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A Study on the Hardening Characteristics of Ground Injection Grout under Various Curing Conditions (다양한 양생조건에서 지반주입 그라우트의 경화특성에 대한 연구)

  • Heo, Hyungseok;Park, Innjoon
    • Journal of the Korean GEO-environmental Society
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    • v.21 no.11
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    • pp.11-20
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    • 2020
  • For water barrier and reinforcing grout in soft ground, the verification of durability was conducted over the initial and long-term ages under various curing conditions. The grout was made of water glass system, fast-hardening mineral (FHM) system, and acrylic polymer system. There were three types of curing conditions that were tab water curing, artificial seawater curing, and atmospheric curing. And the various tests were performed for each sample by age, uniaxial compressive strength, length change, and weight change. As artificial seawater, MgCl2 and MgSO4 aqueous solutions were prepared and used, respectively. As the test results, the fast-hardening mineral system and acrylic polymer system were cured stably without significant change in durability in tap water and artificial sea water, whereas water glass system showed a very rapid drop in durability under artificial sea water conditions compared to tap water. In atmospheric curing conditions, durability is lowered compared to water curing in all cases, and in particular, the weight loss in the FHM system and water glass system is about 62% and 60%, respectively, resulting in a significant decrease in durability.

Comparison of Damping for Steel Tall Buildings by Half Power Bandwidth and Random Decrement Method (철골조 고층건물의 하프파워법과 RD법에 의한 감쇠율 비교)

  • Yoon, Sung-Won;Ju, Young Kyu;Shin, Sang Jun
    • Journal of Korean Society of Steel Construction
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    • v.19 no.1
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    • pp.107-115
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    • 2007
  • In this paper, the damping ratios of two methods, namely the half-power bandwidth method and random decrement method from the vibration measurement were examined. Ambient vibration tests were conducted on two steel-framed and one composite tall building ranging from 27 to 36 stories. The performance of the half-power bandwidth method was investigated using four sample sizes, such as 1024, 2048, 4096 and 8192. Damping by the half-power bandwidth method is slightly more overestimated than the random decrement method due to insufficient record length. Damping evaluation by the half-power bandwidth method was found to be enhanced when using the narrower bandwidth with long recorded data.

Depth Image based Chinese Learning Machine System Using Adjusted Chain Code (깊이 영상 기반 적응적 체인 코드를 이용한 한자 학습 시스템)

  • Kim, Kisang;Choi, Hyung-Il
    • The Journal of the Korea Contents Association
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    • v.14 no.12
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    • pp.545-554
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    • 2014
  • In this paper, we propose online Chinese character learning machine with a depth camera, where a system presents a Chinese character on a screen and a user is supposed to draw the presented Chinese character by his or her hand gesture. We develop the hand tracking method and suggest the adjusted chain code to represent constituent strokes of a Chinese character. For hand tracking, a fingertip is detected and verified. The adjusted chain code is designed to contain the information on order and relative length of each constituent stroke as well as the information on the directional variation of sample points. Such information is very efficient for a real-time match process and checking incorrectly drawn parts of a stroke.

Cu/Si/Cu Ohmic contacts to n-type 4H-SiC (n형 4H-SiC의 Cu/Si/Cu 오옴성 접합)

  • 정경화;조남인;김민철
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2002.11a
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    • pp.73-77
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    • 2002
  • Characteristics of Cu/Si/Cu ohmic contacts to n-type 4H-SiC were investigated systematically. The ohmic contacts were formed by rf sputtering of multi layer Cu/Si/Cu sputtered sequentially. The annealings were peformed With 2-Step using RTP in vacuum ambient. The specific contact resistivity($\rho$c), sheet resistance(Rs), contact resistance(Rc), transfer length(L$_{T}$) were calculated from resistance(R$_{T}$) versus contact spacing(d) measurements obtained from TLM(transmission line method) structure. Best results were obtained for a sample annealed at vacuum as $\rho$c = 1.0x10$^{-6}$ $\Omega$$\textrm{cm}^2$, Rc = 2$\Omega$ and L$_{T}$ = 1${\mu}{\textrm}{m}$. The physical properties of contacts were examined using XRO and AES. The results showed that copper silicide was formed on SiC and Cu was migrated into SiC.o SiC.

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A Study on The Status of Health Examination and Health Management of Industrial Companies in the Taegu and Kyungbook Areas (일부 경북지역 산업장의 제특성에 따른 건강진단과 보건관리 실태)

  • Kim, Sang-Soon;Kim, Jung-Nam;Park, Jung;Kim, Ok-Ran;Cha, Kyung-Mi;Kwak, Ou-Ke;Park, Kyung-Min;Choi, Yoon-Hee;Bak, Kyung-Shin
    • Research in Community and Public Health Nursing
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    • v.4 no.1
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    • pp.67-76
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    • 1993
  • The purpose of this study was to find the status of health examination and health management of industrial companies located in Taegu and Kyung book areas. It will provide basic information for the provision of effective health management of industrial workers. 49 companies were selected as a study sample group, and data was collected by using a structured Questionnaire which was developed by the members of the Community Health Nursing Academy of Korean Nursing. The health managers of the companies filled out the Questionnaire. The data was gathered from Dec 20, 1992 to Jan 20. The results of the study was as follows : 1. The Study sample showed 85.7% manufacturing companies having 300 or more workers. 2. All the companies had health managers, and companies which had 1,000 or more workers had industrial physicians and nurses. Only 12.2% of the industrial physicians were full time employees, and almost all industrial nurses were full time employees. Except for industrial physicians and nurses, the proportion of hygienists (6.1%), nurses aids (4.1%), and environmental engineers (22.4%) with full time employment statuss was very low. The mean age of industrial physicians was 49.2 while that of industrial nurses was 27.2. The length of work experiences currently ranges for 1 to 3 years for all health workers: physicians, nurses, hygienists, and environmental engineers. 3. Health examination and follow up care 94.31% took general health examinations. Of those, the proportion of the workers, who were determined as C grade(in need of close examination) was 43.86%. The proportion of the workers who were determined as D grade was 22.19%. 13.28% of the workers evaluated at the D grade were taken as a gauge for temporary leave from work. While 8.7% and .09% of them were taken as gauge for a change in job, and or shortening work hours respectively. The proportion of workers who must have taken special examination was 65.04% and of those the proportion of the workers who actually took, the examination was 98.55%. 75% of the workers who were recommended for follow up care were given follow up care. The special examinations were done the most frequently to detect the effects of physical agents (59.2%). Direct notice to individual workers was used the most frequently as a method of notification after a special examination (61.2%). The length of time taken to receive the result of a special examination was less than 1 month (38.9%) and 36.7% had taken up to two months (36.7%.). Most results of special examination were obtained within 2 months. The referral rate of consulting special examination by health managers was estimated at 95.9%. 4. 89.8% of the companies had. their own company dispensaries and 75.5% of those. had separate dispensaries. 32.7% of the companies designated local clinics for health management of workers. Industrial nurses performed health examination the most frequently(1.4 points). Health appraisal for work places were. done the least(0.83 points).

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Study on Sound Production and Phonotaxis of Some Fishes and Crabs (몇가지 어류 및 갑각류의 발음과 주음성에 관한 연구)

  • 김상한
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.14 no.1
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    • pp.15-36
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    • 1978
  • Underwater sounds of some fishes and crabs were analyzed in the laboratory. The behavioral responses to the playback sounds of their feeding and croaking sound were investigated. The samples used in the experiment were as follows: Nibea albiflora, seriola quinqueradiata, Navodon modestus, Fugu xanthopterus, chrysophrys major, Scylla serrata, Telmessus acutidens, Charybdis japonica, and Portunus trituberculatus. The feeding and croaking sounds of the samples were recorded by a tape recorder through a hydrophone in an anechoic aquarium. The sound intensity level was measured by means of a sound level meter at an anechoic chamber. The frequency, intensity and wave form of various sounds were analyzed with an analyzing system consisting of a 1/3 octave filter set, a high speed level recorder, an amplifier, an octave band analyzer and an oscilloscope. The most successful recording was edited into a sequence of sound track which repeats sound emitting for 5 to 7 seconds after pausing for 5 to 7 seconds. The sequence was then reproduced into an anechoic aquarium through the under water speaker. The experimental anechoic aquarium used for the sample fishes was divided into the four sections with any three screens selected from 40$\times$40mm, 60$\times$60mm, 80$\times$80mm and 100$\times$100mm mushes according to the species of the fishes, besides that for crabs were not sectioned. The results of the investigation are as follows: 1. Of the feeding sound of fish, the frequency of wave from of the sound produced by Nibea albiflora and seriola quinqucradiata was 125~250Hz, that by Navodon modestus 63~125Hz, and that by Fugu xanthopterus 400~500Hz. The pressure level of the feeding sound produced by Nibea albiflora and Seriola quinqueradiata was 56~62db, that by Navodon modestus 57~59db, and that by Fugu xanthopterus 60~64db. 2. Of the croaking sound of Nibea albiflora, the frequency of the sound was 125~250Hz almost equivalent to that of feeding sound, and the pressure level was 62~63db, slightly higher than that of feeding sound. 3. Of the croaking sounds of crabs, the frequency of the sound produced by scylla serrata was 125~250Hz, that by Charybdis japonica and Telmessus acutidens 500~1,000Hz, and that by Portunus trituberculatus 250~500Hz. The pressure level of the croaking sound by Scylla serrata was 68~70db, and that by Charybdis japonica, Telmessus acutidens and Portuens trituberculatus 50~62db. 4. Phonotactic responses of Nibea albiflora and Seriola quinqueradiata to the feeding sounds produced by their own species, the same body length were conspicuous with the phonotactic index of 56~87%, but that of Navodon modestus, Chrysophrys major and Fugu xanthopterus were hardly recognized. 5. Phonotactic responses of the sample fishes to the sinusoidal sound with the frequency range of 50 to 9,000 Hz were observed not conspicuous. 6. Phonotactic responses of Portunus trituberculatus to the croaking sounds produced by their own species was varied in the range of 40~100%, according to the carapace length and the sex.

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CRANIOFACIAL STRUCTURE AND ARCH DIMENSION OF ADULT CLASS III MALOCCLUSION (성인 III급 부정교합자의 악안면골격구조 및 치열궁형태에 관한 연구)

  • Lee, Dong-Geun;Suhr, Cheong
    • The korean journal of orthodontics
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    • v.27 no.3 s.62
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    • pp.359-372
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    • 1997
  • This study was conducted to discern differences of craniofacial, dentoalveolar structure and model measurements between sex and between class n openbite group and non-openbite group. The sample consisted of 49 adult patients with class Il malocclusion. 24 linear measurements, 22 angular measurements and 12 ratios were selected in lateral cephalometry. Also, arch width, length, anterior crowding, average molar relation were measured or calculated in diagnostic model. The data were evaluated by t-test and multiple discriminant analysis. The results were as follows, 1. Most linear measurements, with the exception of MnBL and AUDH, were significantly larger in male(p<0.05). but, intermaxillary relations and spatial position of maxilla and mandible relative to cranial base were not different for both sex. 2. With the exception of upper and lower anterior crowding, lower arch width, upper arch length, AMR, male exhibited significantly larger measurements in model analysis (p<0.05). 3. Size differences of maxilla and mandible between openbite and non-openbite group were not significant(p>0.05). but openbite group showed significantly increased genial angle(p<0.05), FH-CoGo(p<0.01), FH-NA(p<0.01) and FH-NB, FH-NPog (p<0.05). 4. ALFH and PUDH were larger(p<0.05) in openbite group. this result served as compensation for the spatial position of mandible relative to cranial base. AUPUDH (p<0.001) and ALPLDH(p<0.05) were lower in openbite group. upper anterior crowding was the only measurement which showed difference between openbite and non-openbite group(p<0.05). 5. For the purpose of classifying adult class n openbite and non-openbite group, multiple discriminant analysis was done genial angle, ALPLDH, AUPUDH, FH-NA were included in multiple discriminant equation. 39 cases($92.86\%$) were correctly classified when applied to the sample used in this study.

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On the wing venation and scales of Dendrolimus spectabilis Butler (I) (솔나방의 시맥(翅脈)과 인편(鱗片)에 관(關)한 연구(硏究) (I))

  • Yun, Jeong Koo
    • Journal of Korean Society of Forest Science
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    • v.2 no.1
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    • pp.59-65
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    • 1962
  • The objects of this experiment are to find out the local variation of the Dendrolimus Spectabilis Butler, of which sample was first collecteted 15 bodies of male and 35 bodies of female adult at Suwon area. the wing veins and the scale shape have been observed through the microscope (100) and the scale size (from the bottom of the scale to the top of the lobe) has also been measured by the micrometer. The results of this experiment are as follows: 1. There is nodifference between the venation of the male body and that of the female body. Also we can not find any differences between the right and the left wing, and between each body. The fore wings consit of 13 longitudinal veins and the only one "V" shape cross vein which is between the 5th and 6th vein. The hind wings consist of 9 longitudinal veins and the only one "V" shape cross vein which is mentioned above. 2. The scale types are divided into 4 Groups in its shape. (A) The scales of I Group are short and the lower parts of them almost look like a circle, having a small projection at their bottom. The upper parts of them have 2 or 10 lobes. We can find the lobes with fine hairs or the lobes without them at the top of the scales. (B) The scales of II Group are longer than that of I Group. The shape of the lower parts of the scales is similar to that of I Group. The upper parts of the scales have 2 or 10 lobes. (C) The scales of III Group are long and almost alike in a long wedgeshape. The upper parts of the scales have 2 Or IO lobes and we can find long fine hairs at the top of each lobe. (D) The scales of IV Group are long and the shape of the lower parts of the scales is similar to that of III Group. The lobes are short and not sharp. We can find 2 or 9 lobes. 3. The scales of I Group and II Group are distributed on the whole surface except on the outer margin. The most scales of III Group are distributed on the wing base. The scales of IV Group are distributed on the outer margin only. The scales with 4 or 5 lobes are most widely distributed not considering their Group or distributing parts. 4. In I Group the variation of the scale length become gradually greater as the number of the lobes are increasing. In II, III, IV Group, however, the variation of the scale length is in direct opposition to the above mentioned. The variation of the scale width becomes pretty small in any Groups and the scale width become wider as the number of the lobes are increasing. 5. The source of the wing colouration is pigmnetal colour, and the wing colouration is expressed by the amount of brown and white scales.

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A study on analyzing effectiveness of childbirth education (임부교실 운영효과 분석을 위한 일 연구)

  • Kim, Hea Sook;Choi, Yun Soon;Chang, Soon Bok;Jung, Jae Won
    • The Korean Nurse
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    • v.34 no.3
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    • pp.85-98
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    • 1995
  • The purpose of this study is to provide basic data regarding effective learning opportunities in childbirth education classes. Also analysis of the data indicates the optimum conditions for the welfare and improvements in the promotion of health in childbearing mothers. The results of this study are as follows; 1) The average age of the subjects in this study was 30.6 years and the total number of subjects was 58 pregnant women. The average number of children was one and 84.5% of the subjects were unemployed even though 63.8% of them held over bachelor's degrees. It was found that 22.4% of the subjects were living in an extended family. Also 61.5% of them were living with parents-in-law. The number of pregnancies were calssified as one, two, or three to nine times with the percentages of 58.7%, 22.4% and 18.9%, respectively. Further, 72.4% of the subjects had no abortion experience and 15.5% had one aborion experience. While 89.7% of the subjects planned to feed their babies with breastmilk, mixed feeding were used by only 22.4% of the sample. These data were collected at about 6 months after delivery. Thus one can see that a low rate of breastfeeding was common. 2) The length of one period of childbirth education is four weeks. It was found that 36.2% of the subjects participated in childbirth education only once, where as 13.8% participated four times and 19% of the subjects participated in this class more than four times. pregnant at least once. Further, 75.9% of the participants were participated in this education through their own will. Their motivation for participation developed through information, advertisement and posters which contained information on childbirth education. Those with unplanned pregnancies 92.9% participated after a suggestion by the nurses. The number of participants in terms of percentage according to the childbirth education contents can be classified as following. The most active participation was shown in preparation of delivery(77.6%), postpartrm management(56.9%) fetal development(37.6%) and physiology of pregnancy(17.2%). It was found that 75.9% of the subjects were willing to participate again if they were given a chance. The reason can be summarized as following: The content of the education is very helpful(47.7%). Scientific knowledge can be obtained through this program(20.5%). Participation helps in achieving psychological stability(9.1%). Participation enables one to establish a friendly relationship with other participants(6.8%) of the sample. 24.1% of the participants did not want to participate again. The reasons can be as following: They do not want another baby(42.9%). The first paricipation in childbirth education gave enough knowledge about childbirth(21.4%). Another reason for not want to participate again was because they had a cesarean birth(14.3%). Only 7.1% of them responded with a negative view. A response that they do not need childbirth education after their operation can be traced back to the general belief that childbirth education is the place where one prepares for natural birth through the Lamaze breathing technique. Of the subjects, 91.4% suggested that this program could be recommended to other childbearing mothers, because this program gave educational content along with psychological stability for childbearing women. Of the subjects 41.4% did not see any efforts towards the welfare of the baby, where as 88.2% did. Among the subjects 58.6% made some effort to eliminate the discomfort of labor by breathing and imagination and breathing and walking. Further 41.7% of the 24 subjects did not do anything toward the welfare of the baby, because they did have a cesarean section so that they didn't have a chance even though they had been educated about childbirth. Also 33.3% of the subjects did not do anything toward the welfare of the baby, because they lacked a willingness. After leaving the hospital, only 75.9% of the subjects did some exercises. The subjects who tried participate this program with their husband accounted for 20.7% of the sample. Interviewing with the subjects solved some of the uneasiness and. fear of delivery, increased self-confidence in parenting and active coping in the delivery process.

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Studies on Wood Quality of Pinus koraiensis Sieb. et Zucc. (III) - On Annual Ring Width and Summer Wood Percentage - (잣나무의 재질(材質)에 관(關)한 연구(硏究) (제(第) III 보(報)) - 연륜폭(年輪幅)과 추재율(秋材率) -)

  • Lee, Won Yong
    • Journal of Korean Society of Forest Science
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    • v.24 no.1
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    • pp.25-44
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    • 1974
  • In the present paper I described the results of the observations made on the visual characteristics such as the annual ring width and summerwood percentage of Pinus koraiensis Sieb. et Zucc. grown at out university forest. The results of the study are as follows: Characteristics of annual ring width and summerwood percentage 1. The range of dispersion of annual ring width and summerwood percentage are respectively 0.5-6.5mm and 5-50% on the normal wood and its arithmetic mean values are each 3.0mm and 24% on all sample trees. 2. The values of annual ring width of heart wood are larger than that of sapwood but on the contrary the values of summerwood percentage of heartwood are smaller than that of sapwood. On the other hand variations of these values are distingushed on the heartwood. 3. The values of annual ring width due to the parts of stem with crown. with clear length and at bottom showed that the largest values are given at the parts of stem with crown. But on the contrary the summerwood percentage values are largest at the parts of stem at bottom on all sample trees. 4. The values of annual ring width and summerwood percentage depending on the stand sides are not obvious. Horizontal and vertical variations of annual ring width and summerwood percentage 5. It was recognized that horizontal (radial direction) variations of annual ring width and summerwood percentage indicated two different patterns (the region of large fluctuation and that of small fluctuation) in a tree stem. These boundaries are seemed to appear at the parts of 12-15 annual rings from pith. 6. According to the increase of height in tree the values of annual ring width increase but the values of summerwood percentage gradually decrease. 7. But vertical variations of annual ring width and summerwood percentage on the sapwood are divided into two different parts (region of increased or decreased upwards and that of remained constant in successive height) in a tree stem and these limits are seemed to appear at the 7m of height in trees. Relations between annual ring width and summerwood percentage 8. The modes of summerwood percentage related with annual ring width are seemed to appear almost in the definite range (10-25%). 9. The relations between annual ring width and summerwood percentage show a highly negatine correlation on all sample trees.

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