Client-server-based LBS architecture: A novel positioning module for improved positioning performance

Permission to distribute obtained from publisher.This work presents a new efficient positioning module that operates over client-server LBS architectures. The aim of the proposed module is to fulfil the position information requirements for LBS pedestrian applications by ensuring the availability of reliable, highly accurate and precise position solutions based on GPS single frequency (L1) positioning service. The positioning module operates at both LBS architecture sides; the client (mobile device), and the server (positioning server). At the server side, the positioning module is responsible for correcting user’s location information based on WADGPS corrections. In addition, at the mobile side, the positioning module is continually in charge for monitoring the integrity and available of the position solutions as well as managing the communication with the server. The integrity monitoring was based on EGNOS integrity methods. A prototype of the proposed module was developed and used in experimental trials to evaluate the efficiency of the module in terms of the achieved positioning performance. The positioning module was capable of achieving a horizontal accuracy of less than 2 meters with a 95% confidence level with integrity improvement of more than 30% from existing GPS/EGNOS services

Size effect in ion transport through angstrom-scale slits

It has been an ultimate but seemingly distant goal of nanofluidics to controllably fabricate capillaries with dimensions approaching the size of small ions and water molecules. We report ion transport through ultimately narrow slits that are fabricated by effectively removing a single atomic plane from a bulk crystal. The atomically flat angstrom-scale slits exhibit little surface charge, allowing elucidation of the role of steric effects. We find that ions with hydrated diameters larger than the slit size can still permeate through, albeit with reduced mobility. The confinement also leads to a notable asymmetry between anions and cations of the same diameter. Our results provide a platform for studying effects of angstrom-scale confinement, which is important for development of nanofluidics, molecular separation and other nanoscale technologies

Observational detection of meteor-produced VLF electromagnetic radiation

In November 1998, Croatian Physical Society's expedition to Mongolia was undertaken. The goal was to make measurements of the puzzling electrophonic sounds and very low frequency (VLF) radio emission from meteors during the anticipated Leonid meteor storm. During the night of 16/17 November 1998, an extremely high fireball activity of the Leonid meteors occured. During this period, we performed measurements of the VLF radiation from meteors. Here we present a positive signal which consists of a sequence of sharp, short VLF bursts, coincident with the appearance of meteor that was recorded by the video camera. This is the first completely controlled instrumental recording of such an event

Opažanje niskofrekventnog elektromagnetskog zračenja proizvedenog meteorom

In November 1998, Croatian Physical Society\u27s expedition to Mongolia was undertaken. The goal was to make measurements of the puzzling electrophonic sounds and very low frequency (VLF) radio emission from meteors during the anticipated Leonid meteor storm. During the night of 16/17 November 1998, an extremely high fireball activity of the Leonid meteors occured. During this period, we performed measurements of the VLF radiation from meteors. Here we present a positive signal which consists of a sequence of sharp, short VLF bursts, coincident with the appearance of meteor that was recorded by the video camera. This is the first completely controlled instrumental recording of such an event.Ekspedicija Hrvatskog fizikalnog društvo uputila se u Mongoliju u studenom 1998 radi promatranja očekivane kiše meteora i mjerenja neobičnih elektrofonskih šumova i niskofrekventnog elektromagnetskog zračenja proizvedenog meteorima. U noći 16/17 studenog 1998. došlo je do izrazito pojačane aktivnosti sjajnih meteora Leonida. U tom smo periodu mjerili elektromagnetske valove VLF i istovremeno snimali meteore. Ovdje izvješćujemo o zabilježenom signalu elektromagnetskih valova koji se sastojao od niza kratkotrajnih niskofrekventnih impulsa, koji se pojavio istovremeno s meteorom. Ovo je prvo instrumentalno bilježenje te pojave načinjeno u potpuno kontroliranim uvjetima

Opažanje niskofrekventnog elektromagnetskog zračenja proizvedenog meteorom

In November 1998, Croatian Physical Society\u27s expedition to Mongolia was undertaken. The goal was to make measurements of the puzzling electrophonic sounds and very low frequency (VLF) radio emission from meteors during the anticipated Leonid meteor storm. During the night of 16/17 November 1998, an extremely high fireball activity of the Leonid meteors occured. During this period, we performed measurements of the VLF radiation from meteors. Here we present a positive signal which consists of a sequence of sharp, short VLF bursts, coincident with the appearance of meteor that was recorded by the video camera. This is the first completely controlled instrumental recording of such an event.Ekspedicija Hrvatskog fizikalnog društvo uputila se u Mongoliju u studenom 1998 radi promatranja očekivane kiše meteora i mjerenja neobičnih elektrofonskih šumova i niskofrekventnog elektromagnetskog zračenja proizvedenog meteorima. U noći 16/17 studenog 1998. došlo je do izrazito pojačane aktivnosti sjajnih meteora Leonida. U tom smo periodu mjerili elektromagnetske valove VLF i istovremeno snimali meteore. Ovdje izvješćujemo o zabilježenom signalu elektromagnetskih valova koji se sastojao od niza kratkotrajnih niskofrekventnih impulsa, koji se pojavio istovremeno s meteorom. Ovo je prvo instrumentalno bilježenje te pojave načinjeno u potpuno kontroliranim uvjetima

Embedding a Carbon Nanotube across the Diameter of a Solid State Nanopore

A fabrication method for positioning and embedding a single-walled carbon nanotube (SWNT) across the diameter of a solid state nanopore is presented. Chemical vapor deposition (CVD) is used to grow SWNTs over arrays of focused ion beam (FIB) milled pores in a thin silicon nitride membrane. This typically yields at least one pore whose diameter is centrally crossed by a SWNT. The final diameter of the FIB pore is adjusted to create a nanopore of any desired diameter by atomic layer deposition, simultaneously embedding and insulating the SWNT everywhere but in the region that crosses the diameter of the final nanopore, where it remains pristine and bare. This nanotube-articulated nanopore is an important step towards the realization of a new type of detector for biomolecule sensing and electronic characterization, including DNA sequencing.Engineering and Applied SciencesMolecular and Cellular BiologyPhysic

Generalized Elliott-Yafet theory of electron spin relaxation in metals: the origin of the anomalous electron spin life-time in MgB2

The temperature dependence of the electron spin relaxation time in MgB2 is anomalous as it does not follow the temperature dependence of the resistivity above 150 K, it has a maximum around 400 K, and it decreases for higher temperatures. This violates the well established Elliot-Yafet theory of electron spin relaxation in metals. We show that the anomaly occurs when the quasi-particle scattering rate (in energy units) becomes comparable to the energy difference between the conduction- and a neighboring band. We find that the anomalous behavior is related to the unique band structure of MgB$_2$ and the large electron-phonon coupling. The saturating spin-lattice relaxation can be regarded as the spin transport analogue of the Ioffe-Regel criterion of electron transport

Anisotropy of superconducting MgB2 as seen in electron spin resonance and magnetization data

We have observed the conduction electron spin resonance (CESR) in fine powders of MgB2 both in the superconducting and normal states. The Pauli susceptibility is chi_s=2.0*10^{-5} emu/mole in the temperature range of 450 to 600 K. The spin relaxation rate has an anomalous temperature dependence. The CESR measured below T_c at several frequencies suggests that MgB_2 is a strongly anisotropic superconductor with the upper critical field, H_c2, ranging between 2 and 16 T. The high-field reversible magnetization data of a randomly oriented powder sample are well described assuming that MgB_2 is an anisotropic superconductor with H_c2^{ab} / H_{c2}^{c} \approx 6--9.Comment: 4 pages, 4 eps figure