• International Journal of Air-Conditioning and Refrigeration
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• 제9권2호
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• pp.77-84
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• 2001

Experimental and computational studies were carried out to investigate the turbulent heat transfer enhancement of the cooling system in nuclear reactor by large scale vortex generation. The large scale vortex motion was generated by rearranging the inclination angels of mixing vanes to the coordinate direction. Axial development of mean and turbulent velocities in the subchannels were measured by the 2-color LDV system. Eddy diffusivity concept based on $\kappa{-}\varepsilon$ model was employed to calculate the turbulent heat and momentum transfers in the subchannel. The turbulences generated by split mixing vanes has small length scales so that they maintain only about $10D_H$ after the spacer grid. On the other hand, the turbulences generated by the large scale vortex motions continue longer and remain up to $25D_H$ after the spacer grid.

• 설비공학논문집
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• 제12권11호
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• pp.1004-1011
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• 2000

Experimental and computational studies were carried out to confirm the turbulent enhancement of the cooling system of nuclear reactor by large scale vortex generation in nuclear fuel bundle. The large scale vortex motions were generated by rearranging the inclination angles of mixing vanes to the coordinate directions. Axial development of mean and turbulent velocities in the subchannels were measured by the 2-color LDV system. Eddy diffusivity heat flux model and $k-varepsilon$ model were employed to analyze the turbulent heat and fluid flows in the subchannel. The turbulence generated by split mixing vanes has small length scales so that they maintain only about $10 D_H$ after the spacer grid. On the other hand, the turbulences generated by the large scale vortex continue more and remain up to $25 D_H$after the spacer gird.

• 대한치과교정학회지
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• 제15권2호
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• pp.369-376
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• 1985

A 10 year & 11 month old girl patient who had Angle's Class III malocclusion were treated by chin cap and fixed appliances. The treatment results obtained were as to]lows: 1. The anterior crossbite was corrected. 2. The functional overbite & overjet were established. 3. The favorable molar relationships were achieved. 4. The forward growth of the mandible was restrained. 5. The axial inclination of the upper & lower incisors were changed and the upper dental arch length was increased. 6. The facial profile was improved resulting from the good upper & lower jaw relations. 7. There was no harmful changes on the teeth S the periodontal tissues after treatment. 8. The good occlusal stability was showed after 1 year of retention.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.366-373
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• 2002

This paper describes the load distribution and settlement of rockbolted-drilled shafts subjected to axial and lateral loads with the view to shortening the embedded depth of the pile shaft. The emphasis was on quantifying the reinforcing effects of rockbolts placed from the shafts to surrounding weathered rocks based on small-scale model tests peformed on instrumented piles. The major influencing parameters on reinforcing drilled shaft behavior are the number, the positions on the shaft, the grade, and the inclination angle at which the rockbolts are placed. The model tests was 1/40 scaled simulations of the behavior of the drilled shafts with varying combinations of the major influencing parameters. The incremental effects of reinforcement based on the various parameters have been weighed against load transfer characteristics before and after rockbolt installations.

• 한국임상수의학회지
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• 제33권6호
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• pp.340-345
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• 2016

The present study determined the normal reference ranges for the femoral and tibial joint orientation angles of small-breed dogs. For this purpose, 60 each of cadaveric canine femurs and tibias from normal small-breed dogs (Maltese, Poodle, Shih Tzu, Yorkshire Terrier) were examined with radiographs and photographs. Axial and frontal radiographs and photographs of each bone were obtained, from which anteversion and inclination angles, anatomic lateral proximal and distal femoral angles (aLPFA and aLDFA), mechanical lateral proximal and distal femoral angles (mLPFA and mLDFA), and mechanical medial proximal and distal tibial angles (mMPTA and mMDTA) were measured. The 95% CI for radiographic values of all femurs and tibiae were anteversion angle, $23.4-27.4^{\circ}$; inclination angle, $128.4-130.4^{\circ}$; aLPFA, $117.8-122.1^{\circ}$; aLDFA, $93.7-95.2^{\circ}$; mLPFA $113.8-117.3^{\circ}$; mLDFA $99.2-100.5^{\circ}$; mMPTA $96.8-98.5^{\circ}$; mMDTA $89.4-90.7^{\circ}$. The Maltese had a larger anteversion angle than the Poodle and the Yorkshire Terrier and a larger mLPFA than the Poodle. In the comparison between the radiographs and the photographs, significant differences were found in the anteversion angle, mLPFA, mMPTA, and mMDTA. The established normal reference values might be useful for determining whether a valgus or varus deformity of the femur or the tibia is present and if so, the degree of angular correction needed.

• Geomechanics and Engineering
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• 제21권6호
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• pp.571-582
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• 2020

Aiming at the mechanical and structural characteristics of the contact zone composite rock, the uniaxial compression tests and numerical studies were carried out. The interaction forms and formation mechanisms at the contact interfaces of different materials were analyzed to reveal the effect of interaction on the mechanical behavior of composite samples. The research demonstrated that there are three types of interactions between the two materials at the contact interface: constraint parallel to the interface, squeezing perpendicular to the interface, and shear stress on the interface. The interaction is mainly affected by the differences in Poisson's ratio and elastic modulus of the two materials, stronger interface adhesion, and larger interface inclination. The interaction weakens the strength and stiffness of the composite sample, and the magnitude of weakening is positively correlated with the degree of difference in the mechanical properties of the materials. The tensile-shear stress derived from the interaction results in the axial tensile fracture perpendicular to the interface and the interfacial shear facture. Tensile cracks in stronger material will propagation into the weaker material through the bonded interface. The larger inclination angle of the interface enhances the effect of composite tensile/shear failure on the overall sample.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 춘계종합학술대회
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• pp.569-571
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• 2007

본 논문에서는 Ka-대역에서 도파관 형태의 구형 혼, 원형 편파기 및 직선구조 모드변환기가 결합된 혼 안테나의 설계 및 제작에 관하여 서술한다. 원형 편파기는 광대역 특성을 가지는 유전체 타입으로 구형도파관에 $45^{\circ}$ 기울여 삽입하는 구조를 갖으며, 직선구조 모드변환기는 계단식 구조로 동축선으로부터 입력되는 TEM 모드 신호를 도파관의 TE 모드로 변환손실을 최소화 할 수 있도록 설계되었다. 제작된 혼 안테나는 $30.085\sim30.885GHz$에서 동작하며, VSWR < 1.5, Axial ratio < 1.0dB의 특성과 함께, 동작주파수 대역에서 $6.7\sim7.0dBi$의 이득을 갖는다.

• Earthquakes and Structures
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• 제14권3호
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• pp.273-283
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• 2018

Previous experimental researches indicate that reinforced concrete beam-column joints play an important role in the mechanical properties of moment resisting frame structures, so as to require proper design. In order to get better understanding of the beam-column joint performance, a rational model needs to be developed. Based on the former considerations, two typical models for calculating the shear carrying capacity of the beam-column joint including the inelastic reinforced concrete joint model and the softened strut-and-tie model are selected to be introduced and analyzed. After examining the applicability of two typical models mentioned earlier to interior beam-column joints, several adjustments are made to get better predicting of the test results. For the softened strut-and-tie model, four adjustments including modifications of the depth of the diagonal strut, the inclination angle of diagonal compression strut, the smeared stress of mild steel bars embedded in concrete, as well as the softening coefficient are made. While two adjustments for the inelastic reinforced concrete joint model including modifications of the confinement effect due to the column axial load and the correction coefficient for high concrete are made. It has been proved by test data that predicted results by the improved softened strut-and-tie model or the modified inelastic reinforced concrete joint model are consistent with the test data and conservative. Based on the test results, it is also not difficult to find that the improved beam-column joint model can be used to predict the joint carrying capacity and cracks development with sufficient accuracy.

• 대한기계학회논문집B
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• 제25권2호
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• pp.225-234
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• 2001

This paper represents the vector fields, three dimensional mean velocities, the turbulent intensities, the turbulent kinetic energy, and the Reynolds shear stresses in the X-Y plane of gas swirl burner with a cone type baffle plate measured by using X-probe from hot-wire anemometer system. This experiment is carried out at flow rates 350 and 450ℓ/min respectively, which are equivalent to the combustion air flow rate necessary for heat release 15,000 kcal/hr in gas furnace, in the test section of subsonic wind tunnel. The vector plot shows that the maximum axial mean velocity component exists in the narrow slits situated radially on the edge of gas swirl burner, for that reason, there is some entrainment phenomena of ambient air in the outer region of burner. Moreover, mean velocities in the initial region are largely distributed near the outer region of burner at Y/R≒0.97, but they diffuse and develop into the center flow region of burner according to the increase of axial distance. The turbulent intensities and the turbulent kinetic energy due to large inclination of mean velocity and swirl effect show that the maximum value in the initial region of burner is formed in the narrow slits situated radially on the edge of gas swirl burner and large values are mainly formed in the entire region of burner after X/R=2.4358, hence, the combustion reaction is anticipated to occur actively near this region. And the Reynolds shear stresses are also largely distributed from slite to vanes of gas swirl burner in the intial region, but their values largely disappear after X/R=3.2052.

• Journal of applied mathematics & informatics
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• 제41권1호
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• pp.51-70
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• 2023

The flow of an incompressible Ellis fluid in an inclined asymmetric channel, driven by peristaltic waves was studied under low Reynolds number and long wavelength assumptions. The wave on each side of the channel are assumed to be an infinite train of sinusoidal waves, both having the same constant wave speed and wavelength however, they vary in wave amplitude, channel half width and phase angle. We derived expressions for the axial and transverse velocities, volume flow rate, pressure rise per unit wavelength and streamlines. The effects of varying the wave amplitudes, the phase angle, the channel width, the angle of inclination of the channel as well as the fluid parameters on the flow were analyzed. Trapping conditions were determined and the presence of reflux highlighted using the streamlines for the necessary channel and fluid conditions. By varying the fluid parameters, changes in the fluid that deviated from the Newtonian case resulted in a reduction in the axial velocity in the neighborhood of the center of the channel and a simultaneous increase in the velocity at the periphery of the channel. A nonlinear relation was observed with the pressure rise and the volume flow rate. This nonlinear relation is more pronounced with an increase in the absolute value of the volume flow rate. For Newtonian fluids a linear relation exists between these two variables. The fluid parameters had little effects on the streamlines. However, variations of the wave amplitudes, volume flow, channel width and phase angle had greater effects on the streamlines and hence the trapped region.