Materials Literature
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Nanostructured carbonaceous materials, that is, carbon materials with a feature size on the nanometer scale and, in some cases, functionalized surfaces, already play an important role in a wide range of emerging fields, such as the search for novel energy sources, efficient energy storage, sustainable chemical technol…
Dendrimer synthesis should not be tedious and time-consuming. By utilizing an AB 2 −CD 2 approach and having orthogonal, “clickable” groups on each monomer, the time for dendrimer assembly can be drastically reduced. This was shown by preparation of a sixth generation dendrimer from starting monomer units in a single…
A tight-binding analytic framework is combined with first-principles calculations to reveal the mechanism underlying the strain effects on electronic structures of graphene and graphene nanoribbons (GNRs). It provides a unified and precise formulation of the strain effects under various circumstances-including the shi…
Microscopic, structural, transport, and thermodynamic measurements of single crystalline $\text{Ba}{({\text{Fe}}_{1\ensuremath{-}x}{\text{TM}}_{x})}_{2}{\text{As}}_{2}$ ($\text{TM}=\text{Ni}$ and Cu) series, as well as two mixed $\text{TM}=\text{Cu}/\text{Co}$ series, are reported. In addition, high-magnetic field, an…
We propose a simple, yet highly efficient and robust device for producing valley polarized current in graphene. The device comprises of two distinct components; a region of uniform uniaxial strain, adjacent to an out-of-plane magnetic barrier configuration formed by patterned ferromagnetic stripes. We show that when t…
Putting the pedal to the metal: A facile strategy for the synthesis of metal nanocrystals is demonstrated that employs carbon monoxide as a reducing agent. Highly monodisperse platinum nanocubes, spherical palladium nanocrystals, and ultrathin gold nanowires can be produced within 15 minutes.
Small fluorescent atomic copper clusters, stabilized by tetrabutylammonium nitrate, have been synthesized by a simple electrochemical technique. These small clusters (Cu N, N < ≈14) show photoluminescence in the visible range with unusual high quantum yields (13%) and were characterized by UV−vis and fluorescence spec…
We have investigated the reaction mechanism responsible for QD nucleation using optical absorption and nuclear magnetic resonance spectroscopies. For typical II-VI and IV-VI quantum dot (QD) syntheses, pure tertiary phosphine selenide sources (e.g., trioctylphosphine selenide (TOPSe)) were surprisingly found to be unr…
A simple analytic analysis of the ultra-high reflectivity feature of subwavelength dielectric gratings is developed. The phenomenon of ultra high reflectivity is explained to be a destructive interference effect between the two grating modes. Based on this phenomenon, a design algorithm for broadband grating mirrors i…
Multiple exciton generation (MEG) in quantum dots (QDs) and impact ionization (II) in bulk semiconductors are processes that describe producing more than one electron-hole pair per absorbed photon. We derive expressions for the proper way to compare MEG in QDs with II in bulk semiconductors and argue that there are im…
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The mechanochromic and thermochromic luminescence properties of a molecular copper(I) iodide cluster formulated [Cu(4)I(4)(PPh(2)(CH(2)CH=CH(2)))(4)] are reported. Upon mechanical grinding in a mortar, its solid-state emission properties are drastically modified as well as its thermochromic behavior. This reversible p…
Spider dragline silk is a remarkably strong fiber that makes it attractive for numerous applications. Much has thus been done to make similar fibers by biomimic spinning of recombinant dragline silk proteins. However, success is limited in part due to the inability to successfully express native-sized recombinant silk…
In the work described in this paper, we have successfully fabricated flexible asymmetric supercapacitors (ASCs) based on transition-metal-oxide nanowire/single-walled carbon nanotube (SWNT) hybrid thin-film electrodes. These hybrid nanostructured films, with advantages of mechanical flexibility, uniform layered struct…
The field of thermoelectrics has progressed enormously and is now growing steadily because of recently demonstrated advances and strong global demand for cost-effective, pollution-free forms of energy conversion. Rapid growth and exciting innovative breakthroughs in the field over the last 10-15 years have occurred in…
Helium leak tests were completed to characterize the leak rate of a 54 in. diameter composite space docking seal design in support of the National Aeronautics and Space Administration s (NASA's) Low Impact Docking System (LIDS). The evaluated seal design was a candidate for the main interface seal on the LIDS, which w…
A novel docking seal was developed for the main interface seal of NASA s Low Impact Docking System (LIDS). This interface seal was designed to maintain acceptable leak rates while being exposed to the harsh environmental conditions of outer space. In this experimental evaluation, a candidate docking seal assembly call…
The General-Purpose Heat Source Radioisotope Thermoelectric Generator (GPHS-RTG) has been the workhorse nuclear power source of the space science community for over 20 years having powered such challenging missions as Galileo, Ulysses, Cassini and New Horizons. At ≥300 We beginning of life (BOL) power, the GPHS-RTG is…
In this paper, synthesis and characterization of cerium dioxide (CeO 2 ) or ceria nanoparticles are presented. Nanoparticles of cerium dioxide were synthesized by solution method using a microwave oven. The precursor used to prepare the nanoparticles of CeO 2 was ammonium ceric nitrate. The precursor was dissolved in…
The purpose of the present work was to determine the identity of the enzymes that synthesize N-acetylaspartylglutamate (NAAG), the most abundant dipeptide present in vertebrate central nervous system (CNS), and β-citrylglutamate, a structural analogue of NAAG present in testis and immature brain. Previous evidence sug…