단파장 자외선(254nm)에 노출된 고밀도 폴리에틸렌 수지의 카르보닐 지수(CI)와 기계적 물성 변화의 관계에 관한 연구

김창환 ( Chang Hwan Kim ),신진용 ( Jin Yong Shin ) 한국공업화학회 2013 공업화학 Vol.24 No.2

This paper studied the possibility to predict a mechanical property variation from changes in created carbonyl bands by irradiating the surface of high-density polyethylene with short-wavelength ultraviolet radiation of 254nm to induce a fast chemical degradation. The meaning of this study lies in checking whether a mechanical property change with the same chemical property as the induced optical deterioration is caused by using a UVC lamp with high photon energy instead of optical deterioration via xenon arc light source and outdoor exposure test via natural sunlight requiring a long time. The mechanical strength of high-density polyethylene checked by a tensile test and a creep destruction test showed a similar tendency with CI changes. In particular, the yield strength and elongation had a close relationship with the exposure time to ultraviolet radiation. Accordingly, this paper presented a method to grasp the mechanical property change outdoors requiring a long time more fast through the relationship between the mechanical property change and the carbonyl index using a UVC lamp causing the fast surface degradation.

디지털 치의학의 과거와 현재 그리고 미래

김창환,Kim, Chang Hwan 대한심미치과학회 2015 Journal of the Korean Academy of Esthetic Dentistr Vol.24 No.1

치과계에서 캐드캠이 보급되면서 본격적으로 사용한 지 15년이 넘었다. 코핑 정도의 역할에서 구치부 전부관으로 확대되었고, 최근에는 전치부에서도 많이 사용하는 추세이다. 장비의 발전도 비약적이었지만 지르코니아 블록의 발전이 가장 많이 이루어졌다. 개개인의 능력이나 경험 차에 의해 차이는 있을 수 있겠지만, 도재를 올리지 않고 지르코니아에 컬러링만으로도 얼마든지 색을 표현 할 수 있다. 또한 캐드 디자인 만으로도 표면의 질감을 표현하는 것에 우리가 알고 있는 만큼 가능하다. 본 논문에서는 이러한 디지털 치과학의 변천과정을 정리해 보고자 한다. Since its introduction to the dentistry, the CAD/CAM technology has been used over fifteen years. The application of CAD/CAM started from coping fabrication, expanded to the posterior full crown, and anterior restoration manufacture has also become widespread recently. While the development of machine was rapid, the advance of zirconia block was the fastest. Although some differences exist among individuals, the various natural tooth color can be expressed through the zirconia coloring itself without porcelain build up. And the texture characteristics can be reproduced just by CAD design. In this article, the development history of digital dentistry was summarized.

後鼻漏를 主訴로 한 慢性 副鼻洞炎 患者의 治驗 1例

김창환,선영재,임웅경,김현기,Kim, Chang-hwan,Sun, Young-jae,Lim, Woong-kyoung,Kim, Hyun-gi 대한한방안이비인후피부과학회 2003 한방안이비인후피부과학회지 Vol.16 No.2

Paranasal sinusitis is a common disease in the otorhinolaryngology area. It is the change of inflammation at the mucous membrane which surrounds paranasal sinus. Chronic paranasal sinusitis is a chronic inflammation disease with purulent, mucous rhinorrhea, postnasal drip and cough. The attacked period continues above three months and it repeats exacerbation and remission. We diagnosed and treated an outpatient who complains postnasal drip of chronic paranasal drip of chronic paranasal sinusitis based on the Oriental medical theories and had good result.

남서태평양 라우분지 TA19-1 해산과 TA19-2 해산의 지자기 특성 연구

김창환,Kim, Chang Hwan 대한자원환경지질학회 2014 자원환경지질 Vol.47 No.4

한국해양과학기술원에서는 심해열수광상탐사를 위하여 2009년에 남서태평양 라우분지의 열수광상유망지역에 대하여 지구물리조사를 실시하였다. 그 중 TA19-1 해산과 TA19-2 해산에 대한 해상자력탐사 결과를 이용하여 이 해산들의 지자기 특성을 분석하였다. TA19-1 해산은 단순한 1개의 원추형 형태로 정상부는 함몰된 칼데라를 가진다. TA19-2 해산은 TA19-1 해산에 비해 규모가 크고 대규모 함몰대를 가진 칼데라가 나타나고, 칼데라 서쪽으로 정상부가 나타나며 능선들도 여러개 존재하는 형태로서 TA19-1 해산에 비해 복잡한 해저지형을 가지고 있다. TA19-1 해산의 자기이상은 정상부를 중심으로 북쪽에는 고이상대가 남쪽에는 저이상대가 나타나는 단순 쌍극자 이상 형태로 분포하고 있다. TA19-2 해산의 자기이상은 해산 북쪽 사면에 고이상대들이 위치하고 있고, 칼데라 서쪽에 위치한 정상부를 중심으로 고이상대가 나타나고 그 주변 및 칼데라 주위로 저이상대가 분포하며 TA19-1 해산에 비교하여 복잡한 형태의 자기이상을 나타낸다. 해저지형, 지자기 자료의 결과는 TA19-2 해산이 TA19-1 해산에 비해 복잡한 화산활동의 결과로 형성되었다는 것을 지시한다. 열수분출대의 가능성이 높은 저자화이상대들은 주로 해산의 정상부 및 칼데라와 칼데라 주변부에 주로 나타나는데 이는 단층 및 균열 등에 따른 열수 분출에 의한 암석 변질의 영향 등으로 판단되며, 정상부와 칼데라 내에 나타나는 높은 고자화대는 volcanic sill, intrusion 등 후기 화성활동과 연관성이 있을 것으로 사료된다. We conducted the geophysical survey of possible hydrothermal vent sites at 2009, in the Lau Basin, the south western Pacific and analyzed the magnetic characteristics of TA19-1 and TA19-2 seamounts. TA19-1 is a cone-shaped seamount with a caldera summit. TA19-2 seamount is bigger and shows more complicated topography than TA19-1 seamount. TA19-2 has a large caldera, a summit in the west side of the caldera and several crests. Simple dipole anomalies with a high over the north and a low over the south occur in TA19-1 seamount. High magnetic anomalies are located in the northern flank and the summit of TA19-2 seamount and low anomalies around the summit and the caldera. The results of bathymetry and magnetic data suggest that TA19-2 seamount might have more complicated magmatic process than TA19-1. Low magnetization zones are located over the summit, the calderas and the caldera rims. The magnetization lows indicate that submarine hydrothermal vents, along faults and fracture zones, could have caused an alteration of magnetic minerals. The magnetization highs over the summit and the calderas might have been related with later magmatisms like volcanic sills, intrusions.

AC 서보모터에 대한 견실한 외란억제 제어

김창환,Kim, Chang-Hwan 한국전자통신학회 2012 한국전자통신학회 논문지 Vol.7 No.4

In this paper, we propose a robust control scheme of AC servo motors to suppress disturbance torques effectively. The proposed controller consists of both a model based feed-forward controller and a stabilizing feedback controller. The feed-forward controller is designed such that the output of the nominal plant tracks perfectly the reference velocity command with desired dynamic characteristics. The feedback controller stabilizes the overall closed loop system. Furthermore, the feedback controller contains a free function that can be chosen arbitrarily. The free function can be designed so as to achieve both suppression of disturbances and robustness to model uncertainties. In order to illuminate the superior performance of the proposed control scheme to the conventional ones, we present some simulation results. 본 논문에서는 외란토크를 효과적으로 억제할 수 있는 AC 서보모터의 견실제어 방법을 제안한다. 제안된 제어기는 플랜트 모델에 기초한 피드포워드제어기와 안정화 피드백제어기로 구성된다. 피드포워드제어기는 공칭(nominal) 플랜트의 출력이 기준 속도명령을 정확히 추적하도록 설계되며 피드백제어기는 전체 폐루프시스템을 안정화시키는 역할을 한다. 피드백제어기는 임의로 선택될 수 있는 자유함수를 포함하는데 이 자유함수는 외란토크의 영향을 억제하고 제어기가 모델오차에 견실하게(robust) 동작되도록 선택될 수 있다. 컴퓨터 시뮬레이션을 통하여 제안된 제어방식이 기존의 제어방식들에 비해 우수한 제어성능을 가짐을 입증한다.

龍膽瀉肝湯加減方의 止血效果에 關한 實驗的 硏究

김창환,김경준,Kim, Chang-Hwan,Kim, Kyung-Jun 대한한방안이비인후피부과학회 2002 한방안이비인후피부과학회지 Vol.15 No.1

Based upon our laboratory experiments of Yongdamsagantang subtracted Bupleuri Radix and Yongdamsagantang subtracted Bupleuri Radix added Biotac Cacumen, Imperatae Rhizoma, Typhae Pollen on male rats to examine the medicines' hemostatic effect, we draw conclusions as follows: 1. Compared to the control group, Yongdamsagantang subtracted Bupleuri Radix and Yongdamsagantang subtracted Bupleuri Radix added Biotae Cacumen, Imperatae Rhizoma, Typhae Pollen increased the number of platelet counts meaningfully. 2. Compared to the control group, Yongdamsagantang subtracted Bupleuri Radix and Yongdamsagantang subtracted Bupleuri Radix added Biotae Cacumen, Imperatae Rhizoma, Typhae Pollen suppressed prothrombin time without any meaning. 3. Compared to the control group, Yongdamsagantang subtracted Bupleuri Radix and Yongdamsagantang subtracted Bupleuri Radix added Biotae Cacumen, Imperatae Rhizoma, Typhae Pollen, all of these medicines elevated the fibrinogen level, but only Yongdamsagantang subtracte Bupleuri Radix is recognized to raise the fibrinogen level meaningfully. 4. Compared to the control group, Yongdamsagantang subtracted Bupleuri Radix and Yongdamsagantang subtracted Bupleuri Radix added Biotae Cacumen. Imperatae Rhizoma, Typhae Pollen repressed partial thromboplastin time meaningfully. In conclusion, Yongdamsagantang subtracted Bupleuri Radix and Yongdamsagantang subtracted Bupleuri Radix added Biotae Cacumen, Imperatae Rhizoma, Typhae Pollen can be used for stopping blood effectively in terms of platelet count increase, prothrombin time control, fibrinogen level rise, and partial thromboplastin time suppression.

미사일 Fin 액츄에이터용 서보모터의 외란 토크 억제 제어

김창환,Kim, Chang-Hwan 대전대학교 군사연구원 2003 군사학연구 Vol.1 No.-

In this paper, we propose a generalized disturbance torque suppression control scheme of servo motors for missile fin actuators. Our controller consists of both a model based feed-forward controller and a stabilizing feedback controller. The feed-forward controller is designed such that the output of nominal plant tracks perfectly the reference position command with a desired dynamic characteristics. The feedback controller stabilizes the overall closed loop system. Furthermore, the feedback controller contains a free function that can be chosen arbitrary. The free function can be designed so as to achieve both the suppression of disturbances and the robustness to model uncertainties. In order to illuminate the superior performance of our control scheme to the conventional ones, we present some simulation results.

腦出血을 동반한 慢性 두드러기 患者의 治驗 1例

김창환,선영재,김현기,Kim, Chang-Hwan,Sun, Young-Jae,Kim, Hyun-Gi 대한한방안이비인후피부과학회 2002 한방안이비인후피부과학회지 Vol.15 No.1

Urticaria is classified as Eunjin in Oriental Medicine. The intrinsic causes include digestive system disorder, food poison, parasite, female reproductive health problem, nervous breakdown, and disorder of endocrine hormone. The extrinsic sources include all kinds of insect bites or stings, medications, pollen, dirt, and toxic smells. Some unknown sources also produce urticaria. The urticaria that lasts for more than six weeks, is categorized as chronic urticaria which is not very different from acute urticaria that occurs rapid but for a short period. The chronic urticaria may come every day, and its symptoms can even get worse at irregular or regular intervals. The cycle is hard to predict. It could be weeks or years. In clinical treatments, the syndromes of patient's chronic urticaria with cerebral hemorrhage have been analyzed and identified as follows: The diagnosis by asking the patient's case history showed that the root cause was retention of food resulting from dysfunction of the spleen and stomach. First, Pyeongwisan was dosed. From the syndrome differentiation with four diagnostic methods, we diagnosed the symptoms as Poong yoel (wind-heat). Then, Hyeongbangpaedocksangamibang was prescribed to get very effective results.

원격측정장치를 이용한 설치류의 생체신호 측정 및 분석

김창환,허경행,Kim, Chang-Hwan,Hur, Gyeong-Haeng 한국군사과학기술학회 2011 한국군사과학기술학회지 Vol.14 No.6

Telemetry techniques of rats have been used for assessing safety pharmacology of drugs and chemicals. Biological signals including blood pressure and heart rate measured under anesthesia were significantly different from those obtained under normal conditions. The stress of restraint in awake animals can also affect the accuracy of physiological evaluation. This paper details the surgery required to allow key cardiovascular parameters to be determined. The telemetric measurement of cardiovascular parameters such as blood pressure, heart rate, electrocardiograph(ECG) established. We carried out the continuous monitoring of cardiovascular parameters using the telemetry system in F344 rats. During the measurement, no significant changes were observed in the heart rate and blood pressure. ECG signals and body temperature were also constant during the measurement of biological signals. With the results of this study, we conclude that this telemetry system can be applied usefully for the assesment of biological parameters in the rats.

DIGITAL 전자교환기의 애스펙트

김창환,Kim, Chang-Hwan 한국전자정보통신산업진흥회 1981 電子振興 Vol.1 No.7