Air Cooler for Crystal Growth in a Laboratory Tube Furnace

Crystallography Reports - A new air cooler design (“specific two-level crystallization incubator”) with a specific arrangement of laboratory vessels by levels and double-branch air...     

Growth mechanisms involved in the synthesis of smooth and microtextured films by acetylene magnetron discharges

The growth of hydrogenated amorphous carbons (a-C:H) produced by continuous or pulsed discharges of acetylene (C(2)H(2)) in an unbalanced magnetron setup was investigated. At 5 × 10(-3) Torr, only smooth films are obtained, whereas at 5 × 10(-1) Torr using a pulsed discharge some microtextured films are formed if the duty cycle is low. The morphology of these microtextured films consists of nanoparticles, filamentary particles, and particular agglomerates ("microflowers"). This paper presents a study of acetylene gas phase polymerization by mass spectrometry, and a detailed analysis of bulk structure of films by combining three techniques which include IR spectroscopy, Raman spectroscopy, and laser desorption/ionization Fourier transform mass spectrometry (LDI-FTMS). Finally, based on the study of gas phase and film structure, we propose a model for the growth of both smooth and microtextured films.     

Developments in MALDI Mass Spectrometry: The Quest for the Perfect Matrix

Abstract

The topic of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has received much attention over the past several years and with the award of the Nobel Prize to Tanaka based on his landmark paper in 1988, has received even more recent attention. This review focuses on the search for an ideal matrix and generally covers the period from the mid 1990's to the present. There have been a number of excellent and comprehensive reviews on MALDI ion formation and a brief summary of some of the most important conclusions is given here. With respect to the applications of MALDI, the present review focuses primarily on polymer analysis, although in this area too, excellent reviews have been published that include consideration of the MALDI method. Although we make some mention of other uses of MALDI (e.g., to proteins and peptides) and other biological applications, we emphasize the polymer uses in the present review.     

Hot topics for mobile services

Upcoming mobile technologies like the Universal Mobile Telecommunications System (UMTS) or Voice-Over-IP/IP Multimedia Subsystem (VoIP/IMS) offer new possibilities but also threats. Consequently, operators and vendors need to adopt appropriate technology and business principles. This article focuses on the concept of Service Platforms to allow flexible and fast service development, and enablers for Location Based Services.     

Using PARLAY APIs Over a SIP System in a Distributed Service Platform for Carrier Grade Multimedia Services

The implementation of new mobile communication technologies developed in the third generation partnership project (3GPP) will allow to access the Internet not only from a PC but also via mobile phones, palmtops and other devices. New applications will emerge, combining several basic services like voice telephony, e-mail, voice over IP, mobility or web-browsing, and thus wiping out the borders between the fixed telephone network, mobile radio and the Internet. Offering those value-added services will be the key factor for success of network and service providers in an increasingly competitive market. In 3GPP's service framework the use of the Parlay APIs is proposed that allow application development by third parties in order to speed up service creation and deployment. 3GPP has also adopted SIP for session control of multimedia communications in an IP network. This article proposes a mapping of SIP functionality to Parlay services and describes a prototype implementation using the SIP Servlet API. Furthermore, an architecture of a Service Platform is presented that offers a framework for the creation, execution and management of carrier grade multimedia services in heterogeneous networks.     

Wide mass range trapping using a 7-T internal source matrix-assisted laser desorption/ionization Fourier transform mass spectrometer

A wide mass range trapping experiment using internal source matrix-assisted laser desorption–Fourier transform mass spectrometry (MALDI–FTMS) was evaluated. In this method, the front trap plate potential is ramped up and the rear trap plate potential is simultaneously decreased using a cubic cell to trap ions over a wide range of mass-to-charge ratios. To apply this to MS/MS experiments, a second ion ejection procedure would remove unwanted ions, with the selected remaining ions then fragmented by collision-induced dissociation. In measurements using a 7.2-T unshielded magnet presented here, an approximately equimolar mixture of a set of poly(ethylene glycol) (PEG) species for the ramped measurements had peak areas of 1.0:1.0:1.0:1.0, as did the previously described integral method which gave peak areas of 1.0:1.1:1.0:1.0, in good agreement with the known composition of the samples deposited on the MALDI probe tip. Comparative MALDI–TOF in reflectron mode results were of similar quality for the equimolar mixture, giving a ratio of 1.0:1.0:1.2:0.9. All methods failed to varying degrees when individual PEG compositions of the trial mixture were changed. However, the previously described integral method showed relatively better results for all but the PEG 8000 doubled mixture.     

Generalized LDPC codes and generalized stopping sets

A generalized low-density parity check code (GLDPC) is a low-density parity check code in which the constraint nodes of the code graph are block codes, rather than single parity checks. In this paper, we study GLDPC codes which have BCH or Reed-Solomon codes as subcodes under bounded distance decoding (BDD). The performance of the proposed scheme is investigated in the limit case of an infinite length (cycle free) code used over a binary erasure channel (BEC) and the corresponding thresholds for iterative decoding are derived. The performance of the proposed scheme for finite code lengths over a BEC is investigated as well. Structures responsible for decoding failures are defined and a theoretical analysis over the ensemble of GLDPC codes which yields exact bit and block error rates of the ensemble average is derived. Unfortunately this study shows that GLDPC codes do not compare favorably with their LDPC counterpart over the BEC. Fortunately, it is also shown that under certain conditions, objects identified in the analysis of GLDPC codes over a BEC and the corresponding theoretical results remain useful to derive tight lower bounds on the performance of GLDPC codes over a binary symmetric channel (BSC). Simulation results show that the proposed method yields competitive performance with a good decoding complexity trade-off for the BSC.