Refine
Year of publication
- 2007 (40) (remove)
Document Type
- Conference Proceeding (20)
- Article (reviewed) (4)
- Book (4)
- Part of a Book (4)
- Contribution to a Periodical (4)
- Article (unreviewed) (2)
- Periodical Part (1)
- Report (1)
Conference Type
- Konferenzartikel (13)
- Konferenzband (4)
- Konferenz-Abstract (2)
- Konferenz-Poster (1)
Keywords
- CDMA (2)
- Mikroelektronik (2)
- Abwasser (1)
- Bioelektrochemische Brennstoffzelle (1)
- Chromatographie (1)
- Codierung (1)
- Elektrizitätserzeugung (1)
- Emission (1)
- Energietechnik (1)
- FFF (1)
Institute
Open Access
- Closed Access (11)
- Open Access (11)
- Closed (8)
- Bronze (5)
In thin-layer chromatography, fiber-bundle arrays have been introduced for spectral absorption measurements in the UV-region. Using all-silica fiber bundles, the exciting light will be detected after re-emission on the plate with a fiberoptic spectrometer. In addition, fluorescence light can be detected which will be masked by the re-emitted light. Therefore, it is helpful to separate the absorption and fluorescence on the TLC-plate. A modified three-array assembly has been developed: using one array for detection, the two others are used for excitation with broadband band deuterium-light and with UV-LEDs adjusted to the substances under test. As an example, the quantification of glucosamine in nutritional supplements or spinach leaf extract will be described. Using simply heating of the amino-plate for derivation, the reaction product of Glucosamine can be detected sensitively either by light absorption or by fluorescence, using the new fiber-optic assembly. In addition, the properties of the new 3-row fiber-optic array and the commercially available UV-LEDs will be shown, in the interesting wavelength region for excitation of fluorescence, from 260 nm to 360 nm. The squint angle having an influence on coupling efficiency and spatial resolution will be measured with the inverse farfield method. Some properties of UV-LEDs for analytical applications will be described and discussed, too.
Solartechnik
(2007)
Design of next-generation cdma using orthogonal complementary codes and offset stacked spreading
(2007)
This article presents an innovative code-division multiple access system architecture that is based on orthogonal complementary spreading codes and time-frequency domain spreading. The architecture has several advantages compared to conventional CDMA systems. Specifically, it offers multiple-access-interference-free operation in AWGN channels, reduces co-channel interference significantly, and has the potential for higher capacity and spectral efficiency than conventional CDMA systems. This is accomplished by using an "offset stacked" spreading modulation technique followed by quadrature amplitude modulation, which optimizes performance in a fading environment. This new spreading modulation scheme also simplifies the rate matching algorithms relevant for multimedia services and IP-based applications.
This paper focuses on the effects of differential mode delay (DMD) on the bandwidth of multimode optical fibres. First an analytical solution for the computation of the differential mode time delay is presented. The electrical field of each mode is calculated by the numerical solution of the Helmholtz equation. Based on this solution the modal power distribution as well as the fibre's impulse response under different launching conditions can be obtained.
Next, the refractive-index profile of two fibres is modelled on the basis of DMD measurements. It is shown that these measurements provide enough information to predict the fibre's propagation characteristics under different launch conditions (excitation conditions).