The Experts below are selected from a list of 367449 Experts worldwide ranked by ideXlab platform
Sami Ramadan - One of the best experts on this subject based on the ideXlab platform.
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love mode surface acoustic wave devices based on multilayers of teo2 ZnO 112 0 si 1 0 0 with high sensitivity and temperature stability
Ultrasonics, 2017Co-Authors: Jingting Luo, Aojie Quan, Guangxing Liang, Zhuanghao Zheng, Sami RamadanAbstract:A multilayer structure of TeO2/interdigital transducers (IDTs)/ZnO(112¯0)/Si(100) was proposed and investigated to achieve both high sensitivity and temperature-stability for bio-sensing applications. Dispersions of phase velocities, electromechanical coupling coefficients K2, temperature coefficient of delay (TCD) and sensitivity in the multilayer structures were simulated as functions of normalized thicknesses of ZnO (hZnO/λ) and TeO2 (hTeO2/λ) films. The fundamental mode of Love mode (LM) - surface acoustic wave (SAW) shows a larger value of K2 and higher sensitivity compared with those of the first mode. TeO2 film with a positive TCD not only compensates the temperature effect induced due to the negative TCD of ZnO(112¯0)/Si(100), but also enhances the sensitivity of the love mode device. The optimal normalized thickness ratios were identified to be hTeO2/λ=0.021 and hZnO/λ=0.304, and the devices with such structures can which generate a normalized sensitivity of -1.04×10-3m3/kg, a TCD of 0.009ppm/°C, and a K2 value of 2.76%.
Yongsheng Chen - One of the best experts on this subject based on the ideXlab platform.
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the impact of ZnO nanoparticle aggregates on the embryonic development of zebrafish danio rerio
Nanotechnology, 2009Co-Authors: Xiaoshan Zhu, Jiangxin Wang, Xuezhi Zhang, Yung Chang, Yongsheng ChenAbstract:With extensive use of metal oxide nanoparticles (NPs) in a variety of applications comes a higher potential of release into aquatic environments. NPs tend to form much larger aggregates in water, which are expected to settle down to the bottom of the water column and possibly get mixed with the sediments. However, little is known about the environmental impacts and biological effects of these aggregated NPs in the sediment column. In this study, we examined the sedimentation of nanoscale ZnO particles (nZnO) in zebrafish culture medium, and assessed the toxicity of settled nZnO aggregates on developing zebrafish embryos and larvae. Given the known dissolution of nZnO particles to release Zn2+, we also assessed the toxic effect of soluble Zn2+ in this organism. We demonstrated that within 48?h, micron-sized nZnO aggregates were formed and settled out of the culture medium. These aggregates were found to exert dose-dependent toxicity to zebrafish embryos and larvae, reducing the hatching rate and causing pericardial edema. The observed toxicity of the nZnO aggregates was not likely a result solely of particle dissolution, as soluble Zn2+ alone caused much less toxicity to zebrafish embryos than nZnO. Instead, the combination of both nZnO and Zn2+ may contribute to the embryonic toxicity, possibly by increasing reactive oxidative species (ROS) and/or compromising the cellular oxidative stress response. Interestingly, we demonstrated that one type of formulated sediments could mitigate the toxicity of nZnO aggregates, highlighting a possible countermeasure to reduce the adverse impact of nZnO aggregates on the environment.
M. S. Ramachandra Rao - One of the best experts on this subject based on the ideXlab platform.
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Zn-vacancy induced violet emission in p-type phosphorus and nitrogen codoped ZnO thin films grown by pulsed laser deposition
Applied Surface Science, 2015Co-Authors: Ramanjaneyulu Mannam, Senthil Kumar Eswaran, Nandita Dasgupta, M. S. Ramachandra RaoAbstract:Abstract We report on the growth of violet emitting p-type ZnO thin films, with phosphorous (P) and nitrogen (N) codoping, using pulsed laser deposition. XPS studies show that the phosphorous is substituted at Zn site, whereas nitrogen is substituted at oxygen site. Hall measurements confirmed the p-type nature in codoped ZnO thin films. I-V characteristics of the heterojunction formed by n-Si and P, N: ZnO showed rectifying nature. Strong violet emission in PL spectra is attributed to the formation of zinc vacancies. We propose a defect complex, (PZn-VZn-4NO), which acts as an effective acceptor in the P and N codoped ZnO.
Jingting Luo - One of the best experts on this subject based on the ideXlab platform.
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love mode surface acoustic wave devices based on multilayers of teo2 ZnO 112 0 si 1 0 0 with high sensitivity and temperature stability
Ultrasonics, 2017Co-Authors: Jingting Luo, Aojie Quan, Guangxing Liang, Zhuanghao Zheng, Sami RamadanAbstract:A multilayer structure of TeO2/interdigital transducers (IDTs)/ZnO(112¯0)/Si(100) was proposed and investigated to achieve both high sensitivity and temperature-stability for bio-sensing applications. Dispersions of phase velocities, electromechanical coupling coefficients K2, temperature coefficient of delay (TCD) and sensitivity in the multilayer structures were simulated as functions of normalized thicknesses of ZnO (hZnO/λ) and TeO2 (hTeO2/λ) films. The fundamental mode of Love mode (LM) - surface acoustic wave (SAW) shows a larger value of K2 and higher sensitivity compared with those of the first mode. TeO2 film with a positive TCD not only compensates the temperature effect induced due to the negative TCD of ZnO(112¯0)/Si(100), but also enhances the sensitivity of the love mode device. The optimal normalized thickness ratios were identified to be hTeO2/λ=0.021 and hZnO/λ=0.304, and the devices with such structures can which generate a normalized sensitivity of -1.04×10-3m3/kg, a TCD of 0.009ppm/°C, and a K2 value of 2.76%.
Xiaoshan Zhu - One of the best experts on this subject based on the ideXlab platform.
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the impact of ZnO nanoparticle aggregates on the embryonic development of zebrafish danio rerio
Nanotechnology, 2009Co-Authors: Xiaoshan Zhu, Jiangxin Wang, Xuezhi Zhang, Yung Chang, Yongsheng ChenAbstract:With extensive use of metal oxide nanoparticles (NPs) in a variety of applications comes a higher potential of release into aquatic environments. NPs tend to form much larger aggregates in water, which are expected to settle down to the bottom of the water column and possibly get mixed with the sediments. However, little is known about the environmental impacts and biological effects of these aggregated NPs in the sediment column. In this study, we examined the sedimentation of nanoscale ZnO particles (nZnO) in zebrafish culture medium, and assessed the toxicity of settled nZnO aggregates on developing zebrafish embryos and larvae. Given the known dissolution of nZnO particles to release Zn2+, we also assessed the toxic effect of soluble Zn2+ in this organism. We demonstrated that within 48?h, micron-sized nZnO aggregates were formed and settled out of the culture medium. These aggregates were found to exert dose-dependent toxicity to zebrafish embryos and larvae, reducing the hatching rate and causing pericardial edema. The observed toxicity of the nZnO aggregates was not likely a result solely of particle dissolution, as soluble Zn2+ alone caused much less toxicity to zebrafish embryos than nZnO. Instead, the combination of both nZnO and Zn2+ may contribute to the embryonic toxicity, possibly by increasing reactive oxidative species (ROS) and/or compromising the cellular oxidative stress response. Interestingly, we demonstrated that one type of formulated sediments could mitigate the toxicity of nZnO aggregates, highlighting a possible countermeasure to reduce the adverse impact of nZnO aggregates on the environment.
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comparative toxicity of several metal oxide nanoparticle aqueous suspensions to zebrafish danio rerio early developmental stage
Journal of Environmental Science and Health Part A-toxic\ hazardous Substances & Environmental Engineering, 2008Co-Authors: Xiaoshan Zhu, Lin Zhu, Zhenghua Duan, Yupeng LangAbstract:With the emergence of manufactured nanomaterials, it is urgent to carry out researches on their potential environmental impacts and biological effects. To better understand the potential ecotoxicological impacts of metal oxide nanoparticles released to aquatic environments, the zebrafish 96-h embryo-larval bioassay was used to assess and compare the developmental toxicities of nanoscale zinc oxide (nZnO), titanium dioxide (nTiO2) and alumina (nAl2O3) aqueous suspensions. Toxicological endpoints such as zebrafish embryos or larvae survival, hatching rate and malformation were noted and described within 96 h of exposure. Meanwhile, a comparative experiment with their bulk counterparts (i.e., ZnO/bulk, TiO2/bulk and Al2O3/bulk) was conducted to understand the effect of particle size on their toxicities. The results showed that: (i) both nZnO and ZnO/bulk aqueous suspensions delayed zebrafish embryo and larva development, decreased their survival and hatching rates, and caused tissue damage. The 96-h LC50 of ...
