Table of Content

25 October 2009, Volume 37 Issue 10

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Electronics, Communication & Automation Technology

Passivity-Based Control of Series Resonant Converter

Zhao Hong-ru Wang Xiao-fan Chert Yan-feng

2009, 37(10):  1-4. 

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In order to adjust the output voltage and eliminate the voltage ripple of the full-bridge series resonant converter, a passivity-based control method is employed to construct a new model of the converter and to control it. In the investigation, an Euler-Lagrange model of the converter is built, and a nonlinear passive controller is de- signed according to the concept that ＂damping injection makes the system stable＂ and Lyapunov stability theory. Simulated and experimental results show that, the response curves of both the output voltage and the inductance current jump with the random input disturbance and especially with the variable load parameter, then return to the equilibrium point; and that the controller is characterized by stable and adjustable output voltage, strong robustness, high speed, good tracking ability, and small voltage ripple.

Fundamental Frequency Transformation and Unpredictability Estimation Algorithm of Chaotic Systems

Jin Jian-xiu Qiu Shui-sheng Liu Yun-liang

2009, 37(10):  5-10. 

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In this paper, first, a method of fundamental frequency transformation for chaotic systems is proposed based on the concept of frequency domain analysis in the periodic orbit theory of chaotic attractors and on the matrix principle. Then, by using this method, Lorenz and Chua circuits are realized with different fundamental frequencies, and the corresponding frequency spectra are tested. Moreover, some experiments are carried out to verify the correctness of the proposed method, and an unpredictability estimation algorithm of chaotic systems is discussed. Finally, an improved formula for calculating the regression frequency is deduced. The proposed formula is also used to compare the unpredictability between Lorenz and Chua circuits with the same fundamental frequency of 3 kHz. The results indicate that the presented formula greatly improves the unpredictability estimation accuracy of different chaotic systems.

An Approach to Extracting Features of Movement-Related Potentials Based on Neighborhood Spatial Pattern

Liu Mei-chun Zhao Min Xie Sheng-li

2009, 37(10):  11-15. 

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In order to remedy the complex distribution of recorded electroencephalogram （EEG） data and the shortage of training data in terms of brain-computer interface （ BCI）, a novel approach named neighborhood spatial pattern （NSP） is proposed to extract movement-related potentials （MRPs）, which constitute the most important fea- tures utilized in the classification algorithms for the motor-imagery-based BCI. NSP searches the optimal direction which maximizes the ratio of the between-class distance to the within-class distance of the neighborhood in the pro- jected space. During the search, no assumptions about the latent data distribution should be made, and only the neighborhood relationship and the label information are required. NSP is also applied to two datasets from BCI com- petitions 2003 and 2001. The results show that NSP can effectively extract MPRs features.

Multiplex Transmission of Chirp Signals and Continuous Carrier Signals

Wen Rong-hui Sha Xue-jun Guo Pei

2009, 37(10):  16-19，24. 

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Based on the excellent energy concentration performance of cosine and Chirp signals in the frequency domain and the fractional Fourier transform （FrFT） domain, a communication system for frequency band reuse is designed. This system transmits multiplex BPSK signals respectively with cosine and Chirp signals as carriers within the same bandwidth, and performs the corresponding FrFY in the receiver to concentrate energies right around the peak of output. Moreover, the carrier signals in a narrowband are filtered in the FrFT domain, and are then demodulated in the time domain after an inverse FrFT. Simulated results show that the proposed system is of better antiinterference performance, as compared with the system only using cosine signals.

An Improved Resource Allocation Algorithm for MIMO-MC-CDMA Systems

Huang Yun-fei Pan Wei-qiang Chen Fang-fiong Wei Gang

2009, 37(10):  20-24. 

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Under the constraint of total transmission power at the sender, this paper proposes a resource allocation algorithm for MIMO-MC-CDMA systems. In this algorithm, the system throughput is optimized by assigning the power, the sub-bands and the code channels among users, and the bandwidth fairness is implemented by limiting the maximum and minimum occupied code channels of all users. The throughput maximization problem is modelled as a constrained optimizaiton problem, which is solved by the Lagrange multiplier method. Simulated results show that, as compared with the existing algorithms, the proposed algorithm significantly increases the throughput and accelerates the convergence.

Orthogonal Synthesis for Pattern of Linear Array Antenna with Constraints

Huang Long-yang Li Meng-xing Liu Hui Cheng En

2009, 37(10):  25-29. 

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Based on the orthogonal method for the antenna pattern synthesis of linear arrays, some constraint conditions are proposed to implement a constrained orthogonal synthesis. The proposed method simplifies the calculation due to the orthogonalization in unconstrained orthogonal approach, and it helps to realize the pattern synthesis of uniform or nonuniform linear arrays. Experimental results show that the proposed constrained orthogonal approach can fulfill the pattern synthesis of linear arrays with such constrains as beam steering in a given direction, null steering and sidelobe level suppression, and that it is of similar performance to that of the iterative computationbased adaptive synthesis method but with simple analytical calculation.

Effects of Imperfect Channel State Information on Performance of Multiuser-MIMO System

Liu Xue-fang Fu Feng-lin Lu Zhao-yang

2009, 37(10):  30-33. 

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In this paper, the impacts of such imperfect channel state information as the feedback delay and the channel estimation error on the performance of closed-loop multiuser-MIMO system based on antenna selection are analyzed, and the analytical expressions of both the outage capacity and the bit error rate are deduced. Moreover, the effect of muhiuser diversity on the system performance is revealed. Theoretical analyses show that the system performance degrades due to the feedback delay and the estimation error. Numerical simulations indicate that the theoretical analyses are valid and reasonable.

A QoS-Guaranteeing Algorithm for WiMAX Mesh Network

Huang Zhao-wen Feng Sui-li Ye Wu Zhuang Hong-cheng

2009, 37(10):  34-38，43. 

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In this paper, several existing QoS （Quality of Service） -guaranteeing mechanisms for WiMAX mesh network （WMN） are analyzed, and the limitations of the existing mechanisms relating to the routing algorithms and the per-hop QoS guarantee are pointed out. Moreover, the reasons for the difficulty in guaranteeing the QoS are dis- cussed, and an effective and dynamic QoS-guaranteeing algorithm for WMN is proposed. In this algorithm, WMN is considered as an integer to determine some constraints for the data packet processing of each WMN node in a view of integrity, and the traffic-handling algorithm for each node is presented. By using the proposed algorithm, the throughput of WMN is significantly improved and the fairness of bandwidth sharing by nodes is well guaranteed. Simulated results on a self-developed WMN platform show that the proposed algorithm is both effective and flexible.

Sub-Pixel Edge Detection Method Based on Sigmoid Function Fitting

Zhang Wu-jie Li Di Ye Feng

2009, 37(10):  39-43. 

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Sub-pixel edge detection is an effective way to improve the accuracy of edge detection using image processing algorithms. In this paper, the principles, advantages and shortcomings of such existing sub-pixel edge detection algorithms as the moment method, the fitting and the interpolation methods are analyzed, and a novel sub- pixel edge location algorithm is proposed based on the Sigmoid function fitting. This algorithm employs the Sigmoid function to obtain an edge model and uses the image edge gray data to perform a nonlinear least-square fitting for the edge model. Thus, the sub-pixel location of image edge is obtained. Theoretical analyses and experimental results demonstrate that the precision of the proposed algorithm based on Sigmoid function fitting achieves 0. 045 pixel, and the detection rate increases by one order of magnitude as compared with that of the gray moment method, and by two orders of magnitude as compared with those of the spatial moment, the Zemike moment and the interpolation methods. Thus, it well satisfies the requirements for strong stability, high precision and strong real-time performance in image measurement.

Selection Algorithms of Key Reference Pictures for AVS-M Based on Rate-Distortion Optimization

Zhang Qing-ming Peng Qiang Dai Zhi-gang

2009, 37(10):  44-48，65. 

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The error resilience of AVS-M can not achieve desirable results because the adopted error control technology is too simple. In order to solve this problem, the end-to-end error propagation distortion in AVS-M video encoding and transmission is investigated at a precision level of pixel, and a non-feedback key reference picture selection （KRPS） algorithm is realized, based on the rate-distortion optimization model which combines the general transmission distortion estimation model with the rate-distortion optimization （RDO） rule. Then, a feedback KRPS algorithm is proposed based on the non-feedback KRPS. Experimental results indicate that the adopted distortion estimation model can accurately estimate the end-to-end distortion, and that, as compared with the algorithm of AVS-M, the non-feedback and the feedback KRPS algorithms respectively result in the Y-PSNR gains of 1.9 -6. 4dB and 2. 7 ～ 10. 9dB, at a packet loss rate varying from 3% to 20%. It is thus concluded that the two proposed algorithms effectively improve the performance of error resilience in AVS-M video encoding.

Stability Analysis and Control for Uncertain Switched System with Input Delays

Wang Xin-mei Pei Hai-long Wei Wu

2009, 37(10):  49-54. 

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This paper deals with the robust stability and control of a class of uncertain switched systems with both constant delays and time-varying delays. Based on the reduction method, the Lyapunov stability theory and the linear matrix inequality （LMI） theory, a state feedback controller and a switch strategy are designed, and the sufficient conditions for the system stabilization are determined. Then, a simulation is performed and the effectiveness of the proposed method is verified. It is also proved that the controller based on the reduction method stabilizes more systems than the existing memoryless controllers in the case of a degenerate model.

Strip Shape Prediction and Optimization Based on Chaotic Optimized Support Vector Machine

Chen Zhi-ming Huang Xiao-hong Luo Fei Xu Yu-ge

2009, 37(10):  55-59. 

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This paper deals with the strip shape control in hot continuous rolling and proposes a shape prediction and optimization algorithm based on a chaotic optimized support vector machine model. In the investigation, first, an improved multi-scale chaotic optimization algorithm combined with the real-coded genetic algorithm is proposed to optimize the parameters of the least-square support vector machine model. Then, the model is trained using some on-line data and is used to predict the flatness value of strip steel. Moreover, the control parameters among the in- put parameters of the model are optimized to improve the shape control. Simulated results show that, as compared with the BP neural network, the proposed algorithm is more effective in predicting the flatness and improving the accuracy of shape control in hot continuous rolling, with a flatness value optimized by 40%.

Design of Non-Fragile H∞ Filter for Time-Delay Jump Systems

Chen Miao Wang Dao-bo Wang Zhi-sheng

2009, 37(10):  60-65. 

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In this paper, the robust non-fragile H∞ filtering is investigated for a class of uncertain stochastic Itotype time-delay system with Markov jump parameters, and a Markov jump filter is designed to guarantee the mean square stability of robust stochastic exponential of the closed-loop filter error system with uncertain controlled objects and filters, and to keep the disturbance attenuation level below a given upper bound. Moreover, by considering the additive perturbations of controlled objects and filters, the solvability condition for the existence of robust non-fragile filter is derived in the form of linear matrix inequality （LMI） and generalized Ito formula. The effectiveness of the proposed approach is then verified using a numerical example, and the superiority of the designed non-fragile filter is finally demonstrated through comparison.

Computer Science & Technology

A Structured P2P Overlay Network with Small-World Characteristics

Wei Wen-hong Xiao Wen-jun

2009, 37(10):  66-72. 

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As the existing P2P overlay networks can not closely connect peers with the same interest together, it is not practical to provide browsing service in such systems. In order to solve this problem, the existing cube-connected cycle （CCC） graph is generalized, and the topological properties of the generalized CCC （GCCC） graph are in- vestigated. Afterwards, a novel structured P2P overlay network marked as GCNET （Generalized Cube-Connected Cycle network） is defined based on GCCC, which possesses better small-world characteristics and stronger robust- ness than other P2P overlay networks. Simulated results show that GCNET can reach the theoretical lower bounds of both the routing table size and the query path length.

A QoS-Based Approach to Data Access

Pang Xiong-wen Bao Su-su Li Dong

2009, 37(10):  73-78. 

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The data access on grid is of low quality because the existing query optimization techniques do not consider the dynamic properties of data resources in grid environments. In order to solve this problem, a QoS （ Quality of Service） -based approach to data access is proposed, which considers not only the dynamic properties of data resources but also the QoS goals of users, and selects generated query plans according to the QoS goals of users. Mo- reover, a segmented pipe tree based on the pipelined parallelism is presented to optimize multi-join queries, which not only improves the parallelism but also returns some results to users as soon as possible. Experimental results show that the proposed approach is effective in providing data access at different levels for different users.

A Routing Scheme Based on Awareness of Node Motion Scope

Liu Yao Wang Jian-xin

2009, 37(10):  79-83. 

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As the traditional routing protocols can not adapt to the intermittent connection of mobile networks due to the sparse distribution, frequent disruption or periodical motion of nodes, a new routing protocol marked as MSAR is proposed based on the awareness of node motion scope with the uncertainty of network status. Instead of being supported by geographical-position locating devices, the proposed protocol uses encounter histories to analyze the motion scope of nodes and chooses nodes with small overlapped motion scope to forward messages. Simulation resuits indicate that MSAR guarantees higher message delivery ratio and relative lower average delay, and that it greatly decreases the number of message copies distributed in the network and reduces the network overhead.

Simulation and Analysis of Router Buffer Requirements in High Bandwidth-Delay Networks

Wang Jian-xin Li Chun-quan Huang Jia-wei

2009, 37(10):  84-88,94. 

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In order to meet the requirement for router buffer size in high bandwidth-delay networks, five typical buffer-sizing methods based on the TCP model are analyzed via the NS2 simulation, and the effects of various highspeed TCP protocols and active queue management （AQM） mechanisms on the buffer-sizing methods in high bandwidth-delay networks are discussed in detail. Simulated results show that ： （ 1 ） the buffer-sizing methods based on different assumptions adapt to different network environments; （2） the validity of the existing cache mechanisms depends on the ratio of the bandwidth-delay product to the flow number; and （3） when high-speed TCP protocols and AQM mechanisms are used in high bandwidth-delay networks, the buffer size is greatly reduced.

A Label Aggregation Algorithm for MPLS Multicast Based on Similar Tree

Li Ling-zhi Zhu Yan-qin Yang Zhe

2009, 37(10):  89-94. 

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In this paper, a similar tree-based algorithm is proposed to reduce the label space of muhicast in multiprotocol label switching （MPLS） networks. The proposed algorithm aggregates the labels of multicast groups that are similar to the same common tree. In this algorithm, common trees are created via fuzzy clustering, based on which multicast trees are built and group members are updated. The change of dynamic multicast memberships can only give rise to the type conversion of label edge router （LER） nodes, without redistributing labels for the groups. Test results indicate that the proposed algorithm greatly reduces the quantity of MPLS labels being used, and that, when the number of A element is greater than half of the maximum and when the similarity threshold equals 0. 75, more than 50% of the multicast groups can be aggregated, with an average waste of less than 0. 50 nodes in each group.

A Model of Alternate Service Based on System Load

Wang Wen-feng Zhao Yue-long

2009, 37(10):  95-100，107. 

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In order to improve the availability and quality of service （QoS） of existing cluster systems, a model of alternate service based on the system load is proposed by introducing a dynamic k-ray tree architecture. In this model, an auto-regressive load prediction model, a multi-machine heartbeat mechanism based on the election domain partition, and a leader election mechanism and algorithm in the dynamic domain are all employed. Theoretical analyses and experimental results demonstrate that the proposed model greatly improves the reliability and availability of cluster systems and saves the average response time cost and the election overhead. Thus, it well satisfies the requirements for high availability and QoS of large-scale Cluster services.

Automatic Estimation Algorithm Mixture Model Based on of Component Number of Penalized Distance

Zhang Da-ming Fu Mao-sheng Guo Hui Luo Bin

2009, 37(10):  101-107. 

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The expectation-maximization （EM） algorithm is a popular approach to the parameter estimation of the finite mixture model （FMM）. A drawback of this approach is that the number of components of the FMM is not known in advance. In this paper, a penalized minimum matching distance-guided EM algorithm is discussed. Then, under the framework of Greedy EM, an automatic algorithm with high speed and accuracy is proposed to esti- mate the component number of the Gaussian mixture model. The effectiveness of the proposed algorithm is finally verified by the simulations of univariate and bivariate Gaussian mixture models.

Food Science & Technology

Antioxidant Properties of Sugarcane Extracts

Michael Saska Chung Chi Chou

2009, 37(10):  108-111. 

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Dietary antioxidants help to protect tissues and cells against the harmful effects of free radicals. At present, numerous preparations extracted from natural sources are available to the public as dietary supplements. In this paper, four sugarcane-based products and one corn liquor-based product on the USA market are selected and characterized by their composition and antioxidant capacity. It is found that the antioxidant capacity of the five products correlates very well with their color. Sugarcane juice clarified with two different proce- dures and concentrated under vacuum are then analyzed in terms of antioxidant capacity. The results show that neither the lime nor the soda ash clarification measurably reduces the antioxidant capacity. The effects of different separation methods for colorants on the antioxidant capacity are finally analyzed.

Effect of Micro-Fluidization Treatment on Conformational and Functional Properties of Kidney Bean （Phaseolus vulgaris L. ） Protein Isolates

Yin Shou-wei Tang Chuan-he Wen Qi-biao Yang Xiao-quan

2009, 37(10):  112-116，123. 

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A high-pressure micro-fluidization homogenizer for nano-sized products was used to treat the solution of kidney bean （ Phaseolus vulgaris L. ） protein isolate （KPI）. The effects of micro-fluidization treatment at different pressures on the conformational and functional properties of KPI were then investigated by means of solubility and turbidimetric measurements, DSC, fluorescence spectroscopy, UV spectroscopy and Far-UV circular dichroism （CD） spectroscopy. The results indicate that the micro-fluidization treatment leads to the transformation of insolu- ble aggregates into soluble ones, thus improving the solubility （PS） and the emulsifying activity index （EAI） of KPI. It is also found from the fluorescence emission spectra and the Far-UV CD spectrum that micro-fluidization treatment has no obvious effect on the tertiary and secondary structures of the proteins. Moreover, according to the DSC results, the thermal stability and structure orderliness of KPI show no obvious change after the micro-flui- dization treatment.

Separation and Identification of Volatile Flavor Compounds in High-Salt Liquid State-Fermented Soy Sauce

Gao Xian-li Zhao Mou-ming Cui Chun Cao Ming-kai Li Dan

2009, 37(10):  117-123. 

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In this paper, such technologies as solid-phase micro-extraction （SPME）, simultaneous steam distil- lation-extraction （VSDE） and direct solvent extraction （DSE） were employed to separate and concentrate the volatile flavor compounds in high-salt liquid state-fermented soy sauce, and the extracts were identified by means of gas chromatography-mass spectrometry （GC-MS）. 147 flavor compounds, including 17 kinds of acids, 12 kinds of alcohols, 16 kinds of aldehydes, 36 kinds of esters, 12 kinds of furan（one）s, 13 kinds of ketones, 14 kinds of heterocyclic compounds, 8 kinds of phenols, 6 kinds of pyran（one） s, 4 kinds of pyrazines, 3 kinds of pyrrol（ idon）es and 6 kinds of sulfur-containing compounds, were then identified. The results indicate that, in the dominant volatile flavor compounds in the soy sauce, namely, esters, acids, alcohols, aldehydes and heterocyclic compounds, esters are of the most species and of the highest relative content ; and that 16 aroma-impact compounds of Japanese and Korean soy sauces were detected from Chinese high-sah liquid state-fermented soy sauce.

Effects of Ultrafiltration on Characteristics of Enzymatic Hydrolysates of Pinctada martensii Protein

Zhao Mou-ming Xiao Ru-wu Cui Chun Zhang Chao-hua

2009, 37(10):  124-128,139. 

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The distribution of relative molecular mass （RMM） of peptides and the composition of amino acids in the enzymatic hydrolysates of Pinctada martensii protein before and after an uhrafihration treatment were investigated by means of gel filtration chromatography and high-performance liquid chromatography. Then, the variation of permea- tion flux and sensory characteristics during the ultra：filtration process were analyzed, and the selectivity and separa- tion efficiency of uhrafihration membrane were evaluated. The results show that （1） the permeation flux gradually decreases with the prolonging of ultrafihration time; （2） after the ultrafihration, the delicious flavor of permeation fraction significantly improves, and the fishy odor and the bitter taste almost disappear; （3） the permeation fraction mainly comprises peptides with the RMM of less than 4500; （4） peptides with the RMM of more than 5000 can also pass through the membrane with a relative molecular mass cut-off of 5 000; （5） the real relative molecular mass cut-off of the uhrafihration membrane is within the range of 7000 -8000 approximately; and （6） after the ultrafiltration treatment, the proportion of delicious amino acids to the total amino acids in the permeation fraction increases, while those of both bitter and hydrophobic amino acids decrease.

Separation of Active Components from Cassia tora L. Using High-Speed Countercurrent Chromatography

Zhang Yun-feng Wei Dong Guo Si-yuan Liang Shi-zhong

2009, 37(10):  129-134. 

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In order to effectively separate high-purity active components from Cassia tora L. , a high-speed countercurrent chromatography （HSCCC） procedure was performed to separate five monomers from the acetic ether extraction of the plant. The procedure was performed in a two-phase solvent system at a flow rate of 2.0mL/min. The stationary phase is the upper phase of n-hexane-ethyl acetate-ethanol-water （in a volume ratio of 5： 3： 6： 6）. The gradient elution of mobile phase is from the lower phase of n-hexane-ethyl acetate-ethanol-water （in a volume ratio of 5 ： 3： 6： 6） to the lower phase of n-hexane-ethyl acetate-ethanol-water （ in a volume ratio of 5： 3： 5： 7 ）. According to the physicochemical properties and the spectral data of MS, 1HNMR and ^13CNMR, the five separated components were identified as aurantio-obtusin （ Ⅰ ）, chryso-obtusin （Ⅱ）, obtusin （Ⅲ）, physcion （Ⅳ） and emodin （ Ⅴ ）. Moreover, 90. 42, 45.39, 31.84, 121.71 and 39. 10 mg of the five components were respectively separated from 500mg of crude extract, with the purities of 97.4%, 93.0%, 94. 8%, 96.3% and 95.5% and the recoveries of 91.5%, 96.7%, 93.3%, 95.6% and 98.4%, respectively.

Environment Science & Technology

Corrosion Behaviors of Q235 Steel in Seawater Containing Sulfate-Reducing Bacteria

Yang Zhi-quan Zhou Shao-qi Liu Guang-zhou Lin Curt-guo

2009, 37(10):  135-139. 

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In order to better reveal the mechanism of microbiological corrosion, the corrosion behaviors of mild steel Q235 in marine conditions with/without sulfate-seducing bacteria （SRB） were investigated via such electrochemical methods as the corrosion potential, the polarization curve, the electrochemical impedance spectrometry and the en- vironmental scanning electron microscopy. The results show that （ 1 ） due to the existence of SRB, the corrosion potential of Q235 steel in marine conditions rapidly shifts to the passive potential region until it is gradually stabilized at a value of about - 740 mV ; （2） in the marine condition with SRB, both th.e corrosion current density and the corrosion rate increase, while the polarization resistance becomes lower; and （3） after the microbiological corrosion, there forms a large amount of holes on the surface of Q235 steel, which shows the occurrence of heavy pitting corrosion.

Treatment of Dyeing Effluent by Coupling Ultrasonic Field with Aerated Bio-Packing Tower

Zou Hua-sheng Yan Xiao-man Li Min-le

2009, 37(10):  140-144. 

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A continuous ultrasonic reactor coupling with an aerated bio-packing tower was adopted to treat the firstorder dyeing effluent, and the removals of chemical oxygen demand （CODcr） and ehroma with different combined technologies were then analyzed and compared. The results show that the combined technology of biotreatment- （ ultrasonic ＋ active carbon） -biotreatment is most effective in the treatment of dyeing effluent, and that, after being sequentially processed with a biological treatment for 7 h, an ultrasonic ＋ active carbon treatment combining four ultrasonic frequencies of 60, 80, 100 and 125 kHz for 2h, and a biological re-treatment for 20h, the effluent with an initial CODcr of 600 - 1000 mg/L and an initial chroma of 320 meets the first-grade discharge standard of GB 4287-- 1992, with a COOcr removal of about 90% and a chroma removal of about 95%

Investigation into Start-Up of Integrated Two-Phase Anaerobic Reactor Treating Piggery Wastewater

Pu Yue-wu Guo Mei-jun Liu Zu-an

2009, 37(10):  145-149. 

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An integrated two-phase anaerobic reactor was designed to treat piggery wastewater, and the corresponding start-up process was investigated. In this investigation, the volumetric loading rate （VLR） of the system was raised by alternately increasing the influent COD （ Chemical Oxygen Demand） concentration and decreasing the hydraulic retention time （HRT） at 37℃. Moreover, acidogenic and methanogenic phases were separated by controlling the VLR in combination with adjusting the pH value of the influent. The results show that （ 1 ） after a 68-day operation, a COD removal of 20. 00% - 301 00% in the acidogenic phase and a COD removal of more than 80. 00% in the whole system are respectively achieved at a VLR of 8.84kg/（m³· d） and a HRT of 20.95h; （2） the acidogenic phase is operated up to a VLR of 31.11 kg/（ m³·d） with a HRT of 5.95 h whereas the methanogenic phase is loaded up to a VLR of 9.39 kg/（ m³ ·d） with a HRT of 15 h ; （ 3 ） the suspended solid （SS） in the effluent is of a content of less than 400 mg/L and a highest removal up to 92.80% ; and （4） the volumetric produc- tion rate of biogas reaches 2. 57m3/（ m³· d）.

Determination of Pulping Effluent COD Using Derivative Spectrophotometry- Chemometrics Method

Chen Hong-lei Chen Yuan-cai Zhan Huai-yu Fu Shi-yu

2009, 37(10):  150-154. 

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In order to simplify the determination of chemical oxygen demand （COD） of pulping effluent using the conventional methods, a high-speed derivative spectrophotometry-chemometrics method is proposed. In this method, based on the mathematical relationship between the multi-wavelength derivative spectral signals and the known COD values of a set of pulping effluent samples, a calibration model is established using a chemometrics software. With this model, the COD value of a certain pulping effluent can be easily predicted according to the multi-wavelength derivative spectral signals. The proposed method provides a new and convenient approach to the high-accuracy COD determination of pulping effluent without using any chemical reagents.