Search Results - (Author, Cooperation:C. Cho)

2018-05-04

BMJ Publishing

2044-6055

Medicine

Health informatics, Open access, Health informatics

2018-06-16

Nature Publishing Group (NPG)

2041-1723

Biology

Chemistry and Pharmacology

Natural Sciences in General

Physics

2011-02-19

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Adenosine Triphosphate/metabolism ; Allosteric Regulation ; Amino Acid Sequence ; Binding Sites ; Crystallography, X-Ray ; Cytoplasmic Dyneins/*chemistry/*metabolism ; Methionine/chemistry ; Microtubules/*metabolism ; Models, Molecular ; Molecular Sequence Data ; Protein Conformation ; Protein Folding ; Protein Multimerization ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Recombinant Fusion Proteins/chemistry ; Saccharomyces cerevisiae Proteins/*chemistry/*metabolism

2018-07-06

The American Society for Pharmacology and Experimental Therapeutics (ASPET)

0090-9556

1521-009X

Chemistry and Pharmacology

Medicine

2018-07-10

The American Association of Immunologists (AAI)

0022-1767

1550-6606

Medicine

2018-04-13

American Physical Society (APS)

1098-0121

1095-3795

Physics

Superfluidity and superconductivity

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The dynamics of the UV photochemistry of HBr on LiF(001) has been studied by angle-resolved time-of-flight mass spectrometry in ultra-high vacuum. Single-photon photodissociation of adsorbed HBr at 193 nm resulted in photofragment translational energy distributions that differed from those produced in the gas-phase photolysis. Angular distributions of the fast H-atom photofragments peaked at 55±5° to the surface normal, consistent with a preferentially oriented adsorbate geometry. The angular distribution of atomic H obtained from photodissociation of HBr(ad) using polarized light indicated that a substantial fraction of the H atoms collided with the surface before leaving it. Two types of photoreactions in the adsorbed state were observed. Molecular hydrogen was formed in the photoinitiated abstraction reaction, H+HBr(ad)→H2(g)+Br, and its markedly non-Boltzmann translational energy distribution was found to have less energy than would be consistent with gas-phase experiments (performed elsewhere). Photoproducts from the bimolecular reaction 2HX(ad)→H2+X2, X=Cl, Br were also observed in the present study. This photoreaction, which did not depend on prior photodissociation of HX(ad), is thought to proceed through electronic excitation of an HX dimer in the adsorbed state.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

This article presents a novel electric motor/pump system that combines an axial field, permanent magnet motor with a centrifugal pump. This system, unique because the motor permanent magnet rotor and pump impeller vanes are a single unit, provides a compact, reliable, low-noise, and high-power density electrically driven centrifugal pump suitable for underwater applications in which minimizing noise, vibration, and volume are major design objectives. Performance tradeoffs for the electromagnetic analysis were made by three-dimensional finite element analysis models in conjunction with a lumped parameter magnetic circuit model. © 1996 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Molybdenum metal deposition from the decomposition of Mo(CO)6 adsorbed on Si(100), Mo, and Cu surfaces was studied by x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, thermal desorption spectroscopy, and low-energy electron diffraction. Pyrolytic, photolytic, and electron-induced Mo(CO)6 decomposition were observed and indicated different dissociation mechanisms. Thermally decomposed Mo(CO)6 was found to leave metallic Mo in the presence of C and O. Electron-induced decomposition resulted in the formation of molybdenum carbide on the surfaces. Ultraviolet (UV) irradiation of adsorbed Mo(CO)6 induced new peaks in XPS and TDS spectra, suggesting the formation of an unsaturated molybdenum carbonyl adsorbate. Mo(CO)6 was found to form a multilayer on these surfaces at low temperatures, and desorb with zero-order kinetics. Although both adsorbate desorption and decomposition took place when the samples were heated, desorption was the dominant reaction path. UV irradiation of gaseous and coadsorbed Mo(CO)6 and O2 was also investigated. UV irradiation of the gas-phase mixture leads to MoO2 and MoO3 deposition; however, UV irradiation of coadsorbed Mo(CO)6 and O2 resulted in unsaturated molybdenum carbonyl. The effects of annealing and Ar+ bombardment on the Mo-deposited Si(100) surface are also reported.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A modified Hartshorn inductance bridge is used to follow changes in the magnetization of superparamagnetic samples in order to determine their average temperature. The thermometry is performed in the temperature range of 475–525 K. During routine experiments, the rms noise voltage in the bridge is approximately 300 nV when the primary coil is excited by a 200 mA rms current at a frequency of 47 Hz. This corresponds to a signal-to-noise ratio of 3000 and a temperature sensitivity of 0.015 K for typical samples studied.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We have studied the visible photoluminescence (PL) and microstructure of amorphous Si (a-Si) after annealing and etching. The a-Si layers were grown on (100)Si substrates and partially crystallized by annealing between 550–1150 °C. Porous Si layers (PSLs) were then produced by etching in HF-HNO3. While no visible PL was observed from unannealed and etched a-Si, visible PL was detected after annealing and etching. The observation of visible PL after etching coincided with the observation of Si microcrystallites in the annealed layer. The results suggest that an initial crystalline structure is important for fabricating luminescent PSLs.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Despite their large lattice mismatch (∼25%), epitaxial CaF2 films have been grown on single crystal Al(111) on Si(111) by low temperature molecular beam epitaxy. X-ray diffraction shows that the orientations of the CaF2 are the same as those of the Al films, whether the orientations of the Al are the same rotated 180° or with respect to the underlying Si substrate. Furthermore, our successful fabrication of an epitaxial Al/CaF2/Al/Si(111) structure suggests that Al can be a useful conductor material in three-dimensional device integration.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Using a thin predeposited B layer prior to the epitaxial growth of Ge on CaF2, we have obtained significantly improved Ge crystalline quality and surface morphology for Ge/CaF2/Si(111) and Ge/CaF2/Si(100) structures. Although B acts as a surfactant in suppressing island formation, it does not migrate to the growth front during Ge growth, which was widely observed in the surfactant-assisted epitaxial growth of Ge on Si. The B predeposit also prevents Ca from migrating to the Ge surface, and promotes A-type epitaxy of Ge(111) when Si(111) substrates are used.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Nd3+ doped CaF2 films have been grown epitaxially on Si(111) and Al(111)/Si(111) using CaF2 and NdF3 evaporation. Photoluminescence spectra from these samples show high intensity and narrow emission linewidth even when the thickness of the CaF2:Nd films is reduced to 0.2 μm. The 10 457 A(ring) emission line is not quenched until the Nd concentration exceeds 3.8 wt.%. Moreover, while similar spectra are observed, the photoluminescence intensity from the CaF2:Nd films grown on Al/Si(111) is significantly higher than from the CaF2:Nd on Si(111).

Electronic Resource

1077-3118

AIP Digital Archive

Physics

While epitaxial CaF2 films grown on Si(111) at temperatures above 550 °C exhibited flat capacitance-voltage (C-V) curves, suggesting a pinned CaF2/Si(111) interface, we have observed unpinned C-V curves from as-deposited epitaxial CaF2 grown at 300 °C. Our results demonstrate that C-V characteristics of CaF2/Si(111) are determined by the thermal history, rather than the crystalline quality, of the CaF2 film. Correlations among CaF2/Si interface state density, thermal stress, and atomic bonding at the interface are discussed.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Photoexcitation of silicon during low-fluence implantation with MeV Si and Ge ions is observed to suppress vacancy-type point-defect formation, as determined by in situ deep-level transient spectroscopy. The A-center formation after low-temperature implantation is extended over a wide temperature interval indicating that electrically inactive clusters, which emit vacancies during annealing, are formed in the end-of-range region during implantation at 85 K. The number of vacancies stored in these clusters is influenced by low-temperature in situ photoexcitation. © 1999 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

In situ deep-level transient spectroscopy measurements have been carried out on p-type silicon following MeV He, Si, and Ge ion implantation at 85 K. Deep levels corresponding to intrinsic and impurity-related point defects are only detected after annealing at temperatures above 200 K. In addition to divacancies, interstitial carbon, and a carbon–oxygen complex, the formation of another defect, denoted as K2, has been observed during annealing at 200–230 K in epitaxial wafers, and at 200–300 K in Czochralski grown material. The energy level of the K2 defect is located 0.36 eV above the valence band, which is very close to a previously observed level of the carbon–oxygen pair. The relative concentration of this defect is ∼10 times higher in samples implanted with Ge than in those implanted with He. Due to its formation temperature, equal concentration in epitaxial and Czochralski grown wafers, and absence in n-type samples, the K2 trap has been tentatively identified as a vacancy-related complex which probably contains boron. © 1999 American Institute of Physics.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

This study was performed to evaluate the effects of cryoanalgesia combined with thoracic epidural analgesia on pain and respiratory complications in patients undergoing thoracotomy. Ninety patients were prospectively randomised to epidural analgesia alone (n = 45) or epidural analgesia and cryoanalgesia combined (n = 45). We monitored the use of rescue pain medication and changes in forced vital capacity and forced expired volume in 1 s, and recorded pain and opioid-related side-effects during the immediate postoperative period. The incidence of post-thoracotomy pain and numbness were also assessed up to the sixth month after surgery. Cryoanalgesia combined with thoracic epidural analgesia was associated with earlier recovery in pulmonary function, less pain during movement and a lower daily requirement for rescue analgesia one week after surgery. However, the combination of cryoanalgesia and epidural analgesia failed to decrease the incidence of long-term pain and numbness. In view of its associated long-term morbidity, cryoanalgesia combined with thoracic epidural analgesia is not recommended for patients undergoing thoracotomy.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The steep non-Arrhenius temperature dependence at low temperatures of the shear viscosity of water and its backwards-sounding increased fluidity under pressure for temperatures below 33 °C are two of the anomalies of this liquid that have been known for a very long time. The purpose of the present paper is to show how these two important characteristics of water emerge quantitatively from an explicit two-state outer-neighbor mixture model that we have used to explain many other properties of this substance. It will be shown here that both of these viscosity anomalies are directly related to the steep variations with temperature and pressure of the fractional compositions of ice-Ih-type bonding and ice-II-type bonding in the two-state mixture. This compositional dependence has already been obtained in earlier work from the variations of the density and the isothermal compressibility of water with temperature. The viscosity analysis presented here thus helps to unify further all the properties of this liquid under a single, very simple structural characteristic. © 1999 American Institute of Physics.

Electronic Resource