Basic Physics of Plasmas/Discharges: Production of Active Species

1990 ◽  
pp. 1-34 ◽  
Author(s):  
A. Ricard
Keyword(s):  
Active Species ◽  
Basic Physics

Luminescence from individual dislocations in II-VI and III-V semiconductors

1991 ◽  
Vol 49 ◽  
pp. 834-835
Author(s):  
J W Steeds
Keyword(s):  
Group Iv ◽  
Luminescence Properties ◽  
Carrier Recombination ◽  
Transmission Electron ◽  
Wide Range ◽  
Basic Physics ◽  
Semiconducting Compounds ◽  
Diamond Group ◽  
Non Destructive ◽  
Technological Significance

There is a wide range of experimental results related to dislocations in diamond, group IV, II-VI, III-V semiconducting compounds, but few of these come from isolated, well-characterized individual dislocations. We are here concerned with only those results obtained in a transmission electron microscope so that the dislocations responsible were individually imaged. The luminescence properties of the dislocations were studied by cathodoluminescence performed at low temperatures (~30K) achieved by liquid helium cooling. Both spectra and monochromatic cathodoluminescence images have been obtained, in some cases as a function of temperature.There are two aspects of this work. One is mainly of technological significance. By understanding the luminescence properties of dislocations in epitaxial structures, future non-destructive evaluation will be enhanced. The second aim is to arrive at a good detailed understanding of the basic physics associated with carrier recombination near dislocations as revealed by local luminescence properties.

Creating a standard method of controlling digital microscopes: the microscope access protocol (map)

1995 ◽  
Vol 53 ◽  
pp. 16-17
Author(s):  
T. A. Dodson ◽  
E. Völkl ◽  
L. F. Allard ◽  
T. A. Nolan
Keyword(s):  
Data Storage ◽  
Storage Systems ◽  
Digital Systems ◽  
Data Networks ◽  
Digital Microscopy ◽  
Command Language ◽  
Access Protocol ◽  
Analog To Digital ◽  
Basic Physics ◽  
Scanning Electron

The process of moving to a fully digital microscopy laboratory requires changes in instrumentation, computing hardware, computing software, data storage systems, and data networks, as well as in the operating procedures of each facility. Moving from analog to digital systems in the microscopy laboratory is similar to the instrumentation projects being undertaken in many scientific labs. A central problem of any of these projects is to create the best combination of hardware and software to effectively control the parameters of data collection and then to actually acquire data from the instrument. This problem is particularly acute for the microscopist who wishes to "digitize" the operation of a transmission or scanning electron microscope. Although the basic physics of each type of instrument and the type of data (images & spectra) generated by each are very similar, each manufacturer approaches automation differently. The communications interfaces vary as well as the command language used to control the instrument.

Invasive species in the flora of Ukraine. I. The group of highly active species

Geo&Bio ◽  
2019 ◽  
Vol 2019 (17) ◽  
pp. 116-135 ◽  
Author(s):  
Vira V. Protopopova ◽  
◽  
Myroslav Shevera
Keyword(s):  
Invasive Species ◽  
Active Species ◽  
Highly Active

Identifikasi Miskonsepsi dan Tingkat Pemahaman Mahasiswa Tadris Fisika pada Materi Listrik Dinamis Menggunakan 3-Tier Diagnostic Test

2020 ◽  
Vol 3 (2) ◽  
pp. 128
Author(s):  
Lalu A. Didik ◽  
Muh. Wahyudi ◽  
Muhammad Kafrawi
Keyword(s):  
Diagnostic Test ◽  
Physics Education ◽  
Quantitative Research ◽  
Full Understanding ◽  
Study Program ◽  
Electric Voltage ◽  
Quantitative Research Methods ◽  
Physics Courses ◽  
Basic Physics ◽  
Level Of Understanding

This study aims to determine the misconceptions and level of understanding of physics education students on dynamic electricity. The method used is descriptive quantitative research methods. The research sample was 33 students of the tadris physics study program who are currently taking basic physics courses 2 even semester 2019/2020. Data collection used a 3-tier diagnostic test. In the concept of current and electric voltage, students who are included in the full understanding category are 26% and 29% understand partially with the low category and the level of misconception reaches 45%. In the concept of ohm law and electrical resistance, it was found that students with a full understanding level of 23% and partially understanding 14% were in the low category and the level of student misconception showed the largest percentage, namely 63% with the high category. In the concept of electrical circuits, students with a full understanding level of 29% and partially understanding 50% and included in the medium category with student misconceptions showed the smallest percentage was 21% with the low category. As a whole, it shows that the average level of students' understanding and misconceptions on dynamic electricity material is still low with a percentage of 26% and partial understanding is moderate with a percentage of 31% and a misconception of 43% with a moderate category. Keywords: Misconception, level of undertanding, 3-tier diagnostic, electricicity.ABSTRAK.Penelitian ini bertujuan untuk mengetahui miskonsepsi dan tingkat pemahaman mahasiswa tadris fisika pada materi listrik dinamis. Metode yang digunakan adalah metode penelitian deskriptif kuantitatif. Sampel penelitian adalah 33 orang mahasiswa program studi tadris fisika yang sedang menempuh mata kuliah fisika dasar 2 semester genap 2019/2020. Pengumpulan data menggunakan 3-tier diagnostic test. Pada konsep arus dan tegangan listrik, mahasiswa yang termasuk dalam kategori pemahaman penuh sebesar 26% dan paham sebagian sebesar 29% dengan kategori rendah dan tingkat miskonsepsi mencapai 45%. Pada konsep hukum ohm dan hambatan listrik didapatkan bahwa mahasiswa dengan tingkat pemahaman penuh sebesar 23% dan paham sebagian 14% dengan kategori rendah dan tingkat miskonsepsi mahasiswa menunjukkan persentase paling besar yaitu sebesar 63% dengan kategori tinggi. Pada konsep rangkaian listrik, mahasiswa dengan tingkat pemahaman penuh 29%, paham sebagian 50% dengan kategori sedang serta miskonsepsi mahasiswa menunjukkan persentase paling kecil yaitu 21% dengan kategori rendah. Secara kesuluruhan rata-rata tingkat pemahaman dan miskonsepsi mahasiswa pada materi listrik dinamis masih tergolong rendah dengan persentase sebesar 26% dan paham sebagian tergolong sedang dengan persentase 31% dan miskonsepsi sebesar 43% dengan kategori sedang.Kata kunci: miskonsepsi, tingkat pemahaman, 3-tier diagnostic, listrik dinamis

MicroVolt Variations of The Human Brain (Quantitative Electroencephalography) Display Differential Torque Effects During West-East versus North-South Orientation in the Geomagnetic Field

2016 ◽  
Vol 12 (2) ◽  
pp. 4255-4259
Author(s):  
Michael A Persinger ◽  
David A Vares ◽  
Paula L Corradini
Keyword(s):  
Human Brain ◽  
Geomagnetic Field ◽  
Neuronal Cell ◽  
Single Subject ◽  
Additional Energy ◽  
Actual Measurement ◽  
Neuronal Processes ◽  
Basic Physics ◽  
Order Of Magnitude ◽  
The Moment

                The human brain was assumed to be an elliptical electric dipole. Repeated quantitative electroencephalographic measurements over several weeks were completed for a single subject who sat in either a magnetic eastward or magnetic southward direction. The predicted potential difference equivalence for the torque while facing perpendicular (west-to-east) to the northward component of the geomagnetic field (relative to facing south) was 4 μV. The actual measurement was 10 μV. The oscillation frequency around the central equilibrium based upon the summed units of neuronal processes within the cerebral cortices for the moment of inertia was 1 to 2 ms which are the boundaries for the action potential of axons and the latencies for diffusion of neurotransmitters. The calculated additional energy available to each neuron within the human cerebrum during the torque condition was ~10-20 J which is the same order of magnitude as the energy associated with action potentials, resting membrane potentials, and ligand-receptor binding. It is also the basic energy at the level of the neuronal cell membrane that originates from gravitational forces upon a single cell and the local expression of the uniaxial magnetic anisotropic constant for ferritin which occurs in the brain. These results indicate that the more complex electrophysiological functions that are strongly correlated with cognitive and related human properties can be described by basic physics and may respond to specific geomagnetic spatial orientation.

Basic Physics in Color-Coded EOS Metallization Failures (Differentiating between EOS and ESD)

1998 ◽  
Author(s):  
Leo G. Henry ◽  
J.H. Mazur
Keyword(s):  
Failure Analysis ◽  
Light Microscope ◽  
Structural Changes ◽  
Surface Oxide ◽  
Aluminum Surface ◽  
Surrounding Area ◽  
Die Surface ◽  
Basic Physics ◽  
Direct Contrast ◽  
Glass Interface

Abstract The task of differentiating precisely between EOS and ESD failures continues to be a challenging one for Failure Analysis Engineers. Electrical OverStress (EOS) failures on the die surface (burnt/fused metallization) of an IC can be characterized mainly by the discoloration at the site of the failures. This is in direct contrast to the lack of discoloration characteristic of ESD failures, which occur almost exclusively below the die surface (oxide and junction failures). To aid in this distinction, this paper attempts to present the underlying physics behind the discoloration produced in the EOS failures. For the EOS failures, the metal fuses due to the longer pulse widths (sec to msec), while for the ESD failures, the silicon melts because of the shorter pulse widths (< < 500 nsec) and higher energy. After EOS, the aluminum surface becomes dark and rough and the oxide in the surrounding area becomes deformed and distorted, resulting in the discoloration observed in the light microscope. This EOS discoloration could be due to one or more of the following: 1) morphological and structural changes at the metal/glass interface and the glass itself; 2) changes in the thickness and scattering behavior of the glass and metal in the failed areas.

Studies on Cerium Electrochemistry in High Temperature Ionic Liquids

2018 ◽  
Vol 69 (1) ◽  
pp. 112-115
Author(s):  
Ana Maria Popescu ◽  
Virgil Constantin
Keyword(s):  
Molten Salts ◽  
Electrochemical Techniques ◽  
Active Species ◽  
Single Step ◽  
Cathodic Process ◽  
Molybdenum Electrode ◽  
Solute Interaction ◽  
Ohmic Drop ◽  
State Potential ◽  
Direct Discharge

The cathodic behavior of Ce3+ ions in LiF-NaF-BaF2, LiF-NaF-NaCl and NaCl-KCl molten salts at 730� C has been studied using different electrochemical techniques. The decomposition potential (Ed) and the cathodic overvoltage were determined by introducing NaCeF4 as electrochemical active species using steady-state potential-current curves recorded under galvanostatic conditions. The values of |Ed| were 1.85 V in LiF-NaF-BaF2, 2.114 V in LiF-NaF-NaCl and 2.538 V in NaCl-KCl, respectively. It was also found that the ohmic drop potential in melt is not dependent on NaCeF4 concentration and it rises as the current intensity increases. The Tafel slopes and other kinetic parameters were calculated on the assumption that the cathodic process consisted of direct discharge of Ce3+, with no solvent-solute interaction. In order to elucidate the mechanisn of cathodic process the cyclic voltammetry technique was finally used. From the evolution of the voltammograms we conclude that the electrochemical reduction of Ce3+ ion is actually a reversible process on the molybdenum electrode and cathodic reduction of Ce3+ takes place in one single step involving three electron exchange. Our study adds to the accumulating data and confirms available results of electrodeposition of metalic cerium from molten salts using NaCeF4 as solute.

Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Ros ◽  
C. Canals-Batlle ◽  
M.A. Lillo-Ródenas ◽  
E. Fuente ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Room Temperature ◽  
Waste Water Treatment ◽  
Textural Properties ◽  
Active Species ◽  
Elemental Sulphur ◽  
Gaseous Emissions ◽  
Removal Experiments ◽  
Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

Enhancement of hydroxyl radical generation by phenols and their reaction intermediates during ozonation

1998 ◽  
Vol 38 (6) ◽  
pp. 147-154 ◽  
Author(s):  
Hideo Utsumi ◽  
Sang-Kuk Han ◽  
Kazuhiro Ichikawa
Keyword(s):  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Spin Trapping ◽  
Active Species ◽  
Generation Rate ◽  
Peak Height Ratio ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Phenol Derivatives ◽  
Semiquinone Radicals

Generation of hydroxyl radicals, one of the major active species in ozonation of water was directly observed with a spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrrolineN-oxide (DMPO) as a spin-trapping reagent. Hydroxyl radical were trapped with DMPO as a stable radical, DMPO-OH. Eighty μM of ozone produced 1.08 X 10-6M of DMPO-OH, indicating that 1.4% of •OH is trapped with DMPO. Generation rate of DMPO-OH was determined by ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance •OH generation during ozonation of water. Ozonation of 2,3-, 2,5-, 2,6-dichlorophenol gave an ESR spectra of triplet lines whose peak height ratio were 1:2:1. ESR parameters of the triplet lines agreed with those of the corresponding dichloro-psemiquinone radical. Ozonation of 2,4,5- and 2,4,6-trichlorophenol gave the same spectra as those of 2,5- and 2,6-dichlorophenol, respectively, indicating that a chlorine group in p-position is substituted with a hydroxy group during ozonation. Amounts of the radical increased in an ozone-concentration dependent manner and were inhibited by addition of hydroxyl radical scavengers. These results suggest that p-semiquinone radicals are generated from the chlorophenols by hydroxyl radicals during ozonation. The p-semiquinone radicals were at least partly responsible for enhancements of DMPO-OH generation.

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