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Spatial and Temporal Distribution of PM

Xiao-hong Chen,Xiang-bo Tang

《工程管理前沿（英文）》 2016年第3卷第2期页码 171-181 doi: 10.15302/J-FEM-2016017

摘要： Utilizing the initial hourly monitoring data of PM concentrations at 23 monitoring sites across the Chang-Zhu-Tan city cluster between January 2013 and February 2014 that released in Real-time Air Quality Reporting System in Hunan Province, this paper draws diagrams and analyzes the change rule of the pollutants concentration over time. In addition, this paper studies the regional distribution of PM seasonal pollution in the vicinity of the monitoring sites using ArcGIS geographic information system with the Kriging interpolation method. On this basis, this paper puts forward some effective control strategies to cope with regional PM pollution combined with the information of industry distribution and development status in the Chang-Zhu-Tan city cluster.

关键词： PM_2.5 spatial and temporal distribution ArcGIS the chang-Zhu-Tan city cluster

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基于惯性能时空最优分布的高加速轻载机构精密定位方法 Article

陈新,白有盾,杨志军,高健,陈贡发

《工程（英文）》 2015年第1卷第3期页码 391-398 doi: 10.15302/J-ENG-2015063

摘要：

高速运动精密定位是微电子封装设备中高加速轻载执行机构的基本运动需求。本文推导了高加速机构瞬态非线性动力学响应方程，揭示了刚度、频率、阻尼 (与材料空间布局相关) 和驱动频率 (与运动规划相关) 是主要影响因素。据此，在满足高加速机构精密定位的条件下，笔者提出了一种基于最优非线性动力学响应的结构优化和速度规划新方法。在结构优化中，首先分析了目前流行的基于等效静态载荷的柔性多体动力学优化方法未充分考虑惯性载荷的不足，然后提出了基于等效模态的柔性多体动力学最优动态响应优化新方法；在速度规划上，针对传统的几何光滑方法不能反映系统动态特性的缺陷，提出了基于变边界条件非线性动力学响应优化的速度规划新方法。将所提方法应用到高速固晶焊头的优化设计中，通过结构优化，降低振幅超过20%，再经非对称变加速规划，缩短定位时间超过40%。本文提出的方法为微电子封装类装备等高加速轻载机构精密定位的实现提供了有效的理论支撑和解决途径。

关键词：高加速轻载机构精密定位时空分布惯性能等效静态载荷方法速度规划

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Industrial eco-efficiency and its spatial-temporal differentiation in China

Wei YANG, Fengjun JIN, Chengjin WANG, Chen LV

《环境科学与工程前沿（英文）》 2012年第6卷第4期页码 559-568 doi: 10.1007/s11783-012-0400-4

摘要： The aim of this paper is to study the spatial-temporal differentiation of industrial eco-efficiency in China. Using methods based on the data envelopment analysis (DEA) model and exploratory spatial data analysis (ESDA) and data from 1985, 1995, 2005, and 2008 of 30 provinces in China, the spatial-temporal pattern changes in industrial eco-efficiency are discussed. The results show that: first, the patterns of industrial eco-efficiency are dominated by clustering of relatively low efficiency provinces; second, spatial relationships between the industrial eco-efficiencies of different provinces changed slightly throughout the period and the provinces persistently exhibit spatial concentration of relatively low industrial eco-efficiency; finally, there is an obvious trend in the polarization of industrial eco-efficiency, i.e., the higher level spatial units are concentrated in eastern China, and the lower level spatial units are mainly in western and central China.

关键词： industrial eco-efficiency data envelopment analysis (DEA) model exploratory spatial data analysis (ESDA)

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Assessment of temporal and spatial variations in water quality using multivariate statistical methods

Xue LI,Pengjing LI,Dong WANG,Yuqiu WANG

《环境科学与工程前沿（英文）》 2014年第8卷第6期页码 895-904 doi: 10.1007/s11783-014-0736-z

摘要： This study evaluated the temporal and spatial variations of water quality data sets for the Xin'anjiang River through the use of multivariate statistical techniques, including cluster analysis (CA), discriminant analysis (DA), correlation analysis, and principal component analysis (PCA). The water samples, measured by ten parameters, were collected every month for three years (2008–2010) from eight sampling stations located along the river. The hierarchical CA classified the 12 months into three periods (First, Second and Third Period) and the eight sampling sites into three groups (Groups 1, 2 and 3) based on seasonal differences and various pollution levels caused by physicochemical properties and anthropogenic activities. DA identified three significant parameters (temperature, pH and ) to distinguish temporal groups with close to 76% correct assignment. The DA also discovered five parameters (temperature, electricity conductivity, total nitrogen, chemical oxygen demand and total phosphorus) for spatial variation analysis, with 80.56% correct assignment. The non–parametric correlation coefficient (Spearman R) explained the relationship between the water quality parameters and the basin characteristics, and the GIS made the results visual and direct. The PCA identified four PCs for Groups 1 and 2, and three PCs for Group 3. These PCs captured 68.94%, 67.48% and 70.35% of the total variance of Groups 1, 2 and 3, respectively. Although natural pollution affects the Xin'anjiang River, the main sources of pollution included agricultural activities, industrial waste, and domestic wastewater.

关键词： Xin'anjiang River multivariable statistical analysis temporal variation spatial variation water quality

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Abundance, spatial distribution, and physical characteristics of microplastics in stormwater detention

《环境科学与工程前沿（英文）》 2023年第17卷第10期 doi: 10.1007/s11783-023-1724-y

摘要： Despite extensive research on microplastics (MP) in marine environments, little is known about MP abundance and transport in terrestrial systems. There is, therefore, still little understanding of the main mechanisms driving the substantial transport of MP across different environmental compartments. Storm events can transport MP beyond boundaries, such as from the land to groundwater or the ocean, as has already been discovered for organic carbon transport. Urban stormwater detention ponds are suitable environments to study the impact of stormwater on the environmental fate and transport of MP. Herein, we investigate the longitudinal and vertical distribution of MP within two detention ponds with different physical characteristics. Soil samples were collected at various locations and from multiple depths (surface and subsurface layers) for measuring MP concentrations using fluorescence microscopy. Our findings show that MP are retained more near the inlet of the ponds, and MP of larger sizes were found more abundantly near inlets than outlets. We also found that MP mass and sizes decrease from surface soil to subsurface soil. In the pond, where vegetation (grass root network) was more considerable, MP were found more evenly distributed along the depth. In terms of shape, the fragments were the most abundant MP shape.

关键词： Microplastic Environmental transport Soil pollution Stormwater Detention ponds

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空中交通延误传播动力学的时空网络视角 Article

Qing Cai, Sameer Alam, Vu N. Duong

《工程（英文）》 2021年第7卷第4期页码 452-464 doi: 10.1016/j.eng.2020.05.027

摘要：

由于日益增长的空中交通需求与有限的空域容量之间的不平衡，空中交通出现了难以解决的延误。由于空中交通与复杂的航空运输系统有关，延误可以在这些系统中被放大和传播，从而导致所谓的延迟传播的紧急行为。对延误传播动力学的理解与现代空中交通管理有着密切的关系。本文提出了一种复杂的网络延迟传播动力学观点。具体来说，我们利用以机场为节点的时空网络对空中交通场景进行建模。为了建立节点间的动态边缘，我们提出了一种时延传播方法，并将其应用于给定的空中交通调度集合。基于所构建的时空网络，提出了三个指标（幅度、严重性和速度）来衡量延迟传播动态。为了验证该方法的有效性，我们对东南亚地区（SAR）和美国的国内航班进行了案例研究。实验表明，美国交通延误传播影响的航班数和传播延迟量的传播幅度分别是SAR的5倍和10倍。实验进一步表明，美国交通的传播速度比SAR快8倍。延迟传播动态显示，SAR约6个枢纽机场存在明显的传播延误，而美国的情况则更为严重，相应数量在16个左右。本工作为跟踪空中交通延误的演变提供了有力的工具。

关键词：空中交通运输系统时延传播动力学时空网络

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Temporal and spatial stability of the EM/PM molecular subtypes in adult diffuse glioma

《医学前沿（英文）》 2023年第17卷第2期页码 240-262 doi: 10.1007/s11684-022-0936-z

摘要： Detailed characterizations of genomic alterations have not identified subtype-specific vulnerabilities in adult gliomas. Mapping gliomas into developmental programs may uncover new vulnerabilities that are not strictly related to genomic alterations. After identifying conserved gene modules co-expressed with EGFR or PDGFRA (EM or PM), we recently proposed an EM/PM classification scheme for adult gliomas in a histological subtype- and grade-independent manner. By using cohorts of bulk samples, paired primary and recurrent samples, multi-region samples from the same glioma, single-cell RNA-seq samples, and clinical samples, we here demonstrate the temporal and spatial stability of the EM and PM subtypes. The EM and PM subtypes, which progress in a subtype-specific mode, are robustly maintained in paired longitudinal samples. Elevated activities of cell proliferation, genomic instability and microenvironment, rather than subtype switching, mark recurrent gliomas. Within individual gliomas, the EM/PM subtype was preserved across regions and single cells. Malignant cells in the EM and PM gliomas were correlated to neural stem cell and oligodendrocyte progenitor cell compartment, respectively. Thus, while genetic makeup may change during progression and/or within different tumor areas, adult gliomas evolve within a neurodevelopmental framework of the EM and PM molecular subtypes. The dysregulated developmental pathways embedded in these molecular subtypes may contain subtype-specific vulnerabilities.

关键词： glioma progression molecular classification EM/PM subtyping intratumor heterogeneity

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Changes in hourly precipitation may explain the sharp reduction of discharge in the middle reach of the Yellow River after 2000

Lin LUO, Zhongjing WANG

《环境科学与工程前沿（英文）》 2013年第7卷第5期页码 756-768 doi: 10.1007/s11783-013-0563-7

摘要： The Hekou-Longmen reach, together with local floods, is the main source area for coarse sedimentations into the Yellow River. When total rainfall slightly increased in the area, discharge dramatically decreased by 40%–70% after the year of 2000, and attracting extensive attention in the context of global climate change. High temporal resolution precipitation (timescales between 1 and 4 h) data from the June to September period from 270 rain gauges over the past three decades was mined in order to help explain the phenomenon. Each rainfall event was classified as light/moderate rain, large rain, heavy rain or rainstorm by the event’s rainfall amount, and further classified as low intensity rain, medium intensity rain and high intensity rain by the event’s rainfall intensity. The Mann-Kendall trend test was applied to detect the presence and significance of monotonic trends, and to find the change points in the mean and variance of the precipitation characteristics series, including the amount, intensity, frequency and duration of each rainfall category. Results show that although the total amount of precipitation has slightly increased, the average rainfall intensity has significantly decreased. The larger change happened in light/moderate rain events and low/medium intensity rain events, and the intensity changes have a great extent occurred around the threshold of Non-Runoff Rainfall regime, which was proposed for the approximate calculation of initial losses. Changes in rainfall distribution between different classes of the Runoff Rainfall regime in the 2000s could lead to 0.9 mm less runoff depth (17.3% of the total reduction) than the 1980–1999 period. The study indicates that changes in hourly precipitation may be responsible for the sharp reduction of discharge.

关键词： precipitation intensity Mann-Kendall rank statistic spatial and temporal distribution climatic change

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Allocation of grassland, livestock and arable based on the spatial and temporal analysis for food demand

Huilong LIN, Ruichao LI, Yifan LIU, Jingrong ZHANG, Jizhou REN

《农业科学与工程前沿（英文）》 2017年第4卷第1期页码 69-80 doi: 10.15302/J-FASE-2017140

摘要： To explore the distribution of food demand and the projected trend in future food demand in China, this paper analyzed the change in current (1998–2012) per-capita demand for grain, grain-consuming and herbivorous livestock products, and predicted the food demand in 2020. The results indicated that in 1998–2012, the national per-capita consumption of grain ration declined by about 36.66%, and the per-capita consumption of grain-consu-ming and herbivorous livestock products increased by about 48% and 34.09%, respectively. The grain-consu-ming livestock products have become the primary source of both calories and protein for consumers. The proportion of herbivorous livestock products in consumer diets has increased steadily and there has been huge potential in substituting beef and mutton for pork in this dynamic market. The demand for food in different provinces of China is highly variable, which is important for planning grassland agriculture development and ensuring food safety. The demand for grain, and grain-consuming and herbivorous livestock products will increase by about 3.3%, 20% and 14% respectively by 2020. Based on the food demand and trend in the development of grassland agriculture, the 31 provinces in China are divided into three priority groups for grassland agriculture development.

关键词： arable land equivalent unit (ALEU) food equivalent unit (FEU) food security grassland agriculture time trend prediction

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Spatial distribution of phosphorus forms in sediments with different distances to the estuary of the

Shaoyong LU, Xiangcan JIN, Fengchang WU, Jing SI, Jianning GUO,

《环境科学与工程前沿（英文）》 2010年第4卷第3期页码 295-300 doi: 10.1007/s11783-010-0231-0

摘要： Effects of human activity on the distribution of phosphorus (P) forms were investigated for the sediments and porewaters in Daqinghe Estuary of Dianchi Lake, China. The concentrations of total P (TP), inorganic-P (I-P), and organic-P (Org-P), and the ratio of iron-bound P (Fe-P)/calcium-bound P (Ca-P) in the sediments decreased with the increasing distance from the sampling site to the estuary. This is probably due to the flocculant materials, e.g., ferric and aluminous salts, usually being added in the wastewater treatment processes. The concentration of ammonia in the sediment porewaters significantly decreased with the increasing distance from the sampling site to the estuary. Both concentrations of total nitrogen and nitrogen in the sediment porewaters decreased to some content with the increasing distance from the sampling site to the estuary. However, the concentrations of nitrate, dissolved total P (DTP), and TP did not have strong relationship with the distances from the sampling sites to the estuary. Pollution load and water quantity also had an important influence on the concentrations of P in sediments and its interstitial water in estuary sedimentary area.

关键词： estuary sedimentary area phosphorus (P) spatial distribution human activity the Dianchi Lake

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Spatial prediction of soil contamination based on machine learning: a review

《环境科学与工程前沿（英文）》 2023年第17卷第8期 doi: 10.1007/s11783-023-1693-1

摘要：

● A review of machine learning (ML) for spatial prediction of soil contamination.

关键词： Soil contamination Machine learning Prediction Spatial distribution

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PyLUR: Efficient software for land use regression modeling the spatial distribution of air pollutants

Xuying Ma, Ian Longley, Jennifer Salmond, Jay Gao

《环境科学与工程前沿（英文）》 2020年第14卷第3期 doi: 10.1007/s11783-020-1221-5

摘要： PyLUR comprises four modules for developing and applying a LUR model. It considers both conventional and novel potential predictor variables. GDAL/OGR libraries are used to do spatial analysis in the modeling and prediction. Developed on Python platform, PyLUR is rather efficient in data processing. Land use regression (LUR) models have been widely used in air pollution modeling. This regression-based approach estimates the ambient pollutant concentrations at un-sampled points of interest by considering the relationship between ambient concentrations and several predictor variables selected from the surrounding environment. Although conceptually quite simple, its successful implementation requires detailed knowledge of the area, expertise in GIS, statistics, and programming skills, which makes this modeling approach relatively inaccessible to novice users. In this contribution, we present a LUR modeling and pollution-mapping software named PyLUR. It uses GDAL/OGR libraries based on the Python platform and can build a LUR model and generate pollutant concentration maps efficiently. This self-developed software comprises four modules: a potential predictor variable generation module, a regression modeling module, a model validation module, and a prediction and mapping module. The performance of the newly developed PyLUR is compared to an existing LUR modeling software called RLUR (with similar functions implemented on R language platform) in terms of model accuracy, processing efficiency and software stability. The results show that PyLUR out-performs RLUR for modeling in the Bradford and Auckland case studies examined. Furthermore, PyLUR is much more efficient in data processing and it has a capability to handle detailed GIS input data.

关键词： LUR Air pollution modelling GIS spatial analysis GDAL/OGR Python Pollutant concentration mapping

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Trends of environmental accidents and impact factors in China

Pengli XUE, Weihua ZENG

《环境科学与工程前沿（英文）》 2011年第5卷第2期页码 266-276 doi: 10.1007/s11783-010-0267-1

摘要： An overview of the spatial and temporal variations of the environmental accidents in China in recent years was presented in this paper using available data. The results showed that the frequency of pollution accidents was significantly decreased, from 3462 in 1990 to 462 in 2007. The water and air pollution accidents were found to be the dominant types, accounting for more than 80% of the total accidents. Considering the classification of environmental accidents at 4 scales, the general environmental accident, i.e., the least serious type, was the most frequent event, taking up 58.98% of the total pollution accidents. In addition, the distribution of environmental accidents was generally in accordance with the industrial layout in the country during the past decade. It is very important to note that the extraordinarily severe environmental accidents showed an increasing trend in underdeveloped regions, which was caused by the transfer and the development of heavy polluted industry in these areas. As to the losses of environmental accidents, the casualties presented an obvious reduction tendency, while the direct economic loss per accident tended to climb up. Furthermore, some key factors that affect the spatial and temporal tendencies of environmental accidents in China were discussed and some suggestions were put forward, hoping to shed light on environmental risk management and emergency plans making associated with environmental accidents in China.

关键词： environmental accidents spatial and temporal trends environmental risk

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Digital representation of meso-geomaterial spatial distribution and associated numerical analysis of

YUE Zhongqi

《结构与土木工程前沿（英文）》 2007年第1卷第1期页码 80-93 doi: 10.1007/s11709-007-0008-0

摘要： This paper presents the author's efforts in the past decade for the establishment of a practical approach of digital representation of the geomaterial distribution of different minerals, particulars, and components in the meso-scale range (0.1 to 500 mm). The primary goal of the approach is to provide a possible solution to solve the two intrinsic problems associated with the current main-stream methods for geomechanics. The problems are (1) the constitutive models and parameters of soils and rocks cannot be given accurately in geomechanical prediction; and (2) there are numerous constitutive models of soils and rocks in the literature. The problems are possibly caused by the homogenization or averaging method in analyzing laboratory test results for establishing the constitutive models and parameters. The averaging method employs an assumption that the test samples can be represented by a homogeneous medium. Such averaging method ignores the fact that the geomaterial samples are also consisted of a number of materials and components whose properties may have significant differences. In the proposed approach, digital image processing methods are used as measurement tools to construct a digital representation for the actual spatial distribution of the different materials and components in geomaterial samples. The digital data are further processed to automatically generate meshes or grids for numerical analysis. These meshes or grids can be easily incorporated into existing numerical software packages for further mechanical analysis and failure prediction of the geomaterials under external loading. The paper presents case studies to illustrate the proposed approach. Further discussions are also made on how to use the proposed approach to develop the geomechanics by taking into account the geomaterial behavior at micro-scale, meso-scale and macro-scale levels. A literature review of the related developments is given by examining the SCI papers in the database of Science Citation Index Expanded. The results of this review have shown that the proposed approach is one of the latest research and developments in geomechanics where actual spatial distribution and properties of materials and components at the meso-level are taken into account.

关键词： homogeneous numerical analysis Expanded homogenization meso-level

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High resolution satellite imaging sensors for precision agriculture

Chenghai YANG

《农业科学与工程前沿（英文）》 2018年第5卷第4期页码 393-405 doi: 10.15302/J-FASE-2018226

摘要：

The central concept of precision agriculture is to manage within-field soil and crop growth variability for more efficient use of farming inputs. Remote sensing has been an integral part of precision agriculture since the farming technology started developing in the mid to late 1980s. Various types of remote sensors carried on ground-based platforms, manned aircraft, satellites, and more recently, unmanned aircraft have been used for precision agriculture applications. Original satellite sensors, such as Landsat and SPOT, have commonly been used for agricultural applications over large geographic areas since the 1970s, but they have limited use for precision agriculture because of their relatively coarse spatial resolution and long revisit time. Recent developments in high resolution satellite sensors have significantly narrowed the gap in spatial resolution between satellite imagery and airborne imagery. Since the first high resolution satellite sensor IKONOS was launched in 1999, numerous commercial high resolution satellite sensors have become available. These imaging sensors not only provide images with high spatial resolution, but can also repeatedly view the same target area. The high revisit frequency and fast data turnaround time, combined with their relatively large aerial coverage, make high resolution satellite sensors attractive for many applications, including precision agriculture. This article will provide an overview of commercially available high resolution satellite sensors that have been used or have potential for precision agriculture. The applications of these sensors for precision agriculture are reviewed and application examples based on the studies conducted by the author and his collaborators are provided to illustrate how high resolution satellite imagery has been used for crop identification, crop yield variability mapping and pest management. Some challenges and future directions on the use of high resolution satellite sensors and other types of remote sensors for precision agriculture are discussed.

关键词： high resolution satellite sensor multispectral imagery precision agriculture spatial resolution temporal resolution