초속경 LMC의 시험시공을 위한 시방배합 및 현장배합 연구

윤경구,김성환,정원경,최성욱 강원대학교 부설 석재복합신소재 제품연구센터 2002 석재연 논문집 Vol.7 No.-

본 논문은 콘크리트 배합시 발생하는 과도한 기포 발생 문제점을 해결하기 위하여 최적의 소포제 종류 및 혼입률 범위를 산정하여 초속경 라텍스 개질 콘크리트 성능을 개선하는 것이다. 초속경 라텍스 개질 모르타르 실험은 4종류의 소포제 A, B, C, D와 혼입률 0, 1, 2, 3%을 주요 변수로 하여 실험을 수행하였으며, 초속경 라텍스 개질 모르타르 및 콘크리트의 특성을 분석하기 위하여 공기량 시험, 압축강도 및 휨강도 시험을 수행하였으며, 투수특성을 분석하기 위해서 염화이온 투과시험을 수행하였다. 초속경 라텍스 개질 모르타르의 공기량시험 결과 소포제 종류에 상관없이 소포제 혼입률 1%이상 첨가시 공기량은 50%이상 감소하였다. 또한, 소포제 첨가에 의한 기포발생량 감소에 의해서 압축강도의 증진을 이루었다. 초속경 라텍스 개질 콘크리트 실험은 모르타르 실험에서 우수한 특성을 나타낸 A, C 소포제로 선정하여 실험을 수행하였다. 초속경 라텍스 개질 콘크리트의 강도 특성에서는 A 소포제 혼입률 1%에서 압축강도 235 kgf/㎠, 휨강도는 조기 교통개방에 요구되는 휨강도 기준 45kgf/㎠를 초과하는 49kgf/㎠를 나타내었다. 초속경 라텍스 개질 콘크리트의 투수성을 분석하기 위한 염화이온투과시험에서 A 소포제는 각각 혼입률 1%, 2%에서 가장 우수한 투수저항성을 나타내어 재령 28일에서는 통과전하량이 100쿨롱 이하를 나타내어 불투수성을 나타내었다. The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid-setting cement) by choosing the best antifoam agent type and the optimized quantity for performance improved RSLMC. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as the basic for RSLMC with the main experimental variables such as antifiamer types (A, B, C, D), antifoamer contents (0, 1, 2, 3%), and latex contents (15%). A series of RSLMC experiments, also, were carried out with the similar main experimental variables but with the selected antifoamer types (A, C). Air content test and compressive, flexural tests were carried out to measure the improved properties of RSLMM and RSLMC. Chloride ion permeability test was carried out to estimate water permeability resistance. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing a antifoam agent by 1%. Two kinds and the optimized quantities of antifoam agent were selected for using in RSLMC. The results of RELMC were obtained at a latex content of 15% and an antifoam agent quantity of 1% with antifoamer A type. The compressive strength and flexural strength at 3 hours after RSLMC placement were 235 kgf/㎠ and 49kgf/㎠, respectively, which exceeded the flexural strength criterion of 45 kgf/㎠ in order to open the RSLMC placed to traffic. The rapid chloride permeability test was used to evaluate the permeability of RSLMC. The optimited quantity of antifoamer A and C type were 1% and 2% for the permeability test, respectively. The chloride permeability using A and C antifoamer at 28 days were below 100 coulombs, which was the permeability rating of negligible according to ASTM.

VES-LMC 덧씌우기를 이용한 콘크리트 포장 보수

정원경,김용곤,김기헌,윤경구 강원대학교 산업기술연구소 2005 産業技術硏究 Vol.25 No.B

Since in 1970, the length of concrete pavements(JCP, JRCP and CRCP) are growing rapidly at both of main highways and local roads. Many of them are deteriorated and old enough to be repaired or replaced. The pavement is more important than the other infrastructures and it is very difficult to go around or block the traffic during the rehabilitation. The very-early strength latex-modified concrete(VES-LMC)may offer the advantages of high-early-strength, higher flexural strength, higher bond strength, and improved durability. The VES-LMC could be used at a kind of fast track ofr early opening to the traffic after 3 hours of concrete placement. The installation of VES-LMC overlay at Jung-Boo highway was successfully done from April 28 to 29, 2005. The traffic was closed at 07:00 PM and opened to traffic at 08:30 AM. The compressive and flexural strength of VES-MC were more than 28MPa, 6.2MPa after 4 hours, respectively.

제2형 당뇨병 환자에서 Voglibose와 Acarbose의 비교임상연구

정인경,정재훈,민용기,이명식,이문규,김광원,정윤이,박중열,홍성관,이기업 대한당뇨병학회 2002 Diabetes and Metabolism Journal Vol.26 No.2

연구배경:아카보스와 보글리보스는 ­glucosidase inhibitors로써 비록 약리학적 작용이나 부작용에 있어서 두 약물간에 차이가 있다는 것은 잘 알려져 있으나 당뇨병 환자를 대상으로 아직 이에 대한 두 약물간에 직접적인 비교에 대해 연구된 바는 없었다. 이에 저자등은 국내 2형 당뇨병 환자에 대해 유효성과 부작용 발현에 대해 두 약제를 비교하고자 무작위법에 의한 위약 대조군의 이중 맹검법 연구를 시행하였다. 방법:시험 약제 투여 4주간의 관찰기를 설정하여 공복혈당의 변화가 30㎎/dL 이하이고, 식후 혈당이 200㎎/dL 이상인 환자로 기타 제외 기준에 해당하지 않은 환자 53명을 대상으로 하여 보글리보스 군(24명)과 아카보스 군(29명)으로 무작위로 나누었다. 치료기간은 총 8주로 하였으며, 4주간 간격으로 혈청학적 검사와 부작용을 분석하여 치료 효과가 부작용을 평가하였다. 결과:1)혈당 변화:보글리보스군은 식후 1시간 혈당이 치료 후 4주, 8주째 의미 있게 감소하였도, 아카보스군은 식후 1시간과 2시간 혈당이 치료 후 4주, 8주째 의미있게 감소하였다. 또한 관찰기 혈당에 대한 치료 4주째 감소량은 아카보스군에서 더 큰 경향을 보였으나, 치료 8주째에는 두 군 간의 강하정도에 의미있는 차이가 없었다(p=0.569). 2)인슐린 치의 변화:보글리스 군은 식후 1시간 인슐린 치가 치료 전에 비해 치료 4주, 8주째 감소하는 경향을 보였고, 공복 인슐린이나 식후 2시간 인슐린치는 치료전 후에 의미 있는 차이가 없었다. 아카보스군에서는 치료 전후로 공복 인슐린, 식후 1시간과 2시간 인슐린치에 의미 있는 차이를 보이지 않았다. 두약제 간에 치료 전과 치료 8주사이의 식후 2시간 인슐린의 감소량이 보글리보스 군에서 의미있게 높았다(p=0.040). 3)당화혈색소:보글리보스 군은 치료 전에 비해 치료후 당화혈색소가 감소하는 경향을 보였고, 아카보스군은 치료 전에 비해 의미있게 감소하였다. 당화혈색소 변화량은 두 군간에 의미 있는 차이는 없었다(p=0.412). 4)지질대사의 변화:중성지방, 콜레스테롤, 고밀도 진단백 콜레스테롤에 대해 두 군간에 의미 있는 차이는 없었다. 5)부작용:소화기계 부작용의 빈도는 치료 4주째 보글리보스 군에서 의미 있게 낮았으나(p=0.028), 치료 8주째 부작용의 빈도는 두 군간에 의미 있는 차이가 없었다(p=0.215). 결론:2형 당뇨병 환자에서 보글리보스와 아카보스의 두 약제의 임상적 유효성과 부작용발현에 대해 비교한 결과 치료 후 8 주 후 혈당강화효과는 두 약제간에 유사한 효과를 보였으나 보글리보스군에서 4주째의 초기 위장관 부작용이 적었다. Background : Acarbose and voglibose are alpha-glucosidase inhibitors. Although different pharmacological effects and adverse abdominal events associated with the two drugs have been reported, no study directly compared acarbose and voglibose in diabetes has been undertaken. To compare the pharmacological effects and gastrointestinal adverse events between two drugs, a randomized, placebo-controlled, double-bind study was performed in type 2 diabetes patients. Methods : The period of study was 12 weeks(observation period: 4 weeks; treatment period: 8 weeks). Fifty-three patients were randomized into two groups(the acarbose group: 24 patients; the voglibose group: 29 patients). The serum glucose, insulin, fructosamine, HbA_1c, cholesterol, triglyceride and the incidence of adverse events were measured. Results : 1) The reduction of glucose from before treatment to 4 weeks after treatment was significantly higher in the acarbose group, but the change before treatment and 8 weeks after treatment in the two groups was similar(p=0.569). 2) The insulin significantly decreased after voglibose treatment(p=0.040). 3) HbAa_1c level tended to decrease in voglibose group, and there was a significant decrease after acarbose treatment. However, the change in HbA_1c level before and after treatment was similar between the two groups(p=0.412). 4) The two drugs did not cause any other changes in the total, HDL-cholesterol and triglyceride. 5) The number of patients with gastrointestinal adverse events was significantly low 4 weeks after voglibose treatment (p=0.049), but the incidence in the two groups was similar after 8 weeks(p=0.215). Conclusions : Acarbose and voglibose significantly improved postprandial hyperglycemia in diabetes. The incidence of gastrointestinal adverse events was low 4 weeks after voglibose treatment(J Kor Diabetes 26:134~145, 2002).

장방형내 저온 단일 수평 원관 주위의 동결현상에 관한 실험적 연구

정현철,윤재원,장원택,전승배,이동석,김병철 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

An experimental study on water in a rectangular cavity with a horizontal cooling tube was carried out to investigate the flow character and thermal behavior in the system. Each experiment was performed with variation of initial temperature and cooling tube temperature. When the cooling tube temperature was -4℃, the supercooling phenomenon was observed regardless of the initial water temperature. And the case of cooling tube temperature was -6℃ with initial temperature was below 4℃, the supercooling phenomenon was also observedin the large region of the test section. When the cooling tube temperature was -10℃, the local region of supercooling phenomenon was observed during the freezing process. And the higher initial temperature was, the higher supercooling degree and the less difference of the ice thickness between upward and downward was observed. It is shown that by controllingthe supercooling phenomena and the cooling tube temperature, it would lead to an increase efficiency of ice making.

콘크리트 공극 분석을 위한 평면간격계수의 제안

정원경,최성용,김성환,윤경구 江原大學校 産業技術硏究所 2005 産業技術硏究 Vol.25 No.A

Air void systems in hardened concrete has an important influence on concrete durability such as freeze-thaw resistance, water permeability, surface scaling resistance. Linear traverse method and point count method described at ASTM are the routine analysis of the air void system that have been widely used to estimate the spacing factor in hardened concrete. Recently, many concretes often have a spacing factor higher than the generally accepted 200-250㎛ limit for the usual range of air contents. This study is proposed to estimate the plane spacing factor by calculation of simplicity. The plane spacing factor need two parameters that are air content and numbers of air voids in the hardened concrete. Those obtained from the standard air-void system analysis of the ASTM C 457. The equation is valid for all values of paste-to-air ratio because the estimation of paste content is unnecessary at the using ASTM C 457. The plane spacing factor yields a similar estimate of the standard spacing factor.

TNF-α 유전자형과 방광암과의 관계

정필두,김은정,엄민식,서정원,윤석중,김종석,이상철,김원재 충북대학교 의학연구소 2001 忠北醫大學術誌 Vol.11 No.2

연구목적: TNF-α는 일부 종양의 종양화 과정과 관련이 있는 것으로 알려져 있다. 본 연구는 TNF-α 발현에 영향을 미치는 TNF-α 촉진자 -308 부위의 유전적 다형성이 방광암과 관련이 있는지 유무를 알고자 시행하였다. 대상 및 방법: 유전자 분석을 위하여 환자 113명 및 대조군 109명으로부터 혈액을 채취하여 genomic DNA를 분리한 후 PCR-RFLP 및 direct DNA sequencing을 통하여 TNF-α유전자의 다형성을 조사하여 방광암의 발생, 병기 및 분화도와 비교 검토하였다. 결과: TNF-α 촉진자 -308 부위의 유전형은 대조군에서는 GG형이 83.5%(90례 및 GA형이 16.5%(19례)로 관찰되었으며 AA형은 없었다. 환자군에서는 GG 형이 85.4%(97례), GA형 및 AA형은 각각 13.1%(15례)및 0.8%(1례)에서 관찰되었다. 두 군 모두에서 GG형이 가장 많이 나타났으며 다음으로 GA형을 보이고 AA형은 1례의 방광암 환자에서만 관찰되었다. -308부위의 경우도 두 군 사이에 유전자형의 차이는 없었다(p=0.259) 분화도별 분포를 보면 grade I이 20례, grade II가 49례, grade Ⅲ은 34례였고 병기별로 표재성인 경우가 90례였으며 침윤성은 14례였다. 분화도가 나빠질수록 GA형이 증가하였다(p=0.04). 그러나 병기와 TNF-α promoter -308부위의 유전자형 사이에는 유의한 상관 관계가 없었다(p=0.123). 결론: 방광암 환자의 혈액에서 GA genotype이 관찰되는 경우, 분화도가 나쁠 가능성이 매우 높기 때문에 좀 더 적극적인 치료와 세밀한 추적관찰을 함으로써 방광암으로 인한 사망과 암의 진행을 예방할 수 있을 것으로 기대한다. Purpose : Tumor necrosis factor-alpha (TNF-α) is involved in tumorigenesis of several cancers as an endogenous tumor promoter. The purpose of this study was to investigate whether genetic polymorphism of TNF-α promoter region (-308) was associated with human bladder tumor. Materials and Methods: The DNA from 113 and 109 respective blood samples of bladder tumor Patients and control group was analyzed by PCR-based restriction fragment length polymorphism (RFLP) and direct DNA sequencing methods to characterize the genetic polymorphism of -308 promoter region of the TNF-α gene in bladder tumor patients. We compared the association of bladder tumor with genetic Polymorphism of TNF-α promoter region(-308) in relation to the stage, grade, recurrence and progressio. Results : Eighty-six percents(97/113) of bladder tumor patients and 83.5% (90/109) of control group showed genotype GG at -308 region of TNF-α. Difference in genetic variations of TNF-α promoter (-308) did not exist between bladder tumor patients and control group(p=0.259). Tumor grade was significantly related to the GA genotype (p=0.04). The higher is the grade in bladder tumor, the more frequent was the GA genotype. Tumor stage, recurrence and progression were not significantly associated with genetic polymorphism of TNF-α promoter region (-308). Conclusion: The GA genotype of TNF-a promoter region (-308) had a significant impact on TNF-α production and was related to higher grade tumor compared to GG genotype. TNF-α serum levels in bladder tumor patients were significantly higher than controls. These data suggested that TNF-α might involve the tumorigenesis of the bladder rather than treatment or prevention of bladder tumor.

라덱스 혼입률에 따른 철근콘크리트의 휨파괴 거동특성

정원경,김동호,이주형,임홍범,윤경구 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

Reinforced concrete(R/C) is commonly used to structures because they have many merits that compressive strength, economy and so on. However, reinforced concrete has a crack at the tensile section which is due to the relatively lower tensile strength than its compressive strength. Latex modified concrete(LMC) has higher tensile and flexural strength than the ordinary portland cement, due to the interconnections of hydrated cement and aggregates by a film of latex particles. The purpose of this study was to investigate the flexural behavior of reinforced concrete beam with latex modified concrete, having the main experimental variables such as concrete types(ordinary portland cement concrete, latex modified concrete), latex contents(0%, 15%), flexural steel ratios(0.012, 0.0235), and with/without shear reinforcement. The beam of LMC showed considerably higher initial cracking loads and ductility than that of OPC, but, similar to ultimate strength and deflection. This might be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic, and colloidal properties of the latexes resulting in reduced water evaporation. The beam with latex modified concrete could be adopted at field for controlling and reducing the tensile crack due to its higher tensile strength.

소포제를 이용한 초속경 LMC의 특성 개선연구

윤경구,김성환,정원경,권혁찬 강원대학교 부설 석재복합신소재 제품연구센터 2003 석재연 논문집 Vol.8 No.-

본 논문은 콘크리트 배합시 발생하는 과도한 기포 발생 문제점을 해결하기 위하여 최적의 소포제 종류 및 혼입률 범위를 산정하여 초속경 라텍스개질 콘크리트 성능을 개선하는 것이다. 초속경 라텍스개질 콘크리트 실험은 2종류의 소포제 A, C와 혼입률 0, 1, 2, 3%을 주요 변수로 하여 공기량 시험, 압축강도 및 휨강도 시험을 수행하였다. 또한, 내구성 평가를 위하여 염소이온 투과실험도 수행하였다. 초속경 라텍스 개질 콘크리트의 공기량시험 결과 소포제 종류에 상관없이 소포제 혼입률 1%이상 첨가시 공기량은 50%이상 감소하였다. 또한, 소포제 첨가에 의한 기포 발생량 감소에 의해서 압축강도의 증진을 이루었다. 초속경 라텍스개질 콘크리트 실험은 A, C 소포제로 선정하여 실험을 수행하였다. 초속경 라텍스개질 콘크리트의 강도 특성에서는 A 소포제 혼입률 1%에서 압축강도 235kgf/㎠ , 휨강도는 조기 교통개방에 요구되는 휨강도 기준 45kgf/㎠를 초과하는 49kgf/㎠를 나타내었다. The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid-setting cement) by choosing the best antifoam agent type and the optimized quantity for performance improved RSLMC. The main experimental variables such as antifiamer types(A, C), antifoamer contents(0, 1, 2, 3%), and latex contents(15%). Air content test and compressive, flexural tests were carried out to measure the improved properties of RSLMC. the rapid chloride permeability was carried out to estimate a durability of RSLMC. The results of RSLMC showed that the decrease of 50% air content was obtained by admixturing a antifoam agent by 1%. Two kinds and the optimized quantities of antifoam agent were selected for using in RSLMC. The results of RSLMC were obtained at a latex content of 15% and a antifoam agent quantity of 1% with antifoamer A type. The compressive strength and flexural strength at 3 hours after RSLMC placement were 235kgf/㎠ and 49kgf/㎠, respectively, which exceeded the flexural strength criterion of 45kgf/㎠ in order to open the RSLMC placed to traffic.

하악 제1대구치 이소맹출의 치험례

소정원,이광희,라지영,안소연,김윤희,반재혁 大韓小兒齒科學會 2010 大韓小兒齒科學會誌 Vol.37 No.1

Ectopic eruption is caused by an abnormal direction of eruptive path, most common in maxillary first molar, mandibular lateral incisor, and maxillary canine, and sometimes mandibular first molar. Ectopic eruption of first molar leads to abnormal root resorption of second deciduous molar, which, if left untreated, could cause premature loss of second deciduous molar; mesial tilting and rotation of first permanent molar; lack of space for eruption of second premolar; and occlusal problems. Therefore early treatment is advised when diagnosed as ectopic eruption. Treatment of ectopic eruption in the first permanent molar involves providing proper guidance for the direction of eruption using interproximal wedging and distal tipping methods while preserving second deciduous molar. This case report shows satisfactory results of the ectopic eruption of mandibular first molars in young patients who were treated with Humphrey appliance and Halterman appliance. 이소맹출은 치아가 비정상적인 위치로 맹출하는 경우를 말하며, 주로 상악 제1대구치, 하악 측절치, 상악 견치에서 발생하며 하악 제1대구치에서는 드물게 발생한다. 제1대구치의 이소맹출은 흔히 제2유구치의 비정상적인 치근흡수를 야기하며, 이를 방치하게 되면 제2유구치의 조기상실, 제1대구치의 근심경사 및 회전, 제2소구치의 맹출 공간 부족 및 교합문제 등을 야기하게 되므로 이소맹출로 진단될 경우 조기 치료가 추천된다. 이소맹출은 대개 통상적인 방사선검사를 통해 발견되나, 간혹 제2유구치의 치근흡수가 심할 경우 치수가 감염되어 동통을 야기하는 경우도 있다. 이소맹출의 치료는 제2유구치를 보존하면서 제1대구치의 맹출 방향을 바로 잡아 주는 것으로 크게 치간이개(interproximal wedging)와 원심경사이동(distal tipping)을 이용한 방법을 사용한다. 본 증례들은 하악 제1대구치의 이소맹출을 보이는 환아들로, Humphrey appliance와 Halterman appliance를 이용하여 양호한 치료 결과를 얻었기에 보고하는 바이다.

콘크리트 鋪裝의 初期計測을 통한 初期擧動 特性分析

정원경,김동호,권혁찬,윤경구 강원대학교 산업기술연구소 2003 産業技術硏究 Vol.23 No.A

The purpose of this paper is to analysis of initial behavior of concrete pavement with initial measurement strain gauge for concrete pavement at field, and to investigate the field test results for field applicability testing. The early-age behaviors of concrete pavement slabs were measured using the strain gauges. From the slab depths and positions, the outputs from each gauges were recorded at initial curing period The initial measurement of concrete pavement and check of crack at the joint were performed. the results could be summarized as follows. From the results of concrete strength, compressive strength and flexural strength were showed 271kgf/㎝', 43kgf/㎝' respectively. From the tests of early-age strain measurement, it was found that the strain varied at the maximum value of 150μ ε and early1 behavior of concrete slab was showed a tensile strain However. for long-term was showed a compressive strain due to dry-shrinkage.