Table of Content

20 March 2012, Volume 48 Issue 2

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A Study of Aerosol Effects on Stratocumulus Clouds Using CloudSat and MODIS Data

MA Yue,XUE Huiwen

2012, 48(2):  239-245. 

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Microphysical properties of stratocumulus clouds are investigated using data from CloudSat cloud profiling radar for the subtropical East Pacific region. CloudSat retrieval indicates that droplet number concentration remains approximately constant in the vertical direction. The effects of aerosol particles on cloud microphysical properties and liquid water path are studied using data from the cloud profiling radar onboard CloudSat and data from MODIS. It is found that, for constant liquid water path, increasing aerosols can lead to decreased droplet effective radius. However, the aerosol effect on cloud droplet radii is not significant as seen in previous studies. It is difficult to find the effect of aerosols on cloud liquid water path because the liquid water path itself has high variability in the stratocumulus clouds. In addition, it is found that liquid water path derived from CloudSat is higher than that from MODIS, and that the variability of liquid water path in stratocumulus clouds is greater than that of aerosol optical depth in the ambient.

Analysis of Particle Size Distribution Measurements from a Summer Campaign in Suburban Tianjin

LIANG Si,MA Nan,XU Wanyun,DENG Zhaoze,LIU Pengfei,RAN Liang,ZHAO Chunsheng

2012, 48(2):  246-252. 

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A comprehensive field campaign regarding atmospheric aerosol and chemistry was conducted in suburban Tianjin, from July 11 to August 14, 2009. The dataset of particle number size distributions (0.02?1.00 μm in diameter) was analyzed and parameterized, and was further studied with respect to its diurnal variation and relations with meteorological parameters such as wind speed and wind direction. The hourly-averaged integrated number and volume concentrations are 1.7×10⁴cm^-3 and 59 μm³/cm³ respectively. A diurnal variation of particle number concentration is observed with three peaks (06:00?08:00, 13:00?15:00, and 19:00?21:00), which are highly influenced by traffic density and photochemical nucleation process. Maxima of particle concentration occur with calm winds and show no dependency on wind directions, which suggests that local emission sources contribute mostly to the aerosol pollution. Particle number concentration decreases when wind speed increases, and obtains in a relatively high level when wind from S/SW/SE directions prevails, which implies that local particle concentration is influenced by transport from more polluted areas in the south.

Improved 2nd-Order Multi-bit Noise-Coupled Sigma-Delta Modulator for GSM Standard

LI Hongyi,WANG Yuan,JIA Song,ZHANG Xing

2012, 48(2):  200-208. 

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The authors propose an improved 2nd-order 3-bit noise-coupled SDM in which all the summation before quantizer is moved to the input of the 2nd integrator, and time-constraint of the feedback DAC is relaxed by introducing feedback path and delayed input signal. The modulator was designed and fabricated in a 0.35 μm CMOS process using two active blocks. Under 100 kHz signal bandwidth and 12.8 MHz sampling frequency, 86.4 dB SNDR and 95.8 dB DR can be reached dissipating 9.84 mW power from a 3.3 V supply. The modulator can satisfy the requirements of GSM systems.

Polymer White Light-Emitting Diodes with p-Type Si Anode and Nanometer-Thick Polycrystalline p-Si Anode

GU Yongtao,WEI Feng,SUN Tuo,XU Wanjin,RAN Guangzhao,ZHANG Yong,NIU Qiaoli,QIN Guogang

2012, 48(2):  173-176. 

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Polymer white light-emitting diodes (PWLEDs) with p-type Si and nanometer-thick (~10 nm) polycrystalline p-Si anode are reported. The structures of the PWLEDs are Si anodes/ PEDOT:PSS/ MEH-PPV: PFO/Cs₂CO₃/Sm/Au. PWLEDs are optimized by adjusting the mixture of MEH-PPV and PFO as the active polymer layer. It is found that when MEH-PPV is 0.13%, the PWLEDs show white emission with CIE coordinates of (0.372, 0.391). The optimized p-Si anode resistivity of the PWLEDs is investigated. When the resistivity of p-Si is 0.079 Ω•cm, a maximum currency efficiency of 0.191 cd/A and a power efficiency of 0.131 lm/W are obtained. Furthermore, polycrystalline p-Si anode is optimized by adopting various thickness of the Ni layer, the maximum currency efficiency and power efficiency are raised to 0.371 cd/A and 0.187 lm/W respectively when the thickness of Ni layer is 2 nm. In comparasion with PWLEDs with p-Si anode, the maximum efficiency has raised 94% and 43% respectively.

Surface Plasmon Polaritons at an Antisymmetrical Semi-Infinite Dielectric-Metal Structure

LIANG Qijun,WANG Ruopeng

2012, 48(2):  177-182. 

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High reflectivity of surface plasmon polaritons (SPPs) is realized using an antisymmetrical semi-infinite dielectric-metal structure. The authors present a theoretical treatment of the reflection and transmission of normal and oblique incident SPPs at the antisymmetrical semi-infinite dielectric-metal structure respectively. The electromagnetic field is expressed in terms of complete sets of discrete eigenmodes by limiting the thickness of the dielectric, and the reflection and transmission coefficients matrix are obtained according to the matching condition of the tangential fields. When the thickness of the dielectric approaches to infinity, the approximate analytical expressions are consistent with the digital solutions perfectly. The effect of incident angle to the reflectivity and transmittance of oblique incident SPPs is also analyzed.

Performance Analysis of Opportunistic Relaying with Regenerative Relays in Wireless Networks Based on the Randomly Distributed Nodes

LIU Hong,CHENG Yuxin,REN Shubo,XIANG Haige

2012, 48(2):  183-192. 

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The authors study the transport capacity and reliability of the wireless ad hoc networks using opportunistic decode-and-forward relaying for cooperative communications when the nodes are randomly and uniformly distributed in space; meanwhile, in order to optimize the network topology, maximizing the transport capacity is applied under the connectivity of the whole networks. In the condition of the path loss and block fading channels, the authors derive the outage probability and transport capacity of the traditional relaying with opportunistic relaying and the incremental relaying with opportunistic relaying. The numerical simulation results show that, although the random distribution of nodes destroys the expected diversity gain offered by relaying nodes, the opportunistic relaying performs better than the direct communication in overcoming the channel fading. While the transport capacity of the direct communication decreases monotonically with the node density and the transmission power, the opportunistic relaying should consider the maximum transport capacity for the network topology optimization.

Modeling BPEL and BPEL4People with a Timed Interruptable ?-Calculus

JIN Wei,WANG Hanpin,ZHU Meixia

2012, 48(2):  209-216. 

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To describe formal semantics of business processing execution language (BPEL) and BPEL for people (BPEL4People), the authors introduce the π_it-calculus, a new variant of the π-calculus. The execution of π_it-calculus can be interrupted and can handle timing events as well. Both syntax and semantics of the π_it-calculus are provided. A strong bisimulation relation that specifies when two processes can be considered as the same is also given. The activities of BPEL and BPEL4People are modeled by the new calculus. The formal framework may facilitate the reliability and consistency analysis in BPEL or BPEL4People design process.

Theoretical Analysis of the Electromagnetic Radiation from Dielectric Conical Log-Spiral Antennas

HU Huilin,TAN Yunhua,ZHU Baicheng,ZHOU Lezhu,SHAN Rui

2012, 48(2):  193-199. 

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Finite element and boundary integral equation method (FE-BI) is adopted to analyze the influence of structure parameters on dielectric conical log-spiral (CLS) antennas. Firstly the authors compare the radiation performance of dielectric conical log-spiral antennas to ordinary conical spiral antennas with the same structure and frequency. Then the influence of pitch angle and cone angle on dielectric conical antennas are discussed respectively. Structure parameters with best radiation performance are finally obtained based on numerical simulations under given medium parameters.

Atmospheric Pressure Chemical Vapor Deposition Synthesis of Silica-Sheathed Bismuth Sulfide Nanowires

ZHANG Haoxu

2012, 48(2):  217-222. 

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By introduction of a CuCl-Si mixture and water vapor into the system as the silica source, silica sheathed Bi₂S₃ nanowires with smooth surfaces or decorated with nanobeads were all successfully synthesized with precise control at 450℃ using the cheap BiCl₃ and sulfur powder as the reactants with the atmospheric pressure chemical vapor deposition (APCVD) method. High resolution transmission electron microscope (HRTEM) was used to investigate the details of the products. The mechanism for the precise control to the synthesis process was discussed.

Identity-Based Authenticated Key Agreement Protocols without Bilinear Pairing in Multiple PKG Environments

YOU Juan,XIA Song,LI Junquan

2012, 48(2):  223-230. 

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The authors present an identity-based authenticated key agreement protocol without bilinear pairing in multiple PKG environments. Reduced to the standard computational Diffie-Hellman (CDH) assumption in the random oracle model, the protocol security is given a complete proof based on the security of proposed ID-based exponential challenge-response (XCR) signature scheme and dual challenge-response (DCR) signature scheme. Compared with previous identity-based authenticated key agreement protocols, the new protocol shows better performances.

Response of the Atlantic Thermohaline Circulation to Changes of Atmospheric Green House Gases

ZHU Jiang,YANG Haijun

2012, 48(2):  231-238. 

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The equilibrium response of the thermohaline circulation (THC) to changes of atmospheric Green House Gases is simulated using a fully coupled climate model. The strength of the North Atlantic THC decreases about 20% when the concentration of atmospheric CO₂ doubles and increases about 13% when the concentration halves. The response of the THC is divided into two different stages: the transient stage and the equilibrium stage. The transient response is mainly attributable to the changes of local surface heat flux and freshwater flux in the high latitude of North Atlantic, while the equilibrium response is also relevant to the non-local transport of heat and freshwater by THC itself, with the former acting as a positive feedback and the later as a negative feedback. The slow recovery of THC in the doubled CO₂ experiment implies the role of the positive feedback overwhelms that of negative feedback, while the equilibrium behavior of THC in the halved CO₂ experiment suggests that they cancel each other. In addition, the nonlinear relationship between density and temperature of seawater leads to the nonlinear behavior of the THC responses in doubled and halved CO₂ experiments.

Filling Characteristics and Evolution Analysis of the Early Cretaceous Small Fault Depression in Dongling Region, Songliao Basin

ZHANG Chi,WU Chaodong,XIE Lihua,ZHANG Xi

2012, 48(2):  253-261. 

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Based on the core observation, drilling and seismic data, the sedimentary characteristics and the distribution of sedimentary facies and sedimentary evolution of Huoshiling sequence were studied. The results show that the overlying volcanic rocks widely developed in nearly whole region are member 2 of Huoshiling formation, and member 1 of Huoshiling formation can be divided into five level 4 sequences. Delta facies and lake facies are the mainly sedimentary facies in Huoshiling formation. Due to the small fault’s accommodation space and sediment supply change, the sedimentary evolution in member 1 of Huoshiling formation is divided into two stages: the early LST period of Huoshiling formation is dominated by littoral and shallow lake-half deep lacustrine deposition, and the late HST period of Huoshiling formation is dominated by fan delta deposition. The LST is transgression period, and the HST is retrogression period.

Triassic Tectonic Decoupling in Weiyuan Uplift (Sichuan) and Its Implications

GU Zhidong,YAN Shuyu,ZHANG Bo,ZHANG Jinjiang

2012, 48(2):  262-272. 

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Structural geometry and kinematics analysis show that lower Triassic strata are characterized by nearly N-S trending gently anticlines, while the middle-upper Triassic and Paleozoic strata have sub-E-W or NE trending in the uplift of the Sichuan Basin. These structural patterns indicate that there was a “tectonic decoupling” event during Triassic. Based on structural and sedimentary analyses, it is concluded that event briefly responded to the Indo-China orogeny and resulted in the initiation of the Weiyuan uplift. The close-relationship between the folds and fractures may have important applications in hydrocarbon exploration in Paleozoic strata of the Weiyuan uplift.

Automatic Extraction of Coastline from TM Image Integrating Texture and Spatial Relationship

ZHOU Yanan,ZHU Zhiwen,SHEN Zhanfeng,CHENG Xi

2012, 48(2):  273-279. 

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The authors present an effective approach to extracting coastline from TM imagery, integrating texture and spatial relationship of imagery. Firstly, the image area is classified into two main categories (one is water, the other is land), exploiting the texture and MNDWI, which are extracted from the input image. Secondly, the segmentation above is dealt with locally using mathematical morphology and the small heterogeneous regions in water and land are filled using the region growing method, relying on the spatial relationships and expert knowledge about the coastline. Finally, vectorizing the segmented image generates the final coastline, and the coastline is assessed by the proposed evaluation system, which is found on the matching of two lines. The experimental results demonstrate that the proposed method is able to accurately extract coastlines from TM image of Liaodong Peninsula. Moreover, texture and spatial relationships are useful information for coastline extraction.

Spatial Analysis of Urban Residential Ecological Quality: A Case Study of Shenzhen

TAO Jingxian,WANG Yanglin,LIU Zhenhuan

2012, 48(2):  280-284. 

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Based on the relevant theories of environmental economics and ecosystem services and functions, the article evaluates residential ecological quality within the Shenzhen city using the methods of mathematical statistics and GIS analysis, which helps to demonstrate the spatial distribution of the life quality of the citizens, and thus provide solid evidence for urban planning and policy making. The research is also helpful to other areas in China in that it makes efforts to predict the changing trend of living environment in relatively typical and quickly-developed cities, which reveals the causes and the solutions to the problems. The result shows that the residential ecological quality of Shenzhen decreases all along the southeast area to the northwest area of the whole region in the year of 2005, and meanwhile, communities inside the special zone, on the general, enjoy better living environment than those outside the special zone. As to the cause of the spatial distribution, while the urban plan serve as the fundamental factor and plays a vital role, the way in which the city develops also play active roles in the forming of this pattern. Furthermore, the analyses also shed light on the recipe to improve the current unsatisfying status: planning for more ecological lands like wetlands and forests, combined with adjusting the structure of local industries to decrease the pollution released by manufacturing in this region will serve as two efficient policy direction, which is sure to bring about a better living environment and contribute to a better life standard for all of the citizens in Shenzhen.

Pastoralists’ Perception and Adaptive Actions to Climate Change in Arid and Semi-arid Area: A Case Study in Hexigten Banner, Inner Mongolia

WANG Tao,LI Wenjun,LI Yanbo

2012, 48(2):  285-295. 

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Through case study with participant observation, semi-structured interview, questionnaire survey and multi-stakeholder interview, pastoralists’ perception and adaptive actions to climate change were described and recorded in the steppe region of Hexigten Banner, Inner Mongolia. Pastoralists’ perception was compared with meteorological data and the disasters’ record. The factors impacting their adaptive capacity were analyzed. The main change of climate according to pastoralists’ perception was aggravated drought since year 2000, which was described as higher temperature, less precipitation, and the change of wind, cloud and fog. About the temperature, precipitation and the meteorological disaster, pastoralists’ perception was coincident with meteorological data and the disasters’ record. However, since the impacts to eco-systems and livestock husbandry of climate change were more concerned, besides the amount of precipitation, pastoralists stated detailed changes: the frequency, spatial and temporal heterogeneity, fluctuations and cumulative effect of rainfall, and the aggregate effect of precipitation and temperature. Drought has decreased forage production and surface water, under these pressures pastoralists’ adaptive actions were to increase livestock mobility, clarify resources users and purchase forage and grain. The pastoralists were able to cope with climate change, common property rights arrangement; nested management of monitoring and sanction; external support such as projects from the government, market and credit played the key role.

Research on Emergency Response System for Sudden Air Pollution Accidents Based on Rule Engine

LUO Sanbao,XUE An

2012, 48(2):  296-302. 

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According to the characteristics of emergency treatment and disposal for different types of sudden air pollution accidents such as diffusion leaks, fires and explosions, an emergency response system was developed for sudden air pollution accidents based on the rule engine technology. Firstly, a spatial analysis module was introduced to the rule engine to strengthen the expression and analysis abilities of environmental data. Secondly, it summarized 3 categories rules about pollution spread mode selection, classification risk areas and evacuation route optimization, and then a leakage diffusion selection rules was constructed. Finally, based on Drools rules engine technology and WebGIS spatial analysis technology, the emergency response system was implemented. An example application demonstrated that using rule engine technology can improve high efficiency, flexibility and practicality of the emergency response system.

Hydrological Effect Assessment of Low Impact Development for Urbanized Area Based on SWMM

WANG Wenwen,ZHAO Zhijie,QIN Huapeng

2012, 48(2):  303-309. 

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By field monitoring and simulating with SWMM, this research compared storm water runoff under both pre- and post-development conditions, and modeled two LID control alternatives in Guangming New District of Shenzhen to investigate the process of urbanization on the hydrological impact of LID measures and the different effects of rain and flood control. Results show that, watershed peak flow and runoff coefficient increase significantly, and time of max occurrence becomes earlier after urbanization; permeable pavement and sunken lawn can effectively reduce peak flows and runoff coefficient, and can be effective in relieving the pressure rainwater drainage network; combination of them two can do better in flood control, and then increase the amount of rainwater resources utilization.

Prediction of HFC-23 Emission and Analysis of CDM Project Impact in China

FENG Jinmin,YAN Huanghuang,ZHANG Boya,ZHANG Jianbo

2012, 48(2):  310-316. 

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Based on the analysis of HCFC-22 consumption in China, the trend of HCFC-22 production and HFC-23 emission was predicted. It was dwelled upon that the increase of HCFC-22 production was rational, which steam from development of some related sectors in China. Also the abatement effect of Clean Development Mechanism (CDM) project is demonstrated. The result shows that annual reduction effect of CDM project amount to 66.79×10⁶ tons CO_2-eq. However, predicted yield of HFC-23 would be 1.6×10⁴ tons in 2015, with 6×10³ tons would be destroyed by CDM project, and the emission would reach 1×10⁴ tons which equal to 120×10⁶ CO_2-eq. Furthermore, each stakeholder’s standpoint to HFC-23 CDM and how to control HFC-23 emission were discussed.

Factors Affecting Soil Organic Carbon Density (SOCD) and Total Nitrogen Density (TND) in Inner Mongolian Steppe

CHEN Xi,LIU Hongyan

2012, 48(2):  317-324. 

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The authors collected soil samples from 94 profiles in Inner Mongolia covering 4 land use types: cropland, abandoned cropland, artificial forest and steppe, in which steppe can be further classified into sandy steppe and non-sandy steppe. It is found that soil organic carbon density (SOCD) is affected by soil texture. It increases with the content of clay (<2m), fine silt (2-16m) and coarse silt (16-63m). However, total nitrogen density (TND) is affected both by soil texture and land use types. Non-sandy steppe has the highest TND. Cultivation leads to the decreasing of TND but not SOCD. The expected increase in SOCD of artificial forest does not realize. Since the requirement of soil nutrient and water is large, artificial forest may even cause strong negative effects on soil fertility and sustainability. It is also found that soil nutrient decreases when mean annual temperature (MAT) increases. Under global warming, the region may turn to an important carbon source. Soil nutrient decreases with vegetation degradation, so the protection of steppe vegetation from over grazing is very important.

An Empirical Study on Creation Motivations for Links of Tourism Attractions

ZHANG Yi,GAO Yizhao,JIANG Xiaorong,QI Lina,WU Bihu

2012, 48(2):  325-330. 

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Based on the previous research which showed that Link count to an attraction’s website can indicate its tourism attractiveness, the creation motivations for links to A-grade attractions in Beijing are investigated. First, a classification scheme for link creation motivations was created based on attraction’s attributes. Second, the link data were collected by search engines and 485 links were sampled randomly. Last, the links were classified independently by three researchers. The survey results show the majority, over 70%, was created for reasons related to tourism. However, there are differences in proportion of tourism motivation for creating links to different types of attractions. The more functions an attraction offers, the lower proportion of links created for tourism reason it has, e.g., museums and industrial and agricultural tourism demonstration enterprise. If the removal of these two types of attractions, the proportion of tourism motivation could rise to about 90%. The above results demonstrate the significance of link count to attractions is dominated by links created for tourism reason, and it provides evidence in support of attractiveness interpretation of links.

Calibrating Group Attachment Scale: An Application of Item Factor Analysis

LI Tonggui,LIU Yang

2012, 48(2):  331-342. 

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In accordance with Smith et al.’s (1999) paradigm of developing group attachment measurements, the current research developed the group attachment scale (GAS) based on the experience of close relationship inventory which was widely considered as standard measurement of dyadic attachment. To confirm such conjecture, GAS with several criterion scales were tested in a sample of 1571 employees. Data analysis incorporated item factor analysis (IFA) modeling instead of using traditional confirmatory factor analysis (CFA) based on linear regression. Within the framework of structural equation modeling (SEM), IFA could be formalized as a CFA model with latent response indicator which was supposed to be the underlying score externally manifested by categorical response, so it was also called as categorical confirmatory factor analysis (CCFA). The current research applied maximum likelihood estimator to fit a two-factor non-orthogonal CCFA model for GAS. In terms of univariate standardized Pearson residuals, the CCFA model fitted well to the empirical data. However, item and test information still had much to be desired. Validity analysis showed that group attachment moderately correlated with dyadic attachment, which probably indicated their common antecedent attachment theory. Besides, group attachment avoidance had stronger association than group attachment anxiety with group identification measures, but unexpectedly stronger with the sum-score of Rosenberg self-esteem scale. Possible reasons for such observations were further discussed.

Effect of Different Kinds of Extra Carbon Sources on the Biomass Production and BaP Removal by Bacillus pumilus Strain Bap9

ZHU Tingting,NI Jinren

2012, 48(2):  343-346. 

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Batch experiments were conducted in order to investigate the effects of extra carbon sources on benzo[a]pyrene (BaP) biodegradation by Bacillus pumilus strain Bap9, which was isolated from polluted soil collected from open-air barbecue market. In the culture system under initial BaP concentration of 40 mg/L, the addition of sucrose, glucose, maltose reduced the degradation rates, the presence of soluble starch had no obvious effect on the biodegradation, while the supplement of sodium acetate increased by 8.8% of the degradation rates most effectively. However, if the concentrations were too high, sodium acetate would show the inhibition of biodegradation. The supplementation of phenanthrene (Phe), was more effective on increasing the degradation rate than sodium acetate of the same concentration. The biodegradation rate of BaP increased 26.4% after a 20 days incubation period , while Phe of 40 mg/L was used as the co-metabolism substrate.