Intensity Of Light Source Research Articles

Uneven intensity change correction of speckle images using morphological Top-Hat transform in digital image correlation

By comparing two digital speckle images recorded before and after deformation, two-dimensional digital image correlation (DIC) method can accurately determine the in-plane displacement fields and strain fields. In a practical measurement, however, the variance of light source intensity, location and direction will cause the random uneven intensity change of the random speckle images and will lead to the obvious measurement error. Numerical simulation experiment is first carried out to analyse the influence of the recorded speckle images undergoing uneven light variation on DIC measurement accuracy. Then, a correction method for speckle images with uneven intensity change is proposed based on morphological Top-Hat transform. In addition, quantitative measurements of both in-plane rotation of a rigid body and three-point bending beam are investigated experimentally by DIC to verify the feasibility of the correction method. Experimental results show that the measurement accuracy of DIC is improved dramatically after the procedure of uneven light variation correction.

Proposal of coherent Cherenkov radiation matched to circular plane wave for intense terahertz light source

We propose a high-peak-power terahertz-wave source based on an electron accelerator. By passing an electron beam through a hollow conical dielectric with apex facing the incident electron beam, the wave front of coherent Cherenkov radiation generated on the inner surface of the hollow conical dielectric matches the basal plane. Using the electron beam generated at the Laboratory for Electron Beam Research and Application at Nihon University, the calculated power of coherent Cherenkov radiation that matched the circular plane (CCR-MCP) was above 1 MW per micropulse with a short interval of 350 ps, for wavelengths ranging from 0.5 to 5 mm. The electron beam is not lost for generating the CCR-MCP beam by using the hollow conical dielectric. It is possible to combine the CCR-MCP beams with other light sources based on an accelerator.

Excitonic Crystal, Nanotechnology and New Prospect for Optoelectronics

The review demonstrates the results of development of growth technology for perfect and free of contamination gallium phosphide (GaP) crystals and investigation of influence of crystallization conditions on quality and properties of the crystals. The long-term ordered and therefore close to ideal crystals repeat behavior of the best nanoparticles with pro- nounced quantum confinement effect. These perfect crystals are useful for application in top-quality optoelectronic devic- es as well as they are a new object for development of fundamentals of solid state physics. Since the time of original preparation by the author in the 1960s of gallium phosphide crystals doped by nitrogen (GaP:N), followed by the introduction of the excitonic crystal concept in the 1970s, the best methods of bulk, film and na- noparticle crystal growth were elaborated. The results of semi centennial evolution of GaP:N properties are compiled in the paper. Novel and useful properties of perfect GaP including its stimulated emission, very bright and broadband lumi- nescence at room temperature were observed. These results provide a new approach to selection and preparation of perfect materials for optoelectronics and a unique opportunity to realize a new form of solid-state host - the excitonic crystal as high intensity light source with expected low threshold for generation of non-linear optical effects. Using the example of GaP, here is proposed the cheap, resource-saving and impactful way for development of optoelec- tronics with the help of a special transformation of an ordinary semiconductor into the base material for various device structures.

Characterization of ion-induced radiation effects in nuclear materials using synchrotron x-ray techniques

Abstract

Folic acid-conjugated chromium(III) doped nanoparticles consisting of mixed oxides of zinc, gallium and tin, and possessing near-infrared and long persistent phosphorescence for targeted imaging of cancer cells

Folic acid-conjugated luminescent nanomaterials have long been widely used in targeted bioimaging, often simultaneously acting as vehicles for drug delivery. They often require, however, intense light sources for photoexcitation, and this often results in photobleaching, strong luminescence background, and strong light scattering. This article describes the preparation of nanoparticles (NPs) of the type Zn1.1Ga1.8Sn0.1O4 doped with Cr(III) ions and surface-modified with folic acid. The functionalization of the NPs was monitored via measurement of zeta potentials, FTIR spectra and thermogravimetry. Cell viability and biocompatibility were tested using the MTT kit. The NPs have a size of 220 nm and were characterized by dynamic X-ray diffraction, light scattering, field emission scanning electron microscopy and high-resolution transmission electron microscopy. After annealing the NPs for 10 min at 300 °C and irradiating them with 254 nm light for 10 min, they display deep red emission that persists for up to 10 h. The NPs are easily dispersed, small-sized, and crystalline. In our perception, the new material with its long decay time offers quite novel features in terms of targeted optical imaging in providing high resolution, weak disturbance by background luminescence, and the absence of light scattering. They were successfully applied to image MCF-7 and A549 cells.

Guidelines of care for vascular lasers and intense pulse light sources from the European Society for Laser Dermatology.

Lasers and non-coherent intense pulse light sources (IPLS) are based on the principle of selective photothermolysis and can be used for the treatment of many vascular skin lesions. A variety of lasers has been developed for the treatment of congenital and acquired vascular lesions which incorporate these concepts into their design. Although laser and light sources are very popular due to their non-invasive nature, caution should be considered by practitioners and patients to avoid permanent side-effects. The aim of these guidelines is to give evidence-based recommendations for the use of lasers and IPLS in the treatment of vascular lesions. These guidelines were produced by a Consensus Panel made up of experts in the field of vascular laser surgery under the auspices of the European Society of Laser Dermatology. Recommendations on the use of vascular lasers and IPLS were made based on the quality of evidence for efficacy, safety, tolerability, cosmetic outcome, patient satisfaction/preference and, where appropriate, on the experts' opinion. The recommendations of these guidelines are graded according to the American College of Chest Physicians Task Force recommendations on Grading Strength of Recommendations and Quality of Evidence in Clinical Guidelines. Lasers and IPLS are very useful and sometimes the only available method to treat various vascular lesions. It is of a paramount importance that the type of laser or IPLS and their specific parameters are adapted to the indication but also that the treating physician is familiar with the device to be used. The crucial issue in treating vascular lesions is to recognize the immediate end-point after laser treatment. This is the single most important factor to ensure both the efficacy of the treatment and avoidance of serious side-effects.

Analyte-induced photoreduction method for visual and colorimetric detection of tyrosine

A new method based on photochemical formation of silver nanoparticles (AgNPs) was developed for detection of tyrosine (Tyr). To selectively detect Tyr and to simplify the detection procedure, the photoactivity of Tyr was utilized to trigger the photochemical reduction in production of AgNPs. The drastic change of solution color caused by the surface plasmon resonance (SPR) absorption band of the formed AgNPs was used to extract the quantitative information of Tyr. This developed method is simple in detection, while both the sensitivity and selectivity are significant improved. Meanwhile, the solution color was changed from colorless to dark yellow after the formation of AgNPs, which allows a much higher sensitivity in visual identification when compared with the SPR band shifting technique commonly, used in conventional colorimetric methods. To optimize the detection system and to understand the mechanism in this proposed method, parameters such as irradiation time, intensity of light source, and the concentration of Tyr were systematically examined. Results indicated that these factors mainly affected the reaction rate of photoreduction. The morphologies of the formed AgNPs were similar, but with small differences in particle sizes. In the examination of selectivity, sixteen other amino acids were examined. Results indicated that only amino acids of tryptophan, cysteine and histidine are photoactive and possess potential interferences in analysis of Tyr. Quantitative studies indicated that a linear response up to 10μM with a detection limit of 100nM could be obtained. For visually detection, color change could be observed with a concentration as low as 500nM of Tyr.

Coextruded, aligned, and gradient-modified poly(ε-caprolactone) fibers as platforms for neural growth.

Polymeric fibers are of increasing interest to regenerative medicine, as materials made from these fibers are porous, allowing for cell infiltration, influx of nutrients, and efflux of waste products. Recently, multilayered coextrusion has emerged as a scalable and rapid fabrication method to yield microscale to submicron fibers. In this report, we describe the multilayered coextrusion of aligned poly(ε-caprolactone) (PCL) fibers, followed by a simple photochemical patterning to create surface-immobilized gradients onto the polymer fibers. PCL fibers were photochemically decorated with a linear gradient of propargyl benzophenone using a gradient photomask to control light source intensity. The pendant alkynes were then able to undergo the copper-catalyzed azide-alkyne cycloaddition reaction with an azide-modified IKVAV peptide to further functionalize the surface. Gradient-modified IKVAV fibers were evaluated for neural cell adhesion and neural differentiation, using PC-12 cells cultured onto the fibers. The aligned gradient fibers provided directional cues for neurite outgrowth and alignment of neural cells, as observed by cellular elongation, neurite differentiation, and orientation. The work presented herein describes a scalable fiber system combined with simple chemical patterning to generate aligned fibers with controlled surface gradients as cell-seeding scaffolds.

An intuitive user interaction method using multi-sensors for pencil drawing filter of NPR rendering in mobile devices

The user interface is one of the most important factors to use various functions of mobile device easily. Recently, the importance of the user interface has been increased after Apple emphasized emotional UX(User eXperience) by applying multi-touches to iPhone. Mobile device Manufacturers have tried to apply embedded sensors to apps as user interface. Microphone was applied to execute functions combined with voice recognition and GPS sensor was used to find a location in navigation apps or game apps. Like these services, several sensors have roles of interface between user and device. In this paper, we propose an intuitive user interaction method using multi-sensors in NPR(Non-Photorealistic) rendering. The proposed method renders pencil drawing filter for a given photo image with the direction and strength of line strokes which are applied in vector fields. At this point, the method changes direction of stroke with x-coordinate values and y-coordinate values and control the strength of the stroke with z-coordinate values after catching three coordinate values in real-time from the orientation sensor on a mobile device. The method also adjusts brightness of image by transforming intensity of light from the light sensor. The light sensor updates intensity of light source continuously. If the user brings the mobile device closer to the external light source, the light sensor value will increase and the intensity of brightness becomes stronger. In addition, the user can make an attenuation effect with orientation sensor combined with light sensor for specific scope in a photo image and change the attenuation scope by moving action of his holding mobile device. This is a user interaction method for emotional image processing using sensors in mobile devices. We developed an app which generated pencil drawing filter effect for a photo image. We experimented sensor based emotional user interaction and compared various results of image processing effects using two combinatorial sensors. Finally, this paper proved efficiency through the experimental results and evaluated the effectiveness of the proposed method.

A Pilot Study Examining Density of Suppression Measurement in Strabismus

Purpose: Establish whether the Sbisa bar, Bagolini filter (BF) bar, and neutral density filter (NDF) bar, used to measure density of suppression, are equivalent and possess test-retest reliability. Determine whether density of suppression is altered when measurement equipment/testing conditions are changed.Methods: Our pilot study had 10 subjects aged ≥18 years with childhood-onset strabismus, no ocular pathologies, and no binocular vision when manifest. Density of suppression upon repeated testing, with clinic lights on/off, and using a full/reduced intensity light source, was investigated. Results were analysed for test-retest reliability, equivalence, and changes with alteration of testing conditions.Results: Test-retest reliability issues were present for the BF bar (median 6 filter change from first to final test, p = 0.021) and NDF bar (median 5 filter change from first to final test, p = 0.002). Density of suppression was unaffected by environmental illumination or fixation light intensity variations. Density of suppression measurements were higher when measured with the NDF bar (e.g. NDF bar = 1.5, medium suppression, vs BF bar = 6.5, light suppression).Conclusions: Test-retest reliability issues may be present for the two filter bars currently still under manufacture. Changes in testing conditions do not significantly affect test results, provided the same filter bar is used consistently for testing. Further studies in children with strabismus having active amblyopia treatment would be of benefit. Despite extensive use of these tests in the UK, this is to our knowledge the first study evaluating filter bar equivalence/reliability.

Paramecium: a promising non-animal bioassay to study the effect of 808 nm infrared diode laser photobiomodulation.

Photobiostimulation and photobiomodulation (PBM) are terms applied to the manipulation of cellular behavior using low intensity light sources, which works on the principle of inducing a biological response through energy transfer. The aim of this investigation was to identify a laboratory assay to test the effect of an infrared diode laser light (808 nm) on cell fission rate. Sixty cells of Paramecium primaurelia were divided in two groups of 30. The first group (test group) was irradiated, at a temperature of 24°C, for 50 sec by a 808 nm diode laser with a flat top handpiece [1 cm of spot diameter, 1 W in continuous wave (CW), 50 sec irradiation time, 64 J/cm(2) of fluence]. The second group (control group) received no laser irradiation. All cells were transferred onto a depression slide, fed, and incubated in a moist chamber at a temperature of 24°C. The cells were exposed and monitored for 10 consecutive fission rates. Changes in temperature and pH were also evaluated. The exposed cells had a fission rate rhythm faster than the control cells, showing a binary fission significantly (p<0.05) shorter than unexposed cells. No significant effects of laser irradiation on pH and temperature of Paramecium's lettuce infusion medium were observed. The 808 nm infrared diode laser light, at the irradiation parameters used in our work, results in a precocious fission rate in P. primaurelia cells, probably through an increase in metabolic activity, secondary to an energy transfer.

Detection of Semen Stains in Rape Cases by a Very High Powered UV-VIS Light Source, Facilitated Conviction of Accused Person

Detection of semen in forensic cases mostly sexual assault or abuse is critical for evidence collection. A portable forensic light source, which emits wavelength from 430 nm to 700 nm (UV to VIS) and filters were used. The very high intensity light source detected semen in darkness and daylight using wavelength between 415 nm to 490 nm. ABO blood grouping method is an oldest method used in forensic biology for grouping purpose. But now a days, DNA fingerprinting is an advanced technique used to solve crimes like gang rape. Even though in this case, simplest and oldest ABO blood grouping method helped to solve gang rape case. In present case, victim was 5 years old girl who was raped by a person. Screening the semen stains using portable forensic light source and primary testing of semen stains from different places on victim’s undergarments was done. ABO blood grouping of each selected semen stains were done by absorption-elution method. Those selected stains showed blood group which matched with the accused person’s blood group. Thus the accused person was convicted in this heinous crime.

The Recent Rapid Development of the Directed-Energy, Home-Use Device Sector

This article presents an overview of this exciting new technology category, the development of the industry, and future trends in at-home cutaneous therapy using ‘directed energy’. New equipment directed at unwanted hair removal, traditional skin blemishes, and new targets are being developed using novel Class 1C lasers and intense light sources. Other directed energy devices include electromagnetic energy sources beyond those in the visible light and infrared spectrum, such as microwaves, radio frequency, and high frequency focused ultrasound. Both cosmetic and medical applications are being exploited to provide efficacy and specificity of treatment at the consumer-use level. Future applications will combine different directed energy sources to optimise results. Early clinical data following the use of home-use devices (HUDs) is indicative of at least temporary hair reduction and skin improvements, and several safety studies have shown most devices to be safe for consumer use. The HUD category is a new and fast emerging market, worth multimillions of dollars annually, and the emergence of consumer use devices reflects the needs of an ageing, wealthy, and wellness-oriented population. The new miniaturised products and appliances entering the market employing powerful and complex technology do, however, raise some health concerns. Safety standardisation and national regulation, however, seem to be somewhat behind the market development.

Quantitative colour schlieren development

This work evaluates the potential for producing quantitative data of the density field using a two-dimensional colour schlieren system within the test section of a shock tube. Density gradient components, magnitude and direction, form the basis of the quantitative evaluation. These are encoded onto an imaging plane by means of a colour-coded source mask placed along the optical axis of the schlieren system. Direction is indicated by the relative ratios of the three primary colours: red, green and blue (RGB). Magnitude is indicated by the relative intensities of the RGB values. Sensitivity of the system is adjusted by an iris diaphragm placed in the cutoff plane. The method described is applied to the focusing of a shock wave in a parabolic cavity. The experimental results of the schlieren technique are compared to computational simulations with synthetic two-dimensional colour and magnitude coding applied to the results. The source masks designed and used proved to require a greater intensity light source and thus the design of an LED light source was developed. The CFD solutions were converted into an image format directly comparable to the photographic images obtained. Image processing techniques have been employed to deconstruct photographs to allow for quantitative comparisons with a calibration lens. Density gradient direction has been conclusive; however, density gradient magnitude is not yet accurately determined due to light source constraints.

A numerical demonstration of far field photon intensity enhancement without stimulated emission

A laser is conventionally generated by pumping molecules to a population inversion condition followed by stimulated emission to produce coherent, monochromatic, high intensity beams of light. Herein, we numerically show an alternative way to achieve far field photon intensity enhancement without stimulated emission. The intensity enhancement is achieved by taking advantage of the physical cross section variation of the diffracted light in a two dimensional silver nanoparticle array and the excitation of the quadrupole mode of the metal nanoparticles. The results have potential applications in the development of high intensity light sources for nanodevices.

Quantitative study of reflection of sunlight by a glass curtain wall resulting in a visual masking effect.

Because of the complexity of the shapes of the structures of buildings, the glass curtain walls of such buildings have different geometries; some of these glass curtain walls have high reflectivity and can strongly focus incident solar light. Under ideal conditions, the solar radiation flux incident onto the glass curtain wall and the solar flux reflected from the glass curtain wall can be theoretically determined. When exposed to an intense light source, human eyes exhibit a visual masking effect when processing an image; the resulting noise level and signal-to-noise ratio in the image are studied. Using field measurements to measure the reflected sunlight of two types of glass curtain walls, the energy distributions of the light reflected from these two different glass curtain walls are determined. This paper focuses on analysis of the experimental results and the cause of the visual masking effect due to the reflection of sunlight from a glass curtain wall and on the method of quantitative calculation of the visual masking effect.

Novel nanostructured-TiO2 materials for the photocatalytic reduction of CO2 greenhouse gas to hydrocarbons and syngas

In the current work an attempt has been made to synthesize novel high surface area nano-TiO2 materials (titanium dioxide nanoparticles/TNPs and nanostructured or mesoporous titanium dioxide using KIT-6 silica template/Meso. TiO2) in order to establish the photocatalytic reduction of CO2 greenhouse gas in the presence of H2O vapor to produce hydrocarbons and syngas. The synthesized materials have been characterized through N2-adsorption/desorption, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and ultraviolet–visible (UV–Vis) spectroscopy analysis techniques. The TNPs consists of an average 11nm of TiO2 particles, shows a higher surface area of 151m2/g than the commercial Aeroxide P25 TiO2 (53m2/g), and also demonstrates an enhanced adsorption capacity. However, the Meso. TiO2 has shown a higher surface area (190m2/g) and mesoporosity (4nm pores) than the TNPs and Aeroxide P25 TiO2, as confirmed by the characterizations. In the reaction, the TNPs with the enhanced adsorption capability, due to the high surface area and smaller nano-sized particle morphology, showed a higher syngas (CO, H2) production than the commercial Aeroxide P25 TiO2. However, the novel Meso. TiO2 showed more hydrocarbons (CH4, CH3OH) and a higher syngas production together with better reaction kinetics and stability due to its better characteristics than the commercial Aeroxide P25 TiO2. The key parameters that affect the activity have been optimized to increase fuel production. The reaction mechanism indicates competitive adsorption of CO2 and H2O vapors on the catalyst surface. The key parameters including the UV light source and UV intensity, H2O/CO2 ratios and catalyst shapes influence the catalytic performance, and therefore, these parameters have been optimized to increase the fuel products. Partial saturation of the active adsorption sites and the oxygen produced are the possible causes of the deactivation, however, the catalysts can be regenerated quickly through a simple evaporation technique.

Current Trends of Visible Light Communication(&lt;Feature&gt;New Aspects for the Application of LED Light Sources-Merging with Information Technology and Photonics-)

LED lights and LED traffic signal are spreading rapidly, and the research and the development of a visible optical communication by modulating the light intensity of the LED light source are advancing at the same time in recent years. In this paper, the characteristics and the application of visible light communication, and activities of standardization are explained.

Large reverse saturable absorption under weak continuous incoherent light.

In materials showing reverse saturable absorption (RSA), the optical absorbance increases as the power of the light incident on them increases. To date, RSA has only been observed when very intense light sources, such as short-pulse lasers, are used. Here, we show that hydroxyl steroidal matrices embedding properly designed aromatic molecules as acceptors and transition-metal complexes as donors exhibit high RSA on exposure to weak incoherent light at room temperature and in air. Accumulation by photosensitization of long-lived room-temperature triplet excitons in acceptors with a large triplet-triplet absorption coefficient allows a nonlinear increase in absorbance also under low-power irradiation conditions. As a consequence, continuous exposure to weak light significantly decreases the transmittance of thin films fabricated with these compounds. These optical limiting properties may be used to protect eyes and light sensors from exposure to intense radiation generated by incoherent sources and for other light-absorption applications that have not been realized with conventional RSA materials.

Synchrotron FTIR microscopy of synthetic and natural CO2–H2O fluid inclusions

Fluid inclusions provide a record of the physical and chemical composition of fluids that flow through the Earth's crust. Here, we describe a novel use of synchrotron Fourier Transform Infrared (FTIR) microscopy to map three parameters in individual fluid inclusions: (1) very low concentrations of CO2, (2) variations of the state of CO2 and (3) variations in water structure. The intensity of the synchrotron light source allows compositional mapping of individual fluid inclusions, which provides high-resolution images of the distribution of different CO2 and H2O species within individual inclusions. High resolution spectra of the CO2, recorded here for the first time in fluid inclusions, show the rotational lines of CO2 gas. The results reveal predicted as well as unexpected distributions of CO2 gas in the inclusions.