• Journal of the Korean Society of Propulsion Engineers
• /
• v.10 no.1
• /
• pp.23-29
• /
• 2006

In an annular injection supersonic ejector, the supersonic primary flow is injected along the side wall, therefore a funnel-shaped shock wave is generated by the contraction angle of the mixing chamber. In the present study, we developed a simple funnel shock wave model using 2-D wedge and conical shock wave relations. In result, the secondary flow pressure can be predicted more accurately than using a simple 2-D wedge shock wave model. Through the same analysis, the compression ratio and the adiabatic efficiency according to the entrainment ratio were calculated.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.7 no.3
• /
• pp.45-52
• /
• 2003

Detailed flowfield resulting from the secondary sonic gas injection into a divergent section of supersonic conical nozzle has been numerically investigated. The three-dimensional flowfield associated with the bow-shock/boundary-layer interaction inside the nozzle has been solved by Reynolds-averaged Navier-Stokes equations with an algebraic and $\kappa$-$\varepsilon$ turbulence model. The numerical results have been compared with the experimental results for the identical flow conditions, and it is shown that the comparison is satisfactory Effects of different injection pressures of the secondary jet on the shock/boundary-layer interactions and the overall flow structure inside the nozzle have been investigated. The vortex structures behind the shock interaction and wall pressure variations have also been studied.

• Horticultural Science & Technology
• /
• v.31 no.5
• /
• pp.590-597
• /
• 2013

Principle component and emission localization of volatile compounds were investigated according to scent intensity of rose flower. Scent intensity in cultivars and bred-line of Rosa hybrida was divided into three levels; light ('Feel Lip', 'Venus Berry'), medium ('GR07-135'), strong ('Honey Blue'). The major volatile compounds were different depending on the cultivars and selected line; 3,5-dimethoxytoluene (DMT), benzene, 1,3,5-trimethoxy ('Feel Lip'), megastigma-4,6(Z),8(E)-triene ('Venus Berry'), DMT, benzene,1-ethenyl-4-methoxyand, phenylethylalcohol ('GR07-135') and germacrene-D, DMT ('Honey Blue'). The adaxial epidermal cells were conical papillate shape, whereas the abaxial epidermal cells were flat shape. The adaxial epidermal cells of 3 cultivars and 1 selected line were surrounded by thick cell wall and covered by waxy cuticle of 2 cultivars and 1 selected line (except 'Honey Blue'). The adaxial epidermal cells contained starches in 'Feel Lip', osmiophlic droplets in 'Venus Berry', starchs, plastids, vacuoles in 'GR07-135' and plastoglobules, plastids, vacuoles in 'Honey Blue'. Based on these results, it appears that plastids and vacuoles in adaxial epidermal cells with conical papillate shape are associated production and emission of volatile compounds in scent R. hybrida.

• Animal Systematics, Evolution and Diversity
• /
• v.20 no.2
• /
• pp.201-214
• /
• 2004

Some actiniarians were collected from the coasts of Jejudo and Baekdo Islands in Korean waters from 1971 to 2004. They are identified into three species within three families, which are newly recorded to Korean actiniarian fauna: Halcampella maxima Hertwig, 1888 within the tribe Athenaria, and also Aulactinia coccinea (Verrill, 1866) and Stichodactyla tapetum (Ehrenberg, 1834) within the tribe Thenaria. They are described in detail with figures and tables together with the distribution and size of cnidae. In preserved specimens, mature oocytes of H. maxima were observed in winter. Also oocytes and sperm sacs of S. tapetum were surveyed at separate individuals in summer. The unique feature of A. coccinea is a body wall with simple adhesive verrucae extended from margin to limbus in longitudinal rows. In the genus Stichodactyla, the smallest species, S. tapetum is distinguished from S. haddoni by short bulbous tentacles, less than 1.0 mm long, densely packed on the oral disc and also conical marginal ones, 1.5-2.0 mm long. As a result of this study, the Korean actiniarian fauna consists of four athenarian and 23 thenarian species in suborder Nynantheae

• Nuclear Engineering and Technology
• /
• v.52 no.2
• /
• pp.397-416
• /
• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part II, based on the verified finite element (FE) models of aircrafts Airbus A320 and A380, as well as the NPP containment and auxiliary buildings in Part I of this paper, the whole collision process is reproduced numerically by adopting the coupled missile-target interaction approach with the finite element code LS-DYNA. The impact induced damage of NPP plant under four impact locations of containment (cylinder, air intake, conical roof and PCS water tank) and two impact locations of auxiliary buildings (exterior wall and roof of spent fuel pool room) are evaluated. Furthermore, by considering the inner structures in the containment and raft foundation of NPP, the structural vibration analyses are conducted under two impact locations (middle height of cylinder, main control room in the auxiliary buildings). It indicates that, within the discussed scenarios, NPP structures can withstand the impact of both two aircrafts, while the functionality of internal equipment on higher floors will be affected to some extent under impact induced vibrations, and A380 aircraft will cause more serious structural damage and vibrations than A320 aircraft. The present work can provide helpful references to assess the safety of the structures and inner equipment of NPP plant under commercial aircraft impact.

• Radiation Oncology Journal
• /
• v.6 no.1
• /
• pp.23-33
• /
• 1988

A rerospective review of fifty patients with carcinoma of hypopharynx treated with $RT{\pm}surgery$ was studied for eleven-year period from 1974 to 1984. Of the 50 patients,46 were pyriform sinus in origin, 4 were posterior pharyngeal wall. Eighty-eight percent of patients were locoregionally advanced(stage III, IV) and 78% of patients presented conical lymphadenopathy. 5-year disease-free survival rate of the pyriform sinus ca. was $25.4\%$ in RT alone group, $80\%$ in combined modality group and $30.6\%$ in overall. Local control rate with RT alone in early stage (II) was excellent $(100\%)$, however combined modality appears to be better for local control$(80\%)$ in advanced stage (III, IV) as compared with that of RT alone group $(32\%).$ On basis of this study, RT alone is effective in terms of local control and functional preservation in treatment of early stage of pyriform sinus ca. while surgery can be reserved for salvage purpose when RT fails and combined modality is recommended in patients with locally advanced stage for better local control and survival.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.15 no.3
• /
• pp.399-407
• /
• 2002

A three-dimensional method of analysis is presented for determining the free vibration frequencies and mode shapes of hollow bodies of revolution (i.e., thick shells), not limited to straight line generators or constant thickness. The middle surface of the shell may have arbitrary curvatures, and the wall thickness may vary arbitrarily. Displacement components$U_\Phi, U_z, U_\theta$ in the meridional, normal and circumferential directions, respectively, are taken to be sinusoidal in time, periodic in$\theta$, and algebraic polynomials in the$\Phi$and z directions. Potential(strain) and kinetic energies of the entire body are formulated, and upper bound values of the frequencies are obtained by minimizing the frequencies. As the degrees of the polynomials are increased, frequencies converge to the exact values. Novel numerical results are presented for two types of thick conical shells and thick spherical shell segments having linear thickness variations. Convergence to four digit exactitude is demonstrated for the first five frequencies of both types of shells. The method is applicable to thin shells, as well as thick and very thick ones.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.16 no.2
• /
• pp.197-206
• /
• 2003

A three-dimensional (3-D) method of analysis is presented for determining the free vibration frequencies and mode shapes of solid and hollow hemispherical shells of revolution of arbitrary wall thickness having arbitrary constraints on their boundaries. Unlike conventional shell theories, which are mathematically two-dimensional (2-D), the present method is based upon the 3-D dynamic equations of elasticity. Displacement components μ/sub Φ/, μ/sub z/, and μ/sub θ/ in the meridional, normal, and circumferential directions, respectively, are taken to be sinusoidal in time, periodic in θ, and algebraic polynomials in the Φ and z directions. Potential (strain) and kinetic energies of the hemispherical shells are formulated, and the Ritz method is used to solve the eigenvalue problem, thus yielding upper bound values of the frequencies obtained by minimizing the frequencies. As the degree of the polynomials is increased, frequencies converge to the exact values. Novel numerical results are presented for solid and hollow hemispheres with linear thickness variation. The effect on frequencies of a small axial conical hole is also discussed. Comparisons are made for the frequencies of completely free, thick hemispherical shells with uniform thickness from the present 3-D Ritz solutions and other 3-D finite element ones.

• Journal of Energy Engineering
• /
• v.8 no.2
• /
• pp.298-308
• /
• 1999

Experimental study on characteristics of direct contact condensation of steam discharged into a sub-cooled water pool has been performed using five different sizes of horizontal nozzle over a wide range of steam mass fluxes and pool temperatures. Steam condensation phenomena have been observed visually and by taking pictures of steam jets using a high speed video camera. Two different steam jet shapes such as ellipsoidal shape and conical shape were typically observed for a stable steam jet, depending on the steam mass flux and pool temperature. The steam jet expansion ratio and the steam jet length as well as the condensation heat transfer coefficients were determined. The effect of steam mass flux, pool temperature, and nozzle diameter on these parameters were also discussed. Empirical correlations for the steam jet lengths and the condensation heat transfer coefficients as a function of steam mass flux and condensation driving potential were established. The axial and radial temperature distributions in steam jet and in surrounding water were measured. The effect of steam mass flux, pool temperature, and nozzle diameter were also discussed. The condensation regime map, which consists of six regimes such as chugging, transient chugging, condensation oscillation, stable condensation, bubble condensation oscillation, and intermittent oscillation condensation, were established. In addition, the dynamic pressures at the pool wall were measured. The close relation of dynamic pressure and steam condensation mode, which is also dependent on steam mass flux and pool temperature, was found.

• Journal of Veterinary Clinics
• /
• v.11 no.2
• /
• pp.529-537
• /
• 1994

Sector scanner which has a conical end is used to image through the intercostal space because heart is protected by the ribs. Cardiac data published all around the world were also obtained by sector scanner. Although scanners being used in every small animal practice and animal hospital at college in Korea include convex ape and linear type, linear type is not appropriate f3r cardiac scan because of a wide contact surface. The purpose of this study is to establish ultrasonographic images of normal cardiac structures by measuring shape, size of reflectable cardiac structure according to restraint position in scanning normal heart of the puppies with 6.5 MHz convex scanner(SonoAce 4500, Medison, Korea) used in our veterinary teaching hospital, Seoul national university. Seventeen male and female puppies considered having healthy hear by X-ray and clinical examination are used feom April to July 1994. Scanning point selection of probe head and the distinction of imaged cardiac structures were accomplished by necropsy and cardiac scanning performed through thoracotomy under general anesthesia. At 10 o'clock position of transducer(at an angle of 30$^{\circ}$ between imaginary line from elbow joint to 3rd sternum and probe head, 60$^{\circ}$ from body surface, 4th intercostal space of right thorax) with the marker of scanner toward the head of dogs right atrium, left atrium and left ventricle were observed in 2, 3, 4, 5 intercostal space(2cm from the sternum) of experimental dog positioned ventrodorsally under general anesthesia. Under these conditions, the numerical values of imaged diastolic hear are as follows : the distance from skin to apex(mean$\pm$S.D) 47.53$\pm$6.94mm, thickness of left ventricular wall 6.00$\pm$1.60mm, length of left ventricle 16.27$\pm$5.31mm, width of left ventricle 15,33$\pm$4.25mm, length of left atrium 12.33$\pm$3.82mm, width of left atrium 11. 33$\pm$3.94mm, length of right atrium 1.00$\pm$2.41mm, width of right atrium 11.21$\pm$2.76mm and the area of left ventricle 270.92$\pm$109.81mm$^2$, area of left atrium 98.00$\pm$41.08mm$^2$, area of right atrium 62.75$\pm$21.04mm$^2$.