• Journal of Preventive Medicine and Public Health
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• v.1 no.1
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• pp.79-86
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• 1968

This paper describes the incidence and some epidemiological features of drowning accident out of a series of our study on the epidemiology of various accidents in Korea. By the daily press it is apparent from the frequent reporting of swimming accidents that the incidence would be high. In the rural areas, there are, at present, about 1,250 artificial lakes and farm ponds to be utlized for rice production. The reservoirs, irrigation ditches and riversides are also used for recreation. In most places facilities for aquatic activities is meager, and safety measures for the prevention of drowning is not sufficiently enforced. In the survey crude data on drownings were collected from the concerned governmental statistic books for the period 1955 to 1967 which were compiled not in a uniform way. Drownings were classfied into two categories, one is accidental drowning, E 929 and the other is due to cataclysm, E 934, according to the WHO international classification of diseases. Epidemiological variables in relation to drowning accident were obtained through qualitative analysis of informations from the popular news papers. The following summary may be drawn; 1. The average number of deaths due to accidental drowning totaled 1,088 annually and the mortality rate per 100,000 population was 3.4, The 42.0% of all drownings were rescued and the remaining were not saved. 2. The sex ratio (M/F) of the victims for all ages was 5 to 1, which had a wide range of difference among the age groups. The young ages less than 20 years occupied 68.0% of all deaths. 3. The percentage distribution of the causes of accidents revealed 31.9% for careless swimming, 45.5% for unskilled, 10.6% for swimmer's cramp and 6.0% for drunked. The distribution of places where accidents occurred showed 88.0% for rivers, water reservoirs, irrigation ditches and 12.0% for regular swimming pools. The seasonal distribution of cases indicated 85.0% of the total were seen during the summer months, June-August, and 50.0% of them occurred on Sundays, 4. The average annual deaths due to cataclysm were 402 and mortality rate per 100,000 population was 1.6, but the number of victims due to cataclysm varied greatly each year. 5. The accident cases due to cataclysm were classified into 60.0% for injuries, 40.0% for deaths. The 26.8% of all deaths were missing cases. 6. The deaths due to either accidental drowning or cataclysm totaled 1,490, and the death rate per 100,000 for the whole country was 5.0.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.120-120
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• 1998

Boron nitride (BN) films have attracted a growing interest for a variety of t technological applications due to their excellent characteristics, namely hardness, c chemical inertness, and dielectrical behavior, etc. There are two crystalline phases 1551; of BN that are analogous to phases of carbon. Hexagonal boron nitride (h-BN) has a a layered s$\sigma$ucture which is spz-bonded structure similar to that of graphite, and is t the stable ordered phase at ambient conditions. Cubic boron nitride (c-BN) has a z zinc blende structure with sp3-bonding like as diamond, 따ld is the metastable phase a at ambient conditions. Among of their prototypes, especially 삼Ie c-BN is an i interesting material because it has almost the same hardness and thermal c conductivity as di없nond. C Conventionally, significant progress has been made in the experimental t techniques for synthesizing BN films using various of the physical vapor deposition 밍ld chemical vapor deposition. But, the major disadvantage of c-BN films is that t they are much more difficult to synthesize than h-BN films due to its narrow s stability phase region, high compression stress, and problem of nitrogen source c control. Recent studies of the metalorganic chemical vapor deposition (MOCVD) of I III - V compound have established that a molecular level understanding of the d deposition process is mandatory in controlling the selectivity parameters. This led t to the concept of using a single source organometallic precursor, having the c constituent elements in stoichiometric ratio, for MOCVD growth of 삼Ie required b binary compound. I In this study, therefore, we have been carried out the growth of h-BN thin f films on silicon substrates using a single source precursors. Polycrystalline h-BN t thin films were deposited on silicon in the temperature range of $\alpha$)() - 900 $^{\circ}$C from t the organometallic precursors of Boron-Triethylamine complex, (CZHs)3N:BRJ, and T Tris(dimethylamino)Borane, [CH3}zNhB, by supersonic molecular jet and remote p plasma assisted MOCVD. Hydrogen was used as carrier gas, and additional nitrogen w was supplied by either aDlIDonia through a nozzle, or nitrogen via a remote plasma. T The as-grown films were characterized by Fourier transform infrared spectroscopy, x x-ray pthotoelectron spectroscopy, Auger electron spectroscopy, x-ray diffraction, t transmission electron diffraction, optical transmission, and atomic force microscopy.roscopy.

• Food Science of Animal Resources
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• v.27 no.1
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• pp.67-72
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• 2007

We investigated the effects feeding illite on growth performance and meat quality characteristics in finishing pigs. Forty-eight pigs ($Landrace{\times}Yorkshire{\times}Duroc$; $68.3{\pm}1.6 kg$ average initial body weight) were used in a 50 day experiment. Pigs were randomly placed into one of four experimented diet groups (0, 0.2, 0.5 and 1% illite) and were slaughtered at approximately 110 kg live weight. Although there were no significantly differences in daily weight gain, feed intake and feed conversion between controls and groups fed illite, those values were increased as increasing of illite concentration in feed. Carcass weight, carcass ratio and backfat thickness were not affected by dietary illite supplementation. However, the percentage of A grade carcasses were significantly increased by dietary supplement of 1.0% illite. There were no significantly differences in moisture, crude protein and crude ash between controls and groups fed illite, but the crude fat of 1.0% illite supplemented groups was significantly lower than other groups (p<0.05). All muscles from control and treatment groups had normal pH 5.55-5.68. However, lightness ($L^*$) values of pork decreased as increasing illite supplement. Whereas red-ness ($a^*$) and yellowness ($b^*$) values were not significantly changed. In fatty acid composition, palmitoleic acid and linoleic acid were significantly higher in 1.0% illite dietary group, saturated fatty acid was decreased and unsaturated fatty acid was increased by 0.5-1.0% illite supplementation.

• Journal of fish pathology
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• v.15 no.1
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• pp.25-35
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• 2002

Effects of medicinal herb extract on nonspecific immune responses, hematology and disease resistance against Edwardsiella tarda in olive flounder, Paralichthys olivaceus were evaluated. Wormwood, Artemisia asiatica NAKAI and barrenwort, Epimedium koreanum NAKAI were mixed at a ratio of 7 : 3 (w/w) for 2-herbs extract and wormwood, barrenwort, Korean forsythia, Forsythia koreana NAKAI, chrysanthemum, Chrysanthemum zawadskii var. latilobum KITAMURA, peppermint, Mentha arvensis L. var, piperascens MALINV., great burnet, Snaguisorba afficinalis L., Lizard tail. Saururus chinensis BAILL., mulberry, Morus alba L., and star anise, Illicium varum HOOK, f, at the same weight for 9-herbs extract. Two-herbs of 9-herbs extract were prepared by heating after adding 10㎖ of distilled water per g of the herb mixtures. Fish (10.3$\pm$2.5g) were fed the experimental diets supplemented with the 2-herbs or 9-herbs extract at the different concentrations of 0%, 0.1%, 0.5% and 1% per kg diet for 12 weeks. Lysozyme and bactericidal activities of serum, and hematological characteristics were examined during experimental period. After feeding test period, all experimental groups were challenged with E. tarda. Lysozyme activity from the fish fed the diet supplemented with 0.1% or 0.5% of 2-herbs extract was significantly higher than the control. But there was no difference both in bactericidal activity and hematology among each group. Sixty seven % of relative percent survival values (RPS) in the group fed the diet supplemented with 0.1% of 2-herbs was higher than the other group and the control. These results suggest that supplenmentation of 0.1% of 2-herbs extract to a commercial diet may enhance disease resistance in olive flounder. Although both 0.1% and 0.5% 9-herbs extract did not improve non-specific immune reponses, they could enhance disease resistance of 53% RPS, respectively.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.3
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• pp.45-52
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• 1992

The Mathematical Model, which can describe the maneuvering motion of a ship in low speed, is highly required these days because it is directly related to the safety of ship in confused harbour. Kose has presented a new model for the low speed maneuvering motion, but the usefulness of it is not confirmed widely. Lets of difficulties are revealed in the case of low speed maneuver, The first is the fact that a ship moves the stirred water region for the longer time than in the case of high speed. So, the hydrodynamic forces, exerted on the hull need to be treated strictly, not by the ordinary differential equation with constant coefficients. Another difficulty is arised from the fact the lateral motion is relatively large comparing to the longitudinal motion in low speed. And, by the result the effect of cross-flow drag or vortex sheding effects are dominant. Besides, the captive model tests of low speed motion has lots of problems. For example, the hydrodynamic forces do not converge to a certain values for the long time. And the absolute values of measured forces are very small, so we must expend lots of efforts to raise up the S/N ratio of the experiments. In this paper, a new mathematical model for the maneuvering motion in low speed, is built up, and the usefulness is discussed, comparing with other models, for example, Kose's model or M.M.G. model or Cross-Flow model, The CMT data for a PCC model of 3.00 M length, released from the RR-742 of Japan, are used for the validation of each models.

• Membrane Journal
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• v.16 no.3
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• pp.221-229
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• 2006

This study is about the preparation and characterization of sulfonated random copolymer membranes containing perfluorocyclobutane (PFCB), fluorenyl, and sulfonyl units. The polymers were prepared through three synthetic steps, that is, the synthesis of a trofluorovinylether-terminated monomer, its thermal polymerization, and post-sulfonation using chlorosulfonic acid. A series of sulfonated random copolymers with different ion exchange capacity (IEC) were prepared by changing contents of fluorenyl uints in polymers with fixed molar ratio of chlorosulfonic acid during the post-sulfonation reaction. All the synthesized compounds were characterized by FT-lR, $^1H-NMR$, $^{19}F-NMR$, and Mass spectroscopy. As the content of sulfonated fluorenyl units increased, the IEC, water uptake, and ion conductivity of the sulfonated random copolymer membranes increased. The sulfonated random copolymer S-1 and S-2 showed higher values of ion conductivity than the Nafion-115 in a wide range of temperatures ($25{\sim}80^{\circ}C$).

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.433-433
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• 2012

As the requirement in patterning geometry continuously shrinks down, the termination of etch process at the exact time became crucial for the success in nano patterning technology. By virtue of real-time optical emission spectroscopy (OES), etch end point detection (EPD) technique continuously develops; however, it also faced with difficulty in low open ratio etching, typically in self aligned contact (SAC) and one cylinder contact (OCS), because of very small amount of optical emission from by-product gas species in the bulk plasma glow discharge. In developing etching process, one may observe that coupon test is being performed. It consumes costs and time for preparing the patterned sample wafers every test in priority, so the coupon wafer test instead of the whole patterned wafer is beneficial for testing and developing etch process condition. We also can observe that etch open area is varied with the number of coupons on a dummy wafer. However, this can be a misleading in OES study. If the coupon wafer test are monitored using OES, we can conjecture the endpoint by experienced method, but considering by data, the materials for residual area by being etched open area are needed to consider. In this research, we compare and analysis the OES data for coupon wafer test results for monitoring about the conditions that the areas except the patterns on the coupon wafers for real-time process monitoring. In this research, we compared two cases, first one is etching the coupon wafers attached on the carrier wafer that is covered by the photoresist, and other case is etching the coupon wafers on the chuck. For comparing the emission intensity, we chose the four chemical species (SiF2, N2, CO, CN), and for comparing the etched profile, measured by scanning electron microscope (SEM). In addition, we adopted the Dynamic Time Warping (DTW) algorithm for analyzing the chose OES data patterns, and analysis the covariance and coefficient for statistical method. After the result, coupon wafers are over-etched for without carrier wafer groups, while with carrier wafer groups are under-etched. And the CN emission intensity has significant difference compare with OES raw data. Based on these results, it necessary to reasonable analysis of the OES data to adopt the pre-data processing and algorithms, and the result will influence the reliability for relation of coupon wafer test and whole wafer test.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.11a
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• pp.29-29
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• 2002

공구강 등 산업용 재료로 널리 사용되는 카바이드 계 재료는 입자 크기 및 분포에 따라 기계적 성질이 변화하므로, 이를 제어하고 조절하는 기술에 관하여 많은 연구가 진행되어 왔다. 본 연구에서는 TiCN-WC-Co 복합초경계 에서 소결 공정 및 조성변화에 따른 입자 모양을 관찰하고 이에 따른 업자 성장 거동을 고찰하였다. 일반적으로 입자 조대화 양상과 고상 입자의 모양과는 밀접한 관계가 있다. 각진 입자의 경우에 는 계면이 원자적으로 singular 하여 원자의 홉착이 어렵기 때문에 임계값 이상의 성장 구동력을 받 는 몇몇 입자만 성장하는 비정상 입자 성장이 일어날 수 있다. 반면에 계면이 rough한 퉁큰 엽자의 경우에는 원자 홉착에 필요한 구동력이 존재하지 않아 성장 구동력을 받는 모든 입자들이 성장하기 때문에 정상 입자 성장을 하게 된다. 이와 같이 입자 모양에 따른 입자 성장 거동은 전체 미세구조를 결정하게 되며, 이에 따른 물리 화학적 물성을 변화시킨다. 이러한 입자 성장 원리를 적용하 면 복합초경계 (TiCN-WC-Co)에서도 입자성장이 억제되고 치밀한 소결체를 제조할 수 있을 것이다. 본 실험에서는 평균입도가 각각 0.1, 1.33, 2$\mu\textrm{m}$인 TiCN, WC, Co 분말을 사용하여 $((I00_{-x)}TiCN+_xWC)-30Co$ (wt%) 조성에서 TiCN/WC 비를 변화시키면서 업자 모양과 입자성장 거동을 관찰하였다. 청량된 분말은 WC 초경 볼로 밀렁하고, 건조한 후, 100 mesh 체로 조립화 하였다. 이 분말을 100 MPa의 압력으로 냉간정수압성형 하고 $10^{-2}$ torr의 진공분위기의 graphite f furnace에서 carbon black으로 packing 하여 액상형성 온도 이상에서 소결하였다. 소결된 시편은 경면 연마하여 주사전자현미경으로 미세 조직을 관찰하였다. TiCN-30Co 조성 시편은 corner-round 모양의 입자 모양으로 소결 시간 증가에 따라 빠른 입자 성장을 나타내었다 .(7STiCN+2SWC)-30Co 조성 시변의 경우 일반적으로 보고된 바와 같이 core/shell 구조를 나타내었으며, core는 TiC-rich 상이었고, shell은 (Ti,W)(C,N) 복합 탄화물 상이었다. WC 함량이 중가함에 따라 입자의 corner-round 영역이 증가하였으며 (SOTiCN-SOWC)-30Co 조성 근처에서는 거의 둥근 형태의 입자 모양을 나타내었다. 또한 TiCN - 30Co 조성 시편에 비하여 WC가 첨가된 시펀들은 작은 평균입자크기를 나타내었다. 본 연구의 결과는 shell 영역 조성 변화는 계면에너지 이방성과 기지상 내의 펑형 입자 모양을 변화시키고 나아가 입자 성장 속도 에도 영향을 미친다는 것을 보여준다.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.5
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• pp.233-238
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• 2010

The phase transformations and the shape memory effect in In-rich Pb alloys and In rich-Sn alloys have been studied by means of X-ray diffractometry supplemented by metallographic observations. The alloys containing 12~15 at.%Pb transform from the ${\alpha}_2$ (fct) phase to the ${\alpha}_1$ (fct) phase by way of an intermediate phase (m phase) on cooling. The results of X-ray diffraction show that the metastable intermediate phase is observed both on cooling and heating, and has a face-centered orthorhombic (fco) structure. It is concluded that the ${\alpha}_1{\rightleftarrows}{\alpha}_2$ transformation is expressed by the ${\alpha}_1{\rightleftarrows}m{\rightleftarrows}{\alpha}_2$ transformation both on usual cooling and heating with the rate more than $8{\times}10^{-3}$ K/s. The $m{\rightleftarrows}{\alpha}_2$ transformation takes place with a mechanism involving macroscopic shear and are of diffusionless (martensitic) type. The temperature hysteresis in the two transformations is 10~13 K between the heating and cooling transformations. The alloys containing 0~11 at.%Sn are -phase solid solutions with a face centered tetragonal structure (c/a > 1) at room temperature, the axial ratio increasing continuously with tin content. The In-(11~15) at.%Sn alloys are mixtures of ${\alpha}$ and ${\beta}$ phases, the ${\beta}$ phase having a f. c. tetragonal structure (c/a < 1). The alloys containing more than 15 at.%Sn are ${\beta}$-phase solid solutions. The In-(12.9~15.0) at.%Sn alloys show a shape memory effect only when quenched to the temperature of liquid nitrogen, although their effect becomes weak and finally disappears after keeping at room temperature for a long time. The ${\beta}{\rightarrow}{\alpha}^{\prime}$ phase transformation is of the diffusionless (martensitic) type, and takes place between 330 K at 12.9 at.%Sn and 150 K at 14.5 at.%Sn. The hysteresis of transformation temperatures on heating and cooling is considerably large (29~40 K), depending on the composition. Both In-Pb and In-Sn alloys showed distinct the shape memory effects.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.5
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• pp.75-84
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• 2016

This paper presents an investigation of the mechanical properties on non-sintered cement pastes immersed in sea waters at three different temperatures. The non-sintered cement pastes were synthesized using blended binder(Class F fly ash; FA and ground granulated blast furnace slag; GGBFS) and alkali activator(sodium hydroxide and sodium silicate). Binders were prepared by mixing the FA and GGBFS in different blend weight ratios of 6:4, 7:3 and 8:2. The alkali activators were used 5wt% of blended binder, respectively. Calcium carbonate was used as an chemical additive. The compressive strength, bulk density and absorption of alkali-activated FA-GGBFS blends pastes were measured at 3 and 28 days after immersed in sea waters at three different temperatures($5^{\circ}C$, $15^{\circ}C$ and $25^{\circ}C$). The XRD and SEM tests of the pastes were conducted at 28 days. Water-soluble chloride(free chloride) and acid-soluble chloride(total chloride) contents in the pastes were also measured after 28 days immersion in sea water. The experimental results showed that increasing the content of FA in alkali-activated FA-GGBFS blends pastes immersed in sea water increases the absorption, water-soluble chloride content and acid-soluble chloride content, and reduces the compressive strength and bulk density. And it was found that there was a variation of strength change for the alkali-activated FA-GGBFS blends pastes immersed in sea waters at three different temperatures that depends on the blending ratio of FA and GGBFS.