ISSN:1042-0150    

DOI:10.1080/10420159408228871

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This abstract consists of reformatted slides from the talk with a small amount of added connective tissue. First we outline important research areas in High Performance Computing and Communication (HPCC) with an overview of current LLNL work in each area, and then we discuss in more detail some of LLNL's evolving views on massively parallel computing.

ISSN:1042-0150    

DOI:10.1080/10420159408228872

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159408228873

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159408228874

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The evolution of irradiation damage cascades in copper has been simulated by molecular dynamics, using a many-body potential. Nearly 200 cascades have been produced with random knock-on directions and primary knock-on atom (PKA) energies in the range from 60 eV to 10 keV. The starting temperature for these simulations was 100 K and 600 K, this report will confine itself to the data obtained at 100 K. The cascade evolution has been followed for times typically up to ∼10 psec and in some cases up to ∼30 psec. The cascades are characterised by the sudden emission of replacement collision sequences and with shape variations due to local channelling events. At the higher energies the core has been shown to be liquid-like structure with cavitation. The annealing phase leaves loosely clustered vacancies at the cascade centre but collapse to a vacancy loop is not generally observed. A feature of the more energetic cascades is the production by a ballistic mechanism of interstitial atom clusters at the periphery of the cascades.

ISSN:1042-0150    

DOI:10.1080/10420159408228875

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We have performed molecular dynamics computer simulation studies of 25 keV displacement cascades in Cu at low temperature. At this energy we observe the initial splitting of a cascade into subcascades and show that at low temperatures in metals displacement cascades can lead to the formation of both vacancy and interstitial dislocations loops. We discuss a new mechanism of defect production based on the observation of interstitial prismatic dislocation loop punching from cascades at 10 K. We also show that below the subcascade threshold, atomic mixing in the cascade is recoil-energy dependent. We obtain a mixing efficiency that is proportional to the square root of the recoil energy.

ISSN:1042-0150    

DOI:10.1080/10420159408228876

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159408228877

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

An interatomic potential is described, the rotated second moment approximation (RSMA), which incorporates directional bonding through energy moments evaluated over directional atomic orbitals. When non-directional orbitals are used, RSMA reduces to the standard SMA, and is thus capable of describing metallic systems. A model RSMA potential is demonstrated for 3d transition metals, with only first neighbor shell interactions, which can correctly predict the experimental trend in the relative stability of the fee and hep structures. A generalization of RSMA is proposed thai is related in the same way thai the embedded atom method (EAM) is related to the SMA. A generalized fee RSMA potential is constructed for which the Cauchy pressure can be made negative by systemaiically adjusting one parameier. This behavior results from the angular (directional) forces and not from a physically-unreasonable embedding function.

ISSN:1042-0150    

DOI:10.1080/10420159408228878

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Presented at the IEA Workshop on the Use of Molecular Dynamics in Modelling Radiation Effects and Other Non-equilibrium Phenomena, May 6–8, 1991 at La Jolla, USA

ISSN:1042-0150    

DOI:10.1080/10420159408228879

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159408228880

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor