Picosecond pulse generation by intracavity nonlinear compression in self-injected Nd-YAG laser

A new type of laser which generates pulses with amplification band-limited picosecond duration is presented. 15 ps, 0.9 GW, 3 pps, λ = 1.06 μm in a single pulse are obtained with good stability. Accurate timing of the pulses can be achieved and no external pulse selection is required.     

Zinnbestimmung durch Titration mit Methylenblau

Zusammenfassung Das von Atack eingeführte Verfahren zur Bestimmung des ZinnII-chlorids mit M-blau wurde nachgeprüft und der quantitative Ablauf der Reaktion durch gewichtsanalytische Einstellung der ZinnIV-chlorid-lösung und durch Kontrolle auf jodometrischem Wege bestätigt.Wolframate, Vanadate und Molybdate stören nach erfolgter Reduktion die Titration und dürfen daher nicht zugegen sein. Das Verfahren der Titration von ZinnII-salzen mit M-blau ist nur für die Analyse von wolframfreien Zinnerzen geeignet, nicht aber für die Analyse von Zinn-Wolframerzen. Das Verfahren ist jedoch zur Zinnbestimmung immer anwendbar, wenn die Abwesenheit von Wolfram festgestellt wurde. Auf Grund der bei der Reduktion in Gegenwart von Wolfram eintretenden Blaufärbung kann die An- bzw. Abwesenheit von Wolfram erkannt werden, so daß man dann gegebenenfalls die Titration des ZinnII-Chlorids mit M-blau ausführen kann.Bei veränderter Arbeitsweise besteht die Möglichkeit, die Titration des ZinnII-Chlorids mit M-blau auch bei der Analyse von Zinn-Wolframerzen auszuführen. Die entsprechenden Untersuchungen werden später mitgeteilt werden.Sind Blei-(Antimon)-verbindungen neben Zinn in der Probe enthalten, so muß das bei der Reduktion mit Aluminium abgeschiedene Metall abfiltriert und die Reduktion wiederholt werden. Wismut- und Kupferverbindungen bleiben bei einem Superoxydaufschluß im Rückstand, andernfalls muß die bei der Reduktion abgeschiedene Metallmenge ebenfalls abfiltriert und die Reduktion wiederholt werden. ManganIonen stören nicht, ebensowenig Alkalien und Eisen und Nickel in den Mengen, in denen sie durch Aufschluß in die Lösung gelangen.     

Effect of the solvent on growth and properties of polyaniline-based composite films

In this study, we report on the electrosyntheses of polyaniline (PAni) and PAni/magnetite nanoparticle (PAni/Fe₃O₄-NP) composite films by a potentiodynamic method from water and ethanol solutions. The aim of the study is to evaluate the effect of the solvent on the electrochemical growth of these films. The growth cyclic voltammograms and the mass change variation (Δm), determined by the electrochemical quartz crystal microbalance technique, show that the polymer growth rate is lower in ethanol than in water (Δm in water is ca. 50% higher than in ethanol after 30 voltammetric cycles). As a consequence, the films grown from ethanol show a more compact and uniform morphology, as we observed with scanning electron microscopy. Furthermore, the formation of oxidation products is inhibited in ethanol. The PAni/Fe₃O₄-NP composite films electrosynthesized in ethanol showed enhanced electrochemical response than the composite films grown from water. This is attributed to the better dispersion of the nanoparticles in this solvent and consequently in the polymer matrix, as confirmed by the Δm value and the spectroscopic characterization. We conclude that electropolymerization from ethanol solution provides high-quality PAni and PAni/Fe₃O₄-NP composite films; the electrochemical and morphological properties of these films suggest that their use for corrosion protection is promising.     

Highly hydrophobic sisal chemithermomechanical pulp (CTMP) paper by fluorotrimethylsilane plasma treatment

Fluorinated thin layers were created on chemithermomechanical pulp (CTMP) sisal paper surfaces with fluorotrimethylsilane (FTMS) radio frequency-plasma conditions. It was found that the FTMS-discharge environments caused implantation of fluorine and –Si(CH₃) _x groups into the surface layers of the paper substrates. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy and Electron Spectroscopy for Chemical Analysis, as well as Atomic Force Microscopy and Scanning Electron Microscopy analyses revealed a smooth surface for the FTMS plasma-treated paper, apparently covered completely with a cross-linked polymerized network. Although the plasma reaction takes place with the cellulose, hemicelluloses and lignin, it appears that the chemical linkage is mainly to the lignin component on the CTMP paper surface by means of mainly C–O–Si–F, with some C–Si–F structures. The CTMP fibers apparently have a high lignin surface concentration. The water absorption for the plasma-treated CTMP paper was reduced from greater than 300 to 17 g of water/m² and the contact angle increased from less than 15° to greater than 120° the strength properties were only slightly reduced and the brightness was essentially unaffected with the FTMS plasma treatment.     

A novel,integrated forensic microdevice on a rotation‐driven platform: Buccal swab to STR product in less than 2 h

This work describes the development of a novel microdevice for forensic DNA processing of reference swabs. This microdevice incorporates an enzyme‐based assay for DNA preparation, which allows for faster processing times and reduced sample handling. Infrared‐mediated PCR (IR‐PCR) is used for STR amplification using a custom reaction mixture, allowing for amplification of STR loci in 45 min while circumventing the limitations of traditional block thermocyclers. Uniquely positioned valves coupled with a simple rotational platform are used to exert fluidic control, eliminating the need for bulky external equipment. All microdevices were fabricated using laser ablation and thermal bonding of PMMA layers. Using this microdevice, the enzyme‐mediated DNA liberation module produced DNA yields similar to or higher than those produced using the traditional (tube‐based) protocol. Initial microdevice IR‐PCR experiments to test the amplification module and reaction (using Phusion Flash/SpeedSTAR) generated near‐full profiles that suffered from interlocus peak imbalance and poor adenylation (significant ?A). However, subsequent attempts using KAPA 2G and Pfu Ultra polymerases generated full STR profiles with improved interlocus balance and the expected adenylated product. A fully integrated run designed to test microfluidic control successfully generated CE‐ready STR amplicons in less than 2 h (<1 h of hands‐on time). Using this approach, high‐quality STR profiles were developed that were consistent with those produced using conventional DNA purification and STR amplification methods. This method is a smaller, more elegant solution than current microdevice methods and offers a cheaper, hands‐free, closed‐system alternative to traditional forensic methods.