• Bulletin of the Society of Naval Architects of Korea
• /
• v.4 no.1
• /
• pp.49-54
• /
• 1967

The authors considered the effects of trim in the small coastal passenger boat upon resistance in this paper. Any change of trim no matter how small, necessarily produces some effect upon resistance. The relations between the resistance coefficients and trim were investigated through the towing test of the Model $MCI-P_1-65$, Korean Standardized Ship, GT 70 tons passenger boat in the gravitational tank. The Lines of the Model are given in Fig. 1. Principal dimensions and other characteristics vary with the trim in general. Those values varied with the trim for $MCI-P_1-65$ are tabulated in table 1. The resistance was measured at five conditions such as even keel, 0.0273L, (original designed trim) 0.0473L, 0.0663L, 0.0873L trim by the stern, fixing the displacement corresponding to the designed load water line. Model was made of wood in length of 3.5 feet coated with varnish, and without appendages. As the artificial turbulent stimulator, the sand strip method was used. The results of model towing tests, correcting to water temperature of $70^{\circ}F$, were expanded to full scale using the Schoenherr's friction formula and surface roughness allowance coefficient of 0.0004. The authors point out, the following results. 1) Optimum trim which gives the minimum resistance exists for every speed at constant displacement and each comes to the same value. For $MCI-P_1-65$ optimum trim is 0.0673L trim by the stern(Fig.4-The cross curves of the resistancecoefficients). 2) At constant displacement, when LCB(longitudinal position of center of buoyancy) varies with the trim, there exists optimum value of LCB which gives minimum resistance for every speed and each comes to the same value. For $MCI-P_1-65$ optimum position of LCB is 8%L aft from midship section (Fig.6).

• Hwankyungkyoyuk
• /
• v.14 no.2
• /
• pp.15-27
• /
• 2001

The purpose of this study is to understand and compare the characteristics of the content organization system of three Environment textbooks currently used, and to examine its connectivity with the teaching & teaming methods included in the Environment subject part of the 7th Korean National Curriculum. For the analysis three Environment textbooks for middle school and their teacher's guide books by three companies. published(A, B, and C) The result of the taxonomic analysis showed that three Environment books had different steps to get to the lesson class unit in the way that A of six steps, B of five steps and C of seven steps. The amount of main text was different In the domains of'Human and Environment','Environmental Problems and its Counter-plan'and'Environmental Conservation'of three textbooks each. All of three textbooks had the biggest percentage in sub-domains of'Living Environment to Keep'and'Global Environmental Problem'in 'Environmental Problems and its Counter-plan'domain. Considering teaching & loaming methods all of three textbooks contained many activities as 55 in A, 66 in H and 91 in C. Among 9 teaching 8E teaming methods and others listed in the Environment subject part of the 7th Korean National Curriculum, the investigation method is most frequently used in all of three textbooks. The drama, the paly and the case study were used rarely as teaching & teaming methods in activities In the consideration of the content amount regarding academic fields, it was revealed that three textbooks overemphasized the aspect of natural sciences comparing the aspect of human & social sciences aspect as a whole. Generally the appendix section of all three textbooks were well organized to support the teaching and teaming activities in main text.

• Journal of Welding and Joining
• /
• v.27 no.3
• /
• pp.73-79
• /
• 2009

This present paper investigated the mechanical properties and the microstructures of each penetration shapes classifying the conduction shape area and the keyhole shape area about electron beam welded 120(T)mm thick plated aluminum 5052 112H. As a result the penetration depth is increased linearly according to the output power, but the aspect ratio is decreased after the regular output power. In the conduction shape area, the Heat affected zone is observed relatively wider than the keyhole shape area. In the material front surface of the welded specimen, the width is decreased but the width in the material rear surface is increased. After the measuring the Micro Vikers Hardness, it showed almost similar hardness range in all parts, and after testing the tensile strength, the ultimate tensile strength is similar to the ultimate tensile strength of the base material in all the specimens, also the fracture point was generated in the base materials of all the samples. In the result of the impact test, impact absorbed energy of the Keyhole shape area is turned up very high, and also shown up the effect about four times of fracture toughness comparing the base material. In the last result of observing the fractographs, typical ductile fraction is shown in each weld metal, and in the basic material, the dimple fraction is shown. The weld metals are shown that there are no other developments of any new chemical compound during the fastness melting and solidification.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.26 no.5
• /
• pp.481-489
• /
• 2000

This research was focused on overall examination of tissue alteration, wound healing promotion. After the hair on the dorsal surface was shaved, $5{\times}5mm$ oval skin defect was formed. Experimental wounds of right side were irradiated on every day for 90 second with Ga-Al-As semi-conductor laser. Left side wounds served as control group. The rats were sacrificed on the 1st, 3rd, 5th, 7th, 14th, 21th day. For light microscopically, parafin section were stained with H&E, MT. The outcomes were as follows : 1. On 1st day, experimental and control group were seen acute inflammatory cell infiltration, edema. 2. On the 3rd days, both groups were seen crust development, collagen, blood vessel proliferation. 3. On the 5th days, experimental group were reduced edema and inflammatory cell infiltration than control group. 4. On the 7th days, both groups were observed edema, inflammatory cell infiltration disappearance and keratinocytes motility from wound defect. 5. On the 14th days, experimental group appeared collagen, blood vessel proliferation and hair follicle than control group. 6. On the 21th days, both groups were seen normal status re-epithelization. According to the above results, The wound-healing stimulated by laser radiation involves an increased rate of epithelial growth. LLLT was confirmed that it has fibroblast, blood vessel proliferation, influence initial wound healing process.

• Transactions of Materials Processing
• /
• v.23 no.8
• /
• pp.489-494
• /
• 2014

Micro forming is an appropriate process to manufacture very small metal parts which can be employed in the field of electronic devices or electrically controlled mechanical systems. The purpose of the current study was to investigate the influences of both blankholding force and blank diameter for the deep drawing of very small cups. It is essential to control the blankholding force because improper force can result in defects such as wrinkles in the flange or cracks in the corner of the drawn cups. In the current study blankholding force was controlled by springs connected to the blankholder of a press die. Exchangeable bushing dies with various die-corner radii were also used. To obtain the limit drawing ratio for each working condition several sizes of circular specimens were prepared using blanking tools. Beryllium copper(C1720) alloy sheet of $50{\mu}m$ thickness was chosen for the experiments. The maximum limit drawing ratio of 2.1 was achieved experimentally for the conditions of the blankholder force(BHF)=5.3kgf and Rd=0.3mm. Both thickness and hardness along the central section of drawn cups were measured and compared for different drawing conditions. It was found that the deviation of measured data in the thickness and hardness distribution increases with increasing blankholder force and blank diameter.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• v.3 no.3
• /
• pp.189-196
• /
• 1999

The community structure, phytomass, and primary productivity in Thuja orientalis stands on a limestone area located in Maepo-up, Chungbuk province in Korea were estimated quantitatively. Seven species including a small proportion of Quercus dentata were identified in the tree layer, 26 species including Ulmus macrocarpa in the shrub layer, and 79 species including Carex lnceolata in the herb layer of the Thuja stands. The vertical distribution of the fine root phytomass exhibited a power functional decrease relative to the soil depth. The seasonal changes in the fine root phytomass at a soil depth of 5 cm were closely related to the pecipitation in the study area. The productivity of the stand of stems, branches, leaves, and roots were 10.72, 0.82, 0.45 and 6.46 ton DM. $ha^{-1}$ .$yr^{-1}$, respectively. The Thuja stand had a high foliage(25%) and low rate of production per unit of foliage. The annual turnover rate of the fine roots int he Thuja stand was 6.71 $yr^{-1}$. The net primary production of the overstory including the understory was estimated at 19.48 ton DM.$ha^{-1}$.$yr^{-1}$ including an underground section of 6.46 ton DM.$ha^{-1}$.$yr^{-1}$(33%). The allocation ratio of net production to root was lower in the limestone Thuja communities than at the nearby non-limestone ones, whereas the production efficiency to leaf weight was higher in the limestone communities. These results would seem to indicate that the limited production capacity is due to the calcium toxicity and low availability of iron and phosphorus in a limestone soil with a high pH, calcium, and bicarbonate content with a strategy for survival in a hostile habitat.

• Research in Community and Public Health Nursing
• /
• v.1 no.1
• /
• pp.115-128
• /
• 1989

The purpose of this survey was to measure the health service activity of the Public health nurses and analyze the related factors influencing to their activities. The subjects of this study were 249 PHN in Health Centers, Pusan and Kyung Nam area and survey was conducted from 5th, January to 28th, February, 1987. The results of this study were as follow; 1. Total performance average of health service activities was 2.52. Among the 1 t health categories, health service planning (3.05) was the most and others health care (2.07) was the least active. 2. In performed degree of activities in department of Health Center. The hightest performed activities were T.B care in T.B clinic (3.79), family planning in family planning clinic (3.94), screening for disease in medical office (3.42), prenatal care in M.C.H. room (3.46) work planning in injection room (3.76), postpartum care in MCH center (3.63). 3. There were significient difference in age, education, religion, section of service, duty between the general characteristics and health service activities.(p<.05).

• Journal of Korean Association for Spatial Structures
• /
• v.12 no.3
• /
• pp.63-70
• /
• 2012

In this study, the displacement-based design concept, the performance by the existing reinforced concerte column and steel reinforced concrete composite column for SRC purchased the maximum design ground acceleration improvement compared to the performance design. SRC have several advantages such as strength enhancement and high ductility. H-beam or steel tubes were used for embedded elements of the SRC composite columns. SRC cross-section for the P-M diagram and analysis on the nominal bending monent SRC designed for composite columns for disparity estimation is presented to the displacement-based seismic design. Performance improvement of the performance-based design performance targets for the design seismic displacement and design criteria for the direct displacement-based design methods and to improve the seismic performance due to the displacement coefficient method is proposed to design. SRC compared with the RC column designed to improve the performance and displacement ductility ratio displacement results in the performance design results showed significantly improved performance.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.4
• /
• pp.551-561
• /
• 1998

This paper was studied to understand the characteristics of heat transfer coefficients and surface temperature distributions around a circular combustion chamber within the heat-intercept duct of kerosene fan heater. The experiment was carried out in the heat-intercept duct of kerosene fan heater attached to the blow-down-type subsonic wind tunnel with a test section of 240 mm * 240 mm * 1200 mm. The purpose of this paper was to obtain the basic data related with normal combustion for new design from conventional kerosene fan heater, and to investigate the effect of surface temperature, local and mean heat transfer coefficients versus flow-rate of convection axial fan according to the variations of heat release conditions from kerosene fan heater during normal combustion. Consequently it was found that (i) the revolution of convection axial fan during combustion had a smaller value than that of non-combustion because of the thermal resistance due to the high temperature in the heat-intercept duct, (ii) the pressure ratio P$_{2}$/P$_{1}$ had a comparatively constant value of 0.844 according to the revolution increase of turbo fan and the heating performance of kerosene fan heater had a range of 1,494 ~ 3,852 kcal/hr, (iii) the local heat transfer coefficient around a circular combustion chamber had a comparatively larger scale in the range of 315 deg. < .theta. < 45 deg. than that in the range of 90 deg. < .theta. < 270 deg. as a result of heat transfer difference between front and back of a circular combustion chamber, and (iv) the mean heat transfer coefficient around a circular combustion chamber increased linearly like a H$_{m}$=95.196Q+104.019 in condition of high heat release according to the increase of flow-rate of axial fan.n.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.9
• /
• pp.1032-1038
• /
• 2014

In this study, an experimental study was performed to understand the boiling heat transfer characteristics of FC-72 in parallel micro-channels. The parallel micro-channels contained channels having a $0.2mm{\times}0.45mm$ [$H{\times}W$] cross section and length of 60 mm. And heat flux was varied from 16.4 to $25.6kW/m^2$ and mass fluxes from 300 to $500kg/m^2s$. The measured heat transfer coefficient was sharply decreased at lower vapor quality and then it was kept approximately constant as the vapor quality is increased. From the experimental results, the boiling heat transfer mechanism of FC-72 was confirmed and the measured heat transfer coefficient was compared and analyzed with the existing correlations to predict the heat transfer coefficient.