ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Digitale Medien

Lattice instability at a fast moving crack tip (1996)

Zhang, Y. W. ; Wang, T. C.

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 80 (1996), S. 4332-4336

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: A molecular dynamics method is used to analyze the dynamic propagation of an atomistic crack tip. The simulation shows that the crack propagates at a relatively constant global velocity which is well below the Rayleigh wave velocity. However the local propagation velocity oscillates violently, and it is limited by the longitudinal wave velocity. The crack velocity oscillation is caused by a repeated process of crack tip blunting and sharpening. When the crack tip opening displacement exceeds a certain critical value, a lattice instability takes place and results in dislocation emissions from the crack tip. Based on this concept, a criterion for dislocation emission from a moving crack tip is proposed. The simulation also identifies the emitted dislocation as a source for microcrack nucleation. A simple method is used to examine this nucleation process. © 1996 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.363383

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

2

Digitale Medien

Simulation of nucleation and emission of dislocations by molecular-dynamics method (1995)

Zhang, Y. W. ; Wang, T. C. ; Tang, Q. H.

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 77 (1995), S. 2393-2399

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: The nucleation and emission of dislocations from the crack tip under mode II loading are analyzed by the molecular-dynamics method in which the Finnis–Sinclair potential has been used. A suitable atom lattice configuration is employed to allow one to fully analyze the nucleation, emission, dissociation, and pileup of the dislocations. The calculated results show that although the pure mode II loading is applied, the crack tip generally exhibits a combined mode. The stress distributions before the dislocation emission are in agreement with the elasticity solution, but are not after the emission. The critical stress intensity factor corresponding to the dislocation nucleation KIIe is dependent on the loading rate K(overdot)II. The separations of a pair of partial dislocations and the full dislocations are also dependent on the loading rate. When the first partial dislocation is blocked, a pileup of dislocations can be set up. It is also found that the dislocation can move at subsonic wave speed (less than the shear wave speed) or at transonic speed (greater than the shear wave speed but less than the longitudinal wave speed) depending on the loading rate, but at the longitudinal wave speed which just corresponds to K(overdot)II=1.15 MPa (square root of)m/ps for copper, the atom lattice breaks down. © 1995 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.358764

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

3

Digitale Medien

Dislocation dynamics of strain relaxation in epitaxial layers (2001)

Wang, T. C.

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 89 (2001), S. 6069-6072

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: Many experimental observations have clearly shown that dislocation interaction plays a crucial role in the kinetics of strain relaxation in epitaxial thin films. A set of evolution equations are presented in this article. The key feature of the equations is the incorporation of dislocation interactions into the kinetic process by introducing a resistance term. The resistance to threading dislocation gliding is characterized by a hardening function, which depends only on the relaxed plastic strain. The evolution equations are tested on the GexSi1−x/Si(100) materials system. Existing fundamental parameters are incorporated into the present model. The evolution equations successfully reproduce a wide range of experimental data on strain relaxation in GexSi1−x/Si heterostructures. © 2001 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1369396

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

4

Digitale Medien

Parametric investigation of the dirt spike generation in a pulsed metal vapor laser discharge (1989)

Lin, C. E. ; Yang, C. Y. ; Wang, T. C. ; [weitere]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 65 (1989), S. 4542-4547

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: The generation of dirt spikes in the discharge of a clean pulsed metal vapor laser is measured under various operating conditions, such as a change in pulse repetition rates, laser tube temperatures, buffer gas pressures, and charging voltages. It is shown that the dirt spikes will increase in magnitude for such conditions that the pulse repetition rate decreases, the laser tube temperature decreases, and the buffer gas pressure increases. The ratio of the dirt spike to the charging voltage will also increase as the charging voltage decreases. All experimental results are well explained by theoretical analyses. These results lead to a number of useful suggestions for the operation of a pulsed metal vapor laser.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.343251

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

5

Digitale Medien

A 25-W longitudinal, discharge-heated copper vapor laser (1989)

Wang, T. C. ; Yang, C. Y. ; Lee, W. S. ; [weitere]

[S.l.] : American Institute of Physics (AIP)

Review of Scientific Instruments 60 (1989), S. 3351-3352

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7623

Quelle: AIP Digital Archive

Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik

Notizen: A longitudinal, discharge-heated copper vapor laser with an internal diameter of 4.2 cm and a length of 150 cm has been constructed. At the charging voltage of 14.5 kV, buffer gas pressure of 20 Torr, pulse repetition rate of 6.5 kHz, and laser tube temperature of 1450 °C; the laser offers an average power of 25 W with excellent stability and requires a minimum amount of maintenance.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1140531

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

6

Digitale Medien

Impedance monitor to protect the thyratron in metal vapor lasers (1989)

Lin, C. E. ; Yang, C. Y. ; Wang, T. C. ; [weitere]

[S.l.] : American Institute of Physics (AIP)

Review of Scientific Instruments 60 (1989), S. 2893-2895

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7623

Quelle: AIP Digital Archive

Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik

Notizen: It is found that the appearance of high reverse-voltage spikes on the thyratron anode in the discharge of metal vapor lasers due to high laser impedances can easily be monitored by a dc current meter in series with the bypass inductor of the discharge circuit. Experiments are demonstrated using a copper vapor laser. Results show that the proposed impedance monitor is effective, reliable, and economical. The meter deflection corresponding to acceptable, well-behaved thyratron operation can be obtained easily by the residual ionization-control method using a clean laser tube. By keeping the deflection within a specified limit, the lifetime of thyratron can greatly be extended.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1140624

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

7

Digitale Medien

First experimental demonstration of NMR dynamic frequency shifts: dispersion versus absorption (DISPA) line shape analysis of sodium-23 in aqueous sodium laurate/lauric acid solution (1982)

Marshall, Alan G. ; Wang, T. C. L. ; Cottrell, Charles E. ; [weitere]

s.l. : American Chemical Society

Journal of the American Chemical Society 104 (1982), S. 7665-7666

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1520-5126

Quelle: ACS Legacy Archives

Thema: Chemie und Pharmazie

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1021/ja00390a050

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

8

Digitale Medien

Growth of AlxGa1−xN:Ge on sapphire and silicon substrates (1995)

Zhang, X. ; Kung, P. ; Saxler, A. ; [weitere]

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 67 (1995), S. 1745-1747

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1077-3118

Quelle: AIP Digital Archive

Thema: Physik

Notizen: AlxGa1−xN were grown on (00.1) sapphire and (111) silicon substrates in the whole composition range (0≤x≤1). The high optical quality of the epilayers was assessed by room-temperature optical absorption and photoluminescence measurements. Layers with higher Al composition are more resistive. Resistive AlxGa1−xN epilayers were successfully doped with Ge and free-electron concentration as high as 3×1019 cm−3 was achieved. © 1995 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.115036

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

9

Digitale Medien

High quality AIN and GaN epilayers grown on (00⋅1) sapphire, (100), and (111) silicon substrates (1995)

Kung, P. ; Saxler, A. ; Zhang, X. ; [weitere]

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 66 (1995), S. 2958-2960

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1077-3118

Quelle: AIP Digital Archive

Thema: Physik

Notizen: The growth of high quality AlN and GaN thin films on basal plane sapphire, (100), and (111) silicon substrates is reported using low pressure metalorganic chemical vapor deposition. X-ray rocking curve linewidths of about 100 and 30 arcsec were obtained for AlN and GaN on sapphire, respectively. Room-temperature optical transmission and photoluminescence (of GaN) measurements confirmed the high quality of the films. The luminescence at 300 and 77 K of the GaN films grown on basal plane sapphire, (100), and (111) silicon was compared. © 1995 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.114242

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

10

Digitale Medien

Coulomb broadening in Fourier transform ion cyclotron resonance mass spectrometry

Lin Wang, T.-C. ; Marshall, A.G.

Amsterdam : Elsevier

International Journal of Mass Spectrometry and Ion Processes 68 (1986), S. 287-301

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0168-1176

Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Thema: Chemie und Pharmazie , Physik

Materialart: Digitale Medien

URL: http://linkinghub.elsevier.com/retrieve/pii/0168-1176(86)87053-7

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext