Activation of formyl CH and hydroxyl OH bonds in HMF by the CuO(1 1 1) and Co₃O₄(1 1 0) surfaces: A DFT study

Ren, Jun,Song, Kai-he,Li, Zhenhuan,Wang, Qiang,Li, Jun,Wang, Yingxiong,Li, Debao,Kim, Chan Kyung Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.456 No.-

<P><B>Abstract</B></P> <P>The first principle calculations with on-site Coulomb repulsion U terms were carried out to investigate the 5-hydroxymethylfurfural (HMF) adsorption on the CuO(1 1 1) and Co<SUB>3</SUB>O<SUB>4</SUB>(1 1 0) surfaces, two widely used oxidation catalysts. The adsorption of HMF molecule is energetically favoured in both cases, and HMF is more inclined to bridge adsorption via hydroxyl and formyl groups binding with surface O and metal sites. Moreover, the adsorption energy relies on both the coordination type of surface lattice oxygen to which the H atom binds and the formation of H-bond involving hydroxyl and formyl groups on the adsorbed HMF. Also, the hydroxyl OH bond breaking is very easy and is likely to be the first step in HMF oxidation, and then the OH insertion reaction to produce 2,5-furandicarboxylic acid (FDCA). The corresponding experimental results also show that the CuO and Co<SUB>3</SUB>O<SUB>4</SUB> surfaces are promising candidate catalysts.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CuO(1 1 1) and Co<SUB>3</SUB>O<SUB>4</SUB>(1 1 0) surfaces catalyze the oxidation of 5-hydroxymethylfurfural (HMF). </LI> <LI> Initial binding was formed through bridged-adsorption with O atoms in HMF. </LI> <LI> Oxidation reaction proceeds through the OH bond breaking pathway. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Schematic potential energy diagram for the formyl CH and hydroxyl OH bonds of HMF dissociation on CuO(1 1 1) and Co<SUB>3</SUB>O<SUB>4</SUB>(1 1 0) surfaces. Obviously, the hydroxyl OH bond breaking is easier than that of the formyl CH bond on the two surfaces, which indicates the first step of oxidation of HMF to FDCA should be hydroxyl OH bond breaking.</P> <P>[DISPLAY OMISSION]</P>

Observational study of wind characteristics from 356-meter-high Shenzhen Meteorological Tower during a severe typhoon

Yinghou He,Qiu-Sheng Li,Pakwai Chan,Li Zhang,Honglong Yang,Lei Li 한국풍공학회 2020 Wind and Structures, An International Journal (WAS Vol.30 No.6

The characteristics of winds associated with tropical cyclones are of great significance in many engineering fields. This paper presents an investigation of wind characteristics over a coastal urban terrain based on field measurements collected from multiple cup anemometers and ultrasonic anemometers equipped at 13 height levels on a 356-m-high meteorological tower in Shenzhen during severe Typhoon Hato. Several wind quantities, including wind spectrum, gust factor, turbulence intensity and length scale as well as wind profile, are presented and discussed. Specifically, the probability distributions of fluctuating wind speeds are analyzed in connection with the normal distribution and the generalized extreme value distribution. The von Karman spectral model is found to be suitable to depict the energy distributions of three-dimensionally fluctuating winds. Gust factors, turbulence intensity and length scale are determined and discussed. Moreover, this paper presents the wind profiles measured during the typhoon, and a comparative study of the vertical distribution of wind speeds from the field measurements and existing empirical models is performed. The influences of the topography features and wind speeds on the wind profiles were investigated based on the field-measured wind records. In general, the empirical models can provide reasonable predictions for the measured wind speed profiles over a typical coastal urban area during a severe typhoon.

Field measurements of wind characteristics over hilly terrain within surface layer

He, Y.C.,Chan, P.W.,Li, Q.S. Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.19 No.5

This paper investigates the topographic effects on wind characteristics over hilly terrain, based on wind data recorded at a number of meteorological stations in or near complex terrain. The multiply data sources allow a more detailed investigation of the flow field than is normally possible. Vertical profiles of mean and turbulent wind components from a Sodar profiler were presented and then modeled as functions of height and wind speed. The correlations between longitudinal and vertical wind components were discussed. The phenomena of flow separation and generation of vortices were observed. The distance-dependence of the topographic effects on gust factors was revealed subsequently. Furthermore, the canyon effect was identified and discussed based on the observations of wind at a saddle point between two mountain peaks. This study aims to further understanding of the characteristics of surface wind over rugged terrain. The presented results are expected to be useful for structural design, prevention of pollutant dispersion, and validation of CFD (computational fluid dynamics) models or techniques over complex terrains.

Wind profiles of tropical cyclones as observed by Doppler wind profiler and anemometer

He, Y.C.,Chan, P.W.,Li, Q.S. Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.17 No.4

This paper investigates the vertical profiles of horizontal mean wind speed and direction based on the synchronized measurements from a Doppler radar profiler and an anemometer during 16 tropical cyclones at a coastal site in Hong Kong. The speed profiles with both open sea and hilly exposures were found to follow the log-law below a height of 500 m. Above this height, there was an additional wind speed shear in the profile for hilly upwind terrain. The fitting parameters with both the power-law and the log-law varied with wind strength. The direction profiles were also sensitive to local terrain setups and surrounding topographic features. For a uniform open sea terrain, wind direction veered logarithmically with height from the surface level up to the free atmospheric altitude of about 1200 m. The accumulated veering angle within the whole boundary layer was observed to be $30^{\circ}$. Mean wind direction under other terrain conditions also increased logarithmically with height above 500 m with a trend of rougher exposures corresponding to lager veering angles. A number of empirical parameters for engineering applications were presented, including the speed adjustment factors, power exponents of speed profiles, and veering angle, etc. The objective of this study aims to provide useful information on boundary layer wind characteristics for wind-resistant design of high-rise structures in coastal areas.

원적외선 방사체를 이용한 발효녹차의 건조특성

리혁 ( He Li ),한충수 ( Chung Su Han ),김유호 ( You Ho Kim ),최종민 ( Jong Min Choi ),강태환 ( Tae Hwan Kang ),조성찬 ( Sung Chan Cho ) 한국산업식품공학회 2005 산업 식품공학 Vol.9 No.3

Inhibition of HBV replication and gene expression in vitro and in vivo with a single AAV vector delivering two shRNA molecules

( Zhi Li ),( Ming Liang He ),( Hong Yao ),( Qing Ming Dong ),( Yang Chao Chen ),( Chu Yan Chan ),( Bo Jian Zheng ),( Kwok Yung Yuen ),( Ying Peng ),( Qiang Sun ),( Xiao Yang ),( Marie C. Lin ),( Josep 생화학분자생물학회 2009 BMB Reports Vol.42 No.1

Field measurements of wind characteristics over hilly terrain within surface layer

Y.C. He,Q. S. Li,P.W. Chan 한국풍공학회 2014 Wind and Structures, An International Journal (WAS Vol.19 No.5

This paper investigates the topographic effects on wind characteristics over hilly terrain, based on wind data recorded at a number of meteorological stations in or near complex terrain. The multiply data sources allow a more detailed investigation of the flow field than is normally possible. Vertical profiles of mean and turbulent wind components from a Sodar profiler were presented and then modeled as functions of height and wind speed. The correlations between longitudinal and vertical wind components were discussed. The phenomena of flow separation and generation of vortices were observed. The distance-dependence of the topographic effects on gust factors was revealed subsequently. Furthermore, the canyon effect was identified and discussed based on the observations of wind at a saddle point between two mountain peaks. This study aims to further understanding of the characteristics of surface wind over rugged terrain. The presented results are expected to be useful for structural design, prevention of pollutant dispersion, and validation of CFD (computational fluid dynamics) models or techniques over complex terrains.

Wind profiles of tropical cyclones as observed by Doppler wind profiler and anemometer

Y.C. He,Q. S. Li,P.W. Chan 한국풍공학회 2013 한국풍공학회지 Vol.17 No.4

This paper investigates the vertical profiles of horizontal mean wind speed and direction based on the synchronized measurements from a Doppler radar profiler and an anemometer during 16 tropical cyclones at a coastal site in Hong Kong. The speed profiles with both open sea and hilly exposures were found to follow the log-law below a height of 500 m. Above this height, there was an additional wind speed shear in the profile for hilly upwind terrain. The fitting parameters with both the power-law and the log-law varied with wind strength. The direction profiles were also sensitive to local terrain setups and surrounding topographic features. For a uniform open sea terrain, wind direction veered logarithmically with height from the surface level up to the free atmospheric altitude of about 1200 m. The accumulated veering angle within the whole boundary layer was observed to be 30°. Mean wind direction under other terrain conditions also increased logarithmically with height above 500 m with a trend of rougher exposures corresponding to lager veering angles. A number of empirical parameters for engineering applications were presented, including the speed adjustment factors, power exponents of speed profiles, and veering angle, etc. The objective of this study aims to provide useful information on boundary layer wind characteristics for wind-resistant design of high-rise structures in coastal areas.

Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO₂ addition

Hong Zhang, Shi,Xi Li, Ming,Hong Yoon, Jae,Yul Cho, Tong,Zhu He, Yi,Gyu Lee, Chan Elsevier 2008 SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS Vol.9 No.3

<P>Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO<SUB>2</SUB> (<I>m</I>-CeO<SUB>2</SUB>) and also 1.5% and 3.0% nano-size CeO<SUB>2</SUB> (<I>n</I>- CeO<SUB>2</SUB>) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO<SUB>2</SUB> laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of <I>m</I>- and <I>n</I>- CeO<SUB>2</SUB> powders to NBA (<I>m</I>- and <I>n</I>- CeO<SUB>2</SUB> /NBA) have been investigated. The results showed that a smooth coating was prepared under suitable processing parameters (<I>P</I>= 2.0 kW, <I>V</I>= 180 mm min<SUP>- 1</SUP>) by adding 1.5% <I>n</I>- CeO<SUB>2</SUB>. In addition to the primary phases of γ-Ni, Cr<SUB>23</SUB> C<SUB>6</SUB> and Ni<SUB>3</SUB> B in the Ni-base alloy coating, CeNi<SUB>3</SUB> was formed in Ni-base alloy coatings with both <I>n</I>- CeO<SUB>2</SUB> and <I>m</I>-CeO<SUB>2</SUB> particles, and CeNi<SUB>5</SUB> appeared in the coating upon decreasing the size of CeO<SUB>2</SUB> particles. Well-developed dendrites were observed in the Ni-base alloy coating; directional dendrites grew at the interface in the coating upon the addition of <I>m</I>-CeO<SUB>2</SUB>, whereas fine and multioriented dendrites grew upon decreasing the size of CeO<SUB>2</SUB> particles to the nanoscale. Actinomorphic dendrites and compact equiaxed dendrites grew from the interface to near the surface upon increasing the content of <I>n</I>- CeO<SUB>2</SUB> from 1.5 to 3.0%. In strongly acidic HNO<SUB>3</SUB> solution, the severe corrosion of dendrites occurred and there were many corrosion pits in the Ni-base alloy coating; intercrystalline corrosion also has a dominant role upon the addition of <I>m</I>-CeO<SUB>2</SUB>, whereas uniform corrosion occurs in the coating as the size of CeO<SUB>2</SUB> particles is decreased to nanoscale.</P>

Infection and Immune Response in the Nematode Caenorhabditis elegans Elicited by the Phytopathogen Xanthomonas

( Yan Ii Bai ),( De Juan Zhi ),( Chan He Li ),( Dong Iing Liu ),( Ju An Zhang ),( Jing Ti An ),( Xin Wang ),( Hui Ren ),( Hong Yu Li ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.9

Xanthomonas oryzae pv. oryzae (Xoo) strains are plant pathogenic bacteria that can cause serious blight of rice, and their virulence towards plant host is complex, making it difficult to be elucidated. Caenorhabditis elegans has been used as a powerful model organism to simplify the host and pathogen system. However, whether the C. elegans is feasible for studying plant pathogens such as Xoo has not been explored. In the present work, we report that Xoo strains PXO99 and JXOIII reduce the lifespan of worms not through acute toxicity, but in an infectious manner; pathogens proliferate and persist in the intestinal lumen to cause marked anterior intestine distension. In addition, Xoo triggers (i) the p38 MAPK signal pathway to upregulate its downstream C17H12.8 expression, and (ii) the DAF-2/DAF-16 pathway to upregulate its downstream gene expressions of mtl-1 and sod-3 under the condition of daf-2 mutation. Our findings suggest that C. elegans can be used as a model to evaluate the virulence of Xoo phytopathogens to host.