与水冷却相比,酸冷却条件对花岗岩的腐蚀作用使各项参数的变化更加显著,在酸冷却过程中产生更多的孔隙,提供更好的运输空间,使孔隙结构的复杂性降低。在高温储层的地热能有效提取方面,酸冷却具有更大应用潜力。 展开更多
关键词 孔隙结构 微观结构 液体冷却 土酸溶液 注汞法 花岗岩 分形理论
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高压电脉冲刺激对于热处理花岗岩影响的实验研究
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作者 尹土兵 刘程辉 +1 位作者 庄登登 李夕兵 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第5期1526-1541,共16页
高压电脉冲技术作为一种环保、可控、高效的破碎坚硬岩石的方法,其潜在应用场景值得进一步深入发掘。本文研究了高压电脉冲诱导干热岩产生预损伤和劣化方法的效果。对热处理后花岗岩薄片试样施加了不同峰值电压的高压电脉冲刺激,探讨了... 高压电脉冲技术作为一种环保、可控、高效的破碎坚硬岩石的方法,其潜在应用场景值得进一步深入发掘。本文研究了高压电脉冲诱导干热岩产生预损伤和劣化方法的效果。对热处理后花岗岩薄片试样施加了不同峰值电压的高压电脉冲刺激,探讨了高压电脉冲对于热处理花岗岩的影响。此外,还研究了初始温度对高压电脉冲刺激花岗岩的影响。结果表明:当外加峰值电压超过96 kV时,热处理花岗岩试样发生贯穿性的破裂,峰值电压越高,贯穿裂纹网络越复杂。当电压从96 kV增加到144kV时,花岗岩试样的微裂纹密度从8.63 mm/mm^(2)增加到13.26 mm/mm^(2)。随着热处理温度的升高,花岗岩发生电击穿的难度逐渐降低。在120 kV电脉冲放电刺激3次后,所有热处理温度高于400℃的花岗岩试样均能发生贯穿破裂。高压电脉冲刺激造成花岗岩产生的最大损伤发生在300~400℃的温度区间内。通过扫描电子显微镜观察到,随着试样处理温度的升高,内部孔隙和裂缝的发育情况逐渐加剧,孔隙大小、裂缝宽度和深度也随之增加。这项研究有望为建造干热岩人工储层提供新的见解。 展开更多
关键词 干热岩 高压电脉冲 破岩技术 温度 断裂模式 岩石结构
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Deformations at Earth’s dayside magnetopause during quasi-radial IMF conditions:Global kinetic simulations and Soft X-ray Imaging 被引量:2
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作者 ZhongWei Yang RiKu Jarvinen +7 位作者 XiaoCheng Guo TianRan Sun Dimitra Koutroumpa George K.Parks Can Huang BinBin Tang QuanMing Lu Chi Wang 《Earth and Planetary Physics》 EI CSCD 2024年第1期59-69,共11页
The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)is a joint mission of the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS).Primary goals are investigating the dynamic response of the Eart... The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)is a joint mission of the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS).Primary goals are investigating the dynamic response of the Earth's magnetosphere to the solar wind(SW)impact via simultaneous in situ magnetosheath plasma and magnetic field measurements,X-Ray images of the magnetosheath and magnetic cusps,and UV images of global auroral distributions.Magnetopause deformations associated with magnetosheath high speed jets(HSJs)under a quasi-parallel interplanetary magnetic field condition are studied using a threedimensional(3-D)global hybrid simulation.Soft X-ray intensity calculated based on both physical quantities of solar wind proton and oxygen ions is compared.We obtain key findings concerning deformations at the magnetopause:(1)Magnetopause deformations are highly coherent with the magnetosheath HSJs generated at the quasi-parallel region of the bow shock,(2)X-ray intensities estimated using solar wind h+and self-consistentO7+ions are consistent with each other,(3)Visual spacecraft are employed to check the discrimination ability for capturing magnetopause deformations on Lunar and polar orbits,respectively.The SMILE spacecraft on the polar orbit could be expected to provide opportunities for capturing the global geometry of the magnetopause in the equatorial plane.A striking point is that SMILE has the potential to capture small-scale magnetopause deformations and magnetosheath transients,such as HSJs,at medium altitudes on its orbit.Simulation results also demonstrate that a lunar based imager(e.g.,Lunar Environment heliospheric X-ray Imager,LEXI)is expected to observe a localized brightening of the magnetosheath during HSJ events in the meridian plane.These preliminary results might contribute to the pre-studies for the SMILE and LEXI missions by providing qualitative and quantitative soft X-ray estimates of dayside kinetic processes. 展开更多
关键词 collisionless shock SMILE mission FORESHOCK
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Empowering neuromorphic computing with topological states
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作者 Faisal Ahmed Zhipei Sun 《Journal of Semiconductors》 EI CAS CSCD 2024年第11期8-9,共2页
In 1980,scientist Klaus von Klitzing discovered the quantum Hall effect[1],a groundbreaking achievement that earned him the Nobel Prize in Physics in 1985.This discovery was a significant milestone in condensed matter... In 1980,scientist Klaus von Klitzing discovered the quantum Hall effect[1],a groundbreaking achievement that earned him the Nobel Prize in Physics in 1985.This discovery was a significant milestone in condensed matter physics,representing the first identification of topological quantum states. 展开更多
关键词 states. TOPOLOGICAL QUANTUM
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Performances of fissured red sandstone after thermal treatment with constant-amplitude and low-cycle impacts
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作者 Yongjun Chen Tubing Yin +3 位作者 P.G.Ranjith Xibing Li Qiang Li Dengdeng Zhuang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期561-587,共27页
In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic loads.In this paper,the dynamic behaviors and fracture characteristics of red sandston... In the engineering practices,it is increasingly common to encounter fractured rocks perturbed by temperatures and frequent dynamic loads.In this paper,the dynamic behaviors and fracture characteristics of red sandstone considering temperatures(25℃,200℃,400℃,600℃,and 800℃)and fissure angles(0°,30°,60°,and 90°)were evaluated under constant-amplitude and low-cycle(CALC)impacts actuated by a modified split Hopkinson pressure bar(SHPB)system.Subsequently,fracture morphology and second-order statistics within the grey-level co-occurrence matrix(GLCM)were examined using scanning electron microscopy(SEM).Meanwhile,the deep analysis and discussion of the mechanical response were conducted through the synchronous thermal analyzer(STA)test,numerical simulations,one-dimensional stress wave theory,and material structure.The multiple regression models between response variables and interactive effects of independent variables were established using the response surface method(RSM).The results demonstrate the fatigue strength and life diminish as temperatures rise and increase with increasing fissure angles,while the strain rate exhibits an inverse behavior.Furthermore,the peak stress intensification and strain rate softening observed during CALC impact exhibit greater prominence at increased fissure angles.The failure is dominated by tensile damage with concise evolution paths and intergranular cracks as well as the compressor-crushed zone which may affect the failure mode after 400℃.The second-order statistics of GLCM in SEM images exhibit a considerable dependence on the temperatures.Also,thermal damage dominated by thermal properties controls the material structure and wave impedance and eventually affects the incident wave intensity.The tensile wave reflected from the fissure surface is the inherent mechanism responsible for the angle effect exhibited by the fatigue strength and life.Ultimately,the peak stress intensification and strain rate softening during impact are determined by both the material structure and compaction governed by thermal damage and tensile wave. 展开更多
关键词 Red sandstone Temperature FISSURE Constant-amplitude and low-cycle(CALC) impact Fatigue failure Response surface method(RSM)
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Microscopic analysis on eukaryotic algae and cyanobacteria in nine seasonal lakes and ponds in Vestfjella,Dronning Maud Land,Antarctica
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作者 Lauri ARVOLA Matti LEPPÄRANTA LI Zhijun 《Advances in Polar Science》 CSCD 2024年第2期206-218,共13页
Antarctic continental lakes and ponds are among the most impoverished aquatic environments on earth but many of them support flourishing populations of cyanobacteria,eukaryotic algae,protozoans,and some multicellular ... Antarctic continental lakes and ponds are among the most impoverished aquatic environments on earth but many of them support flourishing populations of cyanobacteria,eukaryotic algae,protozoans,and some multicellular animals.In this study,we present results of a microscopic analysis of cyanobacteria and eukaryotic algae from nine diverse types of Antarctic continental water bodies during one austral summer.The results supplement and enlarge our previous studies on the limnological characteristics of the epiglacial and supraglacial lakes and ponds in Dronning Maud Land,an area that has received little attention from limnologists.The taxon with highest frequency among the samples(n=79)was Mesotaenium cf.berggrenii,a eukaryotic Zygnematophyceae,which occurred in 82%of the samples with a maximum cell density of 68 cells·mL^(-1).The taxa with second and third highest frequency were the prokaryotes Gloeocapsopsis(60%)and Leptolyngbya(41%),followed by Chlamydomonas(34%)and Cyanothece(29%).The number of taxa varied between 7-21 among the lakes and ponds,being highest in a supraglacial lake,and lowest in an epiglacial lake.The results did not reveal any obvious correlation between the abundance of any taxa and the water chemistry,but water bodies with inorganic sediments had higher cell densities and biomasses than those without sediment.This suggests the importance of sediment in supporting biological diversity in these ultraoligotrophic lakes and ponds. 展开更多
关键词 Antarctic continental lakes Antarctic continental ponds CYANOBACTERIA algae protozoa rotifers TARDIGRADA
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Influence of the Atlantic Multidecadal Oscillation and Interdecadal Pacific Oscillation on Antarctic surface air temperature during 1900 to 2015
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作者 Cuijuan Sui Lejiang Yu +2 位作者 Alexey YuKarpechko Licheng Feng Shan Liu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第3期48-58,共11页
The importance of the Atlantic Multidecadal Oscillation(AMO)and Interdecadal Pacific Oscillation(IPO)in influencing zonally asymmetric changes in Antarctic surface air temperature(SAT)has been established.However,prev... The importance of the Atlantic Multidecadal Oscillation(AMO)and Interdecadal Pacific Oscillation(IPO)in influencing zonally asymmetric changes in Antarctic surface air temperature(SAT)has been established.However,previous studies have primarily concentrated on examining the combined impact of the contrasting phases of the AMO and IPO,which have been dominant since the advent of satellite observations in 1979.This study utilizes long-term reanalysis data to investigate the impact of four combinations of+AMO+IPO,–AMO–IPO,+AMO–IPO,and–AMO+IPO on Antarctic SAT over the past 115 years.The+AMO phase is characterized by a spatial mean temperature amplitude of up to 0.5℃over the North Atlantic Ocean,accompanied by positive sea surface temperature(SST)anomalies in the tropical eastern Pacific and negative SST anomalies in the extratropical-mid-latitude western Pacific,which are indicative of the+IPO phase.The Antarctic SAT exhibits contrasting spatial patterns during the+AMO+IPO and+AMO–IPO periods.However,during the–AMO+IPO period,apart from the Antarctic Peninsula and the vicinity of the Weddell Sea,the entire Antarctic region experiences a warming trend.The most pronounced signal in the SAT anomalies is observed during the austral autumn,whereas the combination of–AMO and–IPO exhibits the smallest magnitude across all the combinations.The wavetrain excited by the SST anomalies associated with the AMO and IPO induces upper-level and surface atmospheric circulation anomalies,which alter the SAT anomalies.Furthermore,downward longwave radiation anomalies related to anomalous cloud cover play a crucial role.In the future,if the phases of AMO and IPO were to reverse(AMO transitioning to a negative phase and IPO transitioning to a positive phase),Antarctica could potentially face more pronounced warming and accelerated melting compared to the current observations. 展开更多
关键词 Atlantic Multidecadal Oscillation(AMO) Interdecadal Pacific Oscillation(IPO) surface air temperature ANTARCTIC wavetrain Rossby wave source
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Recent advances in studies on changes in Arctic sea ice microstructure and implications to thermodynamic modeling
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作者 LU Peng YU Miao +3 位作者 WANG Lei Bin CHENG WANG Qingkai LI Zhijun 《Advances in Polar Science》 CSCD 2024年第3期281-288,共8页
The study of Arctic sea ice has traditionally been focused on large-scale such as reductions of ice coverage,thickness,volumes and sea ice regime shift.Research has primarily concentrated on the impact of large-scale ... The study of Arctic sea ice has traditionally been focused on large-scale such as reductions of ice coverage,thickness,volumes and sea ice regime shift.Research has primarily concentrated on the impact of large-scale external factors such as atmospheric and oceanic circulations,and solar radiation.Additionally,Arctic sea ice also undergoes rapid micro-scale evolution such as gas bubbles formation,brine pockets migration and massive formation of surface scattering layer.Field studies like CHINARE(2008-2018)and MOSAiC(2019-2020)have confirmed these observations,yet the full understanding of those changes remain insufficient and superficial.In order to cope better with the rapidly changing Arctic Ocean,this study reviews the recent advances in the microstructure of Arctic sea ice in both field observations and laboratory experiments,and looks forward to the future objectives on the microscale processes of sea ice.The significant porosity and the cyclical annual and seasonal shifts likely modify the ice's thermal,optical,and mechanical characteristics,impacting its energy dynamics and mass balance.Current thermodynamic models,both single-phase and dual-phase,fail to accurately capture these microstructural changes in sea ice,leading to uncertainties in the results.The discrepancy between model predictions and actual observations strongly motivates the parameterization on the evolution in ice microstructure and development of next-generation sea ice models,accounting for changes in ice crystals,brine pockets,and gas bubbles under the background of global warming.It helps to finally achieve a thorough comprehension of Arctic sea ice changes,encompassing both macro and micro perspectives,as well as externaland internal factors. 展开更多
关键词 ARCTIC sea ice MICROSTRUCTURE THERMODYNAMICS numerical models
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Al^(3+) doped CeO_(2) for proton conducting fuel cells
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作者 Sarfraz Shahzad Rasool +6 位作者 Muhammad Khalid MAKYousaf Shah Bin Zhu Jung-Sik Kim Muhammad Imran Asghar Nabeela Akbar Wenjing Dong 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第10期2253-2262,共10页
Developing high ionic conducting electrolytes is crucial for applying proton-conducting fuel cell(PCFCs)practically.The cur-rent study investigates the effect of alumina on the structural,morphological,electrical,and ... Developing high ionic conducting electrolytes is crucial for applying proton-conducting fuel cell(PCFCs)practically.The cur-rent study investigates the effect of alumina on the structural,morphological,electrical,and electrochemical properties of CeO_(2).Lattice oxygen vacancies are induced in CeO_(2) by a general doping concept that enables fast ionic conduction at low-temperature ranges(300-500℃)for PCFCs.Rietveld refinement of the X-ray diffraction(XRD)patterns established the pure cubic fluorite structure of Al-doped CeO_(2)(ADC)samples and confirmed Al ions’fruitful integration in the CeO_(2) lattice.The electronic structure of the alumina-doped ceria of the materials(10ADC,20ADC,and 30ADC)has been investigated.As a result,it was found that the best composition of 30ADC-based electrolytes induced maximum lattice oxygen vacancies.The corresponding PCFC exhibited a maximum power output of 923 mW/cm^(2)at 500℃.Moreover,the investigation proves the proton-conducting ability of alumina-doped ceria-based fuel cells by using an oxide ion-blocking layer. 展开更多
关键词 proton ceramic fuel cells oxygen vacancies higher fuel cell performance DOPING fast ions transportation
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A critical review of direct laser additive manufacturing ceramics
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作者 Dake Zhao Guijun Bi +4 位作者 Jie Chen WaiMeng Quach Ran Feng Antti Salminen Fangyong Niu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第12期2607-2626,共20页
The urgent need for integrated molding and sintering across various industries has inspired the development of additive manu-facturing(AM)ceramics.Among the different AM technologies,direct laser additive manufacturin... The urgent need for integrated molding and sintering across various industries has inspired the development of additive manu-facturing(AM)ceramics.Among the different AM technologies,direct laser additive manufacturing(DLAM)stands out as a group of highly promising technology for flexibly manufacturing ceramics without molds and adhesives in a single step.Over the last decade,sig-nificant and encouraging progress has been accomplished in DLAM of high-performance ceramics,including Al_(2)O_(3),ZrO_(2),Al_(2)O_(3)/ZrO_(2),SiC,and others.However,high-performance ceramics fabricated by DLAM face challenges such as formation of pores and cracks and resultant low mechanical properties,hindering their practical application in high-end equipment.Further improvements are necessary be-fore they can be widely adopted.Methods such as field-assisted techniques and post-processing can be employed to address these chal-lenges,but a more systematic review is needed.This work aims to critically review the advancements in direct selective laser sintering/melting(SLS/SLM)and laser directed energy deposition(LDED)for various ceramic material systems.Additionally,it provides an overview of the current challenges,future research opportunities,and potential applications associated with DLAM of high-perform-ance ceramics. 展开更多
关键词 3D printing laser additive manufacturing CERAMICS QUALITY microstructure mechanical properties
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新型研究型大学的实践创新、运行机制与可持续发展
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作者 蔡三发 陈旭琪 田少艾 《科教发展研究》 2024年第1期18-33,共16页
新一轮科技革命浪潮下,为进一步实现高水平科技自立自强目标,传统研究型大学迫切需要转型升级。在此背景下,新型研究型大学的概念与实践引起了广泛关注。新型研究型大学究竟有何特别之处?又该如何实现可持续发展?文章旨在深入探讨新型... 新一轮科技革命浪潮下,为进一步实现高水平科技自立自强目标,传统研究型大学迫切需要转型升级。在此背景下,新型研究型大学的概念与实践引起了广泛关注。新型研究型大学究竟有何特别之处?又该如何实现可持续发展?文章旨在深入探讨新型研究型大学的内涵,并从时代特征、办学规模、学科发展、科技创新以及社会影响五大维度比较新型研究型大学与传统研究型大学、新兴研究型大学的差异,进而辨析新型研究型大学究竟“新”在何处。同时,结合我国新型研究型大学在具体实践中的创新探索,总结了新型研究型大学四大实现形式和六大利益主体相互作用的运行机制。进一步地,论文探讨了保障新型研究型大学可持续发展的关键策略,包括教学、科研、社会参与以及履行这三大职能的组织管理过程四方面。研究不仅为理解新型研究型大学提供了理论支持,同时也为相关政策制定和实践创新提出了有益的建议。 展开更多
关键词 新型研究型大学 实践创新 运行机制 利益主体 可持续发展
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The ALMA-QUARKS Survey.Ⅱ.The ACA 1.3 mm Continuum Source Catalog and the Assembly of Dense Gas in Massive Star-Forming Clumps
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作者 许峰玮 Ke Wang +30 位作者 Tie Liu Lei Zhu Guido Garay Xunchuan Liu Paul Goldsmith Qizhou Zhang Patricio Sanhueza Shengli Qin Jinhua He Mika Juvela Anandmayee Tej Hongli Liu Shanghuo Li Kaho Morii Siju Zhang Jianwen Zhou Amelia Stutz Neal JEvans Kee-Tae Kim Shengyuan Liu Diego Mardones Guangxing Li Leonardo Bronfman Ken’ichi Tatematsu Chang Won Lee Xing Lu Xiaofeng Mai Sihan Jiao James O.Chibueze Keyun Su Viktor L.Tóth 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期119-139,共21页
Leveraging the high resolution,sensitivity,and wide frequency coverage of the Atacama Large Millimeter/submillimeter Array(ALMA),the QUARKS survey,standing for“Querying Underlying mechanisms of massive star formation... Leveraging the high resolution,sensitivity,and wide frequency coverage of the Atacama Large Millimeter/submillimeter Array(ALMA),the QUARKS survey,standing for“Querying Underlying mechanisms of massive star formation with ALMA-Resolved gas Kinematics and Structures”,is observing 139 massive starforming clumps at ALMA Band 6(λ~1.3 mm).This paper introduces the Atacama Compact Array(ACA)7 m data of the QUARKS survey,describing the ACA observations and data reduction.Combining multiwavelength data,we provide the first edition of QUARKS atlas,offering insights into the multiscale and multiphase interstellar medium in high-mass star formation.The ACA 1.3 mm catalog includes 207 continuum sources that are called ACA sources.Their gas kinetic temperatures are estimated using three formaldehyde transitions with a non-LTE radiation transfer model,and the mass and density are derived from a dust emission model.The ACA sources are massive(16–84 percentile values of 6–160 M_(⊙)),gravity-dominated(M∝R^(1.1))fragments within massive clumps,with supersonic turbulence(M>1)and embedded star-forming protoclusters.We find a linear correlation between the masses of the fragments and the massive clumps,with a ratio of 6%between the two.When considering fragments as representative of dense gas,the ratio indicates a dense gas fraction(DGF)of 6%,although with a wide scatter ranging from 1%to 10%.If we consider the QUARKS massive clumps to be what is observed at various scales,then the size-independent DGF indicates a self-similar fragmentation or collapsing mode in protocluster formation.With the ACA data over four orders of magnitude of luminosity-to-mass ratio(L/M),we find that the DGF increases significantly with L/M,which indicates clump evolutionary stage.We observed a limited fragmentation at the subclump scale,which can be explained by a dynamic global collapse process. 展开更多
关键词 stars:formation ISM:kinematics and dynamics ISM:clouds stars:protostars
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均相和非均相催化微藻脂质提取和酯交换制备生物燃料的研究进展
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作者 Vinoth Kumar Ponnumsamy Hussein E.Al-Hazmi +9 位作者 Sutha Shobana Jeyaprakash Dharmaraja Dipak Ashok Jadhav Rajesh Banu J Grzegorz Piechota Bartłomiej Igliński Vinod Kumar Amit Bhatnagar Kyu-Jung Chae Gopalakrishnan Kumar 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第4期97-117,共21页
随着化石燃料燃烧导致的二氧化碳排放不断加剧气候变化,且化石燃料储量日益减少,寻求可再生能源已成为一项紧迫的任务.其中,藻类衍生可持续燃料因具有成本优势和可运输性,在解决全球能源危机方面展现出广阔前景,备受关注.利用化学转化... 随着化石燃料燃烧导致的二氧化碳排放不断加剧气候变化,且化石燃料储量日益减少,寻求可再生能源已成为一项紧迫的任务.其中,藻类衍生可持续燃料因具有成本优势和可运输性,在解决全球能源危机方面展现出广阔前景,备受关注.利用化学转化技术从微藻中提取脂质,并通过酯交换反应可以将其转化为脂肪酸甲酯,是生产绿色生物燃料的有效途径.这一过程涉及游离脂肪酸、磷脂和甘油三酯的提取,并且生产过程能耗低,成为满足日益增长的能源需求的一种理想解决方案.本文综述了微藻脂质提取和酯交换制备生物燃料的相关研究进展.首先,介绍了微藻脂质的提取方法,包括溶剂提取法、索氏提取法、布利格和戴耶法、超临界二氧化碳提取以及离子液体溶剂法等,并分析了各方法的优缺点.随后,重点阐述了酯交换技术在微藻脂质转化中的应用,包括酸碱催化、酶催化以及原位酯交换反应等,并探讨了这些技术的反应机理、催化剂选择、反应器设计以及生物油生产工艺等方面的研究进展.通过综述上述研究进展,为微藻脂质的生产和应用提供了理论指导.研究表明,通过优化催化剂种类、反应条件以及提取方法,可以有效提高微藻脂质的转化效率和生物油品质.同时,本文也指出了当前微藻脂质生产中面临的挑战,如微藻栽培和生长条件优化、高效转化技术的开发等.随着可持续能源日益受到重视,微藻脂质作为一种可再生能源具有巨大的发展潜力.未来研究应进一步关注微藻的规模化栽培、生长条件优化以及高效转化技术的研发,以提高微藻脂质的产量和品质.同时,应进一步推动和实现微藻生物燃料的实际应用,从而为应对气候变化和能源危机提供有效的解决方案. 展开更多
关键词 微藻 脂质提取 酯交换 催化 酶催化 原位技术
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