• Journal of the Korean Vacuum Society
• /
• v.7 no.3
• /
• pp.187-194
• /
• 1998

InGaAsP epitaxial layers lattice matched to InP were grown at 600 and $620^{\circ}C$ by low pressure metalorganic chemical vapor deposition. Solid phase composition of group III was controlled by the diffusion flux gas phase to the reachion surface. For the case of group V, the difference of As and P vapor pressure and pyrolysis efficiency of $PH_3$and $AsH_3$ mainly determined their in corporation into solid. An abnormal behavior of peak energy shift was observed below 75K in temperature variant photoluminescence study. This abnormal behavior was explained by the difference in order of ordering which makes spatial variation of energy gap in InGaAsP layer and this explanation was supported by the analyses of transmission electron microscopy and transmission spectroscopy.

• Design & Manufacturing
• /
• v.2 no.6
• /
• pp.11-16
• /
• 2008

In order to satisfy the customer's variant needs for a product quality in recent years, a demand for developing higher precision machining technologies in a lot of application areas such as automobile, cellular phone and semiconductor has been increased more and more. Micro-magnetic induced polishing(${\mu}-MIP$) process is one of these precision technologies. In this study, to verify the parameters' effect of the ${\mu}-MIP$ process on the surface roughness improvement of the inclined workpiece, well planned experiment which was called the design of experiments was carried out. Considered parameters were spindle speed, inductor current, abrasive configuration and working gap between the workpiece and the solid tool. As a result, it was seen that the inductor current and the working gap greatly affected the surface roughness improvement. And to predict the surface roughness of the inclined workpiece, S/N ratio and first-order response surface model was developed.

• Journal of Pharmaceutical Investigation
• /
• v.41 no.6
• /
• pp.381-386
• /
• 2011

Multi-drug resistance (MDR) has been known as a major hurdle in cancer chemotherapy. One of the most clinically significant causes of MDR was the efflux of anticancer agents mediated by p-glycoprotein (p-gp) over-expressed in MDR cancer cells. To overcome MDR, there have been several strategies such as co-administration with p-gp inhibitors and encapsulation of anticancer drugs into drug delivery systems. In the present study, curcumin was evaluated for its potential as p-gp inhibitor and MDR reversal activity when combined with paclitaxel incorporated into lipid nanoparticles (PTX/LN). Western blot assay showed curcumin did not modulate the level of p-gp expression in MCF-7/ADR which is a MDR variant of human breast cancer cell line, MCF-7, and over-expresses p-gp. However, curcumin inhibited p-gp-mediated efflux of calcein in a dose-dependent manner even though it showed lower activity compared to verapamil, a well-known p-gp inhibitor. Incorporation of paclitaxel into lipid nanoparticles partially recovered the anticancer activity of paclitaxel in MCF-7/ADR. The combined use of curcumin and PTX/LN exhibited further full reversal of MDR, suggesting susceptibility of PTX/LN to the efflux system. In conclusion, combined approach of using p-gp inhibitors and incorporation of the anticancer agents into nano-delivery systems would be an efficient strategy to overcome MDR.

• Journal of Korean Neurosurgical Society
• /
• v.51 no.6
• /
• pp.377-379
• /
• 2012

Mucosa-associated lymphoid tissue (MALT) lymphoma is one of the most common lymphomas and accounts for about 7% of all newly diagnosed non-Hodgkin's lymphoma (NHL). The clinical course of MALT lymphoma is relatively indolent and, in the majority of cases (50%), the lymphoma arises within the stomach. Primary central nervous system lymphoma (PCNSL), an uncommon variant of extranodal NHL, can affect any part of the neuraxis, including the eyes, brain, leptomeninges, or spinal cord. Herein, we present a rare case of PCNSL, which occurred one year after radiochemotherapy of gastric MALT lymphoma. A 62-year-old man presented with a 3-day history of left facial palsy. One year ago, he underwent antibiotic eradication therapy of Helicobacter pylori, local stomach fractional radiotherapy, and chemotherapy for gastric MALT lymphoma. Magnetic resonance imaging revealed a strong enhancing solid mass in the right frontal lobe. The tumor was completely removed, and the histological diagnosis of PCNSL developing from diffuse large B-cell lymphoma was made. Although elucidating the correlation between the first gastric MALT lymphoma and the second PCNSL seemed difficult, we have postulated and discussed some possible pathogeneses, together with a review of literature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.213-217
• /
• 2011

Unsteady numerical simulations of pintle nozzles were implemented for solid rocket thrust vector control. The variation of pintle location was considered using unsteady numerical techniques, and dynamic characteristics of various pintle models were investigated. In order to consider the variation of the pintle location, a moving mesh method was applied. The effects of shape and location of the pintle nozzle have been analytically investigated. And the results were compared with numerical results. The chamber pressure, mass flow and thrust are analyzed to take account dynamic characteristics of pintle performance.

• Korean Journal of Computational Design and Engineering
• /
• v.5 no.2
• /
• pp.103-112
• /
• 2000

CAD databases are the core element to the management of product information. A key to the successful use of the databases is a rational method of query to and retrieval from the databases. Although it is parts geometry that users eager to retrieve from the CAD databases, no system yet supports geometry-based query. This paper aims at developing a new method of assessing geometric similarity which can serve as the basis of geometric query for CAD database. The proposed method uses ASVP (Alternating Sums of Volumes with Partitioning) decomposition that is a volumetric representation of a part obtained from its boundary representation. A measure of geometric similarity between two solid models is defined on their ASVP tree representations. The measure can take into account overall shapes of parte, shapes of features and their locations. Several properties that a similarity measure needs to satisfy are discussed. The geometric query developed in this paper can be used in a wide range of applications using CAD databases, which include similarity-based design retrieval, variant process planning, and components selection from part library. An experiment has been carried out to demonstrate the effectiveness of the method, and the results are presented.

• Korean Journal of Head & Neck Oncology
• /
• v.28 no.1
• /
• pp.27-30
• /
• 2012

Basaloid squamous cell carcinoma(BSCC) is a high-grade variant of squamous cell carcinoma, with a prediction for multifocal involvement of the base of tongue, pyriform sinus, supraglottic larynx, hypopharynx and palatine tonsil. It primary affects men in the seventh decade of life with frequent cervical lymph-node metastasis at presentation. Grossly, these tumors are usually firm to hard, with associated central necrosis, occuring as exophytic to nodular masses. Histologically, the this infiltrating tumor offers a variety of growth patterns, including solid, lobular, cribriform, cords, trabeculae, nests and glands or cyst. We present a 55-year-old female who was treated with surgical excision and radiotherapy. She was firstly presented as a recurrent inflammatory neck mass and finally diagnosed with basaloid squamous cell carcinoma in the palatine tonsil.

• Korean Journal of Head & Neck Oncology
• /
• v.20 no.2
• /
• pp.189-193
• /
• 2004

Basaloid squamous carcinoma (BSC) is an uncommon aggressive variant of squamous cell carcinoma with a predilection for hypopharynx, tongue base, and larynx. We present 5 cases of BSC of unusual sites, each from maxillary sinus, external auditory canal, submandibular gland, tonsil, and nasopharynx. Only a few cases arising in these sites have been reported to date. Patients included 3 men and 2 women with the age range of 45-69 years (mean, 56.4 years). Microscopically, the tumors were characterized by solid lobules and nests of ovoid basaloid cells with abundant desmoplastic stroma. Comedonecrosis, peripheral palisading of tumor cells, trabecular pattern, and rosette-like arrangement were commonly observed. Tumor cells had scanty cytoplasm and their nuclei were ovoid, relatively uniform, and hyperchromatic. In two cases, concomitant squamous cell carcinoma in situ was identified. Immunohistochemical stains revealed that tumor cells were strongly positive for pancytokeratin and negative or weakly positive for p63. Being aware of BSC that can arise from unusual sites would help diagnose correctly and treat properly this rare and distinct clinicopathologic entity.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.2
• /
• pp.1-8
• /
• 2015

Dual pulse rocket motor is a variant of solid rocket motor with two propellant grain separated by a pulse separation device. The major performance of such a rocket motor is influenced by the change in the hole area of pulse separation device to nozzle throat area ratio. In this study, we performed flow analysis to investigate the internal flow characteristics according to the pulse separation device hole area to nozzle throat area ratio change. Gases used flow analysis were used combustion gas of HTPB/AP composite propellant and nitrogen gas. Flow analysis results of the dual pulse rocket motor were validated by comparison with experimental results of pneumatics. Commercial CFD code ANSYS FLUENT 14.5 is used in this study to simulate flow analysis.

• Korean Journal of Radiology
• /
• v.23 no.7
• /
• pp.763-772
• /
• 2022

Objective: Preoperative differential diagnosis of follicular-patterned lesions is challenging. This multicenter cohort study investigated the clinicoradiological characteristics relevant to the differential diagnosis of such lesions. Materials and Methods: From June to September 2015, 4787 thyroid nodules (≥ 1.0 cm) with a final diagnosis of benign follicular nodule (BN, n = 4461), follicular adenoma (FA, n = 136), follicular carcinoma (FC, n = 62), or follicular variant of papillary thyroid carcinoma (FVPTC, n = 128) collected from 26 institutions were analyzed. The clinicoradiological characteristics of the lesions were compared among the different histological types using multivariable logistic regression analyses. The relative importance of the characteristics that distinguished histological types was determined using a random forest algorithm. Results: Compared to BN (as the control group), the distinguishing features of follicular-patterned neoplasms (FA, FC, and FVPTC) were patient's age (odds ratio [OR], 0.969 per 1-year increase), lesion diameter (OR, 1.054 per 1-mm increase), presence of solid composition (OR, 2.255), presence of hypoechogenicity (OR, 2.181), and presence of halo (OR, 1.761) (all p < 0.05). Compared to FA (as the control), FC differed with respect to lesion diameter (OR, 1.040 per 1-mm increase) and rim calcifications (OR, 17.054), while FVPTC differed with respect to patient age (OR, 0.966 per 1-year increase), lesion diameter (OR, 0.975 per 1-mm increase), macrocalcifications (OR, 3.647), and non-smooth margins (OR, 2.538) (all p < 0.05). The five important features for the differential diagnosis of follicular-patterned neoplasms (FA, FC, and FVPTC) from BN are maximal lesion diameter, composition, echogenicity, orientation, and patient's age. The most important features distinguishing FC and FVPTC from FA are rim calcifications and macrocalcifications, respectively. Conclusion: Although follicular-patterned lesions have overlapping clinical and radiological features, the distinguishing features identified in our large clinical cohort may provide valuable information for preoperative distinction between them and decision-making regarding their management.