Table of Content

25 August 2012, Volume 40 Issue 8

Previous Issue    Next Issue

Electronics, Communication & Automation Technology

An Energy-Balanced Optimal Distributed Clustering Mechanism

Hu Xiao-qing Xu Bu-gong Wen Sha Liu Yong-gui

2012, 40(8):  1-7. 

Asbtract ( 435 )   PDF (986KB) ( 731 )  

Related Articles | Metrics

As the energy imbalance of wireless sensor networks has an impact on the network lifetime,a novel energy-balanced optimal distributed clustering mechanism is proposed by introducing a new energy-balanced index based on the standard deviation of residual energy of nodes. Then,it is transformed into a multi-objective constrained optimization problem,and an adaptive genetic algorithm with Elitist mechanism is employed to resolve this problem. Finally,in Matlab environment,the proposed clustering mechanism is compared with the clustering mechanisms respectively based on the energy consumption and the maximal number of cluster nodes. Simulation results show that the proposed mechanism guarantees energy balance and tracking accuracy and that it effectively prolongs the network lifetime.

Investigation into QoS of Multimedia Sensor Network Based on Differentiated Queuing Service

Tang Lin Jiang Sheng-ming Yang Hua-rong

2012, 40(8):  8-13. 

Asbtract ( 342 )   PDF (629KB) ( 706 )  

Related Articles | Metrics

With the rapid development of wireless multimedia sensor networks,how to guarantee QoS has become a hot research issue. In order to realize the priority service of real-time data,this paper introduces the differentiated queuing service algorithm in wireless multimedia sensor networks. First,the principle of the differentiated queuing service is analyzed. Then,according to the relationship between the transmission rate of data sources and the bandwidth,the relationships among the maximum queue length of nodes,the scalar packet lifetime and the real-time packet lifetime are discussed in three situations. When some conditions of this relationship are satisfied,the realtime packet can be rapidly and timely forwarded. Finally,the correctness and effectiveness of the proposed method are verified by means of simulation experiments.

Look Ahead and Backtracking-Based Orthogonal Matching Pursuit Algorithm

Zeng Chun-yan Ma Li-hong Du Ming-hui

2012, 40(8):  14-19. 

Asbtract ( 509 )   PDF (654KB) ( 1318 )  

Related Articles | Metrics

In the orthogonal matching pursuit ( OMP) algorithm based on compressive sensing,the selection of candidate atoms is very important to the final reconstruction performance. In this paper,a look ahead and backtrackingbased orthogonal matching pursuit ( LABOMP) algorithm is proposed by combining look ahead procedures with the backtracking strategy to update a candidate atom set. In this algorithm,all the iterations are divided into early and upper stages. At the former,the optimal atom is selected by forecasting its final performance in the future iterations,while at the latter,the backtracking strategy is introduced,and a previous wrongly-selected atom is then eliminated once per two iterations. Experimental results show that the proposed LABOMP algorithm is applicable and effective; and that its average exact reconstruction probability for Gaussian or binary sparse signals is respectively 12.5% or 18.2% higher than that of LAOMP ( Look Ahead Orthogonal Matching Pursuit) algorithm at the upper stage because the backtracking strategy overcomes the disadvantage of LAOMP algorithm.

Method Using Derivative Circuit to Reduce Crosstalk Between Transmission Lines in PCB

Wang Ya-fei Chen Yin-chao Yang Shu-hui Yang Hong-wen Li Xue-hua

2012, 40(8):  20-0. 

Asbtract ( 336 )   PDF (842KB) ( 1913 )  

Related Articles | Metrics

In order to reduce the crosstalk between the transmission lines of printed circuit boards ( PCB) ,a method using a RC derivative circuit is proposed based on the derivative-transmission characteristics of the crosstalk. In this method,first,by analyzing the crosstalk-cancellation principle,a RC derivative circuit at the end of the transmission line is employed to obtain the derivative of the signal received on the aggressor line,thus generating a derivative signal with approximate amplitude and opposite phase to the far-end crosstalk signal on the victim line. Then,the derivative signal is adopted to cancel the crosstalk signal,so that the crosstalk is reduced. Meanwhile, an approximate formula is presented for calculating the parameter value in this crosstalk-cancellation derivative circuit. Simulated and experimental results show that the proposed method can attenuate the crosstalk peak by more than 10 dB; and that,as compared with the traditional methods using physical structure to reduce crosstalk,the proposed method is of a greatly-improved cancellation effect and the corresponding circuit is easy to realize with a low cost.

Cognitive Radio Spectrum Allocation Algorithm Based on Licensed User Activities

Wang Yao Zhang Zhong-zhao Ma Lin Chen Jia-mei

2012, 40(8):  26-31. 

Asbtract ( 395 )   PDF (580KB) ( 969 )  

Related Articles | Metrics

By taking into consideration the influence of the handoff probability of licensed user's working states on the spectrum allocation in cognitive radio ( CR) networks,this paper proposes a new cognitive radio spectrum allocation algorithm. In the algorithm,based on the definition of income expectation,two new utility functions are presented from the perspective of probability,which respectively reflect the total average channel income expectation and the fairness of the income expectation of cognitive systems. Then,some specific steps of the proposed algorithm are provided. Simulation results show that,as compared with the traditional channel allocation algorithms,the proposed algorithm has an obvious advantage in terms of the total spectrum utilization in the cognitive system; and that it displays excellent system fairness when the licensed user’s working states frequently change,which means that the proposed algorithm is of more practical significance.

Modeling and Boundary Control of a Marine Riser

Wu Xin-sheng Li Lin-ye Liu Yu Gao Hong-xia

2012, 40(8):  32-38,62. 

Asbtract ( 295 )   PDF (973KB) ( 978 )  

Related Articles | Metrics

In order to accurately describe the dynamic characteristics of marine risers,a marine riser model coupling time-varying internal flow and ocean current dynamics is proposed based on Hamilton principle. This model is described with a set of partial differential equations ( PDEs) and a set of ordinary differential equations,and it is infinite-dimensional. Then,based on the proposed model,the boundary controllers in the longitudinal and lateral directions are designed to reduce riser vibrations,respectively by means of the boundary control technique and the Lyapunov method. Consequently,the stability and uniform boundness of the riser system are proved via Lyapunov method. Finally,the effectiveness of the proposed model is verified by simulated experiments.

Computer Science & Technology

Visual Saliency-Based Detection of Text Region in Natural Scene Images

Min Hua-qing Zheng Hua-qiang Luo Rong-hua

2012, 40(8):  39-45. 

Asbtract ( 398 )   PDF (1484KB) ( 2274 )  

Related Articles | Metrics

Extracting text information from images captured in natural scenes is helpful for the content analysis of images. In this paper,according to the fact that the texts in images is often salient in local regions,a novel visual saliency model with multi-scale bounding box is proposed,based on which a new method combining the edge and texture information is designed for the candidate text detection. In this method,first,Lab color space is used to construct the edge and textural information-based image homogeneity,and by using this characteristic,the image is mapped into the homogeneity domain. Then,the proposed model is employed to generate average homogeneity images. Finally,the weighted Euclidean distance between the homogeneity image and the average homogeneity image is determined,and is taken as the saliency measure to extract text regions. Experimental results of natural scene images show that,as compared with the text detection methods based on the edge or the homogeneity,the proposed method can better restrain the background noise,which helps to further segment the text regions from the background and achieve more accurate text location.

In-Plane Rotary Face Recognition Based on 2DNPP and Trace Transform

Shi Zhan Du Ming-hui Liang Ya-ling

2012, 40(8):  46-50. 

Asbtract ( 394 )   PDF (514KB) ( 1305 )  

Related Articles | Metrics

As it is difficult to recognize the facial image with a random rotation angle in a plane,a method integrating 2DNPP with Trace transform is proposed for the extraction and recognition of rotation-invariant features. In this method,first,the image is dealt with through the first and the second Trace transform. Then,the matching calculation of the double Trace feature is carried out,thus achieving a feature,which not only is robust to in-plane rotation but also can preserve most information of the raw image. Finally,the classification and dimension reduction are conducted by means of 2DNPP. The proposed method is compared with SIFT,pseudo-Zernike methods on frontal,rotary and noisy facial image databases. The results show that,on the ORL image database with a random rotation angle,the proposed method has a recognition rate of 96% as well as a strong robustness to white noise.

Multi-Focus Image Fusion Methods Based on Compressive Sensing Theory

Sun Ji-feng Hong Bo-yu

2012, 40(8):  51-55. 

Asbtract ( 388 )   PDF (478KB) ( 1071 )  

Related Articles | Metrics

Compressive sensing ( CS) theory is a novel theory used for collecting,encoding and decoding sparse or compressible signals. In this paper,a novel multi-focus image fusion method is proposed based on the CS theory. The method include the compressive sensing-based transform,pixel-level fusion and sparse reconstruction of the fused image,and,specially,performs the fusion by means of the weighted method,the maximum value method and the coefficient judgment method. Then,some image fusion experiments are carried out to compare the above-mentioned method with the wavelet transformation-based image fusion method and other compressive sensing fusion methods. The results show that the entropy obtained through the weighted method is the highest while that through the maximum value method is the lowest; and that the entropy of the image fused according to the CS theory is higher than that through the same fusion method in wavelet.

Nighttime Pedestrian Detection Method for Driver Assistance Systems

Zhuang Jia-jun Liu Qiong

2012, 40(8):  56-62. 

Asbtract ( 325 )   PDF (835KB) ( 1647 )  

Related Articles | Metrics

In driver assistance systems,real-time and accurate pedestrian detection is required. In this paper,by taking advantage of the low complexity of a knowledge-based detection method,a nighttime pedestrian detection method for monocular far-infrared video data is proposed based on the probabilistic template matching. In this method,according to the distribution of intensity in pedestrian samples,a local dual threshold segmentation algorithm is adopted to extract the candidate regions that may contain pedestrians. Then,multi-scale probabilistic templates are established based on the moving directions of pedestrian samples and are employed to recognize the potential pedestrians from the candidate regions. The establishment mode of probabilistic templates alleviates the large withinclass variability of pedestrian samples,thus improving the induction abilities of the probabilistic templates for the appearance of pedestrians. In order to further improve the detection accuracy,the probabilistic template matching is integrated with the object-tracking algorithm,which results in more robust final decision through the multi-frame validation. Experimental results show that the proposed method can realize a real-time pedestrian detection with a low computation cost; and that it achieves a detection rate of more than 90% at the false alarm rate of less than 10% on suburban scenes while a detection rate of about 75% at the false alarm rate of about 22% on urban scenes.

Online Object Tracking Algorithm Based on Biologically-Inspired C2 Feature

Xing Xiao-fen Qiu Suo Guo Kai-ling Xu Xiang-min

2012, 40(8):  63-68,75. 

Asbtract ( 387 )   PDF (730KB) ( 1042 )  

Related Articles | Metrics

In the existing online object tracking algorithms,tracking deviation commonly occurs when there exists a complex deformation of object appearance. In order to solve this problem,this paper employs robust features to describe the object appearance. First,the perception mechanism of the ventral pathway of human visual cortex is imitated,and C2 feature,which is invariant to position and scale and can distinguish complex shapes,is introduced. Then,a novel online object-tracking model based on a cognitive patch set is put forward to recognize C2 feature. In this model,the importance of a cognitive patch is estimated according to its role in the object recognition,and based on the estimated results,online elimination and update of cognitive patches are realized. Meanwhile,an online object /background classifier is adopted to distinguish new candidate patches,thus solving the problem of the error accumulation resulting from the participation of the background part of the object region in the model adjustment. Simulated results indicate that the proposed method is robust and effective in the presence of complex object deformation and severe occlusion.

Distance-Based Integration Algorithm for Topology Discovery of IPv6 Campus Network

Dong Shou-ling Li Jia Zhang Ling

2012, 40(8):  69-75. 

Asbtract ( 288 )   PDF (401KB) ( 1146 )  

Related Articles | Metrics

Aiming at the shortcomings of the existing methods for IPv6 network topology discovery,a distance-based integration algorithm is proposed for IPv6 campus network. In the algorithm,by using the subnet information of OSPF ( Open Shortest Path First) routing protocol,the results of the Traceroute6-based and OSPF-based topology discovery methods are integrated with the shortest distance between nodes as the metrics. Then,they are adjusted according to subnet prefixes,interfaces,etc. Finally,the proposed algorithm is tested in the real network environment and compared with the hop counts-based integration algorithm. The results show that the proposed algorithm can not only integrate the topology results rapidly and effectively but also improve the integrity and accuracy of the topology information.

Replica Placement for Streaming Media System Based on Tree-Proxies Transparent Service Model

Zheng Wei-ping Fan Bing-bing Qi De-yu Xu Ke-fu

2012, 40(8):  76-81,87. 

Asbtract ( 309 )   PDF (741KB) ( 888 )  

Related Articles | Metrics

According to the routing mechanism in tree networks and the distribution characteristics of streaming media accesses,this paper proposes a tree-proxies transparent service model and discusses the problem of the replica placement for streaming media system based on the model. Then,by analyzing the limitation of the commonly-used prefix placement algorithm on tree-proxies model,a non-fixed-length discontinuous placement strategy and two greedy algorithms,namely HGPA ( Hierarchical Greedy Placement Algorithm) and GGPA ( Global Greedy Placement Algorithm) ,are put forward. HGPA places replica level by level from the bottom up in tree proxies,while GGPA performs a greedy placement per segment in the whole tree. Simulation results show that ( 1) both HGPA and GGPA effectively reduce the server load and the cost of network access and are of better performance than the prefix placement algorithm; ( 2) GGPA has a slightly better performance but costs more time than HGPA; and ( 3) comprehensively speaking,HGPA is an ideal replication solution for tree proxies.

Topic Tracking Based on Spatiotemporal Contextual Model

Zhou Yi-peng Du Jun-ping

2012, 40(8):  82-87. 

Asbtract ( 319 )   PDF (427KB) ( 999 )  

Related Articles | Metrics

As the existing topic model can not accurately reflect the periodic variation and spatial distribution of topics in spatiotemporal context,a spatiotemporal contextual topic model for topic tracking is proposed according to the fact that the Internet information often contains the publishing time and site. In the investigation,first,by associating the distribution of subtopics with spatiotemporal context,a model is established to describe the cycle and strength of topics. Then,the parameters of the proposed model are estimated through EM algorithm,and are employed to obtain the snapshot and cycle of topics. Finally,the time-based topic similarity is calculated to estimate the subsequent topic information,thus realizing the topic tracking. The tracking experiments of food safety events indicate that,as compared with the traditional topic tracking method only depending on the text features,the proposed method can obviously improve the tracking efficiency of the topic as well as the tracking accuracy of subtopics. It is thus concluded that the proposed method helps to achieve more accurate topic retrieval.

Biological Engineering

Cloning,Expression and Hydrolysis Characteristics of Alkaline Protease Gene from Aspergillus oryzae

Ke Ye Chen Dan Li Jia-zhou Xie Ming-quan Luo Xiao-chun

2012, 40(8):  88-94. 

Asbtract ( 341 )   PDF (764KB) ( 988 )  

Related Articles | Metrics

Alkaline proteases from Aspergillus oryzae are of efficient hydrolysis ability and preferable debittering effect to plant protein. In order to obtain a large amount of alkaline proteases for industrial applications,the alkaline protease gene from A. oryzae was cloned by using RT-PCR technique,and was transformed into Pichia pastoris KM71 strain,thus being successfully expressed. Then,the protease was used in the hydrolysis experiments of bovine insulin B-chain,soy protein and peanut protein. The results show that ( 1) when the protease is induced to express in a 10-L fermentor,the protease activity of the fermentation broth is up to 4100U/mL; ( 2) the optimum pH value and temperature of the protease are respectively 8.5~9.5 and 50℃,and the protease is stable at a pH value of 6.0 to 10.0 below 40℃; ( 3) the protease is of extensive peptide-bond selectivity; and ( 4) the protease displays higher hydrolysis activity to soy and peanut protein than some commercial proteases. The above-mentioned results indicate that the recombinant protease is of potential application prospects.

Knockout of ptsGHI Gene of Bacillus amyloliquefaciens and Growth Characteristics of Corresponding Deficient Strain

Yang Hui-lin Wang Kun Liao Yu-ling Wang Bin Lin Ying Pan Li

2012, 40(8):  95-100. 

Asbtract ( 308 )   PDF (713KB) ( 1389 )  

Related Articles | Metrics

In the phosphotransferase system of Bacillus amyloliquefaciens,glucose is transported into the cell mainly through enzymes EI,HPr and EII^Glc encoded by the ptsGHI operon. In this investigation,first,about 1 kbp upstream and downstream DNA fragments of ptsG and ptsHI genes were amplified and were ligated into one fragment by using fusion PCR. Then,the fused fragment was inserted into the temperature-sensitive plasmid pKS2 and transformed by electroporation into Bacillus amyloliquefaciens XH7,thus constructing ptsG- and ptsHI-deficient strains. Experimental results show that ( 1) in LB medium,there is no obvious difference in the growth characteristics between the deficient strains and the wild-type strains; ( 2) in LB medium supplemented with 2% glucose,the ptsG gene-deficient strain shows a maximal cell density that is 28% higher than the wild-type one as well as a longer steady period than the control,while the ptsHI gene-deficient strain shows a maximal cell density that is about 32% lower than the wild-type one,and its growth accords well with that in LB medium; and ( 3) in guanosine fermentation experiments,the guanosine production yield of the ptsG gene-deficient strain is about 24% higher than that of the wild-type one,while that of the ptsHI gene-deficient strain is about 82% lower These results demonstrate that ptsG gene-deficient strains are of good ability in growth and guanosine biosynthesis.

Virtual Screening of Anti-Diabetes Active Components in Meroterpenoids from Psidium guajava Leaves

Liu Mei-feng Gu Ling-ling Jiang Li-rong Zhou Hui

2012, 40(8):  101-105. 

Asbtract ( 913 )   PDF (934KB) ( 1243 )  

Related Articles | Metrics

The meroterpenoids from Psidium guajava leaves may contain some components with high anti-diabetes activity because they possess high inhibitory activity to the anti-diabetes targets. In this investigation,by using PTPIB,PPARγ,PPARα,α-amylase and α-glycosidase as anti-diabetes targets and 13 dialdehyde meroterpenoid compounds as ligands,the molecular docking conditions between the ligands and the targets were analyzed,thus implementing the corresponding virtual screening. The results show that the meroterpenoids have docking sites with PTPIB,PPARγ and PPARα,but not with α-amylase and α-glycosidase; and that the weak non-covalent interactions,namely hydrophobic interaction,bonding and hydrogen bonding,all play an important role in the binding of ligands to proteins. In addition,Euglobal Iia,Euglobal Ib and Euglobal Ic firstly extracted from eucalyptus leaves have better affinity to PTPIB,PPARγ and PPARα,which provides some useful information for the design and structural modification of anti-diabetic drugs.

Local Alignment-Free Sequences Based on D2shepp Statistics

Liu Xue-mei Wen De-hua Yu Huang-zhong Gao Ya-ni

2012, 40(8):  106-109. 

Asbtract ( 298 )   PDF (411KB) ( 747 )  

Related Articles | Metrics

The similarities between two biological sequences is a major issue in computational biology,and a fast D2shepp statistics method based on the joint k-tuple content in two sequences has been used in the alignment-free sequence comparison. In this paper,two separate random sequences are generated based on the zero model,and their local alignment is conducted based on D2shepp statistics,thus obtaining the optimal values and the sum of these values. Then,the Power distribution is simulated and the distributions with different k values are analyzed. Finally,with the same parameters,the proposed local alignment is compared with the global alignment based on D2shepp statistics. It is found that the Power value of the proposed local alignment rapidly approaches 1 with the increase of the sequence length and that the proposed local alignment is quicker and more accurate than the global one.

Food Science & Technology

Effect of Pepsin Pretreatment on Hydrolysis Characteristics of Soy Protein

Zhao Mou-ming Zhang Yuan-hong Cui Chun Yuan Bo-en

2012, 40(8):  110-115. 

Asbtract ( 369 )   PDF (957KB) ( 1308 )  

Related Articles | Metrics

In order to improve the hydrolysis of soy protein,soy protein was prepared through alkali extraction and acid precipitation,and pepsin was applied to treat the soy protein for two hours to hydrolyze the glycinin. Then,alcalase and protamex were used to carry out further hydrolysis,and the molecular mass distribution of the corresponding products was determined by means of SDS-PAGE and GPC. The results show that ( 1) as compared with the single enzyme treatment without pepsin,pepsin pretreatment greatly improves the protein recovery,the degree of hydrolysis and the ORAC ( Oxygen Radical Absorbance Capacity) value of the hydrolysates,and the corresponding maximums are up to 95. 4%,23. 1% and 1078. 6,which are 39. 9%,35. 9% and 38. 5% higher,respectively; and ( 2) the molecular masses of the hydrolysates with pepsin pretreatment are mostly under 10 ku and mainly range from 1 to 5 ku. The above-mentioned results indicate that pepsin pretreatment can promote the hydrolysis of soy protein and enhance the antioxidant activity of the hydrolysates.

Effects of Heating on Tenderness，Texture and Microstructure of Sanhuang Chicken Breast Meat

Zhang Li-yan Wu Bing Bao Li-kun

2012, 40(8):  116-121. 

Asbtract ( 399 )   PDF (1137KB) ( 1302 )  

Related Articles | Metrics

By using some properties relevant to the meat quality as indexes,the effects of heating on those indexes and the corresponding variation trends were discussed. The results show that ( 1) the cooking loss of chicken breast meat significantly increases in a temperature range from 65℃ to 85℃ as well as in the initial 5~10min at 80℃; ( 2) a four-phase variation of the shear force value ( SFV) occurs with the increase of the heating temperature; ( 3) at 80℃,the SFV begins to increase after the chicken breast meat has been heated for 10min and is up to the maximum after a heating for 40min; ( 4) the variation trends of the TPA parameters of the chicken breast meat with the temperature and the duration are different from each other; ( 5) with the increase of temperature,the diameter of muscle fibres first decreases and reaches the minimum at 65 ℃,and then increases gradually; ( 6) at 75 ℃ and above,the endomysium and perimysium rupture,and the gap between the muscle fibres gradually becomes narrow,and at 95℃,the muscle fibres become compact; and ( 7) the variations of the above-mentioned properties become significant in a temperature range from 55℃to 85℃,and the synthetic variations of the muscle fibres and connective tissue at different temperatures greatly affect the cooking loss,the SFV and TPA parameters of the heated chicken breast meat.

Effect of Hydroxypropyl －β－Cyclodextrin Inclusion on Characteristics of d-Borneol

Su Jian-yu Chen Jian-ping Chen Ling Li Lin Zhu Liang Xu Zhen-bo

2012, 40(8):  122-127. 

Asbtract ( 382 )   PDF (638KB) ( 768 )  

Related Articles | Metrics

d-borneol /hydroxypropy-β-cyclodextrin ( HP-β-CD) inclusion complex was prepared through ultrasound method,and was confirmed by means of the differential scanning calorimetry ( DSC) and the X-ray diffractometry ( XRD) . Then,the volatility,thermal stability,anti-photodecomposition and phase solubility of the inclusion complex were tested with the d-borneol content as the index,which is determined via gas chromatography ( GC) . The results show that,under the influence of light and heat at the room temperature,the content of d-borneol in the inclusion complex is higher than that in the physical mixture of d-borneol and hydroxypropy-β-cyclodextrin,which indicates that the inclusion complex is of anti-photodissociation,thermal stability and a stability obviously superior to that of pure d-borneol,so it can be conveniently stored with the efficacy being preserved for a long time; and that the d-borneol concentration increases with the HP-β-CD concentration varying from 0 to 8mol /L,which means that the solubility of d-borneol is significantly improved after the inclusion.

Effect of Homogenization on Physical and Controlled Release Properties of Gelatin Emulsion Films

Yin Shou-wei Ma Wen Xu Hang Tang Chuan-he Yang Xiao-quan

2012, 40(8):  128-132,138. 

Asbtract ( 324 )   PDF (477KB) ( 1070 )  

Related Articles | Metrics

Protein-based films are of poor mechanical and water vapor-barrier properties. In order to solve this problem,a novel gelatin-olive oil emulsion film was prepared via the microfluidic emulsification technique. Then,the effects of homogenization on the particle size distributions of emulsions and the physical properties of the films were analyzed,and the correlations between the lipid droplet distributions and the mechanical as well as water vapor-barrier properties of the films were discussed. In addition,the controlled release properties of the films to lysozyme were also investigated. The results show that ( 1) when the emulsion is dispersed at a high rate,the lipid droplet is of large and unevenly-distributed particle size,and the corresponding film is of poor mechanical property,with a bi-layer-liked protein-lipid structure occurring during the forming of the film due to the enrichment of partial oil phase on the film surface; ( 2) when the emulsion is treated by means of microfluidization,it is in nano-scale with a concentrated particle distribution,and the corresponding film is of evenly-distributed oil phase and excellent tensile strength; ( 3) as compared with the control,the emulsion films obtained through the two above-mentioned homogenization techniques both have better water vapour-barrier property,although the corresponding mechanisms are different; and ( 4) the film prepared through microfluidization possesses excellent mechanical and water vaporbarrier properties as well as good controlled release ability to lysozyme.

Homogeneous Acetylation of Waxy Maize Starch in Ionic Liquid BMIMCL

Luo Zhi-gang Zhou Gang Zhou Zi-dan

2012, 40(8):  133-138. 

Asbtract ( 522 )   PDF (1135KB) ( 910 )  

Related Articles | Metrics

In this investigation,waxy maize starch acetates with high degree of substitution ( DS) were homogeneously synthesized without any catalyst,with ionic liquid 1-butyl-3-methylimidazolium ( BMIMCL) as the reaction medium. Then,the products were analyzed by means of FT-IR,¹H NMR,SEM,XRD and TGA.Experimental results indicate that ( 1) the maximum DS is up to 2.96 in optimal conditions,namely,an molar ratio of acetic anhydride to anhydroglucose units of 5 ∶ 1,a reaction temperature of 105℃ and a reaction time of 4 h; ( 2) the acetyl groups are introduced to the hydroxyl groups in starch products; ( 3) during the dissolution of the starch in the ionic liquid and the reaction with acetic anhydride,the crystalline structure of native starch is disrupted and a new structure forms; and ( 4) the thermal stability of starch acetates is better than that of the native starch and it increases with DS.

Effects of Locations of Biological Filter Added to Conventional Process on Water Supply

Lu Shao-ming Li Dong Hu Chang-hao

2012, 40(8):  139-145. 

Asbtract ( 306 )   PDF (756KB) ( 906 )  

Related Articles | Metrics

In this investigation,engineering cases and pilot-scale experiments were used to compare three kinds of processes with different locations of biological filters added to the conventional water supply process,namely,prepositioned biological filter ( HUBAF) ,mid-positioned biological filter ( UBACF) and post-positioned down-flow biological activated carbon filter ( DBACF) . The results show that ( 1) the three biological treatment processes all effectively improve the removal efficiency of organic matters; ( 2) DBACF generally removes NH₃-N with an efficiency of not more than 1.5 mg /L,but microorganism leak may occur in subtropical areas; ( 3) HUBAF is of a higher NH₃-N removal efficiency,but it has to suffer from the impacts of high turbidity,shellfish and algae in the raw water;and ( 4) UBACF possesses the advantages of both HUBAF and DBACF,so it is more suitable for new waterworks.

Treatment of Landfill Leachate via Fenton Oxidation Process Catalyzed by Fe²⁺ Loaded on GAC and Enhanced by Microwave

Ding Zhan Guan Wei-sheng

2012, 40(8):  146-152. 

Asbtract ( 515 )   PDF (759KB) ( 890 )  

Related Articles | Metrics

In this investigation,with the granular activated carbon ( GAC) loaded with Fe²⁺ as the catalyst,the microwave-enhanced Fenton reagent oxidation process was adopted to treat aged landfill leachate. Then,the COD and NH₃-N removals were taken as the indexes to analyze the influence of the Fe²⁺ loading amount,the GAC dosage,the microwave treatment time,the microwave power,the H₂O₂ dosage and the treatment solution’s pH value on the Fenton reagent oxidation. The corresponding microanalysis and kinetics were also carried out. The results indicate that ( 1) microwave can enhance the Fenton oxidation and promote the colloidal flocculation in the leachate;( 2) the COD removal is mainly due to the oxidation,while the NH₃-N removal is mainly due to the flocculation and adsorption; ( 3) the maximum COD and NH₃-N removals are respectively up to 93.01% and 85.76% in optimal conditions,namely,an Fe²⁺ loading amount of 33.32mg /g,a GAC dosage of 10 g /L,a microwave power of 720W,a microwave treatment time of 30min,a concentration of 30%H₂O₂ of 0.10mol /L and an initial pH value of 3; and ( 4) the characteristic peaks of the organic pollutants in the treated landfill leachate disappear or significantly weaken,which means that the proposed process is preferable. In addition,a kinetics model of microwaveenhanced Fenton reagent oxidation reaction is preliminarily established according to the experimental results.