• 대한지역사회영양학회지
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• 제17권6호
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• pp.752-771
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• 2012

This study was conducted to investigate the effect of sodium reduction education program of a public health center on the blood pressure, blood biochemical profile and sodium intake of hypertensive adults. The program continued for 16 weeks with an 8-week nutrition education and an 8-week follow-up to forty two subjects, 6 males and 36 females aged 46 to 80 years. Subjects received nutrition education including lectures, activities, cooking classes and nutrition counseling. Physical fitness, management of stress, and nutrition counseling were provided during the follow-up. The program was evaluated three times, before and after the nutrition education, and after the follow-up. Systolic blood pressure (p < 0.0001) and diastolic blood pressure (p < 0.001) were decreased after completion of the program. Body weight (p < 0.005), percent body fat (p < 0.005) and body mass index (p < 0.001) were decreased, too. There were no significant differences in blood glucose, HDL-cholesterol and triglycerides, while elevated levels of total cholesterol (p < 0.001) and LDL-cholesterol (p < 0.001) appeared after the program completion. Decreased intakes of vitamin A (p < 0.05), ${\beta}$-carotene (p < 0.001) and sodium (p < 0.001) were observed. Consumption frequency of noodles, soups, stews, kimchi, fishes/shellfish, seasoned vegetables, and salted seafoods/pickles (p < 0.05~p < 0.001) were decreased, while that of all food groups were not changed during the follow-up. Total score of nutrition knowledge related to sodium intake and hypertension (p < 0.001), and that of dietary behavior associated with high sodium intakes were changed positively (p < 0.001) only during the nutrition education. This sodium reduction education program, including the follow-up study showed positive effects on the blood pressure, sodium intake, nutrition knowledge and dietary behavior of hypertensive adults.

• Tribology and Lubricants
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• 제39권4호
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• pp.154-166
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• 2023

This study establishes a numerical analysis model of the finite element overhung rotor supported by a DTRB and describes the stiffness properties of the DTRB. The vibration characteristics and contact pressure of the RBR system are predicted according to the DTRB support characteristics such as the initial axial compression and roller profile. The stiffness of the DTRB significantly varies depending on the initial axial compression and external load owing to the occurrence of rollers under the no-load condition and increase in the Hertz contact force. The increase in the initial axial compression increases the rigidity of the DTRB, thereby reducing the displacement of the RBR system and simultaneously increasing the natural frequency. However, above a certain initial axial compression, the effect becomes insignificant, and an excessive increase in the initial axial compression increases the contact pressure. The roller crowning radius, which gives a curvature in the longitudinal direction of the roller, decreases the displacement of the RBR system and increases the natural frequency as the value increases. However, an increase in the crowning radius increases the edge stress, causing a negative effect in terms of the contact pressure. These results show that the DTRB support characteristics required for reducing the vibration and contact pressure of the RBR system supported by the DTRB can be designed.

• 소성∙가공
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• 제3권1호
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• pp.97-109
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• 1994

Closed-die forging of the spur gears with circular are fillet has been analyses by using the upper-bound method. A kinematically admissible velocity field has been developed, wherein, the tooth profile consists of the involute curve and the circular arc fillet. In the analysis, the deformation regions have been divided into eight zones. A constant frictional stress has been assumed on the contacting surfaces Utilizing the formulated velocity field, numerical calculations have been carried out to investigate the effects of various parameters, such as module, number of teeth, addendum modification coefficient and friction factor, on the relative forging pressure of spur gears. As the result of numerical calculations, the relative forging pressure does not change so much against the variation of module. On the other hand, the relative forging pressure increases at the final filling stage as the addendum modification coefficient increases.

• 항공우주기술
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• 제2권2호
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• pp.133-141
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• 2003

초소성 공정을 이용하여 구형 압력용기를 제작하는 경우 두께와 구형의 형상은 일정하지 않고 성형공정이 진행함에 따라 변하게 된다. 본 연구에서는 공정과정 동안 발생하는 초기 블랭크의 두께변화 예측을 이론적으로 해석하였다. 두께변화 예측을 위한 이론적인 모델은 Kuglov 등이 적용한 박막이론을 사용하였으며 요구되는 최종 두께를 얻기 위한 초기 블랭크의 두께, 블랭크의 균일한 변형을 얻기 위한 시간에 따른 압력 프로파일, 각 성형단계에서 위치에 따른 두께분포 및 시간에 따른 두께분포를 결정하였다. 공정 단계 전반에 걸쳐서 적용 모델 및 해석 프로그램의 적합성을 문헌의 시험 결과와 비교하여 검증하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제11권3호
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• pp.53-60
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• 1987

Steam ejector is a equipment which compresses the gases to desired discharge pressure. It is widely used for the evacuation systems because of its high working confidence. And recently it is used as the thermo-compressors in the various energy saving systems. Steam ejector is constructed of three basic parts; a suction chamber, a motive nozzle and a diffuser. The high velocity stream jet of steam emitted by the motive nozzle creats suction chamber, which draws the low pressure gases. The diffuser converts the kinetic energy of high velocity flow to pressure energy. It is not easy to determine the dimensions of a steam ejector met to the desired design condition, because that the expected suction rates must be obtained by reapeating the complicate calculation. And also such a calculation is concomitant with geometrical analysis for suction part and diffuser based on the stability of steam flow. Therefore, it is considered that the Computer-Aided Design (CAD) of steam ejector is a powerful design method. In this paper, computer program for steam ejector design is developed based on the theoretical research and the previous experimental results. And the determinating method of diffuser inlet angle and the velocity development profile of suction gas along to the diffuser are suggested. The validity of the development profile of suction gas along to the diffuser are suggested. The validity of the developed computer results with other's for the practical design calculation of a manufactured steam ejector.

• Tribology and Lubricants
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• 제23권5호
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• pp.187-194
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• 2007

The profile of the roller in the axial direction is the main design factor in order to increase endurance life against the contact fatigue due to the stress concentration along the edge of the roller. Even under the elas-tohydrodynamic lubrication (ehl) conditions, the stress concentration along the edge of the roller greatly worsens the fatigue life both for the roller and contacting body. In this study, roller contacts of finite axial length are studied for the film thickness and pressure of ehl. For the real contact behaviors under the ehl conditions, multigrid and multi-level method is applied so that much higher loading conditions can be investigated. Several axial profiles of roller are investigated to verify how both ehl film and pressure are generated and some of them are recommended for the ehl contact condition.

• 대한치과기공학회지
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• 제45권3호
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• pp.81-86
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• 2023

Purpose: This study aimed to observe the effect of laminate veneer on patient's teeth based on the manufacturing of laminate veneer restorations, which are produced by fabricating a ceramic cast body using IPS Empress, a pressure casting method and then forming the veneer by layering. Subsequently, we assessed the potential of its clinical application. Methods: This study discusses and preserves various treatment plans, such as diagnostic wax-up and treatment room diagnosis, for patients who visit the hospital to improve the appearance of teeth due to diastema of maxillary teeth, inexperienced resin filling, lack of esthetics, and external teeth. A ceramic cast body is constructed using IPS Empress, which is an effective and aesthetic restoration pressure casting method to restore the veneer with a laminate made by layering. Results: Compared with the preoperative state, the frontal view of the patient after the final restoration showed the formation of a natural smile line; the space between the central and lateral incisors was filled in synchronously with the adjacent teeth. In addition, the emergence profile is maintained by reducing the over-contour as much as possible. Conclusion: The patient's quality of life is improved by providing them with a satisfactory natural smile.

• 한국정밀공학회지
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• 제23권9호
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• pp.54-60
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• 2006

Fitting process carried out in automobile transmission assembly line is classified into three classes; heat fitting, press fitting, and their combined fitting. Heat fitting is a method that heats gear to a suitable range under the tempering temperature and squeezes it toward the outer diameter of shaft. Its stress depends on the yield strength of gear. Press fitting is a method that generally squeezes gear toward that of shaft at room temperature by press. Another method heats warmly gear and safely squeezes it toward that of shaft. Warm shrink fitting process for automobile transmission part is now gradually increased, but the parts (shaft/gear) assembled by this process produced dimensional changes of gear profile in both radial and circumferential directions. So that it may cause noise and vibration between gears. In order to solve these problems, we need an analysis of warm shrink fitting process, in which design parameters are involved; contact pressure according to fitting interference between outer diameter of shaft and inner diameter of gear, fitting temperature, and profile tolerance of gear. In this study, an closed form equation to predict contact pressure and fitting load was proposed in order to develop optimization technique of warm shrink fitting process and verified its reliability through the experimental results measured in the field and FEM, that is, thermal-structural coupled field analysis. Actual loads measured in the field have a good agreement with the results obtained by theoretical and finite element analysis and also the expanded amounts of the gear profile in both radial and circumferential directions are within the limit tolerances used in the field.

• 한국연소학회:학술대회논문집
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• 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
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• pp.103-108
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• 2003

The effect of equivalence ratio and fuel/air mixing quality on the phase-resolved gas temperatures at different phases of the oscillating pressure cycle was experimentally investigated. An atmospheric pressure, optically accessible and laboratory-scale dump combustor operating on methane with heat release rate of 1.59kW was used. Temperature measurements were made using coherent anti-Stokes Raman spectroscopy (CARS) at several spatial locations for typical unstable combustion conditions. Analysis was conducted using parameters such as phase-resolved averaged temperature, normalized standard deviation and temperature probability distribution functions (PDFs). Also the probability on the occurrence of high temperature (over 1900K) was investigated to get the information on the perturbation of equivalence ratio and NOx emission characteristics. It was shown that most of temperature histograms exhibit Gaussian profile which has short breadth of temperature fluctuation at equivalence ratio of 0.6, while beta profile was predominant for the cases of other equivalence ratios (${\Phi}$=0.55, 0.50). The characteristics on the occurrence of high temperature also displayed periodic wave form which is very similar to the pressure signal. And the amplitude of this profile goes larger as the fuel/air mixing quality become poorer. These also provided additional information on the perturbation of equivalence ratio at flame as well as NOx emission characteristics.

• International Journal of Fluid Machinery and Systems
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• 제3권1호
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• pp.20-28
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• 2010

This paper deals with the Design and Analysis of a Controlled Diffusion Aerofoil (CDA) Blade Section for an Axial Compressor Stator and Effect of incidence angle and Mach No. on Performance of CDA. CD blade section has been designed at Axial Flow Compressor Research Lab, Propulsion Division of National Aerospace Laboratories (NAL), Bangalore, as per geometric procedure specified in the U.S. patent (4). The CFD analysis has been performed by a 2-D Euler code (Denton's code), which gives surface Mach No. distribution on the profiles. Boundary layer computations were performed by a 2-D boundary layer code (NALSOF0801) available in the SOFFTS library of NAL. The effect of variation of Mach no. was performed using fluent. The surface Mach no. distribution on the CD profile clearly indicates lower peak Mach no. than MCA profile. Further, boundary layer parameters on CD aerofoil at respective incidences have lower values than corresponding MCA blade profile. Total pressure loss on CD aerofoil for the same incidence range is lower than MCA blade profile.