Ultra-high-resolution large-dynamic-range optical fiber static strain sensor using Pound-Drever-Hall technique

We report the realization of a fiber-optic static strain sensor with ultrahigh resolution and large dynamic range for the applications of geophysical research. The sensor consists of a pair of fiber-Bragg-grating-based Fabry-Perot interferometers as sensor heads for strain sensing and reference, respectively. The Pound-Drever-Hall technique is employed to interrogate the sensor heads, and a cross-correlation algorithm is used to figure out the strain information with high precision. Static strain resolution down to 5.8 nanostrains is demonstrated. The dynamic range can be extended up to hundreds of microstrains, and the measuring period is a few tens of seconds.     

Highly atom efficient catalytic reactions utilizing water and alcohols as reagents

In this accounts, we describe our recent studies on hydrolysis, alcoholysis, and addition of alcohols to organic molecules. The reactions utilizing water and alcohols as a reagent are one of the most basic and simple reactions. The palladium-catalyzed asymmetric hydrolysis and alcoholysis of vinyl ethers gave valuable axially chiral 1,1′-bi-2-naphthol and 1,1′-bi-2-phenol derivatives and chiral P-chirogenic compounds in optically active form. The reaction is applied for hydrolytic deallylation of N-allyl amide and allyl esters. The later one was achieved by palladium/ruthenium dual catalysts which is the first example of catalytic irreversible ester hydrolysis. Gold complexes also catalyzed vinyl ether alcoholysis and hydroalkoxylation of olefins. In the later reaction, simple unactivated olefins can be used as substrates and gave the product in 92% yield. The copper-DTBM-SEGPHOS complex catalyzed alcoholysis of azlactones which is the first example showing zero-order kinetic resolution.     

Prospects for sympathetic cooling of molecules in electrostatic, ac and microwave traps

We consider how trapped molecules can be sympathetically cooled by ultracold atoms. As a prototypical system, we study LiH molecules co-trapped with ultracold Li atoms. We calculate the elastic and inelastic collision cross sections of ⁷LiH + ⁷Li with the molecules initially in the ground state and in the first rotationally excited state. We then use these cross sections to simulate sympathetic cooling in a static electric trap, an ac electric trap, and a microwave trap. In the static trap we find that inelastic losses are too great for cooling to be feasible for this system. The ac and microwave traps confine ground-state molecules, and so inelastic losses are suppressed. However, collisions in the ac trap can take molecules from stable trajectories to unstable ones and so sympathetic cooling is accompanied by trap loss. In the microwave trap there are no such losses and sympathetic cooling should be possible.     

Urinary arsenic species in an arsenic‐affected area of West Bengal,India (part III)

Arsenic contamination of groundwater has long been reported in the Mushidabad district of West Bengal, India. We visited 13 arsenic‐affected families in the Makrampur village of the Beldanga block in Mushidabad during 18–21 December 2001 and collected five shallow tubewell‐water samples used general household purposes, four deep tubewell‐water samples used for drinking and cooking purposes, and 44 urine samples from those families. The arsenic concentrations in the five shallow tubewell‐water samples ranged from 18.0 to 408.4 ppb and those in the four deep tubewell‐water samples were from 5.2 to 9.6 ppb. The average arsenite (arsenic(III)), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and arsenate (arsenic(V)) in urine were 28.7 ng mg^?1, 168.6 ng mg^?1, 25.0 ng mg^?1 and 4.6 ng mg^?1 creatinine respectively. The average total arsenic was 227.0 ng mg^?1 creatinine. On comparison of the ratio of (MMA + DMA) to total arsenic, the average proportion was 86.7 ± 9.2% (mean plus/minus to residual standard deviation, n = 43). The exception was data for one boy, whose proportion was 8.0%. One woman excreted the highest total arsenic, at 2890.0 ng mg^?1 creatinine. When using 43 of the urine samples (the exception being the one sample obtained from the boy) there were significantly positive correlations (p < 0.01) between arsenic(III) and MMA, between arsenic(III) and DMA and between MMA and DMA. Copyright © 2005 John Wiley & Sons, Ltd.     

Analytical methods and monitoring system for E-beam flue gas treatment process

The results of reliable and precise measurement of gas composition in different key points of e-beam installation are necessary for its proper operation and control. Only the composition of flue gas coming into installation is adequate to composition of flue gas emitted from coal-fired boiler. At other points of e-b installation the gas composition is strongly modified by process conditions therefore specific measuring system (sampling and conditioning system and set of gas analyzers) for its determination are required. In the paper system for gas composition measurement at inlet and outlet of e-b installation are described. Process parameters are continuously monitoring by CEM system and occasionally by the grab sample system. Both system have been tested at pilot plant at EPS Kaw czyn.     

Beam Shaping Optics for YAG Laser Processing Fabricated by Computerized Numerical Control Lathe

A method for a beam shaping optics is proposed to convert a laser beam profile into arbitrary required intensity distribution. Surface profile of the beam shaping optics is designed by using Snell's law to convert the required intensity distribution at the beam irradiation plane from the input intensity distribution. A computerized numerical control (CNC) lathe is employed to fabricate the beam shaping optics, and acrylic resin is used for the material. The acrylic resin plate is cut by a ball type of grinding wheel tool consisted on diamond powder and polished by a cone type felt buff with alumina ceramics powder. The CNC lathe is powerful tool to control the position of these tools. The fabricated beam shaping optics is aspheric shape with 4 mm of thickness and it works to convert the intensity distribution of multi-mode beam profile with 13 mm of diameter into a flat top cylinder with 1 mm of diameter. A working distance of the beam shaping optics is 60 mm, and its transmittance is over 98%. It succeeds to fabricate uniform melting mark of 0.6 mm diameter on a steel target by the YAG laser process.