• Journal of Magnetics
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• v.19 no.2
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• pp.116-120
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• 2014

The spin-lattice relaxation time, $T_1$, for $^{69}Ga$, $^{71}Ga$, and $^{75}As$ nuclei in GaAs:$Mn^{2+}$ single crystals was measured as a function of temperature. The values of $T_1$ for $^{69}Ga$, $^{71}Ga$, and $^{75}As$ nuclei were found to decrease with increasing temperature. The $T_1$ values in GaAs:$Mn^{2+}$ crystal are similar to those in pure GaAs crystal. The calculated activation energies for the $^{69}Ga$, $^{71}Ga$, and $^{75}As$ nuclei are 4.34, 4.07, and 3.99 kJ/mol. It turns out that the paramagnetic impurity effect of $Mn^{2+}$ ion doped in GaAs single crystal was not strong on the spin-lattice relaxation time.

• Journal of the Korean Ceramic Society
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• v.18 no.3
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• pp.187-191
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• 1981

The effect of additions, $TiO_2$ and $ZrO_2$ as nucleant on the base glass which composition was determined to 0.97 $Li_2O-Al_2O_3-SiO_2$ has been investigated by means of D.T.A., X-ray diffraction and dilatation. $TiO_2$ and $ZrO_2$ as nucleant were added 0.06mole, in which ratios of $TiO_2$/$ZrO_2$ were varied 1/0, 2/1, 1/1, 1/2 and 0/1. The crystalline phases were appeared to $\beta$-spodumene as principal, $\beta$-eucryptite and $ZrO_2$ as secondary, regardless of nucleant variations. The crystallinity of the crystallized glass added $TiO_2$, $ZrO_2$ mixture as nucleant was higher than that of the glass added $TiO_2$ or $ZrO_2$ only. The crystallinity of the glass added $TiO_2$/$ZrO_2$ =1/1 was highest. Increasing the addition of $ZrO_2$, it has been observed that the crystal growing temperature became higher.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.8
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• pp.316-322
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• 1986

In this paper, the photodoping effect on the interface of Ag-amorphous As2S3 thin film has been investigated by measuring the resistance change of the Ag layer, the absorption coefficient of the As2S3, the optical density of As2S3 layer and the short-circuit photocurrents under light irradiation. As the experimental results, the photodissolution rate and the photodiffusion rate depends on the magnitude of photon energy absorbed in the As2S3. The sensitivity limit of the photodissolution rate at Ag layer was about 630[nm] and the sensitivity limit of the photodiffusion rate at the Ag-As2S3 interface was about 680[nm]. Also, it was found that the depth of photodiffusion was proportional to the square root of exposing time.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.5
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• pp.375-379
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• 1991

Formation of TiAs precipitate through the reaction between TiSi2 with C54 structure and heavily doped arsenic ion in poly-silicon, and influence of TiSAs and silicon distribution resulted from the reaction TiSi2+As ->2Si on the morphology degradation have been studied.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.2
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• pp.177-186
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• 1997

A field experiment was conducted to evaluate growth characteristics, dry matter yield and crude protein yield according to different planting dates at sorghum $\times$ sudangrass hybrid(SSH) and soybean intercropping. Planting dates were five treatment of may 6(Tl), may 13(T2), may 20(T3), may 27(T4) and june 3(T5), and cutting frequency was two times a year. 1. Plant length of SSH was the highest at T2 as 253cm, but T5 was the shortest as 203cm. In the soybean, T3 and T4 were the highest as 113cm, respectively. Leaf length of SSH was high at T5. In the soybean, T2 was the highest as 17cm. Average leaf width of T2, T3 and T4 was higher than TI and T5. 2. Leaf number of T3(SSH and soybean) was higher than other treatments, Stem diameter of SSH and soybean showed the highest as 12.3mm and 8.6mrn at T5 and T3, respectively. In the SSY mean stem hardness of TI was the highest as 2.5kg/$cm^2$, but soybean was the highest at T1(8.0kg/$cm^2$) 3. Deed stubble according to move seeding date of SSH were 11.4 percentage at TI, and 3.9 percentage at T5 treatment. 4. Total dry matter yield according to move seeding date was the highest at T3 as 20,937kghq but T5 of late seeding was the lowest as 16,04Okgha(P < 0.05). 5. In the first cutting time, protein content of SSH was the highest at T3 as 9.9 percentage, but T1 was the lowest as 8.4 percentage. In the 2nd cutting, T5 was the highest as 8.7% but T1 was the lowest as 6.2%. In the soybean, T5 was the highest as 19.4% but TI of early seeding was the lowest as 16.2 percentage. Crude protein yield was the highest at T3 as 2,233.5kghq but TI of early seeding was the lowest as 1,579.7kgha (P < 0.05). As mentioned above the results, T2(may 13), T3(may 20) and T4(may 27) treatment could be recommended as the best suitable seeding date when drymatter and protein yield were considered.

• Toxicological Research
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• v.16 no.3
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• pp.211-219
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• 2000

The therapeutic effect of AS2-006A, a derivative of asiaticoside, has been studied and is being developed as a new wound-healing agent. In the present study, the general pharmacological effects on 1) central nervous system, 2) autonomic nervous system, 3) respiratory system, 4) gastrointestinal system. 5) cardiovascular system. and 6) urinary system were assessed in experimental animals and in in vitro models. 1. In vivo animal study: External applications of the 1 % gel ointment of AS2-006A to rats at the doses of 200. 600 or 2000 mg/kg body weight showed no observable pharmacological effects. The effects on the central nervous system were assessed by observation of behavior, hexobarbital-induced sleeping time, pentetrazole-induced convulsion assay, body temperature measurements, and observations on spontaneous activity and catalepsy. The gel ointment exhibited no effects on the cardiovascular system (i.e. blood pressure and heart rate), renal physiology (i.e. urine volume and electrolytes excretion) and gas-trointestinal physiology (i.e. intestinal charcoal propulsion and gastric mucosal irritation). 2. In vitro experiments: The effects of AS2-006A on the physiology of smooth and cardiac muscles were assessed. Muscle contractions were isotonically and isometrically measured in organ chambers using a physiograph. Cumulative additions of AS2-006A (10$^{-9}$ -10$^{-5}$ M) induced no changes in the tension of isolated guinea pig ileum and tracheal muscles. AS2-006A only slightly increased contractility of rat atrial and papillary muscles at 10$^{-2}$ M, which was not statistically different from control. These data showed that the gel ointment of AS2-006A could be externally applied as a wound-healing agent with no potential side effects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.382-385
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• 2003

Chemical mechanical polishing(CMP) is an essential process in the production of copper-based chips. On this work, the stability of Hydrogen Peroxide($H_2O_2$) as oxidizer of Cu CMP slurry has been investigated. $H_2O_2$ is known as the most common oxidizer in Cu CMP slurry. Copper slowly dissolves in $H_2O_2$ solutions and the interaction of $H_2O_2$ with copper surface had been studied in the literature. Because hydrogen peroxide is a weak acid in aqueous solutions, a passivation-type slurry chemistry could be achieved only with pH buffered solution.[1] Moreover, $H_2O_2$ is so unstable that its stabilization is needed using as oxidizer. As adding KOH as pH buffering agent, stability of $H_2O_2$ decreased. However, stability went up with putting in small amount of BTA as film forming agent. There was no difference of $H_2O_2$ stability between KOH and TMAH at same pH. On the other hand, $H_2O_2$ dispersion of TMAH is lower than that of KOH. Furthermore, adding $H_2O_2$ in slurry in advance of bead milling lead to better stability than adding after bead milling. Generally, various solutions of phosphoric acids result in a higher stability. Using Alumina C as abrasive was good at stabilizing for $H_2O_2$; moreover, better stability was gotten by adding $H_3PO_4$.

• Journal of the Korean Ceramic Society
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• v.32 no.9
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• pp.1040-1046
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• 1995

The formation free energy of Y2Cu2O5 was measured by the partial ion exchanged (Cu2+, Na+)-$\beta$/$\beta$"-Al2O3 as solid state electrolyte. The formation cell was built as follows: Pt(O2)/Y2Cu2O5＋Y2O3//(Cu2+, Na+)-$\beta$/$\beta$"-Al2O3//CuO/(O2)Pt The virtual formation formation formula, and the calculated formation free energy of Y2Cu2O5 as a function of temperature are as follows: 2CuO＋Y2O3=Y2Cu2O5 ΔfG0/kJ.mol-1=13.19-16.25*10-3T/K.5*10-3T/K.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.5-8
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• 2000

This paper shows the high performance as a photodetector of InGaP/GaAs HPT with 3-terminal caused by its inherent good electrical properties compared with AIGaAs/GaAs HPT. InGaP/GaAs HPT produced the high optical gain of about 61 where HPT is biased at Vc=3V, Iв=2${\mu}\textrm{A}$ with an input optical power of 1.23㎼. This is 2.5 times higher than that of AIGaAs/GaAs HPT. And we examined that the optical gain of HPTs becomes larger when operating in 3-terminal configuration rather than 2-terminal with the floating base. for a given base current of 2${\mu}\textrm{A}$, the optical gain is enhanced about 18% in the InGaP/GaAs HPT and about 27% in the AIGaAs/GaAs HPT over that of the 2-terminal device.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.10
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• pp.1202-1208
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• 1988

The electron density and electronic states in n- AlGaAs/GaAs heterointerface are calculated by using classical- and quantum-mechanics, respectively. We examine the effects of spacer layer thickness and doping concentration in AlGaAs layer on 2DEG density. Also, the dependences of electronic states of 2DEG upon temperature and acceptor concentration in GaAs layer are investigated.