Autor: Xu, Z. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: An MST cluster analysis method under hesitant fuzzy environment
Autorzy:: Zhang, X.
Xu, Z.
Tematy:: hesitant fuzzy set
minimal spanning tree
graph theory-based clustering algorithm
hesitant fuzzy distance; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Badań Systemowych PAN
Powiązania:: https://bibliotekanauki.pl/articles/205680.pdf Link otwiera się w nowym oknie
Opis:: Hesitant fuzzy sets (HFSs) are useful means to describe and deal with uncertain data. In this article, a minimal spinning tree (MST) algorithm based clustering technique under hesitant fuzzy environment is proposed. We first introduce the concepts of graph, MST, HFS, and hesitant fuzzy distance. Then, we present a hesitant fuzzy MST clustering algorithm to perform clustering analysis of HFSs via some hesitant fuzzy distances, and finally illustrate the effectiveness of our algorithm through two numerical examples.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Effect of pH on adsorption and desorption of hexadecyl trimethyl ammonium bromide from silicate surface
Autorzy:: Karaguzel, C.
Xu, Z.
Tematy:: adsorption
silica sensor
hexadecyl trimethyl ammonium bromide
quartz crystal micro-balance with dissipation monitoring; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110257.pdf Link otwiera się w nowym oknie
Opis:: Hexadecyl trimethyl ammonium bromide (HTAB), a cationic surfactant, is physically adsorbed on negatively charged silicate surfaces due to electrostatic forces. This reversible adsorption process is important for surfactant regeneration in some industrial applications such as waste water treatment. Cationic surfactant adsorption and desorption from silica surfaces were studied using several methods such as UV, FTIR, XPS, and XRD. However, most of these methods are time independent and ex situ in nature. Quartz crystal microbalance with dissipation monitoring (QCM-D) is a power tool that can determine the amount and thickness of the deposited material on the surface in situ as a function of time. In this study, the adsorption and desorption characteristic of HTAB was studied on the silica sensor surface by using QCM-D. The adsorption and desorption tests were performed at a constant HTAB concentration (5·10-4 M, close to CMC of HTAB) at different pH values (3, 5.5, 6.5 and 10). The results obtained from these studies clearly showed that pH is a critical factor determining the adsorption and desorption processes.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Decay of Electric Charge on Corona Discharge Polyethylene
Autorzy:: Zhang, L.
Xu, Z.
Chen, G.
Tematy:: 52.80.-s
81.05.Lg
84.30.Jc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1807998.pdf Link otwiera się w nowym oknie
Opis:: In this paper, surface potential decay after corona charge deposition has been investigated for low density polyethylene (LDPE) films. We believe that the three ways of electron charge decay on the surface of insulating polyethylene film is reasonable. The factor of neutralizing with opposite charge in air is negligible, and leakage along insulator surface or through the body is much more important for electron charge decay. Both ways are related with surface voltage of the sample. When the voltage is lower than a critical value, surface leakage contributes most. If the voltage is higher than this value, the electron energy on the surface of the sample exceeds the critical value and it is easy to cross the "deep trap". In this situation, the body leakage is more important, and the decay on the surface of sample speeds. That is why there exists decay curve crossing phenomenon.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Thermal Decomposition Characteristics of Ammonium Nitrate(V) in the Presence of Mn2O3/Graphene Oxides
Autorzy:: Xu, Z.
Xu, G.
Fu, X.
Wang, Q.
Tematy:: ammonium nitrate(V)
nano-oxides
graphene oxide
thermal decomposition
RSFTIR; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358837.pdf Link otwiera się w nowym oknie
Opis:: Nano-composites (Mn2O3, Mn2O3/graphene oxides (GO)) were prepared by a new method. The nano-composites were characterized by XRD and HRTEM. The catalytic performance of the nano-composites on the thermal decomposition of ammonium nitrate(V) (AN) was investigated by TG-DSC and TG-MS. The reaction of AN with the nano-composites in the condensed phase was investigated by RSFTIR. The results of TG-DSC experiments indicated that the nano-composites significantly catalyze the thermal decomposition of AN, especial Mn2O3/GO. The exothermic reaction of AN with Mn2O3/GO commenced at about 185 °C. Based on the TG-MS results, it was ascribed to N2O formation. In the RSFTIR experiments, the dissociation reaction and ionization reaction of AN were both detected. NOx formation at low temperature was also found. NH2 was directly oxidized by HNO3/NO3− at low temperature. The interaction between Mn2O3 and NH3 was detected according to DRIFT experiments. At elevated temperature, the functional groups of GO are destroyed, which had an influence on the interaction between Mn2O3 and GO. A probable mechanism for the exothermic reaction and then its disappearance is proposed. HNO3 gas was absorbed on the surface of solid AN, which can markedly catalyze the thermal decomposition of AN. Perhaps the HNO3 plays a key role in the exothermic reaction and then the reaction of AN disappears at very low temperatures.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Intervalley Transfer of Electrons in ZnS-Type Thin Film Electroluminescent Devices
Autorzy:: Zhao, H.
Wang, Y.
Xu, Z.
Xu, X.
Tematy:: 72.20.-i
78.60.-b; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2011094.pdf Link otwiera się w nowym oknie
Opis:: Based on the calculation about intervalley scattering rates in ZnS, the intervalley transfer process in ZnS-type thin film electroluminescent devices is investigated through the Monte Carlo simulation. The transient time of intervalley transfer is about 0.2-0.3 ps, it coincides with that of electron average energy. Intervalley distribution shifts to high valleys as the electric field increased. The electron kinetic energy distributions in different valleys are also gained. We propose that high valleys could store energies, which could prolong the decay of the electron average energy as the field was removed. These results could be used as the basic data on the study of electroluminescent process and the citation of valley parameters in analytic models should be carefully considered.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Phase Stability of Ammonium Nitrate with Organic Potassium Salts
Autorzy:: Xu, Z.-X.
Fu, X.-Q.
Wang, Q.
Tematy:: ammonium nitrate(V)
phase transition
organic compounds
differential scanning calorimetry; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358264.pdf Link otwiera się w nowym oknie
Opis:: A study has been undertaken on the effect of additives on the phase transition of ammonium nitrate(V) (AN). Results obtained using Differential Scanning Calorimetry (DSC) showed that organic compounds and potassium salts of organic compounds have an effect on the phase transition behavior of AN. The samples were further analyzed using infrared (IR) and powder X-ray diffraction (XRD). The mechanism of phase stabilization of AN by compounds of this kind was examined. The present study showed that the influence of additives on the phase transition of AN occurs through the polar groups that are involved in intermolecular interactions of orbital and electrostatic types that form new hydrogen bonds. AN exists in only one phase in the temperature range from 30 °C to +100 °C, when a potassium salt of organic compounds was added. However, with organic compounds, the III→II phase transition was changed. IR and XRD of composites are characterized by new intermolecular interactions. Compacted samples of AN containing potassium salts of organic compounds exhibited better stability than AN containing organic compounds to multiple cyclic changes within a temperature range. This we named ‘freezing and thawing analysis’. Additives have two functions on the AN phase transition. First, solid solutions of AN mixture were formed for K+ replacement of NH4+. Second, hydrogen bonds formed, which caused AN and salts of organic compounds to interact intimately.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Key-point Detection based Fast CU Decision for HEVC Intra Encoding
Autorzy:: Xu, Z.
Min, B.
Cheung, R. C. C.
Tematy:: HEVC
video coding
fast CU decision
corner detection; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/226128.pdf Link otwiera się w nowym oknie
Opis:: As the most recent video coding standard, High Efficiency Video Coding (HEVC) adopts various novel techniques, including a quad-tree based coding unit (CU) structure and additional angular modes used for intra encoding. These new techniques achieve a notable improvement in coding efficiency at the penalty of significant computational complexity increase. Thus, a fast HEVC coding algorithm is highly desirable. In this paper, we propose a fast intra CU decision algorithm for HEVC to reduce the coding complexity, mainly based on a key-point detection. A CU block is considered to have multiple gradients and is early split if corner points are detected inside the block. On the other hand, a CU block without corner points is treated to be terminated when its RD cost is also small according to statistics of the previous frames. The proposed fast algorithm achieves over 62% encoding time reduction with 3.66%, 2.82%, and 2.53% BD-Rate loss for Y, U, and V components, averagely. The experimental results show that the proposed method is efficient to fast decide CU size in HEVC intra coding, even though only static parameters are applied to all test sequences.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Infuence of Iron Ion on Thermal Behavior of Ammonium Nitrate and Emulsion Explosives
Autorzy:: Xu, Z.
Liu, D.
Hu, Y.
Ye, Z.
Wei, Y.
Tematy:: Accelerating Rate Calorimeter (ARC)
ammonium nitrate
critical temperature
emulsion explosives
thermal stability; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/357932.pdf Link otwiera się w nowym oknie
Opis:: The infuence of ferric nitrate on the thermal stability of ammonium nitrate and emulsion matrix were used to study with Accelerating Rate Calorimeter (ARC) and constant temperature thermal decomposition experiment in this paper. It is shown that ferric nitrate has signifcant catalytic property to the ammonium nitrate and emulsion matrix, which decrease the initial decomposition temperature of ammonium nitrate by 60.16 C and emulsion matrix by 30.33 C. The results of the infuence of ferric nitrate on catalysis of ammonium nitrate using ARC and constant temperature thermal decomposition experiment are the same. The most probable mechanism function, activation energy and the preexponential factor of ammonium nitrate with ferric nitrate were determined to be f(α) = 1-α, E = 195.41 kJ/mol, A = 2.08×1019 s-1. The kinetics of ammonium nitrate decomposition can be used to calculate the critical temperatures for ammonium nitrate decomposition with and without the presence of ferric nitrate, based on the Frank-Kamenetskii model of thermal explosion. Furthermore, as the iron-plate experiment shows, ferric nitrate can signifcantly reduce the critical temperature of emulsion matrix decomposition. Once the ferric nitrate interfuses in the ammonium nitrate and emulsion matrix, the thermal stability of ammonium nitrate and emulsion matrix is decreasing.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Effect of overlying water pH, dissolved oxygen and temperature on heavy metal release from river sediments under laboratory conditions
Autorzy:: Huang, Y.
Zhang, D.
Xu, Z.
Yuan, S.
Li, Y.
Wang, L.
Tematy:: heavy metal
release
river sediment; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/204852.pdf Link otwiera się w nowym oknie
Opis:: The heavy metal release experiments were conducted in the laboratory to examine the effects of 3 factors - pH, dissolved oxygen (DO), and temperature on the metal release from sediments taken from the Huangpu River. The metal concentrations in the dry sediments ranged from 0.030 to 0.296 mg g^-1 for Cr, 0.021 to 0.097 mg g^-1 for Ni, 0.014 to 0.219 mg g^-1 for Cu, 0.035 mg to 0.521 mg g^-1 for Zn, 0.0002 to 0.001 mg g^-1 for Cd and 0.023 to 0.089 mg g^-1 for Pb. Most of the metals found in the sediments were in the form of residual fraction, the exchangeable fraction consisted of only a small portion of total metals. The average dissolved metal concentrations in the overlying water during the 13-day period under different conditions were ranging from 0.82 to 1.93 μg L^-1 for Cr, 1.08 to 4.19 μg L^-1 for Ni, 40.79 to 82.28 μg L^-1 for Cu, 20.30 to 29.96 μg L-1 for Zn, 1.57 to 4.07 μg L^-1 for Cd, and 22.26 to 75.50 μg L^-1 for Pb, respectively. Statistical interpretation of the data indicated that pH (7, 8, 9), dissolved oxygen DO (1.0 and 5.0 mg L^-1) and temperature (4, 16, 25°C) had no significant effects on the heavy metal release under the studied conditions. Cu and Pb had the highest release flux, while Cd, Pb and Cu had higher mobility. The main factors controlling the metals release might be the inherent characters of metals and sediments.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Effect of Mg and Ca on the Characteristics of Inclusions in Sulphur Steel
Autorzy:: Tian, J.
Qu, T.
Wang, D.
Wang, H.
Xu, Z.
Xinrui, E.
Tematy:: Mg treatment
Ca treatment
MnS
complex sulfide
inclusions; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/355348.pdf Link otwiera się w nowym oknie
Opis:: The effects of Mg and Ca on sulfide modification of sulphur steel were studied to elucidate the difference between micromagnesium treatment and micro-calcium treatment for the inclusion of sulphur steel. The results show that the inclusions in the steel appeared with an oxide core of Al₂O₃ and MnS wrapped. After the addition of Mg, the core was changed to spinel, and the MnS coating was changed to Mn-Mg-S. After Ca was added, the core was changed to Ca-Al-O, and the MnS coating was changed to Mn-Ca-S. The Mg content was higher than Ca content in the sulfides of the steel. Therefore, Mg was more effective than Ca in terms of sulfide modification with the same content of Mg and Ca in steel, but the yielding rate of Mg was lower than that of Ca. The Mg content in the oxide core was higher than Mg of the coating of the inclusions in the steel treated with Mg or Mg-Ca. In contrast, the Ca content in the oxide core was lower than Ca of the coating of the inclusions in the steel treated with Ca or Mg-Ca. MnS formed and precipitated during the melt solidification process. The complex sulfide (Mg-Mn-S) was precipitated around MgO·Al₂O₃ in the Mg treated steel during the cooling process. CaS inclusion was precipitated on the CaO·Al₂O₃ inclusions in the liquid Ca-treated steel. Thus, CaS was formed first, whereas MnS was formed during the cooling process, followed by the formation of complex sulfide (CaS+MnS), which finally precipitated around CaO·Al₂O₃ in the Ca-treated steel.
Dostawca treści:: Biblioteka Nauki

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