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초기강도 향상 혼화재가 플라이애시 치환 콘크리트의 공학적 특성에 미치는 영향
이주선(Lee Ju-Sun),박천진(Park Chen-Jin),한민철(Han Min Cheol),한천구(Han Cheon-Goo) 대한건축학회 2009 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.29 No.1(구조계)
Engineering characteristics of FA substituted concrete were analyzed in this study using admixture of FC and RP for the purpose of improving initial strength of FA concrete. First in fresh concrete, slump and air capacity satisfied objective range in all mixes of the mix design. Setting time was significantly reduced in comparison to FA substituted concrete by using performance improvement admixture. The time reached the level of plain mix under low temperature condition. As a characteristic of hardened concrete, compressive strength was high in the initial age and age of 28 days when performance improvement admixture was used in comparison to FA mix. Especially at high temperature, strength was similar to the plain mix. Satisfactory improvement in strength was verified. In case of rate of change in length from drying shrinkage, use of performance improvement admixture showed no large difference from FA mix. Synthesizing the above results, use of performance improvement admixture composed of 30% FA, FC (15% of mix) and RP (5% of mix) is expected to bring satisfactory acceleration of setting and improvement of strength regardless of curing temperature.
복합 유기섬유 혼입율 변화에 따른 고성능 콘크리트의 폭렬방지
이주선(Lee Ju-Sun),배장춘(Pei Chang-Chun),지석원(Jee Suk-Won),한창평(Han Chang-Pyung),양성환(Yang Seong-Hwan),한천구(Han Cheon-Goo) 대한건축학회 2008 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.28 No.1(구조계)
This study analyzed fire-resistant stability of high performance concrete according to the change of hybrid organic fiber. Firstly, from the flowing characteristics of the fresh concrete, all mixing conditions satisfied target range, the fluidity due to the increase of fiber was lowered to 20%, air content generally had no variation as the hybrid organic fiber contents is increased. From the characteristic of hardened concrete, the compressive strength showed the different tendencies, respectively according to fiber contents, in case of mixing with PP 0.025%, it was appeared to be increased by about 6.5% than plain. From the fire-resistant characteristic, it was over 0.1% in case of using PP alone and over 0.075% in case of using NY alone. But, in case of PP+NY, if it was over 0.05(0.025+0.025)%, spalling was appeared to be prevented, the smallest mass loss rate was appeared and the residual compressive strength rate also was appeared to be most excellent. Synthetically, considering the characteristic of the fresh concrete the mechanical characteristic and further the economical efficiency, the case of PP 0.025%+NY0.025% mixing is judged as the most efficient spalling prevention engineering method of high performance concrete.
고로슬래그 미분말을 다량 치환한 콘크리트의 온도의존성 분석
이주선 ( Lee Ju Sun ),이재삼 ( Lee Jae Sam ),류금성 ( Ryu Gum Sung ),한민철 ( Han Min Cheol ),이장화 ( Lee Jang Hwa ),한천구 ( Han Cheon Goo ) 한국구조물진단유지관리공학회 2008 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.12 No.1
This study analysis the fundamental properties of temperature-dependence corresponding the change of curing temperature classified by the replacement ratio of BS, and the results are summarized as following. As the properties of flow, plain satisfied with the target slump, and as the replacement ratio of BS increased, the flow increased, but the air content slightly decreased. The time of set delayed as the replacement ratio of BS increased, but the curing temperature 35℃, even with 80% BS replaced concrete, the time of set was faster than 5℃, 20℃ plain, so the temperature-dependence was much greater. The compressive strength was decreased as the replacement ratio of BS increased, especially as the curing temperature higher, the compressive strength was higher. Also as the age increased, the plain developed more strength, therefore it show the temperature-dependence is much larger.
고온가열상황 변화에 따른 고성능 콘크리트의 역학적 특성
이주선 ( Lee Ju Sun ),장기현 ( Jang Ki Hyun ),이보형 ( Lee Bo Hyeong ),한창평 ( Han Chang Peng ),양성환 ( Yang Seong Hwan ),한천구 ( Han Cheon Goo ) 한국구조물진단유지관리공학회 2008 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.12 No.2
This research analyzed the Mechanical Properties of high Performance concrete by heating temperature, Elevated Temperature Duration and heating speed change through mix-in, and has shown the following results. Hardened concrete characteristics, age 28 days compression strength, 79.6 MPa, showed a high strength range close to 80 MPa level and age 28 days tension strength was 4.4 MPa. Also, The residual compression strengths by varied heating speed and heating temperature were 6.7℃/min 12hr., 13.4℃/min 2hr. and 6.7℃/min 2hr. at 20℃, and dramatically dropped at over 300℃. In summary, in case of concrete structure fire, structure safety drops dramatically and heat resistance deteriorates as heating delays, and therefore proper safety diagnosis evaluation and human protection and structure damage reduction measures will be necessary.
음주운전자 275명 혈액 중 마약류 및 남용약물의 분석
최혜영,이주선,최상길,김은미,김재균,김영운,임미애,정희선,Choi, Hye-Young,Lee, Ju-Seon,Choi, Sang-Kil,Kim, Eun-Mi,Kim, Jae-Kyun,Kim, Young-Woon,Lim, Mi-Ae,Chung, Hee-Sun 대한약학회 2008 약학회지 Vol.52 No.2
Even though driving under the influence of drug (DUID) is a worldwide problem, we, Korea has no regulation system yet except for alcohol, and there are little cases reported related to DUID. In order to investigate the type of abused drugs for drivers in Korea, we tried to analyze controlled and non-controlled drugs in alcohol-positive blood samples. 275 whole bloods, which were positive for alcohol on the roadside test, were collected from the police for two months ($Nov.{\sim}Dec.$ 2006). The analytical strategy was constituted of three steps: First, alcohol in blood samples were confirmed and quantified by gas chromatography. Second, controlled drugs were screened by $Evidence_{investigator}\;^{TM}$ (Randox, U.K.) as preliminary test. It was based on immunoassay by biochip array analyzer. Nine groups of drug abuse were screened: amphetamines, methamphetamines, cannabis, cocaine, opiates, barbiturates, methadone, benzodiazepines I (oxazepam) & II (lorazepam). Finally, confirmation of these drugs was performed by GC-MS. Blood samples were extracted by solid-phase extraction by $RapidTrace^{TM}$ (Zymark, U.S.A.). After trimethylsilyl (TMS) derivatization, eluates were analyzed to GC-MS. Total 49 drugs were investigated in this study including controlled drugs, antidepressants, 1st generation antihistamines, dextromethorphan, nalbuphine, ketamine, etc. For rapid detection, we developed the automated identification system. It was made up a new software, "DrugMan", modified Chemstation data analysis menu and newly developed macro modules. A series of peak selection, identification and reporting of the results were performed automatically by this system. Concentrations of alcohol in 275 blood samples were ranged from 0.011 to 0.249% (average, 0.119%). Among 149 blood samples, just six samples (4.0%) were showed positive results to the immunoassay: one methamphetamine and five benzodiazepines group I. By GC-MS confirmation, only benzodiazepines were detected and methamphetamine was not detected from immunoassay positive blood sample. Besides these drugs, 5 chlorpheniramines, dextromethorphan, diazepam, doxylamine, ibuprofen, lidocaine and topiramate were also detected in whole bloods by GC-MS. Conclusively, the frequency of drug abuse for Korean drivers was relatively low. There was none case which illegal drug was detected. However these results were limited to alcohol positive blood samples, so it is necessary to analyze more samples including alcohol negative blood.
김은미,이주선,최혜영,최화경,정희선,Kim, Eun-Mi,Lee, Ju-Seon,Choi, Hye-Young,Choi, Hwa-Kyung,Chung, Hee-Sun 대한약학회 2008 약학회지 Vol.52 No.6
A qualitative and quantitative analytical method was developed for detection of methamphetamine (MA) and its main metabolite amphetamine (AM) in oral fluid. Oral fluids of eleven drug abusers were provided by Police, specimens were collected by stimulation with a cotton swab treated with 20 mg of citric acid ($Salivette^{(R)}$; Sarstedt, USA). As the preliminary test, oral fluid samples were screened for amphetamines by Fluorescence Polarization Immunoassay (TDxFLx, Abbott Co.). Extraction for MA was performed using solid-phase extraction (SPE) by $RapidTrace^{TM}$ (Zymark, USA) with mixed mode cation exchange cartridge, CLEAN $SCREEN^{(R)}$ (130 mg/3 ml, UCT) after dilution with phosphate buffer. Samples were evaporated and derivatized by pentafluoropropionic acid anhydride (PFPA). Quantitation of MA and AM was performed by gas chromatography-mass spectrometry (GC-MS) using selective ion monitoring (SIM), the quantitation ions were m/z 204 (MA), 208 (MA-$D_5$), 190 (AM) and 194 (AM-$D_5$). The selectivity, linearity of calibration, limit of detection (LOD) and quantification (LOQ) within- and between day precision, accuracy and recoveries were examined as parts of the method validation. All oral fluid samples gave positive results to immunoassay for MA (cut-off level, 50 ng/ml as d-amphetamine). Concentrations of MA and AM by GC-MS in eleven samples were ranged 104.2${\sim}$4603.3 ng/ml and 32.4${\sim}$268.6 ng/ml, respectively. Extracted calibration curves of MA and AM were linear over the two concentration range of 1${\sim}$100 and 50${\sim}$1000 ng/ml with correlation coefficient of above 0.999. LOQ of MA and AM was 1 and 3 ng/ml, respectively. The intraand inter-day run precisions (CV) for MA and AM were less than 10%, and the accuracies (bias) for MA and AM were also less than 10% at the two different concentrations 5 and 100 ng/ml at low calibration range, 50 and 1000 ng/ml at high calibration range. The absolute recoveries of MA and AM at low and high calibration ranges were more than 82% and 75%, respectively. In this study the qualitative and quantitative analytical method of MA in oral fluid was established. Oral fluid testing may detect drug use in past hours because of its shorter detection window than urine, and be useful in post-accident situations. So oral fluids will be most useful for testing drug abuse in the driving under the influence of drug (DUID) as the alternative specimens of urine.