We report studies on the magnetocaloric effect of samarium doped lanthanum manganites with different Sm-concentrations. Polycrystalline La0.7-x Sm x Ca0.30MnO3 (0≤x≤0.3) samples were prepared using the conventional solid-state reaction method with phase purity and structure confirmed using X-ray diffraction. Temperature dependent magnetization measurements and Arrott analysis reveal first order ferromagnetic transition in parent sample and second order ferromagnetic transition in doped sample with Curie temperature decreasing progressively with increasing Sm concentration from ∼182 K for x = 0.05 to 109 K for x = 0.30. A large magnetic entropy change (∼1.75 J kg-1 K-1 at 0.5 T) has been observed in La0.7Ca0.3MnO3 sample, and is greatly suppressed as a function of disorder caused by Sm doping. This is ascribed to the gradual loss of first-order ferromagnetic transition. This investigation suggests that La0.7-x Sm x Ca0.30MnO3 compounds can be used as a potential magnetic refrigerating material with wide range of temperature.

Development of analytical methods for the determination of phytosterols in whole grains is one of growing interests due to their clinical and nutritional functions in human. In this study, we examined simultaneous determination of β-sitosterol, stigmasterol and campesterol in Korean rice cultivars by liquid chromatography atmospheric chemical ionization time-of-flight mass spectrometer (LC-APCI-TOF-MS). The hulled rice samples were extracted using a modified QuE-ChERS and analyzed by LC-APCI-TOF-MS. The method was validated by low limit of detection (LOD) and limit of quantification (LOQ) values and high recovery values with low relative standard deviation (RSD). The highest concentration of sitosterol was detected in Hwasung and Undu rice cultivars, exhibiting approximately 195.5 and 191.7 mg/Kg, respectively. Stigmasterol and campesterol were detected at the highest level in Hwasung rice cultivar, giving the concentrations of approximately 70.0 and 53.9 mg/Kg, respectively. Sitosterol was determined to be a main phytosterol detected in the rice samples. Our data demonstrated that LC/APCI-TOF-MS coupled with QuEChERS method can be used as a simple tool for the determination of phytosterols in rice samples.

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The composites of (La0.7Ca0.3MnO3)0.97/(ZnO)0.03were fabricated with having different sintering temperature by conventional solid state reaction methods, and their magnetoresistance (MR) properties and electrical transport were investigated. The result of scanning electronic microscopy (SEM) and X-ray diffraction (XRD) indicated that no new phase appeared in the composites except LCMO and ZnO phases. specially, SEM results show that with increment of sintering temperature, the grain size of La0.7Ca0.3MnO3also increases, which plays a key on electrical and magnetic properties of the (La0.7Ca0.3MnO3)0.97/(ZnO)0.03composites. The electrical transport and magnetic was measured over a temperature range of 90 320K. tables etc. (2012H1B8A2026212), (NIPA-2013-H0301-13-2009)