Hong Seung Kim

Starch Source Evaluation in Calf Starter: II. Ruminal Parameters, Rumen Development, Nutrient Digestibilities, and Nitrogen Utilization in Holstein Calves

Ruminal parameters, rumen development, nutrient digestibilities, and N utilization were estimated in Holstein calves fed starch from different sources. Ground corn, ground barley, ground wheat, and crimped oats were used to formulate 4 isostarch (25% of starter dry matter) pelleted diets. These diets were randomly allocated to calves (16 calves per treatment, 8 female and 8 male) and fed ad libitum along with mixed grass hay throughout the experiment. Ruminal contents and blood were sampled at d 35, 50, and 70 of age to estimate ruminal parameters and plasma beta-hydroxybutyrate, respectively. At d 70, twenty-four male calves (6/treatment) were randomly selected, euthanized, and forestomach weight, papillae length (PL), papillae width (PW), rumen wall thickness (RWT), and papillae concentration were measured. At d 63, twenty-four female calves (6/treatment) were randomly selected and moved to metabolism stalls to estimate total tract apparent nutrient digestibilities and N utilization. Female calves were given 2 wk for adaptation to experimental facilities and then total collections of feces and urine were made from d 77 to 84 of age. Ruminal pH at d 35 of age was higher in calves fed corn and oat diets than in those fed barley and wheat diets. Ruminal pH at d 50 and 70 of age was the lowest in calves on barley diets followed by those on oat and wheat diets and then by those on the corn diet. Ruminal total volatile fatty acid concentrations at d 35 of age were greatest in calves fed corn or wheat diets followed by those fed barley and oat diets. Calves on corn and wheat diets maintained greater ruminal volatile fatty acids concentrations at d 50 and 70 of age. Ruminal ammonia, acetate, propionate, butyrate, and blood beta-hydroxybutyrate concentrations were also greater in calves on the corn and wheat diets. Full and empty weights of forestomach, PL, PW, RWT, and papillae concentrations were greater in calves on corn and wheat diets. Daily average intake of nutrients (dry matter, crude protein, neutral detergent fiber, starch, Ca, and P) was greater in calves fed corn and wheat diets than in those fed barley and oat diets. Starch source did not influence the total tract apparent digestibilities of nutrients in calves. Daily N retention (g/d) was greatest on the corn diet followed by the wheat diet and then the barley and oat diets. In conclusion, calves on a corn diet have greater ruminal capacity to accommodate feed bulk. More physically and metabolically functional rumens in calves on corn and wheat diets probably resulted in greater feed consumption and N retention.

Structural and luminescence characteristics of post-annealed ZnO films on Si (111) in H2O ambient

This letter reports the effects of post thermal annealing in H2O on the structural and optical properties of Zinc oxide (ZnO) films deposited on Si substrate. The properties were investigated by atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) measurements. Our experiments demonstrated that ZnO films have better crystal quality at high annealing temperatures and there are no emission peaks even at the visible region of ZnO films annealed at 900°C. After annealing at 900°C, however, the surface roughness was increased, which seems to have been caused by re-evaporation, and the thick SiO2 and Zn-Si-O mixed layer was formed between the ZnO film and the Si substrate.

Effects of Dietary Scutellaria baicalensis Extract on Growth, Feed Utilization and Challenge Test of Olive Flounder ( Paralichthys olivaceus )

Effects of dietary Scutellaria baicalensis extract (SBE) on growth, feed utilization and challenge test of olive flounder (Paralichthys olivaceus) were determined. Six hundred thirty fish averaging 5.0 g were distributed into 18, 180-L tanks. Six experimental diets were prepared in triplicate: SBE-0, SBE-0.5, SBE-1, SBE-2, SBE-3 and SBE-5 diets containing SBE at the concentrations of 0, 0.5, 1, 2, 3 and 5%, respectively. Fish were hand-fed to apparent satiation twice a day for 8 wks. At the end of 8-wk feeding trial, ten fish from each tank were infected by Edwardsiella tarda for challenge test. Survival and weight gain of fish were not affected by dietary concentrations of SBE. However, specific growth rate of fish fed the SBE-2 diet was higher than that of fish fed the SBE-0, SBE-1, SBE-3 and SBE-5 diets. Neither feed efficiency nor serum chemical composition of fish was affected by dietary concentrations of SBE. The cumulative mortality of fish fed the SBE-0 diet was 100% at 96 h after E. tarda infection, but 77 to 87% for fish fed the other diets. Dietary inclusion of 2% SBE appears to be recommendable to improve specific growth rate of fish and SBE had the potential to mitigate mortality of fish at E. tarda infection.

Characterization of Thermal Annealed n-ZnO/p-GaN/Al2O3

This paper reports the effects of post thermal annealing in air and N2 on the structural and optical properties of zinc oxide (ZnO) films deposited on a p-GaN substrate. The properties of annealed ZnO/GaN/Al2O3 films were investigated by atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), and Auger electron spectroscopy (AES). Our experiments demonstrated that the ZnO film annealed in N2 had better structural properties than as-deposited ZnO film. When annealed in air, the optical property of ZnO film was improved by the oxygen from ambient air, although the structural properties were somewhat poor and the interface of ZnO and GaN was degraded by the formation of a Ga–O mixed phase.

Effect of Post Annealing of ZnO Buffer Layer on the Properties of Hydrothermally Grown ZnO Nanorods

We investigated the effect of an annealed ZnO buffer layer on the structural and optical properties of hydrothermally grown ZnO nanorods. ZnO buffer layers were deposited on a p-type Si(100) substrate by radio-frequency (RF) sputtering. ZnO nanorods were grown on as-deposited and annealed ZnO buffer layers by a hydrothermal process at a low temperature for various growth times. Annealed ZnO buffer layers have higher c-axis texturing than as-deposited ZnO buffer layer. ZnO nanorods grown on annealed ZnO buffer layers had higher X-ray diffraction (002) peak intensities and ultraviolet (UV) emission intensities than those grown on the as-deposited ZnO buffer layer. The degree of c-axis texturing of ZnO buffer layer affects the perpendicular growth for hydrothermal ZnO nanorod.

Schottky Diodes Prepared with Ag, Au, or Pd Contacts on a MgZnO/ZnO Heterostructure

We successfully fabricated lateral Schottky diodes with a thin MgZnO layer inserted between the ZnO and Schottky contact metal layers. The MgZnO/ZnO heterostructure was deposited onto a c-sapphire substrate by pulsed laser deposition using Mg0.3Zn0.7O and ZnO targets. Ti/Au was used to achieve ohmic contact with the Mg0.3Zn0.7O thin film layer, whereas Schottky contacts were prepared using silver (Ag), gold (Au), and palladium (Pd). The Ag Schottky diode devices exhibited rectification ratios as high as ~103 at a bias voltage of ±1 V, with an ideality factor of 2.37 and a work function of 0.73 eV. The possibility of preparing Schottky contacts with a high carrier concentration on the ZnO layer is discussed as a function of the presence or absence of a MgZnO thin layer and in terms of the measured current–voltage properties.

Effect of Indium Mole Fraction on the Diode Characteristics of ZnO:In/p-Si(111) Heterojunctions

We investigated the effect of indium (In) doping (0.6, 1, 5, and 10 at. %) on the diode characteristics of heterostructures consisting of In-doped ZnO films on p-Si(111) substrates. In-doped ZnO films were deposited by pulsed laser deposition with an In-doped ZnO target, and heterojunction diodes were fabricated by photolithography and a lift-off method. The electrical properties of ZnO films were altered by In doping, with the In (10 at. %)-doped ZnO film having the highest electron concentration (3.0×1019 cm-3) and lowest resistivity (1.5×10-2 Ωcm) of the analyzed ZnO films. In doping also had a strong effect on diode characteristics. In particular, In-doped ZnO/p-Si diodes show a very low reverse current density of approximately 2.8×10-6 A/cm2 (In 10 at. %) at -5 V and a high on–off ratio (In 10 at. %) of about 2.5×10-6 at ±5 V. The heterostructure diodes exhibited typical current–voltage characteristics with turn-on voltages in the range 1.2–2.4 V and series resistances in the range 37–99 Ω. The modified diode characteristics may be related to changes in the ZnO film structure induced by In doping. We also discuss the effect on diode characteristics of In doping of ZnO films.

Synthesis and Electrochemical Evaluation of Li, Mn-Rich Cathode Materials for Advanced Lithium Batteries.

Li2MnO3-based composite, xLi2MnO3-(1--x)LiMO2 (M = Ni, Co, Mn, etc.), was synthesized via co-precipitation with sintering treatment. The composite material has hexagonal structure including a little of monoclinic with a nano-crystallite size. As a result, the material showed a specific redox behavior in the voltage range of 2.0-4.6 V and approximately 267 mAh/g of discharge capacity was obtained at the room temperature.

The Characteristics of ZnO Nanorods According to Growth Concentration on PES Substrate

In particular, the PES substrate, the crystal structure of the amorphous as well as the surface morphology is not good. So research of thin films growth for epitaxial growth by the use of a buffer layer on the amorphous PES substrate is essential. Therefore, in this study, we deposited ZnO thin-film on PES substrate, and grown ZnO nanorods at various ZnO concentrations during 1 hour. We used SEM, XRD, and HP 4145B for observe the structural and electrical characteristics of ZnO nanorods. UV-visible spectrometer was used to get the band gap and transmittance.

A Study of Stacked Buffer Layers for the Epitaxial Growth of Zn0.58Mg0.42O Films on c-Sapphire by Pulsed Laser Deposition

We report the growth of hexagonal Zn0.58Mg0.42O thin films on a c-plane sapphire substrate via pulsed laser deposition using Zn0.7Mg0.3O/Zn0.9Mg0.1O/ZnO stacked buffer layers of various thicknesses. The effects of the stacked buffer layer thickness on the structural and optical properties were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), energy dispersive X-ray (EDX), and UV–visible spectroscopy. The XRD results showed that whereas the cubic and hexagonal phases formed without a stacked buffer layer, only the hexagonal Zn0.58Mg0.42O phase grew in the stacked buffer layer configuration. The stacked buffer layer could accommodate structural inconsistencies and prevent phase separation in high-Mg films. As the thickness of each stacked buffer layer decreased, the crystalline quality of the hexagonal Zn0.5Mg0.5O film was enhanced.