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121.
Jiayong Cao Yu Zhu Jinsong Wang Wensheng Yin Guanghong Duan 《IEEE transactions on magnetics》2004,40(6):3490-3494
This paper investigates three kinds of permanent-magnet arrays used in planar motors with polarity centers distributed in the lattices of a matrix. The magnetic field of every kind of magnet array is analyzed by analytical methods. First, we give a Laplace equation of magnetic scalar potential and a series of boundary conditions. Then, we derive the analytical expressions of magnet field strength and magnet flux density in the air gap of each kind of magnet array by the method of separation of variables. Finally, we compare the three types of magnet arrays on the basis of the analytical solutions. 相似文献
122.
123.
O. T. Tsyrul’nyk H. M. Nykyforchyn D. Yu. Petryna M. I. Hredil’ I. M. Dz’oba 《Materials Science》2007,43(5):708-717
We study the degradation of the mechanical and corrosion properties of 17G1S steel in gas mains as a result of operation for
28–40 yr. We reveal the simultaneous decrease in its strength and hardness, on the one hand, and impact toughness and crack
resistance, on the other hand. The indicated parameters prove to be most sensitive to the in-service degradation of the metal.
The degradation of steel leads to the increase in the strain-hardening coefficient and the appearance of the yield plateau
in the tensile stress-strain diagram and causes the appearance of sensitivity to hydrogen embrittlement increasing in the
process of operation. We analyze the role of absorbed hydrogen affecting the mechanism of strain aging and responsible for
the appearance of defects. It is shown that the polarization resistance can be used not only for monitoring of the corrosion
state of gas pipelines but also for the prediction of changes in their mechanical properties in the process of operation.
__________
Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 5, pp. 97–104, September–October, 2007. 相似文献
124.
A new diffuser capable of scattering light in one direction (one-dimensional diffuser) has been developed and experimentally
tested. The diffuser is formed in a thick layer of dichromated gelatin. The scattering indicatrices of the diffuser measured
in two mutually perpendicular directions are presented. It is demonstrated that the indicatrix width in one direction is significantly
greater than that in the perpendicular direc-tion. However, no zero-order diffraction has been observed. The proposed one-dimensional
diffuser exhibits close scattering indicatrices for reading at a wavelength of 0.44 and 0.63 μm. 相似文献
125.
Yu. S. Kan 《Automation and Remote Control》2003,64(2):263-278
For the nonantagonistic two-person game which is equivalent to the problem of minimizing the quantile function, a modification of the stochastic quasigradient algorithm to seek the Nash point was proposed. The Nash point defines both the optimal strategy minimizing the quantile function and the minimum value of this function. Convergence of the algorithm with the probability 1 was proved. The question of choosing the starting point was discussed. 相似文献
126.
A. Yu. Luchka 《Cybernetics and Systems Analysis》2003,39(6):880-888
A modified variational-gradient method is proposed and substantiated for quasilinear operator equations in a Hilbert space. 相似文献
127.
E. M. Gavrishchuk E. Yu. Vilkova O. V. Timofeev U. P. Borovskikh E. L. Tikhonova 《Inorganic Materials》2007,43(6):579-583
Chemical interaction between polished surfaces of polycrystalline zinc selenide and inorganic acid solutions of various concentrations has been studied. 相似文献
128.
Itwasreported[1] thatthemicro stereostructureofprimaryausteniteincastironconsistsofprimarystemsandsecondaryarmsthat growaccordingtodendritecrystalsbranchrule ,andsomeofprimaryausteniteevenhavethirdarms .MiyakeHetal[2 ]proposedaconceptofregionmodelbystudying… 相似文献
129.
M. Kangas J. Villegas N. Kumar T. Salmi D.Yu. Murzin F. Sandelin E. Harlin 《Catalysis Today》2005,100(3-4):363-366
An investigation of the effect of reaction conditions on product distribution in the skeletal isomerisation reaction of linear butenes has been carried out. The main reaction routes over ferrierite have been identified. Beside the main product isobutene, major by-product formation occurs. The unwanted reactions include dimerisation of butene to form octenes, hydrogen transfer yielding small amounts of saturated C3 and C4 hydrocarbons and disproportionation producing propene and pentenes. The most abundant by-products were pentene and propene, though these were not formed in equimolar amounts as could be expected. Oligomerisation experiments of propene over ferrierite produced large amounts of butene and pentene, revealing the presence of adsorbed nonene. The cracking of this surface species to hexene and propene is the most likely reaction route for the excess propene formation. This additional path to propene formation operates mainly at temperatures above 623 K. 相似文献
130.
Yi‐Hung Chen Ching‐Yuan Chang Wei‐Ling Su Chun‐Yu Chiu Yue‐Hwa Yu Pen‐Chi Chiang Chiung‐Fen Chang Je‐Lueng Shie Chyow‐San Chiou Sally IM Chiang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(1):68-75
This study investigates the ozonation of CI Reactive Black 5 (RB5) by using the rotating packed bed (RPB) and completely stirred tank reactor (CSTR) as ozone contactors. The RPB, which provides high gravitational force by adjusting the rotational speed, was employed as a novel ozone contactor. The same ozone dosage was separately introduced into either the RPB or the CSTR for the investigation, while the experimental solution was continuously circulated within the apparatus consisting of the RPB and CSTR. The decolorization and mineralization efficiencies of RB5 in the course of ozonation are compared for these two methods. Moreover, the dissolved and off‐gas ozone concentrations were simultaneously monitored for the further analysis. As a result, the ozone mass transfer rate per unit volume of the RPB was significantly higher because of its higher mass transfer coefficient and gas–liquid concentration driving force. Furthermore, ozonation kinetics was found to be independent of the gravitational magnitude of an ozone gas–liquid contactor. Therefore, the results suggest employing RPBs as ozone‐contacting devices with the advantage of volume reduction. The experimental results, which can be used for further modeling of the ozonation process in the RPB, also show the requirement of correct design for the RPB. Consequently, the present study is useful for the understanding of practical application of RPBs. Copyright © 2004 Society of Chemical Industry 相似文献