• 대한화학회지
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• 제32권6호
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• pp.588-592
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• 1988

키랄 보조제가 붙어있는 3-acyl-4(S)-isopropyl-1,3-thiazolidine-2-thione[4(S)-AITT]을 라세미 아민과 가아민 분해반응을 시켰을때 광학활성을 갖는 아미드(S-excess)와 아민(R-excess)이 얻어지는 입체 선택적인 반응이 관찰되었다. 이와같은 입체 선택적인 반응은 macrocyclic diamide, macrocylic sperimidine alkaloid, peptide 합성에 이용될 수 있다. 가아민 분해반응의 속도는 아민의 입체적인 영향을 많이 받았고 반응이 종료점은 노락색의 소실로 쉽게 관찰되었다. 4(S)-AITT는 4(S)-isopropyl-1,3-thiazolidine-2-thione과 carboxylic acid로부터 얻었다.

• Journal of Acupuncture Research
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• 제23권5호
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• pp.31-37
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• 2006

Objectives & Methods : We investigated the cases for which spleen tonifying Sa-Am acupuncture was applied in ${\ulcorner}$Sa-Am-chim-gu-jeong-jeon(舍巖鍼灸正傳)${\lrcorner}$ and classified them according to the concepts of cold-heat & deficiency-excess for a better understanding of the application of spleen tonifying Sa-Am acupuncture. Results : 1. Tonification of Spleen Sa-Am acupuncture can be used to treat heat syndromes such as deficient fire caused by collapse of the spleen qi, stagnation of evil qi or spleen yin deficiency, by way of tonifying spleen qi, activating the flow of qi and blood or harmonizing spleen yin and yang. 2. Tonification of Spleen Sa-Am acupuncture can be used to treat cold syndromes such as weakness of spleen yang by way of promoting fire to generate earth, strengthening spleen yang and raising the clear yang. 3. Tonification of Spleen Sa-Am acupuncture can be used to treat deficiency syndromes such as malnutrition or poor appetite caused by spleen deficiency by way of tonifying spleen qi. 4. Tonification of Spleen Sa-Am acupuncture can be used to treat excess syndromes such as stagnation of qi and blood, abdominal mass or toxication by way of tonifying spleen qi and promoting the flow of qi and blood.

• 대한전기학회논문지
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• 제43권4호
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• pp.613-619
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• 1994

Dielectric properties of Ba(ZnS11/3TTaS12/3T)OS13T+x ZnO(x=0, 0.4, 0.8, 1.0 wt%) ceramics have been investigated at microwave frequencies. With excess ZnO, the sinterability was improved and the dielectric constant($\varepsilon$S1rT) and the unloaded quality factor(QS1UT) were increased. The structure changed into hexagonal from pseudocubic as being annealed at 140$0^{\circ}C$ in excess ZnO composition. Also, the temperature coefficient of the resonant frequency ($\tau$S1fT) turned into (-)ppm/$^{\circ}C$ when sintered at 155$0^{\circ}C$ for 2 hours. But the specimen sintered in ZnO muffling showed increased density and $\varepsilon$S1rT but lowerde QS1uT. Among the specimen investigated, expecially the composition added with 0.4wt% excess ZnO showed the most optimum dielectric values ($\varepsilon$S1rT=28, QS1uT x f=120000GHz) better than those of original Ba(ZnS11/2T TaS12/3T)OS13T ceramics.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 지반조사위원회 봄 학술세미나
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• pp.37-46
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• 1998

Several researchers have developed a number of theoretical time factors to determine the coefficient of consolidation by biezocone excess pore water dissipation test in soft clay deposits. However, depending on the assumptions and analytical techniques, the estimated coefficient of consolidation could be in a considerably wide range even for a specific degree of consolidation. These solutions are obtained from an initial excess porewater pressure distribution which can be determined from. either the cavity expansion theory or the strain path method. The 야ssipation of the initial excess porelvater pressure has been usally simulated by means of linear-uncoupled consolidation analysis and then the dissipation curve is normalized by the initial excess porewater pressure for easy use. However. since there is no guidelines or rules on which method gives the best solution for obtaining the coefficient of consolidation from the dissipation curve, the final selection was only based on engineer's extrience and Judgements. Thus, such an arbitrary selection might be inappropriate for a specific site to characterize the consolidation behavior. In this paper, we reviewed various theoretical time factors and, based on this consideration, we mentioned needs for researches in selecting a specific solution that is compatible for Korean clays. Also we listed some source of errors that can be encountered in the procedure of dissipation analysis.

• 한국표면공학회지
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• 제42권4호
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• pp.186-189
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• 2009

In this study, niobium powder was made from potassium heptafluoroniobite($K_2NbF_7$) using sodium(Na) as a reductant and KCl, KF as a diluent based on the hunter metallothermic reduction method. The excesses of reductant were varied from 0%, 3%, 5% and 7%. When 7% excess of sodium was used, the un-reacted sodium remained in the reacted product. The niobium powder has been achieved by reducing 50 g of $K_2NbF_7$ with 5% sodium excess in a charge at a reduction temperature of $850^{\circ}C$. The proportion of fine fraction decreased appreciably and the yield of niobium powder improved from 65% to 85% with the increase of sodium excess. The average particle size of niobium powder is improved from 0.2 microns to 0.3 microns in the 5% excess sodium.

• 한국측량학회지
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• 제4권2호
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• pp.10-26
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• 1986

본 논문은 실체시 측정에 있어서 발생하는 과고감과 표고측정의 정밀도와의 상관관계를 실험에 의하여 구명하고자 한 것이다. 일반적으로 과고감이 크면 클수록 표고측정의 정밀도가 높아진다는 사실이 알려져 있을뿐, 정확한 구명이 되어 있지 않다. 따라서 본 연구에서는 과고감에 대한 이론을 재정립하고 이것을 실험에 의하여 구명하고저 하였다. 실험결과에 의하여 과고감과 표고측정의 정밀도는 직접 비예관계가 성립하고 과고감이 클수록 표고측정의 정밀도가 높다는 것을 알 수 있었다.

• Journal of Nutrition and Health
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• 제26권5호
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• pp.558-565
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• 1993

This study was carried out to observe the effects of dietary n-6, n-3 fatty acids and vitamin A levels on serum lipid contents and hepatic tissues in rats. Sixty eight male Sprague-Dawley rats were fed 6 different experimental diets for 6 weeks. The diets were composed of 10% of either corn oil or fish oil with three levels of vitamin A ; defient (1240IU/kg diet), adequate (4000IU/kg diet), excess(400,000IU/kg diet). It was observed that triglyceride content and lipoprotein ratio in serum were not affected by dietary fat types and vitamin A levels. However, total serum cholesterol contents were significantly lower in fish oil groups than in corn oil groups, which were not affected by vitamin A levels. Under light microscope, vitamin A excess groups showed pathological abnormalites, such as fatty change and inflammation of the hepatic tissues. There abnormalities were less severe in fish oil groups. These results suggested that fish oil could be a dietary factor lowering the serum lipid contents, and it seems to relieve the abnormal changes in liver induced by excess vitamin A.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.97-104
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• 2006

The centrifuge and 1-g shaking table tests were performed simultaneously to compare the dynamic behaviors of loose sands of same geotechnical properties. The prototype soils were 10 m thick liquefiable loose sands. The geometric scaling factors were 20 for 1-g and 40 for centrifuge tests. The excess pore pressure, surface settlement, and acceleration in the soil were measured at the same locations in the 1-g and centrifuge tests. The total excess pore pressure from development to dissipation was measured. In the centrifuge test, viscous fluid was used as the pore water to eliminate the time scaling difference between dynamic time and dissipation time. In the 1-g tests, the steady state concept was applied to determine the unit weight of the model soil, and two different time scaling factors were applied for the dynamic time and the dissipationtime. It is concluded that the 1-g tests can simulate the excess pore pressure of the prototype soil if the permeability of the model soil is small enough to prevent dissipation of excess pore pressure during shaking and the dissipation time scaling factor is properly determined.

• Safety and Health at Work
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• 제12권2호
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• pp.174-183
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• 2021

Background: Toluene diisocyanate (TDI) is a highly reactive chemical that causes sensitization and has also been associated with increased lung cancer. A risk assessment was conducted based on occupational epidemiologic estimates for several health outcomes. Methods: Exposure and outcome details were extracted from published studies and a NIOSH Health Hazard Evaluation for new onset asthma, pulmonary function measurements, symptom prevalence, and mortality from lung cancer and respiratory disease. Summary exposure-response estimates were calculated taking into account relative precision and possible survivor selection effects. Attributable incidence of sensitization was estimated as were annual proportional losses of pulmonary function. Excess lifetime risks and benchmark doses were calculated. Results: Respiratory outcomes exhibited strong survivor bias. Asthma/sensitization exposure response decreased with increasing facility-average TDI air concentration as did TDI-associated pulmonary impairment. In a mortality cohort where mean employment duration was less than 1 year, survivor bias pre-empted estimation of lung cancer and respiratory disease exposure response. Conclusion: Controlling for survivor bias and assuming a linear dose-response with facility-average TDI concentrations, excess lifetime risks exceeding one per thousand occurred at about 2 ppt TDI for sensitization and respiratory impairment. Under alternate assumptions regarding stationary and cumulative effects, one per thousand excess risks were estimated at TDI concentrations of 10 - 30 ppt. The unexplained reported excess mortality from lung cancer and other lung diseases, if attributable to TDI or associated emissions, could represent a lifetime risk comparable to that of sensitization.

• Geomechanics and Engineering
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• 제30권2호
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• pp.201-210
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• 2022

This paper presents a study regarding the influence of various water levels on the characteristics of subgrade mud pumping through a self-developed test instrument. The characteristics of mud pumping are primarily reflected by axial strain, excess pore water pressure, and fine particle migration. The results show that the axial strain increases nonlinearly with an increase in cycles number; however, the increasing rate gradually decreases, thus, an empirical model for calculating the axial strain of the samples is presented. The excess pore water pressure increases rapidly first and then decreases slowly with an increase in cycles number. Furthermore, the dynamic stress within the soil first rapidly decreases and then eventually slows. The results indicate that the axial strain, excess pore water pressure, and the height and weight of the migrated fine particles decrease significantly with a low water level. In this study, when the water level is 50 mm lower than the subgrade soil surface, the issue of subgrade mud pumping no longer exist.