• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.566-569
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• 2008

Recently, the biolistic process is emerging as an effective needle-free drug delivery technique to transfer adequate concentrations of pharmacologic agents to soft living tissues with minimum side effects. We have started developing an effective method for delivering drug coated particles using laser ablation. A thin metal foil with deposited micro-particles on one side is irradiated with laser beam on the opposite side so that a shock wave is generated. This shock wave travels through the foil and is reflected, which causes and instantaneous deformation of the foil. Due to such a sudden deformation, the micro-particles are ejected at a very high speed. Here we present the experimental results of direct and confined laser ablation, which correspond to the initial stage of the whole experiment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1806-1809
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• 2008

Study that form micro pattern by direct ink jet printing method is getting attention recently. Direct ink jet printing spout fine droplet including nano metal particle by force or air pressure. There is reason which ink jet printing method is profitable especially in a various micro-patterning technology. It can embody patterns directly without complex process such as mask manufacture or screen-printing for existent lithography. In this study, research of a technology that ejects fine droplet form of Pico liter and forms metal micro pattern was carried with inkjet head of piezoelectricity drive system. Droplet established pattern while ejecting consecutively and move on the surface at the fixed speed. Patterns formed in ink are mixed with organic solvent and polymer that act as binder. So added thermal hardening process after evaporate organic solvent at isothermal after printing. I executed high frequency special quality estimation of CPW transmission line to confirm electrical property of manufactured circuit board. We tried a large area printing to confirm application possibility of an ink jet technology.

• 폴리머
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• 제31권4호
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• pp.322-328
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• 2007

촉매인 potassium(K)을 2회 분할 투입하는 음이온 개환중합반응으로 ${\varepsilon}-caprolactam$을 분산매인 liquid paraffin 내에서 분간 중합하여 $4{\sim}7\;{\mu}m$의 직경을 가지는 단분산된 구형의 polyamide 6 (Nylon 6) micro-particle를 제조하였다. 융착 방지제의 농도, 촉매의 양, 개시제의 양에 따라 생성된 입자 크기, 형태, 그리고 분포의 변화를 비교 분석하였다. 그 결과 개시제인 $PCl_3$의 양이 단량체의 $0.97{\sim}1.17\;wt%$일 때 약 90.6%의 수율을 얻었으며, 또한 촉매를 $1.3{\sim}1.4\;wt%$ 정도로 투입하였을 경우 가장 안정된 구형의 미세입자가 제조되고 높은 수율이 얻어짐을 알 수 있었다.

• 대한기계학회논문집B
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• 제24권6호
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• pp.753-759
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• 2000

Photoelectric charging is a very efficient way of charging small particles. This method can be applied to combustion measurement, electrostatic precipitator, metal separation and control of micro-contamination. To understand the photoelectric charging mechanism, particle charging of silver by exposure to ultraviolet is investigated in this study. Average charges and charge distributions are measured at various conditions, using two differential mobility analyzers, a condensation nucleus counter, and an aerosol electrometer. The silver particles are generated in a spark discharge aerosol generator. After that process, the generated particles are charged in the photoelectric charger using low-pressure mercury lamp that emits ultraviolet having wavelength 253.7 nm. The results show that ultra-fine particles are highly charged by the photoelectric charging. The average charges linearly increase with increasing particle size and the charge distribution change with particle size. These results are discussed by comparison with previous experiments and proposed equations. It is assumed that the coefficient of electron emission probability is affected by initial charge. The results also show that the charge distribution of a particle is dependent on initial charge. Single changed particle, uncharged particle and neutralized particle are compared. The differences of charge distribution in each case increase with increasing particle size.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.37-40
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• 2003

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing (CMP) process was required for the global planarization of inter-metal dielectric (IMD) layer with free-defect. However, as the IMD layer gets thinner, micro-scratches are becoming as major defects. Micro-scratches are generated by agglomerated slurry, solidified and attached slurry in pipe line of slurry supply system. It is well known that the presence of hard and larger size particles in the CMP slurries increases the defect density and surface roughness of the polished wafers. In this paper, we have studied aging effect the of CMP slurry as a function of particle size. We prepared and compared the self-developed silica slurry by adding of abrasives before and after annealing. As our preliminary experiment results, we could be obtained the relatively stable slurry characteristics comparable to original silica slurry in the slurry aging effect.

• 대한기계학회논문집A
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• 제35권9호
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• pp.1035-1040
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• 2011

본 논문은 세라믹과 금속파우더를 이용한 복합소재를 플라즈마 용사 방식으로 개발한 결과를 수록하였다. 사용된 세라믹 파우더는 $Al_2O_3+40TiO_2$ 이고 입자 크기는 $20{\mu}m$, $Al_2O_398+$파우더의 입자 크기는 $45{\mu}m$를 사용하였다. $20{\mu}m$, $30{\mu}m$ 및 $50{\mu}m$ 금속필터 입자는 SIKA-R 20IS, 30IS 및 50IS(소결금속필터)을 사용 했으며, $75{\mu}m$ 금속필터 입자는 5 겹 소결메쉬 필터를 사용��다. 용사 공정으로 가공된 복합 필터는 세라믹 파우더의 종류, 크기 및 코팅 두께에 따라 성능의 차이를 보였으나, 전반적으로 필터링 가능 능력은 향상되었다.

• Composites Research
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• 제21권6호
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• pp.15-22
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• 2008

본 연구는 SiC입자를 20% 강화된 알루미늄기 복합재료를 이용해서 평면굽힘피로시험을 향했다. 표면미소피로균열의 발생 및 진전거동은 레프리카법으로 연속관찰을 했고 파괴원인과 파괴기구를 규명하기 위해서 주사전자현미경을 이용했다. da/dn-$K_{max}$ 관계에서 저응력 레벨에서는 여러 개의 균열이 진전하고, 합체 등이 일어나는 것으로부터 진전속도는 꽤 분산(흐트러짐)이 심하고, 고응력 레벨에서는 비교적 흐트러짐은 적게 나타나는 것을 알 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 반도체재료
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• pp.30-33
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• 2001

Chemical mechanical polishing(CMP) process has been widely used to planarize dielectrics, which can apply to employed in integrated circuits for sub-micron technology. Despite the increased use of CMP process, it is difficult to accomplish the global planarization of free-defects in inter-level dielectrics (ILD). Especially, defects like micro-scratch lead to severe circuit failure, and affects yield. CMP slurries can contain particles exceeding $1{\mu}m$ size, which could cause micro-scratch on the wafer surface. The large particles in these slurries may be caused by particle agglomeration in slurry supply line. To reduce these defects, slurry filtration method has been recommended in oxide CMP. In this work, we have studied the effects of filtration and the defect trend as a function of polished wafer count using various filters in inter-metal dielectric(IMD)-CMP. The filter installation in CMP polisher could reduce defect after IMD-CMP. As a result of micro-scratches formation, it shows that slurry filter plays an important role in determining consumable pad lifetime.

• 대한화장품학회지
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• 제22권2호
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• pp.52-69
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• 1996

Nano-Sized TiO$_2$ particles with diameter between 2 and 5 nm are synthesized in Water/Triton X-100/n-Hexane microemulsion. Particles show the amorphous structure and partially hydroxide form. The optical absorbance of particles appears at 250nm and band edge at 340nm. Gold metal is deposited on the surface of TiO$_2$ particles by reduction reaction of Au(III) ion with sodium hypophosphite. The size of gold-deposited particles is 20nm, and the optical absorbance appears at 270nm and at 550nm. So particles show the red color. The dense precipitation is formed by aggregation in the TiO$_2$ nano-sized particles of about 5nm size. But the bulky precipitation is formed by agglomeration phenomena in the gold-deposited particles of 20nm size. And also gold-deposited particles is easily dispersed by being re-dispersed in PEG/Water solution. This study has compared those things measuring the SPF characteristics of the cosmetics made of the synthesized particles. If the particle size is controlled appropriately, then the SPF value will be higher, or more colorless cosmetics will be made.

• 한국결정성장학회지
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• 제24권3호
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• pp.94-98
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• 2014

$LiCoO_2$는 박막 베터리의 양극재료로써 많은 관심을 받고 있다. 본 연구에서는 스핀 코터를 이용한 졸-겔 합성공정과 열처리 과정에 의해서 Au 지지체 위에 $LiCoO_2$ 박막을 합성하였다. 합성된 박막의 구조는 X-선회절분석, 라만분광 광도계를 이용하여 분석하였다. 박막의 입자 형태는 전자현미경에 의해 관찰하였다. X-선회절분석, 라만분광광도계의 결과로부터, $550^{\circ}C$와 $750^{\circ}C$에서 합성된 박막은 스피넬구조와 층상 암염 형 구조를 가지는 박막으로 보이며, $650^{\circ}C$에서 합성된 박막은 층상 암염 형 구조와 스피넬 구조가 혼재되어져 있는 것으로 생각된다. $750^{\circ}C$에서 합성된 박막은 다른 낮은 온도에서 합성된 박막보다 큰 결정질의 균일한 분포의 입자를 가지는 것으로 확인되었다.