The causes of tiny spot defects on the surface of hot-dip galvanized automotive steel sheets were studied using scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS),and effective control measures w...The causes of tiny spot defects on the surface of hot-dip galvanized automotive steel sheets were studied using scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS),and effective control measures were introduced.The results show that rubbing against the top roller after galvanizing is easy due to the local thickness of tiny spot defect location coating;therefore,the surface morphology is different from the normal part.Three kinds of defects,namely zinc slag,small slivers,and pitting,are likely to cause local thickening of the coating after galvanizing,leading to the formation of tiny spots.Therefore,resolving the three types of defects can effectively control the generation of tiny spot defects.Among them,due to the hereditary nature of the small sliver defect,focusing on its control and supervision is necessary.展开更多
The aim of this work is to inventory and study the lignicolous parasitic macrofungi of the Tin plant formation. The mycological outings from July to September 2018 and 2019, collected forty-four (44) basidiomes throug...The aim of this work is to inventory and study the lignicolous parasitic macrofungi of the Tin plant formation. The mycological outings from July to September 2018 and 2019, collected forty-four (44) basidiomes through a random sampling device over an area of 40,000 m2 including 1000 m long by 40 m2 wide. The standard methods and techniques used in mycology for taxonomic studies were used to describe and classify the carpophores collected in three families: Hymenochaetaceae, Ganodermataceae and Polyporaceae, into eight genera: Onnia (4.55%), Amauroderma (4.55%), Ganoderma (20.45%), Phellinus (52.27%), Inonotus (4.55%), Phellinopsis (6.82%), Grammothele (2.27%) and Trametes (4.55%). The genera Phellinus and Ganoderma were the most abundant. Finally, eight species were identified: Inonotus cf. ochroporus, Inonotus cf. pachyphloeus, Phellinus cf. cryptarum, Phellinus cf. hartigii, Phellinus cf. hippophaecola;Phellinus cf. robustus, Phellinus cf. igniarius, et Amauroderma cf. fasciculatum. Seven fungal species belong to the family Hymenochaetaceae and only the species Amauroderma cf. fasciculatum is a Ganodermataceae. However, all these fungal species are shown to be parasites of trunks and/or branches of the following woody: Parkia biglobosa (50%), Anogeissus leiocarpus (25%), Annona senegalensis (12.5%) and Mangifera indica (12.5%). Authors attest that the presence of phytoparasitic polypores in a plant formation is an indicator of aging hence the urgency to put in place the appropriate measures to safeguard and restore Tin’s plant formation.展开更多
The aim of this study of the spatial dispersion of tin, niobium and tantalum mineralization associated with the Mayo Darlé granitoids was to produce prospecting guides through predictive maps of Sn, Nb and Ta in ...The aim of this study of the spatial dispersion of tin, niobium and tantalum mineralization associated with the Mayo Darlé granitoids was to produce prospecting guides through predictive maps of Sn, Nb and Ta in the region. It was based on a database (in appendix) obtained after analysis of rock samples (greisens and quartz veins) collected in the field, using a portable X-ray fluorescence (XRF) spectrometer. Two approaches were used: 1) structural studies in the field using the directions of veins and fractures 2) the use of variographic maps, an essential element in geostatistics for determining directional anisotropies. A joint synthesis of the modelling results shows that tin, tantalum and niobium mineralization at Mayo Darlé is concentrated along strike intervals N315E to N320E, with mineralization also occurring along strike N35E for high-grade Sn, medium-grade Ta and low-grade Nb. In short, mineral concentrations disperse progressively in space: positively from east to west for tantalum and niobium, and inversely for tin.展开更多
Perovskites are a category of materials with a unique crystal structure that allows them to absorb sunlight efficiently. This efficiency is particularly high in the case of CH<sub>3</sub>NH<sub>3<...Perovskites are a category of materials with a unique crystal structure that allows them to absorb sunlight efficiently. This efficiency is particularly high in the case of CH<sub>3</sub>NH<sub>3</sub>Pb<sub>1-x</sub>Sn<sub>x</sub>I<sub>3</sub> mixed perovskites. The combination of lead (Pb) and tin (Sn) in this matrix provides a broad spectrum of sunlight absorption, enabling the generation of a larger voltage and, subsequently, increased power. The primary objective in solar cell development is to maximize the conversion of sunlight into electricity. Mixed perovskites like CH<sub>3</sub>NH<sub>3</sub>Pb<sub>1-x</sub>Sn<sub>x</sub>I<sub>3</sub> have demonstrated significant potential in this regard. Their tunable bandgap, courtesy of varying the Pb: Sn ratio, allows for the optimization of sunlight absorption. The result is solar cells that surpass many conventional counterparts in terms of energy efficiency. Another significant advantage of these mixed perovskite solar cells is their cost-effectiveness. They can be manufactured using solution-based processes, which are less expensive than the high-vacuum methods required for traditional silicon solar cells. While the prospects for mixed perovskite solar cells are undeniably promising, there are concerns about the toxicity of lead, a key component of these cells. Lead is known to have harmful effects on the environment and health. The aim of our work is to reduce or eliminate lead toxicity in the perovskite cell while maintaining its efficiency. Thus, in a theoretical and experimental approach, we obtained following efficiencies of samples: CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> (22.49%) CH<sub>3</sub>NH<sub>3</sub>Pb<sub>0.75</sub>Sn<sub>0.25</sub>I<sub>3</sub> (22.72%), CH<sub>3</sub>NH<sub>3</sub>Pb<sub>0.5</sub>Sn<sub>0.5</sub>I<sub>3</sub> (23.00%) CH<sub>3</sub>NH<sub>3</sub>Pb<sub>0.25</sub>Sn<sub>0.75</sub>I<sub>3</sub> (22.61%), CH<sub>3</sub>NH<sub>3</sub>SnI<sub>3</sub> (22.38%). Doping with 50% tin gives the highest result (23.00%). By replacing a fraction of the lead with tin, the research aims to reduce the environmental footprint of the cells while maintaining their high performance. However, the challenge is to achieve a balance that does not compromise performance while reducing toxicity. .展开更多
Hot-dip coating has been practically employed in manufacturing zinc alloy coated steel sheets.However,it is difficult to coat aluminum alloy on a bulky steel substrate without sufficient preheating,because a rapidly s...Hot-dip coating has been practically employed in manufacturing zinc alloy coated steel sheets.However,it is difficult to coat aluminum alloy on a bulky steel substrate without sufficient preheating,because a rapidly solidified layer containing gas babbles is formed on a substrate surface.A variety of iron-aluminides are also formed at the interface of a steel and aluminum hot-dip coating system,which is the main difficulty in joining of steel with aluminum.Ultrasonic vibration was applied to a steel substrate during hot-dip coating of aluminum alloy to control a rapidly solidified layer and a brittle reaction layer.Hot dipping of columnar steel substrates into molten aluminum alloy (Al-2.7 mass fraction Si-4.6 mass fraction Sn) was carried out through the use of a Langevin oscillator with resonant frequency of 19.5 kHz.The application of ultrasonic vibration is quite effective to control a rapidly solidified layer and a surface oxide layer from a substrate surface by the sonocapillary effect based on a cavitation phenomenon,so that the intimate contact is achieved at the beginning of hot-dip coating.The application of ultrasonic vibration to hot-dipping is effective to control a reaction layer with less than 5 #m in thickness.An impact test exhibits that the good adhesive strength is approved in hot-dipped aluminum coatings with a thin reaction layer of approximately 5μm.展开更多
文摘The causes of tiny spot defects on the surface of hot-dip galvanized automotive steel sheets were studied using scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS),and effective control measures were introduced.The results show that rubbing against the top roller after galvanizing is easy due to the local thickness of tiny spot defect location coating;therefore,the surface morphology is different from the normal part.Three kinds of defects,namely zinc slag,small slivers,and pitting,are likely to cause local thickening of the coating after galvanizing,leading to the formation of tiny spots.Therefore,resolving the three types of defects can effectively control the generation of tiny spot defects.Among them,due to the hereditary nature of the small sliver defect,focusing on its control and supervision is necessary.
文摘The aim of this work is to inventory and study the lignicolous parasitic macrofungi of the Tin plant formation. The mycological outings from July to September 2018 and 2019, collected forty-four (44) basidiomes through a random sampling device over an area of 40,000 m2 including 1000 m long by 40 m2 wide. The standard methods and techniques used in mycology for taxonomic studies were used to describe and classify the carpophores collected in three families: Hymenochaetaceae, Ganodermataceae and Polyporaceae, into eight genera: Onnia (4.55%), Amauroderma (4.55%), Ganoderma (20.45%), Phellinus (52.27%), Inonotus (4.55%), Phellinopsis (6.82%), Grammothele (2.27%) and Trametes (4.55%). The genera Phellinus and Ganoderma were the most abundant. Finally, eight species were identified: Inonotus cf. ochroporus, Inonotus cf. pachyphloeus, Phellinus cf. cryptarum, Phellinus cf. hartigii, Phellinus cf. hippophaecola;Phellinus cf. robustus, Phellinus cf. igniarius, et Amauroderma cf. fasciculatum. Seven fungal species belong to the family Hymenochaetaceae and only the species Amauroderma cf. fasciculatum is a Ganodermataceae. However, all these fungal species are shown to be parasites of trunks and/or branches of the following woody: Parkia biglobosa (50%), Anogeissus leiocarpus (25%), Annona senegalensis (12.5%) and Mangifera indica (12.5%). Authors attest that the presence of phytoparasitic polypores in a plant formation is an indicator of aging hence the urgency to put in place the appropriate measures to safeguard and restore Tin’s plant formation.
文摘The aim of this study of the spatial dispersion of tin, niobium and tantalum mineralization associated with the Mayo Darlé granitoids was to produce prospecting guides through predictive maps of Sn, Nb and Ta in the region. It was based on a database (in appendix) obtained after analysis of rock samples (greisens and quartz veins) collected in the field, using a portable X-ray fluorescence (XRF) spectrometer. Two approaches were used: 1) structural studies in the field using the directions of veins and fractures 2) the use of variographic maps, an essential element in geostatistics for determining directional anisotropies. A joint synthesis of the modelling results shows that tin, tantalum and niobium mineralization at Mayo Darlé is concentrated along strike intervals N315E to N320E, with mineralization also occurring along strike N35E for high-grade Sn, medium-grade Ta and low-grade Nb. In short, mineral concentrations disperse progressively in space: positively from east to west for tantalum and niobium, and inversely for tin.
文摘Perovskites are a category of materials with a unique crystal structure that allows them to absorb sunlight efficiently. This efficiency is particularly high in the case of CH<sub>3</sub>NH<sub>3</sub>Pb<sub>1-x</sub>Sn<sub>x</sub>I<sub>3</sub> mixed perovskites. The combination of lead (Pb) and tin (Sn) in this matrix provides a broad spectrum of sunlight absorption, enabling the generation of a larger voltage and, subsequently, increased power. The primary objective in solar cell development is to maximize the conversion of sunlight into electricity. Mixed perovskites like CH<sub>3</sub>NH<sub>3</sub>Pb<sub>1-x</sub>Sn<sub>x</sub>I<sub>3</sub> have demonstrated significant potential in this regard. Their tunable bandgap, courtesy of varying the Pb: Sn ratio, allows for the optimization of sunlight absorption. The result is solar cells that surpass many conventional counterparts in terms of energy efficiency. Another significant advantage of these mixed perovskite solar cells is their cost-effectiveness. They can be manufactured using solution-based processes, which are less expensive than the high-vacuum methods required for traditional silicon solar cells. While the prospects for mixed perovskite solar cells are undeniably promising, there are concerns about the toxicity of lead, a key component of these cells. Lead is known to have harmful effects on the environment and health. The aim of our work is to reduce or eliminate lead toxicity in the perovskite cell while maintaining its efficiency. Thus, in a theoretical and experimental approach, we obtained following efficiencies of samples: CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> (22.49%) CH<sub>3</sub>NH<sub>3</sub>Pb<sub>0.75</sub>Sn<sub>0.25</sub>I<sub>3</sub> (22.72%), CH<sub>3</sub>NH<sub>3</sub>Pb<sub>0.5</sub>Sn<sub>0.5</sub>I<sub>3</sub> (23.00%) CH<sub>3</sub>NH<sub>3</sub>Pb<sub>0.25</sub>Sn<sub>0.75</sub>I<sub>3</sub> (22.61%), CH<sub>3</sub>NH<sub>3</sub>SnI<sub>3</sub> (22.38%). Doping with 50% tin gives the highest result (23.00%). By replacing a fraction of the lead with tin, the research aims to reduce the environmental footprint of the cells while maintaining their high performance. However, the challenge is to achieve a balance that does not compromise performance while reducing toxicity. .
文摘Hot-dip coating has been practically employed in manufacturing zinc alloy coated steel sheets.However,it is difficult to coat aluminum alloy on a bulky steel substrate without sufficient preheating,because a rapidly solidified layer containing gas babbles is formed on a substrate surface.A variety of iron-aluminides are also formed at the interface of a steel and aluminum hot-dip coating system,which is the main difficulty in joining of steel with aluminum.Ultrasonic vibration was applied to a steel substrate during hot-dip coating of aluminum alloy to control a rapidly solidified layer and a brittle reaction layer.Hot dipping of columnar steel substrates into molten aluminum alloy (Al-2.7 mass fraction Si-4.6 mass fraction Sn) was carried out through the use of a Langevin oscillator with resonant frequency of 19.5 kHz.The application of ultrasonic vibration is quite effective to control a rapidly solidified layer and a surface oxide layer from a substrate surface by the sonocapillary effect based on a cavitation phenomenon,so that the intimate contact is achieved at the beginning of hot-dip coating.The application of ultrasonic vibration to hot-dipping is effective to control a reaction layer with less than 5 #m in thickness.An impact test exhibits that the good adhesive strength is approved in hot-dipped aluminum coatings with a thin reaction layer of approximately 5μm.