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.

Magnetocaloric and critical behavior in the austenitic phase of Gd-doped Ni₅₀Mn₃₇Sn₁₃ Heusler alloys

Zhang, P.,Phan, T.L.,Dan, N.H.,Thanh, T.D.,Yu, S.C. Elsevier Sequoia 2014 Journal of alloys and compounds Vol.615 No.suppl1

The magnetic phase transition behavior were investigated in detail in Ni<SUB>50-y</SUB>Gd<SUB>y</SUB>Mn<SUB>37</SUB>Sn<SUB>13</SUB> (y=1 and 3) alloys prepared by arc-melting method. The martensite phase was found to be strongly suppressed by a small amount of Gd doping. Based on isothermal magnetization curves around Curie temperature of the austenite (T<SUB>C</SUB><SUP>A</SUP>) phase, critical behavior in the austenite phases of both alloys were determined carefully by the Kouvel-Fisher method. The critical exponents were found to be β=0.473+/-0.020 and γ=1.141+/-0.017 with T<SUB>C</SUB><SUP>A</SUP>=299.0+/-0.2K for y=1, and β=0.469+/-0.068 and γ=1.214+/-0.042 with T<SUB>C</SUB><SUP>A</SUP>=302.9+/-0.7K for y=3, respectively. The values of the critical exponents for the ferromagnetic phase transition in the A phase of two alloys can be basically ascribed in the mean-field model (with β=0.5, γ=1) with slightly deviation, revealing a long-range order of ferromagnetic interactions. Such critical behavior can be attributed to the magnetic inhomogeneities originated from the atomic disorder introduced by Gd doping.

Measurement ofD0−D¯0mixing and search for indirectCPviolation usingD0→KS0π+π−decays

Peng, T.,Zhang, Z. P.,Abdesselam, A.,Adachi, I.,Aihara, H.,Arinstein, K.,Asner, D. M.,Aulchenko, V.,Aushev, T.,Ayad, R.,Bakich, A. M.,Bala, A.,Bhardwaj, V.,Bhuyan, B.,Bobrov, A.,Bondar, A.,Bonvicini, American Physical Society 2014 PHYSICAL REVIEW D - Vol.89 No.9

We report a measurement of D-0-(D) over bar(0) mixing parameters and a search for indirect CP violation through a time-dependent amplitude analysis of D-0 -> K-S(0)pi(+)pi(-) decays. The results are based on 921 fb(-1) of data accumulated with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. Assuming CP conservation, we measure the mixing parameters x = (0.56 +/- 0.19(-0.09-0.09)(+0.03+0.06))% and y = (0.30 +/- 0.15(-0.05-0.06)(+0.04+0.03))%, where the errors are statistical, experimental systematic, and systematic due to the amplitude model, respectively. With CP violation allowed, the parameters vertical bar q/p vertical bar = 0.90(-0.15-0.04-0.05)(+0.16+0.05+0.06) and arg(q/p) = (- 6 +/- 11 +/- 3(-4)(+3))degrees are found to be consistent with conservation of CP symmetry in mixing and in the interference between mixing and decay, respectively.

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.

The clonal origins of leukemic progression of myelodysplasia

Kim, T,Tyndel, M S,Kim, H J,Ahn, J-S,Choi, S H,Park, H J,Kim, Y-k,Yang, D-H,Lee, J-J,Jung, S-H,Kim, S Y,Min, Y H,Cheong, J-W,Sohn, S K,Moon, J H,Choi, M,Lee, M,Zhang, Z,Kim, D(D H) Nature Publishing Group 2017 Leukemia Vol.31 No.9

<P>The genetics behind the progression of myelodysplasia to secondary acute myeloid leukemia (sAML) is poorly understood. In this study, we profiled somatic mutations and their dynamics using next generation sequencing on serial samples from a total of 124 patients, consisting of a 31 patient discovery cohort and 93 patients from two validation cohorts. Whole-exome analysis on the discovery cohort revealed that 29 of 31 patients carry mutations related to at least one of eight commonly mutated pathways in AML. Mutations in genes related to DNA methylation and splicing machinery were found in T-cell samples, which expand at the initial diagnosis of the myelodysplasia, suggesting their importance as early disease events. On the other hand, somatic variants associated with signaling pathways arise or their allelic burdens expand significantly during progression. Our results indicate a strong association between mutations in activated signaling pathways and sAML progression. Overall, we demonstrate that distinct categories of genetic lesions play roles at different stages of sAML in a generally fixed order.</P>

Spontaneous structural distortion of the metallic Shastry-Sutherland system DyB4 by quadrupole-spin-lattice coupling

Sim, Hasung,Lee, Seongsu,Hong, Kun-Pyo,Jeong, Jaehong,Zhang, J. R.,Kamiyama, T.,Adroja, D. T.,Murray, C. A.,Thompson, S. P.,Iga, F.,Ji, S.,Khomskii, D.,Park, Je-Geun American Physical Society 2016 Physical Review B Vol.94 No.19

<P>DyB4 has a two-dimensional Shastry-Sutherland (Sh-S) lattice with strong Ising character of the Dy ions. Despite the intrinsic frustrations, it undergoes two successive transitions: a magnetic ordering at T-N = 20K and a quadrupole ordering at T-Q = 12.5K. From high-resolution neutron and synchrotron x-ray powder diffraction studies, we have obtained full structural information on this material in all phases and demonstrate that structural modifications occurring at quadrupolar transition lead to the lifting of frustrations inherent in the Sh-S model. Our paper thus provides a complete experimental picture of how the intrinsic frustration of the Sh-S lattice can be lifted by the coupling to quadrupole moments. We show that two other factors, i.e., strong spin-orbit coupling and long-range Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in metallic DyB4, play an important role in this behavior.</P>

Effects of Keratinase on Performance, Nutrient Utilization, Intestinal Morphology, Intestinal Ecology and Inflammatory Response of Weaned Piglets Fed Diets with Different Levels of Crude Protein

Wang, D.,Piao, X.S.,Zeng, Z.K.,Lu, T.,Zhang, Q.,Li, P.F.,Xue, L.F.,Kim, S.W. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.12

Two experiments were conducted to investigate the in vitro ability of keratinase to hydrolyze soybean glycinin and ${\beta}$-conglycinin and to evaluate the in vivo effects of keratinase when included in corn-soybean diets with different levels of crude protein and fed to nursery pigs. In experiment 1, a saturated keratinase solution (1 ml) was added to two blank controls of either glycinin or ${\beta}$-conglycinin resulting in the hydrolysis of 94.74% glycinin and 88.89% ${\beta}$-conglycinin. In experiment 2, 190 pigs (8.3${\pm}$0.63 kg BW) were allotted to one of four treatments in a 2${\times}$2 factorial arrangement on the basis of body weight, and sex was balanced among the pens. The effects of crude protein (19 vs. 22%) and keratinase (0 vs. 0.05%) were studied. Each treatment was applied to six pens with seven (two pens) or eight pigs per pen. Pigs were fed the experimental diets for 21 d. Weight gain and feed conversion ratio were improved (p<0.05) with keratinase supplementation while feed intake was reduced (p<0.05). Keratinase supplementation increased (p<0.05) the apparent total tract digestibility of dry matter, energy, crude protein and phosphorus. Keratinase supplementation also increased n-butyric acid in the cecum and colon, lactobacilli and total anaerobe counts in the colon as well as the ratio of villus height to crypt depth in the ileum. Additionally, fecal score, ammonia nitrogen and branch chain volatile fatty acids in the colon, E. coli and total aerobe counts in the colon, crypt depth in the jejunum and ileum as well as serum interleukin-1 and interleukin-6 concentrations were also decreased (p<0.05) by keratinase supplementation. A reduction in dietary crude protein decreased (p<0.05) colon ammonia nitrogen concentration and cecal propionic acid and branch chain volatile fatty acid concentrations. In addition, cecal E. coli counts, colon total anaerobe counts, ileal crypt depth, and serum interleukin-1 and interleukin-6 concentrations were also decreased (p<0.05) with the reduction of dietary crude protein. With the exception of fecal scores, there were no significant interactions between crude protein and keratinase. This study provides evidence that dietary keratinase supplementation improved nursery pig performance by improving intestinal morphology and ecology, thus improving nutrient digestibility and alleviating the inflammatory response.

Long-lived K isomer and enhanced γ vibration in the neutron-rich nucleus ¹⁷²Dy: Collectivity beyond double midshell

Watanabe, H.,Zhang, G.X.,Yoshida, K.,Walker, P.M.,Liu, J.J.,Wu, J.,Regan, P.H.,Soderstrom, P.A.,Kanaoka, H.,Korkulu, Z.,Lee, P.S.,Nishimura, S.,Yagi, A.,Ahn, D.S.,Alharbi, T.,Baba, H.,Browne, F.,Bruce North-Holland Pub. Co 2016 Physics letters. Section B Vol.760 No.-

The level structure of <SUP>172</SUP>Dy has been investigated for the first time by means of decay spectroscopy following in-flight fission of a <SUP>238</SUP>U beam. A long-lived isomeric state with T<SUB>½</SUB>=0.71(5) s and K<SUP>π</SUP>=8<SUP>-</SUP> has been identified at 1278 keV, which decays to the ground-state and γ-vibrational bands through hindered electromagnetic transitions, as well as to the daughter nucleus <SUP>172</SUP>Ho via allowed β decays. The robust nature of the K<SUP>π</SUP>=8<SUP>-</SUP> isomer and the ground-state rotational band reveals an axially-symmetric structure for this nucleus. Meanwhile, the γ-vibrational levels have been identified at unusually low excitation energy compared to the neighboring well-deformed nuclei, indicating the significance of the microscopic effect on the non-axial collectivity in this doubly mid-shell region. The underlying mechanism of enhanced γ vibration is discussed in comparison with the deformed Quasiparticle Random-Phase Approximation based on a Skyrme energy-density functional.

Crossover from first-order to second-order phase transitions and magnetocaloric effect in La_0.7Ca_0.3Mn_0.91Ni_0.09O₃

Phan, The-Long,Zhang, P.,Thanh, T. D.,Yu, S. C. American Institute of Physics 2014 Journal of Applied Physics Vol.115 No.17

We have prepared La0.7Ca0.3Mn0.91Ni0.09O3 and then studied its critical behavior and magnetocaloric effect. Analyzing temperature and field dependences of magnetization around the ferromagnetic-paramagnetic transition reveals the sample undergoing the second-order magnetic phase transition with the critical parameters T-C approximate to 199.4K, beta = 0.171 +/- 0.006, and gamma = 0.976 +/- 0.012. A considerable difference of these critical exponents compared with those expected for the standard models is due to the sample exhibiting the crossover property (tricriticality); its exponent values are more close to those expected for the tricritical mean-field theory with beta = 0.25 and gamma = 1. Under the field 40 kOe, the maximum magnetic entropy change (-Delta S-max) around T-C is about 7.1 J center dot kg(-1)center dot K-1, corresponding to a refrigerant capacity RC approximate to 170 J/kg. Particularly, its magnetic-field dependence obeys a power law vertical bar Delta S-max vertical bar infinity H-n, where n = 0.55 is quite far from the value calculated from the relation n = 1 + (beta - 1)/(beta + gamma). (C) 2014 AIP Publishing LLC.