• 펄프종이기술
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• 제33권5호
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• pp.1-11
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• 2001

In the past, abundant and clean water was available for paper mills'use. However, the growth of population and industry made water less available nowadays. Also, environmental regulation limits wastewater discharge, which affects mill operation cost. Therefore, paper mills are under pressure to use more recycled water and mill system closure. As a result, chemical and physical parameters of water are changing and new environment if being created for microorganisms in paper mill system as well. The more soluble or suspended organic materials are increased as more water is recycled and less or scarce dissolved oxygen is available, depending on the degree of recycled water usage. Microorganism flora ill paper mill system will be a1so shifted according to the environmental change of mill system. Anaerobic bacteria, including sulfate reducing bacteria (SRB), will be dominant in the system as very low or almost no oxygen available in the system. Nevertheless, it is common in domestic paper mills that employ the same and old biocides as a means of microbial control, and microbiological control is often less recognized or even neglected. The right biocide selection for increased reductive environment of mills is critical for operation and estimated loss from paper quality defects such as sheet break, holes due to microbiological cause is tremendous compared to the microbiological control cost. It is imperative to investigate and diagnosis the environmental change of mills for right control of cumbersome microorganisms. Several useful diagnosis tools, including new technology employing OFM(Optical Fouling Monitor) in situ, are illustrated.

• 한국수자원학회논문집
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• 제35권6호
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• pp.753-762
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• 2002

본 연구에서는 치수안전도의 정확한 평가는 물론 자연환경에 대한 평가에 중요한 하천식물군락에 주목하였다. 특히, 본 연구에서는 하천식물군락과 유사거동에 따른 하도변화와의 상관관계의 규명에 관심을 두었다. 하도수리학 관점에서 하천내 식생분포 특성에 대한 하도현장을 조사한 결과, 하도변화를 야기하는 여러 물리적 요인이 있지만, 하천식생에 의한 하도변화, 특히 하천식물군락에 의한 유사퇴적이 하상변동을 야기시키고 있음이 확인되었다. 이를 수리학적으로 규명하기 위하여 수리모형실험을 실시하였다. 실험에서 하상경사 1/200인 자갈하천에 우점하는 달뿌리풀을 대상으로 하였다. 실험의 내용은 평균입경 0.3 mm의 소류사를 총 1 시간동안 27 kg을 균등하게 공급한 결과, 거의 동일한 수리량 조건하에서 식물군락의 밀도와 배치에 따라 흐름의 변화와 퇴적/세굴양상이 분명히 다르게 나타났다. 따라서, 하도내 퇴적 및 세굴이 하천식물군락의 분포 특성에도 영향을 미치므로 하천식물군락과 유사거동에 따른 하도변화는 상호 밀접한 관계가 있을 것으로 평가할 수 있었다.

• 대한기계학회논문집B
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• 제20권3호
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• pp.988-1004
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• 1996

The characteristics of flow and oxygen concentration are numerically studied in Czochralski 8" silicon crystal growing process considering radiative heat transfer. The analysis of net radiative heat flux on all relevant surfaces shows growing crystal affects the heater power. Furthermore, the variation of the radiative heat flux along the crystal surface in the growing direction is confirmed and should be a cause of thermal stress and defect of the crystal. The calculated distributions of temperature and, heat flux along the wall boundaries including melt/crystal interface, free surface and crucible wall indicate that the frequently used assumption of the thermal boundary conditions of insulated crucible bottom and constant temperature at crucible side wall is not suitable to meet the real physical boundary conditions. It is necessary, therefore, to calculate radiative heat transfer simultaneously with the melt flow in order to simulate the real CZ crystal growth. If only natural convection is considered, the oxygen concentration on the melt/crystal interface decreases and becomes uniform by the application of a cusp magnetic filed. The heater power needed also increases with increasing the magnetic field. For the case of counter rotation of the crystal and crucible, the magnetic field suppresses azimutal flow produced by the crucible rotation, which results in the higher oxygen concentration near the interface.

• 대한한의학원전학회지
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• 제21권1호
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• pp.43-62
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• 2008

After parturition, woman in childbed's health can grow worse. Because when woman in childbed gives birth, Genital organ can be damaged, and lost a lot of blood, and also consume a lot of physical strengths. So, after parturition, woman in childbed is easy to fall in disease if do not take care in health specially. So after parturition, woman in childbed should be careful in stress, sleep, food etc. This thesis described Postpartum Spasm[痙病], Oppressive Feeling and Dizziness[鬱冒], Constipation[便秘], Abdominal Pain[腹痛], Diarrhea[下利], Annoyance[煩亂] and Vomitting Sickness[嘔逆]. Postpartum Spasm[痙病]'s major symptom is rigided body. This disease corresponds to Tetanus in modem medicine, and bacterial infection is assumed for cause. By Oriental medicine, after parturition, when blood is lacking, if patient takes wind, this disease breaks out. Oppressive Feeling and Dizziness[鬱冒]'s major symptom is dizzy head and gloomy eye. After parturition, when blood is lacking, if patient sweats too much and take cold, this disease breaks out. After parturition, if patient consumes a lot of resins of human body, Constipation[使秘] breaks out. There are four causes to Abdominal pain[腹痛]. First, due to deficiency and cold treats by Danggwisaenggangyangyuktang(當歸牛薑羊肉湯). Second, due to stagnation of Gi(氣) treats by Jisiljakyaksan(枳實芍藥散). Third, due to blood stasis treats by Ha-eohyeoltang(下瘀血湯). Fourth, due to lochiorrhea treats by Daeseunggitang(大承氣湯). After parturition, Annoyance[煩亂] and Vomitting Sickness[嘔逆] due to fever of difficiency treat by Jukpidaehwan(竹皮大丸). After parturition, Febrile diarrhea[熱性下利] treats by Baekduonggagamchoagyotang(白頭翁加甘草阿膠湯). This disease is similar with present Bacillary Dysentery. After parturition, Exteroceptive disease due to taking wind treats by Yangdaltang. Due to wind and fever treats by Jukyeoptang(竹葉湯).

• 대한불안의학회지
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• 제14권2호
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• pp.71-79
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• 2018

Objective : Several earlier studies have reported similar symptoms in patients with posttraumatic stress disorder (PTSD) who have been repeatedly exposed to relevant media after disasters and trauma. This study aimed to examine the effects of indirect trauma experience through media rather than direct traumatic events on an individual's social life. Methods : Five hundred and fifty-four individuals participated in our online, self-reported questionnaire survey. All subjects were asked to complete a demographic questionnaire, Posttraumatic Diagnostic Scale, Beck Depression Inventory, the Impact of Event Scale-Revised, State-Trait Anxiety Inventory, Korean version of Alcohol Use Disorder Identification Test, Patient Health Questionnaire-15, Suicidal Behaviors Questionnaire-Revised. Participants were assessed in regards to their experience of violent media exposure within the past three months. Results : Data from our study indicates that the group exposed to violent media had significantly higher perceived stress, physical symptoms, insomnia, and suicide ideation in comparison to the control group. Among the major symptoms of PTSD, the proportion of intrusion symptoms was relatively high in the media exposed group. Conclusion : This suggests that indirect trauma caused by media exposure could cause post-traumatic stress symptoms. The PTSD caused by indirect trauma may have slight differences from the PTSD caused by direct trauma. Therefore, it is necessary to understand, prevent, and control the adverse effects of media.

• 시큐리티연구
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• 제56호
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• pp.165-185
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• 2018

금융산업은 일상 국민 생활경제와 매우 밀접한 관련이 있다. 따라서 저축은행 사태와 같이 금융기관 임직원들에 의한 횡령, 배임 등 부정행위(fraud)가 발생할 경우, 신용경색과 연쇄파산 등 민생경제에 심대한 악영향을 끼칠 수 있다. 이에 외국에서는 금융산업 보안의 중요성이 특히 강조되고 있고, 물적, 인적, 사이버를 통합하는 융합보안(converged security)으로 발전하고 있다. 본 연구는 우리나라 은행권에서 내부 임직원들에 의해 발생하는 부정행위를 방지하는데 목적이 있다. 이를 위하여, 리스크 관리(risk management) 업무를 담당하고 있는 은행권 임직원, 금융 정책수립 및 규제기관 담당자, 보안전문가 등 총 16 명에 대하여 반구조화된 심층 인터뷰(in-depth semi-structured interview)를 실시하였다. 수집된 데이터를 개인, 조직, 사회 문화적 레벨 등, 세 가지 계층화 수준에서 분석하였고, 이를 바탕으로 금융산업보안(financial industry security)의 발전과 금융권 내부부정 행위 방지를 위한 정책적 권고사항들을 도출하였다.

• 자원환경지질
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• 제52권5호
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• pp.471-484
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• 2019

액상화는 반복적인 전단력 혹은 강한 충격으로 인해 실트-모래로 구성된 미고결 퇴적층내 공극수압이 증가하여 전단강도를 상실함에 따라 미고결퇴적층이 액체처럼 거동하는 현상이다. 액상화는 미고결 퇴적층의 물리적 특성인 입도, 느슨함, 지하수위, 지층의 심도, 연령, 액상화 발달 유무 등과 밀접한 관련이 있으며 지표균열, 사태 및 연질퇴적변형 구조의 형성을 야기한다. 연질퇴적변형구조는 다양한 변형원인(trigger)에 의해 퇴적물의 전단강도가 감소함에 따라 퇴적물의 하중 등과 같은 변형동력(driving forces)이 발생하여 액상화, 요변성과 이에 수반된 유체화로 대표되는 변형기작(deformation mechanism)을 통해 형성된다. 이러한 변형구조는 퇴적작용이나 지진과 같은 지질학적 사건에 의해 발생하기 때문에 퇴적분지에서 발생하였던 지질학적 사건을 이해하는데 있어 중요한 역할을 한다. 이 뿐만 아니라 지진에 의하여 유발된 연질퇴적변형구조는 퇴적동시기성 구조운동을 이해할 수 있으며 지표파열을 수반하지 않는 피해 유발지진(> Mw 5.0)에 대한 고지진정보를 제공한다.

• 한국항행학회논문지
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• 제23권5호
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• pp.444-451
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• 2019

본 논문에서는 항공기 탑재장비의 RS-170a 영상 신호에 대한 EMI 및 낙뢰 간접영향에 대한 보호 대책을 설명한다. 항공기 탑재장비는 외부 환경으로부터 발생하는 전자파 간섭과 항공기 낙뢰 피격시 발생하는 낙뢰 간접영향으로 부터 발생하는 서지 전압에 의해 장비의 오작동이나 물리적 손상의 위험에 노출되어있다. 이러한 위험으로부터 장비를 보호하기 위해서는 전자파 간섭 및 간접 낙뢰 효과에 대한 보호 설계를 장비에 적용해야 하는데, 신호의 전압이 낮고 주파수 대역이 높을수록 보호 회로에 의한 신호 왜곡이 문제가 된다. 따라서 본 논문에서는 EMI 및 낙뢰 간접영향에 대한 일반적인 보호 설계 방법과, RS-170a 신호를 기준으로 보호 설계 적용에 따른 영상 신호 왜곡 현상을 최소화하기 위한 고려 사항을 소개한다. 그리고 이 과정에서 논한 고려 사항을 적용해 실제 장비 설계를 개선한 사례를 소개한다.

• Smart Structures and Systems
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• 제19권1호
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• pp.105-113
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• 2017

A microstructure-dependent dynamic model for silicon nanobeams with axial motion is developed by considering the effects of nonlocal elasticity and surface energy. The nanobeam is considered to subject to both transverse and longitudinal loads arising from nanostructural surface effect and all positive directions of physical quantities are defined clearly prior to modeling so as to clarify the confusions of sign in governing equations of previous work. The nonlocal and surface effects are taken into consideration in the dynamic behaviors of silicon nanobeams with axial motion including circular natural frequency, vibration mode, transverse displacement and critical speed. Various supporting conditions are presented to investigate the circular frequencies by a numerical method and the effects of many variables such as nonlocal nanoscale, axial velocity and external loads on non-dimensional circular frequencies are addressed. It is found that both nonlocal and surface effects play remarkable roles on the dynamics of nanobeams with axial motion and cause the frequencies and critical speed to decrease compared with the classical continuum results. The comparisons of the non-dimensional calculation values by present and previous studies validate the correctness of the present work. Additionally, numerical examples for silicon nanobeams with axial motion are addressed to show the nonlocal and surface effects on circular frequencies intuitively. Results obtained in this paper are helpful for the design and optimization of nanobeam-like microstructures based sensors and oscillators at nanoscale with desired dynamic mechanical properties.

• Smart Structures and Systems
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• 제19권1호
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• pp.1-10
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• 2017

The operation of subway trains induces secondary structure-borne vibrations in the nearby underground spaces. The vibration, along with the associated noise, can cause annoyance and adverse physical, physiological, and psychological effects on humans in dense urban environments. Traditional tethered instruments restrict the rapid measurement and assessment on such vibration effect. This paper presents a novel approach for Wireless Smart Sensor (WSS)-based autonomous evaluation system for the subway train-induced vibrations. The system was implemented on a MEMSIC's Imote2 platform, using a SHM-H high-sensitivity accelerometer board stacked on top. A new embedded application VibrationLevelCalculation, which determines the International Organization for Standardization defined weighted acceleration level, was added into the Illinois Structural Health Monitoring Project Service Toolsuite. The system was verified in a large underground space, where a nearby subway station is a good source of ground excitation caused by the running subway trains. Using an on-board processor, each sensor calculated the distribution of vibration levels within the testing zone, and sent the distribution of vibration level by radio to display it on the central server. Also, the raw time-histories and frequency spectrum were retrieved from the WSS leaf nodes. Subsequently, spectral vibration levels in the one-third octave band, characterizing the vibrating influence of different frequency components on human bodies, was also calculated from each sensor node. Experimental validation demonstrates that the proposed system is efficient for autonomously evaluating the subway train-induced ambient vibration of underground spaces, and the system holds the potential of greatly reducing the laboring of dynamic field testing.