• 대한화학회지
• /
• 제42권5호
• /
• pp.512-518
• /
• 1998

정적 광산란, 동적 광산란, 점성도 실험을 통해 수용액에서 안정한 콜로이드를 형성하는 폴리에틸렌계 아이오노머 입자의 질량평균분자량$(M_w)$, 관성회전반경$(R-g)$, 2차 비리얼계수$(A_2)$, 유체역학적 반경$(R-H)$, 크기 분포, 고유 점성도 등이 측정되었다. 측정값을 토대로 아이오노머 측기 조성에 따른 입자의 특성과 용액 거동을 조사하였다. 카르복시산염의 함량이 높은 아이오노머는 chain stiffness, $R-H$, $R-g$가 크고, 아마이드기 함량이 높은 아이오노머는 크기가 작고, 고분자 사슬이 조밀한 구조의 입자를 형성하였다. 또한 CMC 부근의 매우 묽은 농도 영역에서 확산계수와 점성도의 농도 의존성은 아마이드기가 도입된 아이오노머와 그렇지 않은 아이오노머에서 서로 상반되는 경향성을 보여, 수용액에서 형성된 아이오노머 입자간의 상호 작용이 아이오노머에 도입된 측기 조성에 따라 크게 달라짐을 알 수 있었다.

• 대한의용생체공학회:의공학회지
• /
• 제30권1호
• /
• pp.18-22
• /
• 2009

Laser has been widely used in various fields of medicine. Recently, noninvasive low-level laser therapeutic medical devices have been introduced in market. However, low-level laser cannot deliver enough photon density to expect positive therapeutic results in deep tissue layer due to the light scattering property in tissue. In order to overcome the limitation, this study was aimed to develop a negative pressure applied low-level laser probe to optimize laser transmission pattern and therefore, to improve photon density in soft tissue. In order to evaluate the possibility of clinical application of the developed laser probe, ex-vivo experiments were performed with porcine skin samples and laser transmissions were quantitatively measured as a function of tissue compression. The laser probe has an air suction hole to apply negative pressure to skin, a transparent plastic body to observe variations of tissue, and a small metallic optical fiber guide to support the optical fiber when negative pressure was applied. By applying negative pressure to the laser probe, the porcine skin under the metallic optical fiber guide is compressed down and, at the same time, low-level laser is emitted into the skin. Finally, the diffusion images of laser in the sample were acquired by a CCD camera and analyzed. Compared to the peak intensity without the compression, the peak intensity of laser increased about $2{\sim}2.5$ times and FWHM decreased about $1.67{\sim}2.85$ times. In addition, the laser peak intensity was positively and linearly increased as a function of compression. In conclusion, we verified that the developed low-level laser probe can control the photon density in tissue by applying compression, and therefore, its potential for clinical applications.

• 대한기계학회논문집
• /
• 제11권1호
• /
• pp.118-123
• /
• 1987

본 연구에서는 새로 고안된 연료주입기(air injector)바로 뒤에 입사압축파를 반사시키기 위한 벽을 설치하므로써 고체입자의 입사압축파에 대한 노출을 최대한 줄 였고 또한 새로운 연료주입기에 의해 매우 잘 분포된 입자분포를 얻을 수 있었다. 반사압축파에 의해 생성된 고온 고압의 산소중에서의 고체입자의 점화지연시간을 측정 하므로써 기체유동이 존재하는 입사압축파실험에서의 점화지연시간과 비교하여 기체유 동이 고체 미립자의 점화에 미치는 영향을 알아볼 수 있었고 반사압축파에 의한 점화 상태 조건하에서도 표면 점화모델이 성립하는지를 고찰해 보았다.

• 한국언론정보학보
• /
• 제35권
• /
• pp.181-210
• /
• 2006

본 연구는 식품 안전을 둘러싼 위험 상황을 보도하는 언론의 보도 프레임을 추출, 언론이 위험 상황을 위기의 사회 현실로 구축해가는 양상을 분석하는 것을 목적으로 한다. 이를 위해 1989년 삼양라면 우지파동에서 2005년 김치 기생충 알 검출 사건에 이르는 11개 식품안전 사고를 보도한 언론보도 내용을 대상으로 미디어 프레임을 분석, 각 프레임을 이루는 장치를 통해 언론이 위기를 구축해가는 양상을 추적했다. 분석에 사용된 프레임은 책임소재, 갈등, 인간적측면의 부각, 경제적 결과, 도덕성 등 다섯 가지 프레임이었으며, 연구 결과 이들 프레임에는 위기 확산, 책임 소재, 갈등 부각 등의 현저성이 두드러졌다. 특히 각 프레임을 구성하는 행위자는 가해자와 피해자라는 이분법적 대비 구조를 나타냈다. 기사에 등장하는 행위의 주체인 식품업자, 정부 및 해당관청, 소비자, 전문가 등은 이러한 갈등, 혹은 대비 구조의 프레임 안에서 때론 가해자로, 때로는 피해자로 틀짓기 되며 위험의 상황을 확산, 증폭 시키면서 소비자들의 혼란을 야기하고 위기의 사회현실을 구축하는 것으로 나타났다.

• 대한기계학회논문집B
• /
• 제23권11호
• /
• pp.1379-1389
• /
• 1999

A new technique for control of size and shape of flame-made particles is Introduced. The characteristic sintering time can be controlled Independently of collision time by heating the particles with irradiation of laser because the sintering time strongly depends on temperature. A coflow oxy-hydrogen diffusion flame burner was used for $SiCl_4$ conversion to silica particle. Nanometer sized aggregates irradiated by a high power CW $CO_2$ laser beam were rapidly heated up to high temperatures and then were sintered to approach volume-equivalent spheres. The sphere collides much slower than the aggregate, which results in reduction of sizes of particles maintaining spherical shape. Light scattering of Ar ion laser and TEM observation using a local sampling device were used to confirm the above effects. When the $CO_2$ laser was irradiated at low position from the burner surface, particle generation due to gas absorption of laser beam occurred and thus scattering intensity increased with $CO_2$ laser power. At high irradiation position, scattering intensity decreased with $CO_2$ laser power and TEM image showed a clear mark of evaporation and recondensation of particles for high $CO_2$ laser power. When the laser was irradiated between the above two positions where small aggregates exist, average size of spherical particles obviously decreased to 58% of those without $CO_2$ laser irradiation with the spherical shape. Even for increased carrier gas flow rate by a factor of three, TEM photograph also revealed considerable reduction of particle size.

• Journal of Chest Surgery
• /
• 제47권6호
• /
• pp.510-516
• /
• 2014

Background: Acute cerebral infarction is a major risk factor for postoperative neurologic complications in cardiac surgery. However, the outcomes associated with acute silent cerebral infarction (ASCI) have not been not well established. Few studies have reported the postoperative outcomes of these patients in light of preoperative Diffusion-weighted magnetic resonance imaging (DWI). We studied the postoperative neurologic outcomes of patients with preoperative ASCI detected by DWI. Methods: We retrospectively studied 32 patients with preoperative ASCI detected by DWI. None of the patients had preoperative neurologic symptoms. The mean age at operation was $68.8{\pm}9.5$ years. Five patients had previous histories of stroke. Four patients had been diagnosed with infective endocarditis. Single cerebral infarct lesions were detected in 16 patients, double lesions in 13, and multiple lesions (>5) in three. The median size of the infarct lesions was 4 mm (range, 2 to 25 mm). The operations of three of the 32 patients were delayed pending follow-up DWI studies. Results: There were two in-hospital mortalities. Neurologic complications also occurred in two patients. One patient developed extensive cerebral infarction unrelated to preoperative infarct lesions. One patient showed sustained delirium over one week but recovered completely without any neurologic deficits. In two patients, postoperative DWI confirmed that no significant changes had occurred in the lesions. Conclusion: Patients with preoperative ASCI showed excellent postoperative neurologic outcomes. Preoperative ASCI was not a risk factor for postoperative neurologic deterioration.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.215-216
• /
• 2013

The silicide is a compound of Si with an electropositive component. Silicides are commonly used in silicon-based microelectronics to reduce resistivity of gate and local interconnect metallization. The popular silicide candidates, CoSi2 and TiSi2, have some limitations. TiSi2 showed line width dependent sheet resistance and has difficulty in transformation of the C49 phase to the low resistive C54. CoSi2 consumes more Si than TiSi2. Nickel silicide is a promising material to substitute for those silicide materials providing several advantages; low resistivity, lower Si consumption and lower formation temperature. Nickel silicide (NiSi) nanowire (NW) has features of a geometrically tiny size in terms of diameter and significantly long directional length, with an excellent electrical conductivity. According to these advantages, NiSi NWs have been applied to various nanoscale applications, such as interconnects [1,2], field emitters [3], and functional microscopy tips [4]. Beside its tiny geometric feature, NW can provide a large surface area at a fixed volume. This makes the material viable for photovoltaic architecture, allowing it to be used to enhance the light-active region [5]. Additionally, a recent report has suggested that an effective antireflection coating-layer can be made with by NiSi NW arrays [6]. A unique growth mechanism of nickel silicide (NiSi) nanowires (NWs) was thermodynamically investigated. The reaction between Ni and Si primarily determines NiSi phases according to the deposition condition. Optimum growth conditions were found at $375^{\circ}C$ leading long and high-density NiSi NWs. The ignition of NiSi NWs is determined by the grain size due to the nucleation limited silicide reaction. A successive Ni diffusion through a silicide layer was traced from a NW grown sample. Otherwise Ni-rich or Si-rich phase induces a film type growth. This work demonstrates specific existence of NiSi NW growth [7].

• Journal of Pharmaceutical Investigation
• /
• 제1권1호
• /
• pp.101-108
• /
• 1971

The stability and toxicity test for p.p'-DDT, DDVP and dipterex that put to used sample in this study effects is follows A. about p.p'-DDT (1) In elevating the stability of p.p'-DDT, best stabilizing solvent was benzene. (2) The stability-agent has no difficulty as long as it not contain metal ion for instance $Z_n^{2+}$,$C_r^{3+}$,$Al^{3+}$,and $Fe^{2+or3+}$ but in case of contain $F_e^{3+}$, the combination of salicylaminoguanidine is best effective. (3) Using this product for water-suspension, We must use span 40 for stability agent and adding it at the same time. (4) We must use container which does not week alkali and metal ion but it is to preserved in tight light-resistant container. (5) The stopper of container is adapted with above-mentioned condition of container, but it is better not to use metal material. (6) This product needs opening ventilation more than 30 minutes after diffusion or spray and in the room we remove cause of remained poison by cleaning the bottom. B. about DDVP and Dipterex (1) Benzene or toluene in best solvent to preserve stability of DDVP and Dipterex. (2) Span 40 is superior for stability agent of this product and second is span 80. (3) The pH of solution is very stable in pH 5-6 and comparative stable in alkali more than p,p'-DDT. (4) Container is to preserved in tight, lightresistant container and especially be careful of outflow and inflow of water. (5) Because this product is centeral stimulant poison, we must pay attention to prevent cause of contact diadermic toxicity after use.

• 대한의용생체공학회:의공학회지
• /
• 제33권4호
• /
• pp.169-176
• /
• 2012

Tumor cell morphology is closely related to its migratory behaviors. An active tumor cell has a highly irregular shape, whereas a spherical cell is inactive. Thus, quantitative analysis of cell features is crucial to determine tumor malignancy or to test the efficacy of anticancer treatment. We use 3D time-lapse phase-contrast microscopy to analyze single cell morphology because it enables to observe long-term activity of living cells without photobleaching and phototoxicity, which is common in other fluorescence-labeled microscopy. Despite this advantage, there are image-level drawbacks to phase-contrast microscopy, such as local light effect and contrast interference ring. Therefore, we first corrected for non-uniform illumination artifacts and then we use intensity distribution information to detect cell boundary. In phase contrast microscopy image, cell is normally appeared as dark region surrounded by bright halo ring. Due to halo artifact is minimal around the cell body and has non-symmetric diffusion pattern, we calculate cross sectional plane which intersects center of each cell and orthogonal to first principal axis. Then, we extract dark cell region by analyzing intensity profile curve considering local bright peak as halo area. Finally, we calculated the Fourier descriptor that morphological characteristics of cell to classify tumor cells into active and inactive groups. We validated classification accuracy by comparing our findings with manually obtained results.

• 융합정보논문지
• /
• 제10권10호
• /
• pp.135-142
• /
• 2020

최근 농업분야에서는 드론의 보급으로 인하여 노령화를 해결하기 위한 4차 산업 혁명의 중요 기술로 분류되고 있다. 특히, 초경량비행장치 멀티콥터의 국가 자격증을 취득하고자하는 연령대가 다양하고 취득 후 수익 활동을 위한 분야로는 드론을 활용한 영상 촬영 및 방제가 대표적이다. 그러나 드론을 활용한 방제기술은 조종자의 조종 기술의 의존도가 높아 조종 숙련에 따라 살포효과의 차이가 발생한다. 이를 보완한다면 농업의 방제분야의 활용도가 다양해 질 것으로 기대된다. 대표적인 보완 기술은 농업용 방제드론의 기체 특성을 고려한 정확한 방제면적이 산출이다. 본 논문에서는 농업용 방제드론의 살포 특성 분석을 위하여 유효살포시간, 유효살포간격을 정식화하고 방제드론 종류에 따른 정확한 방제면적 산출이 가능한 알고리즘을 제안한다. 추후 본 알고리즘을 기반으로 드론방제사의 비행 방식에 따른 비산 문제를 개선하고 최적의 방제 매뉴얼을 구축하여 방제 현장에 활용하고자 한다.