Search

Timely and nondestructive monitoring of leaf area index (LAI) using remote sensing techniques is crucial for precise and efficient management of crops. In this paper, a new spectral index (SI) for estimating LAI of winter wheat (Triticum aestivum L.) is proposed on the basis of field hyperspectral measurements. A simple index based on the empirical relationships between LAIs and SIs of all available two-waveband combinations from hyperspectral data is developed by considering the difference between reflectance values at 760 and 739 nm (DSIR760–R739 = R760 – R739). Among published and newly developed SIs, DSIR760–R739 exhibited a significant and strong linear relationship with LAI and showed outstanding performance in LAI assessments. The permissible bandwidths for broad-band DSIR760–R739 investigated using simulated reflectance were 5 nm for both 760 and 739 nm center wavelengths. The results indicate that the linear regression model based on the narrow-band and broad-band DSIR760–R739 is a simple but accurate method for timely and nondestructive monitoring of LAI.

In order to validate the availability of rbNDVI (red and blue Normalized Difference Vegetation Index) for chlorophyll estimation, we conducted estimation of leaf chlorophyll concentration at heading to anthesis stage which highly correlates with grain protein concentration using ground-based and aerial hyperspectral data at agriculture fields in Gifu prefecture. In the ground measurement, rbNDVI showed high correlation (γ2=0.731) with leaf chlorophyll concentration compared to widely used NDVI (Normalized Difference Vegetation Index; γ2=0.231) and TCARI/OSAVI (Transformed Chlorophyll Absorption in Reflectance Index/Optimized Soil-Adjusted Vegetation Index; γ2=0.333), and the estimate equation is able to applied in the different study site (Root Mean Square Error: RMSE=2.54μg cm-2) . In the aerial scale, rbNDVI also showed good result in chlorophyll estimation (2006: γ2=0.427, 2007: γ2=0.447, RMSE=4.18μg cm-2) using atmospheric correction of 6S code and reflectance matching method. According to these results, the spatial distribution map of chlorophyll concentration was created. The spatial distribution map of chlorophyll concentration using rbNDVI may provide the useful information for additional fertilization aim to the improvement of the grain protein concentration over the large area.

Abrasive properties of cocoon shaped silica particles fabricated by a sol–gel method have been studied. Since silicon wafers are polished with slurry by the mechanism of Chemical Mechanical Polishing, polishing rates may depend on various chemical and mechanical factors, such as particle concentration in slurry, slurry pH and kinds of basic compounds for controlling the slurry pH.

Erbium-doped silica-based glass for optical amplifiers is fabricated from silica powders by a compression-forming method using a cold isostatic pressing (CIP) technique. Silica powders are prepared from slurry containing fumed silica with submicrometer diameter and erbium source by granulating using a spray drier. The average diameter of the granulated powders is 50 μ and about 150 times as large as that of the fumed silica. The silica powders are packed in a rubber mold and are compressed by CIP. It is found from thermal analysis that the compressed powders can be degreased PVP at 600°C. After degreasing at 600°C, the compressed powders are sintered by a sintering process using an electric furnace or a gas burner. The compressed powders can be vitrified by using not the electric furnace but the gas burner. The existence of Er ions in the glass sintered by the gas burner is confirmed from UV-VIS spectra.

Photosensitive organic-titania hybrid materials have been prepared from metal alkoxides and various organic ester compounds with \(C{=}C\) double bonds. The refractive index of the film increases with the decrease of the concentration of the organic ester compound, and the highest refractive index of 1.62 is obtained when 2-hydroxymethyl acrylate (HOA) is used as the organic ester and the molar ratio of HOA to Ti is 0.5. The material with the highest refractive index is exposed to femtosecond pulse using the multi-beam laser interference technique. After laser irradiation, the irradiated parts of the material are photopolymerized and periodic structures can be obtained by development of the unirradiated parts. In the case of laser irradiation of 120 μ J total energy for 5 min, the periodic structure obtained corresponds to 2D photonic crystal structure which is composed of two parts; the material with the highest refractive index and the air.

In order to produce an excellent abrasive, a fabrication method for cocoon shaped silica particles has been studied. The particles are prepared from TMOS, water, ammonia and methanol by a sol–gel method. The method is to add the methanol solution of TMOS at a constant supply rate to a mixture of water, ammonia and methanol. Effects of various reaction conditions such as temperatures, supply rates of TMOS, and amounts of TMOS are studied on the diameter and shape of the particles. The diameter and shape are resulted in depending strongly on temperatures. High temperature makes particles with the high aspect ratio and the small diameter. And the mechanism of forming the cocoon shaped particle is also discussed. It is concluded that the primary particles are generated at the beginning stage of reaction and two of them become the cocoon shaped particle. For the polishing efficiency, particles have high polishing efficiency with the diameter between 40 nm and 210 nm. As a result, best diameter of particles for abrasive is 40–100 nm with respect to polishing efficiency and surface finish.

Hybrid titania gel films are prepared from titanium butoxide and vinylpyrrolidone (VP). When the gel film is exposed to UV light, the CC double bond of VP in the film polymerizes and the solubility of the irradiated film decreases in HCl aqueous solution. The difference of the solubility between the irradiated and unirradiated parts makes fine patterning on the hybrid titania film whose refractive index is in the range between 1.8 and 2.1.

Fiber-optic carbon dioxide sensors with a dip-coated sol–gel film containing indicator dye of thymol blue are prepared and characterized. The sensitive film has both organic and inorganic parts with good gas permeability. The difference between attenuations in N 2 gas and in CO 2 /N 2 mixture gas increases with the increase in the CO 2 concentration in the 0.55–0.7 μm range. The attenuation difference increases linearly with the increase in the logalism of CO 2 concentration, although there is no difference under 0.1% CO 2 gas concentration. The sensitivity of the sensor increases with the increase in the dye concentration. The relative humidity and the film composition have an important effect on the attenuation difference.

Photosensitive hybrid titania films have been prepared from titanium butoxide modified with β-diketone and methacrylic acid. When this film is exposed to UV light, the β-diketonato chelate from the alkoxide and β-diketone is dissociated, and the unsaturated hydrocarbon of methacrylic acid is polymerized. These structural changes in the gel film have led to a difference between the solubility of irradiated and unirradiated parts in the film; therefore, a fine patternable hybrid titania film has been fabricated.

We report on a fabrication of photonic crystal structures in organic-inorganic hybrid films by a laser interference technique. Films containing the methacrylic group, which is photopolymerable by an adequate laser light, are prepared using a sol-gel technique from a mixture of organosilicate alkoxide and zirconium alkoxide modified by methacrylic acid. For the photopolymerization, the coated films on glass substrate are exposed to the interference light which is arranged with a square lattice in about 1 μm spacing. From microscopic images of microstructures produced by the photopolymerization, the influence of changes in conditions such as pre-bake temperature, photoinitiator and irradiation energy (laser power and duration time) on periodic structure is investigated. Adjusting the conditions, 2D and 3D photonic crystal structures with the micrometer-order period are formed in organo-silicate-zirconate hybrid materials.

Channel waveguides are produced from organic-inorganic hybrid materials derived by the sol-gel process. The organic-inorganic hybrid film containing photosensitive C=C bonds changes by the UV irradiation. The solubility difference between irradiated and unirradiated parts can easily give a core with about 8μm square. The refractive indexes of the core and cladding layers are measured and the single mode waveguide is designed for the materials.

A new fiber-optic ammonia sensor utilizing rectangular-cladding eccentric-core fiber and a sensitive film containing an indicator dye is demonstrated. The sensitive film is a SiO2-GeO2 gel film including an indicator dye of bromocresol purple or bromocresol green, which is dip-coated by a sol-gel technique. The attenuation of this sensor changes depending on the concentration of ammonia at the wavelength range of 500–700 nm. This sensor can detect several ppm of gaseous ammonia. Various factors determining the sensitivity to detect the ammonia gas and time response of the sensor are also studied.

Fabrication of optical fibers with a polygonal cladding was studied. The glass preform for that fiber was made by consolidation of a soot preform with a polygonal cladding that results from cutting a round hybridized soot preform produced by the direct cold isostatic pressing (CIP) process. That optical fiber was drawn at a temperature as low as 1850°C from a glass preform with a polygonal cladding. Fibers with a square cladding, a regular octagonal cladding, and a rectangular cladding were realized by the method mentioned above. The transmission loss of a square fiber measured 0.69 dB/km at 1.3 μm. A fiber with a rectangular cladding and an eccentric core was also made advantageously by this method.

Novel birefringent single-mode fibers are fabricated with a vacant hole on either side of the central elliptical core, referred to as side-hole fiber, and their intrinsic and tension-induced modal birefringences are measured to know their characteristic properties for the purpose of making a strain sensor. Five sampled side-hole fibers are prepared for measurements. The sensitivity of the strain sensor is primarily determined by two parameters, tension-induced and intrinsic modal birefringences. Tension-induced modal birefringence is controllable by optimal arrangement of the size and location of the side-holes in the cross-section of the fiber. A sensitivity diagram for designating and fabricating side-hole fibers is presented.

The fabrication and characterization of side-hole single-mode optical fibers have been studied. Controlling the internal pressure of side holes in a preform made possible the fabrication of side-hole fibers with various core ellipticities and with a circular core. The relationship between theVcand the core ellipticity for side-hole fibers showed good agreement with that calculated for elliptical core fibers without side holes. The best transmission loss of the side-hole fibers with a circular core was 0.9 dB/km. A large birefringence of 2.3 × 10−4was also obtained in side-hole fibers with elliptical cores.

A new hybridized process for preparing optical fibers has been developed. The process consists of overcladding a VAD-derived core rod with commercial silica powder by cold isostatic pressing (CIP) technique. Single-mode optical fibers were fabricated by the process which used the core rod having a ratio of core to cladding radius of 3 and silica powder of average particle diameter of 10μm. The losses were 0.36dB/km at 1.3μm and 0.23dB/km at 1.55μm. The points for the process are following; (1) Silica powder was granulated by spray dryer from slurry containing poly-vinyl-alcohol (PVA) to be packed uniformly into a rubber mold for CIP forming. (2) To prevent the core rod from breaking in the compression, a rubber mold with a structure in which both ends of the core rod were pressed by hydrostatic pressure was used. This CIP process provided the hybridized soot preform which consisted of the core rod and a porous body around it from silica powder in one step. (3) It was very important that 10μm silica powder was used because it was easy to purify into high-purity glass. (4) To remove PVA which was added in granulating, heat treatment was carried out at 500°C in an atmosphere of dry air. The heat-treated porous body containing 25ppm carbon was consolidated into the overcladding glass for low-loss optical fibers. Further, a relation between the pore diameter and purification of the porous body was studied. As a result, pores with more than 0.2μm diameter were presumed to be required for making high-purity glass by chlorine purification.

A CIP hybridized process for fabrication of a single-mode optical fiber with a small core eccentricity error has been studied. As a result, a process for fabrication of an optical fiber with a core eccentricity error of less than 0.3μm has been developed. In this study, we also clarified the following. (1) A hybridized soot preform with an outer diameter noncircularity of less than 0.4% was prepared by packing granular silica particles with a high packing density into a rubber mold with a thick wall. (2) A soot preform with a noncircularity of less than 0.06% and an outer diameter fluctuation of less than 0.11mm was made by means of a grinding treatment in which the outer surface of the soot preform was ground around a core rod. (3) A single-mode optical fiber with a core eccentricity error of less than 0.3μm was also fabricated from the soot preform ground above.

A new hybridized process for preparing optical fibers has been developed. The process consists of overcladding a VAD-derived core rod with commercial silica powder by extrusion shaping technique. The single-mode optical fiber was fabricated by the process which used a core rod having a ratio of core/cladding diameter of 1/3.15 and silica powder of average particle diameter of 10μm. The transmission losses were 0.40dB/km at 1.3μm and 0.26dB/km at 1.55μm. In this study, we also clarified as follows: (1) The lamination which occurs at extrusion can disappear by using an extension cylinder with bolts. (2) Bubbles in the optical fiber preform do not occur by using plastic material in which surface active agent is added in the mixture consisting of silica powder, water and methyl-cellulose. (3) The soot preform which consists of a core rod and a porous body around it can be extruded by using an extruder which is reconstructed a commercially available one for hybridized extrusion.

A very rare case of adenomyoma of the common hepatic duct is described. A 54-year-old woman was admitted with impending obstructive jaundice secondary to adenomyoma of the common hepatic duct. Our impression, formulated from her clinical presentation, endoscopic investigations, and biochemical and radiological findings, was a cancer of the proximal common hepatic duct. The patient was treated successfully by combination surgical resection and hepaticojejunostomy. Despite our obtaining an intraoperative frozen section, final histological examination was required to confirm the diagnosis. The patient remains well 16 months postoperatively. A survey of the world literature revealed that this is the second report of adenomyoma occurring in the common hepatic duct.

A case of carcinosarcoma arising from the intraepithelial spreading area of esophageal squamous cell carcinoma (SCC) is reported herein. A 64-year-old man was referred to our hospital for investigation of a sore throat and dysphagia. An endoscopic examination revealed a 2. 5-cm polypoid mass in the mid-esophagus. Esophagograms taken 1 month prior to consultation by our hospital and just before surgery revealed marked change within a period of less than 2 months from a 2-cm sessile elevated mass to a 4-cm polypoid mass with a lobular appearance. The resected specimen contained two lesions in the esophagus. The larger one measured 4.0 x 2.0 x 2.0 cm and had a pedunculated polypoid shape, while the smaller one, measuring 1 cm in diameter, was a plateau-type elevated lesion located 3 cm distal from the larger mass. Histologically, the distal smaller lesion was diagnosed as primary SCC associated with a high frequency of intraepithelial spread, while the larger polypoid mass was composed of spindle-shaped sarcomatous cells, arising from the intraepithelial spread of SCC. To our knowledge, this is the only reported case of esophageal carcinosarcoma arising from an area of intraepithelial spread of SCC that showed such surprisingly rapid growth.

Optical fibers, being already promised as an effective sensing media, have a wider range of capabilities as optical sensors or optical devices by giving them special shapes. Devising special shapes is surely effective in controlling the polarization planes or in enlarging the outer cladding component of the evanescent fields, so that such advantages as new sensing capability or sensing sensitivity may be realized which are not available using ordinary optical fibers[1-12]. We have been successful in developing fabrication technologies for various types of special shape fibers(SSFs); and thus have been engaged in the development of new applications based on the SSFs. The SSFs, successfully developed, may be classified into three groups according to their structure: 1) fibers with special shape cladding like D-shape fiber[1], an earlier developed SSF; 2) fibers with special shape core, and 3) fibers with special shape of both cladding and core. Among them, four typical SSFs shown in Figure 1 will be covered in Section 2 along with their applications: an eccentric core fiber, a rectangular eccentric core fiber, a twin hole fiber, and a square fiber.

The ZnII phosphate complex, [ZnII(bnp)(tpa)](ClO4) (2) was structurally characterized. The hydrolysis reaction of phosphate ester in 2 was promoted under acidic aqueous media efficiently. The relevancy of this system to P1 nuclease, which has a low optimal pH condition, is also discussed.

The influence of electrode materials on the current vs. voltage characteristics of limiting-current-type zirconia cells has been investigated systematically. The cells have one or two pairs of electrodes consisting of Pt, Pd, Au, or Ag, and a cover with a pinhole, which serves to limit gas diffusion and, therefore, the electrical current of the cells. The limiting current was found to depend definitely on the catalytic activity of the electrodes for the oxidation reaction of hydrocarbon gases in oxygen and hydrocarbon--containing gases. The results were applied to improve the sensitivity of limiting-current hydrocarbon sensors. The highest sensitivity was attained for the following combination of electrodes: Pt and Ag inner electrodes and a Au outer electrode in two-inner-electrode sensors. A preliminary examination has also been made on a three-inner-electrode sensor.

Polarisation modulators with either square fibres or regular octagonal fibres have been fabricated for the first time. The frequency responses of the modulators were measured and compared to a polarisation modulator with a round fibre. The results showed that the new modulators have a much higher modulation efficiency and a greater number of active frequency ranges than do round-fibre modulators.

A new hybridised process for singlemode optical fibres has been developed. The process consists of overcladding a VAD-derived core rod with a tubular porous body made from commercial silica powder using a compression forming technique. Optical fibres consisting of 95% powder-derived and 5% VAD-derived silica are fabricated with losses of 0.392 dB/km at 1.3 /spl mu/m and 0.275 dB/km at 1.55 /spl mu/m.

A hybrid optical computing system having a parallel optical logic gate and electronic feedback circuits is proposed. With this system, various repeated parallel computations can be performed.

A method for synthesizing pyromellitic acid by liquid phase air oxidation of durene was studied. The air oxidation of durene was carried out in glacial acetic acid, using Co(OAc)2•4H2O, Mn(OAc)2•4H2O and KBr as catalysts, at the reaction temperature of 205-210°C and the total pressure of 20kg/cm2•G. The solid materials obtained by the oxidation were recrystallized into pyromellitic acid in an aqueous solution of nitric acid. The following results were obtained.(1) Cobalt and manganese used as catalysts were found, after oxidation, as salts in the solid material and had to be removed by treating with mineral acid to obtain pyromellitic acid.(2) The oxidation of durene into pyromellitic acid required a far larger amount of catalysts than the oxidation of p-xylene into terephthalic acid.(3) In the presence of heavy metal component, bromine component in the catalysts accelerated the latter stage of the oxidation, thereby promoting the formation of pyromellitic acid.(4) Bromine component in the catalysts suppressed the deactivation of heavy metal caused by the oxidation product.(5) Pyromellitic acid was produced from durene with the maximum yield of about 90mol%.

The hydrolysis reaction of 4, 5-bischloromethyl-m-xylene in alkali solution has been studied. The reaction was accelerated by emulsifing the raw material in alkali solution with surface active agent. The yield of 4, 6-bismethylol-m-xylene was about 90mol%, higher about 20mol%, than that obtained without surface active agent. It was found that the reaction-accelerating effect varied with the kind of surface active agent used, the agents of anionic series being more effective than those of nonionic series.Other factors responsible for the reaction were also examined in connection with reaction temperature, concentration of raw materials and alkali, etc.The hydrolysis of chloromethylpseudocumene was made by the same method with the result that its reaction mechanism was somewhat different from that of 4, 6-bischloromethyl-m-xylene.

Advantages of depressed cladding single-mode fibers have been recognized for a couple of years, and many studies of these fibers by the MCVD method have been published. However, only a few studies have been reported on the VAD method.1,2 We now report a new simple technique for fabrication of depressed cladding single-mode fibers by the VAD method with low losses such as 0.40 dB/km at 1.30 μm and 0.28 dB/km at 1.55 μm.

An ultra wide bandwidth optical fibre has been fabricated by a v.a.d. method. The 6 dB bandwidth of the fibre is 6.53 GHzkm at 1.31 ?m.