Spatial Agglomeration of Exhibition Enterprises on a Regional Scale in China

During the past two decades, the exhibition industry in China has been developing rapidly and has become an important part of the modern service industry, particularly the agglomeration characteristics of exhibition enterprises highlighted on the regional scale. Although the development of theoretical research on the western exhibition industry has taken place over time, the spatial perspective has not been at the centre of attention so far. This paper aims to fill this gap and report on the agglomeration characteristics of exhibition enterprises and their influential factors. Based on data about exhibition enterprises in the Pearl River Delta(PRD) during 1991–2013, using the Ripley K function analysis and kernel density estimation, this research identifies that: 1) the exhibition enterprise on the regional scale is significantly characterized by spatial agglomeration, and the agglomeration density and scale are continuously increasing; 2) the spatial pattern of agglomeration has developed from a single-center to multi-center form. Meanwhile, this paper profiles the factors influencing the spatial agglomeration of exhibition enterprises by selecting the panel data of nine cities in the PRD in 1999, 2002, 2006 and 2013. The results show that market capacity, urban informatization level and exhibition venues significantly influence the location choice of exhibition enterprises. Among them, the market capacity is a variable that exerts a far greater impact than other factors do.

Quantitative method for calculating spatial release region for laser-guided bomb

The laser-guided bomb(LGB)is an air-to-ground pre-cision-guided weapon that offers high hit rates,great power,and ease of use.LGBs are guided by semi-active laser ground-seek-ing technology,which means that atmospheric conditions can affect their accuracy.The spatial release region(SRR)of LGBs is difficult to calculate precisely,especially when there is a poor field of view.This can result in a lower real hit probability.To increase the hit probability of LGBs in tough atmospheric situa-tions,a novel method for calculating the SRR has been pro-posed.This method is based on the transmittance model of the 1.06μm laser in atmospheric species and the laser diffuse reflection model of the target surface to determine the capture target time of the laser seeker.Then,it calculates the boundary ballistic space starting position by ballistic model and gets the spatial scope of the spatial release region.This method can determine the release region of LGBs based on flight test data such as instantaneous velocity,altitude,off-axis angle,and atmospheric visibility.By more effectively employing aircraft release conditions,atmospheric visibility and other factors,the SRR calculation method can improve LGB hit probabi-lity by 9.2%.

Quantitative Analysis of the Outdoor Thermal Comfort in the Hot and Humid Summertime of Shenzhen, China

Outdoor thermal comfort has always been a major issue due to its irreplaceable role in maintaining good health and energy use. Thus,quantitative analysis of outdoor thermal comfort and discussions on influential factors seem very necessary to achieve the climate-conscious urban design. Therefore,an outdoor thermal comfort questionnaire survey and the simultaneous field measurement were conducted in six different places during the hot and humid summertime in Shenzhen. The results show that the overall weather conditions during the investigation can be expressed with high temperature and high humidity with strong solar radiation. The micro-meteorological parameters of six test sites vary greatly due to their different regional spatial layouts.Moderate range of air temperature( Ta) is between 28 to 30 ℃ while that of relative humidity( RH) mainly concentrates in 60%-70% with the thermal sensation votes. The main influential factors impacting outdoor thermal comfort are obtained and Tahas the greatest effect. The overall thermal comfortable ranges in Shenzhen are expressed by the range of 28. 14-32. 83 ℃ of PET and 24. 74-30. 45 ℃ of SET*. With the correlation analysis between the characteristic parameters of regional spatial layout and thermal climate and thermal comfort,it reveals that increasing the coverage ratio of water and green space( S) helps lower Taand increase RH. The global solar radiation( G) has a significant negative correlation with the height of buildings( H) and a positive correlation with sky view factor( SVF). Overall,reasonable configuration of the regional spatial layout contributes to providing a thermal comfortable environment.

Spatial distribution, seasonal variation and regionalization of PM_(2.5) concentrations in China

In order to provide scientific support to policy makers in the regulation of PM2.5 pollution in China, it is important to accurately assess the current status, spatiotemporal characteristics and regionalization data for this air pollutant. An analysis of the pollution status of PM2.5 was conducted using daily averaged mass concentration data recorded in 74 cities in 2013 and 161 cities in 2014. The rotated empirical orthogonal function(REOF) method was applied to analyze this data. Results showed that the average annual PM2.5 concentration in urban areas of China is 62.2±21.5 ?g/m3, and that the distribution is spatially heterogeneous. The North China Plain, middle and lower Yangtze River Plain, Sichuan Basin and Guanzhong Plain had relatively high annual PM2.5 concentrations compared with the southeast coastal region, the Tibetan Plateau and the Yungui Plateau. PM2.5 mass concentrations tended to be higher in winter than in summer, however, the data for many cities showed a small peak in concentrations from May to July. An analysis of the spatial correlation of PM2.5 indicated a significant influence of topographic conditions. A lower correlation was observed where terrain features varied greatly. Based on the results of the REOF analysis and topographic characteristics, ten regions were identified in mid-eastern China, which could be considered as basic pollution prevention divisions for PM2.5; these include the North China Plain region, Pearl River Delta region, Jianghuai Plain region, middle Yangtze River Plain region, Northeast Plain region, Jiangnan coastal region, Sichuan Basin region, Qiantao Plain region, Guanzhong-Central Plain region and Yungui Plateau region. Seasonal variations in the regionalization data were observed, especially for the North China Plain and Pearl River Delta regions. Among the ten regions identified in this study, the North China Plain, Guanzhong-Central Plain, middle Yangtze River Plain and Jianghuai Plain had relatively high PM2.5 mass concentrations in comparison with the others. Therefore, these regions should be considered as the key regions to target in developing PM2.5 pollution prevention strategies. This study improves the present understanding of the spatial distribution, seasonal changes and regional status of PM2.5 pollution in China and helps establish possible control strategies for the reduction of this air pollutant.

Spatial function regionalization and governance of coastal zone: A case study in Ningbo City

Reasonable development and utilization of spatial resources in the coastal zone not only affects the development quality of the marine economy but also impacts the utilization efficiency of spatial resources,playing an important role in regional sustainable development.Depending on the natural,economic,and societal characteristics of a region,research topics such as using relevant methods to divide the coastline,proper spatial development of the coast,protecting coastal zones,and achieving higher spatial resource distribution efficiency have recently become hot topics in geographic research.Most of the scholars construct the evaluation index system from the perspective of economic and ecological factors and undertake some exploration of the division methods.However,the selection of indicators for a coastal zone needs a different and more scientific approach.There is a need for emphasizing the overall strategy of land-ocean integration in developing spatial resources in a coastal zone.Taking the coastal zone in Ningbo as an example,this paper develops a new evaluation framework and spatial function regionalization method that is used to divide the coastline and coastal zone.Based on the perspective of overall strategy for the land and ocean,we evaluate the suitability of coastline development.We then propose the spatial function regionalization of the coastal zone.Finally,based on the status quo of spatial development in Ningbo,we divide the coastal zone into ecological space,production space and living space,and propose adjustment directions and control requirements for the different types of spatial layouts.

Topological relations between spherical spatial regions with holes

There is growing interest in globally modelling the entire planet.Although topological relations between spherical simple regions and topological relations between regions with holes in the plane have been investigated,few studies have focused on the topological relations between spherical spatial regions with holes.The 16-intersection model(16IM)is proposed to describe the topological relations between spatial regions with holes.A total of 25 negative conditions are proposed to eliminate the impossible topological relations between spherical spatial regions with holes.The results show that(1)3 disjoint relations,3 meet relations,66 overlap relations,7 cover relations,3 contain relations,1 equal relation,7 coveredBy relations,3 inside relations,1 attach relation,52 entwined relations,and 28 embrace relations can be distinguished by the 16IM and that(2)the formalisms of attach,entwined,and embrace relations between the spherical spatial regions without holes based on the 9IM and that between the spherical spatial regions with holes based on the simplified 16IM are different,whereas the formalisms of other types of relations between spherical spatial regions without holes based on the 9IM and that between the spherical spatial regions with holes based on a simplified 16IM are the same.

SIMULATION OF THE SPATIAL DISTRIBUTION OF CLIMATIC ELEMENTS IN MOUNTAINOUS REGIONS

In this paper,an effective method of simulating the spatial distribution of climatic elements in mountainous areas by using the semi-empirical theory is presented.As an example,the spatial distributions of temperature, vapor pressure,relative humidity,wind speed and precipitation in the Jianyang region and the Shaxi basin of Fujian Province are computed with this method,and the simulated results are in good agreement with the observations.

Chaos bound in Kerr-Newman-Taub-NUT black holes via circular motions

In this study,we investigate the influence of the angular momentum of a charged particle around Kerr-Newman-Taub-NUT black holes on the Lyapunov exponent and find spatial regions where the chaos bound is violated.The exponent is obtained by solving the determination of the eigenvalues of a Jacobian matrix in the phase space.Equilibrium positions are obtained by fixing the charge-to-mass ratio of the particle and changing its angular momentum.For certain values of the black holes’electric charge,the NUT charge and rotational parameter,a small angular momentum of the particle,even with zero angular momentum,causes violation of the bound.This violation disappears at a certain distance from the event horizon of the non-extremal Kerr-Newman-Taub-NUT black hole when the angular momentum increases to a certain value.When the black hole is extremal,the violation always exists no matter how the angular momentum changes.The ranges of the angular momentum and spatial regions for the violation are found.The black holes and particle rotating in the same and opposite directions are discussed.