Phenylalanine sensing based on surface plasmon resonance.

Chen, Hongxia,Lee, Jaebeom,Kim, Sung-Hoon,Kim, Jae-Ho,Koh, Kwangnak American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.12

<P>A phenylalanine sensing system was constructed with photochromic spiroxazine derivative via surface plasmon resonance (SPR). Recognition-functional spiroxazine monolayer was formed on Au surface by self-assembly. After spectroscopic characterizations of monolayer, various concentrations of d- and l-phenylalanine were employed as analytes on UV addressable ring-opened spiroxazine monolayer. The different SPR angle shift derived from interaction between d- and l-phenylalanine and spiroxazine monolayer can be explained by the different dipole moment of ionic complexes. Computer simulations using Molecular Orbital PACkage AM1 approximation reinforced the reliability of the experimental results. To confirm the long-time stability of spiroxazine monolayer, we measured SPR response of spiroxazine monolayer with repetitive UV-on and off. These experimental results suggest that it can be applicable to simple analysis of interaction between zwitterionic recognition-functional molecule and analyte.</P>

Surface plasmon resonance investigation of a copolymer containing spiroxazine.

Chen, Hongxia,Lee, Jaebeom,Cho, Chae-Ryong,Kim, Sung-Hoon,Kim, Jae-Ho,Koh, Kwangnak American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.12

<P>Spiroxazines are a class of photochromic compounds whose molecular structures are alterable upon exposure to UV/visible light. The typical reaction of spiroxazines is the conversion between the non-polar ring-closure form and polar ring-open form. In this work, copolymer of 1,6-heptadiyne derivatives containing a spiroxazine was used as photochromic material. Precise photochromic properties of the copolymer's thin-film were evaluated through measuring dielectric constant, optical constant and thickness by surface plasmon resonance (SPR) with multi-solvent approach. The change in structure under UV-light irradiation is accompanied by increase of dielectric constant. However, dielectric constant and UV-induced thickness change of the photochromic polymer thin-film are independent of film thickness.</P>

A fatigue and low-energy shock-based approach to predict fatigue life

Hongxia Chen,Yunxia Chen,Yi Yang 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.10

A product that is characterized by fatigue-induced failure always suffers from complex fatigue loads, and the damage caused by fatigueloads accumulates with time. The existence of shocks not only directly increases the risk of failure but also affects the magnitude ofdamage caused by fatigue loads. This study analyzes the reliability of a product when fatigue loads and shocks are both involved. Thefeatures of fatigue damage and shock damage are investigated, and the coupling relationship between them is discussed. With assumptionsof high cycle fatigue and low-energy shocks, the effect of shocks on fatigue damage is expressed as the degradation of the ultimatestrength of the product. An overall reliability model with fatigue and shock failures is developed. Two conditions are considered for thereliability model: shocks with fixed period and shocks with a homogeneous Poisson process. Three important cumulative damage theoriesare adopted. An engineering case of actuator cylinder is provided to demonstrate the proposed approach.

Nanoassembly of CdTe nanowires and Au nanoparticles: pH dependence and reversibility of photoluminescence

이재범,Hongxia Chen,고광락,장철훈,김철민,김수형 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.2

Radial organized nanohybrids that are composed of Au nanoparticles (NPs) surrounding CdTe nanowires (NWs) via bioconjugation of streptavidin (SA) and D-biotin (B) were prepared to compare with the non-conjugated NWs. Two respective NW-containing hybrids with/without Au bioconjugation presented the same pH dependence except for photoluminescence (PL) reversibility. It would be explained that the chemical modification of NW surface can be retarded due to the geometric hindrance of acidic fluids in nanoscale regime and the loosely encapsulated Au NPs on NWs assisted to induce the luminescence recovery from collective resonance of excitons and plasmons in nanohybrids.

Proteome alterations of reverse photoperiod-sensitive genic male sterile rice (Oryza sativa L.) at fertility transformation stage

Zhen Chen,Han-lai Zeng,Haixia Li,Xueli Ma,Hongxia Dong,Dong Ma 한국유전학회 2014 Genes & Genomics Vol.36 No.6

The two-line system has been widely used inhybrid rice seed production, and the reverse photoperiodsensitivegenic male sterile line is a new germplasm withan opposite phenotype compared with normal photoperiodsensitivegenic male sterile rice. To better understand themolecular mechanisms of fertility regulation in reversephotoperiod-sensitive genic male sterile rice, a comparativeproteomic approach was used to analyze the proteinprofiles of three different tissues (young panicles, flagleaves and leaf sheaths) of D52S during the sensitive periodof pollen fertility transformation under sterile and fertileconditions. By quantitative analysis, 66 protein spotswere identified to be significantly changed in the threetissues. Bioinformatics analyses revealed that in sterilerice, a number of proteins involved in lignin-flavonoidbiosynthesis pathway were down-accumulated in panicles. The majority of proteins associated with energy metabolismwere down-accumulated in leaf sheaths while theproteins up-accumulated in leaves and leaf sheaths wereexclusively photosynthesis and defense related. Based onthe proteomics data, a short-day induced male sterilityprotein network was proposed. In addition, the genes ofselected protein spots were further analyzed by qPCR. These findings provide data for better understanding theregulation of pollen fertility in reverse photoperiodsensitivegenic male sterile rice, which could assist in thedevelopment of practical reverse photoperiod-sensitivegenic male sterile rice for large-scale crop breedingprograms.

A Possible Merge of FRET and SPR Sensing System for Highly Accurate and Selective Immunosensing

Jaebeom Lee,Hongxia Chen,이재욱,Fangfang Sun,Cheol-Min Kim,Chulhun L. Chang,Kwangnak Koh 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.12

Immuno-sensing for high accurate and selective sensing was performed by fluorescence spectroscopy and surface plasmon resonance (SPR), respectively. Engineered assembly of two fluorescent quantum dots (QDs) with bovine serum albumin (BSA) and anti-BSA was fabricated in PBS buffer for fluorescence analysis of fluorescence resonance energy transfer (FRET). Furthermore, the same bio-moieties were immobilized on Au plates for SPR analysis. Naturally- driven binding affinity of immuno-moieties induced FRET and plasmon resonance angle shift in the nanoscale sensing system. Interestingly, the sensing ranges were uniquely different in two systems: e.g., SPR spectroscopy was suitable for highly accurate analysis to measure in the range of 10-15∼-10 ng/mL while the QD fluorescent sensing system was relatively lower sensing ranges in 10-10∼- 6 ng/mL. However, the QD sensing system was larger than the SPR sensing system in terms of sensing capacity per one specimen. It is, therefore, suggested that a mutual assistance of FRET and SPR combined sensing system would be a potentially promising candidate for high accuracy and reliable in situ sensing system of immune-related diseases.

Carbon Nanotubes Grafted with Hyperbranched Triazine Compounds

Tingting Li,HONGXIA YAN,Tianye Liu,Chao Liu,Zhengyan Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.1

In order to improve the dispersibility of carbon nanotubes (CNTs) in the resin matrix, CNTs grafted with hyperbranched triazine compound (HPTC–CNTs) was produced by four generations condensation reaction using cyanuric chloride and hexamethylenediamine. Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), UV-Vis spectroscopy (UV-Vis) and transmission electron microscopes (TEM) were used to characterize the obtained HPTC–CNTs. The FTIR, XPS, UV-Vis and TEM analysis showed that CNTs had been successfully grafted with HPTC. The TGA showed that the content of HPTC on the surface of CNTs was about 58 wt.%. And the HPTC–CNTs had good dispersion both in water and acetone.

Life Prediction and Long-Term Durability of Coated Steel Bars in Magnesium Oxychloride Concrete

Penghui Wang,Hongxia Qiao,Kefan Chen,Yuanke Li,Qiong Feng 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.7

The solution to the problem of corrosion of the steel bars in magnesium oxychloride cement concrete (MOCC) is to apply a coating that protects the steel. To investigate the coating’s long-term protective effect on the steel, a solution immersion accelerated corrosion test was carried out on coated reinforced MOCC for up to 2,160 days. Electrochemical tests were conducted every 90 days to measure the polarization curve and AC impedance during the steel bars’ corrosion process. Then, the corrosion current density that characterizes the corrosion of a coated steel bar was used as a degradation index, and the time to the coated steel bar’s corrosion was predicted based on the Wiener function. It was concluded that after 2,160 days of solution immersion, the coated steel bars’ corrosion current density was 0.063 μA·cm−2, indicating that the coating protected the steel bars in MOCC from corrosion well. Thdroughout the immersion process, the specimen’s corrosion current density showed a steady and increasing trend, and its polarization impedance showed a volatile growth trend. The degradation of the coated steel bars also obeyed the Wiener degradation process, and the bars reached a severely rusted state at 21,800d with a corrosion time of R0.6(t) is 10,650d.

Environmental Issues on End-of-Life Battery from Next-Generation Vehicles in Japan

( Jeongsoo Yu ),( Xiaoyue Liu ),( Hongxia Chen ) 한국폐기물자원순환학회 2022 ISSE 초록집 Vol.2022 No.-

Manufacture and recycling of vehicle batteries in China, Japan and Korea have drawn more and more attention, the types of batteries in different countries are not uniform, so it is difficult to ensure the recovery of rare metals. To meet the increasing manufacturing demand of Next-Generation Vehicles (NGVs), the importance of reuse and recycling of vehicle batteries is also increasing. This research gives an overview of the popularization of NGVs, as well as the status and topics of reuse and recycling of vehicle batteries in Japan. Japanese government and auto makers have already established a battery recycling system; however, NiMH batteries and LIBs are usually exported along with massive secondhand vehicles. In NiMH batteries LCA case, the reuse and/or recycling of EoL NiMH batteries will bring more environmental burdens than the nonrecycling scenario. However, by reusing or recycling EoL NiMH batteries, we can avoid manufacturing new NiMH batteries or recycle certain metal resources. The reuse policy for EoL NiMH batteries should be implemented and the EoL NiMH batteries treated, as soon as possible in Japan. In addition, there appear to be a vast number of low-capacity waste NiMH battery exports from Japan to developing countries. These batteries will lose their function completely soon after being exported and may eventually be inappropriately treated.

Ultrafast dynamics control on ablation of Cu using shaped femtosecond pulse trains

Deng Jiannan,Qi Hongxia,Liu Xinyi,Li Xiaoyi,Tong Qiunan,Lian Zhenzhong,Li Juan,Bo Jinqiu,Fei Dehou,Chen Zhou,Hu Zhan 한국물리학회 2021 Current Applied Physics Vol.26 No.-

The ablation processes of Cu film are investigated using temporal shaped femtosecond pulse trains. The depth is modulated by changing the number and interval of the sub-pulses. The underlying ultrafast dynamic processes are discussed based on plasma shielding and electron multiple heating mechanisms. When the sub-pulse interval is less than 0.4 ps electron multiple heating is the dominant mechanism, while the plasma shielding dominates the subsequent ablation processes when the sub-pulse interval is larger than 0.4 ps. The curve of depth obtained by three pulse trains shows more significant oscillation as the function of sub-pulse interval under the lowfluence. We propose that the oscillation of depth is due to the coherent phonon oscillation excited by the pulse train. The study provides a basis for giving insight into the ultrafast dynamics for improving micromachining and nano-fabrications using shaped femtosecond pulse trains.