Local structure and magnetocaloric effect for La_0.7Sr_0.3Mn_1-xNi_xO₃

Zhang, Y.D.,Phan, T.L.,Yang, D.S.,Yu, S.C. Elsevier 2012 Current Applied Physics Vol.12 No.3

We have prepared polycrystalline La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>Mn<SUB>1-x</SUB>Ni<SUB>x</SUB>O<SUB>3</SUB> (x = 0, 0.01, 0.02, 0.03) samples by conventional solid-state reaction. X-ray absorption studies reveal that Ni dopants in the compounds having an oxidation state of 2+. These Ni<SUP>2+</SUP> ions replace Mn on the octahedral site of the perovskite structure. An increase of the Ni content enhances the concentration of Mn<SUP>4+</SUP> ions. This reduces magnetization, and the ferromagnetic-paramagnetic phase transition temperature (T<SUB>C</SUB>) of La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>Mn<SUB>1-x</SUB>Ni<SUB>x</SUB>O<SUB>3</SUB> from ∼365 K for x = 0 to ∼345 K for x = 0.03. The magnetocaloric effect has also been assessed by means of magnetic-entropy change, which is determined from field dependences of magnetization. We find a large magnetic-entropy change taking place around T<SUB>C</SUB> of the samples. Under an applied field interval of 15 kOe, the maximum magnetic-entropy changes |ΔS<SUB>M</SUB><SUP>max</SUP>| are about 2.33, 2.27, 2.26 and 2.21 J/kg K for x = 0, 0.01, 0.02, and 0.03, respectively. Interestingly, the doping of a small amount of Ni in La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>Mn<SUB>1-x</SUB>Ni<SUB>x</SUB>O<SUB>3</SUB> does not make|ΔS<SUB>M</SUB><SUP>max</SUP>| changed very much, but causes the shift of this value towards room temperature. Such the feature is applicable to control the working temperature range of cooling systems based on the magnetocaloric effect.

Fabrication and characterization of fluorohydroxyapatite nanocrystals/poly(d,l-lactide) composite scaffolds

L. Cheng,S.M. Zhang,P.P. Chen,S.L. Huang,L. Liu,W. Zhou,J. Liu,H. Gong,Q.M. Luo 한국물리학회 2007 Current Applied Physics Vol.7 No.s1

Poly(D,L-lactide) (PDLLA)/uorohydroxyapatite nanocrystals (nano-F-HA) porous scaolds were successfully fabricated through asolvent-casting and particulate-leaching technique. Nano-HA/PDLLA scaold and PDLLA scaold were prepared by using the sameprocess for comparison. The structure, phase and morphology of the nanocomposite scaolds were observed by SEM. The results indi-cated that F-HA nanocrystals were homogeneously dispersed in the PDLLA matrix. The porosity of the scaolds was up to 90%, andmacropores and micropores coexisted and interconnected throughout the scaolds. Cell culture experiments demonstrated that the nano-F-HA/PDLLA scaffold had the best adhesion tendency to chondrocytes among the scaffolds investigated.

Magnetic entropy change of V substituted Ni-Mn-Ga Heusler alloy

Min, S. G.,Zhang, Y. D.,Malkinski, L.,Yu, S. C.,Lee, K. W.,Kim, Y. C. American Institute of Physics 2009 JOURNAL OF APPLIED PHYSICS - Vol.105 No.7

<P>The magnetization behaviors have been analyzed for Ni54Mn21-xVxGa25 (x=0,2,4) alloys which were prepared by conventional arc melting method in argon atmosphere. The Curie temperature T-C was found to be 325, 300, and 265 K and the austenitic transition temperature T-A on heating was found to be 315, 217, and 124 K for x=0, 2, and 4, respectively. The magnetic characteristics were performed with a Quantum Design superconducting quantum interference device magnetometer in the field of up to 20 kOe. A large magnetic entropy change Delta S-M, which is calculated from H versus M curves associated with the ferromagnetic-paramagnetic transitions, has been observed. The maximum Delta S-M for an applied field of 2.0 T is 2.49, 1.92, and 1.81 J/kg K for x= 0, 2, and 4, respectively. (c) 2009 American Institute of Physics. [DOI: 10.1063/1.3072819]</P>

Sensitivity of surface characteristics on the simulation of wind-blown-dust source in North America

Park, S.H.,Gong, S.L.,Gong, W.,Makar, P.A.,Moran, M.D.,Stroud, C.A.,Zhang, J. Pergamon Press ; Elsevier [distribution] 2009 Atmospheric environment Vol.43 No.19

Recently, a wind-blown-dust-emission module has been built based on a state-of-the-art wind erosion theory and evaluated in a regional air-quality model to simulate a North American dust storm episode in April 2001 (see Park, S.H., Gong, S.L., Zhao, T.L., Vet, R.J., Bouchet, V.S., Gong, W., Makar, P.A., Moran, M.D., Stroud, C., Zhang, J. 2007. Simulation of entrainment and transport of dust particles within North America in April 2001 (''Red Dust episode''). J. Geophys. Res. 112, D20209, doi:10.1029/2007JD008443). A satisfactorily detailed assessment of that module, however, was not possible because of a lack of information on some module inputs, especially soil moisture content. In this paper, the wind-blown-dust emission was evaluated for two additional dust storms using improved soil moisture inputs. The surface characteristics of the wind-blown-dust source areas in southwestern North America were also investigated, focusing on their implications for wind-blown-dust emissions. The improved soil moisture inputs enabled the sensitivity of other important surface characteristics, the soil grain size distribution and the land-cover, to dust emission to be investigated with more confidence. Simulations of the two 2003 dust storm episodes suggested that wind-blown-dust emissions from the desert areas in southwestern North America are dominated by emissions from dry playas covered with accumulated alluvial deposits whose particle size is much smaller than usual desert sands. As well, the source areas in the northwestern Texas region were indicated to be not desert but rather agricultural lands that were ''activated'' as a wind-blown-dust sources after harvest. This finding calls for revisions to the current wind-blown-dust-emission module, in which ''desert'' is designated to be the only land-cover category that can emit wind-blown dust.

Ferromagnetic Order in Rapidly Cooled Nd-Fe-Co-Al Alloy Ribbons

Phan, T. L.,Zhang, Y. D.,Dan, N. H.,Thang, D. D.,Thanh, T. D.,Zhang, P.,Yu, S. C. IEEE 2013 IEEE transactions on magnetics Vol.49 No.7

<P>We have studied the magnetic properties of Nd<SUB>45</SUB>Fe<SUB>30</SUB>Co<SUB>15</SUB>Al<SUB>10</SUB> alloy ribbons with various thicknesses of about 120 (N<SUB>1</SUB>) and 50 μm (N<SUB>2</SUB>) prepared by melt-spinning. Structural analyses based on an X-ray diffractometer and a high-resolution transmission electron microscope revealed an existence of nanocrystals with sizes of 10 ~ 20 nm surrounded by an amorphous host matrix. With decreasing ribbon thickness and nanocrystalline size, magnetic studies upon a vibrating sample magnetometer indicated the decrease of the Curie temperature (T<SUB>C</SUB>), coercive force (H<SUB>c</SUB>), and magnetic entropy change (ΔS<SUB>m</SUB>). In the ferromagnetic region, however, magnetization values determined for N<SUB>2</SUB> are greater than those determined for N<SUB>1</SUB>. These results are related to the differences in the critical exponents of N<SUB>1</SUB> (β=0.418 and γ=1.173), and N<SUB>2</SUB> (β=0.512 and γ=1.077), which are characteristic for the ferromagnetic nature existing in the alloy ribbons with different thicknesses.</P>

Influence of Pr-doping on the magnetic properties and magnetocaloric effect of Ni_50-xPr_xMn₃₇Sn₁₃ alloys

Phan, T.L.,Thanh, P.T.,Dan, N.H.,Zhang, P.,Thanh, T.D.,Phan, M.H.,Yu, S.C. Elsevier Sequoia 2014 JOURNAL OF ALLOYS AND COMPOUNDS Vol.615 No.suppl1

We have studied the magnetic and magnetocaloric (MC) properties of Ni<SUB>50-x</SUB>Pr<SUB>x</SUB>Mn<SUB>37</SUB>Sn<SUB>13</SUB> (x=0, 1, 3, and 5) alloy ingots fabricated by arc-melting. Experimental results revealed a coexistence of the conventional and inverse MC effects in the samples with x=0, 1, and 3. There is a gradual decrease of the magnetization and magnetic-entropy change (ΔS<SUB>m</SUB>) when Pr-doping content increases. However, the Curie temperature of the austenitic phase (T<SUB>C</SUB><SUP>A</SUP>) around room temperature was not changed very much. Particularly, doping a small amount of Pr with x=1 enhances remarkably the linewidth of the peaks in its ΔS<SUB>m</SUB>(T) curves. This increases the relative cooling power (RCP) of Ni<SUB>50-x</SUB>Pr<SUB>x</SUB>Mn<SUB>37</SUB>Sn<SUB>13</SUB> alloys when they are used as coolants in refrigeration devices. For example, under an applied field of H=50 kOe, the RCP increases from 150 for x=0 to ~200J/kg for x=1. Higher Pr contents reduce quickly the MC effect because of the formation of nonmagnetic secondary phases.

Growth hormone and receptor gene mutations in Chinese Banna miniature pig

J.Z. Deng,L.L. Hao,M.T. Li,S. Lang,Y.Z. Zeng,S.C. Liu,Y.L. Zhang 한국통합생물학회 2011 Animal cells and systems Vol.15 No.4

The Banna miniature pig (BNMP) is a representative miniature pig breed in China. Even though BNMP dwarfism is obvious, its underlying causative mutations remain unknown. In this study, the BNMP and Large White pig (LWP)serum growth hormone (GH) and insulin-like growth factor (IGF-1) levels were detected by ELISA and compared. BNMP serum IGF-1 levels were significantly lower than LWP levels (P<0.05). The miniature condition may arise from mutations in the GH and GH receptor (GHR) genes. Therefore, GH and GHR cDNA from the BNMP were cloned into a pMD18-T vector by RT-PCR using the total RNA obtained from the BNMP’s pituitary and liver tissues. Sequencing results indicated that the open reading frame of the BNMP GH gene is composed of a 26-residue signal peptide and a 191-residue mature peptide. The coding sequence of the BNMP GHR gene contained 639 amino acids, including a signal peptide that is 18 amino acids long. Two amino acid substitutions, A09V and R22Q, were found in the signal peptide of the GH gene. Additionally, the S104P mutation was found in the BNMP’s mature GH protein. Four mutations in the cytoplasmic domain of GHR may influence the downstream signal transduction of GHR, which needs further experimental evidence.

Growth hormone and receptor gene mutations in Chinese Banna miniature pig

Deng, J.Z.,Hao, L.L.,Li, M.T.,Lang, S.,Zeng, Y.Z.,Liu, S.C.,Zhang, Y.L. The Korean Society for Integrative Biology 2011 Animal cells and systems Vol.15 No.4

The Banna miniature pig (BNMP) is a representative miniature pig breed in China. Even though BNMP dwarfism is obvious, its underlying causative mutations remain unknown. In this study, the BNMP and Large White pig (LWP) serum growth hormone (GH) and insulin-like growth factor (IGF-1) levels were detected by ELISA and compared. BNMP serum IGF-1 levels were significantly lower than LWP levels (P<0.05). The miniature condition may arise from mutations in the GH and GH receptor (GHR) genes. Therefore, GH and GHR cDNA from the BNMP were cloned into a pMD18-T vector by RT-PCR using the total RNA obtained from the BNMP's pituitary and liver tissues. Sequencing results indicated that the open reading frame of the BNMP GH gene is composed of a 26-residue signal peptide and a 191-residue mature peptide. The coding sequence of the BNMP GHR gene contained 639 amino acids, including a signal peptide that is 18 amino acids long. Two amino acid substitutions, A09V and R22Q, were found in the signal peptide of the GH gene. Additionally, the S104P mutation was found in the BNMP's mature GH protein. Four mutations in the cytoplasmic domain of GHR may influence the downstream signal transduction of GHR, which needs further experimental evidence.

Magnetic and Magneto-Optical Properties of Co-Sputtering FePt Films

J. Gao,B. Ma,C.L. Zha,Q.Y. Jin,S.Y. Wang,Z.Z. Zhang 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.5I

FePt thin .lms have been prepared at dierent substrate temperatures by DC magnetron co-sputtering. The .lms change from a disordered fcc structure to a L10 fct structure with temperature. The magnetic and the magneto-optical properties of those FePt .lms have been studied. The dependence of spectral changes on the formation of a chemically-ordered L10structure is observed in the polar magneto-optical Kerr rotation. In the spectra, the ultraviolet peak located in the high-energy range (4.0 { 4.5 eV), which is related to electronic transitions on Pt atomic sites, is observed for all samples. On the contrary, the peak related to transitions on Fe atomic sites, which is located in the low-energy range (1.5 { 2.0 eV), is only observed for highly chemically-ordered samples. Compared with the spectra for the L10 structure of FePt .lms pre- pared by using molecular beam epitaxy, the infrared peak related to Fe sites is shifted to low energy.

Association mapping of salinity and alkalinity tolerance in improved japonica rice (Oryza sativa L. subsp. japonica Kato) germplasm

Cui, D.,Xu, C. y.,Yang, C. g.,Zhang, Q. x.,Zhang, J. g.,Ma, X. d.,Qiao, Y. l.,Cao, G. l.,Zhang, S. y.,Han, L. z. Springer Science + Business Media 2015 Genetic resources and crop evolution Vol.62 No.4