日前，美国桑迪亚国家实验室（Sandia National Laboratories，USA）的研究人员成功开发出一种合成二氧化钛纳米牡子的新方法，该工艺成本低康。有着良好的应用前最。二氧化钛纳米粒子作为光封裟材料的填料，用于LED、太阳能电池等光电...日前，美国桑迪亚国家实验室（Sandia National Laboratories，USA）的研究人员成功开发出一种合成二氧化钛纳米牡子的新方法，该工艺成本低康。有着良好的应用前最。二氧化钛纳米粒子作为光封裟材料的填料，用于LED、太阳能电池等光电器件上，可有效提高产品的折射率，但是由于传统工艺制备二氧化钛纳米粒子具有技术复杂、价格昂贵等缺点，导致该产品在上述领域的应用受到极大制约。桑迪亚国宦实验室的研究人员采用廉价易得的酒精作为溶剂，通过控制工艺条件得到理想的产品。所碍二氧化钛产品的粒径为5nm，约是可见光波长的1／100，几乎不存在光的散射，从而可提高光封装材料的透光度和折射率。目前该实验室正寻求商业合作伙伴，以推动该技术的市场化进程。展开更多
We investigated the photovoltaic properties of series of TiO 2 photocatalysts by means of SPS and found that the thresholds of TiO 2 particles blue shift with their particle sizes decreasing and crystal phases changin...We investigated the photovoltaic properties of series of TiO 2 photocatalysts by means of SPS and found that the thresholds of TiO 2 particles blue shift with their particle sizes decreasing and crystal phases changing from rutile TiO 2 to anatase TiO 2. Combining with the photodegradation activities of TiO 2 on C 7H 16 , it was concluded that the photocatalytic activities of TiO 2 increase with their thresholds increasing,which can be explained using energy band theory. We also investigated the relationship beween the photovoltaic properties and photocatalytic activities of B TiO 2 before and after photooxidation on C 7H 16 , SO 2 and C 7H 16 +SO 2, respectively and found adsorbates at the surface of TiO 2 affect their photocatalytic activities and conduction types of surface layer.展开更多
By varying the hydrolysis and hydrothermal processing parameters in preparing TiO2 nanoparticles different sizes of TiO2 nanoparticles are obtained.(1) At higher autoclaving temperature,lower pH and longer autoclaving...By varying the hydrolysis and hydrothermal processing parameters in preparing TiO2 nanoparticles different sizes of TiO2 nanoparticles are obtained.(1) At higher autoclaving temperature,lower pH and longer autoclaving period,larger sizes of TiO2 nanoparticles are prepared.(2) The nanoporous electrodes made from sintering smaller TiO2 nanoparticles show relatively poor IPCE and low absorption in UV-Vis spectrum,(3) Higher IPCE can be achieved with TiO2 nanoporous electrodes made from sintering larger TiO2 nanoparticles.These electrodes are suitable for studying behavior of the photoelectrochemistry of dye sensitized nanoporous electrodes.展开更多
TiO2 semiconductive nanoparticles are added into mineral and ester based transformer oil to form semiconductive nanofluids (SNFs) with the aim of enhancing the oil’s insulating performance. Charge accumulation and de...TiO2 semiconductive nanoparticles are added into mineral and ester based transformer oil to form semiconductive nanofluids (SNFs) with the aim of enhancing the oil’s insulating performance. Charge accumulation and decay characteristics of both pure oils and SNFs are measured by pulse electroacoustic (PEA) technique. The result reveals that compared with pure oil, SNFs have more uniform in- ternal electric fields with voltage applied and higher charge decay rate after removing the applied voltage. This is caused by the increase of shallow trap density in SNFs, due to the test results of thermally stimulated current (TSC). It is proposed that the electron trapping and de-trapping processes in shallow traps could be the main charge transport processes in the nanofluid transformer oil.展开更多
In order to investigate the mechanism of nanoparticles enhancing the heat and mass transfer of the ammonia-water absorption process,several types of binary nanofluids were prepared by mixing Al2O3 nanoparticles with p...In order to investigate the mechanism of nanoparticles enhancing the heat and mass transfer of the ammonia-water absorption process,several types of binary nanofluids were prepared by mixing Al2O3 nanoparticles with polyacrylic acid(PAA),TiO2 with polyethylene glycol(PEG 1000),and TiN,SiC,hydroxyapatite(noodle-like) with PEG 10000 to ammonia-water solution,respectively.The thermal conductivities were measured by using a KD2 Pro thermal properties analyzer.The influences of surfactant and ammonia on the dispersion stabilities of the binary nanofluids were investigated by the light absorbency ratio index methods.The results show that the type,content and size of nanoparticles,the temperature as well as the dispersion stability are the key parameters that affect the thermal conductivity of nanofluids.For the given nanoparticle material and the base fluid,the thermal conductivity ratio of the nanofluid to the ammonia-water liquid increases as the nanoparticle content and the temperature are increased,and the diameter of nanoparticle is decreased.Furthermore,the thermal conductivity ratio increases significantly by improving the stabilities of nanofluids,which is achieved by adding surfactants or performing the proper ammonia content in the fluid.展开更多
文摘日前，美国桑迪亚国家实验室（Sandia National Laboratories，USA）的研究人员成功开发出一种合成二氧化钛纳米牡子的新方法，该工艺成本低康。有着良好的应用前最。二氧化钛纳米粒子作为光封裟材料的填料，用于LED、太阳能电池等光电器件上，可有效提高产品的折射率，但是由于传统工艺制备二氧化钛纳米粒子具有技术复杂、价格昂贵等缺点，导致该产品在上述领域的应用受到极大制约。桑迪亚国宦实验室的研究人员采用廉价易得的酒精作为溶剂，通过控制工艺条件得到理想的产品。所碍二氧化钛产品的粒径为5nm，约是可见光波长的1／100，几乎不存在光的散射，从而可提高光封装材料的透光度和折射率。目前该实验室正寻求商业合作伙伴，以推动该技术的市场化进程。
文摘We investigated the photovoltaic properties of series of TiO 2 photocatalysts by means of SPS and found that the thresholds of TiO 2 particles blue shift with their particle sizes decreasing and crystal phases changing from rutile TiO 2 to anatase TiO 2. Combining with the photodegradation activities of TiO 2 on C 7H 16 , it was concluded that the photocatalytic activities of TiO 2 increase with their thresholds increasing,which can be explained using energy band theory. We also investigated the relationship beween the photovoltaic properties and photocatalytic activities of B TiO 2 before and after photooxidation on C 7H 16 , SO 2 and C 7H 16 +SO 2, respectively and found adsorbates at the surface of TiO 2 affect their photocatalytic activities and conduction types of surface layer.
文摘By varying the hydrolysis and hydrothermal processing parameters in preparing TiO2 nanoparticles different sizes of TiO2 nanoparticles are obtained.(1) At higher autoclaving temperature,lower pH and longer autoclaving period,larger sizes of TiO2 nanoparticles are prepared.(2) The nanoporous electrodes made from sintering smaller TiO2 nanoparticles show relatively poor IPCE and low absorption in UV-Vis spectrum,(3) Higher IPCE can be achieved with TiO2 nanoporous electrodes made from sintering larger TiO2 nanoparticles.These electrodes are suitable for studying behavior of the photoelectrochemistry of dye sensitized nanoporous electrodes.
基金Project supported by National Natural Science Foundation of China （51077050）, Chinese Universities Scientific Fund.
文摘TiO2 semiconductive nanoparticles are added into mineral and ester based transformer oil to form semiconductive nanofluids (SNFs) with the aim of enhancing the oil’s insulating performance. Charge accumulation and decay characteristics of both pure oils and SNFs are measured by pulse electroacoustic (PEA) technique. The result reveals that compared with pure oil, SNFs have more uniform in- ternal electric fields with voltage applied and higher charge decay rate after removing the applied voltage. This is caused by the increase of shallow trap density in SNFs, due to the test results of thermally stimulated current (TSC). It is proposed that the electron trapping and de-trapping processes in shallow traps could be the main charge transport processes in the nanofluid transformer oil.
基金Projects(51176029,50876020) supported by the National Natural Science Foundation of ChinaProject(2011BAJ03B00) supported by the 12th Five-Year National Science and Technology Support Key Program of China Project(ybjj1124) supported by the Foundation of Graduate School of Southeast University,China
文摘In order to investigate the mechanism of nanoparticles enhancing the heat and mass transfer of the ammonia-water absorption process,several types of binary nanofluids were prepared by mixing Al2O3 nanoparticles with polyacrylic acid(PAA),TiO2 with polyethylene glycol(PEG 1000),and TiN,SiC,hydroxyapatite(noodle-like) with PEG 10000 to ammonia-water solution,respectively.The thermal conductivities were measured by using a KD2 Pro thermal properties analyzer.The influences of surfactant and ammonia on the dispersion stabilities of the binary nanofluids were investigated by the light absorbency ratio index methods.The results show that the type,content and size of nanoparticles,the temperature as well as the dispersion stability are the key parameters that affect the thermal conductivity of nanofluids.For the given nanoparticle material and the base fluid,the thermal conductivity ratio of the nanofluid to the ammonia-water liquid increases as the nanoparticle content and the temperature are increased,and the diameter of nanoparticle is decreased.Furthermore,the thermal conductivity ratio increases significantly by improving the stabilities of nanofluids,which is achieved by adding surfactants or performing the proper ammonia content in the fluid.
