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Temporal Variability in Soil CO_2 Emission in an Orchard Forest Ecosystem

Pedosphere 2008年第3期18卷 273-283页

作者： li yue-lin D. OTIENO K. OWEN ZHANG Yun J. TENHUNEN RAO Xing-Quan lin Yong-Biao South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 （China） Department of Plant Ecology University of Bayreuth 95440 Bayreuth （Germany） School of Resources and Environmental Science Hubei University Wuhan 430062 （China）

Temporal variability in soil CO2 emission from an orchard was measured using a dynamic open-chamber system for measuring soil CO2 effiux in Heshan Guangdong Province, in the lower subtropical area of China. Intensive measurements were conducted for a period of 12 months. Soil CO2 emissions were also modeled by multiple regression analysis from daily air temperature, dry-bulb saturated vapor pressure, relative humidity, atmospheric pressure, soil moisture, and soil temperature. Data was analyzed based on soil moisture levels and air temperature with annual data being grouped into either hot-humid season or relatively cool season based on the precipitation patterns. This was essential in order to acquire simplified exponential models for parameter estimation. Minimum and maximum daily mean soil CO2 effiux rates were observed in November and July, with respective rates of 1.98 ± 0.66 and 11.04 ± 0.96 μmol m^-2 s^-1 being recorded. Annual average soil CO2 emission （FCO2） was 5.92 μmol m^-2 s^-1. Including all the weather variables into the model helped to explain 73.9% of temporal variability in soil CO2 emission during the measurement period. Soil CO2 effiux increased with increasing soil temperature and soil moisture. Preliminary results showed that Q10, which is defined as the difference in respiration rates over a 10 ℃ interval, was partly explained by fine root biomass. Soil temperature and soil moisture were the dominant factors controlling soil CO2 effiux and were regarded as the driving variables for CO2 production in the soil. Including these two variables in regression models could provide a useful tool for predicting the variation of CO2 emission in the commercial forest Soils of South China .

关键词： CO2 emission lower subtropical area orchard forest ecosystem soil moisture soil temperature

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Control mechanism of a cable truss system for stability of roadways within thick coal seams

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Journal of Central South University 2017年第5期24卷 1098-1110页

作者： YAN Hong HE Fu-lian li lin-yue FENG Rui-min XING Peng-fei Key Laboratory of Deep Coal Resource Mining Ministry of Education of China (School of Mines China University of Mining & Technology) Faculty of Resources and Safety Engineering China University of Mining and Technology (Beijing) Guizhou Xinlian Blasting Engineering Group Co. Ltd. Department of Mining and Mineral Resources Engineering Southern Illinois University

Cable truss systems have been widely applied in roadways with complicated conditions, such as the large cross-sections of deep wells, and high tectonic stress. However, they are rarely applied to roadways with extremely thick coal seams because the control mechanism of the system for the deformation of the roof and the separation between coal rock segments is not completely understood. By using the relationship between the support system and the roof strata, a mechanical model was established to calculate the deformation of the roof in a thick coal seam with bedding separation under different support conditions: with an anchor truss support and without support. On this basis, the research was used to deduce a method for computing the minimum pre-tightening forces in the anchor truss, the maximum amounts of subsidence and separation with, and without, anchor truss support under the roof, and the maximum subsidence and the decreasing amounts of the separation before and after adopting the anchor truss. Additionally, mechanical relationships between the minimum pre-tightening force and the anchoring force in the anchor were analyzed. By taking a typical roadway with thick coal roof as an example, the theoretical results mentioned above were applied in the analysis and testing of a roof supporting project in a roadway field to verify the accuracy of the theory: favorable experimental results were achieved. In addition, the relationships among other parameters were analyzed, including the minimum pre-tightening forces applied by the anchor truss, the angle of inclination of the anchor cable, and the array pitch. Meanwhile, the changing characteristics of the amounts of roof separation and subsidence with key parameters of the support system(such as array pitch, pre-tightening force, and inclination angle) were also analyzed. The research results revealed the acting mechanism of the anchor truss in control of roadway stability with a thick coal seam, providing a theoretic

关键词： cable truss system thick coal seam roof separation pre-tightening force

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Long-term changes of water acidity in an intact forested watershed in south China

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Journal of Mountain Science 2021年第12期18卷 3138-3146页

作者： liU Xiao-dong FENG Ying-jie MO Qi-feng CHU Guo-wei li yue-lin ZHANG Qian-mei ZHANG Wei-qiang GAN Xian-hua ZHOU Qing College of Forestry and Landscape Architecture South China Agricultural UniversityGuangzhou 510642China South China Botanical Garden Chinese Academy of SciencesGuangzhou 510650China Guangdong Academy of Forestry Guangzhou 510520China

Acid rain is a global environmental issue and causes serious adverse impacts on natural ecosystems and human *** acid rain and its subsequent impacts have been extensively studied in temperate regions and in big cities globally,but the monitoring of acid rain in non-urban areas in subtropical region is still ***,we analyze 18 years of water acidity observations from a non-urban site in western Pearl River Delta region,south *** 2000 to 2018,annual mean precipitation pH values in the study site showed a marked increase(Plified during drier years as a strong dilution effect was detected between precipitation amount and its *** pH of surface runoff water(4.74±0.70)was significantly lower than that of precipitation as a result of the regulating effects of the highly acidified soil and the rich humus on the forest *** groundwater pH(6.32±0.63)was significantly higher than the precipitation pH especially during dry *** results of the present study indicated that the groundwater has a strong acid buffer and neutralizing effects and thus plays an important role in supplies of clean water.

关键词： Acid rain Precipitation Runoff water Groundwater Subtropical China

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Responses of Soil Acid Phosphomonoesterase Activity to Simulated Nitrogen Deposition in Three Forests of Subtropical China

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Pedosphere 2012年第5期22卷 698-706页

作者： HUANG Wen-Juan ZHANG De-Qiang li yue-lin LU XianKai ZHANG Wei HUANG Juan D.OTIENO Z.H.XU liU Ju-Xiu liU Shi-Zhong CHU Guo-Wei Key laboratory of Vegetation Restoration and Management of Degrade Ecosystems South China Botanical GardenChinese Academy of SciencesGuangzhou 510650(China) Graduate University of Chinese Academy of Sciences Beijing 100049(China) Department of Plant Ecology University of BayreuthBayreuth 95440(Germany) Environmental Futures Centre&School of Biomoleeular and Physical Sciences Griffith UniversityNathan QLD 4111(Australia)

Soil acid phosphomonoesterase activity (APA) plays a vital role in controlling phosphorus (P) cycling and reflecting the current degree of P limitation. Responses of soil APA to elevating nitrogen (N) deposition are important because of their potential applications in addressing the relationship between N and P in forest ecosystems. A study of responses of soil APA to simulated N deposition was conducted in three succession forests of subtropical China. The three forests include a Masson pine (Pinus massoniana) forest (MPF)-pioneer community, a coniferous and broad-leaved mixed forest (MF)-transition community and a monsoon evergreen broad-leaved forest (MEBF)-climax community. Four N treatments were designed for MEBF: control (without N added), low-N (50 kg N ha-1 year-1), and medium-N (100 kg N ha-1 year-1) and high-N (150 kg N ha-1 year-1), and only three N treatments (i.e., control, low-N, medium-N) were established for MPF and MF. Results showed that soil APA was highest in MEBF, followed by MPF and MF. Soil APAs in both MPF and MF were not influenced by low-N treatments but depressed in medium-N treatments. However, soil APA in MEBF exhibited negative responses to high N additions, indicating that the environment of enhanced N depositions would reduce P supply for the mature forest ecosystem. Soil APA and its responses to N additions in subtropical forests were closely related to the succession stages in the forests.

关键词： Dinghushan Biosphere Reserve forest ecosystems forest succession phosphorus limitation subtropical region

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Prediction of upper limit position of bedding separation overlying a coal roadway within an extra-thick coal seam

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Journal of Central South University 2018年第2期25卷 448-460页

作者： YAN Hong ZHANG Ji-xiong li lin-yue FENG Rui-min li Tian-tong State Key Laboratory of Coal Resource and Safe Mining Key Laboratory of Deep Coal Resource Mining of Ministry of Education of China (China University of Mining & Technology) Xuzhou 221116 China Guizhou Xinlian Blasting Engineering Group Co. Ltd Guiyang 550002 China Department of Chemical and Petroleum Engineering University of Calgary Calgary T2N 1N4 Canada

Failure of the surrounding rock around a roadway induced by roof separation is one major type of underground roof-fall *** failure can especially be commonly-seen in a bottom-driven roadway within an extra-thick coal seam("bottom-driven roadway"is used throughout for ease of reference),containing weak partings in their roof coal *** determine the upper limit position of the roof interlayer separation is the primary premise for roof *** this study,a mechanical model for predicting the interlayer separation overlying a bottom-driven roadway within an extra-thick coal seam was established and used to deduce the vertical stress,and length,of the elastic,and plastic zones in the rock strata above the wall of the roadway as well as the formulae for calculating the deflection in different regions of rock strata under bearing ***,an approach was proposed,calculating the stratum load,deflection,and limiting span of the upper limit position of the interlayer separation in a thick coal *** on the key strata control theory and its influence of bedding separation,a set of methods judging the upper limit position of the roof interlayer separation were *** addition,the theoretical prediction and field monitoring for the upper limit position of interlayer separation were conducted in a typical *** results obtained by these two methods are consistent,indicating that the methods proposed are conducive to improving roof control in a thick coal seam.

关键词： extra-thick coal seam bedding separation coal roadway roof fall mechanical model

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Stability assessment of rock surrounding an I-beam supported retreating roadway

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Journal of Central South University 2015年第9期22卷 3598-3607页

作者：严红张吉雄李林玥冯锐敏 Key Laboratory of Deep Coal Resource Mining (China University of Mining and Technology) Ministry of Education Department of Mining and Mineral Resources Engineering Southern Illinois University

The installation of a back-wall guard-board is the key to successfully supporting underground retreating roadways in coal mines. Based on the coordinate support principle, and using an I-shaped steel support for the surrounding rock, a mechanical model was developed for the stability of the roadway support and surrounding rock. Analysis of the bearing capacity of the roof back-wall guard-board and modelling of the equations for the maximum deflection and the maximum compressive stress of the top and side beams of the I-shaped steel support were undertaken. Simultaneously, the model was used to calculate and analyse the stability of the top and side beams of the I-shaped steel support structure and analyse the criteria for their stability. The results provide a reliable theoretical basis for the judgment of the stability of the surrounding rock and support structure. The theoretical evaluation results are consistent with field data. Finally, the key support parameters of the top and side beams of the I-shaped steel support structure and the variation of the maximum deflection and the maximum compressive stress as affected by the influence of the guard-board length were investigated. It is concluded that, as the back-board length increases, the maximum compressive stress in the top beam of the I-shaped steel support increases while the compressive stress in the side beam decreases. The results show that the accuracy of judgment of the stability of a supported retreating roadway is improved, providing guidance for the design of such typical I-shaped steel support and back-board structures.

关键词： mine support retreating roadway mechanical model back-wall guard-board stability assessment

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数字经济发展助力农村居民增收:作用机制与实证检验

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改革 2024年第11期 57-71页

作者：李林玥中央财经大学国际经济与贸易学院

以农村居民为研究对象,利用中国家庭追踪调查数据(CFPS)和数字经济发展指数,通过构建双向固定效应模型探究数字经济对农村居民的增收效应及其作用机制。研究发现,数字经济对农村居民具有显著的增收效应,且这一结论在替换核心解释变量、... 详细信息

以农村居民为研究对象,利用中国家庭追踪调查数据(CFPS)和数字经济发展指数,通过构建双向固定效应模型探究数字经济对农村居民的增收效应及其作用机制。研究发现,数字经济对农村居民具有显著的增收效应,且这一结论在替换核心解释变量、替换估计方法和剔除可信度低的样本进行稳健性检验后仍然成立。机制分析表明,数字经济通过提高劳动生产率、增加非农就业、促进农村居民创业、提升社会融入度四个作用路径助力农村居民收入增长。异质性分析表明,数字经济对互联网依赖度高的农村居民、农村低收入群体及东北地区农村居民的增收效应更为显著。应加强农村地区基础设施建设,强化数字化培训和教育,完善数字经济发展相关政策,发挥地方特色优势。

关键词：数字经济农村居民增收效应

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Intelligent prediction on air intake flow of spark ignition engine by a chaos radial basis function neural network

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Journal of Central South University 2020年第9期27卷 2687-2695页

作者： li yue-lin liU Bo-fu WU Gang liU Zhi-qiang DING Jing-feng ABUBAKAR Shitu Key Laboratory of Safety and Design and Reliability Technology of Engineering Vehicles in Hunan Province Changsha 410114China College of Automotive and Mechanical Engineering Changsha University of Science and TechnologyChangsha 410114China College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China

To ensure the control of the precision of air-fuel ratio(AFR)of port fuel injection(PFI)spark ignition(SI)engines,a chaos radial basis function(RBF)neural network is used to predict the air intake flow of the *** data of air intake flow is proved to be multidimensionally nonlinear and *** RBF neural network is used to train the reconstructed phase space of the *** chaos algorithm is employed to optimize the weights of output layer connection and the radial basis center of Gaussian function in hidden *** simulation results obtained from Matlab/Simulink illustrate that the model has higher accuracy compared to the conventional RBF *** mean absolute error and the mean relative error of the chaos RBF model can reach 0.0017 and 0.48,respectively.

关键词： intake air flow spark ignition engine chaos RBF neural network

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三黄糖肾康颗粒对早期糖尿病肾病模型大鼠微炎症状态的影响

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中国全科医学 2017年第30期20卷 3770-3775页

作者：奚悦李敬林锦州医科大学附属第三医院辽宁省锦州市121000 辽宁中医药大学辽宁省沈阳市110032

目的探讨三黄糖肾康颗粒对早期糖尿病肾病模型大鼠微炎症状态的影响。方法研究时间为2012年8—10月,SPF级Wistar大鼠90只,雌雄各半,随机选取10只作为正常对照组,给予常规颗粒饲料喂养;其余80只随机分为模型组、西药组、中药预防组、中... 详细信息

目的探讨三黄糖肾康颗粒对早期糖尿病肾病模型大鼠微炎症状态的影响。方法研究时间为2012年8—10月,SPF级Wistar大鼠90只,雌雄各半,随机选取10只作为正常对照组,给予常规颗粒饲料喂养;其余80只随机分为模型组、西药组、中药预防组、中药低剂量组、中药高剂量组,各16只,均给予高脂高糖饲料喂养。1周后除正常对照组大鼠外其余各组大鼠均予以链脲佐菌素(STZ)溶液42 mg/kg一次性腹腔注射,诱导糖尿病模型,8只大鼠造模失败;余72只大鼠2周后收集24 h尿液检测尿微量清蛋白(MALB)以判定早期糖尿病肾病模型是否成功,其中6只大鼠糖尿病肾病模型造模失败。实验过程中,模型组3只大鼠死亡,西药组1只大鼠死亡,中药低剂量组、中药高剂量组各有2只大鼠死亡。正常对照组和模型组均给予蒸馏水灌胃,中药预防组大鼠自早期糖尿病肾病造模成功日起即开始给药,连续给药10周;其余各组造模成功2周后,分别给予相应药物灌胃,连续给药8周。西药组给予贝那普利灌胃,中药高剂量组使用浓度为3.84 g/ml的三黄糖肾康颗粒药液,中药预防组和中药低剂量组使用浓度为1.28 g/ml的三黄糖肾康颗粒药液。实验结束后测定大鼠血糖(FBG)、糖化血红蛋白(HbA_(1c))、MALB、血清β2-微球蛋白(β2-MG)、血肌酐(Scr)、尿素氮(BUN)、血清及肾脏组织中C反应蛋白(CRP),肾脏组织中核因子κB(NF-κB)、单核细胞趋化蛋白-1(MCP-1)、细胞表面趋化因子受体2(CCR2)mRNA及蛋白表达水平,光镜下观察肾脏组织形态变化(HE染色和PAS染色)。结果模型组、西药组、中药预防组、中药低剂量组、中药高剂量组FBG、HbA_(1c)、MALB高于正常对照组(P<0.01);西药组、中药预防组、中药低剂量组、中药高剂量组FBG、HbA_(1c)、MALB、血清及肾脏组织中CRP,肾脏组织中NF-κB、MCP-1、CCR2 mRNA及蛋白表达水平均低于模型组(P<0.01);中药预防组FBG、MALB低于西药组、中药低剂量组、中药高剂量组(P<0.05)。正常对照组、西药组、中药预防组、中药低剂量组、中药高剂量组大鼠BUN低于模型组(P<0.01);中药低剂量组大鼠BUN高于正常对照组(P<0.05)。模型组大鼠血清及肾脏组织中CRP,肾脏组织中NF-κB、MCP-1、CCR2 mRNA及蛋白表达水平均高于正常对照组(P<0.01)。中药低剂量组、中药高剂量组大鼠肾脏组织中NF-κB mRNA及蛋白表达水平均高于中药预防组(P<0.01)。西药组大鼠肾脏组织中NF-κB mRNA及蛋白表达水平高于中药预防组、而低于中药低剂量组(P<0.01)。中药预防组大鼠肾脏组织中MCP-1、CCR2 mRNA及蛋白表达水平低于西药组及中药低、高剂量组(P<0.05);西药组MCP-1、CCR2 mRNA及蛋白表达水平低于中药低、高剂量组(P<0.05)。西药组、中药预防组、中药低剂量组、中药高剂量组大鼠肾脏病理变化程度明显轻于模型组。结论三黄糖肾康颗粒可有效降低糖尿病肾病模型大鼠FBG、HbA_(1c)、MALB、BUN、血清及肾脏组织中CRP,下调肾脏组织NF-κB、MCP-1、CCR2 mRNA及蛋白表达水平,改善肾脏形态学病变,减轻糖尿病肾病微炎症状态。

关键词：糖尿病肾病大鼠炎症三黄糖肾康

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东亚对外开放与全要素生产率:只是线性关系吗?

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数学的实践与认识 2020年第1期50卷 72-82页

作者：雷钦礼李粤麟暨南大学经济学院统计学系广东广州510632

为研究东亚对外开放对全要素生产率的影响,分别使用出口占比,进口占比和FDI三项指标测度对外开放程度,并采用普通面板模型和空间面板模型进行回归分析以保障结果的稳健性.结果表明:进口占比,FDI对TFP呈倒"U"型非线性影响,而出口占比的... 详细信息

为研究东亚对外开放对全要素生产率的影响,分别使用出口占比,进口占比和FDI三项指标测度对外开放程度,并采用普通面板模型和空间面板模型进行回归分析以保障结果的稳健性.结果表明:进口占比,FDI对TFP呈倒"U"型非线性影响,而出口占比的增加使得TFP下降,这就解释了为什么东亚地区虽然开放程度较高但是全要素生产率不高甚至会出现负增长;空间溢出效应有利于东亚地区全要素生产率增长,因此加强东亚地区区域间的联系,是增加全要素生产率一个有效途径.

关键词：对外开放全要素生产率空间溢出效应

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