检索结果-南通市图书馆

Influence of vegetation type and topographic position on volumetric soil water content dynamics and similarity among surface and deep soil layers

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

International Soil and Water Conservation Research 2023年第1期11卷 183-196页

作者： Muxing Liu Qiuyue Wang Jun Yi Hailin Zhang Ji Liu Wei Hu key laboratory for geographical process analysis&simulation Hubei ProvinceWuhan430079China College of urban and environmental sciences Central China Normal UniversityWuhan430079China The New Zealand Institute for Plant and Food Research Limited Private Bag 4704Christchurch8140New Zealand

Clarifying the mechanisms governing volumetric soil water content(VSWC)dynamics in soil profiles is essential,as it can help to elucidate soil water transport processes and improve the prediction accuracy of soil hydrological processes.Using Spearman's rank correlation and wavelet coherence analysis methods,similarity in soil profile VSWC dynamics and factors governing VSWC soil profile dynamics in upslopes and downslopes under three vegetation types(evergreen forest[EG],secondary deciduous forest mixed with shrubs[SDFS],and deforested pasture[DP])at different time scales(hourly,daily,weekly,and monthly)and in different seasons were analyzed.The results revealed significant similarity in the VSWC of different soil depths(Pweekly(42.8%)>daily(21.8%).The effects of soil properties(e.g.,texture,saturated hydraulic conductivity),rainfall,and potential evapotranspiration(ET_(p))on VSWC similarity were related to the time scale and season in which VSWC monitoring took place.Soil properties had apparent effects on VSWC similarity at longer time scales(i.e.,monthly),with a high SCA.In contrast,the effects of rainfall and ET_(p) on VSWC similarity were concentrated at weekly and daily scales,with a relatively low SCA.Rainfall and ET_(p) dominated VSWC dynamics in the summer and fall,respectively.These results imply the use of measured VSWC at one soil depth to predict the VSWC at other soil depths was a reliable method.While the in-fluence of time scale effects and seasonal variations on prediction accuracy of VSWC should be considered.

关键词： Volumetric soil water content Wavelet analysis Significant coherence area Time scale Vegetation type Slope postion

Sensitivity analysis of modeling parameters to soot and PAHs prediction in ethylene inverse diffusion flame

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological sciences) 2024年第2期67卷 486-498页

作者： WU BingKun LI TianJiao LIU Dong MIIT key laboratory of Thermal Control of Electronic Equipment School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China Advanced Combustion laboratory School of Energy and Power EngineeringNanjing University of Science and Technology Nanjing 210094China

The soot formation model based on inverse ethylene diffusion flames was performed to study the sensitivity of the soot formation process to the prediction results.The effects of efficiency parameters such as soot inception,surface growth and coagulation on the simulation results were studied by using the adjustable efficiency model.In addition,the reversible soot model and conjugate heat transfer(CHT)model were also introduced to explore their advantages.Results indicated that,among adjustable efficiency parameters,the nucleation efficiency had the greatest influence on the predicted soot and PAHs distributions,while the Habstraction-C2H2-addition(HACA)process and PAH adsorption surface growth efficiencies impacted little.The adjustable efficiency parameters had a significant effect on the concentration of soot gaseous precursors and soot particles,but their effects on temperature,gas phase molecules,and intermediate species were not obvious.When the nucleation efficiency increased from 2×10^(-6)to 1×10^(-4),the predicted value of the integrated soot was increased by nearly 50%,and the maximum primary particle number density and the number of aggregates were increased by an order of magnitude.The maximum concentration of BAPYR was doubled.However,the peak temperature along the axial direction increased by only 3.5 K.Using the reversible soot model,the approximation results of the adjustable efficiency parameters could be modified,which showed the feasibility of the model.The use of the CHT model promoted pyrolysis of the fuel below the outlet of the fuel tube,with high-temperature zones,soot zones,and PAHs zones moving towards higher flame heights.Besides,when using the reversible model and the CHT model,the maximum soot volume fraction decreased by 39%compared with the basic efficiency parameters,while the concentration of BAPYR increased by 162%,and the concentrations of gas phase species were decreased.

关键词： inverse diffusion flames soot formation soot model ethylene

Inverse Calculation and Regularization process for the Solar Aspect System(SAS) of HXI Payload on ASO-S Spacecraft

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第4期24卷 13-34页

作者： Ji-Rui Yu Ping Ruan Yang Su Ying-Hong He Jin-You Tao Zhe Zhang Song Guo Bin Xue Jian-Feng Yang Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of sciences Xi'an 710119China University of Chinese Academy of sciences Beijing 100049China key laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 20034China school ofAstronomy and Space Science Universityof Science and Technology of ChinaHefei 230026China

For the ASO-S/HXI payload, the accuracy of the flare reconstruction is reliant on important factors such as the alignment of the dual grating and the precise measurement of observation orientation. To guarantee optimal functionality of the instrument throughout its life cycle, the Solar Aspect System (SAS) is imperative to ensure that measurements are accurate and reliable. This is achieved by capturing the target motion and utilizing a physical model-based inversion algorithm. However, the SAS optical system’s inversion model is a typical ill-posed inverse problem due to its optical parameters, which results in small target sampling errors triggering unacceptable shifts in the solution. To enhance inversion accuracy and make it more robust against observation errors, we suggest dividing the inversion operation into two stages based on the SAS spot motion model. First, the as-rigid-aspossible (ARAP) transformation algorithm calculates the relative rotations and an intermediate variable between the substrates. Second, we solve an inversion linear equation for the relative translation of the substrates, the offset of the optical axes, and the observation orientation. To address the ill-posed challenge, the Tikhonov method grounded on the discrepancy criterion and the maximum a posteriori (MAP) method founded on the Bayesian framework are utilized. The simulation results exhibit that the ARAP method achieves a solution with a rotational error of roughly±3 5 (1/2-quantile);both regularization techniques are successful in enhancing the stability of the solution, the variance of error in the MAP method is even smaller—it achieves a translational error of approximately±18μm (1/2-quantile) in comparison to the Tikhonov method’s error of around±24μm (1/2-quantile). Furthermore, the SAS practical application data indicates the method’s usability in this study. Lastly, this paper discusses the intrinsic interconnections between the regularization methods.

关键词： methods:data analysis Sun:flares Sun:X-rays gamma rays

Climatic Fluctuation of Marine Isotope Stage 9: A Case Study in the Southern Margin of the Chinese Loess Plateau

在线全文

学校读者我要写书评

暂无评论

地球科学学刊:英文版 2023年第5期34卷 1556-1566页

作者： Tieniu Wu Antai Cheng Henry Lin Hailin Zhang Yi Jie key laboratory for geographical process analysis&simulation Hubei ProvinceCentral China Normal UniversityWuhan 430079China Department of Ecosystem Science and Management The Pennsylvania State UniversityUniversity ParkPA 16802U.S.A. College of urban and environmental sciences Central China Normal UniversityWuhan 430079China

Marine Isotope Stages(MIS) 9 has been proposed as an analog for the present warm period. However, detailed studies of this geological time period are rare in loess-paleosol sequence. In the Chinese Loess Plateau(CLP), the corresponding stratum is the third paleosol layer(S3). Here, we report the terrestrial reconstruction of climatic fluctuations during MIS 9 by analyzing the paleo-climate indexes of S3 with high sampling density. Our results showed that:(1) During the period of MIS 9, the main climatic sub-cycle was 29 ka;(2) MIS 9 could be divided into five sections, MIS 9a, 9b, 9c, 9d, and 9e. Among them, MIS 9a, 9c, and 9e were warm stages, while MIS 9b and 9d were cool intervals;and 3) There were also three swift warm-wet events and one cool-dry event, which occurred around 332 –331, 324–323, 311–310, and 331–329 ka BP, respectively. The overall trend of paleo-climate fluctuation correlated approximately with SPECMAP, LR04 stack and Iberian margin deep-sea cores. This study suggested that the paleosol records in the southern margin of the CLP have global significance and contain more detailed climatic signals than marine deposits.

关键词： MIS 9 climatic fluctuation Paleosol S3 Chinese Loess Plateau environmental geology

Continuous-flow enzymatic synthesis of chiral lactones in a three-dimensional microfluidic reactor

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第3期35卷 299-303页

作者： Xuelei Deng Meng Fan Miao Wu Xiaoyan Zhang Ya Cheng Jianye Xia Yingping Zhuang Weiping Zhu Xuhong Qian Yunpeng Bai State key laboratory of Bioreactor Engineering Shanghai Collaborative Innovation Center for BiomanufacturingEast China University of Science and TechnologyShanghai 200237China The Extreme Optoelectromechanics laboratory School of Physics and Materials ScienceEast China Normal UniversityShanghai 200241China Tianjin Institute of Industrial Biotechnology Chinese Academy of SciencesTianjin 300308China

A new continuous-flow process for the enzymatic synthesis of optically pureγ-lactones,which are used as flavors and fragrances in the food and cosmetic industries,was developed in a three-dimensional microfluidic reactor.The microchannels(175 mm in length,0.9 mm in depth,and 1.72 mL in volume)were carved precisely inside a single borosilicate glass(90 mm×75 mm×12 mm)with ultrafast femtosecond laser micromachining.The flow field analysis and reaction simulation showed that the mixing of substrates and enzymes was enhanced,allowing the adjustment of residence time in a wide window.SmCR_(V4),a carbonyl reductase with excellent catalytic activity and enantioselectivity towardγ/δ-keto acids,was employed for the asymmetric synthesis of various chiral lactones.30 mmol/L(R)-γ-decalactone(3g)can be obtained in 26 s with a space-time yield(STY)up to 16,877 g L^(-1)d^(-1),which is 14.4 times higher than the highest STY of batch reaction reported previously.This continuous-flow process was applied to the synthesis of 6 chiral lactones.In addition,the scaled-up synthesis of 3g was carried out in 6 cascade microreactors continuously for 6 h,demonstrating the feasibility and stability of the 3D continuous-flow process in enzymatic synthesis of optically pure compounds.

关键词： Continuous-flow Flow chemistry Microreactor Biocatalysis Carbonyl reductase Asymmetric reduction

Adaptive Integrated Coastal Zone Planning:History,Challenges,Advances,and Perspectives

在线全文

学校读者我要写书评

暂无评论

Chinese geographical Science 2024年第4期34卷 599-617页

作者： WANG Xinyi SU Fenzhen WANG Xuege PAN Tingting CUI Yikun LYNE Vincent YAN Fengqin State key laboratory of Resources and environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of ScienceBeijing 100049China school of Geography and Ocean sciences Nanjing UniversityNanjing 210023China Institute for Marine and Antarctic Studies University of TasmaniaTasmania 7004Australia

Coastal zones are dynamic,rich environments,now densely populated,and increasingly challenged by human and climatechange pressures.Effective long-term integrated coastal zone planning is needed to ensure sustainable environmental protection and economic development.In this study,we reviewed the history of coastal zone planning since its birth in the 1950s based on the literature retrieved from the Web of Science(Core Collection)from 2000–2023,then summarized the tools and spatial allocation methods commonly used in the planning process,and finally proposed potential solutions to the challenges faced.The results show that after decades of development,coastal zone planning has changed from a decentralized activity to a targeted and integrated one,with an increasing emphasis on the ecosystem approach and the use of multiple planning tools.Spatial analysis techniques and environmental modelling software have become increasingly popular.Linear programming and overlay analysis are common approaches when performing spatial optimization,but land-sea interactions and planning in the marine parts still lack in-depth analysis and practical experience.We are also aware that the challenges posed by the integration of administrative hierarchies,scoping and conservation objectives,stakeholder participation,consideration of social dimensions,and climate change are pervasive throughout the planning process.There is an urgent need to develop more flexible and accurate spatial modelling tools,as well as more efficient participatory methods,and to focus on the holistic nature of the land-sea system to create more resilient and sustainable coastal zones.

关键词： Integrated Coastal Zone Management(ICZM) coastal zone planning spatial optimization ecosystem-based management

维普期刊数据库博看期刊

Influences of rock fragments on the hydraulics and erosion of concentrated runoff in steep spoil heaps on the Loess Plateau of China

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2022年第5期37卷 553-562页

作者： Wenzhao Guo Hongliang Kang Xiao Yu Wenlong Wang Pei Tian State key laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Water and Soil Conservation Northwest Agriculture & Forestry University key laboratory for geographical process analysis & simulation of hubei province Central China Normal University

The soil-rock mixed spoil heaps are prone to severe soil erosion during heavy rain, causing severe land degradation and ecological and environmental damage. Nevertheless, past research on the erosion on spoil heaps has focused on soil particles that were readily eroded and disregarded the rock fragments(RF) that were not readily eroded. To explore the effect of the RF embedded in spoil heaps on the hydraulics of and erosion caused by concentrated runoff, scour-erosion experiments were implemented on three types of spoil heaps: RF = 7%, RF = 45%, and RF = 69%. The RF clearly reduced runoff and erosion on steep spoil heaps. As the RF increased from 7% to 69%, the runoff intensity and runoff coefficient decreased by 72.9%-79.1% and 83.2%-84.1% respectively, and the sediment concentration, soil denudation rate, and total soil loss decreased by 36.0%-47.8%, 83.7%-87.1%, and 87.0%-92.3%, respectively.Narrow rills were generated during the experiments, and the RF distinctly influenced the rill characteristics. High contents of RF restrained rill retreating and undercutting, and promoted rill widening. With an increase in RF, the flow shear stress and stream power gradually decreased, and the Darcy-Weisbach roughness coefficient increased. These findings imply that the RF dissipated the flow energy and reduced soil detachment capacity and sediment transport capacity. Soil detachment is strongly related to the Darcy-Weisbach roughness coefficient, Reynolds number, and runoff intensity,which may be the preferred descriptors of soil detachment. The current findings indicate that embedded rock fragments could effectively reduce soil loss on steep spoil heaps.

关键词： Soil erosion Runoff Rock fragments (RF) Rills Chinese loess plateau

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

模拟城际人口流动的量子谐振子模型

Journal of geographical sciences 2024年第3期34卷 459-482页

作者：胡旭钱凌欣钮潇雨高鸣罗文袁林旺俞肇元 school of Geography Nanjing Normal UniversityNanjing210023China key laboratory of Virtual Geographic Environment Nanjing Normal UniversityMinistry of EducationNanjing210023China Jiangsu Center for Collaborative Innovation in geographical Information Resource Development and Application Nanjing210023China

The simulation of intercity population mobility helps to deepen the understanding of intercity population mobility and its underlying laws,which has great importance for epidemic prevention and control,social management,and even urban planning.There are many factors that affect intercity population mobility,such as socioeconomic attributes,geographical distance,and industrial structure.The complexity of the coupling among these factors makes it difficult to simulate intercity population mobility.To address this issue,we propose a novel method named the quantum harmonic oscillator model for simulation of intercity population mobility(QHO-IPM).QHO-IPM describes the intercity population mobility as being affected by coupled driving factors that work as a multioscillator-coupled quantum harmonic oscillator system,which is further transformed by the oscillation process of an oscillator,namely,the breaking point of intercity population mobility.The intercity population mobility among seven cities in the Beijing-Tianjin-Hebei region and its surrounding region is taken as an example for verifying the QHO-IPM.The experimental results show that(1)compared with the reference methods(the autoregressive integrated moving average(ARIMA)and long and short-term memory(LSTM)models),the QHO-IPM achieves better simulation performance regarding intercity population mobility in terms of both overall trend and mutation.(2)The simulation error in the QHO-IPM for different-level intercity population mobility is small and stable,which illustrates the weak sensitivity of the QHO-IPM to intercity population mobility under different structures.(3)The discussion regarding the influence degree of different driving factors reveals the significant“one dominant and multiple auxiliary”factor pattern of driving factors on intercity population mobility in the study area.The proposed method has the potential to provide valuable support for understanding intercity population mobility laws and related decision-making on intercity population mobility c

关键词： intercity population mobility coupling driving factors quantum harmonic oscillator model probability distribution pattern optimization strategy

Utilization effect of water-land resources under the evolution of Chinese dietary patterns

在线全文

学校读者我要写书评

暂无评论

Journal of geographical sciences 2023年第4期33卷 741-759页

作者： ZHU Yuanyuan WANG Ziwei ZHU Xiaohua key laboratory of Geographic process analysis&simulation hubei province Central China Normal UniversityWuhan 430079China Institute of Geographic sciences and Natural Resources Research CASBeijing 100101China

Exploring the utilization effect of water-land resources under the evolution of dietary patterns is of great significance in achieving sustainable global food consumption and the effective allocation of national resources.Our selected study area was China,a country with rapidly changing dietary consumption patterns,and the research period was between 1987 and 2020.Based on the material called Chinese Dietary Guidelines 2021,this study introduced the“virtual water”and the“virtual land”to quantify the utilization effect of water-land resources under the evolution of Chinese dietary patterns.Results showed that the dietary patterns gradually changed from“cereal-vegetable-based consumption”to“diversified consumption”.Food consumption’s total water footprint(WF)increased from 471.1 Gm3in 1987 to 848.8 Gm3in 2020,with a growth rate of 80.2%.Moreover,the total land requirement for food(LRF)increased from 88.8 Mha in 1987 to 129.9 Mha in 2020,with a growth rate of 46.3%.Furthermore,the meat consumption was the major contributor to the increase in total WF(104.0%)and LRF(102.1%).In contrast to the balanced diet pattern,there was no waste of water-land resources consumption for the food consumption of urban-rural residents in China between 1987 and 2020.However,the consumption of water resources would gradually approach the resource cost under the balanced diet patterns.It would eventually break through the critical value and reach the state of resource waste.In addition,the findings showed that urban residents’waste rate of water-land resources for meat consumption increased by 142.3%compared with that in 1987.The research results can provide scientific guidance for resolving the food crisis under the supply of water-land resources in China and have an essential reference for national food security and sustainable development of resources and environment.

关键词： dietary patterns water-land resource utilization food security sustainable development China