Junichi Kita

DC superconducting quantum interference device of YBa2Cu3O7-x step-edge junctions

DC superconducting quantum interference devices (DC-SQUIDs) are made of YBa2Cu3O7-x(YBCO) thin films by conventional photolithography and argon ion milling. The YBCO thin films are prepared on magnesia substrates with step edges by the rf magnetron sputtering method. The step-edge junctions for the SQUIDs exhibit clear DC and AC Josephson effects. The SQUIDs respond well to change of magnetic flux and have a white flux noise at 51.4 K of 8.1×10-5 Φ0/Hz1/2 at 1 Hz, 5.8×10-5 Φ0/Hz1/2 at 10 Hz and a noise increase at a low-frequency range of less than 10 Hz.

Combination of real-value smell and metaphor expression aids yeast detection.

Background Smell provides important information about the quality of food and drink. Most well-known for their expertise in wine tasting, sommeliers sniff out the aroma of wine and describe them using beautiful metaphors. In contrast, electronic noses, devices that mimic our olfactory recognition system, also detect smells using their sensors but describe them using electronic signals. These devices have been used to judge the freshness of food or detect the presence of pathogenic microorganisms. However, unlike information from gas chromatography, it is difficult to compare odour information collected by these devices because they are made for smelling specific smells and their data are relative intensities. Methodology Here, we demonstrate the use of an absolute-value description method using known smell metaphors, and early detection of yeast using the method. Conclusions This technique may help distinguishing microbial-contamination of food products earlier, or improvement of the food-product qualities.

The IR modulator utilizing light scattering effect with ferroelectric liquid crystal for gas analysis

abstractExperimental infrared modulator elements have been fabricated utilizing the transient light scattering effect of ferroelectric liquid crystal with asymmetric waveform voltage drive. The new elements perform 80% modulation degrees at the 632.8nm. We have also achieved 30% modulation degrees in the 4 to 5µ m region where the strongest CO2 absorption bands exist. A new type of analyzer which monitors ambient air quality has been developed. This analyzer uses non-dispersive infrared absorption method and composes of a double-beam, a single detector and a pair of liquid crystal light modulator as the IR chopper. The detection has achieved 10ppm noise equivalent concentration.

Advanced in Development IR Modulators of Ferroelectric Liquid Crystals Utilizing Transient Light Scattering Effects

Abstract The highly efficient IR-modulation has been achieved using LC electro-optic elements. Experimental infrared modulator elements have been fabricated and demonstrated utilizing the transient light scattering effect of ferroelectric liquid crystal with asymmetric waveform voltage drive. The new elements performed 80%, 50%, 40% and 25% modulation degree in the 632.8nm, 2, 3-5 and 8-12 μm region. And we observed micro domain structure under the scattering state by a polarizing microscope to understand the mechanism of the domain switching. In addition, we evaluated properties of the scattering angular and temperature dependence quite important for the design of optics for the application in the infrared range.

Quantification of Odor including Masking effect and Odor Word Expression

The objective portion of odor sense is studied. The suitable expression of odor is important to clarify the objective region of odor. The deviation odor expression like QDA method is practical for ordinary odor explanations. By using the easy sensory test device consisted of auto-dilution gas-tight syringe, the expression of deviation odor to the different center odor is tested. Then the nature of deviation odor may be constant against different center odor. Finally masking effect is quantified by using suitable odor expression and easy sensory device.

A light chopper for infrared detection utilizing ferroelectric liquid crystal

The transient light scattering mode effect due to polarization inversion of ferroelectric liquid crystal was used in the experimental design of a light chopper for infrared detection. In order to understand the light scattering effect, the relationship between the driving conditions and pulse response speed of domain switching was analyzed. Light modulation was optimized by adjusting the duty cycle in rectangular wave driving. This method made it possible to improve the light scattering response due to electric field inversion, resulting in high-efficiency light modulation. It was found that the improvement of light scattering response occurred because the recovery speed from the scattering state to the nonscattering state was accelerated by the electric field inversion. By observing the generation-growth-extinction process of scattering objects, the relationship between the change in the liquid crystal structure and light scattering was obtained. The wavelength dependence of the light modulation-voltage characteristic and the temperature dependence of the field of view and the degree of modulation were elucidated.