Table of Content

20 October 2004, Volume 32 Issue 10

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FC -72 Flowing Boiling Heat Transfer Enhancement on the Chip Surface with Microfin



Zhang Zheng- guo, Yu Zhao- sheng, Fang Xiao- ming, et al

2004, 32(10):  1-5. 

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To improve the cooling efficiency of the chip by using the high-efficiency heat transfer technology and ensure the normal operation of the chip, the flow and boiling heat transfer characteristics of four kinds of chips with the microfin surfaces immersed in saturated FC-72 were investigated, with the microfin dimensions (thickness ×height) of 50 μm ×190μm, 50μm ×250 μm, 100 μm ×150 μm and 100 μm ×300 μm, respectively.The effect of FC-72 subcooling on the boilingheat transfer was also investigated, with the results compared to those of a chip withsmooth surface.The experimental results show that, with the increasing of FC-72 subcooling, the critical heat flux (CHF) increases for all the tested chips.For chips with microfin surfaces, the wall temperature corresponding to the CHF is less than 85 ℃, while for those with smooth surfaces, it is more than 85 ℃.It is also shown that, with the same FC-72 subcooling, the maximum allowable heat flux for chips with microfin surfaces are 7～ 9 times that of those with smooth surfaces, which proves that the microfin can obviously enhance the boiling heat transfer of FC-72.


Theoretical Sound-insulation Model of the Polymer/Inorganic Particle Composites



Liang Ji- zhao Jiang Xing- hua

2004, 32(10):  6-9. 

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 The sound insulation behaviors of the inorganic particle-filled polymer composites were analyzed by means of the acoustics theory with the purpose of revealing the sound insulation mechanisms of the composites．Based on the analysis, a relevant mathematical model was then established, and the sound insulation properties of the glass beadfilled polyethylene composite were finally predicted．The results indicate that there is a linear relationship between the capacity of sound insulation and the volume fraction of glass beads, and the capacity is significantly sensitive to the sound frequency．It is also indicated that with a constant volume fraction of glass beads, the capacity of sound insulation decreases with the increase of the bead size．The principal cause for the improvement of sound insulation property lies in the behaviors of reflection, scattering and refraction which occur under the condition of sound wave contacting the particles．


Structure and Mechanical Property of the Magnesium Alloy Prepared by the Equal-channel Angular Pressing via Different Processing Routes



Liu Yin, Chen Wei- pin, Zhang Da- tong, et al

2004, 32(10):  10-14. 

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In order to investigate the effect of different processing routes for the equa-l channel angular pressing （ECAP） on the microstructure and property of magnesium alloy, AZ31Mg alloy was prepared by means of ECAP in the die, with an intersecting angle （φ） of 120°and four processing routes of A, BA, BC, C, respectively．The microstructure and property of the pressed material at room temperature were then measured and analyzed．The results indicate that, compared with those pressed via A, BA, C routes, the workpiece pressed via BC route can be pressed with more passes and has a greater deformation．It is also indicated that, after a mult-i pass pressing, the grains of the alloy are significantly fined and the mechanical property improves greatly, and different routes have various effects on the microstructure and property．With a pressing pass number of12, the materials pressed via BC and BA routes are of a greatly improved ductility and a significantly lowered yield strength, while for those pressed via A and C routes, the ductility improves slightly with little change in the yield strength.


Microtopography and Microstructure Characteristics of the Carbon Steel Surface Machined with High-speed Turning



Xu Jin Ye Bang- yan

2004, 32(10):  15-19. 

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 Based on the experimental observations of the high-speed turning for medium carbon steel‚the forming courses and characteristics of the microtopography and microstructure of the workpiece surface were analyzed．The re-sults show that the cutting speed and material hardness are the main factors affecting the material deformation in the high-speed cutting process‚and the cutting heat makes the material in the cutting zone soften as well as causes particu-lar furrows and side flow on the workpiece surface．It is also shown that there exist a second quenching and tempering due to the high cutting temperature‚thus causing the change of the micro-hardness and the appearance of a hard and fragile white-layer contexture on the workpiece surface．The motion between the cutting tool and the workpiece‚along with the cutting heat greatly affects the formation of the machined surface profile‚that is‚with the increasing of cutting parameters‚the cutting heat and the friction heat increase‚thus forming the particular microtopography and microstruc-ture of the workpiece surface machined with high-speed turning．


Determination of Some Important Parameters in the Stamping -necking Process of the Cone Type for Cylindrical -tube Workpiece



Niu Wei- zhong

2004, 32(10):  20-23. 

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 In order to provide technologists with some guidelines for process -planning and die-designing‚the stamping-necking process of the cone type for thin-walled cylindrica- l tube workpiece was analyzed．Then‚based on the thickness -changeable axisymmetric plastic thin-shell theory and the assumption that the workpiece material is perfectly rigid-plastic‚the variation law and distribution patterns of the stress in the necking deformation zone with different cone-angles and Coulombʾs coefficients of friction were formulated by means of data fitting．Many formulas were finally deduced for determining the maximum stress and the necking force during the necking-forming stage‚the final thickness‚the arc-surface curvature ra-dius‚the needed tube-blank length as well as the minimum necking coefficient of the workpiece．These formulas can be eas-ily applied to the analyses of the cylindrica- l tube workpieces produced with deformation-hardening material。


Prediction of the Workpiece Accuracy During the Electrochemical Machining Based on BP Neural Network



Sun Chun- hua Zhu Di Li Zhi- yong

2004, 32(10):  24-27. 

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 In order to correctly predict the workpiece accuracy during the electrochemical machining（ECM）‚the method of BP neural network was used to establish a prediction model．Feature parameters of the BP neural network model were determined by analyzing the main factors affecting the machined accuracy‚and the dimensional numbers of the input layer and the middle hidden layer were confirmed according to the practical conditions‚thus obtaining the model structure which was then trained by using the experimental results．Finally‚a BP neural network model to pre-dict the accuracy of the workpiece during the ECM was established．The prediction results show that the error of accu-racy prediction can be controlled within10％ by using the proposed model‚which is of excellent capability of accuracy prediction．


Optimized Design of the Chilled Water-conveying Pipeline in the District Cooling System



Liu Jin- ping Du Yian- guo Chen Zhi- qin

2004, 32(10):  28-31,35. 

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The transaction model constitution and the transmission congestion management in the process of power transactions constitute a key issue in the normal operation of the power market．In this paper‚by drawing on some o-verseas experiences an according to the specific conditions of Chinaʾs reform of the power market at its earlier stage‚a new transaction model and transmission congestion management method was proposed based on the investigation into the power market in Guangdong Province．In the congestion management‚the corresponding least reduction of social benefit is taken into account and the cost of the congestion management is distributed in accordance with the load con-gestion dispatching factor．A numerical example was finally presented to prove the validity of the proposed method‚which is of practical significance to the development of the power market‚especially to the construction of electric net -works．


A New Transaction Model and Transmission Congestion Management Method for the Power Market



Wu Guo- yue, Jiang Jin- liang, Wu Guo- pei, et al

2004, 32(10):  32-35. 

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The transaction model constitution and the transmission congestion management in the process of power transactions constitute a key issue in the normal operation of the power market．In this paper‚by drawing on some o-verseas experiences and according to the specific conditions of Chinaʾs reform of the power market at its earlier stage‚a new transaction model and transmission congestion management method was proposed based on the investigation into the power market in Guangdong Province．In the congestion management‚the corresponding least reduction of social benefit is taken into account and the cost of the congestion management is distributed in accordance with the load con-gestion dispatching factor．A numerical example was finally presented to prove the validity of the proposed method‚which is of practical significance to the development of the power market‚especially to the construction of electric net -works．


Delay-dependent Robust Stability of Uncertain Systems with Multiple Time -delays and Nonlinear Perturbations



Ma Xin- jun Xu Bu- gong

2004, 32(10):  36-40. 

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A new robust stability criterion for uncertain systems with multiple state-delays and nonlinear time-varying perturbations is obtained by the matrix inequality technique．In these systems‚the delays are unknown constant‚the time-varying parameter uncertainties are norm-bounded and the nonlinear perturbations meet certain linear constraints．Then‚on the basis of matrix inequality technique and Lyapunov functional‚a delay-dependent robust stability criterion expressed as LMI （Linear Matrix Inequality） is established．It is finally shown by two examples that‚compared with the methods presented in the literatures‚the method presented in this paper can reduce the conservativeness of the results‚which indicates the validity of the proposed method.


Number of the Separation Matrixes in the Linear Nonsingular Mixture of Blind Signals



Xiao Ming Xie Sheng-li

2004, 32(10):  41-45. 

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 In order to investigate the reason for different separation matrixes of different algorithms in the linear non-singular mixture of blind signals‚a theoretical result is proved for the modified model of blind signal separation（BSS）： if we only take into account the rotating factors while ignoring the linear proportion zoom factors‚then the ex-act number of the separation matrixes is the factorial of the source number．A new algorithm to get the separation ma-trixes is then proposed．In this algorithm‚the separation matrixes are obtained by solving some quadratic nonlinear e-quations‚and the algebraic theory and second-order statistic method are adopted．Meanwhile‚a method to get the sepa-ration matrixes by means of the matrix transform is also introduced in the paper．The simulation results have verified the correctness of the theoretical result．


Optimization of the Dynamic Zoning for Elevator Traffic Based on the Artificial Immune Algorithm



Li Zhong- hua, Mao Zong- yuan, Zheng Ri- rong, et al

2004, 32(10):  46-50. 

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A newly developed artificial immune algorithm was proposed and employed to optimize the dynamic zoning for vertical elevator traffic‚thus implementing the optimization calculation of the elevator traffic for non-continuous floors．In this paper‚the dynamic zoning model of elevator traffic was clearly outlined‚and the artificial immune algo-rithm for the dynamic zoning model was designed．It was then simulated by comparison among different distributions of elevator traffic flow．The simulation results demonstrate that the dynamic zoning based on AIS is of excellent per-formance in handling uneven rea- l time up-peak traffic flow．The proposed algorithm can be utilized to rapidly search the optimal or sub-optimal zoning of elevator traffic and is of considerable practical value．

Application of Fuzzy Relations to the Software System Testing



Yang Jin- tao Guo He- qing

2004, 32(10):  51-55. 

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The concepts of system place-state （PS） and anticipative PS were firstly proposed based on the application of the black box technology to the system testing of distributed software．As the test case controls the system PS and a fuzzy occurs between the system PS and the anticipative PS‚the fuzzy implication logic was next used to study the sys-tem testing．It was then concluded that the action relation of the test case to the anticipative PS was a fuzzy control re-lation and that the degree of control depended on the quality of software．The standard value of the tested software to pass the test was then obtained from the fuzzy control relation and fuzzy inference rules‚thus quantifying the judgment for software to pass the test．Quantified pass-rules in the system testing were finally put forward and applied to improve the automatic testing tool‚by which the efficiency of the test improved and the test cost was reduced．


A Trust-based Peer-to-peer Single Sign -on Scheme Between Web -based Applications



Lin Man- shan, Guo He- qing, Yin Jian- fei, et al

2004, 32(10):  56-61. 

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 In order to solve the problem of single point failure in the traditional central single sign-on （SSO） schemeand accommodate to the dynamic and broad SSO across organizations‚a trust -based peer -to-peer SSO scheme （P2P-SSO） between Web-based applications was proposed based on the Liberty protocol．In this scheme‚by introducing theconcept of peer -to-peer into SSO‚it is possible to dynamically control the boundary of SSO across organizations．Thecorresponding identity federation process and the SSO process were then put forward by establishing a SSO trust scheme‚and the problems such as the user information exchange strategy‚authorization administration‚etc．in the SSO across organization scenario were finally solved．The analytical results indicate that the traditional central SSO scheme is adaptable to the SSO within an organization and the P2P-SSO scheme to the SSO across organizations‚while for practical applications‚the combination of the two schemes is more adaptive.


Management Information System of Urban Bridges Based on the B/S Mode



Fu Xin- sha Wang Yan- jun Jia De- Liang

2004, 32(10):  62-66. 

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 The Guangzhou Municipal Bridge Management Information System based on the B／S mode was introduced in this paper‚in terms of the exploitation goals‚the general design of the system and the function of the system mod-ules （including the Geographic Information System Module‚the Database Management Module‚the Net -level Manage-ment Module and the Project -level Management Module）．The key technologies and methods to implement the system were described by comparison‚with their advantages and disadvantages as well as the applicability clearly pointed out．Meanwhile‚a proper technical scheme was proposed according to the actual conditions．


Field Test for the Resilient Modulus of Existing Cement Concrete Pavement with Impact Compaction



Su Wei- guo Lu Hui Li Lin- sheng

2004, 32(10):  67-70,75. 

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 In order to evaluate the bearing capacity of the existing cement concrete pavement with impact compaction and recommend input parameters for the design of overlay pavement structure‚it is necessary to conduct field test for the resilient modulus of the compacted pavement．In this paper‚the principle and applicability of the bearing plate test was discussed based on the analysis of the problems existing in the deflection measurement and the evaluation of the existing cement concrete pavement with impact compaction and cracking-seating．Then‚by analyzing abundant testing data of the bearing plate‚the magnitude range and the variation of the resilient modulus for the existing cement con-crete slabs and its base course with impact compaction were obtained．The analytical results can be used to evaluate the remaining bearing capacity of the pavements and can also be used as input parameters for the design of the overlay pavement structure．The mechanical efficiency of the impact compaction technology in the treatment of the existing ce-ment concrete pavement was finally demonstrated．


Design Principle of the Concrete Structure with Glass Fiber-reinforced Polymer



Luo Yi Zheng Le- yi Li Ji- tao

2004, 32(10):  71-75. 

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In this paper, by considering the mechanics of materials and the design theory of the steel concrete structure, a revised design theory of bending resistance and shear resistance for the concrete structure reinforced with GFRP was proposed, with the assumption that the concrete was firstly damaged and a modification factor was introduced. Thus, the mechanism and characteristics of the brittleness damage for the concrete structure reinforced with GFRP were obtained. A design example of a shearing wall structure reinforced with GFRP was finally presented which primarily verifies the practicability, objectivity and security of the revised design theory.

Cloning and Homology Analysis of the Conservative Sequence of Phytoene Synthase Gene from Dunaliella Salina



Jiang Jian- guo Yan Yuan Song Dong- lin

2004, 32(10):  76-79. 

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In this paper, according to the cDNA conservative sequence of Psy from two species of microalgae (Dunaliella bardawil and Haematococcus pluvialis) and the amino acid sequences of Psy from six species of plants (Arabidopsis thaliana, Oryza sative, Tagetes erecta, Lycopersicon esculentum, Capsicum annuum and Daucus carota) , the forward primer, namely, 5'-ACGCCAAGACCTTCTA-3', and the reverse primer, namely, 5'-GTTGTCATAGTCATTCTTCTC-3' were designed. The amplification by using D.salina genomic DNA as the temple was then performed with an annealing temperature reduction of 0.5 ℃ per cycle in 46～35 ℃, thus obtaining a amplified fragments of about (2 490 bp, ) which was finally identified as partial fragment of the Psy gene from D.salina by the homology analysis of NCBI/BlastP.

Relationship Between the Substitution Degree and the Anticoagulation Activity of Cellulose Sulfate Sodium



Wang Zhao- mei, Li Lin, Hu Song- qing, et al

2004, 32(10):  80-84. 

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 Cellulose sulfate sodium （Na-CS MC ） is of excellent anticoagulation activity．In order to study the structure-activity relationship between the anticoagulation activity and the substitution degree （ D S ） of Na-CS MC ‚a chemical stock of Na-CS MC analogues with different D S values must be established．In this paper‚Na-CS MC samples with differ-ent D S values and the same relative molecular mass were obtained by means of acid hydrolysis and chromatography separation．The effect of the substitution degree of Na-CS MC on the anticoagulation activity and the inhibition of coagu-lation factors was also investigated．The results indicate that both the prolongation of activated partial thrombo-plastin time and thrombin time and the inhibition to the two anticoagulation factors （Ⅱaand Xa） caused by Na-CS MC improve with the increasing of D S value within a certain range．


Mathematical Simulation for the Synthesis Process of Ethyl Tert-butyl Ether by Means of Reactive Distillation



Yuan Hong Yang Bo- lun

2004, 32(10):  85-89. 

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 In view of its great prospects for application and the peculiarity as well as complexity in its application‚the reactive distillation process was mathematically simulated and a general mathematical model was constructed‚with the synthesis of ethyl tert -butyl ether （ETBE） as an example．The Partial Newtonʾs method was then adopted to seek solu-tion for the proposed model．It is found through experiments that the experiment results basically accord with the simu-lation results‚thus proving the rationality and usability of the proposed model．The main technical conditions of the ETBE synthesis by means of the reactive distillation were finally optimized by using the proposed model．It is thus concluded that there exist some optimal values of the conditions；the optimal number of the total plates is16；the opti -mal mole fraction of the ethanol feed is0．5；and the optimal flowrate of the feed is0．24×10－3 mol／s．It is also con-cluded that the azeotropy of the reaction system exerts a negative impact on the reactive distillation process．The pre-sent study may offer some guidelines for the optimization of ETBE synthesis by means of the reactive distillation pro-cess．


Application of the Path Sampling to the Model Selection by Means of Bayesian Method



Hao Zhi- feng Wang Ning- ning

2004, 32(10):  90-92. 

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 Bayesian factor|model selection|path sampling|Box-Cox model

A New Clustering Method Based on Fuzzy c-mean Algorithm and the Genetic Algorithm



Guo Hai- xiang Zhu Ke- jun

2004, 32(10):  93-96. 

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 In order to get the optimal clustering number and the corresponding samples in each cluster‚a new cluster-ing method is introduced in this paper．The new method can be used to construct an object evaluation function‚which takes into consideration not only the scattering degree among clusters but also the compactness in the same cluster．To obtain the center and memberships values of each cluster by iteration‚the FCM（Fuzzy c-mean） algorithm is adopted．The genetic algorithm is then used to search for the global optimal point．The proposed algorithm is applied to the fuzzy clustering of the ful- l factored productivity of China．