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Wyszukujesz frazę "Zhang, He" wg kryterium: Autor


Tytuł:
A fault diagnosis method for substation grounding grid based on the square-wave frequency domain model
Autorzy:
Zhang, P.-H.
He, J.-J.
Zhang, D.-D.
Wu, L.-M.
Powiązania:
https://bibliotekanauki.pl/articles/221635.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
square-wave
frequency characteristics
grounding grid
fault diagnosis
Opis:
Current methods of fault diagnosis for the grounding grid using DC or AC are limited in accuracy and cannot be used to identify the locations of the faults. In this study, a new method of fault diagnosis for substation grounding grids is proposed using a square-wave. A frequency model of the grounding system is constructed by analyzing the frequency characteristics of the soil and the grounding conductors into which two different frequency square-wave sources are injected. By analyzing and comparing the corresponding information of the surface potentials of the output signals, the faults of the grounding grid can be diagnosed and located. Our method is verified by software simulation, scale model experiments and field experiments.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 63-71
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mechanism reliability analysis method considering environmental influence and failure modes’ correlation : a case study of rifle automaton
Autorzy:
Fang, Yi-chuan
Wang, Yong-juan
Sha, Jin-long
Gu, Tong-guang
Zhang, He
Powiązania:
https://bibliotekanauki.pl/articles/24200826.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
mechanism reliability
environmental influence
failure modes’ correlation
copula function
Kaplan-Meier estimation
rifle automaton
Opis:
In order to overcome the challenge of quantifying the influence of environmental conditions and the coexistence of multiple failure modes involved in mechanism reliability modelling under different environments. In this paper, we propose a method for the analysis of mechanism reliability that takes into account the influence of environmental factors and failure modes’ correlation, quantifies the influence of environmental factors as the random distribution and degradation path of parameters, and derives the Copula description of failure mode correlation from the historical data of environmental experiments. On the basis of the discrete mechanism dynamics model, the output parameters of the characteristic points are calculated, and the failure rate of each failure mode is calculated based on the failure criterion and the performance margin theory. Additionally, the dynamic change pattern of the mechanism reliability is compared with the Kaplan-Meier estimation of the corresponding environmental test history data to assess the validity of the calculation results. The reliability modelling problem of a motion mechanism of an automatic rifle automaton in a high and low temperature environment is applied to the method, and the reliability calculation results are close to those of Kaplan-Meier estimation of the test history data, and all are within the upper and lower bounds given by the reliability boundary theory, demonstrating the method's validity.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 2; art. no. 166145
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Novel Approach To Diagnosis Of Analog Circuit Incipient Faults Based On KECA And OAO LSSVM
Autorzy:
Zhang, C.
He, Y.
Zuo, L.
Wang, J.
He, W.
Powiązania:
https://bibliotekanauki.pl/articles/221378.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analog circuits
incipient fault diagnosis
wavelet transform
kernel entropy component analysis
least squares support vector machine
Opis:
Correct incipient identification of an analog circuit fault is conducive to the health of the analog circuit, yet very difficult. In this paper, a novel approach to analog circuit incipient fault identification is presented. Time responses are acquired by sampling outputs of the circuits under test, and then the responses are decomposed by the wavelet transform in order to generate energy features. Afterwards, lower-dimensional features are produced through the kernel entropy component analysis as samples for training and testing a one-against-one least squares support vector machine. Simulations of the incipient fault diagnosis for a Sallen-Key band-pass filter and a two-stage four-op-amp bi-quad low-pass filter demonstrate the diagnosing procedure of the proposed approach, and also reveal that the proposed approach has higher diagnosis accuracy than the referenced methods.
Źródło:
Metrology and Measurement Systems; 2015, 22, 2; 251-262
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An alternating current calibration method for Helmholtz coil constant based on orthogonal calculation principle
Autorzy:
Zhang, Kuankuan
Cao, Mingxing
He, Jian
Gong, Wenjie
Huang, Yunhua
Powiązania:
https://bibliotekanauki.pl/articles/27311758.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Helmholtz coils constant
alternating current method
induction voltage
orthogonal calculations
Opis:
The Helmholtz coil constant (ℎ) is a crucial standard in magnetic moment measurement devices for permanent magnet materials. To overcome the problem of low accuracy of the direct-current (DC) calibration method, this study used a constant sinusoidal current in the Helmholtz coil and measured the induced voltage of the detection coil with known coil turns and coil area. Subsequently, the ℎ was calculated. The noise signal deduction rate in the induction voltage of the detection coil was greater than 99%, its influence on the induction voltage is less than 0.005%, and the repeatability of the calibration results is 0.003% (1). The results reveal that the alternating current (AC) method and orthogonal calculation (OC) can accurately measure the valid values of the voltage signal under the influence of the spatial stray field during the calibration of ℎ.
Źródło:
Metrology and Measurement Systems; 2023, 30, 3; 549--561
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An integrated treatment technology for ground fissures of shallow coal seam mining in the mountainous area of southwestern China: a typical case study
Zintegrowana technologia zapobiegania pęknięciom gruntu w procesie wydobywania płytkich pokładów węgla w górzystym obszarze południowo-zachodnich Chin: typowe studium przypadku
Autorzy:
Zhu, H.
He, F.
Zhang, S.
Yang, Z.
Powiązania:
https://bibliotekanauki.pl/articles/215969.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
wydobywanie węgla
płytki pokład węgla
pęknięcia gruntu
zapadlisko górnicze
zintegrowana technologia zapobiegania
ochrona środowiska
shallow coal seam mining
ground fissures
surface sinkhole
integrated treatment technology
environmental protection
Opis:
This article is the result of treatments on ground fissures for environmental protection and scientific shallow coal seam mining. In the southwestern mining area of China, the traditional longwall mining method has caused a large area of surface sinkhole, ground fissures, vegetation deterioration and disorderly coal gangue. To solve these problems, an integrated treatment technology that includes ground fissure treatment technology and underground backfilled technology was proposed as a solution. The technical principle and technical process were explained in detail; the ground fissure treatment technology involves a “three-step treatment method”, and the underground backfilled technology adopted a strip mining method with backfilling technology. The compression mechanical behavior of backfilled material, including coal gangue, fly ash and ordinary Portland cement, was studied; the mixed ratio of 1:0.3:0.18 was selected. In addition, the vertical stress, vertical displacement and plastic zone of the coal pillar were determined by FLAC3D numerical simulation, and a rational mining scheme of “11 m mining width, 2 m coal pillar width” was determined to be appropriate because of the lower vertical stress, smaller vertical displacement and better supporting capacity of the coal pillar. The monitoring results of ground sinkhole indicated that the maximal ground sinkhole deformation was 17.3 cm, and the deformation showed few changes after this technology was implemented. The treatment capacity of coal gangue and fly ash reached 821.150 t per year, and the vegetation survival rate of the ground fissure treatment area reached 85%. This integrated treatment technology could effectively control ground fissures and surface sinkhole as well as protect the environment.
Artykuł jest opisem zapobiegania pęknięciom gruntu w celu ochrony środowiska, jak również naukowego podejścia do wydobywania płytko zalegających pokładów węgla. W południowo-zachodniej części górniczej Chin tradycyjna, ścianowa metoda wydobywania węgla, powodowała duży obszar powierzchniowego zapadliska, pęknięcia gruntu, pogorszenie stanu wegetacji roślin. W celu rozwiązania tych problemów zaproponowano zintegrowaną technologię zapobiegania, która obejmuje technologię zapobiegania pęknięciom gruntu i podziemną technologię podsadzki. Zasada i proces techniczny zostały szczegółowo opisane; technologia zapobiegania pęknięciom gruntu obejmuje „trójstopniową metodę zabiegu”, a technologia podsadzki zaadoptowała metodę wydobywania węgla pasami. Badano ściśliwość podsadzki, w tym odpadów węglowych, popiołu lotnego i zwykłego cementu portlandzkiego; wybrano mieszaninę o stosunku 1: 0,3: 0,18. Ponadto pionowe naprężenie, pionowe przemieszczenie i strefa plastyczności filaru węglowego zostały określone za pomocą symulacji numerycznej FLAC 3D. Racjonalny schemat wydobycia „szerokość wydobycia 11 m, szerokość filaru węglowego 2 m” był odpowiedni ze względu na niższą wartość naprężenia pionowego, mniejsze pionowe przemieszczenie i lepszą nośność filaru węglowego. Wyniki monitoringu pęknięć gruntu wskazują, że maksymalna deformacja gruntu wynosiła 17,3 cm i wykazała kilka zmian po wdrożeniu tej technologii. Ilość zagospodarowanych odpadów węglowych i popiołu lotnego wynosiła 821 150 Mg na rok, a wskaźnik przeżycia roślinności w obszarze zapobiegania pęknięciom gruntu osiągnął poziom 85%. Ta zintegrowana technologia zapobiegania może skutecznie kontrolować pęknięcia gruntu i deformację powierzchni, a także chronić środowisko.
Źródło:
Gospodarka Surowcami Mineralnymi; 2018, 34, 1; 119-138
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An on-site calibration system for electronic instrument transformers based on LabVIEW
Autorzy:
Zhang, M.
Li, K.
Wang, J.
He, S.
Powiązania:
https://bibliotekanauki.pl/articles/221656.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
calibration system
electronic instrument transformers
data acquisition
data synchronization
LabVIEW
Opis:
Electronic voltage transformers (EVT) and electronic current transformers (ECT) are important instruments in a digital substation. For simple, rapid and convenient development, the paper proposed an on-site calibration system for electronic instrument transformers based on LabVIEW. In the system, analog signal sampling precision and dynamic range are guaranteed by the Agilent 3458A digital multimeter, and data synchronization is also achieved based on a self-developed PCI synchronization card. To improve the measurement accuracy, an error correction algorithm based on the Hanning window interpolation FFT has good suppression of frequency fluctuation and inter-harmonics interference. The human-computer interface and analysis algorithm are designed based on LabVIEW, and the adaptive communication technology is designed based on IEC61850 9-1/2. The calibration system can take into account pairs of digital output and analog output of the electronic voltage/current transformer calibration. The results of system tests show that the calibration system can meet the requirements of 0.2 class calibration accuracy, and the actual type test and on-site calibration also show that the system is easy to operate with convenience and satisfactory stability.
Źródło:
Metrology and Measurement Systems; 2014, 21, 2; 257-270
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antibiotics in WWTP discharge into the Chaobai River, Beijing
Autorzy:
Zhang, C.
Wang, L.
Gao, X.
He, X.
Powiązania:
https://bibliotekanauki.pl/articles/204951.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
antibiotics
PPCPs
pharmaceuticals and personal care products
WWTP
wastewater treatment plant
BAF
biological aerated filter
advanced treatment
Opis:
22 representative antibiotics, including 8 quinolones (QNs), 9 sulfonamides (SAs), and 5 macrolides (MCs) were selected to investigate their occurrence and removal efficiencies in a Wastewater Treatment Plant (WWTP) and their distribution in the receiving water of the Chaobai River in Beijing, China. Water quality monitoring was performed in an integrated way at different selected points in the WWTP to explore the potential mechanism of antibiotics removal during wastewater treatment. Water quality of the Chaobai River wa s also analyzed to examine environmental distribution in a river ecosystem. The results showed that within all the 22 compounds examined, 10 antibiotics were quantifi ed in wastewater influent, 10 in effluent, and 7 in river. Sulfadiazine (SDZ, 396 ng/L) and Sulfamethazine (SMZ, 382 ng/L) were the dominating antibiotics in the influent. Both the conventional treatment and advanced Biological Aerated Filter (BAF) system was important for the removal of antibiotics from the wastewater. And the concentrations of selected antibiotics were ranged from 0–41.8 ng/L in the effluent-receiving river. Despite the fact that the concentrations were reduced more than 50% compared to effluent concentrations, WWTP discharge was still regarded as a dominant point-source input of antibiotics into the Chaobai River.
Źródło:
Archives of Environmental Protection; 2016, 42, 4; 48-57
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
BERBERINE INDUCES AUTOPHAGY, APOPTOSIS AND MODULATES MIR-155 IN HEAD AND NECK SQUAMOUS CARCINOMA CELLS.
Autorzy:
Xue, Kai
Zhang, Binbin
He, Jingchuan
Powiązania:
https://bibliotekanauki.pl/articles/895286.pdf
Data publikacji:
2020-06-29
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
apoptosis
miR-155
Autophagy
berberine
Head and Neck cancer cells
Opis:
Berberine (BBR) an active natural plant alkaloid extracted from Coptidis rhizoma, displays potent anticancer activity over a variety of cancer cell lines. The cytotoxic activity of BBR in cancer cells is attributed to persuade, programmed cell death characterized by the release of cytochrome c, accompanied by activation of caspase-3 and caspase-9. In the present study, we evaluated BBR significantly reduces the cell viability and clonogenic property of head and neck squamous carcinoma (HNSC) cells. Our results revealed that BBR simultaneously induces apoptosis and autophagy in HNSC cells. Mechanistically, BBR induces autophagy in HNSC cells which were confirmed by acridine orange (AO) staining by visualization of prominent orange red color acidic autophagosomes in the cytoplasm. However, immunoblotting shows the steady conversion of MAP-LC-3I to LC-3II with concomitant degradation of autophagy substrate protein SQSTM1/p62. Annexin V FITC staining analysis by flow cytometry revealed a significant induction of apoptosis at higher doses of BBR. Furthermore, the immunoblotting analysis revealed a prominent cleavage of proapoptotic proteins procaspase-3 and PARP1 at higher doses of BBR. Additionally, we found significant upregulation and downregulation of tumor suppressor microRNA-155 (miR-155) and oncogenic miR-21 respectively, when HNSC cells were exposed to higher doses of BBR. In conclusion, these results demonstrate that BBR exhibits a significant anti-proliferative effect with the simultaneous induction of autophagy and apoptosis and modulates miRNA expression in HNSC cells.
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2020, 77, 3; 485-494
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of monochlorobenzene contamination in soils using geostatistical interpolation and 3D visualization for agrochemical industrial sites in southeast China
Autorzy:
Ren, L.
Lu, H.
He, L.
Zhang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/204614.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
soil pollution
monochlorobenzene
POPs
persistent organic pollutants
geostatistical interpolation
3D visualization
Opis:
Persistent organic pollutants (POPs) originating from agrochemical industries have become an urgent environmental problem worldwide. Ordinary kriging, as an optimal geostatistical interpolation technique, has been proved to be sufficiently robust for estimating values with finite sampled data in most of the cases. In this study, ordinary kriging interpolation integrate with 3D visualization methods is applied to characterize the monochlorobenzene contaminated soil for an agrochemical industrial site located in Jiangsu province. Based on 944 soil samples collected by Geoprobe 540MT and monitored by SGS environmental monitoring services, 3D visualization in terms of the spatial distribution of pollutants in potentially contaminated soil, the extent and severity of the pollution levels in different layers, high concentration levels and isolines of monochlorobenzene concentrations in this area are provided. From the obtained results, more information taking into account the spatial heterogeneity of soil area will be helpful for decision makers to develop and implement the soil remediation strategy in the future.
Źródło:
Archives of Environmental Protection; 2016, 42, 3; 17-24
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Climatic signals in tree rings of Juniperus turkestanica in the Gulcha River Basin (Kyrgyzstan), reveals the recent wetting trend of high Asia
Autorzy:
Chen, F.
He, Q.
Bakytbek, E.
Yu, S.-L.
Zhang, R.-B.
Powiązania:
https://bibliotekanauki.pl/articles/41289.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Opis:
Drought variability of Kyrgyzstan is an important component of climate change of high Asia. Long-term information about the history of drought is, however, limited because the instrumental records are short. Here, we developed three chronologies for juniper trees (Juniperus turkestanica) under different microsite conditions in the Gulcha River Basin, Kyrgyzstan. The three chronologies (GUL, GUR and GUD) were compared with climate data which covered the study area. Growth of the GUL site correlates positively with May–June precipitation of the current growing season and September precipitation of the previous year, but negatively with temperatures of prior July, current May and July. Growth of the GUR site correlates positively with precipitation of current May and September, and negatively with temperature of current June and July. Ring width at GUD site is negatively correlated with temperature of the current May and July, and positively correlated with precipitation of prior December and current September. Response analysis shows that water availability is the main factor limiting the radial growth of juniper trees at the GUL and GUD sites. Based on the relationships derived from climate response analyses, the potential of tree-ring chronologies from this species to provide drought reconstructions in the Gulcha River Basin has been established. The GUL chronology and other moisture sensitive tree-ring series from high Asia capture the recent wetting trend. The records contribute to a growing tree-ring network for high Asia, including sites in China, Kyrgyzstan, Pakistan and Tajikistan.
Źródło:
Dendrobiology; 2015, 74
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of float-sink and progressive release flotation of ground products of coal middlings
Autorzy:
Xie, W.
He, Y.
Luo, C.
Zhang, X.
Li, H.
Yu, J.
Wang, H.
Shi, F.
Powiązania:
https://bibliotekanauki.pl/articles/109500.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
coal middlings
float-sink
progressive release flotation
XPS
EDX
Opis:
An additional recovery of coking coal middlings can be utilized for increasing of the concentrate yield of coking coal. A combined flow sheet of comminution and flotation can realize this target. To investigate the effect of grinding process on further flotation of ground products, progressive release flotation tests were used to compare with the float-sink tests, which were regarded as a criterion. Coal middlings were ground by wet-milling with iron balls to <0.5 mm. Curves of ash vs. cumulative yields of sized products indicated that the concentrate yield of coal separated by progressive release flotation was lower than that of coal benefited by the float-sink test, with the same ash for four size fractions (0.5-0.25 mm, 0.25-0.125 mm, 0.125-0.074 mm and <0.074 mm). Distributions of elements conducted by energy disperse spectroscopy (EDX) showed that associated kaolinite was liberated and exposed on the surface. It led to the shift of local surface property from hydrophobicity to hydrophilicity. Meanwhile, analyses of chemical property performed by an X-Ray photoelectron spectrometer (XPS) depicted that the hydrophilic mineral FeOOH, which generated in the grinding process, was adsorbed on the coal surface. Flotation of the ground products were worsened due to the increase of hydrophilicity of the coal surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 2; 675-684
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comprehensive Analysis of Metal Deformation Law Based on Numerical Simulation of Cold Rolling Process
Autorzy:
Yan, Zhu-Wen
Wang, Bao-Sheng
Bu, He-Nan
Li, Hao
Hong, Lei
Zhang, Dian-Hua
Powiązania:
https://bibliotekanauki.pl/articles/2106570.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
3D elastic-plastic FEM
work roll deflection
lateral thickness
flatness regulation effect
rolling pressure
Opis:
Through taking the cold rolling process as the research object, the three-dimensional finite element model of the strip rolling process is established by using ANSYS/LS-DYNA software. The actual rolling product data has strong consistency with the finite element simulation results. The rolling process is dynamically simulated, and the distribution curves of important rolling parameters such as equivalent stress, control efficiency coefficient, transverse rolling pressure, lateral thickness and work roll deflection is obtained. Based on summarizing the influence of rolling parameters on rolling deformation, the research results of this paper can play an important role in the actual rolling process control. The research results have certain guiding significance for the development and optimization of the rolling control system.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 2; 623--635
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Depth-resolved measurement of the compression displacement fields on the front and rear surfaces of an epoxy sample
Autorzy:
Zhang, W.
Dong, B.
He, Z.
Xie, S.
Zhou, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174399.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
depth-resolved measurement
compression displacement field
wavenumber-scanning interferometry
epoxy
Opis:
Compression is one of the typical parameters measured in material mechanics. In this research, the compression displacement fields on the front and rear surfaces of an epoxy sample are measured by using a tilt depth-resolved wavenumber-scanning Michelson interferometer. The light source is a distributed feedback laser diode, the wavenumber of which can be modulated to about 1.017 × 104 m–1 by the temperature without mode hopping. A random-sampling Fourier transform is designed to evaluate the phase differences before and after the applied loads. Experimental results show that the depth-resolved measurement of the compression displacement field is of high accuracy. It can be used to analyze force propagation inside resin-based composites.
Źródło:
Optica Applicata; 2018, 48, 2; 311-323
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and test of a new high-current electronic current transformer with a Rogowski coil
Autorzy:
Zhang, M.
Li, K.
He, S.
Wang, J.
Powiązania:
https://bibliotekanauki.pl/articles/221051.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Rogowski coil
high-current
electronic current transformers
electrical measurements
Opis:
This paper describes the design and test of a new high-current electronic current transformer based on a Rogowski coil. For better performances, electronic current transformers are used to replace conventional electro-magnetic inductive current transformers based on ferromagnetic cores and windings to measure high-current on the high voltage distribution grids. The design of a new high-current electronic current transformer is described in this paper. The principal schemes of the prototype and partial evaluation results are presented. Through relative tests it is known that the prototype has a wide dynamic range and frequency band, and it can allow high accuracy measurements.
Źródło:
Metrology and Measurement Systems; 2014, 21, 1; 121-132
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diatomaceous ooze in a sedimentary core from Mariana Trench: implications for paleoceanography
Autorzy:
Zhang, Jinpeng
Witkowski, Andrzej
Tomczak, Michał
Mccartney, Kevin
He, Gaowen
Zgłobicka, Izabela
Powiązania:
https://bibliotekanauki.pl/articles/139209.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
diatomaceous ooze
diatom
Ethmodiscus rex
Mariana Trench
challenger deep
muł okrzemkowy
okrzemki
Rów Mariański
Głębia Challengera
Opis:
Diatomaceous ooze sampled from near the Mariana Trench sediment surface by gravity corer (Core JL7KGC05) revealed a high sedimentary abundance of Ethmodiscus rex (Rattray, 1890) Wiseman and Hendey, 1953 fragments and tropical open ocean planktonic diatom taxa including Azpeitia nodulifera (Schmidt, 1878) Fryxell and Watkins in Fryxell, Sims and Watkins, 1986 and Alveus marinus (Grunow, 1880) Kaczmarska and Fryxell, 1996. Subsurficial sediments from the ooze are assigned a Marine Isotope Stage 2 age, approximately at the Last Glacial Maximum. The occurrence of Ethmodiscus ooze suggests massive late Pleistocene blooms in the Northwestern Pacific Ocean and provides a plausible link to paleoceanographic and paleoclimatic changes related to Antarctic Intermediate Water mass, which carried a high dissolved silica content as silicon leakage that reduced dissolution rate of diatom frustules. Northward flow of Antarctic Intermediate Water was probably related to surface current migration and southward shift of the Northwest Pacific Gyre to form oligotrophic conditions that triggered Ethmodiscus rex blooms under unusual nutrient recycling conditions within the ocean system. This bloom hypothesis may help explain differential silica dissolution during the last glacial stage.
Źródło:
Acta Geologica Polonica; 2019, 69, 4; 627-643
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł

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