Table of Content

20 March 2011, Volume 47 Issue 2

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Study on Turbulent Structures and Energy Transfer during an Advective Fog Period

WU Bingui,ZHANG Hongsheng,WANG Zhaoyu,ZHU Hao,XIE Yiyang

2011, 47(2):  295-301. 

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Based on the data collected at a 255 m tower during an atmospheric boundary layer experiment in Tianjin, the micro-structures of turbulence and characteristics of energy transfer during an advective fog process in February 2006 are analyzed. Combined with the cold front passage, clear and weak wind condition, and light fog, the characteristics of turbulent kinetic energy during the fog process are discussed. The results show that the peak frequencies of energy spectral density for all directions are at the higher frequency part during the fog occuring, while being at the lower frequency part before the fog formation and after the fog dissipation. Compared with the velocity spectra, the peak frequency change of temperature spectra is larger than that of velocity spectra before the fog formation. As the fog dissipates, the peak frequency of temperature spectra is lower than that of velocity spectra. During the fog, the mean kinetic energy shows a smaller value, while the turbulent disturbance is active, and the vertical turbulent momentum transfer is dominant. The abrupt rising of mean and turbulent kinetic energy before the fog formation may be regarded as the starting signal of advective fog.

Anisotropic Correction for Resistivity Logging of Horizontal Well in Thin Interlayer Reservoir

KONG Fanda,HE Tao,JIANG Hongfu

2011, 47(2):  302-308. 

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In order to correct the anisotropic resistivity for horizontal well logging in thin interlayer oil reservoir, firstly the crossing points of the horizontal well track with target formations were determined by analyzing the response characteristics of logging parameters, and a series of virtual vertical wells at these locations were set to get an accurate 3D lithology model adapting the horizontal well track survey. Secondly, a 3D relative resistivity anisotropic coefficient volume was calculated based on the deep resistivity measured from neighbouring vertical control wells for target formations. Finally, the horizontal resistivity logging for varying angles between the well track and formation beddings was calculated. This method was successfully applied to horizontal wells of Zhaozhou oil field and the corrected resistivity showed improved responses on lithology and pore fluid. Thus, it would increase both accuracy and reliability of the reservoir evaluation for horizontal wells.

Lightning Function Family

YUE Zengyuan

2011, 47(2):  193-200. 

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A family of functions, where each function is everywhere continuous but nowhere differentiable, is constructed. Compared to the existing examples of non-differentiable continuous functions, the functions in this family have the following features. 1) Each function in this family has a lightning-like intuitive image and is therefore called a Lightning Function, and the whole family is called Lightning Function Family. 2) It can be intuitively understood why each lightning function is everywhere continuous but nowhere differentiable. 3) Each lightning function is quasi-self-similar in the sense that a local image would become identical with the global image by stretching in the horizontal and vertical directions. 4) Each lightning function can be obtained by infinite number of repetitions of a corresponding Lightning Transformation starting from the straight segment between the points (0, 0) and (1, 1). Fractal properties of Lightning Functions are also discussed based on Mandelbrot's definition of fractal dimension for coastlines.

True Tailbend Occurred in the Late Triassic: Evidence from Ichthyosaur Skeletons of South China

JI Cheng,JIANG Dayong,HAO Weicheng,SUN Yuanlin,SUN Zuoyu

2011, 47(2):  209-314. 

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Here the true tailbends are reported in two complete skeletons of Guanlingsaurus from the late triassic of Guizhou Province, southwestern China after accurate observations, measurements and comparisons with Ichthyosaur of early jurassic. They have acquired the wedge-shaped centra and the angles in these tailbends are around 15°while those in jurassic types are around 60°. This study shows for the first time that wedge-shaped tailbend centra already existed in merriamosaurs as early as late triassic time, probably being a result of coevolution between ichthyosaurs and the environment. The occurrence of the true tailbend connected triassic and jurassic ichthyosaurs that used to be considered as separate groups in previous literature. The present finding also suggests the monophyly of ichthyopterygia.

Dual-Window K-Space Weighted Gating Navigator Technique on Right Coronary MR Angiography at 3.0 T

ZHAO Xuna,ZU Donglin

2011, 47(2):  217-223. 

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To shorten scanning time and increase the feasibility of experimental results, dual-window K-space weighted navigator technique (DKWN) on right coronary MR angiography at 3. 0 T was implemented. The characteristics of DKWN technique and conventional navigator technique with fixed gating window in 25 normal subjects were evaluated. Compared to the conventional navigator sequence, DKWN sequences increase the scanning efficiency by 30% ( p < 0. 05), while maintaining good image quality; further the corresponding scanning time decreases from2. 12 to 1. 64 min (p < 0. 05). The coronary artery lengths and diameters do not show statistically significant differences between the two techniques ( p > 0. 05).

Propagation Properties of Surface Plasmon Polaritons in Cylindrical Gold Nanowires

SUN Baoqing,GU Ying,GONG Qihuang

2011, 47(2):  224-230. 

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The authors theoretically studied the propagation properties of surface plasmon polaritons (SPP) in cylindrical gold nanowires at the wavelength of 632.8nm. By solving the Maxwell's equations, the propagation constant of the SPP modes and the propagation properties of the modes are obtained, including their propagation lengths and effective radiuses. The authors find the change of the modes' properties influenced by the structure of the waveguides and the dielectric, which is a trade-off between the modes?propagation length and effective radiuses. Through calculation, the authors find out good propagation properties of the surface plasmon modes under certain dimension. When both the radius of the gold core and the thickness of the SiO₂ layer is 40 nm, HE₁₁ mode can travel for 103. 6 μm, with an effective radius of only 642 nm.

An Improved Salsa20 Stream Cipher

ZHANG Zhongya,GUAN Jie,DING Lin

2011, 47(2):  201-207. 

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A new structure is presented for stream cipher. The stream cipher Salsa20 is improved based on the new structure. The results show that the improved algorithm can resist slide attack efficiently as the slid pairs are reduced from 2²⁵⁶ to 0. Furthermore the improved algorithm can resist 2nd preimage attack and differential cryptanalysis. The improved stream cipher doesn't change the encryption speed, which has been tested experimentally.

Effect of Spin Polarization on the Conductance of the Quantum Dot System

CHEN Xing,GUO Wei

2011, 47(2):  213-216. 

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By using non-degenerate Anderson model, the influence of local spin polarization on the conductance of quantum dot system was study. Based on the truncate approximation and non-condenced condition, the equation of motion gave the approximate solution of Green's functions. Then the power siries expansion of the Green's functions with respect to the splitting of local spin energy was got. Finally, local level splitting dependence of conductance from Landauer formula was obtained.

Local Regularity for the Linear Second-Order Parabolic Equation in Nondivergence Form

YAO Fengping,ZHANG Kejing

2011, 47(2):  208-212. 

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By developing the method of Acerbi et al, the authors obtain local regularity in Orlicz spaces for the linear second-order parabolic equations with small BMO coefficients in nondivergence form. Such regularity estimates can be applied to the study of the existence of solutions in W^2,1_p.

ReSim: A Simulator Platform for Reconfigurable Processor

DAI Peng,WEI Lai,XIN Lingxuan,WANG Xin’an,ZHANG Xing

2011, 47(2):  231-237. 

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A hierarchically modularized design based clock accurate simulator platform ReSim is proposed for the flexible interconnection, expandability and dense computational characteristics of reconfigurable processor ReMAP. The simulator is designed under three hierarchy software framework, which contains interconnect modules to accelerate various interconnection architecture evaluation, control modules to simulate different compute model. The simulator can quickly establish the reconfigurable processor model and test the function validity of processor architecture, as well as evaluating the performance under the control of clock driving module for the whole system. The result shows that ReSim can support the evaluation and simulation of the reconfigurable processor architecture ReMAP-2 effectively.

Particle Swarm Optimization Based Learning Algorithm for Process Neural Networks

LIU Kun,TAN Yin,g HE Xingui

2011, 47(2):  238-244. 

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This paper proposes a new learning algorithm for process neural networks (PNNs) based on particle swarm optimization (PSO), called PSO-LM. After the orthogonal basis function expansion to the input functions and the weight functions of the PNN, the structure parameters and other parameters in the PNN will be formed as a particle, and globally optimized by PSO. This algorithm does not need any gradient calculations or the manual control of the network?s structure. The global learning capability and the convergence capability of the PNN can be guaranteed by the capabilities of PSO, so the PSO-LM can better develop and improve the approximation capability of the PNN. According to two practical prediction applications, PSO-LM can outperform the existing basis function expansion based learning algorithm ( BFE-LM) for PNNs, and the classic back propagation neural networks (BPNNs) on predictive accuracy.

Spatial Temporal Characteristics of Tropical Disturbances over the Northwestern Pacific during 2000-2008

ZHANG Chao,ZHANG Qinghong

2011, 47(2):  278-286. 

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Based on the Tropical Storm and Hurricane WX products ( WX-TROPL) , 596 tropical disturbances generated over the Northwestern Pacific during 2000-2008 are analyzed, 456 of which occur in summer half year (May to October). The frequency peaks in August ( 11. 6 per year in average) . There are 369 disturbances generated in the monsoon trough. The average development rate of disturbances is 43. 8% , while the peak value 54. 8% appears in August, and the neap value 20% appears in February. The ENSO3. 4 index at the end of year has a high negative correlation with the frequency of disturbances in the next summer half year, and the coefficient reaches 76. 1% . The stronger peak value of La Nina's signal appears, and the longer it lasts, the higher frequency of disturbances in the next summer half year turns up. Over the Northwestern Pacific, most disturbances generate in the South of 15°N in winter half year, and scatter between 0°-35°N in summer half year. Using data derived from satellites, it is implied that the tropical disturbances over the Northwestern Pacific all generate in the high value areas of lower level vorticity and latent heat release.

Overview of Heavy Molecular States

SHEN Leilei,CHEN Xiaolin

2011, 47(2):  373-377. 

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Many new hadron states were observed by the BaBar, Belle, CDF, D0 collaborations in recent years, some of which did not fit into the quark model easily. We reviewed our groups systematic work on the heavy molecular states especially X ( 3872) , Y ( 4260) and Z⁺ ( 4430) and discussed the difficulties and challenges in this field and the possible improvement in the future.

Extending Virtual Machine Memory with Hypervisor Exclusive Cache

NIU Yan,YANG Chun,XIA Yubin,CHENG Xu

2011, 47(2):  251-257. 

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It is hard to accurately predict the memory demand of a virtual machine. Moreover, it is not reliable to request other virtual machines to release memory. Under-provision of memory will lead to severe performance degradation. To mitigate the impact, a hypervisor exclusive cache (HECache) is developed to extend the available memory of a virtual machine. A certain amount of memory is preserved as HECache in advance. The failed memory access in the VM is forwarded to HECache. All virtual machines running on the physical machine share HECache and can use it immediately. Through donating a little memory, all virtual machines can use more memory. The experiments conducted with both micro-benchmarks and real applications show that HECache can achieve up to 7. 9 times better performance, and the overhead is not significant compared with allocating the same amount of memory directly to a virtual machine. In addition, HECache is transparent to applications, and is complementary to the existing techniques such as ballooning, page-sharing, hotplug, etc.

Effects of Vertical Distributions of Cumulus Cloud Microphysical Properties on Shortwave Radiative Forcing

ZHANG Shuangyi,XUE Huiwen

2011, 47(2):  263-270. 

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Large eddy simulations were used to get profiles of liquid water content and droplet effective radius in shallow cumulus clouds. Results show that both liquid water content and droplet effective radius increase with height (vertically inhomogeneous). Then the atmospheric radiative transfer model SBDART were used to study the effects of vertical distributions of microphysical properties on radiative transfer. The shortwave radiative forcings from a vertically inhomogeneous cloud and a vertically homogeneous cloud with the same liquid water path were compared. Results indicate that vertical distributions of microphysical properties have significant effects on radiative transfer. When droplet effective radius of the vertically homogeneous cloud is equal to 76% -90% of the cloud-top droplet effective radius in a vertically inhomogeneous cloud, the two clouds have similar radiatve forcing. This means that in global climate models, the assumption of vertical homogeneity of a cloud must be used carefully and the associated droplet effective radius must be about 76% -90% of the observed value at cloud top for shallow cumulus clouds. Results in this study are consistent with previous studies for stratified clouds.

Interaction of Tropical Cyclone and Summer Monsoon over South China Sea

DAI Zhanpeng,ZHANG Qinghong

2011, 47(2):  287-294. 

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Interaction of tropical cyclone and South China Sea (SCS) summer monsoon, especially the mechanism for intensification of low level jet over SCS caused by tropical cyclone landfall, is discussed base on case study and statistical analysis. In case study, different sets of numerical experiments during the landfall of tropical storm BILIS (0604) are carried out using mesoscale model MM5. Result shows that the moist southwestly summer monsoon retarded the decay of tropical cyclone and enhanced the rainfall. On the other hand, the backward reaction from tropical cyclone to low level jet over SCS cannot be ignored. Mesoscale convection systems accompanied with tropical cyclone landfall would enhance the pressure gradient force in low atmosphere over SCS, which would lead to intensification of the low level jet in summer monsoon. Statistical analysis of 30 tropical cyclones with similar track as BILIS dating from 1950 to 2009 also shows that 80% tropical cyclone activities accompany with positive low level wind speed anomaly in SCS.

Classification of Coastal Near-Surface Wind Fields over the China Sea

SHI Hui,CAI Xuhui,SONG Yu

2011, 47(2):  353-362. 

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In order to systematically study the statistical characters of coastal near-surface wind over the China Sea, a division for wind regions and an automated classification for wind fields were realized through cluster analysis. Four wind regions and 31 wind patterns were obtained. Wind regions show the correlations of wind speed among different parts of the China Sea. Identified wind patterns include the typical wind fields of monsoons, and wind fields reflecting frequently occurring synoptic systems. Wind fields in the transition periods between monsoons and wind fields in the whole year were also identified. Besides mean wind speed, other meteorological factors, including temperature and humidity, are also significantly affected by the patterns. Investigation of occurrence frequencies, timing, mean wind speed and wind direction distribution of wind patterns reveal the statistical characters of coastal near-surface wind over the China Sea.

A New Way to Make the Absorption Cell of Rb Frequency Standard

WANG Yanhui,LIU Shuqin,DONG Taiqian

2011, 47(2):  370-372. 

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A new way to make the absorption cell of Rb frequency standard using slow-wave structure is suggested. It will increase the interaction between Rb atoms and microwave field, and then the signal to noise ratio of 0-0 transition spectrum and the short term stability will be improved. It is especially useful for Rb frequency standard working in vaccum conditions.

Application of Molecular Ecological Techniques on the Study of Microbial Nitrification and Denitrification

BAI Yaohui,SUN Qinghua,WEN Donghui,TANG Xiaoyan

2011, 47(2):  378-384. 

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The mechanisms, related enzymes, and research hotspots of microbial nitrification and denitrification are discussed. The operation procedure of molecular ecological technique and its application on the analysis of microbial community structure are summarized. This paper also explores the principles, operation processes, advantages and defects, and application on the study of nitrification and denitrification of three techniques (fluorescent in situ hybridization, denaturing gradient gel electrophoresis, and terminal restriction fragment length polymorphism). Previous studies proved that the molecular ecological technique becomes a powerful tool on the study of nitrification and denitrfication process in the environment.

A Control Scheme for Underwater Wireless Modem with Embedded MicroBlaze Processor

LI Ying,Bridget Benson,YU Dunshan,Ryan Kastner,ZHANG Xing

2011, 47(2):  245-250. 

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The authors present a control scheme for UWModem with embedded processor in FPGA. The scheme builds system structure by choosing suitable communication bus type, and designs rational soft/ hardware cooperating procedure and interrupt controlling signals. The results from soft/hardware co-verification with MicroBlaze soft processor in Xilinx VirtexIV FPGA show that the control scheme can efficiently manager the whole digital signal processing in UWModem and report the situation in real-time with steady performance.

Characteristics of Convective and Stratiform Echoes in Beijing-Tianjin Region

LIN Yinjing,WANG Hongqing,HAN Lei,WANG Yu,ZHENG Yongguang

2011, 47(2):  258-262. 

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The reflectivity fields of Beij ing-Tianjin region during 2005-2007 were classified into convective and stratiform components using an automatic algorithm, and then the vertical profiles and diurnal variation of convective and stratiform echoes in this region were analyzed. The results are as follows. 1) An obvious bright band was in the stratiform profile of Beijing-Tianjin region at about the 4 km altitude. The bright band was strongest in the night local time, while weakest in the morning. 2) In this region, the diurnal variations of both convective area and stratiform area were unimodal. The maximum areas occurred in the local evening, while the minimum occurred near local noon. The variation of stratiform area was about 1-2 hours later than convective area. 3) There were two peaks in the diurnal variation of the ratio between convective and stratiform area. One was associated with the thermal convection in the local afternoon, and the other was connected with the moist mass convection happens in the local evening. Both these two types of convection are tconvective systems in Beijing-Tianjin region.

Research on GRAPES Singular Vectors and Application to Heavy Rain Ensemble Prediction

LIU Yongzhu,YANG Xuesheng,WANG Hongqing

2011, 47(2):  271-277. 

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In order to generate the good initial perturbations of ensemble prediction and use limited ensemble members to simulate the time evolution of the atmosphere probability density function in the phase space, the singular vectors (SVs) method was introduced into non-hydrostatic GRAPES meso-scale model. The basic problem of GRAEPS SVs and the method to construct ensemble members based on SVs were researched. GRAPES SVs were solved for a heavy rainfall case by a southwest China vortex moving on July 2008, and an ensemble simulation experiment was made based on GRAPES SVs. The results indicate that the first 27 GRAPES SVs reflect the key information of analysis error; the root mean square error ( RMSE) of ensemble mean about forecast elements have better forecast skills than control forecast, and its ensemble spread is gradually growth with time evolution, reflecting the key information of forecast error; brier score and ROC skill of rainfall show that this ensemble prediction has higher probability skill, and can provide some guidance for the heavy rainfall forecast.

Meticulous Characterization of Permian Volcanic Rocks Spatial Distribution and Its Geological Significance in the Tarim Basin

LIU Xiao,GUAN Ping,PAN Wenqing,TIAN Wei,HUANG Shaoying,PAN Yun,JING Bing,YU Hongjiao

2011, 47(2):  315-320. 

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Seismic reflection characteristics of Permian volcanic rocks in the Tarim Basin were summarized and illustrated by using large number of exploration data from Tarim oil field, and then logging-seismic integrated recognition model was established. Meticulous characterization of Permian volcanic rocks?spatial distribution was achieved through comprehensive study of outcrop, drilling, logging and 2D seismic data. The Remnants of the Permian basalt in the Tarim basin cover an area of about 2. 46 ×10⁵ km², and the remnants of the Permian rhyolite cover an area of about 4.04×10⁴ km². As Permian stratas are missed in most area of north and east Tarim Basin, original Pemian volcanic eruption area may be much larger than residual area. This study lays foundation for further understanding of Permian volcanism in Tarim basin.

Geochemistry of the Carboniferous Volcanic Rocks of Benbatu Formation in Sonid Youqi, Inner Mongolia and Its Geological Significance

TANG Wenhao,ZHANG Zhicheng,LI Jianfeng,FENG Zhishuo,CHEN Chen

2011, 47(2):  321-330. 

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The Carboniferous volcanic rocks of Benbatu Formation at Chagannuoer in Sonid Youqi, Inner Mongolia, consist of basalts with pillow and massive structure and dacites. The SiO₂ content of the volcanic rocks mainly fallen in two ranges 48. 20% -51. 11% and 64. 66% -65. 42% , showing a bimodal distribution composition. The mafic volcanic rocks are mainly alkaline basalt series, with Na-rich and potassium-deficient. The felsic volcanic rocks belong to calc-alkaline series with high alkali content and about 3% K₂O content. The pillow basalts are characterized by slightly loss LREE, enriched HREE, slightly positive Eu anomalies and high abundances in Hf, Zr and Th (HFSE). The massive basalts are characterized by enriched Rb, Th, Zr, Hf and loss Ta, Nb. The dacites have obvious severity of REE fractionation with Eu negative anomalies significantly, enriched Rb, Th, Pb, Hf, Zr and loss Eu, Sr, Nb, Ta. According to Rb-Sr isochron age, SHRIMP U-Pb zircon dating data and paleontological data, Chagannuoer bimodal volcanic rocks formed in Late Carboniferous, about 313-308 Ma. The characteristics of geochemistry and regional geology suggest that Chagannuoer bimodal volcanic rocks formed in post-collisional extensional setting, so it can be inferred that the Solonker suture zone had ever been closed before the Late Carboniferous.

Volume Intersection Analysis for 3D-Urban-GIS: Implementation and Application

LIU Yiqin,PAN Mao,PENG Bo,LI Yun,XUAN Wenling

2011, 47(2):  331-336. 

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A practical 3D spatial analysis for 3D-urban-GIS named Volume Intersection Analysis is presented. With the Volume Intersection Analysis, two volume datasets are put sequentially in, then a result which describes the intersection information between the two datasets is put out. The result is a collection of relations, and each relation describes that a volume object in the first dataset intersects with one or more volume objects in the second dataset. A robust and fast algorithm for the Volume Intersection Analysis is implemented based on the OO3D data model, and its practicality is verified based on a 3D-urban-GISproject (TG-U-3D). The Volume Intersection Analysis is applied to aid detecting land-use conflicts in urban underground space planning process, and finding out the stratums that city facilities lie in or pass through.

Investigate Study on TP Pollution Load of Poyang Lake by Water and Salt Balance

LUO Dinggui,WU Xuewen,LI Shu,HU Chunhua,ZHOU Wenbin

2011, 47(2):  337-343. 

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Based on 1∶50000 DEM, Poyang Lake Basin was divided into sub-basins by using ARCGIS92. For the balance of the 2008 period, water amount into the lake was revised on the basis of water balance under the condition of water amount into the lake divided into four parts which were rivers runoff (Ganjiang, Fuhe, Xinjiang, Raohe, Xiuhe), interval runoff, groundwater runoff, and precipitation. Further study on TP load of Poyang Lake demonstrated that total TP load into the lake was 7758t, with retention ratio of 10% approximately. The rivers load into the lake accounted for 87% of total TP load, corresponding to Ganjiang river load accounting for 57% of rivers load. Main low water period of rivers runoff mostly took place in January and December. On the basis of using main low water period load of river runoff as sole point source load, it was concluded that annual TP load contributions of point and non-point sources were 39% and 61% respectively.

Emergy-Ecological Footprint Integrated Model for Eco-city Evaluation: A Case of Tianjin City

ZHANG Xuehua,LI Jian,ZHANG Hongwei

2011, 47(2):  344-352. 

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In order to avoid some shortages of traditional ecological footprint model, the authors proposed an integrated model by using emergy theory, which is named as Emergy-Ecological Footprint Integrated Model. In ecological carrying capacity calculation, the proposed model adds the carrying capacity of actual product output and virtual product supply based on material input-output theory and people ’s innovation. In ecological footprint calculation, the proposed model considers waste ecological footprint into evaluation system. Finally, the proposed model is applied in Tianjin eco-city evaluation from 2001 to 2008. The calculating result shows that the ecological carrying capacity is higher than ecological footprint, and ecological surplus is in rising tendency which expresses that Tianj in is in sustainable state.

Cultivated Land Quality Evaluation Based on Raster Data in Coastal Vegetable Production Area: A Case Study in Shouguang City, Shandong Province

TANG Xiumei,CHEN Baiming,LU Qingbin,YANG Ke,LIU Fang

2011, 47(2):  363-369. 

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Taking Shouguang City in Shandong Province as a case study, this paper explores the cultivated land quality evaluation based on raster data in coastal vegetable production area. Evaluation factors are chosen by Delphi approach and their weights are determined by AHP method, consequently, comprehensive evaluation method is applied to the cultivated land evaluation and the grades of cultivated land quality are classified by fuzzy discrimination method based on 50 m ×50 m raster data. The result shows that, the cultivated land quality in Shouguang City is good in general with area of the first and the second grades 54. 76% of the total area, the third and the fourth grades 37. 07% , and the fifth and the sixth grades only 8. 16% of the total area. Cultivated land quality grades have an obvious positive correlation with the intensification of cultivated land use according to their gradual spatial transition from northern coastal area to southern area. This study explores the technical methods of the land quality evaluation based on raster data in coastal vegetable production area and has noticeable significance to the sustainable use of cultivated land resources in intensive agricultural area. Besides, some utilization suggestion is brought out for each grade of cultivated land quality.