Secondary emission of electrons from molybdenum

The ratio of the number of secondary electrons to primary electrons of various energies incident on a molybdenum plate (previously subjected to severe heat treatment) was measured. The results obtained resemble those reported by Petry more closely than they do the more recent work of Hyatt and Smith. Possibilities for explaining discrepancies are suggested.     

Crystal face dependent intrinsic wettability of metal oxide surfaces

Knowledge of intrinsic wettability at solid/liquid interfaces at the molecular level perspective is significant in understanding crucial progress in some fields, such as electrochemistry, molecular biology and earth science. It is generally believed that surface wettability is determined by the surface chemical component and surface topography. However, when taking molecular structures and interactions into consideration, many intriguing phenomena would enrich or even redress our understanding of surface wettability. From the perspective of interfacial water molecule structures, here, we discovered that the intrinsic wettability of crystal metal oxide is not only dependent on the chemical components but also critically dependent on the crystal faces. For example, the crystal face of α-Al₂O₃ is intrinsically hydrophobic with a water contact angle near 90°, while another three crystal faces are intrinsically hydrophilic with water contact angles <65°. Based on surface energy analysis, it is found that the total surface energy, polar component and Lewis base portion of the hydrophobic crystal face are all smaller than the other three hydrophilic crystal faces indicating that they have different surface states. DFT simulation further revealed that the adsorbed interfacial water molecules on each crystal face hold various orientations. Herein, the third crucial factor for surface wettability from the perspective of the molecular level is presented, that is the orientations of adsorbed interfacial water molecules apart from the macro-level chemical component and surface topography. This study may serve as a source of inspiration for improving wetting theoretical models and designing controllable wettability at the molecular/atomic level.     

自然湿地甲烷排放时空变化规律研究（英文）

对三江平原沼泽湿地甲烷排放时空变化规律及其影响因素进行了研究。自然湿地甲烷排放存在着明显的季节性变化，即随着植物生长甲烷排放量不断增加，在8月未达到最大值，而后下降。这一变化特点主要受温度和沼泽静水层深度所控制。春季低温不仅直接降低了甲烷的产生强度，而且也降低了其它好氧微生物的活性，使得沼泽水中存留较多的氧气，这些氧气直接加速了沼泽水中甲烷氧化，同时又提高了沼泽水的氧化还原电位，后者反过来进一步减缓甲烷的产生。三江平原不同植被生长的沼泽甲烷排放通量呈如下特点：毛果苔草>乌拉苔草>小叶章。莎草科植物生长的沼泽中，72-86%的甲烷通过植物排放进入大气，而小叶章生长的沼泽只有28-31%。毛果苔草促进了沼泽水中甲烷的氧化而不是产生，相反小叶章通过释放根系分泌物刺激甲烷产生的能力大于分泌氧气促进甲烷氧化的能力。毛果苔草沼泽水中更高的甲烷浓度是由于深的静水层淹没更多的植物立枯，从而为产甲烷菌提供充足的底物所致。     

基于消费者视角的碳排放权交易机制研究

消费者因素对碳排放具有重要影响,加强消费行为的引导、激励,形成低碳消费模式,具有重要理论和现实意义。本文基于消费者视角,运用产权理论和外部性理论,建立了消费排放权交易的理论框架,研究了消费排放权交易对个人、社会福利以及消费者选择的影响,研究认为消费排放权交易属于帕累托次优解,据此提出了一个将消费者纳入减排行动的减排机制。     

中国稻田温室气体的排放与减排

中国是世界上最大的水稻生产国, 水稻种植面积占全球总种植面积的30%。水稻生产在粮食安全方面起着重要的作用, 稻田却是温室气体甲烷(CH₄)和氧化亚氮(N₂O)的重要排放源。文章综述了稻田CH₄和N₂O的产生过程、影响因素及时空变异规律, 总结了近年来我国稻田CH₄和N₂O排放总量的估算结果, 并提出了针对性的温室气体减排措施。     

稻田甲烷排放非连续测量中采样时间的选择

稻田甲烷排放的测量分为手动采样和自动采样两种方法,在非连续的手动采样观测方法中,采样频度和采样时间的选择极为重要．根据实验总结出稻田甲烷的排放有接近正弦曲线的日变化规律．采样时间选在９００～１１００和２１００～２３００时的误差最小