하이브리드 섬유 보강 콘크리트의 휨인성 및 휨인장 강도에 관한 실험적 연구

趙勇範,朴弘用 明知大學校 産業技術硏究所 2009 産業技術硏究所論文集 Vol.28 No.-

Fiber reinforced concrete is increasing used in practice because of its excellent cracking resistance. There are various types of fiber such as steel fiber, glass fiber, synthetic fiber and organic fiber. Many trials to add more than two types of fiber to concrete mix have been being made to enhance ductility and maximum load bearing capacity as well as cracking resistance. Recently, a new type of polyolefin fiber having a good mechanical properties is developed, and it needs to examine a possibility for the new fiber to be used as a reinforcing fiber with other types of fiber or by itself. The objective of this study is to find out flexural toughness and tensile strength of concrete reinforced with steel and polyolefin fibers. Four point beam tests were performed with 324 specimens following two standard tests methods: KS F 2566 and ASTM 1399-02. From the test results, the effects of volume fraction of fibers, and aspect ratio of steel fiber on the toughness and tesile strength were found, and the optimal ratio of steel fiber to Dolvolefin fiber was suggested.

인조 합성 테니스 바닥재의 지면 반력 분석

조승제,정미라,서국웅,박승범,윤양진,이훈식,강영택 釜山大學校 附設 體育科學硏究所 1998 體育科學硏究所 論文集 Vol.14 No.-

Some authors suggest that certain types of surfaces are the origin of such injuries. A few years after the first medical concerns about surfaces were voiced, publications of biomechanical measurements apperared, describing accleration, force, and impact measurement on different types of surfaces. In many sport activities, surfaces can be under very high dynamic load. This was the reason for the development of various methods for impact simulation, like the development of various methods for impact simulation, like the artificial athlete. Furthermore, it is important to collect information about the hardness of new and already existing surfaces in sport arenas. The idea on which this measuring system is based Is as follows: The stiffness of the material can be computed from the kinematics measurd at touch down of a rigid body onto a material sample. The results show the following The result for the artifical surfaces(Synpave ace) is surprising. It is known that these surfaces are much harder than synpave rebound classic, synpave spring. This finding suggests that it may be possible that the subjective impression is used as one criterion in the selection of landing(or style) strategies. The number of subjects in this experiment is too small to make statistically significant conclusions. It is shown analytically that when an object a deformable surface, the acceleration it experiences is inversely propotional to its mass. In future, it need to stress that the interaction between shoe and surface is important, and this aspect has now become well accepted. Considering biomechanical aspect in player's injury, it request Korean Standards for synthetic playing surfaces in sport like ASTM(America Society for Testing & Materials) standards of America, DIN 18035 standards of Germany, BSI standards of U.K.

근위 대퇴정을 이용한 대퇴 전자부 골절의 치료

김범수,류석우,고상훈,조성도,양정훈,박문수 대한골절학회 2004 대한골절학회지 Vol.17 No.1

글래스비드 방법과 분말프레스 방법을 이용한 지르코니아 분말시편의 반정량 엑스선형광분석

강종봉,조범래,양성구 경남대학교 신소재연구소 1999 論文集 Vol.11 No.-

XRF는 시편의 종류에 따라 벌크, 분말 등 여러 가지 형태의 시료를 간단한 전처리 조작에 의해 빠른 시간에 분석할 수 있다는 장점으로 파인세라믹스의 원소분석으로 이용되고 있다. 그러나 시편들의 전처리 방법에 따라 분석의 결과가 달리 나타나고 있어, 본 실험험에서는 분말프페스형 시편과 글래스비드형 시편에서의 분석결과 차이를 밝히고자 하였으며, 분석결과에 미치는 영향들을 살펴보고자 하였다. 글래스비드형 시편인 경우 첨가하는 10배 이상의 플럭스 때문에 측정시편에 포함된 실제 분석하고자하는 시료의 양이 적어 오차의 범위가 크게 나타났다. 미량원소의 분석일 경우 글래스비드형 시편이 분말프레스형 시편의 시편보다 측정결과에서 많은 오차를 나타낸다. 이것은 X-선이 조사되는 영역에서 실제 시편내의 시료의 양이 미량 원소 분석의 오차를 나타냄을 알 수 있었다. XRF(X-ray Fluorescence Spectrometer) is one of the element analyzing instruments. which can be used to analyze ceramic materials of bulk, powder and various forms. The advantage of XRF is rapid analysis of elements in ceramics with simple sample preparation. In this study, the difference in results between pressed powder method and glass bead method were evaluated and the effects of sample preparation the final results were examined. The flux included in glass bead method, which is more than 10 times of samples, affected the final analyzing result. Trace element analysis in XRF could be affected by the sample amount because the region of X-ray beam is related the sample amount.

혈관내초음파로 평가한 스텐트를 삽입한관동맥의 형태학적 특징

정남식,홍범기,임세중,백성일,이문형,장양수,심원흠,조승연,김성순 대한순환기학회 1997 Korean Circulation Journal Vol.27 No.8

A Study of TCP Performance with Snoop Protocol over Fading Wireless Links

Cho, Yang-Bum,Cho, Sung-Joon The Korea Institute of Information and Commucation 2004 Journal of information and communication convergen Vol.2 No.4

In this paper, we have analyzed TCP performance over wireless correlated fading links with and without Snoop protocol. For a given value of the packet error rate, TCP performance without Snoop protocol is degraded as the fading is getting fast (i.e. the user moves fast). When Snoop protocol is introduced in the base station, TCP performance is enhanced in most wireless environments. Especially the performance enhancement derived from using Snoop protocol is large in fast fading channel. This is because packet errors become random and sporadic in fast fading channel and these random packet errors (mostly single packet errors) can be compensated efficiently by Snoop protocol's local packet retransmissions. But Snoop protocol can't give a large performance improvement in slow fading environments where long bursts of packet errors occur. Concerning to packet error rate, Snoop protocol results in the highest performance enhancement in the channel with mid-high values of packet error rate. This means Snoop protocol cannot fully fulfill its ability under too low or too high packet error rate environments.

Pulmonary Toxicity and Recovery from Inhalation of Manual Metal Arc Stainless Steel Welding Fumes in Rats

Yang, Mi-Jin,Kim, Jin-Sung,Yang, Young-Su,Cho, Jae-Woo,Choi, Seong-Bong,Chung, Yong-Hyun,Kim, Yong-Bum,Cho, Kyu-Hyuk,Lim, Chae-Woong,Kim, Choong-Yong,Song, Chang-Woo Korean Society of ToxicologyKorea Environmental Mu 2008 Toxicological Research Vol.25 No.3

The objectives of this study were to examine the lung injury and inflammation caused by manual metal arc stainless steel(MMA-SS) welding fume inhalation and to evaluate the recovery process. Sprague-Dawley rats were exposed to MMA-SS welding fumes for 2 h per day in a whole-body exposure chamber, with a total suspended particulate(TSP) concentration of $51.4{\pm}2.8mg/m^3$(low dose) or $84.6{\pm}2.9mg/m^3$(high dose) for 30 days. The animals were sacrificed after 30 days of exposure as well as after a 30-day recovery period. To assess the inflammatory or injury responses, cellular and biochemical parameters as well as cytokines were assayed in the bronchoalveolar lavage fluid(BALF). MMA-SS welding fume exposure led to a significant elevation in the number of alveolar macrophages(AM) and polymorphonuclear cells(PMN). Additionary, the values of $\beta$-n-acetyl glucosaminidase($\beta$-NAG) and lactate dehydrogenase(LDH) in the BALF were increased in the exposed group when compared to controls. After 30 days of recovery from exposure, a significant reduction in inflammatory parameters of BALF was observed between the exposed and recovered groups. Slight, but significant elevations were noted in the number of AM and PMN in the recovered groups, and AM that had been ingested fume particles still remain in the lungs. In conclusion, these results indicated that welding fumes induced inflammatory responses and cytotoxicity in the lungs of exposed rats. Fume particles were not fully cleared from lungs even after a 30-day recovery period.

A Phase 1 Study Using Autologous Natural Killer Cells in Patients with HAIC-Hepatocellular Carcinoma

( Sung Bum Cho ),( Chung Hwan Jun ),( Sung Kyu Choi ),( Woo Kyun Bae ),( Je Jung Lee ),( Yang Jun Kang ),( Cheol Kyun Cho ),( Yang Seok Ko ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: Natural killer (NK) cell-based immunotherapy has recently been tried with advances of understanding the role of immune defense against hepatocellular carcinoma (HCC). To improve NK cells therapy, we focused to increasing delivery of NK cells and synergic effect combined with hepatic arterial infusion chemotherapy (HAIC). Methods: We did a prospective, open label, phase 1 trial of the safety and efficacy of autologous NK cells through hepatic arterial infusion as sequential therapy after HAIC in advanced HCC patients. Between March 2016 and July 2017, 11 patients were included who showed favorable response more than stable disease (SD) after 2 sessions of HAIC in advanced HCC patients with child A. A total 4 sessions of HAIC were performed the protocols of infusion of cisplatin (25/m2) and 5-fluorouracil (750/m²) for 4 days every 3-4 weeks interval. The peripheral blood mononuclear cells of patients by leukapheresis were ob-tained after 3^rd HAIC and NK cells were expanded for 2 weeks under Current Good Manufacturing Practices (cGMP). Patients received planned dosage of NK cells through chemoport into hepatic artery for 5 days after 4^th HAIC (3 patients; 2.5x108, 3 patients; 5x10⁸, 5 patients; injection of 10x10⁸ NK cells). The primary end point was safety of NK cell injection; secondary endpoint included objective response rate (modified Response Evaluation Criteria In Solid Tumors), time to progression, dura-tion of response and immunologic efficacy. Results: Any adverse events of NK cells injection were none according to dosage. An objective response was observed in 7 patients (63.6%) included three complete responses and four partial responses. Stable disease was observed in 2 patients and progressive disease was in 2 patients and thus disease control rate was 81.8%. The mean duration of time to progression was 9.7±5.3 month and duration of response without chemotherapy was 6.1±5.2 month. The newly metastatic lesion was occurred in 3 patents (27.2%; lymph node 1 patients, Lung 2 patients). Two patients were died by tumor progression and others were still alive. The increasing immunologic response was observed in 5 patients (55 %) to evaluate cytotoxicity and NK cell proportion of peripheral mononuclear cells after NK cell injection. Conclusions: The HAIC and NK cells immunotherapy is safe and effective treatment in the advance HCC patient with favorable liver function. The additional studies are urgently required to establish the new novel treatment.

Pulmonary Toxicity and Recovery from Inhalation of Manual Metal Arc Stainless Steel Welding Fumes in Rats

Mi-Jin Yang,Jin-Sung Kim,Young-Su Yang,Jae-Woo Cho,Seong-Bong Choi,Yong-Hyun Chung,Yong-Bum Kim,Kyu-Hyuk Cho,Chae-Woong Lim,Choong-Yong Kim,Chang-Woo Song 한국독성학회 2008 Toxicological Research Vol.24 No.2

The objectives of this study were to examine the lung injury and inflammation caused by manual metal arc stainless steel (MMA-SS) welding fume inhalation and to evaluate the recovery process. Sprague-Dawley rats were exposed to MMA-SS welding fumes for 2 h per day in a whole-body exposure chamber, with a total suspended particulate (TSP) concentration of 51.4 ± 2.8 ㎎/㎥ (low dose) or 84.6 ± 2.9 ㎎/㎥ (high dose) for 30 days. The animals were sacrificed after 30 days of exposure as well as after a 30-day recovery period. To assess the inflammatory or injury responses, cellular and biochemical parameters as well as cytokines were assayed in the bronchoalveolar lavage fluid (BALF). MMA-SS welding fume exposure led to a significant elevation in the number of alveolar macrophages (AM) and polymorphonuclear cells (PMN). Additionary, the values of β-nacetyl glucosaminidase (β-NAG) and lactate dehydrogenase (LDH) in the BALF were increased in the exposed group when compared to controls. After 30 days of recovery from exposure, a significant reduction in inflammatory parameters of BALF was observed between the exposed and recovered groups. Slight, but significant elevations were noted in the number of AM and PMN in the recovered groups, and AM that had been ingested fume particles still remain in the lungs. In conclusion, these results indicated that welding fumes induced inflammatory responses and cytotoxicity in the lungs of exposed rats. Fume particles were not fully cleared from lungs even after a 30-day recovery period.

A New Six-rowed and Covered Barley(Hordeum vulgare L.) Cultivar, “Hyegang” with BaYMV Resistant, High Yield and Good Malt Quality

Yang-Kil Kim,Mi-Ja Lee,Jong-Nae Hyun,Seong-Bum Baek,Jong-Chul Park,Jai-Hyun Jeung,Hong-Jib Choi,Su-Hyun Cho,Mi-Jung Kim,Hyoung-Ho Park,Jae-Seong Choi,Tae-Su Kim,Kee-Jong, kim,Ki-Hun Park 한국육종학회 2012 한국육종학회 심포지엄 Vol.2012 No.07

Improvement of winter hardiness, diseases resistance and good quality have been recently received more attention by covered barley(Hordeum vulgare L.) breeders than ever in Korea. “Hyegang”, a new covered barley cultivar with similar maturing and high yield was developed by the National Institute of Crop Science, RDA in 2011. It was derived from the cross between “Milyang87/NWX-GB-G 2” and “Milyang87/Chalbori” with good quality. The initial cross was done in 2000 and the selected line, “Iksan445” (YB4625-B-B-6-2), showed high yield and good quality characteristics under yield trial test in 2008. It was cultivated three times for three years (2009~2011) in the four locations of regional yield trial (RYT) in korea and was investigated about agronomic and quality characteristics and released as “Hyegang”. The heading date was May 4 in upland and April 26 in paddy field which was 1 and 0 day lateness respectively than that of check cultivar, “Olbori”. The culm length was 77 cm which was 6 cm shorter than that with check cultivar. It showed the spike length of 4.7 cm, 800 spikes / m2, 64 grains / spike and 25.1g for 1,000 grains weight. It showed similar maturing and stronger resistance to barley yellow mosaic virus (BaYMV) compare to check cultivar. It showed higher diastatic power 216DP than that of check cultivar, ‘Olbori’. Average yield of “Hyegang” in the RYT was 4.61 MT/ha in upland and 4.38 MT/ha in paddy field, espectively.