Double-beam Spectrometer Research Articles

Study of petrol degrading bacteria and screening for biosurfactants

Petroleum-based products when mixed with soil, air and water can lead to environmental pollution which can be dangerous for humans. In the current study, soil samples from the petrol unloading area of a petrol pump were collected and nine isolates of petrol degrading bacteria were isolated from the soil by enrichment technique using Bushnell and Hass media. The isolated bacteria could degrade up to 5% petrol and the best degraders were chosen after evaluating their cell mass when grown in the presence of petrol. The percentage of petrol degraded after different intervals of incubation was compared using a UV-vis double beam spectrometer at 228 nm. It was found that the two bacteria - Pseudomonas aeruginosa and Burkholderia cepacia degraded petrol 94.96% and 94.74%, respectively, by day 15 of incubation. The percentage degradation gradually decreased by day 20. Both bacteria were also screened for the production of biosurfactants through haemolysis. It was found that both the bacteria could produce biosurfactant along with them being a potent petrol degrader.

Gold-Nanoparticle Synthesization In Gum Arabic Solution By Pulsed Laser Ablation

Green synthesis of nanoparticles is crucial to effectively reduce the risk to the environment by eradicating hazardous components that are harmful to human health. The broad complications such as aggregation and oxidation of nanoparticles will potentially limit their usage. Gum Arabic (GA) has attained decent attention due to less toxicity and bio-compatibility with metals. Gold-nanoparticles (Au-NPs) have several applications in diagnosing cancer, targeted delivery of drugs and in cancer treatment. This project is conducted by synthesizing Au-NPs in GA solution via pulsed laser ablation in liquid (PLAL) technique at varied laser fluences. A Q-switched Nd:YAG laser with wavelength of 1064 nm was focused using a lens with a focal length of 80 mm to ablate a gold plate immersed in GA solution. Four different laser fluences were tested. The laser fluences were 0.203, 0.214, 0.250 and 0.272 J. The Au-NPs synthesized in the GA solution were then characterized using photoluminescene (PL) and UV-Visible double beam spectrometer (UV-Vis). The highest laser fluence has shown the highest intensity while the wavelength of all peaks is the same indicating the same nanomaterials being synthesized in each sample. The UV-Vis spectra indicated that the absorbance increases as the holding time is prolonged. It is believed that the formation of Au-NPs is a nucleating process and followed by a growing process.

Fabrication and Characterization of High-Quality UV Photodetectors Based ZnO Nanorods Using Traditional and Modified Chemical Bath Deposition Methods

Ultraviolet (UV) photodetectors (PDs) based on high-quality well-aligned ZnO nanorods (NRs) were fabricated using both modified and conventional chemical bath deposition (CBD) methods. The modified chemical bath deposition (M-CBD) method was made by adding air bubbles to the growth solution during the CBD process. The viability and effectiveness of M-CBD were examined by developing UV PDs based on ZnO NRs. The ZnO nano-seed layer was coated on a glass substrate utilizing radiofrequency (RF) sputtering. The impact of the different growth-times on morphology, growth rate, crystal structure, and optical and chemical properties were investigated systematically using different characterization techniques, such as field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) analysis, UV–VIS double beam spectrometer, and energy dispersive X-ray analysis (EDX), respectively. The Al/ZnO UV PDs based on ZnO nanorods were fabricated with optimum growth conditions through the two methods of preparation. This study showed that the synthesized ZnO NRs using the M-CBD method for different growth times possess better properties than the conventional method under similar deposition conditions. Despite having the highest aspect ratio and growth rate of ZnO NRs, which were found at 4 h growth duration for both methods, the aspect ratio of ZnO NRs using the M-CBD technique was comparatively higher than the conventional CBD method. Besides, the UV PDs fabricated by the M-CBD method at 5 V bias voltage showed high sensitivity, short response time, quick recovery time, high gain, low dark current, and high photocurrent compared with the UV PD device fabricated by the conventional CBD method.

Thermal annealing induced tunable localized surface plasmon resonance of Au/Ag bimetallic thin film

Abstract Tunable localized surface plasmon resonance (LSPR) was achieved on thermally annealed thin films composed of Au deposited on Ag. Characterization of the crystallographic structure, morphology, and optical properties of the thin films was done by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), UV–VIS-NIR double-beam spectrometer, and Raman system. The XRD results confirmed that thermal annealing improved the grain growth and orientation of Au/Ag bimetallic thin films. AFM and SEM results showed that Au/Ag bimetallic thin films transformed into Au/Ag ellipsoid nanoparticles (NPs) on thermal annealing. The LSPR wavelength of Au/Ag NPs could be tuned between 500 nm and 342 nm. Additionally, the Raman scattering could be adjusted by increasing the thickness of Ag in the Au/Ag bimetallic composite structure.

ITO induced tunability of surface plasmon resonance of tin thin film

A low-cost tin thin film with different thicknesses was deposited on ITO covered silica substrates via magnetron sputtering. The structure, surface morphology, and optical properties of tin/ITO thin films were investigated via X-ray diffraction (XRD), atomic force microscopy (AFM), UV–VIS-NIR double beam spectrometer, and Raman system, respectively. The results show that by controlling the thickness of the tin thin film with ITO, red shift of the surface plasmon resonance wavelength was achieved and the surface-enhanced Raman scattering (SERS) was enhanced. On the contrary, when no ITO layer was employed in the system, the variation of the tin film thickness did not cause a significant change in the resonance wavelength. Additionally, Finite-Difference Time-Domain (FDTD) was performed for the surface plasmon resonance properties of the samples, and the simulation results were consistent with the experiments.

Laser induced the tunable permittivity of Epsilon-Near-Zero induced in indium tin oxide thin films

Abstract Tunable permittivity of Epsilon-Near-Zero (ENZ) of ITO thin films were realized by Nd: YAG pulse laser irradiation. The effects of different pulsed laser power irradiation on the structure, morphology and optical properties of the samples were investigated via X-ray diffraction, atomic force microscopy, UV-VIS-NIR double beam spectrometer, spectroscopic ellipsometry and Raman system, respectively. Those results indicate that pulse laser irradiation has the effects on the preferential orientation and the permittivity wavelength region of ENZ from 1137 to 2001 nm. The variations of Raman spectra further confirms that the laser irradiation can induce some defects driving the special optical characteristics of ITO films. In addition, the results of Finite-Difference Time-Domain are in good agreement with those of the experiments.

Laser detection of nuclear spin isomers of ethylene molecules

We report the making of a double-beam laser spectrometer to measure absorption spectra in the ν5 + ν9 combination vibrational band of ethylene in the region of λ = 1.6 μm. The spectrometer is used to find a portion of the spectrum that has well-resolved absorption lines of all four nuclear spin isomers of ethylene molecules. The rotational quantum numbers of these absorption lines and the nuclear spin isomers of ethylene molecules responsible for them are identified.

Dependence of the magnetic and optical properties of Ni-Co nanoferrite on the particle shape

This work presents the effect of particle shape on the magnetic and optical properties of Ni-Co nanoferrite (NCF). Two series of different preparation methods were used to obtain two different shapes of NixCo1-xFe2O4 where x=0, 0.25, 0.5, 0.75 and 1. Sol gel was the first method used to synthesize NCF with citric acid as a fuel and the second series was synthesized by hydrothermal route and the fuel was oxalic acid. Structural characterization for NCF nanomaterials was carried out by X-ray diffraction (XRD), Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscope (TEM). Magnetic parameters were determined from Vibrating Sample Magnetometer (VSM) for all samples and it is noticed that the values of Mr and Mr/Ms are greater in nanorod series than nanosphere series. RLC Bridge was used to obtain the Curie temperature of the polycrystalline nanomaterials by the variation of relative permeability with increasing temperature. Values of direct and indirect band gaps were determined from double beam spectrometer using Diffused Reflectance Spectroscopy (DRS) measurements. It was found that changing particle shape could change the cation distribution, magnetic and optical properties of NCF nanoparticles.

The influence of dielectric environment on the localized surface plasmon resonance of silver-based composite thin films

Ag-based thin films with different topography were prepared by annealing process and laser irradiation, respectively. The tunability of localized surface plasmon resonance (LSPR) was realized by adjusting the cover layer thickness of ITO or TiO2. The effect of dielectric environment of Ag-based composite thin films on structure, surface morphology and optical property was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), UV-VIS-NIR double beam spectrometer and Raman system, respectively. With the thickness of dielectric layer increasing, the topography of as-irradiated Ag-based thin films became smoother while the as-annealed Ag-based thin films had a rougher surface. LSPR absorption of both ITO/Ag and TiO2/Ag bilayers showed red shift with the thickness of dielectric layer increasing. The electromagnetic field coupling between dielectric layers and Ag thin films contributed to increase significantly the sensitivity of surface enhanced Raman scattering (SERS). Additionally, the result of finite-difference time-domain (FDTD) simulation was in good agreement with that of the experiment.

"Synthesis and Optical Properties of Polystyrene Doped with DCM Thin Films "

"In the present work Polystyrene (PS) polymer doped with DCM laser dye thin films have been prepared on glass substrate using casting method. The final samples of PS doped with DCM thin films were treated with different annealing temperatures at (30, 40, 50, 60) oC. Optical absorption and transmission spectra of the prepared thin films were recorded using UV-VIS double beam spectrometer in the wavelength range from 190 to 1100 nm. The results shown that the allowed direct electronic transitions energy gap increased from 2.08 up to 2.25e.V as the temperature increasing from 30 to 60oC, whereas the allowed indirect electronic transition energy gap increase from 2.02 up to 2.17 eV as the temperature increase from 30 to 60oC. The effect of temperature on the optical properties such as Urbach’s energy, Refractive index, Extinction coefficient, Critical angle, Brewster angle, and Finesse coefficient of PS doped with DCM thin films also studied in this work.

Laser irradiation induced tunable localized surface plasmon resonance of silver thin film

Tunable localized surface plasmon resonance (LSPR) properties of silver thin films were realized by CO2 laser irradiation. The effects of laser irradiation on the structure, morphology and optical property of the samples were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), UV-VIS-NIR double beam spectrometer and Raman system, respectively. XRD patterns show that laser irradiation has the effects of improving grain growth and orientation of Ag thin films. With laser irradiation power increasing, the topography of as-irradiated silver thin films were observed to develop discontinuous nano-ellipsoid structure with a red-shift of the surface plasmon resonance wavelength in visible region. Both the various ellipsoid sizes and the states of aggregation of as-irradiated silver thin films contributed to increase significantly the sensitivity of surface enhanced Raman scattering (SERS). Additionally, the simulation result of Finite-Difference Time-Domain (FDTD) was proved to be in good agreement with that of the experiment.

Microstructure, magnetic, optical and catalytic activity of Li–Co–Cd nanoferrites

Nanoparticles of Lithium mixed ferrite of the chemical formula Li0.1 (Co1 − x Cdx)0.8 Fe2.1O4; x = 0.0, 0.2, 0.4, 0.6 and 0.8, had been successfully prepared by sol–gel technique. Samples were structurally characterized by X-ray diffraction, Energy dispersive spectroscopy, Transmission Electron Microscope and Fourier Transform infra-red spectroscopy. From vibrating sample magnetometer measurements, saturation magnetization and coercivity were determined. The saturation magnetization and coercive field, generally, decreased with x. The Curie temperature Tc is determined through the change of relative permeability with temperature. The direct energy gap values for the synthesized samples were determined from the diffused reflectance spectroscopy measurements using double beam spectrometer. In order to study the oxidation of methylene blue, H2O2 and nanopowder of ferrites were added to the aqueous solution of MB with stirring and the efficiency of the catalyst was evaluated.

Electron-beam irradiation induced optical transmittance enhancement for Au/ITO and ITO/Au/ITO multilayer thin films

Electron beam (EB) irradiation experiments on Au/ITO and ITO/Au/ITO multilayer thin films are reported. The structure and the optical-electrical properties of the samples were investigated by X-ray diffraction, atomic force microscopy, four-point probe resistivity measurement system, and UV–vis-NIR double beam spectrometer, respectively. Those results show that the EB irradiation has the effects of improving the crystalline of samples, widening the optical band gap of both thin films, reducing the sheet resistance, and improving the transmittance of samples.

Electron-beam irradiation induced phase transformation, optical absorption and surface-enhanced Raman scattering of Indium tin alloy thin films

Electron beam (EB) irradiation experiments on Indium-tin (In-Sn) alloy thin films are reported. The structure and the optical properties of the samples were investigated by atomic force microscopy, X-ray diffraction, UV-vis-NIR double beam spectrometer and Raman system, respectively. Those results show that EB irradiation has the effects of changing the preferred orientation, improving the crystalline, enhancing the absorption, and improving the surface-enhanced Raman scattering (SERS) of samples. In addition, Finite-Difference Time-Domain (FDTD) was performed for the surface plasmon resonance properties of the as-irradiated samples, and the results are in good agreement with the experiments.

The effect of injective application of selenopyran on the prolonged increase of the selenium content in blood and sperm of rams

Selenium is a microelement of big importance for male reproduction. As a part of the antioxidative enzyme gluthationperoxidase and structural Se proteins, it plays pivotal role in the defense of spermatozoa against generated ROS and in ensuring of its motility. During the last years the interests to the organic forms of selenium was enhanced because of its better biological utilization. The present work aimed to study the effect of injective application of organic compound selenopyran in rams on the distribution of selenium content in blood and sperm and on the changes in sperm quality. The experiment was conducted with 5 rams from the Synthetic Population Bulgarian Milk breed at the age between 3-7 years and live weight 85-90 kg. The animals were injected once with an oil solution of the selenopyran in dose of 0.1mg/kg live weight (selenium content 24%) 45 days before starting the breeding season. The blood was collected before treatment and 45 days thereafter. At the same time the first and second ejaculates of rams were collected using artificial vagina and analyzed by Sperm Class Analyzer. The selenium content was measured in plasma, blood cells and sperm by atomic absorption spectrometry using SpectrAA 55B double beam spectrometer (Varian, Inc.). The results showed that one injection of organic compound of selenium - selenopyran in dose of 0.1mg/kg live weight ensured the increase and support of high level of selenium in blood (plasma and blood cells) and in sperm during investigated period. That lead to the proper spermatogenesis in testis and allowed the production of qualitative ejaculates with higher number of total spermatozoa as well as of spermatozoa with progressive motility.

Pressure Broadening of the Cadmium 326.1 nm Line

The temperature dependence of the Cd line absorption profile at 326.1nm perturbed by inert gases (Xe, Kr, Ar, Ne and He) has been carefully studied over a wide spectral range in both blue and red wings using a high-resolution double-beam spectrometer. The atomic densities of inert gases (Ngas) and cadmium (NCd) was sufficient to study the wing of the Cd line at 326.1nm. The temperature dependence of the studied line profile was analyzed in the framework of the quasi-static theory. The van der Waals coefficient differences (ΔC60 and ΔC61) between the ground X0+ state and the two excited states A30+ and B31 were obtained from the near red wing profile using Kuhn's law. All the results of the well depths with their positions for the ground (X0+), and the excited (31, 30+) were determined. The obtained results are compared with the corresponding theoretical and experimental molecular beam experiments results.

Interatomic potentials for Cd–Cd and Cd–inert gases system (Xe, Kr, Ar, Ne and He) by studying the profile of Cd line 326.1 nm

The temperature dependence of the Cd line absorption profile at 326.1nm perturbed by inert gases (Xe, Kr, Ar, Ne and He) has been carefully studied over a wide spectral range in both blue and red wings using a high-resolution double-beam spectrometer. The atomic densities of inert gases (Ngas) and cadmium (NCd) were sufficient to study the wing of the Cd line 326.1nm. The temperature dependence of the studied line profile was analyzed in the framework of the quasi-static theory. The van der Waals coefficient differences (ΔC60 and ΔC61) between the ground X0+ state and the two excited states A30+ and B31 were obtained from the near red wing profile using Kuhn׳s law. All the results of the well depths with their positions for the ground (X0+), and the excited (A30+, B31) states were determined. The comparison between the obtained results and the corresponding theoretical and experimental molecular beams experiments was presented.

双光束微型光谱仪

A novel miniature double-beam spectrum measurement system called double-beam miniature spectrometer is proposed based on twin-core fiber and 2-D CCD detector Czerny-Turner spectrometer.The advantage of the miniature spectrometer with small size and fast measurement and the superiority of the double-path spectrophotometer with double light paths are both presented.In this system,the light intensity of the light source is divided equally into two parts by the first two-core fiber.One part is considered as the reference light path,and the other is considered as the sample light path.Then the reference light and the sample light are transferred to the slit of the spectrometer by the second two-core fiber.The two cores of the second two-core fiber are distributed along the direction of the length of the slit(the direction of the nondispersion).In order to avoid the overlapping and the crosstalk between the sample spectrum and the reference spectrum,astigmatism corrected cylindrical lens is added into the symmetrical crossed Czerny-Turner optical bench.The optical design software is used to optimize the system aberration.The ray tracing result shows that the imaging spectra of the reference path and the sample path can be clearly distinguished in the wavelength range of 300～800nm.Eventually,the experimental prototype of the double-beam miniature spectrometer is manufactured and aligned.The sample spectrum and the reference spectrum can be displayed and measured simultaneously with the system.The design method of the double-beam miniature spectrometer is verified by the experiment.The light path of double beam,the characteristic of fiber connector and flexible configuration are realized in the double-beam miniature spectrometer.

Thiol-disulfide Redox Dependence of Heme Binding and Heme Ligand Switching in Nuclear Hormone Receptor Rev-erbβ

Rev-erbβ is a heme-binding nuclear hormone receptor that represses a broad spectrum of target genes involved in regulating metabolism, the circadian cycle, and proinflammatory responses. Here, we demonstrate that a thiol-disulfide redox switch controls the interaction between heme and the ligand-binding domain of Rev-erbβ. The reduced dithiol state of Rev-erbβ binds heme 5-fold more tightly than the oxidized disulfide state. By means of site-directed mutagenesis and by UV-visible and EPR spectroscopy, we also show that the ferric heme of reduced (dithiol) Rev-erbβ can undergo a redox-triggered switch from imidazole/thiol ligation (via His-568 and Cys-384, based on a prior crystal structure) to His/neutral residue ligation upon oxidation to the disulfide form. On the other hand, we find that change in the redox state of iron has no effect on heme binding to the ligand-binding domain of the protein. The low dissociation constant for the complex between Fe(3+)- or Fe(2+)-heme and the reduced dithiol state of the protein (K(d) = ∼ 20 nM) is in the range of the intracellular free heme concentration. We also determined that the Fe(2+)-heme bound to the ligand-binding domain of Rev-erbβ has high affinity for CO (K(d) = 60 nM), which replaces one of the internal ligands when bound. We suggest that this thiol-disulfide redox switch is one mechanism by which oxidative stress is linked to circadian and/or metabolic imbalance. Heme dissociation from Rev-erbβ has been shown to derepress the expression of target genes in response to changes in intracellular redox conditions. We propose that oxidative stress leads to oxidation of cysteine(s), thus releasing heme from Rev-erbβ and altering its transcriptional activity.

Influence of deposition parameters and heat treatment on the NO 2 sensing properties of nanostructured indium tin oxide thin film

Highly oriented and transparent indium tin oxide (ITO) films have been deposited onto glass substrates by radio frequency magnetron sputtering at 648 K, under an oxygen partial pressure of 1 Pa. The effect of the sputtering power and annealing was studied. Transmission was measured with a double beam spectrometer and electrical analysis using four probe and Hall effect setup. Structural characterization of the films was done by X-ray diffraction. Characterization of the coatings revealed an electrical resistivity below 6.5 × 10 − 3 Ω cm. The ITO films deposited at 648 K were amorphous, while the crystallinity improved after annealing at 700 K. The optical transmittance of the film was more than 80% in the visible region. The surface morphology examined by scanning electron microscopy appears to be uniform over the entire surface area, after annealing. The NO 2 sensing properties of the ITO films were investigated. At a working temperature of 600 K, the ITO sensor showed high sensitivity to NO 2 gas, at concentrations lower than 50 ppm.