Development of neutron-monitor detector using liquid organic scintillator coupled with 6Li + ZnS(Ag) Sheet

A phoswitch-type detector has been developed for monitoring neutron doses in high-energy accelerator facilities. The detector is composed of a liquid organic scintillator (BC501A) coupled with ZnS(Ag) sheets doped with 6Li. The dose from neutrons with energies above 1 MeV is evaluated from the light output spectrum of the BC501A by applying the G-function, which relates the spectrum to the neutron dose directly. The dose from lower energy neutrons, on the other hand, is estimated from the number of scintillations emitted from the ZnS(Ag) sheets. Characteristics of the phoswitch-type detector were studied experimentally in some neutron fields. It was found from the experiments that the detector has an excellent property of pulse-shape discrimination between the scintillations of BC501A and the ZnS(Ag) sheets. The experimental results also indicate that the detector is capable of reproducing doses from thermal neutrons as well as neutrons with energies from one to several tens of megaelectronvolts (MeV).     

Identification of novel nonmethylene-interrupted fatty acids, 7E,13E-20∶2, 7E,13E,17Z-20∶3, 9E,15E,19Z-22∶3, and 4Z,9E,15E,19Z-22∶4, in ophiuroidea (Brittle star) lipids

Fatty acids of Ophiuroidea (brittle star) Ophiura sarsi have been investigated by gas-liquid chromatography (GLC). About 2–13% of four unidentified fatty acids were found in total fatty acids from a sample caught at a depth of 1,100 m. Structural analyses were undertaken after partial hydrogenation of their concentrates with hydrazine hydrate and subsequent isolation of the monoenoate products by argentation thin-layer chromatography. The structures of the unidentified fatty acids were determined as 7E,13E-eicosadienoic (20∶2), 7E,13E,17Z-eicosatrienoic (20∶3), 9E,15E,19Z-docosatrienoic (22∶3), and 4Z,9E,15E,19Z-docosatetraenoic (22∶4) acids by gas chromatography-mass spectrometry of dimethyl disulfide adducts and GLC of the monoenoates on a polar column. These fatty acids belong to a family of nonmethylene-interrupted (NMI) polyunsaturated fatty acids frequently observed in marine invertebrates and conifer seeds. As far as the authors know, however, these NMI fatty acid types with mixed geometry of ethylenic bonds have not been reported previously.     

Functional monomers and polymers, 74. Physico-chemical study on the chitosan-iodine complexes

The adsorption of iodine on chitosan was studied by physico-chemical methods. The scanning electron micrograph measurements of chitosan-iodine adducts showed that iodine molecules were adsorbed uniformly on the chitosan film when the film was treated with aqueous iodine-potassium iodide solution. The thermogravimetric analysis of the adducts revealed that the loss in weight began at about 190°C, and that iodine molecules were thus well-complexed with chitosan. It was also found that the IR spectra of the chitosan films showed the amide I and amide II bands shifted to lower frequencies due to the iodine adsorption. The X-ray diffractometry of these adducts was further carried out, and it was found that the iodine adsorbed chitosan showed no crystalline pattern, different from that of the original chitosan which showed crystallinity in some extent. The chitosan recovered after desorbing iodine by immersion in aqueous sodium thiosulfate solution was amorphous.     

Reinvestigation of positional distribution of fatty acids in docosahexaenoic acid-rich fish oil triacyl-sn-glycerols

Positional distribution of fatty acids in triacyl-sn-glycerols of docosahexaenoic acid (DHA)-rich tuna orbital and bonito head oils has been reanalyzed by a method based on chromatographic separation of isomeric and enantiomeric monoacyl-sn-glycerol (MAG) derivatives. When boric acid thinlayer chromatography (TLC) was used for separation of 1(3)- and 2-MAG analytical intermediates, the stereospecific analysis showed the preferential association of DHA to the sn-2 position followed by the sn-3 position. This distribution pattern differed from that obtained by silicic acid LTC of their bis-3,5-dinitrophenylurethane (DNPU) derivatives. Reversed-phase high-performance liquid chromatography elution profiles of 1(3)- and 2-MAG intermediates revealed that 1(3)- and 2-MAG made up of both short- and long-chain lengths cannot be clearly resolved by TLC after preparation of the DNPU derivatives. The 1(3)- and 2-MAG must be resolved by boric acid TLC prior to derivatization.     

Preparation of nanocomposite for optical application using ZnTe nanoparticles and a zero-birefringence polymer

Surface-modified ZnTe nanoparticles were mixed in a zero-birefringence polymer matrix. Transmission electron microscopy images revealed that aggregates of ZnTe nanoparticles with a diameter of ∼20 nm were uniformly dispersed in the polymer. The transmittance of ZnTe nanocomposites rapidly decreased at wavelengths shorter than the critical wavelength corresponding to the band gap of ZnTe nanoparticles, an effect which became significant as the volume fraction of particles increased. In this way, the optical characteristic of ZnTe nanoparticles was added to the polymer. The intrinsic zero-birefringence was confirmed in the heat-drawn ZnTe nanocomposites. As the ZnTe nanocomposites were left in air, a lowering of transmittance was observed. This was due to the oxidation of Zn and the resultant deposition of Te in the ZnTe nanocomposite, as the light absorption of Te is significant. The formation of oxygen non-permeable SiO₂ films onto the ZnTe nanocomposite by the sol-gel method was useful in preventing oxidation so that the decrement of transmittance decreased from 47.2% to 14.9% at 530 nm near the ZnTe band gap.     

Preparation of TiO2 hollow microparticles by spraying water droplets into an organic solution of titanium tetraisopropoxide

Hollow, spherical TiO₂ microparticles several tens of micrometers in diameter were prepared by spraying water into an organic phase containing titanium tetraisopropoxide (TTIP) as a titanium source. The rapid hydrolysis of TTIP at the water-oil interface resulted in the formation of a TiO₂ shell covering the water droplet. Hexane and cyclohexane were better solvents than isopropanol for fabricating hollow spherical microparticles, suggesting the importance of immiscibility of the solvent with water in this synthesis method. The average particle size increased as the distance from the nozzle to the surface of the TTIP solution was increased. The shell thickness was reduced by the addition of ethanol to the sprayed water droplet. These results demonstrate the controllability of the structure of TiO₂ hollow microparticles, including the diameter and the shell thickness.     

A novel deep etching technology for Si and quartz materials

A disadvantage of ICP type plasma etching method compared with CCP one is low selectivity to photo resist. So a novel etching method was developed to obtain high selectivity to photo resist by incorporating a sputtering method, in which a target was placed on the opposite side of the substrate. Satisfactory results were obtained for a continuous gas feeding treatment and also for a gas modulating treatment.     

Evaluation of the shape and size of 3D cracks using microwaves

A method to evaluate the shape and size of a small 3D crack by microwaves was demonstrated. By considering the interference phenomenon occurring in the case of 3D cracks, a parameter reflecting microwave interference effect, which is a function of the position of the sensor in the direction of the crack length, was introduced into the usual dual frequency evaluation-equation. From the modified dual frequency equation, a new component named interference waveform, which is based on the amplitude of the reflection coefficient measured at two different frequencies, was obtained. On the other hand, based on the interference model, a corresponding interference waveform, which can be calculated from the assumed shape and size of a 3D crack, was also introduced. By comparing these two interference waveforms, the evaluation of the shape and size of the 3D crack were carried out. Four 3D fatigue cracks having different shape and size were treated. The shape and size of all the cracks were estimated well by using the proposed method.     

The technologies of in‐cell optical touch panel with novel input functions

Abstract— The technologies behind an in‐cell optical touch‐panel LCD with novel input functions will be described. By improving both the optical and electrical signal‐to‐noise ratio (SNR), a touch‐panel operation robust to ambient conditions can be achieved with a low‐power consumption suitable for integration into mobile products. The high SNR also enables a range of novel input functions making the in‐cell optical touch panel a promising platform for the next‐generation of user interface.     

Intravital dual-colored visualization of colorectal liver metastasis in living mice using two photon laser scanning microscopy

A major challenge of cancer biology is to visualize the dynamics of the metastatic process in secondary organs at high optical resolution in vivo real-time. Here, we presented intravital, dual-colored imaging of liver metastasis formation from a single cancer cell to metastatic colonies in the living liver of living mice using two photon laser scanning microscopy (TPLSM). Red fluorescent protein expressing murine (SL4) or human (HT29) colorectal cancer cell lines were inoculated to the spleen of green fluorescent protein expressing mice. Intravital TPLSM was performed by exteriorizing and fixing the liver lobe of living mice. This was repeated several times for the long-term imaging of the same mouse. Viable cancer cells in the living liver of living mice were visualized intravitally at a magnification of over 600×. Single cancer cells were arrested within hepatic sinusoids 2 h after injection. Platelet aggregation surrounding a cancer cell was observed, indicating a phenomenon of tumor-cell induced platelet aggregation. Cancer cells were extravasated from hepatic sinusoids to the space of Disse. Protrusions of Kupffer cells surrounding a cancer cell were observed, indicating that Kupffer cells appear to phagocytose cancer cells. SL4 cells formed liver metastatic colonies with extensive stromal reaction. Liver metastases by HT29 cells were observed as a cluster of micrometastatic nodules. High-resolution, dual-colored, real-time visualization of cancer metastasis using intravital TLPSM can help to understand spatiotemporal tumor-host interactions during metastatic processes in the living organs of living animals.