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SIMPLE AND CATALYST-FREE SYNTHESIS OF SILICON OXIDE NANOWIRES AND NANOCOILS
XINQI CHEN,로드니루오프 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2007 NANO Vol.2 No.2
In this paper, a simple method for synthesizing SiOx nanowires and nanocoils is presented. Si substrates with an oxide layer were placed in a tube furnace exposed to temperatures ranging from 900°C to 1200°C for a few hours under a mixture of flowing Ar and H2 gas maintained at ambient pressure. Nanowires were grown from the surface when the furnace temperature was above 1000°C and a high yield could be achieved at 1100°C. SiOx nanocoils have also been observed and the sample treated at 1000°C had the highest concentration of them. TEM images show that the nanowires and the nanocoils have an amorphous structure and analysis of EDX spectra (obtained in the TEM) shows that x varies from 1.2 to 2.0. The mechanism of growth is discussed.
( Shuai Zhang ),( Xinqi Zhang ),( Yu Cheng ),( Naiqiao Ning ),( Yinsheng Lin ),( Liang Chen ) 아시아스포츠융합과학회 2021 Asia Pacific Journal of Applied Sport Sciences Vol.2 No.3
PURPOSE This research establishes a reasonable research model to investigate the relationship between the perceived risks, mitigating factors, and travel intentions of potential visitors to the Olympic Games under the COVID-19 epidemic environment. And examine the mediating role of mitigating factors between perceived risk and travel intention. METHOD This study conducted two online surveys with Chinese athletes as the survey subject, divided into two samples for the Tokyo Olympics and the Beijing Olympics. The data analysis process is divided into two stages. In the first stage, confirmatory factor analysis (CFA) is used to test the reliability and validity of the scale. In the second stage, structural equation modeling (SEM) analysis is used to test the proposed hypothesis. Finally, the data test results of the two samples are compared. RESULT After the CFA test, the data fit well with the model, and the model had good combination reliability and convergence validity. On this basis, a structural equation model was established, and the mediation validity of the model was tested. CONCLUSION The results show that risk perception has a significant effect on mitigating factors, and mitigating factors have very significant positive effects on behavioral intentions. Mitigating factors mediate between risk perception and behavioral intentions.
Haiping Li,Xinqi Guo,Xun Zhu,Yina Chen,Limin Zhang,Jiaqi Lu,Qiuting Qian 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.2
The aim of this study was to evaluate the effect of ultrahigh pressure processing (UHP) of 200, 300, 400, 500, 600 and 700 MPa for 20, 40 and 30 min on physicochemical and bioactive properties of the insoluble dietary fiber Pholiota nameko (PN-IDF). The results revealed that UHP were capable of decreasing the particle size of PN-IDF and binding phenolic content. Moreover, UHP technique had an improving effect on the bioaccessible phenolic content, the water-holding capacity, the oil-holding capacity and the nitrite ion adsorption capacity. Further, UHP technique presented a promoting effect on the antioxidant activity by scavenging ABTS or DPPH free radicals and increasing reducing power, and the anti-inflammatory activity by inhibiting carrageenan-induced paw edema on PN-IDF. Overall, this study well proved that UHP technology could improve the physicochemical and functional quality of PN-IDF, which could be used as a promising green technique for functional food ingredients processing.
( Min Shen ),( Xin Ju ),( Xinqi Xu ),( Xuemei Yao ),( Liangzhi Li ),( Jiajia Chen ),( Cuiying Hu ),( Jiaolong Fu ),( Lishi Yan ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.7
In this study, we attempted to find new and efficient microbial enzymes for producing rare sugars. A ribose-5-phosphate isomerase B (OsRpiB) was cloned, overexpressed, and preliminarily purified successfully from a newly screened Ochrobactrum sp. CSL1, which could catalyze the isomerization reaction of rare sugars. A study of its substrate specificity showed that the cloned isomerase (OsRpiB) could effectively catalyze the conversion of L-rhamnose to L-rhamnulose, which was unconventional for RpiB. The optimal reaction conditions (50oC, pH 8.0, and 1 mM Ca<sup>2+</sup>) were obtained to maximize the potential of OsRpiB in preparing L-rhamnulose. The catalytic properties of OsRpiB, including K<sub>m</sub>, K<sub>cat</sub>, and catalytic efficiency (K<sub>cat</sub>/K<sub>m</sub>), were determined as 43.47 mM, 129.4 sec<sup>-1</sup>, and 2.98 mM/sec. The highest conversion rate of L-rhamnose under the optimized conditions by OsRpiB could reach 26% after 4.5 h. To the best of our knowledge, this is the first successful attempt of the novel biotransformation of L-rhamnose to L-rhamnulose by OsRpiB biocatalysis.
RIPENING OF SILVER NANOPARTICLES ON CARBON NANOTUBES
LIYING ZHU,GANHUA LU,SHUN MAO,JUNHONG CHEN,DMITRIY A. DIKIN,XINQI CHEN,로드니루오프 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2007 NANO Vol.2 No.3
An electrostatic-force-directed-assembly technique was used to coat multiwalled carbon nano-tubes (MWCNTs) with aerosol Ag nanoparticles produced from a mini-arc plasma source. The deposition of Ag nanoparticles onto CNTs was confirmed by transmission electron microscopy (TEM), high-resolution TEM, scanning electron microscopy, and X-ray photoelectron spectroscopy. Ripening of Ag nanoparticles on CNTs was observed via successive TEM imaging after heating the nanoparticle–nanotube hybrid structures in air to three different temperatures ranging from 100°C to 300°C. With temperatures at and above 200°C, the areal density of Ag nanoparticles decreased and the average particle size increased. In particular, migration and coalescence of Ag nanoparticles have been observed at this relatively low temperature, which suggests a van der Waals nanoparticle–nanotube interaction.
Bond-Orientational Order in Melting of Colloidal Crystals
Xin Qi,Yong Chen,Yan Jin,Yao-Hui Yang 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.4
Using Brownian dynamics simulation, we study the orientational order in the melting transition of a colloidal system with a `soft' Yukawa potential. The bond-orientational order parameter ⓒ6 and the bond-orientational order function gB(r) are calculated in two-dimensional systems. We found that a two-stage transition and a hexatic phase indeed exist in two-dimensional melting, which is consistent with the prediction of the Kosterlitz-Thouless-Halperin-Nelson-Young theory. For comparing with the melting process in three-dimensional systems, we introduce the probability distribution of the single-particle local-order parameter. Based on extensive simulations, the break- down of local order is qualitatively suggested only to occur on the fractional part of the colloidal system for the two-dimensional melting, but in three-dimensional melting, that breakdown takes place on the whole system at the same time.F