Direct Determination of Uric Acid in Human Serum Samples Using Polypyrrole Nanoelectrode Ensembles

Yang, Guangming,Tan, Lin,Shi, Ya,Wang, Suiping,Lu, Xuxiao,Bai, Huiping,Yang, Yunhui Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.2

Polypyrrole (PPy) nanotubes have been synthesized by chemical oxidative polymerization of pyrrole within the pores of polycarbonate membrane using the technology of diffusion of solutes. The nanotubes array prepared by the proposed method can be considered as nanoelectrode ensembles (NEEs). An amperometric uric acid sensor based on PPy NEEs has been developed and used for determination of uric acid in human serum samples. The electrode can direct response to uric acid at potential of 0.60V vs. SCE with wide linear range of $1.52{\times}10^{-6}\;to\;1.54{\times}10^{-3}\;M.\;The\;detection\;limit\;is \;3.02{\times}10^{-7}$ M. This sensor has been used to determine uric acid in real serum samples. PPy NEEs is thought of as a good application in the foreground.

Direct Determination of Uric Acid in Human Serum Samples Using Polypyrrole Nanoelectrode Ensembles

Guangming Yang,Lin Tan,Ya Shi,Suiping Wang,Xuxiao Lu,Huiping Bai,Yunhui Yang 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.2

Polypyrrole (PPy) nanotubes have been synthesized by chemical oxidative polymerization of pyrrole within the pores of polycarbonate membrane using the technology of diffusion of solutes. The nanotubes array prepared by the proposed method can be considered as nanoelectrode ensembles (NEEs). An amperometric uric acid sensor based on PPy NEEs has been developed and used for determination of uric acid in human serum samples. The electrode can direct response to uric acid at potential of 0.60V vs. SCE with wide linear range of 1.52×10-6 to 1.54×10-3 M. The detection limit is 3.02×10-7 M. This sensor has been used to determine uric acid in real serum samples. PPy NEEs is thought of as a good application in the foreground.

Removal of Co(II) from aqueous solutions by sulfonated magnetic multi-walled carbon nanotubes

Juanjuan Yang,Yunhui Dong,Jun Li,Zhengjie Liu,Fanlian Min,Yueyun Li 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.11

Sulfonated magnetic multi-walled carbon nanotubes (SMMWCNTs) were applied in the sorption of Co(II) from aqueous solutions. The SMMWCNTs were prepared and characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR), and X-ray diffractometer (XRD) test. A large number of influencing factors to the sorption process were investigated, such as pH, ionic strength, contact time, cations, anions, humic acid (HA), fulvic acid (FA) and temperature. The results indicated that the Co(II) sorption was strongly controlled by the pH and ionic strength. Moreover, foreign anions, such as F−, Cl− and Br−, had an obvious effect on the sorption process, which depended on the electronegativity of the anions. On the other hand, cations restrained sorption strongly, such as Mg2+ and Ca2+. The existence of HA/FA enhanced sorption process at pH<8 while weakened at pH>8. As revealed by the sorption results, the Langmuir adsorption model was more favorable than the Freundlich adsorption model, and the pseudo-second-order model could fit the data much better than the pseudo-first-order. The thermodynamic analysis suggested that sorption was spontaneous and endothermic. What’s more, the stability experiments of the SMMWCNTs showed that SMMWCNTs could maintain excellent magnetic stability and dispersion stability. Thus, this SMMWCNTs sorbent was believed to be a promising material for the selective removal of Co(II) from heavy metal-containing wastewater.

국내산 낙엽송 소경각재의 허용응력 산출

김윤희(Yunhui Kim),신일중(Iljoong Shin),양정모(Jungmo Yang),장상식(Sangsik Jang) 한국가구학회 2012 한국가구학회지 Vol.23 No.2

Sustainable energy consumption and increasing CO₂ emissions stimulate Eco-friendly industry. Wood has positive various properties as alternative energy such as solar, wind and water. Wood provide lumber, pallet, paper, pulp and fuel through production process. Even Korea republic has 63.7% of forest rates, weather condition makes low forestry production capacity. For utilization of domestic small diameter log needs study mechanical properties. In this study, various properties tested on domestic Japanese Larch small diameter lumbers and make mechanical properties table for allowable stress calculation. Result of compressive test, allowable compressive stress is 13 ㎫. Allowable bending stress is 12 ㎫.

학습용 교구 개발을 위한 전동축의 모멘트와 토크 측정 방법 연구

양희주 ( Heejoo Yang ),최윤희 ( Yunhui Choi ),주진원 ( Jinwon Joo ) 충북대학교 건설기술연구소 2018 建設技術論文集 Vol.37 No.1

기계설계 과목에서는 주어진 설계 조건에 대한 각 기계요소들의 이론적인 내용이나 문제풀이 뿐 아니라, 이러한 기계요소로 구성된 기계 시스템에 대한 전체 설계와 작동 이해가 필요하다. 본 논문에서는 회전하는 축의 굽힘 모멘트와 토크를 측정할 수 있도록 교구를 개발하였다. 이를 위하여 스트레인게이지로 구성된 휘스톤 브리지의 출력을 측정하고, 슬립링을 이용하여 회전하는 축의 신호를 전달할 수 있도록 하였다. 축, 베어링, 기어, 모터 및 브레이크 요소를 사용한 기계 시스템이 설계되어 실제 작동하였다. 특성시험 결과 각 하중 단계에서 실험적인 굽힘 모멘트 값은 이론적인 굽힘 모멘트 값과 잘 일치하였고, 특히 기어비가 1:2인 경우에는 0.5% 이내로 아주 잘 일치하였다. 기어비가 1:3.2인 경우에도 3% 이내로 잘 일치하였다. 실험적인 측정 토크는 이론적인 토크 값에 비해서 기어비가 1:2인 경우에는 약 26%, 기어비가 1.32인 경우에는 약 30%의 오차가 발생 하였다. In the Mechanical Design course, not only the theoretical concept and problem solving of each mechanical element for a given design condition, but also the overall design and operation understanding of a mechanical system composed of these mechanical elements is required. In this paper, we developed a educational equipment to measure the bending moment and torque of rotating shafts. For this purpose, the output of a Wheatstone bridge, which consists of strain gauges, was measured and the signal of the rotating axis was transmitted using a slip ring. Mechanical systems using shafts, bearings, gears, motors and brake elements have been designed and operated in practice. As a result of the characteristic test, the experimental bending moment values at the respective loading stages are in good agreement with the theoretical bending moment values, and especially within the range of 0.5% when the gear ratio is 1: 2. When the gear ratio is 1: 3.2, the output is well within 3%. Experimental measurement torque is about 26% when the gear ratio is 1: 2 and about 30% when the gear ratio is 1:3.2 as compared with the theoretical torque value.

Determination of Palladium in Water Samples Using Cloud Point Extraction Coupled with Laser Thermal Lens Spectrometry

Han, Quan,Huo, Yanyan,Yang, Na,Yang, Xiaohui,Zhai, Yunhui,Zhang, Qianyun Korean Chemical Society 2015 대한화학회지 Vol.59 No.5

A preconcentration procedure for determination of palladium by laser thermal lens spectrometry (TLS) is proposed. It is based on cloud point extraction of palladium(II) ions as 2-(3,5-dichloro-2-pyridylazo)-5-dimethylaminoaniline (3,5-diCl-PADMA) complexes using octylphenoxypolyethoxyethanol (Triton X-114) as surfactant. The effects of various experimental conditions such as pH, concentration of ligand and surfactant, equilibration temperature and time on cloud point extraction were studied. Under the optimized conditions, the calibration graph was linear in the range of 0.15~6 ng mL⁻¹, and the detection limit was 0.04 ng mL⁻¹ with an enrichment factor of 22. The sensitivity was enhanced by 846 times when compared with the conventional spectrophotometric method. The recovery of palladium was in the range of 96.6%~104.0%. The proposed method was applied to the determination of palladium in water samples.

Amperometric Morphine Detection Using Pt-Co Alloy Nanowire Array-modified Electrode

Manlan Tao,Feng Xu,Yueting Li,Quanqing Xu,Yanbing Chang,Zaisheng Wu,Yunhui Yang 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.7

Pt-Co alloy nanowire array was directly synthesized by electrochemical deposition with polycarbonate template at ‒1.0V and subsequent chemical etching of the template. The use of Pt-Co alloy nanowire array-modified electrode (Pt-Co NAE) for the determination of morphine (MO) is described. The morphology of the Pt-Co alloy nanowire array has been investigated by scanning electron microscopy (SEM) and energy disperse X-ray spectroscopy (EDS) analysis), respectively. The resulting Pt-Co NAE offered a linear amperometric response for morphine ranging from 2.35 × 10‒5 to 2.39 × 10‒3 M with a detection limit of 7.83 × 10‒6 M at optimum conditions. This sensor displayed high sensitivity and long-term stability.

Evaluation and modeling of methyl green adsorption from aqueous solutions using loofah fibers

Xiaonan Tang,Yueyun Li,Runhai Chen,Fanlian Min,Juanjuan Yang,Yunhui Dong 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.1

Loofah fiber, an economical adsorbent material, was first developed for the methyl green (MG) removalfrom aqueous solutions. The loofah fibers were characterized by SEM, FTIR, N2-BET and the potentiometric titration. The pH, contact time and temperature were examined extensively. The adsorption of MG on loofah fiber increasedvery quickly in the pH range 3.0 to 7.0, remaining a high level at pH>7.0. The kinetics of adsorption of MG on theloofah fiber was proved to coincide with pseudo-second-order kinetic models (r2>0.99) very well. Langmuir isothermwas demonstrated to fit the experimental data better than Freundlich isotherm model. Monolayer adsorption capacityincreased with the increase of temperature. Thermodynamic constants were evaluated, and the results indicated thatMG adsorption onto loofah fiber was feasible, spontaneous and endothermic. The high removal efficiency of MG onloofah fiber suggested that the loofah fiber was suitable material in MG pollution cleanup.

A Social Motivation-aware Mobility Model for Mobile Opportunistic Networks

( Sen Liu ),( Xiaoming Wang ),( Lichen Zhang ),( Peng Li ),( Yaguang Lin ),( Yunhui Yang ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.8

In mobile opportunistic networks (MONs), human-carried mobile devices such as PDAs and smartphones, with the capability of short range wireless communications, could form various intermittent contacts due to the mobility of humans, and then could use the contact opportunity to communicate with each other. The dynamic changes of the network topology are closely related to the human mobility patterns. In this paper, we propose a social motivation-aware mobility model for MONs, which explains the basic laws of human mobility from the psychological point of view. We analyze and model social motivations of human mobility mainly in terms of expectancy value theory and affiliation motivation. Furthermore, we introduce a new concept of geographic functional cells, which not only incorporates the influence of geographical constraints on human mobility but also simplifies the complicated configuration of simulation areas. Lastly, we validate our model by simulating three real scenarios and comparing it with reality traces and other synthetic traces. The simulation results show that our model has a better match in the performance evaluation when applying social-based forwarding protocols like BUBBULE.