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Methane and Nitrous Oxide Emissions from Three Paddy Rice Based Cultivation Systems in Southwest China

Advances in Atmospheric Sciences 2006年第3期23卷 415-424页

作者：江长胜王跃思郑循华朱波黄耀郝庆菊 institute of Atmospheric Physics institute of mountain Hazards and Environment

To understand methane （CH4） and nitrous oxide （N2O） emissions from permanently flooded rice paddy fields and to develop mitigation options, a field experiment was conducted in situ for two years （from late 2002 to early 2005） in three rice-based cultivation systems, which are a permanently flooded rice field cultivated with a single time and followed by a non-rice season （PF）, a rice-wheat rotation system （RW） and a rice-rapeseed rotation system （RR） in a hilly area in Southwest China. The results showed that the total CH4 emissions from PF were 646.3±52.1 and 215.0±45.4 kg CH4 hm^-2 during the rice-growing period and non-rice period, respectively. Both values were much lower than many previous reports from similar regions in Southwest China. The CH4 emissions in the rice-growing season were more intensive in PF, as compared to RW and RR. Only 33% of the total annual CH4 emission in PF occurred in the non-rice season, though the duration of this season is two times longer than the rice season. The annual mean N2O flux in PF was 4.5±0.6 kg N2O hm^-2 yr^-1. The N2O emission in the rice-growing season was also more intensive than in the non-rice season, with only 16% of the total annual emission occurring in the non-rice season. The amounts of N2O emission in PF were ignorable compared to the CH4 emission in terms of the global warming potential （GWP）. Changing PF to RW or RR not only eliminated CH4 emissions in the non-rice season, but also substantially reduced the CH4 emission during the following rice-growing period （ca. 58%, P〈0.05）. However, this change in cultivation system substantially increased N2O emissions, especially in the non-rice season, by a factor of 3.7 to 4.5. On the 100-year horizon, the integrated GWP of total annual CH4 and N2O emissions satisfies PF〉〉RR≈RW. The GWP of PF is higher than that of RW and RR by a factor of 2.6 and 2.7, respectively. Of the total GWP of CH4 and N2O emissions, CH4 emission contributed to 93%, 65% and 59% in PF, RW and

关键词： cultivation systems permanently flooded rice fields CH4 N2O global warming potential (GWP)

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Graphene Aerogel Composites with Self‑Organized Nanowires‑Packed Honeycomb Structure for highly Efficient Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第2期17卷 533-547页

作者： Xiao You Huiying Ouyang Ruixiang Deng Qiuqi Zhang Zhenzhong Xing Xiaowu Chen Qingliang Shan Jinshan Yang Shaoming Dong State Key Laboratory of high Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Key Laboratory of Inorganic Coating Materials CAS Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Structural Ceramics and Composites Engineering Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049People’s Republic of China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210People’s Republic of China School of Materials Science and Engineering Zhejiang Sci-Tech UniversityHangzhou 310018People’s Republic of China University of Chinese Academy of Sciences Beijing 100039People’s Republic of China

With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave ***,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss *** macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene *** unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric ***,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 ***,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.

关键词： Hierarchical porous structure Interface high-temperature resistance Graphene aerogel composites Electromagnetic wave absorption

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Temporal stability of aboveground net primary production in northern Tibet alpine steppe in response to nitrogen addition

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Journal of mountain Science 2019年第11期16卷 2679-2686页

作者： WU Jian-bo WANG Xiao-dan Key Laboratory of mountain Environment Evolution and Ecological Regulation Institute of Mountain Hazard and Environment CAS

The mechanism that sustains the temporal stability of aboveground net primary production(ANPP)respond to nitrogen deposition is still ***,we investigated the mechanism of temporal stability of ANPP through the effect of N addition on diversity,species asynchrony andportfolio effects in northern Tibet alpine steppe over a period of three *** results showed that the community temporal stability did not significantly correlate with the species richness and Shannon–Wiener *** asynchrony and stability was also not significantly affected by N addition(p>0.05).Furthermore,there was no significant relationship between species asynchrony and temporal *** the value of portfolio effects(z)(z=1.304,95%confidence intervals:1.029–1.597)was more than 1,the portfolio effects was not a primary driver of temporal stability due to the biodiversity being *** above results suggested that the richness,species asynchrony and portfolio effect could not support for mechanism of stability at the alpine *** the results of path analysis,species temporal stability positively supports the community temporal stability in the alpine steppe *** to the character of environment and vegetation of alpine steppe at North Tibet,we inferred that dominance species stability is more important than species richness for the community temporal stability.

关键词： Community temporal stability Species richness Species asynchrony Species temporal stability Portfolio effects Nitrogen deposition

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Record-breaking bifunctional oxygen electrocatalyst accomplished by a data-driven approach for zinc-air batteries

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Journal of Energy Chemistry 2025年第1期100卷 144-145页

作者： Deviprasath Chinnadurai Zhi Wei Seh institute of Materials Research and Engineering (IMRE) Agency for Science Technology and Research (A*STAR)

Rechargeable zinc-air batteries(ZABs) have recently drawn great attention in energy research due to their high theoretical capacity,low costs, and inherently safe nature [1–3]. However, the sluggish cathode reactions necessitate the development of bifunctional oxygen electrocatalysts with lower ΔE indicator values. The ΔE indicator is commonly employed to quantitatively evaluate the electrocatalytic activity of a bifunctional oxygen electrocatalyst,representing the overall overpotential from oxygen reduction reaction(ORR) to oxygen evolution reaction(OER).

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Experimental study of debris flow caused by domino failures of landslide dams

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International Journal of Sediment Research 2014年第3期29卷 414-422页

作者： Hua-Yong CHEN Peng CUI Gordon G.D.ZHOU Xing-Hua ZHU Jin-Bo TANG Key Laboratory of mountain Hazards and Earth Surface Process CAS institute of mountain Hazards and Environment CAS

The formation of landslide dams is often induced by earthquakes in mountainous *** failure of a landslide dam typically results in catastrophic flash floods or debris flows *** attention has been given to the processes and mechanisms involved in the failure of individual landslide ***,the processes leading to domino failures of multiple landslide dams remain *** this study,experimental tests were carried out to investigate the domino failure of landslide dams and the consequent enlargement of downstream debris *** blockage conditions were considered,including complete blockage,partial blockage and erodible bed(no blockage).The mean velocity of the flow front was estimated by *** stress transducers(TSTs)and Laser range finders(LRFs) were employed to measure the total stress and the depth of the flow front,*** a complete blockage pattern,a portion of the debris flow was trapped in front of each retained landslide dam before the latter collapsed *** was accompanied by a dramatic decrease in the mean velocity of the flow ***,under both partial blockage and erodible bed conditions,the mean velocity of the flow front increased gradually downward along the sloping *** failures of the landslide dams were triggered when a series of dams(complete blockage and partial blockage) were distributed along the ***,not all of these domino failures led to enlarged debris *** modes of dam failures have significant impacts on the enlargement of debris ***,further research is necessary to understand the mechanisms of domino failures of landslide dams and their effects on the enlargement of debris flows.

关键词： Debris flow Landslide dams Domino failures Enlargement of debris flow Mean velocity

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Particle image velocimetry measurements of vortex structures in stilling basin of multi-horizontal submerged jets

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Journal of Hydrodynamics 2013年第4期25卷 556-563页

作者：陈剑刚张建民许唯临栗帅何小泷 State Key Laboratory of Hydraulics and mountain River Engineering Sichuan University institute of mountain Hazards and Environment Chinese Academy of Sciences

Measurements of turbulent flow fields in a stilling basin of multi-horizontal submerged jets were made with the single- camera Particle Image Velocimetry （PIV）. The particle images were captured, processed, and subsequently used to characterize the flow in terms of the 2-D velocity and vorticity distributions. This study shows that the maximum close-to-bed velocity in the stilling basin is approximately reduced by 60%, comparing to the jet velocity at the outlet of orifices. The jet velocity is distributed evenly at the latter half of the stilling basin and the time-averaged velocity of the cross section is reduced by 77%-85%, comparing to the jet velocity at the outlet of orifices. These results show that the vortices with horizontal axes are continuously repeated during the form-merge-split-disappear process. The vertical vortices are continuously formed and disappeared, they appear randomly near the slab and intermittently reach the slab of the stilling basin. The range of these vortices is small. Vortices with horizontal axes and ver- tical vortices do not coincide in space and the vortices with horizontal axes only affect the position of the tail of the vertical vortices attached to the slab of the stilling basin.

关键词： multi-horizontal submerged jets Particle Image Velocimetry (PIV) vortex structure stilling basin hydraulic jump

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Real-time fault detection method based on belief rule base for aircraft navigation system

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Chinese Journal of Aeronautics 2013年第3期26卷 717-729页

作者： Zhao Xin Wang Shicheng Zhang Jinsheng Fan Zhiliang Min Haibo high-Tech institute of Xi'an

Real-time and accurate fault detection is essential to enhance the aircraft navigation system’s reliability and safety. The existent detection methods based on analytical model draws back at simultaneously detecting gradual and sudden faults. On account of this reason, we propose an online detection solution based on non-analytical model. In this article, the navigation system fault detection model is established based on belief rule base （BRB）, where the system measuring residual and its changing rate are used as the inputs of BRB model and the fault detection function as the output. To overcome the drawbacks of current parameter optimization algorithms for BRB and achieve online update, a parameter recursive estimation algorithm is presented for online BRB detection model based on expectation maximization （EM） algorithm. Furthermore, the proposed method is verified by navigation experiment. Experimental results show that the proposed method is able to effectively realize online parameter evaluation in navigation system fault detection model. The output of the detection model can track the fault state very well, and the faults can be diagnosed in real time and accurately. In addition, the detection ability, especially in the probability of false detection, is superior to offline optimization method, and thus the system reliability has great improvement.

关键词： Belief rule base Fault detection Fault tolerant control Integrated navigation Parameter recursive estimation algorithm

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Energetics and diffusion of point defects in Au/Ag metals:A molecular dynamics study

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Chinese Physics B 2019年第8期28卷 95-104页

作者： Zhi-Yong Liu Bin He Xin Qu Li-Bo Niu Ru-Song Li Fei Wang Xi’an high Technology institute

To reveal the potential aging mechanism for self-irradiation in Pu-Ga alloy,we choose Au-Ag alloy as its substitutional material in terms of its mass density and lattice *** a first step for understanding the microscopic behavior of point defects in Au-Ag alloy,we perform a molecular dynamics(MD)simulation on energetics and diffusion of point defects in Au and Ag *** results indicate that the octahedral self-interstitial atom(SIA)is more stable than the tetrahedral *** stability sequence of point defects for He atom in Au/Ag is:substitutional site>octahedral interstitial site>tetrahedral interstitial *** He-V cluster(Hen Vm,V denotes vacancy)is the most stable at n=*** the mono-vacancy diffusion,the MD calculation shows that the first nearest neighbour(1 NN)site is the most favorable site on the basis of the nudged elastic band(NEB)calculation,which is in agreement with previous experimental *** are two peaks for the second nearest neighbour(2 NN)and the third nearest neighbour(3 NN)diffusion curve in octahedral interstitial site for He atom,indicating that the 2 NN and 3 NN diffusion for octahedral SIA would undergo an intermediate defect structure similar to the 1 NN *** 3 NN diffusion for the tetrahedral SIA and He atom would undergo an intermediate site in analogy to its initial *** diffusion of point defects,the vacancy,SIA,He atom and He-V cluster may have an analogous effect on the diffusion velocity in Ag.

关键词： interatomic potential radiation damage point defect diffusion barrier

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An Empirical Formula for Suspended Sediment Delivery Ratio of Main River after Confluence of Debris flow

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Journal of mountain Science 2013年第2期10卷 326-336页

作者： ZHANG Jin-shan CUI Peng Key Laboratory of mountain Hazard and Surface Process Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences

In order to calculate the suspended sediment discharge of the flood debris flows into the main river,a small scale flume test was designed to simulate the process of confluence of Jiangjia Ravine and Xiangjiang River in Yunnan province,*** test observation and data analysis,suspended sediment discharge of Debris flow after its entry into the main river was found to have a close relation with the bulk density,the confluence angle of the Debris flow and the main river,the ratio between per unit width discharge of Debris flow and main *** on the measured and simulated results,and statistical analysis,an empirical formula was proposed for the suspended SDR(Sediment Delivery Ratio) of the main river after the confluence of Debris *** with the observed results of Debris flow in 2009,the error between the data calculated by the empirical formula and the monitored data is only about 10%.

关键词： Debris flow Confluence SuspendedSediment Delivery Ratio (SDR) Jiangjia Ravine Xiaojiang River Model

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Causes for the Unimodal Pattern of Leaf Carbon Isotope Composition in Abies faxoniana Trees Growing in a Natural Forest along an Altitudinal Gradient

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Journal of mountain Science 2015年第1期12卷 39-48页

作者： ZHAO Hong-xia DUAN Bao-li LEI Yan-bao Key Laboratory of mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences

Leaf morphological and physiological traits of Abies faxoniana growing in a natural forest along an altitudinal gradient were measured with the aim to identify the central mechanism for the marked variation in foliar δ13C determined by an isotope ratio mass spectrometer. There is a unimodal pattern of plant functional traits in these temperate and semi- humid areas. Stomatal parameters, specific leaf area, and C/N ratio increased, whereas C, N and δ13C values decreased with increasing altitude below 3000 m a.s.1. In contrast, they exhibited opposite trends above 3000 m a.s.l.. Our results demonstrated that high-altitude plants achieve higher water use efficiency （WUE） at the expense of decreasing nitrogen use efficiency （NUE）, whereas plants at 3000 m can maintain a relatively higher NUE but a lower WUE. Such intra-specific differences in the trade-off between NUE and WUE may partially explain the altitudinal distribution of the plants in relation to moisture and nutrient availability. Our results clearly indicate that the functional relations between nutritional status and the structure of leaves are responsible for the altitudinal variations associated with δ13C. The pivotal role of specific leaf area in regulating plant adaptive responses provides a potential physiological mechanism for the observed growth advantage of populations occupying the medium altitude. These adaptive responses altitudinal gradients showed that an altitude to of approximately 3000 m a.s.1, is the optimum distribution zone for A. faxoniana, allowing the most vigorous growth and metabolism. These results improve our understanding of the various roles of environmental and biotic variables upon δ13C dynamics and provide useful information for subalpine coniferous forest management.

关键词： Abiesfaxoniana Age Altitude Carbonisotope ratio Nitrogen content

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