In this study, the ballistic performance of armors composed of a polyurea elastomer/Kevlar fabric composite and a shear thickening fluid (STF) structure was investigated. The polyurea used was a reaction product of aromatic diphenylmethane isocyanate (A agent) and amine-terminated polyether resin (B agent). The A and B agents were diluted, mixed and brushed onto Kevlar fabric. After the reaction of A and B agents was complete, the polyurea/Kevlar composite was formed. STF structure was prepared through pouring the STF into a honeycomb paper panel. The ballistic tests were conducted with reference to NIJ 0101.06 Ballistic Test Specification Class II and Class IIIA, using 9 mm FMJ and 44 magnum bullets. The ballistic test results reveal that polyurea/Kevlar fabric composites offer better impact resistance than conventional Kevlar fabrics and a 2 mm STF structure could replace approximately 10 layers of Kevlar in a ballistic resistant layer. Our results also showed that a high-strength composite laminate using the best polyurea/Kevlar plates combined with the STF structure was more than 17% lighter and thinner than the conventional Kevlar laminate, indicating that the high-strength protective material developed in this study is superior to the traditional protective materials.

The mechanisms responsible for the transparency of Ni/Au and Ni/Au/ZnO on p-GaN has been investigated. It was found that the optical transmission of Ni/Au contacts is dominated by the film thickness and morphology. A change in film thickness, induced by thermal annealing, results in a more transparent contact material. In addition a ZnO film was used as an antireflection layer on top of a Ni/Au contact. The Ni/Au/ZnO film was found to have an increased light transmission of 15% compared with an annealed Ni/Au contact. The maximum optical transmission measured through the Ni/Au/ZnO contact was 90%.

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Multiwalled carbon nanotubes (MWCNTs) with uniform diameters (10−20 nm) and high densities per unit area were synthesized in a 5−10 s combustion process using a mixture of butane and air at 880 °C. The growth mechanism of MWCNTs was studied via time-sequence experiments to reveal that the catalyst nanoparticles were formed on a 3 nm thick Ni-coated wafer after 3 s in the flame. Short and uniform MWCNTs were synthesized using a 5 s process, whereas MWCNTs with a maximum density and length were obtained using a 10 s process. It is believed that both the synthesis temperature and the combustion products, such as CO, H2O, C n H m (n = 1 or 2), and polycyclic aromatic hydrocarbons, play an important role in the growth of the MWCNTs. Furthermore, the field emission properties of the combustion-generated carbon nanotube (CNT) films were studied, and an emission current density of 0.18 mA/cm2 at 7 V/μm was obtained. These results suggested that this fabrication method provided rapid and direct growth of field-emission CNTs on a desired substrate.

A field-emission light source with high luminance, excellent luminance uniformity, and tunable luminance characteristics with a novel lateral-gate structure is demonstrated. The lateral-gate triode structure comprises SiC nanowire emitters on a Ag cathode electrode and a pair of Ag gate electrodes placed laterally on both sides of the cathode. The simple and cost-effective screen printing technique is employed to pattern the lateral-gates and cathode structure on soda lime glass. The area coverage of the screen-printed cathode and gates on the glass substrate (area: 6 × 8 cm2) is in the range of 2.04% – 4.74% depending on the set of cathode-gate electrodes on the substrate. The lateral-gate structure with its small area coverage exhibits a two-dimensional luminance pattern with high brightness and good luminance uniformity. A maximum luminance of 10952 cd/cm2 and a luminance uniformity of >90% can be achieved with a gate voltage of 500 V and an anode voltage of 4000 V, with an anode current of 1.44 mA and current leakage to the gate from the cathode of about 10%.

Corrosion prevention and infrared (IR) stealth are conflicting goals. While graphene nanosheets (GN) provide an excellent physical barrier against corrosive agent diffusion, thus lowering the permeability of anti-corrosion coatings, they have the side-effect of decreasing IR stealth. In this work, the anti-corrosion properties of 100-μm-thick composite epoxy coatings with various concentrations (0.01–1 wt.%) of GN fillers thermally reduced at different temperatures (300 °C, 700 °C, 1100 °C) are first compared. The performance was characterized by potentiodynamic polarization scanning, electrochemical impedance spectroscopy, water contact angle and salt spray tests. The corrosion resistance for coatings was found to be optimum at a very low filler concentration (0.05 wt.%). The corrosion current density was 4.57 × 10−11 A/cm2 for GN reduced at 1100 °C, showing no degradation after 500 h of salt-spray testing: a significant improvement over the anti-corrosion behavior of epoxy coatings. Further, to suppress the high IR thermal signature of GN and epoxy, Al was added to the optimized composite at different concentrations. The increased IR emissivity due to GN was not only eliminated but was in fact reduced relative to the pure epoxy. These optimized coatings of Al-GN-epoxy not only exhibited greatly reduced IR emissivity but also showed no sign of corrosion after 500 h of salt spray test.

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