Archive

15 January 2011, Volume 32 Issue 1 Previous Issue    Next Issue
---
OriginalPaper


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

OriginalPaper

Select

Scheduling of walking beam reheating furnaces based on ant colony optimization algorithm Tu, Nai-Wei (1); Luo, Xiao-Chuan (1); Chai, Tian-You (2) 2011, 32 (1):  1-4+9.  DOI: - Abstract ( 308 )   HTML   PDF (1592KB) ( 642 )   To solve the scheduling problem of walking beam reheating furnaces with the energy consumption and productivity of hot rolling mills taken into account, a mathematical model was developed for the mixed charging of cold and hot slabs. The objectives were to minimize the practical heating time, waiting time for heated slabs during hot rolling and the number of the mixed chargings. An ant colony optimization (ACO) algorithm was therefore designed to solve the model, which was embedded in the local search process based on neighbourhood search, thus improving the convergence rate. Results of the simulation in according to actual production data of an iron/steel plant showed the effectiveness of both the model and algorithm proposed. References | Related Articles | Metrics

Select

Generalized projective synchronization based on T-S fuzzy model for time-delaying chaotic systems Chen, Zhao-Na (1); Ma, Chi (2); Zhao, Wen-Dong (2); Fu, Yong (2) 2011, 32 (1):  5-9.  DOI: - Abstract ( 302 )   HTML   PDF (1321KB) ( 713 )   Based on the Tagaki-Sugeno (T-S) fuzzy model, a control scheme of the generalized projective synchronization was proposed for chaotic systems, with a new fuzzy-state observer designed in terms of linear matrix inequalities. Thus, the generalized projective synchronization of chaotic systems was regarded as the design of a fuzzy-state observer. According to the Lyapunov stability theory, it was verified that the proposed scheme is feasible and globally stable. Changing the scale factor of generalized projective synchronization, the chaotic signal output in any proportion to the chaotic primary driving system is obtained. The numerical simulation results verified further that the proposed scheme is available to implement the projective synchronization of the Lorenz chaotic system. The scheme is simple in design and available to be extended to other chaotic systems. References | Related Articles | Metrics

Select

Weighted least squares reconstruction algorithm for positron emission tomography Teng, Yue-Yang (1); Zhang, Tie (1) 2011, 32 (1):  10-13.  DOI: - Abstract ( 279 )   HTML   PDF (1443KB) ( 683 )   An iterative reconstruction algorithm was developed based on the weighted least squares cost function for positron emission tomography. Unlike the conventional gradient-based algorithm, this algorithm made use of an auxiliary function in the current iterative point to form iteration process, by which the optimal solution was given instead of that by objective function, thus giving the new iterative points. Furthermore, the algorithm automatically satisfied the non-negative constraints of pixels without step size factor required, then ensuring the monotonous decreasing of objective function with global convergence provided. The results of the experiments based on both simulative and real clinical data showed that although the proposed algorithm requires the operating time that is much the same to the SA-WLS and ML-EM, it has higher convergence rate and better imaging quality than the latter. References | Related Articles | Metrics

Select

Guaranteed cost control for networked congestion systems with parameter uncertainties Zhai, Ding (1); Wang, Hui-Min (1); Liu, Guo-Yi (1); Liang, Li (2) 2011, 32 (1):  14-17.  DOI: - Abstract ( 281 )   HTML   PDF (1217KB) ( 580 )   Based on the existing control model for network congestion, a class of networked system with time-varying parameter uncertainties is considered with the aim of dealing with the problem of prevalent parameter uncertainties. Linearizing a previously developed nonlinear dynamic model of TCP, a linear time-varying system with parameter uncertainties is obtained to represent the intrinsic nonlinear characteristic more accurately. Then, applying the Lyapunov stability theory and linear matrix inequalities (LMIs) approach to this linear model, a convex stability condition is obtained and, simultaneously, a guaranteed cost controller design method is proposed to solve the problem of congestion control. The theoretical analysis and simulation results showed that the method proposed can guarantee some given performance indices in addition to the better robustness and faster convergence than some others. References | Related Articles | Metrics

Select

A 4-D dynamic real-time rendering method for cardiac image Feng, Chao-Lu (1); Yang, Jin-Zhu (1); Zhao, Da-Zhe (1); Liu, Ji-Ren (2) 2011, 32 (1):  18-21.  DOI: - Abstract ( 372 )   HTML   PDF (1461KB) ( 625 )   The heartbeat timeline information can be acquired by MDCT (multi-detector computed tomography) via ECG (electro-cardio-gram) gating process, but conventional CPU-based volume rendering methods cannot meet the requirement of dynamic cardiac real-time reconstruction. A GPU-based texture mapping method is therefore proposed to achieve it by introducing the ECG gating process with MDCT to acquire multi-groups cardiac volume data, where each of them is called a time-phased data and mapped onto a GPU texture unit step for step. Material and illumination properties color and opacity of transfer function computed by GPU are separately mapped onto another two GPU texture units. Then, textures are looked up via fragment programs to implement the resultant image. According to time interval during data acquisition, volumetric data textures are switched over time to get a beating heart. Experimental result showed that the method proposed can reconstruct a dynamic cardiac real-time rendering, where image quality of it is good enough to meet clinical requirements. References | Related Articles | Metrics

Select

A declarative parallelism based program parallel optimization framework on multicore platforms Yang, Chun-Yang (1); Duan, Bo-Bo (1); Yuan, Huai (1); Liu, Ji-Ren (1) 2011, 32 (1):  22-26.  DOI: - Abstract ( 274 )   HTML   PDF (930KB) ( 614 )   To satisfy the requirements for exploiting various types of available parallelism in destination programs on multicore platforms fully and efficiently, an extended TStreams model was developed by introducing the hierarchical relationship, equivalent relationship and characteristic weights as the support, so as to implement a declarative parallelism based feature aware parallel optimization framework (FAPOF) which is on the basis of the model. FAPOF supports multi-aspects and multi-grains description for the latent parallelism and appropriate optimization rules available in destination algorithms. With users' description, FAPOF can evaluate the different combinations of the optimization decisions in a compiler-driven method, thus the destination programs can be optimized in parallel semi-automatically. In this way, the programmers' complex and difficult ″decision-making″ jobs in parallel optimization will be transformed into an easier ″description″ job for available parallelism. Test results showed that the method mentioned above can reduce the difficulty in parallel optimization significantly with the optimization efficiency improved. References | Related Articles | Metrics

Select

Automatic centerline extraction based on tubular feature for coronary arteries Wang, Sheng-Jun (1); Fu, Ling (2); Kang, Yan (2); Liu, Ji-Ren (1) 2011, 32 (1):  27-31.  DOI: - Abstract ( 344 )   HTML   PDF (1731KB) ( 1331 )   To solve the problem of improper centerline extraction due to the improper segmentation of coronary arteries and obviously changed vessel curvature, an algorithm based on tubular structure was proposed for the automatic centerline extraction of coronary arteries. The coronary artery centerline was extracted roughly on the basis of the configuration of the skeleton nodes, and then the criteria were proposed for the three kinds of blood vessel structures according to the tubular structure of coronary so as to detect the actualities of the improper segmentation of coronary arteries. As a result, the disconnected centerline was regulated and joined on the basis of local vascular structure, thus obtaining the complete and connective centerline of coronary arteries. The experimental results of coronary CTA volume data indicated that the proposed algorithm is able to solve well the problem of improper centerline extraction due to improper segmentation of coronary arteries and obviously changed vessel curvature, with high robustness provided. References | Related Articles | Metrics

Select

High-accuracy OFDM channel estimation algorithm for OFDM systems Wang, Jin-Kuan (1); Wang, Xu (1); Xu, Peng (1) 2011, 32 (1):  32-35.  DOI: - Abstract ( 312 )   HTML   PDF (1262KB) ( 686 )   To decrease the BER (bit error ratio) of MMSE (minimum mean square error) channel estimation algorithm for OFDM systems, an improved channel estimation algorithm by using band-stop filter is proposed. In the proposed algorithm, the initial estimate value of channel is given by MMSE. Then, the noise is separated from channel frequency response by use of the characteristics of DFT (discrete Fourier transform). Finally, the channel estimation algorithm is filtered by the band-stop filter so as to improve the system accuracy of BER performance. Simulation results showed that the performance of the proposed channel estimation algorithm is obviously better than classical MMSE channel estimation algorithm on condition that the pilot frequency interval remains unchanged or increases gradually, though the computational complexity is increased slightly. References | Related Articles | Metrics

Select

On the net separation of a wireless mobile sensor network Li, Da-Zhou (1); Zhao, Hai (1); Zhu, Jian (1); Zhang, Kuan (1) 2011, 32 (1):  36-39.  DOI: - Abstract ( 254 )   HTML   PDF (860KB) ( 499 )   Because of the autonomous mobile sensor nodes which make the network unavailable to sustain stable connectivity, permanently, wireless mobile sensor network is separated into many local subnets persistently. Based on the in-depth study on the dynamic separation of the network, the reasons why the net separation has to be done are analyzed in view of physics and links. Defining the net separating time ratio, degree of net separation and loading rate of network, the net separation is discussed quantitatively. Lots of simulative data revealed that there are two features of the net separation, i.e., the net separating time ratio is inversely proportional to the number of nodes and the loading rate is directly proportional to the stability of the degree of net separation. The results of the study will provide a reference for not only the application of wireless mobile sensor networks but also the study on upper layer protocols. References | Related Articles | Metrics

Select

Combination scheme of active and passive topology reconfiguration for ad hoc networks Ye, Ning (1); Zhu, Zhi-Liang (2); Liu, Jun (1) 2011, 32 (1):  40-43.  DOI: - Abstract ( 317 )   HTML   PDF (1328KB) ( 750 )   Based on the correlation between performance and topology in a large-scale heterogeneous ad hoc network, a cluster-based topology reconfiguration algorithm was proposed. For the active reconfiguration, the densely deployed nodes within every cluster will discover local topology by acquiring adjacent information to maintain the k-connectivity of neighboring topology so as to implement it. While the intercluster boundary nodes and relevant links will form the weighted bipartite graphs via computation, and they are matched optimally with each other to maintain the k nonadjacent links, where k is the number of paths selected and its value shall be adjusted dynamically according to the characteristics of local topology and requirements for applications. The passive reconfiguration is applied to the network failure by way of recovering the diffusive connectivity in the neighborhood around the failure where k hops are to be implemented. Then, after recovery, the failure domain is optimized topologically and locally. Simulation results showed that the active topology reconfiguration scheme in combination with the passive one can improve the invulnerability, reliability and validity of networks. References | Related Articles | Metrics

Select

Research on the dynamic allocation algorithm of shared cache for multi-core processor Zhou, Ben-Hai (1); Qiao, Jian-Zhong (1); Lin, Shu-Kuan (1) 2011, 32 (1):  44-47.  DOI: - Abstract ( 344 )   HTML   PDF (1593KB) ( 758 )   It was found that on access which causes the conflict between parallel applications and shared cache will lead the system performance to degrade for the multi-core processor involving a shared cache. To solve the problem efficiently and reasonably, allocation algorithm is proposed for the shared cache, i.e., sorting and tracking the cases the parallel applications are missing the access as a target to shared cache, then the shared cache is allocated dynamically for cache's line granularity according to the performance gain model developed to improve the system performance. Testing results showed that the new algorithm is able to reduce the conflicting accesses and enable the system to achieve better performance and higher processing efficiency by allocating the shared cache to the parallel operations on multi-core processor reasonably. References | Related Articles | Metrics

Select

Effect of ultra fast cooling on microstructure and mechanical properties of medium carbon steels Wang, Bin (1); Zhou, Xiao-Guang (1); Liu, Zhen-Yu (1); Wang, Guo-Dong (1) 2011, 32 (1):  48-51.  DOI: - Abstract ( 379 )   HTML   PDF (1887KB) ( 780 )   The microstructure and mechanical properties of a certain grade of medium carbon steel were investigated systematically in different controlled cooling processes using the ultra fast cooler provided at the finish rolling exit. It was found that such an ultra fast cooling process can restrain the formation of pro-eutectoid ferrite, and destroy its initial network distribution and minimize the laminar spacing of pearlite obviously. The strength of specimens and their impact toughness at room temperature both increase with the decreasing ultra fast cooling temperature. So, implementing the ultra fast cooling process as just ending the high temperature finish rolling can improve greatly the mechanical properties of specimens and avoid the overloading due to low temperature hot rolling so as to improve the rhythm of rolling production. References | Related Articles | Metrics

Select

Study on quenching process of 960 MPa quenched and tempered steel plates for construction machinery Kang, Jian (1); Lu, Feng (2); Wang, Zhao-Dong (1); Wang, Guo-Dong (1) 2011, 32 (1):  52-55.  DOI: - Abstract ( 290 )   HTML   PDF (1726KB) ( 669 )   To develop the Q960 high-strength quenched and tempered steel plates, the effects of quenching treating regime on the microstructure and mechanical properties of plate specimens were investigated. The results showed that the dissolution and distribution of alloying elements and the original austenite grain size are determined by quenching temperature and holding time and, finally, the overall mechanical properties are obviously affected by the quenching process parameters, and the excellent overall properties of specimens can be obtained when the quenching temperature is 900°C with holding time 15~25 min, i.e., the yield strength is 1110 MPa, tensile strength 1140 MPa and percentage elongation 14% with the Charpy impact energy 130 J at -40°C. All these indexes come up to the national standard GB/T16270-2009. References | Related Articles | Metrics

Select

Strategy of temperature setting for hot-rolled strip cooling after rolling Liu, Wei-Wei (1); Li, Hai-Jun (1); Wang, Zhao-Dong (1); Wang, Guo-Dong (1) 2011, 32 (1):  56-59.  DOI: - Abstract ( 347 )   HTML   PDF (1786KB) ( 573 )   To control the coiling temperature of the hot-rolled strip more accurately, the nonlinearity and strong coupling features of the cooling process were taken into account so as to develop a mathematical model for the temperature control in the cooling process after strip's hot rolling with the nonlinear characteristics involved. Then, the strategy of coiling temperature setting was investigated in relation to the cooling process. A system software was therefore developed on the basis of the model and the effect of the model was verified via in-situ applications. It was found that the setting value of coiling temperature calculated from the model conforms well to the measured value, i.e., the control accuracy of coiling temperature comes up to ±10°C. It means that the model is applicable to actual applications. References | Related Articles | Metrics

Select

Study on ultimate cooling rate during ACC of heavy plates Huo, Wen-Feng (1); Liu, Xiang-Hua (1); Hu, Xian-Lei (1) 2011, 32 (1):  60-63.  DOI: - Abstract ( 414 )   HTML   PDF (1499KB) ( 703 )   The change in temperature during plate cooling was investigated by numerical simulation to analyze how the cooling rate changes with heat transfer coefficient. The results showed that the change of cooling rate with increasing heat transfer coefficient presents an S-like curve, and then the cooling rate becomes stable gradually. With the increasing of heat transfer, when the temperature of plate surface approximates to that of cooling water at finish cooling and the ultimate cooling rate comes true. The ultimate cooling rate is far higher than the cooling rates of both accelerated cooling(ACC) and ultra fast cooling(UFC), and it decreases with the increase in plate thickness and start cooling temperature and decrease in finish cooling temperature. However the cooling water temperature has less influence on the ultimate cooling rate. References | Related Articles | Metrics

Select

Self-adjusting for plate thickness layer skipping in rolling force learning process Ding, Jing-Guo (1); Qu, Li-Li (2); Hu, Xian-Lei (1); Liu, Xiang-Hua (1) 2011, 32 (1):  64-66+71.  DOI: - Abstract ( 355 )   HTML   PDF (1059KB) ( 599 )   In the prediction process of rolling force for plates, to prevent the self-learning coefficient from the skipping along thickness layers, a self-adjusting method was put forward in the self-learning process of the rolling force for medium/thick plates. In the method the half-width zone was calculated according to every thickness node as listed in the table of thickness layers, then the range of validity of a thickness node was calculated according to half-width zone so as to find out the validating range of the thickness during rolling and determine the weighted value corresponding to the relevant thickness node, thus giving the self-learning coefficient after self-adjusting. Practical applications showed that the method proposed is available to improve the prediction accuracy of rolling force and plate shape control greatly and worthy to apply to plate rolling. References | Related Articles | Metrics

Select

Investigation on solidification behavior of Cu-25%Ag alloy in high-intensity magnetic field Li, Gui-Mao (1); Wang, En-Gang (1); Zhang, Lin (1); He, Ji-Cheng (1) 2011, 32 (1):  67-71.  DOI: - Abstract ( 424 )   HTML   PDF (1666KB) ( 514 )   The effect of high-intensity magnetic field on the solidified microstructure of the Cu-25wt%Ag was investigated, as well as the mechanism of the solidification processes of the alloy under different magnetic conditions. It is found that both the uniform magnetic field and gradient magnetic field can affect greatly the solidified structure of the alloy, such as the changes of the size and morphology of Cu-rich dendrites. The primary Cu-rich dendrites are distributed unevenly without magnetic field and they are comparatively thick and long, and most of them are in columnar shape. When the Cu-rich dendrites are in a 12 T magnetic field, they are distributed uniformly and the primary dendrites become short and thick, and most of the dendrites are in cellular shape. When the Cu-rich dendrites are in a negative gradient magnetic field, they are distributed unevenly, and the quantity of dendrites decrease at the bottom of samples where most of the dendrites are in faceted growth and thick cellular shape. Experimental results showed that the constantly uniform magnetic field is feasibly to control the solidified structure of the Cu-Ag alloy and available to grain refining and reducing segregation. References | Related Articles | Metrics

Select

On the characteristics of pulsed electromagnetic force: Theoretical analysis Hua, Jun-Shan (1); Zhang, Yong-Jie (1); Wang, En-Gang (1); He, Ji-Cheng (1) 2011, 32 (1):  72-75.  DOI: - Abstract ( 469 )   HTML   PDF (1558KB) ( 712 )   The characteristics of PMF(pulsed magnetic field) force for grain refinement in solidification process was analyzed through mathematical analytic method. The main peculiarities of PMF force were shown as follows: It was found that the direction of PMF forces changes instantaneously in an individual impulse discharging period, and the PMF forces inside and outside the melt are in different directions in a certain period. In addition, the PMF force is attenuating in an individual impulse discharging period. All the three characteristics are the main reasons why the melt oscillates under PMF. Besides the characteristics as above, the PMF force has a stirring effect on melt in the medium-frequency PMF as used in this investigation. Futhermore, when the pulsed discharge frequency is equal to the natural frequency of solidification system, a resonance will happen to enhance the effect of pulsed magnetic force on solidification processing. References | Related Articles | Metrics

Select

Room temperature mechanical properties and microstructure evolution of LZ63 and LZ113 alloy sheets Cao, Fu-Rong (1); Guan, Ren-Guo (1); Ding, Hua (1); Li, Ying-Long (1) 2011, 32 (1):  76-80.  DOI: - Abstract ( 332 )   HTML   PDF (677KB) ( 544 )   New-type sheets of Mg-6Li-3Zn and Mg-11Li-3Zn alloys were prepared by melting/casting, homogenization and hot/cold rolling. Their mechanical behavior at room temperature, microstructures after hot rolling and lithium loss phenomenon during hot rolling were all investigated. The tensile strength and true strain of fracture at room temperature of the two alloy sheets were measured as 208 MPa/0.13 and 170 MPa/0.375, respectively. The room-temperature relationship between true stress and true strain revealed that the work-hardening occurs in Mg-6Li-3Zn sheet while the work-softening occurs in Mg-11Li-3Zn sheet. The reasons why the work-softening occurs are that the β phase at room temperature is still in the range of recovery temperature, its stacking fault energy is low and the rapid diffusion of Li atoms in β phase reduces the generating rate of dislocation. The sheet microstructures after hot rolling consist of banded grains. It was found that the heavy lithium loss and lots of α phases appear during the hot rolling at 573?K of Mg-11Li-3Zn alloy sheet. The Li loss is caused by the extremely fast diffusion velocity of Li atoms and results in α phase increasing and β phase decreasing in volume fraction. References | Related Articles | Metrics

Select

Structure and performance of zirconia ceramic film on aluminum sheet Wang, Shuang-Hong (), Wang, Lei (), Liu, Chang-Sheng (), An, Cheng-Qiang () 2011, 32 (1):  81-84.  DOI: - Abstract ( 388 )   HTML   PDF (1538KB) ( 991 )   The zirconia ceramic film was deposited on aluminum sheets via fluorozirconate treatment. The morphology and composition of the ceramic film were investigated by scanning electron microscopy and energy dispersive spectrometer, and its corrosion resistance was tested electrochemically. Moreover, the adhesion and salt spray resistance of the ceramic films and substrate were investigated via adhesion test and neutral salt spray test, respectively. The results showed that the ceramic film is nanofilm and colorless and consists mainly of the Zr, Si and Al oxides. The resistance to electrochemical corrosion of the film is high, and its adhesion to the epoxy resin paints or polyurethane paints is of the Grade I. Both the film and substrate have passed 600 h salt spray test. So, the zirconia ceramic film can be used as the backing film on aluminum sheets surface for subsequent painting, and it is expected to be the pretreatment process instead of the heavily-pollutive phosphorization technology. References | Related Articles | Metrics

Select

Influence of citric acid on synthesis of powdered hydroxyapatite with Ca(NO3)2-P2O5 system Chang, Qing (1); Ru, Hong-Qiang (1); Yu, Liang (1); Zhang, Xian-Tie (1) 2011, 32 (1):  85-88+93.  DOI: - Abstract ( 357 )   HTML   PDF (1209KB) ( 683 )   The powdered nano-hydroxyapatite (HA) powders was synthesized by sol-gel method with Ca(NO3)2 · 4H2O and P2O5 as main starting materials and citric acid (CA) as chelating agent. With the influencing mechanism discussed, the influence of CA on the formation process of HA nanopowder and its phase purity and particle size was investigated via DSC, XRD, and SEM. The results showed that CA adding improves the gel's stability and the HA formation process is changed by chelation. The contents of CaO phase in HA nanopowder obtained after CA adding are reduced obviously in comparison with the powder prepared without CA added in precursors. Moreover, CA adding can suppress the agglomeration of powder particles thus making the powder particles of synthesized nano-HA finer and more even with high dispersibility. References | Related Articles | Metrics

Select

Effect of chemical compositions on microstructure and properties of wear-resistant casting steels Zhang, Guo-Zhi (1); Tian, Xue-Feng (1); Liu, Xing-Gang (1); Sun, Guang-Ting (1) 2011, 32 (1):  89-93.  DOI: - Abstract ( 369 )   HTML   PDF (1365KB) ( 772 )   A novel dual-phase (martensite plus bainite) wear-resistant casting steel for caterpillar band was designed and tested to overcome the shortcomings of high-Mn steel, such as the low mechanical properties especially the wear-resistant properties. The results showed that the microstructure of the specimens consist of martensite and bainite with the least amount of residual austenite after quenching tempering. With the increasing carbon content in specimen, its elongation and impact toughness tend to decrease, while the impact toughness remained increasing after quenching and tempering with increasing Cr content. Comparatively, the best mechanical properties belong to those specimens in which the carbon and chromium contents are 0.30% and 0.60%, respectively, with the bainite dual-phase structure. After the grinding test for 400 h, the casting steel specimens show the wearability which is 56% higher than high-Mn steel under dry friction conditions and 22.5% higher than high-Mn steel under wet friction conditions involving corrosive medium. References | Related Articles | Metrics

Select

Development and application of melting rate control in electroslag remelting process Deng, Xin (1); Jiang, Zhou-Hua (1); Dong, Yan-Wu (1) 2011, 32 (1):  94-97+105.  DOI: - Abstract ( 251 )   HTML   PDF (1463KB) ( 793 )   The melting rate control of ESR furnace as a process technology was developed via introducing the coaxial high-current cables, weighing system and intelligent control, and it has been applied in production. The problems of poor-quality crystals inside remelted ingot and that the feeding process cannot be performed exactly because the melting rate is impossibly controlled exactly in conventional ESR furnace are therefore solved. The results showed that the melting rate of electroslag can be readjusted continuously in the range from 5 kg/min to 20 kg/min in actual production, and the power consumption &le1340 (kW · h)/t in remelting a 20 t ingot. Comparing the quality check data of MC5 remelted ingots prepared with either melting rate control or decreasing power, it was shown that the segregation of ingot is reduced with decreased carbide precipitates in the ingot, thus producing high-quality surface and implementing the fully automatic process of production. In this way we get rid of the imported equipment on which the domestic melting rate control system for ESR furnace relies and give impetus to the development of melting rate control for ESR. References | Related Articles | Metrics

Select

Optimal distribution of by-product gases in iron and steel complex Zhang, Qi (1); Cai, Jiu-Ju (1); Pang, Xing-Lu (1); Jiang, Wen-Hao (2) 2011, 32 (1):  98-101.  DOI: - Abstract ( 338 )   HTML   PDF (1286KB) ( 730 )   The optimal distribution of the gas as the by-product of an iron and steel complex between the gas holder and the boiler in its self-supply power plant is discussed, involving the effects of the position control of gas holders, change in fuel loading of the boiler and variation of purchase price of additional fuel on the cost of operation. An optimal gas distribution model is thus developed with a relevant penalty function deduced to solve these problems. The results indicated that the optimal gas distribution between gas holders and self-supply power plant is available to decrease the fuel purchased externally and reduce the frequent change in fuel loading of the boiler, thus improving the power supply efficiency and enabling the zero gas emission so as to make the operation of gas supply system safe, economic and stable. References | Related Articles | Metrics

Select

In-situ synthesis of (O'+β)-Sialon/mullite composite materials Ma, Bei-Yue (1); Li, Ying (1); Xu, Li-Bing (1); Zhai, Yu-Chun (1) 2011, 32 (1):  102-105.  DOI: - Abstract ( 376 )   HTML   PDF (946KB) ( 580 )   (O'+β)-Sialon/mullite composite materials were synthesized by in-situ carbothermal reduction-nitridation process, with fly ash and carbon black as raw materials. The influences of carbon content on phase composition and microstructure of the synthesized materials were investigated by XRD and SEM, and the formation process of the materials was analyzed. The results indicated that increasing carbon content benefits the formation of O'-Sialon and β-Sialon. The (O'+β)-Sialon/mullite composite materials can be synthesized at 1350°C for 6 h, where the mass ratio of fly ash to carbon black in samples are 100/42 and 100/56 separately. The O'-Sialon and β-Sialon in the synthesized materials are in particle shape with an average grain size about 1 μm. The formation process of (O'+β)-Sialon/mullite composite materials consists of the formation of O'-Sialon and β-Sialon in addition to the conversion process of O'-Sialon to β-Sialon. References | Related Articles | Metrics

Select

Preparation and luminance of RE-doped luminescent powder CaMoO4: Eu3+ Chen, Xue-Bing (1); Shao, Zhong-Bao (2); Tian, Yan-Wen (1); Liu, Liao-Wang (1) 2011, 32 (1):  106-109.  DOI: - Abstract ( 266 )   HTML   PDF (1356KB) ( 674 )   The RE-doped luminescent powder CaMoO4: Eu3+ was prepared by chemical precipitation method with the ammonium molybdate, carium nitrate and europium oxide as raw materials. Experimental results showed that the high-quality single-phase luminescent powder CaMoO4: Eu3+ was prepared with the process parameters that the pH value of solution is about 7, reaction temperature is 60°C, sintering temperature is 900°C and the dosage of the dopant Eu3+ is 25wt%. The CaMoO4: Eu3+ products were characterized by XRD and excitation-emission spectrography. It was found that the powder can be excited efficiently by the ultraviolet light with wavelength 394 nm or visible blue light with wavelength 465 nm, and the highest luminous intensity is at 616 nm on the emission spectrum, where the luminescence is in reddish tone due to the dominant electric dipole transition from 5D0 to 7F2. The luminescent powder CaMoO4: Eu3+ is therefore a prospective reddish-tone phosphor applied to achromatic-light LEDs. References | Related Articles | Metrics

Select

Synthesis and properties of chiral liquid crystal polymers containing electron-withdrawing group He, Xiao-Zhi (1); Mu, Qiang (1); Zhao, Jing (1); Zhang, Bao-Yan (1) 2011, 32 (1):  110-113.  DOI: - Abstract ( 270 )   HTML   PDF (1571KB) ( 633 )   The liquid crystalline monomers: M1 (4-allyloxy-phentylpropionyloxycholesterol ester) and M2 (4-undecanoyloxy-4-cyanogen-biphenyl ester) were synthesized. Then, a series of chiral liquid crystalline polymers containing electron withdrawing groups were prepared via graft copolymerization with the dosages of M1, M2 and PMHS(polymethylhydrosiloxane) as backbone in a certain proportion. The chemical structures of both the monomers and polymers thus obtained were confirmed by FT-IR and 1H NMR spectra, and the mesomorphic properties were investigated by DSC, POM, TG and X-ray. Experiment results showed that M1 and M2 are cholesteric and nematic liquid crystal monomers, respectively, and polymer P1 smectic but P2~P8 are chiral smectic A polymers. Furthermore, the glass transition and clearing points of the polymers tend to increase with the increasing content of M1, with a wide range of liquid crystalline phase provided. References | Related Articles | Metrics

Select

Sound absorbility of closed-cell aluminum foam Liang, Li-Si (1); Yao, Guang-Chun (1); Mu, Yong-Liang (1); Hua, Zhong-Sheng (1) 2011, 32 (1):  114-116+132.  DOI: - Abstract ( 317 )   HTML   PDF (1555KB) ( 666 )   The sound absorbility of closed-cell aluminum foam was further investigated in view of some factors, including density, thickness, back cavity depth and perforation rate. Instead of the only characteristic factor, i.e., the peak value of sound absorption coefficient, the sound absorbility of closed-cell aluminum foam was therefore evaluated through three indices, i.e., the peak value above mentioned, denoising coefficient and half peak width. With the sound absorption coefficient measured by standing-wave meter and the sound absorption curves analyzed by the software Origin, the corresponding functional relation was established. The results showed that in previous tests some specimens showed unfavorable effect of sound absorption as a whole though their peak values of sound absorption coefficient were high, while the other samples showed high sound absorption effect as a whole though their peak values were medium. So, the new method proposed to evaluate the sound absorbility is more actual and suitable for the design of sound absorption system. References | Related Articles | Metrics

Select

Acoustic robustness design of intake system of vehicle engine Yue, Gui-Ping (1); Zhang, Yi-Min (1) 2011, 32 (1):  117-120.  DOI: - Abstract ( 262 )   HTML   PDF (1001KB) ( 472 )   Sometimes the acoustic reliability in the intake system of vehicle engine decreases with increasing acoustic robustness, and to solve the problem the reliability-based design of acoustic robustness was studied. Combining the theories of pipe acoustics, reliability design and robustness design together, taking the acoustic reliability analysis as a precondition, the acoustic robustness in the intake system of a vehicle engine was optimized. The acoustic robustness design based on acoustic reliability is therefore available to get the information on the optimized parameters in acoustics design of the intake system, thus meeting acoustic design requirements for both reliability and robustness, and providing a quantified reference for the design. References | Related Articles | Metrics

Select

On the image fusion rules of strip surface defects based on dissimilarity between local variances Yan, Yun-Hui (1); Song, Ke-Chen (1); Peng, Yi-Shu (1); Li, Jun (1) 2011, 32 (1):  121-124.  DOI: - Abstract ( 479 )   HTML   PDF (1042KB) ( 1048 )   Nowadays the fusion rules of the images of strip surface defects are one-sided, since they are based on the single point coefficient and the features of regional coefficient, thus making the images easy to be distorted. To solve the problem, the new fusion rules are presented where the high-frequency sub-bands are fused together after wavelet decomposition, with the dissimilarity between the local variances of the two images to be fused taken fully into account, then the thresholds are set to select the appropriate fusion rules. Experimental results showed that the method proposed can keep up the image features in detail and is highly applicable to the image fusion of surface defects of cold-rolled strip. References | Related Articles | Metrics

Select

Cross-sectional geometry of drifts in gently sloping layered rock and support method Ren, Feng-Yu (1); Ding, Hang-Xing (1); Zhang, Dong-Hong (2); Zhang, Jin-Jun (2) 2011, 32 (1):  125-128.  DOI: - Abstract ( 290 )   HTML   PDF (1554KB) ( 731 )   The poor rock stability and high ground pressure in the western zone of the Chambishi Copper Mine in Zambia resulted in serious roof failure of the along strike drifts. The reasons of roof failure and the following changes in the surface stress of drifts were analyzed under the conditions of gently sloping layered surrounding rock. Furthermore, a conclusion was drawn that the drift section after roof failure tends to be stable, because it becomes self-adaptive to rock mass structure and pressure since then. Therefore, an erect triangular cross-section of the drift is proposed instead of the existing 1/4 tri-center arch section, with rock bolts used to stabilize the rock structure. After the implementation of the scheme, the stability conditions of drifts were significantly improved and the utilization ratio of drifts was increased from 90% to 100%, i.e., a remarkable success. References | Related Articles | Metrics

Select

Experimental study on the effect of high-density surface structure on filtration performance of needle-punched felt Liu, Jing-Xian (1); Mao, Ning (1); Chang, De-Qiang (1); Sun, Xi (1) 2011, 32 (1):  129-132.  DOI: - Abstract ( 266 )   HTML   PDF (1745KB) ( 602 )   With an experimental setup used according to the National Standard, the filtration performance of both the common and high-density surface needle-punched felt as filters was systematically investigated, and the data of filtration resistance were obtained. The results showed that the high-density surface needle-punched felt as a filter shows the typical characteristics of surface filtration at different filtering stages, i.e., the fresh, aged, and stabilized filters are used sequentially. The high-density surface needle-punched felt is superior to the common one in filtration performance as follows: low filtration resistance and its slow increasing rate, long-time filtration cycle and high dust stripping rate. References | Related Articles | Metrics

Select

Ecological footprint & intensity of solid waste disposal in Shenyang Feng, Min (1); Gu, Xiao-Wei (1); Wang, Qing (1); Wang, Feng-Bo (1) 2011, 32 (1):  133-135+144.  DOI: - Abstract ( 302 )   HTML   PDF (761KB) ( 427 )   Based on the componential method of ecological footprint (EF) computation, a model was developed to calculate the EF of urban solid waste so as to quantify its environmental pressure. With the model applied, the EF of urban solid waste in Shenyang was calculated from 1990 to 2005. The results indicated that almost the entire EF results from the equivalent forest area required for absorbing the greenhouse gas from waste's degradation, i.e., about 200000 hm2 in 1990 and 150000 hm2 in 2005. In addition, the quantity of solid waste and its disposal intensity were analyzed. The results showed that the quantity was 1.24 t in 1990 and 0.36 t per RMB 10000 of GDP in 2005 with an annual reduction rate of 7.87%, and the disposed quantity of waste was 0.89 t in 1990 and 0.17 t in 2005 with an annual reduction rate of 10.61%, where the GDP was calculated at the fixed price of the secondary and tertiary industries in the city in 2000. Thus, with respect to the quantity and disposal of solid waste, the environmental efficiency in Shenyang's economic development was rising at a relatively high speed. References | Related Articles | Metrics

Select

Method for interval multiple attribute decision-making considering decision-maker's psychological behavior Fan, Zhi-Ping (1); Chen, Fa-Dong (1); Zhang, Xiao (1) 2011, 32 (1):  136-139.  DOI: - Abstract ( 318 )   HTML   PDF (1601KB) ( 607 )   A method was proposed to solve the interval multiple attribute decision-making problems with the decision-maker's psychological behavior considered. In view of the reference dependence traits of decision-maker's psychological behavior, the gain or loss relative to the reference points corresponding to the consequence of each attribute in every alternative was calculated according to prospect theory, with a matrix of gain or loss built. Then, aiming at the loss aversion trait of the decision-maker's psychological behavior, the decision maker's comprehensively perceived value of the gain or loss of every alternative was calculated according to the basic idea of TODIM method. Furthermore, all the alternatives were ranked according to the known comprehensively perceived values. A numerical example is given to illustrate the feasibility and validity of the proposed method. References | Related Articles | Metrics

Select

On the interpersonal trust and tacit knowledge transfer between corporations after M & A - Exemplification with Baosteel Group Du, Xiao-Jun (1); Wang, Xiao-Gan (1); Min, Lin-Lin (1); Han, Lu (1) 2011, 32 (1):  140-144.  DOI: - Abstract ( 297 )   HTML   PDF (1076KB) ( 561 )   A conceptual model was developed for the effect of interpersonal trust on the tacit knowledge transfer between corporations, since such a transfer relies on the mutual trust in a certain field of knowledge via the ″neighboring interaction″ through interpersonal exchange. Applying the structural equation to the model to verify it with the M&A implemented by Baosteel Group corporations as example, the results showed empirically that in the process of tacit knowledge transfer after M&A, the emotional trust has positive correlation with the willingness, worthiness and exploratory mode of tacit knowledge transfer, while the cognitive trust has negative correlation with the worthiness and exploratory mode of tacit knowledge transfer. Moreover, there is a positive correlation between institutional trust and willingness of tacit knowledge transfer. References | Related Articles | Metrics

Select

On the risk-based collaborative quality control for supply chain of perishable goods Zhang, Cui-Hua (1); Lu, Li-Li (1) 2011, 32 (1):  145-148.  DOI: - Abstract ( 248 )   HTML   PDF (746KB) ( 795 )   The risk-based solution to the problem of collaborative quality control for supply chain of perishable goods was investigated considering three cases, i.e., the purchaser hid the information on quality evaluation, the supplier hid the information on quality prevention and both information was hidden. The principal-agent models of collaborative quality control for supply chain of perishable goods were developed according to the quality risk share level between the supplier and purchaser. Then, the penalty level for quality defect and the share to be taken by both parties for exterior loss were given via decision optimization so as to achieve the optimal objective, i.e., the whole supply chain gain is biggest with the maximum profits available to either supplier or purchaser. A numerical example is given to illustrate the collaborative quality control model under different conditions. References | Related Articles | Metrics

Select

Empirical research on the impact of managers participating in budgeting on management performance Wu, Li (1); Wang, Fang-Fang (1); Yuan, Zhi-Zhu (1) 2011, 32 (1):  149-152.  DOI: - Abstract ( 211 )   HTML   PDF (1006KB) ( 572 )   The attitude to budgeting and relevant incentives as the variables were introduced in budgeting process with the questionnaires returned to analyze further the relationship between managers' behavior of participating in budgeting and management performance, thus developing a structural equation model. It was found that there was a positive correlation between the managers who have participated in budgeting and management performance, and the relevant incentives can regulate such a correlation, i.e., the incentives directly regulate the relation between managers' participation and management performance, while managers'attitude to budgeting as a mediating variable indirectly regulate the relation. References | Related Articles | Metrics