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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 6107-6112 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation of CF2(Double Bond)CFCl at 193 nm has been studied by product translational spectroscopy. Results show that the molecule undergoes competing dissociation into three pairs of products: (1) CFCl+CF2, (2) C2F2Cl+F, and (3) C2F3+Cl with a relative yield of 1.0:∼0.1:1.4. When photolyzed with polarized laser light, reactions (1) and (3) were detected with fragments recoiling anisotropically, indicating that dissociation occurs primarily on the excited potential energy surface. From the maximum kinetic energy derived for reactions (2) and (3), a upper limit of 110 and 90 kcal/mol was determined for the C–F bond and the C–Cl bond dissociation energy, respectively. In addition to these primary dissociation channels, we have observed the secondary products, CF+CF2 and F+C2F2 from the primary fragment C2F3 by absorbing an additional photon. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 5331-5338 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation of CH2(Double Bond)CClF at 193 nm has been studied by product translational spectroscopy. A total of five primary dissociation channels was detected for the products of Cl (fast), HCl, HF, Cl (slow), and F in the decreasing order of relative yield. Product translational energy distributions have been measured for these reaction products. While a thermal-like distribution was detected for the slow Cl and F atoms, a nonthermal distribution was determined for the fast Cl atom and the molecular elimination of HCl and HF. Apart from the fast Cl atom with anisotropy parameter β=0.5, the remaining products recoil isotropically following photolysis with linearly polarized light. By analogy with the photodissociation of chloroethylenes, these products are found to originate from two potential energy surfaces. In addition to the primary dissociation channels, we have detected the secondary products of F+C2H2 from the internally excited α-fluorovinyl radical through a fast fragment isomerization. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    International journal of cosmetic science 27 (2005), S. 0 
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A high-performance liquid chromatography method has been developed for simultaneous determination of triclosan (2,4,4-trichloro-2-hydroxydiphenyl ether) and triclocarban (3,4,4-trichlorocarbanilide) in cosmetic and pharmaceutical products. The two compounds could be separated on a Nucleosil C18 column and eluted with acetonitrile and water (70:30, v/v) as the mobile phase and detected with a differential refractive index detector. The retention times of triclosan and triclocarban were 5.81 and 2.99 min, respectively. The results obtained were in good agreement with those obtained by a differential pulse voltammetric method.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 8046-8053 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experimental results on amorphous rare earth and transition metal alloys suggest the presence of Fe-rich clusters. A model is proposed in which the magnetic units are magnetic clusters. The magnetization of the clusters decreases with the increase of temperature. In this model, there are two critical temperatures, Tcsystem and Tccluster. Tccluster is the Curie temperature of the magnetic clusters, which is also the Curie temperature of the sample. Tcsystem is the measurement of the strength of interactions between clusters. Between Tccluster and Tcsystem, the system exhibits superparamagnetism with strong cluster interactions. The strong cluster interactions result in the ferromagnetic state below the critical temperature (Tcsystem), which is called a cluster ferromagnetism. Our experimental data (magnetization curves and susceptibility values of amorphous Y60Fe30Al10 and Nd60Fe30Al10 ribbons) support the cluster ferromagnetic model. The zero temperature coercivity and the relationship between Tblock and Tcsystem are also discussed in this article. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 4435-4437 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Metal vacuum arc plasma sources enhance the capability of plasma immersion ion implantation (PIII) by providing a convenient and efficient means by which to introduce metallic ions into the plasma for metallic ion implantation and/or thin film deposition. The power supply of a metal vacuum arc plasma source is usually based on the artificial transformation line design, but it has several drawbacks. For instance, the pulse width cannot be adjusted conveniently and the pulsing frequency cannot exceed a predefined value. These restrictions make process optimization and synchronization with the sample high voltage modulator complicated in pulsed-mode PIII operation. In this work, we experimentally investigate the voltage–current characteristics of our metal vacuum arc plasma source. Our results suggest two different power supply designs. By adopting the design incorporating a gradual voltage–current decline, we successfully construct a simple and reliable power supply that works in a stable manner for a prolonged period of time. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 6408-6414 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Grain growth and strain release processes in the electrodeposited nanocrystalline (nc) Cu specimen with a high purity were investigated by means of differential scanning calorimetry, x-ray diffraction, electrical resistance measurement, and high-resolution transmission electron microscopy. It was found that for the as-deposited nc Cu, the grain growth started at about 75 °C, at which the microstrain in (111) plane (e111) began to release, while the mean microstrain and that in (100) plane (e100) began to release at a higher temperature (150 °C). With an increment in microstrain in the nc Cu introduced by cold rolling, the grain growth onset temperature increased while the strain release onset temperature dropped obviously. These results showed an evident correlation between the grain size stability and the microstrain in the nc materials. The activation energy for the grain growth was determined by using Kissinger analysis and isothermal kinetics analysis, being about 86 kJ/mol, implying that the grain growth process is dominated by grain boundary diffusion. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 7511-7513 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: There is growing evidence that in magnetic films of thickness less than 20 nm there can be significant change in the values of magnetic anisotropy constant and magnetoelastic coupling from those of bulk materials. While phenomenological models based on Néel's idea of surface anisotropy may offer a partial explanation, it is vital to develop a more mechanistic understanding. Recently the potential contribution of interface and surface strains to the observed property change has been highlighted. Here we report the field emission gun TEM and electron spectroscopic images of the structure of the interface region between Fe50Co50 and Ag, the local crystallographic texture and the distribution of Ag in magnetostrictive Fe50Co50/Ag multilayers. The results are correlated with the bulk measurements of coercivity and the saturation magnetostriction constant. For the first time it is possible to provide a degree of microstructural interpretation of the magnetic data. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 4917-4921 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have performed outgoing resonant Raman scattering and photoluminescence measurements on as-grown, Be- and C-implanted GaN in the temperature range of 77–330 K. In implanted GaN after postimplantation annealing at 1100 °C, the A1(LO) multiphonons up to the seventh order were observed with the very strong four longitudinal optical (LO) and five LO modes at ∼2955 and ∼3690 cm−1, respectively, showing extraordinary resonance behavior. With the sample temperature, these two modes significantly decreased and increased in intensity, respectively. The phenomenon is attributed to the variation of resonant conditions due to the shift of the band gap energy. Meanwhile, the combination of E2(high) and quasi-LO phonons was strongly enhanced by quasi-LO phonon involvement and thus the corresponding overtones can be clearly observed even up to the sixth order (m=6). The mechanisms that such strong outgoing multiphonon resonance Raman scattering occurred to implanted GaN instead of high-quality as-grown GaN samples can be attributed to the strong Frohlich-induced scattering by LO phonons and exciton-mediated resonant Raman scattering with impurity inducement. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 4236-4240 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ferromagnetic Nd0.7Sr0.3MnO3 (NSMO) films have been prepared onto (001) SrTiO3 by the off-axis magnetron sputtering technique. The NSMO films are characterized by resistivity measurements, x-ray diffraction, and the atomic force microscope. Under our deposition conditions the films show a maximum resistivity (ρmax) at the highest peak temperature of Tp=180–240 K. By increasing the deposition temperature, Tp shifts to lower temperature and ρmax increases. In an applied magnetic field, large magnetoresistance (MR) ratios 〉2200% for several in situ deposited films at 180 K and H=6 T are obtained. The influence of growth conditions on the magnetotransport properties of NSMO films and their MR characteristics are discussed. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 115 (2001), S. 3195-3200 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation of 1,2-C2H2Br2 at 248 nm has been studied by product translational spectroscopy. The results show that the molecule dissociates exclusively into the products (1) Br2+C2H2 and (2) Br (fast)+Br (slow)+C2H2 with a branching ratio ∼0.2:0.8. While the cleavages of the C–Br bonds are not symmetric, producing the Br atoms at unequal velocities, the anisotropy of the products indicates that both reactions occur in a fraction of a rotational period. Following an asynchronous concerted reaction, the triple products were simulated with the P(Et) distributions coupled by asymmetric angular distributions. A mechanism consistent with the measured results is proposed that the Br2 elimination is a result of a fast intersystem crossing from the ππ* pumped state while the triple products occur via a simultaneous asymmetric scission of the C–Br bonds along the nσ* state. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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