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Single-Index Quantile Regression with Left Truncated Data

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Journal of Systems Science & Complexity 2022年第5期35卷 1963-1987页

作者： XU Hongxia FAN Guoliang li jinchang Department of Mathematics Shanghai Maritime UniversityShanghai 201306China School of Data Sciences Zhejiang University of Finance and EconomicsHangzhou 310018China School of Economics and Management Shanghai Maritime UniversityShanghai 201306China

The purpose of this paper is two ***,the authors investigate quantile regression(QR)estimation for single-index QR models when the response is subject to random left *** random weights are introduced to deal with left truncated data and the associated iteration estimation method is *** asymptotic properties for the proposed QR estimates of the index parameter and unknown link function are both ***,by combining the QR loss function and the adaptive LASSO penalization,a variable selection procedure for the index parameter is introduced and its oracle property is ***,a weighted empirical log-likelihood ratio of the index parameter based on the QR method is introduced and is proved to be asymptotic standard chi-square ***,confidence regions of the index parameter can be *** finite sample performance of the proposed methods are demonstrated.A real data analysis is also conducted to show the usefulness of the proposed approaches.

关键词： Adaptive LASSO penalty left truncated data quantile regression single-index model variable selection

Simulating the effect of wind erosion on aeolian desertification process of Horqin sandy land and its significance on material cycle:a wind tunnel study

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Research in Cold and Arid Regions 2022年第1期14卷 43-53页

作者： CaiXia Zhang jinchang li Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China Shanxi Laboratory for Yellow River Institute of Loess PlateauShanxi UniversityTaiyuanShanxi 030006China

Samples from the Horqin sandy land were exposed to a series of wind velocities,and sink particles were collected at the end of the diffusion section of a wind *** sizes of collected samples show great variation because of the granularity difference of the surface *** original samples show lower average content of SiO_(2) and higher average content of Al _(2)O_(3),Fe_(2)O_(3),MgO,CaO,Na_(2)O,and K_(2)O than collected *** with other dust source areas in China,the Horqin sandy land had higher content of Zr,Ba,SiO_(2),Al_(2)O_(3) and K_(2)*** with the average upper continental crust(UCC)composition,surface samples were rich in the content of Y,Zr,Nb,Ba,La,*** characteristics of fine grain components of the Horqin sandy land differ from those from other dust source regions,because fine-grained particles in the Horqin sandy land were mostly derived from various local deposits formed in its unique depositional environments influenced by several tectonic activities.

关键词： sink sand wind erosion aeolian process Horqin sandy land

Heavy Metal Contamination of Agricultural Soils in Taiyuan, China

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Pedosphere 2015年第6期25卷 901-909页

作者： liU Yong WANG Huifeng li Xiaoting li jinchang Institute of Loess Plateau Shanxi University

To evaluate the current state of the environmental quality of agricultural soils in Taiyuan City, a hotspot for China's industrial development, the concentrations of 8 heavy metals in soils were investigated by means of extensive sampling in farmlands, forestlands,and grasslands in the city. Statistical analyses and spatial distribution maps were used to identify the most significant heavy metal pollutants. The mean concentrations of As, Cd, Cu, Hg, Pb, Zn, Ni, and Cr were slightly higher than their background values in Taiyuan's topsoil, but were lower than the maximum permissible concentrations in the Chinese Environmental Quality Standard for agricultural soils. Farmland soils in Taiyuan had the highest average Cd, Cu, Hg, Pb, Zn, and Cr concentrations, but the As and Ni concentrations did not differ significantly among the farmland, forestland, and grasslands. Soil contamination by Cd, Cu, Hg, Pb,Zn, and Cr was mainly derived from farming practices, especially the use of sewage water for irrigation. In contrast, As and Ni might derive mainly from the soil parent material. The identification of heavy metal sources in agricultural soils may provide a basis for taking appropriate action to protect soil quality.

关键词： environmental pollution farming practices sewage irrigation soil parent material soil quality

Engineering Thermoelectric Performance of α-GeTe by Ferroelectric Distortion

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Energy & Environmental Materials 2024年第2期7卷 175-183页

作者： Yuting Fan Chenghao Xie Jun li Xiangyu Meng jinchang Sun Jinsong Wu Xinfeng Tang Gangjian Tan State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology International School of Materials Science and Engineering Wuhan University of Technology

The rhombohedral α-Ge Te can be approximated as a slightly distorted rocksalt structure along its [1 1 1] direction and possesses superb thermoelectric performance. However, the role of such a ferroelectric-like structural distortion on its transport properties remains unclear. Herein, we performed a systematic study on the crystal structure and electronic band structure evolutions of Ge1-xSnxTe alloys where the degree of ferroelectric distortion is continuously tuned. It is revealed that the band gap is maximized while multiple valence bands are converged at x = 0.6, where the ferroelectric distortion is the least but still works. Once undistorted, the band gap is considerably reduced, and the valence bands are largely separated ***, near the ferro-to-paraelectric phase transition Curie temperature,the lattice thermal conductivity reaches its minima because of significant lattice softening enabled by ferroelectric instability. We predict a peak ZT value of 2.6 at 673 K in α-Ge Te by use of proper dopants which are powerful in suppressing the excess hole concentrations but meanwhile exert little influence on the ferroelectric distortion.

关键词： electronic band structures ferroelectric distortion lattice softening thermoelectric α-GeTe

Changes in wind activity from 1957 to 2011 and their possible influence on aeolian desertification in northern China

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Journal of Arid Land 2015年第6期7卷 755-764页

作者： li jinchang liU Haixia SU Zhizhu FAN Xiaohui State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Institute of Loess Plateau Shanxi University Historical Culture School Shanxi University

Wind activity is proved to have significant impacts on aeolian desertification. Clarifying the fluctuations and change trend of wind velocity is important for understanding their influence on aeolian desertification. In this study, we used a dataset of wind velocities collected from 93 meteorological stations across northern China from 1957 to 2011 to analyze the changes in wind activity during this period. We tested the monotonic and step（abrupt） trends for annual and seasonal data of mean wind velocity by using Mann-Kendall and Mann-Whitney tests, respectively. The results indicated that the annual mean wind velocity decreased by 0.83 m/s from 1957 to 2011. The decreasing trends were also significant（P〈0.01） for each season. The magnitude of the decrease was smallest in the east of northern China and largest in the west of northern China, and the most remarkable decrease occurred in the northwest of northern China. Abrupt decreases in annual and seasonal mean wind velocities occurred in the mid-1980 s, which was consistent with the changes in aeolian desertification since the mid-1980 s in northern China. As revealed by our study, although both modern aeolian desertification and ecosystem rehabilitation are affected by human activities to some extent, they are also likely to be strongly controlled by climate change, especially by wind activity.

关键词： wind velocity monotonic trend step trend aeolian desertification northern China

Elemental composition and its environmental significance for the varicolored hills in the northern foothills of the Qilian Mountains of Sunan Yugur Autonomous County,China

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Research in Cold and Arid Regions 2015年第3期7卷 257-264页

作者： CaiXia Zhang XiaoZe li Zhong Sun jinchang li Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Institute of Loess Plateau Shanxi University

The varicolored hills in the northern foothills of the Qilian Mountains of northem China, in the Hexi Corridor of Gansu Province＇s Sunan Yugur Autonomous County, have given this region a unique geomorphology. In this paper, we describe the elemental composition, lithological characteristics, and source type of the sediments that formed the varicolored hills. We found that the major oxides that make up their sediments are SiO2, A12O3 and Na2O. These sediments had higher Fe2O3, MgO, CaO, and Na2O contents and lower SiO2, A12O3, K2O, and TiO2 contents than in the major Fangyan rock group of the Jianglang Mountains Danxia landform and the red paleosols that have accumulated in the Yaojia Formation of the Songliao Basin. The varicolored hills have developed their strong coloration as a result of oxidation or reduction of Fe. Our data suggest that the sediments developed from terrestrial detrital *** varicolored hills in the northern foothills of the Qilian Mountains of northem China, in the Hexi Corridor of Gansu Province＇s Sunan Yugur Autonomous County, have given this region a unique geomorphology. In this paper, we describe the elemental composition, lithological characteristics, and source type of the sediments that formed the varicolored hills. We found that the major oxides that make up their sediments are SiO2, A12O3 and Na2O. These sediments had higher Fe2O3, MgO, CaO, and Na2O contents and lower SiO2, A12O3, K2O, and TiO2 contents than in the major Fangyan rock group of the Jianglang Mountains Danxia landform and the red paleosols that have accumulated in the Yaojia Formation of the Songliao Basin. The varicolored hills have developed their strong coloration as a result of oxidation or reduction of Fe. Our data suggest that the sediments developed from terrestrial detrital deposits.

关键词： red bed varicolored hills Hexi Corridor Qilian Mountains

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共同富裕统计监测评价探讨

统计研究 2022年第2期39卷 3-17页

作者：李金昌余卫浙江财经大学党委中国统计学会中国统计教育学会国家统计专家咨询委员会浙江财经大学数据科学学院

到本世纪中叶我国将基本实现全体人民的共同富裕。那么,何为共同富裕?哪些因素是影响共同富裕的主要因素?哪些指标能够体现共同富裕特征?如何监测共同富裕进程?这些问题有必要从统计上进行科学的解读。本文梳理了国内外关于共同富裕的... 详细信息

到本世纪中叶我国将基本实现全体人民的共同富裕。那么,何为共同富裕?哪些因素是影响共同富裕的主要因素?哪些指标能够体现共同富裕特征?如何监测共同富裕进程?这些问题有必要从统计上进行科学的解读。本文梳理了国内外关于共同富裕的相关论述和国外关于反贫困的有关讨论,在解读新时代共同富裕内涵的基础上,以“以人民为中心”和“共享、富裕、可持续”为要点,紧扣“共同”和“富裕”两大关键词,瞄准城乡、地区和收入三个差距,构建了由经济质效并增、发展协调平衡、精神生活丰富、全域美丽建设、社会和谐和睦与公共服务优享六个一级指标组成的共同富裕过程性评价指标体系和由共享性、富裕度和可持续性三个一级指标组成的共同富裕结果性评价指标体系,最后以浙江省为例测度了2015-2020年浙江省共同富裕实现程度。

关键词：共同富裕统计解读高质量发展指标体系

“双碳”愿景下企业绿色转型的破局之道——数字化驱动绿色化的实证研究

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数量经济技术经济研究 2023年第9期40卷 27-49页

作者：李金昌连港慧徐蔼婷浙江工商大学统计与数学学院

在“双碳”战略目标和可持续发展背景下,企业亟须将数字化转型作为实现绿色发展、解决制度和效率困境的“破局”关键。本文尝试在深度解读企业绿色转型内涵的基础上,解构数字化转型驱动绿色转型的作用机理。基于2009~2021年中国上市公... 详细信息

在“双碳”战略目标和可持续发展背景下,企业亟须将数字化转型作为实现绿色发展、解决制度和效率困境的“破局”关键。本文尝试在深度解读企业绿色转型内涵的基础上,解构数字化转型驱动绿色转型的作用机理。基于2009~2021年中国上市公司样本数据实证发现,企业数字化转型对环境绩效、经济绩效和绿色创新绩效均具有显著的正向影响。这意味着,企业数字化转型能够显著促进绿色转型。异质性分析表明,当区域环境规制强度较高时,企业数字化转型的驱动效应更强;相较于非重污染企业,重污染企业基于多方压力而更具绿色转型内生动机,从而在一定程度上削弱了数字化转型的驱动作用。从作用路径看,企业数字化转型通过提升内部能力建设、增强市场外部关注、吸引政府补贴三种途径促进绿色转型。从政策层面看,低碳城市试点在数字化转型对绿色转型的作用机制中发挥一定的正向激励作用,但“双碳”目标囿于提出时间较短,其激励作用尚未显现。本文拓展了绿色转型的研究视角,为企业数字化与绿色化“双转型”融合研究提供了新思路,为“双碳”愿景下中国企业实现数字化绿色化协同转型提供了路径选择。

关键词：数字化转型绿色转型环境绩效经济绩效绿色创新绩效

Land use and land cover change processes in China's eastern Loess Plateau

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Research in Cold and Arid Regions 2015年第6期7卷 722-729页

作者： jinchang li HaiXia liu Yong liu ZhiZhu Su ZiQiang Du Institute of Loess Plateau Shanxi University Historical Culture School Shanxi University

Using Landsat remote sensing images, we analyzed changes in each land use type and transitions among different land use types during land use and land cover change （LUCC） in Ningwu County, located in the eastern Loess Plateau of China, from 1990 to 2010. We found that grassland, woodland, and farmland were the main land use types in the study area, and the area of each type changed slightly from 1990 to 2010, whereas the area of water, construction land, and unused land increased greatly. For the whole area, the net change and total change were insignificant due to weak human activity intensity in most of the study area, and the LUCC was dominated by quasi-balanced two-way transitions from 1990 to 2010. The insignificant overall amount of LUCC appears to have resulted from offsetting of rapid increases in population, economic growth, and the im- plementation of a program to return farmland to woodland and grassland in 2000. This program converted more farmland into woodland and grassland from 2000 to 2010 than from 1990 to 2000, but reclamation of woodland and grassland for use as farmland continued from 2000 to 2010, and is a cause for concern to the local government.

关键词： land use and land cover change remote sensing forest restoration Ningwu County Loess Plateau