OCEANcode: The complete set of algorithms and models for the level_2 processing of European CZCS historical data

A complete set of algorithms and models for the level_2 processing of the European CZCS historical data was integrated in the OCEANcode software package. The OCEANcode allows the calibration of the sensor-recorded signal taking into account the instrument sensitivity loss; the correction of the calibrated signal for atmospheric contamination and derive sub-surface reflectances; and then the estimation of the concentration of water constituents. The atmospheric correction is performed on the basis of a reflectance-model-based algorithm. The Rayleigh correction is applied consistently for all water pixels, using a multiple scattering approach, and introducing atmospheric pressure and Ozone concentration data in the computation. The marine aerosol correction uses a pixel-by-pixel iterative procedure, allowing successive estimates of both the marine reflectance in the red spectral region (670nm) and the Angstrom exponent, which links simple wavelengths ratios to reflectance ratios. For case 1 waters, the optical properties of which are essentially dominated by planktonic pigments, the interrelations between marine reflectances and reflectance ratios at various wavelengths are derived from modelled calculations. For identified case 2 waters, where water constituents other than planktonic pigments (i.e. dissolved organics and suspended sediments) dominate the water optical properties, the evaluation of marine reflectances is approximated by means of interpolated Angstrom exponent values computed over case 1 water pixels and of empirical relationships derived from in situ measurements. The computation of chlorophyll-like pigments is performed with algorithms based on blue/green (443-550nm) reflectance ratios, for lower pigment concentration, or on green/green (520-550nm) reflectance ratios, for higher pigment concentration. As for the case of atmospheric corrections, the inter-relations between pigment concentration and reflectance ratios are model-derived for case 1 waters, and empirically determined for case 2 waters.     

Symbiosis of Silica Biomorphs and Magnetite Mesocrystals

Silica biomorphs are extraordinary inorganic superstructures formed via autocatalytic co‐precipitation and bottom‐up self‐assembly of alkaline‐earth carbonates and silica. However, they show no inherent functionality except for their striking textural motifs and curved morphologies. This work presents strategies to magnetize silica biomorphs, thus creating thermally stable ceramic microswimmers with unique elaborate shapes. This is achieved by growing super paramagnetic magnetite mesocrystals on and around the complex curved surfaces of biomorphs, while keeping their morphology and maintaining mesocrystal integrity. Selective mesocrystal formation on certain parts of the substrates is induced by chemical modification of the biomorph surface, increasing the loading of magnetite on the silica–carbonate structures and, in suitable cases, rendering them able to respond to external magnetic fields and move as microswimmer entities. In this way, the complex ultrastructure of silica biomorphs is successfully used as a template for functional ceramics. Furthermore, selective dissolution of the carbonate core from the biomorphs leads to hollow magnetic structures that could be filled with actives, thus serving as microcarriers with considerable loading capacity.     

Optical receiver IC for CD/DVD/blue-laser application

In this paper, an optoelectronic receiver IC for CD, DVD, and Blue-Laser optical data storage applications is presented. The IC was developed in a 0.5-/spl mu/m BiCMOS technology with integrated PIN photodiodes. It includes a new architecture of high-speed and low-noise variable gain transimpedance amplifiers witch current preamplifier input. The amplifier transimpedance gain is programmable over a gain range of 130 /spl Omega/ to 270 k/spl Omega/ by a serial interface. The amplifier small-signal bandwidth is 260 MHz for the highest gain, which gives a gain-bandwidth product of 70 THz/spl Omega/ and a sensitivity improvement by a factor of 2 compared to published OEICs. The amplifiers support a special write/clip mode which realizes a nonlinear gain reduction for high input signals. The output voltage buffers are 130-/spl Omega/ impedance matched for optimized data transmission over a flex cable. The impedance is generated by active-impedance synthesis to increase the output dynamic range.     

Magnetic Nanoparticle Chains in Gelatin Ferrogels: Bioinspiration from Magnetotactic Bacteria

Inspired by chains of ferrimagnetic nanocrystals (NCs) in magnetotactic bacteria (MTB), the synthesis and detailed characterization of ferrimagnetic magnetite NC chain‐like assemblies is reported. An easy green synthesis route in a thermoreversible gelatin hydrogel matrix is used. The structure of these magnetite chains prepared with and without gelatin is characterized by means of transmission electron microscopy, including electron tomography (ET). These structures indeed bear resemblance to the magnetite assemblies found in MTB, known for their mechanical flexibility and outstanding magnetic properties and known to crystallographically align their magnetite NCs along the strongest <111> magnetization easy axis. Using electron holography (EH) and angular dependent magnetic measurements, the magnetic interaction between the NCs and the generation of a magnetically anisotropic material can be shown. The electro‐ and magnetostatic modeling demonstrates that in order to precisely determine the magnetization (by means of EH) inside chain‐like NCs assemblies, their exact shape, arrangement and stray‐fields have to be considered (ideally obtained using ET).     

Amorphous Silicon Thin-Film Transistor Backplanes Deposited at 200 °C on Clear Plastic for Lamination to Electrophoretic Displays

The transition of thin-film transistor (TFT) backplanes from rigid plate glass to flexible substrates requires the development of a generic TFT backplane technology on a clear plastic substrate. To be sufficiently stable under bias stress, amorphous-silicon (a-Si:H) TFTs must be deposited at elevated temperatures, therefore the substrate must withstand high temperatures. We fabricated a-Si:H TFT backplanes on a clear plastic substrate at 200degC. The measured stability of the TFTs under gate bias stress was superior to TFTs fabricated at 150degC. The substrate was dimensionally stable within the measurement resolution of 1, allowing for well-aligned 8 times 8 and 32 times 32 arrays of pixels. The operation of the backplane is demonstrated with an electrophoretic display. This result is a step toward the drop-in replacement of glass substrates by plastic foil.     

Evolution of the snow area index of the subarctic snowpack in central Alaska over a whole season. consequences for the air to snow transfer of pollutants

The detailed physical characteristics of the subarctic snowpack must be known to quantify the exchange of adsorbed pollutants between the atmosphere and the snow cover. For the first time, the combined evolutions of specific surface area (SSA), snow stratigraphy, temperature, and density were monitored throughout winter in central Alaska. We define the snow area index (SAI) as the vertically integrated surface area of snow crystals, and this variable is used to quantify pollutants' adsorption. Intense metamorphism generated by strong temperature gradients formed a thick depth hoar layer with low SSA (90 cm(2) g-1) and density (200 kg m(-3)), resulting in a low SAI. After snowpack buildup in autumn, the winter SAI remained around 1000 m(2)/m(2) of ground, much lower than the SAI of the Arctic snowpack, 2500 m(2) m-(2). With the example of PCBs 28 and 180, we calculate that the subarctic snowpack is a smaller reservoir of adsorbed pollutants than the Arctic snowpack and less efficiently transfers adsorbed pollutants from the atmosphere to ecosystems. The difference is greater for the more volatile PCB 28. With climate change, snowpack structure will be modified, and the snowpack's ability to transfer adsorbed pollutants from the atmosphere to ecosystems may be reduced, especially for the more volatile pollutants.