• Computers and Concrete
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• 제19권5호
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• pp.443-449
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• 2017

Taking high geothermal tunnels as background, the deformation of concrete for shotcrete use was studied by simulating hot-humid and hot-dry environments in a laboratory. The research is made up by two parts, one is the influence of two kinds of high geothermal environments on the deformation of shotcrete, and the other is the shrinkage inhibited effect of fiber materials (steel fibers, polypropylene fibers, and the mixture of both) on the concrete in hot-dry environments. The research results show that: (1) in hot and humid environments, wet expansion and thermal expansion happened on concrete, but the deformation is smooth throughout the whole curing age. (2) In hot and dry environments, the concrete suffers from shrinkage. The deformation obeys linear relationship with the natural logarithm of curing age in the first 28 days, and it becomes stable after the $28^{th}$ day. (3) The shrinkage of concrete in a hot and dry environment can be inhibited by adding fiber materials especially steel fibers, and it also obeys linear relationship with the natural logarithm of curing age before it becomes stable. However, compared with no-fiber condition, it takes 14 days, half of 28 days, to make the shrinkage become stable, and the shrinkage ratio of concrete at 180-day age decreases by 63.2% as well. (4) According to submicroscopic and microscopic analysis, there is great bond strength at the interface between steel fiber and concrete. The fiber meshes are formed in concrete by disorderly distributed fibers, which not only can effectively restrain the shrinkage, but also prevent the micro and macro cracks from extending.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.25-28
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• 2007

In this study we measured the changes according to time respectively on the basis of 0, 30, 60 and 90 minutes, taking into consideration the decline in fluidity of concrete according to elapsed time to analyze manufacturing capability of batcher plant according to elapsed time of ready-mixed concrete manufactured in batcher plant, and offer basic data for mixture design of ultra-high strength concrete. The proportion of water-binder was 23.55, water content was 160kg/m3, proportion of replacement of crushed sand was 0, 20 and 40% at 3 level, and we applied to the same condition of triaxial component using blast furnace slag powder and silica fume as admixture. And to meet the demand of certain fluidity, we measured respectively on property before and after hardening of ultra-high strength concrete using superplasticizer. As a result of experiment, before hardening of ultra-high strength concrete showed the best fluidity in conditions of crushed sand replacement rates of 20% and superplasticizer composition of 1.95%, but it appeared that fluidity drops as time goes by in the same composition condition. And it appeared that when it comes to hardened, the changes of compression strength according to elapsed time by crushed sand replacement rates were within 1MPa. Therefore, it turned out that the difference of strength according to elapsed time was low and compression strength of 280dys in composition mentioned above appeared highly as 88MPa.

• 한국재료학회지
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• 제27권1호
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• pp.43-47
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• 2017

E (Electric) -glass fibers are the most widely used glass fibers, taking up 90 % of the long glass fiber market. However, very few papers have appeared on the physical characteristics of E-glass fibers and how they depend on the fiberizing temperature of fiber spinning. Glass fiber was fabricated via continuous spinning process using bulk E-glass. In order to fabricate the E-glass specimen, raw materials were put into a Pt crucible and melted at $1550^{\circ}C$ for 2hrs; mixture was then annealed at $621{\pm}10^{\circ}C$ for 2hrs. The transmittance and adaptable temperature for spinning of the bulk marble glass were characterized using a UV-visible spectrometer and a viscometer. Continuous spinning was carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of $1175{\sim}1250^{\circ}C$, while the winder speed was fixed at 500 rpm. Subsequently we investigated the physical properties of the E-glass fiber. The average diameter of the synthesized glass fiber was measured by optical microscope. The mechanical properties of the fiber were confirmed using a UTM (universal materials testing machine); the maximum tensile strength was measured and found to be $1843{\pm}449MPa$ at $1225^{\circ}C$.

• 비교문화연구
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• 제25권
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• pp.363-389
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• 2011

Modern Chinese Literature, the so-called 'feminist' is a very modern and the traditional criticism and took an important position in the double action. Because a woman's freedom from the bondage of traditional ethics of restoring the social status equal to men but to women does not give, that compared to men and women just the dimension of the problem of isolation is not just. It is dominated by yugajeok worldview by streamlining the whole Chinese society to build a modern society and the country was a critical task. However, multi-cultural life of Lin, Hui-yin and Ling, Shu-hua in the history of the world's attention to the shrine was worried attention to soils, rather than East-West dualism law by taking a mixture of both women in modern Chinese literature and Western literature from the center of efforts to overcome the traditional point hayeotdaneun feminist literature that may be different. Lin, Hui-yin and Ling, Shu-hua to overcome the Western-oriented culture really the true dream of China's globalization and localization could be regarded. She naesewotdeon the banner of feminist literature in the traditional 'anti feudal', 'free personality' silcheondoen under such slogans as well as women's liberation from traditional, male-oriented perspective away from the women's unique experiences and new understanding of the value of the superiority the concept of a woman, and was to create. In particular, the femininity of these women who traditionally associated with women and the unique culture - the creation of a new consciousness, a re-evaluation of traditional feminine skills and talents was to try to.

• 대한금속재료학회지
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• 제46권3호
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• pp.182-188
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• 2008

Carbon nanotubes(CNTs) have outstanding mechanical, thermal, and electrical properties. Thus, by placing nanotubes into appropriate matrix, it is postulated that the resulting composites will have enhanced properties. Cold spray can produce thick metal-based composite coatings with very high density, low oxygen content, and phase purity, which leads to excellent physical properties. In this study, we applied cold spray coating process for the consolidation of Cu/CNT composite powder. The precursor powder mixture, in which CNTs were filled into copper particles, was prepared to improve the distribution of the CNT in copper matrix. Pure copper coating was also conducted by cold spraying as a reference. Annealing heat treatment was applied to the coating to examine its effect on the properties of the composite coating. The hardness of Cu/CNT composite coating represented similar value to that of pure copper coating. It was importantly found that the electrical conductivity of the Cu/CNT composite coating significantly increased from 53% for the standard condition to almost 55% in the optimized condition, taking annealed ($500^{\circ}C/1hr$.) copper coating as a reference (100%). The thermal conductivity of Cu/CNT composite coating layer was higher than that of pure Cu coating. It was also found that the electrical and thermal conductivities of Cu/CNT composite could be improved through annealing heat treatment. The microstructural evolution of Cu/CNT coating was also investigated and related to the macroscopic properties.

• 대한본초학회지
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• 제34권1호
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• pp.13-21
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• 2019

Objectives : This clinical trial is performed to investigate the effect of improving the hypersensitivity reaction and the safety of powdered ethanol extract Codonopsis lanceolata (S. et Z.) Trautv. for allergic patients. Methods : This study was randomized, double blinded, placebo-controlled clinical trial. 60 allergic rhinitis subjects were randomly assigned to Treatment group(n=30) and Control group(n=30). They were received the test substance or placebo in their $1^{st}$ and $2^{nd}$ visit, and took it once a day, 1 powder bag per 1 time, for 8 weeks. The freeze dried powder of Codonopsis lanceolata (S. et Z.) Trautv. was mixed with 30% ethanol and the filtrate was collected thrice with constant stirring of the mixture. The placebo was prepared in the same form as the test substance by replacing with corn starch. Total Nasal Symptom Score(TNSS) questionnaires and laboratory tests were performed at the screening and last visit to evaluate the efficacy. And to assess safety, vital signs and adverse events were confirmed at every visit. Statistical analysis about the result was performed using SAS 9.4. Results : In treatment group, there was a significant decrease in B cell after taking the test substance(p<0.005). And there was a statistically significant difference between groups(p<0.005). Changes in nasal symptoms were not statistically significant between groups, and both groups showed statistically significant differences before and after the test(p<0.0001). Also there were no adverse events associated with the clinical trial product. Conclusions : This clinical trial showed that Codonopsis lanceolata (S. et Z.) Trautv. extract was helpful in improving the hypersensitivity reaction in allergic patients without significant side effects.

• 한국구조물진단유지관리공학회 논문집
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• 제17권3호
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• pp.136-144
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• 2013

본 연구에서는 각종 산업부산물 및 도시형 리싸이클링 재료 등의 재생자원을 안전하게 유효 이용할 수 있는 방안으로 BFS 및 SS를 활용한 저강도 콘크리트의 기초적 물성을 파악하기 위하여 플로우 및 블리딩, 일축압축강도, 환경오염평가를 중심으로 실험을 실시하였다. BFS 및 SS를 활용한 저강도 콘크리트의 경우 최소단위수량의 확보를 통한 유동성 개선 및 블리딩율 억제 또한, 현장 적용성을 고려한 일축압축강도의 확보에 있어 사용 잔골재의 차이에 상관없이 BFS 6000 이상을 30% 범위에서 혼입하는 것이 가장 유효한 것으로 나타났다. 특히, SS의 유효 활용 측면에서 BFS 8000을 30% 범위에서 혼합하여 사용하면 유동성 개선 및 블리딩율 억제, 일축압축강도의 확보는 물론 현장 적용에 있어 가장 최적의 배합조건으로 나타났다. 한편, SS를 활용한 시멘트 개량토를 대상으로 유해물질 함유량 및 용출시험을 실시한 결과 모두 환경 기준치 이하를 만족하는 것으로 나타나 주변 환경에 미치는 영향은 없는 것으로 확인되었다.

• 한국산학기술학회논문지
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• 제17권6호
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• pp.98-105
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• 2016

집단사회성놀이는 놀이를 통한 사회성 증진을 목적으로, 그룹활동을 통하여 일상생활에서 필요로 하는 목적 있는 활동, 인지, 신체움직임 등 여러 요소들을 잘 조합하여 자유롭게 자아를 표현시키는 치료적 방법이다. 이를 타인과의 의사소통 능력이 저하된 자폐청소년들에게 적용하여 궁극적으로 자폐청소년들의 대인관계 개선과 사회성을 증진을 유도함으로써 그 효과를 검증하고자 본 연구를 실시하였다. 본 연구는 대전 소재 주간보호센터를 이용하는 사회성에 결함을 가지고 있는 8명의 자폐청소년을 대상으로 단일군 전후실험설계를 적용하였다. 집단사회성놀이 프로그램은 2013년 10월부터 12월까지 주 2회씩 7주간(총 14회기), 한 회기 당 60분씩 시행하였고 중재 전후의 사회성을 Wilcoxon 순위검정을 실시하여 비교분석 하였다. 연구결과 이화-자폐 아동 행동 발달 평가(E-CLAC)와 사회성숙도 검사의 점수의 총점이 $39.88{\pm}6.78$에서 $47.00{\pm}4.28$, $49.96{\pm}28.00$에서 $61.36{\pm}21.75$로 각각 통계적으로 유의한 변화가 있었음을 확인할 수 있었다. 세부적으로는 집단에서의 적응, 지시 따르기, 행동 빈도 증진 등의 하위항목에서 유의한 변화가 크게 나타났다. 결론적으로 집단사회성놀이에 포함된 집단활동 요소와 대상자들의 발달을 고려한 놀이 활동 요소가 복합적으로 작용하여 자폐청소년의 사회성 증진 효과에 효과적으로 나타났음을 확인할 수 있었다.

• 청정기술
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• 제13권4호
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• pp.300-307
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• 2007

본 연구에서는 연료분출각의 변화에 따라 보염기(cylindrical stabilizer) 후류에 형성되는 확산화염의 화염 안정성, 재순환영역의 길이 및 온도, 보염기 후류의 난류강도 분포, 재순환영역의 연소가스 농도 등을 측정하고, 화염의 직접사진 및 슐리렌사진을 촬영하여 확산화염의 연소특성을 고찰하였다. 화염안정성은 연료분출각과 주류공기 유속의 영향을 받으며, 재순환영역의 길이와 온도는 연료분출각의 영향을 받았다. 재순환영역의 길이가 짧고 온도가 낮을수록 화염안정성이 양호하지만, 연료분출각의 변화에 따른 난류강도 분포에는 별로 차이가 없었다. 재순환영역 내 미연가스 농도가 높고 이산화탄소 농도가 낮은 경우, 화염안정성은 양호하지만 연소상태는 불량한 것으로 나타났다. 연소효율, 고부하 출력, 대기환경, 연료의 청정연소조건 등을 고려하여 적절한 연료분출각을 선정함으로써 양호한 연소조건을 유지할 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권5호
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• pp.601-605
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• 2005

Three lines of White Leghorn (WL) chickens (IWJ, IWG and IWC) maintained at Central Avian Research Institute, Izatnagar (UP), were used for chorioallantoic membrane (CAM) and liver tumour (LT) assay. Eleven-day-old embryos of each line were partitioned into three groups and inoculated with 0.2 ml of subgroup A, subgroup C and an equal mixture of subgroup A and C Rous sarcoma virus (RSV). Subgroup virus receptor on the cell surface membrane for subgroup A is coded for by tumour virus a (tva) locus and for subgroup C by tumour virus c (tvc) locus. The random association of the genes at the tva and tvc loci in IWJ and IWC line was assessed and the $x^2$-values for phenotypic classes were found to be significant, indicating the linkage between the tva and tvc loci. The linkage value was estimated to be 0.09 on pooled sex and pooled line basis. On the basis of four subclass tumour phenotypes a 4-allele model was proposed for tva locus having $a^{s1}$, $a^{s2}$, $a^{r1}$ and $a^{r2}$ alleles and the frequencies were calculated as 0.47, 0.13, 0.13 and 0.27 for IWJ line, 0.31, 0.33, 0.14 and 0.22 for IWG line and 0.44, 0.11, 0.21 and 0.24 for IWC line, respectively. Similarly, for tvc locus the frequencies of four alleles i.e. $c^{s1}$, $c^{s2}$, $c^{r1}$ and $c^{r2}$ were calculated as 0.42, 0.20, 0.21 and 0.17 for IWJ line, 0.42, 0.17, 0.27 and 0.14 for IWG line and 0.30, 0.21, 0.16 and 0.33 for IWC line, respectively. The $x^2$-values for all classes of observations were not significant (p>0.05), indicating a good fit to the 4-allele model for the occurrence of 4-subclass tumour phenotypes for tva and tvc loci. On the basis of the 2-allele model both tva and tvc locus carries three genotypes each. But, on the basis of the 4-allele model tva and tvc locus carries 10 genotypes each. The interaction between A-resistance and C-resistance (both CAM and LT death) was ascertained by taking the 10 genotypes of tva locus and 3 genotypes of tvc locus by pooling the lines and partitioning the observations into 3 classes. The $x^2$-values for the genotypic classes of CAM (-) LT (+) and CAM (-) LT (-) phenotypes to mixed virus (A+C) infection were found to be highly significant (p<0.01), indicating increased resistance, which indicates the joint segregation of $a^r$ and $c^r$ genes, suggesting the existence of close linkage between the tva and tvc loci. Therefore, an indirect selection approach using subgroup C viruses can be employed to generate stocks resistant to subgroup A LLV, obviating contamination with the most common agent causing LL in field condition.