Synthesis and Thermal Behavior of Silica‐Graft‐Polypropylene Nanocomposites Studied by Step‐Scan DSC and TGA

Silica graft poly(propylene) (silica‐g‐PP) nanocomposites were successfully prepared by radical grafting copolymerization and ring‐opening reaction. Their thermal properties were studied by step‐scan differential scanning calorimetry (SDSC) and thermogravimetric analysis (TGA). The exothermic peaks in the IsoK baseline (C_p,IsoK, nonreversing signal) of SDSC reveal that PP and silica‐g‐PP nanocomposites undergo melting‐recrystallization‐remelting during heating. The peak temperatures of recrystallization and remelting shift upward with the existence of nanoparticles in the PP matrix. The thermal degradation kinetics of silica‐g‐PP nanocomposites were investigated using nonisothermal TGA and the Flynn‐Wall‐Ozawa method. The results indicate that the thermal stability was significantly improved with increasing silica content, mainly because of the physical‐chemical adsorption of the volatile degradation products on the nanoparticles that delays their volatilization during decomposition, and the covalent interaction between nanoparticles and PP chains, which will also reduce the breakage of PP backbone chains.     

Z—Scan Characteristics of Cascading Nonlinear Media

We present a method,which combines the Gaussian decomposition method and the “distributed-lens“ method,for analysing Z-scan curves of cascading nonlinear medium layers or a complicated cascading structure.A good agreement with the experimental data is obtained.The method would be useful to design optical limiters and to determine the nonlinearities of cascading medium layers.     

Selection of Acquisition Scan Methods in Intersatellite Optical Communications

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Atom Scan 2000型顺序等离子体发射光谱仪性能初探

本文简介了Atom Scan 2000型顺序等离子体发射光谱仪的主要组合部分和仪器性能；通过实验对该仪器难以掌握的“定准峰位”方面，初步摸索出了在实际中所采用的方法以获得其谱线最大强度值；通过不同数据说明了该仪器在实际应用中的效果；在分析中对光谱线干扰及背景校正方面较难掌握，特别是对扣除背景方面对我们来说还是一个有待于进一步探索的问题。     

Atom Scan 2000型顺序等离子体发射光谱仪性能初探

本文简介了Atom Scan 2000型顺序等离子体发射光谱仪的主要组成部分和仪器性能;通过实验对该仪器难以掌握的"定准峰位"方面,初步摸索出了在实际中所采用的方法以获得其谱线最大强度值;通过不同数据说明了该仪器在实际应用中的效果;在分析中对光谱线干扰及背景校正方面较难掌握,特别是对扣除背景方面对我们来说还是一个有待于进一步探索的问题。     

Focused™ microwave instrumentation from CEM corporation

An overview of the instrumentation for microwave synthesis available from CEM Corp. is provided.     

Correlation of the mechanical properties to the fiber–matrix adhesion of Nextel 312™ fiber/BN/Blackglas™ composites

Boron nitride (BN)-coated aluminoborosilicate (Nextel? 312) fibers, produced via ammonia nitridation, along with 'as-received' and 'desized' fibers, were composited in a silicon oxycarbide (Blackglas?) matrix. The mechanical properties, failure properties, and fiber–matrix interfacial chemistry of the composite were investigated. BN treated fiber composites show a 90% improvement in flexural strength and substantial increases in shear strength (short beam shear and Iosipescu) over the 'as-received' fiber composite. The composite fabricated with 'desized' fibers underwent spontaneous delamination during pyrolization, precluding mechanical testing. X-ray photoelectron spectroscopy of the starting materials and of composite fracture surfaces combined with scanning electron microscopy and energy dispersive X-ray spectroscopy indicate that the locus of failure of the BN-coated fiber composite occurs at the matrix/BN coating interface.     

Intercomparison of Gafchromic™ films,TL detectors and TL foils for the measurements of skin dose in interventional radiology

Several passive solid state dosemeters, such as Gafchromic™ films and thermoluminescence (TL) detectors, are used to estimate and monitor patient skin doses in interventional radiology. To determine the suitability of XR-TypeR Gafchromic™ films and of detectors based on TL materials: pellets, chips and foils to measure skin dose, an intercomparison exercise has been organized within European Dosimetry Radiation Group – Working Group 12 “European Medical ALARA Network” (EURADOS WG12). To test response detectors were exposed to X-ray beams of energies and qualities applied clinically. A blind test was also performed to investigate the accuracy of the dose estimate by detectors exposed to unknown doses. We found the response of films to be strongly dependent on beam quality and filtration (increasing by up to 80% with respect to reference beam quality). The response of TL detectors was found to be less dependent on beam quality (less than 25% variation), with TL foils showing less than 10% variation with respect to reference beam quality. To accurately estimate patient skin doses in interventional radiology it is important to choose the quality of the calibration beam to be as close as possible to the quality of beams actually applied in clinical work.     

An improved HarshawTLD™ extremity dosimeter – DXTRAD beta ring

An improved HarshawTLD? extremity dosimeter system that is rugged in design and easy to wear is presented. This dosimeter is improved from the earlier version (2008) for personnel beta monitoring while still having full range photon performance. The dosimeter style, referred to as DXTRAD, is small in size and has identification by means of a circular barcode. It consists of a detector composed of a thin 7 mg cm^?2 monolayer of HarshawTLD-700H (⁷LiF:Mg,Cu,P) powder and a ring cap with a 3.3 mg cm^?2 entrance window. The use of the TLD-700H TLD material provides a good beta energy response as well as a flat energy response from low energy x-rays to high energy gamma rays. A new assembly tool that improves the consistency of dosimeter geometry and ruggedness for warm and cold sterilization is also developed. With the optimized design, this dosimeter is capable of meeting the stringent energy and angular response requirements of the Physikalisch Technische Bundesanstalt (PTB) for both betas and photons. Presented in this paper are the ISO-12974 and PTB type tests as well as additional operational tests, such as residue, reuse, warm and cold sterilization, and environmental leakage.     

Lattice Boltzmann methods on the ClearSpeed Advance™ accelerator board

Numerical analysts and programmers are currently facing a conceptual change in processor technology. Multicore concepts, coprocessors and accelerators are becoming a vital part in scientific computing. The new hardware techno- logies lead to new paradigms and require adapted methodologies and techniques in numerical simulation. These developments play an important role in computational fluid dynamics (CFD) where many highly CPU-time demanding problems arise. In this paper, we propose a parallel lattice Boltzmann method (LBM) in the context of a coprocessor technology, the ClearSpeed Advance™ accelerator board. Implementations of LBMs on parallel architectures benefit from localities of the necessary interactions and the regular structure of the underlying meshes. The considered board supports high-level parallelism and double precision conforming to the IEEE 754 standard. However, the solution process relies on a huge amount of data which needs to propagate along the mesh. This prototypical fact shows up the bottleneck of internal communication bandwidth and indicates the limits of this type of small-scale parallel systems.     

Use of Adaptive Focused Acoustics™ ultrasound in controlling liposome formation

Many techniques for producing large unilamellar vesicles (LUVs) or small unilamellar vesicles (SUVs) have drawbacks, including exposure of sensitive biological materials to harsh organic solvents or high temperatures. Here we describe the use of controlled focused ultrasound, Adaptive Focused Acoustics™ (AFA), to make LUV or SUV at low temperature without organic solvents and at a consistent, chosen size. We studied the effects of peak incident power (PIP), cycles per burst (CPB), duty factor (DF), temperature, and lipid composition (natural or synthetic), on liposome size distribution. We found that an increase in PIP, DF, CPB, or temperature decreased liposome size. When processed under the same conditions as the natural lipid composition [Phospholipon 90 G], the synthetic lipid composition [HSPC, DSPE-PEG-2000, Chol] generally produced larger liposomes, although extending processing time reduced liposomes to similar size. In combination with AFA, these trends can help pinpoint parameter values that achieve a desired liposome size distribution.     

Cy3B™: Improving the Performance of Cyanine Dyes

The spectral properties of a rigidified trimethine cyanine dye, Cy3B have been characterised. This probe has excellent fluorescent properties, good water solubility and can be bioconjugated. The emission properties of this fluorophore have also been investigated upon conjugation to an antibody. This study compared the conjugated emission properties of Cy3B with other commercially available fluorophores emitting at similar wavelengths.     

Pulse Wavelength Scan of Room-Temperature Mid-Infrared Distributed Feedback Quantum Cascade Lasers for N2O Gas Detection

The tunable diode laser absorption spectroscopy under a pulse wavelength scan scheme is adapted to home-made room-temperature mid-infrared distributed feedback quantum cascade lasers; and identification of N2O spectral fingerprint is demonstrated experimentally. By driving the laser at 800ns pulse duration, a wave number tuning of about 1.6cm^-1 is produced, which make both 1289.04cm^-1 and 1289.86cm^-1 absorption fingerprints of N2O gas to be definitely assigned. The measured relative absorption intensity is consistent with the HITRAN data precisely.     

The pH Probe CypHer™5E is Effectively Quenched by FM Dyes

Concurrent imaging of spectrally distinct fluorescence probes has become an important method for live-cell microscopy experiments in many biological disciplines. The technique enables the identification of a multitude of causal relationships. However, interactions between fluorescent dyes beyond an obvious overlap of their fluorescent spectra are often neglected. Here we present the effects of the well-established fluorescent dyes FM®2-10 or FM®1-43 on the recently introduced pH-dependent probe CypHer?5E. Spectrophotometry as well as live-cell fluorescence microscopy revealed that both FM dyes are effective quenchers of CypHer?5E. Control experiments indicated that this effect is reversible and not due to bleaching. We conclude that, in general, parallel measurements of both dyes are possible, with low FM dye concentrations. Nevertheless, our results implicate that special care has to be taken in such dual colour experiments especially when analysing dynamic CypHer?5E signals in live-cell microscopy.     

Comparative study of reductive amination reaction on 5-(4-formyl-3,5-dimethoxyphenoxy)valeric acid and its monomethoxy analog using the Multipin™ approach

The 5-(4-formyl-3,5-dimethoxyphenoxy)valeric acid (Barany)linker and its monomethoxy analog were applied to theMultipin method of solid phase synthesis. Acomparative assessment of reductive amination and cleavage ofthese linkers under conditions of multiple synthesis indicatedthat both were applicable to a broad range of primary aminesincluding aniline and 4-nitroaniline. Apart from the greaterlability of the dimethoxy version under TFA cleavage, there wasno observable advantage of one linker over the other within thedescribed experiment.     

Electrical impedance spectroscopy of ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate (ECOENG™ 110)

Ionic liquid “ECOENG? 110”, a promising electrolyte for electrochemical devices, was investigated by impedance spectroscopy. Metallic electrodes (Pt, Cu, Ag, and Mo) as well as carbon were used for the electrochemical characterization. The dependences of the real and imaginary impedance, polarization resistance and electrochemical capacity of the double layer on the electrode potential were investigated using electrical equivalent circuits of R₁(QR₂) and R₁[Q(R₂W)] types.