Study on carbon fiber surface treatment based on surface oxidation method
Surface conditions of carbon fibers severely effect on the bonding strength between the fibers and the matrix, even on the mechanical properties of the composites when carbon fibers were used as reinforcement on the preparation of ceramic matrix composites. Surface treatment of carbon fibers was carried out based on the air oxidation method and the liquid oxidation method with concentrated nitric acid (68%) as the oxidizing solution. It could remove impurities from the surface of carbon fibers and increase the degree of the surface concavoconvex, so the active surface area were increased and then improved the bonding strength between fibers and matrix. The surface topographies of carbon fibers after surface oxidation were characterized by SEM. The results illustrate that, impurities on the surface of carbon fibers are decreased and there are many longitudinal grooves evenly distributed on the surface in favor of increasing the bonding strength between the fibers and matrix.
Surface Treatment of Carbon Fiber for Composites
The carbon fiber and its composites have many excellent performances,such as the high specific strength,the high specific modulus,the heat endurance,anti-corrosion,anti-fatigue,anti-creep etc.It is very important to treat the surface of carbon fibre for making use of its performances.This thesis summarizes several approaches of surface treatment of carbon fibre,for example,gas oxidation,electrolysis oxidation,liquid oxidation, plasma oxidation,electro-polymerization,vapor deposition,electroplating,and compares the influences of different surface treatment methods on the fiber's structure and properties.The surface treatment of carbon fiber is an important measure that makes use of its performances.The surface treatment of carbon fiber is different for making use of requirement.By comparing several treatment approaches,it can be concluded that: ozone oxidation,anode electrolysis oxidation and plasma oxidation are widely used now.
Coronoid reconstruction using osteochondral grafts: a biomechanical study.
HYPOTHESIS
The purposes of this study were to test the hypothesis that coronoid deficiency in the setting of posteromedial rotatory instability (PMRI) must be reconstructed to restore articular contact pressures to normal and to compare 3 different osteochondral grafts for this purpose.


METHODS
After creation of a anteromedial fracture, six cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and to passively flex the elbow. Mean articular surface contact pressure data were collected and processed using TekScan sensors and software. After testing of the intact specimen (intact condition), a PMRI injury was created (PMRI condition). Testing was repeated after reconstruction of the lateral collateral ligament (LCL) (LCL-only condition), followed by reconstruction of the coronoid with 3 different osteochondral graft techniques (reconstructed conditions).


RESULTS
Contact pressure was consistently significantly higher in the PMRI elbow compared with the intact, LCL-only, and reconstructed conditions (P < .006). The LCL-only elbow contact pressure was significantly higher than that of the intact and reconstructed conditions from 5° to 55° of flexion (P = .018). The contact pressure of the intact elbow was never significantly different from that of the reconstructed elbow, except at 5° of flexion (P ≤ .008). No significant difference was detected between each of the reconstructed techniques (P ≥ .15). However, the annular surface of the radial head was the only graft that yielded contact pressures not significantly different from normal at any flexion angle.


CONCLUSION
Isolated reconstruction of the LCL did not restore native articular surface contact pressure, and reconstruction of the coronoid using osteochondral graft was necessary. There was no difference in contact pressures among the 3 coronoid reconstruction techniques.