Influence of Microstructure Evolution on Mechanical Properties, Wear Resistance and Corrosion Resistance of Ti(C,N)-Based Cermet Tools with Various WC Additions

L. B. Zhao,N. Lin,X. Q. Han,C. Ma,Z. Y. Wang,Y. H. He 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.8

The efects of tungsten carbide addition on the microstructure, mechanical properties and corrosion resistance of Ti(C,N)-based cermets prepared by the sinter-HIP method are investigated through scanning electron microscope, X-ray difraction,electron back scattered difraction, mechanical test and electrochemical method. The results show that the appropriate WCaddition has an important infuence on promoting the formation of core-rim microstructure of cermet, increasing the wettability of ceramic phase and binder phase, and improving the mechanical properties. Ti(C,N)-based cermet with 5 wt% WCaddition has the highest hardness of 92.4 HRA and excellent wear resistance. However, excessive WC addition causes theappearance of slight white core phase containing plenty of W and Ti element in microstructure, which increases the fracturetoughness, and reduces the hardness and wear resistance of cermet. Additionally, the electrochemical result shows that theaddition of 5 wt% WC in cermet has the optimal corrosion resistance in 1 mol/L hydrochloric acid solution.

Measurement of the Secondary Neutron Emission Differential and Double-Differential Cross Sections between 20 and 30 MeV

X. C. Ruan,G. C. Chen,H. X. Huang,X. Li,Y. B. Nie,B. Zhou,Z. Y. Ma,J. Bao,Q. P. Zhong,Z. Y. Zhou,H. Q. Tang,J. S. Zhang,C. L. Lan,Y. L. Zhang,Y. M. Li 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23

More and more interests have been paid to the differential and double-differential neutron emission cross sections (DX and DDX) at above 20 MeV region in recent years. At the China Institute of Atomic Energy (CIAE), a program to measure the DX and DDX between 20 and 30 MeV neutron energy region has been carried out. The d-T reaction neutron source was used to produce the 20 - 30 MeV neutrons with a tritium gas target at the HI-13 tandem accelerator at CIAE. The time-of-flight(TOF) technique was used to measure the neutron energy from about 1 MeV to 30 MeV with 3 BC501A liquid scintillators (with a size of Φ180 ×100 mm). A preliminary measurement has been carried out for ^9Be at 22 MeV. The measured data were analyzed by detailed Monte-Carlo simulation to perform the multiple scattering, flux attenuation and finite geometry corrections. The experimental details, the data analysis, the progress, the results and the future plan will be presented in this report.

Evolution of surface O₃ and PM_2.5 concentrations and their relationships with meteorological conditions over the last decade in Beijing

Zhang, Z.,Zhang, X.,Gong, D.,Quan, W.,Zhao, X.,Ma, Z.,Kim, S.J. Pergamon Press ; Elsevier [distribution] 2015 Atmospheric environment Vol.108 No.-

In this study, hourly and daily records since 2005 and correlation, regression and composite methods were used to analyze the long-term evolution of surface O<SUB>3</SUB> and PM<SUB>2.5</SUB> concentrations at the rural station of Shangdianzi (SDZ) and urban station of Baolian (BL) over Beijing and their relationships with meteorological conditions. The results show that the mean concentrations of PM<SUB>2.5</SUB> (O<SUB>3</SUB>) decreased (increased) at the urban and rural stations over the last decade. The linear trends of the annual mean concentrations of PM<SUB>2.5</SUB> at BL and SDZ were -31.8 ug/m<SUP>3</SUP>/10yr (-4.3%/yr) (p < 0.01) and -13.3 ug/m<SUP>3</SUP>/10yr (-2.9%/yr) (p < 0.05), respectively. In winter, the mean wind speed (W<SUB>s</SUB>) and relative humidity (RH) were the most closely correlated with O<SUB>3</SUB> at both stations, whereas RH and sunshine hours (S) were most closely correlated with PM<SUB>2.5</SUB>. The correlation coefficients and explained variances in spring and autumn were generally less than those in winter and greater than those in summer. Moreover, increase in precipitation can significantly reduce the PM<SUB>2.5</SUB> concentration in both urban and rural areas in Beijing, whereas trace and light precipitation more effectively decreases the O<SUB>3</SUB> concentration. Concentrations of PM<SUB>2.5</SUB> (O<SUB>3</SUB>) on haze days increased by 114% (3%) and 162% (20%) compared with that on non-haze days at the urban and rural stations, respectively. This result suggests that haze is a major manifestation of air pollution in Beijing.

PHYSICAL-CHEMICAL PROPERTIES OF ETHANOL-DIESEL BLEND FUEL AND ITS EFFECT ON THE PERFORMANCE AND EMISSIONS OF A TURBOCHARGED DIESEL ENGINE

Z.-Q. CHEN,X.-X. MA,S.-T. YU,Y.-N. GUO,J.-S. LIU 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.3

This paper deals with the main physical-chemical properties of ethanol-diesel blend and the effects of ethanoldiesel blends (up to 15% volume) on engine performance (full load torque vs. engine speed, BSEC vs. torque at 1400 r/min and 2300 r/min, and effect of start of injection angle) and emissions in ECE R49 tests (steady 13 points) using a 6.6 L inline 6-cylinder turbocharged direct injection diesel engine. The results show that an increase in ethanol fraction results in decreased viscosity of the blend fuel and very high distillation characteristics in the low temperature range. Solvents can improve the solubility of ethanol-diesel blends. The engine power was degraded proportional to the ethanol content (10% and 15%) due to the LHV (low heating value) of the blends. The higher latent heat of vaporization and lower CN (cetane number) of ethanol, which results from the steady state emissions of CO, HC, and SOF (soluble organic fraction), were much higher in the ECE R49 tests at low loads. Soot (solid mass) emissions were improved. The particulate matter emissions were significantly increased with higher blend volumes, and NOx emissions slightly increased with higher ethanol volumes. By increasing the injection angle properly, the performance parameters of the diesel engine were improved, but NOx emissions were deteriorated slightly. This paper deals with the main physical-chemical properties of ethanol-diesel blend and the effects of ethanoldiesel blends (up to 15% volume) on engine performance (full load torque vs. engine speed, BSEC vs. torque at 1400 r/min and 2300 r/min, and effect of start of injection angle) and emissions in ECE R49 tests (steady 13 points) using a 6.6 L inline 6-cylinder turbocharged direct injection diesel engine. The results show that an increase in ethanol fraction results in decreased viscosity of the blend fuel and very high distillation characteristics in the low temperature range. Solvents can improve the solubility of ethanol-diesel blends. The engine power was degraded proportional to the ethanol content (10% and 15%) due to the LHV (low heating value) of the blends. The higher latent heat of vaporization and lower CN (cetane number) of ethanol, which results from the steady state emissions of CO, HC, and SOF (soluble organic fraction), were much higher in the ECE R49 tests at low loads. Soot (solid mass) emissions were improved. The particulate matter emissions were significantly increased with higher blend volumes, and NOx emissions slightly increased with higher ethanol volumes. By increasing the injection angle properly, the performance parameters of the diesel engine were improved, but NOx emissions were deteriorated slightly.

Ablation of irradiated metals by high-intensity pulsed ion beam

X. P. Zhu,M. K. Lei,S. M. Miao,T. C. Ma,Z. H. Dong 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.III

Surface morphology and roughness of pure Ti irradiated by high-intensity pulsed ion beam (HIPIB) have been investigated by using scanning electronic microscope (SEM) and profilometer, respectively. The HIPIB irradiation was carried out at an accelerating voltage of 220 kV, an ion current density of \symbol{126}250 A/cm$^2$ with 75 ns pulse width under single or multi shots. Craters were formed on the irradiated surfaces and their dimension was expanded with increasing the ion current density. At $<$90 A/cm$% ^2 $, small craters of $\mu $m size were observed on the weakly melted surface. At 90-120 A/cm$^2$, large craters about 10 $\mu $m were found on the obviously melted surface. At 120-250 A/cm$^2$, the surface was severely melted with craters and the size of the craters increased to 20-80 $\mu $m with a wavy feature. At 250 A/cm$^2$ with 1 shot, surface roughness (\textit{% R}$_{\mathit{a}}$) greatly increased to a maximal value of 0.43 $\mu $m from the initial \textit{R}$_{\mathit{a}}$ of 0.18 $\mu $m, in good agreement with the SEM observation. With further increasing the shot number, the \textit{R}$_{\mathit{a}}$ decreased continuously and finally reached 0.06 $% \mu $m with 30 shots, indicating a planar ablated surface. The micro non-uniformity on the surfaces induced a selective ablation under HIPIB irradiation. The locally liquid evaporation and droplet ejection led to a disturbance in the molten surface layer to different scales depending on the ion current densities. On the other hand, the micro non-uniformity disappeared gradually under multi-shot irradiation, resulting in a more uniform ablation due to the diminished selective ablation.

Three-dimensional mapping of the anisotropic magnetoresistance in Fe₃O₄ single crystal thin films

Ding, Z.,Li, J. X.,Zhu, J.,Ma, T. P.,Won, C.,Wu, Y. Z. American Institute of Physics 2013 JOURNAL OF APPLIED PHYSICS - Vol.113 No.17

<P>The anisotropic magnetoresistance (AMR) effect with a magnetic field along arbitrary directions in single crystalline (001)-oriented Fe3O4 films was studied. A cubic symmetry term, an in-plane uniaxial term, and an out-of-plane uniaxial term could be quantitatively separated. The cubic term is independent of the current direction, and decreases with increasing temperature, but both in-plane and out-of-plane uniaxial terms are found to be strongly dependent on the current orientation. This three-dimensional magnetoresistance measurement provides a quantitative method for identifying the different contributions to the AMR effect. (C) 2013 American Institute of Physics.</P>

Effect of Genistein on Antioxidative Defence System and Membrane Fluidity in Chick Skeletal Muscle Cells

Jiang, Z.Y.,Jiang, S.Q.,Lin, Y.C.,Ma, X.Y.,Xi, P.B.,Cao, T.,Wang, X.Q. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.8

This study was conducted to investigate the protective effect of genistein on the antioxidative defence system and membrane fluidity in chick skeletal muscle cells after supplementation with 0, 20, 40, and $80{\mu}mol/L$ genistein in $50{\mu}mol/L$ $FeSO_4/H_2O_2$ treated cells for 24 h. Genistein supplementation recovered the decreased activity of total superoxide dismutase induced by $FeSO_4/H_2O_2$, significantly increased glutathione peroxidase activity (p<0.05) and decreased malondialdehyde production (p<0.05). The treatment of 80 mol/L genistein in $FeSO_4/H_2O_2$ treated cells decreased the secretion of creatine kinase (p<0.05). Fluorescence polarization values and microviscosities observed with $FeSO_4/H_2O_2$ treated cells were significantly higher than those observed with no $FeSO_4/H_2O_2$ treated cells. The addition of $80{\mu}mol/L$ genistein improved the increased fluorescence polarization value (p<0.05) caused by $FeSO_4/H_2O_2$ treatment. The microviscosity value was significantly decreased by adding genistein (p<0.05). In conclusion, genistein protected skeletal muscle cells from oxidative damage by improving antioxidative status and membrane fluidity.

Tissue Distribution, SNP Detection and Association Study with Immune Traits of Porcine LBP and CD14 Genes

Liu, H.Z.,Li, X.Y.,Liu, B.,Yu, M.,Ma, Y.H.,Chu, M.X.,Li, K. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.8

Lipopolysaccharide binding protein (LBP) and CD14 protein play important roles in the defense against infection of Gram-negative bacteria. In the present study, tissue distribution and polymorphism of porcine LBP and CD14 genes were analyzed. Real-time PCR results showed that the porcine LBP gene was especially highly expressed in liver, while CD14 gene was highly expressed in liver and spleen tissues. A 1,732 bp cDNA fragment of porcine LBP gene and a 1,682 bp genomic DNA fragment of CD14 gene were isolated. Polymorphisms were identified in these two fragments and showed that there were 14 potential SNPs in the porcine LBP gene and 3 potential SNPs in the porcine CD14 gene. Three SNPs, 292G/A (Gly/Ser), 1168G/A (Ala/Thr) of the LBP gene and -61G/A of the CD14 gene, were genotyped using restriction fragment length polymorphism (RFLP) method. Association analyses indicated that polymorphism of the 292G/A locus was significantly associated with porcine immune traits hematocrit (HCT), IgG and delayed-type hypersensitivity (DTH) (p<0.01), and the 1168G/A locus was significantly associated with HCT and mean corpuscular volume (MCV) traits (p<0.05). No significant association was found between the -61G/A locus and immune traits of the pig. Our data indicated that the LBP gene was significantly associated with immune traits of pig. Also, we identified some SNPs which may be useful markers for disease-resistant breeding of pigs.

Effect of Na2O on the Reduction of Fe2O3 Compacts with CO/CO2

Pan, W.,Ma, Z. J.,Zhao, Z. X.,Kim, W. H.,Min, D. J. Springer Verlag 2012 Metallurgical and materials transactions. B, Proce Vol.43 No.6

Genetic Differentiation of Chinese Indigenous Meat Goats Ascertained Using Microsatellite Information

Ling, Y.H.,Zhang, X.D.,Yao, N.,Ding, J.P.,Chen, H.Q.,Zhang, Z.J.,Zhang, Y.H.,Ren, C.H.,Ma, Y.H.,Zhang, X.R. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.2

To investigate the genetic diversity of seven Chinese indigenous meat goat breeds (Tibet goat, Guizhou white goat, Shannan white goat, Yichang white goat, Matou goat, Changjiangsanjiaozhou white goat and Anhui white goat), explain their genetic relationship and assess their integrity and degree of admixture, 302 individuals from these breeds and 42 Boer goats introduced from Africa as reference samples were genotyped for 11 microsatellite markers. Results indicated that the genetic diversity of Chinese indigenous meat goats was rich. The mean heterozygosity and the mean allelic richness (AR) for the 8 goat breeds varied from 0.697 to 0.738 and 6.21 to 7.35, respectively. Structure analysis showed that Tibet goat breed was genetically distinct and was the first to separate and the other Chinese goats were then divided into two sub-clusters: Shannan white goat and Yichang white goat in one cluster; and Guizhou white goat, Matou goat, Changjiangsanjiaozhou white goat and Anhui white goat in the other cluster. This grouping pattern was further supported by clustering analysis and Principal component analysis. These results may provide a scientific basis for the characteristization, conservation and utilization of Chinese meat goats.