TY  - JOUR
A1  - Ermeydan, Mahmut Ali
A1  - Cabane, Etienne
A1  - Masic, Admir
A1  - Koetz, Joachim
A1  - Burgert, Ingo
T1  - Flavonoid insertion into cell walls improves wood properties
JF  - ACS applied materials & interfaces
N2  - Wood has an excellent mechanical performance, but wider utilization of this renewable resource as an engineering material is limited by unfavorable properties such as low dimensional stability upon moisture changes and a low durability. However, some wood species are known to produce a wood of higher quality by inserting mainly phenolic substances in the already formed cell walls a process so-called heartwood formation. In the present study, we used the heartwood formation in black locust (Robinia pseudoacacia) as a source of bioinspiration and transferred principles of the modification in order to improve spruce wood properties (Picea abies) by a chemical treatment with commercially available flavonoids. We were able to effectively insert hydrophobic flavonoids in the cell wall after a tosylation treatment for activation. The chemical treatment reduced the water uptake of the wood cell walls and increased the dimensional stability of the bulk spruce wood. Further analysis of the chemical interaction of the flavonoid with the structural cell wall components revealed the basic principle of this bioinspired modification. Contrary to established modification treatments, which mainly address the hydroxyl groups of the carbohydrates with hydrophilic substances, the hydrophobic flavonoids are effective by a physical bulking in the cell wall most probably stabilized by pi-pi interactions. A biomimetic transfer of the underlying principle may lead to alternative cell wall modification procedures and improve the performance of wood as an engineering material.
KW  - wood cell wall
KW  - heartwood formation
KW  - chemical modification
KW  - Raman spectroscopy
KW  - dimensional stability
KW  - nanoindentation
Y1  - 2012
U6  - https://doi.org/10.1021/am301266k
SN  - 1944-8244
VL  - 4
IS  - 11
SP  - 5782
EP  - 5789
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Sumpf, Bernd
A1  - Maiwald, Martin
A1  - Muller, Andre
A1  - Ginolas, Arnim
A1  - Haeusler, Karl
A1  - Erbert, Goetz
A1  - Traenkle, Guenther
T1  - Reliable operation for 14 500 h of a wavelength-stabilized Diode Laser System on a Microoptical Bench at 671 nm
JF  - IEEE transactions on components, packaging and manufacturing technology
N2  - Reliability tests for wavelength-stabilized compact diode laser systems emitting at 671 nm are presented. The devices were mounted on microoptical benches with the dimensions of 13 mm x 4 mm. Reflecting Bragg gratings were used for wavelength stabilization and emission width narrowing. The reliability tests were performed at 25 degrees C and at an output power up to 10 mW per micrometer stripe width of the gain medium. Reliable operation could be demonstrated over a test time up to 14 500 h at an output power up to 1.0 W. Environmental tests using random vibrations with acceleration up to 29 g were performed without deterioration of the devices.
KW  - High-power lasers
KW  - laser resonators
KW  - Raman spectroscopy
KW  - reliability
KW  - semiconductor lasers
Y1  - 2012
U6  - https://doi.org/10.1109/TCPMT.2011.2171342
SN  - 2156-3950
VL  - 2
IS  - 1
SP  - 116
EP  - 121
PB  - Inst. of Electr. and Electronics Engineers
CY  - Piscataway
ER  -