• 대한의용생체공학회:의공학회지
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• 제43권2호
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• pp.94-101
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• 2022

Recent advancement of micro/nano technology enables the development of diverse micro/nano particle-based delivery systems. Due to the multi-functionality and engineerability, particle-based delivery system are expected to be a promising method for delivery to the target cell. Since the particle-based delivery system should be delivered to the various kinds of target cell, including the cardiovascular system, cancer cell etc., it is frequently decorated with multiple kinds of targeting molecule(s) to induce specific interaction to the target cell. The surface decorated molecules interact with the cell surface expressed molecule(s) to specifically form a firm adhesion. Thus, in this study, the probability of adhesion is estimated to predict the possibility to form a firm adhesion for the multi-ligand decorated particle-based delivery system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1788-1793
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• 2008

Classical molecular dynamics simulations (MDS) were conducted to simulate nano-sized cluster collisions with a weakly attractive static surface. Energy exchanges associated with the cluster collision and the adhesion probability are discussed. Routes of the energy exchanges and the kinetic energy loss are vastly altered in their mode according to the cluster incident velocity. In the elastic collision regime ($V_0$<0.1), most incident kinetic energy is recovered into the rebounding kinetic energy, but a little loss in the incident kinetic energy causes the cluster adhesion. Dissipated kinetic energy is converted into the rotational energy. In the weakly plastic collision regime (0.1<$V_0$<0.3), the transition from elastic to plastic collision occurs, and a large part of the released potential energy is converted into rebounding translational energy. For strongly plastic collisions ($V_0$>0.3), permanent cluster deformation occurs with extensive collapse of the lattice structure inducing a solid-to-solid phase transition; moreover, most of the cluster kinetic energy is converted into cluster potential and thermal energy.

• 대한의용생체공학회:의공학회지
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• 제43권2호
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• pp.71-80
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• 2022

The interaction between dual-ligand decorated particle-based delivery system and target cell under shear flow is predicted using probability model developed. We assumed the two kinds of ligand are decorated on the surface of the particle with 10% length difference. Fixed with other biophysical parameters, a study on the particle-cell interaction for the different non-specific interaction parameter is performed. To induce the firm adhesion, short ligand-receptor should be engaged. Also, it is shown that the rational design of ligand-receptor interaction, including receptor number, specific interaction parameter, kinds of ligand-receptor, etc., should be considered.

• 반도체디스플레이기술학회지
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• 제9권1호
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• pp.5-10
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• 2010

Among a variety of cleaning processes, the cryogenic carbon dioxide ($CO_2$) cleaning has merits because it is highly efficient in removing very fine particles, innoxious to humans and does not produce residuals after the cleaning, which enables us to extend its area of coverage in the semi-conductor fabrication society. However, the cryogenic carbon dioxide cleaning method has some technical research issues in aspect to particles' adhesion and removal. To resolve these issues, performing an analysis for the identification of particle adhesion mechanism is needed. In this study, a research was performed by a theoretical approach. To this end, we extended the G-T (Greenwood-Tripp) model by applying the JKR (Johnson-Kendall-Roberts) and Lennard-Jones potential theories and the statistical characteristics of rough surface to investigate and identify the contact, adhesion and deformation mechanisms of soft or hard particles on the rough substrate. The statistical characteristics of the rough surface were taken into account through the employment of the normal probability distribution function of the asperity peaks on the substrate surface. The effects of surface roughness on the pull-off force for these particles were examined and discussed.

• 한국전기전자재료학회논문지
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• 제20권12호
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• pp.1027-1033
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• 2007

In this research, the polishing pad for W CMP has been analyzed to understand stabilization of polishing performance. For stabilization of process, the polishing pad condition is one of important factors. The polishing pad plays a key role in polishing process, because it contact with reacted surface of wafer[1]. The physical property of pad surface is ruled by conditioning tool which makes roughness and profile of pad surface. Pad surface affects on polishing performance such as RR(Removal Rate) and uniformity in CMP. The stabilized pad surface has stable roughness. And its surface has high level of wettability which can increase the probability of abrasive adhesion on pad. The result of this research is that the reduction of break-in and dummy polishing process were achieved by artificial machining to make stable pad surface. In this research, urethane polishing pad which is named IC pad(Nitta-Haas Inc.) and has micro pore structure, is studied. Because, this type of pad is the most conventional type.

• Archives of Pharmacal Research
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• 제29권1호
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• pp.1-15
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• 2006

Vascular endothelial cell injury or dysfunction has been implicated in the onset and' progression of cardiovascular diseases including atherosclerosis. A number of previous studies have demonstrated that the pro-oxidative and pro-inflammatory pathways within vascular endothelium play an important role in the initiation and progression of atherosclerosis, Recent evidence has provided compelling evidence to indicate that interleukin-4 (IL-4) can induce proc inflammatory environment via oxidative stress-mediated up-regulation of inflammatory mediators such as cytokine, chemokine, and adhesion molecules in vascular endothelial cells. In addition, apoptotic cell death within vascular endothelium has been hypothesized to be involved in the development of atherosclerosis. Emerging evidence has demonstrated that IL-4 can induce apoptosis of human vascular endothelial cells through the caspase-3-dependent pathway, suggesting that IL-4 can increase endothelial cell turnover by accelerated apoptosis, the event which may cause the dysfunction of the vascular endothelium. These studies will have a high probability of revealing new directions that lead to the development of clinical strategies toward the prevention and/or treatment for individuals with inflammatory vascular diseases including atherosclerosis.

• 한국정밀공학회지
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• 제26권8호
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• pp.112-118
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• 2009

A pressure rise is generated while air bearing stages are moving in high vacuum environment. This study analyzed this pressure rise phenomenon theoretically and verified it experimentally using two different kinds of stages - linear and rotary air bearing stages. Results indicate that the pressure rise was caused by additional leakage resulting from stage velocity, along with adsorption and outgassing of gas molecules from the guide rail surface. Though tilting of the stage due to acceleration and deceleration reached several micrometers, it had a negligible effect on pressure rise because the tilting time was very short. Therefore, a rotary air bearing stage showed much less pressure rise than a linear stage because the rotary stage theoretically has nothing to do with the above causes. Additional leakage caused by stage velocity was inevitable if the stage had movements, but pressure rise caused by adsorption and outgassing could be suppressed by improving the surface quality to reduce real surface area, and by coating the guide rail surface with titanium nitride (TiN) which has less adhesion probability of gas molecules. The results also indicate that the pressure rise increased when the air bearing stage operated under high vacuum conditions.

• 자원리싸이클링
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• 제5권4호
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• pp.11-16
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• 1996

부유선별법에 의한 탈묵공정에서 잉크입자와 기포의 부착은 상호간의 충돌에 의한 것인데, 충돌의 가능성은 주로 수력학적 조건에 지배된다. 따라서, 부유선별법에서 미세입자의 제거효율이 낮은 이유는 수력학적 영향에 의해 입자가 기포주위의 수층유선을 따라 흘러내리는 경향이 있으므로 기포와의 충돌이 어렵기 때문이라고 해석되어 진다. 또한, 크고 무거운 잉크입자의 경우에는 기포에 의한 부상과정에서 중력과 점성력 등의 영향을 크게 받으므로 부유선별에 의한 제거가 어렵다고 간주되어 진다. 따라서, 부유선별의 실제공정에서는 계면화학적 측면에서의 조건선정 뿐만 아니라, 잉크입자와 기포의 크기를 조절하는 수력학적 관점에서의 조절이 또한 중요하다.

• 대한두경부종양학회지
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• 제13권1호
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• pp.30-34
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• 1997

Objectives: Calcification of the thyroid nodule has been reported to have a close relationship with differentiated thyroid carcinoma, however there are limited studies on the relationship between the calcified thyroid nodule and thyroid malignancy. The authors studied the clinical significance of calcification within the thyroid nodule. Materials and Methods: There were total of 60 patients who underwent surgery for calcified thyroid nodules which were identified from plain neck X-ray, ultrasound and computed tomography during the period January 1991 to June 1996 at the Department of Otorhinolaryngology-Head and Neck Surgery of Korea University Hospital. Six patients were not included because of recurrence and previous thyroid surgery. Histopathologic and radiologic analysis was done on the remaining 54 patients. Results: Results showed that 25 of 54 cases(46%) to be malignant histopathologically. Of the 25 malignant cases, papillary carcinoma was the most common with 22 cases followed by 2 cases of undifferentiated carcinoma and I case of medullary carcinoma. Statistically high incidence of malignancy was observed when the consistency of calcified thyroid nodule was solid, shape of calcification was irregular and inhomogenous, and adhesion of calcified thyroid nodule to the regional structure was present. Conclusion: The probability that a thyroid nodule is malignant has been reported to be 3­20%. However, about half of the thyroid nodules with calcification found to be malignant on this study, calcification of the thyroid nodule can be used as a guideline for detecting thyroid malignancy.

• 사상체질의학회지
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• 제12권2호
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• pp.171-183
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• 2000

1. Back ground and purpose An experimental study has done to examine the effect of defense and cure gastric mucasal damage of Mokdan-pijihwang-tang. 2. Methods Mice had intragastric injected with MJ extract before indomethacin treatment which induces homorrhage infarct and erosion artificially. Degree of lipid peroxidation, general morphology, change of mucous cell, the distribution of PNA, ICAM and distribution of apoptotic cell were objected. (Abbreviation) MJ : Mokdanpijihwang-tang, PNA : Peanut Agglutinin, ICAM : Intercellular Adhesion Molecule 3 Results 1) The degree of lipid peroxidation in INDO-group had increased conspicuously than control group. But the degree of lipid peroxidation in MJ-group had decreased than INDO-group and these decline had probability. 2) After indomethacin treatment, hemorrhage infarct and erosion had increased in stomach body. But in MJ-group, the configuration is normal, except the group intragastric injected with MJ extract at hour 24 before indomethacin treatment. 3) Surface mucous cell and neck mucous had disappeared in INDO-group. But in MJ-group tormal distribution had shown like control group except the group intragastric injected with MJ extract at hour 24 before indomethacin treatment. 4) PNA positive reaction had not shown in INDO-group. But medium PNA positive reaction had shown In Mj-group. 5) ICAM positive reacted cell had shown in INDO-group. The decrease of ICAM positive cell were shown than INDO-group. 6) A number of apoptotic cell was distributed in hemorrhagic erosion. A few number of apoptotic cell was distributed in MJ-group except some surface mucous. 4. Conclusion These results suggest that MJ has an effect on cure of gastric mucosal damage.