• Korean Journal of Soil Science and Fertilizer
• /
• v.49 no.5
• /
• pp.577-583
• /
• 2016

Small-sized persimmons produced by high crop load are better accepted in the export markets. However, maintaining high crop load frequently results in weakness of tree vigor, deterioration of fruit quality, and increase of the risks for alternate bearing. This experiment was conducted to determine the combined effects of fertilization rate and leaf-fruit (L/F) ratio on container-grown 3-year-old 'Fuyu' persimmon trees. Application of 3.6-g N, 2.1-g $P_2O_5$, 2.7-g $K_2O$, 2.7-g CaO, and 0.6-g MgO was for the control fertilization rate (CF) and that of a 3-fold CF was for the high fertilization rate (HF). Commercial fertilizers were surface-applied to a container on July 6, July 17, and August 10 in three equal aliquots. Single tree for each fertilization rate was assigned for 12 L/F ratios (5, 6.3, 7.7, 9, 10.4, 13, 15.5, 18, 21, 24, 27, and 33) mostly by fruit thinning or rarely by defoliation on July 1. HF did not affect the yield, weight and soluble solids of the fruits but decreased skin color. As L/F ratio increased, yield decreased but average weight, skin color, and soluble solids of fruits increased. With HF, N and K concentrations in leaves, fruits, and shoots increased to some extent but soluble sugars in dormant shoots decreased. Many shoots were cold-injured with low L/F ratio especially at the HF. HF did not increase number of flower buds the next spring either on a shoot or on a tree basis but increased shoot length, compared with the CF. Increasing L/F ratio markedly increased number of flower buds and shoot growth the following year at both fertilization rates. Therefore, an appropriate combination of fertilization rate and L/F ratio should be necessary to maintain stable fruit production and tree vigor at high crop load.

• Journal of the Korean Magnetics Society
• /
• v.9 no.3
• /
• pp.136-142
• /
• 1999

$Ni_{0.65}Zn_{0.35}Cu_{0.3}Fe_{1.7}O_4$ has been studied with x-ray diffraction, Mossbauer spectroscopy, and vibrating sample magnetometer. The crystal structure is found to be a cubic spinel with the lattice constant $a_0=8.403{\AA}$. Mossbauer spectra of have been taken at various temperatures ranging from 12 K to 665 K. as the temperature increases toward $T_N$ a systematic line broadening effect in the Mossbauer spectrum is observed and interpreted to originate from different temperature dependencies of the magenetic hyperfine fields at various iron sites. Also, by using binomial distribution equation we obtained the hyperfine fields of tetrahedral[A] and octahedral sites[B], $H_{hf}(A)=470\;kOe,\; H_{hf}(B0)=495 \;kOe,\; H_{hf}(B1)=485\;kOe, \;H_{hf}(B2)=453\;kOe,\; H_{hf}(B3)=424\;kOe,\; H_{hf}(B4)=390\;kOe,\; H_{hf}(Bavr)=451\;kOe$ respectively at room temperature. The isomer shift indicates that the iron ions are ferric at tetrahedral[A] and octahedral sites[B], respectively. The Neel temperature is determined to be $T_N=665\;K$. The results of the VSM data gave the magnetic moment and coercivity values of $M_S=66\; emu/g\;and\;H_C=36\;Oe$.

• Korean Journal of Materials Research
• /
• v.16 no.4
• /
• pp.248-252
• /
• 2006

An investigation is reported on the coating of ZnS:Cu,Cl phosphors by $HfO_2$ using atomic layer deposition method. Hafnium oxide films were prepared at the chamber temperature of $280^{\circ}C$ using $Hf[N(CH_3)_2]_4\;and\;O_2$ as precursors and reactant gas, respectively. XPS and ICP-MS analysis showed the surface composition of coated phosphor powder was hafnium oxide. In FE-SEM analysis, the surface morphology of uncoated phosphors became smoother and clearer as the number of ALD cycle increased from 900 to 1800. The photoluminescence intensity for coated phosphors showed $7.3{\sim}13.4%$ higher than that of uncoated. The effect means that the reactive surface is uniformly coated with stable hafnium oxide to reduce the dead surface layer without change of bulk properties and also its absorptance is almost negligible due to ultrathin(nano-scaled) films. The growth rate is about $1.1{\AA}/cycle$.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.2
• /
• pp.188-194
• /
• 2013

The effects of white bread supplemented with konjac glucomannan on diet-induced obesity in rats were investigated. Four groups of male Sprague-Dawley rats were examined: a non-obese control group (NC), an obese high fat diet group (HF), an obese high fat diet group given bread supplemented with 10% konjac glucomannan (KGM1) and an obese high fat diet group given bread supplemented with 20% konjac glucomannan (KGM2). The daily weight gain of the KGM1 group increased slightly and decreased in the KGM2 group compared to the HF group. The serum triglycerides, total lipid, total cholesterol, and HDL-cholesterol increased in the HF compared to the NC group, whereas they decreased in KGM1 and KGM2 groups. After having this experimental diet for 6 weeks, the body weight in KGM1 and KGM2 groups decreased compared to the HF group. While the initial R$\ddot{o}$hrer index was 23.13 in the NC group, and 31.50~32.59 in the HF, KGM1, and KGM2 groups, the index after the experimental diets for 6 weeks was 28.39 in the NC group, 36.88 in the HF group, 33.48 in the KGM1 group and 29.64 in the KGM2 group. The level of body fat increased from 1% to 7.14% in the NC group, from 15.60% to 60.05% in the HF group, and from 10.60% to 10.83% in the KMG1 group, but decreased from 10.45% to 8.20% in the KGM2 group. These results demonstrate that white bread with glucomannan is effective in reducing body weight and serum lipids in high fat diet-induced obese rats.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.317-318
• /
• 2012

현재의 반도체 산업에서 Hafnium oxide와 Hafnium silicates같은 high-k 물질은 CMOS gate와 DRAM capacitor dielectrics로 사용하기 위한 대표적인 물질에 속한다. MOSFET (metal oxide semiconductor field effect transistor)구조에서 gate length는 16 nm 이하로 계속 미세화가 연구 중이고, 또한 gate는 기존구조에서 Multi-gate구조로 다변화가 일어나고 있다. 이를 통해 게이트 절연막은 그 구조와 활용범위가 다양해지게 될 것이다. 동시에 leakage current와 dielectric break-down을 감소시키는 연구가 중요해지고 있다. 그러나 나노 영역에서의 기계적 특성에 대한 연구는 전무한 상태이다. 따라서 복잡한 회로 공정, 다양한 Multi-gate 구조, 신뢰도의 향상을 위해서는 유전박막 물질자체와 계면에서의 물리적, 기계적인 특징의 측정이 상당히 중요해지고 있다. 이에 본 연구는 Nano-indenter의 통해 경도(Hardness)와 탄성계수(Elastic modulus) 등의 측정을 통하여 시료 표면의 나노영역에서의 기계적 특성을 연구하고자 하였다. $HfO_2$게이트 절연막은 rf magnetron sputter를 이용해 Si (silicon) (100)기판위에 박막형태로 증착하였고, 이후 furnace에서 질소분위기로 온도(400, 450, $500^{\circ}C$)를 달리하여 20분 열처리를 하였다. 또한 Weibull distribution을 이용해 박막의 characteristic value를 계산하였으며, 실험결과 열처리 온도가 $400^{\circ}C$에서 $500^{\circ}C$로 증가함에 따라 경도와 탄성계수는 7.4 GPa에서 10.65 GPa으로 120.25 GPa에서 137.95 GPa으로 각각 증가하였다. 이는 재료적 측면으로 재료의 구조적 우수성이 증가된 것으로 판단된다.

• Transactions on Electrical and Electronic Materials
• /
• v.7 no.4
• /
• pp.210-214
• /
• 2006

In this paper, two sampling methods which are Latin hypercube sampling (LHS) and simple random sampling were. compared to improve the modeling speed of neural network model. Sampling method was used to generate initial weights and bias set. Electrical characteristic data for $HfO_2$ thin film was used as modeling data. 10 initial parameter sets which are initial weights and bias sets were generated using LHS and simple random sampling, respectively. Modeling was performed with generated initial parameters and measured epoch number. The other network parameters were fixed. The iterative 20 minimum epoch numbers for LHS and simple random sampling were analyzed by nonparametric method because of their nonnormality.

• Journal of the Korean Chemical Society
• /
• v.26 no.4
• /
• pp.229-234
• /
• 1982

Using solution technique, sulfur in the sulfide ore was indirectly determined by X-ray fluorescence spectrometry. The sample was dissolved with the mixed solution of B$r_2$ and HN$O_3$, and Si$O_2$, a major constituent, was repelled from the solution by HF treatment several times, B$a^{2+}$ solution was added to the solution to precipitate the S$O^4_{2-}$ ion as BaS$O_4$. Measuring the fluorescent X-ray intensity of excess Ba2+ ion in the filtrate, the content of sulfur in the original ore was back-calculated. Comparing the results by this method with the gravimetric method, the mean difference was ${\pm}1.7%$ in the range of 20 to 40% of sulfur content and the method was tolerably reproducible.

• Proceedings of the KIEE Conference
• /
• 2006.10a
• /
• pp.34-35
• /
• 2006

Transparent ZnO thin film transistor (TFT) is fabricated on the glass substrates. The device consists of a high mobility intrinsic ZnO as a semiconductor active channel, Ga doped ZnO (GZO) as an electrode, $HfO_2$ as a gate insulator. GZO and $HfO_2$ layers are prepared by using a pulsed laser deposition and intrinsic ZnO layers are fabricated by using an rf-magnetron sputtering, respectively. The transparent TFT is highly transparent (> 87 %) and exhibits n-channel, enhancement mode behavior with a field-effect mobility as large as $11.7\;cm^2/Vs$ and a drain current on-to-off ratio of about $10^5$.

• Korean Journal of Materials Research
• /
• v.11 no.1
• /
• pp.3-7
• /
• 2001

$M\"{o}ssbauer$ spectra of the $Ni_{1+x}Ti_xFe_{2-2x}O_4$ systems ($0{\leqq}x{\leqq}0.7$), which appear as single phase spinel structure, were examined at RT. The $M\"{o}ssbauer$ spectra reveal two sextet for $0{\leqq}x{\leqq}0.3$, two sextet and a doublet for $0.4{\leqq}x{\leqq}0.6$, and a doublet for x=0.7 As x increases, the area ratio of B-site and A-site($A_B/A_A$) of the sextet decreases, and the area ratio of the doublet and the total areas($A_{doublet}/A_{tot.}$) increases. The isomer shift(I.S.) of A-site slightly increases and magnetic hyperfine fields($H_{hf}$) of two sites decrease as the increasing x. From these results, we have obtained the cation distributions of the samples and concluded that the increasing x leads to the decrease of covalency of $Fe^{3+}-O^{2-}$ bond in A-sites and A-B superexchange interactions.eractions.

• Korean Journal of Materials Research
• /
• v.11 no.8
• /
• pp.629-635
• /
• 2001

To improve the ductility of $A1_3Hf$ intermetallics, which are the potential high temperature structural materials, the mechanical alloying behavior. the effect of Cu addition on the $Ll_2$ phase formation and the behavior of vacuum hot-pressed consolidation were investigated. During the mechanical alloying by SPEX mill, the $Ll_2 A1_3Hf$ intermetallics with the grain size of 7~8nm was formed after 6 hours of milling in Al-25at.%Hf system. The $Ll_2$ Phase of Al_3Hf$ intermetallics with the addition of 12.5at.%Cu, similar to that of the binary Al-25at.% Hf, was formed, but the milling time necessary for the formationof the $Ll_2$ phase was delayed form 6 hours to 10 hours. The lattice parameter of ternary $Ll_2(Al+Cu)_3Hf$ intermetallics decreased with the increase of Cu content. The onset temperature of $Ll_2$ to $D0_{23}$ phase in $Al_3Hf$ intermetallics was around 38$0^{\circ}C$, the temperature upon completion varied from 48$0^{\circ}C$ to 5$50^{\circ}C$ as the annealing time. The onset temperature of $Ll_2$ to $D0_{23}$ phase transformation in $(Al+ Cu)_3Hf$ intermetallics increased with the amount of Cu and the highest onset temperature of $700^{\circ}C$ was achieved by the Cu addition of 10at.%. The relative density increased from 89% to 90% with the Cu addition of 10at.% in $Al_3Hf$ intermetallics hot-pressed in vacuum under 750MPa at 40$0^{\circ}C$ for 3 hours. The relative density of 92.5% was achieved without the phase transformation and the grain growth as the consolidation temperature increased from 40$0^{\circ}C$ to 50$0^{\circ}C$ in $(Al+Cu)_3Hf$ intermetallics hot-pressed in vacuum under 750MPa for 3 hours.