Instrumental Distortions of Raman Lines

1982 ◽  
Vol 36 (4) ◽  
pp. 424-427 ◽  
Author(s):  
A. K. Arora ◽  
V. Umadevi
Keyword(s):  
Low Temperatures ◽  
Full Width ◽  
Line Shapes ◽  
Peak Intensity ◽  
Empirical Relations ◽  
Extended Range ◽  
Main Component ◽  
Lorentzian Spectrum ◽  
True Peak ◽  
Better Than

The effect of spectrometer resolution on the peak intensity and the full width at half maximum (FWHM) of a Lorentzian spectrum is obtained by evaluating the convoluted line shapes. Spectrometer resolution functions (SRF) having Gaussian and triangular profiles are considered separately. Empirical relations to estimate the true peak intensity and the FWHM from the observed parameters are suggested. These relations are valid over an extended range of parameters with an accuracy better than that of other methods suggested earlier. As an application, the true FWHM's and peak intensities of the main component of the Raman active Ag mode of sulphate ion in potash alum at low temperatures are evaluated.

The Experimental Study on the Inhibition Effect of Fusarium oxyspomm with Bio-Slurry Based on Material Properties

2013 ◽  
Vol 675 ◽  
pp. 317-321
Author(s):  
Meng Ying Fang ◽  
Li Chun Liu ◽  
Fang Yin ◽  
Wu Di Zhang ◽  
Shi Qing Liu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Material Properties ◽  
Water Soluble ◽  
Inhibition Mechanism ◽  
Main Subject ◽  
Soluble Substance ◽  
Inhibition Effect ◽  
Water Soluble Substance ◽  
Main Component ◽  
Better Than

Using petroleum ether to extract the fermentative fluid (bio-slurry), then to get the inhibition mechanism of it, and infer which is the main component in inhibition mechanism of biogas. The conclusion found by the experiment is that fat soluble substance is better than water soluble substance in inhibition mechanism, and fat soluble substance is close to 75% biogas fermentation fluid, while water soluble substance is worst. That is to say, the main subject in inhibition mechanism is hided in the fat soluble substance.

Improvement of Strength of Mg-12Gd-3Y-0.5Zr Alloys Processed by Combination of ECAP and Extrusion

2011 ◽  
Vol 682 ◽  
pp. 211-216
Author(s):  
Rong Zhu ◽  
Jin Qiang Liu ◽  
Jing Tao Wang ◽  
Ping Huang ◽  
Yan Jun Wu ◽  
...  
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Grain Boundary ◽  
Low Temperatures ◽  
Basal Slip ◽  
Extrusion Direction ◽  
Strengthening Mechanisms ◽  
Step Process ◽  
Angular Pressing ◽  
Peak Intensity

Equal channel angular pressing (ECAP) has been used to refine the grain size of Mg-12Gd-3Y-0.5Zr billet at about 400°C because it lacks sufficient ductility at low temperatures. However, <0001> peak intensity is oriented about 50º from the extrusion direction, which facilitates the basal slip, and decreases the yield strength. We have employed conventional extrusion at 300°C following ECAP to modify the texture in hard orientation. This two-step process makes use of two strengthening mechanisms a) grain boundary strengthening due to small grain size, and (b) texture strengthening due to grains in hard orientation. The samples processed by the two-step show the yield and ultimate strength to 283 and 308 MPa, respectively. Moreover, the activation of <c+a> slip and fine grains resulted from the ECAP helped to maintain a good ductility even after significant straining from conventional extrusion.

scholarly journals Dehumidified Air-Assisted Spray-Drying of Cloudy Beetroot Juice at Low Temperature

2021 ◽  
Vol 11 (14) ◽  
pp. 6578
Author(s):  
Aleksandra Jedlińska ◽  
Alicja Barańska ◽  
Dorota Witrowa-Rajchert ◽  
Ewa Ostrowska-Ligęza ◽  
Katarzyna Samborska
Keyword(s):  
Particle Size ◽  
Physicochemical Properties ◽  
Spray Drying ◽  
Low Temperatures ◽  
Beetroot Juice ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Tapped Density ◽  
Lower Loss ◽  
Better Than

This paper discusses the physicochemical properties of powders obtained by spray drying of cloudy beetroot juice, using dehumidified air in variants with or without carriers. The inlet air temperature was 130 °C or 90 °C, and the addition of the carriers was at a ratio of juice to carrier solids of 3:2. In the obtained powders, the following physicochemical properties were determined: water content and water activity, apparent density, loose and tapped density, porosity, flowability, particle size and morphology, and the content and retention of betalains. It was possible to dry cloudy beetroot juice without the use of carriers at low temperatures (90 or 130 °C). The 100% beetroot powders were characterized by satisfactory physicochemical properties, often better than those with carriers (including lower hygroscopicity and higher color saturation and yield). A lower loss of betalains was found for the powders with the addition of carriers. The best process yields were obtained for the powder without carriers at 130 °C and 90 °C.

The Effect of Modified Crucible Design and Seed Attachment on SiC Crystal Grown by PVT

2013 ◽  
Vol 740-742 ◽  
pp. 77-80
Author(s):  
Jung Young Jung ◽  
Sang Il Lee ◽  
Mi Seon Park ◽  
Doe Hyung Lee ◽  
Hee Tae Lee ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Temperature Gradient ◽  
Single Crystals ◽  
Crystal Quality ◽  
Full Width ◽  
Half Maximum ◽  
Radial Temperature Gradient ◽  
Radial Temperature ◽  
Better Than

The present research was focused to investigate the effect of internal crucible design that influenced the 4H-SiC crystal growth onto a 6H-SiC seed by PVT method. The crucible design was modified to produce a uniform radial temperature gradient in the growth cell. The seed attachment was also modified with a use of polycrystalline SiC plate. The crystal quality of 4H-SiC single crystals grown in modified crucible and grown with modified seed attachment was revealed to be better than that of crystal grown in conventional crucible. The full width at half maximum (FWHM) values of grown SiC crystals in the conventional crucible, the modified seed attachment and the modified crucible were 285 arcsec, 134 arcsec and 128 arcsec, respectively. The micropipe density (MPD) of grown SiC crystals in the conventional crucible, the modified seed attachment and the modified crucible were 101ea/cm^2, 81ea/cm^2 and 42ea/cm^2, respectively.

scholarly journals PPDIST, global 0.1° daily and 3-hourly precipitation probability distribution climatologies for 1979–2018

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Hylke E. Beck ◽  
Seth Westra ◽  
Jackson Tan ◽  
Florian Pappenberger ◽  
George J. Huffman ◽  
...  
Keyword(s):  
Neural Networks ◽  
Probability Distribution ◽  
State Of The Art ◽  
Intertropical Convergence Zone ◽  
Coefficient Of Determination ◽  
Current State ◽  
Peak Intensity ◽  
Global Land ◽  
The Neural Networks ◽  
Better Than

Abstract We introduce the Precipitation Probability DISTribution (PPDIST) dataset, a collection of global high-resolution (0.1°) observation-based climatologies (1979–2018) of the occurrence and peak intensity of precipitation (P) at daily and 3-hourly time-scales. The climatologies were produced using neural networks trained with daily P observations from 93,138 gauges and hourly P observations (resampled to 3-hourly) from 11,881 gauges worldwide. Mean validation coefficient of determination (R2) values ranged from 0.76 to 0.80 for the daily P occurrence indices, and from 0.44 to 0.84 for the daily peak P intensity indices. The neural networks performed significantly better than current state-of-the-art reanalysis (ERA5) and satellite (IMERG) products for all P indices. Using a 0.1 mm 3 h−1 threshold, P was estimated to occur 12.2%, 7.4%, and 14.3% of the time, on average, over the global, land, and ocean domains, respectively. The highest P intensities were found over parts of Central America, India, and Southeast Asia, along the western equatorial coast of Africa, and in the intertropical convergence zone. The PPDIST dataset is available via www.gloh2o.org/ppdist.

scholarly journals On a formula for the elastic force of vapour at different temperatures

1851 ◽  
Vol 5 ◽  
pp. 738-740
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Elastic Force ◽  
French Academy ◽  
Different Temperatures ◽  
Series Of Experiments ◽  
Better Than

The author adopts as the basis of his formula the first series of experiments at high temperatures made by the French Academy, and those of Magnus at low temperatures. For the Academy’s experiments, he adopts the indications of the smaller thermometer in the steam in preference to those of the larger thermometer in the water. Of Dr. Young’s sort of formulae, he notices that of the Aca­demy and several others with exponents varying from 5 to 7. From the elasticity at freezing, as given by Magnus, compared with four of the Academy’s experiments, he shows that for the range of observation the number 6 is preferable to 5 as an exponent; but, as he states, no formula of this sort with a constant index can be found to agree with the observations throughout. The formula of Magnus he finds to agree with these observations better than any of the others; but being adapted to the air-thermo­meter, and therefore not convenient for ordinary use, he gives his own formula adapted to the mercurial thermometer, t = 500 + 225 log A / 5 - log A, t being the temp. Cent., and A the elasticity in atmospheres of 0 m .76 at zero, or 30 inches at 58° Fahr.; the temperature being given, the formula becomes log A = 5 - 1625 / 225 + t .

TEM Study of the Morphology Of GaN/SiC (0001) Grown at Various Temperatures by MBE

1999 ◽  
Vol 595 ◽  
Author(s):  
W.L. Sarney ◽  
L. Salamanca-Riba ◽  
V. Ramachandran ◽  
R.M Feenstra ◽  
D.W. Greve
Keyword(s):  
Low Temperatures ◽  
Stacking Faults ◽  
Full Width ◽  
X Ray Diffraction ◽  
High Quality ◽  
Double Crystal ◽  
Tem Analysis ◽  
Rocking Curve ◽  
X Ray ◽  
Substrate Temperatures

AbstractGaN films grown on SiC (0001) by MBE at various substrate temperatures (600° - 750° C) were characterized by RHEED, STM, x-ray diffraction, AFM and TEM. This work focuses on the TEM analysis of the films' features, such as stacking faults and dislocations, which are related to the substrate temperature. There are several basal plane stacking faults in the form of cubic inclusions for samples grown at low temperatures compared to those grown at high temperatures. The dislocation density is greatest for the film grown at 600°C, and it steadily decreases with increasing growth temperatures. Despite the presence of various defects, x-ray analysis shows that the GaN films are of high quality. The double crystal rocking curve full width at half maximum (FWHM) for the GaN (0002) peak is less than 2 arc-minutes for all of the films we measured and it decreases with increasing growth temperature.

scholarly journals Low-temperature deicing means

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Andrey Kochetkov ◽  
Leonid Yankovskiy ◽  
Sofia Arganuchina ◽  
Igor' Shashkov ◽  
Alеksandr Bobkov
Keyword(s):  
Low Temperature ◽  
Calcium Chloride ◽  
Low Temperatures ◽  
Raw Materials ◽  
Volume Ratio ◽  
Crystalline Hydrate ◽  
Winter Maintenance ◽  
Effective Application ◽  
Different Types ◽  
Main Component

Low-temperature deicing means belongs to area of winter maintenance of buildings and constructions, can be applied to winter maintenance of highways, various open surfaces subject to influence or different types of manifestations of low temperatures. The objective is reached by that in deicing means containing granules from chlorides, each of granules is executed in the form of pressed mix of chloride calcium and chloride of potassium, at a volume ratio in a granule of chloride potassium and chloride calcium from 2:1 to 4:1, thus between particles of chloride potassium and chloride calcium connecting layer from calcium chloride crystalline hydrate is placed. Thus in a granule volume of chloride potassium makes 45-85%, the volume of waterless chloride calcium of 25-45%, thickness of a connecting layer from calcium chloride crystalline hydrate - 0,01-0,1 mm, and size of a granule makes 2-7 mm. The declared set of signs allows to expand the range of effective application of protigololedny means, to provide its reduction in cost and efficiency of application as a component of deicing material of chloride potassium extracted on a place. The reached efficiency was expressed in expansion of temperature of application in range from 0° to -10°C in comparison with application temperature (as main component) chloride calcium (from -10°C and below). Besides, declared deicing means allows to reduce cost of production of PGM developed from local raw materials by 20-40%.

scholarly journals The Poisoning of V2O5-WO3/TiO2 and V2O5-Ce(SO4)2/TiO2 SCR Catalysts by KCl and The Partial Regeneration by SO2

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 207 ◽  
Author(s):  
Hua Nie ◽  
Wei Li ◽  
Qirong Wu ◽  
Vladislav Rac ◽  
Vesna Rakić ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Alkali Metal ◽  
Low Temperatures ◽  
Catalyst Surface ◽  
Alkali Metal Chlorides ◽  
Metal Chlorides ◽  
Scr Catalyst ◽  
Scr Catalysts ◽  
Vanadium Based Catalysts ◽  
Better Than

Poisoning effects by alkali metal chlorides is one of the major reasons for the deactivation of SCR catalyst in biomass-fired plants. In this study, the influence of KCl on two vanadium-based catalysts with different promoters, V2O5-WO3/TiO2 and V2O5-Ce(SO4)2/TiO2, was investigated. The catalytic activity of the fresh V2O5-WO3/TiO2 was higher than that of V2O5-Ce(SO4)2/TiO2 at low temperatures. V2O5-Ce(SO4)2/TiO2 performed better than V2O5-WO3/TiO2 when KCl was deposited on the catalyst surface. Both poisoned catalysts were efficiently regenerated by SO2 treatment. The characterization results show that the reducibility and acidity of the catalysts were weakened by KCl deposition but regenerated by SO2.

Unusual Properties of the Red and Green Luminescence Bands in Ga-rich GaN

2004 ◽  
Vol 831 ◽  
Author(s):  
M. A. Reshchikov ◽  
H. Morkoç
Keyword(s):  
Low Temperatures ◽  
Molecular Beam ◽  
Deep Level ◽  
Shallow Donor ◽  
Time Resolved ◽  
Temperature Range ◽  
Peak Intensity ◽  
Integrated Intensity ◽  
Valence Bands ◽  
Increasing Temperature

ABSTRACTWe studied photoluminescence (PL) from deep-level defects in GaN grown under Garich conditions at relatively low temperatures (700–800°C) by molecular-beam epitaxy (MBE). The dominant features of PL spectrum are red and green bands peaking respectively at ∼1.8 and ∼2.35 eV. Both PL bands decay exponentially at low temperatures (15 – 100 K) after pulsed excitation. The characteristic lifetime for the red band decreases by almost two orders of magnitude from 110 to 2 μs with increasing temperature from 15 to 100 K, while its integrated intensity after each pulse remains nearly unchanged in the same temperature range due to an increase in the peak intensity in the time-resolved PL curve. The lifetime of the green band remained unchanged in this temperature range. We suggest that these PL bands are caused by transitions between excited and ground states of some deep defects rather than transitions involving a shallow donor, conduction or valence bands.

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