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Your search keyword '"Zheng, Y.J."' showing total 43 results
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43 results on '"Zheng, Y.J."'

17. RFI test observations at a candidate SKA site in China

Author

Peng, B., Sun, J.M., Zhang, H.Y., Piao, T.Y., Li, J.Q., Lei, L., Luo, T., Li, D.H., Zheng, Y.J., and Nan, R.

Subjects
Astronomy -- Observations, Radio telescopes -- Planning, Radio telescopes -- Design and construction, Radio telescopes -- Location, Company business planning, Science and technology
Published
2004

24. Highway increases concentrations of toxic metals in giant panda habitat

Author

Zheng, Y.J., Chen, Y.P., Maltby, L., and Jin, X.L.

Abstract

The Qinling panda subspecies (Ailuropoda melanoleuca qinlingensis) is highly endangered with fewer than 350 individuals inhabiting the Qinling Mountains. Previous studies have indicated that giant pandas are exposed to heavy metals, and a possible source is vehicle emission. The concentrations of Cu, Zn, Mn, Pb, Cr, Ni, Cd, Hg, and As in soil samples collected from sites along a major highway bisecting the panda's habitat were analyzed to investigate whether the highway was an important source of metal contamination. There were 11 sites along a 30-km stretch of the 108th National Highway, and at each site, soil samples were taken at four distances from the highway (0, 50, 100, and 300 m) and at three soil depths (0, 5, 10 cm). Concentrations of all metals except As exceeded background levels, and concentrations of Cu, Zn, Mn, Pb, and Cd decreased significantly with increasing distance from the highway. Geo-accumulation index indicated that topsoil next to the highway was moderately contaminated with Pb and Zn, whereas topsoil up to 300 m away from the highway was extremely contaminated with Cd. The potential ecological risk index demonstrated that this area was in a high degree of ecological hazards, which were also due to serious Cd contamination. And, the hazard quotient indicated that Cd, Pb, and Mn especially Cd could pose the health risk to giant pandas. Multivariate analyses demonstrated that the highway was the main source of Cd, Pb, and Zn and also put some influence on Mn. The study has confirmed that traffic does contaminate roadside soils and poses a potential threat to the health of pandas. This should not be ignored when the conservation and management of pandas is considered.

Published
2016

26. Aplastic anaemia associated with parvovirus B19 infection. (Short Report)

Author

Qian, X.H., Zhang, G.C., Jiao, X.Y., Zheng, Y.J., Cao, Y.H., Xu, D.L., and Chen, C.S.

Subjects
Children -- Diseases, Aplastic anemia -- Physiological aspects -- Research, Parvovirus infections -- Causes of -- Research -- Physiological aspects, Family and marriage, Health, Physiological aspects, Research, Causes of
Abstract

Parvovirus B19 involvement was investigated in 30 children with severe aplastic anaemia. Active or recent porvovirus B19 infection, as shown by B19 DNA viraemia, positive B19 specific IgM antibodies, or [...]

Published
2002

38. Recent advances in the HL-2A tokamak experiments

Author

Liu, Y, primary, Ding, X.T, additional, Yang, Q.W, additional, Yan, L.W, additional, Liu, D.Q, additional, Xuan, W.M, additional, Chen, L.Y, additional, Song, X.M, additional, Cao, Z, additional, Zhang, J.H, additional, Mao, W.C, additional, Zhou, C.P, additional, Li, X.D, additional, Wang, S.J, additional, Yan, J.C, additional, Bu, M.N, additional, Chen, Y.H, additional, Cui, C.H, additional, Cui, Z.Y, additional, Deng, Z.C, additional, Hong, W.Y, additional, Hu, H.T, additional, Huang, Y, additional, Kang, Z.H, additional, Li, B, additional, Li, W, additional, Li, F.Z, additional, Li, G.S, additional, Li, H.J, additional, Li, Q, additional, Li, Y.G, additional, Li, Z.J, additional, Liu, Yi, additional, Liu, Z.T, additional, Luo, C.W, additional, Mao, X.H, additional, Pan, Y.D, additional, Rao, J, additional, Shao, K, additional, Song, X.Y, additional, Wang, M, additional, Wang, M.X, additional, Wang, Q.M, additional, Xiao, Z.G, additional, Xie, Y.F, additional, Yao, L.H, additional, Yao, L.Y, additional, Zheng, Y.J, additional, Zhong, G.W, additional, Zhou, Y, additional, and Pan, C.H, additional

Published
2005
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42. Characterization of structure and properties of TiN–TiB2 nano-composite prepared by ball milling and high pressure heat treatment

Author

Qiu, L.X., Yao, B., Ding, Z.H., Zheng, Y.J., Jia, X.P., and Zheng, W.T.

Subjects
*TITANIUM nitride, *ORE-dressing, *HEAT treatment of metals, *HIGH pressure (Technology)
Abstract

Abstract: Synthesis of TiN–TiB2 nano-composite was investigated by mechanical milling of mixture of Ti and hexagonal boron nitride (h-BN) and subsequent sintering under high pressure and high temperature (HPHT). A TiN–TiB2 composite was fabricated by ball milling of the mixture for 70h and then sintering at 5GPa, 1300°C. The composite has micro-hardness of 8.8GPa and electrical resistivity of 2×10−4 Ωcm. The formation mechanism of the composite was discussed based on thermodynamics and kinetics. [Copyright &y& Elsevier]

Published
2008
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43. HPHT synthesis of diamond with high concentration nitrogen using powder catalyst with additive Ba(N3)2

Author

Yu, R.Z., Ma, H.A., Liang, Z.Z., Liu, W.Q., Zheng, Y.J., and Jia, X.

Subjects
*NITROGEN, *NATIVE element minerals, *SPECTRUM analysis, *CRYSTALLOGRAPHY
Abstract

Abstract: In this paper, high quality green industrial diamond crystals were synthesized from the system of Fe70Ni30–graphite with additive Ba(N3)2 in a china-type large volume cubic high-pressure apparatus (CHPA). FTIR spectra show that the highest nitrogen concentration in the synthesized diamond crystals is up to approximately 2400 ppm. The synthetic diamond crystals exhibit green or deep green color. The shape of synthetic crystals is mainly cub-octahedron. Partial strip crystals are also observed, which may be formed from the stretched cub-octahedron having elongated (100) and (111) crystal faces. It is also found that the synthesis conditions (temperature and pressure) increase with the increasing quantity of Ba(N3)2 additive. [Copyright &y& Elsevier]

Published
2008
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