A5073390793- Laser-Matter Interactions and Applications
- Advanced Fiber Laser Technologies
- Polymer crystallization and properties
- biodegradable polymer synthesis and properties
- Advanced X-ray Imaging Techniques
- Photonic Crystal and Fiber Optics
- Laser-Plasma Interactions and Diagnostics
- Photorefractive and Nonlinear Optics
- Cavitation Phenomena in Pumps
- Fluid Dynamics Simulations and Interactions
- Solid State Laser Technologies
- Water Systems and Optimization
- Photonic and Optical Devices
- Advanced Polymer Synthesis and Characterization
- Carbon Nanotubes in Composites
- Hydraulic and Pneumatic Systems
- Advanced Fluorescence Microscopy Techniques
- Spectroscopy and Quantum Chemical Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Thermal and Kinetic Analysis
- Polymer Nanocomposites and Properties
- Microplastics and Plastic Pollution
- Refrigeration and Air Conditioning Technologies
- Rheology and Fluid Dynamics Studies
- Electrospun Nanofibers in Biomedical Applications
Pennsylvania State University
2021-2025
Aerospace Information Research Institute
2022-2024
Chinese Academy of Sciences
2022-2024
Yunnan University
2023-2024
University of Chinese Academy of Sciences
2022-2023
Florida A&M University - Florida State University College of Engineering
2015-2022
University of California, San Diego
2022
Beijing Institute of Power Machinery (China)
2019-2021
Commercial Aircraft Corporation of China (China)
2020
North China University of Science and Technology
2019
Abstract We demonstrate a novel flat-field, dual-optic imaging EUV—soft X-ray spectrometer and monochromator that attains an unprecedented throughput efficiency exceeding 60% by design, along with superb spectral resolution of λ /Δ > 200 accomplished without employing variable line spacing gratings. Exploiting the benefits conical diffraction geometry, optical system is globally optimized in multidimensional parameter space to guarantee optimal performance over broad range while...
We demonstrate the highest flux tabletop source of coherent soft X-rays to date, driven by a single-stage 10 mJ Ti:sapphire regenerative amplifier at 1 kHz.We first down-convert laser 1.3 µm using parametric amplifier, before up-converting it high harmonic generation in high-pressure, phase matched, hollow waveguide geometry.The resulting optimally matched broadband spectrum extends 200 eV, with X-ray photon > 6 photons/pulse/1% bandwidth kHz, corresponding 9 photons/s/1% bandwidth, or...
Abstract Prior work revealed distinct differences in the X‐ray diffraction patterns of poly(butylene succinate) (PBS) melt‐crystallized at different temperatures, regarding number, width, and position peaks, detected isotropic samples. To further evaluate whether observed are caused by a change unit cell, or solely due to crystal sizes perfection, fiber solid‐state oriented PBS acquired analyzed. The data reveal that crystallized high supercooling melt 20 °C contains crystals with enlarged...
We propose a new technique for phase matching high harmonic generation that can be used generating bright, tabletop, tunable, and coherent x-ray sources at keV photon energies. A weak quasi-cw counterpropagating field induces sinusoidal modulation in the of emitted harmonics correcting large plasma-induced mismatch. develop an analytical model describes this grating-assisted predicts very modest intensities (<10(10) W/cm2) fields are required implementation.
Rapidly melt-crystallized polyethylenes with acetal groups (−O–CH2–O−) precisely spaced by 12, 18, 19, or 23 methylene backbone carbons exhibit two reorganizations and three melting endotherms on heating at relatively low rates. Real-time wide-angle X-ray diffraction (WAXD) experiments further confirm that these transitions are associated a reorganization to different crystalline structure. The differential scanning calorimetry of the initially formed disordered (or hexagonal) phases,...
Isothermal crystallization of polyamide 6 (PA6) was studied using a state-of-the-art modified fast scanning calorimetry (FSC) chip over wide temperature range. Microfocus FTIR spectroscopy carried out to collect temperature-dependent spectra PA6 directly on the FSC chip. The changes observed in amide- and methylene-related bands provide direct evidence three crystalline modifications from melt crystallization. melt-crystallized found develop mesomorphic β-phase below 105 °C α-phase above 150...
Polyamide 66 (PA66) and polyamide 6 (PA6) share many comparable properties due to their similar chemical structures. However, crystallization kinetics morphological differences are not as well understood other properties. This work establishes the morphology of additive-free PA66 PA6 at high undercooling conditions using a modified fast scanning calorimetry technique. Two polyamides show profile morphology, but transitions associated with polymorphs occur different temperatures. Regarding...
Abstract Non‐isothermal crystallization kinetics has been traditionally predicted using the Nakamura crystal growth model, which is an integral form of Avrami equation under assumption that non‐isothermal can be explained a series infinitesimal isothermal steps. However, model often overpredicts fraction near end because ignoring slower secondary kinetics. In this study, dual proposed to capture both primary and poly(ether ether ketone) (PEEK). First, PEEK monitored at five constant cooling...
Poly(ethylene tridecanodiate), also known as poly(ethylene brassylate) (PEB), is a short–long aliphatic polyester obtained from renewable source. Cooled the melt by differential scanning calorimetry or fast calorimetry, PEBs in range of molar mass between 27000 and 188000 Da display single crystallization exotherms. On heating, exhibit two major melt-recrystallization events at ∼40 ∼60 °C prior to their final melting ∼70 °C. WAXD patterns collected situ during heating rule out any...
We review recent experimental and theoretical work on the use of counterpropagating light to enhance high-order harmonic generation through all-optical quasi-phase matching. Also presented is a new technique for measuring coherence high harmonics in nonlinear medium. This information crucial understanding process over extended distances, as well effective enhancement using matching techniques.
High molar mass polyethylenes with bromine atoms placed on each and every 21st, 19th, 15th, or 9th backbone carbon crystallize into two distinctive layered polymorphs by changing undercooling. Crystallization at low temperatures produces Form I, a planar all-trans conformation, while higher gauche conformers set for bonds adjacent to the methine due close intermolecular staggering of bromines resulting in herringbone II structure. In this work, sharp range isothermal crystallization...
Intervals of shear flow that stretch polymer chains form flow-induced precursors which accelerate crystallization and transform the crystalline morphology from isotropic spherulites to anisotropic structures. The two commercial samples isotactic polypropylene with nearly identical molecular weight distributions, differing in concentrations catalyst residue particles, was investigated by using dynamic rheology ex situ Synchrotron X-ray scattering. Upon application flow, sample higher particle...
Microbubble drag reduction on the axisymmetric body is experimentally investigated in turbulent water tunnel. Microbubbles are created by injecting compressed air through porous medium with various average pore sizes. The morphology of microbubble flow and size distribution observed high-speed visualization system. Drag measurements obtained balance which presented as function void ratio. results show that when injection rate high, uniformly dispersed coalesced into an layer larger increment...
Under isothermal crystallization (Tc) from the melt, polyacetals spaced by 12, 18, 19, or 23 methylenes develop two three distinctive layered polymorphs. The polymorphs formed in lowest Tc range are kinetically favored (hexagonal and Form I) characterized highly nucleated small axialites up to very close their melting point. In higher of Tc, a thermodynamically more stable II develops that melts at 5–8 degrees temperatures forms large spherulites. I overlap Tc. While overall kinetics display...
Polyethylenes with halogens placed on each and every 21st, 15th, or ninth backbone carbon display crystallization patterns enabled by the size of halogen changing kinetics. The different structures have been identified from X-ray combined a detailed analysis infrared spectra series containing F, Cl, Br atoms that were either fast isothermally crystallized melt. Under both modes, all specimens develop layered crystallites accommodate 5-9 repeating units along chain's axis. intermolecular...