• 대한화장품학회지
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• 제49권2호
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• pp.141-146
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• 2023

라세미 혼합물 (헤미에스테르)의 키랄 순도를 효율적으로 측정하기 위한 방법으로 이작용기 (티오우레아와 3차 아민)를 갖는 키랄 이동제 (3)에 대한 연구이다. 다양한 헤미에스테르와 키랄 이동제 (3)의 결합으로 형성된 부분 입체 이성질체에 의해서 헤미에스테르의 메톡시 양성자의 신호가 분명하게 분리되었다. ¹H NMR에서 헤미에스테르의 거울상 이성질체에 대한 분명한 신호 분리는 헤미에스테르의 카르보닐기와 키랄 이동제 (3)의 이작용기(티오우레아와 3차 아민) 사이의 수소 결합에 기인한다. 본 연구는 키랄 이동제 (3)를 사용하여 헤미에스테르의 키랄 순도를 빠르고 간단하게 결정할 수 있는 방법을 제공한다.

• 자원리싸이클링
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• 제30권6호
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• pp.12-18
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• 2021

수성가스 전환 반응은 가스화로 생성된 합성 가스에 수소 생산 증가와 H₂/CO 비율 제어를 위해 수증기를 첨가하는 가스화 후속 공정이다. 본 연구에서는 RPF(Refuse plastic fuel) 가스화 시스템의 합성가스를 대상으로 수성가스 전환 반응을 연구하였다. 수성가스 전환 반응은 촉매를 이용하여 high temperature shift(HTS) 와 low temperature shift(LTS) 반응에 대하여 lab scale 관형 반응기를 이용하여 반응 온도, steam/carbon ratio, 유량의 변화가 H₂ 생성과 CO 전환율에 미치는 영향을 조사하였다. 운전 온도는 HTS 시스템이 250-400℃, LTS 시스템이 190-220℃이며 steam/carbon ratio는 1.5-3.5로 변화시켰다. 반응 모의 가스의 농도는 RPF 합성가스의 농도를 기준으로 CO, 40vol%, H₂, 25vol%, CO₂, 25vol%이다. 반응 온도와 steam/carbon ratio가 증가함에 따라 CO 전환율 및 H₂ 생성량이 증가하고, 유량이 증가하면 촉매층의 체류시간 단축으로 CO 전환율과 H₂ 생성량이 감소하였다.

• 전기화학회지
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• 제2권1호
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• pp.23-26
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• 1999

백금$(Pt)/0.1M\;H_2SO_4$, 전해질 계면에서 교류임피던스 측정과 위상이동 방법을 사용하여 Langmuir 흡착등온식을 정성적으로 해석하였다. 위상이동$(\phi)$은 음전위(E<0)와 주파수(f)에 따르며, Pt 일전극(음극)에 흡착된 수소원자$(H_{ads})$의 표면피복율$(\theta)$에 반비례한다. 중간주파수대$(1\~100 Hz)$에서 위상이동 변화$(\phi\;vs.\;E)$는 Langmuir 흡착등온식$(\theta\;vs.\;E)$의 계산과 해석에 사용할 수 있는 실험적인 방법이다. $Pt/0.1M\;H_2SO_4$ 전해질 계면에서 흡착평형상수(K)와 표준자유에너지$({\Delta}G_{ads})$는 각각 $3\times10^{_4}$와 20.1kJ/mol이다.

• 대한간호학회지
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• 제21권2호
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• pp.129-149
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• 1991

Circadian rhythm is entrained in the 24-hour time interval by periodic factors in the environment, known as zeitgeber. But most rotating work schedules are outside the range of the entrainment of the pacemaker timing the human circadian sleep - wake cycle. It has been postulated that physiological and emotional disturbances occur in most human functions when the circadian rhythm is disturbed. So application of circadian principles to the design of shift schedules can aid in maintaining the temporal integrity of the circadian system and thereby minimize for the shift worker any detrimental consequences of circadian disruption. This study was a quasi-experimental study to test the effect of shift intervals for the clinical nurse on the circadian rhythm. Twenty nurses newly employed in general units of two hospitals were selected as an experimental group and twelve college nursing students as a control group. Both groups were selected according to an established criteria using a purposive sampling technique. Ten subjects were assigned to a weekly shift group and another ten to a biweekly shift group engaged in a semi -continuous shift schedule(sunday off) with a backward direction, that is, morning -evening - night shift. The control group worked a morning shift for 42 days. Oral temperature rhythm, waking tim, sleep - wake cycle, fatigue, and mental performance were measured during the experimental period. The data collection period was from April 30, 1990 to June 10, 1990. MANOVA, paired t-test, ANOVA, and Student Newman Keuls method were used for statistical analysis. The results are summarized as follows. 1. Phase delay in the acrophase of temperature rhythm was shown according to the backward rotating shift. A complete adaptation to work on the night shift was achieved between the sixth and ninth day of the night shift. 2. There was no difference in either waking time or sleep- wake cycle according to the duration of the working day for every shift group. Significant difference was found in the waking time and the sleep -wake cycle for subjects on the morning, evening, and night shift in both of the shift groups(weekly shift group : λ＝0.121, p＜0.01, λ＝0.112, p＜0.01, biweekly shift group : λ＝0.116, p＜0.01, λ＝0.084, p＜0.01). 3. There was no difference in fatigue between the first working day and the last working day for the control group and for the biweekly shift group. In the weekly shift group, physical fatigue was significantly different for the first day and the sixth day of the night shift(t＝-2.28, p＜0.05). Physical fatigue and total fatigue on the first day of the night shift showed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝5.79, p＜0.01, F＝4.56, p＜0.05). There was a significant difference between the shift groups and the control group(p＜0.05), Physical fatigue, neurosensory fatigue and total fatigue on the last day of the night shift showed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝12.65, p＜0.01, F＝7.77, p＜0.01, F＝9.68, p＜0.01). There was a significant difference between the shift groups and the control group(p＜0.05). 4. No difference in mental performance was seen between the first day and the last day of work in each case. An arithmatic test on the first day of the night shift revealed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝3.79, p＜0.05). There was a significant difference between the shift groups and the control group(p＜0.05) . The digital symbol substitution test and the arithmetic test on the last day of the night shift showed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝3.68, p＜0.05, F＝5.55, p＜0.01), and both showed a significant difference between the shift groups and the control group(p＜0.05). Accordingly, this study showed that during night duty, the waking time, sleep- wake cycle, and fatigue increased and mental performance decreased compared with morning and evening duty. It was also found that the weekly shift group had a higher fatigue score on the sixth day of night duty as compared to the -first day, but the waking time, sleep- wake cycle, and mental performance revealed no difference for the duration of the night duty or between shift groups, and complete adaptation of temperature rhythm was achieved between the sixth and ninth day of night duty. It is possible to conclude from these results that for intermediate circadian type in a healthy young woman, a biweekly shift system is more compatible with the circadian timing system than weekly shift system.

• 전자공학회논문지D
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• 제34D권9호
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• pp.1-6
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• 1997

A transmission type phase shift attenuator has a poor reflection characteristics at an output port. And that is controlled by the current, its dynamic rnage decreases due to the current limitation. In this paper, to avoid such disadvantages, a reflection type low phase shift attenuator has been designed and measured. As a result, at a center frequency (1855MHz), the sreflection type low pahse shift attenuator has an attenuation of 30dB, within the limit of 3 phase shift and less than -17dB reflection characteristics at both input and output ports. And it demonstrates the peformance of the reflection type low phase shift attenuator is better than the transmission type phase shift attenuator with the same measurement specifications.

• 대한화학회지
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• 제26권2호
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• pp.99-106
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• 1982

1-아세틸-1-메틸-2-시클로펜텐 화합물의 케톤 Chromophore를 나트릴, 카르보시산, 아미드 등의 group으로 대치하여 이들의 광화학반응을 검토한 결과 케튼 Chromophore에서 볼 수 있는 1,3-Acyl shift나 ODPM 반응은 일어나지 않았고 광화학적 중합 및 환원반응등 Chromophore를 변화시키므로서 광화학반응에 큰 변화를 보여주었다. 1-Cyano-1-methyl-2-cyclohexene의 경우도 Ketone chromophore와 비교하여 광화학 반응을 검토하였다.

• 한국직업건강간호학회지
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• 제8권1호
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• pp.22-41
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• 1999

This study intended to analyze the health promoting behaviors, compare their factors according to the shift pattern of duties of women workers who were working in the industrial workplace and present basic data in planning systematic and effective programs of health promotion for three-shift system and day-duty. Using Quota Sampling, 219 women workers were selected as subjects from 5 workshops which had 50 settled workers up to 300 and 10 factories which had more than 300 located in Taegu and Kyung-Book Province. Data were collected by means of questionnaire from September 12 to September 30, 1998. As the instruments of the study were used Health Promotion Lifestyle Profile(HPLP) which was adapted and adjusted by Seo, Y. O. for health promoting behavior, the one developed by Moon, J. S. (1990) for health-belief, the one developed by Sherer et al.(1982) and then adapted by Oh, H. S. for self-efficacy, and the one developed by Park, J. W. (1985) for social support. The analysis of data were performed with Cronbach's ${\chi}^2$-test, t-test, ANCOVA, Kendal tau, Pearson correlation, Stepwise Multiple Regression test using SPSS program. The results of the study are as follows : 1. There was a significant difference in age(${\chi}^2=32.46$, p=0.000), career (${\chi}^2=18.47$, p=0.000), working day(t=-3.18, p=0.000) by the shift pattern of duties in terms of socio-demographic characteristics. 2. There was a statistically significant difference between the two groups on the health promoting behaviors (t=2,52, p=0.012). The score of three-shift group on health promoting behaviors was 2.27, showing that it was lower by .13 than that of day-duty group(2.40). 3. ANCOVA involving age, career and working day as covariables, which had revealed significant difference before, showed that health promoting behaviors by the shift patterns of duties was significantly different(F=4.88, p=0.028). 4. In consideration of variables that have an influence on health promoting behavior by the shift pattern of duties, social support occupied 19.4% of health promoting behavior in the three-shift group and 22.5% including the sense of self-efficacy. In the day-duty group, social support occupied 34.4% of health promoting behavior. 5. The score of three-shift group(2.94) was significantly lower than that of day-duty group(3.12) in the perceived benefit of health-belief(t= -3.29, p=0.001), while the score of three-shift group (2.48) was significantly higher than that of day-duty group(2.24) in the perceived barrier (t=4.22, p=0.000). In the sense of self-efficacy(t=-4.20, p=0.000), the score of three-shift group(3.24) was significantly lower than that of day-duty group(3.53) while in social support(t=-4.56, p=0.000) the one of three-shift group(2.64) was significantly lower than that of day-duty group(2.88). The suggestions are as follows on the basis of the results of this study : 1. It is required to develop health promoting program that takes the shift pattern of duties of women workers into consideration. In addition, there are special demands on developing nursing strategies for health promoting behavior of three-shift workers. 2. It is required to develop specific strategies for social support which is the most significant factor to the health promoting behavior for women workers. 3. It is necessary to develop some programs for improving the sense of self-efficacy, social support, and health-belief of three-shift workers. To achieve these tasks, industrial nurses should play an active role and improve the ability of self-health care of women workers.

• 대한화학회지
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• 제32권6호
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• pp.513-519
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• 1988

헥사메틸벤젠과 1,3,5-트리니트로벤젠과의 사이에 전하이동착물의 안정도에 미치는 압력과 온도의 영향을 사염화탄소용액내에서 분광광도법으로 연구하였다. 압력은 1, 200, 500, 1000, 1400 bar. 온도는 25, 40, $50^{\circ}C$사이에서 측정하였다. 착물의 평형상수는 압력 및 온도 증가와 더불어 증가 또는 감소하고 흡수계수는 대체로 증가함을 알았다. 이들 각 평형상수로부터 착물형성에 따른 부피, 엔탈피, 자유에너지 및 엔트로피 변화량을 구하였다. 도한 압력 증가에 의한 red-shift, 온도 증가에 의한 blue-shift 현상 및 압력 변화에 의한 진동자세기의 관계를 열역학함수와 관계지어 설명하였다.

• 근관절건강학회지
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• 제21권2호
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• pp.135-144
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• 2014

Purpose: The purpose of this study was to analyze and clarify the concept of shift work maladaptation syndrome and to facilitate development of interventions for the shift work adaptation. Methods: This study used Walker and Avant's concept analysis process. Results: Shift work maladaptation syndrome can be defined as the following attributes: 1) destruction of the circadian rhythm, 2) existence of a threshold, 3) individual characteristics (year of career, type of personality, and type of coping) 4) somatization, and 5) negative emotional conditions. The antecedents of shift work maladaptation syndrome consist of counterclockwise shift work, irregular shift cycle, night work which is breaking circadian rhythm, and lifestyle changing. The consequences as a result of shift work maladaptation syndrome are deterioration of health (gastrointestinal, neuro-psychic, cardiovascular function), reduction of social relationships, and turnover or resign. Conclusion: The results of this study can be useful as the foundation of shift work adaptation implementation.

• 대한수학회보
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• 제57권1호
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• pp.81-93
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• 2020

Let m ∈ ℕ₀, p > 1 and $${\alpha}^{[m,p]}(x)\;:\;{\sqrt{x}},\;\{{\sqrt{\frac{(m+n-1)p-(m+n-2)}{(m+n)p-(m+n-1)}}}\}^{\infty}_{n=1}$$. In this paper, we consider the backward extensions of Bergman-type weighted shift W_α^[m,p](x). We consider its subnormality, k-hyponormality and positive quadratic hyponormality. Our results include all the results on Bergman weighted shift W_α(x) with m ∈ ℕ and $${\alpha}(x)\;:\;{\sqrt{x}},\;{\sqrt{\frac{m}{m+1}},\;{\sqrt{\frac{m}{m+2}},\;{\sqrt{\frac{m+2}{m+3}},{\cdots}$$.