摘要:

The phase‐contrast microscope of Zernike may be scaled in size and combined with ``giant pulse'' ruby‐laser illumination to make possible the observation of macroscopic moving tenuous objects, such as jets, shock waves, and plasmas. The resulting instrument, referred to as the laser phase contrast (LPC) system, has performance similar to that of an optical interferometer operated in the single‐fringe mode. The operation of the LPC system is treated theoretically and conditions for optimum imaging are derived. The ``phase plate'' of Zernike is modified into a ``phase mirror'' for use with focused laser illumination. Quite different mirrors are required for the full range of interesting plasmas accessible to the LPC system. The experimental model is described. Phasograms of weak and strong shocks in air and argon down to 0.5 mm Hg pressure are shown. Rayleigh‐Taylor instability behind the shock is observed. Gas jets of various refractivities are also used as test objects. Phasograms of vacuum sparks producing jets of ablated electrode material are shown. Many objects studied are invisible to schlieren photography using the same illumination and optics.

ISSN:0034-6748    

DOI:10.1063/1.1720602

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

An inexpensive single mirror reflectometer for specular reflectivity studies at nearly normal incidence is described. This design minimizes errors in the reflectivity which may occur as a result of spatial variations in both the detector sensitivity and the mirror reflectivity. The reflectometer has been successfully used for reflectivity measurements from 2 to 22 eV in a detector‐sample chamber which is coupled to a McPherson vacuum ultraviolet monochromator.

ISSN:0034-6748    

DOI:10.1063/1.1720603

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A thermal gradient apparatus for use in a plutonium glovebox is described. Axial gradients of 1000 C°/cm have been maintained in oxide samples for continuous periods of time in excess of 500 hours with this furnace. The system is operable in inert atmospheres or high vacuum.

ISSN:0034-6748    

DOI:10.1063/1.1720604

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The construction and calibration of a rotational displacement transducer, using light sensitive resistors and a variable slit, are described. The instrument is capable of measuring both static and dynamic angular displacements and has a continuous range of sensitivity with a resolution as low as 0.01°. The linearity of the response over a 50° linear region is within 1% of the full scale deflection of 135°. The transducer exhibits no substantial phase lag and has response well suited for low frequency oscillation studies in the range 0–50 cps. The device is light in weight and has free undamped motion due to an external air‐bearing suspension system. A restriction which must be noted in applying the transducer is that because of high frequency response dropoff the instrument is suitable only for recording accurately low frequency angular displacements of quasiharmonic waveform.

ISSN:0034-6748    

DOI:10.1063/1.1720605

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Design of a high‐temperature furnace and sample cell for measuring the small‐angle x‐ray scattering of liquids or solids with the Kratky camera is reported. The cell may be used to 750°C with constancy of ±0.05 C°; a crucible for charging liquid metal mixtures into the cellin situunder inert atmospheres is also described.

ISSN:0034-6748    

DOI:10.1063/1.1720606

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The electroluminescent panel can be used as a linear modulatable light source at audio frequencies. (Brightness vs voltage linearity is extremely good for modulation as high as 60%.) Linear operation is accomplished by operating the panels at three times the normal voltage with a carrier frequency of 10 kHz. The rapid aging and resultant light loss which normally accompanies operation under these conditions is eliminated through the use of an efficient heat sink.

ISSN:0034-6748    

DOI:10.1063/1.1720607

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The behavior of standing wave accelerator tanks, made up of chains of resonant cavities, is investigated using a coupled resonator model. This model gives accurate predictions of the behavior of such a cavity chain, including tolerances to errors in manufacture, cavity feed distributions, and transient response. The parameters necessary in the theory, the cavity couplings, Q's, and frequencies, may easily be determined by experiment. Extension of the simple chain to a more complex chain with double periodicity and second nearest neighbor coupling is demonstrated. Advantages of operating such accelerators in the &pgr;/2 mode are shown.

ISSN:0034-6748    

DOI:10.1063/1.1720608

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A regenerative autodyne wired as a cathode biased grid‐dip‐meter is equal to Wang's spectrometer [Phys. Rev.99, 566 (1955)] in sensitivity and far superior in reliability. Detailed description of an autodyne used in chlorine NQR is presented.

ISSN:0034-6748    

DOI:10.1063/1.1720609

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

The crushing strength of various models of cemented tungsten carbide pistons has been determined as a function of the ratio of unconstrained length to diameter (L/D). There was little effect for pistons whose ends were unsupported, but a dramatic increase in crushing strength with decreasingL/Dfor pistons whose ends were supplied with interference‐fitted binding rings. Tests with pistons of different diameter but constantL/Dsuggest the absence of any effects dependent on the diameter of the pistons.

ISSN:0034-6748    

DOI:10.1063/1.1720610

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A simple, inexpensive, two‐channel gated (``boxcar'') integrator circuit using solid state components is described. Features of the circuit include a wide range of usable gate widths (from 0.2 &mgr;sec to arbitrarily large), a wide range of learning times (0.05 &mgr;sec to 1 sec), a high ratio of holding to learning time (as high as 4×107for 1% output voltage sag), linearity of about 0.3% over a range of ±8 V at the output, temperature stability of about 3.5 mV/C° at the output, and a long term drift of about 0.5 mV/h at the output.

ISSN:0034-6748    

DOI:10.1063/1.1720611

出版商:AIP    

年代:1967

数据来源: AIP