Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 3317-3322 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: X-ray diffraction measurements have been made on the nematic phase of T15 (4-cyano-4'-n-pentyl-p-terphenyl), as well as on the nematic and smectic A phases of RNO2 [4'-nitrophenyl-4-(4'-n-hexyloxy-benzoyloxy)-cinnamate]. The x-ray equipment used allows comparably high resolution measurements of liquid crystals. The inner reflexes show that both compounds possess a bilayer structure supposed as overlapping of polar cyano or nitro group of one molecule and the phenyl ring of the neighboring molecule. The molecular orientational distribution function f (β) has been calculated on the basis of intensity simulations of the outer reflexes. The orientational order parameter P2(cos β), P4(cos β), 〈P2〉 and 〈P4〉 have been determined from f (β). A strong decrease of 〈P2〉 and 〈P4〉 is observed at the smectic A–nematic phase transition temperature of RNO2.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 2742-2746 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A very small capacitive sensor for measuring thermal expansion and magnetostriction of small and irregular shaped samples has been developed. A capacitive method with tilted plates is used. The tilted plate capacitance formula is used for the calculation of the capacitor gap, the calibration is performed by measuring the signal of a standard material. The active length of the sample can be less than 1 mm. The absolute resolution is about 1 Å. All mechanical connections of the dilatometer are carried out by tiny Cu–Be springs, enabling the small force on the sample to be adjusted (50–500 mN) and no additional sample fixing is necessary. The cell has been tested in the temperature range 0.3–200 K and in static magnetic fields up to 15 T. The zero signal of the dilatometer has been determined by measuring a silver sample. The correct operation and reproducibility has been verified by measuring the thermal expansion of Cu. The thermal expansion and magnetostriction of a DyCu2 single crystal has been determined. The advantage of this method compared to specific heat measurements is that a large temperature range can be covered with one equipment. This high static and dynamic range of sample length, temperature, and magnetic field suggests a number of possible applications, like the investigation of crystal field effects on the magnetoelastic properties of single crystals or structural phase transitions. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 4178-4186 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The capture and emission of electrons at single, individual interface traps is studied in sub-μm metal–oxide–semiconductor field-effect transistors (MOSFETs) by the random telegraph signals (RTSs) they induce by source-drain conductance modulations. The magnitude of the RTSs observed frequently exceeds 10% of the channel conductance and it exhibits a large scatter over two orders of magnitude. Analytical estimates and computer modeling show that the magnitude of the RTSs and the scatter cannot occur for a uniform MOSFET channel. It is concluded that fixed oxide and interface charge centers, which are present in the active device area at a high concentration, cause a percolating current distribution in the channel. The lucky trap centers located close to current paths give rise to large RTSs. The scatter in the magnitude of the RTSs is due to the random location of traps in the percolation pattern. Trapping centers causing RTSs thus act as atomic probes of the nonuniform current distribution in the channel. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 1734-1741 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The switching amplitude of random telegraph signals (RTSs) caused by trapping a single electron at an individual interface defect is studied in sub-μm-sized metal oxide field-effect transistors (MOSFETs). The amplitudes of RTSs depend on the channel nonuniformity and, in particular, on the current distribution in the immediate vicinity of the trap. We find that to a good approximation the RTS amplitude is proportional to the square of the local current density. This mathematical relation is tested and verified with the help of a computer simulation. RTS amplitudes may thus be used as atomic probes of the local current density. By the evaluation of 187 RTS amplitudes in different MOSFETs of the same type, we deduce for the first time a histogram showing the magnitude distribution of the local current density in such devices. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 2210-2212 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Characteristic intra 4f-shell luminescence spectra of Nd3+(4f3) have been observed from neodymium-implanted gallium phosphide and gallium arsenide. The luminescent centers were found to occupy different types of noncubic lattice sites, presumably formed by association of the neodymium implants with radiation damage centers. The relative intensities of the neodymium luminescent centers were found to depend critically on the conditions of postimplantation thermal annealing.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 4877-4879 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using a tunable color center laser, photoluminescence excitation measurements were performed on GaAs:Er grown by molecular-beam epitaxy. These measurements show that only one type of Er3+ center is responsible for the sharply structured emission band at 1.54 μm. The multiplicity of the zero-phonon lines indicates that this Er3+ center has lower than cubic symmetry and that the luminescence arises from the intracenter transition 4I13/2→4I15/2 of Er3+ (4f 11).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 1202-1204 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Implantation of neodymium (Nd) in GaP gives rise to a very complex spectrum of intra 4f-shell luminescence transitions involving a number of Nd defect associates. Using a tunable color center laser, photoluminescence excitation spectroscopy was employed to separate different Nd3+ complexes in GaP:Nd. Two dominant noncubic Nd centers are clearly identified which arise presumably from the association of Nd with radiation damage centers.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The q-profile measurement presented in this article is based on the observation of pellets injected into the plasma and viewed with a fast-framing camera. The pellets sublimate in the plasma and the ablated material is ionized. The ions move along the magnetic field lines, while an ablation cloud is forming. This ablation cloud contains a small fraction of neutral particles which emit visible light after collisional excitation. It is therefore possible to visualize the magnetic field lines along which the pellet passes. The inclination angle of the magnetic field lines with respect to the torus midplane can be determined from this observation. The results are compared with the inclination angles delivered by an equilibrium code. Further analysis shows that it is not meaningful to determine the q-profile from the data of only the pellet ablation, in the case of an elongated plasma as in ASDEX Upgrade. However, the accuracy of the q-profile determined by an equilibrium code, especially in the plasma center, can be greatly improved by using the pellet measurements as additional input data. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 1634-1636 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An evaporated nanometer scale granular film provides a simple system for studying Coulomb blockade effects. This technique has often been used during the last few decades. However with respect to potential devices, specific problems continue to obstruct broader application. It is virtually impossible to observe Coulomb blockade in one–dimensional structures, and even for wide two–dimensional systems the yield is frustratingly low. We study these problems using a comprehensive theoretical framework that enables us to model both the growth aspects, and the electrical characteristics. In particular, we study how the morphology of the islands influences their electrical properties. Explanations for the observed behavior are put forward. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 52 (1997), S. 0 
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The allergic potential of α-caseins from bovine, ovine, and goat's milk sharing more than 85% identical amino acids was compared. Caseins were purified by anion-exchange chromatography and used for a specific IgE and IgG ELISA with diluted human sera. Sera were from 17 children with immediate-type allergy to cow's milk, from 59 children with atopy but without food allergy, and from 27 healthy children without atopic disease. The sera of cow's milk-allergic children showed a significantly higher IgE and IgG binding to α-caseins from all three species than the sera of the other groups. All groups showed an increased antibody binding to bovine a-casein compared to the sheep and goat proteins, but the differences were significant only in the groups of atopic children and of healthy controls. Furthermore, inhibition of the IgE binding to bovine α-casein with α-casein from cow, goat, and sheep revealed that the a-caseins from these species are highly cross-reactive, on the basis of the small differences in their primary structure. In conclusion, the milk of goat and sheep harbor an allergic potential and is not suitable for the nutrition of milk-allergic patients.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...