• 대한약침학회지
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• 제4권1호
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• pp.65-84
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• 2001

We recently demonstrated that bee venom (BV) injection into acupoint (i.e. Zusanli) produced more potent anti-inflammatory and antinociciptive effect in Freunds adjuvant induced rheumatoid arthritis (RA) model as compared with that of non-acupoint injection(i.e back). However, the precise components underlying BV-induced antinociceptive and/or anti-inflammatory effects have not been fully understood. Therefore, we further investigated the anti-arthritic effect of BV after extracting the whole BV according to solubility (water soluble: BVA, ethylacetate soluble: BVE). Subcutaneous BVA treatment (0.9 mg/kg/day) into Zusanli acupoint was found to dramatically inhibit paw edema and radiological change (i.e. new bone proliferation and soft tissue swelling) caused by Freunds adjuvant injection. In addition, the increase of serum interleukin-6 by RA induction was normalized by the BVA treatment as similar with that of non-arthritic animals. On the other hand, BVA therapy significantly reduced arthritis induced nociceptive behaviors (i.e., nociceptive score for mechanical hyperalgesia and thermal hyperalgesia). Furthermore, BVA treatment significantly suppressed adjuvant induced Fos expression in the lumbar spinal cord at 3 weeks post-adjuvant injection. However, BVE treatment (0.05 mg/kg/day) has not any anti-inflammatory and anti-nociceptive effect on RA. Based on the present results, we demonstrated that BVA might be a effective fraction in whole BV for long-term treatment of RA-induced pain and inflammation. However, it is clear necessary that further fraction study about BVA was required for elucidating an effective component of BVA.

• 공업화학
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• 제31권5호
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• pp.545-551
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• 2020

인지질과 세라마이드 간 상호적 자가회합 특성을 활용하여 수화 액정형 베시클 제조를 시도하였다. 인지질과 세라마이드의 혼합지질에 에지 액티베이터를 첨가하면 난용성의 세라마이드를 고 함량으로 함유하는 베시클 제조가 가능하였다. 본 연구에서는 인지질, 세라마이드, 에지 액티베이터의 혼합 조성에 따른 수화 액정상의 구조적, 열적 특성 등의 변화를 관측하고, 혼합 조성을 달리하여 만든 베시클의 입자크기 및 베시클 분산액의 안정성을 비교하였다. 실험 결과, 인지질과 세라마이드 간 혼합에서 세라마이드 비율을 최대 70%까지 늘려서, 베시클 분산액 전체 대비 세라마이드를 3.5 wt% 함유되는 제형을 제조할 수 있었다.

• 한국전기전자재료학회논문지
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• 제25권8호
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• pp.602-610
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• 2012

The powders for the $Na_xWO_3$ (x= 1 and 0.75) sputtering targets were synthesized by the calcination in reductive atmosphere. Near single-phase $NaWO_3$ and single-phase $Na_{0.75}WO_3$ powder targets were prepared. By using the targets, thin films of each composition were deposited by rf magnetron sputtering on the $SiO_2$ (100 nm)/Si substrates and annealed by RTP (rapid thermal processing) for crystallization. In the case of the $NaWO_3$ composition, single-phase $Na_xWO_3$ thin films, where x was believed to be slightly less than 1, were fabricated accompanying the Na-diffusion into the substrates during RTP. However, in the case of the $Na_{0.75}WO_3$ thin film preparation, it was unable to make single-phase thin films. From the phase formation behaviors of both powders and thin films, it was revealed that $Na_xWO_3$ with nonstoichiometric composition of x, which was slightly less than 1, was favorable. The good electrical conduction properties were obtained from the single-phase $Na_xWO_3$ thin films. Their electrical resistivities were as low as $7.5{\times}10^{-4}{\Omega}{\cdot}cm$.

• 멤브레인
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• 제26권2호
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• pp.141-145
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• 2016

고분자전해질막은 전극 이외에 전기 화학 연료전지의 성능을 결정하는 중요한 요소이다. 고분자전해질막은 가스나 양성자 등의 작은 분자를 선택적으로 수송해야 한다. 고분자전해질막을 투과한 가스는 급속히 전기 화학적 환원을 발생시켜 음극 촉매의 열화를 유발하기 때문에 수소 장벽으로 작동해야 하며 가능한 한 빨리 양성자를 이동시켜야 한다. 지금까지 고분자전해질막의 수소 기체 투과도를 측정하는데 한정된 방법(예 : Constant volume/variable pressure (Time-lag)법)을 사용했다. 그러나 측정의 대부분은 고분자전해질막은 건조된 진공 하에서 이루어진다. 그렇지 않으면 얻어진 수소 투과도는 측정 오차가 커지는 원인이 되기 쉽다. 이 연구에서는 일반적으로 고분자전해질막으로 사용되는 Nafion212의 수소 가스 투과 특성을 온도와 습도가 동시에 제어되는 in-situ 측정 시스템을 이용하여 평가하였다.

• 대한치과기공학회지
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• 제21권1호
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• pp.5-14
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• 1999

Glass ceramics for dental crown prosthesis were prepared by crystallization of CaO-MgO-SiO2-$P_2O_5-TiO_2$ glasses. Their crystallization behaviors have been investigated as a function of heattreatment temperature, holding time and chemical composition in relation to mechinical properties. Crystallization peak temperatures were determined by differential thermal analysis(DTA). Crystalline phases and mircostructures of heat-treated sample were determined by the means of powder X-ray diffraction(XRD) and scanning electron microscopy(SEM). The final crystalline phase assemblages and the microstructures of the samples were found to be dependent on glass compositions, heattreatment temperature, and holding time. 1st crystallization peak temperature(TP), affected strongly by apatite, was found to be increased or decreased. From the experiment, the following results were obtained : 1. The crystallization peak temperature($T_P$) formed by apatite increased until adding up to 9wt% $TiO_2$ to base glass composition, then decreased above that. 2. Apatite($Ca_{10}P_6O_{25}$), whitlockite(${\beta}-3CaO-P_2O_5$), $\beta$-wollastonite($CaSiO_3$), magnesium tianate($MaTiO_3$) and diopside(CaO-MgO-$2SiO_2$) crystal phase were precipitated in MgO-CaO-$SiO_2-TiO_2-P_2O_5$ glass system containing 9wt% and 11wt% of $TiO_2$ 3. Vickers hardness of samples increased with increasing heat-treatment temperature and Vickers hardness of S415T9 samples heat-treated at 1075 was approxi-mately 813Kg $mm^{-2}$ as maximum value. 4. Vickers hardness of samples increased due to precipitation of apatite, whitlockite, $\beta$-wollastonite, magnesium titanate, and diopside crystal phases within glass matrix.

• 한국전기전자재료학회논문지
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• 제29권12호
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• pp.786-790
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• 2016

Hole explosion behaviors were observed during drilling fine holes with laser beam on the LTCC green bar of $320{\mu}m$ thick after lamination of green sheets prepared by tape casting of thick film process. The incidence of these hole explosions was inversely proportional to hole sizes. The incidence of hole explosion was 20 % number of hole with the size of $60{\mu}m$ exploded for the UV radiation, while the explosion did not appear for hole sizes over $100{\mu}m$. To prevent hole explosion behavior during laser-drilling of fine holes, carbon black powder was added as an additive in the LTCC composition, which has superior thermal durability. As a consequence, hole explosion rate was suppressed to 0.8 % for the hole size of $50{\mu}m$ green sheet with the carbon black amount of 10 weight % and the laser power of 3 watt. Added carbon is thought to reduce the heat-affected region during laser drilling.

• Composites Research
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• 제16권1호
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• pp.26-33
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• 2003

열-음향방출(thermo-acoustic emission)기법을 이용함으로써, 직교형 복합재료적층판의 저온냉각 시에 형성되는 미세손상을 검출하고 평가하여 그 유효성을 검토하였다. 액체질소에 의한 저온냉각($-191^{\circ}C$)으로 생성된 미세손상은 가열-냉각 열부하사이클 시에 발생하는 음향방출(AE)거동의 해석을 통해 평가되었다. 저온냉각에 따른 섬유파단과 모재파손은 초음파 C스캔, 광학현미경, 주사형 전자현미경을 통해 관찰되었으며, 이들 미세파손 모드는 AE신호의 퓨리에 변환(FFT)처리해석, 단시간 퓨리에 변환(STFT)처리해석으로 분류되는 3종류의 서로 다른 특징을 갖는 AE신호로 검출될 수 있었다. 이들 AE신호특성을 시간 단계별로 검출하여 저온냉각시에 형성되는 복합재료 미세파괴의 과정을 실시간으로 평가할 수 있었으며, 또한 열부하 사이클시의 AE신호해석을 통해서 저온 냉각으로 생성된 미세파손의 정도를 추정할 수 있었다.

• 한국자기학회지
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• 제18권1호
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• pp.32-35
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• 2008

차세대 반도체 산업의 발전을 위하여 반도체 소자의 구조는 DRAM, FRAM, MRAM 등 여러 분야에서 다양한 연구가 진행되고 있다. 특히 이런 차세대 반도체 소자에서 금속 배선으로는 Cu가 사용되며, Cu 금속 배선을 위한 확산방지막에 대한 연구는 반드시 필요하다[1-3]. Cu 금속 배선을 위한 확산방지막에 대한 현재까지의 연구에서는 Tungsten(W)을 기반으로 Nitride(N)를 불순물로 첨가한 확산방지막에 대하여 연구되었다[4-7]. 이러한 W-N를 기반으로 본 연구에서는 물리적 기상 증착법(PVD) 방법인 RF Magnetron Sputter 방법으로 W-N 이외에 Carbon(C) 과 Boron(B)을 첨가하여 확산방지막의 특성을 확인하였고, 특히 Boron Target의 power를 변화하여 W-B-C-N 확산방지막의 Boron에 의한 특성과 열적 안정성을 연구하였다[8-10]. 실험은 다양한 Boron의 조성을 가지는 확산방지막을 증착하여 $\beta$-ray와 4-point probe를 사용하여 확산방지막의 특성을 확인하였고, 고온($700^{\circ}C{\sim}1000^{\circ}C$) 열처리한 후 X-ray Diffraction 분석을 하여 열적 안정성을 확인하였다.

• Elastomers and Composites
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• 제53권3호
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• pp.158-167
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• 2018

In this study, in-situ trans-selective polymerization of isoprene was carried out using titanium-based Ziegler-Natta catalysts. The catalysts were prepared by high-energy ball milling. Individually Large-inner-diameter carbon nanotubes (CNTL), and hydroxylated carbon nanotubes (CNTOH), along with magnesium chloride ($MgCl_2$) were used as the carriers for the catalysts. The optimum ball-milling time for preparing the $CNT/MgCl_2/TiCl_4$ Ziegler-Natta catalysts was 4 h. The $CNTOH/MgCl_2/TiCl_4$ catalyst showed a higher efficiency than that of the $CNTL/MgCl_2/TiCl_4$ catalyst, based on the rate of polymerization. The effects of the CNT-filler type on the isoprene polymerization behaviors and polymer properties were investigated. The morphologies of the trans-1,4-polyisoprene (TPI)/CNT and TPI/CNTOH nanocomposites exhibited a tube-like shape, and the CNTL and CNTOH fillers were well dispersed in the TPI matrix. In addition, the thermal stability of TPI significantly increased upon the introduction of a small amount of both CNTL/CNTOH fillers (0.15 wt%), owing to the satisfactory dispersion of the CNTL/CNTOH in the TPI matrix.

• 반도체디스플레이기술학회지
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• 제10권1호
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• pp.43-49
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• 2011

In this study, the dynamic characteristics of an air spring connected with an external chamber through a flexible tube are examined. The uncoupled dynamic parameters of the air spring are identified through experiments, followed by the suggestion of a model-based approach to obtain the remaining coupled dynamic parameters using the various frequency response functions derived in PART I paper [1]. To improve or control the damping characteristics of the air spring, this vibration isolation air spring system is physically established in laboratory scale. And we attempt to identify various parameters used to describe to air spring system by both theoretically [1] and experimentally, which is performed in this report. The damping parameter of the tube system is identified through experiments on the system incorporated with the air cylinder, and a nonlinear regression procedure is employed to find solutions. The resulting value is used to expect the frequency response function of dynamic pressure in the top chamber (air spring) with respect to that in the bottom chamber (external chamber). Comparison with the experimental data supports the validity of the present estimation procedures. Also, the dynamic mechanism of the damping effects particularly in a low frequency range is investigated through this experimental endeavor.