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Tytuł:
Crystal Structure of K$\text{}_{3}$Na(SeO$\text{}_{4}$)$\text{}_{2}$ at 340 K
Autorzy:
Fukami, T.
Chen, R. H.
Powiązania:
https://bibliotekanauki.pl/articles/1993089.pdf
Data publikacji:
1998-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.66.Fn
64.60.Fr
Opis:
The crystal structure of tripotassium sodium diselenate, K$\text{}_{3}$Na(SeO$\text{}_{4}$)$\text{}_{2}$, at 340 K is studied by single-crystal X-ray diffraction. The space group symmetry (trigonal P3̅) and structure parameters are determined. It is found that there exists the difference of the direction and the magnitude of the atomic displacement at the two phase transitions of 346 K and 334 K.
Źródło:
Acta Physica Polonica A; 1998, 94, 5-6; 795-801
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Phase Transition and Crystal Structure for (ND$\text{}_{4}$)$\text{}_{4}$D$\text{}_{2}$(SeO$\text{}_{4}$)$\text{}_{3}$ at Low Temperature
Autorzy:
Fukami, T.
Chen, R. H.
Powiązania:
https://bibliotekanauki.pl/articles/2027434.pdf
Data publikacji:
2001-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.66.Fn
64.60.Fr
Opis:
Differential scanning calorimetry and X-ray diffraction measurements were performed on a deuterated tetraammonium dihydrogen triselenate (ND$\text{}_{4}$)$\text{}_{4}$D$\text{}_{2}$(SeO$\text{}_{4}$)$\text{}_{3}$ crystal at low temperatures. A structural phase transition is found at 182.0(3) K. The space group symmetry (triclinic P1) and the structure parameters are determined at 145 K in the low-temperature phase. The isotope effect for an asymmetric O-H-O hydrogen bond by the substitution of deuterium is discussed.
Źródło:
Acta Physica Polonica A; 2001, 100, 1; 53-65
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Study of (NH$\text{}_{4}$)$\text{}_{4}$H$\text{}_{2}$(SeO$\text{}_{4}$)$\text{}_{3}$ in the Low-Temperature Phase
Autorzy:
Fukami, T.
Higa, N.
Chen, R. H.
Powiązania:
https://bibliotekanauki.pl/articles/2013261.pdf
Data publikacji:
2000-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.66.Fn
64.60.Fr
Opis:
The crystal structure of tetraammonium dihydrogen triselenate, (NH$\text{}_{4}$)$\text{}_{4}$H$\text{}_{2}$(SeO$\text{}_{4}$)$\text{}_{3}$, in the low-temperature phase at 141 K is studied by X-ray diffraction. The space group symmetry (triclinic P1) and the structure parameters are determined. By the shift of the Se atom from the center of the SeO$\text{}_{4}$ tetrahedron, it is suggested that the (NH$\text{}_{4}$)$\text{}_{4}$H$\text{}_{2}$ (SeO$\text{}_{4}$)$\text{}_{3}$ crystal in the low-temperature phase is ferroelectric with the electric dipole moment along the c-axis. The rotation of the SeO$\text{}_{4}$ tetrahedron suggested by electron paramagnetic resonance measurements is discussed.
Źródło:
Acta Physica Polonica A; 2000, 97, 4; 663-670
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Iterative estimators of parameters in linear models with partially variant coefficients
Autorzy:
Hu, S.
Meinke, K.
Chen, R.
Huajiang, O.
Powiązania:
https://bibliotekanauki.pl/articles/929607.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
model liniowy
estymacja parametrów
algorytm iteracyjny
współczynnik zmienności
linear model
parameter estimation
iterative algorithms
variant coefficients
Opis:
A new kind of linear model with partially variant coefficients is proposed and a series of iterative algorithms are introduced and verified. The new generalized linear model includes the ordinary linear regression model as a special case. The iterative algorithms efficiently overcome some difficulties in computation with multidimensional inputs and incessantly appending parameters. An important application is described at the end of this article, which shows that this new model is reasonable and applicable in practical fields.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2007, 17, 2; 179-187
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation separation of scheelite from calcite using sodium polyacrylate as depressant
Autorzy:
Zhang, Y.
Chen, R.
Li, Y.
Wang, Y.
Luo, X.
Powiązania:
https://bibliotekanauki.pl/articles/110896.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
scheelite
calcite
flotation
sodium polyacrylate
selective depression
Opis:
The depressing properties of sodium polyacrylate (PA-Na) for calcite from scheelite were studied by microflotation experiments, zeta potentials, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation. Flotation results revealed that the selective depression effect of PA-Na was better than that of sodium silicate (Na2SiO3), and PA-Na can depress calcite more effectively than scheelite. The flotation recovery of scheelite and calcite kept at about 75% and 15% respectively at the pulp pH 9.3~9.6 and PA-Na concentration from 37.5 mg/dm3 to 50 mg/dm3. The zeta potentials of the minerals were significantly altered and the zeta potential of calcite became more negative than scheelite. XPS analysis deduced the occurrence of chemisorption between PA-Na and mineral surfaces, and the chemisorption of PA-Na on calcite was stronger than on scheelite. The results from DFT calculation demonstrated that the absolute value of the adsorption energy in the presence of PA-Na on the surface of calcite {104} was larger than on the surface of scheelite {111}. With the combination of the analysis, it could be concluded that calcite was more easily depressed than scheelite, and this finding remarkably matched with the microflotation experimental results. Furthermore, by using PA-Na as depressant, the flotation separation of scheelite from calcite can be achieved by controlling the flotation pH and PA-Na dosage.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 505-516
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Image compression-encryption algorithm combining compressive sensing with log operation
Autorzy:
Chen, R.-L.
Zhou, Y.
Luo, M.
Zhang, A.-D.
Gong, L.-H.
Powiązania:
https://bibliotekanauki.pl/articles/174009.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image encryption
image compression
compressive sensing
log operation
Opis:
Based on compressive sensing and log operation, a new image compression-encryption algorithm is proposed, which accomplishes encryption and compression simultaneously. The proposed image compression-encryption algorithm takes advantage of not only the physical realizability of partial Hadamard matrix, but also the resistance of the chosen-plaintext attack since all the elements in the partial Hadamard matrix are 1, –1 or log 1 = 0. The proposed algorithm is sensitive to the key and it can resist various common attacks. The simulation results verify the validity and reliability of the proposed image compression-encryption algorithm.
Źródło:
Optica Applicata; 2018, 48, 4; 563-573
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In vitro cloning potential and phytochemical evaluations of aneuploid individuals produced from reciprocal crosses between diploid and triploid in Echinacea purpurea L.
Autorzy:
Li, Q.
Jiang, W.
Ren, Y.
Chen, R.
Li, X.
Yang, Y.
Wu, H.
Powiązania:
https://bibliotekanauki.pl/articles/58769.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Botaniczne
Opis:
Aneuploidy often presents large variations in morphology, physiology, biochemistry, and genetics owing to karyotypic imbalance. This study aimed to evaluate the efficacy of aneuploid breeding in Echinacea purpurea L, an important medicinal plant. Reciprocal crosses between diploid and triploid plants were performed to generate aneuploid plants. Cross with triploid as female parent resulted in increased production of aneuploid individuals (19 of 23; 82.61%), while using diploid as female parent yielded much higher percentage of diploid progenies (130 of 133; 97.74%). Each aneuploid had particular karyotypic characteristics compared to the parents. The proportions of median, submedian, and subterminal centromere location chromosomes in gross chromosomes among aneuploids and two parents showed large variations. Although aneuploids had relatively lower adventitious bud regeneration rates than their parents, almost half of them looked morphologically normal, with high survival rates when transplanted to ex vitro conditions. Among the bioactive compounds assessed, cichoric acid and chlorogenic acid contents were extremely encouraging. Most aneuploids had higher cichoric acid and chlorogenic acid contents than their parents. For example, A2 had the highest cichoric acid content of 21.98 mg/g dry weight, more than twice the values of diploid and triploid. Meanwhile, A21 had the highest chlorogenic acid content of 1.84 mg/g, approximately five times more than the parental values. Eleven superior aneuploid lines were successfully screened as breeding candidates. The present findings indicated E. purpurea is highly tolerant of karyotypic imbalance and aneuploid plants could serve as prospective breeding resources in E. purpurea.
Źródło:
Acta Societatis Botanicorum Poloniae; 2017, 86, 3
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Requirement for and Use of Coated P92 Steel for Enhanced Structural Integrity at High Temperature
Autorzy:
Hoey, T.
Chen, R.
McCartney, D.
Sun, W.
Mansfield, J.
Barnard, P.
Foster, J.
Powiązania:
https://bibliotekanauki.pl/articles/1402066.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.15.Pq
68.37.-d
61.05.-a
64.75.-g
Opis:
To achieve climate change targets and to improve the efficiency of fossil fuel power plant the temperature and pressure of operation must be increased. With steam temperatures predicted to rise by 50-100 K in the next 30 years, this presents a number of material challenges, not least for the ferritic steels used for steam pipework. Currently the best in class ferritic steel for power plant steam pipework is P92, a 9-12% Cr advanced martensitic steel that was developed for its superior high temperature creep resistance. This paper will give a brief overview of P92 microstructure, composition and metallurgy and identify experimentally and computationally some key features of the material. As well as failure by creep, P92 at high temperature also suffers from steam oxidation damage. Recent literature suggests that coatings applied to P92 are a very promising solution. A short review of previous work on steam oxidation resistant coatings for P92 is included. A novel Co-Cr-C coating that has not previously been explored for this application is described. Experimental and computational characterisation is included.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 514-519
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-Pressure Studies of Semiconductors in the Far-Infrared: Donor States in Quasi-2D
Autorzy:
Weinstein, B. A.
Tischler, J. G.
Chen, R. J.
Nickel, H. A.
McCombe, B. D.
Dzyubenko, A. B.
Sivachenko, A.
Powiązania:
https://bibliotekanauki.pl/articles/2014129.pdf
Data publikacji:
2000-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Fd
73.20.Dx
73.20.Hb
Opis:
We review recent experimental advances by the Buffalo group in performing far-infrared magnetospectroscopy under fine tuning of applied high hydrostatic pressure. Experiments are reported for the effects of pressure on Si donors in modulation doped GaAs/AlGaAs quantum wells. We clearly observe pressure-mediated competition between free (i.e., Landau level) and bound electron states - the latter arising from both neutral (D$\text{}^{0}$) and charged (D$\text{}^{-}$) donor species. With increasing pressure, there is a progression of the observed spectra from being dominated by cyclotron resonance and the D$\text{}^{-}$ singlet (or singlet-like bound magnetoplasmon) transitions, to showing the D$\text{}^{0}$ 1s → 2p$\text{}^{+}$ line. The main reason for this evolution is the decrease in electrons due to the crossover of the Si levels associated with the Γ (well) and X (barrier) conduction minima. Indeed, for pressures above 30 kbar the Γ(well)-X(barrier) crossover quenches all the transitions. However, we find strong evidence that electrons are independently lost to a trap, which becomes active several kbar below this crossing. A possible candidate for this trap is residual Se impurities in the barriers. We present the results of detailed numerical calculation which are found to agree very well with the measured field dependencies of the cyclotron resonance, D$\text{}^{0}$ and D$\text{}^{-}$ transition energies. In the sample with the highest doping, a new transition is observed for fields and pressures above 7.5 T and 5 kbar. Reasons for this apparent anomaly are discussed.
Źródło:
Acta Physica Polonica A; 2000, 98, 3; 241-257
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Isolation and sequence analysis of the complete VP2 gene of canine parvovirus from Chinese domestic pets and determination of the pathogenesis of these circulating strains in beagles
Autorzy:
Chen, M.R.
Guo, X.Y.
Wang, Z.Y.
Jiang, Y.T.
Yuan, W.F.
Xin, T.
Hou, S.H.
Song, T.Q.
Lin, W.D.
Zhu, H.F.
Jia, H.
Powiązania:
https://bibliotekanauki.pl/articles/2087542.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
canine parvovirus
molecular epidemiology
phylogenetic analysis
pathogenesis
Źródło:
Polish Journal of Veterinary Sciences; 2019, 2; 287-296
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Praktyczne podejście do oceny niezawodności aplikacji sieciowych
A practical approach for network application reliability assessment
Autorzy:
Li, R.
Kang, R.
Huang, N.
Chen, W.
Chen, Y.
Powiązania:
https://bibliotekanauki.pl/articles/301438.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
sieci
niezawodność
ocena
aplikacje
network
reliability
assessment
applications
Opis:
Wiele różnych aplikacji może być obsługiwanych przez tę samą sieć. Wymagania użytkowników i kryteria uszkodzeń mogą być odmienne dla różnych aplikacji. Ocena sieci winna być przeprowadzana z punktu widzenia aplikacji. W niniejszym artykule, zaproponowano metodologię oceny niezawodności aplikacji sieciowych opartą na indeksach warstwowych (layered indices). Pierwszym krokiem w omawianej metodzie jest osobne obliczenie niezawodności poszczególnych aplikacji w sieci. Następnie ocenia się niezawodność sieci biorąc pod uwagę związki pomiędzy różnymi aplikacjami. Jako swój wkład niniejszy artykuł (1) przedstawia naukową i praktyczną metodę oceny niezawodności aplikacji sieciowych; (2) tworzy hierarchiczną strukturę do oceny niezawodności aplikacji sieciowych; (3) proponuje i analizuje cztery kluczowe technologie-doboru komponentów, upraszczania sieci, modelowania profilu aplikacji oraz oceny niezawodności aplikacji; (44) ilustruje proponowany proces oceny na przykładzie sieci komputerowej.
Many different applications may be handled by the same network. For different applications, the user requirements and failure criterions may be different. The network reliability assessment needs to be conducted from the "application" point of view. In this paper, a methodology for network application reliability assessment based on layered indices is proposed. Firstly, the individual application reliability is calculated for each application on the network. Then the network reliability is evaluated considering the relationships among different applications. The contributions of this paper are: (1) a scientific and practical network application reliability assessment method is proposed based on network applications; (2) a hierarchical structure for network application reliability assessment is constructed; (3) four key technologies, component selection, network simplification, application profile modeling, and application reliability assessment, are proposed and analyzed; (44) a computer network is used to illustrate the proposed assessment process.
Źródło:
Eksploatacja i Niezawodność; 2009, 4; 17-27
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of treating lettuce (Lactuca sativa L.) seeds with solutions of ethereal oils from camphor tree (Cinnamomum camphora L.) and patchouli plant (Pogostemon cablin Benth.) on their germination
Wpływ traktowania nasion sałaty (Lactuca sativa L.) roztworami olejków eterycznych z drzewa kamforowego (Cinnamomum camphora L.) i paczuli (Pogostemon cablin Benth.) na ich kiełkowanie
Autorzy:
Chen, W.
Hołubowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/11541931.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
Cinnamomum camphora
Lactuca sativa
Pogostemon cablin
aetherolea zob.essential oil
camphor tree
essential oil
ethereal oil zob.essential oil
germination
lettuce
patchouli plant
seed
seed germination
solution
volatile oil zob.essential oil
seed quality
seed infestation
fungi
Opis:
One of the most important problems in horticultural seed science and technology nowadays is looking for new methods to improve seed quality. Especially interesting are the ones, in which compounds of natural origin are used. One of such groups is ethereal oils from plants. The commercial seed samples of lettuce (Lactuca sativa L. ‘Dumka’) were soaked in 9 different treatments of 5% alcoholic solution of camphor tree (Cinnamomum camphora L.) ethereal oil and 9 different treatments of 5% alcoholic solution of patchouli plant (Pogostemon cablin Benth.) ethereal oil. Then the seeds were routinely tested for seed germination, the length of the received seedlings was also measured and the seeds health status was evaluated. The tested ethereal oils had no effect on the germination of lettuce seeds. However, soaking the seeds in the ethereal oils solutions did decrease the percentage of dead seeds in the tested samples. Soaking of the seeds in the ethereal oils solutions also increased the percentage of healthy ungerminated seeds. Treating the seeds with the concentrations of the ethereal oils solutions, although had no effect on their germination, still shortened the length of seedlings. Moreover, the used ethereal oils lowered the amount of identified Alternaria alternata and Cladosporium sphaerospermum fungi on the seeds.
Jednym z najważniejszych problemów nasiennictwa ogrodniczego dziś jest poszukiwanie nowych metod poprawy jakości nasion. Szczególnie interesujące są te z nich, w których wykorzystuje się substancje naturalne. Jedną z takich grup są olejki eteryczne z roślin. Nasiona handlowe sałaty (Lactuca sativa L.) odmiany Dumka potraktowano na 9 różnych sposobów 5% alkoholowym roztworem olejku eterycznego z drzewa kamforowego (Cinnamomum camphora L.) i na 9 różnych sposobów 5% alkoholowym roztworem olejku eterycznego z paczuli (Pogostemon cablin Benth.). Następnie nasiona poddano rutynowej ocenie kiełkowania, zmierzono długość otrzymanych siewek i oceniono zdrowotność nasion. Badane olejki eteryczne nie wpłynęły na kiełkowanie nasion sałaty, natomiast zmniejszyły odsetek martwych nasion w badanych próbach. Moczenie nasion w badanych roztworach olejków zwiększyło także odsetek nasion zdrowych niekiełkujących. Traktowanie nasion roztworami olejków eterycznych o wyższych stężeniach, choć nie wpłynęło na ich kiełkowanie, to jednak skróciło długość otrzymanych z nich siewek. Ponadto stosowane olejki eteryczne obniżyły ilość oznaczonych na nasionach grzybów: Alternaria alternata i Cladosporium sphaerospermum.
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2010, 09, 3; 69-83
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo based angular analysis of multiple scattered photons for underwater optical imaging
Autorzy:
Li, S.
Wang, R.
Chen, G.
Powiązania:
https://bibliotekanauki.pl/articles/173322.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
underwater imaging
turbid media
Monte Carlo method
multiple scattering
Opis:
Image contrast and visibility associated with underwater optical imaging systems are usually degraded by the absorbing and scattering effects of turbid waters. To improve the image contrast, laser-range-gate has been widely applied to underwater optical imaging systems. The work of Katsev et al. (Appl.Opt. 38(33), 1999, pp. 6849–6858) shows that the contrast of a shadow image is greater than that of the object image. The present paper outlines a Monte Carlo based simulation method of image formation for underwater optical imaging. It is found that the contrast of a shadow image varies with gate starting depths. The angular distribution of multiply scattered photons is obtained via semi-analytical models (Shengfu Li et al., Opt.Commun. 381, 2016, pp. 43–47). The simulated results show that increasing the gate starting depth can reduce the highly backscattered photons, thus can improve the image contrast.
Źródło:
Optica Applicata; 2018, 48, 2; 237-247
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault tolerant control of switched nonlinear systems with time delay under asynchronous switching
Autorzy:
Xiang, Z.
Wang, R.
Chen, Q.
Powiązania:
https://bibliotekanauki.pl/articles/929592.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
opóźnienie czasowe
sterowanie tolerujące uszkodzenia
układ komutowany
układ nieliniowy
time delay
fault tolerant control
switched nonlinear systems
asynchronous switching
Opis:
This paper investigates the problem of fault tolerant control of a class of uncertain switched nonlinear systems with time delay under asynchronous switching. The systems under consideration suffer from delayed switchings of the controller. First, a fault tolerant controller is proposed to guarantee exponentially stability of the switched systems with time delay. The dwell time approach is utilized for stability analysis and controller design. Then the proposed approach is extended to take into account switched time delay systems with Lipschitz nonlinearities and structured uncertainties. Finally, a numerical example is given to illustrate the effectiveness of the proposed method.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2010, 20, 3; 497-506
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An LPV pole-placement approach to friction compensation as an FTC problem
Autorzy:
Patton, R. J.
Chen, L.
Klinkhieo, S.
Powiązania:
https://bibliotekanauki.pl/articles/331466.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
układ liniowy niestacjonarny
detekcja uszkodzeń
diagnostyka uszkodzeń
liniowa nierówność macierzowa
lokowanie biegunów
friction
linear parameter varying
fault detection
fault diagnosis
linear matrix inequality
pole placement
Opis:
The concept of combining robust fault estimation within a controller system to achieve active Fault Tolerant Control (FTC) has been the subject of considerable interest in the recent literature. The current study is motivated by the need to develop model-based FTC schemes for systems that have no unique equilibria and are therefore difficult to linearise. Linear Parameter Varying (LPV) strategies are well suited to model-based control and fault estimation for such systems. This contribution involves pole-placement within suitable LMI regions, guaranteeing both stability and performance of a multi-fault LPV estimator employed within an FTC structure. The proposed design strategy is illustrated using a nonlinear two-link manipulator system with friction forces acting simultaneously at each joint. The friction forces, regarded as a special case of actuator faults, are estimated and their effect is compensated within a polytope controller system, yielding a robust form of active FTC that is easy to apply to real robot systems.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 1; 149-160
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3D laser scanning technique for the inspection and monitoring of railway tunnels
Technika skanowania laserowego 3D do kontroli i monitorowania tuneli kolejowych
Autorzy:
Chen, H-M.
Ulianov, C.
Shaltout, R.
Powiązania:
https://bibliotekanauki.pl/articles/375282.pdf
Data publikacji:
2015
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
railway tunnel
inspection of railway tunnels
monitoring of railway tunnels
laser scanning
tunel kolejowy
inspekcja tuneli kolejowych
monitorowanie tuneli kolejowych
skanowanie laserowe
Opis:
Railway tunnel inspection and monitoring has predominantly been a visual and manual procedure, which is time-consuming and subjective, giving rise to variance in standards and quality. Thus, alternative, novel, automated techniques need to be developed, for more efficient and reliable tunnel examination. The reported research aimed to investigate the application of a laser scanning technique for the inspection of tunnel degradation and structural integrity. The proposed method may either substitute or supplement traditional survey techniques, being more efficient, and contributing thus to the standardisation of tunnel inspections. For the purpose of investigating the applicability and accuracy of laser scanning in tunnels, a set of tunnel lining models was constructed for laboratory tests, with the objective of determining the quality of the imaging. Initial tests were carried out using a performant laser scanner and demonstrated the feasibility of the concept. As a result, refined laboratory models were built, and experiments conducted, to establish the quality and precision of laser scanning imaging, for condition monitoring of tunnels. The experimental results indicate that the laser scanning technique used in this research has high potential for detecting the tunnel condition, monitoring the depth of weathered mortar, spalling bricks etc. with high accuracy in static scanning mode.
Kontrola i monitoring tuneli kolejowych w przeważającej mierze to procedura, która jest czasochłonna i subiektywna, co powoduje zróżnicowanie standardów i jakości badań. Stąd też muszą być opracowane alternatywe, nowoczesne, zautomatyzowane techniki do bardziej skutecznych i rzetelnych badań. Przedstawione badania miały na celu wskazanie zastosowania techniki skanowania laserowego do kontroli degradacji tunelu i integralności strukturalnej. Proponowana metoda może zastąpić, bądź uzupełnienić, tradycyjne techniki pomiarowe. Jest ona bardziej wydajna i może przyczynić się do standaryzacji kontroli tuneli. Aby zbadać przydatności i dokładności skanowania laserowego w tunelach, skonstruowano zestaw modeli do testów labolatoryjnych, w celu określenia jakości obrazów. Wyniki doświadczalne wskazują, że technika skanowania laserowego zastosowana w badaniu ma wysoki potencjał do charakteryzowania stanu tunelu, monitorowania głębokości zwietrzenia zaprawy, odpryskiwania cegieł itp., z dużą dokładnością w trybie statycznym skanowania.
Źródło:
Transport Problems; 2015, T. 10, z. spec.; 73-84
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Toluene Mono-nitration in a Semi-batch Reactor
Autorzy:
Chen, L. P.
Chen, W. P.
Liu, Y.
Peng, J. H.
Liu, R. H.
Powiązania:
https://bibliotekanauki.pl/articles/358853.pdf
Data publikacji:
2008
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
toluene mono-nitration
apparent activation energy
semi-batch reaction
thermal hazard
Opis:
Toluene mono-nitration in a semi-batch reactor was investigated with reaction calorimeter (RC1). The mixed acid HNO3/H2SO4/H2O (wt%) was used in proportion 13/66/21, which is similar to industrial parameters. The exothermic rates at different reaction temperatures were compared, and then the curves of heat generation rate after dosing were analyzed. The Maximal Temperature attainable by runaway of the desired Synthetic Reaction (MTSR) under different conditions were calculated for the course hazard evaluation. The results showed that the average reaction heat of mono-nitration was between 169.07~177.11 kJ mol-1, and the special heat of reactant was about 2 kJ kg-1 K-1. Average Ea of second order kinetic was about 30 kJ mol-1, and reaction rate was 10-4 mol s-1 l-1 order of magnitude when the strength of sulphuric acid was about 73.5%. It was also found that when temperature or stirring speed increases, the potential heat accumulation decreases.
Źródło:
Central European Journal of Energetic Materials; 2008, 5, 2; 37-47
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metoda oceny niezawodności sieci oparta na aplikacjach i strukturze topologicznej
A network reliability evaluation method based on applications and topological structure
Autorzy:
Huang, N.
Hou, D.
Chen, Y.
Kang, R.
Powiązania:
https://bibliotekanauki.pl/articles/301366.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
aplikacja
model Markowa
sieć
niezawodność
application
Markov model
network
reliability
Opis:
Aplikacje odgrywają ważną rolę w ocenie niezawodności sieci komunikacyjnych. Innymi słowy, niezawodność sieci może być całkowicie różna dla różnych aplikacji tej samej sieci. Niestety, istniejące metody oceny niezawodności, w większości oparte na teorii grafów, poświęcają niewiele lub nie poświęcają wcale uwagi aplikacjom. W niniejszym artykule przedstawiono koncepcję niezawodności aplikacji sieciowych oraz opartą na modelu Markowa metodę analizy proponowanej miary niezawodności aplikacji sieciowych. Ponadto, na podstawie niezawodności poszczególnych aplikacji, zaproponowano metodę oceny ogólnej niezawodności sieci, która łączy efekty różnych aplikacji działających w danej sieci. Zaproponowaną koncepcję i metody omówiono na podstawie studium przypadku oraz badań eksperymentalnych.
Applications play an important role in the reliability evaluation of communication networks. In other words, the reliability of a network can be totally different when different applications are considered for the same network. However existing reliability evaluation methods, which are mostly based on the graph theory, give no or little consideration to applications. This paper proposes a concept of network application reliability and a Markov-based method for analyzing the proposed network application reliability measure. Furthermore, based on the reliability of each individual application, a method is proposed to evaluate the overall network reliability that incorporates effects of different applications running on the network. Both a case study and experiments are performed to illustrate the proposed concept and methods.
Źródło:
Eksploatacja i Niezawodność; 2011, 3; 77-83
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neural network based identification of hysteresis in human meridian systems
Autorzy:
Tan, Y.
Dong, R.
Chen, H.
He, H.
Powiązania:
https://bibliotekanauki.pl/articles/330958.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
punkt akupunktury
histereza
sieć neuronowa
tradycyjna medycyna chińska
acupuncture point
hysteresis
identification
neural network
human meridian
traditional Chinese medicine
Opis:
Developing a model based digital human meridian system is one of the interesting ways of understanding and improving acupuncture treatment, safety analysis for acupuncture operation, doctor training, or treatment scheme evaluation. In accomplishing this task, how to construct a proper model to describe the behavior of human meridian systems is one of the very important issues. From experiments, it has been found that the hysteresis phenomenon occurs in the relations between stimulation input and the corresponding response of meridian systems. Therefore, the modeling of hysteresis in a human meridian system is an unavoidable task for the construction of model based digital human meridian systems. As hysteresis is a nonsmooth, nonlinear and dynamic system with a multi-valued mapping, the conventional identification method is difficult to be employed to model its behavior directly. In this paper, a neural network based identification method of hysteresis occurring in human meridian systems is presented. In this modeling scheme, an expanded input space is constructed to transform the multi-valued mapping of hysteresis into a one-to-one mapping. For this purpose, a modified hysteretic operator is proposed to handle the extremum-missing problem. Then, based on the constructed expanded input space with the modified hysteretic operator, the so-called Extreme Learning Machine (ELM) neural network is utilized to model hysteresis inherent in human meridian systems. As hysteresis in meridian system is a dynamic system, a dynamic ELM neural network is developed. In the proposed dynamic ELMneural network, the output state of each hidden neuron is fed back to its own input to describe the dynamic behavior of hysteresis. The training of the recurrent ELM neural network is based on the least-squares algorithm with QR decomposition.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 3; 685-694
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical Properties of a Bainitic Steel Producible by Hot Rolling
Autorzy:
Rana, R.
Chen, S.
Haldar, A.
Das, S.
Powiązania:
https://bibliotekanauki.pl/articles/352494.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
carbide-free bainite
retained austenite
hot rolling
mechanical properties
Opis:
A carbide-free bainitic microstructure is suitable for achieving a combination of ultra high strength and high ductility. In this work, a steel containing nominally 0.34C-2Mn-1.5Si-1Cr (wt.%) was produced via industrial hot rolling and laboratory heat treatments. The austenitization (900°C, 30 min.) and austempering (300-400°C, 3 h) treatments were done in salt bath furnaces. The austempering treatments were designed to approximately simulate the coiling step, following hot rolling and run-out-table cooling, when the bainitic transformation would take place and certain amount of austenite would be stabilized due to suppression of carbide precipitation. The microstructures and various mechanical properties (tensile properties, bendability, flangeability, and room and subzero temperature impact toughness) relevant for applications were characterized. It was found that the mechanical properties were highly dependent on the stability of the retained austenite, presence of martensite in the microstructure and the size of the microstructural constituents. The highest amount of retained austenite (~ 27 wt.%) was obtained in the sample austempered at 375°C but due to lower austenite stability and coarser overall microstructure, the sample exhibited lower tensile ductility, bendability, flangeability and impact toughness. The sample austempered at 400°C also showed poor properties due to the presence of initial martensite and coarse microstructure. The best combination of mechanical properties was achieved for the samples austempered at 325-350°C with a lower amount of retained austenite but with the highest mechanical stability.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 4; 2331-2338
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Risk assessment for industrial control systems quantifying availability using mean failure cost (MFC)
Autorzy:
Chen, Q.
Abercrombie, R. K.
Sheldon, F. T.
Powiązania:
https://bibliotekanauki.pl/articles/91644.pdf
Data publikacji:
2015
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Tematy:
Industrial Control Systems
ICS
SCADA systems
industry
data acquisition
supervisory control
IT network
mean failure cost
MFC
security
risk assessment
systemy automatyki przemysłowej
systemy SCADA
przemysł
pozyskiwanie danych
sprawowanie nadzoru
sieć IT
bezpieczeństwo
ocena ryzyka
Opis:
Industrial Control Systems (ICS) are commonly used in industries such as oil and natural gas, transportation, electric, water and wastewater, chemical, pharmaceutical, pulp and paper, food and beverage, as well as discrete manufacturing (e.g., automotive, aerospace, and durable goods.) SCADA systems are generally used to control dispersed assets using centralized data acquisition and supervisory control. Originally, ICS implementations were susceptible primarily to local threats because most of their components were located in physically secure areas (i.e., ICS components were not connected to IT networks or systems). The trend toward integrating ICS systems with IT networks (e.g., efficiency and the Internet of Things) provides significantly less isolation for ICS from the outside world thus creating greater risk due to external threats. Albeit, the availability of ICS/SCADA systems is critical to assuring safety, security and profitability. Such systems form the backbone of our national cyber-physical infrastructure. Herein, we extend the concept of mean failure cost (MFC) to address quantifying availability to harmonize well with ICS security risk assessment. This new measure is based on the classic formulation of Availability combined with Mean Failure Cost (MFC). The metric offers a computational basis to estimate the availability of a system in terms of the loss that each stakeholder stands to sustain as a result of security violations or breakdowns (e.g., deliberate malicious failures).
Źródło:
Journal of Artificial Intelligence and Soft Computing Research; 2015, 5, 3; 205-220
2083-2567
2449-6499
Pojawia się w:
Journal of Artificial Intelligence and Soft Computing Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mass transfer process of leaching weathered crust elution-deposited rare earth ore with magnesium salts
Autorzy:
Chen, Z.
Zhang, Z.
He, Z.
Chi, R.
Powiązania:
https://bibliotekanauki.pl/articles/110343.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mass transfer
magnesium salts
theory plate
weathered crust elution-deposited rare earth ore
Opis:
In order to optimize the leaching process of weathered crust elution-deposited rare earth ore with magnesium salts, the influence of different flow rate, concentration of magnesium ions, initial pH of magnesium salts solution and experimental temperature on the mass transfer process of rare earth and aluminum was investigated in the case of using magnesium salts as leaching agent. The relationship between the flow rate μ and the HETP (Height Equivalent of Theoretical Plate) is in accordance with the Van Deemter equation when magnesium salts were used as leaching agent. The optimum condition for rare earth and aluminum were 0.4 cm3/min of flow rate and 0.2 mol/dm3 of magnesium ion concentration of magnesium sulfate, magnesium chloride and magnesium nitrate respectively. Under this condition the mass transfer efficiency of rare earth and aluminum with three kinds of magnesium salts follow the order of Mg(NO3)2>Mg(Cl)2>MgSO4. High temperature contributes to improving the mass transfer efficiency of rare earth and aluminum. Magnesium nitrate as the leaching agent can get the highest leaching mass transfer efficiency of rare earth and magnesium sulfate as the leaching agent can make the impurity leaching and mass transfer efficiency of Al is the lowest.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 1004-1013
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dyeing Properties and Colour Characteristics of a Novel Fluorescent Dye Applied to Acrylic Fabric
Właściwości barwienia i charakterystyka kolorystyczna nowego barwnika fluorescencyjnego zastosowanego do barwienia akrylowych materiałów włókienniczych
Autorzy:
Liu, L.
Qin, C.
Tang, R. C.
Chen, G.
Powiązania:
https://bibliotekanauki.pl/articles/233699.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
hemicyanine dye
cationic fluorescent dye
acrylic fibre
dyeing
adsorption
barwnik hemicyjaniny
kationowy barwnik fluorescencyjny
włókno akrylowe
farbowanie
adsorpcja
Opis:
In this paper, hemicyanine fluorescent dye, namely, trans-4-[p-(N,N-diethylamino) -styryl]-N-methyl pyridinium bromide (DEASPBr), was synthesised and applied to the dyeing of acrylic fabric using the traditional cationic dyeing procedure. The absorption spectra of the novel dye were studied under various pHs, and the dyeing properties, fluorescent reflectance, and colorimetric properties were also explored. The results showed that the adsorption mechanism of DEASPBr on acrylic fibre was in good accordance with the Langmuir type, and the dye had an obvious fluorescent effect. In addition, according to the EN-471 standard, the dye could meet the requirements of the fluorescent orange dye for high visibility warning clothing in terms of chromaticity co-ordinates and luminance factors when its concentration was limited in the appropriate range.
W pracy przeprowadzono syntezę barwnika fluorescencyjnego bromku trans-4-[p-(N,Ndietyloamino)-styryl]-N-metyl pyrydinium (DEASPBr) oraz zastosowano go do barwienia dzianin akrylowych klasyczną metodą barwienia kationowego. Spektra absorpcji nowego barwnika były badane przy różnych wartościach pH, a następnie badano właściwości wybarwionych dzianin, takie jak fluorescencyjny współczynnik odbicia i właściwości kolorymetryczne. Badania wykazały, że mechanizm absorpcji barwnika do włókien akrylowych był w dobrej zgodności z modelem Langmuira i dawał oczywisty efekt fluorescencyjny. Zgodnie z normą EN-471 barwnik daje fluorescencyjny efekt barwnika pomarańczowego o dobrej widzialności, mogącego mieć zastosowanie w odzieży ostrzegawczej.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 4 (100); 144-147
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and simulation of an air conditioning project in a hospital based on computational fluid dynamics
Plan i symulacja projektu klimatyzacji w szpitalu, na podstawie obliczeniowej mechaniki płynów
Autorzy:
Ding, X. R.
Guo, Y. Y.
Chen, Y. Y.
Powiązania:
https://bibliotekanauki.pl/articles/230580.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
szpital
sala operacyjna
klimatyzacja
mechanika płynów
CFD
symulacja numeryczna
model turbulencji
projekt
hospital
operating room
air conditioning
fluid mechanics
numerical simulation
turbulence model
design
Opis:
This study aims to design a novel air cleaning facility which conforms to the current situation in China, and moreover can satisfy our demand on air purification under the condition of poor air quality, as well as discuss the development means of a prototype product. Air conditions in the operating room of a hospital were measured as the research subject of this study. First, a suitable turbulence model and boundary conditions were selected and computational fluid dynamics (CFD) software was used to simulate indoor air distribution. The analysis and comparison of the simulation results suggested that increasing the area of air supply outlets and the number of return air inlets would not only increase the area of unidirectional flow region in main flow region, but also avoid an indoor vortex and turbulivity of the operating area. Based on the summary of heat and humidity management methods, the system operation mode and relevant parameter technologies as well as the characteristics of the thermal-humidity load of the operating room were analyzed and compiled. According to the load value and parameters of indoor design obtained after our calculations, the airflow distribution of purifying the air-conditioning system in a clean operating room was designed and checked. The research results suggested that the application of a secondary return air system in the summer could reduce energy consumption and be consistent with the concept of primary humidity control. This study analyzed the feasibility and energy conservation properties of cleaning air-conditioning technology in operating rooms, proposed some solutions to the problem, and performed a feasible simulation, which provides a reference for practical engineering.
Przedmiotem tego badania była czysta sala operacyjna. Zastosowano technologię czystej klimatyzacji. Obciążenie chłodnicze czystej klimatyzacji w okresie letnim zostało obliczone przy użyciu praktycznej metody obciążenia chłodniczego klimatyzacji oraz oprogramowania służącego do obliczania zużycia energii. Wyniki obliczeń zostały porównane i przeanalizowane. Model rozprowadzania powietrza był symulowany za pomocą Airpak 3.0, a symulowane wyniki zostały przeanalizowane.
Źródło:
Archives of Civil Engineering; 2017, 63, 2; 23-38
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
AlGaAs to GaAs Energy Transfer Mechanisms in AlGaAs/GaAs Structures
Autorzy:
Karpińska, K.
Godlewski, M.
Żytkiewicz, Z. R.
Chen, W. M.
Weber, E. R.
Powiązania:
https://bibliotekanauki.pl/articles/1921617.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
76.70.Hb
78.55.Cr
Opis:
The results of photoluminescence and optically detected cyclotron resonance experiments are presented for thick AlGaAs epilayers grown by liquid phase electroepitaxy method on GaAs:Cr substrate. These results indicate an efficient energy transfer from excited AlGaAs to GaAs.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 713-716
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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