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Wyszukujesz frazę "Han, X." wg kryterium: Autor


Tytuł:
Spatial distribution, environmental risk and source of heavy metals in street dust from an industrial city in semi-arid area of China
Autorzy:
Han, X.
Lu, X.
Tematy:
heavy metals
spatial distribution
source
risk assessment
industrial city
dust
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/204586.pdf  Link otwiera się w nowym oknie
Opis:
Environmental risks associated with Co, Cr, Cu, Mn, Ni, Pb, V and Zn in street dust collected from Baotou, a medium-sized industrial city in a semi-arid area of northwest China, were assessed by using enrichment factor and the potential ecological index. Their spatial distributions and sources in the dust were analyzed on the basis of geostatistical methods and multivariate statistical analysis, respectively. The results indicate that street dust in Baotou has elevated heavy metal concentrations, especially of Co, Cr, Cu, Pb and Zn. Co in the dust was significantly enriched. Cr and Pb were from moderate to significant enrichment. Cu and Zn were from minimal to moderate enrichment, whereas Mn, Ni and V in the dust were from deficient to minimal enrichment. The ecological risk levels of Co and Pb in the dust were moderate to considerable and low to moderate, respectively, whereas those of other heavy metals studied in the dust presented low ecological risk. Different distribution patterns were found among the analyzed heavy metals. Three main sources of these heavy metals were identified. Cr, Mn, Ni and V originated from nature and industrial activities. Cu, Pb and Zn derived mainly from traffic sources, and Co was mainly from construction sources.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the optimization and performance of TDMA allocation algorithm in ships’ ad hoc networks
Autorzy:
Han, X.
Li, Y.
Liu, G.
Tematy:
timeslot allocation algorithm
ships
ad hoc network
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Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:
https://bibliotekanauki.pl/articles/259367.pdf  Link otwiera się w nowym oknie
Opis:
This paper analyzes the requirements of the information transmission network of ship integrated condition monitoring system, and proposes a design scheme of ship condition monitoring system based on wireless ad hoc network. The wireless ad hoc network protocol was designed, its networking process was analyzed in detail, and the network transmission performance of the monitoring system was tested. The results proved the feasibility of the system. The above solution can be used for the transmission of ship state information that satisfies the requirements of wireless transmission, and has important theoretical and practical significance. The slot allocation algorithm has been receiving extensive attention as an important part of the TDMA system research. This paper analyzes the summarization and summarization of TDMA time slot assignment algorithms from several aspects such as slot synchronization, existing slot allocation algorithm, and slot assignment model, laying an important foundation for researchers to do further research. In the TDMA system, time is divided into non-overlapping time frames, and the time frames are divided into non-overlapping time slots. Each node in the network performs corresponding operations in each time slot.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Ships Safety Control System
Autorzy:
Han, X. J.
Meng, X. Y.
Wang, Z. W.
Tematy:
Safety of Navigation
ships safety
Control System
Ships Safety Control System
Ship Accidents
Human Factor
Control Strategy
Accident Precaution
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Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:
https://bibliotekanauki.pl/articles/117442.pdf  Link otwiera się w nowym oknie
Opis:
The proportion of main reasons of ships accidents to the whole reasons is discussed in the paper. Among these reasons, human factors are in the majority. So a method to prevent wrong orders sent by a navigator is laid emphasis on. On the basis of this, a ships safety control system is studied. The construction and control principle of the ships safety control system, as well as control strategy, implementation method and key technology are elaborated in the paper.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Permeability of P and K-nutrient through polystyrene membrane from aqueous solutions of urea + KH2PO4
Autorzy:
Deng, X.
Liu, K.
Han, X.
Hu, X.
Zheng, S.
Tematy:
Permeability
polymer membrane
aqueous fertilizer solution
polymer-coated fertilizer
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Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:
https://bibliotekanauki.pl/articles/777858.pdf  Link otwiera się w nowym oknie
Opis:
With the polymer-coated fertilizer as background, the permeability of P- and K-nutrient through a representative polymer membrane-polystyrene membrane were investigated by measuring their permeability in the solutions of KH2 PO4 -water and urea-KH2 PO4 water at nominal temperature of 298 K using the Ussing chamber method. To analyze and interpret the variation of permeability with solute concentration, the solubility of permeate in polymer membrane were determined experimentally and the permeate diffusion coefficient were assessed by the measurements of density and apparent molar volume of the aqueous fertilizer solutions. An interesting “increase-decrease” trend for the permeability of both phosphorous (P)-nutrient, and potassium (K)-nutrient fertilizer with permeate concentration was observed, in which the increases in permeability at low concentrations of permeate could be attributed to the increase in solubility of KH2 PO4  in polymer while the decreases in permeability at high concentrations was due to the decrease in diffusion coefficient of permeate in polymer membrane. Finally, the release kinetics of these nutrients from a PS-coated urea-KH2 PO4  compound fertilizer granule was predicted using the Shaviv’s model along with the permeability data of P- and K-nutrient generated.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Power Density on Diffusion Length and Energy Gap of a-Si:H and nc-Si:H Thin Films Prepared by PECVD Technique
Autorzy:
Badran, R.
Al-Amodi, H.
Yaghmour, S.
Shaklan, S.
Bruggemann, R.
Han, X.
Xiong, S.
Tematy:
78.20.-e
78.20.Ci
73.61.Jc
78.30.Ly
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1419002.pdf  Link otwiera się w nowym oknie
Opis:
The increase in power density of 0.3, 0.5, 0.6, and 0.7 W $cm^{-2}$ for hydrogenated amorphous and nanocrystalline silicon (a-Si:H and nc-Si:H) thin film samples prepared by plasma enhanced chemical vapor deposition technique causes an increase in crystalline volume fraction when the silane concentration is fixed. This increase in crystalline volume fraction is correlated to the absorption coefficient and refractive index which are determined from ellipsometric measurements. The crystallinity of samples is studied by both Raman and X-ray diffraction techniques. A mild change in the optical energy gap around an average value of 1.8 eV is noticed due to the observed change in the degree of crystallinity of the samples when power density increases. Moreover, the ambipolar diffusion length measured by the steady-state photocarrier grating technique is found to change with the increase in power density. The values of some obtained optical parameters are compared to a standard crystalline sample.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selective flotation of siderite and quartz from a carbonate-containing refractory iron ore using a novel amino-acid-based collector
Autorzy:
Gu, X.
Zhu, Y.
Li, Y.
Han, Y.
Tematy:
flotation
quartz
hematite
siderite
refractory iron ores
molecular simulation
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/110222.pdf  Link otwiera się w nowym oknie
Opis:
A novel and highly-efficient amino-acid-based collector, α-ethylenediamine lauric acid (α-EDA-LA), was studied to selectively beneficiate carbonate-containing refractory hematite ores. Single mineral and synthetic mixture flotation tests were carried out to investigate its floating performance. Zeta potential, fourier transform infrared spectroscopy (FTIR) and Density Functional Theory-based molecular simulation were used to identify the adsorption mechanism. The flotation results showed that quartz could be collected effectively at pH 11.0-12.0 in the reverse flotation. For siderite, the recovery peaked at 83.4% at pH 8.0, where siderite presented different floatability from magnetite and hematite. Exploiting such difference, the separation of siderite could be achieved. Zeta-potential measurements showed that α-EDA-LA adsorption on the surfaces of siderite and quartz decreased the corresponding zeta potentials at pH of 8.0-10.0 and 8.0-12.0, respectively. This means the adsorption overcome the electrostatic repulsion between α-EDA-LA and the mineral surfaces. The molecular simulation indicated that no chemisorption took place between α-EDA-LA and quartz. FTIR analysis suggested that α-EDA-LA was adsorbed on quartz via hydrogen bonding. The adsorption of α-EDA-LA on siderite surface was dominated by chemisorption, while further enhanced by hydrogen bonding. This study filled the gap in the research on siderite flotation reagents and its adsorption mechanism.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of HFC-134a decomposition by combustion and its kinetic characteristics in a laboratory scale reactor
Autorzy:
Mi, T.
Han, J.
He, X.
Qin, L.
Tematy:
thermal decomposition
hydrochlorofluorocarbons
HFC
combustion
R134a
rozkład termiczny
hydrofluorokarbony
freony
spalanie
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Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:
https://bibliotekanauki.pl/articles/207909.pdf  Link otwiera się w nowym oknie
Opis:
Thermal decomposition of HFC-134a at 900–1000 K was investigated using a laboratory scale reactor. The experimental results indicate that the lower initial HFC-134a concentration and higher reaction temperature could enhance HFC-134a decomposition efficiency. Based on the results of measurements, it seems that the reaction order is around 1. Its activation energy (Ea) and the frequency factor (A) in the investigated temperature range are 300.5 kJ·mol–1 and 2.96×1014, respectively. The results demonstrate that 99.9% destruction efficiency could be achieved when HFC-134a/LPG is below 0.5 and the excess air ratio – above 0.6.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An active fault-tolerant control framework against actuator stuck failures under input saturations
Autorzy:
Qi, X.
Theilliol, D.
He, Y.
Han, J.
Tematy:
fault tolerant control
actuator stuck failure
actuator constraints
reference redesign
linear matrix inequality
sterowanie tolerujące uszkodzenia
projekt odniesienia
liniowa nierówność macierzowa
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Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:
https://bibliotekanauki.pl/articles/331084.pdf  Link otwiera się w nowym oknie
Opis:
In this paper, a control framework including active fault-tolerant control (FTC) and reference redesign is developed subject to actuator stuck failures under input saturations. FTC synthesis and reference redesign approaches are proposed to guarantee post-fault system safety and reference reachability. Then, these features are analyzed under both actuator stuck failures and constraints before fault-tolerant controller switches. As the main contribution, actuator stuck failures and constraints are unified so that they can be easily considered simultaneously. By means of transforming stuck failures into actuator constraints, the post-fault system can be regarded as an equivalent system with only asymmetrical actuator constraints. Thus, methods against actuator saturations can be used to guarantee regional stability and produce the stability region. Based on this region, stuck compensation is analyzed. Specifically, an unstable open-loop system is considered, which is more challenging. Furthermore, the method is extended to a set-point tracking problem where the reachability of the original reference can be evaluated. Then, a new optimal reference will be computed for the post-fault system if the original one is unreachable. Finally, simulation examples are shown to illustrate the theoretical results.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative study of fault-tolerant performance of a segmented rotor SRM and a conventional SRM
Autorzy:
Sun, X.
Xue, Z.
Han, S.
Chen, L.
Xu, X.
Yang, Z.
Tematy:
fault tolerance
segmented rotor SRM
phase failure
finite element method
dynamic performance
rotor segmentowy SRM
metoda elementów skończonych
wydajność dynamiczna
tolerancja błędu
awaria jednej fazy
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/200893.pdf  Link otwiera się w nowym oknie
Opis:
Due to the separation of magnetic field, electrical isolation and thermal isolation, motor drives possess a high fault-tolerance characteristic. In this paper, comparative study of mutual inductance between the proposed segmented rotor switched reluctance motor (SSRM) and the conventional switched reluctance motor (SRM) is carried out first, illustrating that the proposed SSRM has less mutual inductance between phases than the conventional SRM. In addition, if winding faults or power converter faults lead to phase failure, a comparative analysis on fault-tolerant performance under phase failure condition between the proposed SSRM and the conventional SRM is simulated in detail using the finite element method (FEM). Simulation results reveal that dynamic performance of the proposed SSRM, including output torque and phase current, is better than that of the conventional SRM. That is, the capacity of operating with the fault under phase failure condition in the proposed SSRM is superior to that in the conventional SRM.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soft-tissue preservation in the Lower Cambrian linguloid brachiopod from South China
Autorzy:
Zhang, Z
Han, J.
Zhang, X.
Liu, J.
Shu, D.
Tematy:
Lingulellotreta malongensis
Chengjiang Lagerstatte
soft tissue preservation
lophophore
brachiopod
linguloid brachiopod
China
Linguloidea
gastrointestinal tract
Cambrian
Lower Cambrian
paleontology
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Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:
https://bibliotekanauki.pl/articles/20001.pdf  Link otwiera się w nowym oknie
Opis:
The organization of the lophophore and the digestive system are recognized as two of the diagnostic characters in the definition of higher brachiopod taxa, and hence play a major role in their phylogenetic analysis, their structure, however, is very rarely fossilized. Here we describe and interpret specimens of the brachiopod Lingulellotreta malongensis, from the Lower Cambrian Chengjiang Lagerstätte (South China), one of the earliest known taxa of the Lingulellotretidae, in which lophophores and intact, U−shaped digestive tracts are extraordinarily well−preserved. The lophophore, with clearly preserved tentacles, corresponds to an early spirolophe developmental stage. The digestive tract consists of a mouth, esophagus, distended stomach, intestine and an anterior anus, and differs from that of the Chengjiang obolid Lingulella chengjiangensis by the presence of the dilated stomach and by the absence of a looped intestine as in Lingula. In addition, the relative sizes of the mantle and visceral cavities of Lingulellotreta malongensis also are described. These fossils demonstrate that by the Atdabanian brachiopods had already possessed advanced features, and suggest that a lophophore and a U−shaped intestine with an anterior anus are brachiopod plesiomorphies.
Dostawca treści:
Biblioteka Nauki
Artykuł

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