Mechanism and its Mathematical Expressions of Stress-Induced Light Emission of ZnS:Mn/Polyester Composite

2017 ◽  
Vol 728 ◽  
pp. 252-257
Author(s):  
Sirichai Leelachao ◽  
Shinji Muraishi ◽  
Yoshio Nakamura

Mechanism of mechanoluminescence of the composite of Mn-doped ZnS particles and polyester resin is developed based on the principle of Fermi-level shift, associated by piezoelectric effect. As the electron-hole recombination is responsible for light emission, it is possible to determine the number of emitted photons from the difference in number of conducting electrons between the stressed state and the thermal equilibrium condition. For the given emission color, characteristics of photomultiplier tube and deformation conditions, the emitted photons can be approximated. The model is expressed as A[exp (Bσ2) - 1] where σ is the applied stress, a pre-exponential A illustrates the efficiency of luminescent centers and the influences of dielectric and piezoelectric constants of ZnS host and temperature are displayed as the exponent factor B.

Author(s):  
Danilo Golijanin

Emission of visible light from forward and reverse biased silicon p-n junctions due to the radiative electron-hole recombination has been known since the mid-50s. The weak light emission was also seen from a silicon-dioxide dielectric in an integrated gate oxide capacitor formed between a polysilicon gate and an (n or p) well in an integrated circuit. The difference in carrier energies for each of these recombination mechanisms gives rise to a specific photon wavelength (energy) distribution in the visible range. All photoemitting events are characterized by a very low level light intensity due to the low quantum efficiency of about 10−5 - 10−4 photons per one electron-hole recombination.The first practical photoemission microscope was constructed by Khurana and Chiang. They took the advantage of the advances in night vision technology and used it for imaging the faint ("invisible") light coming from various silicon structures. A typical photoemission microscope consists of an x-y-z stage with the device holder, an optical microscope, a lightsensitive camera all set within a light-tight enclosure and a computer system for image acquisition and processing.


Author(s):  
Olga Mashukova ◽  
Olga Mashukova ◽  
Yuriy Tokarev ◽  
Yuriy Tokarev ◽  
Nadejda Kopytina ◽  
...  

We studied for the first time luminescence characteristics of the some micromycetes, isolated from the bottom sediments of the Black sea from the 27 m depth. Luminescence parameters were registered at laboratory complex “Svet” using mechanical and chemical stimulations. Fungi cultures of genera Acremonium, Aspergillus, Penicillium were isolated on ChDA medium which served as control. Culture of Penicillium commune gave no light emission with any kind of stimulation. Culture of Acremonium sp. has shown luminescence in the blue – green field of spectrum. Using chemical stimulation by fresh water we registered signals with luminescence energy (to 3.24 ± 0.11)•108 quantum•cm2 and duration up to 4.42 s, which 3 times exceeded analogous magnitudes in a group, stimulated by sea water (p < 0.05). Under chemical stimulation by ethyl alcohol fungi culture luminescence was not observed. Culture of Aspergillus fumigatus possessed the most expressed properties of luminescence. Stimulation by fresh water culture emission with energy of (3.35 ± 0.11)•108 quantum•cm2 and duration up to 4.96 s. Action of ethyl alcohol to culture also stimulated signals, but intensity of light emission was 3–4 times lower than under mechanical stimulation. For sure the given studies will permit not only to evaluate contribution of marine fungi into general bioluminescence of the sea, but as well to determine places of accumulation of opportunistic species in the sea.


2008 ◽  
Vol 43 (No. 3) ◽  
pp. 87-96 ◽  
Author(s):  
A. Dreiseitl

The results of evaluation of powdery mildew resistance in winter barley varieties in 285 Czech Official Trials conducted at 20 locations were analysed. Over the period, the number of varieties tested per year increased from four to seven in 1976−1985 to 53−61 in 2002−2005. To assess the resistance of varieties, only trials with sufficient disease severity were used. In 1976−2000, six varieties (1.7% of the varieties tested in the given years) ranked among resistant (average resistance of a variety in a year > 7.5) including NR-468 possessing the gene <i>Mla13</i>, KM-2099 with <i>mlo</i> and Marinka with the genes <i>Mla7</i>, <i>MlaMu2</i>. In 2001−2005, already 33 varieties (16.9%) ranked among resistant, of which Traminer possessing the genes <i>Ml(St)</i> and <i>Ml(IM9 </i> dominated. The proportion of susceptible varieties (average resistance ≤ 5.5) did not change in the two mentioned periods. Two-rowed varieties began to be tested as late as in 1990 (the first variety was Danilo), however, no difference was found in the resistance of two- and six-rowed varieties. Using an example of two pairs of varieties (Dura-Miraj and Marinka-Tiffany) with identical genes for specific resistance but with different resistance in the field, the efficiency of non-specific resistance is discussed. The resistance of domestic and foreign varieties was similar in 1994−2000; however, in 2001−2005 the difference was 0.75 point to disadvantage of domestic ones.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2303
Author(s):  
Silvana De Iuliis ◽  
Roberto Dondè ◽  
Igor Altman

The application of pyrometry to retrieve particle temperature in particulate-generating flames strictly requires the knowledge of the spectral behavior of emissivity of light-emitting particles. Normally, this spectral behavior is considered time-independent. The current paper challenges this assumption and explains why the emissivity of oxide nanoparticles formed in flame can change with time. The suggested phenomenon is related to transitions of electrons between the valence and conduction energy bands in oxides that are wide-gap dielectrics. The emissivity change is particularly crucial for the interpretation of fast processes occurring during laser-induced experiments. In the present work, we compare the response of titania particles produced by a flame spray to the laser irradiation at two different excitation wavelengths. The difference in the temporal behavior of the corresponding light emission intensities is attributed to the different mechanisms of electron excitation during the laser pulse. Interband transitions that are possible only in the case of the laser photon energy exceeding the titania energy gap led to the increase of the electron density in the conduction band. Relaxation of those electrons back to the valence band is the origin of the observed emissivity drop after the UV laser irradiation.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuejian Ma ◽  
Fei Zhang ◽  
Zhaodong Chu ◽  
Ji Hao ◽  
Xihan Chen ◽  
...  

AbstractThe outstanding performance of organic-inorganic metal trihalide solar cells benefits from the exceptional photo-physical properties of both electrons and holes in the material. Here, we directly probe the free-carrier dynamics in Cs-doped FAPbI3 thin films by spatiotemporal photoconductivity imaging. Using charge transport layers to selectively quench one type of carriers, we show that the two relaxation times on the order of 1 μs and 10 μs correspond to the lifetimes of electrons and holes in FACsPbI3, respectively. Strikingly, the diffusion mapping indicates that the difference in electron/hole lifetimes is largely compensated by their disparate mobility. Consequently, the long diffusion lengths (3~5 μm) of both carriers are comparable to each other, a feature closely related to the unique charge trapping and de-trapping processes in hybrid trihalide perovskites. Our results unveil the origin of superior diffusion dynamics in this material, crucially important for solar-cell applications.


Author(s):  
Harald Fripertinger ◽  
Jens Schwaiger

AbstractIt was proved in Forti and Schwaiger (C R Math Acad Sci Soc R Can 11(6):215–220, 1989), Schwaiger (Aequ Math 35:120–121, 1988) and with different methods in Schwaiger (Developments in functional equations and related topics. Selected papers based on the presentations at the 16th international conference on functional equations and inequalities, ICFEI, Bȩdlewo, Poland, May 17–23, 2015, Springer, Cham, pp 275–295, 2017) that under the assumption that every function defined on suitable abelian semigroups with values in a normed space such that the norm of its Cauchy difference is bounded by a constant (function) is close to some additive function, i.e., the norm of the difference between the given function and that additive function is also bounded by a constant, the normed space must necessarily be complete. By Schwaiger (Ann Math Sil 34:151–163, 2020) this is also true in the non-archimedean case. Here we discuss the situation when the bound is a suitable non-constant function.


2005 ◽  
Vol 108-109 ◽  
pp. 755-760 ◽  
Author(s):  
Wolfgang Skorupa ◽  
J.M. Sun ◽  
S. Prucnal ◽  
L. Rebohle ◽  
T. Gebel ◽  
...  

Using ion implantation different rare earth luminescent centers (Gd3+, Tb3+, Eu3+, Ce3+, Tm3+, Er3+) were formed in the silicon dioxide layer of a purpose-designed Metal Oxide Silicon (MOS) capacitor with advanced electrical performance, further called a MOS-light emitting device (MOSLED). Efficient electroluminescence was obtained for the wavelength range from UV to infrared with a transparent top electrode made of indium-tin oxide. Top values of the efficiency of 0.3 % corresponding to external quantum efficiencies distinctly above the percent range were reached. The electrical properties of these devices such as current-voltage and charge trapping characteristics, were also evaluated. Finally, application aspects to the field of biosensing will be shown.


Author(s):  
C Sun ◽  
D Guo ◽  
H Gao ◽  
L Zou ◽  
H Wang

In order to manage the version files and maintain the latest version of the computer-aided design (CAD) files in asynchronous collaborative systems, one method of version merging for CAD files is proposed to resolve the problem based on feature extraction. First of all, the feature information is extracted based on the feature attribute of CAD files and stored in a XML feature file. Then, analyse the feature file, and the feature difference set is obtained by the given algorithm. Finally, the merging result of the difference set and the master files with application programming interface (API) interface functions is achieved, and then the version merging of CAD files is also realized. The application in Catia validated that the proposed method is feasible and valuable in engineering.


Author(s):  
Shibnath Mukherjee ◽  
Aryya Gangopadhyay ◽  
Zhiyuan Chen

While data mining has been widely acclaimed as a technology that can bring potential benefits to organizations, such efforts may be negatively impacted by the possibility of discovering sensitive patterns, particularly in patient data. In this article the authors present an approach to identify the optimal set of transactions that, if sanitized, would result in hiding sensitive patterns while reducing the accidental hiding of legitimate patterns and the damage done to the database as much as possible. Their methodology allows the user to adjust their preference on the weights assigned to benefits in terms of the number of restrictive patterns hidden, cost in terms of the number of legitimate patterns hidden, and damage to the database in terms of the difference between marginal frequencies of items for the original and sanitized databases. Most approaches in solving the given problem found in literature are all-heuristic based without formal treatment for optimality. While in a few work, ILP has been used previously as a formal optimization approach, the novelty of this method is the extremely low cost-complexity model in contrast to the others. They implement our methodology in C and C++ and ran several experiments with synthetic data generated with the IBM synthetic data generator. The experiments show excellent results when compared to those in the literature.


2021 ◽  
Vol 7 (1) ◽  
pp. 15
Author(s):  
Robiatul Munajah ◽  
Asep Supena

The success of students in learning does not only depend on their own abilities. Several factors that can give effect need to be optimized. The teacher's strategy is very meaningful to optimize students' multiple intelligences according to the indicators that each student has. Every child in this world has various intelligences in different levels and indicators. This shows that all children, by nature, are intelligent. The difference lies in the level and indicators of intelligence. These differences are determined by various factors. One of them is the stimulation given when children learn in the learning process carried out by the teacher. The difference in intelligence among students demands a fair and existential way of thinking of educators. This research is a literature review to see more specifically the teacher's strategy in optimizing multiple intelligences in elementary schools based on research reference sources and books. Good educators are able to detect children's intelligence by observing the behavior, tendencies, interests, ways and qualities of children when reacting to the given stimulus. All indicators of intelligence can be recognized by educators to then make a profile of intelligence. Therefore, every teacher should know how to develop the intelligence of their students, by identifying each indicator of children's intelligence and realizing the importance of developing all the intelligences of their students. 


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