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作者： ogugua paul chinonso 哈尔滨工业大学

学位级别：硕士

检测食品污染物的常规方法非常有限。例如,色谱法是用于分离气体或液体混合物的技术。尽管基于色谱法的技术已被食品和药物管理局(FDA)、其他联邦机构、工业部门以及学术界广泛用作标准方法,但通常使用色谱法的检测三聚氰胺的浓度极限(L... 详细信息

检测食品污染物的常规方法非常有限。例如,色谱法是用于分离气体或液体混合物的技术。尽管基于色谱法的技术已被食品和药物管理局(FDA)、其他联邦机构、工业部门以及学术界广泛用作标准方法,但通常使用色谱法的检测三聚氰胺的浓度极限(LOD)仅可以达到十亿分之几(ppb)的水平。因此,需要更好的技术来实现食品检测。高通量、可重复性、选择性、简单性和高灵敏度的特点使得表面增强拉曼光谱(SERS)技术能够应用到生物科学领域。贵金属的纳米颗粒,特别是金(Au),在可见光和近红外(NIR)光谱范围内表现出表面等离子共振(SPP),其等离子体模式的形成源自于电磁场驱动的自由电子的集体振荡。这项工作旨在使用有限差分时域(FDTD)方法设计具有高SERS增强因子和低成本的NPs-衬底结构。结果表明,对于所研究的SiO、Ge和AlO三种基板,Ag颗粒所激发的SERS效应与先前实验的结果相一致:SiO>Ge>AlO。进一步的模拟表明,Ag颗粒在Al基底上所表现出的拉曼散射强度大于在SiO、Ge和AlO基底上的强度。这表明相对于半导体基底而言,铝基底边缘位置及其周围的电磁场得到了更多的强化。更重要的是,模拟结果表明AuNPs-Al基底结构也具有拉曼散射强化作用(AuNPs在Al基底上的局部电场增强效应能够获得更强的拉曼信号)。最优结果来自于AuNP和AgNP的协同效应。当两种或更多种材料与金属结构组合时,由于电磁和化学增强的协同作用,微结构能够获得更好的拉曼强化效果。在特定范围内改变球体直径和颗粒间距,获得了关于SERS的更多研究结果。为了兼顾实际应用中的成本与效率问题,需适当减少材料的使用,以确保在小型化的基础上带来更多的强化效果。此外,通过调控颗粒尺寸、颗粒间距和基板类型,得到了共振波长的激发机理。最后,考虑了单晶Au纳米结构的消光光谱。结果表明,相同粒径的消光峰具有红移现象。其原因是纳米结构之间所发生的等离子体耦合效应。该结果对于优良SERS底物的开发和应用具有一定的指导意义,并为解决食源性细菌的世界性难题提供了新的解决方法。

关键词：时域有限差分法表面增强拉曼散射基底小型化结构指纹

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Analysis of heat flow diagram of small-scale power generation system:Innovative approaches for improving techno-economic and ecological indices

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Science China(Technological Sciences) 2020年第11期63卷 2256-2274页

作者： SHAGDAR Enkhbayar SHUAI Yong GUENE LOUGOU Bachirou GANBOLD Enkhjin chinonso ogugua paul TAN HePing Key Laboratory of Aerospace Thermophysics of Ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin 150001China School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Energy Science and Power Engineering Mongolian University of Science and TechnologyUlaanbaatar 14191Mongolia School of Mechanical and Power Engineering Harbin University of Science and TechnologyHarbin 150001China

In this paper,the heat flow diagram of steam turbine model K-6-35 has been analyzed for innovative approaches towards improving the techno-economic and ecological indices of the small-scale power generation *** numerical analysis is performed using IPSEpro process simulation software based on heat balance method under four different *** was found that the study of Solar Assisted Power Generation(SAPG)system has important practical significance in power generation with minimum pollutants and maximum *** fuel-saving(FS)and power-boosting(PB)operation modes of the SAPG system are *** types of stand-alone solar thermal power plants exhibited very low overall efficiency with many ecological advantages compared to the conventional thermal power plant based on fossil ***,SAPG system with FS mode presented higher techno-economic indices and operation *** important reduction in fuel consumption and pollutant emissions could be obtained with SAPG *** the hourly,daily,monthly,and yearly amount of saved fuel and reduced pollutants in the whole power plant,the SAPG system with FS mode can largely contribute to high ecological indices power generation.A thermal efficiency increased by 1.31%with specific equivalent fuel consumption decreased by 22.54 g/kWh was obtained with SAPG *** coal consumption was reduced by 4.75%when SAPG system operates in FS mode.

关键词： heat flow diagram solar assisted power generation parabolic trough collector solar thermal power plant techno-economic indices genetic algorithm

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A Mathematical Model of an Evaporative Cooling Pad Using Sintered Nigerian Clay

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Journal of Minerals and Materials Characterization and Engineering 2012年第11期11卷 1113-1120页

作者： Chukwuneke Jeremiah Lekwuwa Ajike Chinagorom Ogbu Achebe chinonso Hubert Okolie paul Chukwulozie Department of Mechanical Engineering Nnamdi Azikiwe University PMB 5025 Awka Nigeria

Overtime, reduction in the amount of heat generated in engineering systems in operations have been of great concern and have continuously been under study. It is in line with the above that this research work developed a mathematical model of an evaporative cooling pad using sintered Nigerian clay. A physical model of the evaporative cooling phenomenon was developed followed by the derivation of the governing equations describing the energy and mass transfer for the clay model from the laws of conservation of continuum mechanics. A set of reasonable and appropriate as-sumptions were imposed upon the physical model. Constitutive relationships were also developed for further analysis of the developed equations. The finite element model of numerical methods was used to analyse the energy transfer governing equations which resulted in the determination of the temperature of the exposed boundary surface at any given time, t2 after the commencement of the evaporative cooling processes. In this paper, it was found out that surface temperature differences could be as much as 6?C in the first cycle of evaporative cooling with the potential of further reduction. Further, an equation for the prediction of the effectiveness of an evaporative cooling system using clay modeled cooling pads was developed. The findings in this research work can be applied in the design, construction and maintenance of evaporative coolers used to dissipate waste heat when a large amount of natural water is not readily available or if for environmental and safety reasons the large water body can no longer absorb waste heat.

关键词： Evaporative Cooling Nigerian Clay Finite Difference Model Energy Transfer Cooling Pad Moulded Clay Material Heat Transfer Refrigeration Temperature

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Evaluation of Quantitative Phytochemicals, Liver Enzymes and Histological Changes in Isoniazid Induced Hepatotoxicity in Adult Male Wistar Rats Treated with Aqueous Extracts of <i>Brysocarpus coccineus</i>

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Advances in Enzyme Research 2017年第3期5卷 33-44页

作者： Kashini Andrew Nachamada Solomon Emmanuel Deborah Chioma Ejiogu chinonso Nicodemus Chima Fatima Mohammed Yahuza Emmanuel Chukwuemeka Umeh Philemon paul Mshelia Department of Human Physiology Faculty of Basic Medical SciencesCollege of Medical SciencesAhmadu Bello University ZariaNigeria Department of Human Physiology College of Medical SciencesAbubakar Tafawa Balewa UniversityBauchiNigeria

Isoniazid induced hepatotoxicity is a major concern in patients taking anti tuberculosis treatment and prophylaxis. It can result in elevated serum liver enzymes and hepatic failure. The aim of the study was to evaluate the phytochemicals and ameliorative effects of aqueous extracts of Brysocarpus coccineus on serum liver enzymes in isoniazid (INH) induced hepatotoxicity in adult male Wistar rats. Thirty six (36) adult male Wistar rats were divided into six groups of six rats each and were treated orally for 30 days as follows: Group I: 1 ml/kg of distilled water;group II: Isoniazid (27 mg/kg);group III: Isoniazid (27 mg/kg) + Livolin forte (20 mg/kg);group IV: Isoniazid (27 mg/kg) + B. coccineus (200 mg/kg);group V: Isoniazid (27 mg/kg) + B. coccineus (400 mg/kg);group VI: Isoniazid (27 mg/kg) + B. coccineus (800 mg/kg). At the end of the experiments, the Wistar rats were sacrificed and sera obtained for liver enzymes assay, whereas the liver tissue was also harvested and used for histological studies. Tanins, saponins, alkaloids and flavonoids were quantitatively present at 2.29%, 18.05%, 23.24% and 18.99%, respectively. There was an increase in the serum AST and ALT in the isoniazid treated group, which was reversed by livolin forte and the aqueous extracts at a dose of 200 mg/kg, however the extracts increased the serum levels of AST and ALT at higher doses, which was however not significant (p > 0.05) when compared to the controls. There was evidence of a reduction in hepatocytes damage in the extract treated groups when compared to the Isoniazid untreated group. In conclusion, aqueous extracts of B. coccineus shows hepatoprotective effects at 200 mg/kg in isoniazid hepatotoxicity in adult male Wistar rats.

关键词： Brysocarpus coccineus Isoniazid Hepatotoxicity Phytochemicals

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