1997 Vol. 4, No. 4

Display Method:
Application of Artificial Neural Networks to the Classification of Coal Reserve Assets
WANG Guangcheng, LI Xiangyi, and  LI Thongxue
1997, vol. 4, no. 4, pp. 1-4.
Abstract:
Using the classification results by the fuzzy clustering models as the basis for choosing the choosing patterns, a feed forward networks model for classification is given. Remarkable success was achieved in training the networks to learn the patterns and in classifying the coal reserve assets. The results show that the neural network approach for classification has some advantages such as stability and reliability.
Preventing Occurrence of Transverse Corner Cracks on Nb, V and Ti Microalloying Steel CC Slabs
WANG Xinhua, WANG Wenjun, WU Dongmei, CHANG Bo, LIU Xinyu, ZHANG Li, and  YE Jinwei
1997, vol. 4, no. 4, pp. 5-9.
Abstract:
Based on their hot ductilities, Nb, V and Ti microalloying steels can be classified into two groups. The first group includes steels with lower carbon content (≤0.10%). Ductilities of steels of this group recover and rise with decreasing temperature when temperature lowers to below 825℃. Another group includes steels which contain more carbon (>0.12%) or contain more Nb and V. The low ductility temperature Region Ⅲ for steels of mis group extends to temperature as low as 725℃. The occurrence of the transverse corner cracks of the Nb, V and Ti microalloying steel CC slabs has be considerably decreased by stabilizing casting speed, increasing mold steel level automatic control ratio,enhancing caster segment radial alignment and adopting proper secondary cooling patterns to make slab corner temperature at straightening out off the low ductility temperature region.
Establishment and Application of A Mathematical Model for Rectangular Billet Continuos Casting
IJU Qing, TIAN Nianyuan, WANG Yingqun, WU Xiaodong, HOU Wenyi, XU Mingxin, XIANYU Jintang, and  ZHANG Xiumu
1997, vol. 4, no. 4, pp. 10-14.
Abstract:
A two dimension unsteady heat transfer model is established for rectangular billet casting. Solidification process of liquid steel in secondary cooling zone was analyzed using direct difference method. The influence of operation parameters including casting speed and temperature of liquid steel was investigated. Experimental results have been used for increasing the casting speed.
Roles of Metallic Oxides in the Elimination Reactions of NO
XU Chunbao, WU Shengli, SHOU Qiushuang, and  CANG Daqiang
1997, vol. 4, no. 4, pp. 15-18.
Abstract:
The catalytic effect of several metallic oxides(Fe2O3, Cr3O3 and Ni2O3) on elimination of NO has been studied in a flow type reactor, and the roles of metallic oxide in the elimination reactions of NO has also been discussed. The results show that in the system of NO-CO-CO2-N2, the catalytic reaction of NO/CO on the metallic oxide plays a leading role in NO elimination especially for Fe2O3 and Cr2O3 samples. However, Ni2O3 and its pre-reduced samples show extremely remarkable catalytic effect on direct decomposition of NO.
Mathematical Model of Decarburization of Ultra Low Carbon Steel during RH Treatment
ZHANG Lifeng, JING Xuejing, LI Jiying, XU Thongbo, and  CAI Kaike
1997, vol. 4, no. 4, pp. 19-23.
Abstract:
According to the balance of carbon and oxygen, a decarburization model for the RH treatment has been developed. in which the influence of the mass transfer of carbon and oxygen in the liquid steel and the stirring energy (ε) in the vacuum vessel on decarburization rate has been considered. The conclusion that the volumetric coefficients of the mass transfer of carbon is proportional to ε1.5 is drawn. Industrical experiment proves this model is reliable. The influence of some factors on decarburization rate has been obtained. which can provide directions for RH treatment The decarburization behavior of steel with RH-OB treatment is also studied. The OB-or-not curve, the optimized OB time and OB amount are discussed.
Preliminary Ferrographic Study of the Wear Particles in Synovial Fluid of Human Knee Joints
GU Thenqiu, LOU Siquan, SHI Xuesu, ZHANG Xianghong, XIAO Jiumei, and  YANG Lin
1997, vol. 4, no. 4, pp. 24-27.
Abstract:
The technique of ferrography has been applied to study the wear particles in synovial fluid of human knee joints. As a result some discrete, identifiable kinds of wear particles were found and various wear mechanisms, for example, adhesive wear, fatigue wear,etc. were revealed. Ferrographic techique may provide a method for early differential diagnosis, and prognostication concerning the future course of the disease.
Development of Rare Earth Hydrogen Storage Alloys: Correlation Between Structure, Stability, and Hydrating Properties
ZHAO Chuang, LIN Qin, CHEN Ning, YE Wen, and  MA Li
1997, vol. 4, no. 4, pp. 28-33.
Abstract:
The structure of β-LaNi5Hx is mentioned. Special emphasis is laid on the influence of substitutions with metallic elements on the thermodynamic properties of the rare-earth-nickel hydrogen storage alloys. The models of the heat of hydride formation are studied attentively. The relation between the stability and the heat of formation of intermetallic compounds including with other physical properties is discussed. The relations between hydriding properties and the geometric and electronic structure of the intermetallic compounds are presented.
Sintering Behavior and Microstructure of diphasic β-Sialon/Al2O3 Composites
LI Youfen, HONG Yanruo, ZHONG Xiangchong, and  LI Tingshou
1997, vol. 4, no. 4, pp. 34-38.
Abstract:
Six compositions with different ratio of β-Sialon/Al2O3 were synthesized from Al2O3, Si3N4 and SiO2 by sintering with 3%Y2O3(mass fraction) as addition under the cover with powders of SiC+C and at nitrogen atmosphere. Theeffects of atmosphere, sintering temperature and composition on the sintering behavior were studied. The results showedthat the composites reached the best sintering behavior with the highest density about 92% at 1 650℃ under the weakreduction atmosphere. Finally the relative density of diphasic β-Sialon and β-Sialon/Al2O3 composites were studied andpredicted using ANN (Artificial Neural Networks) method and the results were experimental examined by fore randomsamples.
Factors Influencing the Sulfidation Rate of Fe-Mo Binary Alloys
LIU Haiping, QI Huibin, HAO Chanshan, WANG Xiaohong, HE Yedong, and  ZHU Rizhang
1997, vol. 4, no. 4, pp. 39-42.
Abstract:
The sulfidation rate constants of various Fe-Mo binary alloys in S2 vapor with different sulfidation parameters were collected to summarize the correlation between the sulfidation rate and alloy composition, sulfur pressure and sulfldation temperature. The octivation energies indicate that the sulfidation process of the alloys is exclusively controlled, at a given temperature, by one alloying component i.e. either Mo or Fe. The sulfidation rate declines exponentially with the increasing of Mo content in alloy. And the influence of sulfur pressure is relatively slight.
Preparation of Nanometric Particles of Aluminum Nitride by Pyrolysis of Diethylaluminun Azide
YE Yaping, ZHOU Keyan, GAO Thznxian, SUN Yu, and  LU Bingling
1997, vol. 4, no. 4, pp. 43-46.
Abstract:
Thermal stabilities of diethylaluminum azide were studied by means of theoretical analysis and expriments.The results have shown that diethylaluminum and azid be heated to vigorous refluxing under vacuum(400 Pa) at temperature as high as 420℃ without incident of explosion and decomposes smoothly during 460~580℃ to form nanometric particles of aluminum nitride in the aerosol synthesis reactor. A new way of preparing nanometric parties of aluminum nitrideis found.
High Speed Steel and WC Particle-Reinforced Composites Produce by Spray Forming
ZHANG Wing, HUANG Thuo, TIAN Haige, WU Qinghua, and  WU Chengyi
1997, vol. 4, no. 4, pp. 47-51.
Abstract:
The process of spray forming utilized to fabricate WC particle-reinforced high speed steel composites has been studied. In addition, microstructures and mechanical properties of M2 high speed steel and its composites made by spray forming have been analyzed. The results show that the primary carbides of high speed steel are of two types: MC and MbC. With the increase in flight distance, the morphology of the primary carbides varies from fine fish-bone-like to islandlike and both bending strength and hardness increase. With the increase in volume fraction of WC reinforcement particles,hardness of the composites increases considerably, but bending strength, however, appears to be a decreasing tendency.
Study on Speeding up the Back-Propagation Algorithm
TANG Ying, SUN Rongping, and  CHEN Kexing
1997, vol. 4, no. 4, pp. 52-54.
Abstract:
Slow convergence of back-propagation (BP) algorithm is a limiting factor in its practical applications. A new learning algorithm which can adaptively adjust its learning rate on the basis of gradient information of the error function is put forward. its convergence performance is also tested by the XOR problem compared with the standard BP algorithm.
Nonclassical Plane-crystallographic Groups and Their Applications Ⅲ
MIN Lequan and  ZHANG Xiaodan
1997, vol. 4, no. 4, pp. 55-60.
Abstract:
Six kinds of nonclassical periodic lattices with locally 10-fold rotational symmetries are proposed. They can be delineated via nonclassical plane-crystallographic groups. The projections on the planes of corresponding unit cells consisting of embedding polyhedra generate the periodic lattices, respectively. The Fourier-transform patterns of the periodiclattices have almost perfect 10-fold rotational symmetries, which are very similar to those displaying in the electron-diffraction patterns of so-called quasicrystals.