A novel three-dimension(3D)graphene/MgO composite was synthesized through self-assembly and embedding MgO nanoparticle in reduced graphene in situ.Fourier transform infrared(FT-IR)spectroscopy,thermal gravimetric anal...A novel three-dimension(3D)graphene/MgO composite was synthesized through self-assembly and embedding MgO nanoparticle in reduced graphene in situ.Fourier transform infrared(FT-IR)spectroscopy,thermal gravimetric analysis(TGA),scanning electron microscopy(SEM),transmission electron microscope(TEM),powder X-raydiffraction(XRD)and X-rayphotoelectron spectroscopy(XPS)were employed to characterize the prepared 3D graphene/MgO composite.The adsorption performance of some metal ions on 3D graphene/MgO was investigated.The results showed that the adsorption capacity was greater than 3D graphene and the maximum adsorption capacity at 25℃was found to be 358.96 mg/g,388.4 mg/g and 169.8 mg/g for Pb^2+,Cd^2+and Cu^2+,respectively.The adsorption kinetic conformed to the pseudo-second-order kinetic model and the adsorption isotherm was well described by Langmuir model.The thermodynamic constants revealed that the sorption process was endothermic and spontaneous in nature.Based on the results of the removal of heavy metal ions from metal smelting wastewater,it can be concluded that the prepared 3D graphene/MgO composite is an effective and potential adsorbent.展开更多
The single-walled carbon nanotube（SWNT） bundles and ropes have been prepared by using the anode are discharge plasma to evaporate the graphite rods which contain Fe, Co and Ni powders as catalyst in He atmosphere. M...The single-walled carbon nanotube（SWNT） bundles and ropes have been prepared by using the anode are discharge plasma to evaporate the graphite rods which contain Fe, Co and Ni powders as catalyst in He atmosphere. Many purifying methods are used for the products. It indicates that the synthesis of SWNTs has been greatly affected by the preparation parameters of catalyzer, the buffer gas and its pressure, the arc current intensity, etc. The optimal condition for preparing SWNTs in our case has been proposed. The forming mechanism of the SWNTs bundles and ropes is also studied qualitatively. The evaporated single graphite sheet tends to reduce its active energy.展开更多
In the present paper, we study effect of the long-range Coulomb interaction on the thermodynamic propertiesof graphene by renormalization group methods.Our calculations show that both the specific heat and the magneti...In the present paper, we study effect of the long-range Coulomb interaction on the thermodynamic propertiesof graphene by renormalization group methods.Our calculations show that both the specific heat and the magneticsusceptibility of the material behave differently from the Landau Fermi liquid.More precisely, we find that thesequantities are logarithmically suppressed with respect to its noninteracting counterpart when temperature is low.展开更多
Graphene(GR),a single‐layer carbon sheet with a hexagonal packed lattice structure,has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting prop...Graphene(GR),a single‐layer carbon sheet with a hexagonal packed lattice structure,has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting properties in enhancing light absorption,electron transfer dynamics,and surface reactions.Currently,numerous efforts have shown that the properties of GR,which are closely correlated to the photocatalytic performance of GR‐based composites are significantly affected by the synthesis methods.Herein,we first introduce the optimization strategies of GR‐based hybrids and then elaborate the synthesis of GR‐based composite photocatalysts oriented by manifold roles of GR in photoredox catalysis,containing photoelectron mediator and acceptor,improving adsorption capacity,regulating light absorption range and intensity,as well as macromolecular photosensitizer.Beyond that,a brief outlook on the challenges in this burgeoning research field and potential evolution strategies for enhancing the photoactivity of GR‐based hybrids is presented and we anticipate that this review could provide some enlightenments for the rational construction and application of multifunctional GR‐based composite photocatalysts.展开更多
Research was done with the objective of evaluating the quality of water supplied to the potable water system in Hidalgo Del Parral, which comes from two main supply sources： wells from ＂Valle del Verano＂, which pro...Research was done with the objective of evaluating the quality of water supplied to the potable water system in Hidalgo Del Parral, which comes from two main supply sources： wells from ＂Valle del Verano＂, which provide water to the east side of the city, and the Water Treatment Plant, which receives water from different mines and supplies the west side of the city. When this plant is overcome on its capacity of treatment, a part of the water from the mines is fed directly to the northwest part of the city. The metals lead （Pb）, chromium （Cr）, cadmium （Cd）, zinc （Zn）, and arsenic （As） were analyzed by atomic absorption （AA） technique, based on the United States Environmental Protection Agency （EPA） Method 7000B （Revision 2, February 2007）. The digestion process was done according to the guidelines established in Method NMX-AA-051-SCFI-2001, Analysis of Water-Determination of Metals by Atomic Absorption, developed by the National Standardization Technical Committee for Environmental Protection （Mexico）. The samples were collected from the following points： 13 wells and 2 re-pumping stations of ＂Valle del Verano＂, the inlet and outlet of the Water Treatment Plant, and domestic faucets. The east side of the city, supplied by the wells of ＂Valle del Verano＂, is metal-pollution free. The water that comes from the mines contains high concentrations of As, Zn, Cd and Pb, with levels that can get to 0.12, 32.6, 0.26 and 3.5 mg/L, respectively. This water pollution generated by mining can be concluded from the high levels found in the domestic samples in which, for several points, the concentrations exceed the parameters set by the current guideline. According to the results, it is vital to set a plan of remediation for the water that comes from the mines, because there is a great risk for health in the consumotion of this water.展开更多
Our contribution analyzes the process of convergence with the International Standards of Audit （ISAs）, particularly those that regulate the concept of materiality in Mexico and Colombia. Between other results, acros...Our contribution analyzes the process of convergence with the International Standards of Audit （ISAs）, particularly those that regulate the concept of materiality in Mexico and Colombia. Between other results, across a survey, it is demonstrated why the effective use of the factors that emerge of his qualitative slope can favor the quality of the financial information that publish the audited companies, the usefulness and the comprehensibility of the report of opinion. In general, the reliability, transparency, and relevancy of the financial statements will meet potentially favored with the strict application of these major and better normative instruments.展开更多
The present work was undertaken in a cattle ranch of the north of Puebla state, Mexico. The aim was to incorporate Guazuma leaves （Guazuma ulmifolia） in the diet of growing calves and evaluate its effect on weight g...The present work was undertaken in a cattle ranch of the north of Puebla state, Mexico. The aim was to incorporate Guazuma leaves （Guazuma ulmifolia） in the diet of growing calves and evaluate its effect on weight gain. Twenty-four Cebu × Swiss calves （approximately live weight 250 kg） were used during all the experimental period （64 d）. They were assigned to a completely randomized design under two treatments （n = 12 for each treatment）： control （T1） consisted of commercial feed based on 15% crude protein （CP） ＋ cut Taiwan grass and the treatment （T2） consisted of a formulated diet containing 14.7% CP including Guazuma. The composition of the formulated diet consisted of： Guazuma （60%）, rolled corn （12%）, ground sorghum （9%）, oats in grain （7%）, wheat bran （9%） and vitamins and minerals. The feed was offered twice a day at a rate of 3% of live weight for 64 d. The mean daily gain for T1 and T2 was 1.15 g/animal and 1.52 g/animal, respectively （p 〈 0.05）. Results indicate that Guazuma-based supplements resulted in greater productive yield in growing calves.展开更多
基金Projects(21571191,51674292) supported by the National Natural Science Foundation of ChinaProject(2016JJ1023) supported by the Natural Science Foundation of Hunan Province,ChinaProject(2018TP1003) supported by the Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety,China
文摘A novel three-dimension(3D)graphene/MgO composite was synthesized through self-assembly and embedding MgO nanoparticle in reduced graphene in situ.Fourier transform infrared(FT-IR)spectroscopy,thermal gravimetric analysis(TGA),scanning electron microscopy(SEM),transmission electron microscope(TEM),powder X-raydiffraction(XRD)and X-rayphotoelectron spectroscopy(XPS)were employed to characterize the prepared 3D graphene/MgO composite.The adsorption performance of some metal ions on 3D graphene/MgO was investigated.The results showed that the adsorption capacity was greater than 3D graphene and the maximum adsorption capacity at 25℃was found to be 358.96 mg/g,388.4 mg/g and 169.8 mg/g for Pb^2+,Cd^2+and Cu^2+,respectively.The adsorption kinetic conformed to the pseudo-second-order kinetic model and the adsorption isotherm was well described by Langmuir model.The thermodynamic constants revealed that the sorption process was endothermic and spontaneous in nature.Based on the results of the removal of heavy metal ions from metal smelting wastewater,it can be concluded that the prepared 3D graphene/MgO composite is an effective and potential adsorbent.
文摘The single-walled carbon nanotube（SWNT） bundles and ropes have been prepared by using the anode are discharge plasma to evaporate the graphite rods which contain Fe, Co and Ni powders as catalyst in He atmosphere. Many purifying methods are used for the products. It indicates that the synthesis of SWNTs has been greatly affected by the preparation parameters of catalyzer, the buffer gas and its pressure, the arc current intensity, etc. The optimal condition for preparing SWNTs in our case has been proposed. The forming mechanism of the SWNTs bundles and ropes is also studied qualitatively. The evaporated single graphite sheet tends to reduce its active energy.
基金Supported by the Chinese National Science Foundation under Grant No.10874003 by Ministry of Science and Technology of China under Grant No.2006CB921300
文摘In the present paper, we study effect of the long-range Coulomb interaction on the thermodynamic propertiesof graphene by renormalization group methods.Our calculations show that both the specific heat and the magneticsusceptibility of the material behave differently from the Landau Fermi liquid.More precisely, we find that thesequantities are logarithmically suppressed with respect to its noninteracting counterpart when temperature is low.
文摘Graphene(GR),a single‐layer carbon sheet with a hexagonal packed lattice structure,has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting properties in enhancing light absorption,electron transfer dynamics,and surface reactions.Currently,numerous efforts have shown that the properties of GR,which are closely correlated to the photocatalytic performance of GR‐based composites are significantly affected by the synthesis methods.Herein,we first introduce the optimization strategies of GR‐based hybrids and then elaborate the synthesis of GR‐based composite photocatalysts oriented by manifold roles of GR in photoredox catalysis,containing photoelectron mediator and acceptor,improving adsorption capacity,regulating light absorption range and intensity,as well as macromolecular photosensitizer.Beyond that,a brief outlook on the challenges in this burgeoning research field and potential evolution strategies for enhancing the photoactivity of GR‐based hybrids is presented and we anticipate that this review could provide some enlightenments for the rational construction and application of multifunctional GR‐based composite photocatalysts.
文摘Research was done with the objective of evaluating the quality of water supplied to the potable water system in Hidalgo Del Parral, which comes from two main supply sources： wells from ＂Valle del Verano＂, which provide water to the east side of the city, and the Water Treatment Plant, which receives water from different mines and supplies the west side of the city. When this plant is overcome on its capacity of treatment, a part of the water from the mines is fed directly to the northwest part of the city. The metals lead （Pb）, chromium （Cr）, cadmium （Cd）, zinc （Zn）, and arsenic （As） were analyzed by atomic absorption （AA） technique, based on the United States Environmental Protection Agency （EPA） Method 7000B （Revision 2, February 2007）. The digestion process was done according to the guidelines established in Method NMX-AA-051-SCFI-2001, Analysis of Water-Determination of Metals by Atomic Absorption, developed by the National Standardization Technical Committee for Environmental Protection （Mexico）. The samples were collected from the following points： 13 wells and 2 re-pumping stations of ＂Valle del Verano＂, the inlet and outlet of the Water Treatment Plant, and domestic faucets. The east side of the city, supplied by the wells of ＂Valle del Verano＂, is metal-pollution free. The water that comes from the mines contains high concentrations of As, Zn, Cd and Pb, with levels that can get to 0.12, 32.6, 0.26 and 3.5 mg/L, respectively. This water pollution generated by mining can be concluded from the high levels found in the domestic samples in which, for several points, the concentrations exceed the parameters set by the current guideline. According to the results, it is vital to set a plan of remediation for the water that comes from the mines, because there is a great risk for health in the consumotion of this water.
文摘Our contribution analyzes the process of convergence with the International Standards of Audit （ISAs）, particularly those that regulate the concept of materiality in Mexico and Colombia. Between other results, across a survey, it is demonstrated why the effective use of the factors that emerge of his qualitative slope can favor the quality of the financial information that publish the audited companies, the usefulness and the comprehensibility of the report of opinion. In general, the reliability, transparency, and relevancy of the financial statements will meet potentially favored with the strict application of these major and better normative instruments.
文摘The present work was undertaken in a cattle ranch of the north of Puebla state, Mexico. The aim was to incorporate Guazuma leaves （Guazuma ulmifolia） in the diet of growing calves and evaluate its effect on weight gain. Twenty-four Cebu × Swiss calves （approximately live weight 250 kg） were used during all the experimental period （64 d）. They were assigned to a completely randomized design under two treatments （n = 12 for each treatment）： control （T1） consisted of commercial feed based on 15% crude protein （CP） ＋ cut Taiwan grass and the treatment （T2） consisted of a formulated diet containing 14.7% CP including Guazuma. The composition of the formulated diet consisted of： Guazuma （60%）, rolled corn （12%）, ground sorghum （9%）, oats in grain （7%）, wheat bran （9%） and vitamins and minerals. The feed was offered twice a day at a rate of 3% of live weight for 64 d. The mean daily gain for T1 and T2 was 1.15 g/animal and 1.52 g/animal, respectively （p 〈 0.05）. Results indicate that Guazuma-based supplements resulted in greater productive yield in growing calves.
