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1 Jul 1978

Volume 49, Issue 7, pp. 3645-4303

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Prediction of catastrophes in bistable systems using externally applied random force

Masahiro Agu and Yasuaki Teramachi

J. Appl. Phys. 49, 3645 (1978); http://dx.doi.org/10.1063/1.325414 (4 pages) | Cited 4 times

Online Publication Date: 12 August 2008

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A method is proposed to forecast the catastrophic changes of the states of bistable systems with the use of externally applied Gaussian random force. The prediction is based on the fact that the probability distribution function of the states of a bistable system under the influence of Gaussian random force becomes far from Gaussian in the vicinity of its catastrophe. In other words, the anomalous increase of the variance of the probability distribution function in the vicinity of the catastrophe can be utilized as a precursory phenomenon to predict the catastrophe. The anomaly of the probability distribution function is caused by the nonlinear property of the bistable system.
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05.70.Jk Critical point phenomena
05.70.Fh Phase transitions: general studies

Transfer of energy from charged transmission lines with applications to pulsed high‐current accelerators

D. Eccleshall and J. K. Temperley

J. Appl. Phys. 49, 3649 (1978); http://dx.doi.org/10.1063/1.325415 (7 pages) | Cited 5 times

Online Publication Date: 12 August 2008

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An analysis has been performed of charged transmission‐line configurations for use in high‐current electron accelerators. Conditions for maximum efficiency and maximum energy transfer to the beam load are derived for ideal constant‐impedance lines. It is shown that, in the lossless‐line approximation, asymmetric line‐pair configurations exist with which both a high accelerating voltage and nominal 100% efficiency can be achieved. The configurations would also have application as a pulse‐forming network for use with other switched loads.
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29.20.Ej Linear accelerators
84.40.Az Waveguides, transmission lines, striplines

Neutral‐beam divergence due to imperfect magnetic shielding

J. R. Conrad

J. Appl. Phys. 49, 3656 (1978); http://dx.doi.org/10.1063/1.325416 (6 pages) | Cited 3 times

Online Publication Date: 12 August 2008

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The divergence of a neutral beam due to imperfect magnetic shielding of the gas‐cell neutralizer is considered. Coupled kinetic equations for the ion and neutral velocity distribution functions are solved. The deflection and divergence of the neutral beam are obtained from moments of the neutral distribution function.
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29.25.Lg Ion sources: polarized
29.25.Ni Ion sources: positive and negative
51.10.+y Kinetic and transport theory of gases
29.27.Eg Beam handling; beam transport
28.52.-s Fusion reactors

Laser‐induced dichroism and birefringence in two‐ and three‐level systems of neon

C. Delsart and J.‐C. Keller

J. Appl. Phys. 49, 3662 (1978); http://dx.doi.org/10.1063/1.325417 (5 pages) | Cited 8 times

Online Publication Date: 12 August 2008

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We have observed the Doppler‐free dichroism and birefringence induced by a linearly polarized laser beam (pump beam) by monitoring the polarization and amplitude changes of a weak probe beam through an analyzer. The effects have been observed in two‐level systems and also in three‐level systems of Ne I. At rather low pump power, a typical refractive‐index anisotropy of 10−8 has been measured. We have shown that, when the normal resonance curve exhibits a broad background due to collisions, our method allows the elimination of this background. In addition, using a rotating analyzer, we have obtained simultaneously the dichroism and birefringence curves, i.e., the imaginary and real part of the anisotropic‐induced susceptibility.
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32.90.+a Other topics in atomic properties and interactions of atoms with photons (restricted to new topics in section 32)
07.77.-n Atomic, molecular, and charged-particle sources and detectors
37.20.+j Atomic and molecular beam sources and techniques
42.25.Lc Birefringence
51.70.+f Optical and dielectric properties

Analysis of the repetitively pulsed dual‐beam thermo‐optical absorption spectrometer

Robert L. Swofford and James A. Morrell

J. Appl. Phys. 49, 3667 (1978); http://dx.doi.org/10.1063/1.325418 (8 pages) | Cited 34 times

Online Publication Date: 12 August 2008

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An analysis is presented for the repetitively pulsed dual‐beam thermo‐optical absorption spectrometer, which has been used recently to determine the absorption strengths of several organic liquids in the visible spectral region covered by the cw tunable dye laser. The model succeeds in describing the development of the thermal lens on a pulse‐by‐pulse basis. The equations derived are then used to optimize the spectrometer design with respect to the parameters which are under the control of the experimenter. It is further demonstrated how one identifies the region of linear operation of the spectrometer. Finally, it is shown how the relative absorptivities of compounds may be determined.
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33.20.Kf Visible spectra
07.77.-n Atomic, molecular, and charged-particle sources and detectors
37.20.+j Atomic and molecular beam sources and techniques
78.20.N- Thermo-optic effects
78.20.nb Photothermal effects
78.40.Dw Liquids

Self‐magnetic insulation in vacuum for coaxial geometry

S. Shope, J. W. Poukey, K. D. Bergeron, D. H. McDaniel, A. J. Toepfer, and J. P. VanDevender

J. Appl. Phys. 49, 3675 (1978); http://dx.doi.org/10.1063/1.325419 (4 pages) | Cited 23 times

Online Publication Date: 12 August 2008

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Magnetic insulation obtained by employing the magnetic field of the line current in coaxial vacuum‐transmission lines is studied in experiments on two different relativistic electron‐beam accelerators, spanning the voltage range 0.4–10 MV. Effective magnetic insulation at fields up to 1.3 MV/cm is demonstrated. The self‐limiting impedance is measured and compared to a number of theories for magnetic insulation and it is found that none of the ’’standard’’ theories successfully describes the data. However, computer simulations using a self‐consistent two‐dimensional particle code give good agreement with the experimental data, as does a proposed modification of the parapotential flow model.
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41.75.Fr Electron and positron beams
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables
29.20.Ej Linear accelerators

Long‐lived lead‐vapor lasers

D. W. Feldman, C. S. Liu, J. L. Pack, and L. A. Weaver

J. Appl. Phys. 49, 3679 (1978); http://dx.doi.org/10.1063/1.325420 (5 pages) | Cited 3 times

Online Publication Date: 12 August 2008

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Lead‐laser operation has been demonstrated at 7229 Å in all‐hot sealed‐off quartz discharge tubes for 50‐h cumulative operating times without tube degradation or failure. The maximum output energy of 230 μJ or 2.0 μJ cm−3 was obtained at ∼1.5 kHz, and the discharge efficiency was 0.12%. Average‐power levels of 750 mW at 6 kHz were maintained under burst mode excitation conditions for extended periods at temperatures of ∼1050 °C. Lead‐laser emission at ∼500 °C was also obtained using lead iodide as the starting material.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers

Room‐temperature threshold‐current dependence of GaAs‐AlxGa1−xAs double‐heterostructure lasers on x and active‐layer thickness

H. C. Casey

J. Appl. Phys. 49, 3684 (1978); http://dx.doi.org/10.1063/1.325421 (9 pages) | Cited 77 times

Online Publication Date: 12 August 2008

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The known properties of GaAs and AlxGa1−xAs have been used to calculate the threshold‐current density of double‐heterostructure (DH) lasers at room temperature without adjustable parameters. In the absence of leakage currents due to unconfined carriers, the room‐temperature threshold‐current density for broad‐area DH lasers may be repesented by Jth (A/cm2) =4.5×103d+(20d/Γ)[αi+(1/L)  ln(1/R)], where d is the active‐layer thickness in microns, Γ is the waveguide confinement factor, αi is the internal loss, L is the cavity length, and R is the facet reflectivity. The experimentally observed increase of Jth for x<0.2 given by Rode is shown to be due to the diffusive electron and hole leakage currents, and a best fit to the data was obtained with an electron minority‐carrier diffusion length in AlxGa1−xAs (x≲0.3) of ∼1 μm. The above expression for Jth fits Kressel and Ettenberg’s Jth versus active‐layer‐thickness data at x=0.65, while for x=0.3, the experimental Jth is 300 A/cm2 larger than the calculated Jth at d=0.1 μm. This difference appears to be due to greater scattering loss at x=0.3 than x=0.6.
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42.55.Px Semiconductor lasers; laser diodes

Optical properties in titanium‐diffused LiNbO3 strip waveguides

Masaharu Fukuma, Juichi Noda, and Hiroshi Iwasaki

J. Appl. Phys. 49, 3693 (1978); http://dx.doi.org/10.1063/1.325409 (6 pages) | Cited 49 times

Online Publication Date: 12 August 2008

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Optical insertion losses in embedded strip waveguides fabricated in LiNbO3 by Ti diffusion have been examined at a 0.633‐μm wavelength, taking into account resultant near‐field patterns. It is confirmed that the main factors influencing optical insertion losses are radiation loss by the deficient refractive‐index change of a waveguide, scattering loss by insufficient diffused residual titanium oxide film on a waveguide, and coupling loss between a waveguide and a fiber. A diffusion condition for making a low‐loss waveguide is presented, although suppression of lateral diffusion is necessary to achieve further insertion‐loss reduction.
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42.79.Gn Optical waveguides and couplers
66.30.J- Diffusion of impurities

Self‐focusing and defocusing of pump radiation in a far‐infrared laser

M. R. Siegrist, P. D. Morgan, and M. R. Green

J. Appl. Phys. 49, 3699 (1978); http://dx.doi.org/10.1063/1.325410 (4 pages) | Cited 9 times

Online Publication Date: 12 August 2008

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For optically pumped FIR lasers the frequency of the pump beam is in close coincidence with an absorbing transition of the active medium. Saturable absorption results in an intensity‐dependent local refractive index, leading to self‐focusing or defocusing. The latter effect has been demonstrated experimentally in CH3F, in which a beam divergence of the order of several mrad was measured, in agreement with theoretical predictions. This phenomenon has important consequences in the design of high‐power FIR amplifiers.
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42.60.By Design of specific laser systems
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.55.Lt Gas lasers including excimer and metal-vapor lasers

Relationship between fiber tension and drawing velocity and their influence on the ultimate strength of laser‐drawn silica fibers

H. Schonhorn, H. N. Vazirani, and H. L. Frisch

J. Appl. Phys. 49, 3703 (1978); http://dx.doi.org/10.1063/1.325411 (4 pages) | Cited 4 times

Online Publication Date: 12 August 2008

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The ultimate strength of laser‐drawn silica fibers has been found to be related to the velocity of drawing and the tension in the fiber required to maintain it. We find that when the uncoated pristine fiber tension during drawing exceeds about 80 g for a 110‐μm fiber there is a dramatic decrease in strength (coated fiber). Dimensional analysis of the laser‐drawing process indicates that for this particular system the fiber tension should be proportional to the cube of the drawing velocity. This is confirmed experimentally for fibers drawn at a variety of tensions and speeds of 0.4 and 1.0 m/s.
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42.81.-i Fiber optics
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
46.50.+a Fracture mechanics, fatigue and cracks
42.60.-v Laser optical systems: design and operation

Effect of nonlinear absorption on self‐focusing of a laser beam in a plasma

M. S. Sodha, L. A. Patel, and R. P. Sharma

J. Appl. Phys. 49, 3707 (1978); http://dx.doi.org/10.1063/1.325412 (7 pages) | Cited 11 times

Online Publication Date: 12 August 2008

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Considering both the real and imaginary parts of the dielectric constant to be intensity dependent, we have investigated the self‐focusing of a Gaussian laser beam in a plasma. The mechanism or nonlinearity considered herein is the ponderomotive force or heating mainly determined by collisions of electrons with heavier particles. An equation for the beamwidth parameter and an expression of the axial intensity have been obtained in the WKB(J) and paraxial approximations. It is seen that the effect of nonlinear absorption on self‐focusing is significant. Consideration of nonlinearity in absorption predicts focusing of a laser beam (under certain conditions) even when the linear‐absorption approximation would predict defocusing of the beam. The results reduce to the corresponding analytical results reported earlier, when the intensity dependence of the dielectric constant is neglected. The technique adopted in the present investigation for solving the wave equation in the presence of nonlinear absorption is equally applicable to media other than a plasma.
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42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma

Gain measurements on the sequence bands in a TEA‐CO2 amplifier

P. Lavigne, J.‐L. Lachambre, and G. Otis

J. Appl. Phys. 49, 3714 (1978); http://dx.doi.org/10.1063/1.325413 (5 pages) | Cited 4 times

Online Publication Date: 12 August 2008

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Small‐signal gains as high as 1.5% cm−1 have been measured in a TEA‐CO2 amplifier on the 00°2‐ (1001, 0201)I,II sequence bands. The ratio of the gain coefficient of the sequence bands over the gain coefficient of the regular bands has been observed to be independent of either the CO2 or He proportion in the gas mixture. It has also been found to increase with the electrical energy dumped into the active medium and to reach a value of 1/3 at an excitation density of 140 J/l. Gain on the sequence bands has been found to be responsible for the anomalously high gain coefficient that is measured at low J values of the R branch of the regular 9.4‐μm transition in TEA amplifiers.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers

Electrical characterization of heterostructure lasers

W. B. Joyce and R. W. Dixon

J. Appl. Phys. 49, 3719 (1978); http://dx.doi.org/10.1063/1.325422 (10 pages) | Cited 30 times

Online Publication Date: 12 August 2008

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An improved phenomenological model of the electrical and optical characteristics of semiconductor heterostructure injection lasers is analyzed with emphasis on the nonlasing‐to‐lasing phase transition. The model includes both radiative and nonradiative carrier recombination, as well as electron‐photon coupling. Recently developed approximations of the Fermi‐Dirac integral are used, and they allow closed‐form solutions of the electron and photon rate equations to be obtained—even though the carrier populations are highly degenerate near lasing threshold. Because of the detailed information which harmonic‐voltage amplitudes provide, calculation of the functional forms of the voltage derivatives of the devices is emphasized, and expressions for the height and width of the second‐derivative peak, and for the slope at threshold of the first derivative, are obtained. The effects of carrier degeneracy and of nonradiative recombination are explicitly displayed, and both are found to be important in modifying the values of the parameters entering the traditional form, i=ir exp(qV/mkT), of the forward‐conduction current‐voltage relation. In (Al,Ga)As stripe‐geometry lasers values of m?2 are found to be reasonable.
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42.55.Px Semiconductor lasers; laser diodes
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Sensitive F2 absorption diagnostic

Donald J. Spencer

J. Appl. Phys. 49, 3729 (1978); http://dx.doi.org/10.1063/1.325423 (4 pages) | Cited 4 times

Online Publication Date: 12 August 2008

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A sensitive F2 absorption diagnostic technique was developed by which a difference in absorption sensitivity of ΔI/I0=10−4 can be determined. This value corresponds to an F2 pressure–path‐length product of 0.215 Torr cm at 300 K. The method was applied to an HF (DF) chemical laser flow and resulted in measured average nozzle‐exit values (α) of from 0.4 to 0.5 from a totally dissociated plenum, indicating a large degree of nozzle wall recombination.
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42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
78.60.Ps Chemiluminescence
42.55.Ks Chemical lasers
42.60.Fc Modulation, tuning, and mode locking

F2 absorption measurement in a combustion‐driven chemical‐laser nozzle

Donald J. Spencer and Charles W. Clendening

J. Appl. Phys. 49, 3733 (1978); http://dx.doi.org/10.1063/1.325424 (4 pages)

Online Publication Date: 12 August 2008

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A sensitive F2 absorption diagnostic technique was used to determine F2 densities in the flow of a 10.2‐cm‐long combustion‐driven chemical‐laser nozzle. The diagnostic device was demonstrated to be readily transportable and operable in a combustion‐driven chemical‐laser field environment. Cold‐ and hot‐flow measurements up to 970 K plenum temperature (i.e., no F2 dissociation cases) were in agreement; hence, the measurement technique appears to be reliable. The use of C2H4 as a combustor fuel did not result in particulate absorption or scattering of sufficient magnitude to affect the measurement. The flow dissociation level (α) was ≳0.8 for this nozzle. The measurement sensitivity achieved in these tests was ΔI/I0=6×10−4, which corresponds to an F2 density of 6.76×10−6 mole/l (i.e., 0.127 Torr F2 at 300 K) for a 10.2‐cm path length.
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42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
78.60.Ps Chemiluminescence
42.55.Ks Chemical lasers
42.60.Fc Modulation, tuning, and mode locking

Single‐crystal CdTe with low absorption at 10.6 μm for use as ir laser windows

F. A. Selim and F. A. Kroger

J. Appl. Phys. 49, 3737 (1978); http://dx.doi.org/10.1063/1.325425 (5 pages) | Cited 1 time

Online Publication Date: 12 August 2008

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Optimum conditions for the preparation of CdTe with minimum absorption at 10.6 μm are determined, paying attention both to type and concentration of dopants and the conditions of annealing. Doping with indium and annealing at 700 °C followed by quenching led to material with the smallest absorption coefficient at 10.6 μm of 8×10−4 cm−1.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
72.80.Ey III-V and II-VI semiconductors
78.30.Hv Other nonmetallic inorganics
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Studies of a small‐gap multiatmospheric‐pressure CO2 laser

T. Carman and P. E. Dyer

J. Appl. Phys. 49, 3742 (1978); http://dx.doi.org/10.1063/1.325426 (5 pages) | Cited 11 times

Online Publication Date: 12 August 2008

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A 4‐mm gap uv preionized CO2 laser has been developed, which operates at pressures ≲ 12 atm using relatively low voltages. Studies of the small‐signal gain and laser‐performance characteristics are reported.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
52.80.-s Electric discharges

Mirror‐damage thresholds for laser‐fusion pulse shapes

James E. Howard and T. O. Hunter

J. Appl. Phys. 49, 3747 (1978); http://dx.doi.org/10.1063/1.325427 (3 pages)

Online Publication Date: 12 August 2008

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Mirror‐surface‐damage thresholds are calculated analytically for two temporal pulse forms relevant to laser‐fusion experiments; a truncated Gaussian and the ’’ideal’’ isentropic pulse. The results show that 20% more laser energy/cm2 may be handled using a two e‐folding Gaussian of the same FWHM as a square pulse of equal peak power. The surface‐temperature rise is given in completely closed form for the isentropic pulse and applied to a conceptual laser‐fusion design.
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42.62.-b Laser applications
42.15.Eq Optical system design
42.79.Bh Lenses, prisms and mirrors
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
79.20.Ds Laser-beam impact phenomena

Enhancement of NF(b1Σ+) by iodine laser pumping

J. M. Herbelin, M. A. Kwok, and D. J. Spencer

J. Appl. Phys. 49, 3750 (1978); http://dx.doi.org/10.1063/1.325428 (3 pages) | Cited 6 times

Online Publication Date: 12 August 2008

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A peak density of electronically excited free radical NF(b1Σ+) of 5.6×10−10 mol/cm3 has been produced in a subsonic flow by means of intracavity pulsed iodine laser pumping of ground‐state iodine atoms and subsequent energy transfer of this electronic energy to NF(a1Δ) free radicals. This concentration represents a 30‐fold increase over previously reported steady‐state concentrations and supports the promise of the NF(b1Σ+) species as a potential laser candidate.
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42.55.-f Lasers
47.70.-n Reactive and radiative flows
51.70.+f Optical and dielectric properties
82.20.Rp State to state energy transfer

Laser generation by pulsed 2.45‐GHz microwave excitation of CO2

K. G. Handy and J. E. Brandelik

J. Appl. Phys. 49, 3753 (1978); http://dx.doi.org/10.1063/1.325429 (4 pages) | Cited 9 times

Online Publication Date: 12 August 2008

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A small CO2‐N2‐He laser excited by a pulsed microwave source at 2.45 GHz has been operated at low powers. Microwave power flux density was increased by using tapered sections to modify the aspect ratio. Pulsed microwave excitation of the gases resulted in laser output pulses characterized by time delays to threshold and long pulse lengths. The efficiency of conversion of microwave energy to laser energy was over 4%.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
52.80.Pi High-frequency and RF discharges

Transfer function for an acoustic source‐receiver and target in a homogeneous fluid with distant boundaries

D. H. Hageman

J. Appl. Phys. 49, 3757 (1978); http://dx.doi.org/10.1063/1.325430 (12 pages)

Online Publication Date: 12 August 2008

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The transfer function of the title is derived first for the case of a stationary source‐receiver and a stationary target, with each in the far field of the other. Then, a quasi‐transfer‐function is constructed for the case in which the two bodies, separated as before, are moving at speeds which are small relative to the speed of sound, the flow around them being assumed to be derivable from velocity potentials. In both cases, the problem is formulated in terms of Helmholtz‐Kirchhoff integrals. Conditions related to the distance to boundaries are deduced through the method of images. Theorems due to Blokhintsev and Oestreicher are used to treat the radiation, scattering, and reception of sound by a moving body.
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43.30.Vh Active sonar systems
43.20.Fn Scattering of acoustic waves
43.60.-c Acoustic signal processing

A model for multitrack nonperiodic multistrip couplers

Supriyo Datta and Bill J. Hunsinger

J. Appl. Phys. 49, 3769 (1978); http://dx.doi.org/10.1063/1.325431 (5 pages) | Cited 2 times

Online Publication Date: 12 August 2008

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A simple circuit model for the multistrip coupler is presented. The transmission matrix of a single strip relating the output‐ and input‐wave amplitudes in different tracks is obtained from circuit theory. The overall transmission matrix of the coupler is obtained by cascading the transmission matrices of successive strips. The model is shown to yield the correct results for common coupler configurations. This model because of its strip‐by‐strip approach makes it straightforward to analyze nonperiodic couplers which are difficult to analyze by usual techniques. Numerical solutions for a strip‐coupled UDT are presented in agreement with previous experimental results.
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43.38.+n Transduction; acoustical devices for the generation and reproduction of sound
41.20.Jb Electromagnetic wave propagation; radiowave propagation

Time‐dependent crack propagation in linear‐elastic solids

A. S. Krausz

J. Appl. Phys. 49, 3774 (1978); http://dx.doi.org/10.1063/1.325432 (5 pages) | Cited 6 times

Online Publication Date: 12 August 2008

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See Also: Erratum

Show Abstract
Simple rigid crack‐front propagation and the mechanism of double‐kink nucleation and spreading are analyzed in a periodic crystallographic potential‐energy field. For the analysis the classical Griffith model for crack propagation is superposed on the periodic energy field of the crystal lattice. The energy‐condition theory of the time‐dependent crack propagation is developed in terms of the absolute rate theory. A complete kinetics analysis is carried out for the description of the rigid and kinked crack‐front propagation rate over the consecutive energy‐barrier system of the crystal lattice. The rate is expressed as a function of the applied stress, temperature, the free energy of fracture, and the lattice parameters.
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46.50.+a Fracture mechanics, fatigue and cracks
62.20.M- Structural failure of materials
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure

Crack propagation in alkaline‐earth fluorides

P. F. Becher and S. W. Freiman

J. Appl. Phys. 49, 3779 (1978); http://dx.doi.org/10.1063/1.325433 (5 pages) | Cited 12 times

Online Publication Date: 12 August 2008

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The fracture of CaF2, SrF2, and BaF2 crystals by {111} cleavage requires critical fracture energies (γIC) which increase with decrease in cation size, as would be predicted. The γIC of single crystals, however, can be affected by the crystallographic direction of crack propagation and by annealing treatment. The introduction of grain boundaries can also result in some increase in γIC, particularly for finer grain sizes. Slow crack growth, which is sensitive to the environment, is observed but differs from that noted in other brittle materials in that it is often accompanied by crack arrest. This observation, as well as the stair‐step crack motion during slow crack growth in concentrated HF, indicates that dislocation motion at the crack tip is associated with the slow‐crack‐growth phenomenon. Because of the extremely strong influence of the stress intensity on crack growth velocity, the effects of delayed failure should be minimal in CaF2, SrF2, and BaF2.
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46.50.+a Fracture mechanics, fatigue and cracks
62.20.M- Structural failure of materials
42.79.Fm Reflectors, beam splitters, and deflectors
42.79.Ls Scanners, image intensifiers, and image converters
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
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