Table of Content

25 March 2005, Volume 33 Issue 3

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Preparation and Properties of La-doped BaTiO₃ Ceramics(Ⅱ)：By a Surface-Coating Technique of Metal-Organic Compound

Zhuang Zhi-qiang Wang Yue-hui Liu Bo Wang Xin

2005, 33(3):  1-4. 

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In order to satisfy the need for thin layer of dielectric ceramics with small-size grains and high dielectric constant in MLCCs applications,the surface-coating technique was utilized to modify hydrothermal-synthesized BaTiO₃(BT)with La-organic compound as the precursor,which was coated on the powders uniformly.It is found from experiments that the organic component completely decomposes at 650 ℃ and a single-phase solid solution
(Ba_(1-x) La_2x/3 )TiO₃ forms after sintering.It is also found that,with the increase in La content,the peak of tempera-ture-dependence of dielectric constant of La-doped Si-BT ceramics is compressed and moves to a low-temperature region,that the average Curie temperature t_av decreases linearly with La content, and that the grain size and dielec-tric properties of the ceramics are greatly influenced by the increasing rate of sintering temperature.

Structures and Properties of Na₂O-BaO-AI₂O₃-P₂O₅ Glass

Deng Zai-de Sun Jia-sen Yin Bing Yang Gang-feng Chen Dong-dan

2005, 33(3):  5-8. 

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In phosphate ass composed of 16.7Na₂O•27.8BaO•xAl₂O₃•(55.5-x )P₂O₅( x=0,2.8,5.6,8.4,11.1.in mole)and doped with Nd₂ O₃，the relationships between the Al₂O₃content and the characteristics-density,molar volume,refractive index,transition temperature T_g ,softening temperature T_f,thermal expansion index and chemical stability-were studied.The structure of the glass was also investigated by means of infrared spectral analy-sis.Th e results show that,with the increase in Al₂O₃content,the density,refractive index,T_g and T_f of the glass increase,and the chemical stability gradually increases,while the molar volume and therm al expansion index de-crease.Th is indicates that,in phosphate glass,increased Al₂O₃content strengthens the network,thus improving the physical-chemical properties of the glass. Infrared spectral analyses show that the variation of the absorption peak of P-O-Al band is consistent with the improvement of the glass properties.

Compisition Dependence of Spectroscopic Properties of Yb³⁺-Er³⁺Co-ped Borophosphate Glass

Xie Zhi-ying De Zai-de yang Gang-feng Sun Jia-sen

2005, 33(3):  9-12,27. 

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The effects of B₂O₃ content and different modifiers (alkali metals and alkaline earth oxides)on the spectroscopic properties of Yb³⁺-Er³⁺co-doped B₂O₃-P₂O₅-MO-R₂O-AI₂O₃(M=Zn,Ca,Sr,Ba;R=Li,Na,K)system were respectively analyzed.Th e results indicate that,with the increase in B₂O₃ content,the radiation lifetime increases,while the spontaneous emission probability,the absorption cross-section,the corresponding integral absorption cross-section and emission cross-section all decrease,that the refraction index reaches its minimum when the mole fraction of B₂O₃ is 15%, and also that the absorption cross-section and the emission cross-section increase with the electric field intensity of the modifier cation.

Activity and Influence Factor of Double-Bond Hydrogenation of NBR Catalyzed by Hydrogen-Storage Alloy

Liu Sa Jia De-min

2005, 33(3):  13-18. 

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The selective hydrogenation of carbon-carbon double bonds in acrylonitrile-butadiene rubber (NBR) so-lution was investigated,with the intermetallic hydrides forming from hydrogen-storage alloys LaNi₅,LaNi_4.8Cu_0.2 and MlNi₅ (CoMnAl)_x as catalysts and hydrogen sources.NBR and the hydrogenated acrylonitrile-butadiene rubber (HNBR)were then analyzed by means of IR, ¹HNMR and iodometric analysis.In addition,the surface morpholo-gY and composition of the alloys were analyzed with SEM ,etc.The results demonstrate that,without any surface treatment, LaNi₅ and LaNi₅ Cu_0.2 can catalyze the hydrogenation of NBR,while the hydrogenation degree of HNBR catalyzed by MlNi_5-x(CoMnAl)_x is naught,that surface treatment hardly influences the catalytic activity of LaNi₅,but seriously influences that of MlNi_5-x(CoMnAl)_x ,that the hydrogenation degree of NBR achieves 14.7% after proper surface treatment to MlNi_5-x(CoMnAl)_x  (such as immersing in KOH and KBH₄ solutions and so on),and that the addition of metals such as Pd and Pt can enhance the activity of the alloys for hydrogenation,with the hv-drogenation degrees of HNBR respectively achieving 22.0% and 18.7%.

Temporal-Spatial Distribution of Pile Temperature of Aerated Static Bin Composting System

Zhu Neng-wu

2005, 33(3):  19-23. 

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Four pilot swine manure composting experiments were conducted to investigate the temporal-spatial dis-tribution of pile temperature of aerated static bin composting system during the composting of swine manure.The re-suits are as follows:(1)the pile temperature undergoes three phases(heating,thermophilic and cooling phases),and the duration of the thermophilic phase is long enough to conform to the sanitary standard of the non-hazardous treatment of nightsoil;(2)the pile structure can be improved by adding rice straw in sawdust,and the increasing rate of temperature is more significantly enhanced than that with sawdust,thus benefiting the temperature increasing process and the composting process;(3)when corn corb is used,the thermophilic phase with the temperature be-ing controlled at 70℃ is prolonged compared with that at 60 ℃ which would postpone the maturity of composts;(4)the distribution of pile temperature presents gradient effect,that is,the temperature in the under layer is higher than that in the upper layer in the initial phase,while it is opposite after entering the therm ophilic phase.

Characterization of Solution Casting Film of PMMA

2005, 33(3):  24-27. 

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The acetone solution casting films of poly(methylmethacrylate)under natural evaporation and ultrasonic vibration were respectively characterized by DSC(Differential Scanning Calorimetry)and PyGC-MS(Pyrolysis Gas Chromatography-Mass Spectroscopy).Analytical results indicate that the condensed structure of the polymer and the residue solvent in the films are both different in different film-forming conditions,and that the residue solvated acetone in the film prepared under natural evaporation is twelve times that under ultrasonic vibration.

Preparation of TiO₂ Photocatalytic Coatings

Wang Hui Zeng Ling-ke Huang Lang-huan Ren Xue-tan Cheng Xiao-su Zhang Ming

2005, 33(3):  28-30. 

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Modmed fine TiO₂ powders were prepared by doping La₂O₃ via the sol-gel process.TiO₂ photoc atalytic coafing was then prepared on a slide substrate,with ethyl silicate as the binder.The influences of some factors ,such as TiO₂,content(mass fraction,the same below),active carbon and zeolite,on the photocatalytic activity of the coating were discussed.The results show that the coating is of most excellent photocatalytic activity when the
TiO₂,content is 70%.that active carbon an d zeolite can improve the photocatalytic activity,and that active carbon has a greater enhancement on the photocatalytic activity,with an optimum addition of 10%(mass fraction)·

Denoising of Texture Images Based on Wavelet Packet Decomposition

Zhang Guang-xin Cui Yang Zhou Ze-kui

2005, 33(3):  31-33,49. 

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Noise greatly affects the post-processing of images. General denoising methods can remove the noise of images with gentle change,but have a poor effectiveness on the denoising of texture images with many details.In this paper,according to the different characteristics that signal and noise exhibit during the wavelet decomposition,a novel denoising algorithm based on the wavelet packet decomposition is presented.In this algorithm,texture ima-sub-band are obtained.Thus,signals and noise can be discriminated based on the norms,and the texture images can be denoised.Experimental resuits indicate that the proposed algorithm is of excellent performance in denoising leather images,and can remove most noise of texture images with well-kept texture inform ation.

A Linearization Approach to Blind Separation of Convolution Mixture Signals

Xiao Ming Xie Sheng-li Fu Yu-li

2005, 33(3):  34-39. 

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The blind separation of convolution mixture signals is a nodus in blind source separation.In this paper,aiming at the independently and identically distributed non-Gaussian signals, a novel approach to the blind decon.volution is presented,namely,the Two-Step Extraction.The first step is to eliminate the delay vectors of all sources and to extract only linear mixture signal vectors.Thus,the problem of convolution is transformed into the linear
one.This step is called convolution linearization.The second step is to separate the estimated linearized signals and to obtain the source signals.Moreover,a method to design the filter of convolution linearization is proved by using the statistic and the matrix theories. The practicability of the proposed method is finally demonstrated by simula-tion.

Rapid Adaptive Allocation Strategy in Multiuser OFDM System

Ke Feng Ye Wu Feng Sui-li Gong Han-dong

2005, 33(3):  40-43. 

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The application of adaptive technology to the muhiuser OFDM (Orthogonal Frequency Division Multiplexing)system can increase the spectrum usage,reduce the transmission power of the system and optimize the system performance.In this paper.a mathematical model f0r the adaptive bit and power allocation in the muhiuser OFDM system in frequency selective fading channels is proposed,and a rapid sub-optimal adaptive allocation algorithm is presented.According to the estimation of instantaneous channel characteristics,the adaptive allocation algorithm can assign the subchannels and bits for each user in the system to minimize the total transmission power with a given bit error rate.Simulated results show that the proposed algorithm is simple in calculation,high in eficiency and optimal in theory as the optimal scheme.

Arbitrary Shaped ROI Image Coding Based on HVS

Liang Ya-ling Yang Chun-ling Yu Ying-lin Du Ming-hui

2005, 33(3):  44-49. 

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The application of Set Partitioning in Hierarchical Trees(SPIHT)to the image coding of arbitrarily shaped Region of Interest(ROI)is investigated.In this investigation,according to the characteristics of SPIHT algorithm and by considering the properties of the image wavelet coefficients when the coefficients associated with ROI are scaled up,an improved algorithm based on Human Visual System(HVS)is proposed.This algorithm possesses
the merits of the generic-scaling-based method and the maxshifi method,that is,it can adjust the relative importance between ROI and the background,and can be used for the coding of arbitrarily shaped ROI.Th e results show that the proposed method is of better subjective visual quality than the maxshifi method.Moreover,theoretical ana-lyses and simulated experiments all indicate that the proposed method is better than the Visual Object(VO)coding prescribed in MPEG-4 .

Metamodeling of Pattern Semantic Link and Its Applications

Yin Jian-fei Guo He-qing PeRg Xin-yi

2005, 33(3):  50-54. 

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The coarse-grained model transformation is an important technical requirement on the Model-Driven Software Development(MDSD)scene.It is not enough to meet this requirement only by defining the general model transformation languages.One of the reasons is that the general model transform ation langu ages work at the level of metamodels of specific modeling langu ages,but not at the level of general design intentions.In this paper,a PSL
(Pattern Semantic Link)metamodelling method is proposed.The heavyweight extension of the UML(Unified Mo-design intentions.UML Action Semantics and the metamodel inheritance are then used to realize the automatic pattern generation and transform ation.The proposed method can efectively support the coarse-grained model transform ation at the level of general design intentions.

A Novel ZVS Single-Stage PFC Converter

Zhou Zhi-qiang Cai Li-juan Yan Yi-zhi

2005, 33(3):  55-59. 

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In order to increase the efficiency and reduce the electro-magnetic interference of single-stage PFC con-verter,the conventional Boost PFC converter was combined with the asymmetrical half-bridge DC/DC converter,thus forming a novel ZVS single-stage PFC converter by means of cascading integration technique.A prototype Was then produced to verify the efectiveness of the converter.The experimental results show that the proposed converter is of the advantages of simple topology,simple control and low cost.It can achieve hiSh PF,and,at the same time,achieve ZVS for all power switches.

Investigation into I-v Characteristics of Single-Benzene Molecular Device by M eans of Tight-Binding M ethod

Li Na Cai Min

2005, 33(3):  60-62. 

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The Tight-Binding Method is adopted to investigate the I-V characteristics of a three-terminal singlebenzene molecular device.with the results well reflecting the electrical characteristics of MOS(Metal-Oxide-Semiconductor)devices.The influence of temperature on the I-V characteristics of the device is also simulated and discussed.it is found that the current magnitude increases with the increase in the gate voltage,and that temperature greatly afects the current magnitude,which lays a theoretical basis for the development of molecular devices and nano-devices.

Protocol Verification of ITS Dedicated Short-Range Comm unication

Tu Yu Xu Jian-min Zhong Hui-ling

2005, 33(3):  63-68. 

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Aiming at the complexity of DSRC(Dedicated Short-Range Communication)protocol,the fuzziness and ambiguousness resulted from the natural langu age of the protocol.the protocol engineering method is adop-ted to guarantee the integrality,correctness,security,portability and standardization of the protocol, The SDL (Specification and Description Language)is chosen to get the formal description of the protocol,On this basis,the corresponding verification procedure and realization method are proposed, which are then used to validate the protocol SDL model.Th e results demonstrate that the proposed protocol is logically corect.

Application of Improved Hybrid Genetic Algorithm to Optimized Design of Architecture Structures

Zhang Yan-nian Liu Jian-ping Liu Bin Zhu Chao-yan Li Yi

2005, 33(3):  69-72,82. 

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In the iterative process of the standard genetic algorithm (SGA)，there often appear premature conver-gence,oscillation,over-randomization and low iterative speed.To solve these problems. some improved measures including transgenic operator and one-parent genetic operator are proposed.and a three-equal-partition algorithm (TEPA)fbr the structural optimization with discrete variables is provided.This algorithm is then combined with genetic algorithm(GA)in the process of primal colony forming and colony evolving.Thus,the two algorithms inde-pendently operate,mutually harmonize and jointly play their roles.Moreover,on the basis of practical structure de-signs in engineering,a model of structural optimization with discrete variables is established bv sufficienflv consi.dering the constraint conditions stipulated by the BODTI and the demands f0r various engineering standards. The opti-mized results obtained by different algorithms show that the improved hybrid genetic algorithm is of the advantages of saving time,high efficiency. good local searching ab ility and excellent global convergence property.

Cathode Design in Electrochemical Machining of Blades Based on Conductivity Mathematical Model in Machining Gap

Li Zhi-yong Zhu Di

2005, 33(3):  73-77. 

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The effect of liquid field is very important to the cathode design in electrochemical machining. In this paper,based on the liquid field characteristics,a practicable mathematical model of the conductivity change in li-quid direction was established by considering the efects of temperature increasing,gas rate and pressure of the machining gap on the conductivity.Th is model was then used to design the tool cathode.Moreover,the gap distribu-tion based on the proposed model was compared with that based on the electric field only,with the conclusion that the cathode shape design ed with the proposed conductivity model more fits the workpiece shape and accords more with the actual physical process of electrochemical machining.

Corrosion Mechanism of Alkali Chloride During the Incineration of Refuse

Zhu Jian-zhong Chen Lie-qiang Can Ge

2005, 33(3):  78-82. 

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With the development of solid waste incineration technology,more and more attentions were paid to the high-temperature corrosion behavior.In this paper,according to the general high-temperature corosion characteris-tics of solid waste during the incineration,corosion tests of stainless steel were performed in a complicated solid-vapour-gas environment,the corosion dynamics was discussed,and the corosion mechanism caused by alkali chlo-tides was analyzed.The results indicate that the corosion process during the incineration is a complicated process with a muhi-stage corosion dynamics curve.The analytical resuhs of corosion mechanism show that alkali chlo-tides can accelerate the corosion of stainless steel.and that stainless steel is of the ability of anti.corosion at a high temperature.which makes it usable in the incinerator of solid waste at a temperature below 600℃ .

Mathematical Simulation of the Rising Rate of Dispersed Phase Droplets in Static Aqueous Two-Phase System

Hu song-qing Li Lin Chen Ling Guo Si-yuan Cai Miao-yan

2005, 33(3):  83-86,94. 

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First,the constant-speed stage during the phase separation of aqueous two-phase system in static circumstance was properly hypothesized,and the framework of the rising rate model for dispersed phase droplets was estab-lished via mechanical analytical method.Next.the density difference between the bottom and the top phases,the viscosity and the phase ratio of two phases of 11 different PEG/phosphate aqueous two-phase systems were determined.Then,according to the volume variation of the dispersed phase measured by experiments,the rising rates of dispersed phase droplets in different systems were obtained.The model parameters were finally decided by means of the system identification.Thus,a mathematical model of the maximum rising rate of dispersed phase droplets during the phase separation of aqueous two-phase system was established.

Mensuration of Chitinase-Producing Abilities of Strains Isolated From Digestion Guts and Farming Water of Hafiotis Diversicolor Supertexta

Wang Zhi Cai Jun-peng Wen Qi-biao

2005, 33(3):  87-90. 

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The chitinase-producing abilities of strains isolated from both farming water and digestion guts of Haliotis diversicolor supertexta were studied by a special TCBS(Thiosufate-Citrate-Bile Salts-Sucrose)and by screening the culture media.The resuhs indicate that there are chitinase-producing strains in farming water and digestion gu ts of the abalone.12 bacteria were isolated from abalone digestion gu ts.which account for 34.3%of the total bacterial populations in the guts.Species identification shows that these chitinase-producing strains belong to Vibrio fluvialis and Vibrio minicus.From the ab alone farming water,4 chitinase-producing strains were isolated,which account for 1 1.8% of the total bacterial populations.These 4 strains belong to Vibrio fluvialis.Compared with the farming wa-ter,it is clear that there are more chitinase-producing strains in abalone digestion gu ts,and abalone digestion gu ts display selectivity toward the chitinase-producing strains.

Coupling of Liposome Phosphatide and Antibody Protein

Guo Di Pan Li Han Lu Zhang Bao-ning

2005, 33(3):  91-94. 

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In order to easily make proteins,such as antibodies,cross-link on the surface of liposome and control the covered area on the surface,a simple and controllable preparation of immunized liposome was,presented.In the course of preparation,linear-chain aldehyde with certain proportion was added into the mixture of phosphatidylch-line and cholesterol,and a reverse-phase evaporation technique was adopted to produce liposomes.The results indi-cate that the hydrophilic aldehyde groups arranged in the bilayer lipid molecules expose to the aqueous phase and react with the amino groups in the antibody molecules,forming Schif base,that the covering area can be changed by changing the amount of aldehyde,and that the activity of the liposome is greatly improved.

Optimal Investment Problem Under M inimum Return C0Ilstraint

He Chun-xiong Luo Jun Tu Yu-qing Jiao Jian

2005, 33(3):  95-98,102. 

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Based on the B lack-Scholes op tion p ricing theory, the equivalent martingale measure is constructed to obtain the op timal strategy of an op timal investment problem. This problem is under the constraint that the return is not less than the maximum of the market return ( random return) and the constant guaranteed return. Meanwhile, by the analysis of the characteristics of this investment problem with HARA utility function, it is concluded that this investment strategy can be simp lified as an unconstrained op timal investment strategy and a hedge strategy based on the European put-op tion and the two-asset exchange option.

Application of Two Binomial Tree M odel to the Pricing of Convertible Bond

Yang Li-hong Yang Xia

2005, 33(3):  99-102. 

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Convertible bond is a new hybrid financial tool, which possesses the characteristics of bond and option and the performances of financing and evading risk. The investigation into the p ricing of convertible bonds is very important to both issuers and investors in p ractice or theory. In this paper, by using the Two Binomial TreeModel and considering the call and put items, the p ricing theory and corresponding p ricing model of convertible bonds is systematically studied through 24 kinds of convertible bonds in China market. The results show that the convertible bonds are significantly underp riced.