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Current Issue
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Study on stability of systems with forced term
- GUO Laigang, CHEN Yufu
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2017, 34 (3):
277-288.
DOI: 10.7523/j.issn.2095-6134.2017.03.002
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Abstract (
246 )
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In this work, the system with forced term is considered. Two methods for adding the forced term to the differential dynamical systems for asymptotic stability are given. The first method is based on Lyapunov's direct method, and the second method is a new method based on stability analysis of Hopf bifurcations. The new method has a discriminant which is a rational expression consisting of the coefficients in the original system. Some further researches for adding forced term are also presented.
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Influence of Zeeman magnetic field on the nodal structure of unconventional superconductors
- CHEN Chongju, JIN Biao
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2017, 34 (3):
289-295.
DOI: 10.7523/j.issn.2095-6134.2017.03.003
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Abstract (
247 )
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In most of the unconventional superconductors, the quasiparticle excitation spectrum possesses line or point nodes leading to a power-law temperature dependence in the thermodynamic quantities and transport coefficients at low temperatures. In this work we show analytically that an applied weak Zeeman magnetic field can drastically alter these nodal structures. In particular, we predict that surface nodes might be induced on the Fermi surface under certain circumstances. Our numerical calculations of electronic specific heat for selected spin-singlet and spin-triplet states confirm that the change in the nodal structure may accompany significant modification in the power-law temperature dependence.
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Application potentiality and prospects of nighttime light remote sensing in "the Belt and Road" initiative
- JIANG Wei, HE Guojin, PENG Yan, WANG Guizhou, WANG Mengmeng
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2017, 34 (3):
296-303.
DOI: 10.7523/j.issn.2095-6134.2017.03.004
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Abstract (
549 )
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"The Belt and Road" initiatives, with its wide range, diverse cultures, and vulnerable ecological environments, needs the earth observation technology to deal with various new challenges. In this work, firstly the geographical scientific connotation of "the Belt and Road" initiatives was analyzed, and then the capability of nighttime light remote sensing was explored and the application areas of this technology in "the Belt and Road" initiatives construction were summarized. Furthermore, the advantages of nighttime light remote sensing in earth observation technology were reviewed. In order to meet the requirements of the countries along the belt and road, four nighttime light remote sensing application areas, i.e., the gas fire spatiotemporal information mining, social economic parameter estimation, ecological environment evaluation, and reconstruction of the urbanization process, were put forward in this work. The implementation of these applications will effectively support the decision making for the countries along the belt and road.
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Correlation of fuel quality and emissions of motor vehicle with atmospheric pollution in Beijing
- YANG Kunhao, XIA Zanyu, HE Peng, WU Li, GONG Lingling, QIAN Yueying, HOU Yanlin, HE Yujian
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2017, 34 (3):
304-317.
DOI: 10.7523/j.issn.2095-6134.2017.03.005
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Abstract (
252 )
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In order to clarify the real origin of the atmospheric pollution in Beijing， the correlation of fuel quality and emission of motor vehicle with atmospheric pollution in Beijing was studied in this work.The qualities of various major brands of fuel were analyzed by using the methods of instrumental analysis such as GC-MS. A new idea that the average daily change of the contaminant in unit volume is considered as reference standard in calculation of the contribution rates of various pollutants below the inversion layer in static stability weather is set up. Firstly， the average daily emissions of the main pollutants including CO，HC，NO2, and SO2 in unit volume were studied.Next the real measured daily variation of the pollutants in unit volume from November 2013 to October 2015 was studied.Then the contribution rates of the various pollutants by the vehicle exhausting to the respective atmospheric pollutants were calculated.The results are showed as follows. 1) The heavy metal contents， sulfur content, and aromatic hydrocarbon contents exceeded the limits. The nitrogen content was high, but there is no limit in international standard. 2) In heating season，the contribution rates of CO， NO2, and SO2 by the vehicle exhausting to the corresponding atmospheric pollutants were 30.1%， 72.4%, and 6.6%, respectively, and in no-heating season，the contribution rates were 53.3%，74.3%, and 20.3%, respectively. The annual average sharing percentage of the motor vehicle HC emission was about 67.8%. Based on the results of this study，fuel combustion is the major cause of air pollution in Beijing， and several specific advices and measures for effectively controlling the atmospheric pollution in Beijing are put forward.
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Influence mechanism of coal mining subsidence on soil quality and restoration measures in west China aeolian sand area
- SHI Peili, ZHANG Yuxiu, HU Zhenqi, MA Kang, YU Bingbing
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2017, 34 (3):
318-328.
DOI: 10.7523/j.issn.2095-6134.2017.03.006
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Abstract (
209 )
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The ecological environment is fragile in west China aeolian sand area. Large-scale underground coal mining causes soil collapse and ground fissures， which lead to a series of ecological and environmental problem such as groundwater level fall, serious loss of soil moisture and nutrient, decrease in soil enzyme activities, reduction in soil microbial communities and population, soil sandy desertification, vegetation damage, and destruction of biological diversity. This work analyzes the influence mechanism of underground coal mining on soil chemical and physical properties, vegetation, and soil microorganism, and proposes the corresponding restoration measures of destructive soil environment in west China aeolian sand area. In addition, this work suggests that the future research should focus on the restoration of soil quality and the successional law of soil microbial diversity. These findings would provide theoretic foundations and technical supports for supervising land reclamation and ecological constructions in coal mining subsidence area.
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Multi-scale spatial distributions of Oedaleus decorus asiaticus
- LI Yao, ZHANG Na
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2017, 34 (3):
329-341.
DOI: 10.7523/j.issn.2095-6134.2017.03.007
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Abstract (
313 )
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This study discusses the spatial distributions of Oedaleus decorus asiaticus (O.d. asiaticus) and the habitat factors which are responsible for the spatial distributions of O. d. asiaticus at different scales. Using the field survey data of O. d. asiaticus density and habitat conditions in Aobaoyingaole village, Xianghuangqi County of Xilingol League, Inner Mongolia, China, we obtained the spatial distribution of grasshopper habitat suitability value (S) within the study area. Then we carried out the spatial autocorrelation analysis of Moran's I, scale variance analysis coupled with Moran's I scalogram, wavelet analysis, or lacunarity analysis to detect the spatial patterns of S value and other related habitat variables. The results showed that O. d. asiaticus exhibited patchy distributions within the three scale domains: <0.3 km, <0.7~1.0 km, and <1.9 km, which might result from the combined effects of many habitat factors at different scales. Vegetation type and vegetation coverage were responsible for the distributions of grasshopper individuals within all the three scale domains; slope, aspect, and topographic wetness index were responsible for the distributions within the moderate and small scale domains; elevation was responsible for the distributions within the large and moderate scale domains; and soil sand content, soil pH value, soil organic matter content, and leaf nitrogen content were responsible for the distribution within the moderate scale domain.
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Spatial-temporal coupling characteristics between population structure and economic development in Northeast China
- XIONG Lin, ZHANG Pingyu, TAN Juntao, LIU Wenxin
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2017, 34 (3):
342-350.
DOI: 10.7523/j.issn.2095-6134.2017.03.008
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Abstract (
274 )
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The population problem has become a focus for revitalizing the old industrial base in Northeast China. Utilizing the gray relative analysis method (GRA) and building quantitative assessment models, we study the spatial-temporal coupling characteristics between population structure and economic development in Northeast China. Research results are given as follows. In the spatial sequence, there are clear differences in the coupling degree between population structure and economic development among the cities. In terms of the coupling characteristics and the coupling degree value, the 36 cities are classified into four types, namely, low-level，antagonism, running-in, and high-level types. The major type is the antagonism, followed by running-in type. In the temporal sequence, there are two significant periods. From 2004 to 2009 the coupling degree rose with fluctuat, and from 2010 to 2013 the coupling degree fell down quickly. According to the spatial-temporal coupling characteristics, countermeasures such as optimizing and upgrading the industrial structure, attracting talents, cultivating talents, and retaining talents enhance the coordinated developments of population and economy, and promote the revitalization of Northeast China.
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Spatial pattern and mechanisms of basic public services in Sichuan
- CAO Sha, LIU Shaoquan, PENG Li, XU Dingde
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2017, 34 (3):
351-361.
DOI: 10.7523/j.issn.2095-6134.2017.03.009
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Abstract (
230 )
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On the basis of the comprehensive measurements of the levels of basic public services of all the cities in Sichuan by using the projection pursuit model, we analyze the spatial pattern of the level and development difference of basic public services and the driving mechanisms of the spatial pattern in Sichuan. This study indicates that although the developments of some cities are undulate, the overall trend of the level of basic public services in the cities in Sichuan is going up, and Chengdu and Panzhihua have always been on the top of the level list. From the perspective of spatial pattern, the levels of basic public services in the areas along Baoji-Chengdu and Chengdu-Kunming railway lines are significantly higher than in the other regions. The levels in the eastern areas are generally higher than in the western areas. The development tendency of the levels of basic public services among all the cities in Sichuan is balanced, and it does not show significant "Matthew effect". Driving mechanism analysis shows that the policies and government action on the development of basic public services have the function of macro guidance; the economic and social development is the main driving force; and the restrictive effect of the natural and geographical conditions is weakening with the development of society and economy.
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Spatial differentiation characteristics and impact factors of poverty settlements in Lanzhou City
- ZHANG Xinhong
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2017, 34 (3):
362-370.
DOI: 10.7523/j.issn.2095-6134.2017.03.010
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Abstract (
217 )
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Based on the spatial and social characteristics, we classified the 155 poverty settlements in Lanzhou City into shanty-town type, urban-village type, multi-ethnic type, and single-Han-ethnic type. Then, we analyzed the spatial differentiation characteristics of poverty settlements and the impact factors using several methods such as nearest neighbor index (NNI), kernel density, buffer analysis, and overlay analysis. The results are given as follows. 1) The poverty settlements of shanty-town type, urban-village type, and single-Han-ethnic type present condensed distributions, but the multi-ethnic type presents dispersed distribution. 2) There are a high density area and a second high density area for each of the four types. There is also a third density area for each of single-Han-ethnic type and multi-ethnic type, but the central locations and the highest density values are different. 3) In terms of the spatial relations between poverty settlements and the three basic geographical elements which are the Yellow River, drainage ditches, and railways, the numbers and proportions of the four types of poverty settlements are different, and the difference of close-distant relationship is large. 4) The spatial differentiation of poverty settlements is a synergic result of several factors. At microscopic level, the natural geographical environment, historical pattern, and ethnic culture are the basic impact factors. At macroscopic level, regulation of urban planning, transformation of industrial development policy, and housing supply institution have significant influences.
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Sea level change in China adjacent seas studied using satellite altimeter, satellite gravity, and thermohaline data
- CHANG Le, QIAN An, YI Shuang, XU Changyi, SUN Wenke
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2017, 34 (3):
371-379.
DOI: 10.7523/j.issn.2095-6134.2017.03.011
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Abstract (
357 )
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We study the sea level changes of China adjacent seas using satellite gravity data, satellite altimeter data, and thermohaline data. The results show that, compared with the global mean sea level rising rate during the period from 1993 to 2014, the sea level rising rate of the South China Sea is very fast, while the rates of the Yellow Sea and East China Sea are slow. The results and analysis based on these three kinds of data indicate that water mass change is the main reason for the sea level rising from 2003 to 2012, but the sea level of the South China Sea is mainly influenced by steric sea level change. The sea level interannual changes of the coastal waters of China have some correlations with ENSO, but the correlation coefficients are small. The sea level of China adjacent seas declined during the period from 2000 to 2005, and then rised again.
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Analysis of lithospheric rheological structure and dynamics of the Challenger Deep in Mariana trench
- GAO Lingju, ZHANG Jian, WU Shiguo
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2017, 34 (3):
380-388.
DOI: 10.7523/j.issn.2095-6134.2017.03.012
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Abstract (
282 )
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Mariana trench is the key area of tectonic evolution in the western Pacific ocean plate edge trench-arc-basin system. The Challenger Deep in the southernmost Mariana trench is the deepest point on the Earth's surface, and the structural convergence point of Mariana trench, Mariana arc, Mariana trough, west Mariana ridge, and Parece Vela basin. It is important for understanding Challenger Deep formation evolution to study Challenger Deep lithospheric rheological structure and dynamics. In this work, based on the analysis of gravity and magnetic data, we obtained the rheological characteristics of the equivalent viscous coefficient and the lithosphere strength of the Mariana trench-arc-trough-basin system. We drew the characteristics changing with depth and the abrupt form of Wadati-Benioff zone under the trench through the calculation of the seismic data. The calculation results are showed as follows. 1) Corresponding to Mariana trench-arc-trough system, the free air gravity anomaly formed an eastward protruding arc anomaly zone, which showed beaded linear characteristics. The abnormal value was high in the middle and low at both sides. 2) The lithosphere integrated intensity ratios at different depths reflected that on the north and south sides of the trench the upper crust was hard and the lower was soft, and on the middle trench the upper crust was soft and the lower was hard. We calculated the equivalent viscosity coefficients using a given strain rate, and found that the value in the east was high and the value in the west was low, which illustrated that the deformation of the west side of the crust is more easily than that of the east side of the crust. With large lithosphere strength, high equivalent viscous coefficient, and hard upper crust and soft lower crust rheological characteristics, Challenger Deep provided important conditions for bending, tearing, and rapid reversal of the plate subduction area. The analysis of seismicity and gravity profile showed that the lithosphere cumulative stress intensity and effective viscosity coefficient at the Challenger Deep would make the Mariana trench subduction zone bending and cracking or partially turning toward the south and steeping under the action of gravity.
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Image quality assessment based on Gaussian-Hermite moments and HVS
- LI Guoqing, ZHU Baiming, QI Honggang, HUANG Xin, YIN Hongsheng
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2017, 34 (3):
389-394.
DOI: 10.7523/j.issn.2095-6134.2017.03.013
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Abstract (
292 )
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We present a new full-reference image quality metric using Gaussian-Hermite moments and human visual system (HVS). Orthogonal moments are powerful tools in pattern recognition and image processing applications. Low-order moments well characterize features of an image and can be used to assess the image quality accurately. Firstly the proposed method obtains the feature of low-order moments through computing the continuous orthogonal moment energy differences between two images. Then, by combining the masking effect of human visual system (HVS), the different weighting factors are assigned to different areas in an image. Finally, image quality scores are derived by the weighted average of the continuous orthogonal moment energy differences in all the areas of the image. The performance of the proposed method is evaluated on several public databases. Experimental results and comparisons demonstrate the efficiency of the method.
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Design and implementation of postal delivery big data analytic system based on Hadoop
- WANG Weifeng, YANG Lin
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2017, 34 (3):
395-400.
DOI: 10.7523/j.issn.2095-6134.2017.03.014
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Abstract (
350 )
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Facing massive postal delivery data, the existing data warehouse system based on the traditional relational database has problems of high construction cost and analysis capacity bottleneck. Nowadays, Hadoop is widely used in large data storage and analysis, and it has the advantages of high scalability, high performance, and so on. On the basis of studies of the open source framework of Hadoop, combining with practical engineering project, we proposed a delivery data analysis system based on Hadoop. we implemented some parts of the system. We obtained the performance parameters of this system. The parameters can be widely used in future building of the project.
