Features of the Band-Edge Injection Electroluminescence in 4H-SiC pn Structures

2015 ◽  
Vol 821-823 ◽  
pp. 289-292
Author(s):  
Anatoly M. Strel'chuk ◽  
Yury S. Kuz’michev ◽  
Konstantin F. Shtel’makh
Keyword(s):  
Activation Energy ◽  
Irradiation Temperature ◽  
Band Edge ◽  
Fundamental Feature ◽  
Wide Range ◽  
Current Densities ◽  
Increasing Temperature ◽  
First Time ◽  
Injection Electroluminescence ◽  
Nonequilibrium Carriers

Band-edge (hνmax=3.17-3.18 eV at T=293 K) injection electroluminescence (IEL) characteristics of 4H-SiC pn structures as a function of doping, electron irradiation, temperature, and current are presented. The intensity of the UV band increases with temperature in the range 290-800 K (with an activation energy Ea of about 90 meV), which is observed for the first time in a wide range of current densities from 9 A/cm2 up to 2∙104 A/cm2. This effect is a fundamental feature of the band-edge IEL in SiC pn structures. The dependence of the intensity L on the current is of the power-law type, L~Jm; at high currents m≈1 at T=650-800 K. This result is probably the first direct observation of the diffusion current in SiC pn structures. The rise in the intensity of the band-edge IEL with increasing temperature and its decrease upon irradiation are probably due to the corresponding change in the lifetime of nonequilibrium carriers.

Temperature Dependence of the Band-Edge Injection Electroluminescence of 3C-SiC pn Structure

2007 ◽  
Vol 556-557 ◽  
pp. 427-430 ◽  
Author(s):  
Anatoly M. Strel'chuk ◽  
Alexander A. Lebedev ◽  
N.S. Savkina ◽  
Alexey N. Kuznetsov
Keyword(s):  
Activation Energy ◽  
Emission Band ◽  
Room Temperature ◽  
Free Exciton ◽  
Charge Carriers ◽  
Full Width ◽  
Half Maximum ◽  
Exciton Annihilation ◽  
Increasing Temperature ◽  
Injection Electroluminescence

We present the injection electroluminescence spectra in the temperature range 290-760 K of 3C-SiC pn structure, which was fabricated by sublimation epitaxy in vacuum on 6H-SiC substrate. The dominant emission band of injection electroluminescence (IEL) spectrum was observed in the green region; at room temperature the IEL intensity outside the region of hν ≈ 2.0- 2.5 eV was less than 3% of that of the green peak. The peak parameters at room temperature are: hνmax ≈ 2.32 eV, full width at half maximum w ≈ 100 meV. The green peak shifted in the longwave direction with increasing temperature; the hνmax (T) dependence was linear with the slope of - 1.3x10-4 eV/K. Both the IEL intensity of the green peak at hνmax and band width w increased upon heating. The w(T) dependence was linear with the slope of 4.6x10-4 eV/K; intensity increased with the activation energy of 70 meV. The green IEL band can be considered to be due to the free exciton annihilation or to the band-band recombination and edge IEL increasing with rising temperature can be explained by the nonequilibrium charge carriers lifetime increasing.

scholarly journals Utilization of Bitter orange seeds as a novel source for recovery of pectin: Compositional and rheological characterization

2021 ◽  
Author(s):  
Mohammad Nejatian ◽  
Diako Khodaei ◽  
Hassan Ahmadi Gavlighi ◽  
Azizollaah Zargaraan
Keyword(s):  
Flow Behavior ◽  
Rheological Characterization ◽  
Flow Behavior Index ◽  
Bitter Orange ◽  
Rheological Measurements ◽  
Wide Range ◽  
Neutral Sugars ◽  
Strain Sweep ◽  
Increasing Temperature ◽  
First Time

Abstract The seeds from bitter orange, a by-product from the juice making step, hold the potential to facilitate novel, easy yet high quality pectin extraction. To test this hypothesis, the pectin from orange seeds (OSP) were extracted by distilled water and its compositional parameters and rheological behavior then evaluated. Results showed that galacturonic acid was the major component of OSP (~ 425 mg/g) confirming the purity of extracted pectin, followed by glucose and some minor neutral sugars. Mw, Rn and, Rz for the OSP were 4511.8 (kDa), 61 (nm), and 61.1 (nm), respectively. Rheological measurements showed shear-thinning behavior for OSP that by increasing temperature from 5 to 45 oC, the viscosity of the gum decreased. Power law fitted as the best rheological model describing the flow behavior of OSP. Strain sweep dynamic rheological measurements confirmed an entangled network structure for OSP and the addition of NaCl to the gum dispersion, decreased the consistency coefficient from 35.6 to 23.18 Pa.sn, while the flow behavior index remained unchanged. These results demonstrate for the first time that the OSP can be used as a new source of pectin, with likely a wide range of applications in food industry.

Temperature Dependence of the Band-Edge Injection Electroluminescence of 4H-SiC pn Structure

2013 ◽  
Vol 740-742 ◽  
pp. 569-572 ◽  
Author(s):  
Anatoly M. Strel'chuk ◽  
Evgenia V. Kalinina ◽  
Alexander A. Lebedev
Keyword(s):  
Room Temperature ◽  
Charge Carriers ◽  
Band Edge ◽  
Near Band Edge ◽  
Full Width ◽  
Wave Direction ◽  
Green Band ◽  
Long Wave ◽  
Increasing Temperature ◽  
Injection Electroluminescence

We present the injection electroluminescence spectra in the temperature range 290-800 K of 4H-SiC pn structure, which was formed by implantation of Al+ ions in low-doped n-type conductivity 4H-SiC epitaxial layer. The dominant emission band of injection electroluminescence (IEL) spectrum at room temperature was observed in the blue-green region; as the temperature is raised, the blue-green band is quenched, while UV band (near band-edge) IEL become dominant. The peak parameters of UV band at room temperature are: hmax  3.17 eV, full width at half maximum w  90 meV. The UV peak shifted in the long-wave direction with increasing temperature; the hmax (T) dependence was linear with the slope of -2.3∙10-4 eV/K. Both the IEL intensity of the UV peak at hmax and band width w increased upon heating. The w(T) dependence was linear with the slope of 2.9∙10-4 eV/K; intensity increased with the activation energy of 100-150 meV. The UV IEL band can be considered more probable to the band-band recombination and edge IEL increasing with rising temperature can be explained by the nonequilibrium charge carriers lifetime increasing.

scholarly journals Utilization of Bitter orange seeds as a novel source for recovery of pectin: Compositional and rheological characterization

2021 ◽  
Author(s):  
Mohammad Nejatian ◽  
Diako Khodaei ◽  
Hassan Ahmadi Gavlighi ◽  
Azizollaah Zargaraan
Keyword(s):  
Flow Behavior ◽  
Rheological Characterization ◽  
Flow Behavior Index ◽  
Bitter Orange ◽  
Rheological Measurements ◽  
Wide Range ◽  
Neutral Sugars ◽  
Strain Sweep ◽  
Increasing Temperature ◽  
First Time

Abstract The seeds from bitter orange, a by-product from the juice making step, hold the potential to facilitate novel, easy yet high quality pectin extraction. To test this hypothesis, the pectin from orange seeds (OSP) were extracted by distilled water and its compositional parameters and rheological behavior then evaluated. Results showed that galacturonic acid was the major component of OSP (~ 425 mg/g) confirming the purity of extracted pectin, followed by glucose and some minor neutral sugars. Mw, Rn and, Rz for the OSP were 4511.8 (kDa), 61 (nm), and 61.1 (nm), respectively. Rheological measurements showed shear-thinning behavior for OSP that by increasing temperature from 5 to 45 oC, the viscosity of the gum decreased. Power law fitted as the best rheological model describing the flow behavior of OSP. Strain sweep dynamic rheological measurements confirmed an entangled network structure for OSP and the addition of NaCl to the gum dispersion, decreased the consistency coefficient from 35.6 to 23.18 Pa.sn, while the flow behavior index remained unchanged. These results demonstrate for the first time that the OSP can be used as a new source of pectin, with likely a wide range of applications in food industry.

scholarly journals Utilization of Bitter orange seeds as a novel source for recovery of pectin: Compositional and rheological characterization

2022 ◽  
Author(s):  
Diako Khodaei ◽  
Mohammad Nejatian ◽  
Hassan Ahmadi Gavlighi ◽  
Farhad Garavand ◽  
Ilaria Cacciotti
Keyword(s):  
Flow Behavior ◽  
Rheological Characterization ◽  
Flow Behavior Index ◽  
Bitter Orange ◽  
Rheological Measurements ◽  
Wide Range ◽  
Neutral Sugars ◽  
Strain Sweep ◽  
Increasing Temperature ◽  
First Time

Abstract The seeds from bitter orange, a by-product from the juice making step, hold the potential to facilitate novel, easy yet high quality pectin extraction. To test this hypothesis, the pectin from orange seeds (OSP) were extracted by distilled water and its compositional parameters and rheological behavior then evaluated. Results showed that galacturonic acid was the major component of OSP (~ 425 mg/g) confirming the purity of extracted pectin, followed by glucose and some minor neutral sugars. Mw, Rn and, Rz for the OSP were 4511.8 (kDa), 61 (nm), and 61.1 (nm), respectively. Rheological measurements showed shear-thinning behavior for OSP that by increasing temperature from 5 to 45 oC, the viscosity of the gum decreased. Power law fitted as the best rheological model describing the flow behavior of OSP. Strain sweep dynamic rheological measurements confirmed an entangled network structure for OSP and the addition of NaCl to the gum dispersion, decreased the consistency coefficient from 35.6 to 23.18 Pa.sn, while the flow behavior index remained unchanged. These results demonstrate for the first time that the OSP can be used as a new source of pectin, with likely a wide range of applications in food industry.

Theoretical study of the prestressing strand's stress by computer modeling methods

2020 ◽  
Vol 76 (11) ◽  
pp. 1139-1148
Author(s):  
A. G. Korchunov ◽  
E. M. Medvedeva ◽  
E. M. Golubchik
Keyword(s):  
Residual Stresses ◽  
High Strength ◽  
Pearlitic Steel ◽  
Internal Stresses ◽  
Steel Microstructure ◽  
Compressive Stresses ◽  
Wide Range ◽  
Prestressing Strands ◽  
Increasing Temperature ◽  
Wire Strand

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.

Safety assessment of biological raw materials in the system of medicines quality assurance

2020 ◽  
pp. 63-72
Author(s):  
Yu. Olefir ◽  
E. Sakanyan ◽  
I. Osipova ◽  
V. Dobrynin ◽  
M. Smirnova ◽  
...  
Keyword(s):  
Raw Materials ◽  
State Level ◽  
The State ◽  
Spongiform Encephalopathy ◽  
Safety Standards ◽  
Wide Range ◽  
The Russian Federation ◽  
Key Aspects ◽  
First Time ◽  
Medicines Quality

The entry of a wide range of biotechnological products into the pharmaceutical market calls for rein-forcement of the quality, efficacy and safety standards at the state level. The following general monographs have been elaborated for the first time to be included into the State Pharmacopoeia of the Russian Federation, XIV edition: "Viral safety" and "Reduction of the risk of transmitting animal spongiform encephalopathy via medicinal products". These general monographs were elaborated taking into account the requirements of foreign pharmacopoeias and the WHO recommendations. The present paper summarises the key aspects of the monographs.

Innovation in Byzantine Medicine

2020 ◽  
Author(s):  
Petros Bouras-Vallianatos
Keyword(s):  
Human Physiology ◽  
Medical Literature ◽  
Cultural Exchange ◽  
Significant Degree ◽  
Medieval Medicine ◽  
Medieval Latin ◽  
Main Thesis ◽  
Wide Range ◽  
Comprehensive Examination ◽  
First Time

Byzantine medicine is still a little-known and misrepresented field not only in the wider arena of debates on medieval medicine but also among Byzantinists. Byzantine medical literature is often viewed as ‘stagnant’ and mainly preserving ancient ideas; and our knowledge of it continues to be based to a great extent on the comments of earlier authorities, which are often repeated uncritically. This book presents the first comprehensive examination of the medical corpus of, arguably, the most important late Byzantine physician John Zacharias Aktouarios (c.1275–c.1330). The main thesis is that John’s medical works show an astonishing degree of openness to knowledge from outside Byzantium combined with a significant degree of originality, in particular, in the fields of uroscopy, pharmacology, and human physiology. The analysis of John’s edited (On Urines and On Psychic Pneuma) and unedited (Medical Epitome) works is supported for the first time by the consultation of a large number of manuscripts. The study is also informed by evidence from a wide range of medical sources, including previously unpublished ones, and texts from other genres, such as epistolography and merchants’ accounts. The contextualization of John’s works sheds new light on the development of Byzantine medical thought and practice, and enhances our understanding of the late Byzantine social and intellectual landscape. Finally, John’s medical observations are also examined in the light of examples from the medieval Latin and Islamic worlds, placing his medical theories in the wider Mediterranean milieu and highlighting the cultural exchange between Byzantium and its neighbours.

Rebels, Believers, Survivors

2020 ◽  
Author(s):  
Noel Malcolm
Keyword(s):  
Catholic Church ◽  
Religious Conversion ◽  
Late Nineteenth Century ◽  
Napoleonic Wars ◽  
Conversion To Islam ◽  
Wide Range ◽  
History Of ◽  
External Powers ◽  
First Time ◽  
Modern Myth

This book of essays covers a wide range of topics in the history of Albania and Kosovo. Many of the essays illuminate connections between the Albanian lands and external powers and interests, whether political, military, diplomatic or religious. Such topics include the Habsburg invasion of Kosovo in 1689, the manoeuvrings of Britain and France towards the Albanian lands during the Napoleonic Wars, the British interest in those lands in the late nineteenth century, and the Balkan War of 1912. On the religious side, essays examine ‘crypto-Christianity’ in Kosovo during the Ottoman period, the stories of conversion to Islam revealed by Inquisition records, the first theological treatise written in Albanian (1685), and the work of the ‘Apostolic Delegate’ who reformed the Catholic Church in early twentieth-century Albania. Some essays bring to life ordinary individuals hitherto unknown to history: women hauled before the Inquisition, for example, or the author of the first Albanian autobiography. The longest essay, on Ali Pasha, tells for the first time the full story of the role he played in the international politics of the Napoleonic Wars. Some of these studies have been printed before (several in hard-to-find publications, and one only in Albanian), but the greater part of this book appears here for the first time. This is not only a contribution to Albanian and Balkan history it also engages with many broader issues, including religious conversion, methods of enslavement within the Ottoman Empire, and the nature of modern myth-making about national identity.

Recycling and Reuse in the Roman Economy

2020 ◽  
Keyword(s):  
Building Materials ◽  
Computational Modelling ◽  
Late Antique ◽  
Roman Economy ◽  
Wide Range ◽  
The Status ◽  
Recent Developments ◽  
Methodological Approaches ◽  
First Time ◽  
Site Types

The recycling and reuse of materials and objects were extensive in the past, but have rarely been embedded into models of the economy; even more rarely has any attempt been made to assess the scale of these practices. Recent developments, including the use of large datasets, computational modelling, and high-resolution analytical chemistry, are increasingly offering the means to reconstruct recycling and reuse, and even to approach the thorny matter of quantification. Growing scholarly interest in the topic has also led to an increasing recognition of these practices from those employing more traditional methodological approaches, which are sometimes coupled with innovative archaeological theory. Thanks to these efforts, it has been possible for the first time in this volume to draw together archaeological case studies on the recycling and reuse of a wide range of materials, from papyri and textiles, to amphorae, metals and glass, building materials and statuary. Recycling and reuse occur at a range of site types, and often in contexts which cross-cut material categories, or move from one object category to another. The volume focuses principally on the Roman Imperial and late antique world, over a broad geographical span ranging from Britain to North Africa and the East Mediterranean. Last, but not least, the volume is unique in focusing upon these activities as a part of the status quo, and not just as a response to crisis.

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