• 한국해양공학회지
• /
• 제24권1호
• /
• pp.146-152
• /
• 2010

Recently, the applied frequency of composite materials was increased from the viewpoint of lightweight, high strength and low cost when a leisure boat and a fishing boatwere built. However, studies on the mechanical properties of composite material with ship are rare. Specially, a leisure boat and fishing boat with FRP had been built by hand lay-up method. However, the vacuum infusion method is rising recently for ship building. The manufactured these FRP plates were combined by using the adhesive. Therefore, in this study Cleavage peel strength, Shear strength and fatigue limit of adhesive bonds by tensileloading were estimated. From test results, the strengths of FRP specimens made by the vacuum infusion method are higher than that of the hand lay-up method.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
• /
• pp.300-303
• /
• 2004

In this study, the mixing contents of ceramic powder and of shrinkage-reducing agent (SRA) influencing on the strength properties of MMA-modified polymer paste were examined. Regardless of SRA content, the flexural. the compressive and the adhesive strengths of the MMA-modified polymer paste tended to increase as the mixing content of ceramic powder increased. On the other hand, those strengths of the polymer paste tended to decrease as the mixing content of SRA increased without regard to the paste content. Furthermore. the adhesive strength of MMA-modified polymer paste in a wet condition decreased about $30-40\%$ of that in an air-dry condition without regard to the mixing content of ceramic powder and SRA.

• Archives of Plastic Surgery
• /
• 제42권5호
• /
• pp.614-618
• /
• 2015

Background Hand strength deficit following digital replantation is usually attributed to the mechanical deficiency of the replanted digit. Zone 1 replantation, however, should not be associated with any mechanical deficit, as the joint and tendon are intact. We evaluate shortterm motor functions in patients who have undergone single-digit zone 1 replantation. Methods A single-institution retrospective review was performed for all patients who underwent zone 1 replantation. Hand and pinch strengths were evaluated using standard dynamometers. Each set of measurements was pooled according to follow-up periods (within 1 month, 1 to 2 months, 2 to 3 months, and after 3 months). The uninjured hand was used as reference for measurements. Results The review identified 53 patients who had undergone zone 1 replantation and presented for follow-up visits. Compared to the uninjured hand, dynamometer measurements revealed significantly less strength for the hand with replanted digit at one month. The relative mean grip, pulp, and key pinch strength were 31%, 46%, and 48% of the uninjured hand. These three strength measurements gradually increased, with relative strength measurements of 59%, 70%, and 78% for 4-month follow up. Conclusions Despite the lack of joint or tendon injury, strength of the injured hand was significantly lower than that of the uninjured hand during the 4 months following replantation. Improved rehabilitation strategies are needed to diminish the short-term negative impact that an isolated zone 1 replantation has on the overall hand strength.

• 대한기계학회논문집
• /
• 제17권6호
• /
• pp.1321-1329
• /
• 1993

본 연구에서는 이들보다 매우 간단한 IS법, 즉 초기 변형률법(ISM: initial strain method)에 의한 크리프 수명예측식을 고안하여, 현재 화력발전용 고압 로터강 에 사용되고 있는 1%Cr-Mo-V강과 발전소 효율향상을 위해 최근 국내최초로 개발된 12% Cr강에 대하여 도출하였고, 이 도출식이 앞에서 언급한 여러 파라메트에 의한 결과와 비교 평가하여 장시간 강도 및 수명예측식으로 사용될 수 있음을 입증하였다.

• 한국농공학회논문집
• /
• 제48권1호
• /
• pp.51-60
• /
• 2006

This study was conducted to investigate experimentally the drying shrinkage and the strength properties of redispersible SBR and PAE powder-modified mortars. Polymer-cement ratio, content of shrinkage-reducing agent and antifoamer content were manipulated as the experimental variables. The peculiarity of this study is to obtain a high early-age strength by using the portland cement and alumina cement with the ratio of 8 : 2. Until 7 days of age, the drying shrinkage remarkably increased up to $1\~2\times10^{-4}$, while it tended to decrease as the ratio of polymer to cement ratio and the content of shrinkage-reducing agent increased. Polymer-cement ratio was effective in improving the flexural, tensile and adhesive strengths: As the ratio increased, the strengths correspondingly increased. The flexural strength was in the range of $7\~11$ MPa, the tensile strength was $3.5\~5$ MPa and the adhesive strength was $1.2\~3.9$ MPa. On the other hand, the compressive strength tended to decrease as the polymer-cement ratio increased, and it was in the range of $23\~39$ MPa. All strengths, flexural, tensile, adhesive and compressive strengths, decreased as the content of powder shrinkage-reducing agent increased. It turned out that the polymer-cement ratio influenced more on the behavior of drying shrinkage and the properties of strength than the powder shrinkage-reducing agent did.

• 약학회지
• /
• 제58권1호
• /
• pp.40-46
• /
• 2014

Drugs with a narrow therapeutic index (NTI) require very precise dosing. Warfarin and digoxin are the examples of NTI-drugs and dosing of them varies widely for different patients. However, in South Korea, only two strengths of warfarin and one of digoxin are commercially available. This is a big barrier for the precise dispensing and has potential safety risks to patients, particularly to elderly patients. To find a potential solution to the problem, an analysis of the prescribed doses and dispensing patterns of those drugs was performed. Data were collected by computer-facilitated prescription review in a university hospital. The period screened was from May 1st, 2012 to April 30th, 2013. All the prescriptions with either warfarin or digoxin tablets were selected for this study and dispensing patterns were analyzed according to the prescribed doses. A total of 17,017 warfarin prescriptions were analyzed; 8,148 for inpatient prescriptions, 8,869 for outpatient prescriptions, respectively. Of the 23 kinds of prescribed doses, 2 mg (19.9%) was most frequent, followed by 3 mg (13.2%) and 2.5 mg (11.7%). By analyzing the dispensing patterns, 60.3% (10,253) of the prescriptions required pill splitting and 72.0% of them were for the patients 65 years old and over. On the other hand, 4,350 digoxin prescriptions were included in this study. Of the 6 kinds of prescribed doses, 0.125 mg (71.2%) was most frequent, followed by 0.0625 mg (20.2%). Among the prescriptions for digoxin, 92.0% (3,998) should be split and 65.7% of them were for the patients aged 65 years and over. Despite limitations of strengths, various doses of warfarin and digoxin were prescribed. Furthermore, more than half of the prescriptions that required pill splitting were for elderly patients. The results from this study suggest that different strengths of warfarin and digoxin should be provided for accuracy of dispensing and safety for patients receiving them.

• 한국강구조학회 논문집
• /
• 제16권1호통권68호
• /
• pp.33-42
• /
• 2004

SN 강재를 건축구조용으로 사용하기 위해서는 설계기준강도가 제정되어야 한다. 선행 연구로써, SN400B/490B 후판재로 재판한 SN400B/490B 원형강관과 SPAP235/325 및 SPAR295 각형강관의 물성을 평가하였다. SN400B/490B 후판재와 비교했을 때 STKN400B/490B 원형강관의 항복인장 및 인장강도는 상승하였지만, 제조 프로세스에 무관하게 STKN400B/490B 원형강관의 규격을 만족 하였다. 그러나 SPAP235/325 각형강관 모서리부에서의 항복인장 및 인장강도는 규격을 벗어났다. 이것은 SPAP235/325 각형강관 규격에서 정하고 있는 값이 모서리부에서의 값이 아니라 변에서의 값이기 때문이다. STKN490B 원형강관에 발생한 최대 인장잔류응력은 모재 항복강도 수준이며, 최대 압축잔류응력은 모재 항복강도의 40% 수준이었다. 또한 SPAP325 각형강관에 발생한 최대 인장잔류응력과 최대 압축잔류응력은 모두 모재 항복강도의 80% 수준이었다. 중심압축실험을 한 결과 STKN490B 원형강관의 좌굴강도는 제조 프로세스에 관계없이 별 차이를 보이지 않았다. 그러나 각형강관의 경우는 SPAP325 각형강관이 SN490B로 built-up한 각형강관보다 좌굴강도가 높게 나타났다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권2호
• /
• pp.1201-1216
• /
• 2017

In this study, we described the development of a methodology to measure tip-pinch strength on the paretic hand rehabilitation device and aimed to investigate reliability of the device. FSR sensors were embedded on the device, and tip pinch strength was estimated with data collected from the sensors using a developed equation while participants were demonstrating tip pinch. Reliability tests included inter-rater, test-retest, and inter-instrument reliability. B&L Engineering pinch gauge was utilized for the comparison. Thirty-seven healthy students participated in the experiment. Both inter-rater and test-retest reliability were excellent as Intraclass Correlation Coefficients (ICCs) were greater than 0.9 (p<0.01). There were no statistically significant differences in tip-pinch strengths. Inter-instrument reliability analysis confirmed good correlation between the two instruments (r = 0.88, p < 0.01). The findings of this study suggest that the two instruments are not interchangeable. However, the tip-pinch mechanism used in the paretic hand rehabilitation device is reliable that can be used to evaluate tip pinch strength in clinical environment and can provides a parameter that monitors changes in the hand functions.

• Journal of the Korean Wood Science and Technology
• /
• 제44권5호
• /
• pp.664-676
• /
• 2016

최근 여러 사회적인 변화에 따라 한옥에 대한 수요가 증가하고 있다. 하지만 한옥은 수가공으로 인한 가격 상승의 큰 문제점을 가지고 있다. 따라서 한옥 접합부의 모듈화를 위해 기계가공과 수가공과의 성능비교를 하였다. 더글라스퍼를 이용하여 두 가공법으로 실대재 주먹장을 제작하였다. 두 가공법에 대해 휨 성능을 평가하였다. 평균 최대하중은 같은 치수의 그룹을 비교했을 때 기계가공이 수가공에 비해 약 1.5배 더 높았다. 유의성 검증결과 두 가공법 모두 각 요소의 크기변화는 강도에 큰 영향을 미치는 것으로 나타났다. 다중회귀분석을 통해 목길이와 목두께는 최대하중과 비례 관계였으나 목너비는 반비례관계인 것을 알 수 있었다. 본 연구는 한옥 접합부를 모듈화 함에 있어 기초자료로 사용할 수 있을 것이다.

• 한국해양공학회지
• /
• 제27권4호
• /
• pp.45-54
• /
• 2013

In this study, various types of composite materials and adhesives that are actually used in the shipbuilding field for small ships, leisure boats, and fishing boats were applied in the hand lay-up method and vacuum infusion method to manufacture specimens. Then the tensile strength, tensile modulus, flexural strength, and flexural modulus values of these specimens were obtained. In addition, the barcol hardness and fiber content were obtained from the specimens. The results showed that the strengths of the specimens manufactured using the vacuum infusion method were higher than those manufactured using the hand lay-up method. Moreover, the barcol hardness and fiber content were also higher in those manufactured using the vacuum infusion method. The specimens manufactured using the vacuum infusion method were thinner despite their large fiber content.