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Tytuł:
Shear Bond Strength Comparison between Conventional Dental Nano Zirconia Combinations and New Functionally Graded Nano Zirconia Combinations after Thermal-Mechanical Cycling
Autorzy:
Sun, T.
Lai, R.
Liu, R.
Shao, L.
Powiązania:
https://bibliotekanauki.pl/articles/1215622.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jc
Opis:
The aim of the study was to evaluate the core-veneer bond strength of graded zirconia combinations and compared those to conventional zirconia combinations after thermal and mechanical tests. Conventional zirconia-veneer combinations and graded zirconia-veneer combinations were made into cylinders. Prior to shear bond testing, half of each group was subjected to thermal and mechanical cycling testing at three conditional levels. All specimens were thereafter subjected to a shear force. The fractured surfaces were visually analyzed with scanning electron microscopy. The shear bond strength values of functionally graded zirconia combinations were significantly higher than zirconia combinations, irrespective of the fatigue conditions (P < 0.05). The shear bond strength values of graded zirconia combinations and zirconia combinations before thermal-mechanical cycling were higher than after (P < 0.05). The shear bond strength values of graded zirconia combinations was $40.99 ± 2.22$ MPa, $39.44 ± 2.36$ MPa, $37.45 ± 2.06$ MPa, and $36.87 ± 2.18$ MPa for conditions 0 to 3, respectively. The shear bond strength values were $26.75 ± 2.16$ MPa, $23.95 ± 2.16$ MPa, $21.65 ± 2.14$ MPa, and $20.49 ± 2.16$ MPa for zirconia combinations from conditions 0 to 3, respectively. The functionally graded zirconia combinations exhibited greater shear bond strength than zirconia combinations, irrespective of the fatigue conditions. Thermal-mechanical cycling had an impact on the shear bond strength of both graded zirconia combinations and conventional zirconia combinations.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 238-240
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption kinetics of fluoride on bone char and its regeneration
Autorzy:
Hu, J.
Wu, D.
Rao, R.
Liu, R.
Lai, W.
Powiązania:
https://bibliotekanauki.pl/articles/206892.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
chlorine compounds
fluorine compounds
ions
sodium compounds
sulfur compounds
adsorption kinetics
chemical reaction equilibrium
correlation coefficient
Freundlich equation
optimal conditions
layered double hydroxides
aqueous-solution
drinking water
equilibrium
adsorbent
związki chloru
związki fluoru
jod
związki sodu
związki siarki
kinetyka adsorpcji
równowaga reakcji chemicznej
współczynnik korelacji
równanie Freundlicha
woda pitna
równanie Langmuira
Opis:
The adsorbent of bone char (BC), produced from the pyrolysis of crushed animal bones, was dominated by the mesopores of the Brunauer Emmett Teller (BET) surface area. The optimal condition for defluoridation with BC was a pH level near 5.0. Chloride and nitrate ions could increase fluoride adsorption capacity in contrast with the effect of sulfate and carbonate ions. The interchangeability between fluoride and hydroxyl groups on BC sorbent was proved by the Fourier transform infrared spectroscopy. Langmuir equation had a better correlation coefficient than the Freundlich equation at various temperatures. Thermodynamic parameters such as Delta G degrees, Delta H degrees, Delta S degrees, Ea and S*, have been calculated to describe the nature of fluoride adsorption onto BC. Negative Delta G degrees and Delta H degrees values at various temperatures indicate a spontaneous process, and its exothermic effect, respectively. However, a positive Delta S degrees value represents an increasing process for entropy. The E-a and S* values ranging from 5 to 40 kj.mol-1 and 0 to 1, respectively, demonstrated that the adsorption is dominated by physical process, although the adsorption kinetic process was involved external diffusion, intraparticle diffusion and chemical reaction equilibrium stage. A high concentration of NaOH solution increases efficiency of removing adsorbed F- ions from the BC surface.
Źródło:
Environment Protection Engineering; 2017, 43, 3; 93-112
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancing the Thermal Protective Performance of Firefighters Protective Fabrics by Incorporating Phase Change Materials
Polepszenie właściwości termicznych odzieży ochronnej strażaków poprzez zastosowanie materiałów zmiennofazowych
Autorzy:
Zhu, F L
Feng, Q Q
Liu, R
Yu, B
Zhou, Y
Powiązania:
https://bibliotekanauki.pl/articles/231560.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
phase change material
fire protective clothing
thermal protective performance
materiał zmiennofazowy
odzież ochronna
ochrona termiczna odzieży
Opis:
A composite fabric consisting of an outer shell, moisture barrier, thermal liner and comfort layer used for firefighters’ protective clothing, was incorporated with shape-stabilised phase change material (PCM) powder in order to improve the thermal protection capability provided by thermal protective clothing. Then we conducted a series of FTP (fire testing protection) experiments to investigate the effects of PCM location and phase change temperature on the heat protection efficiency of firefighters’ protective fabrics (FFPFs). Simultaneously the thermoregulation performance of the composite fabrics with PCMs was evaluated by using step-cooling experimental technology during the cooling process. Data from the FTP tests were also compared with those from the existing enthalpy formulation model of heat transfer through FFPFs embedded with PCMs. It was concluded that the use of PCMs could improve the heat buffering capacity. However, as PCM has a moderate melting temperature, it is better than the other two samples because they have a lower and higher melting temperature. Therefore PX 52 PCMs (melting temperature: 47 - 53 °C) could provided the maximum heat protection time compared with the other two kinds of PCMs.
W celu zwiększenia zdolności ochrony termicznej odzieży ochronnej dla strażaków, przy użyciu stabilizowanego materiału zmiennofazowego w postaci proszku, stworzono materiał kompozytowy składający się z powłoki zewnętrznej, warstwy stanowiącej barierę dla wilgoci, wkładki termicznej i warstwy zapewniającej komfort. W celu zbadania wpływu umieszczenia materiału zmiennofazowego i temperatury przemiany fazowej na efektywność ochrony cieplnej przeprowadzono serię eksperymentów (testy ochrony przeciwpożarowej). Jednocześnie oceniono zdolność termoregulacji tkanin kompozytowych, oceny tej dokonano stosując technikę stopniowego chłodzenia. Dane z badań porównano z danymi teoretycznymi. Stwierdzono, że stosowanie materiałów zmiennofazowych może poprawić zdolność buforowania ciepła. Określono optymalny rodzaj materiału zmiennofazowego.
Źródło:
Fibres & Textiles in Eastern Europe; 2015, 2 (110); 68-73
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High pressures studies on hydrides of selected manganese alloys
Autorzy:
Sugiura, H.
Filipek, S.
Paul-Boncour, V.
Marchuk, I.
Liu, R.
Pyun, S.
Powiązania:
https://bibliotekanauki.pl/articles/146225.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
deuterides/hydrides
high pressure
ferromagnetic fcc-manganese
Laves phases
equation of state
Opis:
Specific behavior found in hydrides formed in manganese, Mn-Ni and YMn2 under high pressure is presented and discussed. The synthesis of ferromagnetic fcc-manganese was proved. Parameters of the equations of state (EOS) derived from measurements in the diamond anvil cell (DAC) are summarized for manganese hydrides and for hydrides derived from YMn2 Laves phase. It was found that the compression behavior of recently discovered YMn2H6 is different from YMn2-based hydrides with lower hydrogen content.
Źródło:
Nukleonika; 2006, 51,suppl.1; 73-77
0029-5922
1508-5791
Pojawia się w:
Nukleonika
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:
XANES Study of La$\text{}_{0.75-x}$Gd$\text{}_{x}$Ca$\text{}_{0.25}$MnO$\text{}_{3-δ}$ Solid Solutions
Autorzy:
Drozd, V. A.
Pęka̶a, M.
Liu, R. S.
Lee, J.-F.
Chen, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2046755.pdf
Data publikacji:
2006-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
61.10.Ht
Opis:
A series of solid solutions La$\text{}_{0. 75-x}$Gd$\text{}_{x}$Ca$\text{}_{0.25}$MnO$\text{}_{3-δ}$ with 0.0≤x≤0.75 was prepared via carbonate precursor precipitation method. Final sintering was performed at 1250ºC in oxygen flow atmosphere. The samples obtained were characterized by scanning electron microscope, X-ray diffraction measurements. Oxygen stoichiometry was analyzed by iodometric titration method. X-ray absorption spectroscopic methods of Mn L-edge and Mn K-edge X-ray absorption near edge structure were used to study oxidation state of manganese in the solid solutions and elucidate features of their local crystal structure. Orthorhombic crystal structure characteristics of the solid solutions were refined by Rietveld method. An increase in oxygen deficiency and average manganese oxidation state were found to accompany Gd concentration increase in La$\text{}_{0.75-x}$Gd$\text{}_{x}$Ca$\text{}_{0.25}$MnO$\text{}_{3-δ}$. These results are consistent with Mn L-edge X-ray absorption near edge structure spectra, where a gradual change of Mn oxidation state with Gd concentration increase was detected. Origins of oxygen deficiency La$\text{}_{0.75- x}$Gd$\text{}_{x}$Ca$\text{}_{0.25}$MnO$\text{}_{3-δ}$ are discussed in terms of structural disorder caused by Gd substitution for La.
Źródło:
Acta Physica Polonica A; 2006, 109, 4-5; 583-589
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of the Energetic Additive Coated MgH2 on the Power of Emulsion Explosives Sensitized by Glass Microballoons
Autorzy:
Cheng, Y.
Wang, Q.
Liu, F.
Ma, H.
Shen, Z.
Guo, Z.
Liu, R.
Powiązania:
https://bibliotekanauki.pl/articles/357940.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
emulsion explosive
power
hydrogen storage material
magnesium hydride
Opis:
Traditional emulsion explosives, in spite of excellent water resistance, safe handling and good storage performance, have low power problems which seriously hinders their use. In order to improve the power of emulsion explosives, a hydrogen based emulsion explosive was devised. Scanning electron microscope pictures and experimental storage results show that the coating effect and stability of coated magnesium hydride (MgH2) are very good. The power of an emulsion explosive sensitized by glass microballoons was significantly increased (24.30 mm compression of lead block) after adding coated MgH2, compared to only 16.10 mm compression when not added. Thus emulsion explosives with coated MgH2 as an energetic additive have many potential applications.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 3; 705-713
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, Crystal Structure, and Properties of a Novel, Highly Sensitive Energetic, Coordination Compound: Iron (II) Carbohydrazide Perchlorate
Autorzy:
Liu, R.
Zhou, Z.
Qi, S.
Yang, L.
Wu, B.
Huang, H.
Zhang, T.
Powiązania:
https://bibliotekanauki.pl/articles/358343.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
iron (II) carbohydrazide perchlorate
energetic material
high
sensitivity
DFT
energy gap
Opis:
A single crystal of iron (II) carbohydrazide perchlorate [FeII (CHZ)3](ClO4)2 (FeCP), a novel, lead-free, energetic coordination compound, was synthesized and its structure determined by X-ray single crystal diffraction for the frst time. The crystal belongs to the monoclinic system P2(1)/n space group, with a = 1.0066(2) nm, b = 0.8458(2) nm, c = 2.1194(4) nm, β = 100.693(3)° and Z = 4. The central Fe(II) ion is coordinated to three bidentate carbohydrazide units through the carbonyl oxygen atom and an amino nitrogen atom, forming a six-coordinated, non-centrosymmetric complex cation. The thermal analyses by differential scanning calorimetry and thermogravimetry show that the onset temperature of thermal decomposition (152.7 °C) and the critical temperature of thermal explosion of FeCP (161.2 °C) are both much lower than those of other transition metal carbohydrazide perchlorate compounds, and also those of some other primary explosives in service. FeCP has a high enthalpy of combustion, as measured by oxygen bomb calorimetry. The impact, friction and fame sensitivity tests indicate that FeCP is extremely sensitive and hazardous. Unexpected explosions occurred even during the operational processes. In order to explore the intrinsic cause of these explosions, theoretical calculations of the orbital energies were performed based on DTF. These results reveal that the impact sensitivity is positively correlated with the energy gap between HOMO and LUMO: the smaller energy gap results in the higher impact sensitivity.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 1; 17-36
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ship trajectory tracking control system design based on sliding mode control algorithm
Autorzy:
Liu, Y.
Bu, R.
Gao, X.
Powiązania:
https://bibliotekanauki.pl/articles/259621.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
LOS
ship trajectory
tracking control system
sliding mode control
Opis:
The paper reports the design and tests of the planar autopilot navigation system in the three-degree-of-freedom (3-DOF) plane (surge, sway and yaw) for a ship. The aim of the tests was to check the improved maneuverability of the ship in open waters using the improved nonlinear control algorithm, developed based on the sliding mode control theory for the ship-trajectory tracking problem of under-actuated ships with static constraints, actuator saturation, and parametric uncertainties. With the integration of the simple increment feedback control law, the dynamic control strategy was developed to fulfill the under-actuated tracking and stabilization objectives. In addition, the LOS (line of sight) guidance system was applied to control the motion path, whereas the sliding mode controller was used to emulate the rudder angle and propeller rotational speed control. Firstly, simulation tests were performed to verify the validity of the basic model and the tracking control algorithm. Subsequently, full scale maneuverability tests were done with a novel container ship, equipped with trajectory tracking control and sliding mode controller algorithm, to check the dynamic stability performance of the ship. The results of the theoretical and numerical simulation on a training ship verify the invariability and excellent robustness of the proposed controller, which: effectively eliminates system chattering, solves the problem of lateral drift of the ship, and maintains the following of the trajectory while simultaneously achieving global stability and robustness.
Źródło:
Polish Maritime Research; 2018, 3; 26-34
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simultaneous disturbance compensation and Hi/H∞ optimization in fault detection of UAVs
Autorzy:
Liu, H.
Zhong, M.
Yang, R.
Powiązania:
https://bibliotekanauki.pl/articles/331045.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fault detection
disturbance compensation
unmanned aerial vehicle
detekcja uszkodzeń
kompensacja zakłóceń
bezzałogowy statek powietrzny
Opis:
This paper deals with the problem of robust fault detection (FD) for an unmanned aerial vehicle (UAV) flight control system (FCS). A nonlinear model to describe the UAV longitudinal motions is introduced, in which multiple sources of disturbances include wind effects, modeling errors and sensor noises are classified into groups. Then the FD problem is formulated as fault detection filter (FDF) design for a kind of nonlinear discrete time varying systems subject to multiple disturbances. In order to achieve robust FD performance against multiple disturbances, simultaneous disturbance compensation and Hi/H∞ optimization are carried out in designing the FDF. The optimality of the proposed FDF is shown in detail. Finally, both simulations and real flight data are applied to validate the proposed method. An improvement of FD performance is achieved compared with the conventional Hi/H∞-FDF.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2018, 28, 2; 349-362
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Evaluation Analysis of the Indicator Information in Nuclear Safeguards Applications by Computing With Words
Autorzy:
Liu, J.
Ruan, D.
Carchon, R.
Powiązania:
https://bibliotekanauki.pl/articles/908042.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fizyka
safeguards
computing with words
decision-making
physical model
Opis:
This paper aims at the handling and treatment of nuclear safeguard relevant information by using a linguistic assessment approach. This is based on a hierarchical analysis of a State's nuclear activities in a multi-layer structure of the evaluation model. After a hierarchical analysis of the State's nuclear activities on the basis of the IAEA Physical Model, the addressed objective is divided into several less complex levels. The overall evaluation can be obtained step by step from those lower levels. Special emphasis is put on the synthesis and evaluation analysis of the Physical Model indicator information. Accordingly, the aggregation process with the consideration of the different kinds of qualitative criteria is in focus. Especially, the symbolic approach is considered by the direct computation on linguistic values instead of the approximation approach using the associated membership function. In this framework, several kinds of ordinal linguistic aggregation operators are presented and analyzed. The application of these linguistic aggregation operators to the combination of the Physical Model indicator information is provided. An example is given to support and clarify the mathematical formalism.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 3; 449-462
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An integrated production and delay-time based preventive maintenance planning model for a multi-product production system
Model integrujący planowanie opartej na pojęciu czasu opóźnienia konserwacji zapobiegawczej oraz planowanie produkcji dla systemów produkcji wieloasortymentowej
Autorzy:
Liu, X.
Wang, W.
Peng, R.
Powiązania:
https://bibliotekanauki.pl/articles/1365965.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
production planning
preventive maintenance
delay time
integration
multi-product
planowanie produkcji
konserwacja zapobiegawcza
czas opóźnienia
integracja
wieloasortymentowy
Opis:
This paper integrates preventive maintenance and medium-term tactical production planning in a multi-product production system. In such a system, a set of products needs to be produced in lots during a specified finite planning horizon. Preventive maintenance is carried out periodically at the end of some production periods and corrective maintenance is always performed at failures. The system’s available production capacity can be affected by maintenance, since both planned preventive maintenance and unplanned corrective maintenance result in downtime loss during the planning horizon. In addition to the time used for preventive and corrective maintenance, our model considers the setup time and the product quality, as these are affected by the defects and failures of the system. Procedures are proposed to identify the optimal production plan and preventive maintenance policy simultaneously. Our objective is to minimize the sum of maintenance, production, inventory, setup, backorder costs and the costs of unqualified products within the planning horizon. A real case from a steel factory is presented to illustrate the model.
W niniejszej pracy zintegrowano proces konserwacji zapobiegawczej z procesem średnioterminowego taktycznego planowania produkcji w odniesieniu do systemu produkcji wieloasortymentowej. W takim systemie, zestaw wyrobów jest produkowany partiami w określonym, skończonym horyzoncie planowania. Konserwacja zapobiegawcza prowadzona jest okresowo pod koniec wybranych okresów produkcyjnych, natomiast w przypadku wystąpienia uszkodzenia wykonuje się konserwację korygującą. Konserwacja może mieć wpływ na dostępne moce produkcyjne systemu, jako że zarówno planowana konserwacja prewencyjna jak i nieplanowana konserwacja korygująca powodują straty związane z przestojem urządzeń w danym horyzoncie planowania. Oprócz czasu potrzebnego na konserwację zapobiegawczą i korygującą, nasz model uwzględnia czas konfiguracji urządzeń oraz jakość produktów, ponieważ one również zależą od defektów i awarii systemu. Zaproponowano procedury, które pozwalają na jednoczesne określenie optymalnego planu produkcji i optymalnej strategii konserwacji prewencyjnej. Naszym celem jest minimalizacja sumy kosztów konserwacji, produkcji, zapasów, konfiguracji urządzeń oraz zamówień oczekujących a także kosztów produktów, które nie zostały zakwalifikowane do wprowadzenia do obrotu w danym horyzoncie planowania. Model zilustrowano na przykładzie rzeczywistego przypadku z fabryki stali.
Źródło:
Eksploatacja i Niezawodność; 2015, 17, 2; 215-221
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scanning Tunneling Microscopy of Ordered Organic Monolayer Films on Si(001)
Autorzy:
Hamers, R. J.
Hovis, J.
Liu, H.
Powiązania:
https://bibliotekanauki.pl/articles/1968711.pdf
Data publikacji:
1998-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.Ch
34.50.Dy
68.55.-a
Opis:
Scanning tunneling microscopy and optical spectroscopy techniques have been utilized to investigate the formation of ordered organic monolayer films on the (001) face of silicon. Cyclopentene and 1,5-cyclooctadiene both produce monolayer films that are ordered translationally and rotationally. The rotational orientations of the molecules arise from the directional interaction of the π orbitals of the starting alkene with the π orbital of the dimers comprising the reconstructed Si(001) surface, with the Si(001) surface acting as a template for determining the directionality of molecules in the subsequent organic film. Using single-domain Si(001) samples, it is shown that the molecular films also exhibit anisotropy in optical properties when measured on centimeter length scales.
Źródło:
Acta Physica Polonica A; 1998, 93, 2; 289-295
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal aging of hydrogenated nitrile rubber – loss of additives and its influence on elasticity maintenance
Starzenie termiczne uwodornionego kauczuku nitrylowego – ubytek dodatków i jego wpływ na zachowanie elastyczności
Autorzy:
Liu, X.
Zhao, J.
Yang, R.
Iervolino, R.
Barbera, S.
Powiązania:
https://bibliotekanauki.pl/articles/945800.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
hydrogenated nitrile rubber
thermal aging
additives
elasticity
uwodorniony kauczuk nitrylowy
starzenie termiczne
dodatki
elastyczność
Opis:
The thermal aging of hydrogenated nitrile rubber (HNBR) at elevated temperatures 125 and 150 °C was investigated. The changes of chemical structures, including functional groups and crosslinking density, and the changes of mechanical properties, including recovery from bending (RFB), tensile strength, elongation at break and Young's modulus, were determined. In addition, the loss of additives was analyzed by pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The aging procedure of HNBR exhibited two stages: loss of additives along with the deterioration of elasticity; obvious oxidation and extra crosslinking with further hardening and embrittlement. The relationship between the deterioration of elasticity and the loss of plasticizers was established. It was demonstrated that the failure of HNBR happened long before obvious oxidation and crosslinking of the rubber chains, and the loss of additives, especially the loss of plasticizers, was the main reason for the failure. Therefore, the elasticity recovery of aged HNBR immersed in the plasticizer (n-propyl palmitate as a model) was carried out. This treatment was demonstrated to be effective before obvious oxidation and crosslinking of HNBR occurred during the thermal aging.
Badano starzenie termiczne uwodornionego kauczuku nitrylowego (HNBR) w temperaturze 125 i 150 °C. Określono zmiany struktur chemicznych, w tym grup funkcyjnych i gęstości usieciowania oraz zmiany właściwości mechanicznych, w tym powrotu poodkształceniowego po zginaniu (RFB), wytrzymałości na rozciąganie, wydłużenia przy zerwaniu i modułu Younga. Ponadto metodą pirolitycznej chromatografii gazowej z detekcją mas (Py-GC/MS) analizowano straty dodatków obecnych w kauczuku. Procedura starzenia się HNBR wykazywała dwa etapy: ubytek dodatków wraz z pogorszeniem elastyczności; wyraźne utlenianie i dodatkowe sieciowanie związane z dalszym utwardzaniem i zwiększaniem kruchości. Określono zależność pomiędzy zmniejszaniem się elastyczności a ubytkiem dodatków zmiękczających. Wykazano, że pogorszenie właściwości HNBR następowało znacznie wcześniej niż utlenianie i sieciowanie oraz było spowodowane utratą dodatków, a zwłaszcza plastyfikatorów. W związku z tym przeprowadzono próbę odtworzenia elastyczności starzonych próbek HNBR przez zanurzenie w plastyfikatorze (palmitynian n-propylu jako model). Obróbka ta okazała się skuteczna, pod warunkiem przeprowadzenia jej zanim podczas starzenia termicznego nastąpiło utlenianie i sieciowanie HNBR.
Źródło:
Polimery; 2017, 62, 7-8; 588-598
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Isolation and genetic analysis of a variant porcine epidemic diarrhea virus in China
Autorzy:
Li, R.-f.
Tian, X.-g.
Liu, Y.
Xu, J.
Liu, D.-y.
Powiązania:
https://bibliotekanauki.pl/articles/30492.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Porcine epidemic diarrhea virus (PEDV) is having a severe effect on the pig breeding industry in central China. The mucosa and the content of the small intestine from newborn pre-weaned piglets with diarrhea were tested for the presence of PEDV by molecular and morphologic methods, and found to be positive. Negative-staining electron microscopy (EM) revealed the presence of coronavirus- like particles in the samples. The result of molecular detection by nested RT-PCR based on the amplification of the M gene was positive. Using a novel alternative method we successfully propagated the PEDV strain (CH/QX-2) in Vero cells, confirmed by ultrathin sections of the cells and Immunofluorescence assay (IFA). Phylogenetic analysis based on the partial S gene showed that the CH/QX-2 isolate was genetically closer to strains more commonly found in China, but differed genetically from two domestic strains (CH/S, 1986 and LZC, 2007), Korean strains (DR13, 2007), and the vaccine strain (CV777 vs) currently being used in China. CH/QX-2 formed a unique clade in the derived phylogenetic tree indicating that the CH/QX-2 strain currently circulating in central China is a new variant of PEDV. This study extends current knowledge on the diversity and epidemiology of PEDV.
Źródło:
Polish Journal of Veterinary Sciences; 2016, 19, 1
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 45

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