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放牧牲畜粪尿返还对季节性冻融高寒草原N_(2)O排放的影响

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草地学报 2024年第6期32卷 1843-1855页

作者：熊朝阳张青松李佳秀杜静曹颖张雪汪爽杜子银西华师范大学地理科学学院四川南充637009 四川省金堂实验中学四川成都610400 中国科学院、水利部成都山地灾害与环境研究所中国科学院申扎高寒草原与湿地生态系统观测试验站四川成都610299

放牧牲畜粪尿斑块是草地氧化亚氮(N_(2)O)排放的热点区域,季节性冻融会不同程度改变粪尿养分返还效率和土壤特性,使粪尿作用下的土壤N2O排放特性复杂且作用机理尚不明确。本文采用静态箱-气相色谱法开展为期1年的野外控制试验,探究牦牛... 详细信息

放牧牲畜粪尿斑块是草地氧化亚氮(N_(2)O)排放的热点区域,季节性冻融会不同程度改变粪尿养分返还效率和土壤特性,使粪尿作用下的土壤N2O排放特性复杂且作用机理尚不明确。本文采用静态箱-气相色谱法开展为期1年的野外控制试验,探究牦牛和藏绵羊粪尿处理对季节性冻融藏北高寒草原土壤氮动态及N_(2)O排放通量的影响和可能的作用机制。结果表明:尿液施加对土壤N2O排放的短期促进作用明显,且均在处理第1天达到排放通量峰值;牦牛粪尿施加对土壤矿化氮含量的增加更为突出,且牛粪和牛尿处理N_(2)O年累积排放量显著高于羊粪和羊尿处理(P<0.05);冻融期各处理N_(2)O累积排放量占全年的比例为29.3%~42.4%,且消融期对非生长季的贡献最大。研究结论有助于为优化牲畜排泄物管理模式和促进季节性冻融高寒草地温室气体减排等提供理论参考。

关键词：冻融作用粪便降解硝化反硝化 N_(2)O排放高寒草原藏北高原

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Short-term effects of yak and Tibetan sheep urine deposition on soil carbon and nitrogen concentrations in an alpine steppe of the northern Tibetan Plateau, China

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Journal of Mountain Science 2022年第4期19卷 1156-1167页

作者： du zi-yin WANG Xiao-dan CAI Yan-jiang School of Geographical Sciences China West Normal UniversityNanchong 637009China Xainza Alpine Steppe and Wetland Ecosystem Observation Station Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences&Ministry of Water ResourcesChengdu 610041China College of Environmental and Resource Sciences Zhejiang A&F UniversityHangzhou 311300China

Yak(Bos grunniens) and Tibetan sheep urine deposited onto the alpine grasslands of the Qinghai-Tibetan Plateau is an important pathway for nutrient return, and it is closely related to soil fertility and alpine grassland productivity. However, hitherto, few studies have reported the effects of yak and Tibetan sheep urine deposition on soil carbon(C) and nitrogen(N) concentrations and the possible functional mechanisms under field conditions in alpine grasslands. To explore the status of soil C and N responding to the immediate N addition from livestock urine, we conducted a 28-d field experiment with three treatments, which include the application of yak urine(YU) and Tibetan sheep urine(TSU) application, and the control(CK, no application of urine). The results showed that YU treatment increased the soil moisture content and p H at 0-10 cm across the 28-day experimental period. Urine application resulted in the fluctuation of soil organic C(SOC) and increased topsoil SOC concentration during the middle and later periods of the experiment. Application of YU evidently increased the soil total N(TN) concentration in the 0-10 cm layer, while it did not affect the SOC concentrations in the 10-20 and 20-30 cm layers. Compared with the control, YU treatment significantly(P<0.05) increased the 0-10 and 10-20 cm soil ammonium-N(NH;-N) concentration throughout the 28 days, while the TSU treatment significantly(P<0.05) increased the 0-10 and 10-20 cm soil nitrate-N(NO;-N) concentration. Urine N input changed soil physicochemical properties, nitrification, denitrification, and N leaching processes, and therefore affected the availability of N accumulation and consumption in soil. Under these conditions, the trade-off between soil NH;-N and NO;-N under the influence of yak and Tibetan sheep urine application would change the form and concentration of available N, thereby altering the plant N uptake and utilization strategy of alpine grassland. The conclusions of this study coul

关键词： Livestock urine Mineral nitrogen Nitrification Denitrification Qinghai-Tibetan Plateau

Effects of rock fragments on yak dung greenhouse gas emissions on the Qinghai-Tibetan Plateau

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Journal of Mountain Science 2016年第11期13卷 2006-2014页

作者： du zi-yin WANG Xiao-dan LIU Xiu-ping CAI Yan-jiang Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Center for Agricultural Resources Research Institute of Genetics and Developmental BiologyChinese Academy of SciencesShijiazhuang 050021China

dung deposition is an important pathway of nutrient return and redistribution in alpine grasslands of the Qinghai-Tibetan *** date,information on the greenhouse gas emissions of yak dung on alpine grasslands,especially where there are large amounts of rock fragments,is *** aim,therefore,was to evaluate variations in N_2O,CH_4,and CO_2 emissions from yak dung(CCD),and compare it to dung placed on rock fragments(RCD),alpine steppe soil(CSD),and a soil and rock fragment mixture(RSD) over a 30-day incubation *** results showed that the total N_2O emissions from treatments without soil were significantly(P dung pats elevated the globalwarming potential(GWP),while the addition of rock fragments to the soil significantly(P ducing emissions of the three greenhouse *** therefore suggest that interactions between rock fragments and alpine steppe soil are effective in decreasing yak dung greenhouse gas *** finding indicates that rock fragments are an effective medium for reducing greenhouse gas emissions from dung pats,and more attention should therefore be paid to evaluate its ecological impact in future *** results should help guide scientific assessments of regional GHG budgets in agricultural ecosystems where the addition of livestock manure to soils with large amounts of rock fragments is common.

关键词： Rock fragments Yak dung Nitrous oxide Methane Qinghai-Tibetan Plateau

Geometry and formation mechanism of tension gashes and their implication on the hydrocarbon accumulation in the deep-seated strata of sedimentary basin:A case from Shunnan area of Tarim Basin

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Petroleum Science 2024年第1期21卷 87-99页

作者： Yan-Nan du Kong-You Wu yin Liu Yan-ying Li zi-Cheng Cao You-Wei Cui Jun Liu Key Laboratory of Deep Oil and Gas School of GeosciencesChina University of Petroleum(East China)Qingdao 266580ShandongChina Exploration and Development Research Institute SINOPEC Northwest Oilfield BranchUrumqi 830011XinjiangChina The Fifth Gas Production Plant Changqing OilfieldPetroChinaXi'an 710018ShaanxiChina

With the theoretical and technological developments related to cratonic strike-slip faults,the Shuntuoguole Low Uplift in the Tarim Basin has attracted considerable attention *** by multi-stage tectonic movements,the strike-slip faults have controlled the distribution of hydrocarbon resources owing to the special fault characteristics and fault-related *** contrast,the kinematics and formation mechanism of strike-slip faults in buried sedimentary basins are difficult to investigate,limiting the discussion of these faults and hydrocarbon *** this study,we identified the characteristics of massive sigmoidal tension gashes(STGs)that formed in the Shunnan area of the Tarim ***-resolution three-dimensional seismic data and attribute analyses were used to investigate their geometric and kinematic ***,the stress state of each point of the STGs was calculated using seismic curvature ***,the formation mechanism of the STGs and their roles in controlling hydrocarbon migration and accumulation were *** results suggest that:(1)the STGs developed in the Shunnan area have a wide distribution,with a tensile fault arranged in an enéchelon pattern,showing an S-shaped *** STGs formed in multiple stages,and differential rotation occurred along the direction of strike-slip stress during formation.(2)Near the principal displacement zone of the strike-slip faults,the stress value of the STGs was higher,gradually decreasing at both *** shallow layer deformation was greater than the deep layer deformation.(3)STGs are critical for connecting source rocks,migrating oil and gas,sealing horizontally,and developing efficient *** study not only provides seismic evidence for the formation and evolution of super large STGs,but also provides certain guidance for oil and gas exploration in this area.

关键词： Tarim Basin Sigmoidal tension gashes Seismic attributes Shear stress calculation Formation mechanism Reservoir control

A Method of Generating Semi-Experimental Biomedical Datasets

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Journal of Beijing Institute of Technology 2024年第3期33卷 219-226页

作者： Jing Wang Naike du zi He Xiuzhu Ye School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China

This paper proposed a method to generate semi-experimental biomedical datasets based on full-wave simulation *** system noise such as antenna port couplings is fully considered in the proposed datasets,which is more realistic than synthetical *** this paper,datasets containing different shapes are constructed based on the relative permittivities of human ***,a back-propagation scheme is used to obtain the rough reconstructions,which will be fed into a U-net convolutional neural network(CNN)to recover the high-resolution *** results show that the network trained on the datasets generated by the proposed method can obtain satisfying reconstruction results and is promising to be applied in real-time biomedical imaging.

关键词： electromagnetic imaging dataset biomedical imaging

Mechanical behavior of nanorubber reinforced epoxy over a wide strain rate loading

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Nano Materials Science 2024年第1期6卷 106-114页

作者： yinggang Miao Jianping yin Wenxuan du Lianyang Chen Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications School of AeronauticsNorthwestern Polytechnical UniversityXi'anShaanxi710072China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong UniversityXi'anShaanxi710049China Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application School of AeronauticsNorthwestern Polytechnical UniversityXi'anShaanxi710072China

Nanorubber/epoxy composites containing 0,2,6 and 10 wt%nanorubber are subjected to uniaxial compression over a wide range of strain rate from 8×10^(-4) s^(-1) to~2×10^(4) s^(-1).Unexpectedly,their strain rate sensitivity and strain hardening index increase with increasing nanorubber *** mechanisms are proposed based on numerical simulations using a unit cell *** increase in the strain rate sensitivity with increasing nanorubber content results from the fact that the nanorubber becomes less incompressible at high strain,generating a higher hydro-static *** shear localization starts to occur in the epoxy under a strain rate of 22,000 s^(-1) when the strain exceeds *** presence of nanorubber in the epoxy reduces adiabatic shear localization by preventing it from propagating.

关键词： Strain rate Strain hardening Nano rubber Epoxy Adiabatic shearing localization

A general descriptor for guiding the electrolysis of CO_(2)in molten carbonate

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Green Energy & Environment 2024年第4期9卷 748-757页

作者： Zhengshan Yang Bowen Deng Kaifa du Huayi yin Dihua Wang School of Resource and Environmental Sciences Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and EnergyWuhan UniversityWuhan430072China

Molten carbonate is an excellent electrolyte for the electrochemical reduction of CO_(2)to carbonaceous ***,the electrolyte–electrode-reaction relationship has not been well ***,we propose a general descriptor,the CO_(2)activity,to reveal the electrolyte–electrode-reaction relationship by thermodynamic calculations and experimental *** studies agree well with theoretical predictions that both cations(Li^(+),Ca^(2+),Sr^(2+)and Ba^(2+))and anions(BO_(2)^(-),Ti_(5)O_(14)^(8-),SiO_(3)^(2-))can modulate the CO_(2)activity to control both cathode and anode reactions in a typical molten carbonate electrolyzer in terms of tuning reaction products and *** this regard,the reduction of CO_(3)^(2-)can be interpreted as the direct reduction of CO_(2)generated from the dissociated CO_(3)^(2-),and the CO_(2)activity can be used as a general descriptor to predict the electrode reaction in molten ***,the CO_(2)activity descriptor unlocks the electrolyte–electrode-reaction relationship,thereby providing fundamental insights into guiding molten carbonate CO_(2)electrolysis.

关键词： Molten carbonate CO_(2)activity CO_(2)RR Electrolyte engineering Carbon

Tuning heterogeneous microstructures to enhance mechanical properties of nano-TiN particle reinforced Haynes 230 composites by laser powder bed fusion

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Rare Metals 2024年第9期43卷 4548-4565页

作者： Wen-Jie Liu Hui Li Qian-Xing yin He-Jun du School of Power and Mechanical Engineering Wuhan University The Institute of Technological Sciences Wuhan University School of Mechanical&Aerospace Engineering Nanyang Technological University

Laser powder bed fusion(LPBF) is considered to be one of the most promising additive manufacturing technologies for producing components with geometries and high geometrical precision that are unattainable by traditional technologies. The superalloy exhibits exceptional mechanical and high-temperature performances,rendering it a prime candidate for advanced aero-engine applications. Despite the high demand for LPBF-manufactured superalloys, the superalloy is one of the materials manufactured difficultly by LPBF due to their large laser absorptivity fluctuation, poor molten pool stability and sharp temperature gradient. Hence, superalloys are characterized by severe pores, undesirable coarse columnar grains and poor mechanical properties. In this work, the effect of nano-Ti N particles on defects, molten pool characteristics and microstructure and performance of the composites were investigated. The 4.5 wt% Ti N/Haynes230 samples exhibited exceptional nanohardness and elastic modulus with maximum values reaching 5.53 GPa and 240.03 GPa, respectively. These superior mechanical properties were attributed to the combined effects of spatter and gas pore inhibition, grain refinement and duplex nanophases strengthening. Moreover, the stability of molten pool was enhanced, and spatter was effectively suppressed by adding nano-Ti N particles, while grain refinement and columnar to equiaxed transitions were promoted. Furthermore, the matrix exhibited a high dislocation density due to a significant hindrance of dislocation movement caused by massive nano-phases(e.g., Ti N and M23C6), resulting in the formation of extensive dislocation tangles and *** work offers novel insights into the role of nanoparticles reinforced superalloy composites by LPBF.

关键词： Composites Laser powder bed fusion Mechanical properties Microstructure Molten pool characteristics

Forecast of cosmological constraints with superluminous supernovae from the Chinese Space Station Telescope

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Science China(Physics,Mechanics & Astronomy) 2024年第10期Mechanics & Astronomy) .卷 132-142页

作者： Xuan-Dong Jia Jian-Ping Hu Fa-yin Wang zi-Gao Dai School of Astronomy and Space Science Nanjing University Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) Ministry of Education Department of Astronomy University of Science and Technology of China

Superluminous supernovae（SLSNe） are a class of intense celestial events that can be standardized for measuring cosmological parameters, bridging the gap between type Ia supernovae and the cosmic microwave background. In this work, we discuss the cosmological applications of SLSNe from the Chinese Space Station Telescope（CSST）. Our estimation suggests that SLSNe rate is biased tracing the cosmic star formation rate, exhibiting a factor of （1 + z）1.2. We futher predict that CSST is poised to observe ～360 SLSNe in the 10 square degrees ultra-deep field survey within a span of 2.5 years. A stringent constraint on cosmological parameters can be derived from their peak-color relationship. CSST is anticipated to uncover a substantial number of SLSNe, contributing to a deeper understanding of their central engines and shedding light on the nature of dark energy at high redshifts.

关键词： supernovae cosmology cosmological constant

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