摘要:

Some new orientations and propagation directions possessing zero temperature coefficients of delay for surface waves in quartz with somewhat better electromechanical coupling than the ST cut are reported. One of the orientations also exhibits an almost‐zero power flow angle. The results have been obtained using a nonlinearly based formalism in which the reference geometry, which remains fixed as the temperature is varied, may be employed.

ISSN:0003-6951    

DOI:10.1063/1.90693

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A new sector‐scan imaging device with moving focus is reported. This device uses an analog calculator for generating the scanning acoustic beam in place of the digital calculator needed in some other designs. It allows series or parallel operation in the imaging process. The basic principle and some preliminary results on the analog calculator operation and on imaging applications are shown.

ISSN:0003-6951    

DOI:10.1063/1.90694

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The thermally stimulated current (TSC) has been used over a wide range of pressure to determine the principal characteristics of the polymers such as the activation volume &Dgr;V, the activation energy &Dgr;E, and the preexponential term &tgr;0of the Arrhenius‐type relaxation time: &tgr;=&tgr;0 exp[(P&Dgr;V+&Dgr;E)/kT]. Experimentally, the 6‐Polyamide sample is subjected to a high hydrostatic pressure before application of the classical TSC method. The variation law of the relaxation time, a function of temperature and pressure, &tgr; (P,T), of this polymer is given by the determination of these characteristics with the initial slope analysis of the TSC experimental curves.

ISSN:0003-6951    

DOI:10.1063/1.90695

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The observation of planar long‐antenna coupling to a metal‐oxide‐metal (edge configuration) has been demonstrated at &lgr;=118 &mgr;m. The two major lobes of an 11&lgr; antenna are coupled to via a superstrate prism. Insufficient data is presently available to identify with certainty the mechanism of detection.

ISSN:0003-6951    

DOI:10.1063/1.90696

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The use of solid pellets of hydrogen isotopes to refuel thermonuclear fusion reactors based on the tokamak configuration will require that the pellets be accelerated to high velocities. One possible method of acceleration is to interact a fast plasma from a plasma gun with the pellets. In this paper preliminary results are given on the acceleration of solid pellets with a plasma gun. The plasma‐gun requirements for successful acceleration to high velocities are discussed.

ISSN:0003-6951    

DOI:10.1063/1.90697

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Piezoelectric polymers, such as PVF2, being light and flexible, are attractive new materials for transducers. A new all‐electrical meaurement method for piezoelectric parameters of PVF2has been developed. Moreover, the method permits application of a variable bias field going to high values in addition to the small alternating field used for measurement. By using this technique, it has been found that linear performance extends to a very high electric field (30 V/&mgr;m) without degradation. This technique is also used to study the behavior ofd31under a range of dc field strengths. Finally, the method is used to investigated various procedures for poling PVF2.

ISSN:0003-6951    

DOI:10.1063/1.90698

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A polycrystalline silicon film 0.55 &mgr;m thick was deposited in a low‐pressure CVD reactor on a Si3N4substrate. Islands of various sizes (2×20 &mgr;m up to 20×160 &mgr;m) were prepared by standard photolithographic techniques. Laser annealing was then performed under conditions which are known to cause an increase in grain size from ∼500 A˚ to long narrow crystals of 2×25 &mgr;m in a continuous polysilicon film. These same conditions were found to produce single‐crystal ⟨100⟩ material in the (2×20 &mgr;m) islands. However, 25×25‐&mgr;m and 20×160‐&mgr;m islands remain polycrystalline after the laser scan.

ISSN:0003-6951    

DOI:10.1063/1.90699

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

This report outlines the growth of highly transparent films of undoped tin oxide at near ambient temperatures (∼30 °C). Films were deposited by a technique based on the reaction of rf plasma‐activated oxygen with tetramethyltin. Growth rates as high as 160 A˚/min have been achieved with a 100‐&mgr;m partial pressure of tetramethyltin and an overall system pressure of 500 &mgr;m. The growth kinetics have been explained by a model in which the tetramethyltin is the rate limiter, and the concentration of active oxygen is independent of the flow rate of molecular oxygen.

ISSN:0003-6951    

DOI:10.1063/1.90683

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

(Ga,Al)As lasers were employed to optically machine a series of 1‐&mgr;m‐diam holes in 200–300‐A˚‐thick films of tellurium on polymethylmethacrylate substrates at repetition rates as high as 10 MHz. By modulating the hole repetition frequency, limited bandwidth video signals were successfully recorded. The hole machining was accomplished with lasers which operated in fundamental transverse and lateral mode at high pulsed power (typically greater than 150 mW), in conjunction with a high‐collection‐efficiency focusing system. The lasers were operated at low (⩽20%) duty cycle in order to minimize internal heating. The hole sizes obtained and the repetition rates achieved are appropriate for a high‐density optical recording system.

ISSN:0003-6951    

DOI:10.1063/1.90684

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Efficient stimulated Raman scattering (SRS) has recently been achieved in lithium iodate (LiIO3) at kHz PRF’s, thereby producing substantial average output powers in the first and second Stokes lines. In this letter, we show that the same LiIO3crystal that serves as the Raman medium can also be used to generate the second harmonics and sum frequencies of the pump and Stokes lines. By rotating a LiIO3crystal placed inside a Nd : YAlO3laser, we have successively generated phase‐matched outputs at 0.54 &mgr;m (1.13 W), 0.565 &mgr;m (78 mW), 0.592 &mgr;m (685 mW), 0.622 &mgr;m (98 mW), and 0.655 &mgr;m (107 mW).

ISSN:0003-6951    

DOI:10.1063/1.90685

出版商:AIP    

年代:1979

数据来源: AIP