Formation of Magnetic Graphene Nanosheets for Rapid Enrichment and Separation of Methyl Orange from Water

Zhang, Feng-Jun,Zhang, Zhuo,Xie, Fa-Zhi,Xuan, Han,Xia, Hong-Chen,Zhu, Lei,Oh, Won-Chun The Korean Ceramic Society 2014 한국세라믹학회지 Vol.51 No.6

Magnetic-graphene nanosheets have been synthesized via a simple effective chemical precipitation method followed by heat treatment. The composite nanosheets are super paramagnetic at room temperature and can be separated by an external magnetic field. The prepared magnetic-graphene nanosheets were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and BET surface area analysis. The results demonstrated the successful attachment of iron oxide nanoparticles to graphene nanosheets. It was found that the attached nanoparticles were mainly $Fe_3O_4$. The magnetic-graphene nanosheets showed near complete methyl orange removal within 10 mintues and would be practically usable for methyl orange separation from water.

Visible Light Photoelectrocatalytic Properties of Novel Yttrium Treated Carbon Nanotube/Titania Composite Electrodes

Zhang, Feng-Jun,Chen, Ming-Liang,Zhang, Kan,Oh, Won-Chun Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.1

Photoelectrocatalytic decolorization of methlene blue (MB) in the presence of two types of carbon nanotube/titania and yttrium-treated carbon nanotube/titania electrodes in aqueous solutions were studied under visible light. The prepared composite electrodes were characterized by X-ray diffraction, transmission and scanning electron microscopy, energy dispersive X-ray analysis, and photoelectrocatalytic activity. The photoelectrocatalytic performances of the supported catalysts were evaluated for the decolorization of MB solution under visible light irradiation. The results showed that yttrium incorporation enhanced the decolorization rate of MB. It was found that the photoelectrocatalytic degradation of a MB solution could be attributed to the combined effects caused by the photo-degradation of titania, the electron assistance of carbon nanotube network, the enhancement of yttrium and a function of the applied potential. The repeatability of photocatalytic activity was also tested. The presence of yttrium enhanced the hydrophillicity of yttrium-carbon nanotubes/titania electrode because more OH groups can be adsorbed on the surface.

Operational modal analysis of Canton Tower by a fast frequency domain Bayesian method

Feng-Liang Zhang,Yan-Chun Ni,Yan-Chun Ni,You-Wu Wang 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.17 No.2

The Canton Tower is a high-rise slender structure with a height of 610 m. A structural health monitoring system has been instrumented on the structure, by which data is continuously monitored. This paper presents an investigation on the identified modal properties of the Canton Tower using ambient vibration data collected during a whole day (24 hours). A recently developed Fast Bayesian FFT method is utilized for operational modal analysis on the basis of the measured acceleration data. The approach views modal identification as an inference problem where probability is used as a measure for the relative plausibility of outcomes given a model of the structure and measured data. Focusing on the first several modes, the modal properties of this supertall slender structure are identified on non-overlapping time windows during the whole day under normal wind speed. With the identified modal parameters and the associated posterior uncertainty, the distribution of the modal parameters in the future is predicted and assessed. By defining the modal root-mean-square value in terms of the power spectral density of modal force identified, the identified natural frequencies and damping ratios versus the vibration amplitude are investigated with the associated posterior uncertainty considered. Meanwhile, the correlations between modal parameters and temperature, modal parameters and wind speed are studied. For comparison purpose, the frequency domain decomposition (FDD) method is also utilized to identify the modal parameters. The identified results obtained by the Bayesian method, the FDD method and a finite element model are compared and discussed.

수산물 시장에서 제품과 서비스 품질이 고객만족에 미치는 영향에 관한 연구

장춘봉 ( Chun Feng Zhang ),장영수 ( Young Soo Jang ) 한국수산경영학회 2010 수산경영론집 Vol.41 No.3

In this paper we aim to find out consumer behavior based on fish shares in their buying ingredients, path segmentation, product and service quality, customer satisfaction and then we try to analyze the impact of them on each consumer buying behavior. In this study, first, consumers, divided by general merchandise retail store and traditional fish retail store, these also divided by two groups that are with high spending group and low spending group, so totally we have four parts of consumer behavior segmentation market profiles. Second, we analysis the affect of each factor on consumer behavior. That is, we try to analysis the effect of product and service quality on customer satisfaction in four seafood market group.

수산물 소비에 대한 가치체계 분석과 시장세분화에 관한 연구

장춘봉 ( Chun Feng Zhang ),장영수 ( Young Soo Jang ) 한국수산경영학회 2011 수산경영론집 Vol.42 No.2

Values are lasting beliefs that are at the center of human behavior and not be often changed. Different values make different behaviors, and similar values form similar behaviors. Consumers` values affect not only the cognitive process but also behaviors in a powerful and comprehensive way. There have been many studies regarding prediction of consumer patterns and identification, measurement methods of values. This is because if we can accurately measure the value system, it can be used in many areas of marketing such as market segmentation, new product development, and advertisement. In case of seafood, it is also necessary to make marketing strategies by segmenting consumers based on their value systems. The objectives of this study are as follows: First, it is to find out the connection process from the properties of seafood products that consumers consider important, to the benefits, and finally to the values they pursue by applying the means-end chain theory, using the Laddering method. Second, using a two-step cluster analysis, we aim to segment seafood markets based on consumers` values and investigate characteristics of segmented markets. Based on objectives, it is expected that this study would provide informations on seafood consumers and help to establish seafood marketing strategies for producers and distributors. Analytical results of the value system using a means-end chain theory indicated that there were seven complete links, that is, ladders among fresh seafood products. In case of processed seafood products, there were total 9 complete ladders. The empirical analytical results of market segmentation according to the values showed fresh seafood products were divided into three groups. In case of processed seafood products were segmented into two groups.

Electrochemical Preparation of TiO₂/CNT Electrodes with a TNB Electrolyte and Their Photoelectrocatalytic Effects

Zhang, Feng-Jun,Chen, Ming-Liang,Oh, Won-Chun The Korean Ceramic Society 2009 한국세라믹학회지 Vol.46 No.4

We investigate a method for the electrochemical preparation of titanium dioxide/carbon nanotube ($TiO_2$/CNT) composites involving the electroplating of Ti in a titanium n-butoxide (TNB) electrolyte into a CNT matrix. The BET surface areas of $TiO_2$/CNT composites decreased as electrochemical operating time increased. Changes in XRD patterns showed a typical anatase type on the $TiO_2$/CNT composite prepared with a CNT matrix by the electroplating method in the TNB solution. In SEM micrographs, the titanium complex particles were uniformly distributed on the CNT surface. The results of chemical elemental analysis for the $TiO_2$/CNT composites showed that most of the spectra for these samples produced stronger peaks for carbon and Ti metal than those of any other element. Finally, the prominent photoelectrocatalytic (PEC) activities of the $TiO_2$/CNT composites could be attributed to the combined effects of photodegradation of $TiO_2$, electron assistance of CNT and the application of a sufficient voltage.

Synthesis and Characterization of CNT / TiO₂ Photoelectrocatalytic Electrodes for Methlene Blue Degradation

Zhang, Feng-Jun,Chen, Ming-Liang,Oh, Won-Chun Materials Research Society of Korea 2008 한국재료학회지 Vol.18 No.11

In this study, two series of CNT/$TiO_2$ electrodes were prepared. The decrease of surface area compared with that of the pristine carbon nanotubes (CNTs) indicated the blocking of micropores on the surface of the CNTs; was further supported by scanning electron microscopy (SEM) and field emission SEM (FE-SEM) observations. The X-ray diffraction (XRD) results showed that the CNT/$TiO_2$ composites contained a mix of anatase and rutile forms of $TiO_2$ particles when the precursor was $TiO_2$ powder, whereas when the precursor was Ti ($OC_4H_7$) (TNB), the composites contained only the typical single and clear anatase $TiO_2$ particles. The energy dispersive X-ray spectroscopy (EDX) spectra showed the presence of C, O and Ti peaks for all samples. It was found that catalytic decomposition of methylene blue (MB) solution could be attributed to synthetic effects between the $TiO_2$ photocatalysis and electro-assisted CNTs network, and that photoelectrocatalytic oxidation increased with an increase of CNT composition. It was also found that the photoelectrocatalytic oxidation efficiency for MB is higher than that of photocatalytic oxidation. Moreover, the CNT/$TiO_2$ composites catalyst prepared by the impregnation method demonstrates higher photoelectrocatalytic activity than the mechanical mixture with the same CNT content.

A LINEAR MEASURING BRIDGE CIRCUIT WITH CONSIDERABLY WIDE RANGE

Chun, Zhang His,E, Chang Feng 대한전자공학회 1992 HICEC:Harbin International Conference on Electroni Vol.1 No.1

This paper describes an active linear measuring bridge with very wide range ΔR/R=(-100to+800)% and within the error limits-0.5%to+0.5%. The practical testing data and characteristics are given in this paper. There are substantial difference between the nonlinearity of the passive bridge and the so good linearity of the active bridge. The active linear measuring bridge with quite wide range is the very thing we need in automatic detecting instruments, testing and controlling systems by computers at present.

Characterization of CNT/TiO₂ Electrode Prepared Through Impregnation with TNB and Their Photoelectrocatalytic Properties

Feng Jun Zhang,Ming Liang Chen,Won Chun Oh 대한환경공학회 2009 Environmental Engineering Research Vol.14 No.1

In this study, we have prepared three kinds of carbon nanometer tube (CNT)/TiO₂ electrodes through impregnation with different concentration titanium n-butoxide (TNB) solution. The prepared electrodes were characterized with surface properties, structural crystallinity, elemental identification and photoelectrocatalytic activity. The N2 adsorption data showed that the composites had decreased surface area compared with the pristine CNT. This indicated the blocking of micropores on the surface of CNT, which was further supported by observation via SEM. XRD results showed patterns for the composites and a typical single and clear anatase crystal structure. The main elements such as C, O and Ti were existed for all samples from the EDX data. The catalytic efficiency of the developed electrode was evaluated by the photoelectrodegradation of methylene blue (MB). The positive potential applied in photoelectrocatalytic (PEC) oxidation was studied. It was found that photoelectrocatalytic (PEC) decomposition of MB solution could be attributed to combination effects between TiO₂ photocatalytic and CNT electro-assisted. Through the comparison between photocatalytic (PC) oxidation and photoelectrocatalytic (PEC) oxidation, it was found that the PEC oxidation efficiency for MB is higher than that of PC oxidation.

The effect of introduced method of titania and applied potential on the photoelectrocatalytic properties of CNT/TiO₂ electrodes

Zhang, Feng-Jun,Chen, Ming-Liang,Oh, Won-Chun The Korea Association of Crystal Growth 2010 韓國結晶成長學會誌 Vol.20 No.1

In this paper, three types of CNT/$TiO_2$ composite electrodes were prepared with different methods. The changes in XRD patterns showed that the Electrode A contained a mixed phase of anatase and rutile while the Electrode B and Electrode C contained a typical single and clear anatase crystal structure. From SEM micrographs, $TiO_2$ particles were adhered on the surface of the CNT network in the forms of small clusters. The results of chemical elemental analysis indicated that the main elements such as C, O and Ti were existed. The results demonstrated that the efficiency of photoelectrocatalytic (PEC) oxidation for methylene blue (MB) was higher than that of photocatalytic (PC) oxidation. There was a clear enhancement trend of the MB degradation using the prepared CNT/$TiO_2$ composite electrodes with an increase of applied potential. Finally, the prominent PEC activities of the CNT/$TiO_2$ composites could be attributed to combination effects of photo-degradation of $TiO_2$, electron assistant of CNT and function of applied potential.