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Li, Teng

Publications and source records attributed to Li, Teng.

27 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Transparent, Anisotropic Biofilm with Aligned Bacterial Cellulose Nanofibers

Abstract Cellulose nanofibrils are attractive as building blocks for advanced photonic, optoelectronic, microfluidic, and bio‐based devices ranging from transistors and solar cells to fluidic and biocompatible injectable devices. For the first time, an ultrastrong and ultratough cellulose film, which is composed of densely packed bacterial cellulose (BC) nanofibrils with hierarchical fibril alignments, is successfully demonstrated. The molecular level alignment stems from the intrinsic parallel orientation of crystalline cellulose molecules produced by Acetobacter xylinum. These aligned long‐chain cellulose molecules form subfibrils with a diameter of 2–4 nm, which are further aligned to form nanofibril bundles. The BC film yields a record‐high tensile strength (≈1.0 GPa) and toughness (≈25 MJ m −3 ). Being ultrastrong and ultratough, yet the BC film is also highly flexible and can be folded into desirable shapes. The BC film exhibits a controllable manner of alignment and is highly transparent with modulated optical properties, paving the way to enabling new functionalities in mechanical, electrical, fluidic, photonics, and biocompatible applications.

Wang, Sha↗
DOE OSTI2017

Highly efficient conversion of terpenoid biomass to jet-fuel range cycloalkanes in a biphasic tandem catalytic process

The demand for bio-jet fuels to reduce carbon emissions is increasing substantially in the aviation sector, while the scarcity of high-density jet fuel components limits the use of bio-jet fuels in high-performance aircrafts compared with conventional jet fuels. In this paper, we report a novel biphasic tandem catalytic process (biTCP) for synthesizing cycloalkanes from renewable terpenoid biomass, such as 1,8-cineole. Multistep tandem reactions, including C–O ring opening by hydrolysis, dehydration, and hydrogenation, were carried out in the “one-pot” biTCP. 1,8-Cineole was efficiently converted to p-menthane at high yields (>99%) in the biTCP under mild reaction conditions. Finally, the catalytic reaction mechanism is discussed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Extremely compliant and highly stretchable patterned graphene

Graphene is intrinsically ultra-stiff in its plane. Its huge mechanical mismatch when interfacing with ultra-compliant biological tissues and elastomers (7–9 orders of magnitude difference in stiffness) poses significant challenge in its application to functional devices such as epidermal electronics and sensing prosthesis. We offer a feasible and promising solution to this significant challenge by suitably patterning graphene into a nanomesh. Through systematic coarse-grained simulations, we show that graphene nanomesh can be made extremely compliant with nearly zero stiffness up to about 20% elongation and then remain highly compliant up to about 50% elongation.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Are polynuclear superhalogens without halogen atoms probable? A high-level ab initio case study on triple-bridged binuclear anions with cyanide ligands

The first theoretical exploration of superhalogen properties of polynuclear structures based on pseudohalogen ligand is reported here via a case study on eight triply-bridged [Mg{sub 2}(CN){sub 5}]{sup −} clusters. From our high-level ab initio results, all these clusters are superhalogens due to their high vertical electron detachment energies (VDE), of which the largest value is 8.67 eV at coupled-cluster single double triple (CCSD(T)) level. Although outer valence Green's function results are consistent with CCSD(T) in most cases, it overestimates the VDEs of three anions dramatically by more than 1 eV. Therefore, the combined usage of several theoretical methods is important for the accuracy of purely theoretical prediction of superhalogen properties of new structures. Spatial distribution of the extra electron of high-VDE anions here indicates two features: remarkable aggregation on bridging CN units and non-negligible distribution on every CN unit. These two features lower the potential and kinetic energies of the extra electron respectively and thus lead to high VDE. Besides superhalogen properties, the structures, relative stabilities and thermodynamic stabilities with respect to detachment of CN{sup −1} were also investigated for these anions. The collection of these results indicates that polynuclear structures based on pseudohalogen ligand are promising candidates for new superhalogens with enhanced properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗