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1.
1 Introduction Microactuators are the key devices of micro-electro-mechanical system( MEMS) . For many MEMS devicessuch as switches , optical attenuators , pumps andvalves to function, microactuators are required . Mo-tion of microactuators can be achieved by several kindsof actuation mechanisms . Electrostatic ,piezoelectric ,magnetostrictive, magnetic ,thermomechanical actua-tors have been reported[1-5].Among the different actu-ation principles ,the electrostatic actuationis predomi-nant…  相似文献   

2.
The outstanding properties of CVD diamond fil msuch as electronic , optical , thermal and mechanicaland the high radiation hardness have made it an idealcandidate material for radiation detectors in severe en-vironments .Fabrication of‘detector grade’CVD dia-mond fil ms and development of CVD diamond detec-tors have been leading edge subjects . Micro-strip gaschamber ( MSGC) fabricated on CVD diamond sub-strate would overcome the charge-up effect and thesubstrate instability, which has…  相似文献   

3.
In this paper,the sensors array technique is applied to the quality detection of aluminum alloy spot welding.The sensors array has three forms,i.e.,linear magnetic sensors array,annular magnetic sensors array and cross magnetic sensors array.An algorithm based on principal component analysis is proposed to extract the signal eigenvalues.The three types of magnetic sensors array are used in the experiment of monitoring the signal.After the eigenvalues are extracted,they are used to build a relationship with ...  相似文献   

4.
1IntroductionThe solidification structure of Bi-Mn alloys solidifiedin a high magnetic field is al ways an interesting topicbecause the alloy is special in solidification behavior.Mikelson,et al[1]and Asai,et al[2,3]found that MnBiphase regularly aligned along the magnetic field inBi-(0.9-10wt%)Mn alloy solidified in the2.5-5Tmagnetic field.Ren,et al[4]found that the aligned so-lidification structure of MnBi phase was basically pro-duced in the semisolid zone of the alloy.Yasuda[5]contribu…  相似文献   

5.
1 Introduction [1-3]The permanent magnetic actuator (PMA) technology first showed up in 1990s. It adopts a new working theory and a novel structure. With the combination of electrical magnetism and permanent magnetism, it can realize all functions of a br…  相似文献   

6.
1IntroductionPlanar waveguides have recently received much at-tention dueto their promising applications inintegratedoptics[1-5].Formation of a waveguide requires a guid-inglayer with the refractive index higher than that ofthe substrate and cladding. The number of guidingmodes depends on thickness and refractive index ofthe guiding layer . Low optical loss is an i mportantproperty of waveguide . Although pure inorganic fil msusing the sol-gel technique have both good mechanicaland thermal st…  相似文献   

7.
1 Introduction Electrical i mpedance tomography (EIT) is a non-in-vasive i maging technique with widespread applicationsin medicine and industry[1 ,2].In EITthe electric cur-rent is injected between all possible pairs of adjacentelectrodes , and voltage is measured among all otherelectrodes and a voltage reference electrode .Based onthese boundary measurements ,the internal resistivity(or conductivity) distribution of the body can be esti-mated using the boundary voltage based on various re-…  相似文献   

8.
1IntroductionIn recent years , the nonlinear integrable latticeequations have been extensively studied ,such as theAblowitz-Ladik lattice[1], the Toda lattice[2], thedifferential-difference KdVequation[3]and so on[4-7].Inthe theory of nonlinear integrable lattice equations ,ani mportant subject is to search for new Lax integrablelattice equations .In addition,several methods for de-termining exact solutions of soliton equations havebeen developed . The Darboux transformation ( DT)method pl…  相似文献   

9.
Feature extraction of electrocardiogram(ECG) is oneof the mostimportanttasksin heart disease diagnosis .Gen-erally,these algorithms include length and energytransfor-mation[1],hidden Markov models[2],neural networks[3],and wavelet transform[4], etc . Howe…  相似文献   

10.
Study on power systemchaotic phenomena is oneimportant aspect in power system stability stu-dies[1—3]. Early studies, such as Lee[4], Chiang[5],Wang[6]and Tan[7], mainly focused on interpretingthe behavior of chaotic oscillations. Later researches,such as Wu[8], Rajesh[9], Jia[10,11], Srivastava[12]and Abed[13]began to concern the following topics,such as interaction of chaotic motion and system dy-namics, the relationship of power system stability re-gion and chaos, and the methods to eli…  相似文献   

11.
对贝氏体钢的加速腐蚀产物——锈层进行观察和分析,结果表明试验钢的锈层存在两部分:致密的内锈层和疏松的外锈层,内锈层能降低钢的腐蚀速度。试验钢的锈层主要成分是稳定存在的α—FeOOH和Fe3O4,还有少量的γ-FeOOH。  相似文献   

12.
采用射频溅射法在单晶硅基片上沉积了(FE88ZR7B5)0.97CU0.03软磁薄膜样品,对制备态样品进行了直流电流退火处理。结果表明,最佳退火电流为800 MA,在13 MHZ频率下,最大纵向巨磁阻抗比从制备态的8%上升到最佳退火态的17%,明显提高了巨磁阻抗效应和磁场响应灵敏度。详细分析和讨论了样品的巨磁阻抗效应随退火电流变化的特性和机理。  相似文献   

13.
文化结构决定了文化功能实现以及文化的自适应发展模式。同心圆模型把文化划分为由内及外的多个层次,由内到外的层次之间是渐次主导的关系,而由外到内是对这种关系的反应。睡莲模型把同心圆模型中的观念层作了严格区分,以强调“所倡导的”与“所共享的”之间的不一致。目前的文化结构模型都有“把文化分层”的思想,从同心圆模型到睡莲模型,对层次性的强调依次减弱,而对文化系统内部的功能实现机制强调依次上升。不使用“固定层”的概念,而使用“动态块”的概念或许能弥补当前文化层次结构模型的不足。  相似文献   

14.
Plastic pipes reinforced by cross helically wound steel wires (PSP), which have exhibited excellent mechanical performance, consist of inner polyethylene (PE) layer, winding layer and outer PE layer. The winding layer is composed of two monolayers where steel wires are cross helically wound. An analytical procedure is developed to predict the short-term burst pressure of PSP as the monolayer is assumed to be elastic and orthotropic. The 3D anisotropic elasticity and Maximum Stress Failure Criterion are employed in the formulation of the elasticity problem. Good agreement between the theoretical results and the experimental data shows that the proposed approach can well predict the short-term burst pressure of PSP.  相似文献   

15.
利用连续石蜡切片H.E染色技术,对太白山地区淡水涡虫的组织结构进行了观察研究,结果表明:(1)太白山涡虫的体壁外胚层细胞内有明显的杆状体分布;(2)咽壁包括三层结构,外层由单层立方上皮构成,中层分为内侧发达的环肌和外侧较薄的纵肌两部分,内层由单层柱状上皮构成;(3)精巢位于身体两侧,精巢壁主要由各级生精上皮构成,精原细胞、精母细胞、精子细胞及精子散布其中;(4)神经系统为典型的梯式神经系统,前部有蝶状的“脑”,两条纵行神经之间有横神经相连,它们向两侧发出侧神经;(5)根据太白山涡虫各个组织结构特点鉴定为日本三角涡虫。  相似文献   

16.
This study investigates the relative roles of internal and external letter features in word recognition. In Experiment 1 the efficacy of outer word fragments (words with all their horizontal internal features removed) was compared with inner word fragments (words with their outer features removed) as primes in a forward masking paradigm. These forward masked primes were followed by a word to be read aloud. Outer word primes presented for longer durations produced significantly faster naming responses than inner primes. Outer parts of words appear to provide more relevant information for lexical access at an earlier stage than inner fragments. In Experiment 2 words with only external features were named correctly on 96% of occasions compared with 52% of words with only their inner features presented. This indicates much greater information content in the periphery of a word (despite having a reduced area of print available: 45% compared to 55%). Multiple regression analyses controlling for ‘guessability’ (from data in Experiment 2) still produced significantly faster reaction times in the outer relative to the inner priming condition for longer prime durations. These experiments demonstrate that first, the most informative letter features are concentrated in the peripheral region of words; and second, even controlling for this effect, readers appear to have a bias towards analysing outer features of a word before inner features.  相似文献   

17.
Co60.15Fe4.35Sil2,5B15非晶合金进行低频脉冲磁场处理,当脉冲频率固定,脉冲磁场强度为2500e时观察到较大的GMI效应。研究了脉冲磁场作用产生巨磁阻抗的机理:脉冲磁场作用产生的磁致伸缩能降低了非晶合金的形核势垒,使非晶合金得以纳米晶化,进而提高了材料的软磁性能,获得较大的GMI效应。  相似文献   

18.
加磁场退火对铁基薄膜巨磁阻抗效应的影响   总被引:2,自引:0,他引:2  
用射频溅射法制备了(Fe88zr7B5)0.97CU0.03软磁合金薄膜,研究了不同磁场退火方式对(Fe88Zr7B5)0.97 Cu0.03薄膜软磁性能和巨磁阻抗(GMI)效应的影响。结果表明,纵向和横向磁场退火方式都能有效地提高薄膜样品的巨磁阻抗效应,在13 MHz频率下纵向最大GMI比分别为18%和17%;纵向磁场退火能有效消除薄膜样品的磁各向异性,优化薄膜样品的软磁性能;横向磁场退火则能有效感应横向磁各向异性并提高巨磁阻抗效应的磁场响应灵敏度。  相似文献   

19.
Transition metal oxides have been actively exploited for application in lithium ion batteries due to their facile synthesis,high specific capacity,and environmental-friendly.In this paper,Fe_3O_4@TiO_2@C yolk-shell(Y-S) spheres,used as anode material for lithium ion batteries,were successfully fabricated by Stober method.XRD patterns reveal that Fe_3O_4@TiO_2@C Y-S spheres possess a good crystallinity.But the diffraction peaks' intensity of Fe_3O_4 crystals in the composites is much weaker than that of bare Fe_3O_4 spheres,indicating that the outer anatase TiO_2@C layer can cover up the diffraction peaks of inner Fe_3O_4 spheres.The yolk-shell structure of Fe_3O_4@TiO_2@C spheres is further characterized by TEM,HAADFSTEM,and EDS mapping.The yolk-shell structure is good for improving the cycling stability of the inner Fe_3O_4 spheres during lithium ions insertion-extraction processes.When tested at 200 mA/g,the Fe_3O_4@TiO_2@C Y-S spheres can provide a stable discharge capacity of 450 mAh/g over 100 cycles,which is much better than that of bare Fe_3O_4 spheres and TiO_2@C spheres.Furthermore,cyclic voltammetry curves show that the composites have a good cycling stability compared to bare Fe_3O_4 spheres.  相似文献   

20.
“休谟问题”的真正核心在于 :一是内在和外在世界的“流变”性 ,二是这两个世界之间因果作用的非超距性。从这两大核心出发 ,运用拓扑学探讨物体及物体的观念的同一性及二者的时间关系 ,提出了与传统观点根本不同的解答方法  相似文献   

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