Dual-Site Lidar Observations and Satellite Data Analysis for Regional Cloud Characterization

Lidar data observed by two continuously operated portable automated lidar (PAL) systems and images from the visible and thermal infrared channels of the advanced very high resolution radiometer (AVHRR) sensor on board the noaa16 satellite are employed for the characterization of cloud heights and cloud types. The PAL systems are located in Chiba and Ichihara city areas, separated by approximately 10 km. Measurements from October 2003 to March 2005 reveal that monthly averages of cloud base height and cloud cover ratio show good agreement between the two sites. The characteristics of the vertical (Chiba) and slant (Ichihara) measurements are also discussed. The PAL data are used to adjust threshold values of a cloud-type classification method in split-window data of noaa16-AVHRR. Comparisons between the lidar signals and the cloud classification results from the concurrent AVHRR images show that the classification method can reasonably be applied to this mid-latitude case, although the split-window technique was originally developed for tropical clouds.     

Comparisons of EPR imaging and T1-weighted MRI for efficient imaging of nitroxyl contrast agents

The resolution and signal to noise ratio of EPR imaging and T(1)-weighted MRI were compared using an identical phantom. Several solutions of nitroxyl contrast agents with different EPR spectral shapes were tested. The feasibility of T(1)-weighted MRI to detect nitroxyl contrast agents was described. T(1)-weighted MRI can detect nitroxyl contrast agents with a complicated EPR spectrum easier and quicker; however, T(1)-weighted MRI has less quantitative ability especially for lipophilic nitroxyl contrast agents, because T(1)-relaxivity, i.e. accessibility to water, is affected by the hydrophilic/hydrophobic micro-environment of a nitroxyl contrast agent. The less quantitative ability of T(1)-weighted MRI may not be a disadvantage of redox imaging, which obtains reduction rate of a nitroxyl contrast. Therefore, T(1)-weighted MRI has a great advantage to check the pharmacokinetics of newly modified and/or designed nitroxyl contrast agents.     

Vertical electrical conduction in pentacene polycrystalline thin films mediated by Au-induced gap states at grain boundaries

Vertical electrical conduction in Au/(polycrystal-line pentacene)/Al diode structures and the influence of the kinetic energy of incident Au atoms on the conduction property have been comprehensively studied using current–voltage–temperature (I–V–T) measurements, ultraviolet photoelectron spectroscopy (UPS), atomic-force-microscope (AFM) current imaging, etc. In the I–V characteristics, a symmetrical ohmic current component appeared when a low voltage was applied, and a super-linear one appeared when a high positive voltage was applied to Au. The component in the high-forward-voltage region was concluded to be a thermionic emission of holes from Au with a 0.23-eV injection barrier, which is the normal hole conduction through the highest occupied molecular orbital of pentacene. On the other hand, the ohmic component was concluded to be a metal-like electron transport through high-density gap states at grain boundaries which were induced by the Au penetration into pentacene. UPS and I–V–T measurements clearly indicated the generation of the gap states and the enhancement of their density by the reduction of Au kinetic energy. For vertical-type devices with polycrystalline organic films, the ohmic conduction through the grain boundary will increase the leakage current. On the contrary, it possibly enhances the carrier injection in lateral-type transistors in the case of top-contact configuration.     

The effect of additional autopolyploidization in a slow growing cellulase hyperproducer of Trichoderma

M14-2 is a cellulase hyperproducer derived from Trichderma recesei QM 6a, but with a growth rate lower than that of the original strain. When M14-2 was autopolyploidized followed by haploidization and selection, the strain with both a higher cellulase productivity per mycelia and a higher growth rate could be obtained as M14-2B. This strain seemed to be constructed using gene sources amplified by additional autopolyploidization.     

Simplification of Space-Variant Parallel Logic Operations Using the Temporal Method

A time-domain encoding method (temporal method) for space-variant parallel logic operations, which can execute different operations in parallel, is proposed. The temporal method is based on temporal encoding of two input patterns, temporal gating of the coded pattern, and decoding by temporal addition of the gated patterns. The first feature of the proposed method is that parallel logic operations can be performed without complex pattern transformations. The second feature is that the logical output can be directly fed to succeeding systems without specific decoding. Therefore, the logic operation system can be constructed using conventional optics and existing spatial light modulators. In order to confirm these features, an optoelectronic experimental system is constructed and space-variant parallel logic operations are performed.     

Optical Characteristics of the Retroreflector in Space on the ADEOS Satellite in Orbit

Optical characteristics of the retroreflector in space (RIS) on the Advanced Earth Observing Satellite (ADEOS) in orbit were tested using a second harmonics Nd:YAG laser. The intensity of reflection from the RIS was analyzed with an intensified charge coupled device camera by comparing the image with those of stars. It was confirmed that the RIS in orbit is working properly as a retroreflector.     

Spatially localized states with size-dependent optical bistability

Experimental results of a new type of localized state generated in an optical system consisting of a liquid-crystal spatial light modulator with optical feedback are demonstrated. The localized state is triggered at a position that depends on the size of a control beam because its formation depends on the fraction of high-spatial-frequency components in the feedback light that passes through a low-cut spatial-frequency filter. This novel size-dependent switching property is useful for erasing individual target localized states.     

Reduction of Fringe Noise in Wavelength Modulation Spectroscopy Using a One-Dimensional Focal Plane Array

In wavelength modulation spectroscopy using diode lasers, detection limit of molecular absorption is often imposed by spurious fringe noises that arise from slight reflections among optical components. In an attempt to reduce this fringe effect, we propose and demonstrate the use of a one-dimensional focal plane array. With the help of a multiplexer, a single lock-in amplifier is employed to obtain multiple-channel signals from wavelength-modulated output of an array detector. It is found that the intensity change of the molecular absorption signal is nearly proportional to the transversal beam intensity distribution, whereas that of fringe noise is much less conspicuous. These features, as well as the phase difference among the channels, contribute to separate the signal and fringe noise components from the multiplexed spectra, leading to the overall improvement in the signal-to-noise ratio.