Climate change and the consumption of non-renewable resources are considered as the greatest problems facing humankind.Because of this,photocatalysis research has been rapidly expanding.TiO2 nanoparticles have been ex...Climate change and the consumption of non-renewable resources are considered as the greatest problems facing humankind.Because of this,photocatalysis research has been rapidly expanding.TiO2 nanoparticles have been extensively investigated for photocatalytic applications including the decomposition of organic compounds and production of H2 as a fuel using solar energy. This article reviews the structure and electronic properties of TiO2,compares TiO2 with other common semiconductors used for photocatalytic applications and clarifies the advantages of using TiO2 nanoparticles.TiO2 is considered close to an ideal semi- conductor for photocatalysis but possesses certain limitations such as poor absorption of visible radiation and rapid recombination of photogenerated electron/hole pairs.In this review article,various methods used to enhance the photocatalytic characteristics of TiO2 including dye sensitization,doping,coupling and capping are discussed.Environmental and energy applications of TiO2, including photocatalytic treatment of wastewater,pesticide degradation and water splitting to produce hydrogen have been summarized.展开更多
The rapid development of information technology has led to an urgent need for devices with fast information storage and processing, a high density, and low energy consumption. Memristors are considered to be next-gene...The rapid development of information technology has led to an urgent need for devices with fast information storage and processing, a high density, and low energy consumption. Memristors are considered to be next-generation memory devices with all of the aforementioned advantages. Recently, organometallic halide perovskites were reported to be promising active materials for memristors, although they have poor stability and mediocre performance. Herein, we report for the first time the fabrication of stable and high-performance memristors based on inorganic halide perovskite （CsPbBr3, CPB）. The devices have electric field-induced bipolar resistive switching （ReS） and memory behaviors with a large on/off ratio （〉105）, low working voltage （〈1 V） and energy consumption, long data retention （〉104 s）, and high environmental stability, which are achieved via ZnO capping within the devices. Such a design can be adapted to various devices. Additionally, the heterojunction between the CPB and ZnO endows the devices with a light-induced ReS effect of more than 103 with a rapid response speed （〈1 ms）, which enables us to tune the resistance state by changing the light and electric field simultaneously. Such multifunctional devices achieved by the combination of information storage and processing abilities have potential applications for future computing that transcends traditional architectures.展开更多
Three active barrier materials （zeolite, ceramicite and light porous media） were applied for preventing nitrogen （N） release from eutrophic lake sediments. Long term experiment of two different lake sediments were...Three active barrier materials （zeolite, ceramicite and light porous media） were applied for preventing nitrogen （N） release from eutrophic lake sediments. Long term experiment of two different lake sediments were carded out and the effect of zeolite dose was evaluated. The results indicated that about 90%-100% of total N in overlying water was eliminated by using zeolite. While the N removal efficiency by ceramic was lower than that by zeolite, and light porous media present the lowest efficiency of 59%. Long term sediment incubation experiments indicated that two eutrophic sediments were both effective in preventing N release in spite of different release characteristics. Bio-zeolite capping technology was able to effectively inhibit the release of N from the sediment, and the zeolite dose was independently from N removal.展开更多
The 5′-cap structures of eukaryotic m RNAs are important for RNA stability, pre-m RNA splicing,m RNA export, and protein translation. Many viruses have evolved mechanisms for generating their own cap structures with ...The 5′-cap structures of eukaryotic m RNAs are important for RNA stability, pre-m RNA splicing,m RNA export, and protein translation. Many viruses have evolved mechanisms for generating their own cap structures with methylation at the N7 position of the capped guanine and the ribose 2′-Oposition of the first nucleotide, which help viral RNAs escape recognition by the host innate immune system. The RNA genomes of coronavirus were identified to have 5′-caps in the early1980 s. However, for decades the RNA capping mechanisms of coronaviruses remained unknown.Since 2003, the outbreak of severe acute respiratory syndrome coronavirus has drawn increased attention and stimulated numerous studies on the molecular virology of coronaviruses. Here, we review the current understanding of the mechanisms adopted by coronaviruses to produce the 5′-cap structure and methylation modification of viral genomic RNAs.展开更多
Bioreactive thin-layer capping（BTC）with biozeolite provides a potential remediation design that can sustainably treat N contamination from sediment and overlying water in eutrophic water bodies.Nitrogen（N）reductio...Bioreactive thin-layer capping（BTC）with biozeolite provides a potential remediation design that can sustainably treat N contamination from sediment and overlying water in eutrophic water bodies.Nitrogen（N）reduction using BTC with biozeolite was examined in a field incubation experiment in a eutrophic river in Yangzhou,Jiangsu Province,China.The biozeolite was zeolite with attached bacteria,including two isolated heterotrophic nitrifiers（Bacillus spp.）and two isolated aerobic denitrifiers（Acinetobacter spp.）.The results showed that the total nitrogen（TN）reduction efficiency of the overlying water by BTC with biozeolite（with thickness of about 2 mm）reached a maximum（56.69%）at day 34,and simultaneous heterotrophic nitrification and aerobic denitrification occurred in the BTC system until day 34.There was a significant difference in the TN concentrations of the overlying water between biozeolite capping and control（t-test;p〈0.05）.The biozeolite had very strong in situ bioregeneration ability.Carbon was the main source of nitrifier growth.However,both dissolved oxygen（DO）and carbon concentrations affected denitrifier growth.In particular,DO concentrations greater than 3 mg/L inhibited denitrifier growth.Therefore,BTC with biozeolite was found to be a feasible technique to reduce N in a eutrophic river.However,it is necessary to further strengthen the adaptability of aerobic denitrifiers through changing domestication methods or conditions.展开更多
Eu3＋ doped CaWO4 with tetragonal system were prepared at comparatively low temperature （125 ℃） in ethylene glycol medium. The phosphor was further investigated by X-ray difffactometer （XRD）, photoluminescence sp...Eu3＋ doped CaWO4 with tetragonal system were prepared at comparatively low temperature （125 ℃） in ethylene glycol medium. The phosphor was further investigated by X-ray difffactometer （XRD）, photoluminescence spectrophotometer （PL）, Fourier transform infra red （FT-IR） spectroscopy and transmission electron microscopy （TEM）. XRD analysis indicated a decrease in the unit cell volume of CaWO4 with increasing Eu3＋ ion concentration. It indicated the homogeneous substitution of Ca2＋ ions in CaWO4 by the Eu3＋ ions. TEM images showed that the particle size ranged from 20 to 200 nm and it could extend the application of the nanoparticles. The photoluminescence study showed that the intensity of electric dipole transition （SD0→TF2） at 614 nm dominated over the magnetic dipole transition （SD0→TFx） at 592 nm. The optimum concentration of Eu3＋ for the highest luminescence was found to be 20 at.%. The as prepared samples were found to be dispersible in water and methanol.展开更多
基金supported by the Department of Science and Technology, New Delhi (India)Department of Science & Technology,New Delhi for the Award of Junior Research Fellowship
文摘Climate change and the consumption of non-renewable resources are considered as the greatest problems facing humankind.Because of this,photocatalysis research has been rapidly expanding.TiO2 nanoparticles have been extensively investigated for photocatalytic applications including the decomposition of organic compounds and production of H2 as a fuel using solar energy. This article reviews the structure and electronic properties of TiO2,compares TiO2 with other common semiconductors used for photocatalytic applications and clarifies the advantages of using TiO2 nanoparticles.TiO2 is considered close to an ideal semi- conductor for photocatalysis but possesses certain limitations such as poor absorption of visible radiation and rapid recombination of photogenerated electron/hole pairs.In this review article,various methods used to enhance the photocatalytic characteristics of TiO2 including dye sensitization,doping,coupling and capping are discussed.Environmental and energy applications of TiO2, including photocatalytic treatment of wastewater,pesticide degradation and water splitting to produce hydrogen have been summarized.
文摘The rapid development of information technology has led to an urgent need for devices with fast information storage and processing, a high density, and low energy consumption. Memristors are considered to be next-generation memory devices with all of the aforementioned advantages. Recently, organometallic halide perovskites were reported to be promising active materials for memristors, although they have poor stability and mediocre performance. Herein, we report for the first time the fabrication of stable and high-performance memristors based on inorganic halide perovskite （CsPbBr3, CPB）. The devices have electric field-induced bipolar resistive switching （ReS） and memory behaviors with a large on/off ratio （〉105）, low working voltage （〈1 V） and energy consumption, long data retention （〉104 s）, and high environmental stability, which are achieved via ZnO capping within the devices. Such a design can be adapted to various devices. Additionally, the heterojunction between the CPB and ZnO endows the devices with a light-induced ReS effect of more than 103 with a rapid response speed （〈1 ms）, which enables us to tune the resistance state by changing the light and electric field simultaneously. Such multifunctional devices achieved by the combination of information storage and processing abilities have potential applications for future computing that transcends traditional architectures.
基金supported by the program of International Science & Technology Cooperation from Chinese Ministry of Science and Technology (No. 2010DFA94550,2010KW-24-1)the National Natural Science Foundation of China (No. 50830303)+1 种基金the Major Science and Technology Program for Water Pollution Control and Treatment (No. 2009ZX07317-007-001)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0853)
文摘Three active barrier materials （zeolite, ceramicite and light porous media） were applied for preventing nitrogen （N） release from eutrophic lake sediments. Long term experiment of two different lake sediments were carded out and the effect of zeolite dose was evaluated. The results indicated that about 90%-100% of total N in overlying water was eliminated by using zeolite. While the N removal efficiency by ceramic was lower than that by zeolite, and light porous media present the lowest efficiency of 59%. Long term sediment incubation experiments indicated that two eutrophic sediments were both effective in preventing N release in spite of different release characteristics. Bio-zeolite capping technology was able to effectively inhibit the release of N from the sediment, and the zeolite dose was independently from N removal.
基金supported by the China "973" Basic Research Program (2013CB911101)China NSFC grants (81130083 and 81271817)
文摘The 5′-cap structures of eukaryotic m RNAs are important for RNA stability, pre-m RNA splicing,m RNA export, and protein translation. Many viruses have evolved mechanisms for generating their own cap structures with methylation at the N7 position of the capped guanine and the ribose 2′-Oposition of the first nucleotide, which help viral RNAs escape recognition by the host innate immune system. The RNA genomes of coronavirus were identified to have 5′-caps in the early1980 s. However, for decades the RNA capping mechanisms of coronaviruses remained unknown.Since 2003, the outbreak of severe acute respiratory syndrome coronavirus has drawn increased attention and stimulated numerous studies on the molecular virology of coronaviruses. Here, we review the current understanding of the mechanisms adopted by coronaviruses to produce the 5′-cap structure and methylation modification of viral genomic RNAs.
基金supported by the National Science and Technology Pillar Program(No.2012BAC04B02)the National Natural Science Fund of China(No.51408243)+3 种基金the Natural Science Foundation of Fujian Province of China(No.2015J01213)the Fundamental Research Funds for Central Universities(No.11QZR07)the Science and Technology Plan Fund of Quanzhou City(No.2014Z218)the Research Funds of Huaqiao University(No.14BS216)
文摘Bioreactive thin-layer capping（BTC）with biozeolite provides a potential remediation design that can sustainably treat N contamination from sediment and overlying water in eutrophic water bodies.Nitrogen（N）reduction using BTC with biozeolite was examined in a field incubation experiment in a eutrophic river in Yangzhou,Jiangsu Province,China.The biozeolite was zeolite with attached bacteria,including two isolated heterotrophic nitrifiers（Bacillus spp.）and two isolated aerobic denitrifiers（Acinetobacter spp.）.The results showed that the total nitrogen（TN）reduction efficiency of the overlying water by BTC with biozeolite（with thickness of about 2 mm）reached a maximum（56.69%）at day 34,and simultaneous heterotrophic nitrification and aerobic denitrification occurred in the BTC system until day 34.There was a significant difference in the TN concentrations of the overlying water between biozeolite capping and control（t-test;p〈0.05）.The biozeolite had very strong in situ bioregeneration ability.Carbon was the main source of nitrifier growth.However,both dissolved oxygen（DO）and carbon concentrations affected denitrifier growth.In particular,DO concentrations greater than 3 mg/L inhibited denitrifier growth.Therefore,BTC with biozeolite was found to be a feasible technique to reduce N in a eutrophic river.However,it is necessary to further strengthen the adaptability of aerobic denitrifiers through changing domestication methods or conditions.
基金Project supported by the Department of Science and Technology (DST), New Delhi, Govt. of India
文摘Eu3＋ doped CaWO4 with tetragonal system were prepared at comparatively low temperature （125 ℃） in ethylene glycol medium. The phosphor was further investigated by X-ray difffactometer （XRD）, photoluminescence spectrophotometer （PL）, Fourier transform infra red （FT-IR） spectroscopy and transmission electron microscopy （TEM）. XRD analysis indicated a decrease in the unit cell volume of CaWO4 with increasing Eu3＋ ion concentration. It indicated the homogeneous substitution of Ca2＋ ions in CaWO4 by the Eu3＋ ions. TEM images showed that the particle size ranged from 20 to 200 nm and it could extend the application of the nanoparticles. The photoluminescence study showed that the intensity of electric dipole transition （SD0→TF2） at 614 nm dominated over the magnetic dipole transition （SD0→TFx） at 592 nm. The optimum concentration of Eu3＋ for the highest luminescence was found to be 20 at.%. The as prepared samples were found to be dispersible in water and methanol.
