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Analysis of K-12 Science Textbooks Related to 'States of Water', 'State Change of Water', and 'Conditions of State Change' (물의 상태, 상태변화 및 그 조건에 대한 유치원, 초등, 중등 과학 교재의 내용 분석)

  • Paik, Seong-Hey;Park, Jae-Won;Park, Jin-Ok;Im, Myoung-Hyuk;Ko, Young-Mi;Cho, Boo-Kyung;Kim, Hyo-Nam
    • Journal of The Korean Association For Science Education
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    • v.22 no.2
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    • pp.215-229
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    • 2002
  • This study is to analyze the contents related to 'state of water', 'state change of water', and 'conditions of state change' in K-12 science textbooks. For this, we analyzed textbooks based on the 5th kindergarten curriculum, the 6th elementary school science curriculum and the 6th middle school science curriculum. Findings show that some of the contents are designed well by topical sequencing or by spiral sequencing. But others have some problems based on topical sequencing and spiral sequencing. Generally, the contents are represented in the order of Perception of phenomena with senses level, Macroscopic understanding level, Understanding of scientific term level, Microscopic understanding level by grade. But the state change contents related to solidification and melting, and conditions of state change contents related to heat, temperature, wind, and humidity are not represented in the level of Microscopic understanding. The contents of state change and conditions related to heat and wind are not represented in the level of scientific term also.

Characteristics of Sn-Ag-Cu-In Solder Alloys Incorporating Low Ag Content (소량의 Ag를 함유하는 Sn-Ag-Cu-In계 솔더 재료의 특성 분석)

  • Yu, A-Mi;Lee, Jong-Hyun;Lee, Chang-Woo;Kim, Mok-Soon;Kim, Jeong-Han
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.18-18
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    • 2007
  • 지난 수년 동안 Sn-3.0Ag-0.5Cu 합금은 전자산업의 표준 무연솔더 조성으로 전자제품의 제작에 사용되어져 왔으며, 그 신뢰성도 충분히 검증되어 대표적인 무연 솔더 조성으로의 입지를 굳혀왔다. 그러나 전자제품의 mobile화에 따른 내충격 신뢰성에 대한 요구와 최근의 급격한 Ag 가격의 상승은 Ag 함량의 축소에 의한 원가절감을 요청하게 되었으며, 이에 따라 소량의 Ag를 함유하는 솔더 조성 개발에 대한 연구가 산업 현장을 중심으로 절실히 요청되고 있다. Sn-Ag-Cu의 3원계 함긍에서 Ag는 합금의 융점을 낮추고, 강도와 같은 합금의 기계적 특성을 증가시키는 한편, 모재에 대한 합금의 젖음성을 향상시키는데 필수적인 원소로 인식되고 있다. 따라서 Sn-Ag-Cu의 3원계 함금에서 Ag의 함량을 감소시키게 되면, 합금액 액상선 온도와 고상선 온도가 벌어져 pasty range(또는 mush zone)가 증가하게 되고, wettability도 감소하게 되어 솔더 합금으로서의 요구 특성을 많이 상실하게 된다. 또한 Ag 함량을 감소시키게 되면 합금의 elongation이 향상되면서 내 impact 수명이 향상되는 효과를 볼 수 있으나, 합금의 creep 특성 및 기계적인 강도는 감소하면서 열싸이클링 수명은 감소하는 경향을 나타내게 된다. 따라서 솔더 합금의 내 impact 수명과 열싸이클링 수명을 동시에 만족시키지 위해서는 Ag 함량을 최적화하기 위한 고려가 필요하며, 합금원소에 대한 연구가 요청된다고 하겠다. 한편 Ag의 함량을 3wt.% 이상으로 첨가할 경우에도 비교적 느린 응고 속도에서는 조대한 판상의 $Ag_3Sn$ 상을 형성하는 경향이 있어 외관 물량을 야기 시킬 가능성이 매우 커지는 현상도 보고되고 있다. 따라서 Ag의 첨가량을 최적화 하면서 솔더 재료로서의 특성을 계속적으로 유지하기 위해서는 제 4 원소의 함유가 필수적이라고 할 수 있다. 본 연구에서는 Sn-Ag-Cu계에 첨부하는 제 4원소로서 In을 선택하였다. 비록 In은 Ag보다 고가이기 때문에 산업적인 적용을 위한 솔더 합금 원소로는 거의 각광받지 못했으나, 본 연구의 결과로는 In은 매우 소량 첨가할 경우에도 Sn-Ag-Cu계 합금, 특히 소량의 Ag를 함유하는 Sn-Ag-Cu계 합금의 wettabilty와 기계적 특성 향상에 매우 효과적임을 알 수 있었다. 결론적으로 본 연구를 통해 구현된 Sn-Ag-Cu-In계 최적 솔더 조성의 경우 Sn-3.0Ag-0.5Cu의 표준 조성에 비하여 약 18%의 원자재 가격 절감을 도모할 수 있을 것으로 예상되는 한편. Sn-3.0Ag-0.5Cu에 유사하거나 우수한 wettability 특성을 나타내었고. Sn-1.0Ag-0.5Cu 또는 Sn-l.2Ag-0.5Cu-0.05Ni 조성보다는 월등히 우수한 wettability 특성을 나타내었다. 더구나 Sn-Ag-Cu-In계 최적 솔더 조성은 합금의 강도 저하는 최소화 시키면서 합금의 elongation은 극적으로 향상시켜 합금의 toughness 값이 매우 우수한 특성을 가짐을 알 수 있었다. 이렇게 우수한 toughness 값은 솔더 조인트의 대표적 신뢰성 요구 특성인 열싸이클링 수명과 내 impact 수명을 동시에 향상시킬 수 있을 것으로 예상된다. 요컨대 본 연구를 통해 구현된 Sn-Ag-Cu-In계 솔더 조성은 최적 솔더 조성에서 요구되는 4가지 인자, 즉, 저렴한 원재료 가격, 우수한 wettability 특성, 합금 자체의 높은 toughness, 안정하고 낮은 성장 속도의 계면 반응층 생성을 모두 만족시키는 특징을 가짐으로서 기존 무연솔더 조성의 새로운 대안으로 자리 잡을 것으로 기대된다.

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Comparative Analysis of Delivery Management in Various Medical Facilities (의료기관별 분만관리 양상의 비교 분석)

  • Park, Jung-Han;You, Young-Sook;Kim, Jang-Rak
    • Journal of Preventive Medicine and Public Health
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    • v.22 no.4 s.28
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    • pp.555-577
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    • 1989
  • This study was conducted to compare the delivery management including laboratory tests, medication and surgical procedures for the delivery in various medical facilities. Two university hospitals, two general hospitals, three hospitals, two private obstetric clinics, and two midwifery clinics in a large city were selected as they permitted the investigators to abstract the required data from the medical and accounting records. The total number of deliveries occurred at these 11 facilities between 15 January and 15 February, 1989 was 789 among which 606(76.8%) were vaginal deliveries and 183 (23.3%) were C-sections. For the normal vaginal deliveries, CBC, Hb/Hct level, blood typing, VDRL, hepatitis B antigen and antibody, and urinalysis were routinely done except the private clinics and midwifery clinics which did not test for hepatitis B and Hb/Hct level at all. In one university hospital ultrasonography was performed in 71.4% of the mothers and in one general hospital liver function test was done in 76.7% of the mothers. For the C-section, chest X-ray, bleeding/clotting time and liver function test were routinely done in addition to the routine tests for the normal vaginal deliveries. Episiotomy was performed in 97.2% of the vaginal deliveries. The type and duration of fluid infused and antibiotics administered showed a wide variation among the medical facilities. In one university hospital antibiotics was not administered after C-section at all while in the general hospitals and hospitals one or two antibiotics were administered for one week on the average. In one private clinic one pint of whole blood was transfused routinely. A wide variation was observed among the medical facilities in the use of vitamin, hemostatics, oxytocics, antipyreptics, analgesics, anti-inflammatory agents. sedatives. digestives. stool softeners. antihistamines. and diuretics. Mean hospital day for the normal vaginal deliveries of primipara was 2.6 days with little variation except one hospital with 3.5 days. Mean hospital day for the C-section of primipara was 7.5 days and that of multipara was 7.6 days and it ranged between 6.5 days and 9.4 days. Average hospital fee for a normal vaginal delivery without the medical insurance coverage was 182,100 Won for the primipara and 167,300 Won for the multipara. In case of the primipara covered by the medical insurance a mother paid 82,400 Won and a multiparous mother paid 75,600 Won. Average hospital fee for a C-section without the medical insurance was 946,500 Won for the primipara and 753,800 Won for the multipara. In case of the primipara covered by the medical insurance a mother paid 256,200 Won and a multiparous mother paid 253,700 Won. Average hospital fee for a normal vaginal delivery in the university hospitals showed a remarkable difference, 268,000 Won vs 350,000 Won, as well as for the C-section. A wide variation in the laboratory tests performed for a normal vaginal delivery and a C-section as well as in the medication and hospital days brought about a big difference in the hospital fee and some hospitals were practicing the case payment system. Thus, standardization of the medical care to a certain level is warranted for the provision of adequate medical care for delivery.

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Clinical Study of Group B β-Hemolytic Streptococcal Meningitis (B군 연쇄상구균 뇌막염에 대한 임상적 고찰)

  • Lee, Seo-Young;You, Sou-Jeong;Kim, Deok-Soo;Ko, Tae-Sung
    • Clinical and Experimental Pediatrics
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    • v.46 no.12
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    • pp.1224-1229
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    • 2003
  • Purpose : Bacterial meningitis is a serious disease, especially in the neonatal period, and it carries a significant degree of mortality and morbidity. Group B streptococcus(GBS) is a common cause of neonatal bacterial meningitis. The purpose of this study was to evaluate the clinical manifestations, treatment results and complications of GBS meningitis. Methods : We analyzed 29 cases retrospectively who had been admitted to the pediatric ward or NICU in Asan Medical Center from May 1990 to January 2002. They had proven GBS in culture or latex agglutination test in CSF. Results : The male to female ratio was 1 : 1.9. There were two cases of early onset type and 27 cases of late onset type. All cases had normal birth weight with full term at delivery. The perinatal predisposing factors were premature rupture of membrane(two cases), and maternal colonization(two cases). The most common presenting symptoms were fever and irritability. Associated diseases were GBS sepsis(21 cases). There was relatively high sensitivity to penicillin derivatives. There were abnormal brain CT or MRI findings in 16 cases(64%), such as infarction, encephalomalatic change, effusion, hydrocephalus, hemorrhage and abscess. The intensive care unit admission rate and the incidence of DIC were higher in the group with complications. Two cases were discharged against advice. Conclusion : We recommend early detection and active treatment in Group B streptococcal meningitis to improve the prognosis.

Analysis of Methoxyfenozide and Bentazone in Plant with HPLC by pH-Adjusted Liquid-liquid Partition Cleanup (pH조절 분배추출에 의한 식물체 중 Methoxyfenozide와 Bentazone의 HPLC 분석)

  • Lo, Seog-Cho;Hwang, Cheol-Hwan;Yoo, Ki-Yong;Han, Seong-Soo
    • Korean Journal of Environmental Agriculture
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    • v.26 no.3
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    • pp.246-253
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    • 2007
  • This study was performed to enhance the cleanup efficiency of methoxyfenozide and bentazone by pH adjustment in the course of liquid-liquid partition and to develop an optimum analytical conditions using HPLC coupled with DAD for two matrices, brown rice and rice straw. Preparation procedure of brown rice sample was "extraction${\rightarrow}$coagulation${\rightarrow}$liquid-liquid partition$\rightarrow$-florisil C.C", and this procedure was samely applied to two compounds. In rice straw, preparation procedure of methoxyfenozide sample was "extraction$\rightarrow$-alkalization$\rightarrow$liquid-liquid extraction$\rightarrow$coagulation$\rightarrow$florisil C.C", and in the case of bentazone, "extraction$\rightarrow$alkalization$\rightarrow$liquid-liquid partition$\rightarrow$acidification$\rightarrow$liquid-liquid extraction$\rightarrow$florisil C.C". All these purified samples were redissolved in the mobile phases, acetonitile : 20 mM sodium acetate (75:25, v/v) for methoxyfenozide and acetonitrile : 75 mM sodium acetate, pH 6.0 (40:60, v/v) for bentazone. Recoveries of methoxyfenozide analysis in brown rice and rice straw were 83.5-97.4 and 86.4-97.3%, and detection limits were 0.02 and 0.04 mg/kg, respectively. Recoveries of bentazone in brown rice and rice straw were 86.8-101.9 and 88.3-94.5% and detection limits were 0.005 and 0.01 mg/kg, respectively. This methods seem to be usefully applied to the residue analysis of two compounds in the view of producing stable analytical condition and fair reproducibility.

Studies on Stability for the Quality of Ginseng Products -5. Improvement of Physical Properties on Moisture Sorption of Spray Dried Red Ginseng Extract Powder- (인삼제품(人蔘製品)의 품질안정성(品質安定性)에 관한 연구(硏究) -5. 홍삼정분(紅蔘精粉)의 흡습물성(吸濕物性) 개선(改善)-)

  • Choi, Jin-Ho;Byun, Dae-Seok;Ro, Jae-Il;Park, Kil-Dong;Sung, Hyun-Soon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.13 no.3
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    • pp.251-258
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    • 1984
  • In order to improve the physical properties on moisture sorption of spray dried red ginseng extract powder (SD-RGEP), the various additives and coating agents were treated, and solubility, sedimentation rate and storage stability of RGEPs treated were investigated. For the moisture-proofing, additive itself was effective in the order casein>dextrin>starch>avicell, but RGEPs treated with additives were effective in the order cord oil+tween-40>starch>casein. But there was no significant difference between RGEP treated less than 1% additive and the moisture-proofing. The coating effect of AEA and CAP on RGEP could not be recognized for the moisture-proofing, whereas that of HPC, corn oil, lecithin and HPC+corn oil was proved to be very effective for the moisture-proofing of RGEP. Also it is required to control the initial moisture content of RGEP. The sedimentation rate of RGEP nontreated was 65.1 seconds, whereas that of RGEPs coated with 1% HPC, 1% corn oil, 1% lecithin and 1% HPC+0.5% corn oil was in the range of 96.2 to 114.3 seconds. The sedimentation rate of RGEPs coated was 1.5 to 1.8 times higher than that of RGEP nontreated, and there was significant difference between solubility and sedimentation rate. Therefore it was no matter for the keeping quality. The sorption rates of RGEPs coated with lecithin $(0.5{\sim}1.0%$), corn oil(0.8%) and cellulose acetate (0.8%) were ranged 54 to 56%, 51 to 55% and 52 to 54%, respectively, and it is found that the moisture-proofing effect of RGEPs coated was about 2 times higher than that of RGEP nontreated. From the result of storage experiment during 3 months under the maltreated condition of $48{\pm}2^{\circ}C$, 75% RH, the moisture sorption of RGEPs coated with corn oil$(0.5{\sim}1.0%$), cellulose acetate(DES, $0.5{\sim}0.8%$) and lecithin (DES, 1.0%) was not at all observed. Therefore it is considered that the circulating period of RGEPs coated with these coating agents could to give more than 3 years.

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Quality Characteristics of Sea Tangle Single Cell Detritus (SCD) Manufactured by Vibrio sp. Isolated from Batillus cornutus (소라에서 분리한 Vibrio균으로 제조한 다시마 Single Cell Detritus(SCD)의 품질특성)

  • Bang, Sang-Jin;Shin, Il-Shik;Kim, Sang-Moo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.35 no.5
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    • pp.606-612
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    • 2006
  • Obtaining powder form of seaweed is essential for the use of seaweed as a food additive. The deterioration of seaweed caused by high temperatures during homogenization and powder processing is a serious problem and limits the use of seaweed as a food or pharmaceutical ingredient. Furthermore, many powder particles are not fluidized very well because of the interaction between particles. In order to solve this problem, sea tangle was hydrolyzed to a level of single cell detritus (SCD) by Vibrio sp., isolated from Batillus cornutus. with strong hydrolytic activity. The crude protein and amino acid contents of sea tangle SCD were higher than those of the powder, whereas the reverse was true for ash content. Sea tangle powder contained more mineral than its SCD, whereas total amino acid content was 5 times more in SCD than in power. The anticancer activities of sea tangle SCD and powder were 31.20 and 29.07%, respectively, with no significant difference (p<0.05), but about 15% higher than that of the control. The ACE inhibitory activity of the sea tangle powder, 39.31%, was higher than the 26.07% of the SCD. The antithrombin activity of the sea tangle powder, 55.3 seconds, was higher than the 34.5 seconds of the SCD. Moreover, there was no antioxidative and ischemic activities in both tile sea tangle powder and SCD.

Microstructures and Electrochemical Properties of Si-M (M : Cr, Ni) as Alloy Anode for Li Secondary Batteries (리튬이차전지용 Si-M (M : Cr, Ni) 합금 음극의 미세구조와 전기화학적 특성)

  • Lee, Sung-Hyun;Sung, Jewook;Kim, Sung-Soo
    • Journal of the Korean Electrochemical Society
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    • v.18 no.2
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    • pp.68-74
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    • 2015
  • To compare the microstructure and electrochemical properties between two binary alloys (Cr-Si, Ni-Si), two composition of binary alloys with the same capacity were selected using phase-diagram and prepared by matrix-stabilization method to suppress the volume expansion of Si by inactive-matrix. Master alloys were made by Arc-melting followed by fine structured ribbon sample preparation by Rapid Solidification Process (RSP, Melt-spinning method) under the same conditions. Also powder samples were produced by wet grinding for X-Ray Diffraction (XRD) and electrochemical measurements. As predicted from the phase diagram, only active-Si and inactive-matrix ($CrSi_2$, $NiSi_2$) were detected. The results of Scanning Electron Microscope (SEM) and Transmission Electron Microscopy - Energy Dispersive X-ray Spectroscopy (TEM-EDS) show that Cr-Si alloy has finer microstructure than Ni-Si alloy, which was also predictable through phase diagram. The electrochemical properties related to microstructure were evaluated by coin type full- and half-cells. Separately, self-designed test-cells were used to measure the volume expansion of Si during reaction. Volume expansion of Cr-Si alloy electrode with finer microstructure was suppressed significantly and improved in cycle capability, in comparison Ni-Si alloy with coarse microstructure. From these, we could infer the correlation of microstructure, volume expansion and electrochemical degradation and these properties might be predicted by phase diagram.

Optimization of Heating and Addition of Water, Oil and Dextrin for Uncompressed SPI Tofu Preparation (비압착식 SPI 두부의 제조를 위한 가열 및 수분, 기름, 덱스트린 첨가의 최적화)

  • Kim, Woo-Jung;Ku, Kyung-Hyung
    • Korean Journal of Food Science and Technology
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    • v.26 no.1
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    • pp.37-43
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    • 1994
  • Optimization study was conducted for preparation of uncompressed soy protein isolate(SPI) tofu in the aspects of water addition ratio, second heating temperature and amounts of oil and dextrin added. The SPI tofu was prepared without compression step with SPI-oil-dextrin mixture and $CaSO_4-GDL$ mixed coagulants. The data were statistically analyzed by multiple regresstion and response surface methodology(RSM). Addition of dextrin increased the hardness of tofu, particularly for the second heating at $85^{\circ}C$ and 8 times of water to SPI. RSM figure showed that the effect of dextrin on hardness became to be less as the heating temperature increased. The hardness increase effect was no significant except addition of 25% oil and 8 times of water and second heating at $85^{\circ}C$. The addition of 25% oil and $10{\sim}15%$ dextrin and second heating at $90^{\circ}C$ for $45{\sim}60$ minutes resulted hardness and cohesive tofu. The optimal method proposed for uncompressed SPI tofu on the basis of textural and sensory properties was first heating of homogenized SPI-oil-dextrin(100:25:15) with addition of 8 times of water(on the basis of SPI) at $100^{\circ}C$ for 6 minutes, cooling to $40^{\circ}C$, additon of mixed coagulants of $CaSO_{4}-GDL$(0.07 g, 0.0075 g/SPI) and second heating at $90^{\circ}C$ for 45 minutes.

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Comparison of Soybean Varieties for Yield, Chemical and Sensory Properties of Soybean Curds (콩 품종에 따른 두부의 수율 및 화학적, 관능적 특성의 비교)

  • Chang, Cheon-Il;Lee, Jung-Kun;Ku, Kyung-Hyung;Kim, Woo-Jung
    • Korean Journal of Food Science and Technology
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    • v.22 no.4
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    • pp.439-444
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    • 1990
  • Fourteen varieties of soybeans grown in Korea were investigated for their chemical composition, yields and organoleptic properties of soybean curd. The soybean curd was prepared by soaking, grinding and heating of soybeans followed by filtration, coagulation with $CaSO_4$ and pressing. The proximate analysis showed that soybean curd had the moisture content of $75.0{\sim}82.0%\;and\;48.6{\sim}56.1%\;protein,\;14.8{\sim}40.4%\;lipids\;and\;6.4{\sim}26.8%$ carbohydrate by dry weight basis. The yield of volume total solids and protein from 100g of soybeans were $182.2{\sim}227.5cm^3,\;42.65{\sim}55.60%\;and\; 57.90{\sim}76.50%$, respectively. Among the 14 varieties, the highest volume yield was obtained from Suwon-141 which has the highest contents of moisture, carbohydrate and the lowest in lipids of soybean curd. The curd prepared with Baegun and Jangyeob contained relatively low values in moisture, protein and carbohydrate and yielded the lowest in volume yield. Therefor moisture, protein and carbohydrate contents in soybean curd affected greatly on volume yield. The organoleptic properties of odor and taste couldn't find any significant relationship with chemical composition of soybean curd eventhough there were some difference in their intensities among varieties.

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