Optimization of hole generation in Ti/CFRP stacks

Carbon fiber-reinforced plastics (CFRP), which are now used in some aerospace applications, is difficult to cut and drill holes in. Moreover, no reports have focused on selecting a suitable drilling method for each aerospace part. This paper discusses many methods of hole generation for CFRP composites, including methods using traditional drill tools and non-traditional methods such as abrasive water jet (AWJ), laser beam and abrasive blast. We look at traditional cemented carbide material tools, polycrystalline diamond (PCD) tools, diamond-like carbon (DLC) coated tools and ceramic tools. Then, comparing the experimental results of these methods from the viewpoints of characteristics, efficiency, cost, and hole quality, we investigate each problem to select the suitable drilling method. As a result, we propose a novel method to strategically obtain the best solutions to generate holes in aerospace parts.

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Study on the Correlation between the Noise by Hole Generation and Surface Recombination Velocity at Ge Fused Junction

Journal of the Physical Society of Japan ◽

10.1143/jpsj.13.1409 ◽

1958 ◽

Vol 13 (11) ◽

pp. 1409-1410

Author(s):

Kiichi Komatsubara

Keyword(s):

Surface Recombination ◽

Surface Recombination Velocity ◽

Recombination Velocity ◽

Hole Generation

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Uncovering dark multichromophoric states in Peridinin–Chlorophyll–Protein

Journal of The Royal Society Interface ◽

10.1098/rsif.2019.0736 ◽

2020 ◽

Vol 17 (164) ◽

pp. 20190736

Author(s):

Elliot J. Taffet ◽

Francesca Fassioli ◽

Zi S. D. Toa ◽

David Beljonne ◽

Gregory D. Scholes

Keyword(s):

Crystal Structure ◽

Excited States ◽

Quantum Chemical ◽

Light Harvesting ◽

Singlet Fission ◽

Chlorophyll Protein ◽

Triplet Pair ◽

A Charge ◽

Hole Generation ◽

Chemical Evidence

It has long been recognized that visible light harvesting in Peridinin–Chlorophyll–Protein is driven by the interplay between the bright (S 2 ) and dark (S 1 ) states of peridinin (carotenoid), along with the lowest-lying bright (Q y ) and dark (Q x ) states of chlorophyll- a . Here, we analyse a chromophore cluster in the crystal structure of Peridinin–Chlorophyll–Protein, in particular, a peridinin–peridinin and a peridinin–chlorophyll- a dimer, and present quantum chemical evidence for excited states that exist beyond the confines of single peridinin and chlorophyll chromophores. These dark multichromophoric states, emanating from the intermolecular packing native to Peridinin–Chlorophyll–Protein, include a correlated triplet pair comprising neighbouring peridinin excitations and a charge-transfer interaction between peridinin and the adjacent chlorophyll- a . We surmise that such dark multichromophoric states may explain two spectral mysteries in light-harvesting pigments: the sub-200-fs singlet fission observed in carotenoid aggregates, and the sub-200-fs chlorophyll- a hole generation in Peridinin–Chlorophyll–Protein.

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