Browsing by Author "Huang, Yu-Hsuan"

Now showing 1 - 14 of 14

Finite Element Analysis of Tongue Type Calcaneal Fracture with Open Reduction and Internal Fixation with Locking Plate
(2018-02-01)
Chen, Ching-Hsuan
;
Huang, Yu-Hsuan
;
Hung, Chinghua
;
Chen, Chen-Sheng
;
Chiang, Chao-Ching
Open reduction and internal fixation (ORIF) with plate is the standard treatment for displaced intra-articular calcaneal fractures. We constructed a three-dimensional complete foot finite element model, which was also modified to evaluate the biomechanical effect of Sanders IIB tongue-type calcaneal fracture treated by ORIF with locking plate. We compared plates with locking screws (LSs) and those with non-locking screws (NSs). Static standing was simulated by applying ground reaction force and the pulling force of the Achilles tendon. ORIF with plate using NS or LS provided good stability for Sanders IIB tongue-type calcaneal fracture and might allow light touch weight-bearing in the early postoperative period.
Infrared absorption of gaseous CH2BrOO detected with a step-scan Fourier-transform absorption spectrometer
(2014-10-28)
Huang, Yu-Hsuan
;
Lee, Yuan-Pern
;
應用化學系
;
應用化學系分子科學碩博班
;
Department of Applied Chemistry
CH2BrOO radicals were produced upon irradiation, with an excimer laser at 248 nm, of a flowing mixture of CH2Br2 and O-2. A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to record temporally resolved infrared (IR) absorption spectra of reaction intermediates. Transient absorption with origins at 1276.1, 1088.3, 961.0, and 884.9 cm (1) are assigned to nu(4) (CH2-wagging), nu(6) (O-O stretching), nu(7) (CH2-rocking mixed with C-O stretching), and nu(8) (C-O stretching mixed with CH2-rocking) modes of syn-CH2BrOO, respectively. The assignments were made according to the expected photochemistry and a comparison of observed vibrational wavenumbers, relative IR intensities, and rotational contours with those predicted with the B3LYP/aug-cc-pVTZ method. The rotational contours of nu(7) and nu(8) indicate that hot bands involving the torsional (nu(12)) mode are also present, with transitions 7(0)(1)12(nu)(nu) and 8(0)(1)12(nu)(nu), nu = 1-10. The most intense band (nu(4)) of anti-CH2BrOO near 1277 cm(-1) might have a small contribution to the observed spectra. Our work provides information for directly probing gaseous CH2BrOO with IR spectroscopy, in either the atmosphere or laboratory experiments. (C) 2014 AIP Publishing LLC.
Infrared Absorption Spectrum of the Simplest Criegee Intermediate CH2OO
(2013-04-12)
Su, Yu-Te
;
Huang, Yu-Hsuan
;
Witek, Henryk A.
;
Lee, Yuan-Pern
;
應用化學系
The Criegee intermediates are carbonyl oxides postulated to play key roles in the reactions of ozone with unsaturated hydrocarbons; these reactions constitute an important mechanism for the removal of unsaturated hydrocarbons and for the production of OH in the atmosphere. Here, we report the transient infrared (IR) absorption spectrum of the simplest Criegee intermediate CH2OO, produced from CH2I + O-2 in a flow reactor, using a step-scan Fourier-transform spectrometer. The five observed bands provide definitive identification of this intermediate. The observed vibrational frequencies are more consistent with a zwitterion rather than a diradical structure of CH2OO. The direct IR detection of CH2OO should prove useful for kinetic and mechanistic investigations of the Criegee mechanism.
Infrared absorption spectrum of the simplest deuterated Criegee intermediate CD2OO
(2016-07-28)
Huang, Yu-Hsuan
;
Nishimura, Yoshifumi
;
Witek, Henryk A.
;
Lee, Yuan-Pern
;
應用化學系
We report a transient infrared (IR) absorption spectrum of the simplest deuterated Criegee intermediate CD2OO recorded using a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. CD2OO was produced from photolysis of flowing mixtures of CD2I2, N-2, and O-2 (13 or 87 Torr) with laser light at 308 nm. The recorded spectrum shows close structural similarity with the spectrum of CH2OO reported previously [Y.-T. Su et al., Science 340, 174 (2013)]. The four bands observed at 852, 1017, 1054, and 1318 cm(-1) are assigned to the OO stretching mode, two distinct in-plane OCD bending modes, and the CO stretching mode of CD2OO, respectively, according to vibrational wavenumbers, IR intensities, rotational contours, and deuterium-isotopic shifts predicted with extensive quantum-chemical calculations. The CO-stretching mode of CD2OO at 1318 cm(-1) is blue shifted from the corresponding band of CH2OO at 1286 cm(-1); this can be explained by a mechanism based on mode mixing and isotope substitution. A band near 936 cm(-1), observed only at higher pressure (87 Torr), is tentatively assigned to the CD2 wagging mode of CD2IOO. Published by AIP Publishing.
Infrared identification of the Criegee intermediates syn- and anti-CH3CHOO, and their distinct conformation-dependent reactivity
(2015-05-01)
Lin, Hui-Yu
;
Huang, Yu-Hsuan
;
Wang, Xiaohong
;
Bowman, Joel M.
;
Nishimura, Yoshifumi
The Criegee intermediates are carbonyl oxides that play critical roles in ozonolysis of alkenes in the atmosphere. So far, the mid-infrared spectrum of only the simplest Criegee intermediate CH2OO has been reported. Methyl substitution of CH2OO produces two conformers of CH3CHOO and consequently complicates the infrared spectrum. Here we report the transient infrared spectrum of syn- and anti-CH3CHOO, produced from CH3CHI + O-2 in a flow reactor, using a step-scan Fourier-transform spectrometer. Guided and supported by high-level full-dimensional quantum calculations, rotational contours of the four observed bands are simulated successfully and provide definitive identification of both conformers. Furthermore, anti-CH3CHOO shows a reactivity greater than syn-CH3CHOO towards NO/NO2; at the later period of reaction, the spectrum can be simulated with only syn-CH3CHOO. Without NO/NO2, anti-CH3CHOO also decays much faster than syn-CH3CHOO. The direct infrared detection of syn-and anti-CH3CHOO should prove useful for field measurements and laboratory investigations of the Criegee mechanism.
Infrared spectrum of the simplest Criegee intermediate CH2OO at resolution 0.25 cm(-1) and new assignments of bands 2 nu(9) and nu(5)
(2015-06-07)
Huang, Yu-Hsuan
;
Li, Jun
;
Guo, Hua
;
Lee, Yuan-Pern
;
應用化學系
The simplest Criegee intermediate CH2OO is important in atmospheric chemistry. It has been detected in the reaction of CH2I + O-2 with various spectral methods, including infrared spectroscopy; infrared absorption of CH2OO was recorded at resolution 1.0 cm(-1) in our laboratory. We have improved our system and recorded the infrared spectrum of CH2OO at resolution 0.25 cm(-1) with rotational structures partially resolved. Observed vibrational wavenumbers and relative intensities are improved from those of the previous report and agree well with those predicted with quantum-mechanical calculations using the MULTIMODE method on an accurate potential energy surface. Observed rotational structures also agree with the simulated spectra according to theoretical predictions. In addition to derivation of critical vibrational and rotational parameters of the vibrationally excited states to confirm the assignments, the spectrum with improved resolution provides new assignments for bands 2 nu(9) at 1234.2 cm(-1) and nu(5) at 1213.3 cm(-1); some hot bands and combination bands are also tentatively assigned. (C) 2015 AIP Publishing LLC.
Internal energy of HCl upon photolysis of 2-chloropropene at 193 nm investigated with time-resolved Fourier-transform spectroscopy and quasiclassical trajectories
(2008-12-14)
Chang, Chih-Min
;
Huang, Yu-Hsuan
;
Liu, Suet-Yi
;
Lee, Yuan-Pern
;
Pombar-Perez, Marta
Following photodissociation of 2-chloropropene (H(2)CCClCH(3)) at 193 nm, vibration-rotationally resolved emission spectra of HCl (upsilon <= 6) in the spectral region of 1900-2900 cm(-1) were recorded with a step-scan time-resolved Fourier-transform spectrometer. All vibrational levels show a small low-J component corresponding to similar to 400 K and a major high-J component corresponding to 7100-18 700 K with average rotational energy of 39 +/-(11)(3) kJ mol(-1). The vibrational population of HCl is inverted at upsilon=2, and the average vibrational energy is 86 +/- 5 kJ mol(-1). Two possible channels of molecular elimination producing HCl+propyne or HCl+allene cannot be distinguished positively based on the observed internal energy distribution of HCl. The observed rotational distributions fit qualitatively with the distributions of both channels obtained with quasiclassical trajectories (QCTs), but the QCT calculations predict negligible populations for states at small J. The observed vibrational distribution agrees satisfactorily with the total QCT distribution obtained as a weighted sum of contributions from both four-center elimination channels. Internal energy distributions of HCl from 2-chloropropene and vinyl chloride are compared.
Manifestations of Torsion-CH Stretch Coupling in the Infrared Spectrum of CH3OO
(2016-07-14)
Hsu, Kuo-Hsiang
;
Huang, Yu-Hsuan
;
Lee, Yuan-Pern
;
Huang, Meng
;
Miller, Terry A.
With a step-scan Fourier-transform spectrometer we recorded temporally resolved infrared absorption spectra of CH3OO radicals that were produced upon irradiation of CH3COCH3 and O-2 at 193 nm in a flowing mixture. At a resolution of 0.15 cm(-1), the rotational structure of the nu(2) band of CH3OO near 2954.4 cm(-1) is partially resolved and shows an unexpectedly broadened, and somewhat distorted, Q-branch. A 4D model Hamiltonian, consisting of three CH stretches and the methyl torsion, was developed to explore the origins of this broadening. The vibrational progressions predicted by the model Hamiltonian and the rotational contours of the nu(2) band, based on experimental ground-state rotational parameters and their values scaled by their calculated ratios for the upper state, produced simulations in satisfactory agreement with the observed spectrum. These results provide new inSight into the vibrational couplings in CH3OO.
Modeling the CH Stretch/Torsion/Rotation Couplings in Methyl Peroxy (CH3OO)
(2017-12-21)
Huang, Meng
;
Miller, Terry A.
;
McCoy, Anne B.
;
Hsu, Kuo-Hsiang
;
Huang, Yu-Hsuan
The manifestations of CH stretch/torsion/ rotation coupling in the region of the CH stretch fundamentals are explored in the CH3OO radical. Following our earlier study of the fundamental in the totally symmetric CH stretch (the fundamental), this work focuses on the other two CH stretch fundamentals, nu(1) and nu(9), which would be degenerate in the absence of a barrier in the potential along the methyl torsion coordinate. The simplest model, which assumes a decoupling of the CH stretch vibrations from the torsion, fails to reproduce several important features of the spectrum. Specifically, the absence of a strong peak around the origin of the nu(1), fundamental and broadening of the strong peak near the origin in the observed spectrum of the nu(9) fundamental are not captured by this model. The origins of these features are explored through two more sophisticated treatments of the torsion/CH stretch couplings. In the first, a four-dimensional potential based on the three CH stretches and the torsion is developed and shown to reproduce both of these features. On the basis of the results of these calculations, the calculated parameters are adjusted to simulate the recorded spectrum. To further explore the torsion/CH stretch couplings in CH3OO, a 9-state model Hamiltonian is developed and discussed. The implications of various types of couplings on the observed energy level patterns are also discussed.
Photocatalytic study of Zinc Oxide with bismuth doping prepared by spray pyrolysis
(2015-09-01)
Lin, Tzu-Yang
;
Hsu, Yu -Ting
;
Lan, Wen-How
;
Huang, Chien-Jung
;
Chen, Lung-Chien
The unintentionally doped and bismuth (Bi) doped zinc oxide (ZnO) films were prepared by spray pyrolysis at 450 degrees C with zinc acetate and bismuth nitrate precursor. The n-type conduction with concentration 6.13 x10(16)cm(-3) can be observed for the unintentionally doped ZnO. With the increasing of bismuth nitrate concentration in precursor, the p-type conduction can be observed. The p-type concentration 4.44x10(17)cm(-3) can be achieved for the film with the Bi/Zn atomic ratio 5% in the precursor. The photoluminescence spectroscopy with HeCd laser light source was studied for films with different Bi doping. The photocatalytic activity for the unintentionally doped and Bi-doped ZnO films was studied through the photodegradation of Congo red under UV light illumination. The effects of different Bi contents on photocatalytic activity are studied and discussed. Results show that appropriate Bi doping in ZnO can increase photocatalytic activity.
Photodissociation Dynamics of Benzaldehyde (C(6)H(5)CHO) at 266, 248, and 193 nm
(2011-11-04)
Bagchi, Arnab
;
Huang, Yu-Hsuan
;
Xu, Z. F.
;
Raghunath, P.
;
Lee, Yuan T.
The photodissociation of gaseous benzaldehyde (C(6)H(5)CHO) at 193, 248, and 266 nm using multimass ion imaging and step-scan time-resolved Fourier-transform infrared emission techniques is investigated. We also characterize the potential energies with the CCSD(T)/6-311+G(3df,2p) method and predict the branching ratios for various channels of dissociation. Upon photolysis at 248 and 266 nm, two major channels for formation of HCO and CO, with relative branching of 0.37:0.63 and 0.20:0.80, respectively, are observed. The C(6)H(5)+HCO channel has two components with large and small recoil velocities; the rapid component with average translational energy of approximately 25 kJ mol(-1) dominates. The C(6)H(6)+CO channel has a similar distribution of translational energy for these two components. IR emission from internally excited C(6)H(5)CHO, nu(3) (nu = 1) of HCO, and levels nu <= 2, J <= 43 of CO are observed; the latter has an average rotational energy of approximately 13 kJ mol(-1) and vibrational energy of approximately 6 kJ mol(-1). Upon photolysis at 193 nm, similar distributions of energy are observed, except that the C(6)H(5)+HCO channel becomes the only major channel with a branching ratio of 0.82 +/- 0.10 and an increased proportion of the slow component; IR emission from levels nu(1) (nu = 1) and nu(3) (nu = 1 and 2) of HCO and nu <= 2, J <= 43 of CO are observed; the latter has an average energy similar to that observed in photolysis at 248 nm. The observed product yields at different dissociation energies are compared to statistical-theory predicted results based on the computed singlet and triplet potential-energy surfaces.
Photodissociation Dynamics of Benzaldehyde (C6H5CHO) at 266, 248, and 193 nm
(2011-11-04)
Bagchi, Arnab
;
Huang, Yu-Hsuan
;
Xu, Z. F.
;
Raghunath, P.
;
Lee, Yuan T.
The photodissociation of gaseous benzaldehyde (C6H5CHO) at 193, 248, and 266 nm using multimass ion imaging and step-scan time-resolved Fourier-transform infrared emission techniques is investigated. We also characterize the potential energies with the CCSD(T)/6-311+G(3df,2p) method and predict the branching ratios for various channels of dissociation. Upon photolysis at 248 and 266 nm, two major channels for formation of HCO and CO, with relative branching of 0.37:0.63 and 0.20:0.80, respectively, are observed. The C6H5+HCO channel has two components with large and small recoil velocities; the rapid component with average translational energy of approximately 25 kJ mol(-1) dominates. The C6H6+CO channel has a similar distribution of translational energy for these two components. IR emission from internally excited C6H5CHO, nu(3) (nu = 1) of HCO, and levels nu <= 2, J <= 43 of CO are observed; the latter has an average rotational energy of approximately 13 kJ mol(-1) and vibrational energy of approximately 6 kJ mol(-1). Upon photolysis at 193 nm, similar distributions of energy are observed, except that the C6H5+HCO channel becomes the only major channel with a branching ratio of 0.82 +/- 0.10 and an increased proportion of the slow component; IR emission from levels nu(1) (nu = 1) and nu(3) (nu = 1 and 2) of HCO and nu <= 2, J <= 43 of CO are observed; the latter has an average energy similar to that observed in photolysis at 248 nm. The observed product yields at different dissociation energies are compared to statistical-theory predicted results based on the computed singlet and triplet potential-energy surfaces.
Simultaneous Infrared Detection of the ICH2OO Radical and Criegee Intermediate CH2OO: The Pressure Dependence of the Yield of CH2OO in the Reaction CH2I + O-2
(2015-11-19)
Huang, Yu-Hsuan
;
Chen, Li-Wei
;
Lee, Yuan-Pern
;
應用化學系
;
應用化學系分子科學碩博班
The simplest Criegee intermediate CH2OO, important in atmospheric reactions, has been recently produced from the reaction of CH2I + O-2 and detected with various methods. In this reaction, the yield of CH2OO decreases with increasing pressure because of the stabilization of the adduct ICH2OO, but no definitive spectral identification of ICH2OO has been reported. We recorded the infrared spectrum of ICH2OO using the same reaction under high pressure; the spectrum agrees with that simulated according to theoretical predictions. With direct detection of both CH2OO and ICH2OO, we determined the pressure dependence of the yield of CH2OO. The yield of CH2OO near 1 atm is greater than previously reported values, which might have significant consequences in atmospheric chemistry.
Transient Infrared Absorption Spectra of Reaction Intermediates Detected with a Step-scan Fourier-transform Infrared Spectrometer
(2014-01-01)
Huang, Yu-Hsuan
;
Chen, Jin-Dah
;
Hsu, Kuo-Hsiang
;
Chu, Li-Kang
;
Lee, Yuan-Pern
Our group has utilized a step-scan FTIR spectrometer operating in the absorption mode to characterize transient species in chemical reactions upon photo-irradiation of gaseous mixtures in a multipass White cell. The operational temporal resolution is typically 1-10 s with spectral resolution 0.1-4 cm(-1), depending on conditions. The acquisition of both ac- and dc-coupled signals enables an extraction of minute changes in the large background signal to attain a typical detectable absorbance variation greater than 1 x 10(-4). By consideration of reaction mechanisms and comparison of vibrational wavenumbers, IR intensities, and rotational contours predicted with theoretical calculations, we have assigned IR absorption bands of many important atmospheric free radicals and unstable species including their conformers, such as ClCO, ClSO, ClCS, ClCOOH, CH3SO2, CH3SOO, CH3OSO, CH3SO, CH3OO, CH3C(O)OO, CH2OO C6H5CO, C6H5SO2, and C6H5C(O)OO. The advantages and limitations of this technique to perform spectral and kinetic investigations of transient species in chemical reactions are discussed.