Optical Characterization of ZnMnO Thin Films on c-Al2O3

H. J. LIN,D. Y. Lin,J. S. Wu,W. C. CHOU,C. S. YANG,J. S. WANG,W. H. Lo 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.1

Various optical measurement technologies have ben used to characterize ZnMnO thin filmswith different Mn compositions grown by molecular beam epitaxy(MBE) on c-Al2O3 substrates. Thelat- tice constant and the crystalization quality have ben evaluated by using X-ray diraction (XRD). Photoluminescence (PL) has ben used to reveal the neutral-donor-bound exciton (D0X) and to checkthelm'squality. Defect-relatedabsorptionsignatures,inadditiontonear-band-edgeabsorp- tion, due to the zinc vacancy and the donor-aceptor pair (DAP) have ben found in the surface photovoltagespectra(SPS).Freexcitonictransitionsandtheirphonon-asistedreplicashaveben observed in the re ectance spectra. Our experimental results not only unveil specic optical tran- sitionenergies but also indicate arapid materiald deterioration whenMn incorporation goes beyond a certain amount to cause manganese segregation. Various optical measurement technologies have ben used to characterize ZnMnO thin filmswith different Mn compositions grown by molecular beam epitaxy(MBE) on c-Al2O3 substrates. Thelat- tice constant and the crystalization quality have ben evaluated by using X-ray diraction (XRD). Photoluminescence (PL) has ben used to reveal the neutral-donor-bound exciton (D0X) and to checkthelm'squality. Defect-relatedabsorptionsignatures,inadditiontonear-band-edgeabsorp- tion, due to the zinc vacancy and the donor-aceptor pair (DAP) have ben found in the surface photovoltagespectra(SPS).Freexcitonictransitionsandtheirphonon-asistedreplicashaveben observed in the re ectance spectra. Our experimental results not only unveil specic optical tran- sitionenergies but also indicate arapid materiald deterioration whenMn incorporation goes beyond a certain amount to cause manganese segregation.

Applications of Laser-Fabricated Plasma Structures in Laser-Wakefield Accelerators, X-ray Lasers and Plasma Nonlinear Optics

C.T. Hsieh,M.W. Lin,C.L. Chang,Y.C. Ho,S.Y. Chen,J. Wang,M.C. Chou,J.Y. Lin,C.H. Pai,P.H. Lin,L.C. Tai,S.H. Chen,G.Y. Tsaur,C.C. Kuo,T.Y. Chien 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.6

A general method for fabricating transient plasma structures with high-intensity laser pulses is developed to gain fine control over laser-plasma interactions. These structures have been used as programmable photonic devices in the development of laser-wakefield accelerators, soft X-ray lasers and plasma nonlinear optics driven by multi-terawatt laser pulses. Plasma ramps are used to control electron injection in laser-wakefield accelerators, plasma waveguides are used to enhance the efficiency of soft X-ray lasers by orders of magnitude and periodic plasma structures are used to achieve quasi-phase matching in relativistic harmonic generation. By scanning the interaction length with the same plasma-fabrication method, tomographic measurements are carried out to resolve the injection/acceleration process in laser-wakefield accelerators and amplification processes in X-ray lasers and relativistic harmonic generation. A theoretical analysis and a computer simulation are also carried out to provide insightful pictures of these processes. These research works show that by controlling plasma structures with optical fabrication methods, laser-plasma interaction can be engineered to expand and enrich the frontier of high-field physics.

Carrier Dynamics in Self-Assembled CdTe Stranski-Krastanow Quantum Dots Grown on ZnSe by Molecular Beam Epitaxy

C. S. Yang,K. F. Chien,J. Y. Lai,C. W. Luo,W. C. Chou,Y. T. Shih,J. S. Wang,S. R. Jian 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

Self-assembled CdTe/ZnSe Stranski-Krastanow quantum-dot (QD) structures, which have a CdSe-like precursor-layer (PCL) between CdTe quantum dots and ZnSe matrix, were grown by molecular beam epitaxy. The carrier dynamics of the structures was studied by photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurements. The temperature-dependent PL spectra revealed that there is a carrier transformation from small dots to larger dots via the precursor layer. Temperature-dependent PL measurements verify the existence of the QD excited excitonic state in 5.0 mono-layer (ML) coverage. In 0.6 ML coverage, the TRPL spectra exhibited a double-exponential decay process, as the detection energy at PCL emission energy. The faster decay time is corresponded to the carrier lifetime in PCL, the slower decay time exhibits the carrier in small QD. However, in 5.0 ML coverage, a faster and slower decay time represents the carrier lifetime in QD excited state for larger QD and the carrier lifetime in QD ground state for smaller QD.

Structure and magnetic properties of [Co / Pt] single crystal and bicrystal superlattice

C. C. Yu,Y. C. Chu,S. C. Chou,Y. Liou,W. C. Cheng,Y. D. Yao 한국자기학회 2003 한국자기학회 학술연구발표회 논문개요집 Vol.13 No.2

Bilayer thickness effect on the magnetic properties of [Fe / Pt]n films

S. C. Chou,C. C. Yu,Y. D. Yao,Y. Liou 한국자기학회 2003 한국자기학회 학술연구발표회 논문개요집 Vol.13 No.2

Glucose and Its Role in Generating Reactive Oxygen Species Required for Mouse Sperm Fertilizing Ability

Lin, S.C.,Chen, M.C.,Huang, A.J.,Salem, B.,Li, K.C.,Chou, K. Asian Australasian Association of Animal Productio 2000 Animal Bioscience Vol.13 No.6

Effects of xanthine (X), xanthine oxidase (XO), and catalase (C), $H_2O_2$, and carbohydrates on sperm capacitation, acrosome reaction, and fertilizing ability in vitro were examined. Glucose alone, but not fructose, supported the maximum rate of sperm capacitation and acrosome reaction. However, in the combination of X, XO, and C (XXOC) or $H_2O_2$, fructose alone also supported maximum capacitation, acrosome reaction, and fertilization. Either insufficient or excessive amounts of $H_2O_2$ decreased sperm capacitation and the acrosome reaction. In order to understand how glucose generates $H_2O_2$ or other reactive oxygen species in sperm cells, 6-aminonicotinamide, an inhibitor of the pentose-phosphate pathway (PPP), and apocynin, an inhibitor of NADPH oxidase, were added to sperm suspensions in glucose-containing medium. Results appeared that sperm capacitation, acrosome reaction, and fertilization were consequently inhibited by either one of these compounds. These inhibitory effects were nullified by addition of XXOC. These results support the hypothesis that glucose, in addition to being a substrate for glycolysis, facilitates sperm capacitation and the acrosome reaction by generating reactive oxygen species through G-6-P dehydrogenase and NADPH oxidase.

Synchronized Bursting Induced by Network Connectivity in Cortical Neuronal Cultures

L.C. Jia,P.-Y. Lai,C. K. Chan,C.H. Chang,C.R. Han,M.T. Tsai,Y.S. Chou 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.1I

Synchronization of cortical neural cultures is studied as a function of the effective network connectivity in the phenomenon of synchronized firing (SF). The synchronized bursting frequency (during SF) of the network is found to be much slower than the characteristic time scale of a neuron and increases with the network connectivity. Using fluorescence imaging techniques, we found that SF occurs only when the incubation time is longer than some critical age tc and the synchronized bursting frequency f increases with time as f = fc + fo log( t tc ). Furthermore, tc is found to scale with the cell plating density as tc 1 p . Based on the result of photolysis of neurons, the synchronized bursting frequency is shown to be related to the network connectivity, hence, the growth behavior can be inferred from the measured SF frequencies. We further build a network growth model with the characteristics of an early stage active growth followed by a late-stage retarded growth, which can account for the experimental data quantitatively. Electrophysiological measurements using double-patch techniques reveal that even though the bursting frequencies are synchronized, the intra-burst spikes are not. We also present a mean-field model of the neural network that enables the neuron firing to be inhibited and generates inter-spike intervals with long time scales resulting in bursting.

Surgical Oocyte Retrieval and the Developmental Potential of the Oocytes Derived from Prepubertal Calves

Yeh, S.P.,Ju, J.C.,Tseng, J.K.,Chou, P.C.,Chen, C.H.,Chih, T.,Fan, Y.K. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.2

The objectives of this study were to investigate the ovarian responsiveness of juvenile calves to exogenous gonadotropin treatments and to establish the oocyte retrieval technique for prepubertal heifers. Three 78-day-old calves were treated with 4 doses (40, 30, 30 and 30 mg) of FSH (Folltropin V) at 12 h interval up to 229 day-old. Surgical oocyte retrieval was performed 24 h after the last injection of FSH. Calves with good ovarian responses to FSH treatment had an average ovarian size of $5{\times}3$ cm compared to $3{\times}2$ cm in the less-responsive animals. Large variations were observed in the number of total follicles ($51{\pm}45$), aspirated follicles ($39{\pm}36$), oocytes recovered ($23{\pm}25$) and usable oocytes recovered ($11{\pm}19$) during 78 to 229 day-old. Oocytes derived from prepubertal calves had significantly lower maturation rate than those from cows (34 vs. 100%, p<0.05). Mean diameters of calf oocytes ($144{\pm}1{\mu}m$) and ooplasm ($110{\pm}1 {\mu}m$) were significantly lower than those of cows ($149{\pm}1$ and $25{\pm}1{\mu}m$, respectively). The diameter of the ooplasm also increased significantly after in vitro maturation (IVM) ($108{\pm}1$ vs. $112{\pm}1{\mu}m$). However, further studies are required to optimize the IVP system for the oocytes derived from prepubertal heifers.

Ni removal from aqueous solutions by chemical reduction: Impact of pH and pe in the presence of citrate

Li, C.W.,Yu, J.H.,Liang, Y.M.,Chou, Y.H.,Park, H.J.,Choo, K.H.,Chen, S.S. Elsevier Scientific Pub. Co 2016 Journal of hazardous materials Vol.320 No.-

The chemical precipitation of Ni ions from industrial wastewater at alkaline pH values creates waste chemical sludge (e.g., Ni(OH)<SUB>2</SUB>). We herein focused on Ni removal via chemical reduction using dithionite, by converting Ni(II) to its elemental or other valuable forms. Without the presence of a chelator (e.g., citrate), the nickel reduction efficiency increased with increasing dithionite:Ni molar ratio, reaching @?99% at ratios above 3:1. The effect of pH on Ni reduction was in agreement with the standard redox potentials (pe<SUP>0</SUP>) of dithionite, which became more negative with an increase in pH leading to greater Ni reduction efficiencies. With the formation of Ni-citrate chelates, however, the Ni reduction deteriorated. Elevated pH and temperature improved nickel reduction, due to the greater reducing power of dithionite. The optimal pH value for Ni(II) reduction was found to be @?8. Injecting Cu seed particles enhanced the rate and amount of Ni reduced. NiS and Ni<SUB>3</SUB>S<SUB>2</SUB> were identified in the crystal of the resulting solids by X-ray crystallography, and the presence of elemental Ni was explained by X-ray photoelectron spectroscopy. The chemical reduction of actual printed circuit board wastewater with the dithionite:Ni(II) molar ratio dose of 12:1 retrieved @?99% nickel after 30-min reaction at 40<SUP>o</SUP>C.

이온화칼숨 측정의 비교 연구

이승관 ( S K Lee ),이창규 ( C K Lee ),류정록 ( J R Ryu ),검석수 ( S Su Kim ),김상섭 ( S S Kim ),김창영 ( J Y Kim ),장철수 ( Chou I Soo Chang ) 대한임상검사과학회 1993 대한임상검사과학회지(KJCLS) Vol.25 No.1

Calcium exists in serum in three forms, as the free ion and as complexes with proteins and with smaller molecules; of these, the ionized species is the one that in physiologically active. For this reason some investigators tried to find the most convenient method for estimating calcium IOns. In this study, we compared three measurements (Zeisler, Mario and Hanna method) for inoized calcium to our Nova 7 method. Patient comparison results for ISE(x) compared to the other three methods. (y) are : Zeisler=0.579x+0.944, r=0.394, n=50;Mario =0.435x+l.469, r=0.216, n=50;Hanna=O. 905x+0.749, r=0.479, n=50. In conclusion, all performance characteristics of the nomogram method evaluated in this study were found to be incompatible to the Nova 7 method for serum ionized calcium analySIS.