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Cyclic Seismic Testing of Cruciform Concrete-Filled U-Shape Steel Beam-to-H Column Composite Connections (콘크리트채움 U형합성보-H형강기둥 십자형 합성접합부의 내진성능)

  • Park, Chang-Hee;Lee, Cheol-Ho;Park, Hong-Gun;Hwang, Hyeon-Jong;Lee, Chang-Nam;Kim, Hyoung-Seop;Kim, Sung-Bae
    • Journal of Korean Society of Steel Construction
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    • v.23 no.4
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    • pp.503-514
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    • 2011
  • In this research, the seismic connection details for two concrete-filled U-shape steel beam-to-H columns were proposed and cyclically tested under a full-scale cruciform configuration. The key connecting components included the U-shape steel section (450 and 550 mm deep for specimens A and B, respectively), a concrete floor slab with a ribbed deck (165 mm deep for both specimens), welded couplers and rebars for negative moment transfer, and shear studs for full composite action and strengthening plates. Considering the unique constructional nature of the proposed connection, the critical limit states, such as the weld fracture, anchorage failure of the welded coupler, local buckling, concrete crushing, and rebar buckling, were carefully addressed in the specimen design. The test results showed that the connection details and design methods proposed in this study can well control the critical limit states mentioned above. Especially, the proposed connection according to the strengthening strategy successfully pushed the plastic hinge to the tip of the strengthened zone, as intended in the design, and was very effective in protecting the more vulnerable beam-to-column welded joint. The maximum story drift capacities of 6.0 and 6.8% radians were achieved in specimens A and B, respectively, thus far exceeding the minimumlimit of 4% radians required of special moment frames. Low-cycle fatigue fracture across the beam bottom flange at a 6% drift level was the final failure mode of specimen A. Specimen B failed through the fracture of the top splice plate of the bolted splice at a very high drift ratio of 8.0% radian.

A Study on the Dental Hygienists' Reactions to Noise When Occurred in Dental Clinic (치과병원에서 발생하는 소음에 대한 치과위생사의 반응)

  • Choi, Mi-Suk;Ji, Dong-Ha
    • Journal of dental hygiene science
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    • v.9 no.4
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    • pp.453-459
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    • 2009
  • The purposes of this research were to evaluate the relationships of between characteristics of noise and annoyance of dental hygienist by noise in dental clinic. To investigate the dental clinic workers' reactions to noise when occurred in dental clinic, the noise level test in dental clinic and questionnaire were taken. As a result of noise evaluation, It shows that the range of noise level was 67.7~78.3dB(A) and frequency was very high (more than 4KHz). It's seem to be begins occurrence of stamina-loss, contraction of peripheral blood vessel, decrease of adrenocortical hormones. Most of respondents were affected by noise: 67% of respondents were nervous about noise and the rest of respondents were bearable. Analysis by NR-curve showed that it was exceed the noise permit level in working space. As a result of correlation - test, the more exposed dental hygienist to noise, the more felt the unpleasantness and fatigue. It's hard to sufficient explanation to patients about the dental treatment. So it's thoughts that insufficient explanation will negative impact on the patients' satisfaction and increase competitiveness in dental clinics. To remedy a unpleasantness and fatigue of noise in dental hygienist, it's considered that making an offer the ear protection and choosing the low noise-vib. equipment and using the masking effect. Therefore, It can be provide a pleasant working environment with dental hygienist and It will have a great advantage to dental clinics to improve their competitiveness.

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Consumption and Preference for Bokbunja (Rubus coreanus Miquel) Products (복분자 제품에 대한 기호도 및 이용실태 조사)

  • Lee, Jeong-Ae;Park, Geum-Soon
    • Korean journal of food and cookery science
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    • v.27 no.3
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    • pp.11-20
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    • 2011
  • The purpose of this study was to investigate the use and perception of adults concerning bokbunja (Rubus coreanus Miquel) products. Self-administered questionnaires were collected from 502 residents in the Daegu and Gyeongbuk area. According to the survey more females in their 20s responded than males (45.2 and 54.8%, respectively). In total, 82.6% of respondents had an income of under 4,000,000 won per month and most were living in the city. The results regarding knowledge about bokbunja products showed that the bokbunja wine score was highest (3.66), and intake frequency showed that over half of the respondents had never eaten bokbunja products. The preference for bokbunja wine by males was higher than that for females, whereas the others products showed higher scores for females than for males. When asked about how they knew about bokbunja products, 37.0% of males and 46.9% of females responded a family member or neighbor. When purchasing bokbunja products, males and females answered that they considered taste, country of origin, and manufacturer, and price. Approximately 48% of the respondents answered that they purchased bokbunja products in the grocery and department store. As a result, popularization of bokbunja products was based on product development and sales promotion, and the product development factor significantly influenced preference for bokbunja products.

A Study on the Optimum Design of Multiple Screw Type Dryer for Treatment of Sewage Sludge (하수슬러지 처리를 위한 다축 스크류 난류 접촉식 건조기의 최적 설계 연구)

  • Na, En-Soo;Shin, Sung-Soo;Shin, Mi-Soo;Jang, Dong-Soon
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.4
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    • pp.223-231
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    • 2012
  • The purpose of this study is to investigate basically the mechanism of heat transfer by the resolution of complex fluid flow inside a sophisticated designed screw dryer for the treatment of sewage sludge by using numerical analysis and experimental study. By doing this, the result was quite helpful to obtain the design criteria for enhancing drying efficiency, thereby achieving the optimal design of a multiple screw type dryer for treating inorganic and organic sludge wastes. One notable design feature of the dryer was to bypass a certain of fraction of the hot combustion gases into the bottom of the screw cylinder, by the fluid flow induction, across the delicately designed holes on the screw surface to agitate internally the sticky sludges. This offers many benefits not only in the enhancement of thermal efficiency even for the high viscosity material but also greater flexibility in the application of system design and operation. However, one careful precaution was made in operation in that when distributing the hot flue gas over the lump of sludge for internal agitation not to make any pore blocking and to avoid too much pressure drop caused by inertial resistance across the lump of sludge. The optimal retention time for rotating the screw at 1 rpm in order to treat 200 kg/hr of sewage sludge was determined empirically about 100 minutes. The corresponding optimal heat source was found to be 150,000 kcal/hr. A series of numerical calculation is performed to resolve flow characteristics in order to assist in the system design as function of important system and operational variables. The numerical calculation is successfully evaluated against experimental temperature profile and flow field characteristics. In general, the calculation results are physically reasonable and consistent in parametric study. In further studies, more quantitative data analyses such as pressure drop across the type and loading of drying sludge will be made for the system evaluation in experiment and calculation.

Study on Effect of Varience of Physiological Responses in Color Foot Reflexology Using Color Light (컬러광을 활용한 발반사요법이 인체 생리적 반응 변화에 미치는 영향에 관한 연구)

  • Jin, Hye-Ryeon;Yu, Mi;Park, Kyung-Jun;Kim, Nam-Gyun;Chung, Sung-Whan;Kim, Dong-Wook
    • Science of Emotion and Sensibility
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    • v.13 no.1
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    • pp.187-196
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    • 2010
  • Recently, people have been suffering from stress-related fatigue and psychological disorders. Most people depend on medicine for pain relief; many treat pain also through alternative medicine or replacement therapy. However, drug therapy has many side effects, including increased stress after the therapy. In comparison, alternative therapies such as massage and foot reflexology are less damaging to the body, and such therapies can be provided without physical or psychological discomfort. In this regard, the author had previously co-developed color foot reflexology, which combines the merits of color therapy and foot reflexology; color foot reflexology has been shown to have beneficial effects without undue pain. This study investigates the effects of color foot reflexology on the physiological response of the body by comparing the body’s response to the signal with that to the placebo. Healthy adult subjects were selected for the experiment, which was conducted under optimal experimental conditions and design. The results indicated that when stimulated, parasympathetic nerves increased in HRV and that blood pressure, pulse, body heat, peripheral blood flow were dramatically activated. However, the results for the placebo indicated minimal changes or irregular outcomes. The results provide strong evidence for the beneficial effects of the color foot reflexology instrument on the autonomic nervous system and on the physiological response of the body. Future research is warranted to verify the results of the current study by examining patients suffering from diseases and disorders arising from irregular physiological functions in the context of the foot.

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Spectral Analysis of Hidden EEG Arousal Activity in Periodic Leg Movements in Sleep without Microarousal (미세각성이 없는 수면중 주기성 사지운동증 뇌파의 스펙트럼 분석)

  • Cyn, Jae-Gong;Seo, Wan-Seok;Oh, Jung-Su;Jeong, Do-Un
    • Sleep Medicine and Psychophysiology
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    • v.10 no.2
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    • pp.100-107
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    • 2003
  • Objectives: Periodic leg movements in sleep (PLMS) might be subdivided based upon whether or not they are associated with visible EEG microarousals (MA). MA is considered to be responsible for nonrestorative sleep and daytime fatigue. The American Sleep Disorders Association's (ASDA) scoring rules for MA based on visual analysis of the EEG changes suggest that MA should last more than 3 seconds. However, it has been suggested that visual analysis may not detect some changes in EEG activity. This study is aimed at measuring changes in EEG spectra during PLMS without MA in order to better understand the arousing response of PLMS. Methods: Ten drug-free patients (three men and seven women) diagnosed with PLMS by polysomnography were studied. Spectral analysis of the EEG was performed in each patient on 30 episodes of PLMS without MA, chosen randomly across the night in stage 2 non-REM sleep. We applied stricter criteria for MA compared to ASDA, by defining it as a return to alpha and theta frequency lasting at least 1 second. Results: The mean PLMS index was $16.7{\pm}10.0$. The mean PLMS duration was $1.3{\pm}0.7$ seconds. Comparison of 4-second EEG activity both before and after the onset of PLMS without MA using independent t-test showed that the movements were associated with significant increase of relative activity in the delta band (p=0.000) and significant decrease of activity in the alpha (p=0.01) and sigma (p=0.000) bands. No significant decrease in the theta (p=0.05), beta (p=0.129), or gamma (p=0.062) bands was found. Conclusion: PLMS without MA was found to be associated with EEG change characterized by increase in the delta frequency band. This finding seems to be compatible with the hypothesis of an integrative hierarchy of arousal responses of Sforza's. Considering that the subjects had lower PLMS index and shorter PLMS duration than those of the previous study, it is suggested that an even less severe form of PLMS without MA could induce neurophysiologic change, which may potentially be of clinical significance.

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Effect of Noise in Human Body (소음이 인체에 미치는 영향)

  • 이영노
    • Proceedings of the KOR-BRONCHOESO Conference
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    • pp.7-8
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    • 1972
  • The effects of noise exposure are of two types: Nonauditory effects and auditory effects. Nonauditory effects of noise exposure are interference with communication by speech, sleeping and emotional behavior. The noise will cause the high blood pressure and rapid pulse, also that decrease the salivation and gastric juice. in experimentaly showed that the Corticoid hormon: Gonatotropic hormone were decrease and Thyrotropic hormoone is increase. Auditory effect of noise exposure. when the normal ear is exposed to noise at noise at hamful intensities (above 90㏈) for sufficiently long periods of time, a temoral depression of hearing results, disappearing after minutes or hours of rest. When the exposure longer or intesity greater is reached the Permanent threshold shift called noise-induced hearing loss. Hearing loss resulting from noise exposure presents legal as well as medical problems. The otologist who examines and evaluates the industrial hearing loss cases must be properly informed, not only concerning the otologic but also about the physical and legal aspects of the problems. The measurement of hearing ability is the most important part of a hearing conservation, both preplacement and periodic follow-up tests of hearing. The ideal hearing conservation program would be able to reduce or eliminate the hazardous noise at its source or by acoustic isolation of noisy working area and two ear protections (plugs and muff type) were developed for personal protection.

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A Study on Anxiety-Depression in College Freshmen (신불안.우울척도에 의한 대학 신입생의 정신건강 평가)

  • Park, Hyeong-Bae;Kim, Jin-Sung;Kim, Chang-Su;Park, Byung-Tak;Lee, Jong-Bum;Lee, Jung-Hoon;Cheung, Seung-Douk
    • Yeungnam University Journal of Medicine
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    • v.4 no.1
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    • pp.105-121
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    • 1987
  • The authors studied anxiety-depression using New Anxiety-Depression Scale(NADS), in the subjects of 3,499male and 1,335 female college freshmen of Yeungnam University. The authors collected the reports of NADS during the periods from January to February, 1986, and applied ANOVA and t-test on anxiety-depression scores in order to compare them between various psychosocial factors, and sexs. The results are as follows : There was significant difference in the mean awerages of total scores between male and female students: male students scored $31.49{\pm}6.57$ female students scored $33.37{\pm}6.84$ (P<0.001) The anxiety-depression scores relating to the items of sleep disturbance, apprehension, decreased libido and fatigue were relatively higher in both groups. Ninety-nine male students(2.8%) showed seriously high degree anxiety-depression scores of 50 or higher, while forty female students(3.0%) showed the same scores. There was a strong tendency toward higher anxiety-depression scores in the students who were dissatisfied with their home atmosphere, colleges, departments and familiarity of parents, and those who had pessimistic views of self image in the past, present, or fartare in both groups (P<0.001) The students whose maturation locations were below city level, showed higher level of anxiety-depression scores in both groups (P<0.05) NADS and SAS, SDS, and Leeds scale were correlated significantly in 0.64, 0.61, and 0.77 of correlation coefficient.

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Effect of the Early Traumatic Experience on the Mental Health of the Elderly (조기경험이 노인 정신건강에 미치는 영향)

  • Lee, Kwang-Hun;Lee, Jung-Hoon;Lee, Jong-Bum;Park, Byung-Tak;Cheung, Seung-Douk
    • Yeungnam University Journal of Medicine
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    • v.7 no.2
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    • pp.67-77
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    • 1990
  • This study was intended to analyse the relation between the psychic traumatic experience and the psychological health of the aged. The authors carried out this study by means of the combined anxiety-depression scale(CADS) and the preadolescence traumatic experience scale(PTES) with 278 aged men and women residing in Taegu from September to October 1988. The results were as follows : 1. Based on the scores avaluated by CADS, the scores of the both groups showed that comparative group was accounted for $40.15{\pm}6.19$, while the experimental group for $57.75{\pm}6.37$, which showed significantly higher score in the experimental group(p<0.001). 2. The experimental group showed significantly higher early experience score than the comparative group in the dietary difficulty, alcoholism among family members, disunion between husband and wife, trouble between mother and children, early mother loss, parent's indifference and unwanted birth(p<0.001). 3. The experimental group showed higher early experience score than the comparative group by sex, age, marital status and grown location(p<0.001). 4. When the subjects were included in the unemployed and in the middle or low classes and their parents were engaged in agriculture and commercial business and believing in buddhism or non-religion, showed higher experience score (p<0.001).

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Comparison on the Extraction Efficiency and Antioxidant Activity of Flavonoid from Citrus Peel by Different Extraction Methods (추출방법에 따른 감귤 과피 유래 Flavonoid의 추출효율 및 항산화 효과에 대한 비교)

  • Cheigh, Chan-Ick;Jung, Won-Guen;Chung, Eun-Young;Ko, Min-Jung;Cho, Sang-Woo;Lee, Jae-Hwan;Chang, Pahn-Shick;Park, Young-Seo;Paik, Hyun-Dong;Kim, Kee-Tae;Chung, Myong-Soo
    • Food Engineering Progress
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    • v.14 no.2
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    • pp.166-172
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    • 2010
  • The extraction of polyphenol and flavonoid from citrus peel was performed by the ethanol, sugar, hot water (80$^{\circ}C$), and subcritical water extraction methods. The maximum yields of total polyphenolic compounds (27.25${\pm}$1.33 mg QE/g DCP, QE and DCP indicate quercetin equivalent and dried citrus peel, respectively) and flavonoids (7.31${\pm}$0.41 mg QE/g DCP) were obtained by subcritical water extraction (SWE) with operating conditions of 190$^{\circ}C$, 1300 psi, and 10 min. The yields by SWE were over 7.2-, and 8.5-fold higher than those of total polyphenols (3.79${\pm}$0.73 mg QE/g DCP) and flavonoids (0.86${\pm}$0.27 mg QE/g DCP) obtained using the ethanol extraction, which showed the highest extraction efficiency among tested conventional methods, respectively. Antioxidant activities of extracts obtained by different methods showed no significant differences. However, the relative antioxidant yield per 1 g dried citrus peel by SWE (190$^{\circ}C$, 10 min) was over 9.5-fold higher than that by the ethanol extraction.