Thou Jen Whang

Laser-Induced Silver Nanoparticles on Titanium Oxide for Photocatalytic Degradation of Methylene Blue

Silver nanoparticles doped on titanium oxide (TiO2) were produced by laser-liquid interaction of silver nitrate (AgNO3) in isopropanol. Characteristics of Ag/TiO2 (Ag doped TiO2) nanoparticles produced by the methods presented in this article were investigated by XRD, TEM, SEM, EDX, and UV-Vis. From the UV-Vis measurements, the absorption of visible light of the Ag/TiO2 photocatalysts was improved (additional absorption at longer wavelength in visible light region) obviously. The photocatalytic efficiency of Ag/TiO2 was tested by the degradation of methylene blue (MB) in aqueous solution. A maximum of 82.3% MB degradation is achieved by 2.0 wt% Ag/TiO2 photocatalyst under 2 h illumination with a halogen lamp.

Determination of the long-range potential and dissociation energy of the 1 3Δg state of Na2

The 1 3Δg state of Na2 has been studied extensively by both filtered fluorescence and ionization detection and analyzed by both Dunham‐type expansion and near‐dissociation expansion (NDE) models in the analysis. Our observations have covered 99.998% of the potential well depth with the outermost Rydberg–Klein–Rees (RKR) turning point at 28.02 A. NDE analysis gives Te=28 032.468 (±0.021) cm−1, De=7162.436 (±0.021) cm−1, and Re=3.463 81 (±0.000 28) A. Significant long‐range behavior in the near dissociation levels has been observed. Fitting of the RKR turning points gives the long‐range coefficients C5=1.388 (±0.031)×106 cm−1 A5 and C6=0.4008 (±0.0046)×108 cm−1 A6. These newly observed results show reasonable agreement with recent theoretical calculations.

Electrodeposition of Palladium–Tin Alloys from 1-Ethyl-3-methylimidazolium Chloride–Tetrafluoroborate Ionic Liquid for Ethanol Electro-Oxidation

Electrodeposition of palladium-tin alloys from 1-ethyl-3-ethylimidazolium chloride―tetrafluoroborate ionic liquid was studied at 120°C. Sn(II) chloride reacts spontaneously with Pd(II) chloride, producing Sn(IV) and Pd nanoparticles. Solutions containing Sn(IV) and Pd(II) were used for potentiostatic electrodeposition of Pd-Sn. The composition of the Pd-Sn electrodeposits varied with the solution composition and deposition potential. Different alloy phases were observed with X-ray diffraction measurements. Whereas the Pd-rich Pd-Sn solid solution deposits are composed of compact nodules, the Sn-rich intermetallic Pd―Sn deposits are composed of polyhedral crystals of various phases. Compared to Pd-coated electrodes, Pd-Sn solid-solution-coated electrodes show enhanced ethanol electro-oxidation efficiency and stability in alkaline aqueous solutions. As Sn content increased, new Pd/Sn intermetallic phases formed, resulting in reduced catalytic efficiency for ethanol oxidation.

New spectroscopic data, spin-orbit functions, and global analysis of data on the AΣu+1 and bΠu3 states of Na2

The lowest electronically excited states of Na2 are of interest as intermediaries in the excitation of higher states and in the development of methods for producing cold molecules. We have compiled previously obtained spectroscopic data on the AΣu+1 and bΠu3 states of Na2 from about 20 sources, both published and unpublished, together with new sub-Doppler linewidth measurements of about 15 000 A←X transitions using polarization spectroscopy. We also present new ab initio results for the diagonal and off-diagonal spin-orbit functions. The discrete variable representation is used in conjunction with Hund’s case a potentials plus spin-orbit effects to model data extending from v=0 to very close to the 3S2+3P1∕22 limit. Empirical estimates of the spin-orbit functions agree well with the ab initio functions for the accessible values of R. The potential function for the A state includes an exchange potential for S+P atoms, with a fitted coefficient somewhat larger than the predicted value. Observed and calculat...

A study of financial insolvency prediction model for life insurers

The objective of insurer supervision is to monitor the financial solvency of companies and to protect the rights of consumers. Improving the related legislation and regulatory policy are also the goals of supervision. The purpose of this study is to evaluate the financial soundness by using the rating systems of the CAMEL and the risk-based capital (RBC) models. Moreover, it is to explore whether insurers exit a significance difference of financial stability or not between domestic and foreign branch life insurers. This study constructed an efficient insolvency prediction model and showed that the artificial neural network was more excellent for classification than the traditional discriminant method since the artificial neural networks accurate discrimination rate of 95.2% with a lower Type I error of 0.0274 and Type II error of 0.0769.

UV-Irradiated Photocatalytic Degradation of Nitrobenzene by Titania Binding on Quartz Tube

A new method for UV-irradiated degradation of nitrobenzene by titania photocatalysts was proposed, titania nanoparticles were coated on a quartz tube through the introduction of tetraethyl orthosilicate into the matrix. The dependence of nitrobenzene photodegradation on pH, temperature, concentration, and air feeding was discussed, and the physical properties such as the activation energy, entropy, enthalpy, adsorption constant, and rate constant were acquired by conducting the reactions in a variety of experimental conditions. The optimum efficiency of the photodegradation with the nitrobenzene residue as low as 8.8% was achieved according to the experimental conditions indicated. The photodegradation pathways were also investigated through HPLC, GC/MS, ion chromatography (IC), and chemical oxygen demand (COD) analyses.

Analysis of the Na2 23Σg+→a3Σu+ continua: Potentials and transition moment function

The repulsive a 3Σu+ state potential of the Na2 molecule is determined by applying the IPA (inverse perturbation approach) of V. S. Ivanov and V. B. Sovkov [Chem. Phys. 213, 295 (1996)] to the analysis of the Na2 2 2Σg+ (v=15, N=27, and v=5, N=39)→a 3Σu+ continua observed in the work of T. J. Whang et al. [J. Mol. Spectrosc. 160, 411 (1993)]. The resulting a 3Σu+ state potential is close to the ab initio potential within the experimental error, but its right branch deviates from the RKR–Le Roy–Bernstein potential function of the a 3Σu+ state shallow well reported in E.-J. Friedman-Hill and R. W. Field [J. Chem. Phys. 96, 2444 (1992)]. The transition moment function M(R) of the 2 3Σg+−a 3Σu+ transition is also obtained from the analysis of the spectra and compared to the ab initio one. The same 2 3Σg+ (v=15, N=27)→a 3Σu+ experimental spectrum is used for investigating abilities of the WKB nodes method, the FCF phase method, and the method of the accurate equation for the potential in terms of the transitio...

Optical–optical double resonance spectroscopy of the 4 1Σ+g ‘‘shelf’’ state of Na2 using an ultrasensitive ionization detector

The 4 1Σ+g ‘‘shelf’’ state of Na2 was extensively investigated using optical–optical double resonance spectroscopy and an ultrasensitive ionization detector. A total of 179 vibrational levels‐(0≤v≤127 are from previous work by using filter‐photomultiplier tube fluorescence detection) were observed in this state, which covered more than 99.8% of the well depth. The Rydberg–Klein–Rees (RKR) potential energy curve was constructed with maximum outer turning point R178+ = 17.60 A. The comparison of the long range portion of the RKR potential energy curve and the potential curve calculated from V(R)=ΣnCn/Rn is discussed. Avoided crossings around the shelf with the 3 1Σ+g state and near dissociation with the 5 1Σ+g state are also discussed.

Franck-Condon factors of the b′ 1Σu+ − X1Σg+, c3 1Πu − X1Σg+, c′4 1Σu+ − X1Σg+, c′4 1Σu+ − a 1Πg, and o3 1Πu − X1Σg+ transitions of N2

Abstract The Franck-Condon factors of the b′ 1 Σ u + − X 1 Σ g + , c 3 1 Π u − X 1 Σ g + , c′ 4 1 Σ u + − X 1 Σ g + , c′ 4 1 Σ u + − a 1 Π g , and o 3 1 Π u − X 1 Σ g + transitions of 14N2 are reported, as is a new Rydberg-Klein-Ress potential energy curve for the c′ 4 1 Σ u + state.

Observation of L uncoupling in the 5Δg1 Rydberg state of Na2

The phenomenon of electronic orbital angular momentum L uncoupled from its internuclear axis has been observed in the sodium dimer using high-resolution cw optical-optical double-resonance spectroscopy. When L uncoupling occurs, the degeneracy of Λ doubling is removed. In our experiment, the intermediate BΠu1 state of Na2 is excited from the thermally populated ground XΣg+1 state by a single-line Ar+ laser. Then, a single-mode dye laser is used to probe the Rydberg states from the intermediate state. The signals are detected by monitoring the UV fluorescence from the triplet gerade states back to the aΣu+3 state via collision energy transfer. Under our experimental resolution, the splitting of Λ doubling in the 5Δg1 state of Na2 can be measured. A total of 136 rovibronic levels with e∕f parities have been assigned to the 5Δg1 state. The Λ-splitting constants deduced from these data are q0=0.376(90)×10−4cm−1, qv=0.114(6)×10−4cm−1, and μ=0.76(33)×10−8cm−1. In general, the Λ splitting of the Δ states is cons...