Heavy metal concentrations of agricultural soils and vegetables from Dongguan, Guangdong

A total of 118 of agricultural soil and 43 of vegetable samples were collected from Dongguan City, Guangdong, China. The spatial distribution, sources, accumulation characteristics and potential risk of heavy metals in the agricultural soils and vegetables were depicted in details by three different approaches, including total contents of eight metal elements in soils and vegetables, GIS maps and multivariate analysis of heavy metals in soils in the study. The results show that there are higher accumulation of heavy metals such as Cu, Zn, Ni, Pb, Cd and Hg in agricultural soils, and the contents of Pb （65.38 mg kg^-1） and Hg （0.24 mg kg^-1） are 1.82 and 2.82 times of the background contents of the corresponding heavy metals in soils of Guangdong Province, respectively. There are about 3.4% of Cu, 5.9% of Ni, 1.7% of Cd and 28% of Hg in all collected soil samples from all investigated sites which have overran the contents for heavy metals of the China Environmental Quality Standard for Soils （GB15618-1995, Grade Ⅱ）. The pollution characteristics of multi-metals in soils are mainly reflected by Hg. There are different sources to eight metal elements in soils, Cu, Zn, Ni Cr and As are predominantly derived from parent materials, and Pb, Hg and Cd are affected by anthropogenic activities. The spatial distribution shows that the Cu, Zn, Ni, Cr, Pb, As and Hg contents of agricultural soils are high in the west and low in the east, and Cd contents are high in the northwest, southeast and low in the southwest in Dongguan. The ratios of vegetable samples which Ni, Pb and As concentrations higher than the Maximum Levels of Contaminants in Foods （GB2762-2005） are 4.7%, 16.3% and 48.8%, respectively. The order of bio-concentration factors （BCF） of heavy metals in vegetables is Cd 〉 Zn 〉 Cu 〉 As 〉 Ni 〉 Hg 〉 Cr 〉 Pb. It is necessary to focus on potential risk of heavy metals for food safety and human＇s health from agricultural soils and vegetables in Dongguan City, Guangdong Province.

Spatial distribution of heavy metals of agricultural soils in Dongguan, China

Distribution and speciation of heavy metals of agricultural soils(85 surface soil samples and 4 soil profiles) in Dongguan were investigated, while total Cr, Cu, Ni, Pb, Zn(abbreviated as Cr, Cu, Ni, Pb, Zn) and available Cu, Zn(Av-Cu, Av-Zn) were analyzed by a flame absorption spectrophotometer(AAS), and total Cd(Cd) was analyzed using graphite furnace AAS. The content of Cd, Cu and Ni was partially much more than the second grade of GB15618-1995 even though the mean contents of all heavy metal were less than the threshold value of the second grade and only the mean content of Pb was more than the value of national background. Results of descriptive statistic showed that the mean content of heavy metals should depend on land utilization and spatial location at some extent. The heavy metal contents were higher in the Southwest and Northwest than in the Central. In addition, the mean contents of Zn and Pb in Dongguan paddy soils were significantly higher than those of Pearl River Delta(PRD) and Taihu Lake region(TLR). Correlation analyses indicated that there existed significant correlation between Cr and Ni in orchard soils, and among Zn, Cd and Cu, between Av-Cu and Cu, between Av-Zn and Cr, Ni, pH value in vegetable soils, and a weak relationship between Cd, Cu and Pb, between Av-Zn and Zn. Principal component analyses(PCA) showed that the order of importance should be Zn>Pb>Cr>Ni>Cu.

CHARACTERISTICS OF BOUNDARY LAYER AND ITS EFFECTS ON ATMOSPHERIC AEROSOL CONCENTRATIONS IN DONGGUAN, GUANGDONG

The structure of atmospheric boundary layer determines the ability of atmospheric dispersion and has an essential impact on airborne aerosols.In this paper,the data of a radio sounding experiment held in Dongguan National Meteorological Observation Station,which is in a coastal city in Pearl River Delta,as well as the data of atmospheric aerosols,were utilized in order to analyze the characteristics of atmospheric boundary layer and its effects on surface aerosol concentrations.The results are showed at follows:the local circulations,associated with dominant winds,made complex structures of atmospheric layers,as the cold air and systematic winds weakened in the end of a cold air event.Weakened wind shears and inversion layers,especially a strong near-surface inversion layer,remarkably diminished the atmospheric diffusion abilities and facilitated an especially high concentration of surface aerosols.The convergence line or weak shear line of sea breeze in the ground level helps weaken the atmospheric diffusion abilities and results in atmospheric aerosols accumulation.

AHP-based System for the Health Assessment of Ancient and Famous Trees in Dongguan

By establishing an AHP-based assessment index system and assessment model,and applying detection technology that is convenient and harmless for ancient and famous trees,this paper is significant for investigating and assessing the health state of ancient and famous trees,and protecting the limited resources. Fourteen indexes such as growth vigor,disease and pest were selected from the perspectives of overall situation,canopy,trunk and root,and AHP(applied analytic hierarchy process) was applied to define weights of these indexes. According to the results,top 3 indexes in terms of weight are tree vigor,treetop death,internal decay and hole,while the indexes with lower weight are parasitism,root damage,ventilation and permeability. On the basis of assessment model and method as well as field investigation,health grade of ancient and famous trees(A) can be obtained. By grading the health of ancient and famous trees into 3 levels,each level indicates a certain health state,so managers can take corresponding maintenance measures to develop the best ecological and social value of these trees.

Protection and Development of Dongguan Historical and Cultural Block in Yangzhou

Dongguan Street in Yangzhou is a block composed of ancient buildings left over from theMing and Qing Dynasties.Three major gardens in Yangzhou,Ge Garden,Ho Family Garden and XieGarden,are located in the block.Due to the proximity to Dongguan ancient ferry,a large number ofgardens gathered forming the famous Dongguan Street in the Ming and Qing Dynasties.The protectionand restoration of Dongguan Street should focus on not only the preservation and restoration of historicalrelics,but also the maintenance and renewal of traditional cultural environment,to make the new functionsand vitality adapt to its characteristics.Moreover,historical towns and blocks will maintain harmonious andunifi ed development,and adapt to the sustainable development of Yangzhou City.

Two IT Fairs Simultaneously Held in Dongguan

In the two fairs, the most advanced world level techonologies and products, including computers, electronics parts, individual infor-mation products were shown on 700-more exhibition sites.

The Way for the Integrated Establishment of Public Service Platform in Grassroots Community and Guarantee Measures——Case Study of Dongguan

This paper takes the public services in the grassroots community of Dongguan as the object of study and studies the integrated construction of the public service platform in grassroots communities with the thinking principle of resources integration so as to set up a service platform integrating electronization, informatization and networking, ensure the convenience of public services and provide high-quality community public services for the community residents.

Evolution of Industrial Competitiveness Based on Evaluation of Urban Competitiveness of Dongguan City:A Case Study of Songshan Lake High-tech Zone

Based on the theoretical system of urban competitiveness,the evaluation model of urban competitiveness from the perspective of competition and cooperation was established.According to the significance index and explanatory index,the urban competitiveness was divided into urban comprehensive competitiveness(UC),urban internal node competitiveness(NC)and external competitiveness of urban network(EC).The scores and rankings of UC,NC and EC in 2006,2010 and 2015 were obtained by conducting the comprehensive evaluation of the urban competitiveness of Dongguan City with integrated usage of the principal component analysis and Technique for Order Preference by Similarity to an Ideal Solution and the data of other 20 cities in Guangdong province,Hong Kong and Macao.The research showed that the competitiveness of Dongguan City has been greatly improved during the decade of 2006–2015,and the regional cities in Guangdong Province had significant differences,which are reflected in the two dimensions of urban internal node competitiveness(NC)and external competitiveness of urban network(EC).Based on this,this study further analyzed Dongguan’s urban competitiveness from two dimensions of NC and EC,and took Dongguan Songshan Lake High-tech Zone as an example to study how to promote Dongguan’s urban competitiveness from the industrial level.

On Innovation of Coordinative Development Mechanism of Science and Technology Park with Surrounding Areas under Promotion of the Government——Case Study on Three Science and Technology Park in Dongguan

Science and Technology Park, which plays a very important role in promoting rapid development of regional economy, has enjoyed various preferential policies in its unique development since China’s reform and opening up, which oppositely shows that the government has overlooked development outside the park and resulted in negative competition between the science and technology park and surrounding areas in resources and industry development, etc. Therefore, it is necessary and urgent to overcome the existing obstacles against coordinative development between the park and surrounding areas, to explore paths where the two can development coordinately and to achieve new breakthrough and innovation in coordinative development in subject, object, platform and mechanism.

Urban Growth Modeling Using Neural Network Simulation: A Case Study of Dongguan City, China

Dongguan is an important industrial city, located in the Pearl River Delta, South China. Recently, Dongguan city experienced a rapid urban growth with the locational advantage by transforming from traditional agricultural region to modern manufacturing metropolis. The urban transformation became the usual change in China under the background of urbanization which belongs to one trend of globalization in the 21st century. This paper tries to analyze urban growth simulation based on remotely sensed data of previous years and the related physical and socio-economic factors and predict future urban growth in 2024. The study examined and compared the land use/cover (LUC) changes over time based on produced maps of 2004, 2009, and 2014. The results showed that water and forest area decreased since the past years. In contrast, the urban land increased from 2004 to 2014, and this increasing trend will continue to the future years through the urbanization process. Having understood the spatiotemporal trends of urban growth, the study simulated the urban growth of Dongguan city for 2024 using neural network simulation technique. Further, the figure of merit (FoM) of simulated map of 2014 map was 8.86%, which can be accepted in the simulation and used in the prediction process. Based on the consideration of water body and forest, the newly growth area is located in the west, northeast, and southeast regions of Dongguan city. The finding can help us to understand which areas are going to be considered in the future urban planning and policy by the local government.

In search of service innovations by public libraries in Chinese urban centers:A case study of Dongguan Library

This article introduces several of the more significant service delivery innovations and their resulting accomplishments instigated by Dongguan Library(thereafter abbreviated as DGL) in recent years. The textual exposition of this paper is based on a case study of DGL by this author about its user-centered vision, mission, immediate objectives and the exhibited service performance within a contextual environment of collegial support from its professional peers. After a five-year period of intensive efforts on such focused professional development and practice, DGL has completed its information service mapping and information delivery for the entire municipality of Dongguan on a 7-day and twentyfour-hour(7/24) basis. This singular feast of accomplishment seems to suggest the moral that any significant development of scale of a municipal library has to be in keeping pace closely with the progress of the society at large in general and with the changing information demands of its local clientele in particular.

Restructuring of Industrial Talents and Their Characteristics from the Perspective of Intelligent Manufacturing in Dongguan

The advancement of intelligent manufacturing in Dongguan puts forward new requirements for industrial talents,and the development of new productivity is bound to force enterprises and employees to make adaptive adjustments.The upgrading of intelligent manufacturing is not only the upgrading of intelligent machines but also the upgrading of the human brain,which includes the reshaping and cultivation of industrial talents.Based on field research,this study analyzes the different characteristics of the traditional and the new intelligent manufacturing model,as well as summarizes the characteristics of industrial talents and the changing trend of talent demand in view of the intelligent manufacturing model in Dongguan.

PRINT CHINA 2007——No.1 printing exhibition in China in 2007 meets you at Dongguan city in spring time

The first International Printing Technology Exhibition of China（Guangdong）is held from 10th-14thApril 2007.The abbreviation of the name of this exhibition is PRINT CHINA. The first PRINT CHINA attracts not only large quantity of printing and packaging equipment and material suppliers home and abroad to participate in the show,but also enormous num- bers of domestic and overseas visitors to attend the show.

ANALYSIS OF LONG TERM CHARACTERISTICS OF INTERANNUAL CHANGE OF TEMPERATURE IN DONGGUAN OVER THE RECENT 50 YEARS

With the series of annual and seasonal temperature during 1957 – 2001 in Dongguan, Guangdong, the statistical characteristic and power spectrum and secular trend and sudden change phenomena are computed in this paper. From the results it is known that (1) the temperatures have obvious characteristics of monsoon climate but do not have normal distribution, showing biased distribution of high or low kurtosis; (2) over the recent half- century, the temperatures tend to rise, specially in the last 10 years, in which mean temperature have quickly ascended by about 1.5°C, and except for the spring, there were sudden change of seasonal temperature rising from the 1980’s to 1990’s, which really reflected the influence of developing and opening and urbanization on Dongguan temperature; (3) except for the spring, the temperature of other seasons show some oscillatory periods in Dongguan and some of them also include long-term variation trends.

广东省东莞市国土空间生态安全格局构建与分析

构建国土空间生态安全格局可以约束和引导城市空间发展,实现城市发展与区域环境协调可持续发展。本研究通过遥感生态指数、最小累计阻力模型等方法,识别广东省东莞市生态安全格局的生态源地、生态廊道、生态夹点及生态障碍点等要素,提出相关优化建议。结果表明:①全市生态基底好,生态空间连片,生态廊道分布均匀且能够有效串联生态源地;②滨水空间保护提升和道路绿化建设为生态要素流动提供有效路径;③农业生产、交通运输对生态网络影响最强烈,其次是工业生产和居民生活;④应将生态源地、12 m宽生态廊道和生态夹点划为生态保护重点区,将200 m宽生态廊道和生态障碍点划为生态修复重点区。本研究可为东莞市构建国土空间生态安全格局提供科学依据。

系统化全域推进海绵城市建设实施方案编制思考——以东莞市为例

自2012年起,国家倡导各地以海绵城市建设试点为契机,打造宜居、绿色、韧性、智慧、人文城市,经过10余年的发展,建设海绵城市已成为重要的城市发展理念。在全新的系统化全域海绵城市建设背景下,以东莞市为例,以全域生态红线、城市蓝线、城市绿线、蓄滞洪区等重要的生态蓝绿空间管控为基础,构建连续完整的全域生态基础设施体系。在此基础上,为进一步突出示范特色,选取中心城区、松山湖高新区、谢岗镇作为重点示范建设区域(相关流域范围一并纳入),分别从老城区、新城区、小城镇3种不同区域,探索总结系统化全域推进海绵城市建设的经验做法,拟为类似城市开展相关研究提供借鉴与参考。

Comparison between CBR and CA methods for estimating land use change in Dongguan, China

Many studies on land use change （LUC）, using different approaches and models, have yielded good results. Applications of these methods have revealed both advantages and limitations. However, LUC is a complex problem due to influences of many factors, and variations in policy and natural conditions. Hence, the characteristics and regional suitability of different methods require further research, and comparison of typical approaches is required. Since the late 1980s, CA has been used to simulate urban growth, urban sprawl and land use evolution successfully. Nowadays it is very popular in resolving the LUC estimating problem. Casebased reasoning （CBR）, as an artificial intelligence technology, has also been employed to study LUC by some researchers since the 2000s. More and more researchers used the CBR method in the study of LUC. The CA approach is a mathematical system constructed from many typical simple components, which together are capable of simulating complex behavior, while CBR is a problem-oriented analysis method to solve geographic problems, particularly when the driving mechanisms of geographic processes are not yet understood fully. These two methods were completely different in the LUC research. Thus, in this paper, based on the enhanced CBR model, which is proposed in our previous research （Duet aL 2009）, a comparison between the CBR and CA approaches to assessing LUC is presented. LUC in Dongguan coastal region, China is investigated. Applications of the improved CBR and the cellular automata （CA） to the study area, produce results demonstrating a similarity estimation accuracy of 89% from the improved CBR, and 70.7% accuracy from the CA. From the results, we can see that the accuracies of the CA and CBR approaches are both 〉70%. Although CA method has the distinct advantage in predicting the urban type, CBR method has the obvious tendency in predicting non-urban type. Considering the entire analytical process, the preprocessing workload in CBR is less than that of the CA approach. As such, it could be concluded that the CBR approach is more flexible and practically useful than the CA approach for estimating land use change.

青年发展型城市的空间响应与规划策略——以东莞为例

从目前已有的理论研究和实践来看,青年发展型城市的探索仍然偏向工作方案和政策层面,针对空间需求及规划建设策略的研究相对较少。基于需求理论、空间干预理论,探讨青年发展型城市中“青年成长—城市发展”相互作用、双向奔赴的内涵,提出保障型、融合型、发展型、互促型4类青年发展空间。根据青年人群结构、城市发展阶段的不同,这4类空间的空间要素、空间布局、供给模式、建设指引呈现不同的特点,并以东莞这一“青春之城”为例,从4类空间出发,提出青年发展导向的空间规划策略。

《东莞植物志》新资料

[目的]探明东莞市大岭山森林公园的植物资源,为该区域的植物资源保护及可持续利用提供资料。[方法]通过查阅文献资料、专家咨询与野外实地调查相结合的方法对大岭山森林公园的植物多样性进行全面调查。[结果]发现了《东莞植物志》未收录的12个植物物种,分别是虎克鳞盖蕨(Microlepia hookeriana)、稀羽鳞毛蕨(Dryopteris sparsa)、绒毛山胡椒(Lindera nacusua)、黄毛五月茶(Antidesma fordii)、柴胡叶链荚豆(Alysicarpus bupleurifolius)、一年蓬(Erigeron annuus)、车前(Plantago asiatica)、地旋花(Xenostegia tridentata)、钳唇兰(Erythrodes blumei)、宽叶线柱兰(Zeuxine affinis)、苏里南莎草(Cyperus surinamensis)、三俭草(Rhynchospora corymbosa)。[结论]新发现的植物种类丰富了东莞市的植物资源资料,对植物物种多样性和植物区系的研究具有重要意义。

基于信息量-支持向量机组合模型的东莞市地面沉降灾害易发性评价

易发性评价是地面沉降灾害风险识别及减避控制的靶向关键技术问题,为解决单一评价模型存在的过拟合问题,以东莞市地面沉降发育重点区为对象,采用相关系数法筛选并构建由软土层厚度、填土层厚度、与断裂带距离、建筑密度和道路密度组成的评价因子组合,开展基于信息量-支持向量机组合模型的地面沉降易发性评价,并结合地理信息系统(GIS)划分出高(Ⅰ)、中(Ⅱ)和低(Ⅲ)3个易发性等级分区。结果表明:使用受试者工作特征曲线(ROC)和历史灾点验证法校验,信息量-支持向量机(IM-SVM)组合模型的AUC值为0.915,位于高、中易发性分区内的灾点数为90.57%,较单一信息量模型(IM)和支持向量机模型(SVM)具有更高的评价精度。基于数据驱动的机器学习法在对灾害评价分类方面有更强的优越性,进一步选取相同原理、性能差异不大的学习器进行组合更能实现评价可靠性的提高。