Search results

Filter

Filetype

Your search for "*" yielded 546556 hits

Wave splitting in the time domain for a radially symmetric geometry

A decomposition of the field of the wave equation in three dimensions is suggested. This wave splitting decomposes the field into two components such that in free space simple propagation properties are obtained. The inhomogeneous region is assumed to have a phase velocity variation that varies only in the radial coordinate r from the origin. The suggested wave splitting is a generalization of the

On the M-function and Borg-Marchenko theorems for vector-valued Sturm-Liouville equations

We will consider a vector-valued Sturm-Liouville equation of the form R[U]:=-(PU')(')+QU=lambdaWU, xis an element of[0,b), with P-1, W, Qis an element ofL(loc)(1)([0,b))(mxm) being Hermitian and under some additional conditions on P-1 and W. We give an elementary deduction of the leading order term asymptotics for the Titchmarsh-Weyl M-function corresponding to this equation. In the special case o

Custom DSP Design of a GSM Speech Coder

The GSM speech coder for digital mobile telephones has been designed on a custom DSP using an environment for development of arbitrary processor architectures. A netlist of the speech coder has been generated from a high level description in a presented design environment. Improvement of the performance both by modifying the high level description and by hand optimization of the microcode is discu

Biochemical Studies of Semenogelins with Emphasis on Zinc-Binding Properties

Semenogelins I and II (SgI and SgII) are homologous and rapidly evolving proteins that have a repetitive primary structure and are synthesized mainly in the seminal vesicles. Upon ejaculation, a gelatinous coagulum is formed when the semenogelin-rich secretion from the seminal vesicles is mixed with the prostate secretion, which contains high concentrations of zinc(II) and proteases. These proteas

Estimating LAI in deciduous forest stands

The leaf area index (LAI), was estimated in deciduous forests of southern Sweden using different estimation techniques. The effective LAI (L-e) was estimated optically by measurements with the gap fraction instrument LAI-2000 and corrections for the aggregation of leaves were achieved by using the TRAC (Tracing Radiation and Architecture of Canopies) instrument. Two methods for correcting the cont

Structure-activity relationship in HC-SCR of NOx, by TEM, O-2-chemisorption, and EDXS study of Ag/Al2O3

Ag/alumina catalysts with different silver loading (1.28 - 6 wt %) for lean NO reduction activity were prepared by impregnation and the incipient wetness method. Complementary HRTEM, HAADF, O-2-chemisorption, and EDXS studies were applied to investigate the dependence between silver particle size and catalytic activities of the prepared materials. The catalyst with the lowest silver loading (1.28

Mind in Motion: The utilization of noise in the cognitive process

Popular Abstract in Swedish "Tanken i rörelse" handlar dels om hur tanken sätts i rörelse av brus och dels om hur detta brus kan användas av hjärnan för att fånga upp visuell rörelse. Ofta betraktas brus som en störning, men detta arbete försöker visa att brus kan ha en viktig funktion i tankeprocessen. Arbetet vill visa hur våra tankar växer fram ur det bakgrundsbrus som alltid finns i hjärnan i The brain is not silent. Even in the absence of stimuli are the neurons activated every now and then in what is called "spontaneous" or "background activity" which provides a noisy background to the operation of the brain. This work shows how this noise can be utilized in the cognitive process. That is, rather than being treated as a nuisance, noise is given a functional role in the brain´s activi

Toll-like Receptors in Allergic Rhinitis

Popular Abstract in Swedish Allergisk rinit är en immunförmedlad sjukdom som huvudsakligen drabbar nässlemhinnan. Vid kontakt med allergen, t.ex. pollen, uppkommer typiska symptom såsom klåda, nysningar, rinnsnuva och nästäppa. Immunförsvaret brukar traditionellt indelas i två samverkande delar, den medfödda och den förvärvade delen. Den medfödda delen aktiveras snabbt vid en första kontakt med miAllergic rhinitis is an inflammatory disorder with the characteristic symptoms itching, sneezing, secretion and blockage upon allergen contact. In addition to the local inflammation in the nose, there is a systemic component that influences peripheral blood, bone marrow and lungs. The immune system is conventionally divided into innate and acquired (adaptive) immunity. The former is important in

Some reflections on relationships between structure, properties, and performance of engineering materials

The main object of materials science and technology is relationships between structure and properties. The practical use of engineering materials also involves consideration of things other than current theories for such relationships. Uncertainties of various kinds prompt reflections on the validity and applications of common practice based on experience. Among other things, this is true for deci

First results from the high resolution XUV undulator beamline BW3 at HASYLAB

Initial results from the XUV undulator beamline at the 4.5 GeV storage ring DORIS are reported. The beamline consists of three different undulators mounted on a revolver type device and a modified SX-700 plane grating monochromator with a spherical focusing mirror. It covers the spectral range from 50–2000 eV with excellent spectral resolution and high photon flux. In the energy range 400 eV to 1

Terpenoids from Bovista sp 96042

The novel cytotoxic hexacyclic illudane-illudalane bis-sesquiterpene bovistol (la) was obtained from the basidiomycete Bovista sp. 96042, together with several new sesquiterpenes. la is formed in the fungus by a heteroatom Diels-Alder dimerisation of psathyrellon B (2). (C) 2002 Elsevier Science Ltd. All rights reserved.

Aspects on Interference and Diversity in Wireless Networks

Popular Abstract in Swedish Denna avhandling behandlar två ämnen inom trådlös kommunikation: interferens mellan frekvenshoppande (FH) nätverk och fleranvändardiversitet. I arbetet på FH nätverk undersöks ett system där frekvenshopp används för att möjliggöra samtidig tillgång till kanalen för multipla okoordinerade nätverk. Detta åstadkoms genom att frekvenshoppen sker varje gång ett ny paket skaThis thesis deals with two topics in wireless communications: interference between frequency-hopping (FH) networks, and multiuser diversity. The work on FH treats a system where FH is used to provide simultaneous access to the channel for multiple uncoordinated wireless networks. This is achieved by performing frequency hops on a packet-by-packet basis, and letting the sequence of hopping frequen

Graphics for the masses: a hardware rasterization architecture for mobile phones

The mobile phone is one of the most widespread devices with rendering capabilities. Those capabilities have been very limited because the resources on such devices are extremely scarce; small amounts of memory, little bandwidth, little chip area dedicated for special purposes, and limited power consumption. The small display resolutions present a further challenge; the angle subtended by a pixel i