In this work,we report that the thermoelectric properties of Bi（0.52）Sb（1.48）Te3alloy can be enhanced by being composited with Mn Te nano particles（NPs）through a combined ball milling and spark plasma sintering...In this work,we report that the thermoelectric properties of Bi（0.52）Sb（1.48）Te3alloy can be enhanced by being composited with Mn Te nano particles（NPs）through a combined ball milling and spark plasma sintering（SPS）process.The addition of Mn Te into the host can synergistically reduce the lattice thermal conductivity by increasing the interface phononscattering between Bi（0.52）Sb（1.48）Te3 and MnTe NPs,and enhance the electrical transport properties by optimizing the hole concentration through partial Mn^2＋ acceptor doping on the Bi^3＋ sites of the host lattice.It is observed that the lattice thermal conductivity decreases with increasing the percentage of Mn Te and milling time in a temperature range from 300 Kto 500 K,which is consistent with the increasing of interfaces.Meanwhile,the bipolar effect is constrained to high temperatures,which results in the figure of merit z T peak shifting toward higher temperature and broadening the z T curves.The engineering z T is obtained to be 20%higher than that of the pristine sample for the 2-mol%Mn Te-added composite at a temperature gradient of 200 K when the cold end temperature is set to be 300 K.This result indicates that the thermoelectric performance of Bi0.52Sb1.48Te3 can be considerably enhanced by being composited with Mn Te NPs.展开更多
Nano-technology is expanding its horizon in various science and technology fields.In civil engineering,soil is a complex material and used for various functions and applications.Meanwhile,sometimes an effective soil s...Nano-technology is expanding its horizon in various science and technology fields.In civil engineering,soil is a complex material and used for various functions and applications.Meanwhile,sometimes an effective soil stabilization technique is needed to fulfil the site criteria and can be achieved by adopting various methods e.g.,physical,chemical,thermal or reinforcement using geotextiles and fabrics.The mechanism of soil stabilization using nanomaterials is still unexplored and open to prospective researchers.The present article attempts to touch and explore the possibilities of nano-technology in soil improvement and its applications in various civil engineering works.Microstructural analysis of the nanomaterials treated soils using the latest equipment has also been discussed.The study interprets that the use of nano materials is still limited,due to their high cost and sophisticated handling procedures.Though the use of nanoparticles in soil stabilization results in extraordinary improvements in various soil properties,the improved soil properties could be utilized for various geotechnical projects.The present study bridges the past findings to the present scenario of nanomaterials in soil improvement.展开更多
The nano-sized organic carbon （NOC） particles emitted from a small gasoline engine were characterized using various ex situ optical techniques to assess their hazardous impact. The exhaust gas was sampled iso-kineti...The nano-sized organic carbon （NOC） particles emitted from a small gasoline engine were characterized using various ex situ optical techniques to assess their hazardous impact. The exhaust gas was sampled iso-kinetically by a quartz probe and passed through de-ionized water to gather the hydrophilic car- bonaceous particulates as hydrosol. The hydrodynamic diameter of the particles ranged between 1.7 and 3.6 nm at no load, with a mean diameter of 2.4 nm. The particle size in the engine exhaust was found to increase at higher loads, which is attributed to coagulation of the particles. The chemical structure of the particles was analyzed using UV-vis and infra-red spectroscopy. Both the band gap energy and oscillator strength data evaluated from the UV-vis absorbance showed that the NOC particles contained polyaromatic hydrocarbon structures with three to five aromatic rings. Infra-red spectroscopy analysis further confirmed the presence of aliphatic and carbonyl functionalities in the aromatic structures of the particles. The fine size of the particles, their high number concentration for the type of the engine under study and their structural features, make the particles extremely hazardous for environment and health.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1601213 and 51472052)the Funds from Institute of Physics,Chinese Academy of Sciences
文摘In this work,we report that the thermoelectric properties of Bi（0.52）Sb（1.48）Te3alloy can be enhanced by being composited with Mn Te nano particles（NPs）through a combined ball milling and spark plasma sintering（SPS）process.The addition of Mn Te into the host can synergistically reduce the lattice thermal conductivity by increasing the interface phononscattering between Bi（0.52）Sb（1.48）Te3 and MnTe NPs,and enhance the electrical transport properties by optimizing the hole concentration through partial Mn^2＋ acceptor doping on the Bi^3＋ sites of the host lattice.It is observed that the lattice thermal conductivity decreases with increasing the percentage of Mn Te and milling time in a temperature range from 300 Kto 500 K,which is consistent with the increasing of interfaces.Meanwhile,the bipolar effect is constrained to high temperatures,which results in the figure of merit z T peak shifting toward higher temperature and broadening the z T curves.The engineering z T is obtained to be 20%higher than that of the pristine sample for the 2-mol%Mn Te-added composite at a temperature gradient of 200 K when the cold end temperature is set to be 300 K.This result indicates that the thermoelectric performance of Bi0.52Sb1.48Te3 can be considerably enhanced by being composited with Mn Te NPs.
文摘Nano-technology is expanding its horizon in various science and technology fields.In civil engineering,soil is a complex material and used for various functions and applications.Meanwhile,sometimes an effective soil stabilization technique is needed to fulfil the site criteria and can be achieved by adopting various methods e.g.,physical,chemical,thermal or reinforcement using geotextiles and fabrics.The mechanism of soil stabilization using nanomaterials is still unexplored and open to prospective researchers.The present article attempts to touch and explore the possibilities of nano-technology in soil improvement and its applications in various civil engineering works.Microstructural analysis of the nanomaterials treated soils using the latest equipment has also been discussed.The study interprets that the use of nano materials is still limited,due to their high cost and sophisticated handling procedures.Though the use of nanoparticles in soil stabilization results in extraordinary improvements in various soil properties,the improved soil properties could be utilized for various geotechnical projects.The present study bridges the past findings to the present scenario of nanomaterials in soil improvement.
基金the support from Council of Scientific and Industrial Research(CSIR),Govt.of India(Grant No.9/96(0622)2K10-EMR-I)for conducting this research
文摘The nano-sized organic carbon （NOC） particles emitted from a small gasoline engine were characterized using various ex situ optical techniques to assess their hazardous impact. The exhaust gas was sampled iso-kinetically by a quartz probe and passed through de-ionized water to gather the hydrophilic car- bonaceous particulates as hydrosol. The hydrodynamic diameter of the particles ranged between 1.7 and 3.6 nm at no load, with a mean diameter of 2.4 nm. The particle size in the engine exhaust was found to increase at higher loads, which is attributed to coagulation of the particles. The chemical structure of the particles was analyzed using UV-vis and infra-red spectroscopy. Both the band gap energy and oscillator strength data evaluated from the UV-vis absorbance showed that the NOC particles contained polyaromatic hydrocarbon structures with three to five aromatic rings. Infra-red spectroscopy analysis further confirmed the presence of aliphatic and carbonyl functionalities in the aromatic structures of the particles. The fine size of the particles, their high number concentration for the type of the engine under study and their structural features, make the particles extremely hazardous for environment and health.
