Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine.Here,we have synthesized zinc oxide(ZnO)nanorods using zinc acetate and hexamethylenetetram...Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine.Here,we have synthesized zinc oxide(ZnO)nanorods using zinc acetate and hexamethylenetetramine as precursors followed by characterizing using X-ray diffraction,fourier transform infrared spectroscopy,scanning electron microscopy and transmission electron microscopy.The growth of synthesized zinc oxide nanorods was found to be very close to its hexagonal nature,which is confirmed by X-ray diffraction.The nanorod was grown perpendicular to the long-axis and grew along the[001]direction,which is the nature of ZnO growth.The morphology of synthesized ZnO nanorods from the individual crystalline nucleus was confirmed by scanning and transmission electron microscopy.The length of the nanorod was estimated to be around 21 nm in diameter and 50 nm in length.Our toxicology studies showed that synthesized ZnO nanorods exposure on hela cells has no significant induction of oxidative stress or cell death even in higher concentration(10μg/ml).The results suggest that ZnO nanorods might be a safer nanomaterial for biological applications.展开更多
In order to provide ultraviolet barrier, antifungal and antibacterial properties, nano-zinc oxide (ZnO) was added to lamellar zirconium phosphate (ZrP). The phosphate was synthesized via reaction of zirconium oxychlor...In order to provide ultraviolet barrier, antifungal and antibacterial properties, nano-zinc oxide (ZnO) was added to lamellar zirconium phosphate (ZrP). The phosphate was synthesized via reaction of zirconium oxychloride octahydrate and phosphoric acid following its chemical modification with Jeffamine and nano-ZnO. Diffractometric, morphological, thermal, structural and relaxometric evaluations were conducted. Fourier transform infrared spectroscopy (FTIR) revealed increase of the area between 4000 - 3000 cm<sup>-1</sup> due to the formation of ionic specie PO? <sup>+</sup>NH<sub>3</sub>-[C-(H)(CH<sub>3</sub>)-CH<sub>2</sub>-O-(C-(H)(CH<sub>3</sub>)-CH<sub>2</sub>-O)<sub>8</sub>-(CH<sub>2</sub>-CH<sub>2</sub>-O-CH<sub>3</sub>)] and nano-ZnO particles. Wide-angle X-ray diffraction indicated that intercalation of Jeffamine was successful. Thermogravimetry confirmed that nano-ZnO particle forced the expulsion of Jeffamine outside ZrP galleries. Scanning electron microscopy evidenced the Jeffamine intercalation and sample heterogeneity. Hydrogen molecular relaxation indicated the increase of molecular rigidity owing to the formation of ionic specie and the addition of nano-ZnO particles. It was postulated that a multifunctional and miscellaneous material constituted by as prepared ZrP, some delaminated ZrP platelets and nano-ZnO particles was achieved. The material has potential for usage as filler in polymeric composites.展开更多
Nano-sized zinc oxide(n ZnO) particles are one kind of the most commonly used metal oxide nanoparticles(NPs). This study compared the cytotoxic and embryotoxic effects of three increasing sized ZnO particles(φ30 nm, ...Nano-sized zinc oxide(n ZnO) particles are one kind of the most commonly used metal oxide nanoparticles(NPs). This study compared the cytotoxic and embryotoxic effects of three increasing sized ZnO particles(φ30 nm, 80-150 nm and 2 μm) in the flounder gill(FG) cells and zebrafish embryos, and analyzed the contribution of size, agglomeration and released Zn^(2+) to the toxic effects. All the tested ZnO particles were found to be highly toxic to both FG cells and zebrafish embryos. They induced growth inhibition, LDH release, morphological changes and apoptosis in FG cells in a concentration-, size-and time-dependent manner. Moreover, the release of LDH from the exposed FG cells into the medium occurred before the observable morphological changes happened. The ultrasonication treatment and addition of serum favored the dispersion of ZnO particles and alleviated the agglomeration, thus significantly increased the corresponding cytotoxicity. The released Zn^(2+) ions from ZnO particles into the extracellular medium only partially contributed to the cytotoxicity. All the three sizes of ZnO particles tested induced developmental malformations, decrease of hatching rates and lethality in zebrafish embryos, but size-and concentration-dependent toxic effects were not so obvious as in FG cells possibly due to the easy aggregation of ZnO particles in freshwater. In conclusion, both FG cells and zebrafish embryos are sensitive bioassay systems for safety assessment of ZnO particles and the environmental release of ZnO particles should be closely monitored as far as the safety of aquatic organisms is concerned.展开更多
Increasing need for materials with special features have brought various new inventions,one of the most promising hope for new material with special features and functionalities is composites materials.Thus,this study...Increasing need for materials with special features have brought various new inventions,one of the most promising hope for new material with special features and functionalities is composites materials.Thus,this study report an integration of zinc nanoparticles into kenaf/polyester polymer composite to introduce new behavior to the composite.The composite behaviors were compared for mechanical,thermal,moisture absorption and biodegradability properties.Prepared Zinc Oxide nanoparticles entrenched in the kenaf/polyestaer composites net structure through chemical bonds between kenaf/ZnO/polyester resin,existence of ZnO significantly influence the mechanical and thermals properties of composites.Thermal analysis based on(TGA)response revealed the integration of ZnO nanoparticles improved the thermal stability when thermal decomposition temperature beyond 3650 C.The thermal cracking decreased with present of ZnO and increase with kenaf content(layers).The modulus,Tensile strength,break at elongation,flexural modulus,flexural strength and impact strength of the composites with higher content kenaf/ZnO nanoparticle are 560 MPa,58MPa,1.8%,1300 PMa,68 MPa and 31 MPa,respectively.Thus,addition of kenaf layers and ZnO results in larger mechanical properties enhancement,the results of the contact angle show improvement in wetting of the fibres with addition of ZnO nanoparticles.展开更多
Traditional wastewater mostly contains pharmaceutical ingredients. Therefore, the wastewater must be completely free from antibiotics before its release into the environment. In the present study, photocatalytic degra...Traditional wastewater mostly contains pharmaceutical ingredients. Therefore, the wastewater must be completely free from antibiotics before its release into the environment. In the present study, photocatalytic degradation was done to investigate the removal efficiency of Oxytetracycline Dihydrate (OTC) using ZnO, ZnO/3%BaTiO<sub>3</sub> (3 BZ), ZnO/18%BaTiO<sub>3</sub> (18 BZ), ZnO/ 33%BaTiO3 (33 BZ) and ZnO/48%BaTiO<sub>3</sub> (48 BZ) under UV light. After the exposure time of 420 min, about 99.57% and 97.87% of OTC was degraded using ZnO and 3 BZ respectively. Further, increasing the amount of BaTiO<sub>3</sub> in ZnO prolongs the degradation time. Therefore, faster efficiency was found using ZnO nanoparticles. The observed reaction rate constant using ZnO was 0.00933 min<sup>-1</sup> which decreased to 0.00532 min<sup>-1</sup> using 48 BZ, indicating the decrease of reaction rate for increasing the amount of BaTiO<sub>3</sub>. Hence, the use of ZnO photocatalyst is anticipated to be a promising technique for the photocatalytic degradation of contaminated wastewater with oxytetracycline antibiotics using UV light.展开更多
Zinc oxide （ZnO） is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and ...Zinc oxide （ZnO） is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and dc magnetron co-sputtering technique. The effect of In-doping on structural, morphological and electrical properties is studied. The different dopant concentrations are accomplished by varying the direct current power of the In target while keeping the fixed radio frequency power of the ZnO target through the co-sputtering deposition technique by using argon as the sputtering gas at ambient temperature. The structural analysis confirms that all the grown thin films preferentially orientate along the c-axis with the wurtzite hexagonal crystal structure without having any kind of In oxide phases. The presenting Zn, 0 and In elements＇ chemical compositions are identified with EDX mapping analysis of the deposited thin films and the calculated M ratio has been found to decrease with the increasing In power. The surface topographies of the grown thin films are examined with the atomic force microscope technique. The obtained results reveal that the grown film roughness increases with the In power. The Hall measurements ascertain that all the grown films have n-type conductivity and also the other electrical parameters such as resistivity,mobility and carrier concentration are analyzed.展开更多
A new type of inorganic-polymer materials of epoxy Titanium Dioxide and Zinc Oxide was prepared. In this work, the mechanical properties of polymer composites reinforced with ceramic nanoparticles were investigated. T...A new type of inorganic-polymer materials of epoxy Titanium Dioxide and Zinc Oxide was prepared. In this work, the mechanical properties of polymer composites reinforced with ceramic nanoparticles were investigated. Three points bending tests demonstrated an enhancement in flexural strength and flexural modulus respectively, compared to the pure epoxy. The reinforcement of nanoparticulate materials was Titanium Dioxide and Zinc Oxide with various weight fraction. Experimental tests results indicated that the composite materials have significantly higher modulus of elasticity than the matrix material. It was found that the enhancement in modulus of elasticity was directly proportional to the weight fraction of reinforcement material, and that Zinc Oxide composites have higher modulus of elasticity than Titanium Dioxide composites with equivalent of weight fraction. The wear results showed that nanoparticles improved the wear resistance of epoxy nanocomposites, the Titanium Dioxide matrix particles could improve the wear resistance of the epoxy more efficiently than Zinc Oxide particles. The fatigue test showed that the fatigue resistance of epoxy Zinc Oxide matrix particles was higher than that of Titanium Dioxide matrix particles.展开更多
Zinc oxide (ZnO) and niobium oxide (NbOx) with a nano-island structure were deposited by a sputtering method on Al-coated glass substrates. Cells with a (ZnO or NbOx)/Al/glass|KNO3aq.|Al/ glass structure were assemble...Zinc oxide (ZnO) and niobium oxide (NbOx) with a nano-island structure were deposited by a sputtering method on Al-coated glass substrates. Cells with a (ZnO or NbOx)/Al/glass|KNO3aq.|Al/ glass structure were assembled, and electrochemical and photoelectrochemical properties were evaluated. The ZnO and NbOx electrodes had higher electrode potentials than the counter Al/glass electrode, and electron flows from the counter electrode to the ZnO and NbOx electrodes through the external circuit were commonly confirmed. In the ZnO-based cell, only faint photocurrent generation was seen, where Zn and Al elution from the ZnO electrode was found. In the NbOxbased cell, however, stable generation of electricity was successfully achieved, and electrode corrosion was not recognized even in microscopic observations. A photoelectrochemical conversion model was proposed based on potential-pH diagrams. In the case of nano-island structures formed at shorter NbOx deposition time, it was concluded that the photoelectrochemical reactions, which were proceeded in the immediate vicinity of the boundary among nano-islands, substrate, and electrolyte solution, were predominant for the photoelectrochemical conversion, and in the case of film structures with longer deposition time, the predominant reactions took place at the film surface.展开更多
Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further p...Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further performance enhancement. The research effort in the MEMS Piezoelectric vibration energy harvester designed using three types of cantilever materials, Lithium Niobate (LiNbO3), Aluminum Nitride (AlN) and Zinc Oxide (ZnO) with different substrate materials: aluminum, steel and silicon using COMSOL Multiphysics package were designed and analyzed. Voltage, mechanical power and electrical power versus frequency for different cantilever materials and substrates were modeled and simulated using Finite element method (FEM). The resonant frequencies of the LiNbO3/Al, AlN/Al and ZnO/Al systems were found to be 187.5 Hz, 279.5 Hz and 173.5 Hz, respectively. We found that ZnO/Al system yields optimum voltage and electrical power values of 8.2 V and 2.8 mW, respectively. For ZnO cantilever on aluminum, steel and silicon substrates, we found the resonant frequencies to be 173.5 Hz, 170 Hz and 175 Hz, respectively. Interestingly, ZnO/steel yields optimal voltage and electrical power values of 9.83 V and 4.02 mW, respectively. Furthermore, all systems were studied at different differentiate frequencies. We found that voltage and electrical power have increased as the acceleration has increased.展开更多
Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized...Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized via in-situ polymerization. The dispersion of nZnOp in copolymer matrixes and the effects of PEG and nZnOp particles on the crystallization behavior of the composites are studied by TEM, differential scanning calorimetry（DSC）, XRD and Fourier thansform infrared spectroscopy （FTIR ）. The results reveal that nZnOp particles are dispersed in the matrixes with nano-scale, and the addition of PEG induces more homogeneous dispersion of nZnOp. Simultaneously, these nanoparticles become nucleating centers during the crystallization of the matrixes. PEG segments can improve the flexibility of the PET molecular chain, resulting in the drop of the cold crystallization temperature and the rise of the crystallization rate of the composites. Furthermore, PEG （4 000） with the mass fraction of 10% can promote the crystallization rate of the composites. The mechanical properties show that the nano-particles strengthen and toughen the PET matrix, whereas PEG weakens these improve- ments.展开更多
In the early-stage diagnosis of lung cancer,the low-concentration(<5 ppm)volatile organic compounds(VOCs)are extensively identified to be the biomarkers for breath analysis.Herein,the urchin-like sodium(Na)-doped z...In the early-stage diagnosis of lung cancer,the low-concentration(<5 ppm)volatile organic compounds(VOCs)are extensively identified to be the biomarkers for breath analysis.Herein,the urchin-like sodium(Na)-doped zinc oxide(ZnO)nanoneedles were synthesized through a hydrothermal strategy with the addition of different contents of citric acid.The Na-doped ZnO gas sensor with a 3:1 molar ratio of Na^(+)and citric acid showed outstanding sensing properties with an optimal selectivity to various VOCs(formaldehyde(HCOH),isopropanol,acetone,and ammonia)based on working temperature regulation.Specifically,significantly enhanced sensitivity(21.3@5 ppm)compared with pristine ZnO(~7-fold),low limit of detection(LOD)(298 ppb),robust humidity resistance,and long-term stability of formaldehyde sensing performances were obtained,which can be attributed to the formation of a higher concentration of oxygen vacancies(20.98%)and the active electron transitions.Furthermore,the improved sensing mechanism was demonstrated by the exquisite band structure and introduction of the additional acceptor level,which resulted in the narrowed bandgap of ZnO.展开更多
Nowadays, fabrication of micro/nano-scale electronic devices with bottom-up approach is paid much research attention. Here, we provide a novel micro/nano-assembling method, which is accurate and efficient, especially ...Nowadays, fabrication of micro/nano-scale electronic devices with bottom-up approach is paid much research attention. Here, we provide a novel micro/nano-assembling method, which is accurate and efficient, especially suitable for the fabrication of micro/nano-scale electronic devices. Using this method, a self-powered ZnO/Sb-doped ZnO nanowire p–n homojunction ultraviolet detector(UVD) was fabricated, and the detailed photoelectric properties were tested. At a reverse bias of -0.1 V under UV light illumination, the photoresponse sensitivity of the UVD was 26.5 and the rise/decay time of the UVD was as short as 30 ms. The micro/nano-assembling method has wide potential applications in the fabrication of specific micro/nano-scale electronic devices.展开更多
基金supported by NASA funding NNX08BA47ANCC-1-02038+1 种基金NIH-1P20MD001822-1NSF(RISE)HRD-0734846
文摘Nanoparticles are increasingly being recognized for their potential utility in biological applications including nanomedicine.Here,we have synthesized zinc oxide(ZnO)nanorods using zinc acetate and hexamethylenetetramine as precursors followed by characterizing using X-ray diffraction,fourier transform infrared spectroscopy,scanning electron microscopy and transmission electron microscopy.The growth of synthesized zinc oxide nanorods was found to be very close to its hexagonal nature,which is confirmed by X-ray diffraction.The nanorod was grown perpendicular to the long-axis and grew along the[001]direction,which is the nature of ZnO growth.The morphology of synthesized ZnO nanorods from the individual crystalline nucleus was confirmed by scanning and transmission electron microscopy.The length of the nanorod was estimated to be around 21 nm in diameter and 50 nm in length.Our toxicology studies showed that synthesized ZnO nanorods exposure on hela cells has no significant induction of oxidative stress or cell death even in higher concentration(10μg/ml).The results suggest that ZnO nanorods might be a safer nanomaterial for biological applications.
文摘In order to provide ultraviolet barrier, antifungal and antibacterial properties, nano-zinc oxide (ZnO) was added to lamellar zirconium phosphate (ZrP). The phosphate was synthesized via reaction of zirconium oxychloride octahydrate and phosphoric acid following its chemical modification with Jeffamine and nano-ZnO. Diffractometric, morphological, thermal, structural and relaxometric evaluations were conducted. Fourier transform infrared spectroscopy (FTIR) revealed increase of the area between 4000 - 3000 cm<sup>-1</sup> due to the formation of ionic specie PO? <sup>+</sup>NH<sub>3</sub>-[C-(H)(CH<sub>3</sub>)-CH<sub>2</sub>-O-(C-(H)(CH<sub>3</sub>)-CH<sub>2</sub>-O)<sub>8</sub>-(CH<sub>2</sub>-CH<sub>2</sub>-O-CH<sub>3</sub>)] and nano-ZnO particles. Wide-angle X-ray diffraction indicated that intercalation of Jeffamine was successful. Thermogravimetry confirmed that nano-ZnO particle forced the expulsion of Jeffamine outside ZrP galleries. Scanning electron microscopy evidenced the Jeffamine intercalation and sample heterogeneity. Hydrogen molecular relaxation indicated the increase of molecular rigidity owing to the formation of ionic specie and the addition of nano-ZnO particles. It was postulated that a multifunctional and miscellaneous material constituted by as prepared ZrP, some delaminated ZrP platelets and nano-ZnO particles was achieved. The material has potential for usage as filler in polymeric composites.
基金supported by the National Natural Science Foundation of China(Grant Nos.41076075,31472274 and 31172391)Scholarship Foundation for Excellent Scientists of Shandong Province(Grant No.BS2011 SW054)open foundation from Institute of Marine Biodiversity and Evolution(Grant No.20132017)
文摘Nano-sized zinc oxide(n ZnO) particles are one kind of the most commonly used metal oxide nanoparticles(NPs). This study compared the cytotoxic and embryotoxic effects of three increasing sized ZnO particles(φ30 nm, 80-150 nm and 2 μm) in the flounder gill(FG) cells and zebrafish embryos, and analyzed the contribution of size, agglomeration and released Zn^(2+) to the toxic effects. All the tested ZnO particles were found to be highly toxic to both FG cells and zebrafish embryos. They induced growth inhibition, LDH release, morphological changes and apoptosis in FG cells in a concentration-, size-and time-dependent manner. Moreover, the release of LDH from the exposed FG cells into the medium occurred before the observable morphological changes happened. The ultrasonication treatment and addition of serum favored the dispersion of ZnO particles and alleviated the agglomeration, thus significantly increased the corresponding cytotoxicity. The released Zn^(2+) ions from ZnO particles into the extracellular medium only partially contributed to the cytotoxicity. All the three sizes of ZnO particles tested induced developmental malformations, decrease of hatching rates and lethality in zebrafish embryos, but size-and concentration-dependent toxic effects were not so obvious as in FG cells possibly due to the easy aggregation of ZnO particles in freshwater. In conclusion, both FG cells and zebrafish embryos are sensitive bioassay systems for safety assessment of ZnO particles and the environmental release of ZnO particles should be closely monitored as far as the safety of aquatic organisms is concerned.
文摘Increasing need for materials with special features have brought various new inventions,one of the most promising hope for new material with special features and functionalities is composites materials.Thus,this study report an integration of zinc nanoparticles into kenaf/polyester polymer composite to introduce new behavior to the composite.The composite behaviors were compared for mechanical,thermal,moisture absorption and biodegradability properties.Prepared Zinc Oxide nanoparticles entrenched in the kenaf/polyestaer composites net structure through chemical bonds between kenaf/ZnO/polyester resin,existence of ZnO significantly influence the mechanical and thermals properties of composites.Thermal analysis based on(TGA)response revealed the integration of ZnO nanoparticles improved the thermal stability when thermal decomposition temperature beyond 3650 C.The thermal cracking decreased with present of ZnO and increase with kenaf content(layers).The modulus,Tensile strength,break at elongation,flexural modulus,flexural strength and impact strength of the composites with higher content kenaf/ZnO nanoparticle are 560 MPa,58MPa,1.8%,1300 PMa,68 MPa and 31 MPa,respectively.Thus,addition of kenaf layers and ZnO results in larger mechanical properties enhancement,the results of the contact angle show improvement in wetting of the fibres with addition of ZnO nanoparticles.
文摘Traditional wastewater mostly contains pharmaceutical ingredients. Therefore, the wastewater must be completely free from antibiotics before its release into the environment. In the present study, photocatalytic degradation was done to investigate the removal efficiency of Oxytetracycline Dihydrate (OTC) using ZnO, ZnO/3%BaTiO<sub>3</sub> (3 BZ), ZnO/18%BaTiO<sub>3</sub> (18 BZ), ZnO/ 33%BaTiO3 (33 BZ) and ZnO/48%BaTiO<sub>3</sub> (48 BZ) under UV light. After the exposure time of 420 min, about 99.57% and 97.87% of OTC was degraded using ZnO and 3 BZ respectively. Further, increasing the amount of BaTiO<sub>3</sub> in ZnO prolongs the degradation time. Therefore, faster efficiency was found using ZnO nanoparticles. The observed reaction rate constant using ZnO was 0.00933 min<sup>-1</sup> which decreased to 0.00532 min<sup>-1</sup> using 48 BZ, indicating the decrease of reaction rate for increasing the amount of BaTiO<sub>3</sub>. Hence, the use of ZnO photocatalyst is anticipated to be a promising technique for the photocatalytic degradation of contaminated wastewater with oxytetracycline antibiotics using UV light.
基金Supported by the RU Top-Down under Grant No 1001/CSS/870019
文摘Zinc oxide （ZnO） is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and dc magnetron co-sputtering technique. The effect of In-doping on structural, morphological and electrical properties is studied. The different dopant concentrations are accomplished by varying the direct current power of the In target while keeping the fixed radio frequency power of the ZnO target through the co-sputtering deposition technique by using argon as the sputtering gas at ambient temperature. The structural analysis confirms that all the grown thin films preferentially orientate along the c-axis with the wurtzite hexagonal crystal structure without having any kind of In oxide phases. The presenting Zn, 0 and In elements＇ chemical compositions are identified with EDX mapping analysis of the deposited thin films and the calculated M ratio has been found to decrease with the increasing In power. The surface topographies of the grown thin films are examined with the atomic force microscope technique. The obtained results reveal that the grown film roughness increases with the In power. The Hall measurements ascertain that all the grown films have n-type conductivity and also the other electrical parameters such as resistivity,mobility and carrier concentration are analyzed.
文摘A new type of inorganic-polymer materials of epoxy Titanium Dioxide and Zinc Oxide was prepared. In this work, the mechanical properties of polymer composites reinforced with ceramic nanoparticles were investigated. Three points bending tests demonstrated an enhancement in flexural strength and flexural modulus respectively, compared to the pure epoxy. The reinforcement of nanoparticulate materials was Titanium Dioxide and Zinc Oxide with various weight fraction. Experimental tests results indicated that the composite materials have significantly higher modulus of elasticity than the matrix material. It was found that the enhancement in modulus of elasticity was directly proportional to the weight fraction of reinforcement material, and that Zinc Oxide composites have higher modulus of elasticity than Titanium Dioxide composites with equivalent of weight fraction. The wear results showed that nanoparticles improved the wear resistance of epoxy nanocomposites, the Titanium Dioxide matrix particles could improve the wear resistance of the epoxy more efficiently than Zinc Oxide particles. The fatigue test showed that the fatigue resistance of epoxy Zinc Oxide matrix particles was higher than that of Titanium Dioxide matrix particles.
文摘Zinc oxide (ZnO) and niobium oxide (NbOx) with a nano-island structure were deposited by a sputtering method on Al-coated glass substrates. Cells with a (ZnO or NbOx)/Al/glass|KNO3aq.|Al/ glass structure were assembled, and electrochemical and photoelectrochemical properties were evaluated. The ZnO and NbOx electrodes had higher electrode potentials than the counter Al/glass electrode, and electron flows from the counter electrode to the ZnO and NbOx electrodes through the external circuit were commonly confirmed. In the ZnO-based cell, only faint photocurrent generation was seen, where Zn and Al elution from the ZnO electrode was found. In the NbOxbased cell, however, stable generation of electricity was successfully achieved, and electrode corrosion was not recognized even in microscopic observations. A photoelectrochemical conversion model was proposed based on potential-pH diagrams. In the case of nano-island structures formed at shorter NbOx deposition time, it was concluded that the photoelectrochemical reactions, which were proceeded in the immediate vicinity of the boundary among nano-islands, substrate, and electrolyte solution, were predominant for the photoelectrochemical conversion, and in the case of film structures with longer deposition time, the predominant reactions took place at the film surface.
文摘Interest in energy harvesters has grown rapidly over the last decade. The cantilever shaped piezoelectric energy harvesting beam is one of the most employed designs, due to its simplicity and flexibility for further performance enhancement. The research effort in the MEMS Piezoelectric vibration energy harvester designed using three types of cantilever materials, Lithium Niobate (LiNbO3), Aluminum Nitride (AlN) and Zinc Oxide (ZnO) with different substrate materials: aluminum, steel and silicon using COMSOL Multiphysics package were designed and analyzed. Voltage, mechanical power and electrical power versus frequency for different cantilever materials and substrates were modeled and simulated using Finite element method (FEM). The resonant frequencies of the LiNbO3/Al, AlN/Al and ZnO/Al systems were found to be 187.5 Hz, 279.5 Hz and 173.5 Hz, respectively. We found that ZnO/Al system yields optimum voltage and electrical power values of 8.2 V and 2.8 mW, respectively. For ZnO cantilever on aluminum, steel and silicon substrates, we found the resonant frequencies to be 173.5 Hz, 170 Hz and 175 Hz, respectively. Interestingly, ZnO/steel yields optimal voltage and electrical power values of 9.83 V and 4.02 mW, respectively. Furthermore, all systems were studied at different differentiate frequencies. We found that voltage and electrical power have increased as the acceleration has increased.
基金Supported by the Program of Jiangsu Development & Reform Commission(2005)the Industrial-ization Boosting Program of College Scientific Reserach Achievements of the Education Department of Jiangsu Province(JHB06-03)~~
文摘Nano-ZnO particle （nZnOp） reinforced polyethylene glycol （PEG）/polyethylene terephthalate （PET） （nZnOp/PEG/PET） copolymeric composites with different mass fractions and molecular weights of PEG are synthesized via in-situ polymerization. The dispersion of nZnOp in copolymer matrixes and the effects of PEG and nZnOp particles on the crystallization behavior of the composites are studied by TEM, differential scanning calorimetry（DSC）, XRD and Fourier thansform infrared spectroscopy （FTIR ）. The results reveal that nZnOp particles are dispersed in the matrixes with nano-scale, and the addition of PEG induces more homogeneous dispersion of nZnOp. Simultaneously, these nanoparticles become nucleating centers during the crystallization of the matrixes. PEG segments can improve the flexibility of the PET molecular chain, resulting in the drop of the cold crystallization temperature and the rise of the crystallization rate of the composites. Furthermore, PEG （4 000） with the mass fraction of 10% can promote the crystallization rate of the composites. The mechanical properties show that the nano-particles strengthen and toughen the PET matrix, whereas PEG weakens these improve- ments.
基金the Outstanding Youth Foundation of Jiangsu Province of China(No.BK20211548)the Yangzhou Science and Technology Plan Project(No.YZ2023246)the Qinglan Project of Yangzhou University,and the Research Innovation Plan of Graduate Education Innovation Project in Jiangsu Province(No.KYCX23_3530).
文摘In the early-stage diagnosis of lung cancer,the low-concentration(<5 ppm)volatile organic compounds(VOCs)are extensively identified to be the biomarkers for breath analysis.Herein,the urchin-like sodium(Na)-doped zinc oxide(ZnO)nanoneedles were synthesized through a hydrothermal strategy with the addition of different contents of citric acid.The Na-doped ZnO gas sensor with a 3:1 molar ratio of Na^(+)and citric acid showed outstanding sensing properties with an optimal selectivity to various VOCs(formaldehyde(HCOH),isopropanol,acetone,and ammonia)based on working temperature regulation.Specifically,significantly enhanced sensitivity(21.3@5 ppm)compared with pristine ZnO(~7-fold),low limit of detection(LOD)(298 ppb),robust humidity resistance,and long-term stability of formaldehyde sensing performances were obtained,which can be attributed to the formation of a higher concentration of oxygen vacancies(20.98%)and the active electron transitions.Furthermore,the improved sensing mechanism was demonstrated by the exquisite band structure and introduction of the additional acceptor level,which resulted in the narrowed bandgap of ZnO.
基金supported by the National Natural Science Foundation of China (11374110, 51371085, 11304106)
文摘Nowadays, fabrication of micro/nano-scale electronic devices with bottom-up approach is paid much research attention. Here, we provide a novel micro/nano-assembling method, which is accurate and efficient, especially suitable for the fabrication of micro/nano-scale electronic devices. Using this method, a self-powered ZnO/Sb-doped ZnO nanowire p–n homojunction ultraviolet detector(UVD) was fabricated, and the detailed photoelectric properties were tested. At a reverse bias of -0.1 V under UV light illumination, the photoresponse sensitivity of the UVD was 26.5 and the rise/decay time of the UVD was as short as 30 ms. The micro/nano-assembling method has wide potential applications in the fabrication of specific micro/nano-scale electronic devices.
