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  • 1
    Electronic Resource
    Electronic Resource
    A study of internal absorption in Zn(Cd)Se/ZnMgSSe semiconductor lasers (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 2621-2626 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Based on two different experiments and an optical field calculation, we show that the free-carrier absorption αfc in Zn(Cd)Se/ZnMgSSe semiconductor lasers is about 4 cm−1 and that it is smaller than that of GaAs/AlGaAs semiconductor lasers. We have measured the dependence of the L-I characteristics on the cavity length of double heterostructure (DH) lasers under photopumped operation and of single quantum well-separate confinement heterostructure (SQW-SCH) lasers under current-injected operation. For the DH laser, the total absorption coefficient αi and β×J0 product (β is a gain constant, and J0 is the nominal current density that makes the gain equal to zero) are estimated to be 4.2 cm−1 and 8.6×10 cm−1, respectively. For the SQW-SCH laser, αi, β, and J0 are estimated to be 21 cm−1, 4.23×10−3 cm×μm/A, and 1.9×10−3 A/(cm2×μm), respectively. By calculating the optical fields of these lasers, we have estimated that the absorption in a GaAs substrate is 16.53 cm−1 in the SQW-SCH laser and that it is negligible in the DH laser. We have shown that the large loss in the SQW-SCH laser is caused by both αfc and the absorption in the substrate and that αi in the DH laser is caused only by free carrier absorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357558
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  • 2
    Electronic Resource
    Electronic Resource
    Pattern dependence in selective epitaxial Si1−xGex growth using reduced-pressure chemical vapor deposition (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 2716-2719 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Pattern dependence of the growth rate and Ge content in selective epitaxial Si1−xGex growth using reduced-pressure chemical vapor deposition has been examined for the SiH2Cl2-GeH4-H2 system. Contrary to selective epitaxial Si growth where pattern dependence diminishes at low growth temperatures, the growth rate of selectively grown Si1−xGex layers depends on the ratio of the exposed Si area to the oxide-covered area on a wafer, at temperatures as low as 600 °C. The Ge content in the layers also depends on the ratio, and the dependence is greater at higher temperatures. Adding HCl to the gas phase decreases the pattern dependence of both growth rate and Ge content. Although, in terms of the growth rate, an optimum HCl flow rate for pattern-insensitive growth exists, the Ge content in the layers is always higher for the wafer with a smaller exposed area. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360068
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  • 3
    Electronic Resource
    Electronic Resource
    Time-resolved optical waveguide study of the reorientation in a nematic liquid crystal under applied electric field (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 1135-1142 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The reorientation behavior of nematic liquid crystal molecules induced by an electric pulsed field was investigated by means of time-resolved optical waveguide spectroscopy (TROWS) which was developed to observe transient changes in dielectric constants and to measure the thickness of a thin dielectric medium. Time evolution of the waveguide mode patterns was successfully obtained by using TROWS, which records the reflectivity as both functions of the incident angle of laser light and the time from switching-on or -off of the external electric field. The transient dielectric tensor profile in the 4′-pentyl-4-cyanobiphenyl (5CB) layer both after switching-on and -off of the electric field could be precisely determined in a three-dimensional coordinate system by using Deuling's theory which treats the orientational deformation induced by an external electric field. Theoretical analysis of TROWS data clearly indicated that half of the 5CB molecules rotate clockwise in the plane defined by the rubbing direction and the substrate normal, and the other half rotates counter-clockwise in the same plane. The counter rotation compensates the effect of birefringence observed in the direction parallel and perpendicular to the rubbing direction and the reorientation kinetics could be well described by the Ericksen–Leslie equation. Relaxation behavior from homeotropic to planar orientation could be treated as an orientation diffusion process by applying a Gaussian distribution function to the maximum tilting angle at the middle of the cell. We report the usefulness of TROWS which provided more detailed information about the dynamics of the 5CB molecules. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363859
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  • 4
    Electronic Resource
    Electronic Resource
    A new gas purifier for ArF excimer lasers (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 658-661 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have developed a new gas purifier for ArF excimer lasers that can remove all the impurities from degraded ArF excimer laser gas. We found that cooled activated charcoal at temperatures below −50 °C effectively removes CF4, which is the preponderant impurity generated in ArF excimer laser gas mixtures. We also demonstrated that the new gas purifier can regenerate the ArF excimer laser gas up to its initial purity level after about 1×109 shots of operation. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146837
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  • 5
    Electronic Resource
    Electronic Resource
    Read efficiency measurements for thin film heads (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 3955-3957 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Read efficiency values for thin film heads have been measured using a readback voltage integration method. Read efficiency η can be expressed by η=Φh/Φm, where Φh is the magnetic flux linking coil turns in the head and Φm is the magnetic flux emanating from the recorded region in the media. Readback voltages were integrated digitally and converted into integrated waveforms, which correspond to Φh. High read efficiency values, 87 and 91%, were measured for a thin film head and a MnZn ferrite head, respectively, using 8-in. CoNiP plated disks at below 0.19 μm flying height and at below 5-kFRPI recording densities. Integrated waveforms for thin film heads had square shapes with overshoots and undershoots. The peak values for these overshoots and undershoots reflect pole piece configurations and/or their magnetic properties. This readback voltage integration method is efficient for evaluating thin film head performance experimentally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.334875
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  • 6
    Electronic Resource
    Electronic Resource
    Kinetics of epitaxial Si1−xGex growth using SiH2Cl2–GeH4–H2 mixture in reduced-pressure chemical vapor deposition (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 1098-1100 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The dependences of the Ge/Si ratio in epitaxial Si1−xGex layers grown using a SiH2Cl2–GeH4–H2 mixture by reduced-pressure chemical vapor deposition on the flow rate ratio of GeH4/SiH2Cl2 and on the total flow rate have been examined in the temperature range from 480 to 600 °C. As previously reported, the Ge/Si ratio does not increase linearly with the flow rate ratio; instead, the rate of increase decreases at high flow rate ratios. Additionally, it increases with increasing total flow rate when the ratio of GeH4/SiH2Cl2 is fixed. It is found that these flow rate dependences are well accounted for by assuming that the reaction order for SiH2Cl2 adsorption is twice as large as that for GeH4 adsorption. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117070
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  • 7
    Electronic Resource
    Electronic Resource
    Time-resolved optical waveguide spectroscopy: Application to a study of the switching process of a nematic liquid crystal under the influence of an electric field (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 2199-2201 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report a novel optical spectroscopy, time-resolved optical waveguide spectroscopy. This technique was developed in order to investigate the transient behavior of the dielectric constants of thin dielectric medium, e.g., changes of the refractive indices induced by an external trigger such as light, electric field, etc. Optical guided waves propagate in a thin dielectric medium whose optical properties, in particular film thickness and anisotropic dielectric tensor diagonals in molecular and laboratory coordinates, can be evaluated with high accuracy. We employed this technique to a nematic liquid crystal (5CB) as a thin dielectric medium, and molecular reorientation on the switching process was observed through the recording of transient waveguide patterns. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117164
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  • 8
    Electronic Resource
    Electronic Resource
    Structural Characteristics of Human Substantia Nigra Neuromelanin and Synthetic Dopamine Melanins (2000)
    Oxford UK : Blackwell Science Ltd.
    Journal of neurochemistry 75 (2000), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Neuromelanin (NM) is a complex polymer pigment foundprimarily in the dopaminergic neurons of the human substantia nigra. Thestructure of NM is only partially characterized, and its synthesis pathwayremains unknown. We used nuclear magnetic and infrared spectroscopy to examinethe structure of human NM isolated from the substantia nigra compared withsynthetic dopamine melanins. Biochemical analyses were used to investigateproteinaceous and dopaminergic components in these samples. Following acidhydrolysis of NM samples, small amounts of DOPA, dopamine, and a variety ofamino acids were measured. These findings suggest a peptide component in NMstructure. NM also appears to contain a variety of unidentified structuralcomponents possibly derived from the oxidation of dopamine. Human NM differsstructurally from synthetic dopamine melanin, but both human and synthetic NMinclude an aromatic backbone. It is interesting that both human NM andsynthetic melanin also contain a large proportion of aliphatic structures. Ourresults suggest that NM is a more complex pigment than synthetic dopaminemelanin formed via dopamine autoxidation alone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2000.0752583.x
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  • 9
    Electronic Resource
    Electronic Resource
    Inhibitory effects of cortical steroids and adrenocorticotropic hormone on catecholamine secretion in guinea-pig perfused adrenal glands (2002)
    Oxford, UK : Blackwell Science Ltd
    Autonomic & autacoid pharmacology 22 (2002), S. 0 
    Details
    ISSN: 1474-8673
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Chemistry and Pharmacology , Medicine
    Notes: 1 We investigated the effects of exogenously applied steroids and endogenously released cortisol on catecholamine (CA) secretion induced by cholinergic agonists in perfused guinea-pig adrenal glands. 2 Acetylcholine (ACh) and electrical stimulation induced CA secretion, which was reversibly inhibited by cortisol. Adrenocorticotropic hormone (ACTH) increased the concentration of cortisol in the perfusion effluent and partly inhibited the secretory response to ACh. 3 Cortisol or aldosterone dose-dependently inhibited secretory responses to nicotine and muscarine. These inhibitory effects were not antagonized by mifepristone and spironolactone, respective cortisol and aldosterone receptor blockers. 4 Dexamethasone, cortisone, corticosterone, 11-deoxycortisol, 11-deoxycorticosterone, prednisolone and cholesterol inhibited nicotine-evoked CA secretion. The secretory response to muscarine was inhibited by these compounds except for dexamethasone and prednisolone. 5 Dexamethasone, cortisol and aldosterone had no effect on CA secretion induced by high KCl. 6 These results suggest that steroids affect nicotinic and muscarinic ACh receptor-mediated responses through distinct mechanisms, and that cortisol released from the adrenal cortex inhibits CA secretion from the adrenal medulla.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1474-8673.2002.00246.x
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  • 10
    Electronic Resource
    Electronic Resource
    Susceptibility of Helicobacter pylori isolates to metronidazole, clarithromycin and amoxycillin in vitro and in clinical treatment in Japan (1997)
    Oxford, UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 11 (1997), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Primary and acquired resistance to antibiotics is an important factor in determining the reason for treatment failure in Helicobacter pylori infection. We examined the relationship between the susceptibility of H. pylori isolates and the efficacy of chemotherapy.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:The minimal inhibitory concentrations (MICs) of metronidazole (MNZ), clarithromycin (CLAR) and amoxycillin (AMOX) of 320 H. pylori pre-treatment isolates were determined by the agar dilution method. In 290 patients with peptic ulcers, H. pylori infection was treated by dual or triple combination therapies for 2 weeks: one proton pump inhibitor (30 mg/day lansoprazole or 20 mg/day omeprazole) and one or two antibiotics (500 mg AMOX, 200 mg CLAR or 250 mg MNZ twice a day). MICs were also determined after the treatment failure.〈section xml:id="abs1-3"〉〈title type="main"〉Results:Among the drugs tested, for MNZ and CLAR, 8.1% and 9.1% of the isolates, respectively, were resistant, while no isolate was resistant to AMOX. After unsuccessful treatment using MNZ and CLAR, 66.7% and 70.6% of the isolates changed from sensitive to resistant, respectively. All isolates were sensitive to AMOX after treatment failure.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:The failure of the H. pylori treatment results in the induction of resistance to CLAR and/or MNZ. Regimens with a high cure rate should be used in order to prevent the generation of acquired resistance to antibiotics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.1997.00258.x
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