Fabrication of Nitrogen Doped p-ZnO and ZnO Light-Emitting Diodes on Sapphire

Y. M. Lu,Z. P. Wei,D. Z. Shen,Z. Z. Zhang,B. Yao,B. H. Li,J. Y. Zhang,D. X. Zhao,X. W. Fan,Z. K. Tang 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

Nitrogen-doped p-type ZnO thin films were grown on c-plane sapphire (Al2O3) substrates by plasma-assistant molecular beam epitaxy, where O2 and N2 were introduced via a RF plasma source simultaneously. In situ optical emission spectra of the plasma were employed to monitor the chemical species in the active gas sources, one of the most important growth parameters. By adjusting the growth parameters, we confirm the optimal condition for p-type doping growth. The reproducible p-type ZnO thin films have the hole concentration (NA −ND) up to 1.0 × 1018 cm−3 and the resistivity of 6 cm. A ZnO LED was fabricated by depositing undoped n-type ZnO on the p-type layer. Electroluminescence spectra centered about 430 nm were obtained even at 350 K.

A Cognition-inspired System for Data Stream Clustering

Zhaoyang Sun,K. Z. Mao,Wenyin Tang,Lee-Onn Mak,Kuitong Xian,Ying Liu 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.8

In applications such as target detection, domain knowledge of sensed data is often available. In this paper, we incorporate the available domain knowledge into clustering process and develop a knowledge-driven Mahalanobis distance-based ART (adaptive resonance theory) clustering algorithm. The strength of the knowledge-driven algorithm is that it can automatically determine the number of clusters with improved clustering results. The validity of the new algorithm has been verified on four artificial datasets. In addition, the algorithm has been adopted in our cognition-inspired system for clustering data stream, where known target library and dispersion of feature or attributes are available. The basic idea of this system is to divide data stream into frames, and to incorporate knowledge learned in previous frames into clustering of the following ones. Experimental studies have demonstrated that the evolving learning mechanism leads to improved clustering results compared with conventional incremental clustering algorithm Fuzzy ART and batch-based clustering algorithm k-means.

Fabrication of p-Type Nitrogen-Doped MgZnO by Depressing N-Related Donors

B. Yao,Z. P. Wei,Y. F. Li,D. Z. Shen,Y. M. Lu,Z. Z. Zhang,B. H. Li,C. J. Zheng,X. H. Wang,J. Y. Zhang,D. X. Zhao,X. W. Fan,Z. K. Tang 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

Wurtzite nitrogen-doped MgZnO (MgZnO:N) films were grown on c-plane sapphire by using plasma-assisted molecular beam epitaxy with radical NO as the oxygen source and nitrogen dopant. P-type conduction of MgZnO:N was obtained by decreasing the donor defects ((N2)O, VO, etc.) through annealing, revealing a hole concentration of 6.1 × 1017 cm−3 and a mobility of 6.42 cm2/Vs. Furthermore, as-grown p-type films with a hole concentration of 1 × 1017 cm−3 and a mobility of 3 cm2/Vs were obtained by decreasing the (N2)O double donor defect through control of the plasma conditions. ZnMgO:N/ZnO p-n junctions were obtained by using these p-type films. ode-like, rectifying I-V characteristics with a threshold voltage of about 5 V and a different reverse leakage current were observed at room temperature.

Tensile Yield Behaviour of Glass Bead Filled LDPE Composites

Liang, J . Z .,Tang, C . Y .,Li, R . K . Y .,Wong, T . T . 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.3

The effects of the filler size and the filler content on the tensile yield behaviour of glass bead filled low density polyethylene (LDPE) composites have been investigated employing an INSTRON materials tester at room temperature. The results show that the influence of the concentration and diameter of glass beads on the tensile yield stress and strain at yield state of the composites is insignificant. It indicates that the interfacial adhesion between the filler and the LDPE matrix is good.

Mechanical Properties of Polypropylene/CaCO3 Composites

Liang, J . Z .,Tang, C . Y .,Li, R . K . Y .,Wong, T . T . 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.4

The effects of calcium carbonate (CaCO₃) content on the hardness, tensile and dynamic mechanical properties and impact strength of the filled polypropylene (PP) composites have been investigated in the present paper. The results show that the moduli and hardness of the composites increase with addition of CaCO₃ content, but the tensile strength and strain at break is opposite to this; there are extreme values of the tensile yield stress and lzod impact strength at 5% and 10% of CaCO₃ weight fraction, respectively. It indicates that the strength and toughness of PP can be improved to some extent when PP i s filled with suitable concentration of inorganic rigid particles.

Numerical study of shock/vortex interaction in diatomic gas flows

Xiao, H.,Tang, K.,Xu, Z. Z.,Li, D. y.,Lyu, S. K. Springer Science + Business Media 2016 International Journal of Precision Engineering and Vol.17 No.1

<P>The particle-based direct simulation of Monte Carlo(DSMC) was present and validated for the investigation of non-equilibrium effects in diatomic gas flows. All the validations show that the results of the present DSMC is in agreement with the experimental data. Then, the numerical studies of micro scale shock/composite-vortex interactions in diatomic gas flows were conducted The substantial attenuation of enstrophy in diatomic gas flow is observed Differ from the sharp decreasing in diatomic gas, the time evolution of enstrophy in monatomic gas flow decrease linearly in the whole process. This study also shows that the vortex deformation through a shock, in particular, is observed to be strongly dependent on the shock and vortex strengths. Also, it is also found that strong interaction can also cause voracity production in microscale shock/vortex interaction for diatomic gas flow The attenuation, analogous to DSMC results, overwhelms the vorticity generation only in a limited set of regimes with low shock Mach number; small vortex size, or weak vortex. Besides, in diatomic gas flow, viscous voracity generation is also most dominant in the three dynamical processes of voracity transportation, followed by dilatational and baroclinicvorticity generation. The present study conform that shock/vortex present different features in strong and weak interactions for monatomic and diatomic gas flows. Furthermore, it provides a new way for the investigation of non-equilibrium effects.</P>

Mapping, Tissue Distribution and Polymorphism of Porcine Retinol Binding Protein Genes (RBP5 and RBP7)

Gong, W.H.,Tang, Z.L.,Han, J.L.,Yang, S.L.,Wang, H.,Li, Y.,Li, K. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.11

The retinoids (vitamin A and its derivatives) play a critical role in vision, growth, reproduction, cell differentiation and embryonic development. Using the IMpRH panel, porcine cellular retinol binding protein genes 5 and 7 (RBP5 and RBP7) were assigned to porcine chromosomes 5 and 6, respectively. The complete coding sequences (CDS) of the RBP5 and RBP7 genes were amplified using the reverse transcriptase polymerase chain reaction (RT-PCR) method, and the deduced amino acid sequences of both genes were compared to human corresponding proteins. The mRNA distributions of the two genes in adult Wuzhishan pig tissues (lung, skeletal muscle, spleen, heart, stomach, large intestine, lymph node, small intestine, liver, brain, kidney and fat) were examined. A total of nine single nucleotide polymorphisms (SNPs) were identified in two genes. Three of these SNPs were analyzed using the polymerase chain reaction-restriction-fragment length polymorphism (PCR-RFLP) method in Laiwu, Wuzhishan, Guizhou, Bama, Tongcheng, Yorkshire and Landrace pig breeds. Association analysis of genotypes of these SNP loci with economic traits was done in our experimental populations. Significant associations of different genotypes of $RBP5-A/G^{63}$, $RBP5-A/G^{517}$ and $RPB5-T/C^{intron1-90}$ loci with traits including maximum carcass length (LM), minimum carcass length (LN), marbling score (MS), back fat thickness at shoulder (SBF), meat color score (MCS) and hematocrit (HCT) were detected. These SNPs may be useful as genetic markers in genetic improvement for porcine production.

Polymorphism of Ghrelin Gene in Twelve Chinese Indigenous Chicken Breeds and Its Relationship with Chicken Growth Traits

C. C. Li,K. Li,J. Li,D. L. Mo,R. F. Xu,G. H. Chen,Y. Z. Qiangba,S. L. Ji,X. H. Tang,B. Fan,M. J. Zhu,T. A. Xiong,X. Guan,B. Liu 아세아·태평양축산학회 2006 Animal Bioscience Vol.19 No.2

A 2,656 bp fragment of chicken ghrelin gene was cloned and SNPs were detected by PCR-RFLP and Allele Specific PCR (ASP) in 12 Chinese indigenous chicken breeds and a commercial chicken population. The results showed that there were 23 base variations and an amino acid change (Gln->Arg) in cloned chicken ghrelin gene. Three SNPs were confirmed in 13 populations and associations between this gene and growth traits of Tibetan chicken (TC) and Recessive White chicken (RW) were investigated. The results of haplotype analysis revealed that 26 haplotype genotypes were composed of eight haplotypes. The results of x2 tests indicated that there were significant differences between genotypes or haplotype genotype frequencies in some of the breeds or sexes at 0.05 or 0.01 levels. The results of ANOVA revealed that there were significant differences between genotypes or haplotype genotypes on some growth traits of TC and RW chicken breeds at 0.05 or 0.01 levels. Multiple comparisons showed that there were significant associations between genotype CT at site 71 and some growth traits of two chicken breeds and between genotype AG at site 1,215 and body weight at 16 wk of two chicken breeds, and there was a significant association between haplotype genotype CAA/CAG and body weight and shank girth at 16 wk of two chicken breeds.

Environmentally friendly and non-polluting solvent pretreatment of palm samples for polyphenol analysis using choline chloride deep eutectic solvents

Fu, N.,Lv, R.,Guo, Z.,Guo, Y.,You, X.,Tang, B.,Han, D.,Yan, H.,Row, K.H. Elsevier 2017 Journal of chromatography Vol.1492 No.-

<P>In this work, choline chloride (ChCI) deep eutectic solvents (DESs) were evaluated for the pretreatment of palm samples in the analysis of polyphenols, such as protocatechuic acid, catechins, epicatechin, and caffeic acid. During the enrichment step of the pretreatment, eight DESs comprising ChCI with ethylene glycol (EG), glycerol (Gly), xylitol (Xyl), phenol (Ph), formic acid (FA), citric acid (CiA), oxalic acid (OA), or malonic acid (MA), were prepared and applied to the reflux extraction of polyphenols from palm samples. All the DESs exhibited higher polyphenol extraction efficiency than methanol, and the highest extraction efficiency was obtained using ChCI-FA (1:1, mole ratio). For the purification step of the pretreatment, eight ChCI DES-modified adsorbents were prepared by hydrothermal polymerization and packed into solid phase extraction (SPE) cartridges, and ChCI-Urea, ChCI-Gly, ChCI-FA, and water, were used as eluents. The ChCI DES-modified adsorbents were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, and Brunauer-Emmett-Teller surface analysis, and the polyphenols were analyzed by mass spectrometry and high-performance liquid chromatographultraviolet detection. The highest purification efficiency was obtained using the ChCI-Ph DES-modified adsorbent as the SPE packing material and ChCI-Urea-H2O (1:1:5, mole ratio), ChCI-Gly (1:1, mole ratio), ChCI-FA-H2O (1:1:5, mole ratio), and H2O as the eluents. Compared to conventional purification processes that employ commercial C-18 or C-8 SPE columns with organic solvents as eluents, the ChCI DES-based SPE purification process successfully avoided the use of expensive commercial SPE columns and organic solvents. Furthermore, it isolated a larger amount of the target compounds under the same experimental conditions, and could be applied over five cycles with good reversibility. This work indicates that DESs as green solvents have great potential for the totally green pretreatment of samples during the enrichment and purification processes. (C) 2017 Elsevier B.V. All rights reserved.</P>

A versatile platform for surface modification of microfluidic droplets

Li, M.,Jiang, W.,Chen, Z.,Suryaprakash, S.,Lv, S.,Tang, Z.,Chen, X.,Leong, K. Royal Society of Chemistry 2017 Lab on a chip Vol.17 No.4