摘要:

The disorder produced by 0.3‐MeV D+random bombardment in Si and Ge crystal targets has been investigated with 1.5‐MeV D+channeling measurements. An increase of about 30–50% in the ⟨111⟩‐ and ⟨110⟩‐aligned yields of Ge samples has been found after a bombardment with a dose of 200–300 &mgr;C/cm2. No significant increase was observed in bombarded Si samples. Detailed angular scans suggest a ``spread‐out'' distribution of defects imbedded in the lattice structure.

ISSN:0003-6951    

DOI:10.1063/1.1654441

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The amplifier gain and the energy transmission in Nd‐glass were investigated as functions of light intensity using single picosecond pulses. The observed reductions of gain and transmission are well accounted for by a two‐photon absorption process in the Nd3+system. There is good agreement between the measured and calculated two‐photon absorption cross section of &sgr;′ = (1.3 ± 0.3) × 10−32cm4/W. The two‐photon absorption limits the obtainable output intensity in a Nd‐glass amplifier and reduces the self‐focusing action in the material.

ISSN:0003-6951    

DOI:10.1063/1.1654442

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A new method for measuring velocities and velocity structure functions of turbulence with a single dopplermeter (laser Doppler‐shift velocimeter) is analyzed by optical mixing theory. The zero‐mean‐velocity signal is mixed electronically with a local oscillator before FM demodulation to recover the instantaneous velocity.

ISSN:0003-6951    

DOI:10.1063/1.1654443

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

An electric‐discharge CO‐mixing laser is described in which N2is vibrationally excited in an electrical discharge and then mixed with cold CO in a supersonic expansion providing a population inversion between CO vibrational bands. Continuous output is achieved from an optical cavity established transverse to the flow. Maximum laser power obtained to date is 45 W, corresponding to an efficiency of 4% and a volumetric power density of 6 W/cm3.

ISSN:0003-6951    

DOI:10.1063/1.1654444

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

An optically pumped NH3laser has been used in conjunction with careful doping experiments in high‐purity GaAs to determine the ionization energy of isolated tin donors. The energy obtained is 5.820 meV, which corresponds to a central‐cell correction of 0.081 meV. This technique for impurity analysis is estimated to be sensitive to donor concentrations of less than 1011cm−3.

ISSN:0003-6951    

DOI:10.1063/1.1654445

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

In the power spectra of the scattered light from silver chloride colloidal particles in water, a Lorentzian shifted from zero frequency has been observed in addition to the zero‐centered one. The shifted peak is attributed to the mass motion due to liquid flow resulting from the heating of the illuminated part by the laser beam.

ISSN:0003-6951    

DOI:10.1063/1.1654446

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Bitter's magnetic scanning method was applied to the detection of trace amounts of mercury, using the Zeeman effect of an isotope‐shifted198Hg line. This new technique for trace‐element detection makes it possible to detect Hg in the ppb (part‐per‐billion) range directly from a host material in a few seconds.

ISSN:0003-6951    

DOI:10.1063/1.1654447

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Surface depletion due to surface charges was observed on thin films of silicon on sapphire spinel. A gated metal‐oxide‐semiconductor (MOS) Hall bar structure with a deposited silicon dioxide dielectric was used to determine the true average properties of the films. It is shown that these charges can cause very serious errors in the interpretation of resistivity, Hall coefficient, and mobility data. A decreasing mobility into the films is directly observed.

ISSN:0003-6951    

DOI:10.1063/1.1654448

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The morphology of blisters formed in monocrystalline and polycrystalline niobium samples under 0.5‐MeV4He‐ion impact at 900°C has been studied. For the irradiated monocrystalline samples, the results reveal that the shape and size of the observed blisters are highly dependent on channeling conditions.

ISSN:0003-6951    

DOI:10.1063/1.1654449

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The coercive forces of micron‐sized NdCo5and DiCo5are less than 200 Oe. When these compounds were sintered with Pr&sngbnd;Co and Sm&sngbnd;Co as sintering aids, relatively high coercivities could be obtained. The highest coercivities of sintered NdCo5and DiCo5are 4000 and 10 280 Oe, respectively.

ISSN:0003-6951    

DOI:10.1063/1.1654450

出版商:AIP    

年代:1972

数据来源: AIP