직접 변환 방식을 이용한 주파수 혼합기

임채성,김성우,최혁환,이명교,권태하,Lim Chae-sung,Kim Sung-woo,Choi Hyek-Hwan,Lee Myoung-kyo,Kwon Tae-ha 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.6

In this paper, Mixer using the direct-conversion method intended to use in front-end of a RF receiver is designed. The direct conversion Mixer is an alternative wireless receiver architecture to the well-established superheterodyne, particularly for high integration, low power, and low cost. It operates at 2.4GHz band, and is designed and simulated with a 0.35um CMOS technology and HSPICE simulator. Layout is implemented with a Mentor IC Station. The 2.4GHz CMOS Mixer employs a modified single-balanced Gilbert Cell with additional MOSFET in the output stages to improve IIP2, which is a standard of linearity in direct conversion receiver. Additional coversion-stages's transconductances are controlled by each MOSFET's physical properties. The HSPICE simulation results show that the 2.4GHz CMOS Mixer has voltage gam of 29dB, IIP2 of 63dBm, respectively. The Mixer also draws 3.5mA from a 3.3V supply. 본 연구에서는 RF 수신단에 적용할 수 있는 직접 변환 방식의 주파수 혼합기를 설계하였다. 직접 변환 방식의 주파수 혼합기는 기존의 헤테로다인 방식에 비해 고집적화가 가능하고 저전력 및 저가의 설계가 가능한 구조이다. 제안된 주파수 혼합기는 $0.35{\mu}m$ CMOS 공정을 이용한 2.4GHz대에서 동작하는 RF CMOS 주파수 혼합기로써, HSPICE를 이용하여 시뮬레이션 하였고, 레이아웃은 멘토사의 IC Station을 이용하여 수행하였다. 기본 single-balanced Gilbert Cell의 출력단에 추가 변환을 수행하였고, 각 변환단의 전달 컨덕턴스 값을 조절하여 결과적으로 출력단에 나타나는 2차 혼변조 성분이 differential 출력에 의해 충분히 개선되도록 하였다. 3.3V의 공급전압으로 29dB의 높은 전압이득을 얻었고 3.5mA의 전류소모가 발생하였다. 2차 혼변조 성분을 줄이기 위한 구조적인 변화를 통해 63dBm의 IIP2 값을 얻었다.

Paenibacillus donghaensis JH8에서 세포외 Xylanase의 특성

임채성,오용식,노동현,Lim, Chae-Sung,Oh, Yong-Sik,Roh, Dong-Hyun 한국미생물학회 2011 미생물학회지 Vol.47 No.1

Xylanase is a class of enzymes that hydrolyze the linear polysaccharide ${\beta}$-1,4-xylan into xylose. This enzyme is applied in the process of paper making and may be used for the process of biofuel production in the future. The Paenibacillus donghaensis JH8, isolated from Donghae deepsea sediment and reported as a novel bacterium, was known to degrade xylan and its xylanase was characterized in this study. The enzyme was maximally induced in the presence of 0.1% xylan. The production of xylanase was started at early logarithmic phase and reached about 55 miliunit at stationary phase of growth. The optimal temperature and pH of extracellular xylanase were found to be $40^{\circ}C$ and pH 6.0, respectively. The activity of xylanase was inhibited by the presence of $Ca^{2+}$, $Mn^{2+}$, $Fe^{2+}$, $Cu^{2+}$, $Al^{3+}$ or EDTA, and activated by $K^+$, $Ag^+$ or DTT. This xylanase was stable at $40^{\circ}C$ for 120 min, but lost almost their activity in 30 min at $60^{\circ}C$. Zymography analysis of concentrated culture supernatant revealed one major band at 42 kDa and two faint bands at 68 and 120 kDa. Xylanase는 선형복합다당인 ${\beta}$-1,4-xylan을 xylose로 가수분해하는 효소의 한 종류이며, 종이제조공정에 응용되고 미래에 바이오 연료의 생산에 사용 될 수 있다. 동해 심층 퇴적물로부터 신종세균으로 보고된 Paenibacillus donghaensis JH8은 배지중의 xylan을 분해한다고 알려져 있으며, 여기에서는 이 효소의 특성을 조사하였다. 효소는 0.1% xylan 존재에서 최고로 유도되었으며, xylanase의 생산은 초기 대수성장기에 효소를 생산하기 시작하여, 정지기에서 약 55 miliunit에 도달하였다. 세포외성 xylanase의 최적온도와 pH는 각각 $40^{\circ}C$와 pH 6.0이였다. Xylanase의 활성은 $Ca^{2+}$ 및 $Mn^{2+}$, $Fe^{2+}$, $Cu^{2+}$, $Al^{3+}$, EDTA의 존재에 의해 억제되었고, $K^+$, $Ag^+$, DTT에 의해 활성화되었다. 이 xylanase는 $40^{\circ}C$에서 120분간 활성을 유지하며 안정하였지만, $60^{\circ}C$에서는 30분에서 거의 모든 활성을 잃어버리는 특성을 보여주었다. 농축된 배양 상등액의 zymography 분석시 42 kDa의 주 밴드와 68과 120 kDa에 두 개의 아주 희미한 밴드를 나타내었다.

과학학습의 정의적 영역에서 사전-사후 통합 검사 설계의 타당화 연구: 과학영재를 대상으로

임채성,박형민,Lim, Chae-Seong,Park, Hyoung-Min 한국초등과학교육학회 2017 초등과학교육 Vol.36 No.3

In this study, the reliability and validity of the retrospective pre-post test were analyzed in order to solve the problem of traditional pre-post test including response shift bias. Samples of the study were 162 elementary school students who are studying at the S university gifted education center in Seoul. Before completion of the field trip, we conducted pre test of science-related attitudes. After completion of the field trip, respondents were asked to compare their responses of pre and post science-related attitudes to quantitatively analyze the commonalities and differences of the two tests. To find out more characteristics, qualitative data such as daily records and interview were also gathered and analyzed. The major results of the study are as follows. First, for the paired t-test, there was no statistically significant difference between separate pre-test scores and retrospective pre-test. There was a very high correlation between the separate pre-test scores and the retrospective pre-test. Second, there were significant differences in all seven sub-factors of science-related attitudes between the retrospective pre-test and the post-test. Third, the separate pre-test scores showed a slightly higher tendency than the retrospective pre-test scores. This suggests that the response shift bias appears when it is performed the separate pre-test in affective domain. As a result of the interview, it was found that the evaluation standards of separate pre-test did not match with those of post-test. Forth, internal consistency reliability of the retrospective pre-test was higher than that of the separate pre-test. However, there were significant differences in six factors of science-related attitudes excluding the 'social implications of science' between the separate pre-test and the post-test. Based on these results, the retrospective pre-post test design provides simplicity and convenience to both respondents and investigators, as it is done with one test. The retrospective pre-post test design can be regarded as a valid design for the self-report measurement of affective domain on a single experimental group.

말채나무 추출물의 ${\alpha}-amylase$ 저해 활성

임채성,이춘영,김용무,이위영,이해익,Lim, Chae-Sung,Li, Chun-Ying,Kim, Yong-Mu,Lee, Wi-Young,Rhee, Hae-Ik 한국응용생명화학회 2005 Applied Biological Chemistry (Appl Biol Chem) Vol.48 No.1

${\alpha}-Amylase$ 저해제는 소장에서 전분의 소화를 저해하여 포도당의 흡수를 지연시킴으로써 혈당 조절 목적으로 이용된다. 따라서 본 연구에서는 ${\alpha}-amylase$ 저해제를 탐색할 목적으로 국내 자생 목본류 약 1400여종의 70% ethanol 추출액을 대상으로 ${\alpha}-amylase$ 저해제 분포를 검색하였다. 수종의 목본류에서 ${\alpha}-amylase$ 저해제가 분포하고 있음이 확인되었으며, 그 중 활성이 비교적 높은 말채나무 기원의 저해제를 대상으로 연구를 진행하였다. 기원별 효소에 따른 저해 활성도를 살펴보면 salivary와 pancreatic ${\alpha}-amylase$, 미생물 기원의 ${\alpha}-glucosidase$에는 탁월한 저해 활성을 보인 반면 돼지 기원의 ${\alpha}-glucosidase$ 저해제에 대해서는 매우 낮은 저해 활성을 보였다. ${\alpha}-Amylase$와 ${\alpha}-glucosidase$의 kinetic을 분석하면 salivary와 pancreatic 두 효소에 모두 경쟁적 저해제로, 효모의 ${\alpha}-glucosidase$에는 비경쟁적과 반경쟁적의 혼합형 저해제로 나타났다. 또한 열과 산성에 대한 안정성을 확인한 결과 비교적 안정적인 것으로 나타났다. 본 추출물의 식이 섭취에 따른 혈당 강하 효과와 체중에 미치는 영향에서는 혈당과 체중 상승을 억제하는 효과가 확인되었고, mRNA수준에서 대퇴근 세포에 있어서 GLUT4의 발현이 증가됨을 확인하였다. ${\alpha}-Amylase$ inhibitor is used to control blood glucose level by inhibiting starch digestion in the small intestine and delaying the absorption of glucose. In this study, we investigated the effect of the ethanol extracts from more than 1400 species of plants against ${\alpha}-amylase$ with the aim of developing a new ${\alpha}-amylase$ inhibitor. In the results, Cornus walteri extracts showed the highest inhibition activity. The inhibitory effect of Cornus walteri extract on the carbohydrate hydrolysis enzymes has different sensitivities against ${\alpha}-amylase$ from salivary and pancreatin and against ${\alpha}-glucosidase$ from yeast and porcine small intestine. In the study of inhibition kinetics of ${\alpha}-amylase$ and ${\alpha}-glucosidase$, Cornus walteri extract showed competitive inhibition against salivary and pancreatin while showing the combination of uncompetitive and noncompetitive inhibition against ${\alpha}-glucosidase$. The Cornus walteri extract was stable at acidic and thermal conditions. As for the blood glucose and body weight levels of Cornus walteri extract, we confirmed anti-hyperglycemic and anti-obesity effects. Also, in the investigation of the mRNA lever, Cornus walteri extract upregulated the level of GLUT4 mRNA in the quadriceps muscle.

논문 : 만철(滿鐵)의 화북분리공작(華北分離工作)과 화북진출(華北進出): 철도운영을 중심으로

임채성 ( Chai Sung Lim ) 경제사학회 2006 經濟史學 Vol.40 No.-

본고는 화북철도를 둘러싼 중일양국의 대립과 그 귀추로서의 滿鐵의 華北進出과 華北交通의 設立過程을 검토함으로써, 중일전쟁이 중국 철도에 미친 영향을 살펴보고자 한다. 화북철도는 서구열강의 이권이 성립, 철도운영이 통일적이지 못하고 분할성을 띠었다. 이에 대해 국민당정부가 중앙통제를 강화하고 경영합리화를 추구하였으나, 근본적인 개혁에는 이르지 못했다. 이에 대항하여 滿鐵은 華北分離工作을 전개, 화북에 종합개발회사로서 진출하고자 하였다. 중일전쟁이 발발하자 만철은 北支事務局을 설치하고 점령철도를 운영하게 되었다. 이를 통해 설립된 華北交通(株)은 역설적이기는 하나 중국측이 추구한 철도운영의 통일성을 실현한 것이었다. 즉, 중일전쟁의 발발은 특정 운영시스템이 확정되지 않고 분할적으로 운영되던 중국철도가 만철을 모델로 한 일본적 운영시스템으로 개편되는 계기가 되었다. European powers controlled different parts of northern China, which fragmented the northern Chinese railway system. The Kuomintang government’s attempts to rationalize railway management by introducing central control resulted in failure. Japan set up the South Manchurian Railway Company (SMR) to place northern China under its control. With the outbreak of the Sino-Japanese War, SMR began to manage the northern Chinese railways by setting up the North China Transportation Company. One important consequence of the Japanese occupation was the emergence of a railway network in northern China organized and unified in the framework of the Japanese system.

뇌 기반 진화적 과학 교수학습 모형을 적용한 초등학교 학생의 자유 탐구 활동에서 과학 태도와 흥미 주제 영역 분석

임채성 ( Chae Seong Lim ),김재영 ( Jae Young Kim ),백자연 ( Ja Yeon Baek ) 한국초등과학교육학회 2012 초등과학교육 Vol.31 No.4

Interest is acknowledged to be a critical motivational variable that influences learning and achievement. The purpose of this study was to investigate the interest of the elementary students when free inquiry activities were performed through a brain-based evolutionary scientific teaching and learning model. For this study, 106 fifth grade students were chosen and performed individually free inquiry activities. The results of this study were as follows: First, after free inquiry activities, as to free inquiry science related attitude, a statistically significant difference was not observed. But they came to have positive feelings about the free inquiry. Especially students marked higher mean score in openness showed consistency in sub-areas of free inquiry science related attitude. Second, students had interests in various fields, especially they had many interests in area of biology. They chose inquiry subjects that seems to be easily accessible from surrounding and as an important criterion of free inquiry they thought the possibility that they could successfully perform it. And students who belong to the high level in the science related attitudes and academic achievement diversified more topics. Third, most of students failed to further their topics. However, the students who specifically and clearly extended their topics suggested appropriate variables in their topics. On the other hand, students who couldn`t elaborate their topics were also failed to suggest further topics and their performance of inquiry was more incomplete. In conclusion, the experiences of success in free inquiry make the science attitude of students more positive and help them extend their inquiry. These results have fundamental implications for the authentic science inquiry in the elementary schools and for the further research.

철도원과 신체

임채성(Lim, Chaisung) 고려대학교 아세아문제연구소 2012 亞細亞硏究 Vol.55 No.3

This paper analyzed the change of labor hygiene system of Japanese National Railways(JNR) and the measure of the JNR authorities taken to that. The efficiency of transport was pursued by JNR, because the enormous transport demand occurred during World War I. However, since the turnover rate of railways workers increased, the decline of the average age and service period happened. Therefore it brought about the increase of injury rate. Besides, Spanish influenza spread throughout the country. The large-scale and delicate medical system and the social insurance-like mutual aid association system were established to cope with these situations. Many workers were able to receive a modern medical care service by those systems. Medical coverage expanded from staff patients of diseases and injuries sustained while on duty to staff patients of diseases and injuries sustained while off duty, finally to staffs" families. Meanwhile, railroad workers" bodies were not in the state that they had no disease but in the state that even if they were taken of a disease, they received the precise medical treatment and didn"t come to death. That is, their bodies became management items to be expected to prove the utility value as the labor. As a result, in spite of the increase of mobility rate from 1920s to the first half of 1930s, the fact that the accident rate and death rate decreased was verified. It"s readable that the health management of JNR authorities to a body of JNR staff was effective in this contradiction between morbidity rate and death rate.

다중지능에 기초한 과학 프로젝트 활동이 초등학교 아동의 문제해결 행동에 미치는 영향

임채성(Chae Seong Lim),왕경순(Kyung Soon Wang) 한국초등과학교육학회 2000 초등과학교육 Vol.19 No.1

This study examined the influences of science project activities based on multiple intelligences on problem solving behaviors of elementary school children. Specifically, the influences of the project activities on the problem solving skills and propensities of the children were investigated. Forty-four fifth graders were selected for the study. They performed the projects and made their products of it during five months on the units of $quot;Weather$quot; and $quot;Our Body$quot;. Criteria for assessment of problem solving abilities were determined. The patterns reflected in products of the project activities were examined, then the observation of the subjects` problem solving behaviors and the interviews were performed based on the criteria. The results were analyzed through both of qualitative and quantitative approaches. In these analyses, the implementation of the science projects was found to contribute to the improvement in all sub-factors of problem solving, specially, skills associated with the propensities of problem identification and of the collection, analysis, and synthesis of data significantly increased

전후 만철의 접수와 중국 동북철도의 재편

임채성(Lim, Chaisung) 연세대학교 국학연구원 2016 동방학지 Vol.174 No.-

본고의 목적은 구 만철, 즉 중국동북철도를 대상으로 전후 만철이 어떻게 접수되어, 소련점령과 국공내전 가운데 재편되었는가를 밝힘으로써, 그것이 갖는 전후사적 의미를 고찰하는 것이다. 패전시 만철은 소련군에 접수됨에 따라 중국 인의 자주적이고 정상적인 철도운영이 즉각 실현되지 못하고, 소련군의 만주점령과 만주산업 시설의 반출을 겪게 되었다. 접수과정 또한 극히 체계적이지 못하고, 각각의 지역에서 전황의 전개와 중국인의 대응방식에 의해 결정된 바가 컸 다. 전체적으로 중국인의 기술 및 관리능력은 낮았기 때문에, 소련군의 점령에서 국민당의 통치를 거쳐 공산당의 운영관리에 이르기까지 동북 철도의 운영을 위해서는 일본인의 기술과 관리 능력은 필수적이었다. 소련군의 철수와 더불어 국민정부가 진출하 였고, 1946년에서 47년에 걸쳐 동북행원을 중심 으로 철도운영을 하기 시작하여 일정한 성과를 거두었다. 그러나 주변부에 확실한 기반을 구축한 중공측이 반격에 나서자, 국부측의 철도망은 축소되었고, 결국 철수할 수밖에 없었다. 이에, 내전의 본격화에 대비하여 철도관리체제를 정비한 중공측은 군사작전에 철도를 우선적으로 동원하여 승전의 가능성을 잡았다. 바로 동북철도는 중공측에게 있어 만주라는 보급기지로부터 군수품을 공급하는 보급로였다. 내전승리 이후 동북철도의 사회주의적 철도 개조가 시작되었 다. 소련 전문가가 초빙되어, 일본인 유용자(留 用者)를 대신하여 사회주의 철도운영방식을 광범위하게 보급하였고 기술적 공백을 메워갔다. 이와 같이 전전 일본제국권 가운데 가장 높은 수준을 보인 구 만철(중국동북철도)는 전후 에도 ‘신형철로’가 전중국에 전파되는 기술적 ‘원천’이 되었던 것이다. This paper set out to examine the ways the South Manchuria Railway (SMR), i.e. the Northeast Railway of China, was requisitioned at the end of WW Ⅱ and was reorganized during the occupation of the Soviet Red Army and the Chinese Civil War, as well as to consider their postwar significance. As the SMR was requisitioned by the Soviet Red Army, China could not manage an independent and normal railroad service immediately, instead experiencing the Soviet occupation and the illegal transfer of Manchurian industrial facilities to the Soviet Union. However, due to the low level of Chinese technical and management ability, the Japanese were needed for the operation of the Northeast Railway of China from the occupation of the Soviet Red Army to the rule of the Kuomintang and the victory of the Communist Party. With the withdrawal of the Soviet Army, the Kuomintang Government began to manage railroads and achieved some results from 1946 to 1947. After the Communist Chinese Army launched a counterattack, there was no choice but to reduce and finally withdraw the railway network of the Kuomintang. The Communist Chinese Army organized the railroad management system as a supply route and grabbed at a chance for a war victory. Indeed, the Northeast Railway of China was the logistic network that supported the conduct of operations initiated by the Communist Chinese Army in the south of Shanhaiguan. The Northeast Railway of China, which had the highest level of technology among all prewar Japanese railways, was used as the “source” for a new type of railways after the liberation.

쌀과 철도 그리고 식민지화 -식민지조선의 철도운영과 미곡경제

임채성 ( Chai Sung Lim ) 쌀·삶문명연구원 2008 쌀삶문명 연구 Vol.1 No.-

식민지 철도망 정비는 전통적인 상품인 미곡의 생산, 유통에 커다란 영향을 미쳤다. 즉, 철도와 더불어 일본인 진출이 이루어졌을 뿐만 아니라 이를 통해 개량품종 등 근대적인 농업기술이 전파되어 미곡생산이 증가하였다. 특히, 산미증식계획이 실현됨에 따라, 철도를 기반으로 미곡의 수이출이 이루어졌음을 계량분석을 통해 확인할 수 있었다. 즉, 철도에 의한 수송 신속화와 저렴화는 조선내 증산된 양보다 많은 미곡의 일본 이출을 가능하게 하였던 것이다. 그 결과, 조선의 미곡생산은 일본의 토쿄, 나고야, 오오사카 등의 미곡시장과 연결될 수 있었으며, 이를 통해 식민지 지소작제도가 심화되게 되었다. 요컨대, 식민지조선에서의 철도는 정치군사적인 목적을 중심으로 하여 건설되었지만, 이와 동시에 미곡 사례에서 볼 수 있듯이 조선경제의 제국내 편입을 보장하는 사회기반이 되었던 것이다. Formation of a colonial railway system in Korea had a critical influence on production and circulation of the rice which were traditional goods. Japanese moved to Korea with construction of Korean National Railroad and modern agricultural technology like breeding was transmitted. In particular, it was analyzed in regression models that rice was exported to Japan based on railroads, as The Government-General of Korea executed Rice Production Increase Plan of Korea. That is, the rapidity and low cost of railroad transport enabled to export more rice than the amount which increased in Korea. As a result, the rice production of Korea was connected to the Japanese rice market in Tokyo, Nagoya and Osaka and this reinforced colonial landlord system of rice agriculture. Thus Colonial Korean railroad system was constructed for the purpose of political military occupation, but it also became the socio-economic infrastructure that enabled integration of Korean economy to Japanese empire.