A high sampling rate digital holographic imager instrument for the in situ measurements of hydrometeors

A novel digital in-line holographic imaging instrument designed for acquiring properties of individual hydrometeors in situ is presented. The instrument has a large measurement volume of 670 cm³. This combined with fast frame rate imaging and software controlled multi-exposure capabilities results in a representative sampling of rain and snowfall events. Hydrometeors are measured and analyzed from the in-focus images with microscopic resolution, and their 3D locations inside the measurement volume are determined. The instrument is designed to operate in cold climates and to produce reliable measurements also during strong winds. The imaging rate of the instrument was designed to be adequately high to observe the dynamic nature of rain and snow falls. By recording multi-exposure holograms, the effective frame rate can be increased. This allows the measurements of the velocities of the fast-falling hydrometeors. The instrument and the hologram processing are described; as well as results from laboratory tests and the first field measurements are shown. As a result, the resolving power of the instrument was measured to vary between 11 and 18 microns inside the measurement volume near the center of the field-of-view. Velocity vectors were measured both from multi-exposure and high frame rate holograms. The measured velocities ranged from 0.1 to 4 m/s. In addition, the projections of a flat-shaped and rotating snowflake imaged at different locations inside the measurement volume demonstrated the possibility to estimate the shape of the hydrometeor from multiple viewing angles.     

Vapor–liquid equilibrium for binary system of tetrahydrothiophene + 2,2,4-trimethylpentane and tetrahydrothiophene + 2,4,4-trimethyl-1-pentene at 358.15 and 368.15 K

Isothermal vapor–liquid equilibrium (VLE) for tetrahydrothiophene + 2,2,4-trimethylpentane and tetrahydrothiophene + 2,4,4-trimethyl-1-pentene at 358.15 and 368.15 K were measured with a circulation still. All systems studied exhibit positive deviation from Raoult's law. No azeotropic behavior was found in all systems at the measured temperatures. The experimental results were correlated with the Wilson model and compared to COSMO-SAC predictive model. Analyses of liquid and vapor phase composition were determined with gas chromatography. All VLE measurements passed the three thermodynamic consistency tests used. The activity coefficients at infinite dilution are also presented.     

Selective Inhibitors of FKBP51 Employ Conformational Selection of Dynamic Invisible States

The recently discovered SAFit class of inhibitors against the Hsp90 co‐chaperone FKBP51 show greater than 10 000‐fold selectivity over its closely related paralogue FKBP52. However, the mechanism underlying this selectivity remained unknown. By combining NMR spectroscopy, biophysical and computational methods with mutational analysis, we show that the SAFit molecules bind to a transient pocket in FKBP51. This represents a weakly populated conformation resembling the inhibitor‐bound state of FKBP51, suggesting conformational selection rather than induced fit as the major binding mechanism. The inhibitor‐bound conformation of FKBP51 is stabilized by an allosteric network of residues located away from the inhibitor‐binding site. These residues stabilize the Phe67 side chain in a dynamic outward conformation and are distinct in FKBP52, thus rationalizing the basis for the selectivity of SAFit inhibitors. Our results represent a paradigm for the selective inhibition of transient binding pockets.     

Developments in WTDM technology for high-capacity optical studio networks

This paper reviews results achieved in high-capacity optical networking for television studios under RACE projects 1036 and 2001. A network based on wavelength- and time-division multiplexing (WTDM) has been demonstrated, which, using 16 wavelengths, provides a total capacity of 39.8 Gbit s^-1. We summarize previously reported results obtained in the system test-bed, which demonstrate the distribution of uncompressed digital video signals ranging from PAL at 142 Mbit s^-1 to HDTV at 1.15 Gbit s^-1. The process of further developing this technology for a pilot installation has established that it will be applicable not only to central routeing within a television studio but also to resilient network provision and the interconnection of remote sites. We review how network resilience is achieved by multiple interconnected star architectures and outline how recent results with integrated star couplers suggest that these designs can be delivered at low cost. We report new experiments demonstrating an optically amplified network over a commercially installed 36-km link, thus confirming the feasibility of a long-reach routeing system. We also report results illustrating how lithium niobate devices can perform optical switching on the wavelength multiplex and thus offer potential advantages in system transparency and throughput. Our conclusion is that we have confirmed the feasibility of the WTDM concept and demonstrated its potential for wider application.GEC-Marconi Defence SystemsThomson-CSFNorthern Telecom Europe     

Phénylation d'alcools allyliques acycliques : II. Regioselectivite du transfert d'hydrogene

PdCl₂, HNaCO₃-catalysed phenylation of deuterium-labelled allylic butenols, a Heck type reaction, proceeds by a highly regioselective 1,2-hydrogen shift $\text{via}$ a Wacker type intermediate. No decomplexed enol was formed during this reaction.     

Rapid Cationization of Gold Nanoparticles by Two‐Step Phase Transfer

Cationic gold nanoparticles offer intriguing opportunities as drug carriers and building blocks for self‐assembled systems. Despite major progress on gold nanoparticle research in general, the synthesis of cationic gold particles larger than 5 nm remains a major challenge, although these species would give a significantly larger plasmonic response compared to smaller cationic gold nanoparticles. Herein we present the first reported synthesis of cationic gold nanoparticles with tunable sizes between 8–20 nm, prepared by a rapid two‐step phase‐transfer protocol starting from simple citrate‐capped particles. These cationic particles form ordered self‐assembled structures with negatively charged biological components through electrostatic interactions.     

Glass microfabricated nebulizer chip for mass spectrometry

A microfluidic nebulizer chip for mass spectrometry is presented. It is an all-glass device which consists of fusion bonded Pyrex wafers with embedded flow channels and a nozzle at the chip edge. A platinum heater is located on the wafer backside. Fabrication of the chip is detailed, especially glass deep etching, wafer bonding, and metal patterning. Various process combinations of bonding and metallization have been considered (anodic bonding vs. fusion bonding; heater inside/outside channel; metallization before/after bonding; platinum lift-off vs. etching). The chip vaporizes the liquid sample (0.1-10 microL min(-1)) and mixes it with a nebulizer gas (ca. 100 sccm N2). Operating temperatures can go up to 500 degrees C ensuring efficient vaporization. Thermal insulation of the glass ensures low temperatures at the far end of the chip, enabling easy interconnections.     

Improved lower bound for locating-dominating codes in binary Hamming spaces

Designs, Codes and Cryptography - In this article, we study locating-dominating codes in binary Hamming spaces $$\mathbb {F}^n$$ . Locating-dominating codes have been widely studied since their...     

Vapor–liquid equilibrium for the binary systems tetrahydrothiophene + toluene and tetrahydrothiophene + o-xylene at 368.15 K and 383.15 K

Isothermal vapor–liquid equilibrium (VLE) for tetrahydrothiophene + toluene and tetrahydrothiophene + o-xylene at 368.15 K and 383.15 K was measured with a recirculation still. Liquid- and vapor-phase compositions were determined with gas chromatography. All systems exhibit a small positive deviation from Raoult's law and show nearly ideal behavior. All VLE measurements passed the point test used. The experimental results were correlated with the Wilson model and compared with COSMO-SAC predictive models. COSMO-SAC predictions show a slight negative deviation from Raoult's law for all systems measured. Raoult's law can be used to describe all systems studied. The activity coefficients at infinite dilution are presented.     

Phase equilibria for systems containing dimethyl disulfide and diethyl disulfide with hydrocarbons at 368.15 K

Isothermal vapor–liquid equilibrium (VLE) for dimethyl disulfide + toluene, dimethyl disulfide + 2,2,4-trimethylpentane, dimethyl disulfide + 2,4,4-trimethyl-1-pentene, and diethyl disulfide + 2,2,4-trimethylpentane at 368.15 K were measured with a recirculation still. All systems exhibit positive deviation from Raoult's law. Dimethyl disulfide + toluene system shows only slight positive deviation from Raoult's law, while dimethyl disulfide + 2,2,4-trimethylpentane, dimethyl disulfide + 2,4,4-trimethyl-1-pentene, and diethyl disulfide + 2,2,4-trimethylpentane systems show larger positive deviation from Raoult's law. Maximum pressure azeotropes were found in systems: dimethyl disulfide + toluene (x₁ = 0.632, P = 66.4 kPa, T = 368.15 K), dimethyl disulfide + 2,2,4-trimethylpentane (x₁ = 0.311, P = 95.8 kPa, T = 368.15 K), and dimethyl disulfide + 2,4,4-trimethyl-1-pentene (x₁ = 0.295, P = 88.4 kPa, T = 368.15 K). No azeotropic behavior was observed in system diethyl disulfide + 2,2,4-trimethylpentane at 368.15 K. The experimental results were correlated with the Wilson model. Original UNIFAC was used to predict dimethyl disulfide + 2,2,4-trimethylpentane and diethyl disulfide + 2,2,4-trimethylpentane systems at 368.15 K. COSMO-SAC predictive model was used to predict infinite dilution activity coefficients for all systems measured. Liquid and vapor-phase composition were determined with gas chromatography. All VLE measurements passed the thermodynamic consistency tests applied. The activity coefficients at infinite dilution are also presented.