摘要:

A new process is described which permits the sealing of metals to glass and other insulators at temperatures well below the softening point of the glass. Sealing is accomplished in about 1 min by applying a dc voltage in excess of a few hundred volts between the glass and the metal in such a way that the former is at a negative potential with respect to the latter. The process has been applied to a number of glass‐metal combinations. A discussion is presented of some of the mechanisms which are believed to play a role in the bonding process.

ISSN:0021-8979    

DOI:10.1063/1.1657121

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The solution of the equations representing the shape of an axially symmetric sheet of fluid is given. It is shown that under certain conditions gravity can greatly influence the shape of these sheets (or water bells as they are commonly known). The calculated shape is compared with a photograph of a water bell and it is shown that there is good agreement between the theory and experiment. The effect of gravity on the stability of a water bell is also considered.

ISSN:0021-8979    

DOI:10.1063/1.1657122

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The interaction of laser light with the transparent organic high polymers withQ‐switching dye was investigated. Several sorts of polyalkylmethacrylate plates, for which glass transition temperature was a function of composition of copolymers made of methylmethacrylate andn‐butylmethacrylate, were prepared, and the relationship between the growth rate of the laser‐induced damage and the thermal properties was examined. When the ambient temperature of these copolymer plates was 27°C, the growth rate of the damage becomes slower with the decrement of their glass transition temperature. The authors found that the difference (Tg‐T) or the ratio (Tg/T) of glass transition temperature (Tg) and ambient temperature (T) of the organic high polymers exerts predominant influence on the growth rate of laser‐induced damage.

ISSN:0021-8979    

DOI:10.1063/1.1657123

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Polymer films deposited by electron‐beam bombardment were sandwiched between aluminum electrode films. Photocurrents through these sandwiches, with thicknesses between 150 and 300 Å, were measured in the range of photon energies from 2 to 5 eV and with applied voltage bias up to 3 V. The photocurrent vs bias characteristics are symmetrical about the origin. The photocurrent increases with photon energy at fixed bias, with a threshold photon energy of about 2.2 eV, which is independent of the bias. The optical absorption of the polymer shows approximately the same threshold. These results are discussed in terms of the band structure of amorphous semiconductors.

ISSN:0021-8979    

DOI:10.1063/1.1657124

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The linearity of the reflected shock‐velocity‐particle‐velocity (UR‐up) relationship is probed for some materials that already have a linear fit through their initial shock‐wave data. A pure hydrodynamic theory was used in this investigation with no elastic strength of the material taken into account. Based on the result of this analysis, it is concluded that, for all practical purposes, theUR‐up) relationship is linear and can readily be used to calculate the reflected shock Hugoniot. Explicit forms of both first and second coefficients of the relationship are also given.

ISSN:0021-8979    

DOI:10.1063/1.1657125

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A temperature dependence of the formK=K0exp (−E/kT) has been observed for the rate constants for excitation transfer from the helium metastable atoms to neon. For He(23S)+Ne→He+Ne(2s),K0=3.3×10−11cm3/sec andE=0.051 eV. For He(21S)+Ne→He+Ne(3s),K0=2.1×10−10cm3/sec andE=0.041 eV.

ISSN:0021-8979    

DOI:10.1063/1.1657126

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The change in the pulse repetition frequencyc/2Lof a He&sngbnd;Ne laser, mode‐locked by a neon absorption cell, has been found to vary approximately asI−1/3, whereIis the average power output of the laser. Asc/2Lis changing, the pulse width also changes approximately asI−1/3. The corresponding round trip transit times 2L/care compared to an estimate of the empty cavity transit time obtained by an extrapolation of the data and also a direct measurement. The He&sngbnd;Ne and Ne media introduce an additional positive delay of 4–6 psec to the cavity transit time of 10 nsec; this delay is comparable to that estimated from group velocity considerations.

ISSN:0021-8979    

DOI:10.1063/1.1657127

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A study of a glass laser designed to operate at extremely high power and radiance for possible use in the production of strong shock waves and high‐temperature plasmas is presented. The design makes use of titled face‐pumped disks of neodymium‐doped glass. The advantages and disadvantages of the four proposed ways to use such a laser are considered. To test the disk concept, a system of five 12.5‐cm‐diam, 1.25‐cm‐thick disks was constructed. Design considerations and the results of several measurements with the experimental system are presented. Measurements of the single‐pass gain of the five disks showed a gain coefficient of 0.054/cm, which indicates an energy storage of 0.68 J/cm3, or 100 J per disk.

ISSN:0021-8979    

DOI:10.1063/1.1657128

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A giant pulse ruby laser was used to optically pump a hydrogen gas laser oscillator, operating at the first Stokes‐shifted Raman line at 0.975 &mgr;. Transverse mode control of the high‐Q, curved mirror resonator was provided by controlling the geometry of the pump beam; this allowed operation in the fundamental (TEM00) mode of the cavity. Operating characteristics, including threshold, beam divergence, and spatial and temporal behavior, are discussed.

ISSN:0021-8979    

DOI:10.1063/1.1657129

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The superconducting transition temperature (Tc) variation in the bcc region of the titanium‐niobium‐vanadium ternary system was studied. Cold‐rolled alloys at 10% composition intervals were employed. TheTcvalues were found to vary smoothly with composition. The highest value in the ternary system wasTc=8.8°K for Ti0.6Nb0.3V0.1. The largest decrease in superconducting properties, relative to the Ti binaries, occurred at the first 10% addition of the third element. Additions of Nb to the Ti&sngbnd;V system and of V to the Ti&sngbnd;Nb system led to more sharply defined peaks in theTcversusnrelationship (nstands for the average number of valence electrons per atom) than found in the binaries. TheTcmaximum occurred atn=4.5 for the ternaries with constant vanadium concentration and betweenn=4.4 and 4.5 for constant niobium concentration. The minimum ofTcin the Nb&sngbnd;V system was found to shift towards higher Nb concentrations with increasing content of Ti. TheTcvalues were taken to reflect the density of states at the Fermi surfaceN(0) and their variation was found to be consistent with the rigidd‐band model.

ISSN:0021-8979    

DOI:10.1063/1.1657130

出版商:AIP    

年代:1969

数据来源: AIP