[en] The Motional Stark Effect (MSE) diagnostic will be essential for the study of advanced scenarios on ITER and its design is currently underway. In order meet the ITER MSE diagnostic design requirements, two approaches for the measurement are under consideration. The first is based on standard polarimeter techniques to measure the polarization of the emitted light, whereas the second measures the Stark splitting from which |B| can be inferred, where |B| is the magnitude of the total magnetic field. The baseline design of the optical system is centered on the first approach. Emphasis in this case is placed on minimizing the polarization aberrations of the optical relay system. Motivation for the second method results from concern that the optical properties of the plasma-facing mirror, particularly its diattenuation and retardance, will degrade with plasma exposure. The second approach, while less sensitive to aberrations induced by plasma exposure effects, requires greater optical throughput in order to measure the complete Stark spectrum. We have developed optimized designs for both techniques and will present a comparison of them and discuss the associated design trade-offs

[en] We report a cesium sulfonate metal organic framework (Cs₃(L)(H₂O)_3.3, 1, L = 1,3,5-trisulfonato-2,4,6-trihydroxybenzene) with hydrated channels that conduct protons at 1.1 x 10^-5 S cm^-1 at 50% relative humidity and 70 ^oC. Water was crystallographically observed in the structure, and the likely proton-transfer pathway was studied. The material was not robust, and appropriate parameters were employed to ensure meaningful data were extracted from the study. (author)

[en] Some number of quality indicators of the detection is to be improved: the rate of participation (R.E. > 70 %), the positive predictive value of the biopsy (R.E.=75 %) and the proportion of cancers detected without a ganglionic invasion (R.E. > 70 %). (N.C.)

[en] The chemical reactivity of hydrogen-passivated surface of silicon nanowires (SiNWs) towards the reductive deposition of silver and copper ions from solution is reported. SiNWs synthesized by laser ablation were used in the investigation. The surface properties of SiNWs after the removal of the surface oxide were studied. It is found that the surface silicon of the SiNWs can readily reduce silver (I) and copper (II) ions to metal aggregates of various morphologies on the SiNW surface at room temperature. The reaction products have been characterized with scanning electron microscopy, energy dispersive x-ray spectroscopy, high-resolution transmission electron microscopy, electron energy loss spectroscopy, and x-ray photoelectron spectroscopy. By varying the concentration of Ag(I) ions in the solution, nanostructures of silver with different shapes and sizes can be obtained. This approach for synthesis of metal nanostructures offers a potential method for the preparation of desired metal catalysts. [copyright] 2001 American Institute of Physics

[en] The motional Stark effect (MSE) diagnostic will be essential for the study of advanced scenarios on ITER and its design is currently underway with initial emphasis on the optical design. Optical performance, as measured by photon throughput and minimization of polarization aberrations, will be critical to the success of the diagnostic. Consequently, the initial design work has been focused heavily on this area. In order meet the ITER MSE diagnostic design requirements, two approaches for the measurement are under consideration. The first is based on standard polarimeter techniques to measure the polarization of the emitted light, whereas the second measures the Stark splitting from which |B| can be inferred, where |B| is the magnitude of the total magnetic field. The base line design of the optical system is centered on the first approach. Emphasis in this case is placed on minimizing the polarization aberrations of the optical relay system. Motivation for the second method results from concern that the optical properties of the plasma-facing mirror, particularly its diattenuation and retardance, will degrade with plasma exposure. The second approach, while less sensitive to aberrations induced by plasma exposure effects, requires greater optical throughput in order to measure the complete Stark spectrum. We have developed an optimized optical design applicable to both measurement techniques. A summary of the design is presented and design issues are discussed.

[en] A system of customized spatial light modulators has been installed onto the front end of the laser system at the National Ignition Facility (NIF). The devices are capable of shaping the beam profile at a low-fluence relay plane upstream of the amplifier chain. Their primary function is to introduce 'blocker' obscurations at programmed locations within the beam profile. These obscurations are positioned to shadow small, isolated flaws on downstream optical components that might otherwise limit the system operating energy. The modulators were designed to enable a drop-in retrofit of each of the 48 existing Pre Amplifier Modules (PAMs) without compromising their original performance specifications. This was accomplished by use of transmissive Optically Addressable Light Valves (OALV) based on a Bismuth Silicon Oxide photoconductive layer in series with a twisted nematic liquid crystal (LC) layer. These Programmable Spatial Shaper packages in combination with a flaw inspection system and optic registration strategy have provided a robust approach for extending the operational lifetime of high fluence laser optics on NIF.

[en] We have developed a protein-enabled strategy to fabricate quantum dot (QD) nanoarrays where up to a 15-fold increase in surface-plasmon-enhanced fluorescence has been achieved. This approach permits a comprehensive control both laterally (via lithographically defined gold nanoarrays) and vertically (via the QD-metal distance) of the collectively behaving assemblies of QDs and gold nanoarrays by way of biomolecular recognition. Specifically, we demonstrated the spectral tuning of plasmon resonant metal nanoarrays and self-assembly of protein-functionalized QDs in a stepwise fashion with a concomitant incremental increase in separation from the metal surface through biotin-streptavidin spacer units.

[en] Germanium nanowires (GeNWs) have been synthesized by the thermal evaporation of Ge powder at 950 deg. C onto silicon wafer and ceramic (alumina) substrate using Au nanoparticles as a catalyst via a vapour-liquid-solid (VLS) process. The morphology, crystal structure and growth direction of the as-prepared GeNWs have been characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM). GeNWs are uniform with a diameter of ∼30 nm and lengths of tens of micrometres. High-resolution TEM shows that an individual GeNW is a single crystal with a diamond structure and a preferred growth along the <111> direction. Au nanoparticles are found at the tip of GeNWs indicating that the growth of GeNWs follows a VLS mechanism. The electronic and local structures of the as-prepared GeNWs have also been investigated by x-ray absorption fine structure spectroscopy (XAFS). The results and the implications will be discussed

[en] A simple, inexpensive, parallel approach has been developed for scalable large-area fabrication of two-dimensional (2D) periodic arrays of plasmon resonant structures. This method allows engineering of plasmon modes through precise tailoring of the structural parameters of metal nanostructures for reproducible Raman enhancement

[en] Mullite (2SiO₂·3Al₂O₃) nanoribbons, millimetres in length and with a high width-to-thickness ratio, were synthesized at temperatures as low as 1150 deg. C. This high ratio made it easy to fabricate a single nanoribbon sensor. The I-V relation of the sensor versus concentration of glucose was recorded with a pico-ammeter. The sensor shows good reproducibility and long-term stability. This single nanoribbon sensor may be used as an in situ monitor. The nanoribbons were also characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and x-ray photoemission spectroscopy