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1.
PREPARATION AND CHARACTERISTICS OF NEW TYPE NANOCOMPOSITE POWDER   总被引:4,自引:0,他引:4  
INTRODUCTIONTheauthor’spastresearchesshowedthatelectroless platedmetal ceramiccompositepow dercouldretardceramicgaingrowthduringthesinterprocess,evenlydispersethemetallicphaseontheceramicmatrixand ,therefore ,in creasethefracturestrength ,toughnessandwear…  相似文献   

2.
INTRODUCTIONInexcavation ,normalanalysisisnotgoodenoughtomeetengineeringneedsduetotheun certaintyofforcesappliedonbracestructures,soilcharacteristics,andsoilmodelused .Toguaranteethattheconstructionprocesscanbesmoothlyperformed ,measurementsinsituareusua…  相似文献   

3.
1 Introduction Withtheincreaseofrequirementsformaterialpropertiesinindustryapplications,suchmaterialswithanisotropicmicrostructuresgetexpansiveapplicotioninindustry[1,2].Directionalsolidificationmicrostructureisoneofthesetypesofmaterials,whichinclud…  相似文献   

4.
Inordertorealizethespecialismofthecompilation ,publicationandissueofa cademicjournalsbymeansofelectronictechniques,promotethenetworkdatascat teringandthedevelopmentofelectronicjournals,expandtheinfluenceofthejournalathomeandabroad ,andincreasetheeffectof…  相似文献   

5.
INTRODUCTIONThequantumstateisanimportantconceptinquantummechanicsandotherrelatedfieldsin cludingquantumoptics,atomoptics,andthephysicsoftrappedparticles.Inrecentyears,peopledevotedmuchtimetoproducevariousquantumstates,andpaidmuchattentiontotheproblemofh…  相似文献   

6.
1 Introduction Inquantumoptics ,somenon classicalstatesoflighthavebeenstudiedrecently .Inparticular ,thoseopticalsuperpositionstates ,whicharebasedontheprincipleofquantumsuperposition ,giverisetovariousnon classicalproperties.Numbersuperpositionstates[1] arep…  相似文献   

7.
Educationalgroupisateaching&learninginstitute ,whichisbroughtforthbythemarketoperationinforeigneducation .Itconveyspositivemeaningintermsofculturaltransportationandaccumulation .Thisarticlefocusesontheorigin ,nature ,characteristics,andinfluenceofforeigne…  相似文献   

8.
1 Introduction Itisknownthattheprotectionefficiencyofzincispartiallyasaresultofformingaprotectivefilmonabasemetal,suchassteel.Althoughpurezinccoatingprovidessomedegreeofprotectionforthesubstrate ,zincisconsumedrapidlyinaseverecorrosionenvi ronment.Conse…  相似文献   

9.
1 Introduction Inordertodetecttoxicgasleakageandtopreventspontaneouscombustionandexplosionofcombustiblegasesandorganicreagent,varioussortsofgassensorshavebeendeveloped,thedevicesthatwerespeciallyusedtodetecttraceoftoxicgasalsohavebeenresearched.Theb…  相似文献   

10.
INTRODUCTIONCommunicativecompetence ,anotionprop osedbyHymes(1 972 )andothersasachallengetoChomsky s (1 965)conceptoflinguisticcom petence,hasnowbecomeaprimarytheoreticalconstructinsociolinguisticsandanumberofre lateddisciplines,especiallyforresearchingintothere…  相似文献   

11.
用平板刚性拘束裂纹试验(PRRC)研究了4种国产低合金高强钢焊接冷裂敏感性,探讨了焊接接头扩散氢含量、焊接线能量、局部预热温度、拘束度的大小及局部预热产生附加应力等对钢材冷裂纹敏感性的影响。建立了国产低合金高强钢的临界冷却时间判据tcr。实验表明此判据可靠,可用于评定现行焊接工艺条件下是否产生冷裂纹及确定合理的焊接工艺。  相似文献   

12.
For the non-conservative holonomic Hamiltonian systems in phase space, the definition and criteria of the form invariance of the generalized Hamilton canonical equations were given. The relations among the form invariance, Noether symmetry and Lie symmetry were studied. The theory of the form invariance for the conservative holonomical systems was worked out. An example was given to illustrate the results.  相似文献   

13.
High frequency ultrasonic nondestructive testing was conducted using a direct contact method for SUS306 stainless steel treated by high temperature and fracture tensile tests. Reflected ultrasonic echoes were analyzed. The relationships between the ultrasonic attenuation coefficient, strength of backscattering wave and the elongation at break of the samples were obtained. The damages were evaluated by using these results together with the analysis of microstructure and mechanics of the tested material. Project supported by the National Natural Science Foundation of China (Grant No.60472102), and the Innovative Program of Shanghai Municipal Education Commission (Grant No.07ZZ03)  相似文献   

14.
A novel asymmetrical pitch system for rotary wing is presented. The pitch control characteristics are studied and analyzed. Because elastic linkage is a key part in whole asymmetrical pitch system, in order to obtain the variation of the elastic linkage deformation, an experimental platform mainly based on the device of micro aerial vehicles (MAVs) and a new control system mounted on TMS320LF2407 are designed. This control system has its compacted configuration and reliability. Finally, using this system to control the MAV for simulating the flying forward, experimental results show the MAV’s flight attitude can be controlled based on the variation of the elastic linkage. Project supported by the National Natural Science Foundation of China (Grant No.60605028), the National High-Technology Research and Development Program of China (Grant No.2007AA04Z225), the Shanghai Rising-Star Program (Grant Nos.07QA14024, 07QH14006), the Shanghai Shuguang Program (Grant No.07SG47), and the Shanghai Leading Key Laboratory of Mechanical Automation and Robotics Science Foundation (Grant No.ZZ0805)  相似文献   

15.
X100管线钢屈服强度在690MPa以上,为了实现钢管埋弧焊缝的高强度高韧性匹配,研制了与X100管线钢相匹配的WS01焊丝,该焊丝匹配大西洋CHF105焊剂,焊接接头抗拉强度810MPa,20℃冲击功,焊缝的弯曲、硬度实验结果均达到AP15L钢管标准要求。  相似文献   

16.
This paper proposes a global stabilization method for a class of planar switched systems with input saturation constrains by using a state feedback and switching strategy. This method is proved to be effective by analyzing the characteristics of the trajectory of second-order linear systems with input saturation. Project supported by the China Postdoctoral Science Foundation (Grant No.20070420643), the National Natural Science Foundation of China (Grant No.60774059), and the Innovation Program of the Shanghai Municipal Science and Technology Commission (Grant No.08DZ2272400)  相似文献   

17.
The nonlinear Riemann problems were converted into nonlinear singular integral equations and the existence of the solution for the problem was proved by means of contract principle.  相似文献   

18.
In this paper, dynamics in the oscillations of the relative atomic population in two periodically driven and weakly coupled Bose-Einstein eondensates (BECs) was qualitatively studied. Using the well-known Melnikov method, the conditions of existence of the periodic and chaotic coherent atomic tunnellings were given in the model. Our results indicate the typical route from bifurcation of the limited circles to chaos, and are in agreement with the previous numerical results.  相似文献   

19.
n-soliton-like solutions of three non-isospectral equations, the non-isospectral mKdV equation, the non-isospectral sine-Gordon equation and the non-isospeetral nonlinear Schroedinger equation were obtained by using the Hirota method.  相似文献   

20.
Single phase Fe5C2 intermetallic compound was prepared by mechanical alloying method. The phase and crystal structure of sample were analyzed with X-ray differaction spectrum. The decomposing temperature of the Fe5C2 compound is 596.4℃ determined by the DSC curve. It is further shown that the size of nanometer crystal grain is an important condition for carrying out the solid state reaction at room temperature and normal pressure.  相似文献   

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