• 한국물환경학회지
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• 제28권5호
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• pp.729-742
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• 2012

Recently, to using chemical coagulation process for T-P removal in STP effluent as tertiary treatment process is generalized in the country. The importance of analysis technique to save the treatment & maintenance cost during coagulation process is becoming more increased each day. Thus, it is necessary for the analysis technique during coagulation process to be presented well the characteristic of coagulation in field apply. There are a few analysis techniques such as Jar Test, zeta potential analysis and streaming current detecting techniques. But there are difficult to apply in field immediately due to long test time and difficult analysis techniques. And using PDA technique, it is reviewed applicability of the techniques as field index on pilot plant of P-CAP system The P-CAP system is composed of an in-line static mixer, a Flocculation Tank and the CAP reactor with 2 stage weir for effluent. Pre-test is performed to fix the mixing velocity in the Flocculation Tank using the PDA equipment and it fixed with 30RPM. Also, Jar Test is performed to select optimum dose of each coagulant for each T-P concentration level of influent. Result of continuous test on pilot plant of P-CAP system, the FSI in the Flocculation Tank is increased consistently by increasing each dosing concentration of coagulant such as LAS and PAC in the low level influent T-P concentration comparatively. It is considered that formed Al-hydroxide complexes for dosed coagulant are caused FSI variation. Furthermore, it seems that FSI value in the high level influent T-P concentration appeared lower than the opposite influent condition relatively because it is formed simultaneously Al-hydroxide complexes as solid type and Al-phosphorus complexes as soluble type. Thus, relation of FSI by PDA technique and T-P removal of final effluent on pilot plant of P-CAP system are very limited for the kind of coagulant and the characteristics of influent. And it though that FSI value by PDA technique with analyzing of turbidity in Flocculation Tank will be used restrictedly on field as the relative field-index.

• 분석과학
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• 제15권5호
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• pp.475-481
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• 2002

먹는샘물과 용기 중에 phthalate 및 adipate를 분석하였다. 시료 전처리법으로서 먹는샘물의 경우는 methylene chloride를 용매로 하여 액체-액체 추출법을 사용하였고, 고체 시료는 속 슬렛 추출과 실리카겔 정제법을 사용하였다. 추출 후 농축한 다음 GC-MS (SIM)로 정량하였다. 추출물의 chromatogram은 방해물질이 없고 각 피크는 분리가 잘 되었다. 물 시료의 경우 $0.1{\sim}10{\mu}g/L$의 농도범위에서 $r^2$값이 0.996 이상의, 용기시료의 경우 $1{\sim}1,000{\mu}g/Kg$의 농도범위에서 $r^2$값이 0.994이상의 좋은 직선성을 보였다. 물 시료 중에서 검출한계는 $0.002{\sim}0.010{\mu}g/L$의 범위를 용기 시료 중에서는 $0.01{\sim}0.02{\mu}g/Kg$의 범위를 보였다. 먹는샘물 5 종류, PET병 2 종류, 라벨 2 종류, 병뚜껑 2 종류 그리고 접착제 2 종류를 위의 방법에 따라 분석하였다. 그 결과 국내산 먹는샘물 중에서는 대부분 불검출 되었고 외국산 먹는샘물에서 총 프탈레이트 $1.2{\mu}g/L$의 농도가 검출되어 외국의 경우 긴 유통기간 때문에 높은 것으로 판단되나 인체에 유해한 정도의 농도는 아니었다. 용기 재질 분석에서도 국내산 PET 용기에서 (약 0.55 mg/Kg) 보다 외국산의 경우가 (약 1.2 mg/Kg) 비교적 높은 농도로 검출되었다. 한편 라벨이나 접착제에서는 비교적 높은 농도로 프탈레이트가 함유되어 있는 것으로 나타났다. 본 연구결과 먹는샘물과 용기 중에서 프탈레이트의 분석은 공시료 분석값을 정확히 빼주는 것이 필요하며 PET 시료채취 시에는 라벨과 본드를 제외시켜야 정확한 분석값을 구할 수 있는 것으로 나타났다.

• Korean Journal of Mathematics
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• 제18권2호
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• pp.195-200
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• 2010

Let C be a closed convex set in ${\mathbb{S}}^m$ or ${\mathbb{H}}^m$. Assume that ${\Sigma}$ is an n-dimensional compact minimal submanifold outside C such that ${\Sigma}$ is orthogonal to ${\partial}C$ along ${\partial}{\Sigma}{\cap}{\partial}C$ and ${\partial}{\Sigma}$ lies on a geodesic sphere centered at a fixed point $p{\in}{\partial}{\Sigma}{\cap}{\partial}C$ and that r is the distance in ${\mathbb{S}}^m$ or ${\mathbb{H}}^m$ from p. We make use of a modified volume $M_p({\Sigma})$ of ${\Sigma}$ and obtain a sharp relative isoperimetric inequality $$\frac{1}{2}n^n{\omega}_nM_p({\Sigma})^{n-1}{\leq}Vol({\partial}{\Sigma}{\sim}{\partial}C)^n$$, where ${\omega}_n$ is the volume of a unit ball in ${\mathbb{R}}^n$ Equality holds if and only if ${\Sigma}$ is a totally geodesic half ball centered at p.

• 한국발생생물학회지:발생과생식
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• 제10권1호
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• pp.9-17
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• 2006

제주땃쥐(Crocidura dsinezumi)의 세정관 상피 주기와 정자세포의 형태적인 특징을 알아보기 위하여 조사하였다. 제주땃쥐의 세정관 상피 주기는 12 stages로 구분되어졌다. Ad형 정원세포는 모든 단계에서 관찰되어졌으며, In형 정원세포는 IV단계에서, B형 정원세포는 V단계와 VI단계에서 관찰되었다. 정자세포의 첨체 발달과 핵의 형태적 변화는 14 steps로 구분되어졌다. 골지, 두모, 첨체, 성숙 및 이탈단계는 각각 $1{\sim}2,\;3{\sim}6,\;7{\sim}10,\;11{\sim}14$ 및 14 step으로 구분되어 나타났다. 이러한 우리의 결과들은 제주땃쥐의 정자 변태 과정에 대한 금후의 연구에 대한 기초를 제공해준다.

• 대한약리학회지
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• 제30권2호
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• pp.181-190
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• 1994

In rat atrium the characteristics of purinergic receptors were investigated by observing the effects of some purinergic receptor agonists and antagonists on action potential and contractile force. The statistically significant effects of $ATP(10^{-6}{\sim}10^{-3}M)$ and adenosine $(10^{-6}{\sim}10^{-3}M)$ on normal action potential characteristics were a dose-dependent shortening of action potential duration $(APD_{90})$ by both agents and hyperpolarization by $ATP(10^{-4},10^{-3}M)$. $CAP(10^{-8}{\sim}10^{-4}M)$, an $A_1$ adenosine receptor agonist, shortened $(APD_{90})$ markedly in a dose-dependent manner and these effects were almost abolished by $DPCPX\;(10^{-6}\;M), an $A_1$, adenosine receptor antagonist, but not affected by $DMPX(2{\times}10^{-6}\;M)$, an $A_2$ adenosine receptor agonist. On the other hand, CGS $21680(10^{-7}{\sim}10^{-4}M)$, an $A_2$ adenosine receptor agonist, elicited a slight shortening of $(APD_{90})$ and these effects were inhibited by DPCPX but persisted in the presence of DPMX. Adenosine $(10^{-6}{\sim}10{\-4}\;M)$ decreased the basal contraction of atrial muscle in a dose-dependent manner and these effects were not inhibited by DMPX but by DPCPX. These results suggests that purinergic receptor agonists depress the cardiac activity by a short ening of action potential duration and this effect is mostly mediated by $A_1$ adenosine receptors in rat atrium.

• International Journal of Concrete Structures and Materials
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• 제2권1호
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• pp.15-19
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• 2008

The most typical capping method for concrete structures is a sulfur-mortar compound capping, provided it satisfied the standard criterion set forth by ASTM C 617, but this conventional bonded-type method has many problems. It exhibits relatively the smaller unreliable value of the strength of high-strength concrete due to the differences of elasticity and strength between the cylinder and the cap, and manifests poor serviceability such as dangerous working tasks or a waste of the working time. To prevent these problems, unbonded-type capping methods have taken the place of the conventional methods in recent years. One of the popular methods is the use of synthetic rubber like a neoprene pad. Serious problems still remain in this method, which include the consideration of its chemical characteristics in consideration of the selection, the safekeeping and the economy of the pads. Moreover, the synthetic rubber pads cannot be used in concrete cylinder with strength greater than 80 MPa according to ASTM C 1231-00. New 'sand-capping method' presented in this study, can be applicable to the compressive strength evaluation of the high strength concrete in the range of $70{\sim}100\;MPa$. This new method has better simplicity and reliability than those of existing 'sand-box', because usual materials such as standard sand and simply-devised apparatus are used for the capping system. The statistical analysis of the test results revealed that the new sand-capping method exhibited the smallest deviation and dispersion, attesting for its much better reliability than other methods specified in ASTM C 1231/1231M.

• 센서학회지
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• 제29권5호
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• pp.354-359
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• 2020

The high vacuum hermetic sealing technique ensures excellent performance of MEMS resonators. For the high vacuum hermetic sealing, the customization of anodic bonding equipment was conducted for the glass/Si/glass triple-stack anodic bonding process. Figure 1 presents the schematic of the MEMS resonator with triple-stack high-vacuum anodic bonding. The anodic bonding process for vacuum sealing was performed with the chamber pressure lower than 5 × 10^-6 mbar, the piston pressure of 5 kN, and the applied voltage was 1 kV. The process temperature during anodic bonding was 400 ℃. To maintain the vacuum condition of the glass cavity, a getter material, such as a titanium thin film, was deposited. The getter materials was active at the 400 ℃ during the anodic bonding process. To read out the electrical signals from the Si resonator, a vertical feed-through was applied by using through glass via (TGV) which is formed by sandblasting technique of cap glass wafer. The aluminum electrodes was conformally deposited on the via-hole structure of cap glass. The TGV process provides reliable electrical interconnection between Si resonator and aluminum electrodes on the cap glass without leakage or electrical disconnection through the TGV. The fabricated MEMS resonator with proposed vacuum packaging using three-layer anodic bonding process has resonance frequency and quality factor of about 16 kHz and more than 40,000, respectively.

• Journal of electromagnetic engineering and science
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• 제7권4호
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• pp.175-182
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• 2007

In this paper, a study on the reflector type frequency doubler, to suppress the undesired harmonics, is presented. A 12 to 24 GHz reflective frequency doubler is simulated and experimented. Design procedure of the frequency doubler with reflector is provided and the frequency doubler with good spectral purity is fabricated successfully. It has harmonic suppression of the $40{\sim}50\;dBc$ in the $1^{st}$ harmonic and the $50{\sim}60\;dB$ in the $3^{rd}$ harmonic with no additional filter. And, it has conversion gain with the input power of 0 dBm over bandwidth of 500 MHz. A NEC's ne71300(N) GaAs FET is used and the nonlinear model(EEFET3) using IC-CAP program is extracted for harmonic load pull simulation. Good agreement between simulated and measured results has been achieved.

• 마이크로전자및패키징학회지
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• 제15권3호
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• pp.9-17
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• 2008

전기도금법으로 Cu 머쉬룸 범프를 형성하고 Sn 기판 패드에 플립칩 본딩하여 Cu 머쉬룸 범프 접속부를 형성하였으며, 이의 접속저항을 Sn planar 범프 접속부와 비교하였다. $19.1\sim95.2$ MPa 범위의 본딩응력으로 형성한 Cu머쉬룸 범프 접속부는 $15m\Omega$/bump의 평균 접속저항을 나타내었다. Cu머쉬룸 범프 접속부는 Sn planar범프 접속부에 비해 더 우수한 접속저항 특성을 나타내었다. 캡 표면에 $1{\sim}w4{\mu}m$ 두께의 Sn 코팅층을 전기도금한 Cu 머쉬룸 범프 접속부의 접속저항은 Sn 코팅층의 두께에 무관하였으나 캡 표면의 Sn코팅층을 리플로우 처리한 Cu머쉬룸 범프 접속부에서는 접속저항이 Sn 코팅층의 두께와 리플로우 시간에 크게 의존하였다.

• 콘크리트학회논문집
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• 제19권5호
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• pp.595-602
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• 2007

최근 CFRP (탄소섬유보강폴리머) 보강재를 이용한 콘크리트 구조물 보강이 교량 및 건축물 등에 널리 사용되고 있다. 본 연구에서는 교각 두부 보강에 프리스트레스가 도입된 표면매립 CFRP를 적용하였다. 적용된 공법의 효율성을 검증하기 위해 7개의 실험체를 제작하였으며, 기준 실험체, 외부 강선 보강 실험체, 탄소판 보강 실험체, 탄소 바 보강 실험체로 구성되어 있다. 보강재의 종류, 프리스트레스력의 크기를 실험 변수로 두어 실험을 하였으며, 실험 결과 프리스트레스가 도입된 표면매립 CFRP 보강 실험체의 극한강도가 기준 실험체에 비해 약 $20{\sim}33%$ 증가하는 것으로 나타났다. 또한 동일한 프리스트레스 도입량을 갖는 프리스트레스가 도입된 표면매립 CFRP 보강 실험체와 외부강선보강 실험체는 극한하중이 유사한 것으로 나타났다.