Enhanced strength and ductility in particulate-reinforced aluminum matrix composites fabricated by flake powder metallurgy

Kai, X.Z.,Li, Z.Q.,Fan, G.L.,Guo, Q.,Xiong, D.B.,Zhang, W.L.,Su, Y.S.,Lu, W.J.,Moon, W.J.,Zhang, D. Elsevier Sequoia 2013 Materials science & engineering. properties, micro Vol.587 No.-

Reinforcement agglomeration always leads to severe stress concentration and porosity, which is detrimental to the deformation ability and mechanical properties of particulate-reinforced metal matrix composites. In this study, uniform distribution of 32vol%B<SUB>4</SUB>C has been achieved in B<SUB>4</SUB>C/Al composite by means of flake powder metallurgy (Flake PM), in which flake Al powder is used as the starting material. The flake Al powder exhibits higher apparent volume than spherical powders of the same mass, and thus can provide more space to accommodate the B<SUB>4</SUB>C particles. Therefore, compared with conventional PM, Flake PM can lead to more uniform distribution of B<SUB>4</SUB>C particles in the composite powder as well as in the consolidated composite. Meanwhile, the flake Al powder has a nano skin of Al<SUB>2</SUB>O<SUB>3</SUB>, which could be fractured and dispersed inside the fine matrix grains during consolidation, and were found to induce a higher normalized strain hardening rate for the composite during deformation. As a result, the Flake PM 32vol%B<SUB>4</SUB>C/Al composite exhibits an ultimate tensile strength of 305MPa and a uniform elongation of 6.6%, 63% stronger and 13% more ductile than its counterpart fabricated by conventional PM.

Investigation of PCR-RFLPs within Major Histocompatibility Complex B-G Genes Using Two Restriction Enzymes in Eight Breeds of Chinese Indigenous Chickens

R. F. Xu,K. Li,G. H. Chen,B. Y. Z. Qiang,D. L. Mo,B. Fan,C. C. Li,M. Yu,M. J. Zhu,T. A. Xiong,B. Liu 아세아·태평양축산학회 2005 Animal Bioscience Vol.18 No.7

New polymorphism of major histocompatibility complex B-G genes was investigated by amplification and digestion of a 401bp fragment including intron 1 and exon 2 using polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) technique with two restriction enzymes of Msp I and Tas I in eight breeds of Chinese indigenous chickens and one exotic breed. In the fragment region of the gene, three novel single nucleotide polymorphisms (SNPs) were detected at the two restriction sites. We found the transition of two nucleotides of A294G and T295C occurred at Tas I restriction site, and consequently led to a nonsynonymous substitution of asparagine into serine at position 54 within the deduced amino acid sequence of immunoglobulin variableregion- like domain encoded by the exon 2 of B-G gene. It was observed at rare frequency that a single mutation of A294G occurring at the site, also caused an identical substitution of amino acid, asparagine 54-to-serine, to that we described previously. And the transversion of G319C at Msp I site led to a non-synonymous substitution, glutamine 62-to-histidine. The new alleles and allele frequencies identified by the PCR-RFLP method with the two enzymes were characterized, of which the allele A and B frequencies at Msp I and Tas I loci were given disequilibrium distribution either in the eight Chinese local breeds or in the exotic breed. By comparison, allele A at Msp I locus tended to be dominant, while, the allele B at Tas I locus tended to be dominant in all of the breeds analyzed. In Tibetan chickens, the preliminary association analysis revealed that no significant difference was observed between the different genotypes identified at the Msp I and Tas I loci and the laying performance traits, respectively.

Individual-breed Assignment Analysis in Swine Populations by Using Microsatellite Markers

Fan, B.,Chen, Y.Z.,Moran, C.,Zhao, S.H,Liu, B.,Yu, M.,Zhu, M.J.,Xiong, T.A.,Li, K. Asian Australasian Association of Animal Productio 2005 Animal Bioscience Vol.18 No.11

Individual-breed assignments were implemented in six swine populations using twenty six microsatellites recommended by the Food and Agriculture Organization and the International Society for Animal Genetics (FAO-ISAG). Most microsatellites exhibited high polymorphisms as shown by the number of alleles and the polymorphism information content. The assignment accuracy per locus obtained by using the Bayesian method ranged from 33.33% (CGA) to 68.47% (S0068), and the accumulated assignment accuracy of the top ten loci combination added up to 96.40%. The assignment power of microsatellites based on the Bayesian method had positive correlations with the number of alleles and the gene differential coefficient ($G_{st}$) per locus, while it has no relationship to genetic heterozygosity, polymorphism information content per locus and the exclusion probabilities under case II and case III. The percentage of corrected assignment was highest for the Bayesian method, followed by the gene frequency and distancebased methods. The assignment efficiency of microsatellites rose with increase in the number of loci used, and it can reach 98% when using a ten-locus combination. This indicated that such a set of ten microsatellites is sufficient for breed verification purposes.

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.

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.

Effect of Genotype on Whole-body and Intestinal Metabolic Response to Monensin in Mice

Fan, Y.K.,Croom, W.J.,Daniel, Linda,McBride, B.W.,Koci, M.,Havenstein, G.B.,Eisen, E.J. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.4

Two lines of mice, M16 selected for rapid growth and a randomly selected control ICR as well as their reciprocal crosses were used to study the effects of genotype on whole-body energetics and intestinal responses to monensin. Six mice, eight weeks of age, from each line or reciprocal cross were assigned to one of two treatments, 1) drinking water containing 20 mmol/L monensin dissolved in 0.5% V/V ethanol, and 2) drinking water containing 0.5% V/V ethanol (control) for two weeks. After 11 days (age of 9 weeks and 4 days), whole-body $O_2$ consumption was measured. At the end of two weeks, jejunal $O_2$ consumption, intestinal tissue composition and histomorphometrics as well as the rate and efficiency of glucose absorption were estimated. In comparison with the control, monensin administration in drinking water resulted in less daily water intake (13.4 vs. 15.5 ml/mouse, p<0.01), less protein to DNA ratio of jejunal mucosa (5.41 vs. 6.01 mg/mg, p<0.05), lower villus width (88 vs. $100{\mu}m$, p<0.05), and less jejunal tissue $O_2$ consumption enhancement by alcohol (7.2 vs. 10.5%, p<0.01) in mice. Other than those changes, monensin had little (p>0.05) effect on variables measured in either line of mice or their reciprocal cross. In contrast, the M16 line, selected for rapid growth, as compared to the ICR controls or the reciprocal crosses, had less initial (pre-monensin treatment) whole-body $O_2$ consumption per gram of body weight (1.68 vs. $2.11-2.34{\mu}mol/min{\cdot}g$ BW, p<0.01) as compared to the ICR and reciprocal crosses. In addition, the M16 mice exhibited greater growth (412 vs. 137-210 mg/d, p<0.05), better feed efficiency (41.7 vs. 19.9-29.3 mg gain/g feed, p<0.05), shorter small intestines adjusted for fasted body weight (1.00 vs. 1.22-1.44 cm/g FBW, p<0.05), wider villi (109 vs. $87-93{\mu}m$, p<0.05), more mature height of enterocytes (28.8 vs. $24.4-25.1{\mu}m$, p<0.05) and a lower rate (91 vs. $133-145{\eta}mol\;glucose/min{\cdot}g$ jejunum, p<0.05) and less energetic efficiency (95 vs. $59-72{\eta}mol$ ATP expended/${\eta}mol$ glucose uptake, p<0.05) of glucose absorption compared to the ICR line and the reciprocal cross. Monensin had little (p>0.05) effect on whole-body $O_2$ consumption and jejunal function, whilst selection for rapid growth resulted in an apparent down-regulation of intestinal function. These data suggest that genetic selection for increased growth does not result in concomitant changes in intestinal function. This asynchrony in the selection for production traits and intestinal function may hinder full phenotypic expression of genotypic growth potential.

Effect of channel thickness on electrical performance of amorphous IGZO thin-film transistor with atomic layer deposited alumina oxide dielectric

Y. Li,Y.L. Pei,R.Q. Hu,Z.M. Chen,Y. Zhao,Z. Shen,B.F. Fan,J. Liang,G.Wang 한국물리학회 2014 Current Applied Physics Vol.14 No.7

We have investigated the electrical performance of amorphous indiumegalliumezinc oxide (a-IGZO) thin-film transistors with various channel thicknesses. It is observed that when the a-IGZO thickness increases, the threshold voltage decreases as reported at other researches. The intrinsic field-effect mobility as high as 11.1 cm2/Vs and sub threshold slope as low as w0.2 V/decade are independent on the thickness of a-IGZO channel, which indicate the excellent interface between a-IGZO and atomic layer deposited Al2O3 dielectric even for the case with a-IGZO thickness as thin as 10 nm. However, the source and drain series resistances increased with increasing of a-IGZO channel thickness, which results in the apparent field-effect mobility decreasing. The threshold voltage shift (DVth) under negative bias stress (NBS) and negative bias illumination stress (NBIS) were investigated, also. The hump-effect in the sub threshold region under NBS and threshold voltage shift to negative position under NBIS were enhanced with decreasing of a-IGZO channel thickness, owing to the enhancement of vertical electrical field in channel.

Effect of interfacial wavy motion on film boiling heat transfer from isothermal downward-facing hemispheres

Kim, Chan Soo,Suh, Kune Y.,Rempe, Joy L.,Cheung, Fan B.,Kim, Sang B. Elsevier 2005 Nuclear engineering and design Vol.235 No.20

<P><B>Abstract</B></P><P>Film boiling heat transfer coefficients for a downward-facing hemispherical surface are measured from the quenching tests in Downward-Boiling Experiment Laminar Transition Apparatus (DELTA). Two test sections are made of copper to maintain low Biot numbers. The outer diameters of the hemispheres are 120 and 294mm, respectively. The thickness of all the test sections is 30mm. The effect of diameter on film boiling heat transfer is quantified utilizing results obtained from the test sections. The measured data are compared with the numerical predictions from laminar film boiling analysis. The measured heat transfer coefficients are found to be greater than those predicted by the conventional laminar flow theory on account of the interfacial wavy motion incurred by the Helmholtz instability. Incorporation of the wavy motion model considerably improves the agreement between the experimental and numerical results in terms of heat transfer coefficient. In addition, the film boiling was visualized using a digital camera.</P>

Effects of exogenous phytase and xylanase, individually or in combination, and pelleting on nutrient digestibility, available energy content of wheat and performance of growing pigs fed wheat-based diets

Yang, Y.Y.,Fan, Y.F.,Cao, Y.H.,Guo, P.P.,Dong, B.,Ma, Y. X. Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.1

Objective: Two experiments were conducted to determine the effects of adding exogenous phytase and xylanase, individually or in combination, as well as pelleting on nutrient digestibility, available energy content of wheat and the performance of growing pigs fed wheat-based diets. Methods: In Experiment 1, forty-eight barrows with an initial body weight of $35.9{\pm}0.6kg$ were randomly assigned to a $2{\times}4$ factorial experiment with the main effects being feed form (pellet vs meal) and enzyme supplementation (none, 10,000 U/kg phytase, 4,000 U/kg xylanase or 10,000 U/kg phytase plus 4,000 U/kg xylanase). The basal diet contained 97.8% wheat. Pigs were placed in metabolic cages for a 7-d adaptation period followed by a 5-d total collection of feces and urine. Nutrient digestibility and available energy content were determined. Experiment 2 was conducted to evaluate the effects of pelleting and enzymes on performance of wheat for growing pigs. In this experiment, 180 growing pigs ($35.2{\pm}9.0kg\;BW$) were allocated to 1 of 6 treatments according to a $2{\times}3$ factorial treatment arrangement with the main effects being feed form (meal vs pellet) and enzyme supplementation (0, 2,500 or 5,000 U/kg xylanase). Results: In Experiment 1, there were no interactions between feed form and enzyme supplementation. Pelleting reduced the digestibility of acid detergent fiber (ADF) by 6.4 percentage units (p<0.01), increased the digestibility of energy by 0.6 percentage units (p<0.05), and tended to improve the digestibility of crude protein by 0.5 percentage units (p = 0.07) compared with diets in mash form. The addition of phytase improved the digestibility of phosphorus (p<0.01) and calcium (p<0.01) by 6.9 and 7.6 percentage units respectively compared with control group. Adding xylanase tended to increase the digestibility of crude protein by 1.0 percentage units (p = 0.09) and increased the digestibility of neutral detergent fiber (NDF) (p<0.01) compared with control group. Supplementation of the xylanase-phytase combination improved the digestibility of phosphorus (p<0.01) but impaired NDF digestibility (p<0.05) compared with adding xylanase alone. In Experiment 2, adding xylanase increased average daily gain (p<0.01) and linearly improved the feed:gain ratio (p<0.01) compared with control group. Conclusion: Pelleting improved energy digestibility but decreased ADF digestibility. Adding xylanase increased crude protein digestibility and pig performance. Phytase increased the apparent total tract digestibility of phosphorus and calcium. The combination of phytase-xylanase supplementation impaired the effects of xylanase on NDF digestibility.

Coronary Atherosclerosis T₁-Weighed Characterization With Integrated Anatomical Reference

Xie, Y.,Kim, Y.J.,Pang, J.,Kim, J.S.,Yang, Q.,Wei, J.,Nguyen, C.T.,Deng, Z.,Choi, B.W.,Fan, Z.,Bairey Merz, C.N.,Shah, P.K.,Berman, D.S.,Chang, H.J.,Li, D. Elsevier Science B.V. Amsterdam 2017 JACC CARDIOVASCULAR IMAGING Vol.10 No.6

Objectives: The aim of this work is the development of coronary atherosclerosis T<SUB>1</SUB>-weighted characterization with integrated anatomical reference (CATCH) technique and the validation by comparison with high-risk plaque features (HRPF) observed on intracoronary optical coherence tomography (OCT) and invasive coronary angiography. Background: T<SUB>1</SUB>-weighted cardiac magnetic resonance with or without contrast media has been used for characterizing coronary atherosclerosis showing promising prognostic value. Several limitations include: 1) coverage is limited to proximal coronary segments; 2) spatial resolution is low and often anisotropic; and 3) a separate magnetic resonance angiography acquisition is needed to localize lesions. Methods: CATCH acquired dark-blood T<SUB>1</SUB>-weighted images and bright-blood anatomical reference images in an interleaved fashion. Retrospective motion correction with 100% respiratory gating efficiency was achieved. Reference control subjects (n = 13) completed both pre- and post-contrast scans. Stable angina patients (n = 30) completed pre-contrast scans, among whom 26 eligible patients also completed post-contrast scans. After cardiac magnetic resonance, eligible patients (n = 22) underwent invasive coronary angiography and OCT for the interrogation of coronary atherosclerosis. OCT images were assessed and scored for HRPF (lipid-richness, macrophages, cholesterol crystals, and microvessels) by 2 experienced analysts blinded to magnetic resonance results. Results: Per-subject analysis showed none of the 13 reference control subjects had coronary hyperintensive plaques (CHIP) in either pre-contrast or post-contrast CATCH. Five patients had CHIP on pre-contrast CATCH and 5 patients had CHIP on post-contrast CATCH. Patients with CHIP had greater lipid abnormality than those without. Per-segment analysis showed elevated pre- and post-contrast plaque to myocardium signal ratio in the lesions with HRPF versus those without. Positive correlation was observed between plaque to myocardium signal ratio and OCT HRPF scoring. CHIP on pre-contrast CATCH were associated with significantly higher stenosis level than non-CHIP on invasive coronary angiography. Conclusions: CATCH provided accelerated whole heart coronary plaque characterization with simultaneously acquired anatomical reference. CHIP detected by CATCH showed positive association with high-risk plaque features on invasive imaging studies.