• 월간산업보건
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• 통권90호
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• pp.56-57
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• 1995

• 환경기술인
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• 통권170호
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• pp.26-31
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• 2000

• 환경기술인
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• 통권171호
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• pp.30-35
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• 2000

• 환경기술인
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• 통권172호
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• pp.28-31
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• 2000

• 한국농공학회논문집
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• 제58권3호
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• pp.1-12
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• 2016

The objective of this study is to analyze the relationship between stream water quality of TN (total nitrogen), TP (total phosphorus), and BOD (Biochemical Oxygen Demand) and TDI (Trophic Diatom Index) score determined by physico-chemical factors, biomass, and standing crops of epilithic diatoms, and to estimate the required amount of ecological streamflow for good water environment of Trophic Diatom. For the main stream of Chungju dam watershed of South Korea, total 100 field data of 3 years (2008~2010) measured in May and September were used to derive the relationship between water quality and TDI. Trophic Diatom had high correlation (0.55 determination coefficient) with TN. Using the relationship, the required streamflow was evaluated by using the Soil Water Assessment Tool (SWAT) for good Trophic Diatom water environment through T-N water quality maintenance. The SWAT simulated 8 years (2003~2010) stream discharges and T-N water quality along the main stream. From present garde C (score range: 30.0~45.0) to grade A (score above 60.0) of TDI, the May needs additional streamflow of $63.1m^3/sec$ (+36.7 % comparing with the present streamflow of $172.0m^3/sec$) at the watershed outlet.

• 한국염색가공학회지
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• 제8권2호
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• pp.1-7
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• 1996

Thermotropic liquid-crystalline polyurethanes were synthesized by the polyaddition reaction of such para-substiuted diisocyanate monomer as 1,4-phenylene diisocyanate(1,4-PDI) and 2,5-tolylene diisocyanate(2,5-TDI), with 4,4'-bis($\omega$-hydroxyalkoxy)biphenyls(BPm: $HOC_{m}OC_{6}H_{4}C_{6}H_{4}OC_{m}H_{2m}OH$; m is the carbon number of the hydroxyalkoxy group). These polyurethanes have mesogenic biphenyl units in the main chain. Properties of polymers were studied by differential scanning calorimetry, wide-angle X-ray scattering, thermogravimetic analysis, polarizing microscopy, and infraed spectroscopy. DSC thermograms for these polymers exhibited two endothermic peaks corresponding to phase transitions of melting and isotropization. Mesomorphic behavior of the polyurethanes were also observed under the polarizing microscope. For example, polyurethane 2,5-YDI/BP5 with [$\theta$]=0.44 prepared from 2,5-TDI and BP5 exhibited a liquid crystalline phase from 194 to 205$^{\circ}C$. Infrared spectrum study indicated that the hydrogen bonding between urethane linkages affected the mesomorphism. The thermostabilities of polyurethanes 2,5-TDI/BP5 and 1,4-PDI/BP5 were measured at a heating rate of 1$0^{\circ}C$/min in air. The temperatures of 5% weight loss for 2,5-TDI/BP5 and 1,4-PDI/BP5 were 297 and 334$^{\circ}C$, respectively.

• 한국환경보건학회지
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• 제22권2호
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• pp.32-42
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• 1996

This study was performed to evaluate accuracy and precision of filter method and impinger method for analyzin airborne isocyanates in mixture (2, 6-TDI, HDI, 2, 4-TDI, MDI). Filter method was performed using the OSHA Method 42 and impinger method using the NIOSH Method 5521. The samples were analyzed by high performance liquid chromatography-ultraviolet detector (HPLC-UVD). After the optimum operating conditions for each method were investigated, samples with various concentration levels were quantified at the conditions. The precision was expressed by the pooled coefficient of variation(C.V.) and the accuracy by overall accuracy. The results are summarized as follows: 1. The optimum condition of filter method was determined at 35/65 ACN/buffer (0.01 M ammonium acetate) in mobile phase. And in case of impinger method, it was at 30/70 ACN/buffer(0.2 M sodium acetate). The effect of concentrations of acetate on the separation of the peaks was not significant, but, the effect of ACN/buffer ratio was significant. 2. The correlation coefficients for the two methods were above 0.9 in all isocyanate compounds. Average recovery efficiencies for 2, 6-TDI, HDI, 2, 4-TDI and MDI in filter method were 92.4%, 102.6%, 87.3% and 101.0%, respectively. Those in impinger method were 106.6%, 106.7%, 99.0% and 103.6%, respectively. As a result, the recovery efficiency of impinger method was higher than those of filter method in analyzing isocyanate compounds. 3. The pooled coefficients of variations of the methods were slightly higher than expected. The overall accuracies of the methods were within $\pm 25%$ for each isocyanate compound. Since these results satisfy NIOSH criteria, the accuracy of the experiment is appropriate. 4. As seen above, impinger method is more efficient than filter method. But, there are many disadvantages in impinger method. Therefore, solid sorbent such as a glass fiber filter must be developed in order to have the high efficiency not less than that of impinger method in the future.

• Journal of Trauma and Injury
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• 제32권4호
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• pp.210-219
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• 2019

Purpose: Traumatic diaphragmatic injury (TDI) is no longer considered to be a rare condition in Korea. This study investigated differences in the prevalence of accompanying injuries and the prognosis in patients with traumatic diaphragmatic damage according to the mechanism of injury. Methods: We retrospectively reviewed the medical records of patients with TDI who were seen at a regional emergency medical center from January 2000 to December 2018. Among severe trauma patients with traumatic diaphragmatic damage, adults older than 18 years of age with a known mechanism of injury were included in this study. Surgery performed within 6 hours after the injury was sustained was defined as emergency surgery. We assessed the survival rate and likelihood of respiratory compromise according to the mechanism of injury. Results: In total, 103 patients were analyzed. The patients were categorized according to whether they had experienced a penetrating injury or a blunt injury. Thirty-five patients had sustained a penetrating injury, and traffic accidents were the most common cause of blunt injuries. The location of the injury did not show a statistically significant difference between these groups. Severity of TDI was more common in the blunt injury group than in the penetrating injury group, and was also more likely in patients with respiratory compromise. However, sex, the extent of damage, and the initial Glasgow coma scale score had no significant relationship with severity. Conclusions: Based on the findings of this study, TDI should be recognized and managed proactively in patients with blunt injury and/or respiratory compromise. Early recognition and implementation of an appropriate management strategy would improve patients' prognosis. Multi-center, prospective studies are needed in the future.

• 공업화학
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• 제8권2호
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• pp.308-314
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• 1997

폴리우레탄 전선도료 제조시의 TDI와 MDI의 blocking 반응에 미치는 촉매와 blocking reagents(BR)의 영향에 대하여 조사하였다. 1,4-diazabicyclo[2.2.2]octane(DABCO)와 tetramethyl guanidine(TMG)와 같은 촉매들은 NCO의 blocking 반응을 완결시키는데 필요한 것으로 나타났다. TMG는 DABCO에 비해 매우 빠른 반응속도를 보였다. TMG의 농도는 1%까지 반응도에 대하여 정량적으로 비례하였다. DABCO의 경우는 0.25%의 농도에서 가장 높은 반응도를 나타내었다. BR의 입체영향을 알아보기 위해 phenol, p-cresol, m-cresol, o-cresol, 2,4-xylenol과 같은 BR 등을 사용하였다. 예측한대로 입체장애가 적은 BR이 높은 반응도를 보였다. 또한 이 반응 시스템에서는 온도와 BR의 농도가 증가할수록 반응도가 증가하였다.

• 환경영향평가
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• 제21권2호
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• pp.229-238
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• 2012

This research was to examine the physiochemical factors and the attached diatoms of ecological wetland in Paju from August 2010 to May 2011. As a result of physicohemical water quality assessment, the water temperature did not fluctuate much due to ample riparian vegetation and aquatic plants growing at the site. Due to the effect of Han River Estuary, site 4, 5 and 6 had high electricity conductivity. The BOD concentration was high at site 2, 3, and 4 caused by decrease in water quantity and inflow of polluted water. At all sites, T-N and T-P concentrations ranged from eutrophic to hypertrophic status. At the downstream, the T-N and T-P concentrations decreased by inhabiting aquatic plant. Total of 98 taxa of attached diatoms were found. As for dominant taxa, Achnanthes convergens, A. minutissima, Gomphonema gracile, G. parvulum, Melosira varians, Navicula seminulum, N. minima, N. pseudolanceolata, Nitzschia amphibia, N. palea, Surirella minuta and Synedra ulna var. fragilariodes appeared. The result of biological assessment of water quality rated the sites B(suboptimal)~D(poor) during seasons of low water temperature, Fall and Winter, with DAIpo ranging 24.1~68.2 and TDI of 48.4~85.6. During Spring and Summer, all sites were rated D(poor) with DAIpo lower than or equal to 40, and TDI above or equal to 70. The biological assessment of water quality at the research site showed inferior TDI result compared to that of DAIpo.