• 한국과학교육학회지
• /
• 제37권4호
• /
• pp.599-609
• /
• 2017

본 연구의 목적은 TIMSS 2011과 TIMSS 2015에서 우리나라 초등학교 4학년 학생들의 성취 특성 추이변화를 분석하고 우리나라 초등과학과 교육과정 및 교수학습 개선에 주는 시사점을 도출하려는 것이다. 이를 위해 초등학교 현장교사 네 명과 과학교육을 전공한 연구자 세 명이 참여하여 TIMSS 2015의 초등학교 과학과 내용영역별 평가주제와 문항에 대해 교육과정 일치도를 분석하고, 우리나라 학생들의 성취 특성을 분석하였다. 연구결과에 따르면, 생명과학, 물상과학 그리고 지구과학의 영역을 막론하고 초등학교 3-4학년군 교육과정에서 다룬 내용일수록 정답률이 높게 나타났다. 또한 2009개정 교육과정에서 초등학교 5-6학년군에서 다루는 열전달, 전기의 작용, 지구와 달의 운동 등과 관련된 문항에서는 정답률이 상대적으로 낮게 나타났다. 과학 인지영역별로는 TIMSS 2015에서 우리나라 초4 학생들은 TIMSS 2011에 비해 추론하기 영역의 점수가 많이 하락한 것으로 나타났다. 연구결과를 토대로 우리나라 초등 과학과 교육과정 구성을 위한 시사점과 교수학습 방법 개선 방안을 제안하였다.

• Korean Journal of Acupuncture
• /
• 제40권4호
• /
• pp.156-168
• /
• 2023

Objectives : This study aimed to determine the status of thermal stimulation devices approved in Korea for medical applications over the past 10 years, and based on this, to obtain insight for future thermal treatment in Korean medical institutions. Methods : We searched the item classification list entitled "Regulations on Medical Device Items and Rating by Item" from the Ministry of Food and Drug Safety Notice No. 2021-24, 2021 (Enforced March 19, 2021; www.mfds.go.kr) for individually licensed heaters using the terms "heat" and "heating". Results : We identified 17 items of thermal stimulation product group, of which 1,308 devices were licensed by February 4, 2022, and 53.2% of them (n=696) were devices with valid permits for distribution in Korea. Among the licensed devices, heating pad systems under/overlay (electric, home use) were approved the most, but combinational stimulator (for medical use, home use; Grade 2) accounted for the highest percentage among the current valid permission. Moxibustion apparatuses were licensed separately for electrical use and non-electrical use, and occupied a low percentage of the total devices. We analyzed 307 devices that were accompanied by technical documents and found that the heat sources were wires in 145 (47.2%), infrared rays in 44 (14.3%) and ultrasonic waves in 42 (13.7%) devices. Most (83.1%) devices were used for pain relief, while other applications included beauty, cancer treatment, maintenance of infant body temperature, and healing fractures. Conclusions : Thermal stimulation devices accounted for about 0.9% of all medical devices, and among them, combinational stimulators and heating pad systems under/overlay had the most valid permits. Thermal stimulation devices using heating wires and infrared rays were the most prevalent, and most were used to relieve pain. In order to develop a range of thermal stimulation devices that can be utilized in Korean medical institutions, it is imperative that they have potential applications beyond pain management, addressing various medical purposes. To achieve this, foundational research is necessary to effectively apply diverse heat sources based on medical objectives.

• 한국가스학회지
• /
• 제20권5호
• /
• pp.50-56
• /
• 2016

본 연구에서는 개방형 무급유식 스크롤 압축기를 개조하여 유기랭킨사이클(ORC)용 소형의 스크롤 팽창기를 설계 및 제작하였다. 팽창기 케이스는 직육면체 형태로 총 체적은 $0.0394m^3$이며, 성능특성 연구를 위해 작동유체로 R245fa를 사용하는 ORC 사이클을 구축하고, 다양한 팽창기 입구압력 및 회전속도 조건에서 성능시험을 수행하였다. 성능시험에서 획득한 열역학적 물성값을 스크롤 팽창기의 semi-empirical 시뮬레이션 모델에 적용해 파라미터를 계산하고, 열역학적 분석을 통해 계산한 실험값과 시뮬레이션값의 비교를 수행하였다.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
• /
• pp.384-389
• /
• 2002

This study was aimed to evaluate the weldability and optimize the welding conditions for flash butt welding of 780MPa grade steel applied to the automotive bumper reinforcement. And then the relationship between the welding conditions and the joint performance relating specifically to coil-joining steel would be established. The effect of welding conditions between flashing and upsetting process was elucidated. Microstructure observation of the joint indicated that the decarburized band was mainly changed with upsetting process. Width of HAZ was also related to the upsetting conditions rather than the flashing conditions. Generally maximum hardness at HAZ was correlated with $C_{eq}$ of steel and the empirical relationship was obtained to estimate the HAZ properties. Tensile elongation at the joint was usually decreased with increasing the initial clamping distance. Investigation of fracture surface after tensile and bending tests reveal that the origin of cracking at the joint was oxide inclusions composed of $SiO_2$, MnO, $Al_2$ $O_3$, and/or FeO. The amount of inclusions was dependent on the composition ratio of Mn/Si in steel. If this ratio was above 4, the amount of inclusions was low and then the resistance to cracking at the joint was enough to maintain the joint performance. It was obtained that the flashing process influenced the conditions for the energy input to establish uniform or non-uniform molten layer, while the upsetting conditions influenced the joint strength. Heat input variable during flashing process was also discussed with the joint properties.

• Child Health Nursing Research
• /
• 제16권4호
• /
• pp.268-276
• /
• 2010

Purpose: The purpose of this study was to provide basic data to improve coping abilities of elementary school students in emergency situations. Method: The data were collected from 1633 3-6th grade elementary school students using a self-report questionnaire. Results: 1) The mean score for the coping ability of the students was low at .38(${\pm}.36$). 2) The mean scores for the 8 categories were, [Care for common symptoms], .54(${\pm}.48$), [Call for help & check], .47(${\pm}.43$), [Care for injury by heat cold & foreign body], .39(${\pm}.45$), [Care for tissue damage], .36(${\pm}.44$), [Offering help], .36(${\pm}.42$), [Rescue & escape], .31(${\pm}.51$), [Evacuation], .28(${\pm}.49$), and [Appropriate response for the situation], .27(${\pm}.43$). The mean scores for 2 areas were, 'Acting tips', .35(${\pm}.36$) and 'First aid', .42(${\pm}.40$). There were significant differences in coping ability according to students' gender (t=4.964, p<.001), and family type (t=-2.484, p=.013). 4) Among the categories, there were significant correlations between all 8 categories and significant correlation between 'Acting tips' and 'First aid' (r=.808, p<.001), 'Acting tips' and 'Coping ability' (r=.956, p<.001), and 'First aid' and 'Coping ability' (r=.946, p<.001). Conclusion: The findings indicate a need for programs to improve the coping ability of elementary school students in emergency situations.

• 한국레이저가공학회지
• /
• 제10권3호
• /
• pp.25-32
• /
• 2007

The effect of welding speed on the weldability, microstructures, hardness, tensile property of Nd:YAG laser welding joint in 600MPa grade precipitation hardening high strength steel was investigated. A shielding gas was not used, and bead-on-plate welding was performed using various welding speeds at a power of 3.5kW. Porosity in the joints occurred at 1.8m/min, but were not observed over the welding speed of 2.1m/min. However, spatter occurred over the welding speed of 6.6m/min. The hardness was the highest at heat affected zone(HAZ) near fusion zone(FZ), and was decreased on approaching to the base metal. The maximum hardness increased with increasing welding speed. The microstructure of FZ was composed of coarse grain boundary ferrite and bainite(upper) but the HAZ near the FZ contained bainite(Lower) and fine ferrite at a low welding speed. With increasing welding speed, ferrite at the FZ and the HAZ became finely and upper binite changed to lower bainite. In a perpendicular tensile test to the weld line, all specimens were fractured at the base metal, and the tensile strength and the yield strength of joints was equal to those of raw material. Elongation was found to be lower than that of the raw material.

• 수산해양기술연구
• /
• 제28권4호
• /
• pp.418-429
• /
• 1992

Recently, many researchers make a great effort to develop high efficient marine diesel engines using low grade heavy oil, and also study substitution fuel oil for engines and boilers. In case of Fisheries Vessels, we need to know that fish oil can be substituted for fuel oil. Therefore, it is studied that evaporation, ignition and combustion phenomena of the single droplet of fish oils (i.e., Sardine fish oil, File fish oil and Alaska pollac oil) on heated plane surface to evaluate appropriateness as substitution oil. Methanol and light oil are tested simultaneously to help the evaluation on these Fish oils. The results are summarized as follows: 1. The type of evaporation and combustion is spherical evaporation in case of methanol and light oil. And fish oil blended with light oil was finished after spherical evaporation happen when high temperature. 2. Ignition of Pure fish oil was shorter than that of fish oil blended with light oil. 3. Heat transferred to droplet could make qualitative comparison by contact diameter of droplet with hot surface as time changes. Life time of droplet according to the change of heated surface temperature was greatly influenced by droplet contact condition on the heated surface. 4. As far as combustion phenomena was concerned, apparent diameter of the fish oil droplet increased after ignition and decreased suddenly by internal boiling of droplet. 5. Three fish oils had similar phenomena on the evaporation, ignition and combustion. 6. Evaporation and combustion feature of fish oil could not be shown by coefficient of evaporation velocity of droplet and coefficient of combustion velocity of droplet.

• 한국수산과학회지
• /
• 제52권6호
• /
• pp.562-570
• /
• 2019

To develop natural-tasting fish paste from the pufferfish Lagocephalus wheeleri, steamed pufferfish paste (SPP) was prepared and its optimal processing conditions, quality metrics, and shelf-life characteristics were examined. SPP was produced by thawing golden threadfin Nemipterus virgatus surimi (FA grade), then adding 10% unwashed pufferfish surimi (PS), 1.5% salt, 8.0% wheat starch, 0.25% calcium carbonate, 0.25% sugar, 0.75% sorbitol, 0.25% polyphosphate, and 12.0% pufferfish hot-water extract (Brix 10°). The meat was ground with a Stephan mixer, molded at low temperature (18℃, 10 h), vacuum packed in a laminated plastic film bag, heat treated with hot water (95℃, 50 min), and cooled. As the amount of PS added increased, the whiteness, gel strength, and shear strength of the SPP decreased slightly. However, the SPP folding test showed no deterioration in the texture. In the sensory evaluation, the SPP received a higher rating for taste, smell, and overall taste than commercial Japanese pufferfish Kamaboko. The total amino acid content of the SPP was 10,262.6 mg/100 g; the major amino acids were aspartic acid, glutamic acid, alanine, valine, leucine, lysine, and arginine. The free amino acid content was 133.0 mg/100 g; the major amino acids were taurine, glutamic acid, glycine, alanine, cystine, and lysine.

• 한국의류학회지
• /
• 제29권12호
• /
• pp.1527-1534
• /
• 2005

본 연구는 아동의 체온조절반응의 특징에 성장환경이 어떠한 영향을 미치는가를 명확히 하기 위해, 한국아동(K group)과 일본아동(J group)의 체온조절반응을 검토하였다. 팬츠 착용의 피험자는 중립환경 $(28.5^{\circ}C)$에서 1시간, 추운환경$(22^{\circ}C)$ 또는 더운환경$(37^{\circ}C)$으로 옮겨져 1시간 동안의 체온조절반응이 검토되었다. 그 결과, 직장온은 환경온이 높아짐에 따라 약간 높아졌으며, K group의 직장온이 J group보다 약간 높았다. 추운환경에서의 손과 발의 피부온은 현저히 저하되었으며, J group보다 K group에서 더 현저히 나타났다. 그리고, 두 group의 절대 국소 증발량은 환경온 $22^{\circ}C$와 $28.5^{\circ}C$에서 비슷한 분포를 나타내는 반면, 환경온 $37^{\circ}C$에서는 J group은 몸 전체에서 발한을 나타냈으나 K group은 사지보다 몸통부위의 발한량이 많았다. 맥박은 환경온의 상승에 따라 높아졌으며, J group의 맥박이 K group보다 더 높았다.

• 한국가금학회지
• /
• 제39권3호
• /
• pp.183-193
• /
• 2012

본 연구는 육계 출하 2일 전부터 전해물질을 급여한 후 출하 직전에 혈액을 채취하고, 출하 시 고온 수송 스트레스를 받게 한 후 닭의 혈액을 채취하였으며, 도계 후 닭고기 도체 특성을 조사하여 전해질 종류($NaHCO_3$, KCl, NaCl) 및 급여수준에 따라 혈액 및 도체 특성을 구명하기 위하여 실시하였다. 음수량의 변화에서는 고온 하에서 육계를 출하시 대조구에 비하여 처리 2구를 제외하고 전해물질을 급여한 모든 처리구에서 약간씩 증가하는 경향을 나타내었으며, 특히 처리 4구에서 음수량이 가장 높았다. 계분의 수분 함량은 처리 5구에서 87.13%로 가장 높은 수분량을 나타내었고 대조구에서 수분 함량이 가장 낮았다. 조지방과 조단백질은 대조구에서 가장 높은 함량을 나타내었다. 닭고기 도체의 pH 변화는 대조구에 비하여 전해질을 급여한 모든 처리구에서 증가하였고, 특히 처리 3구에서 가장 높은 pH 값을 나타내었다. 닭고기 $1^+$ 등급 출현율은 대조구가 33.3%인 반면에 처리 3, 4구는 60%, 처리5구는 83.3%으로 고온 스트레스 하에서 전해질 물질을 충분히 급여함에 따라 닭고기 $1^+$ 등급 출현율을 증가시켰다. 닭고기의 PSE 발생율도 대조구는 50%를 나타내었으나, 처리 5구는 13.3%를 나타내어 매우 낮은 수준을 나타내었다. 육계를 출하 시 고온스트레스에 대한 육계의 혈액 중 corticosterone의 변화는 출하 전보다 출하 후 측정값이 상승하였으나, 처리 3구를 제외하고 대조구에 비하여 출하 전과 출하 후의 차이가 적은 것으로 나타났다. ACTH에 대한 변화에서도 출하 전보다 출하 후에 모든 처리구에서 상승하였으며, 출하 후에 처리 5구에서 가장 낮은 ACTH의 함량을 나타내었고, 출하 전 후 차이값도 가장 낮게 나타났다. 혈액의 $pCO_2$ 분압은 출하 전보다 고온 스트레스를 받은 후 전체적으로 낮아졌으며, 출하 전 후의 차이 값은 대조구에서 가장 높았고, 처리 4, 5구에서 대체적으로 낮은 차이 값을 나타내었다. 혈액의 $pO_2$ 분압은 출하 전 후에서 처리별로 일정한 경향을 나타내지 않았다. 이상의 결과로 고온에서 육계 출하 시 수송 스트레스를 저하시키고 닭고기의 품질을 높이기 위하여 전해 물질($NaHCO_3$, NaCl, KCl)을 고루 혼합한 처리 4, 5구가 비교적 우수한 것으로 나타났다.