Earticle

시체의 피부에 유류된 용의자의 지문을 현출하는 것은 수사관의 능력이며 이렇게 현출된 지문은 사건해결에 중요한 증거자료가 될 수 있다. 국내에서는 피부에 유류된 잠재지문에 대한 연구가 활발히 이루어지지 않고 있고 특히 실제 시체를 이용하여 지문현출실험을 할 수 있는 여건이 성숙되어 있지 않다. 이에 본 연구에서는 사람의 피부와 해부 생리학적으로 가장 유사한 돼지피부를 이용하여 피부에 유류된 잠재지문 현출법을 적용해보았다. 분말법(Powder method)과 전사법(Transfer method), 시약법(Reagent method)으로 구분하여 적용하였으며, 적용환경은 환경부와 국립환경과학원에서 권장하는 실내 환경 매뉴얼의 조건에 따라 실험하였다. 분말법의 경우 magnetic powder에 비하여 흑색(형광)분말의 입자가 수분에 영향을 덜 받았으나, 선명도에 있어서 흑색(형광)분말은 magnetic powder보다 가시성이 떨어졌다. 또한 black magnetic powder보다는 fluorescent magnetic powder의 선명도가 보다 뛰어남을 확인할 수 있었다. 전사법은 분말과 Ruthenium tetroxide(이하 RTX)를 이용하여 kromekote, glossy paper, 금전등록기용 감열지(이하 thermal paper), slide glass에 적용하였으며, 분말의 적용에 있어서는 kromekote와 thermal paper가, RTX의 적용에 있어서는 kromekote에서 보다 나은 융선이 관찰되었다. 시약법은 Cyano acrylate(이하 CA)와 RTX, Sudan black을 적용하였으며, CA 적용 시에는 자연증발법이 Fuming gun(CYANOWAND)보다 좋은 결과를 나타내주었다. RTX는 적용 후 UV조사를 통해 최대 72시간까지 융선 관찰의 가능성을 보여주었으며, Sudan black의 경우 융선 관찰은 이루어지나 그 식별력은 떨어지는 것으로 나타났다. 본 연구결과가 향후 사건현장에서 시체에 대한 지문현출을 활성화하여 사건해결의 효율성을 높이는데 기여하길 바란다.

Recovering latent fingerprints from skin could be an important evidence for solving criminal cases. In Korean contexts, it is almost impossible to test detecting methods using the dead body. As an alternative, this study took advantage of pig skin to perform powder method, transfer method, and reagent method that is known for having the most similar characteristics to human skin. The results of powder method showed that, compared to magnetic powder, powder was less influenced by moisture but its definition was less visible. Also, it was found that fluorescent magnetic powder showed stronger visibility than black magnetic powder. The transfer method resulted in that, in applying powder, kromekote and thermal paper discovered better ridge. In applying RTX, better ridge was found in kromekote. The results of reagent method was that, in applying CA, natural evaporation showed a better result than fuming gun. Applying RTX suggested that ridge can be detected for up to 72 hours with the help of UV. Sudan black was also useful in detecting ridge but with poor visibility.

In this study, the effects of the compaction method for (Mg+2B) powders on the apparent density and superconducting properties of MgB2 bulk superconductor were investigated. The raw powders used in this study were nano-sized boron (B) and spherical magnesium (Mg). A batch of a powder mixture of (Mg+2B) was put in a steel mold and uniaxially pressed at 1 ton or 3 tons into pellets. Another batch of the powder mixture was uniaxially pressed at 1 ton and then pressed isostatically at 1800 kg/cm2 in the water chamber. All pellets were heat-treated at 650℃ for 1 h in flowing argon gas for the formation of MgB2. The apparent density of powder compacts pressed at 3 ton was higher than that at 1 ton. The cold isostatic pressing (CIP) in a water chamber allowed further increase of the apparent density of powder compacts, which influenced the pellet density of the final products (MgB2). The compaction methods (uniaxial pressing and CIP) did not affect the formation of MgB2 and superconducting critical temperature (Tc) of MgB2, but affected the critical current density (Jc) of MgB2 significantly. The sample with the high apparent density showed high Jc at 5 K and 20 K at applied magnetic fields (0-5 T).

The mechanical, electrical and thermal characteristics of insulating materials may significantly affect the performance and reliability of electrical devices using superconductors. General method to provide insulating layer between coated conductors is wrapping coated conductor with Kapton tape. But uniform and compact wrapping without failure or delamination in whole coverage for long length conductor is not a simple task and need careful control. Coating of insulating layer directly on coated conductor is desirable for providing compact insulating layer rather than wrapping insulating layers around conductor. Ceramic added polymer has been widely used as an insulating material for electric machine because of its good electrical insulating properties as well as excellent heat resistance and fairy good mechanical properties. The insulating layer of coated conductor should have high breakdown voltage and possesses suitable mechanical strength and maintain adhesiveness at the cryogenic temperature where it is used and withstand stress from thermal cycling. The insulating and mechanical properties of polymer can be improved by adding functional filler. In this study, insulating layer has been made by adding ceramic particles such as SiO2 to a polymer resin. The size, amount and morphology of added ceramic powder was controlled and their effect on dielectric property of the final composite was measured and discussed for optimum composite fabrication.

연구에서는 ‘도( )’라는 철학이념을 핵심으로 중국화 창작의 본색을 탐색하고‘음(陰)’과‘양 (陽)’,‘허(虛)와‘실(實)’,‘강(剛)’과‘연(柔)’,‘유중생무(有中生無)’,‘무중생유(無中生有)’의 변증적 기법 을 활용하여 중국화 창작의‘묘용의도(妙用之道)’를 탐색하는 것을 목적으로 저서, 학술지, 학술논문, 및 웹사이 트에 공개되는 학술포럼 등 이론적 선행연구를 바탕으로‘몰골화(沒骨畵)’의 기법 중 하나인, ‘당수당분법’의 개념과 발전과정에 관한 탐색적 연구를 실시함과 동시에‘몰골화(沒骨畵)’의 유명 화가들의 대표작품을 분석하 여 대표 화가들이 사용하는 기법이 표현하는 미학적 이념과 철학적 관념을 탐구하며, 현대 미술 창작에 미치는 영향을 고찰하였다. 이를 통해 중국전통회화 기법 중의 당수당분법’(撞水撞粉法)과 ‘물타기법’(积水法)의 응용 과 중국전통회화 기법에서 형성된 특유의 화면 효과를 통한 주관적 표현기법이 현재 중국의 회화 및 화면 공간 표현에 미치는 영향을 고찰하였다.

This research takes the philosophical concept of ‘Dao’ as the core to explore the true color of Chinese painting creation, and aims to explore the ‘magic way’ of Chinese painting creation by using the dialectical techniques of ‘yin’, ‘yang’, ‘virtual’, ‘real’, ‘rigid’, ‘soft’, ‘create something from nothing’, ‘create nothing from something’. On the basis of theoretical advance research in academic journals, academic papers, and academic forums published on the website, while conducting exploratory research on the painting method of ‘mogu painting’concept and development process of ‘Hit the water or hit the powder method’, this paper analyzes the representative works of famous painters of ‘mogu painting’, discusses the aesthetic and philosophical concepts the techniques used by the representative painters, and examines the impact on modern art creation. Through this, this reserch verified The effect of Chinese painting and screen space expression through the subjective expression technique of unique screen effect formed in traditional Chinese painting techniques and apprication of‘hit the water or hit the powder method’ and ‘Water Accumulation Method’.

국내 은 함유 폐자원의 고부가가치 제품화를 위한 연구의 일환으로써 sodium formaldehydesulfoxylate와 ascorbic acid를 각각 환원제로 사용한 Ag 나노분말의 제조실험을 수행하였다. Ag 수용액은 질산은을 소정 농도로 증류수에 용해시켜 사용하였으며, Ag 미립자의 응집방지를 위한 분산제로는 Tamol NN8906, PVP, SDS 및 caprylic acid를 각각 사용하였다. 환원반응을 통하여 제조한 Ag 미립자는 입도분석기 및 TEM 측정을 통하여 morphology 와 평균입도를 측정하였다. sodium formaldehydesulfoxylate에 의한 은의 환원을 위해서는 이론치의 1.4배를 첨가해 주어야 하는 것으로 나타났으며, ascorbic acid와는 달리 생성된 Ag 입자가 너무 크게 성장하는 문제점이 있었다. 분산제에 따른 Ag 입자의 특성을 살펴본 결과, Tamol 및 PVP를 사용한 경우에는 bimodal distribution을 보였으나, SDS 와 caprylic acid의 경우에는 수십 nm에서 100 m에 이르는 매우 broad한 입도분포를 보였다.

As one of the hydrometallurgical processes available in the recycling of silver-bearing wastes, the preparation of Ag nano-powder was investigated by a reductive precipitation reaction in silver solution using sodium formaldehydesulfoxylate and ascor-bic acid as a reducing agent. Silver solution was prepared by dissolving silver nitrate with distilled water, and Tamol NN8906,PVP, SDS and caprylic acid were also used respectively as the dispersant to avoid the agglomeration of particles during theesize analyzer and TEM to determine the particle size distribution and morphology. It was found that about 40% excess of sodiumformaldehydesulfoxylate was required to reduce completely silver ions in the solution. It also appeared that the particle size gen-erated with sodium formaldehydesulfoxylate was much greater than that with ascorbic acid. As far as the efect of dispersanton the Ag particles was concerned, the particle size distribution showed typically bimodal distribution in case of Tamol/PVPwhile very broad distribution ranged from 0.01 to 100m appeared in case of SDS/caprylic acid.

WPCB에 포함된 주요금속(Cu, Fe), 귀금속(Au, Ag)뿐만 아니라 미량의 금속성분을 회수하고 유해금속의 처리효율을 증가시키기 위한 연구로, 본 연구그룹에서는 기계적 연삭법을 이용해 전기전자부품을 탈거시키는 연구를 발표하였다. 폐PCB는 연삭처리를 통해, 부품이 탈거된 기판(dismantled PCB), 탈거된 전기전자부품(electric/electronic components, EECs) 그리고 연삭분진(abrasion powder)으로 회수되었다. 본 연구에서는 금속성분이 29.8wt% 함유된 연삭분진으로부터 금속성분을 분리하기 위해 역비중침강법(Elutriation method, reverse of gravity sedimentation)을 이용하였다. +100 mesh 분진의 경우, 액상매질 상승속도 7 mm/s, 튜브높이 100 mm 에서 금속품위 91.5%, 회수율 97.5%로 회수가 가능하였고, 반면에 ‒200 mesh구간 분진의 경우는 액상매질 상승 속도 및 튜브의 높이 변화에 따른 금속성분의 품위 및 회수율의 차이가 거의 나타나지 않았으며 액상매질 상승속도 1 mm/s, 튜브 높이 100 mm조건에서 35.7%의 금속품위 및 28.9%의 회수율을 나타내었다. 이는 연삭분진의 입자크기가 작아짐에 따라 금속/비금속성분 입자간 종말 침강속도의 차이가 감소되어 액상매질과 동시에 동반 부유된 결과로 판단된다.

In previous research, our research group has studied about disassembly of electric/electronic components from wasted printed circuit boards (WPCBs) by using surface grinding method. During this procedure, 13.9 wt% of WPCBs was occurred to abrasion powders, which contained a mess of metals about 29.8 wt%. As a subsequent research, the authors have tested for elutriation method (reverse of gravity sedimentation) to separation of metal phase components from the abrasion powder. As for the range of +100 mesh size in abrasion powder, 97.5 wt% of metals could be recovered at a 7 mm/s of upward-velocity in liquid-phase medium, the tube height of 100 mm. whereas, in the case of +100 mesh size in powder, metal recovery decreases with a decrease of powder sizes. And also, in the case of ?200 mesh, the recovery was 28.9% at a velocity of 1 mm/s, the tube height of 100 mm. This implies the settling velocity and its gap between metal and non-metal components decrease in proportion to their sizes.

ABS sensor ring has been manufactured by powder metallurgy (P/M) method using 400 series ferrite stainless steel. The results are following. It is supposedly sufficient to use for control computer due to good experimental results of magnetic characteristics. Compared with sensor ring made by iron, 400 series ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. Thus the decreasing production process has been obtained. As a result mechanical characteristics of hardness and tensile test, 400 series ferrite stainless steel shown a good endurance when it is combined to constant velocity joint(C/V), and has a good hardness properties endurable to sand and pebble impact. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition.

과립 분말 야금법은 기존 분말 야금법보다 치밀도가 높은 소결 부품을 얻을 수 있는 제조 기술이다. 하지만 추가 과립화 공정에 따른 생산 비용 증가가 상당하다는 단점이 있다. 과립 분말 야금법의 생산성 향상을 위해서는 과립 분말 제조 시 높은 회수율이 보장되어야 한다. 본 논문에서는 분체 동역학 전산 해석법인 이산요소법을 이용하여 과립 분말의 수율에 영향을 미치는 과립화 공정의 특성에 대해 살펴보았다. 분무 과립 공정 중 과립화 분말의 비산, 충돌 및 소착 현상을 시뮬레이션함으로써 분무 건조기의 운전 조건에 따른 과립화 분말의 파손 및 회수 가능 여부를 예측하였다. 본 논문의 가상 공정 시뮬레이션 융합 연구 결과는 실제 금속 분말의 분무 과립화 공정의 생산성 향상에 이바지할 것으로 기대한다.

A powder metallurgy process with granules is the manufacturing technology that can achieve higher-density sintered parts than conventional powder metallurgy processes. However, there is a disadvantage in that the production cost increases significantly due to the additional granulation step. High granule productivity must be guaranteed for affordable material costs in this manufacturing technology. This paper performed a series of scattering, collision, and adhesion simulations of agglomerated powders to investigate the characteristics of granulation process affecting the manufacturing yield rate. The results of this simulation-based convergence study can contribute to improving productivity in the metal powder spray granulation process.

전자종이를 구현하는 여러 가지 기술이 제안되어 연구되고 있으나 아직까지는 전자종이로서의 완전한 요구를 충족시키지 못하고 있다. 본 연구의 주요 목표는 종이 인쇄물과 기존의 디스플레이 매체를 대신할 수 있는 새로운 표시소자인 전자종이(e-paper)의 구동조건 및 계조 표현 방법을 개발하는 것이다. 이를 위해 상판 및 하판 분리 충전방식으로 제작된 액상분말 디스플레이 소자를 위한 구동회로 설게 및 셀단위 계조표현이 가능한다 채널 구동 장치를 개발하였으며, 연구내용을 바탕으로 액상분말 디스플레이 소자의 특성을 개선할 수 있는 방향을 제시하였다.

Many techniques to realize e-paper is proposed, but full requirement of e-paper is still not satisfied. In this paper, driven condition and gray scale representation method of e-paper is proposed. As a result of this study, multi-channel drive for allowing gray scale representation by cell is developed. And also drive circuit design for liquid powder display panel is developed.

Characteristics of good-quality red pepper powder produced using N2-circulated low-temperature drying method were compared with those made through conventional sun and hot-air drying methods. Kimchi and kochujang were prepared with different types of red pepper powder, and their physicochemical and sensory properties were compared. Results revealed Hunter L (lightness), a (redness), and b (yellowness) values of N2-circulated low temperature-dried red pepper were highest. Absorbance of crude capsanthin in hot air-dried red pepper powder (0.584±0.001) was significantly lower than sun-dried (0.848±0.001) and N2-circulated low temperature-dried products (0.832±0.002. Use of N2-circulated low-temperature drying method resulted in the highest amounts at reducing sugar and total vitamin C. Capsaicin content of N2-circulated low temperature-dried products were higher than hot air-dried ones. The aL values of kochujaug made with sun-and low temperature-dried red peppers were higher than that of kochujang made with hot-dried red peppers. Physicochemical and sensory evaluation results showed red pepper powders made using N2-circulated low-temperature drying method have the best quality among all samples tested.

As a traditional method to apply fingerprint powder, brush method ("dusting") can create a risk to the health of crime scene investigators due to the inhalation toxicity of harmful and fine powders. Therefore, as a new method of applying powders, we tried to evaluate the potential of a chamber method for the development of latent fingerprint using fans in a closed chamber with a fixed capacity that can prevent the powders from being blown outside and exposed to the users, by comparing with the development results of the conventional brush method. Fingerprints on glass and plastic (PET) were extracted with black powder and green fluorescent powder, and the sharpness and minutiae of the developed fingerprints were compared for each method. The results of the black powder showed similar results, but the effect of the chamber method was slightly decreased when the green fluorescent powder was used. In order to improve the development with the green fluorescent powder, the mixture (50 : 50) of the fluorescent powder with the silica gel was tested and the results were similar to those of the brush method. It is expected that the chamber method has a high potential as a new powder application method considering the health of the crime scene investigator after fine tuning of development conditions with additional studies.

Tin Oxide(SnO2) has been widely investigated as a transparent conducting oxide (TCO) and can be used in optoelectronic devices such as solar cell and flat-panel displays. It would be applicable to fabricating the wide bandgap semiconductor because of its bandgap of 3.6 eV. In addition, SnO2 is commonly used as gas sensors. To fabricate high quality epitaxial SnO2 thin films, a powder sputtering method was used, in contrast to typical sputtering technique with sintered target. Single crystalline sapphire(0001) substrates were used. The samples were prepared with varying the growth parameters such as gas environment and film thickness. Then, the samples were characterized by using X-ray diffraction, scanning electron microscopy, and atomic force microscopy measurements. We found that the strain evolution of the samples was highly affected by gas environment and growth rate, resulted in the delamination under O2 environment.

Tin Oxide (SnO2) has been widely investigated as a transparent conducting oxide (TCO) and can be used in optoelectronic devices such as solar cell and flat-panel displays. In addition, it would be applicable to fabricating the wide bandgap semiconductor because of its bandgap of 3.6 eV. There have been concentrated on the improvement of optical properties, such as conductivity and transparency, by doping Indium Oxide and Gallium Oxide. Recently, with development of fabrication techniques, high-qulaity SnO2 epitaxial thin films have been studied and received much attention to produce the electronic devices such as sensor and light-emitting diode. In this study, powder sputtering method was employed to deposit epitaxial thin films on sapphire (0001) substrates. A commercial SnO2 powder was sputtered. The samples were prepared with varying the growth parameters such as gas environment and film thickness. Then, the samples were characterized by using XRD, SEM, AFM, and Raman spectroscopy measurements. The details of physical properties of epitaxial SnO2 thin films will be presented.

Cermet is a combination of metal and ceramic, it exhibits some special properties, so it is one of the most widely usedengineering materials. In this paper, the properties of encapsulated SiO2/Al cermet were prepared by powder metallurgymethod. Results showed that the density of SiO2/Al cermet is increased with an increasing Al content. When the Al contentis high, and the high temperature is sintered, the liquid phase can fully bond the surrounding SiO2 particles to form a relativelycontinuous and dense structure, thereby obtaining a high microstructure density. When the SiO2:Al ratio is increased from 1:1to 1:3, the hardness is gradually increased. The hardness and density of the sample are gradually increased with an increasingmolding pressure. The surface hardness of the cermet is increased first and then decreased with an increasing sinteringtemperature. When the SiO2:Al ratio is 1:3, the holding time is 10 min under molding pressure of 15 MPa, and the sinteringtemperature is 900 °C for 1 h, the surface hardness of the obtained coated SiO2/Al cermet is high, the value is 175.2 HV.

Cermet materials are important new engineering materials with combined advantages of ceramics and metals. In this study,Al2O3/Al cermet materials were prepared through powder metallurgy. The effect of sintering technology on the properties ofAl2O3/Al cermet materials was analyzed as basis for preparing high-performance cermet materials. Results showed that whenthe sintering temperature was increased from 700 oC to 1000 oC under holding time for 1 h, the densification degree and hardnessof Al2O3/Al cermet materials decreased and the electric resistivity increased. In the microstructure of Al2O3/Al cermet materials,Al particles were larger and continuously distributed, whereas the Al2O3 particles were smaller and discontinuously distributed. When the holding time was increased under sintering temperature of 700 oC, the densification degree and hardness of Al2O3/Alcermet materials also increased, and the electric resistivity decreased. When 25 wt% Al2O3/Al cermet materials were sintered at700 oC for 3 h, the densification degree was higher, with hardness of 2203 HV and electric resistivity of 0.0159 Ω ? m.

For quality control of components in Korean red ginseng powder and extract, a new method for simultaneous quantification of 12 ginsenosides ($Rg_1$, Re, Rf, $Rh_1$, $Rg_2$[S], $Rg_2$[R], $Rb_1$, Rc, $Rb_2$, Rd, $Rg_3$[S], and $Rg_3$[R]) was studied. Compared to the official method for quantification of marker substances (ginsenosides $Rg_1$ and $Rb_1$), the proposed methods were guaranteed by in-house method validation. Several criteria such as linearity, specificity, precision and accuracy were evaluated. For red ginseng powder, recovery (averaging 95% to 105%) was calculated, and analysis of variance was carried out to estimate the relative standard deviation (0.20% to 2.12%). For red ginseng extract, the average recovery rate was 90% to 99% and the relative standard deviation was 0.39% to 2.40%. These results indicate that the proposed method could be used in the laboratory for determination of 12 ginsenosides in red ginseng powder and extract. In addition, this method was found to be suitable for quality control of ginseng products and potentially offer time and cost benefits.