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Observation of specific ion effects in humus aggregation process

Pedosphere 2021年第5期31卷 736-745页

作者： Rui TIAN Xinmin LIU Xiaodan gao Rui LI Hang LI Chongqing Key Laboratory of Soil Multi-scale Interfacial Process College of Resources and EnvironmentSouthwest UniversityChongqing 400715(China)

Specific ion effects play a vital role in a variety of colloidal and interfacial ***,few studies have reported the specific ion effects in the humus aggregation process,which strongly influence the transport and fate of environmental *** this study,soil humus colloids were prepared and characterized,and the specific ion effects on humus aggregation in electrolyte solutions were investigated at a variety of concentrations and pH values using dynamic light scattering *** energy(ΔE),which is known to reflect the dynamics and stability of a colloidal system,was used to quantitatively characterize the specific ion *** results showed that given ΔE value of 2.48×10^(3) J mol^(-1) at pH 3.0,the electrolyte concentrations were 91.6,58.2,3.8,and 0.8 mmol L^(-1) for Na^(+),K^(+),Mg^(2+),and Ca_(2+),respectively,thus indicating significant specific ion effects in the humus aggregation *** importantly,decreasing the electrolyte concentrations increased the differences in the ΔE value between two cation species with the same valence(i.e.,ΔE_(Na)-ΔE_(K) and ΔE_(Mg)-ΔE_(Ca)),while increasing the pH increased the magnitude of ΔE_(Mg)-ΔE_(Ca).However,the classic Derjaguin,Landau,Verwey,and Overbeek(DLVO)theory and the double layer theory,as well as the currently widely used ionic hydration and dispersion effects,failed to predict the experimentally observed increase in the specific ion effects with decreasing electrolyte concentrations in a quantitative *** results have implications for the necessity of involving specific ion effects for a better understanding of humus aggregation and interactions in aqueous and soil systems.

关键词： Derjaguin Landau Verwey and Overbeek theory double layer theory ionic dispersion ionic hydration supramolecular aggregates

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Variations of suction and suction stress of unsaturated loess due to changes in lignin content and sample preparation method

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Journal of Mountain Science 2021年第8期18卷 2168-2183页

作者： LIU Wei WANG Qian LIN gao-chao XU Xiang-tian Institute of Transportation Inner Mongolia UniversityHohhot010070China Key Laboratory of Loess Earthquake Engineering China Earthquake Administration&Gansu Province Lanzhou730000China School of Civil and Environmental Engineering University of New South WalesSydneyNSW2052Australia

Unsaturated loess in natural sites loses stability as the overburden load continuously *** soil modifiers such as cement and fly ash affect the surrounding environment.A new type of material,i.e.,lignin,is environmentally friendly and able to increase the strength of ***,the engineering characteristics of the improved loess under unsaturated conditions are not yet *** this study,the soil-water characteristic curves(SWCCs)of lignin-improved loess samples were determined from 0 kPa to 700 kPa using a pressure plate instrument,and then,they were fitted using the van Genuchten(VG)model and the Fredlund and Xing(FX)*** addition,the effects of the lignin content and sample preparation methods on the SWCCs were investigated to determine the optimal lignin content and a suitable sample preparation method for loess *** the lignin content increases,the matric suction and residual water content of the improved loess *** suction stress increases with the increasing lignin contents of 1%–2%.At lignin contents of 3%–4%,the suction stress begins to decrease and the samples prepared using the slurry method has a lower suction stress than that prepared using the wet mixing *** air entry value(AEV)increases with increasing lignin *** addition,scanning electron microscopy(SEM)was used to investigate the microstructural *** was found that after the addition of lignin,the entrapment of the loess particles by the lignin fibers created some larger particles and smaller pore diameters,which in turn led to poor connectivity of the loess *** changes cause the matric suction of the modified loess to increase.

关键词： Loess treated with lignin Sampling method Soil-water characteristic curve(SWCC) Suction stress characteristic curve(SSCC) Scanning electron microscopy(SEM)

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X-ray flares raising upon magnetar plateau as an implication of a surrounding disk of newborn magnetized neutron star

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Research in Astronomy and Astrophysics 2021年第12期21卷 326-336页

作者： Tian-Ci Zheng Long Li Le Zou Xiang-gao Wang Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China

The X-ray flares have usually been ascribed to long-lasting activities of the central engine of gamma-ray bursts(GRBs),e.g.,fallback *** GRB X-ray plateaus,however,favor a millisecond magnetar central *** fallback accretion can be significantly suppressed due to the propeller effect of a ***,if the propeller regime cannot resist the mass flow onto the surface of the magnetar efficiently,the X-ray flares raising upon the magnetar plateau would be *** this work,such peculiar cases are connected to the accretion process of the magnetars,and an implication for magnetar-disc structure is *** investigate the repeated accretion process with multi-flare GRB 050730,and give a discussion for the accretion-induced variation of the magnetic field in GRB 111209 *** or more flares exhibit in the GRB 050730,060607 A and 140304 A;by adopting magnetar mass M=1.4 M_(⊙)and radius R=12 km,the average mass flow rates of the corresponding surrounding disk are 3.53×10^(-4)M_(⊙)s^(-1).4.23×10^(-4)M_(⊙)s^(-1),and 4.33×10^(-4)M_(⊙)s^(-1),and the corresponding average sizes of the magnetosphere are 5.01×10^(6)cm,6.45 x 10^(-6)cm,and 1.09×10^(-7)cm,respectively.A statistic analysis that contains eight GRBs within 12 flares shows that the total mass loading in single flare is~2×10^(-5)M_(⊙).In the lost mass of a disk,there are about 0.1%used to feed a collimated jet.

关键词： accretion accretion disk stars:magnetars gamma-ray burst:individual(GRB 050730,GRB 111209A)

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Uncovering the coupling effect with energy-related carbon emissions and human development variety in Chinese provinces

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Journal of Environmental Sciences 2024年第5期139卷 527-542页

作者： Liu Chen Yiqi Tan Gengpei Lv Weiguang Cai Xiaofeng gao Rui Li School of Management Science and Real Estate Chongqing UniversityChongqing 400044China State Key Joint Laboratory of Environment Simulation and Pollution Control(SKLESPC) School of EnvironmentTsinghua UniversityBeijing 100084China Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment Ministry of EducationCollege of Environment and EcologyChongqing UniversityChongqing 400044China

Lessening energy-related carbon emissions has become a crucial measure to achieve Chinese carbon *** study is the first to construct a Difference in Carbon pressures-adjusted Human Development Index(DCHDI)model for the purpose of exploring the coupling effect between carbon emissions and human development variety from 2000 to 2019 in Chinese *** demonstrate the following.(1)The total energy-related carbon footprint of 30 provinces in China reached 10.2 billion tons in 2019,with an average annual growth rate of 6.93% over the past two decades;and the provinces with the highest carbon emissions per capita are InnerMongolia,Ningxia,and Shanxi.(2)At the provincial level,we observed that the Human Development Index(HDI),which includes life expectancy,education,and income,has been rising,while Beijing,Shanghai,and Tianjin entered the super-high HDI level before 2008.(3)The entire coupling effect of 30 Chinese provinces has been broadly fortified in the last 20 years,but the growth rate of DCHDI values in 2011-2019 has slowed down compared with that in 2000-2010;the clustering phenomenon demonstrated that this discovery is associated with historical peaks in total carbon emissions.(4)The co-ordination degree of carbon emissions per capita and HDI was verified,and 96% of the data points were found in the range of super high coupling coordination ***,this study provides the government with worthwhile guidance for decision-making and carbon reduction strategies for other countries struggling to advance human sustainable development.

关键词： Energy-related carbon emissions Human sustainable development DCHDI model Coupling effect Chinese provinces

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Spatial-temporal Analysis and Prediction of Precipitation Extremes: A Case Study in the Weihe River Basin, China

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Chinese Geographical Science 2022年第2期32卷 358-372页

作者： QIU Dexun WU Changxue MU Xingmin ZHAO Guangju gao Peng State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences and Ministry of Water ResourcesYangling 712100China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest Agriculture and Forestry UniversityYangling 712100China

Extreme precipitation events bring considerable risks to the natural ecosystem and human *** the spatial-temporal characteristics of extreme precipitation and predicting it quantitatively are critical for the flood prevention and water resources planning and *** this study,daily precipitation data(1957–2019)were collected from 24 meteorological stations in the Weihe River Basin(WRB),Northwest China and its surrounding *** first analyzed the spatial-temporal change of precipitation extremes in the WRB based on space-time cube(STC),and then predicted precipitation extremes using long short-term memory(LSTM)network,auto-regressive integrated moving average(ARIMA),and hybrid ensemble empirical mode decomposition(EEMD)-LSTM-ARIMA *** precipitation extremes increased as the spatial variation from northwest to southeast of the *** were two clusters for each extreme precipitation index,which were distributed in the northwestern and southeastern or northern and southern of the *** precipitation extremes in the WRB present a strong clustering ***,the pattern of only high-high cluster and only low-low cluster were primarily located in lower reaches and upper reaches of the WRB,*** spots(25.00%–50.00%)were more than cold spots(4.17%–25.00%)in the *** spots were mainly concentrated in the northwestern part,while hot spots were mostly located in the eastern and southern *** different extreme precipitation indices,the performances of the different models were *** accuracy ranking was EEMD-LSTM-ARIMA>LSTM>ARIMA in predicting simple daily intensity index(SDII)and consecutive wet days(CWD),while the accuracy ranking was LSTM>EEMD-LSTM-ARIMA>ARIMA in predicting very wet days(R95 P).The hybrid EEMD-LSTM-ARIMA model proposed was generally superior to single models in the prediction of precipitation extremes.

关键词： precipitation extremes space-time cube(STC) ensemble empirical mode decomposition(EEMD) long short-term memory(LSTM) auto-regressive integrated moving average(ARIMA) Weihe River Basin,China

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Magnetic characteristics of lake sediments in Qiangyong Co Lake,southern Tibetan Plateau and their application to the evaluation of mercury deposition

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Journal of Geographical Sciences 2020年第9期30卷 1481-1494页

作者： gao Xing KANG Shichang LIU Qingsong CHEN Pengfei DUAN Zongqi State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesCASLanzhou 730000China Departme nt of Ocea n Scie nee and Engin eeri ng Souther n Un iversity of Science and Tech no logyShe nzhen 518055GuangdongChina The Geographical Society of China Beijing 100101China

Heavy metals,one of the most toxic classes of pollutants,are resistant to degradation and harmful to the biological *** lakes that have developed on the Tibetan Plateau are ideal regions to investigate historic heavy metal pollution,particularly through the use of the reliable 210 Pb dating *** magnetism has been successfully applied to estimate heavy metal pollution in different environmental systems due to its characteristics of simple processing steps,good sensitivity,and ***,it has not yet been applied to assess heavy metal pollution in lake sediments on the Tibetan Plateau.A series of environmental magnetic investigations of Qiangyong Co Lake sediments(southern Tibetan Plateau) was therefore conducted to explore the relationship between magnetic minerals and mercury(Hg) *** results showed that the magnetic mineral species in lake sediments remained stable,with similar levels of four different components from 1899 to ***,the proportion of component 1(C1,hematite) increased continuously with the corresponding decrease in the proportion of C2(goethite),while the proportions of C3 and C4(magnetite) did not change *** a result,the bulk magnetic signals(e.g.,SIRM and clf) were unsuitable for the evaluation of the Hg concentration;however,the proportion of hematite had a strong positive correlation with the Hg *** is possible that the Qiangyong Glacier(the main water supply for Qiangyong Co Lake) has experienced faster melting with global and local warming,and the Hg trapped in cryoconite and ice was ***,with a large specific surface area,has a strong capacity for absorbing Hg,and both materials are ultimately transported to Qiangyong Co *** proportion of hematite in a sample is therefore a suitable semi-quantitative proxy that can be used to evaluate the Hg concentration in Qiangyong Co Lake *** study confirmed that the variation of

关键词： southern Tibetan Plateau Qiangyong Co Lake environmental magnetism mercury(Hg)deposition

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Effect of inorganic salt on the thermal degradation of nitrocellulose and reaction mechanism of its mixture

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Defence Technology（防务技术） 2023年第9期27卷 111-118页

作者： Guo-zhong Xu Xu gao Mi Li Zhong-xuan Han Lin Jiang School of Mechanical Engineering Nanjing University of Science and TechnologyChina

In this study,to better understand the reaction mechanism between inorganic salts and nitrocellulose,CaCO_(3) and Li_(2)CO_(3) were evaluated with respect to their effects on the thermal degradation of NC in nitrogen atmosphere using TG/DSC at three different heating rates(2,5,10 K/min).The numerical relationship between activation energy(E)and conversion rate was obtained by FWO and KAS method,and it was discovered that CaCO_(3) could improve the thermal stability of *** energy values were calculated by Kissinger method,and it was found that NC that contain Li2CO3had the highest activation energy while NC containing CaCO3had the lowest E *** combining the thermal analysis data with Malek method,the most probable mechanism model of thermal degradation is obtained as Sesták-Berggren model,which expression is f(α)=α^(m)(1-α)^(n).As a result of this study,there are certain guiding principles that can be applied to the pyrolysis reaction model and to the actual production process of nitrocellulose.

关键词： Thermal analysis Thermal decomposition mechanism Malek method Nitrocellulose Inorganic salt

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Predictive cruise control for heavy trucks based on slope information under cloud control system

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Journal of Systems Engineering and Electronics 2022年第4期33卷 812-826页

作者： LI Shuyan WAN Keke gao Bolin LI Rui WANG Yue LI Keqiang College of Engineering China Agricultural UniversityBeijing 100083China School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China

With the advantage of fast calculation and map resources on cloud control system(CCS), cloud-based predictive cruise control(CPCC) for heavy trucks has great potential to improve energy efficiency, which is significant to achieve the goal of national carbon neutrality. However, most investigations focus on the on-board predictive cruise control(PCC) system,lack of research on CPCC architecture under CCS. Besides, the current PCC algorithms have the problems of a single control target and high computational complexity, which hinders the improvement of the control effect. In this paper, a layered architecture based on CCS is proposed to effectively address the realtime computing of CPCC system and the deployment of its algorithm on vehicle-cloud. In addition, based on the dynamic programming principle and the proposed road point segmentation method(RPSM), a PCC algorithm is designed to optimize the speed and gear of heavy trucks with slope information. Simulation results show that the CPCC system can adaptively control vehicle driving through the slope prediction, with fuel-saving rate of 6.17% in comparison with the constant cruise control. Also,compared with other similar algorithms, the PCC algorithm can make the engine operate more in the efficient zone by cooperatively optimizing the gear and speed. Moreover, the RPSM algorithm can reconfigure the road in advance, with a 91% roadpoint reduction rate, significantly reducing algorithm ***, this study has essential research significance for the economic driving of heavy trucks and the promotion of the CPCC system.

关键词： predictive cruise control(PCC) cloud control system(CCS) layered architecture road point segmentation method(RPSM) economic driving

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Simulation and analysis of asteroid force closure anchoring performance based on discrete element method

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Chinese Journal of Aeronautics 2023年第8期36卷 381-394页

作者： Tingzhang WANG Qiquan QUAN Hongshuai gao Mengxue LI Dewei TANG Zongquan DENG State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

Asteroid exploration is significant for studying the origin of the solar system,establishing planetary defenses,and alleviating the resource crisis of the *** anchoring is the basis of in-situ exploration and resource development and ***,the performance of asteroid force-closure anchoring is investigated using the discrete element *** micro parameters of the simulated materials are calibrated with angle of repose and uniaxial compression experiments,based on which the regional modeling method is adopted to establish the anchoring discrete element *** anchoring experiments are conducted on a self-developed microgravity simulation platform to verify the accuracy of the simulation *** asteroid anchoring simulations are performed to investigate the influence of external force on the anchoring *** analysis of anchoring force varying with time and the interaction between the anchor and regolith particles reveals the influence mechanism of external force direction on the anchoring *** external force direction affects the critical anchoring force by influencing the failure of the force-closure *** comprehensive analysis of simulation results clarifies the variation of the critical anchoring force with the external ***,a stable anchoring region is established,beneficial for asteroid anchoring device design.

关键词： Anchoringforce Asteroid exploration Discrete element method Force closureanchoring Simulationverification

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Three-dimensional dynamic sea surface modeling based on ocean wave spectrum

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Acta Oceanologica Sinica 2021年第10期40卷 38-48页

作者： Zhimiao Chang Fuxing Han Zhangqing Sun Zhenghui gao Lili Wang College of Geoexploration Science and Technology Jilin UniversityChangchun 130026China Geophysical Exploration and Research Institute of Jilin Oilfield Songyuan 138006China

In conventional marine seismic exploration data processing,the sea surface is usually treated as a horizontal free ***,the sea surface is affected by wind and waves and there often exists dynamic small-range *** dynamic fluctuations will change the energy propagation path and affect the final imaging *** theoretical research,different sea surface conditions need to be described,so it is necessary to study the modeling method of dynamic undulating sea *** from the commonly used sea surface mathematical simulation methods,this paper mainly studies the realization process of simple harmonic wave and Gerstner wave sea surface simulation methods based on ocean wave spectrum,and compares their advantages and *** at the shortcomings of the simple harmonic method and Gerstner method in calculational speed and sea surface simulation effect,a method based on wave equation and using dynamic boundary conditions for sea surface simulation is *** calculational speed of this method is much faster than the commonly used simple harmonic method and Gerstner wave *** addition,this paper also compares the new method with the more commonly used higher-order spectral methods to show the characteristics of the improved wave equation method.

关键词： sea surface simulation simple harmonic Gerstner wave wave equation ocean wave spectrum high-order spectral method

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