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Thermal Conductivity Performance Of Polypropylene Composites Filled With Polydopamine-Functionalized Hexagonal Boron Nitride, Lin Chen, Hong-Fei Xu, Shao-Jian He, Yi-Hang Du, Nan-Jie Yu, Jun Lin, Sergei I. Nazarenko Jan 2017

Thermal Conductivity Performance Of Polypropylene Composites Filled With Polydopamine-Functionalized Hexagonal Boron Nitride, Lin Chen, Hong-Fei Xu, Shao-Jian He, Yi-Hang Du, Nan-Jie Yu, Jun Lin, Sergei I. Nazarenko

Faculty Publications

Mussel-inspired approach was attempted to non-covalently functionalize the surfaces of boron nitride (BN) with self-polymerized dopamine coatings in order to reduce the interfacial thermal barrier and enhance the thermal conductivity of BN-containing composites. Compared to the polypropylene (PP) composites filled with pristine BN at the same filler content, thermal conductivity was much higher for those filled with both functionalized BN (f-BN) and maleic anhydride grafted PP (PP-g-ma) due to the improved filler dispersion and better interfacial filler-matrix compatibility, which facilitated the development of more thermal paths. Theoretical models were also applied to predict the composite thermal conductivity in which the …


Measurement Of Semiconductor Surface Potential Using The Scanning Electron Microscope, Jennifer T. Heath, Chun-Sheng Jiang, Mowafak M. Al-Jassim Jan 2012

Measurement Of Semiconductor Surface Potential Using The Scanning Electron Microscope, Jennifer T. Heath, Chun-Sheng Jiang, Mowafak M. Al-Jassim

Faculty Publications

We calibrate the secondary electron signal from a standard scanning electron microscope to voltage, yielding an image of the surface or near-surface potential. Data on both atomically abrupt heterojunction GaInP/GaAs and diffused homojunction Si solar cell devices clearly show the expected variation in potential with position and applied bias, giving depletion widths and locating metallurgical junctions to an accuracy better than 10 nm. In some images, distortion near the p-n junction is observed, seemingly consistent with the effects of lateral electric fields (patch fields). Reducing the tube bias removes this distortion. This approach results in rapid and straightforward collection of …


Ultrastructure Of Teliospores And Promycelium And Basidiospore Formation In The Four-Spored Form Of Gymnoconia Nitens, One Of The Causes Of Orange Rust Of Rubus, C. W. Mims, E. A. Richardson, Josephine Taylor Jan 2007

Ultrastructure Of Teliospores And Promycelium And Basidiospore Formation In The Four-Spored Form Of Gymnoconia Nitens, One Of The Causes Of Orange Rust Of Rubus, C. W. Mims, E. A. Richardson, Josephine Taylor

Faculty Publications

Orange rust of Rubus is an interesting disease because of the fact that it can be caused by three different rust fungi that produce virtually identical symptoms. One is Gymnoconia peckiana (Howe in Peck) Trotter, which is a demicyclic species, while the other two are endocyclic forms historically referred to as Gymnoconia nitens (Schwein.) Kern & H.W. Thurston. Although the spores produced on infected Rubus leaves by these latter two forms are morphologically identical to the aeciospores of G. peckiana, they actually function as teliospores. However, the teliospores of one of the forms gives rise to two-celled promycelia that …


Development Of Method For Synthesis Of Pt–Co Cathode Catalysts For Pem Fuel Cells, Xuguang Li, Héctor R. Colón-Mercado, Gang Wu, Jong-Won Lee, Branko N. Popov Jan 2007

Development Of Method For Synthesis Of Pt–Co Cathode Catalysts For Pem Fuel Cells, Xuguang Li, Héctor R. Colón-Mercado, Gang Wu, Jong-Won Lee, Branko N. Popov

Faculty Publications

A procedure was developed to synthesize a platinum–cobalt (Pt–Co) alloy electrocatalyst for oxygen reduction using Co/C composite as a support. The Pt–Co/C catalysts were synthesized through: (i) chemical oxidation of carbon black, (ii) Co deposition on the oxidized carbon using a chelation method, (iii) chemical treatment in an acidic medium to remove excess of Co on the carbon surface, (iv) Pt deposition onto the Co/C support, and (v) postheat treatment to form the Pt–Co alloy catalyst. The synthesized Pt–Co/C catalyst showed improved activity and long-term stability in polymer electrolyte membrane …


Corrosion Protection Of Steel Using Nonanomalous Ni-Zn-P Coatings, Basker Veeraraghavan, Bala Haran, Swaminatha P. Kumaraguru, Branko N. Popov Jan 2003

Corrosion Protection Of Steel Using Nonanomalous Ni-Zn-P Coatings, Basker Veeraraghavan, Bala Haran, Swaminatha P. Kumaraguru, Branko N. Popov

Faculty Publications

A novel technique for obtaining nonanomalous Ni-Zn-P coatings with high Ni content (74 wt % as compared to 15-20 wt % in the conventional plating method) has been developed. These coatings show promise as a replacement for Cd in sacrificially protecting steel. Ni-Zn-P coatings were deposited using an electroless method from a solution containing NiSO4, complexing agent and ammonium chloride. Varying the concentration of ZnSO4 in the bath controls the final amount of Zn in the deposit. The Zn content in the coating was optimized based on the corrosion resistance of the final deposit. Coatings with 16.2 …


Thermally Stable Gel Polymer Electrolytes, Min-Kyu Song, Young-Taek Kim, Yong Tae Kim, Byung Won Cho, Branko N. Popov, Hee-Woo Rhee Jan 2003

Thermally Stable Gel Polymer Electrolytes, Min-Kyu Song, Young-Taek Kim, Yong Tae Kim, Byung Won Cho, Branko N. Popov, Hee-Woo Rhee

Faculty Publications

To prepare miscible polyethylene glycol diacrylate/polyvinylidene fluoride (PEGDA/PVdF) blend gel polymer electrolytes, low molecular weight (M = 742) liquid PEGDA oligomer was mixed with PVdF-HFP dissolved in ethylene carbonate/dimethyl carbonate/LiPF6 liquid electrolytes, and then cured under ultraviolet irradiation. Room temperature conductivity of PEGDA/PVdF blend films was found to be comparable to that of PVdF-HFP gel polymer electrolytes, and they were electrochemically stable up to 4.6 V vs. Li/Li+. Scanning electron micrographs revealed that PEGDA/PVdF blend electrolytes have pore size intermediate between dense PEGDA and highly porous PVdF-HFP. It was confirmed by weight change measurement that liquid electrolyte …