Yellow Radiation Research Articles

Biological effect of dual-frequency laser pulse radiation during pre-sowing treatment of rice seeds at early stages of development under stressful environmental conditions

The biological effect of two-frequency laser pulsed radiation produced on copper vapor during pre-sowing treatment of rice seeds of Veles and Leader varieties at early stages of development in extreme stressful environmental conditions has been studied. The copper vapor laser used in the experiment had the following output characteristics: wavelengths of 510.6 nm (green radiation line) and 578.2 nm (yellow radiation line), pulse duration of 15 ns, repetition frequency of 10 kHz, total pulse power of 10 kW, energy-power ratio between the green and yellow radiation lines 3/1 The interaction of laser radiation with wavelengths of 510.6 and 578.2 nm in the nonlinear medium of the seed caused the formation of additional wavelengths: a total wavelength of 271 nm (ultraviolet radiation) and a difference wavelength of 4.37 microns. Exposure to each of the four wavelengths in its spectral range could lead to the initiation of at least four radiation-induced biochemical reactions. It is shown that pre-sowing treatment of rice seeds with two-frequency laser pulsed radiation for 5–20 seconds had a stimulating effect on the growth and development of rice (the greatest effect was when exposed to 5–10 seconds), and also increased its stability when grown in extreme stressful environmental conditions (moisture deficiency, depleted soil) at early stages of development.

The influence of size on the photoluminescence properties of ZnO nanostructures

This paper describes methods for synthesizing different nanostructures of ZnO in aqueous solutions at low temperatures and examines the effect of the size of the synthesized samples on the photoluminescence (PL) spectra. As the diameters of the nanostructures increased, a decrease in the ratio of the intensity of the ultraviolet radiation band to the intensity of the yellow radiation band in the PL spectrum observed. It is found that changing the diameters of nanostructures from 15 nm to 1000 nm leads to a decrease in their bandgap energy (Eg) from 3.28 to 3.21 eV. When the diameters of the nanostructures were less than ~400 nm, it was found that the energy of the band gap was strongly depend on the size of the nanostructure, and that the bond was weaker as the size of the nanostructures exceeded 400 nm.

Virtual Reality-Based Education for Patients Undergoing Radiation Therapy

We built a virtual reality (VR) application that runs on a commercially available standalone VR headset that allows patients to view a virtual simulation of themselves receiving radiotherapy. The purpose of this study was to determine if this experience can improve patient understanding of radiotherapy and/or reduce patient anxiety. We created software that reads data from our clinical treatment planning system and renders the plan on a life-size “virtual linear accelerator.” The patient’s CT simulation data is converted into a 3D translucent virtual human shown lying on the treatment table while visible yellow radiation beams are delivered to the target volumes in the patient. We conducted a prospective study to determine if showing patients their radiotherapy plan in VR improves patient education and/or reduces anxiety about treatment. A total of 43 patients were enrolled. The most common plans were 3D breast tangents and intensity-modulated radiotherapy prostate plans. Patients were administered pre- and post-experience questionnaires. Thirty-two patients (74%) indicated that they “strongly agree” that the VR session gave them a better understanding of how radiotherapy will be used to treat their cancer. Of the 21 patients who expressed any anxiety about radiotherapy beforehand, 12 (57%) said that the VR session helped decrease their anxiety about undergoing radiotherapy. In our single-institution, single-arm prospective patient study, we found that the majority of patients reported that the personalized VR experience was educational and can reduce anxiety. VR technology has potential to be a powerful adjunctive educational tool for cancer patients about to undergo radiotherapy.

Watt-level, ultrafast, tunable yellow source based on single-pass, fourth-harmonic generation of Cr2+:ZnS laser at 2360 nm.

We report a compact source of high power, tunable, ultrafast yellow radiation using fourth-harmonic generation of a mid-IR laser in two-stage frequency-doubling processes. Using Cr2+:ZnS laser at 2360 nm frequency-doubled in a multi-grating MgO:PPLN crystal, we have generated near-IR radiation tunable across 1137-1200 nm with average output power as high as 2.4 W and pulse width of ∼60fs. Subsequently, the near-IR radiation is frequency-doubled using a bismuth triborate (BIBO) crystal to produce coherent yellow radiation tunable across 570-596 nm with a maximum average power of ∼1W. The source has a maximum mid-IR to yellow (near-IR to yellow) single-pass conversion efficiency as high as ∼29.4% (∼47%). Without any pulse compression, the yellow source has output pulses at a repetition rate of 80 MHz with a pulse width of ∼130fs in Gaussian-shaped and a spectral width of ∼4nm corresponding to a time-bandwidth product of 0.45. The generated output beam has a Gaussian transverse beam profile with measured M2 values of Mx2∼1.07 andMy2∼1.01.

The Effect of Various ZnO Layer towards Sensing Performance as an Electrolyte-Insulator-Semiconductor pH Sensor

Multilayers zinc oxide thin films were synthesized by the sol–gel spin coating process to fabricate sensing membranes in an electrolyte-insulator-semiconductor (EIS) sensor for pH detection. The effect of various layers (single, three and five layers) on the crystallinity, morphological and optical properties of ZnO films were investigated by XRD, FE-SEM, and Photoluminescence respectively. The ZnO thin films grown were polycrystalline with hexagonal wurtzite structure. The films were not smooth, with grains and porosity in between them, and become denser as film thickness increased. The PL spectra exhibit two main emission peaks at near band edge 360-380 nm region (strong and sharp UV radiation) and 450–600 nm region (broad blue, green, and yellow radiation). Sensitivity, linearity was measured to determine the sensing and reliability performance of fabricated devices. The result confirmed that, the sensitivity for the three samples increased with increased layer from 48.3 mV/pH to 82.58 mV/pH. Compared to single and three layers of the ZnO electrolyte-insulator-semiconductor (EIS), ZnO grown with five layers exhibits a higher sensitivity of 82.58 mV/pH in solutions from pH 2–12 and linearity of 99.015 %. This is due to the increased of ZnO thickness, which produces dense surface and a well-crystallized grain structure.

39. Dosimetric study of medical staff for selective internal radiation therapy using 90Y glass microsphere for the treatment of hepatic cancer

Introduction Selective internal radiation therapy using 90Y glass microsphere is a treatment dedicated to non-resectable hepatic tumours. This technique requires two imaging modalities, interventional radiology and scintigraphy and handling of two radionuclides. The aim of this work is to assure a safe delivery of this therapy by establishing an average effective dose and an equivalent dose to the extremities for the involved staff for the entire process. Methods Our study was focused on 5 operators: a radiologist, a nuclear doctor, a radiopharmacist, an interventional radiology (IR) manipulator and a nuclear medicine (NM) manipulator. We considered two phases: the work-up phase that consisting of injecting 99mTc to check patient eligibility, and the treatment phase with 90Y microspheres delivery. For both phases, radiopharmaceutical preparation and scintigraphy were performed in the NM department. Three exposure sources were considered: radioscopy, radiography and radionuclides during preparation and injection. The dosimetric evaluations were performed for 5 consecutive patients. Cumulative effective and equivalent (extremities) doses were estimated by dose rate (scopy) and dose (graphy) measurements with an AT1123 radiometer. An Unfors NED dosimeter was used for cumulative hands dose during radioactive source manipulation. Regarding the zoning of operating room, the cartography of cumulative dose carried out for each step. Results For the entire process, considering all phases and exposition modes, the thorax effective dose (without taking into account the shielded apron) was 1.6 μSv for the NM manipulator, 9.1 μSv for the IR manipulator, 1 μSv for the nuclear physician and the radiopharmacist and 21.9 μSv for the radiologist. The equivalent hands dose was 358.4 μSv for the NM manipulator, 3.7 μSv for the nuclear physician, 63.4 μSv for the radiologist and 2.2 μSv for the radiopharmacist. A yellow controlled zone was applied for all the areas of the operating room due to total cumulative doses of 147 μSv and 90 μSv at 1 m from the patient for work-up and treatment respectively. Conclusion This “operator maximum dose” study suggests that the radiologist and the NM manipulator receive significant exposure on their hands. However it is completely compatible with the personal radiation ranking due to a limited number of RIS performed per year. The determined yellow radiation controlled area is applied to both work-up and treatment phases.

Sodium D2 resonance radiation based on intracavity sum-frequency-mixing laser operation in Nd:GdVO4–Nd:YLiF4 crystals

We present a laser architecture to obtain continuous-wave orange–yellow radiation at 589 nm. A 808 nm diode-pumped the Nd:GdVO4 crystal emitting at 1341 nm. A part of the pump power was then absorbed by the Nd:GdVO4 crystal. The remainder was used to pump the Nd:YLiF4 (Nd:YLF) crystal emitting at 1053 nm. Intracavity sum-frequency-mixing at 1341 and 1053 nm was then realized in a LiB3O5 (LBO) crystal to produce orange–yellow radiation. We obtained a continuous-wave output power of 352 mW at 589 nm with a pump laser diode emitting 18.4 W at 808 nm.

Studies on the spectral purity of copper–hydrogen bromide laser radiations

This paper presents, for the first time to the best of our knowledge, the linewidth, frequency, and stability characteristics of a copper-HBr laser. These spectral purity attributes were found to be critically linked with the electrical input power and HBr concentration, unlike that of the optical resonator. Variation in green and yellow radiation linewidths from 4 to 4.5GHz and from 6.5 to 8.8GHz, linewidth fluctuations from 50 to 150MHz and from 60 to 530MHz as well as frequency fluctuations from 10 to 100MHz and from 410 to 10MHz were observed when varying the input power and HBr concentration. These results are comprehensively analyzed in terms of isotopic shift, hyperfine splitting, line broadening, and temperature and gain distribution effects relevant to this laser.

Effect of pulse to pulse variation of divergence, pointing and amplitude of copper vapor laser radiations on their second harmonic and sum frequency conversion

This paper presents the effect of single pulse stability of divergence angle, beam pointing angle and amplitude of green and yellow radiation pulses of an unstable resonator copper vapor laser (CVL) oscillator in the sum frequency (SF) mixing and second harmonic (SH). The conversion efficiency of sum frequency generation was lower compared to second harmonic processes despite larger fundamental power being used in sum frequency experiments. However the net UV power obtained at the sum frequency was higher than both of the second harmonic UV frequencies. Lower sum frequency generation (SFG) conversion efficiency compared to second harmonic generation (SHG) of individual CVL radiation is attributed to difference in single pulse stability of beam pointing, divergence and amplitude fluctuation of both CVL radiations in addition to commonly known fact of spatio-temporal mis-match. At the same fundamental input power, higher SH conversion efficiency of yellow compared to green is attributed to its better single pulse stability of beam pointing and divergence.

Formation of Lean Premixed Surface Flame Using Porous Baffle Plate and Flame Holder

A lean premixed surface flame has many advantages including low CO(Carbon Monoxide) and NOx(Nitrogen Oxide) emission and applicability of a small combustion volume leading to compact design. These advantages make it applicable to burner for condensing boilers with high thermal efficiency. Moreover recent severe regulation of global warming gas favored a lean premixed surface flame in development of a condensing boiler burner. This study focused on emission characteristics of lean premixed flame and the effect of flow distribution on flame stability of a surface flame in a cylindrical porous metal plate burner. For conceptual design of surface flame burner, the numerical calculation of a flow pattern inside the burner was performed and the calculated data were used for design of the burner system including the baffle plate and flame holder. The results show that the surface and stable premixed flame can be generated by implementing the proper baffle plate and flame holder. The surface cylindrical flame mode is changed into green flame, yellow radiation flame, blue flame and blow off with decreasing equivalence ratio. The blue flame has a wide stability region in the stability curve and showed the lowest CO and NOx emission at low equivalence ratio. And CO decreased as the mixture ratio became leaner but NOx showed almost the same emission level. For stability of a surface cylindrical flame, it was found to be very important to select the proper distribution of holes in a baffle plate and install the flame holder to prevent blow off at the rim of the cylindrical burner. NOx was measured below 6 ppm (0% oxygen base) from equivalence ratios 0.706 to 0.769 through the proper design of baffle plate and flame holder. CO which is a very important emission index in residential gas boiler was observed below 49.1ppm under the same equivalence ratio range.

Studies on the effect of instability of divergence, pointing and amplitude of green and yellow radiation pulses of copper vapour laser in second harmonic and sum frequency conversion

This paper presents the effect of single pulse stability of divergence angle, beam pointing angle and amplitude of green and yellow radiation pulses of an unstable resonator copper vapour laser (CVL) oscillator in the sum frequency mixing and second harmonic. The conversion efficiency of sum frequency generation was lower compared to second harmonic processes despite larger fundamental power being used in sum frequency experiments. However the net UV power obtained at the sum frequency was higher than both of the second harmonic UV frequencies. Lower SFG conversion efficiency (12.4%—271nm) compared to SHG (16.7%—255nm, 14.5%—289nm) of individual CVL radiations is attributed to difference in single pulse stability of beam pointing, divergence and amplitude fluctuation of both CVL radiations in addition to commonly known fact of spatio-temporal mis-match. At the same fundamental input power (2.7W), higher SH conversion efficiency of yellow (12.7%) compared to green (11.0%) is attributed to its better single pulse stability of beam pointing and divergence.

An intracavity frequency doubled H_2 Raman laser scheme for generating narrow-linewidth yellow radiation

We propose a cavity-based combined Raman and second harmonic generation scheme for generating hundreds of milliwatts of continuous-wave yellow radiation with a frequency linewidth suitable for spectroscopic applications. We suggest using H2 gas as the Raman medium in an external Raman ring resonator with an intracavity frequency doubling crystal. Using gas rather than a crystal allows for single-mode, narrow-linewidth operation suitable for many spectroscopic applications. In a specific numerical example, we predict the generation of more than 200 mW of narrow-linewidth 583 nm light from an input of 1 W of 785 nm light, which could be obtained from a low cost tapered amplifier diode system. Finally, we suggest methods for improving the laser performance.

Birefringence and dichroism of poly(vinyl-alcohol) foils containing phthalazinium ylids

Pure and colored with phthalazinium ylids poly(vinyl-alcohol) (PVA) foils were stretched under gentile heating. The birefringence of the thin foils was determined with a Babinet compensator standardized for yellow radiation of a Sodium lamp. The determined birefringence of the colored PVA foils is higher than that of the pure PVA foils. This fact indicates that the phthalazinium ylids facilitate the increase in the anisotropy of the stretched foils. The visible absorption electronic band of phthalazinium ylids was used to estimate the dichroic ratio and the degree of order of the ylid molecules in the stretched PVA foils. An increase in dichroism and birefringence with the degree of stretching has been evidenced for uncolored and colored PVA foils.

7.4 W yellow GaInNAs-based semiconductor disk laser

A high power frequency-doubled semiconductor disk laser emitting 7.4 W of output power at the yellow wavelength range is reported. Fundamental emission at around 1190 nm was achieved using a high quality gain mirror incorporating GaInNAs quantum wells. The infrared radiation was frequency doubled using an intracavity beta barium borate crystal. To the best of the authors knowledge, this is the highest output power reported for a single-chip semiconductor disk laser emitting yellow radiation.

An unusual 3D complex showing 5,8-connected topology with encapsulated 8-connected octamolybdate polyoxoanions

Abstract An unprecedented inorganic–organic framework, containing octamolybdate polyoxoanions as 8-connected nodes, defines a new 5,8-connected topology and represents 8-fold interpenetrated srs (SrS2) topological Cu(I)-organic secondary network for the first time. While the free bipy ligand displays weak luminescence in the solid state at room temperature, this compound exhibits an intense yellow radiation emission maximum at λ ≈ 567 nm upon excitation at λ ≈ 365 nm.

Interferometric method for birefringence determination with a polarizing microscope

We present a new mathematical technique which can be used to determine the main refractive indices and the birefringence of an anisotropic layer by using a polarizing microscope in conoscopic illumination. The values of the birefringence for the yellow radiation of a Na lamp are determined here for a Carpathian quartz sample, but the technique can also be applied to the study of other uniaxial substances such as liquid crystals, model membranes or biological tissues. The validity of the proposed method was tested by comparing the results with those obtained with a Rayleigh interferometer and by using the technology of channeled spectra.

The Influence of Radiation Quality on the in vitro Rooting and Nutrient Concentrations of Peach Rootstock

The effect of radiation quality (350 - 740 nm) and darkness (D) on in vitro rooting, and chemical composition of the peach rootstock GF 677 was studied. Shoot explants were exposed for four weeks to cool white (control) (W), red (R), blue (B), green (G) or yellow (Y) radiation from fluorescent tubes. Some of the explants were kept in D during the rooting stage and others were maintained only for the first 2- or 4-d under R, B, G, Y or D, and subsequently were transferred to W. W was the most effective radiation source for adventitious root formation of GF 677 explants. Rooting was inhibited in those plants that remained in continuous D, and R reduced root growth in all treatments. The 2- or 4-d exposure to D, Y or B followed by W helped adventitious root development similarly as did W. G significantly increased Fe concentration in roots.

Regulation of Photosynthesis by Radiation Quality in the Lichen Evernia prunastri

In Evernia prunastri, photosynthetic gas exchange was saturated with yellow radiation (SOX) at 400 μmol m-2s-1, and then red (R), far-red (FR), or blue (B) radiations at irradiance of 15 μmol m-2s-1 were added. Because of photosynthesis saturation, any stimulation or decay in CO2 assimilation by any radiation quality could be attributed to the involvement of a non-photosynthetic photoreceptor. Thus CO2 assimilation, effective quantum yield, and photochemical quenching were enhanced when R was included, and decreased with FR. Blue radiation completely abolished CO2 fixation. Hence different spectral radiation qualities may activate non-photosynthetic photoreceptors such as phytochrome and blue photoreceptors, which are involved in regulating the photosynthetic activity in E. prunastri.

Role of defect centers in recombination processes in GaN monocrystals

A confocal fluorescence microscopic study was carried out on GaN monocrystals grown by molecular beam epitaxy and doped with Mn. The samples were irradiated with mid band gap radiation (488 nm) rather than ultraviolet, and it was found that a strong yellow radiation was emitted by defect centers. Three-dimensional images clearly reveal not only the size and the form of the illuminating defect centers but also their orientations with respect to the plane on which these defects were grown. This is a direct evidence for the radiative recombination at the defect centers when excited by the midgap radiation.

Influence Of Ti Related Centers On ZnSe Radiation Spectra

AbstractZnSe annealed in (Zn + 46 wt.% TI) vapors and in Zn melt with 5 wt.% TI addition was investigated. The radiation spectra in the regimes of stationary and pulsed photoluminescence (PL) with the time delaying at 77K were studied. By using coloured cathodoluminescence (CCL) combined with the crystal cleavage image in the secondary electrons reflection the impurities and defects volume distribution was evaluated. It was revealed that at the annealing of ZnSe crystals in TI vapors, the cleavage surface has light blue radiation on the red background with an homogeneous field distribution with the dimensions ˜ 1..10μm. On the edge of the cleavage on the depth of 10μm the region of yellow radiation is observed. At the annealing in the melt the irradiation became blue on a weak red background, the homogeneity enhances. At the room temperature PL spectra correspond with images of cleavage in CCL. In the PL (at 77K) spectra in the exciton region there were observed: bands at 445nm (blue radiation); edge radiation at 460nm, 485nm with the LO phonons replica (blue region) and in the impurity region: bands 500...570nm (yellow-green radiation); 600...700nm and 720...800nm (red radiation). The investigation of PL of the annealed samples surface allowed the suppose, that the bands at 2,76eV (450nm), are stipulated by the free-bound transition on the acceptor center (E + 40meV), including TI.The comparison of ion and tetrahedronical covalent radiuses of Zn, Se and TI, electronegativity, probability of Zni and Vse. formation at the annealing allowed to suppose that, TI fills Vse. and forms (Zni Tls) and (Vse. Tlse) complexes. The carried out theoretical calculations according to the model of two-atom molecule gives the energy of complexes occurrence (Ev + 0,04) eV and (Ev + 0,8) eV. The first value accordingly is in good agreement with the experimental data.