Effect of surface modification layer thickness on the gas sensitivity of SnO2 films

Y.H. Xiong,L. Wang,X.Y. Wei,G.R. Qin,C.H. Mao,J. Du 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.4

Nickel was used as a surface modification material to enhance the gas-sensing properties of SnO2 films. The thickness of the Ni modification layer was controlled by the sputtering time. The surface morphology and surface chemical composition of the surface modification layers of different thicknesses were analyzed by Field Emission Scanning Electron Microscopy (FESEM) and X-ray Photoelectron Spectroscopy (XPS), respectively. The gas sensitivity to clean air with a low hydrogen concentration of 1000 ppm of the modified tin dioxide thin films was investigated at temperatures from 20oC to 100oC. The results show that the thickness of the modification layer plays an important role in the enhancement of the gas-sensing properties and surface electric properties of SnO2 films. A Ni modification layer with a thickness of 50 nm on the surface of a SnO2 film can improve the hydrogen gas sensitivity of a SnO2 film up to 112%, and reduce the response time to 80s. Nickel was used as a surface modification material to enhance the gas-sensing properties of SnO2 films. The thickness of the Ni modification layer was controlled by the sputtering time. The surface morphology and surface chemical composition of the surface modification layers of different thicknesses were analyzed by Field Emission Scanning Electron Microscopy (FESEM) and X-ray Photoelectron Spectroscopy (XPS), respectively. The gas sensitivity to clean air with a low hydrogen concentration of 1000 ppm of the modified tin dioxide thin films was investigated at temperatures from 20oC to 100oC. The results show that the thickness of the modification layer plays an important role in the enhancement of the gas-sensing properties and surface electric properties of SnO2 films. A Ni modification layer with a thickness of 50 nm on the surface of a SnO2 film can improve the hydrogen gas sensitivity of a SnO2 film up to 112%, and reduce the response time to 80s.

Surface segregation and oxidation of Pt₃Ni(111) alloys under oxygen environment

Lee, H.C.,Kim, B.M.,Jeong, C.K.,Toyoshima, R.,Kondoh, H.,Shimada, T.,Mase, K.,Mao, B.,Liu, Z.,Lee, H.,Huang, C.Q.,Li, W.X.,Ross, P.N.,Mun, B.S. Elsevier Science Publishers 2016 CATALYSIS TODAY - Vol.260 No.-

<P>Utilizing ambient pressure X-ray photoelectron spectroscopy (AP-XPS), the surface segregation and oxidation of Pt3Ni(1 1 1) alloys are investigated as a function of temperature and oxygen pressure. The in situ AP-XPS measurements of oxygen oxidation process show that the Pt 'skin' surface is not stable under the exposure of oxygen pressure of 100 mTorr at room temperature. As the temperature and pressure are elevated, the formations of Ni2O3, NiOx, and NiO are observed on surface while Pt atom starts to reduce its adsorbed oxygen, which is a clear sign of surface segregation of Ni to surface. Upon the evacuation of oxygen gas, i.e. ultrahigh vacuum condition, both of NiOx and NiO oxide get reduced and Ni2O3 remains on the surface. The DFT calculation is employed to explain the formation of surface oxides under oxidation condition. (C) 2015 Elsevier B.V. All rights reserved.</P>

Effects of CSN1S2 Genotypes on Economic Traits in Chinese Dairy Goats

Yue, X.P.,Fang, Q.,Zhang, X.,Mao, C.C.,Lan, X.Y.,Chen, H.,Lei, Chuzhao Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.7

The aim of this study was to investigate allele frequencies at the CSN1S2 locus in two Chinese dairy goat breeds and the effects of its variation on dairy goat economic traits. Seven hundred and eight goats from Xinong Saanen (XS, n = 268) and Guanzhong (GZ, N = 440) breeds were selected. The milk samples of 268 XS goats were collected during the middle of lactation, body size parameters (708 goats) and daily milk yield (202 goats) were registered. The RFLP (restriction fragment length polymorphism) and SSCP (single strand conformation polymorphism) were used to detect the polymorphisms in CSN1S2. The Hardy-Weinberg (HW) equilibrium and the associations between body size, milk yield and composition and the genotypes were calculated. The results revealed that only A and F CSN1S2 alleles were found in the two Chinese dairy goat breeds. Allelic frequencies of A and F were 0.795, 0.205 and 0.739, 0.261 in Xinong Saanen and Guanzhong population respectively. Xinong Saanen breed was in Hardy-Weinberg equilibrium, while Guanzhong breed deviated from Hardy-Weinberg equilibrium (p<0.05). The association of polymorphism with economic traits indicated that the goats with FF genotype have higher milk fat and total solid concentration than those with AA and AF genotypes (p<0.05).

Development of AFLP Marker Linked to the Nematodes Resistance 'N' Gene in Pepper

L.H. Wang,X H. Gu,B X. Zhang,S L. Mao,D L. Peng,X F. Yun 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Development of the 3.7 GHz LHCD System on HL-2A

B. Lu,M. Huang,H. Zeng,X. Y. Bai,X. H. Mao,Z. H. Lu,J. Liang,Z. H. Kang,M. W. Wang,K. Feng,H. Wang,C. Wang,J. Q. Wang,S. Wei,T. Yao,Y. N. Bu,J. Feng,G. Y. Cheng,S. D. Song,D. H. Xia,J. Rao 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.8

A 2 MW-3.7 GHz lower hybrid current drive (LHCD) system is under development for physicsexperiments on the HL-2A device. The RF Power is generated by four TH2103A klystron amplifiersand propagates in the TE10 mode through WR284 waveguides. The transmission lines with a lengthof 20 m to 30 m are pressurized with 2 bars of nitrogen to decrease the possibility of arcing. Thelauncher, based on the passive-active multi-junction (PAM) concept, has been developed and iscurrently being realized. It was designed for a power spectrum peaked at Nk = 2.75 with goodcoupling properties over a wide range of plasma parameters. The four klystrons are fed by ahigh-voltage power supply (HVPS) based on the pulse step modulation (PSM) concept with a fastswitch-off time of less than ten μs. This system is expected to be in operation within 1 years and willexplore many international thermonuclear experimental reactor (ITER) related LH experiments inthe following years.

Development of Rice Pollen Strain Hr1004 and Test Fir its Wide Compatibility

D. Y Zhu,H. Pan,X. H. Shen,J. H. Yin,Y. Q. Jie,X. H. Ding,Y. Wan,L. H. Mao 한국육종학회 1997 한국육종학회 학술발표회 발표요지 Vol.29 No.2

Genetic Diversity of Wild Quail in China Ascertained with Microsatellite DNA Markers

Chang, G.B.,Chang, H.,Liu, X.P.,Zhao, W.M.,Ji, D.J.,Mao, Y.J.,Song, G.M.,Shi, X.K. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.12

The genetic diversity of domestic quail and two wild quail species, Japanese (Coturnix coturnix)and Common quail (Coturnix japonica), found in China was studied using microsatellite DNA markers. According to a comparison of the corresponding genetic indices in the three quail populations, such as Polymorphism Information Content (PIC), Mean Heterozygosity ($\bar{H}$) and Fixation Index, wild Common quail possessed rich genetic diversity with 4.67 alleles per site. Its values for PIC and $\bar{H}$ were the highest, 0.5732 and 0.6621, respectively. Domestic quail had the lowest values, 0.5467 and 0.5933, respectively. Wild Japanese quail had little difference in genetic diversity from domestic quail. In addition, from analyses of the fuzzy cluster based on standard genetic distance, the similarity relationship matrix coefficient between wild Japanese quail and domestic quail was 0.937, and that between wild Common quail and domestic quail was 0.783. All of these results showed that the wild Japanese quail were closer to the domestic quail for phylogenetic relationship than wild Common quail. These results at the molecular level provide useful data about quail's genetic background and further supported the hypothesis that the domestic quail originated from the wild Japanese quail.

Spectroscopic Ellipsometric Study of Size-Controlled Silicon Nano-Crystals in SiO2 Composite Thin Film

S.-Z. Feng,L.-Y. Chen,J. Li,P.-H. Mao,R.-J. Zhang,X.-F. Li,Y.-X. Zheng 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.II

In this work, a series of SiO$_x$/SiO$_2$ superlattices were prepared, by using reactive evaporation, with different thicknesses of the SiO$_x$ layers. After being annealed at 1100 $^\circ$C, composite thin films with the nano-crystals of silicon (nc-Si) embedded in the SiO$_2$ layers were formed. The optical properties of the films were measured by using the spectroscopic ellipsometric (SE) method in the photon energy range from 1.5 to 4.5 eV at three different incidence angles of 65$^\circ$, 70$^\circ$ and 75$^\circ$. In terms of the ellipsometric data, the effective medium approximation (EMA) with the four-parameter Lorentz oscillator model was used to fit the spectra and to extract the optical dispersion of the nc-Si particles. We found that the dielectric functions of the composite films strongly depended on the volume fraction of nc-Si and the constant of the SiO$_2$ layers, which changed with the composition in the investigated spectrum range

The Indosinian collision-extension event between the South China Block and the Palaeo-Pacific plate: Evidence from Indosinian alkaline granitic rocks in Dashuang, eastern Zhejiang, South China

Mao, J.,Ye, H.,Liu, K.,Li, Z.,Takahashi, Y.,Zhao, X.,Kee, W.S. Universitetsforlaget ; Elsevier Science Ltd 2013 Lithos Vol.172 No.-

This study reports on the first comprehensive analysis of the geology, petrology and origin of the Dashuang pluton in Jinhua, eastern Zhejiang, South China, which is predominantly composed of quartz monzonite and subordinate quartz syenite that includes variable amounts of aegirine-augite. The quartz monzonite has a porphyritic texture defined by K-feldspar phenocrysts, whereas the quartz syenite shows considerable variation in grain size and is categorised into fine- and coarse-grained types. Zircons from the quartz monzonite and fine-grained quartz syenite yield LA-MC-ICP-MS (laser ablation-multi-collector-inductively coupled plasma-mass spectrometry) U-Pb ages of 231.60+/-0.86Ma and 231.7+/-1.1Ma, respectively, indicating crystallisation in the Middle Triassic. The chemistry of the quartz monzonite indicates a calc-alkaline to alkaline evolutionary trend, which may reflect partial melting of upper mantle contaminated by Proterozoic basement rocks, subjected to fractional crystallisation during ascent. Both the fine- and coarse-grained quartz syenites are alkaline and have high rare earth element (REE) concentrations, especially light rare earth elements (LREE), and are relatively enriched in large ion lithosphere elements (LILE). The Al<SUB>2</SUB>O<SUB>3</SUB> and NaO<SUB>2</SUB> contents of the quartz syenite increase proportionally with SiO<SUB>2</SUB>, owing to greater amounts of aegirine-augite and feldspar. The fine-grained quartz syenite has the lowest initial <SUP>87</SUP>Sr/<SUP>86</SUP>Sr ratio and lowest Nd model age, and the highest ε<SUB>Nd</SUB> value compared with the quartz monzonite. The quartz syenite compositions are best explained by fractional crystallisation of an enriched mantle-derived alkaline magma. Slight chemical variations result from source heterogeneities, as well as the spatially variable degrees of melting, assimilation, and other factors. Our new age and geochemical data for the alkaline rocks in eastern Zhejiang, considered together with collisional granites from South Korea, support a history of collision and extension between the Palaeo-Pacific plate and the South China Block during the Indosinian. We use these data to refine the geodynamic model for Indosinian multi-plate convergence in South China.

Genetic Polymorphism of Milk Protein and Their Relationships with Milking Traits in Chinese Yak

Mao, Y.J.,Zhong, G.H.,Zheng, Y.C.,Pen, X.W.,Yang, Z.P.,Wang, Y.,Jiang, M.F. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.11

Milk protein polymorphisms were genotyped by polyacrylamide gel electrophoresis (PAGE) from 109 Maiwa and 100 Jiulong yaks. The relationships between milk protein polymorphisms and 3 milking traits were studied. The results showed that $\beta$-CN, $\kappa$-CN and $\alpha$-La were monomorphic, and ${\alpha}_{s1}$-CN and $\beta$-Lg were polymorphic, with ${\alpha}_{s1}$-CN D and $\beta$-Lg E as dominant genes, respectively. The frequencies of ${\alpha}_{s1}$-CN D were 0.8073 and 0.6000 in two populations and $\beta$-Lg E were 0.9770 and 0.9700. The mean heterozygosities were 0.1021 and 0.1867 in the two populations. No significant effects on milking traits and milk protein compositions were observed except for ${\alpha}_{s1}$-CN locus on fat percentage in Jiulong yak.