• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.84-93
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• 2013

Validated analytical methods for isopyrazam are meager or lacking. In the present study, a single residual analytical method was developed for isopyrazam in selected commodities. Isopyrazam was analyzed in brown rice, soybean, green pepper, mandarin, cucumber, and Korean melon. We tried different solvents and methods through extraction, partition and purification steps to obtain best analytical results. For isopyrazam samples were extracted with acetonitrile, concentrated and partitioned with n-hexane, clean-up using florisil with n-hexane/ethylacetate (70/30) and analyzed with HPLC/UVD. The limit of quantitation (LOQ) for isopyrazam was 1.0 ng (S/N > 10) and method LOQ (MLOQ) was 0.04 mg $kg^{-1}$. Recovery ranged through 81.0~105.3% (syn-isomer) and 80.8~105.6% (anti-isomer) at fortification level of 0.04 (MLOQ), 0.4 (10 ${\times}$ MLOQ), and 2.0 (50 ${\times}$ MLOQ). The coefficient of variation (CV) for isopyrazam was less than 10% regardless of sample types. These results were further confirmed with LC/MS, respectively. The proposed method is highly reproducible and sensitive and is suitable for routine analysis.

• Journal of the Korean Vacuum Society
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• v.14 no.4
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• pp.222-228
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• 2005

Undoped GaN epitaxial layer was grown on c-plane sapphire substrate by a two-step growth with metalorganic chemical vapor deposition(MOCVD). We have investigated the effects of the variation of final growth temperature on surface morphology, roughness, crystal quality, optical property, and electrical property In a horizontal MOCVD reactor, the film was grown at 300 Tow low-pressure with a fixed nucleation temperature of $500^{\circ}C$, varing the final growth temperature from $850\~1050^{\circ}C$ . The undoped GaN epilayers were characterized by atomic force microscopy, high-resolution x-ray diffractometer, photoluminescence, and Hall effect measurement.

• Proceedings of the Korean Society of Crop Science Conference
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• 1987.06a
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• pp.62-63
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• 1987

• Journal of the Korean Vacuum Society
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• v.4 no.S1
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• pp.21-27
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• 1995

AI planarization 공정을 위한 barrier로서 CVD 및 PVD 방법에 의해 증착된 TiN 박막의 특성에 대하여 연구하였다. CVD TiN은 TDMAT source를 사용한 MOCVD방법으로 증착하였으며, PVD TiN은 1:1 aspect ratio(A/R)를 갖는 collimator를 사용한 reactive wputtering법으로 증착하였다. AES, SEM을 이용하여 CVD TiN과 PVD TiN의 조성을 분석하고 barrier 특성을 평가하였다. CVD TiN, PVD TiN 모두 400$\AA$의 두께와 RTA 처리에 의해서 AI planarization에 대한 양호한 barrier 특성을 확보할 수 있었다.

• Analytical Science and Technology
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• v.15 no.3
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• pp.300-316
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• 2002

The extraction methods of PBBs from environmental samples by soxhlet extraction for solid phase and liquid-liquid extraction for liquid phase were compared. After extraction, silicagel and florisil as column clean up methods were used for the comparison of cleanup efficiency with different solvent system. Also, the analytical instruments were used GC/MSD. The 22 kinds of PBBs standards were used to establish the analytical methods to perform the experiments of recoveries and detection limits in water and soil. The detection limits of PBBs represented 5~10 ng/L for water and 0.5~3.5 ng/g for soil samples, respectively. The recoveries of water samples represented 96~107% in n-hexane, dichloromethane and toluene for water, and 60~80% in combined solvent with n-hexane and acetone. The recoveries of soil sample were surveyed 67~97% in soxhlet extraction and 64~76% in ultrasonic extraction with selected solvents.

• Korean Journal of Crystallography
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• v.17 no.1
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• pp.6-9
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• 2006

Crystal structure of Bis(N-Methylphenazinium)-Tetracyanopalladate(II) hydrate has been determined by X-ray crystallography. Crystal data: $(C_{13}H_{11}N_2){_2}[Pd(cn)_4]{\cdot}H_2O$, Monocline, Space group $P2_1/b$(No=14), a=9.783(4), b=10.788(4), c=13.666(4) ${\AA},\;{\beta}=104.59(5),\;Z=2,\;V=1392.9{\AA}{^3},\;Dc=1.476gcm^{-3},\;F(000)=632,\;{\mu}=7.05cm^{-1}$. The structure was solved by Patterson method and refined by full matrix least-square methods using unit weights. The final R and S values were R=0.0257, Rw=0.0732, Rall=0.0283 and S=1.07 for 1930 observed reflections. Both cation and anion complexes are essentially planar and have dihedral angles of $10.16(4)^{\circ}$. The planar complex anions are sandwiched between slightly bent cations. The interplanar separations in one triad and between two triads are 3.419(3) and $3.402(4){\AA}$, respectively. The triads are stacked along b-axis.

• The Journal of the Acoustical Society of Korea
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• v.19 no.5
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• pp.53-59
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• 2000

In this paper, considering configuration of the earth and environment of country, it is classified a radio propagation environment Multipath propagation measuring system based on PN code correlation detection method is built to study a wave propagation characteristics of 1.95GHz. Considering the characteristic artificial structure of country, Cihwa plant superintendent area has been selected for basic and accurate measurement a radio propagation characteristic. The experiments are carried out with respect to the RMS delay Spread and the received power in the two kind of geographical areas, LOS (Line of Sight) and N-LOS (Non Line of Sight). The measurement result of that received power of LOS area is -1.6∼-28.8dBm, RMS delay spread is 0.023㎲∼0.22㎲ and received power of N-LOS area is 16∼36.5dBm and RMS delay spread is 0.068∼0.37㎲.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.388-395
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• 2009

An accelerated fatigue test is essentially required to maintain the reliability of the actual structures of KTX under operation conditions. However, actual fatigue life cannot be obtained because the conventional fatigue tests are not adequate to the real load conditions. Moreover foreign component makers have not provided data of the loading stresses (S) versus cycles at the failure (N). In this study, we suggested a deduction method of the S-N curve for establishing an accelerating test under various load levels. Load history was acquired from the field tests. A Rainflow method was used on the cycle counting of the field load data. After that, an S-N curve was obtained through the iteration process under the condition that the damage index satisfies to 1 in the Miner's rule. The deduced S-N curve was applied to the performance evaluation of Korean-made sealed knuckles compared with imports.

• Journal of the Korean Geotechnical Society
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• v.27 no.5
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• pp.45-59
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• 2011

This study introduces the diagrammatic Upper and Lower Bound (UB and LB) methods theoretically in order to derive the bearing capacity factor, $N_c$ in undrained clay and to compare with Prandtl's exact solution (1921). As a result of the theoretical study, an exact solution comes out when the UB and LB solutions are the same. In addition, the finite element analyses show that the failure loads approach to the bearing capacity factor of 5.14. Results of the FEA significantly depend on the finite element type, a number of elements, and a number of increments. From this study the exact solution defines that solutions from UB and LB are the same. However, this situation is very difficult to process, so we can confirm the exact solution as a range between UB and LB solutions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.25-31
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• 2014

When the public key e and the composite number n=pq are disclosed but not the private key d in an asymmetric-key RSA, message decryption is carried out by obtaining ${\phi}(n)=(p-1)(q-1)=n+1-(p+q)$ and subsequently computing $d=e^{-1}(mod{\phi}(n))$. The most commonly used decryption algorithm is integer factorization of n/p=q or $a^2{\equiv}b^2$(mod n), a=(p+q)/2, b=(q-p)/2. But many of the RSA numbers remain unfactorable. This paper therefore applies baby-step giant-step discrete logarithm and $2^k$-ary modular exponentiation to directly obtain ${\phi}(n)$. The proposed algorithm performs a reverse baby-step and $2^k$-ary adult-step. As a results, it reduces the execution time of basic adult-step to $1/2^k$ times and the memory $m={\lceil}\sqrt{n}{\rceil}$ to l, $a^l$ > n, hence obtaining ${\phi}(n)$ by executing within l times.