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 共查询到19条相似文献,搜索用时 250 毫秒
1.
本文着重介绍了Foundation Field bus总线技术的基础和发展,介绍了FF总线技术的核心技术和结构发展历程,并对FF总线技术的优缺点做了分析和比较,同时探讨了FF总线技术的实际意义和对其应用做了展望。  相似文献   

2.
Described in the paper is the method to fit autoregressive(AR)random field models and Gausslan Markov ran-dom field(GMRF)models for textile textures.Maxi-mum likelihood(ML)estimation schemes and texturesynthesis for these models are presented.Three types oftypical textile textures are tested using the method andsatisfactory results are achieved.  相似文献   

3.
Starting from unified field equations we obtain two solutions and an expres-sion for Planck constant: U=32πe~2/v, it has two values as when v=0.731c, U=h; when v=c. U_(min)=0.731h. to gether with the derivationsfor Planck particle, Einstein photon and Dirac spin from such theory etc.  相似文献   

4.
Dendritic Morphology Simulation Using the Phase Field Method   总被引:1,自引:0,他引:1  
Dendritic morphology was simulated using a macro- and micro-coupled method. Since the microstructure of a whole casting cannot be easily analyzed, a scheme was developed to calculate the temperature of the whole casting with the microstructure analyzed by selecting one cell in the central region of the casting. The heterogeneous nucleation was described using a Gaussian distribution with the dendritic growth controlled by the solution of the phase field equation. The initial temperature distribution in the microdomain was obtained by interpolating the cell temperatures near the selected cell with the interface undercooling assumed to be the sum of thermal, solute, and curvature effects. The solute distribution was calculated from the mixed solute conservation equation with noise introduced to produce the side branches. The simulation results agree well with experimental results.  相似文献   

5.
Itisofgreatsignificancetosimulatetheelectrostaticfieldinhighvoltagepowerapparatuseswhichcanimprovetheirstructures.Althoughthereisnospecialprobleminthesimulationofelectrostaticfields,difficultiesstillremaininthedevelopmentofthreedimensional(3D)softw…  相似文献   

6.
Field algebra of G-spin models can provide the simplest examples of lattice field theory exhibiting quantum symmetry. Let D(G) be the double algebra of a finite group G and D(H), a sub-algebra of D(G) determined by subgroup H of G. This paper gives concrete generators and the structure of the observabl ealgebra AH, which is a D(H)-invariant sub-algebra in the field algebra of G-spin models F, and shows that AH is a C^*-algebra. The correspondence between H and AH is strictly monotonic. Finally, a duality between D(H) and A. is given via an irreducible vacuum C^* -representation of F.  相似文献   

7.
IntroductionMetallic card clothing is ani mportant part of the cardmachine . According to the textile industry criterion (FZ/T93038 95) ,the micro-hardness of four testing points onthe garnett wire teeth should be tested in order to decidewhether it is up to standard or not . Fig .1showsschematically these four testing points on a garnett wiretooth of metallic card clothing . The first testing point ofmicro-hardness is at0.05 0.1mm from the tip of thetooth and its value of micro-hardness req…  相似文献   

8.
An effective field renormalization group (EFRG) method, which improves the results of real space renormalization group and mean-field renormalization group (MFRG) methods, is proposed for the study of the bond-diluted Ising ferromagnet.  相似文献   

9.
0 IntroductionThefieldemissiondisplay (FED) ,whichhasthebenefitsofbothliquidcrystaldisplays (LCDs)andcathoderaytube(CRT)display ,isregardedasaperfectchoiceforthefuturedis plays.Ithasacompactsize,alargeviewingangle,excellentbrightnessandhighpicturequality[1 ] .Thefieldemissionarrays(FEAs) ,whichareformedofarraysofmicro tips,arewidelyusedasthesourceofelectroninFED .Thetopofthetipiswherethestrongestelectricfieldis.Itisalsowheremostoftheemissionelectronscomefrom .Thismadeitpossibleto putel…  相似文献   

10.
Galliformes are often difficult to count adequately in their natural habitats due to low detectability of them. In the present study, we confirm availability of feather-count and feces-count as two useful field techniques to estimate the relative abundance of eared-pheasants (Crossoptilon spp. ). The former is suitable to forest environments during the post-incubation period, whereas the latter is best in areas with dry climate conditions during the fall-winter season. With the advantages of reduced survey effort and high repeatability, the two techniques are potentially applicable to other Galliform species in habitat selection studies and long-term population monitoring.  相似文献   

11.
The wear mechanism of metallic card clothing, used in textile industry, was analyzed. A fast wear test for metallic card clothing racks was developed, which was used as collecting the wear metal particles. The failure type of card clothing was analyzed by the mean of scanning electron microscopy (SEM) and ferro-spectrum technology. The results show that the main wear mechanism of metallic card clothing is low load and high repetition interval fatigue wear caused by friction force between fiber and metal wire teeth. The appropriate quenching microstructure, which improves the wear resistance of the metallic card clothing rack is also discussed.  相似文献   

12.
应用三维有限元方法对金属针布的火焰淬火加热进行了研究。将实验测量与人工神经网络建模技术相结合,建立了火焰加热工件表面热流密度的计算模型,解决了三维有限元求解中边界条件的设定问题。用有限元方法求解三维固体热传导的Fourier方程,模拟计算了金属针布火焰快速加热时的温度场变化,计算结果与实测吻合较好。  相似文献   

13.
Main design parameters of MCC (metallic card clothing) which include front angle, base width, tooth pitch, and tooth point dimensions are discussed to investigate the carding effect of MCC. Experimental results show that type C machine has the best carding effect, which is not ascribed to single factor control but the integrated design optimization and good performance of wire teeth. In comparison with the teeth design, the wire performance is another important factor that influences the perfommnce of modem high efficient production carding machine.  相似文献   

14.
本文应用相似性原理,对梳毛机基本分梳作用区进行了简化,建立了金属针布的快速磨损模拟试验,较实际运转情况具有摩擦副不变、分梳作用不变和速比相似的特点。并对十种金属针布进行了耐磨性对比试验,结果表明其相对耐磨性与生产实践相符。这对于金属针布的选用及其耐磨材质的研制是非常有益的。  相似文献   

15.
金属针布快速磨损模拟试验研究   总被引:1,自引:0,他引:1  
针对生产运转条件下研究针布磨损的一系列问题,本文提出了一种金属针布快速磨损模拟试验的新方法,此法与生产运转条件下针布磨损相似:摩擦副相似、摩擦速度相似和摩擦力相似。用此方法对国产新型低合金钢针布SAC35X、SAC42X与国外Graf、ABK和ECC的某些针布作了快速磨损对比试验,并在七至十天内即可预测针布耐磨度。本试验的结果已被大量生产实践所证实。  相似文献   

16.
从针布梳针必须具备的工作特性出发,讨论了梳棉用梳针的形状、倾角、膝上膝下长度及现用梳针的尺寸.还讨论了梳毛机用普通梳针、风轮梳针和开梳针的粗细与截面形以及针布的幅宽和针密.  相似文献   

17.
通过在金属针布梳棉机上专门的抄针实验,研究抄针前后不同时刻的棉结粒数的变化规律。结果表明:金属针布在纯涤纺时仍需要抄针,合理的抄针周期应为每两天一次。  相似文献   

18.
 为了检测PC 桥梁高强钢丝的有效张拉力值,采用自主研发的预应力钢索张力测试仪(LCZL-50),在WED 系列电子万能试验机上进行了试验测试研究。首先通过试验机将高强钢丝张拉到不同预应力值,应用二级横张原理对高强钢丝进行有效张拉力测试,然后基于最小二乘法对试验测试数据进行分析处理,通过回归计算得出高强钢丝的有效张拉力。将该方法用于实桥测试和计算,结果显示,ø5 mm 高强钢丝在较小横张力作用下,横张力与横张位移成线性变化,且满足小变形条件,其有效张拉力实测值与理论值的误差小于5%,表明该方法的测试精度满足实际工程需要,可为PC 桥梁的维护、加固或改造提供技术依据。  相似文献   

19.
通过建立中厚板辊式淬火机淬火过程的热传导控制方程,分析了热交换系数、淬火方式对中厚钢板淬火过程中温度场的影响.分析表明,淬火过程中,一定厚度的钢板,换热系数在一定范围内增大时,对流换热边界条件对钢板表面及内部温度变化影响效果显著;中厚板辊式淬火机淬火过程的特点在于,钢板首先通过冷却强度很大的高压淬火区冷却,使板材内部保持很大的温度梯度,从而保证板材获得较大的冷却速度;在较低冷却强度的低压淬火区完成淬火过程,板材内部温度梯度减小,可降低板材内部热应力.  相似文献   

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