scholarly journals Synthesis of CdSe/ZnS Nanoparticles with Multiple Photoluminescence

2020 ◽  
Vol 21 (1) ◽  
pp. 105-112
Author(s):  
T. K. Sliusariak ◽  
Y. M. Andriichuk ◽  
S. A. Vojtovych ◽  
M. A. Zhukovskyi ◽  
Y. B. Khalavka
Keyword(s):  
Cadmium Selenide ◽  
Shell Growth ◽  
Inert Atmosphere ◽  
Zinc Stearate ◽  
Visible Range ◽  
Effective Diameter ◽  
Cadmium Complex ◽  
Zns Nanoparticles ◽  
Wide Range ◽  
Wave Emission

The CdSе/ZnS nanostructures of Core-Shell type, that have multi-wave emission, are described and a scheme of possible energy transitions in the studied system is presented. CdSe nuclei were synthesized by mixing cadmium and selenium precursors without creating an inert atmosphere. The cadmium complex with sulphanilamide was used as a cadmium precursor and simultaneously as a stabilizing ligand. To grow the shell, zinc stearate and thiourea were gradually added to the solution of cadmium selenide nuclei in octadecene at 200°C. TEM studies show that the obtained CdSe/ZnS nanoparticles have the shape close to tetrahedral with an effective diameter up to 10 nm. The thickness of the ZnS shell is about 3-4 nm. From the absorption spectra of the CdSe/ZnS nanoparticles, it is clear that the shell growth leads to a sharp increase in the absorption in the short wavelentgh area, which means the formation of a wide gap ZnS material. The obtained CdSe/ZnS nanostructures emit three fluorescence peaks in the visible range. They are attributed to exciton transitions in the nucleus, recombination at defects of the boundary between the core and the shell, and recombination at defects of the shell. Such property provides CdSe/ZnS nanocrystals with a wide range of functionalities.

scholarly journals A coma-free super-high resolution optical spectrometer using 44 high dispersion sub-gratings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hua-Tian Tu ◽  
An-Qing Jiang ◽  
Jian-Ke Chen ◽  
Wei-Jie Lu ◽  
Kai-Yan Zang ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Wavelength Region ◽  
Ultra Violet ◽  
High Spectral Resolution ◽  
Visible Range ◽  
High Dispersion ◽  
Charge Coupled Device ◽  
Wide Range ◽  
High Resolution Spectrometer

AbstractUnlike the single grating Czerny–Turner configuration spectrometers, a super-high spectral resolution optical spectrometer with zero coma aberration is first experimentally demonstrated by using a compound integrated diffraction grating module consisting of 44 high dispersion sub-gratings and a two-dimensional backside-illuminated charge-coupled device array photodetector. The demonstrated super-high resolution spectrometer gives 0.005 nm (5 pm) spectral resolution in ultra-violet range and 0.01 nm spectral resolution in the visible range, as well as a uniform efficiency of diffraction in a broad 200 nm to 1000 nm wavelength region. Our new zero-off-axis spectrometer configuration has the unique merit that enables it to be used for a wide range of spectral sensing and measurement applications.

Probabilistic Model of the Reflectivity of Construction Materials of the Agroindustrial Complex

2021 ◽  
Vol 3 (44) ◽  
pp. 111-115
Author(s):  
Tat’yana R. Gallyamova ◽  
Keyword(s):  
Mathematical Model ◽  
Energy Consumption ◽  
Reflection Coefficient ◽  
Probabilistic Method ◽  
Construction Materials ◽  
Research Purpose ◽  
Visible Range ◽  
Industrial Complex ◽  
Large Area ◽  
Wide Range

When developing modern lighting technologies for objects of the agro-industrial complex, the problem arises of assessing the contribution of reflected light to the normalized illumination. The reflective properties of the surfaces of materials are characterized by a reflection coefficient ρ, which reaches a value of 0.7. This allows us to consider the reflective surfaces as an additional light source and the possibility of reducing energy consumption costs. (Research purpose) The research purpose is in developing a mathematical model that allows us to estimate the spectral reflection coefficient ρ(λ) of materials of construction technologies of the agro-industrial complex in the ultraviolet and visible spectral regions. (Materials and methods) That the disadvantage of various models is the lack of an analytical method for calculating the reflection coefficient in a wide range of wavelengths. We used a probabilistic method to overcome this disadvantage. (Results and discussion) The developed mathematical model makes it possible to estimate the reflection coefficient of the rough surface of materials in a wide range of the spectrum. For concrete, the area of agreement between theory and experiment is in the wavelength range from 250 to 1000 nm. The saturation mode predicted by the theory (the independence of the reflection coefficient from the wavelength) at a reflection coefficient of 0.4 is consistent with the experimental values in the visible range of the spectrum for construction materials of the agro-industrial complex, in particular, gray textured concrete, gray facade paint, light wood, gray silicate brick, new plaster without whitewash. (Conclusions) In the case of normal light incidence, the developed mathematical model allows us to theoretically estimate the reflection coefficient of the rough surfaces of construction technologies of the agro-industrial complex. The proposed model can be used in the development and design of a system of technological lighting of large-area premises (for example, when keeping birds on the floor), as well as for developing recommendations for reducing the energy consumption of existing lighting systems.

Processing Liquid Organic Wastes at the NNL Preston Laboratory

2013 ◽  
Author(s):  
Duncan Coppersthwaite ◽  
Howard Greenwood ◽  
Tahera Docrat ◽  
Sarah Allinson ◽  
Ruqayyah Sultan ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Inert Atmosphere ◽  
Organic Wastes ◽  
Nuclear Industry ◽  
Processing Plant ◽  
Ceramic Processing ◽  
Solvent Treatment ◽  
Physical Form ◽  
Wide Range ◽  
Processing Plants

Organic compounds of various kinds have been used in the nuclear industry for numerous duties in uranium chemical, metal and ceramic processing plants. In the course of the various operations undertaken, these organic compounds have become contaminated with uranic material, either accidentally or as an inevitable part of the process. Typically, the chemical/physical form and/or concentration of the uranic content of the organics has prevented disposal. In order to address the issue of contaminated liquid organic wastes, the National Nuclear Laboratory (NNL) has developed a suite of treatments designed to recover uranium and to render the waste suitable for disposal. The developed processes are operated at industrial scale via the NNL Preston Laboratory Residue Processing Plant. The Oil Waste Leaching (OWL) Process is a fully industrialised process used for the treatment of contaminated oils with approximately 200 tonnes of uranium contaminated oil being treated to date. The process was originally developed for the treatment of contaminated tributyl phosphate and odourless kerosene which had been adsorbed onto sawdust. However, over the years, the OWL process has been refined for a range of oils including “water emulsifiable” cutting oils, lubricating oils, hydraulic oils/fluids and “Fomblin” (fully fluorinated) oils. Chemically, the OWL process has proved capable of treating solvents as well as oils but the highly volatile/flammable nature of many solvents has required additional precautions compared with those required for oil treatment. These additional precautions led to the development of the Solvent Treatment Advanced Rig (STAR), an installation operated under an inert atmosphere. STAR is a small “module” (100 dm3 volume) which allows the treatment of both water miscible and immiscible solvents. This paper discusses the challenges associated with the treatment of liquid organic wastes and the process developments which have allowed a wide range of materials to be successfully treated.

Dependence of visible spectrum [epsilon (lambda)] of fully oxygenated hemoglobin on concentration of hemoglobin

1982 ◽  
Vol 52 (1) ◽  
pp. 124-130 ◽  
Author(s):  
O. Burkhard ◽  
W. K. Barnikol
Keyword(s):  
Extinction Coefficient ◽  
Visible Spectrum ◽  
The Self ◽  
Visible Range ◽  
Animal Blood ◽  
Wide Range ◽  
Beer's Law ◽  
Beer’S Law ◽  
Self Association ◽  
Soret Region

Lambert-Beer's law assumes that the extinction coefficient of a dye is not influenced by its concentration. Some experiments of Barnikol (Proc. Int. Congr. Physiol. Sci. 27th Paris 1977; Respiration 36: 86–95, 1978) led to the presumption that especially at highly concentrated hemoglobin (Hb) solutions Lambert-Beer's law does not hold. To further elucidate this problem we have measured the extinction coefficient of completely oxygenated hemoglobin (epsilon HbO2) over a wide range of Hb concentrations (CHbO2). Our results prove clearly that epsilon HbO2 in visible range as well as in the Soret region depends on CHbO2. In our opinion the invalidity of Lambert-Beer's law is caused by the self-association of the Hb molecules. This concept is a powerful tool to explain the high n values (n greater than 4) which were obtained by some authors in animal blood (bird, frog, trout, earthworm). Furthermore the influence of the self-association on the physicochemical properties of concentrated solutions of human hemoglobin is discussed.

A Preliminary Study on Cell Wall Architecture of Titanium Foams

2009 ◽  
Vol 1188 ◽  
Author(s):  
Nihan Tuncer ◽  
Luc Salvo ◽  
Eric Maire ◽  
Gürsoy Arslan
Keyword(s):  
Weight Ratio ◽  
Cost Savings ◽  
High Strength ◽  
Processing Parameters ◽  
Inert Atmosphere ◽  
Theoretical Density ◽  
Space Holder ◽  
Wide Range ◽  
Powder Characteristics ◽  
Foamed Metals

AbstractBio-inspired architectures, especially metallic foams, have been receiving an increasing interest for the last 10 years due to their unusual mechanical properties. Among commonly dealt foamed metals, like aluminum and steel, titanium possesses a distinctive place because of its high strength-to-weight ratio, excellent corrosion resistance and biocompatibility. In this study, Ti foams were produced by a very simple and common method, sintering under inert atmosphere with fugitive space holder. Removal of the space holder was conducted by dissolution in hot deionized water which makes it possible to minimize contamination of Ti. Sintering of remaining Ti skeleton at 1300 °C offered a wide range of properties and cost savings. The effects of the processing parameters such as sintering temperature and powder characteristics on the 3D foam architecture were investigated by using X-ray microtomography (μ-CT). Use of bimodal Ti powders caused a decrease in final theoretical density when compared to the ones prepared with the same amount of space holder but with monomodal Ti powders. It was also observed that the use of bimodal Ti powders decreased compressive strength, by introducing pores into the cell walls, when compared to the ones having the same theoretical density.

Effect of Injection Rate Shaping Over Diesel Spray Development in Non Reacting Evaporative Conditions

2012 ◽  
Author(s):  
Raul Payri ◽  
Jaime Gimeno ◽  
Michele Bardi ◽  
Alejandro Plazas
Keyword(s):  
Fuel Injection ◽  
Cone Angle ◽  
Injection Rate ◽  
Effective Diameter ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Test Conditions ◽  
Needle Position ◽  
Rate Shaping ◽  
Wide Range

A prototype Diesel common rail direct-acting piezoelectric injector has been used to study the influence of fuel injection rate shaping on spray behavior (liquid phase penetration) under evaporative and non-reacting conditions. This state of the art injector allows a fully flexible control of the nozzle needle, enabling various fuel injection rates typologies under a wide range of test conditions. The tests have been performed employing a novel continuous flow test chamber that allows an accurate control on a wide range of thermodynamic test conditions (up to 1000 K and 15 MPa). The temporal evolution of the spray has been studied recording movies of the injection event with a fast camera (25 kfps) by means of the Mie scattering visualization technique. The analysis of the results showed a strong influence of needle position on the behavior of the liquid length. The needle position controls the effective pressure upstream of the nozzle holes. Higher needle lift is equivalent to higher effective pressures. According to the free-jet theory, the stabilized liquid-length depends mainly on effective diameter, spray cone-angle and fuel/air properties and does not depend on injection velocity. Therefore, higher injection pressures gives slightly lower liquid length due to small change in the spray cone-angle. However, partial needle lifts has an opposite effect: lower effective pressure upstream of the nozzle holes shows a dramatic increase on the spray cone-angle, reducing the liquid length. This behavior could be explained mainly due to the fact that the flow direction upstream of the nozzle holes is affecting the area coefficient, or in other words, the effective diameter of the holes.

Thin Films of Antimony-Tin Oxide as Counter-Electrodes for Proton Working Electrochromic Devices

2001 ◽  
Vol 692 ◽  
Author(s):  
N. Naghavi ◽  
C. Marcel ◽  
L. Dupont ◽  
A. Rougier ◽  
J-M. Tarascon
Keyword(s):  
Thin Films ◽  
Tin Oxide ◽  
Optical Transmittance ◽  
Ex Situ ◽  
Visible Range ◽  
Electrochromic Devices ◽  
Counter Electrodes ◽  
Transmission Electron ◽  
Wide Range ◽  
Antimony Tin Oxide

AbstractWe report here on thin films proton-working electrochromic devices based on the wellknown tungsten oxide as the coloring electrode, and Antimony Tin Oxide (ATO) as the ionstorage counter-electrode. We show that films deposited by Pulsed Laser Deposition (PLD) technique have an apparent Sb solubility up to 70 at %, and exhibit unusual electrochromic properties. Through potentiostatic tests we'll demonstrate that depending on the composition which influences film morphology, the Sn-Sb-O films could either present a faradic or a capacitive-like behavior, associated to a color or a neutral switching over a wide range of potentials, respectively. The structural properties of ATO films are characterized by X-ray diffraction and transmission electron microscopy (TEM). Electrochromic behavior is studied by means of cyclic voltamperometry coupled with ex situ optical transmittance measurements in the visible range. The maximum proton-storage capacity is observed for ATO films containing 40–50 at % Sb, while being quasi-neutral when switching over a wide range of potentials. These compositions are finally retained for the assembly of our WO3/proton-electrolyte/ATO devices, whose performances are reported.

Photoelectric current spectra of copper-doped cadmium selenide crystals over a wide range of concentrations

1975 ◽  
Vol 23 (5) ◽  
pp. 1487-1491
Author(s):  
V. E. Mashchenko ◽  
A. G. Gusachenko ◽  
V. M. Vantsan ◽  
B. M. Bulgakov
Keyword(s):  
Cadmium Selenide ◽  
Photoelectric Current ◽  
Wide Range

scholarly journals Epoxyorganosilane Finishing Compositions for Fibrous Fillers of Thermosetting and Thermoplastic Binders

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 59
Author(s):  
Alexey V. Shapagin ◽  
Natalia A. Gladkikh ◽  
Arkadiy A. Poteryaev ◽  
Valentina Yu. Stepanenko ◽  
Uliana V. Nikulova ◽  
...  
Keyword(s):  
Free Energy ◽  
Composite Materials ◽  
Surface Free Energy ◽  
Materials Science ◽  
Sessile Drop ◽  
Inert Atmosphere ◽  
Energy Characteristics ◽  
Urgent Task ◽  
Wide Range ◽  
Epoxy Systems

The development of universal finishing compositions for fibers of various natures is an urgent task for polymer composite materials science. The developed finishes can be used for the fiber reinforcement of polymer matrices with a wide range of surface free energy characteristics. Epoxy systems modified with diaminesilane in a wide concentration range were examined by optical interferometry, FTIR spectroscopy, DSC and the sessile drop technique. It was shown that the partial curing of epoxy resin by diaminesilane at room temperature under an inert atmosphere, followed by contact with air, leads to a significant increase of the surface free energy of the system. Varying the concentration of diaminesilane allows us to effectively regulate the surface free energy of the composition. This makes it possible to use fibers finished with epoxyaminosilane compositions in composite materials based on a various thermosetting and thermoplastic binders with a surface tension of up to 75 mJ/m2.

scholarly journals In-situ microphysical characterization of low-level clouds in the Finnish sub-Arctic, extensive dataset

2021 ◽  
Author(s):  
Konstantinos Matthaios Doulgeris ◽  
Heikki Lihavainen ◽  
Anti-Pekka Hyvärinen ◽  
Veli-Matti Kerminen ◽  
David Brus
Keyword(s):  
Open Data ◽  
Arctic Region ◽  
Liquid Water Content ◽  
Dew Point ◽  
Data Repository ◽  
Effective Diameter ◽  
Data Sets ◽  
Low Level ◽  
Wide Range

Abstract. Continuous, semi-long-term, ground based in-situ cloud measurements were conducted during eight Pallas Cloud Experiments (PaCE) held in autumns between 2004 and 2019. Campaigns were carried out in the Finnish sub-Arctic region at the Sammaltunturi station (67°58′24′′ N, 24°06′58′′ E; 560 m MSL), the part of Pallas Atmosphere – Ecosystem Supersite and Global Atmosphere Watch (GAW) program. Two cloud spectrometer ground setups and a weather station were installed on the roof of the station to measure in-situ cloud properties and several meteorological variables. Thus, the obtained data sets include the size distribution of cloud droplets as a measured cloud parameter along with the temperature, dew point temperature, humidity, pressure, wind speed and direction, (global solar) sun radiation and visibility at the station. Additionally, the number concentration, effective diameter, median volume diameter and liquid water content from each instrument were derived. The presented data sets provide a great insight into microphysics of low-level clouds in sub-Arctic conditions over a wide range of temperatures (includes cloud cases with temperature from -25.8 to 8.8 °C). The data are available from the FMI open data repository for each campaign and each cloud spectrometer ground setup individually: https://doi.org/10.23728/FMI-B2SHARE.988739D21B824C709084E88ED6C6D54B (Doulgeris et al., 2021).

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