Search Results - (Author, Cooperation:J. H. Chang)

2018-02-08

Institute of Physics (IOP)

1755-1307

1755-1315

Geography

Geosciences

Physics

2013-01-22

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; B-Lymphocytes/immunology/metabolism ; Bacteria/immunology ; Cells, Cultured ; Endopeptidases/deficiency/genetics/*metabolism ; Female ; Fibroblasts ; HEK293 Cells ; Homeostasis ; Humans ; Intestines/immunology ; Male ; Mice ; NF-kappa B/*metabolism ; Proteolysis ; Receptors, Cell Surface/metabolism ; TNF Receptor-Associated Factor 3/*metabolism ; *Ubiquitination

2018-12-15

The American Association for Cancer Research (AACR)

1078-0432

1557-3265

Medicine

2018-11-06

Institute of Physics (IOP)

1755-1307

1755-1315

Geography

Geosciences

Physics

1089-7550

AIP Digital Archive

Physics

The optical properties and band alignment of ZnSe/ZnMgBeSe heterostructures are investigated. Two sets of ZnSe/ZnMgBeSe multi-quantum-well structures that consist of five or three wells with different well thicknesses and 100-nm-thick ZnMgBeSe barrier layers are grown on GaAs (100) substrates by molecular beam epitaxy. Low-temperature photoluminescence spectra show dominant sharp excitonic emission whose peak position systematically shifts to the higher energy side with decreasing the well thickness. Photoluminescence excitation spectra show optical transitions between excited quantum levels in addition to the ground levels. The standard analysis based on the effective-mass approximation gives the valence band offset of ΔEυ=(0.4±0.1)ΔEg. This is consistent with calculated values based on Harrison's linear combination of atomic orbitals theory. © 2002 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Heteroepitaxial growth of InP on ZnSe-coated Si substrates by low-pressure metalorganic vapor phase epitaxy is reported for the first time. Single-crystal InP epilayers with specular surfaces can be obtained. The ZnSe buffer layer, which is evaporated onto the Si substrate in another furnace, is effective in reducing the magnitude of strain in the InP layer. The best room-temperature electron mobility of the undoped InP epilayer can reach 3100 cm2 /(V s) with a carrier concentration of 1.5×1015 cm−3 . It was found that the InP electron mobility is critically dependent on the ZnSe buffer-layer thickness. The efficient photoluminescence compared with that of InP homoepitaxy indicates that the InP heteroepilayer is of high optical quality.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

ZnSe epitaxial layers were successfully grown on (111) Si substrates by low-pressure metalorganic chemical vapor deposition. It is not necessary that the reactant inlet tubes project to near the substrates. From x-ray and scanning electron microscopy examinations, single-crystalline ZnSe epilayers with mirrorlike surfaces can be obtained. The carrier concentration profile shows that the carrier distribution in the epilayer is very uniform. The electron mobility of the epilayer at room temperature is 280 cm2 /V s. The efficient 77-K photoluminescence indicates that the ZnSe epilayers are of good quality.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

CeO2 layers epitaxially grown on (100) silicon substrates by electron-beam evaporation were investigated and proved to have (110) orientation. X-ray diffraction measurements showed the CeO2 layers consist of more than 98% volume fraction of the (110) component. Cross-sectional high-resolution transmission electron microscopy and selected-area electron diffraction clearly verified the above configuration of crystallographic orientations and that the 〈100〉 direction in the CeO2(110) plane is parallel with the 〈110〉 direction in the Si(100) plane. The cross-sectional lattice image clarified the existence of a ∼60-A(ring)-thick intermediate amorphous layer between the CeO2 layer and the silicon substrate. Moreover, the high density of defects such as dislocations and low-angle boundaries that exist in the vicinity of the interface agree well with Rutherford backscattering and channeling measurements.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The structural and optical properties of high-quality homoepitaxial ZnTe films are investigated. A substrate surface treatment using diluted HF solution plays a key role in growing device-quality ZnTe layers. X-ray diffraction analysis of ZnTe epilayers based on the crystal-truncation-rod method suggests that a homoepitaxial ZnTe film grown on a HF-treated substrate can be regarded as an ideal truncated crystal without an interfacial layer, while a ZnTe layer grown on a substrate without HF treatment suggests the presence of an interfacial layer which may lead to degraded crystallinity of ZnTe overlayers. The crystal quality of the homoepitaxial ZnTe layers with HF treatments are characterized by an extremely narrow x-ray diffraction linewidth of 15.6 arcsec and dominant very sharp excitonic emission lines with dramatically reduced deep-level emission intensity in the photoluminescence (PL) spectrum. Three bound excitonic emission lines at neutral acceptors are observed in the PL from the high-quality ZnTe homoepitaxial layers in addition to the free-exciton emission line, suggesting the presence of three different kinds of residual acceptor impurities. © 2000 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The composition dependence of the energy gap (Eg) of Zn1−x−yMgxBeySe quaternary alloys grown by molecular-beam epitaxy was investigated. The energy gap of Zn1−x−yMgxBeySe can be controlled in a range of 2.7 eV〈Eg〈3 eV under nearly lattice-matching conditions to GaAs(001). The phenomenological formula for the energy gap of ZnMgBeSe quarterly is obtained using the bowing parameters theoretically or experimentally estimated for the ternary compounds. These results show that nonlinear behavior was observed on the composition dependence of the energy gap as the Be and Mg compositions increased. © 2001 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We have achieved low-threshold optically pumped lasing at 444 nm at room temperature with high characteristic temperature (T0) from ZnSe/ZnMgBeSe single-quantum-well structures. The threshold intensity is as low as 15 kW cm−2, while T0 value is as high as 166 K. Lasing is observed up to 473 K. Lasing wavelength of 444 nm at room temperature is the shortest wavelength ever achieved in ZnSe-based laser diode structures. The laser structure includes a single ZnMgBeSe/ZnSe/ZnMgBeSe quantum well with a ZnSe well thickness of 4 nm. The (004) x-ray diffraction rocking curve of the ZnMgBeSe quaternary cladding layers shows a sharp diffraction peak with a full width at half maximum of 21 arcsec which is in contrast to that from a ZnMgSSe cladding layer showing much broader multiple peaks. The observed lasing features are partly ascribed to high crystal quality of the ZnMgBeSe layers and type-I band alignment, as has been supported by photoluminescence in addition to x-ray diffraction measurements. © 1999 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

N-type ZnTe layers with high electron concentration are grown by molecular-beam epitaxy using aluminum as the donor species. The ZnTe:Al layers show a high structural quality with a narrow x-ray diffraction linewidth (24 arcsec) and a high carrier concentration up to n=4×1018 cm−3 with low resistivity (ρ=0.017 Ω cm). The dependence of the electron mobility on the carrier concentration suggests that the dominant scattering mechanisms in the ZnTe:Al layers are ionized impurity scattering and polar optical phonon scattering. The photoluminescence spectrum of moderately doped ZnTe layers shows strong Al–donor-related bound exciton lines: I2 (2.378 eV) and donor–acceptor pair emission (zero phonon energy=2.324 eV) with a weak deep-level emission (2.19 eV). Highly Al-doped layers show an increase in the deep-level emission intensity and a decrease in carrier mobility, which are interpreted in terms of the increase in the carrier compensation. © 2001 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

A ZnCdTe/ZnTe/ZnMgSeTe quantum-well (QW) structure lattice matched to ZnTe is proposed for the light-emitting devices in the pure-green wavelength region. Thin ZnTe layers are inserted in between the ZnCdTe QW layer and ZnMgSeTe cladding layers, which improve the quality of the QW structure as demonstrated by its narrow photoluminescence line width (6.5 meV at 10 K). Optically pumped lasing at 552 nm at room temperature with a threshold optical power of 215 kW cm−2 is achieved. The present results clearly show the feasibility of ZnTe-based QW structures for the application to light-emitting devices in the pure-green wavelength region. © 2001 American Institute of Physics.

Electronic Resource

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Process Engineering, Biotechnology, Nutrition Technology

: Use of several lipids as an alternative to cholesterol to prepare stable liposomes was tried. Liposome prepared at 1/0.25 lecithin/stearic acid ratio exhibited better (55%) encapsulation efficiency (EE) of bovine serum albumin (BSA) than that (41%) prepared at 1/0.25 lecithin/cholesterol ratio. Liposomes showed the minimal released percentage of encapsulated BSA at pH 6. Storage at −20 °C caused serious damage to liposomes. Addition of α–tocopherol was effective in stabilizing liposomes. Liposomes, incorporated with α–amylase, prepared at 1/0.25 lecithin/cholesterol or stearic acid ratio were effective in protecting enzyme against acid (pH 2.8) and pepsin (15 mg/mL). Use of stearic acid, instead of cholesterol, would be feasible in preparing stable liposomes.

Electronic Resource

1089-7666

AIP Digital Archive

Physics

This paper briefly surveys the three compact, high-current accelerators that are presently under development in the United States in support of a national program. In addition, it reports recent experimental results from the Naval Research Laboratory (NRL) modified betatron [Phys. Rev. Lett. 64, 2374 (1990)] with emphasis on the electron-cyclotron resonance that presently limits the energy of the beam to approximately 18 MeV. Finally, it briefly addresses selective existing and prospective applications of accelerators.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

We report on the growth and characterization of beryllium–chalcogenide layers prepared on GaAs (100) by molecular beam epitaxy. Be- and Te-terminated BeTe surfaces show (4×1) and (2×1) reconstructions, respectively. The stability of each surface is investigated by reflection high energy electron diffraction as a function of substrate temperature. The dependence of growth rate of BeTe on growth temperature and Be cell temperature is investigated. The best full width at half maximum (FWHM) of a (400) x-ray rocking curve of BeTe is 78 arcsec. The dependence of the ZnBeSe energy gap on Be composition is obtained by four-crystal x-ray diffraction (XRD) and low temperature photoluminescence measurements. The energy gap of Zn1−xBexSe varies as Eg=0.0107x+2.790 (eV) for small Be composition (x〈0.25) at 77 K. Lattice-matched ZnBeSe (Eg=2.82 eV) and ZnMgBeSe (Eg=2.975 eV) layers show narrower XRD peaks, the FWHM values of which are 64 and 21 arcsec, respectively. The variation of FWHM of x-ray rocking curve due to lattice misfit is investigated for ZnMgBeSe quaternaries with various lattice misfits extending from compressive to tensile strain. The FWHM value under compressive strain increases more steeply with lattice misfit than that under tensile strain. © 1999 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

ZnSe is a semiconductor with a direct band gap of 2.68 eV at room temperature, which makes it one of the most important materials for blue electroluminescent devices and short wavelength laser diodes. In this communication, heteroepitaxial growth of ZnSe on a GaAs/Si substrate by low-pressure organometallic chemical vapor deposition is reported. The ZnSe/GaAs/Si epilayer exhibits a uniform surface morphology. Strong photoluminescence near-band-edge emission was observed. The thickness of the GaAs buffer layer seems to be an important factor in the energy shift of the photoluminescence peak.

Electronic Resource

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Process Engineering, Biotechnology, Nutrition Technology

: Lactoferrin (LF) in colostral whey was isolated by anti-LF immunoglobulin in yolk (IgY)-Sepharose 4B immunoaffinity chromatography, and parameters such as binding capacity (qm) and dissociation constant (Kd, × 10−6 M) of this immunoaffinity gel for LF were discussed. Purification folds for colostral whey I (from colostrum collected within 6 d of postpartum) and colostral whey II (from colostrum collected within 1 d of postpartum) by anti-LF IgY-immunoaffinity chromatography were 135.80 and 103.60, respectively. The recovery for LF in the same colostral whey sample by anti-LF IgY-immunoaffinity chromatography was 82 to 99 %. qm of anti-LF IgY-immunoaffinity gel for LF in colostral whey I and whey II were 0.372 and 0.272 mg LF/mL wet gel, respectively. Kd of anti-LF IgY-immunoaffinity gel for LF in colostral whey I was 1.594 × 10−6 M and II was 1.587 × 10−6 M.

Electronic Resource

0014-4827

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Medicine

Electronic Resource

1432-0630

PACS: 78.20.Wc; 78.45.+h; 78.40.Fy

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Physics

Electronic Resource