• Title/Summary/Keyword: secondary materials

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Mössbauer Study on the Variation in Magnetic Properties of CuO Induced by 57Fe Addition (57Fe 이온이 CuO에 미치는 효과에 관한 Mössbauer 분광 연구)

  • Park, Jae-Yun;Kim, Kwang-Joo
    • Journal of the Korean Magnetics Society
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    • v.19 no.3
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    • pp.113-119
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    • 2009
  • $^{57}Fe_xCu_{1-x}O$(x = 0.0, 0.02) powders were prepared by sol-gel method and their crystallographic and magnetic hyperfine properties have been studied using X-ray diffraction and $M{\ddot{o}}ssbauer$ spectroscopy (MS). The crystal structure of the samples is found to be monoclinic without any secondary phases and their lattice parameters increase with increasing annealing temperature ($T_A$), which is attributed to an increase in oxygen-vacancy content. MS measurements at room temperature indicate that $Fe^{3+}$ ions substitute $Cu^{2+}$ sites and ferromagnetic phase grow with increasing $T_A$. Magnetic hyperfine and quadrupole interactions of $^{57}Fe_{0.02}Cu_{0.98}O$ ($T_A=500^{\circ}C$) in the antiferromagnetic state at 17 K have been studied, yielding the following results: $H_{hf}=426.94\;kOe$, ${\Delta}E_Q=-3.67\;mm/s$, I.S.=0.32 mm/s, ${\theta}=65^{\circ}$, ${\phi}=0^{\circ}$, and ${\eta}=0.6$.

A Study on the Effects of Bee Venom Aqua-Acupuncture on Pain related Neuronal activity in the Spinal Cord (봉독약침(蜂毒藥鍼)이 척수내(脊髓內) 통증관련(痛症關聯) 신경세포(神經細胞)의 활성(活性)에 미치는 영향(影響))

  • Jeong, Sun-Hee;Lee, Jae-Dong;Koh, Hyung-Kyun;Ahn, Byoung-Choul;Choi, Do-Young;Park, Dong-Suk
    • Journal of Acupuncture Research
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    • v.17 no.2
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    • pp.153-168
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    • 2000
  • Introduction : In spite of the use of Bee Venom aqua-acupuncture in the clinics, the scientific evaluation on effects is not enough. Bee Venom aqua-acupuncture is used according to the stimulation of acupuncture point and the chemical effects of Bee Venom. The aims of this study is to investigate the analgegic effects of the Bee Venom aqua-acupuncture, through the change of writhing reflex and the change of c-fos in secondary neurons in the spinal cord. Materials and Methods : Pain animal model was used acetic acid method. The changes of writhing reflex of the mice which were derived pain by injecting acetic acid into the abdomen, after stimulating Bee Venom aqua-acupuncture on Chungwan(CV12) were measured. We used Fos immunohistochemical technique to study the neuronal activity in the spinal cord. Results : 1. Expression of c-fos in superficial dorsal horn(SDH), nucleus proprius(NP) and neck of dorsal hom(N) on 6~9th thoracic spine decreased significantly at $2.5{\times}10-4$g/kg Bee Venom aqua-acupuncture, compared with saline-acetic acid group. 2. The numeral change of Fos-LI neurons on the NP, N, and ventral gray(V) on 6-9th thoracic spine, SDH on 9-11th thoracic spine, and SDH and V on 11~13th thoracic spine decreased significantly at Chungwan(CV12) Bee Venom aqua-acupuncture, compared with saline-acetic acid group. 3. The correlation between the numbers of writhing refleax and Fos-LI neurons in T6-13 segment was statistically statistically significant at Chungwan(CV12) Bee Venom aqua-acupuncture. Conclusion : This study shows that the Bee Venom aqua-acupuncture on Chungwan(CV12) decreases the numbers of Fos-LI neurons. As the analgegic effects of Bee Venom aqua-acupuncture is recognized. Bee Venom aqua-acupuncture treatment is expected for pain modulation. In order to use it in many ways, more researches are needed for the dose and stability of Bee Venom aqua-acupuncture.

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Micromorphology and Chemical Composition of a Sialolith in the Submandibular Gland Duct (악하선 내 타석의 미세형상 및 화학적 조성)

  • Im, Yeong-Gwan;Song, Ho-Jun;Kim, Byung-Gook
    • Journal of Oral Medicine and Pain
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    • v.36 no.3
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    • pp.161-167
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    • 2011
  • Sialolith is one of the most common pathologic conditions found in the salivary glands. The mechanisms responsible for the formation of sialoliths have not been elucidated so far. In this article, the chemical composition and micromorphology of a sialolith of a 58-year old female patient suffering from chronic sialoadenitis of the submandibular gland was analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). In a SEM evaluation, the highly mineralized amorphous core surrounded by lamellar and concentric structures was revealed, however no foreign body, organic material, or signs of microorganism were observed in the core of the sialolith. EDX analysis showed the central core was composed of only Ca, O and P, and that a high level of C was detected near the central area as well. These results indicated that the inorganic composition of the sialolith was hydroxyapatite crystals, and that inorganic and organic substances existed around the central cores. This study suggests that the sialolith was composed mainly of hydroxyapatite crystals and the formation of the nucleus of the sialolith in the submandibular gland duct was secondary to sialadenitis, which favors the growth of an inorganic crystalline nucleus.

EFFECT OF TAPER AND SURFACE AREA OF INNER CROWN ON THE RETENTIVE FORCE OF ELECTROFORMED OUTER CROWN (전기성형술로 제작된 외관의 유지력에 내관의 축면경사도와 표면적이 미치는 영향)

  • Kang Wan-Keun;Lim Jang-Seop;Jeon Young-Chan;Jeong Chang-Mo;Jeong Hee-Chan
    • The Journal of Korean Academy of Prosthodontics
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    • v.44 no.2
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    • pp.165-173
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    • 2006
  • Purpose: With gold electroforming system fir the double crown, the secondary crown is electroformed directly onto the primary crown. An even thick layer of high precision can be acquired. It is thought that the retention of electroformed outer crown is primarily acquired by the adhesive force (surface tension) through the saliva which is interposed between precisely fitted inner and outer crown. The purpose of this study was to investigate the effect of taper and surface area of inner crown on the retentive force of electroformed outer crown according to the presence of saliva. Materials and methods: 32 titanium inner crowns with cervical diameter of 8 mm and cone angles of 0, 2, 4, 6 degrees, which had same surface area by regulated height, were machined on a lathe. Another 32 titanium inner crowns with cone angles of 0, 2, 4, 6 degrees, which had doubled surface area by increased cervical diameter. were fabricated. Eight specimens of each group, for a total of 64 titanium inner crowns, were prepared. The electroformed outer crowns were fabricated directly on the inner crowns by using electroforming machine(GAMMAT free, Gramm Technik, Germany). The tertiary frameworks were waxed-up on the electroformed outer crown and cast using nonprecious alloy($Rexillium^(R)III,\;Jeneric^(R)/Pentronh^(R)$ Inc., USA). The cast metal frameworks were sandblasted with alubimium oxides and cemented using resin cement(Superbond C&B, Sun Medical Co., Japan) over the electroformed copings of each specimen. Then, artificial saliva($Taliva^(R)$, Halim Pharm. Co., Korea) was sprayed between the inner and outer crown, and they were connected under 5 kg force. The retentive force was measured by the universal testing machine(Tinius Olsen 1000, Tinius Olsen, USA) with a cross-head speed of 66.67 mm/sec. The direction of cross-head travel was exactly aligned with the path of removal of the respective specimens. This measurement procedures for retentive force of electroformed outer crown with artificial saliva were repeated in the same way without presence of artificial saliva. Results and Conclusion: The following conclusions were drawn: 1. The retentive force of electroformed outer crown was decreased according to increased taper of inner crown(P<.05). 2. The retentive force of electroformed outer crown showed no significant differences according to surface area and the presence of artificial saliva(P>.05).

Fixed prosthodontic rehabilitation of maxillary posterior teeth using functionally generated path technique and intraoral digital scan: Case report (Functionally generated path technique 및 구내 디지털 스캔을 이용한 상악 구치부의 고정성 보철 수복 증례)

  • Kim, Sung-Ho;Lee, Jonghyuk;Choi, Yu-Sung
    • The Journal of Korean Academy of Prosthodontics
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    • v.58 no.3
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    • pp.228-238
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    • 2020
  • In order to deliver fixed partial denture to a patient successfully, dentist must take into many considerations beforehand. Patient's occlusal pattern should be fully understood before delivering any type of prosthesis, whether it's canine guidance or group function occlusion. In order to do so, movement of mandible should be recorded precisely. Introduced by Meyers in 1933, functionally generated path technique (FGP) has been successfully used to record mandibular movement with various materials, such as wax, and utilize it in fabricating precise prosthesis. In the following cases, patients showed secondary caries or endodontic-periodontic lesion on maxillary molars. Root canal treatment and subgingival curettage were done for each patient. Since the long term prognosis of each tooth was questionable, lateral force should be minimized. In order to do so, FGP technique was used to record mandibular movements precisely. Instead of using conventional plaster impression, intra-oral scanning of wax tracing was done to fabricate prosthesis efficiently. After delivery of fixed partial denture, favorable outcome was obtained.

A Case Study on the Changes in Teaching Professionalism of Beginning Science-gifted Education Teachers through Mentoring in the Aspects of Pedagogical Content Knowledge (멘토링을 통한 초임 과학영재교육 담당교사들의 PCK 측면에서의 수업 전문성 변화에 대한 사례연구)

  • Noh, Taehee;Lee, Jooseok;Kang, Hunsik
    • Journal of The Korean Association For Science Education
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    • v.32 no.7
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    • pp.1187-1203
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    • 2012
  • This study investigated the changes in teaching professionalism of beginning science-gifted education teachers through mentoring in the aspects of pedagogical content knowledge. We selected two beginning teachers whose teaching careers in science-gifted education were less than five years. The teachers planed, performed and reflected on science instructions for secondary science-gifted students through mentoring during nine class hours over three times respectively. We observed their instructions and analyzed the taped videos, the materials, the transcripts for in-depth interviews with mentees, and discussions between mentor and mentee, researcher's field notes by using the constant comparative method. This study revealed that the mentoring, although there were many limitations, positively changed the mentees' practical knowledge about the curriculum for science-gifted education, the instructional strategies for science-gifted education, the assessment in science-gifted education, the science-gifted students, and the science content. These results suggest that the mentoring will be useful in improving the teaching professionalism of beginning science-gifted education teachers and provide meaningful implications in finding the ways to use it effectively in science-gifted education.

An Analysis of Teaching Strategies of Science Teacher's Teaching in Science Museum (과학관 학습 실행에서 나타난 과학 교사의 교수 전략 분석)

  • Han, Moonjung;Yang, Chanho;Noh, Taehee
    • Journal of The Korean Association For Science Education
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    • v.34 no.6
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    • pp.559-569
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    • 2014
  • In this case study, we investigated teaching strategies of science teacher's teaching in science museum. Two secondary science teachers who completed a teacher training course on teaching in science museums participated in this study. We conducted interviews about their perceptions on teaching in science museum and their teaching plans before teaching. Then, we observed and recorded their teaching practices in the science museum throughout one semester, and collected all of the teaching materials. The interviews were also conducted after every lessons and at the end of the semester. For the analysis of teaching strategies, we used a framework that was revised from the framework for museum practice (FMP). The analysis of results revealed that the teachers understood the significance of planning the activities in a series of pre-visit, during-visit, and post-visit, so that they structured their teaching as continuous activities, not as an one-time event. However, they showed differences in the extent of connecting the activities with the national science curriculum according to their teaching objectives. In addition, there were differences in strategies such as promoting social interaction, evoking students' curiosity and interest, providing students with choices and control, and inducing engagement and challenge depending on each teacher's perceptions and experiences on teaching in science museum. These results suggest that science teacher education for the professional development of teaching in science museum should systematically provide knowledge and experiences on teaching strategies based on appropriate perceptions on teaching in science museum.

A study on the Need for Curriculum Contents in each Sub-area of High School Home Economics Education (고등학교 가정과 교육을 위한 교과과정 영역별 필요도)

  • 이금남;김행자;안영희;이남기
    • Journal of Korean Home Economics Education Association
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    • v.8 no.1
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    • pp.1-10
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    • 1996
  • This study aims at finding a new home economics education which will include male and female students as its teaching objects, and then providing home economics teachers with useful materials. For this purpose I examined analized male and female the upper secondary school students’and parents’recognition and demand to the home economics education The conclusion of this study is summarized as follows: 1. There was significant difference between male students(73.7%) and female students(89.8%) in the necessity for studying Home Economics(P<.001). In the necessity of Home Economics education, male students emphasized the spiritual part but female students emphasized the functional part. In part of parents, there was no significant difference between fathers(95.5%) and mothers(96.4%). 2. The necessity of each part in the contents of Home Economics 1) In the part of family, there was significant difference between male and female students in the true nature of family, the role and responsibility of family, and the laws relating to family(P<.001). There was significant difference between mothers and fathers in the true nature of family and the role and responsibility of family. Fathers and male students emphasized the true nature of family and the role and responsibility of family more than mothers and female students did. 2) In the Home management and economy parts, there was significant difference between male and female students in the significance of home management(P<.001), the relation of family to society(P<.001), and fluctuating measures for home economy. There was significant difference between fathers and mothers in the relation of family to society(P<.05). Fathers and male students emphasized the relation of family to society more than mothers and female students did. Mothers, male and female students emphasized the importance of the protection of consumers. 3) In the clothes part, male students emphasized the role of clothes, the disign and making of clothes(P<.001), the present situation of the resources of clothing and the distribution of clothes (P<.05) more than female students did. 4) In the part of food, there was significant difference between male and female students in the kinds and function of nutritive elements(P<.05). Parents and students emphasized the importance of selecting good food. 5) In the part of housing, male students emphasized home planning, and arrangements and facilities of house more than female students did. Female students emphasized the interior of the house(P<.05). Fathers emphasized the planning of a residential space and arrangements and facilities of a house(P<.05) more than mothers did. 6) In the parts of human development and upbringing, and upbringing, male students emphasized the significance of being parents, family planning and the population problem(P<.001), pregnancy and delivery(P<.01), and the chracteristic of juvenile development(P<.05) more than female students did. Parents and students emphasized the importance of prevention and countermeasures for diseases and the significance of being parents.

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Determination of HONO Concentration and Investigation on Its Formation Mechanism Using a Continuous Measurement System in Indoor Environment of an Apartment (아파트 실내 환경에서 실시간 측정시스템을 활용한 HONO 농도 측정 및 생성기작 연구)

  • Park, Seung-Shik;Hong, Jin-H.;Lee, Jai-H.;Kim, Young-J.;Cho, Sung-Y.;Kim, Seung-J.
    • Journal of Korean Society for Atmospheric Environment
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    • v.24 no.1
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    • pp.16-29
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    • 2008
  • Nitrous acid (HONO) can be produced by heterogenous reactions of nitrogen dioxide on surface materials and direct emission from combustion sources. However, a little is known of indoor HONO levels or the relationship between residential HONO, NO, and $NO_2$ concentrations in occupied houses. Therefore, we measured simultaneously NO, $NO_2$, and HONO concentrations in living room of an apartment using continuous analyzers to study the production of HONO (June $22{\sim}30$, 2006). The 4-min average concentrations of indoor NO, $NO_2$, and HONO were 4.3 (range: $0.4{\sim}214.3$), 10.3 ($2.0{\sim}87.3$), and 1.8 ppb ($0.3{\sim}7.7$), respectively. Peak levels of HONO up to 7.7 ppb and 24-hr averages as high as 1.7 ppb were measured. In agreement with previous studies, indoor HONO concentrations increased during operation of an unvented gas range. Examination of the observed kinetics suggests that the secondary production of indoor HONO, possibly as a result of heterogeneous reactions involving $NO_2$ and $H_2O$ is associated with $[NO_2]^2[H_2O]\;(r^2=0.88)$ rather than with $[NO][NO_2][H_2O]\;(r^2=0.75)$. Three combustion experiments at nighttime were also carried out to investigate the effects of vented combustion on the HONO, NO, and $NO_2$ concentrations. It was found to release HONO for $10{\sim}15$ minutes after NO and $NO_2$ source was turned off, and peak values were finally attained. Compared to unvented combustion, peak $NO_2$ and HONO concentrations were 3.2 and 2.0 times lower at weak vented combustion (air flow: $340\;m^3/hr$) and 4.9 and 2.4 times lower at strong vented combustion (air flow: $540\;m^3/hr$), respectively, emphasizing importance of operating ventilation hood fan during combustion to improve indoor air quality.

Analysis on the Curriculum of Chemical Engineering Field in Specialized Vocational High School (특성화고 화공계열의 교육과정에 대한 실태 분석)

  • Lee, Kyu-Nyo;Yi, Kwang bok;Kim, So Yeon;Han, Soo Kyong;Rhee, Young-Woo
    • 대한공업교육학회지
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    • v.40 no.2
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    • pp.72-91
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    • 2015
  • This study is aimed at researching and analyzing the actual conditions of the curriculum and career path of chemical engineering field in specialized high school, and seeking for a curriculum improvement plan for activation by means of identity establishment of chemical engineering field. This study surveyed the actual conditions of school (department) regarding chemical engineering, and analyzed an adequacy among the curriculum, department name and acquired license. The results are as follows. Firstly, In order to the chemical engineering field to maintain the identity of chemical engineering and accept the changes in the industrial site, it is desirable for the department name to use the name of applied science, such as Applied Chemical Industry, Nano Chemical Industry, Environmental Chemical Industry, Energy Chemical Industry, Convergence Materials Science and Chemical Engineering, Ceramic Chemical Engineering, Biomolecular and Chemical Engineering, and Food Bio-chemical Engineering, which are derived from chemical engineering, and the revision of curriculum should be included. Secondly, it is necessary to diversify relevant licenses by standard department of chemical engineering field, and clarify the purpose of human resources development and the image of talented, considering the future course of graduates and the demand of industry, for the purpose of improving school-leveled curriculum to raise the possibility of employment. Thirdly, in accordance with the changing paradigm that secondary vocational education is changed from 'just-to-know education (knowledge)' to 'can-do education (capability)', it is necessary to make the performance ability-centered curriculum in which 'chemical engineering industry - chemical engineering vocational education - chemical engineering qualification' are integrated.