• Korean Journal of Crystallography
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• v.4 no.1
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• pp.25-35
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• 1993

Tetra-tert-butyl-tetrapropionycalix (4) arena (C56H7208) is Triclinic, space group Pl, with a=13.664(5), b=17.585(5), c=12.863(2)A, a=109.33(2), B=111.97(2), γ=76.45(3) ˚, Z=2, V=2684.08A3, D, =1.152g/cm3, Dm=1.15g/cm3. The intensity data were collected on an Enraf-Nonius CAD-4 Diffractometer with a graphite monochromated Mo-Ka radiation. The structure was solved by direct methods and refined by leastsquares methods. The final R factor was 0.084 for 2561 observed reflections. The configuration of the molecule from the X-ray crystallographic investigation has the partial cone conformation, three tort-butylphenyls are down and a tort-butylphenyl is up. Three propionyloxy groups direct toward the exterior of the macrocycle cavity.

• Korean Journal of Crystallography
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• v.6 no.2
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• pp.80-87
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• 1995

The structure of Tetrapropionyloxycalix[4]arene(C40H40O8) has been studied by X-ray diffraction method. The crystal is monoclinic a=13.921(3), b=13.552(2), c=19.840(5)Å, β=110.38(2)°, Z=4 T=297K, Dc=1.23gcm-3, F(000)=1376, Systematic absences : hkl none, h0l : h+l=2n, 0k0: k=2n define space group P21/n. The structure was solved by direct method and refined by full-matrix least-squares methods to final R of 0.06 for 2514 observed reflections. The macrocycle exists in partial cone conformation. Three propionyl groups direct toward the exterior of the macrocycle cavity.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1288-1300
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• 1994

Mathematical modeling and numerical calculation on the flow and thermal characteristics induced by fire in a partial enclosure are performed. The solution procedures include the Shvab-Zeldovich approximation for the physical transport equations, low Reynolds number k-.epsilon. model for the turbulent fluid flow and Discrete Ordinate method(DOM) to calculate the radiative heat transfer. PMMA(Polymethylmethacrylate) is adopted as a solid fuel. Two different cases are considered : combustions with and without gas radiation occuring in a open cavity for variable pyrolyzing location of PMMA. When the fire source is located at the left-wall, the flow region of flame gas is limited at the left-wall and ceiling and recirculation region of inlet gas is formulated at neat the floor. In case of neglecting the radiative heat transfer, more large flame size and higher temperature is predicted. It is essential to consider the radiative heat transfer for analysis of fire phenomenon.

• Journal of Technologic Dentistry
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• v.44 no.1
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• pp.24-30
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• 2022

This research introduces the manufacturing process of the metal-framework of one of the maxillary partial dentures, the "obturator", using milling wax-blocks, for patients with palate loss due to oral cancer. It explains the protocol of taking the patient's oral impression, preparation of a working cast, scanning, designing using a computer-aided design program, investing the milling wax-blocks, and completing the obturator. This method does not follow the traditional wax and agar process thereby reducing the errors arising during the manufacturing process and decreasing the time, material, and labor required. Moreover, the retention, stability, and compatibility of the metal framework were observed to be high in both the working cast and oral cavity.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.2
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• pp.167-171
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• 2016

Patients undergone partial maxillectomy experience post-operative masticatory, phonetic, and swallowing difficulties. They also encounter social and psychological challenges due to changes in their facial appearances. Thus, functional and esthetic recovery through maxillofacial prosthesis becomes significant for these patients. The objective of an appropriate obturator is to restore palate and improve phonetic and swallowing ability by separating the oral cavity, nasal cavity, maxillary sinus, and nasopharynx. In this case report, an obturator was fabricated for a patient who had partial resection from the maxillary posterior region to the pharynx due to squamous cell carcinoma. The purpose of this case study is to describe the results because the patient was successfully improved both functionally and esthetically.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.86-90
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• 1998

Verrucous carcinoma is a variant of highly differentiated squamous cell carcinoma and has a predilection for the oral cavity and larynx. It is known to be of good prognosis due to its low regional and distant metastatic potential. Peak incidence is at ages 40-69 while predominantly occuring in males and its association with tobacco smoking has been implicated. The verrucous carcinoma have accordingly been treated by radiotherapy or surgical procedures but there has been considerable controversy regarding the effect of radiotherapy due to the possibility of anaplastic transformation Laser surgery and partial resection are among the commonly used surgical procedures but laser surgery has not yet shown results in improving phonetic abilities. Authors experienced two cases of verrucous carcinoma of the larynx treated by partial laryngectomy and false vocal cord advancement flap who showed no recurrence of disease under stroboscopic examination after two year follow up and when compared to preoperative aerodynamic studies, the expiratory air pressure was decreased and mean air flow rate increased which improved glottal efficiency markedly.

• Korean Journal of Optics and Photonics
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• v.14 no.1
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• pp.85-91
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• 2003

Intracavity frequency doubling of a single-mode Nd:YAG laser by using a nonplanar ring cavity is demonstrated. The nonplanar ring cavity consists of a Brewster-angled Nd:YAG crystal placed in a magnetic field, a KTP crystal, and two spherical mirrors. In this design the Nd:YAG block acts as both a nonreciprocal polarization rotator and a partial polarizer, and the nonplanar portion of the ring cavity, which is formed by a relative twist angle between the Brewster-angled end surfaces of the Nd:YAG block, serves as a reciprocal polarization rotator. An eigenpolarization theory for the cavity configuration is presented and suitable values of the relative twist angle for unidirectional operation are estimated. A single-mode output power of 22 ㎽ at 532 nm and an optical to optical conversion efficiency of 1.8% are obtained with a 1.2 W diode laser at 809 nm.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.6
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• pp.482-489
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• 2018

Most of the numerical and experimental studies on supercavitating flows are focused on the cavitator only. However, the partial cavity growing into the supercavity is affected by the shape of the body placed behind the cavitator. In this paper, we develope a numerical method which is based on the boundary element method to predict supercavitating flow around three-dimensional axisymmetric bodies. We estimate the influence of the body shape on the supercavity growth. Here, we consider various parameters of the body such as cavitator shape, shoulder length and body diameter, and compare the results with the case of the cavitator only. In summary, it is found that the body may impede the cavity growth, the shoulder mainly affects the cavity length, and the supercavity occurring in the cone type cavitator is strongly influenced rather than that of the disk type cavitator.

• Journal of Advanced Marine Engineering and Technology
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• v.15 no.4
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• pp.46-53
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• 1991

In the present study, Navier-Stokes equation is numerically solved by use of a Finite analytic method to obtain the 2-dimensional flow field in the square cavity. The basic idea of F.A.M. is the incorporation of local analytic solutions in the numerical solution of linear or non-linear partial differential equations. In the F.A.M., the total problem is subdivided into a number of all elements. The local analytic solution is obtained for the small element in which the governing equation, if non-linear, to be linearized. The local analytic solutions are then expressed in algebraic form and are overlapped to cover the entire region of the problem. The assembly of these local analytic solutions, which still preserve the overall nonlinearity of the governing equations, results in a system of linear algebraic equations. The system of algebraic equations is then solved to provide the numerical solutions of the total problem. The computed flow field shows the same characteristics to physical concept of flow phenomena.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.208-213
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• 2002

A new method is presented for the isolation of resonances from scattered waves for elastic wave resonance scattering problems. The resonance scattering function consisting purely of resonance information is defined. Elastic wave resonance scattering from a water-filled cylindrical cavity imbedded in an aluminum matrix is numerically analyzed. The classical resonance scattering theory and the new method compute different magnitudes and phases of the resonances from each partial wave, and therefore. their total resonance spectra are quite different. The exact $\pi$ - radians phase shifts through the resonance and anti-resonance frequencies show that the proposed method properly extracts the vibrational resonance information of the scatterer compared to resonance scattering theory.