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Tytuł:
Optical trapping forces of focused circular partially coherent beams on Rayleigh particles
Autorzy:
Yu, Chaoqun
Chen, Fuchang
Zeng, Jun
Huang, Cheng
He, Zhimin
Lin, Huichuan
Zhang, Yongtao
Chen, Ziyang
Pu, Jixiong
Powiązania:
https://bibliotekanauki.pl/articles/2172861.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tight focusing
radially polarized
circular partially coherent
spherical aberration
optical trapping force
Opis:
The optical trapping forces of tightly-focused radially polarized circular partially coherent beams on Rayleigh particles are theoretically investigated. Numerical calculations are performed to study the optical trapping forces on Rayleigh particles for different initial coherent length of the incident circular partially coherent beams. The results show that the magnitude of the gradient force decreases with the reduction of the initial coherent length of the focused radially polarized circular partially coherent beams, while the balanced position (i.e., the position where the optical trapping forces becomes zero) stays constant. Moreover, the focused spot gradually elongates along the optical axis with the reduction of the initial coherent length, and the axial gradient force on Rayleigh particles also decreases gradually with the reduction of the intensity gradient in axial direction. As there exists an spherical aberrant in the focusing optical system, the focal spot in the direction of the optical axis becomes trumpet-shaped, and the optical trapping forces on Rayleigh particles change as well.
Źródło:
Optica Applicata; 2022, 52, 4; 575--583
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Pressure-Dependent Plasticity Model for Polymer Bonded Explosives under Confined Conditions
Autorzy:
Wei, Qiang
Huang, Xi-cheng
Chen, Peng-wan
Liu, Rui
Powiązania:
https://bibliotekanauki.pl/articles/27787985.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
polymer bonded explosives
constitutive model
damage model
confining pressure
mechanical response
Opis:
The safety of explosives is closely related to the stress state of the explosives. Under some stress stimulation, explosives may detonate abnormally. It is of great significance to accurately describe the mechanical response of explosives for the safety evaluation of explosives. The mechanical properties of polymer bonded explosives (PBXs) strongly depend on pressure. In this study, the mechanical behaviour of PBXs under confined conditions was investigated. It was found that the stress-plastic strain response of a PBX under high confining pressures is a combination of the non-linear and linear hardening portions. However, the linear hardening portion has often been neglected in characterizing the mechanical behaviour of a PBX under such pressures. The Karagozian and Case (K&C) model was applied to characterize the mechanical behaviour of PBXs. The numerical results demonstrated that when the confining pressure was high, the K&C model could not adequately match the experimental data due to the limitation of the damage model. Therefore, a new damage model was developed by means of considering intragranular damage and transgranular damage. This modification made it possible to introduce a linear hardening process into the original K&C model. The method proposed to describe the stress-strain results under high confining pressures was to consider the stress-plastic strain curve, including the nonlinear and linear hardening portions. The damage evolution of the original K&C model and a linear hardening model were applied for the nonlinear and linear hardening portions respectively. The influence of the linear hardening model on the damage evolution of the original K&C model was included when describing the nonlinear hardening portion. A comparison between simulation and experiment showed that the modified K&C model could well describe the mechanical response of PBXs under different confining pressures.
Źródło:
Central European Journal of Energetic Materials; 2021, 18, 3; 339--368
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhibiting effect of citric acid on the floatability of serpentine activated by Cu(II) and Ni(II) ions
Autorzy:
Huang, Jun-wei
Zhang, Cheng-qiang
Powiązania:
https://bibliotekanauki.pl/articles/110224.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
copper ion
nickel ion
serpentine
floatation
activation
inhibiting
Opis:
The laboratory researches about the inhibiting effect of citric acid on the flotation performance of serpentine activated by Cu2+ and Ni2+ were carried out through micro flotation tests, zeta potential measurements, collector adsorption capacity measurements and solution chemistry analysis. The flotation results showed that Cu2+ and Ni2+ could remarkably activate the flotation of serpentine when the pH value was more than 6, however, this activation could be effectively weakened by adding citric acid. Zeta potential measurement and adsorption capacity measurement indicated that the presence of citric acid could prevent the adsorption of Cu2+ and Ni2+, and therefore reduce the adsorption amount of potassium butyl xanthate on serpentine surface. Furthermore, solution chemical analysis of the flotation system showed that copper hydroxide Cu(OH)2(s) and the nickel hydroxide Ni(OH)2(s) were the main component in the pH range of 9 to 10, which adsorbed onto serpentine surface and made it activated; while the citric acid could effectively prohibit the formation of these metal hydroxide in slurry so as to inhibit the activation impact.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 4; 960-968
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the Microstructure, Electrical and Mechanical Properties of Hot Pressing Cr-50 Mass% Ni Alloys Fabricated by Addition of Various Ratios of Nanosized Ni Powders
Autorzy:
Huang, Jhong-Ren
Chang, Shih-Hsien
Liao, Cheng-Liang
Powiązania:
https://bibliotekanauki.pl/articles/2125538.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrical conductivity
hot pressing
transverse rupture strength
nanosized nickel powders
Cr-50 mass% Ni alloy
Opis:
In this work, nanosized Ni (nNi) powders of 50 nm are mixed with Cr and Ni submicron-powders (600 nm) to fabricate Cr-50 mass% Ni alloys by vacuum hot pressing. In order to evaluate the influence of the nanosized Ni powders, different amounts of nanosized Ni powders are added to produce the Cr-(50-x) mass% Ni-x mass% nNi alloys (x = 0, 10, 20, and 30). The hot pressing was maintained at 1275°C, 48 MPa for 1 h. The microstructure evaluation, mechanical, and electrical properties were performed. The results reveal that mechanical and electrical properties are enhanced when increasing the nNi addition. The Cr-20 mass% Ni-30 mass% nNi presents the highest relative density of 96.53% and the electrical conductivity of 2.18×104 Scm-1, moreover, the hardness and transverse rupture strength values increase to 76.1 HRA and 1217 MPa, respectively. Moreover, a more homogeneous microstructure and a decrease in the mean grain size to 3.15 μm are acquired. Significantly, this fabrication procedure (adding 30 mass% nanosized nickel powders) results in the optimal microstructure, electrical and mechanical properties of submicron-structured Cr-(50-x) mass% Ni-x mass% nNi alloys.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 3; 955--961
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of the height of overburden fractured zone in deep coal mining: case study
Prognozowanie wysokości strefy spękań w warstwach nadkładu w podziemnych kopalniach węgla: studium przypadku
Autorzy:
Han, Y.
Cheng, J.
Huang, Q.
Zou, D. H. S.
Zhou, J.
Huang, S.
Long, Y.
Powiązania:
https://bibliotekanauki.pl/articles/218745.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
wysokość strefy spękań w warstwie nadkładu
symulacje numeryczne
układ ortogonalny
pomiary in-situ
the hei ght of overburden fractured zone
numerical simulation
orthogonal design
in-situ test
Opis:
In the process of coal extraction, a fractured zone is developed in the overburden above the goaf. If the fractured zone is connected with an aquifer, then water inrush may occur. Hence, research and analysis of the height of overburden fractured zone (HOFZ) are of considerable significance. This study focuses on the HOFZ determination in deep coal mining. First, general deformation failure characteristics of overburden were discussed. Second, a new method, numerical simulation by orthogonal design(NSOD), have been proposed to determinate the HOFZ in deep coal mining. Third, the validity of NSOD is verified in the practical application, compared with empiric al formula in Chinese Regulations and in-situ test. These three methods were applied to determine the HOFZ of working face No. 111303 in No. 5 coal mine. The pre dicted HOFZ of NSOD is found to be similar to the result of the in-situ test (8.9% relative error), whereas the HOFZ calculated by the empirical formula has extremely large error (25.7% relative error). Results show that the NSOD can reliably predict the HOFZ in deep coal mining and reduce time and expenses required for in-situ test.
W trakcie prowadzenia wydobycia węgla w warstwie skalnej leżącej ponad zrobami powstaje strefa spękań. Jeśli nieciągłości te związane są z formacjami wodonośnymi, może nastąpić nagły wypływ wód do kopalni. Stąd też waga problemu i konieczność badania wysokości strefy spękań w warstwach nadkładu zalegających nad wyrobiskiem. W pracy tej główny nacisk położono na określenie wysokości strefy spękań warstwy nadkładu zalegającej ponad wyrobiskiem w kopalni podziemnej. W pierwszej części pracy przedstawiono główne charakterystyki powstawania deformacji i pęknięć w warstwach nadkładu. Następnie zaproponowano nową metodę symulacji numerycznych w układzie ortogonalnym i jej wykorzystanie do określania wysokości strefy spękań w warstwach nadkładu w kopalni podziemnej. Następnie powyższą metodę zweryfikowano w praktycznym zastosowaniu, jako poziomy odniesienia wykorzystano odpowiednie wzory empiryczne określone w przepisach obowiązujących w Chinach oraz wyniki pomiarów in-situ. Powyższe trzy metody zastosowane zostały do określenia wysokości strefy spękań w warstwach nadkładu przy prowadzeniu ściany 111303 w kopalni węgla nr 5. Wyniki obliczeń wysokości strefy spękań uzyskane w oparciu o zaproponowaną nową metodę w dużym stopniu pokrywały się z wynikami pomiarów in-situ (błąd względny 8.9%); podczas gdy obliczenia wysokości strefy spękań w oparciu o odpowiednie wzory empiryczne obarczone były dużym błędem (błąd względny 25.7%). Uzyskane wyniki wskazują wiarygodność obliczeń w oparciu o zaproponowaną metodę, co pozwoli na ograniczenie czasu i kosztów związanych z wykonywaniem pomiarów in-situ.
Źródło:
Archives of Mining Sciences; 2018, 63, 3; 617-631
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on one-dimensional ubiquitiformal constitutive relations for a bimaterial bar
Autorzy:
Yang, Min
Ou, Zhuo-Cheng
Duan, Zhuo-Ping
Huang, Feng-Lei
Powiązania:
https://bibliotekanauki.pl/articles/282073.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
ubiquitiform
fractal
composite
displacement distribution
elasticity modulus
Opis:
A one-dimensional ubiquitiformal constitutive model for a bimaterial bar is proposed in this paper. An explicit analytical expression for the effective Young modulus is then obtained, which, unlike the fractal one, leads to a continuous displacement distribution along the bar. Moreover, numerical results for concretes are calculated and found to be in agreement with previous experimental data. In addition, some previous empirical and semi-empirical constitutive models are also examined, which shows that each of these models can correspond well to a ubiquitiformal one under a certain complexity.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 2; 291-301
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Microstructure and Strengthening Mechanisms of Ti-6Cu-8Nb-xCr3C2 Alloy through Vacuum Sintering Process
Autorzy:
Chang, Shih-Hsien
Weng, Chen-Yu
Huang, Kuo-Tsung
Liang, Cheng
Powiązania:
https://bibliotekanauki.pl/articles/2106558.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vacuum sintering
Ti-6Cu-8Nb-Cr3C2 alloy
hardness
transverse rupture strength
EBSD
Opis:
This study mixes four different powders to produce Ti-6Cu-8Nb-xCr3C2 (x = 1, 3, and 5 mass%) alloys in three different proportions. The experimental results reveal that when 5 mass% Cr3C2 was added to the Ti-6Cu-8Nb alloys, the specimen possessed optimal mechanical properties after sintering at 1275°C for 1 h. The relative density reached 98.23%, hardness was enhanced to 67.8 HRA, and the transverse rupture strength (TRS) increased to 1821.2 MPa, respectively. The EBSD results show that the added Cr3C2 in situ decomposed into TiC and NbC during the sintering process, and the generated intermetallic compounds (Ti2Cu) were evenly dispersed in the Ti matrix. Furthermore, the reduced Cr atom acts as a β-phase stabilizing element and solid-solution in the Ti matrix. Consequently, the main strengthening mechanisms of the Ti-6Cu-8Nb-xCr3C2 alloys include dispersion strengthening, solid-solution strengthening, and precipitation hardening.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 3; 815--825
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the influence of the transducer and its coupling layer on round window stimulation
Autorzy:
Liu, H.
Xu, D.
Yang, J.
Yang, S.
Cheng, G.
Huang, X.
Powiązania:
https://bibliotekanauki.pl/articles/306655.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
słuch
stymulacja
przetwornik
RW
FEM
implantable middle ear hearing device
round window stimulation
transducer
coupling layer
finite element analysis
Opis:
Purpose: In this work, a finite element study is proposed to evaluate the effects of the transducer and its coupling layer on the performance of round window (RW) stimulation. Methods: Based on a set of micro-computer tomography images of a healthy adult’s right ear and reverse engineering technique, a coupled finite-element model of the human ear and the transducer was constructed and verified. Then, the effect of the cross-section of the transducer, the elastic modulus of the coupling layer, the mass of the transducer, and the preload of the transducer were studied. Results: The increase of the transducer’s cross-section area deteriorates the RW stimulation, especially at the lower frequencies. This adverse effect of the cross-section area’s increase of the transducer can be reduced by adding a coupling layer between the transducer and the RW. However, the coupling layer’s improvement on the RW stimulation is reduced with the increase of its elastic modulus. Moreover, the mass loading of the transducer decreases the RW stimulation’s performance mainly at higher frequencies and applying a static preload on the transducer enhances its hearing compensating performance at higher frequencies. Conclusions: The influence of the transducer’s mass, the mass of the transducer, the applied static preload and the properties of the coupling layer must be taken into account in the design of the RW stimulation type implantable middle ear hearing device.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 2; 103-111
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A stereological ubiquitiformal softening model for concrete
Autorzy:
Ou, Zhuo-Cheng
Li, Guan-Ying
Duan, Zhuo-Ping
Huang, Feng-Lei
Powiązania:
https://bibliotekanauki.pl/articles/281602.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
ubiquitiform
fractal
concrete
softening curve
Opis:
A stereological ubiquitiformal softening model for describing the softening behavior of concrete under quasi-static uniaxial tensile loadings is presented in this paper. In the model, both the damage evaluation process of fracture cross-sections and their distribution along the specimens axis are taken into account. The numerical results of a certain kind of full grade concrete made of crushed coarse aggregate are found to be in good agreement with the experimental data. Moreover, an experiental relation between the lower bound to the scale invariance of concrete and its tensile strength is also obtained by data fitting of the experimental data, which provides an effective approach to determine the lower bound to scale invariance of concrete.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 1; 27-35
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficient solidification of Pb2+ by activated tungsten tailings and cement
Autorzy:
Cheng, Hao
Kuang, Jingzhong
Zhu, Luping
Yuan, Weiquan
Huang, Zheyu
Yang, Yiqiang
Powiązania:
https://bibliotekanauki.pl/articles/24085840.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tungsten tailings
activation
Pb2+
Solidification
C-S-H gel
Opis:
The preparation of cementing admixture from tailings and co-solidification of Pb2+ with cement is a green way to realize the resource utilization of tailings and treatment of the lead-containing wastewater. In this paper, the tungsten tailings were activated in different ways, and the mechanical properties of the tungsten tailings-cement solidified body with different activation systems and the solidification behavior of Pb2+ were studied. The phase and microstructure of the hydrated product were characterized by XRD, FT-IR, SEM and EDS. The results showed that the curing effect of Pb2+ was obviously different of different activation systems, and the curing effect of the solidified body of the ternary composite activation system (TCAS) was the best, second only to the pure cement system (PCS). Different activation methods have a significant impact on the mechanical properties of the solidified body. With the increase of the Pb2+ content, the compressive strength of the solidified body gradually decreased, the Pb2+ leaching concentration gradually increased; with the extension of the curing age, the compressive strength gradually increased, and the Pb2+ leaching concentration gradually decreased. In particular, the compressive strength of the 28d solidified body was 31.43 MPa and the leaching concentration of Pb2+ was only 0.38 mg/L when the Pb2+ content was 5%. The phase, microstructure and EDS results of the hydration products showed that Pb2+ was mainly solidified in the C-S-H gel.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 2; art. no. 162618
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Fast Method of Feature Extraction for Lowering Vehicle Pass-By Noise Based on Nonnegative Tucker3 Decomposition
Autorzy:
Wang, H.
Cheng, G.
Deng, G.
Li, X.
Li, H.
Huang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/177883.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vehicle pass-by noise
NTD
feature extraction
sound pressure level
Opis:
Usually, the judgement of one type fault of vehicle pass-by noise is difficult for engineers, especially when some significant features are disturbed by other interference noise, such as the squealing noise is almost simultaneous with the whistle in the exhaust system. In order to cope with this problem, a new method, with the antinoise ability of the algorithm on the condition by which the features are entangled, is developed to extract clear features for the fault analysis. In the proposed method, the nonnegative Tucker3 decomposition (NTD) with fast updating algorithm, signed as NTD_FUP, can find out the natural frequency of the parts/components from the exhaust system. Not only does the NTD_FUP extract clear features from the confused noise, but also it is superior to the traditional methods in practice. Then, an aluminium-foil alloy material, which is used for the heat shield for its lower noise radiation, replaces the aluminium alloy alone. Extensive experiments show that the sound pressure level of the vehicle pass-by noise is reduced 0.9 dB(A) by the improved heat shield, which is also considered as a more lightweight design for the exhaust system of an automobile.
Źródło:
Archives of Acoustics; 2017, 42, 4; 619-629
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
System for Calibrating Analogue Merging Units in Absence of Synchronization Signals
Autorzy:
Cheng, H.-M.
Huang, Q.-F.
Ji, F.
Xu, Q.
Liu, J.
Tian, Z.
Powiązania:
https://bibliotekanauki.pl/articles/221084.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
intelligent substation
analogue merging unit
peer-to-peer communication
calibration system
synchronization signal
Opis:
Synchronization signals are requisite for calibrating electrical measurement devices with digital output when using conventional calibration methods. However, since the signal sampling process of the analogue merging units (MUs) operating in an intelligent substation does not rely on external synchronization signals, accuracy calibration without the use of synchronization signals is of particular importance in order to guarantee the measurement accuracy in practical situations. So far, very little research on calibration systems independent of synchronization signals has been performed. This paper presents a design of the calibration system without dependence on synchronization signals. To verify the feasibility of the proposed design, the designed system and a conventional calibration system have been employed in testing the accuracy of the same analogue MU of a 0.2 accuracy class. The comparison of the test results shows that the differences of ratio errors are below 0.02%, and the maximum difference of phase errors is about 4′. This paper also provides a new efficient and significant calibration method which does not require any external synchronization signals.
Źródło:
Metrology and Measurement Systems; 2018, 25, 1; 129-138
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the Mechanical and Thermal Properties, and Impact Sensitivity of Pressed HMX-based PBX
Autorzy:
Li, Yuxiang
Wu, Peng
Hua, Cheng
Wang, Jun
Huang, Bing
Chen, Jin
Qiao, Zhiqiang
Yang, Guangcheng
Powiązania:
https://bibliotekanauki.pl/articles/358006.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
nanoexplosives
impact sensitivity
particle size
hot spot
Opis:
Submicron- and nano-explosives have attracted growing attention, while the mechanism of how particle size influences the impact sensitivity is not completely understood. In the present work, HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) based PBXs (plastic bonded explosives) of three particle size distributions (1-2 and 10-20 μm, and 100-300 nm) and two pressed densities (91%TMD and 79%TMD) were characterized and tested with a range of techniques to determine their mechanical and thermal properties and impact sensitivities. The results demonstrated that with decreased particle size, the mechanical strength as well as the thermal conductivity were dramatically improved, and the impact sensitivity was significant decreased. The structure of impacted samples suggested that the ignition mechanism is dependant on the particle size. Samples with higher density were more sensitive to impact, as the impact force acting on these samples was higher. The correlation between particle size and impact sensitivity is discussed in detail.
Źródło:
Central European Journal of Energetic Materials; 2019, 16, 2; 295-315
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Impact Toughness of Offshore Steel
Autorzy:
Cheng, T.-C.
Yu, C.
Yang, T.-C.
Huang, C.-Y.
Lin, H.-C.
Shiue, R.-K.
Powiązania:
https://bibliotekanauki.pl/articles/351264.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low-temperature impact toughness
prior austenite grain size
hardenability
bainite
Opis:
This study focused on the effects of microstructures on the low-temperature impact toughness of directly water-quenched offshore steel. Martensite dominated the microstructure directly below the quenched surface. In contrast, mainly lower bainite, martensite, and low amount of ferrite were observed in the central region of the quenched specimen. The ductile to brittle transition temperature of tempered martensite was significantly lower than that of a bainite-dominated microstructure. It is found that low-angle boundaries within the bainite packets greatly impair the low-temperature impact toughness of the steel. The absence of high-angle boundaries in the lower bainite packets significantly deteriorates the low-temperature impact energy of offshore steel.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 1; 167-172
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy Metal Contamination of Surface Water and Groundwater in and Around Gejiu Tin Mine, Southwest China
Zanieczyszczenie wód powierzchniowych i podziemnych metalami ciężkimi w kopalni Gejiu Tin, południowo-zachodnie Chiny i jej okolicach
Autorzy:
Cheng, X.
Qi, W.
Danek, T.
Matysek, D.
Huang, Q.
Zhao, X.
Zhou, Z.
Fang, R.
Zou, L.
Xu, J.
Powiązania:
https://bibliotekanauki.pl/articles/317873.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
metale ciężkie
zanieczyszczenie
kopalnia cyny Gejiu
wody powierzchniowe
wody kopalniane
heavy metals
contamination
Gejiu tin mine
surface water
mine water
Opis:
Heavy metal contamination due to mining activity is a global major concern because of its potential health risks to local inhabitants. The heavy metal contamination of surface water and ground water by mining activities in Gejiu tin-polymetallic mining area, Southwest China, was studied. Surface water and ground water were sampled and analyzed using AAS for Cr6+, Cd, As, Hg, Cu, Pb, Zn, Se, Fe and Mn. Analysis of HCO3–, Cl–, SO42–, F– and NO3– in water samples was also undertaken by ion chromatography. It was shown that none of water samples exceeded the guideline of Cr6+, Se and Hg, while the contamination degree of heavy metals was Mn > Fe > Cd > Zn > Pb > As > Cu, all of which were serious contamination except mild contamination for Cu. The ground waters were polluted much worse than surface water.
Zanieczyszczenie metalami ciężkimi spowodowane działalnością kopalń jest światowym problemem z powodu ryzyka utraty zdrowia przez okolicznych mieszkańców. Zbadano zanieczyszczenie wód powierzchniowych oraz wód podziemnych wywołane działalnością kopalni cyny w rejonie górniczym Gejiu, południowo-zachodnie Chiny. Pobrano próbki wody powierzchniowej oraz podziemnej i zanalizowano je ze względu na obecność Cd, As, Hg, Cu, Pb, Zn, Se, Fe oraz Mn. Analizy HCO3–, Cl–, SO42–, F– oraz NO3– w próbkach wody również zostały przeprowadzone za pomocą chromatografii jonowej. Ukazano, że żadna z badanych wód nie przekroczyła dopuszczalnych poziomów dla Cr6+, Se oraz Hg. Jednakże poziom zanieczyszczenia metali ciężkimi tj. Mn > Fe > Cd > Zn > Pb > As > Cu był wysoki, za wyjątkiem niewielkiego przekroczenia norm dla Cu. Wody podziemne były znacznie bardziej zanieczyszczone niż wody powierzchniowe.
Źródło:
Inżynieria Mineralna; 2016, R. 17, nr 1, 1; 93-98
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł

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