Strong Light Source Research Articles

Emission property of Sn2 +-doped ZnO–P2O5 glass

Photoluminescent properties of amorphous zinc phosphate glass, containing Sn2+ as an emission center, were investigated. Varying the chemical composition changed both the excitation and emission properties. The redox reaction that occurred during melting was found to affect both valences of transition metal and Sn cations to change the emission property of the Sn2+-containing glass. We have also examined the emission property of substituted SnO–ZnO–P2O5 glass, and demonstrated that the emission color can be tailored by chemical composition to obtain blue, white, and red. It is notable that the quantum efficiency value of the present RE-free glass is comparable to that of crystal phosphor such as MgWO4. We have, therefore, emphasized that transparent inorganic glass phosphor will be one of the fascinating emitting materials adoptable to future strong LED light source.

Optical design of a reflective concentrator mirror utilizing higher order cylindrical surfaces

In this paper, we present a new and highly efficient solar concentrating mirror. It is composed of partial high-order cylinder inner wall which is determined by two sets of specific coefficients a2, a4, a6, a8, a10, a12, a14, a16 and C. According to the higher-order cylindrical equation and the optical law of reflection, the relationship between the direction vectors of sunbeams reflected from the cylindrical inner wall and the coefficients of a higher order polynomial equation, a2,a4, a6, a8, a10, a12, a14, a16 and C is derived. By optimizing these coefficients, all sunbeams incident on the inner wall of higher-order cylinder can be reflected and focused into a very thin line segment parallel to the cylindrical busbar, which means line focus. Two sets of particular coefficients associated with the high- order cylindrical surface are obtained by using particle swarm optimization algorithm. The focusing effect of the solar concentrating mirror, defined by the particular set of coefficients, is demonstrated by using computer simulations. The concentrator mirror has a light compression ratio of about 148 : 1 and its linear spot can be used as a strong light source or a high temperature heat source. The higher-order cylindrical mirror can be made of metal or glass in three steps: cutting, grinding, and polishing, and may also be formed by a higher order cylindrical framework and an aluminized polyester film laid on the framework.

Ultracompact Refractive Index Sensor Based on Surface-Plasmon-Polariton Interference

Using an ultracompact groove-slit-groove (GSG) structure, a refractive index sensor with a broadband response is proposed and experimentally demonstrated. Due to the interference of surface plasmon polaritons (SPPs), the transmission spectra in the GSG structure exhibit oscillation behaviors in a broad bandwidth, and they are quite sensitive to the refractive index of the surroundings. Based on the principle, the characteristics of its refractive index sensing are demonstrated experimentally. In the experiment, the structure is illuminated with a bulk light source (not a tightly focused light source) from the back side. This decreases the difficulty of the experimental measurement and can protect strong light sources from damaging the detection samples. Meanwhile, the whole structure of the sensor can be made more ultracompact without considering the influence of the incident waves.

Spectral, electron microscopic and chemical investigations of gamma-induced purple color zonings in amethyst crystals from the Dursunbey-Balıkesir region of Turkey

Amethyst crystals on matrix specimens from the Dursunbey-Balıkesir region in Turkey have five representative purple color zonings: dark purple, light purple, lilac, orchid, and violet. The purple color zonings have been analyzed with optical absorption spectra in the visible wavelength region, chemical full trace element analyses (inductively coupled plasma-atomic emission spectroscopy and inductively coupled plasma-mass spectroscopy), and scanning electron microscopic images with high magnification. It can be proposed that the production of the purple color in amethyst crystals is due to three dominant absorption bands centered at 375, 530, and 675 nm, respectively. In addition, the purple color zonings are also due to four minor absorption bands centered at 435, 480, 620, and 760 nm. X-ray diffraction graphics of the investigated amethyst crystals indicate that these crystals are composed of a nearly pure alpha-quartz phase and do not include any moganite silica phase and/or other mineral implications. Trace element analyses of the amethyst crystals show five representative purple color zonings, suggesting that the absorption bands can be mainly attributed to extrinsic defects (chemical impurities). However, another important factor that influences all structural defects in amethyst is likely to be the gamma irradiation that exists during amethyst crystallization and its inclusion in host materials. This gamma irradiation originates from the large underlying intrusive granitoid body in the region of amethyst formation. Irradiation modifies the valence values of the impurity elements in the amethyst crystals. It is observed that the violet-colored amethyst crystals have the most stable and the least reversible coloration when exposed to strong light sources. This situation can be related to the higher impurity content of Fe (2.50 ppm), Co (3.1 ppm), Ni (38 ppm), Cu (17.9 ppm), Zn (10 ppm), Zr (3.9 ppm), and Mo (21.8 ppm).

Reproducibility of straylight measurement by C-Quant for assessment of retinal straylight using the compensation comparison method

Straylight gives the appearance of a veil of light thrown over a person's retinal image when there is a strong light source present. We examined the reproducibility of the measurements by C-Quant, and assessed its correlation to characteristics of the eye and subjects' age. Five repeated straylight measurements were taken using the dominant eye of 45 healthy subjects (age 21-59) with a BCVA of 20/20: 14 emmetropic, 16 myopic, eight hyperopic and seven with astigmatism. We assessed the extent of reproducibility of straylight measures using the intraclass correlation coefficient. The mean straylight value of all measurements was 1.01 (SD 0.23, median 0.97, interquartile range 0.85-1.1). Per 10years of age, straylight increased in average by 0.10 (95%CI 0.04 to 0.16, p < 0.01]. We found no independent association of refraction (range -5.25 dpt to +2 dpt) on straylight values (0.001; 95%CI -0.022 to 0.024, p = 0.92). Compared to emmetropic subjects, myopia reduced straylight (-.011; -0.024 to 0.02, p = 0.11), whereas higher straylight values (0.09; -0.01 to 0.20, p = 0.09) were observed in subjects with blue irises as compared to dark-colored irises when correcting for age. The intraclass correlation coefficient (ICC) of repeated measurements was 0.83 (95%CI 0.76 to 0.90). Our study showed that straylight measurements with the C-Quant had a high reproducibility, i.e. a lack of large intra-observer variability, making it appropriate to be applied in long-term follow-up studies assessing the long-term effect of surgical procedures on the quality of vision.

Photophoretic velocimetry—a new way for the in situ determination of particle size distribution and refractive index of hydrocolloids

The migration of particles induced by the forces of light is known as photophoresis. The photophoretic velocity of particles under the influence of a strong light source, e.g. a laser beam, is recorded and measured by means of digital image processing which is called photophoretic velocimetry (PPV). The photophoretic velocity depends on the particle size as well as on its refractive index. By applying PPV, we show the determination of the intrinsic properties of polystyrene (PS), melamine resin (MF) and SiO(2) particles, deduced from velocity distributions of both monodisperse as well as polydisperse suspensions. Especially the continuous determination of the refractive index of single hydrocolloids is of great interest for quality assurance and the discrimination of polydisperse biological or inorganic samples. Also, PPV is not restricted to in water dispersed samples only.

Fiber Bragg Gratings Array for Structural Health Monitoring

Experimental and numerical analyses have been carried out to demonstrate the feasibility and evaluate the limitation of using fiber Bragg gratings for impact source location on a cold-rolled aluminum plate. Within the area enveloped by a four-FBG-array, source location is reasonably accurate. Beyond that area, prediction error may not be acceptable. Numerical simulations show that such error may be attributed to the limitation of equipment resolution on the one hand, and angular insensitivity of the FBG on the other hand. Based on the results, it is reasoned that prediction accuracy can be improved by employing stronger light source, steeper filter response, and orthogonal rosettes instead of single axis FBGs.

Phase Destruction upon Photopolymerization of Cholesteric Liquid Crystal Blue Phases with Mono- and Diacrylate Constituents

Abstract We report an anomalous destruction of cholesteric blue phases I and II upon photopolymerizing a liquid crystal mixture composed of mono- and diacrylate monomers. The platelet texture characteristic of the blue phase collapsed when the sample was irradiated by a weak UV light source, while usual freezing of both blue phases I and II was obtained upon photopolymerization by a stronger light source. The phase destruction seems to be reflecting the robustness of the cubic lattice structure against external purterbations.

Microstructures of coarse-grained marbles, analyzed using a new technique based on the bireflectance of calcite

A new approach to quantify microstructures of coarse-grained marbles is presented. This technique is based on the intensity of light reflectance in dependence of the crystallographic orientation of calcite grains. The technique setup consists of a high-resolution camera, a strong light source and the polished sample in reflection position. Microstructural data obtained with this method are comparable with those obtained by light microscopy or by secondary electron microscopy. However, the new approach reflects the grain size distribution even more accurately than in the case of other techniques, because it allows an easy quantification of larger sample surfaces. Therefore, in contrast to established techniques, microstructural analysis and statistics can also be performed for coarse-grained samples with grains that exceed diameters of 1 cm. With this new technique, coarse-grained mylonitic microstructures from Naxos were quantified, which in turn allowed relating different microfabrics to different strain localization episodes within a large-scale shear zone complex.

Laryngospasm

Laryngospasm

イメージセンシング技術とその応用 時分割投射光による実時間高速高精度３次元モデル取得のための複数視点システム

We introduce a multiple-viewpoint 3-D measurement system that is suitable for acquiring high-speed and high-accuracy 3-D model model movie in real-time. The present system consists of multiple range finders, and each one consists of a camera and projector. We use a high-speed 3-D image sensor as a camera and used the range finders to measure various target objects from multiple viewpoints in a time-division manner. We then carried out a general linear calibration and evaluated the range accuracy. We demonstrated acquisition speeds of up to 10.6 range-maps/s for two cameras and 6.1 range-maps/s for three cameras in real-time. Our system is suitable for high-accuracy 3-D model acquisition with, at 1200 mm, an error to distance of less than 0.2 %. We show the applicability of the present system for when a strong light source is used. The present system is suitable for complete 3-D model acquisition since the detected areas of the overlap in multiple-viewpoint 3-D range finding is small.

Assessment and Application of the Biotin Switch Technique for Examining Protein S-Nitrosylation under Conditions of Pharmacologically Induced Oxidative Stress

Protein S-nitrosylation has emerged as a principal mechanism by which nitric oxide exerts biological effects. Among methods for studying protein S-nitrosylation, the biotin switch technique (BST) has rapidly gained popularity because of the ease with which it can detect individual S-nitrosylated (SNO) proteins in biological samples. The identification of SNO sites by the BST relies on the ability of ascorbate to generate a thiol from an S-nitrosothiol, but not from alternatively S-oxidized thiols (e.g. disulfides, sulfenic acids). However, the specificity of this reaction has recently been challenged, prompting several claims that the BST may produce false-positive results and raising concerns about the application of the BST under oxidizing conditions. Here we perform a comparative analysis of the BST using differentially S-oxidized and S-nitrosylated forms of protein tyrosine phosphatase 1B, as well as intact and lysed human embryonic kidney 293 cells treated with S-oxidizing and S-nitrosylating agents, and verify that the assay is highly specific for SNO. Strikingly, exposure of samples to indirect sunlight from a laboratory window resulted in artifactual ascorbate-dependent signals that are likely promoted by the semidehydroascorbate radical; protection from sunlight eliminated the artifact. In contrast, exposure of SNO proteins to a strong ultraviolet light source (SNO photolysis) prior to the BST provided independent verification of assay specificity. By combining BST with photolysis, we have shown that anti-cancer drug-induced oxidative stress facilitates the S-nitrosylation of the major apoptotic effector glyceraldehyde-3-phosphate dehydrogenase. Collectively, these experiments demonstrate that SNO-dependent signaling pathways can be modulated by oxidative conditions and suggest a potential role for S-nitrosylation in antineoplastic drug action.

IDENTIFICATION OF REPRODUCTIVE STATUS IN FEMALE FROGS—A QUANTITATIVE COMPARISON OF NINE METHODS

Many techniques commonly used by herpetologists for monitoring amphibian populations and communities yield censuses of the total adult population size (N). However, for many studies, e.g., of reproductive output, development of populations and potential for evolutionary changes, the effective population size (Ne) must be known. While modern molecular techniques make it possible to measure Ne, they are expensive, work-intensive and may not be possible or necessary for many questions on amphibian reproduction. For females of two species of water frog (Rana lessonae and R. esculenta), we investigate the effectiveness of several techniques to determine the presence or absence of eggs. The direct methods are (1) dissection of dead frogs and (2) a small skin incision into the abdominal side of live females. The indirect methods, all applied to live frogs, include (3) visual inspection of body shape, (4) tactile inspection of the epidermis, (5) transillumination with a strong cold light source, (6) ultrasound, (7) electromagnetic measurement of total body electrical conductivity (TOBEC), (8) calculation of body condition index and (9) analysis of blood plasma testosterone titers. Only two indirect methods were somewhat successful at predicting whether females were gravid. Testosterone titers (9) yielded the best results (ca. 80–90% effective). Body condition (8) was also significantly related to egg presence or absence, but predicted gravidity only weakly. We suggest that a combination of skin incision and hormone analysis provides a fairly good estimate of gravidity. When complemented by mark-recapture techniques and performed on the same individuals at different times of the season, this combination yields estimates not only of the reproductive output of the study population but also of the relative contribution of different females.

Feature Article: Laser-Based Ionization Techniques in Rare Isotope Research: Production, Spectroscopy, and Detection

The interaction of the atomic nucleus and its electromagnetic properties, represented by spin, nuclear moments, and charge radii, with the electronic shell reveals a detailed view into existence, behavior, structure, and stability of nuclear matter in its ground state. Studies along the valley of β-stability of the nuclear chart and particularly far out into the range of unstable short-lived radioactive nuclides are of major interest, for example, for the development of corresponding models. In parallel, optical techniques developed in this context have found widespread applications also for analytics of rare isotopes. Almost immediately after the development of tunable lasers as strong and quasi-monochromatic light source around the year 1960, laser spectroscopic techniques have emerged and found broad acceptance in this field, where they revolutionized and almost completely replaced the former methods of classical optical spectroscopy.

Experimental visualization of solute transport and mass transfer processes in two-dimensional conductivity fields with connected regions of high conductivity.

Solute transport displaying mass transfer behavior (i.e., tailing) occurs in many aquifers and soils. Spatial patterns of hydraulic conductivity may play a role because of both advection and diffusion through isolated low conductivity areas. We demonstrated such processes in laboratory experiments designed to visualize solute transport through a thin chamber (40 cm x 20 cm x 0.64 cm thick) packed with glass beads and containing circular emplacements of smaller glass beads with lower conductivity. The experiments used three different contrasts of conductivity between the large-bead matrix and the emplacements, targeting three different regimes of solute transport: low contrast, targeting macrodispersion; intermediate contrast, targeting advection-dominated mass transfer between the high-conductivity regions and the emplacements; and high contrast, targeting diffusion-dominated mass transfer. Use of a strong light source, a high-resolution CCD camera, and a colorimetric dye produced images with a spatial resolution of about 400 microm and a concentration range of approximately 2 orders of magnitude. These images confirm the existence of the three different regimes, and we observed tailing driven by both advection and diffusion. Outflow concentration measured by spectrophotometer achieved 3 orders of magnitude in concentration range and showed good agreement with known models in the case of dispersion and diffusive mass transfer, with estimated parameters close to a priori predictions. Existing models for diffusive mass transfer did notfitthe breakthrough curves from the intermediate-contrast chamber, but a model of slow advection through cylinders did. Thus, both breakthrough curves and chamber images confirm that different contrasts in small-scale K lead to different regimes of solute transport and thus require different models of upscaled solute transport.

Development of the White Light-Emitting Diode-Illuminated Digestive Endoscope

Aim: Videoendoscope system for digestive tract has been well developed and widely distributed throughout the world. In a conventional videoendoscope system, large light source equipment and light-guide fiber bundle are essential, which impose some limitations on the reduction of the size of the system and the design of the scope. Capsule endoscope is useful mainly for small intestine, but it is not suitable for routine esophago-gastro-duodenoscopy and colonoscopy. Recently, light-emitting diode (LED) has been rapidly developed as a new strong light source. So, we have started to develop the new LED-illuminated digestive endoscope system. Methods: We have applied newly developed white LED as the light source of prototype LED-illuminated digestive endoscope. The new ultra-violet LED-based one-tip type white LED has been developed using unique epitaxial growth techniques and advanced optical characterization techniques (developed by Professor Tsunemasa Taguchi, Department of Electricity and Electronics, Yamaguchi University Faculty of Engineering; and Mitsubishi Cable Industries, Ltd.). The new white LED has the highest external quantum efficiency (43%). It also has better color rendering properties at the red region than conventional white LED. The new white LED was located at the distal end of the prototype scope, which was based on the conventional videoendoscope system (Fuji Photo Optical, Co., Ltd.). We observed the esophagus and stomach of a beagle dog under painless state of general anesthesia by well-trained veterinarian (Yamamoto Animal Hospital). This study was conducted under the approval of institutional review board. Support for the study was received from Ministry of Education, Culture, Sports, Science and Technology, Japan. Results: Esophageal mucosa and gastric mucosa of beagle dog was clearly observed under illumination of new white LED. The intensity of luminous flux of new white LED was smaller than light-source of conventional system, but enough for observation. Color rendering properties at red region for actual esophagus and stomach were good, and reddish area and submucosal blood vessels were well recognized. Conclusions: Our results suggested that the new white LED is suitable for the light source of digestive endoscope from the point of color rendering properties and quantity of luminous flux. We will continue further development of this advanced prototype LED-illuminated digestive endoscope.

Growth Physiology of Spring Wheat Under Saline Conditions

Growth Physiology of Spring Wheat Under Saline Conditions

The effects of polishing and bleaching on the colour of discoloured teeth in vivo

Bleaching is an effective method for restoring the colour of discoloured vital teeth. Power bleaching, in particular, in which a bleaching solution containing 35% hydrogen peroxide is activated by a strong light source using a plasma arc, makes it possible to bleach teeth effectively in a short time. The purpose of this study was to determine how polishing or power bleaching the tooth surface affects tooth colour. The subjects selected were patients who had slightly discoloured teeth. The colour of precisely identified sites on six anterior teeth was measured before treatment, after polishing and after bleaching, to ascertain changes in colour. The measurements revealed that tooth colour changes slightly after polishing, but it shows a much greater change after bleaching, and that the post‐bleaching change in tooth colour was caused both by elevation of lightness and reduction of yellowness. They also revealed that the colour difference between pre‐treatment and post‐bleaching does not depend on the type of tooth. These results suggested that power bleaching is an effective technique for improving slightly discoloured vital teeth, regardless of the type of tooth.

The effects of polishing and bleaching on the colour of discoloured teeth in vivo.

Bleaching is an effective method for restoring the colour of discoloured vital teeth. Power bleaching, in particular, in which a bleaching solution containing 35% hydrogen peroxide is activated by a strong light source using a plasma arc, makes it possible to bleach teeth effectively in a short time. The purpose of this study was to determine how polishing or power bleaching the tooth surface affects tooth colour. The subjects selected were patients who had slightly discoloured teeth. The colour of precisely identified sites on six anterior teeth was measured before treatment, after polishing and after bleaching, to ascertain changes in colour. The measurements revealed that tooth colour changes slightly after polishing, but it shows a much greater change after bleaching, and that the post-bleaching change in tooth colour was caused both by elevation of lightness and reduction of yellowness. They also revealed that the colour difference between pre-treatment and post-bleaching does not depend on the type of tooth. These results suggested that power bleaching is an effective technique for improving slightly discoloured vital teeth, regardless of the type of tooth.

Near-field recording with high optical throughput aperture array

To create and utilize a strong light source with sub-wavelength size has opened up a new frontier in optics, the near-field optics. One of the most attractive applications of the near-field optics is near-field optical data storage. The optical memory with high density and high data transfer rate is highly demanded to utilize an array of high throughput nano-scaled light sources for writing and reading bits on a medium. In this paper, we propose a hybrid structure of vertical cavity surface emitting laser (VCSEL) and aperture array for optical near-field memory head, namely VCSEL/NSOM. A technological solution for fabrication of the aperture array with Si micromachining technology is presented. An investigation of the optical performance of the near-field light at the apertures of the Si micromachined aperture array is presented. The primary result of writing and reading bits on a phase change (PC) medium using the fabricated structure is demonstrated.