In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in lran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consi...In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in lran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consisted ofCu, Ag, Pb and Se. Amount of Ag in the considered anode slime was 5.4% （by weight）. The goal was to recover as much as possible Ag from anode slime at atmospheric pressure to synthesize Ag nanoparticles. Therefore, acid leaching was used for this purpose. The anode slime was leached with sulfuric and nitric acid from room to 90 ~C at different acid concentrations and the run which yielded the most recovery of Ag was selected for Ag nanoparticles synthesis. At this condition, Cu, Pb and Se are lea- ched as well as Ag. To separate Ag from leach solution HCI was added and silver was precipitated as AgCl which were then dissolved by ammonia solution. The Ag nanoparticles are synthesized from this solution by chemical reduction method by aid of sodium borohydride in the presence of PVP and PEG as stabilizers. The synthesized Ag nanoparticles showed a peak of 394 nm in UV-vis spectrum and TEM images showed a rather uniform Ag nanoparticles of 12 nm.展开更多
Silver has grown its attraction of the scientists in microelectronic field recently.Electrochemical deposition of silver onto copper substrates by immersion method has been one of the keen topics. In this study, ethan...Silver has grown its attraction of the scientists in microelectronic field recently.Electrochemical deposition of silver onto copper substrates by immersion method has been one of the keen topics. In this study, ethanol was used as the plating solution in which some chemicals were added. The silver deposits were characterized by a field emission scanning electron microscopy （FESEM）, an atom force microscope （AFM）, a transmission electron microscope （TEM） and a selected area electron diffraction （SAED）. It was found that silver immersion using ethanol-based bath has good coverage feature. The highlands of the copper substrate are coated by silver particles whose sizes are around 12 nm, but those sizes at low-lying lands are a little smaller.展开更多
The intrinsic physical properties of the noble metal nanoparticles,which are highly sensitive to the nature of their local molecular environment,make such systems ideal for the detection of molecular recognition event...The intrinsic physical properties of the noble metal nanoparticles,which are highly sensitive to the nature of their local molecular environment,make such systems ideal for the detection of molecular recognition events.The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles.In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization.A brief discussion of the three common methods of functionalization:Electrostatic adsorption;Chemisorption;Affinity-based coordination is given.In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition.In the main section the various types of capping agents for molecular recognition;nucleic acid coatings,protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications.Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition.For the proteins the recognition properties of antibodies form the core of the section.With respect to the supramolecular systems the cyclodextrins,calix[n]arenes,dendrimers,crown ethers and the cucurbitales are treated in depth.Finally a short section deals with the possible toxicity of the nanoparticles,a concern in public health.展开更多
We report on the use of titanium dioxide nanoparticles (NPs) coated with poly-thiophene for the preconcentration of copper and silverions. The NPs were prepared by first modifying the surface of TiO2 NPs with vinyl gr...We report on the use of titanium dioxide nanoparticles (NPs) coated with poly-thiophene for the preconcentration of copper and silverions. The NPs were prepared by first modifying the surface of TiO2 NPs with vinyl groups and then copolymerizing them with vinyl thiophen. The resulting TiO2-polythiophene core-shell NPs were characterized by thermogravimetry, differential thermal analysis, scanning electron microscopy, Fourier transform infrared spectrometry and X-ray diffraction. The experimental conditions such as pH value, adsorption and desorption time, type, concentration and volume of the eluent, break through volume, and effect of potentially interfering ions were optimized. The ions were then desorbed with hydrochloric acid and determined by FAAS. The limits of detection are 0.4 and 1.2 μg·L_1 for Cu(II) and Ag(I), respectively, and recoveries and precisions are >98.0%展开更多
The association of gut microflora and human health is being increasingly recognized,and the impact of gut microflora on the host is well characterized,including the body’s energy metabolism and immune system maintena...The association of gut microflora and human health is being increasingly recognized,and the impact of gut microflora on the host is well characterized,including the body’s energy metabolism and immune system maintenance.Several human diseases,including metabolic,autoimmune,obesity,hypothyroidism,and intestinal disorders,are closely associated with gut dysbiosis.Inorganic nanoparticles(NPs)are extensively utilized in numerous fields due to their distinctive,attractive physicochemical properties.Estimation of the potential impacts of NPs,with a high number of microorganisms inside the human body(microbiota)and its genomes(microbiome),represents one of the most important aspects of nano-toxicology.This review article aims to provide information on the association of gut microflora alterations to diseases and describe the impacts of various inorganic NPs,including silver,zinc,selenium,titania,silicon,and copper,on gut microflora.Research on the effect of inorganic NPs on gut microflora of animal models and the poultry industry is reviewed.The response of pathogenic Enterobacter species to inorganic NPs has been expounded in detail.This review also highlights the need to focus on the ancillary effects of various inorganic NPs on gut microflora to expedite the suitable advancement of these particles for future use.Finally,the key opportunistic areas for the application of nanotechnology are underlined to manipulate the microbiome of gut dysbiosis,provide an overview,and address potential challenges and our perspective on this evolving field.展开更多
Two kinds of silver based medium temperature brazing filler metals(45AgCuZnSn and 60AgCuSn) were selected to braze and seal brass flange pipe and copper pipe by high frequency heating brazing. In this paper, the quali...Two kinds of silver based medium temperature brazing filler metals(45AgCuZnSn and 60AgCuSn) were selected to braze and seal brass flange pipe and copper pipe by high frequency heating brazing. In this paper, the quality of the braze was evaluated by immersion ultrasound, and the microstructure of the brazed joint was observed by SEM and EDS. The experimental results show that the high frequency heating brazing can quickly achieve the device sealing;through the ultrasonic flaw detection image calculation, the brazed bonding rate obtained by 60AgCuSn brazing is 87%, and by 45AgCuZnSn brazing is 71%;the cross-sectional area of the brazed joint obtained by two kinds of silver based medium temperature brazing filler metals is observed, the brazed joint obtained by 45AgCuZnSn brazing has defects visual, and a large amount of Zn element gathered in the defects, there is no obvious porosity in the brazed joint by 60AgCuSn brazing,and the bonding layer is dense and coherent. Through the contrast test, the choice of 60AgCuSn alloy brazing can meet the needs of high frequency brazing of brass flange pipe and copper pipe.展开更多
基金the International Center for Science, High Technology & Environmental Sciences for financial support of this work (No. 1.213)
文摘In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in lran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consisted ofCu, Ag, Pb and Se. Amount of Ag in the considered anode slime was 5.4% （by weight）. The goal was to recover as much as possible Ag from anode slime at atmospheric pressure to synthesize Ag nanoparticles. Therefore, acid leaching was used for this purpose. The anode slime was leached with sulfuric and nitric acid from room to 90 ~C at different acid concentrations and the run which yielded the most recovery of Ag was selected for Ag nanoparticles synthesis. At this condition, Cu, Pb and Se are lea- ched as well as Ag. To separate Ag from leach solution HCI was added and silver was precipitated as AgCl which were then dissolved by ammonia solution. The Ag nanoparticles are synthesized from this solution by chemical reduction method by aid of sodium borohydride in the presence of PVP and PEG as stabilizers. The synthesized Ag nanoparticles showed a peak of 394 nm in UV-vis spectrum and TEM images showed a rather uniform Ag nanoparticles of 12 nm.
基金Supported by the Key Project Foundation of Fujian Province (No. 200I011)
文摘Silver has grown its attraction of the scientists in microelectronic field recently.Electrochemical deposition of silver onto copper substrates by immersion method has been one of the keen topics. In this study, ethanol was used as the plating solution in which some chemicals were added. The silver deposits were characterized by a field emission scanning electron microscopy （FESEM）, an atom force microscope （AFM）, a transmission electron microscope （TEM） and a selected area electron diffraction （SAED）. It was found that silver immersion using ethanol-based bath has good coverage feature. The highlands of the copper substrate are coated by silver particles whose sizes are around 12 nm, but those sizes at low-lying lands are a little smaller.
文摘The intrinsic physical properties of the noble metal nanoparticles,which are highly sensitive to the nature of their local molecular environment,make such systems ideal for the detection of molecular recognition events.The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles.In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization.A brief discussion of the three common methods of functionalization:Electrostatic adsorption;Chemisorption;Affinity-based coordination is given.In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition.In the main section the various types of capping agents for molecular recognition;nucleic acid coatings,protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications.Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition.For the proteins the recognition properties of antibodies form the core of the section.With respect to the supramolecular systems the cyclodextrins,calix[n]arenes,dendrimers,crown ethers and the cucurbitales are treated in depth.Finally a short section deals with the possible toxicity of the nanoparticles,a concern in public health.
文摘We report on the use of titanium dioxide nanoparticles (NPs) coated with poly-thiophene for the preconcentration of copper and silverions. The NPs were prepared by first modifying the surface of TiO2 NPs with vinyl groups and then copolymerizing them with vinyl thiophen. The resulting TiO2-polythiophene core-shell NPs were characterized by thermogravimetry, differential thermal analysis, scanning electron microscopy, Fourier transform infrared spectrometry and X-ray diffraction. The experimental conditions such as pH value, adsorption and desorption time, type, concentration and volume of the eluent, break through volume, and effect of potentially interfering ions were optimized. The ions were then desorbed with hydrochloric acid and determined by FAAS. The limits of detection are 0.4 and 1.2 μg·L_1 for Cu(II) and Ag(I), respectively, and recoveries and precisions are >98.0%
文摘The association of gut microflora and human health is being increasingly recognized,and the impact of gut microflora on the host is well characterized,including the body’s energy metabolism and immune system maintenance.Several human diseases,including metabolic,autoimmune,obesity,hypothyroidism,and intestinal disorders,are closely associated with gut dysbiosis.Inorganic nanoparticles(NPs)are extensively utilized in numerous fields due to their distinctive,attractive physicochemical properties.Estimation of the potential impacts of NPs,with a high number of microorganisms inside the human body(microbiota)and its genomes(microbiome),represents one of the most important aspects of nano-toxicology.This review article aims to provide information on the association of gut microflora alterations to diseases and describe the impacts of various inorganic NPs,including silver,zinc,selenium,titania,silicon,and copper,on gut microflora.Research on the effect of inorganic NPs on gut microflora of animal models and the poultry industry is reviewed.The response of pathogenic Enterobacter species to inorganic NPs has been expounded in detail.This review also highlights the need to focus on the ancillary effects of various inorganic NPs on gut microflora to expedite the suitable advancement of these particles for future use.Finally,the key opportunistic areas for the application of nanotechnology are underlined to manipulate the microbiome of gut dysbiosis,provide an overview,and address potential challenges and our perspective on this evolving field.
基金supported by the National Key R&D Program of China(Grant No. 2017YFB0305702)。
文摘Two kinds of silver based medium temperature brazing filler metals(45AgCuZnSn and 60AgCuSn) were selected to braze and seal brass flange pipe and copper pipe by high frequency heating brazing. In this paper, the quality of the braze was evaluated by immersion ultrasound, and the microstructure of the brazed joint was observed by SEM and EDS. The experimental results show that the high frequency heating brazing can quickly achieve the device sealing;through the ultrasonic flaw detection image calculation, the brazed bonding rate obtained by 60AgCuSn brazing is 87%, and by 45AgCuZnSn brazing is 71%;the cross-sectional area of the brazed joint obtained by two kinds of silver based medium temperature brazing filler metals is observed, the brazed joint obtained by 45AgCuZnSn brazing has defects visual, and a large amount of Zn element gathered in the defects, there is no obvious porosity in the brazed joint by 60AgCuSn brazing,and the bonding layer is dense and coherent. Through the contrast test, the choice of 60AgCuSn alloy brazing can meet the needs of high frequency brazing of brass flange pipe and copper pipe.
