• The Korean Journal of Rheology
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• v.10 no.3
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• pp.173-183
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• 1998

본 연구에서는 Advanced Rheometric Expansion System(ARES)를 사용하여 대진폭 진동 전단 변형하에서 발생하는 폴리이소부틸렌(PIB) 농후 용액의 비선형 점탄성 거동을 저 장탄성율과 동적점도의 변형량 의존성 및 응력파형의 fast Fourier transform(FFT) 해석을 통해 고찰하였다. 스트레인 진촉을 단계적으로 증가시키면서 측정한 동적 점탄성으로 부터 저장탄성율 및 동적점도의 선형응답한계를 결정하고 이들에 미치는 각주파수의 영향을 조사 하였다. 그리고 응력파형의 Fourier 전개로부터 유도되는 비선형 점탄성함수를 사용하여 비 선형 거동을 설명하였다. 끝으로 비선형 점탄성 거동의 정도를 나타내는 비선형 거동 지수 를 정의하고 이들에 미치는 각주파수의 영향에 대해 검토하였다. 이상의 연구를 통해 얻어 진 결과를 요약하면 다음과 같다.(1) 선형 응답한계는 고분자 용액의 특성시간의 역수보다 높은 각주파수 범위에서는 일정한 값을 유지하지만 특성시간의 역수보다 낮은 각주파수 영 역에서는 각주파수가 감소할수록 증가한다. (2)선형응답한계 이상의 대변형하에서는 3차비선 형 점탄성 함수 이상의 고차항의 영향이 크게 작용하며 이로인해 비선형 거동이 발생된다. (3) 스트레인 진폭을 단계적으로 증가시키면서 측정한 저장탄성율 및 동적점도의 변형량 의 존성은 응력파형의 Fourier transform으로부터 유도된 1차 비선형 점탄성 함수의 변형량 의 존성을 나타낸다 (4) 저장탄성율 및 동적점도의 변형량 의존성으로부터 유도된 비선형 거동 지수는 탄성적 서질과 점성적 성질에 대한 비선형 특성을 평가하기 위한 유요한 방법으로 인정된다. (5) 비선형 점탄성 거동의 정도를 나탄는 비선형 거동지수는 특정한 각주파수에서 최대치를 가지며 또한 탄성적 거동이 점성적 거동에 비해 더욱 큰 각주파수 의존성을 나타낸다.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.243-255
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• 2016

The developed composite index has limits to estimate and predict economic status due to economic pattern change and the response change of explanatory variables. A higher precedence individual indicators should be selected to predict the future accurately. In this study, effectiveness of Jeju Island precedence indicators consists of constituents in the area, the consumer price index, services production index, mining and manufacturing production index. The average temperature of Seogwipo and credit card purchase amount is reviewed as an economic turning point consideration and time lag correlation analysis with real data. In addition, we suggest the proper reference cycle in Jeju composite precedence index and evaluate the configuration in leading indicators for Jeju by comparing national economic indicators. Based on the derived results, the current problems of Jeju Island precedence indicators will be illustrated and the improvement methods to estimate a regional composite index will be suggested.

• Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.153-159
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• 2006

The ark shell (or 'blood clam') Scapharca broughtonii is a filter-feeding bivalve that has red blood and inhabits waters approximately 10m in depth off the southern coast of South Korea. This study was part of a larger research project investigating the causes of death and restoration of shellfish resources, which are important aquaculture products in South Korea. We examined physiological responses related to survival, respiration, excretion, and amino acid changes as a result of changes in salinity. The 9-day median lethal salinity ($LS_{50}$) was 16.5 psu with confidence limits of 14.9-18.1 psu. At $25^{\circ}C$, the oxygen consumption and ammonia-nitrogen excretion rates were increased with decreases in salinity. Although the osmolality of individuals was acclimated within 2 h at 26.4 psu and 12 h at 19.8 psu, it took more than 5 days at a salinity of 13.2 psu, whereas no individuals acclimated and all died at a salinity of 6.6 psu. Of the amino acids present in the blood, taurine and alanine increased in response to decreased salinity. Tissues of the gill and the mid-gut gland were affected by decreasing salinity. These data will provide important fundamental information for examining the causes of mass mortality of shellfish in the summer.

• Journal of The Korean Society of Clinical Toxicology
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• v.11 no.2
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• pp.119-126
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• 2013

Purpose: The aim of this study was to evaluate the clinical characteristics and outcome of patients who presented to the emergency department (ED) with cardiotoxicity caused by ingestion of Himalayan mad honey. Methods: Medical records of 12 patients who presented to the ED from January 1, 2005 to December 31, 2012 with cardiotoxicity caused by ingestion of Himalayan mad honey were retrospectively reviewed. Results: The mean age of patients was 54.5 years and 58.3% were men. The median amount of mad honey ingested was 30.0 cc, and the mean time from ingestion to onset of symptoms was 39.4 minutes. All patients had hypotension and bradycardia upon arrival in the ED. The initial electrocardiogram showed sinus bradycardia in seven patients, junctional bradycardia in four patients, and atrial fibrillation with slow ventricular response in one patient. Four patients were treated with intravenous normal saline solution only. Eight patients were treated with intravenous normal saline solution and atropine sulfate in a dose ranging from 0.5 to 2.0 mg. Blood pressure and pulse rate returned to normal limits within 24 hours in all patients. Conclusion: Our study showed that all patients with cardiotoxicity caused by ingestion of Himalayan mad honey had severe hypotension, bradycardia, and bradyarrythmias, including sinus bradycardia and junctional bradycardia and all patients responded well to conservative treatment, including intravenous normal saline solution and intravenous atropine sulfate.

• Food Science of Animal Resources
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• v.32 no.1
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• pp.62-67
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• 2012

This study calculated kinetic parameters of Escherichia coli O157:H7 and developed a probabilistic model to estimate growth probabilities of E. coli O157:H7 on polyethylene cutting boards as a function of temperature and time. The surfaces of polyethylene coupons ($3{\times}5$ cm) were inoculated with E. coli O157:H7 NCCP11142 at 4 Log $CFU/cm^2$. The coupons were stored at 13 to $35^{\circ}C$ for 12 h, and cell counts of E. coli O157:H7 were enumerated on McConkey II with sorbitol agar every 2 h. Kinetic parameters (maximum specific growth rate, Log $CFU/cm^2/h$; lag phase duration, h; lower asymptote, Log $CFU/cm^2$; upper asymptote, Log $CFU/cm^2$) were calculated with the modified Gompertz model. Of 56 combinations (temperature${\times}$time), the combinations that had ${\geq}$0.5 Log $CFU/cm^2$ of bacterial growth were designated with the value of 1, and the combinations that had increases of <0.5 Log $CFU/cm^2$ were given the value 0. These growth response data were fitted to the logistic regression to develop the model predicting probabilities of E. coli O157:H7 growth. Specific growth rate and growth data showed that E. coli O157:H7 cells were grown at $28-35^{\circ}C$, but there were no obvious growth of the pathogen below $25^{\circ}C$. Moreover, the developed probabilistic model showed acceptable performance to calculate growth probability of E. coli O157:H7. Therefore, the results should be useful in determining upper limits of working temperature and time, inhibiting E. coli O157:H7 growth on polyethylene cutting board.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.7 no.2
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• pp.107-114
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• 2011

Dental extraction is potentially stress-inducing in many disabled patient. The body's response to dental stress involves the cardiovascular system(an increase in cardiovascular workload), the respiratory organ and the endocrine system(change in metabolism). To minimize the stress, the stress reduction method was established. The obtained contents were as follows: (1) Recognize the patient's degree of medical risk, (2) Complete medical consultation before dental therapy, (3) Schedule the patient's appointment in the morning, (4) Monitor and record preoperative and postoperative vital signs, (5) Use psychosedation during therapy, (6) Use adequate pain control during therapy, (7) Short length of appointment : do not exceed the patient's limits of tolerance, (8) Follow up with postoperative pain/anxiety control, (9) Telephone the risk patient later on the same day that treatment was given. Though the stress reduction method above was applied to the dental extraction in disabled patients with the advanced infected teeth, the complications(syncope, shock, bleeding & infection, etc.) may be occurred. For prevention of complications associated with the extraction, the authors treated the advanced infected teeth with endodontic drainage and incision & drainage before extraction. The final extraction and wound closure were then done after about 3 weeks.

• Journal of Forest and Environmental Science
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• v.29 no.3
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• pp.237-248
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• 2013

The legal basis for the systematic prevention and response to landslide hazards, and the rehabilitation of landslide-hit areas, was established through the amendment of the Forest Protection Act in August 2012. The most noticeable amendment to the Act is the inclusion of clauses associated with the designation and management of landslide-prone zones (including debris flow-prone zones). In this paper, we (1) introduce the clauses related to the designation and management of landslide-prone zones that were included in the amended Forest Protection Act, (2) examine their significance by reviewing the present status of related domestic laws and structural countermeasures such as sediment check dams for sediment-related disaster prevention, and (3) suggest the future directions of the procedure for the designation and cancellation of such zones, and their maintenance and institutional aspects. The establishment of an institutional device for the designation and management of landslide-prone zones has great significance in the aspect of (1) the establishment of a comprehensive management and prevention system for potential landslide-prone zones in forested areas where the hazard risk has been poorly recognized as compared with the flood risks in lowlands, and (2) the establishment of the basis for overcoming the limits of structural countermeasures according to limited budgets. To develop the designation and management system for landslide-prone zones, not only must present problems be addressed, but a cooperation system between the administration and local residents must also be established.

• Bulletin of the Korean Chemical Society
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• v.25 no.8
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• pp.1195-1201
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• 2004

Tyrosinase was covalently immobilized on platinum electrode according to the method we developed for laccase (Bull. Korean Chem. Soc. 2002, 23(7), 385) and p-chlorophenol, p-cresol, and phenol could be detected with sensitivities of 334, 139 and 122 nA/ ${\mu}M$ and the detection limits of 1.0, 2.0, and 2.5 ${\mu}M$, respectively. The response time ($t_{90\%}$) is 3 seconds for p-chlorophenol, and 5 seconds for p-cresol and phenol. The optimal pHs of the sensor are in the range of 5.0- 6.0. This sensor can tolerate at least 500 times repeated injections of p-chlorophenol with retaining 80% of initial activity. In case of tyrosinase and laccase co immobilized platinum electrode, the sensitivities are 560 nA/ ${\mu}M$ for p-phenylenediamine (PPD) and 195 nA/ ${\mu}M$ for p-chlorophenol, respectively. The sensitivity of the bi-enzyme sensor for PPD increases 70% compared to that of only laccase immobilized one, but the sensitivity for p-chlorophenol decreases 40% compared to that of only tyrosinase immobilized one. The sensitivity increase for the bi-enzyme sensor for PPD can be ascribed to the additional catalytic function of the co-immobilized tyrosinase. The sensitivity decrease for p-chlorophenol can be explained by the “blocking effect” of the co-immobilized laccase, which hinders the mass transport through the immobilized layer. If PPD was detected with the electrode that had been used for p-chlorophenol, the sensitivity decreased 20% compared to that of the electrode that had been used only for PPD. Similarly, if p-chlorophenol was detected with PPD detected electrode, the sensitivity also decreased 20%. The substrate-induced conformation changes of the enzymes in a confined layer may be responsible for the phenomena.

• Journal of the Korean Electrochemical Society
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• v.7 no.2
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• pp.83-88
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• 2004

[ $DeniLite^{TM}$ ] laccase immobilized Pt electrode was used for amperometric detection of some catechol derivatives and o-aminophenol (OAP) derivative by means of substrate recycling. In case of catechol derivatives, the obtained sensitivities are 85, 79 and $57 nA/{\mu}M$ with linear ranges of $0.6\~30,\;0.6\~30\;and\; 1\~25 {\mu}M$ and detection limits (S/N=3) of 0.2, 0.2 and $0.3{\mu}M$ for 3,4-dihydroxycinnaminic acid (3,4-DHCA), 3,4-dihydroxybenzoic acid (3,4-DHBA) and 3,4-dihydroxyphenylacetic acid (3,4-DHPAA), respectively. In case of OAP derivative, the obtained sensitivity is $237 nA/{\mu}M$ with linear range of $0.2\~15{\mu}M$ and detection limit of 70 nM for 2-amino-4-chlorophenol (2-A-4-CP). The response time $(t_{90\%})$ is about 2 seconds for each substrate and the long-term stability is around 40-50days for catechol derivatives and 30 days for 2-A-4-CP with retaining $80\%$ of initial activity. The optimal pHs of the sensor for these substrates are in the range of 4.5-5.0, which indicates that stability of the enzymatically oxidized product plays a very important role in substrate recycling. The different sensitivity of the sensor for each substrate can be explained by the electronic effect of the sugstituent on the enzymatically oxidized form.

• Journal of Korean Association for Spatial Structures
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• v.4 no.1 s.11
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• pp.49-59
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• 2004

A previous study evaluated the seismic response of typical multi-span simply supported (MSSS) and multi-span continuous (MSC) steel-girder bridges in the central and southeastern United States. The results showed that the bridges were vulnerable to damage resulting from impact between decks, and large ductility demands on nonductile columns. Furthermore, fixed and expansion bearings were likely to fail during strong ground motion. In this paper, several retrofit measures to improve the seismic performance of typical multi-span simply supported and multi-span continuous steel girder bridges are evaluated, including the use of elastomeric bearings, lead-rubber bearings, and restrainer cables. It is determined that iead-rubber bearings are the most effective retrofit measure for reducing the seismic vulnerability of typical bridges. While isolation provided by elastomeric bearings limits the forces into the columns, the added flexibility results in pounding between decks in the MSSS steel-girder bridge. Restrainer cables, which are becoming a common retrofit measure, are only moderately effective in reducing the seismic vulnerability of MSSS and MSC steel girder bridges.