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61.
Liu Peisheng 《中国有色金属学会会刊》1999,9(3):2
1 INTRODUCTIONHighporositymetalmaterialsarewidelyapplieddailyfortheirspecificcharacteristic[1~5].Asengineeringmaterials,themechanicalpropertiesarebasicforthem[1,3,5].Porousbodiesneedbetensioned,pressed,bentorshapedinsomecases,sohighporositymetalmat… 相似文献
62.
0 INTRODUCTIONIt is known that the diesel particulate emissioncauses serious problems for human health.Exhaustemission regulations for internal combustion engines,especially diesel engines, have become tightened stepby step over the last decades, and hence forced thepace on the development of diesel particulate filters.The traditional technology of reductionparticulate matter from diesel exhaust gas is filtrationby using honeycomb filter made of POrous..di..it.[ l --3]. DePOSited partic… 相似文献
63.
0 INTRODUCTIONMany mechanical systems and structures aremainly linear but contain discrete non-linearities(such as nonlinear shock absorbers, friction inmechanical joints or cracks in shafts). ln some casesthe location of the non-linearity is known, but inmany others the non-linearity develops after thesystem or structure has spent some time in service andits lOcation is not known. As a result, the research onthe location of the discrete non-linearities in mainlylinear systems and structur… 相似文献
65.
1 Introduction Relaxed SiGe layers have gained considerable attention due to their applications in strained Si/SiGe high electron mobility transistor, metal-oxide-semi- conductor field-effect transistor (MOSFET) and other devices. High-quality relaxed SiGe templates, espe- cially those with low threading dislocation density and smooth surface, are crucial for the electrical perform- ance of devices.[1,2] In order to realize high-quality relaxed SiGe layer with such good characteristics, … 相似文献
66.
1 Introduction Spiral computed tomography (CT) was intro- duced in clinical practice in 1980s. Its distinctive characteristic is continuous data acquisition and con- tinuous tube rotation with high speed while simulta- neously translating the patient through the gantry.[1] Owing to these functions the spiral CT possesses the ability to scan an entire organ volume within a single breathhold. Thus, the anatomical section is contiguous and therefore the reliable demonstration of small le- sions… 相似文献
67.
1 Introduction Hepatitis B virus-related liver disease is the most common hepatopathy around the world, especially in developing countries like China, which brings more and more increasing healthy and social burden. To measure liver function accurately is critical for moni-toring the progression of liver dysfunction; evaluating the effect of treatment; predicting long term prognosis and risk of surgical interventions and optimal timing of liver transplant. But in clinic, there are few routine… 相似文献
68.
1IntroductionTheterahertzradiationregimeoftheelectro-magneticwavespectrumisnotwellcoveredbyin-tensesourcesexceptforfewFELfacilities.Abright-nessfarexceedingthatfromablackbodyorsynchro-tronradiationsourcecanbeprovidedbyutilizingfemtosecondelectronbunches.Itcanbeusedforbasicandappliedresearchinmanyfields,suchasmaterialscience,high-Tcmaterials,polymerdynamicsandstructure,biologicalmolecules,phononandsurfacephysics,metrologystandards,etc.[1]Coherentdiffractionradiationisgeneratedbyrelativisticfe… 相似文献
69.
1. IntroductionIntermetallic compound TiAl is expected to be one of the candidates for high temperature systems such as aircraft engines because it has a high specific strength at elevatedtemperatures[1,2]. However, there are two major drawbacks with intermetallic compoundTiAl as an engineering material: one is its poor room temperature ductility and the otheris the poor oxidation resistance above 800xi. The former has been generally overcomeby modification of the microstructure using ternar… 相似文献
70.
XIA Yuebo ZHANG Tianyi State Key Laboratory for Fatigue Fracture of Materials Institute of Metal Research Academia Sinica Shenyang ChinaFEI Guangtao ZHOU Xing Laboratory of Internal Friction Defects in Solids Institute of Solid State Physics Academia Sinica Hefei China Associate Professor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1992,5(6):471-476
The variation of cyclic stress,internal friction and ultrasonic attenuation during cyclicdeformation and relations among them have been investigated with different slip orientationAl single crystals.The results indicate that the value of cyclic stress σ,internal frictionQ~(-1)and ultrasonic attenuation △α depend obviously on the slip orientation.There are largedifferences in above three parameters for different slip orientation Al crystals.In early stageof fatigue life,σ and △α increase and Q~(-1)decreases with cycles N,and △α reached maxi-mum before σ,while Q~(-1)and σ get the valley and the peak,respectively,at same cycles. 相似文献