Table of Content

25 December 2013, Volume 41 Issue 12

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Chemistry,Chemical & Energy Engineering

Effect of pH Value on Cellulase Adsorption on Wheat Straw Alkaline Lignin

2013, 41(12):  1-5.  doi:10.3969/j.issn.1000-565X.2013.12.001

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Quartz crystal microbalance was used to detect the adsorption capacity and configuration variation of cel-lulase on wheat straw alkaline lignin film,and the effect of pH value on the adsorption was investigated.The resultsindicate that (1) there exists electrostatic repulsion between cellulase and wheat straw alkaline lignin when the pHvalue ranges from 4.8 to 6.0; (2) the electrostatic repulsion becomes stronger and the cellulase adsorption on thelignin film becomes more unfirm at a higher pH value,thus loosening the adsorbed film and decreasing the adsorp-tion capacity; and (3) high pH value benefits the desorption of cellulase from wheat straw alkaline lignin film andits recovery.

Effect of Relative Molecular Mass of Amino- Sulfonic Acid- Based Dispersants on Performances of Ceramic Slurry

2013, 41(12):  6-11,23.  doi:10.3969/j.issn.1000-565X.2013.12.002

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Five fractions of amino- sulfonic acid- based dispersant ASP with different relative molecular mass wereobtained via ultrafiltration,and their influences on the application performances of ceramic slurry were analyzed,with the corresponding mechanism being explored by analyzing the adsorption amount and the Zeta potential of thesefive ASP fractions on black mud particles.The results indicate that (1) the ceramic slurries added ASP fractionswith high relative molecular mass (more than 10000) are of less outflow time,high fluidity,dispersion andlow thixotropy; (2) the adsorption amount of ASP on black mud particles may increase with the relative molecularmass of ASP,thus improving the Zeta potential between black mud particles and enhancing the steric effect,whichmakes ceramic particles disperse better; (3) ASP without ultrafiltration possesses better dispersion property thaneach ultrafiltrated fraction,which means that the ASP fractions with different relative molecular mass work together toendow the ceramic slurry with best performance.This may be related to the improvement of adsorption amount due tothe multi- layer adsorption of ASP fractions with different relative molecular mass on the ceramic particle surface.

Investigation into Co- Combustion Kinetics of Paper Mill Sludge and Straw via Thermogravimetric Analysis

Li Yu- zhong Ma Xiao- qian Xie Ze- qiong Cai Zi- lin

2013, 41(12):  12-17.  doi:10.3969/j.issn.1000-565X.2013.12.003

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In this paper,the combustion characteristics and the kinetics of paper mill sludge,straw and their mix-ture were investigated by means of comprehensive thermogravimetric analysis.The results indicate that (1) thereexist three obvious weightlessness peaks in the combustion curve of paper mill sludge,which correspond to themoisture exhalation,the combustion and exhalation of different volatiles,and the combustion of a small amount offixed carbon and nonflammable organic matters; (2) the ignition temperature of paper mill sludge is only 5.1 ℃higher than that of straw; (3) the addition of straw in the sludge has little effect on the ignition characteristics butsignificantly decreases the burnout temperature of the sludge; (4) the activation energies of sludge and straw firstdecrease and then increase with the increase of conversion rate,and vary in the ranges of 97.0 ～203.7kJ/mol and132.6 ～253.0kJ/mol,respectively; and (5) the average activation energy of the mixture of paper mill sludge andstraw does not monotonically increase with the dosage of paper mill sludge.

Surface Activity of Hydroxypropyl Methylcellulose at Different Interfaces

Ye Jun Li Qing- yong Xiong Jian

2013, 41(12):  18-23.  doi:10.3969/j.issn.1000-565X.2013.12.004

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The dynamic contact angle of hydroxypropyl methylcellulose (HPMC) powders on water surface,as wellas the air- water and the oil- water surface tensions of HPMC aqueous solution,were investigated at different concen-trations and pH values.The results show that (1) the wettability of HPMC powders is not strong enough and isslightly affected by the pH value; (2) the contact angle reaches its minimum 86.380° at pH 4.00; (3) the sur-face tension of HPMC aqueous solution mainly depends on the change of molecular chain conformation in the inter-facial area and varies with both the pH value and the concentration; (4) the air- water surface tension increaseswith the pH value at the mass concentration of 0.1% and shows a V- shaped variation with the pH value at the massconcentration ranging from 0.3% to 1.0%,which illustrates the complex change of HPMC molecular chain confor-mation in the interfacial area; (5) the conformation of HPMC molecular chains becomes more complex at the oil-water interface due to the interaction between HPMC and the lipid in the oil; and (6) the oil- water surface tensiondecreases with the increase of pH value that is not less than 6.00,and varies irregularly due to the greater effect ofconcentration when the pH value is less than 6.00.

Phase Balance and Selectivity of CH₄ /CO₂Adsorption on MIL-101

Xia Qi- bin Miao Jin- peng Sun Xue- jiao Zhou Xin Li Zhong Xi Hong- xia

2013, 41(12):  24-28,42.  doi:10.3969/j.issn.1000-565X.2013.12.005

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In this paper,the adsorption isotherms of CH₄ and CO₂ on MIL-101 were obtained by means of the gravi-metric method at 298,303,308 and 313K,and the corresponding isosteric adsorption heat was estimated.Then,the pure gas adsorption was calculated by using the DL- IAST model,and the adsorption selectivity of CO₂ on MIL-101was discussed.The results show that (1) the adsorption capacity of pure CO₂ on MIL-101 is up to 14.51mmol/g at298K and 2500kPa,which is much higher than that on activated carbon,zeolite and molecular sieve under similarconditions; (2) the isotherms of pure CO₂ and CH₄ well accord with the Double- Langmuir model,which shows thepresence of two adsorption sites; (3) the isosteric adsorption heat of CO₂ on MIL-101 ranges from 19,3 to 25,5kJ/mol;(4) as compared with CH ₄ ,CO₂ is of higher surface free energy for its interaction with the framework of MIL-101;(5) the adsorption selectivity index of CO₂ over CH₄ on MIL-101 is up to 5.6 at 298K and 250kPa; and (6) theadsorption selectivity of CO₂ over CH₄ gradually decreases with the increase of pressure and the concentration of CO₂ in CH₄ /CO₂ mixture.

First Flush Effect of Urban Rainfall Runoff Pollution from Campus in Guangzhou，China

Huang Guo- ru Chen Zi- yu

2013, 41(12):  29-35.  doi:10.3969/j.issn.1000-565X.2013.12.006

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This paper deals with the first flush effects of four monitored rainfall runoff events in South China Univer-sity of Technology in Guangzhou from June,2012 to August 2012.The results show that the first flush phenomenaat different degrees exist in TSS,COD,TN,TP,TCu,Zn,total hardness,NO₂^-- N,NH₃- N and SO₄^2-.The analy-sis results of three rainfall events show that the first 20% of the runoff volume carries the pollution load of 7. 0% ～39. 4% for TSS,20. 4% ～56. 0% for COD,13. 8% ～35. 2% for TN and 16. 0% ～35. 2% for TP,while the first30% carries 18. 6% ～56. 1% for TSS,37. 8% ～72. 6% for COD,22. 8% ～43. 2% for TN and 24. 3% ～53. 1% forTP.Moreover,it is demonstrated that,except for a few significant correlative cases,there is no significant correla-tion or only low correlation between the first flush intensity of TSS,COD,TN as well as TP and the weather para-meters such as rainfall time,rainfall volume,average rainfall intensity,maximum rainfall intensity,appearancetime of maximum rainfall intensity and antecedent dry weather period.

Degradation of Diuron via Heat- Activated Persulfate Oxidation

Gao Nai- yun Zhu Yan- ping Tan Chao- qun Xiao Yu- liang Sui Ming- hao

2013, 41(12):  36-42.  doi:10.3969/j.issn.1000-565X.2013.12.007

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Sulfate radical (SO₄^－ · )，a kind of radical with low selectivity and high oxidation reduction potential,can be applied to the removal of nondegradable organics,just like hydroxyl radical (OH·).In this paper,the deg-radation of a typical pesticide diuron by the sulfate radical produced by heat- activated persulfate was investigated,and the effects of temperature,diuron concentration,sodium persulfate dosage,initial pH value and some commonanions (CO₃^2－,HCO₃^－ and Cl^－) in groundwater on diuron degradation were analyzed by experiments.The resultsshow that (1) the degradation of duiron by heat- activated persulfate follows a pseudo first- order kinetic model (r² ＞0.95); (2) the effect of temperature on duiron degradation rate well accords with the Arrhenius model (r²＞0. 95); (3) the apparent activation energy achieves (166.7 ±0.8)kJ/mol when the temperature ranges from 50 to70℃; (4) the pseudo first- order degradation rate increases with the increase of persulfate dosage but with the decreaseof the initial diuron concentration; (5) the observed rate constant achieves the maximum (k_obs =0.003min－1 ) atpH 6/3; and (6) the degradation inhibition by anions follows the order of CO₃^2－＞HCO₃^－＞Cl^－.It is thus concludedthat the heat- activated persulfate oxidation is suitable for the degradation of organic pollutants such as diuron ingroundwater.

Photocatalysis- Fenton Degradation of Papermaking- Reconstituted Tobacco Slice Wastewater Using Fe- Bent

Mo Li- huan Zhou Zhi- ming Wang Yu- feng Lu Li- cheng

2013, 41(12):  43-48.  doi:10.3969/j.issn.1000-565X.2013.12.008

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A heterogeneous Fenton catalyst,namely Fe- Bent,was prepared from Na- Bent through cation exchangeand was characterized by means of scan electron microscopy and X- ray diffraction.Then,the catalyst was used forthe advanced treatment of papermaking- reconstituted tobacco slice wastewater,and a Box- Behnken mathematicalmodel describing the relationship between wastewater COD_Cr and affecting factors was then established via the re-sponse surface analysis,with the photo- catalytic treatment process being finally optimized.The results show that(1) under optimal conditions,that is,an initial pH value of 2.7,a H₂O₂ dosage of 0.2% and a catalyst dosage of1750mg/L,the COD_Cr is as low as 60.44mg/L; (2) only a small amount of Fe ions leach from Fe- Bent during thereaction; and (3) the prepared catalyst can be easily recovered and reused.

Power & Electrical Engineering

Sensorless Control of Permanent Magnet Motor Based on Two- Stage Kalman Filtering

Yi Bo- yu Kang Long- yun Lin Yu- jian Jiang Kai Guo Hong- xia

2013, 41(12):  49-55.  doi:10.3969/j.issn.1000-565X.2013.12.009

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Although the conventional sensorless algorithm based on Kalman filtering (KF) can eliminate the impactof model error and measurement error on the estimated state variables to a certain extent,heavy computation loadand high cost may simultaneously occur.In order to solve this problem and keep the advantages of the original algo-rithm,a novel sensorless control strategy based on the optimal two- stage Kalman filtering is proposed in stationarytwo-phase coordinates for permanent magnet synchronous motor.In this new strategy,stator currents in the stationa-ry reference frame are taken as the full- order states and the back- electromotive- force is taken as the augmented sys-tem state.In order to improve the parameter identification precision,software phase- locked loop is adopted in thecontrol strategy to estimate the rotor speed.Experimental results show that the proposed strategy is mathematicallyequivalent to the traditional Kalman filtering,with an operation time reduction of 24.49%.

Small- Signal Stability Analysis of Micro- Grid with Inverters Employing Droop Control

2013, 41(12):  56-62,69.  doi:10.3969/j.issn.1000-565X.2013.12.010

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Due to the particularity of distributed generators and loads,system stability has become an important fac-tor that restricts the development of micro- grid.In order to implement the small- signal stability of micro- grid duringthe isolated island operation when several inverters participate in the system voltage and frequency control,a small-signal model of micro- grid containing inverters with P- f and Q- V droop control,which takes into consideration thedynamic characteristics of the controller and the network,is established.Then,the model is used to calculate thesystem eigenvalues and analyze the small- signal stability of micro- grid intuitively,with its effectiveness being alsoverified.Moreover,the variation of engenvalues with the system parameters are discussed,and the parameter par-ticipation factors are calculated and are used as the measurement indexes for the optimization design of controllerparameters.The research provides a foundation for the stability improvement of micro- grid.

A New Method to Theoretically Calculate Circulating Current of Sheath of Extra- High Voltage Submarine Cables

Du Zhao- bin Yang Ze- ming Chen Jun Qiu You- qiang Liang Jing- cheng Niu Hai- qing

2013, 41(12):  63-69.  doi:10.3969/j.issn.1000-565X.2013.12.011

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Due to the existence of remarkable current leakage in extra- high voltage submarine cables,the traditio-nal methods to calculate the induced current of cable sheath cannot be utilized directly.In this paper,according tothe structure characteristics and grounding mode of the extra- high voltage submarine cables of Hainan Interline Pro-ject,a new method to theoretically calculate the circulating current of sheath,which takes into consideration thespatial axial current distribution of long submarine core,is proposed,and the mathematical formula of the inductiveelectromotive force of sheath- armor layer of the cable is deduced based on the electromagnetic field theory and thecircuit laws.The results of both the on- site test and the PSCAD/EMTDC simulation demonstrate that the proposedmethod is feasible and effective,and that it may serve as an applicable method for the theoretical loss analysis ofsubmarine cables.

Relay Protection Scheme for Power Distribution Network with Distributed Generations

Liao Zhi- wei Lan Peng- hao Cui Fa- ju Chen Kai Liu Yi- jie

2013, 41(12):  70-74.  doi:10.3969/j.issn.1000-565X.2013.12.012

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With the interconnection of distributed generations (DGs),the network structure and fault current ofpower distribution system are changed,which leads to the mis- operation,malfunction and sensitivity degradation ofprotective relays.In order to quickly clear the fault region and well play a supporting role of DGs for the system,anew protection scheme is introduced based on the traditional relay protection scheme of power distribution system.In the proposed scheme,the directional pilot protection is adopted and a acceleration module,a direction module,a voltage detection module and an inverse time over- current protection module are employed to avoid the fault currentthat cannot be eliminated due to the protection and the breaker malfunction.Simulated results of PSCAD/EMTDCon a 10kV power distribution system with DGs verify the effectiveness of the proposed scheme.

Numerical Analysis of Deformation and Lubrication for Piston Skirt of Two- Stroke Engine

Ji Fen- zhu Du Fa- rong Liu Shen- wei

2013, 41(12):  75-80.  doi:10.3969/j.issn.1000-565X.2013.12.013

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The deformation of piston skirt directly affects the assembly clearance with cylinder liner and the lubrica-tion state during the engine operation.In this paper,by taking a general aviation two- stroke piston engine as the re-search object,a finite element model describing the piston- piston pin- connecting rod- cylinder liner assembly is con-structed,the deformation of piston skirt under different loads is calculated and discussed,and a second- order dy-namic model is set up to analyze the lateral displacement of the piston.Moreover,the thickness and pressure of thelubricant film between the piston skirt and the cylinder liner are simulated.The results show that (1) the mainthrust plane of the skirt is of a deformation varying with the load; (2) thermal load may result in a skirt expansionand mechanical load may cause an expansion of the skirt upper end as well as a contraction of the lower end of theskirt; (3) under coupled thermal- mechanical load,the deformation of the skirt is not the sum of the deformationsrespectively under thermal and mechanical loads but varies complicatedly; and (4) during the operation of the en-gine,a wedge- shaped space may occur between the ends of the piston skirt and the wall of the cylinder liner,whichmakes the appearance of film lubrication between the piston skirt and the cylinder liner possible.

Research on Energy Saving for Clean Air Conditioning System Based on Harmonic Response Method

Ye Can- tao Ma Wei- bin Liu Jin- ping Liu Xue- feng

2013, 41(12):  81-89.  doi:10.3969/j.issn.1000-565X.2013.12.014

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According to the characteristics of the climate in a zone with hot summer and warm winter,a physicalmodel of a clean room was built.Then,based on the harmonic response method,a numerical calculation of thehourly cooling and moisture load in the modeled clean room with a clean air conditioning system was carried out.Moreover,the effects of the building envelope and the hydrothermal process on the hourly cooling load were ana-lyzed,with the results being finally compared with the actual operation data.It is found that (1) the exterior win-dow shades are of great energy- saving potential,with an indoor hourly cooling load reduction being up to 13.6%;(2) under the same external conditions,the dedicated outdoor air system is superior to the primary return air sys-tem,with a maximum energy- saving rate being up to 38.3%; and (3) the average calculation error of cooling loadis only 10%,which means that the established physical model is reliable.

Biological Engineering

Incorporation of Endoglucanase E4 into Minicellulosomes by In- Vitro Assembly

Ou Jing- shen Ge Hong Cao Yi- cheng

2013, 41(12):  90-94,100.  doi:10.3969/j.issn.1000-565X.2013.12.015

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Discussed in this paper are the heterologous expression of a truncated scaffolding protein from Clostri-dium acetobutylicum containing a cellulose- binding module and two cohesin modules,and a recombinant endoglu-canase E4SD,a family of 9 cellulase Cel9A catalysis domain from Thermomonospora fusca appended with C.aceto-butylicum dockerin in C- terminal,which are both produced by E.coli BL21 (DE3),and subsequently purified,mixed,and then assembled with minicellulosomes by calcium- mediated cohesin- dockerin interaction ex- vivo.Theresults show that the truncated scaffoldin CipA is successfully assembled with recombinant endoglucanase E4SD toform minicellulosome via cohesin- dockerin interaction,and that,as compared with those in enzyme- free state,theenzyme activities of E4SD in carboxymethyl cellulose hydrolysis and microcrystal cellulose hydrolysis respectivelyimprove by 30% and 200%.Thus,it is demonstrated that noncellulosomal cellulase,especially the cellulase withexcellent enzymatic characteristics from other species,can incorporate into C.acetobutylicum cellulosome by ap-pending a C.acetobutylicum dockerin and can synergize with other cellulase to hydrolyze cellulose more efficiently.

Construction of Recombinant Adenovirus with siRNA Against Collagen I

Yao Yong- chang Zhou Jia- an Chen Xiao- feng

2013, 41(12):  95-100.  doi:10.3969/j.issn.1000-565X.2013.12.016

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As compared with the stem cells from other sources,synovium- derived mesenchymal stem cells(SMSCs) are of higher proliferative and chondrogenic ability.However,SMSCs express Collagen I inherently,which may impair the overall quality of the regenerated counterpart.In order to solve this problem,first,shRNAagainst Collagen I was designed and constructed in the adenoviral vector.Next,linear recombinant adenoviral vectorwas generated by the digestion with enzyme PacI and was used to transfect 293 cells for package. Then,the titrationof recombinant adenovirus was determined,and the corresponding amplification and purification were performed toobtain recombinant adenovirus with high titration.Moreover,fibroblasts and osteoblasts were respectively infectedby the recombinant adenovirus,and fluorescence microscopy was adopted to detect the transfection efficiency.Fi-nally,real- time quantitative PCR experiments were carried out to verify the targeting effect of siRNA.Experimentalresults show that the packaged recombinant adenoviruses are of high transfection efficiency and can successfully en-code siRNA against Collagen I.

Modularity- Based Graph Clustering for Analysis of Gene Microarray Data

Li Li Cao Yi- cheng Mao Xiao- fan

2013, 41(12):  101-106.  doi:10.3969/j.issn.1000-565X.2013.12.017

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As an important clustering algorithm,graph clustering can be effectively applied to protein interactionnetworks and microarray data clustering.In this paper,to overcome the shortcomings of the existing graph cluste-ring methods for gene microarray data,a global graph clustering method based on the modularity and the subgraphsmoothness is proposed.In this algorithm,subgraph smoothness is introduced to avoid the local optimal solution,subgraphs with low smoothness values in the clustering results are split into singletons,and those newly- generatedsingletons are used in the next clustering step.After several iterations,the global optimal clustering result can beobtained.The proposed method is then compared with four commonly- used clustering methods (the classic graphclustering,the k- means algorithm,the SOM algorithm,and the Fuzzy algorithm) on a group of genome expressiondata,and the results show that (1) the proposed method is superior to the other four methods in terms of averagenon- overlap proportion and FOM' value; (2) when the dataset is divided into 39 clusters,the FOM' value of theproposed method is respectively 28.41%,19.21%,9.84% and 24.67% lower than those of the other four me-thods; and (3) the proposed method is of a classification accuracy,which is higher than that of the Fuzzy algorithmand the SOM algorithm,with an execution efficiency similar to that of the SOM algorithm but 5.94% higher thanthat of the Fuzzy method.

Research Progress of Ammonia- Oxidizing Archaea

Luo Jian- fei Lin Wei- tie

2013, 41(12):  107-114.  doi:10.3969/j.issn.1000-565X.2013.12.018

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Nitrification,namely the oxidation of ammonia to nitrite via nitrate,has been suggested to be a key partof the global biogeochemical nitrogen cycle.The cultivation of pure isolates and enrichments of ammonia- oxidizingarchaea (AOA) as well as the discovery of archaeal amo gene in different kinds of environments has proved thecontribution of AOA to the nitrification in the earth.Especially,the abundance of archaeal amo in most environ-ments is higher than that of bacterial amo,and the affinity of AOA to ammonia nitrogen is higher than that of AOB.All these suggest that AOA might predominately contribute to the global nitrification.This paper gives an overviewof the sources and genomic information of pure AOA cultures and enrichments,the AOA taxa based on phylogeneticanalysis,the importance of ammonia oxidation to the environment and the discovery of AOA denitrification.It alsoproposes several research prospects in the future.

Fermentation Kinetics of Pichia pastoris for Production of Xylanase and Corresponding Fed- Batch Strategy

Jiang Xue- bin Lin Jian- cong Liang Shi- zhong

2013, 41(12):  115-119,124.  doi:10.3969/j.issn.1000-565X.2013.12.019

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In order to optimize the fermentation process of constitutive Pichia pastoris X- 33 for producing xylanase 1(XYL1),the fermentation kinetics during the single- tank chemostat cultivation was investigated,and the relation-ship between the specific cell growth rate and the cell productivity as well as the product yield was discussed.Then,based on the fermentation kinetics,batch control scheme was adopted to express XYL1 in a 50- L fermenta-tion tank.The results indicate that (1) the relationship between the specific cell growth rate and the glucose con-centration basically accords with the Monod equation,with a maximum specific growth rate value of 0.35h^-1 and asaturation coefficient value of 0.38g/L; (2) when the specific cell growth rate ranges from 0.024 to 0.212.the ki-netic model of XYL1 formation can be described using a quadratic equation with one unknown; (3) the specificsubstrate consumption rate is linear to the specific cell growth rate; (4) the optimal dilution rate is 0.316h^-1and the maximum volumetric cell productivity is 7.509g/(L·h); (5) the specific cell growth rate achieves 0.156h^-1when the product yield reaches its maximum; and (6) after fermentation,the wet weight of cells and the xylanaseactivity achieve (415 ±12)g/L and (2788 ±85)IU/mL,respectively,which means that XYL1 is successfully ex-pressed with high efficiency.

Physics

Analysis and Evaluation of Minimum- Phase Approximation of Headphone- to- Ear Canal Transfer Function

Zhong Xiao- li Ming Fang Xie Bo- sun

2013, 41(12):  120-124.  doi:10.3969/j.issn.1000-565X.2013.12.020

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In order to simplify the headphone equalization processing in headphone- presented virtual auditory re-plays,the minimum- phase approximation of headphone- to- ear canal transfer functions (HpTFs) was analyzed andevaluated.In the investigation,first,HpTFs for 20 human subjects and three types of headphones were repeatedlymeasured by using the blocked ear canal technique.Then,the reasonability of the minimum- phase approximation ofHpTFs was discussed through correlation analysis and psychoacoustic experiment.Analytical results indicate thatthe mean correlation coefficient between the measured and the minimum- phase- approximated HpTFs is 0.95 in thefrequency range from 0 to 12kHz,which validates the reasonability of the minimum- phase approximation of HpTFs.Moreover,the results of psychoacoustic experiment further demonstrate that there is no audible difference betweenthe measured and the minimum- phase- approximated HpTFs at the frequency below 12kHz.

Thermodynamic Mechanism of Convective Heat Transfer Enhanced by Electric Field

Han Guang- ze Chen Jia- jia

2013, 41(12):  125-128.  doi:10.3969/j.issn.1000-565X.2013.12.021

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Transfer processes can be effectively enhanced by external fields,and the heat transfer process enhancedby electric field is a research hotspot in nowadays.In order to reveal the thermodynamic mechanism of convectiveheat transfer enhanced by electric field,fundamental thermodynamic equations including the influence of electricfield are put forward based on the energy postulate,enthalpy and Gibbs function are redefined with the effect ofelectric field,and the expressions of the partial derivatives of enthalpy and temperature with respect to electricfields are derived.The results indicate that,for most liquids in a valid temperature range,the enthalpy decreasesin isothermal process and the temperature increases in adiabatic process with the increase of external electric field.When an external electric field is applied on the heat release stage,the decreased enthalpy of the liquid mediummeans that more heat can be released,while the increased temperature of it means that the heat release to lowerreservoir tends to be more effective.Thus,it is concluded that the electric field effectively enhances the convectiveheat transfer.Based on the proposed thermodynamic mechanism,a principle diagram is finally presented to de-scribe the convective heat transfer enhanced by electric field.

Correlation Between Ionospheric Scintillation and TEC Depletion as Well as Enhancement in South China

Quan Hong- jun Lin Guo- guo Deng Bai- chang Huang Jiang

2013, 41(12):  129-135,144.  doi:10.3969/j.issn.1000-565X.2013.12.022

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According to the data of ionospheric scintillation and total electron content (TEC) observed from January,2011 to December,2012 by a monitor set at Shenzhen Station as a part of Meridian Space Weather Monitoring Pro-ject in equatorial anomaly regions in South China,the relationship between the TEC depletion and the ionosphericscintillation at the nighttime in South China was analyzed.The results show that (1) there occurs frequent TEC de-pletion simultaneously with the scintillation; (2) the simultaneous occurrence of strong scintillation (S₄ ＞0.6) andTEC depletion is more frequent than that of weak scintillation (0.2 ＜ S₄ ≤0.6) and TEC depletion; (3) when thesimultaneous occurrence appears,a positive duration correlation with a coefficient of 0.97 apparently exists betweenthe TEC depletion and the ionospheric scintillation, and a positive correlation with a coefficient of 0.68 between the ROTI index and the S 4 index also exists; (4) the maximum TEC depletion value is linear to the product of the scin-tillation duration and the maximum S 4 value; and (5) although TEC enhancements are observed at the nighttime inSouth China,they have no significant correlation with the ionospheric scintillation.

Structural Heterogeneity of Open- Source Software Communities Based on Complex Networks

Yang Jian- mei Zeng Jin- qun Zhang Jian- gong

2013, 41(12):  136-144.  doi:10.3969/j.issn.1000-565X.2013.12.023

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People have gradually realized that the world we live in,especially in the current times of the Internetand big data,includes not only a homogeneous Gauss world but also a heterogeneous Pareto world.Aiming at thedebates about the measurement of heterogeneity in the complex network circle,this paper first deals with the mea-ning,classification and basic measurement method of heterogeneity,and then regards the peer production communityof open- source software in the Internet as a new- type organization and hence reveal the heterogeneity of its organiza-tion structure through the heterogeneity meaning and relevant parameters of complex network,with a Codeplex C#community being taken as the example.Finally,the practical steps for analyzing the structural heterogeneity viacomplex network models are summarized,and the physical background and research significance of structural hete-rogeneity of organization are discussed.