• 한국물환경학회지
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• 제16권4호
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• pp.523-532
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• 2000

The purpose of this study was to investigate the effects of the hydraulic retention time (HRT) and organic loading rate (OLR) on microbial characteristics and treatment efficiency in sewage treatment using aerated submerged biological filter (ASBF) reactor. This reactor combines biodegradation of organic substrates by fixed biomass with a physical separation of biomass by filtration in a single reactor. Both simulated wastewater and domestic wastewater were used as feed solutions. The experimental conditions were a temperature of 17 to $27^{\circ}C$, a hydraulic retention time of 1 to 9hr, an organic loading rate of 0.47 to $3.84kg\;BOD/m^3{\cdot}day$ in ASBF reactor. This equipment could obtain a stable effluent quality in spite of high variation of influent loading rate. Total biomass concentration. biofilm thickness and biofilm mass increased an exponential function according to the increasing OLR. The relationships between water content and biofilm density were in inverse proportion. The percentage of backwash water to influent flow was almost 9%. The separation efficiency of biomass was the percentage of 91 to 92 in ASBF reactor. The sludge production rates in feed solutions of simulated wastewater and domestic wastewater were 0.14~0.26 kg VSS/kg BODrem, 0.43~0.48 kg VSS/kg BODrem, respectively.

• Journal of Advanced Marine Engineering and Technology
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• 제15권3호
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• pp.57-65
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• 1991

The quenching of steels by water is one of the important problems in engineering for the applications of heat treatment or continuous casting process, but the fundamental researches by the theoretical approaches have not been satisfactorily improved yet. The very rapid cooling problems by the thermal conduction including the latent heat of phase transformation in steel and the transient boiling heat transfer of water on the surface of the steel covering from $850^{\circ}C$ to $20^{\circ}C$ are the key problems of heat treatment. The present quenching experiments are performed for the cylindrical specimens of carbon steel, S45C of diameters (12-30). Nonlinear transient heat conduction and transient boiling heat transfer problem of water on the surface of specimens is analyzed by the numerical method of inverse heat conduction problem. The conditions for the calculation are that the initial temperature of specimens is $820^{\circ}C$ and the cooling water in bath are $20^{\circ}C$,$40^{\circ}C$,$60^{\circ}C$,$80^{\circ}C$,$95^{\circ}C$ with no agitation.

• Current Photovoltaic Research
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• 제3권4호
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• pp.112-115
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• 2015

In this study, the surface of ITO films was modified using $N_2-O_2$ molecular plasma, and the effects of oxygen concentration in the plasma on the ITO surface properties were investigated. Upon plasma treatment of ITO films, the surface roughness of ITO films seldom changed up to the oxygen concentration in the range of 0% to 40%, while the roughness of the films slightly changed at or above the oxygen concentration of 60%. The contact angle of water droplet on ITO films dramatically changed with varying oxygen concentration in the plasma, and the minimum value was found to be at the oxygen concentration of 20%. The plasma resistance at this condition exhibited a maximum value, and the change of resistance showed an inverse relationship compared to that of contact angle. From these results, it was conjectured that the chemical reactions in the sheath of the molecular plasma dominated more than the physical actions due to energetic ion bombardment, and also the plasma resistance could be used as an indirect indicator to qualitatively diagnosis the state of plasma during the plasma treatment.

• Communications for Statistical Applications and Methods
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• 제29권2호
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• pp.177-191
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• 2022

This paper addresses the use of machine learning methods for causal estimation of treatment effects from observational data. Even though conducting randomized experimental trials is a gold standard to reveal potential causal relationships, observational study is another rich source for investigation of exposure effects, for example, in the research of comparative effectiveness and safety of treatments, where the causal effect can be identified if covariates contain all confounding variables. In this context, statistical regression models for the expected outcome and the probability of treatment are often imposed, which can be combined in a clever way to yield more efficient and robust causal estimators. Recently, targeted maximum likelihood estimation and causal random forest is proposed and extensively studied for the use of data-adaptive regression in estimation of causal inference parameters. Machine learning methods are a natural choice in these settings to improve the quality of the final estimate of the treatment effect. We explore how we can adapt the design and training of several machine learning algorithms for causal inference and study their finite-sample performance through simulation experiments under various scenarios. Application to the percutaneous coronary intervention (PCI) data shows that these adaptations can improve simple linear regression-based methods.

• 치위생과학회지
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• 제23권4호
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• pp.255-263
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• 2023

Background: This study used text mining techniques to determine public perceptions of dental fear, extracted keywords related to dental fear, identified the connection between the keywords, and categorized and visualized perceptions related to dental fear. Methods: Keywords in texts posted on Internet portal sites (NAVER and Google) between 1 January, 2000, and 31 December, 2022, were collected. The four stages of analysis were used to explore the keywords: frequency analysis, term frequency-inverse document frequency (TF-IDF), centrality analysis and co-occurrence analysis, and convergent correlations. Results: In the top ten keywords based on frequency analysis, the most frequently used keyword was 'treatment,' followed by 'fear,' 'dental implant,' 'conscious sedation,' 'pain,' 'dental fear,' 'comfort,' 'taking medication,' 'experience,' and 'tooth.' In the TF-IDF analysis, the top three keywords were dental implant, conscious sedation, and dental fear. The co-occurrence analysis was used to explore keywords that appear together and showed that 'fear and treatment' and 'treatment and pain' appeared the most frequently. Conclusion: Texts collected via unstructured big data were analyzed to identify general perceptions related to dental fear, and this study is valuable as a source data for understanding public perceptions of dental fear by grouping associated keywords. The results of this study will be helpful to understand dental fear and used as factors affecting oral health in the future.

• 한국잠사곤충학회지
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• 제17권2호
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• pp.97-100
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• 1975

추잠기의 적엽정도가 지조의 수량에 미치는 영향을 알기 위하여 시험을 한 바 다음과 같은 결과를 얻었다. (1) 추기에 있어서의 적엽의 영향은 조장이나 조률과 같은 형태적인 면보다는 조량과 같은 질적인 면에 더 크게 나타나고 있다. 2. 조량은 중간부적엽구를 제외하고는 추잠기의 적엽량과 반비례하여 무적엽구, 불반부적엽구, 중간부적엽구가 크고 상반부적엽구와 전적엽구는 작았는데 중간부적엽구는 추기의 적엽량이 많았는데도 조량이 컸다. (3) 춘잠기의 수량은 조량과 정비례의 관계에 있어 조량이 큰 무적엽구, 중간부적엽구, 하반부적엽구의 순위대로 많았고, 상반부적엽구, 전적엽구의 순으로 적었다. (4) 연간합계수량은 중간부적엽구가 가장 많아서 무적엽구에 비한다면 36％, 가행법인 전적엽구(상단 5잎 남기고)보다는 13％정도 많았다.

• 치위생과학회지
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• 제18권3호
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• pp.137-146
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• 2018

This systematic review aimed to investigate the effects of periodontal treatment on glycated hemoglobin A (HbA1c) levels in patients with type 2 diabetes who develop periodontal disease. The search of the MEDLINE, Embase, CINAHL, and Cochrane Library databases was completed on April 8, 2018. The study design was based on randomized clinical trials. Scaling and root planing was performed for the test group, whereas no periodontal treatment or simple oral training was performed for the control group. The main outcome variable was the change in HbA1c levels. We used the Review Manager statistical analysis software for the quantitative analysis of selected documents. Meta-analysis was performed using the inverse variance estimation method of the fixed-effect model to estimate the effects of periodontal treatment on HbA1c levels in patients with type 2 diabetes. A total of 1,011 documents were searched using search strategies, and 10 documents were included in the meta-analysis. The meta-analysis of the selected literature showed that periodontal treatment significantly reduced the HbA1c levels in patients with type 2 diabetes who develop periodontal disease (mean difference, -0.34; 95% confidence interval, -0.43 to -0.26; p<0.001). This study aimed to investigate the effects of periodontal treatment on HbA1c levels, which can be used as a basis for the increasing management of diabetic complications. To improve the quality of life and reduce the burden of medical expenses for patients with diabetes, periodontal disease management through nonsurgical periodontal treatment, such as scaling and root planing, is necessary.

• 정신신체의학
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• 제31권2호
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• pp.108-117
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• 2023

연구목적 신체 증상 장애(Somatic Symptom Disorder, SSD)는 다양한 신체 증상의 발현을 특징으로 하며, 현재까지 환자군 내에서 증상 심각도에 따른 자율신경계 활성의 차이에 대해서는 연구된 바가 거의 없다. 이에 본 연구에서는 신체 증상 장애 환자군에서 심박변이도(Heart Rate Variability, HRV) 차이를 검정하여 증상 심각도에 따른 자율신경계 변화를 반영하는 대표적 지표를 분석하였다. 방 법 2020년 9월 18일부터 2021년 10월 29일까지 강남세브란스병원 정신건강의학과에 내원했던 환자 중, DSM-5 진단 기준에 따라 SSD로 진단받은 환자 총 51명의 의무기록을 후향적으로 수집하였다. 이후, 집단 간 인구사회학 및 임상적 선택편의 보정을 위해 역확률 가중치(Inverse Probability Treatment Weighting, IPTW)를 적용하여 HRV 지표 차이 검정을 실시하였다. 결 과 신체 증상 심각도와 LF (nu), HF (nu), LF/HF, 그리고 SD1/SD2, Alpha1/Alpha2는 통계적으로 유의한 상관관계를 보였으며, IPTW 적용 후 비중증군은 27명(53.0%), 중증군은 24명(47.0%)로 보정되었고, 인구사회학적 요인 및 임상적 특성 차이가 유의미하지 않아 동질성이 확보되었다. 본 모형 분석 결과 고위험군일수록 시간 영역의 RMSSD (β=-0.70, p=0.003), pNN20 (β=-1.04, p=0.019), 주파수 영역은 LF (nu) (β=0.29, p<0.001), HF (nu) (β=-0.29, p<0.001), LF/HF (β=1.41, p=0.001), 그리고 비선형 영역에서는 SampEn15 (β=-0.35, p=0.014), SD1/SD2 (β=-0.68, p<0.001), Alpha1/Alpha2 (β=0.43, p=0.001)에서 유의미한 차이가 검정되었다. 결 론 신체 증상 심각도에 따른 HRV 지표의 차이는 시간과 주파수 영역, 그리고 비선형 영역 전반에서 검정되었으며, 신체 증상이 심할수록 교감신경의 과활성화 및 부교감신경의 저하를 시사하는 HRV 지표들이 유의미하게 높은 경향성을 보였다.

• 대한약리학회지
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• 제32권1호
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• pp.23-29
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• 1996

전통적인 수용체 이론에 따르면 상경적 길항제는 효현제와 수용체의 같은 부위에 작용하지만, 효능(efficacy)이 없기 때문에 생물학적 반응을 일으키지는 않는다. 그러나 최근에 발표되는 자료들에 따르면 모든 길항체의 효능(efficacy)이 0가 아니라 음수도 될 수가 있다고 생각된다. 이러한 음수의 효능을 갖는 약물을 역효현제라 부른다. 본 연구에서는 쥐의 cerebral cortex에서 얻은 membranes을 사용하여, $A_1$ 아데노신 수용체에 작용하는 역효현제를 인구하였다. 8개의 길항제로 알려진 약물들이 G단백에 대한 $[^{35}S]GTP_{\gamma}S$ 결합을 감소시키는 정도를 측정함으로써 역효현제의 특성을 검색하였다. 효현제에 의한 $[^{35}S]GTP_{\gamma}S$ 결합의 증가는 이틀 길항제틀에 의해 완전히 억제되었지만, 검색한 8개의 길항제는 두 군으로 구분되었다. DPCPX를 포함한 7개 길항제는 효현제 부재시의 basal $[^{35}S]GTP_{\gamma}S$ binding을 통계적으로 의의있게 감소시켜 역효현제의 특성을 나타내는 반면, CCS-15943은 basal $[^{35}S]GTP_{\gamma}S$ binding에 아무런 영향을 주지 않았다. NEM을 membranes에 처치하면 PIA에 의한 $[^{35}S]GTP_{\gamma}S$ binding이나 basal binding 둘다 감소하는데 이는 $[^{35}S]GTP_{\gamma}S$ binding의 상당부분이 G단백의 activated state를 나타내는 것을 알 수 있다. 또한 $[^3H]DPCPX$를 이용한 competitive binding assay에서 0.1 mM GTP는 효현제인 PIA의 apparent affinity를 감소시켰으며, DPCPX의 apparent affinity는 증가시키고, CGS-15943에는 아무런 영향을 미치지 않았다. 이것은 상기의 $[^{35}S]GTP_{\gamma}S$ binding의 결과를 뒤받침해 주는 결과라고 생각된다.

• 대한한방내과학회지
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• 제19권1호
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• pp.144-156
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• 1998

This study has been carried out to investigate the cause, pathological mechanism and treatment of symptoms regarded as the ischemic heart disease in Nei-jing(內經). I've got the following conclusions. 1. From the side of xing-bi(胸痺), the ischemic heart disease(IHD) was caused by that the energy in one's heart wasn't extended in the way of Yin-xie(飮邪), namely waste matter of human body and symptoms and treatment wern't written. 2. From the side of xin-bi (心痺), HID was catched by the mechanisms that the blood vessel is blocked. or the heart's blood was deficient owing to the mutation of mo-bi(脈痺), the lack of yang-ming(陽明) and excessive thoughts and worry and others. The symptoms were feeling oppressed in one's brest, palpitating, sudden dyspnea, the dryness of thorat, frequent belching and the fear by the inverse flow of the energy(氣). The treatment was that the yin(陰) was cured immediately, but the yang(陽) mustn't be attacked. 3. From the side of xing-tong(心痛), IHD was suffered from by mechanisms that following the han-sa(寒邪), namely the cold makes a invasion on humanbody, the vessel was blocked, spasm, filled and the amount of blood flow was poor, or caused by injury of vessel, the inverse flow and the disease of shi-dong(是動病) of shou-shao-xin-jing(手少陰心經) and so on. The pain was cramped into the upper and lower back or lower abdomen or throat and accompanied with nausea, abdominal dropsy, constipation, the impending of breathing and so on. The cure was mainly that acupuncture was applied at the jin-su(筋縮) region or meridian in relation to symptoms, but if the pain were severe, acupuncture mustn't be applied. The prog nosis was worse. 4. From the side of xing-tonge(心痛), IHD was divided into zhen-xing-tong(眞心痛) and jue-xing-tong(厥心痛), but pi-xiog-tong(脾心痛) and wei-xing-tong(胃心痛) out of jue-xing-tong(厥心痛) also included the symptoms of the digestive disease.