A5085065724- Liquid Crystal Research Advancements
- Organic Electronics and Photovoltaics
- Photonic Crystals and Applications
- Organic Light-Emitting Diodes Research
- Diffusion Coefficients in Liquids
- Surfactants and Colloidal Systems
- Astrophysics and Cosmic Phenomena
- Phase Equilibria and Thermodynamics
- Molecular spectroscopy and chirality
- Luminescence and Fluorescent Materials
- Synthesis and Properties of Aromatic Compounds
- Gamma-ray bursts and supernovae
- Photonic and Optical Devices
- Material Dynamics and Properties
- Semiconductor Lasers and Optical Devices
- Thermodynamic properties of mixtures
- Photochromic and Fluorescence Chemistry
- Nonlinear Dynamics and Pattern Formation
- Photochemistry and Electron Transfer Studies
- Conducting polymers and applications
- Adsorption, diffusion, and thermodynamic properties of materials
- Synthesis and properties of polymers
- Advanced Materials and Mechanics
- Advanced Optical Imaging Technologies
- Solar and Space Plasma Dynamics
Gansu Great Wall Electrical and Electronics Engineering Research Institute
2024
University of Chinese Academy of Sciences
2022-2024
Institute of High Energy Physics
2022-2024
Chinese Academy of Sciences
2022-2024
University of Rochester
2012-2023
Energetics (United States)
2003-2018
Goddard Space Flight Center
1996-2014
Universities Space Research Association
2014
Kodak (United States)
1997-2008
Anhui University
2007
The first series of monodisperse chiral oligofluorenes was synthesized and characterized. Chain length found to play an important role in solid morphology. Whereas dimer through tetramer are amorphous, pentamer hexadecamer all show cholesteric mesomorphism with varying degrees morphological stability against crystallization. Pristine spin-cast films, approximately 90 nm thickness, amorphous but exhibit pronounced circular dichroism highly efficient circularly polarized fluorescence,...
Tracer diffusivities are reported for argon, krypton, xenon, methane, carbon tetrachloride, and tetraalkyltins (methyl, ethyl, n-propyl, n-butyl) in normal octane, decane, tetradecane temperatures ranging from 25 to 160 °C. The were measured by the Taylor dispersion method. With temperature-dependent solvent diameters fitted tracer diffusivity of one solutes, a rough-hard-sphere theory predicts well observed all other solutes n-octane and, at high temperatures, n-decane (60–160 °C)...
ADVERTISEMENT RETURN TO ISSUEPREVArticleThermodynamics of solution nonpolar gases in a fused salt. Hydrophobic bonding behavior nonaqueous systemD. Fennell Evans, Shaw-Horng Chen, George W. Schriver, and Edward M. ArnettCite this: J. Am. Chem. Soc. 1981, 103, 2, 481–482Publication Date (Print):January 1, 1981Publication History Published online1 May 2002Published inissue 1 January 1981https://doi.org/10.1021/ja00392a049Request reuse permissionsArticle Views599Altmetric-Citations182LEARN...
Novel nonafluorenes with a varying extent of pendant chirality were synthesized for an investigation the origins chiroptical activities in neat films. Thermal annealing 4-microm-thick sandwiched films and 90-nm-thick spin-cast films, all on surface-treated substrates, produced monodomain glassy characterized as right-handed cholesteric stack helical pitch length ranging from 180 to 534 nm 252 1151 nm, respectively. The observed strong circular dichroism (CD) g(e) functions single-substrate...
A series of spiro-linked oligofluorenes were synthesized that exhibit blue emission with photoluminescence quantum yields in some cases exceeding 0.50 neat spin-coated films. Differential scanning calorimetry revealed highly variable glass transition temperatures. longer conjugation length is desired for better stability against thermally activated crystallization, and a shorter pendant higher temperature at given length. In contrast to poly(2,7-(9,9-di-n-octylfluorene)), prolonged heating...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDiffusion of crown ethers in alcoholsHang Chang Chen and Shaw Horng ChenCite this: J. Phys. Chem. 1984, 88, 21, 5118–5121Publication Date (Print):October 1, 1984Publication History Published online1 May 2002Published inissue 1 October 1984https://pubs.acs.org/doi/10.1021/j150665a063https://doi.org/10.1021/j150665a063research-articleACS PublicationsRequest reuse permissionsArticle Views761Altmetric-Citations148LEARN ABOUT THESE METRICSArticle Views...
Abstract Simulation studies of the Earth's radiation belts and ring current are very useful in understanding acceleration, transport, loss energetic particles. Recently, Comprehensive Ring Current Model (CRCM) Radiation Belt Environment (RBE) model were merged to form a Inner Magnetosphere‐Ionosphere (CIMI) model. CIMI solves for many essential quantities inner magnetosphere, including ion electron distributions belts, plasmaspheric density, Region 2 currents, convection potential,...
Monodisperse oligo(fluorene)s have been successfully employed for the construction of polarized blue organic light‐emitting diodes. Uniaxial alignment is accomplished by spin‐casting onto a rubbed layer with subsequent thermal annealing. The resultant films yield best set performance data ever reported in terms emission dichroic ratio, luminance yield, and chromaticity (see Figure).
Reconnection is accepted as an important process for driving the solar wind/magnetospheric interaction although it not fully understood. In particular, reconnection northward interplanetary magnetic field (IMF) at high‐latitudes tailward of cusp, has received little attention in comparison with equatorial southward IMF. Using Hawkeye data we present first direct observations high‐latitude magnetopause (75°) during IMF form sunward flowing protons. This flow nearly aligned, approximately...
The first series of monodisperse glass-forming, nematic oligofluorenes was synthesized following a divergent−convergent approach. Both chain length and pendant structure were found to affect solid morphology phase transition temperatures. With optimized structural parameters, Tg close 150 °C Tc beyond 375 achieved. This material class is characterized by its ability form monodomain glassy films via spin-coating, thermal annealing at 10 20 above for 15−30 min, cooling room temperature without...
Abstract Light‐emitting conjugated oligomers comprising anthracene, naphthalene, and fluorene units have been synthesized to investigate three configurations of blue organic light‐emitting diodes (OLEDs) that are designed identify the origins device instability. The transient OLED technique is employed measure hole mobilities, which found be 3.1 × 10 –4 , 8.9 –5 3.6 cm 2 V –1 s for different blue‐light‐emitting model compounds with varying content. A higher mobility through emissive layer...
A heptafluorene lightly doped with monodisperse conjugated oligomers is used for the first demonstration of organic polarized (see Figure) light‐emitting diodes utilizing Förster energy transfer. Emission blue‐green, green, red, and white light accomplished a turn‐on voltage < 4 V, peak polarization ratios up to 26, integrated 19, luminance yields 6.4 cd –1 .
A heptafluorene, F(Pr)5F(MB)2, a dodecafluorene, F(MB)10F(EH)2, and poly(9,9'-dioctylfluorene), PFO, were used to prepare field-effect transistors. Monodomain polydomain glassy-nematic films as well glassy-amorphous prepared for the measurement of hole mobility. In monodomain film, μ∥ value is determined by chain length in oligofluorene persistence polyfluorene. Mobility film lies between μ⊥ film. Amorphous possess lowest mobility all presumably because geometric energetic disorder. The OFET...
The effect of thermal annealing on photovoltaic devices comprising poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM) with thicknesses up to 1200 nm was investigated. Without annealing, the efficiency as-prepared decreased increasing active layer thickness, reflecting largely a reduction in short-circuit current density and an inverse photocurrent spectral response. Thermal full found substantially recover thick-film device efficiencies while reducing thin-film...
Tracer diffusion measurements taken over a wide range of temperature (25.0–142.7° C) are reported for nine solutes (Ar, CH4, Kr, Xe, R4 Sn: R = Me, Et, n-Pr, n-Bu) in cyclohexane. The were made Taylor dispersion apparatus modified pressurization and control. Rough-hard-sphere theory, which the coefficient is product constant rotational factor, Enskog’s diffusivity hard spheres, computer-generated backscattering coefficient, agrees well with observed results. theory furnishes new insights...
Comprising hole- and electron-transporting moieties with flexible linkages, representative non-conjugated bipolar hybrids have been synthesized characterized for a demonstration of their potential use as host materials the fabrication phosphorescent organic light-emitting diodes. The advantages this material class include solution processing into amorphous films elevated glass transition temperatures, stability against phase separation crystallization, provision LUMO/HOMO levels triplet...
Very recently, the Large High Altitude Air Shower Observatory (LHAASO) reported observation of very early TeV afterglow brightest-of-all-time GRB 221009A, recording highest photon statistics in band ever from a gamma-ray burst. We use this unique to place stringent constraints on an energy dependence speed light vacuum, manifestation Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that 95% confidence level lower limits QG scales are...
A novel series of monodisperse conjugated oligomers were synthesized by inserting varied segments into blue-emitting oligofluorenes to complete the color gamut light emission. Quantum mechanical calculations revealed that electron transition dipoles lie largely parallel long molecular axes central responsible for The orientational order parameter characterizing alignment in thermally processed glassy-nematic films was evaluated at 0.77 0.87 UV−vis absorption dichroism. With an emission...
Polymers containing 6- and 7-substituted coumarin moieties were prepared as photoalignment films through linearly polarized UV irradiation to a varying fluence for an investigation of liquid crystal orientation. Model monomers dimers also synthesized characterized part novel approach the interpretation orientation in terms monomer conversion. The experimental results conversion function used validate first-order kinetics with exponentially decaying rate constant reaction proceeds. A kinetic...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTracer diffusion of crown ethers in n-decane and n-tetradecane: an improved correlation for binary systems involving normal alkanesHang Chang Chen Shaw Horng ChenCite this: Ind. Eng. Chem. Fundamen. 1985, 24, 2, 187–192Publication Date (Print):May 1, 1985Publication History Published online1 May 2002Published inissue 1 1985https://doi.org/10.1021/i100018a009RIGHTS & PERMISSIONSArticle Views116Altmetric-Citations68LEARN ABOUT THESE METRICSArticle...
Abstract Diffusion coefficients of argon, krypton, xenon, methane, carbon tetrachloride and the tetraalkyltins (methyl through butyl) were measured in methanol, 1‐butanol 1‐octanol over temperature range 298 to 433 K. With temperature‐dependent solvent diameters fitted from tracer diffusivity one solutes, a rough‐hard‐sphere theory predicts well observed density which hard‐sphere computer simulations are available. The Wilke‐Chang correlation diffusion higher alcohols with an average error...
A series of fully spiro-configured terfluorenes were synthesized and characterized to be amorphous materials showing a Tg 296 °C with dendritic aromatic pendants, the highest value ever reported for organic molecular systems. X-ray single-crystal analysis key structural moieties indicated nearly perpendicular orientations at all spiro-links. The spectroscopic comparison solid film dilute solution suggested absence aggregates in ground state no increase torsion angle an increasing volume...