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  • 2000-2004  (23)
  • 1970-1974  (1)
  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 4810-4812 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The magneto-impedance (MI) of glass-coated Fe–Ni–Cu microwires was investigated for longitudinal radio-frequency (rf) currents up to a frequency of 200 MHz using a rf lock-in amplifier method. The MI, defined as ΔZ/Z=[Z(H)−Z(H=0.3 T)]/Z(H=0.3 T), displays a peak structure (negative MI) at zero field for rf currents with frequencies less than 20 MHz and this crosses over to a sharp dip (positive MI) at higher frequencies. This crossover behavior is ascribed to the skin-depth-limited response primarily governed by the field-dependence of the permeability. Large saturation fields (300 to 600 Oe) and other anomalies indicate the possible influence of giant magneto-resistance (GMR) on the MI. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 7398-7400 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Fe3O4 thin film prepared by pulsed laser deposition on Si (100) substrate has been investigated by transmission electron microscopy from plane and cross-sectional views. The thin film, which shows a spinel structure as characterized by selected-area diffraction, is about 180 nm thick with granular growth of particle size about 50 nm. High resolution electron microscopy observations indicate reduced thickness of the native SiO2 layer between the thin film and Si due to rastering of the substrate surface by an unfocused laser beam before the deposition. By using a 220 diffraction spot in two beam condition near the 〈001〉 axis of a single Fe3O4 grain, antiphase boundaries (APBs) inside the grains could be clearly resolved. The existence of APBs in the thin film is consistent with the magnetic experiments including an open hysteresis loop and unsaturated magnetization in relatively high magnetic fields. This study suggests that APBs are not unique to Fe3O4 films grown on MgO substrates. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 4172-4174 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Highly (100) oriented Ba0.9Sr0.1TiO3/LaNiO3 heterostructures have been grown on Si(100) using chemical solution routes. X-ray diffraction analysis shows that Ba0.9Sr0.1TiO3 thin films are high (100) orientation (α100=0.92). Atomic force microscopy investigation shows that they have large grains about 80–200 nm. A Pt/Ba0.9Sr0.1TiO3/LaNiO3 capacitor has been fabricated and showed excellent ferroelectricity, the remnant polarization and coercive field are 10.8 μC/cm2 and 96 kV/cm, respectively. The electric field dependence of capacitance measurement shows that the capacitor has large capacitance tuning ([Cmax−Cmin]/Cmax×100%) of 63%. The Ba0.9Sr0.1TiO3 thin films have high dielectric constant (cursive-epsilon) of 200 at 1 MHz. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 2449-2451 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A comprehensive theoretical model describing the amplification of picosecond optical pulses in midinfrared intersubband semiconductor optical amplifiers is developed, taking into account gain dispersion, short carrier relaxation time and ultrafast nonlinear refraction. It is shown that these factors are extremely important in determining the amplified optical pulse characteristics in both the time and frequency domains. The calculations also indicate that gain dispersion can be significantly enhanced by fast carrier relaxations, short pulse widths, and high pulse energies. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 79 (2001), S. 3476-3478 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: PbZr0.5Ti0.5O3/La0.5Sr0.5CoO3 (PZT/LSCO) heterostructures have been grown directly on (100)Si by chemical solution routes. Field-emission scanning electron microscopy and x-ray diffraction analysis show that PZT and LSCO thin films are polycrystalline and entirely perovskite phase. PZT thin films grown on LSCO thin films showed no preferential orientation and excellent ferroelectricity. The remnant polarization Pr is about 22.8 μC/cm2 and the coercive field Ec is about 95 kV/cm at an applied electric field of 400 kV/cm. The ferroelectric capacitor has been fabricated and showed no polarization fatigue after 3×109 fatigue cycles. The Pt/PZT/LSCO capacitor is suitable for nonvolatile random access memory application. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 15 (2001), S. 0 
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Trials of thymosin treatment in chronic hepatitis B virus infection have been small and the results have been inconsistent.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To conduct a meta-analysis to evaluate the efficacy of thymosin treatment in chronic hepatitis B virus infection.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Randomized controlled trials comparing thymosin for over 24 weeks vs. placebo (or usual care) in the treatment of chronic hepatitis B virus infection were identified through MEDLINE, EMBASE and the Cochrane Register of Clinical Trials. Biochemical (normalization of transaminases) and virological (loss of hepatitis B virus DNA and hepatitis B e antigen) responses were analysed using the intention-to-treat method. The odds ratio was used to measure the magnitude of the efficacy.〈section xml:id="abs1-4"〉〈title type="main"〉Results:Five trials (353 patients) were identified. The odds ratio (95% confidence interval) of the virological response of thymosin over placebo at the end of treatment, 6 months post-treatment and 12 months post-treatment were 0.56 (0.2–1.52), 1.67 (0.83–3.37) and 2.67 (1.25–5.68), respectively. There was an increasing trend of the virological response with time since the cessation of thymosin treatment (P=0.02). There was no difference in the biochemical response between the thymosin and placebo groups at the end of treatment, 6 months post-treatment and 12 months post-treatment.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:Thymosin is effective in suppressing viral replication in chronic hepatitis B virus infection, but the effect is delayed until 12 months after the cessation of treatment.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 69 (2004), S. 0 
    ISSN: 1750-3841
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: : Thermal resistance of Clostridium sporogenes (PA 3679) was determined at 115.6 °C, 118.3 °C, and 121.1 °C (240 °F, 245 °F, and 250 °F, respectively) in phosphate buffer (pH 7.0) and mashed potatoes (pH 6.3) using aluminum thermal-death-time (TDT) tubes developed at Washington State Univ. D-values were 1.8, 1.1, and 0.62 min in phosphate buffer and 2.2, 1.1, and 0.61 min in mashed potatoes at 115.6 °C, 118.3 °C, and 121.1 °C, respectively. Z-values were 12 °C and 10 °C in phosphate buffer and mashed potatoes, respectively. The thermal inactivation kinetic results were then used to validate a novel thermal process based on 27.12 MHz radio frequency (RF) energy. Trays of mashed potatoes inoculated with PA 3679 were subjected to 3 processing levels: target process (F0∼4.3), under-target process (F0∼2.4), and over-target process (F0∼7.3). The microbial challenge test data showed that microbial destruction from the RF process agreed with the calculated sterilization values. This study suggests that thermal processes based on RF energy can produce safe and shelf-stable packaged foods.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1750-3841
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A 915-MHz Microwave-Circulated Water Combination (MCWC) heating technology was validated for a macaroni and cheese product using inoculated pack studies. Before the tests, heat resistances of a Clostridium sporogenes (PA 3679) spore crop were determined in neutral phosphate buffer and macaroni and cheese product. Trays of macaroni and cheese products were subjected to 3 processing levels: target process (F0= 2.4), under target process (F0= 1.2), and over target process (F0= 4.8). The inoculated packs were evaluated by count-reduction method and end-point method. The microbial results showed that microbial destruction resulting from MCWC heating technology matched the calculated degree of sterilization (F0 value). This study suggests that the MCWC heating technology has potential in sterilizing packaged foods.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 68 (2003), S. 0 
    ISSN: 1750-3841
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: : A study was conducted with a pilot-scale sterilization system based on 27-MHz radio frequency (RF) energy to investigate the effectiveness in shortening process time and in improving quality for foods sealed in 6-pound military-ration polymeric trays. Chemical marker M-1 was used to evaluate heating uniformity in 20% whey protein gels as a model food, and macaroni and cheese was processed to assess the influence of RF process on product quality. With the RF system, a lethality (F0= 10 min) was achieved in both model food and macaroni and cheese within 30 min with relative uniform heating, compared to a 90 min conventional retort process that delivered a similar lethality.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 67 (2002), S. 0 
    ISSN: 1750-3841
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: : The quality retention characteristics of strawberry and carrot purees dried using the Refractance WindowTM (RW) drying method were evaluated against freeze drying, drum drying, and spray drying methods. Ascorbic acid retention of the strawberry purees (94.0%) after RW drying was comparable to 93.6% in freeze-drying. The carotene losses for RW drying were 8.7% (total carotene), 7.4% (α-carotene), and 9.9% (β-carotene), which were comparable to losses of 4.0% (total carotene), 2.4% (α-carotene), and 5.4% (β-carotene) for freeze-dried carrot purees. The color of the RW-dried carrot purees was comparable to fresh puree. For RW-dried strawberry purees, the color retention was comparable to freeze-dried products. RW drying altered the overall perception of aroma in strawberries.
    Materialart: Digitale Medien
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