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- 2002 (697) (entfernen)
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- Englisch (697) (entfernen)
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- Concrete (6)
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- Non-destructive testing (5)
- Radar (5)
- Oligomers (4)
- Cone calorimeter (3)
- Impact-Echo (3)
- MALDI (3)
- Microphone (3)
- Rhenium (3)
Eingeladener Vortrag
- nein (250)
The 125-fs laser ablation behaviour (800 nm) of aluminium and anodic oxide coatings on an AlMgSi1 alloy was investigated. The multi-pulse ablation threshold of aluminium at 1.2 J cm-2 was less than that of the oxides of 23 J cm-2. Aluminium exhibited a single pulse modification (melting) threshold of 0.3 J cm-2. These values derived from an evaluation of the crater geometry coincided with on-line acoustic measurements. The detected microphone voltage amplitude increased linearly with the laser fluence. The morphology of the ablation craters on aluminium indicated melt formation and displacement of a homogeneous melt phase due to the recoil action of the expanding metal vapour. The laser-processed ceramic oxide phases, on the other hand, showed a spongy resolidified melt layer, which denotes a collocated in-depth formation both of a melt and a gas phase. These phenomena are discussed in terms of the relative dominance of penetration depth of laser light and heat affected zones in the investigated materials with strongly varying optical and thermodynamical properties.
The ultrafast laser ablation of silicon has been investigated experimentally and theoretically. The theoretical description is based on molecular dynamics (MD) simulations combined with a microscopic electronic model. We determine the thresholds of melting and ablation for two different pulse durations =20 and 500 fs. Experiments have been performed using 100 Ti:Sap-phire laser pulses per spot in air environment. The ablation thresholds were determined for pulses with a duration of 25 and 400 fs, respectively. Good agreement is obtained between theory and experiment.
Promoting the infrastructure - prestandardisation endeavours for ceramic powders and green bodies
(2002)
Tribology of Advanced Ceramics III: Principles of solid lubrication - materials and mechanisms
(2002)
GDS-Forum Website
(2002)
The fuctional expression of human bone derived cells grown on resorbable bioactive glass ceramics
(2002)
Thin Film Reference Materials for Thickness Measurement by XRF and GIXR in the Nanometre Range
(2002)
Data processing at BAM
(2002)
Modeling the reinforcement of alloys by hard precipitates: The example of Nibase of superalloy
(2002)
The focused ion beam technique - eine interessante Alternative, auch für konventionelle Werkstoffe
(2002)
Standard reference materials
(2002)
On drafting a new European standard "Gas Explosion Venting Protective Systems" a lack of data has been identified for venting at low activation pressures. Therefore, experiments have been performed on vented gas explosions using bursting foils of different strength. Cylinders of different volumes and length-to-diameter ratios (L/D) have been used as explosion vessels. The vessels were made from glass to make the flame propagation observable by a high-speed video system. For the dependence of the reduced explosion pressure Pred on L/D a maximum occurred for L/D about 3. This could be shown for vessels of different volumes and for different vent sizes. Using bursting foils of different strength it could be shown that the pressure evolution after the vent had opened, depended on the activation pressure only, when the vent size was to small to prevent a second peak in the pressure- time curve.