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  • 1
    Electronic Resource
    Electronic Resource
    On the use of the thermal wave resonator cavity sensor for monitoring hydrocarbon vapors (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 2928-2932 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A gas sensing device based on a thermal wave resonator cavity is outlined. It is experimentally tested by monitoring the presence of several hydrocarbon vapors in air via the measurement of the thermal diffusivity. It is also shown that its time-dependent response may be used to follow the vapor diffusion. It is shown that its characteristic response time is linearly correlated to the thermal diffusivity value of the mixture. The steps toward the development of a practical sensing device are further discussed. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150712
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  • 2
    Electronic Resource
    Electronic Resource
    Photoacoustic thermal characterization of spark-processed porous silicon (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 8951-8954 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A non-separation approach to determine the spark-processed porous silicon thermal parameters is presented. This thermal characterization was performed through application of the photoacoustic technique, in combination with compositional models for spark-processed porous silicon samples. The thermal parameters obtained are in agreement with existing studies about the composition of this material. This approach opens the possibility of performing the thermal characterization of other porous semiconductors and analogous materials. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362626
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  • 3
    Electronic Resource
    Electronic Resource
    Photoacoustic determination of non-radiative carrier lifetimes (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 2604-2609 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: From photoacoustic (PA) experiments we determine the nonradiative carrier lifetime in direct band-gap semiconductors. We use the Rosencwaig and Gerscho model to calculate the PA signal in semiconductors taking into account the distinction between non-radiative and radiative carrier lifetimes. We have assumed that for our high quality crystalline samples, the main contribution to the non-radiative processes comes from CHCC and CHSH Auger recombination for n and p-type materials, respectively. For GaAs, InSb and GaSb samples, the experimental data obtained by means of an open photoacoustic cell were fitted to the theoretical model and we show that the values we determined for the non-radiative recombination lifetime agree well with those reported in the literature. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.367022
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  • 4
    Electronic Resource
    Electronic Resource
    Application of the thermal wave resonator to the measurement of the thermal diffusivity of gas mixtures (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 1580-1582 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A gas analyzer device based on thermal wave interference in a cavity is presented. The thermal diffusivity of CO2:air mixtures as a function of the relative concentration is measured. It is demonstrated that different concentrations of CO2 in air can be detected with accuracy using the described experimental device. The results presented here open the possibility to perform routine measurements of thermal diffusivity of binary gas mixtures and using this parameter to monitor the relative gas concentration. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1334622
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  • 5
    Electronic Resource
    Electronic Resource
    Monitoring of hydrocarbon vapor diffusion in air using a thermal wave interferometer (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 5581-5586 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A discussion on the use of thermal wave interference (TWI) for the monitoring of the transients of hydrocarbon in air is presented. The thermal wave signal was modeled using the logarithm-mixing model for the thermal diffusivity of a two-phase gas system in which the hydrocarbon vapor concentration in the air-filled TWI cell is a varying function of time. The time varying hydrocarbon vapor concentration was described assuming the simple Fick's model for mass diffusion of the hydrocarbon vapor in the stagnant air column of the TWI cell. The transient TWI signal amplitude data fitting yielded two parameters, namely, the saturation concentration and the characteristic diffusion time. From the corresponding values of the diffusion time the hydrocarbon mass diffusivities were straightforwardly obtained. The obtained values for the hydrocarbon mass diffusivities were found to be in good agreement with the ones reported in the literature. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1465104
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  • 6
    Electronic Resource
    Electronic Resource
    Transcript levels of AtMRPs after cadmium treatment: induction of AtMRP3 (2003)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 26 (2003), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In yeasts, the ABC-type transporters are involved in vacuolar sequestration of cadmium. In plants, transport experiments with isolated vacuoles indicate that this is also true. In order to know more about the response of AtMRPs, a subclass of Arabidopsis ABC transporters, to cadmium, their expression pattern was analysed using the microchip technology and semi-quantitative reverse transcriptase-polymerase chain reaction. From 15 putative sequences coding for AtMRPs, transcript levels were detected for 14. All were expressed in the roots as well as in the shoots, although at a different level. In 4-week-old Arabidopsis, transcript levels of four AtMRPs were up-regulated after cadmium treatment. In all cases up-regulation was exclusively observed in the roots. The increase of transcript levels was most pronounced for AtMRP3. A more detailed analysis revealed that induction of AtMRP3 could also be observed in the shoot when leaves were cut and cadmium allowed to be taken up in the shoot. In young plantlets, a far higher portion of Cd2+ was translocated in the aerial part compared with adult plants. Consequently, AtMRP3 transcript levels increased in both root and shoot of young plants. This suggests that 7-day-old seedlings do not exhibit such a strict root–shoot barrier as 4-week-old plants. Expression analysis with mutant plants for glutathione and phytochelatin synthesis as well as with compounds producing oxidative stress indicate that induction of AtMRP3 is likely due to the heavy metal itself.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.2003.00968.x
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of Heat Treatment on Bovine Lactoperoxidase Activity in Skim Milk: Kinetic and Thermodynamic Analysis (2003)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 68 (2003), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: : The effect of heat on lactoperoxidase activity in bovine milk was studied over a range of 68 to 76 °C. Values of residual enzymatic activity after different treatments were studied by kinetic analysis, obtaining D-values and the Z-value (3.1 °C). Denaturation of lactoperoxidase, measured by loss in activity, can be described as a 1st-order reaction. Rate constants were calculated, as was the energy of activation, which was 737.69 kJ/mol. Thermodynamic parameters were also calculated. The high value obtained for the variation in enthalpy of activation indicates that a high amount of energy is required to initiate denaturation, probably due to the molecular conformation of lactoperoxidase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.2003.tb14120.x
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  • 8
    Electronic Resource
    Electronic Resource
    Validation of roughhead grenadier (Macrourus berglax) otolith reading (2002)
    Berlin Germany : Blackwell Verlag GmbH
    Journal of applied ichthyology 18 (2002), S. 0 
    Details
    ISSN: 1439-0426
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Roughhead grenadier Macrourus berglax Lacépède 1802, is becoming an important commercial fish in the north-west Atlantic fisheries and reliable age information is needed for its assessment. Macrourus berglax has been aged by counting otolith growth zones assumed to represent anulli. Three validation methods were applied: back-calculation of length-at-age, length–frequency analysis, and analyses of the progression of the length mode of an exceptionally large year class. Results on size-at-age estimated by otolith growth zone counts, length–frequency analysis of pre-anal fin length and modal progression were internally consistent, but estimates by back-calculation were different. This latter method produces unrealistic growth curves for each sex due to the weak relationship between otolith size as measured and pre-anal fin length. Up to age 8–9 the size-at-age were the same for males and females; thereafter males were smaller than females. Male growth rate declined when pre-anal fin length reached 18 cm at around age 9, whereas the growth of females started to decline at about 30 cm at around age 16. The Von Bertalanffy growth model derived from otolith analysis was similar to that obtained by the Multifan length frequency analysis model, and gave realistic values of Linf, close to the maximum anal fin lengths found in catches. The results showed that Macrourus berglax has a prolonged life cycle and differences in growth between males and females.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0426.2002.00330.x
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  • 9
    Electronic Resource
    Electronic Resource
    VH Gene Repertoire of Mantle Cell Lymphomas (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 764 (1995), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1995.tb55873.x
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  • 10
    Electronic Resource
    Electronic Resource
    Modal characteristics of few-mode silica-based photonic crystal fibres (2000)
    Springer
    Optical and quantum electronics 32 (2000), S. 963-970 
    Details
    ISSN: 1572-817X
    Keywords: dispersion ; optical fibres ; optical waveguides ; photonic crystal fibres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The modal characteristics of silica-based photonic crystal fibres (PCF) are examined through a scalar modal analysis combined with an effective V-parameter model using a finite-difference method. Cut off frequencies of the lowest-order modes and the normalised dispersion curves are given and are found to be quasi-independent of the hole-size-to-pitch ratio. A simple and accurate empirical relation for the cutoff wavelength is given for the first higher-order mode for fibres with hole-size-to-pitch ratio below 0.7. These results should be very useful in designing PCF's for various applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007091217711
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