Anisotropic emission of interface fluctuation quantum dots

We calculate energy levels, dipole moments and radiative broadening of interface fluctuation quantum dots. For optically allowed states, the dipole moment grows proportionally to the lateral quantum dot radius while the radiative broadening saturates towards the quantum well radiative broadening for large lateral quantum dot radii. This is accompanied by a change in the angular emission pattern, concentrating emission in forward and backward direction. Optically forbidden states do not couple to light propagating in the growth direction yet they may have a considerable radiative broadening due to spontaneous emission in other directions. Received 20 March 2002 Published online 25 June 2002     

Two types of high-temperature weldable strain gages: Ni−Cr half-bridge filaments and Pt−W half-bridge filaments

The historical development of the single active and “true” (zero gage factor) dummy weldable strain gage is reviewed. The combination of these devices into a half-bridge gage results in transducers capable of static-strain measurements at temperatures of 650 and 950° F for Ni?Cr alloy elements and Pt?W alloy elements, respectively. General application notes concerning these instruments are also included.     

力矩激励器的设计和动态特性

人们愈来愈认识到,机器和其它振动源,向支撑和与之相连接的结构发射的结构声,除了平动成份之外,还有转动成份。众所周知,由于转动分量不易于激发和测量,所以很难对它评价。本文介绍一种由两根平行的磁伸缩棒构成的力矩激励器,并利用一个传递函数来研究它的特性和提出一个物理量一\     

Die Bestimmung der Phosphors?ure und Molybd?ns?ure in phosphor-molybd?nsauren Salzen

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