• Title/Summary/Keyword: low-loss

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Development of DAP(Dose Area Product) for Radiation Evaluation of Medical and Industrial X-ray generator (의료 및 산업용 X-선 발생장치의 선량평가를 위한 면적선량계(DAP) 개발)

  • Kwak, Dong-Hoon;Lee, Sang-Heon;Lee, Seung-Ho
    • Journal of IKEEE
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    • v.22 no.2
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    • pp.495-498
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    • 2018
  • In this paper, we propose an DAP system for dose evaluation of medical and industrial X-ray generator. Based on the DAP measurement technique using the Ion-Chamber, the proposed system can clearly measure the exposure radiation dose generated by the diagnostic X-ray apparatus. The hardware part of the DAP measures the amount of charge in the air that is captured by an X-ray. The high-speed processing algorithm part for cumulative radiation dose measurement through microcurrent measures the amount of charge captured by X-ray at a low implementation cost (power) with no input loss. The wired/wireless transmission/reception protocol part synchronized with the operation of the X-ray generator improves communication speed. The PC-based control program part for interlocking and aging measures the amount of X-ray generated in real time and enables measurement graphs and numerical value monitoring through PC GUI. As a result of evaluating the performance of the proposed system in an accredited testing laboratory, the measured values using DAP increased linearly in each energy band (30, 60, 100, 150 kV). In addition, since the standard deviation of the measured value at the point of 4 division was ${\pm}1.25%$, it was confirmed that the DAP showed uniform measurements regardless of location. It was confirmed that the normal operation was not less than ${\pm}4.2%$ of the international standard.

Effects of the Doping Concentration of the Floating Gate on the Erase Characteristics of the Flash EEPROM's (Flash EEPROM에서 부유게이트의 도핑 농도가 소거 특성에 미치는 영향)

  • Lee, Jae-Ho;Shin, Bong-Jo;Park, Keun-Hyung;Lee, Jae-Bong
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.11
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    • pp.56-62
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    • 1999
  • All the cells on the whole memory array or a block of the memory array in the Flash EEPROM's are erased at the same time using Fowler-Nordheim (FN) tunneling. some of the cels are often overerased since the tunneling is not a self-limited process. In this paper, the optimum doping concentration of the floating gate solve the overerase problem has been studied. For these studies, N-type MOSFETs and MOS capacitors with various doping concentrations of the gate polysilicon have been fabricated and their electrical characteristics have been measured and analyzed. As the results of the experiment, it has been found that the overerase problem can be prevented if the doping concentration of the floating gate is low enough (i.e. below $1.3{\times}10^{18}/cm^3$). It is because the potential difference between the floating gate and the source is lowered due to the formation of the depletion layer in the floating gate and thus the erasing operation stops by itself after most of the electrons stored in the floating gate are extracted. On the other hand, the uniformity of the Vt and the gm has been significantly poor if the coping concentration of the floating, gate is too much lowered (i.e. below $1.3{\times}10^{17}/cm^3$), which is believed to be due to nonuniform loss of the dopants from the nonuniform segregation in the floating gate. Consequently, the optimum doping concentration of the floating gate to suppress the overerase problem and get the uniform Vt and has been found to range from $1.3{\times}10^{17}/cm^3$ to $1.3{\times}10^{18}/cm^3$ in the Flash EEPROM.

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MAXILLARY MOLAR DISTALIZATION WITH THE BONE-SUPPORTED PENDULUM (Bone-supported pendulum을 이용한 상악대구치 원심이동)

  • Jang, Yong-Gul;Park, Ho-Won;Lee, Ju-Hyun;Seo, Hyun-Woo
    • Journal of the korean academy of Pediatric Dentistry
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    • v.36 no.3
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    • pp.464-474
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    • 2009
  • To distalize the maxillary molars, the traditional techniques such as extra-oral traction, Wilson distalizing arches, removable spring appliances and Schwarz plate-type appliances have been used. But, these need considerable patient cooperation. For minimal patient compliance, many practitioners use the pendulum appliances. Several clinical studies demonstrated pendulum is effective molar distalization appliance in the growing patient(using the premolars and the palate as anchorage). But unfortunately, maxillary anterior teeth also shift mesially as the molar moves distally. As a result anchorage loss is occurred. To overcome these disadvantages, we used bone-supported pendulum, combined the conventional pendulum with Skeletal Anchorage System(SAS). The miniscrew was implanted in the anterior paramedian region of the median palatal suture, which has comparatively sufficient bone thickness and is low risk to damage on the dental follicles. We report three cases, using bone-supported pendulum for the maxillary molar distalization in children. After treatment, we find out anchorage stability, minimal unfavorable anterior tooth movement and sufficient molar distalization.

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The Life of women living in South-Korean and North-Korean in the family life (가정생활 속의 남북한 여성의 삶)

  • 문숙재
    • Journal of the Korean Home Economics Association
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    • v.35 no.2
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    • pp.321-331
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    • 1997
  • This paper begins with the question, 'What is the life of women living in the South Korea and North Korea?'. The question is quite significant but not known well. In fact, there have been great differences between South and North-Korean societies since the partition of the Korean Peninsula. In this sense, the family life in women living in south and North Korea can not be exceptional. The task on which women in South and North Korea are currently facing is not only to overcome heterogeneity in such areas as politics, economics, and socio-cultural systems, but also to recover homogeneity we had shared for a long history before the partition. The difference in the ideology makes a difference to decide on a policy on the household work. It comes out of the socialization method of household work. In North-Korea, the collectivization of household work get a lot of accomplished in South-Korea. This made differences in the domesticity between South-Korea and North-Korea. So, the purpose of this study is to compare the domesticity in North-Korea and South-Korea to prepare for unification of North and South-Korea. To compare the family life in South-Korea and North-Korea, this study adjusts the focus of the socialization of household work. Ther is a great difference in the ideology between the two political systems. In the North korean society, in order to help women manage their 'the double role' for home and workshop, the socialization of housework strategy has been strongly recommended. But socialization of housework strategy has been proven to have a number of problems: the loss of family individuality, inhumanization of family, family's scattering, and a low quality. Therefore, this strategy has not been used widely. But, the collectivization of housework has been used widely. There are three types in the socialization of housework: the commercialism of housework(가사노동의 영리화), the collectivization of housework(가사노동의 집단화), and the public of housework(가사노동의 공공화). Otherwise, the commercialism of housework has been used widely in south korean society. Yet it is very far from North-Korean life due to a shortage of goods. As a result, the different idelogies result the different family life. The different family life is proven to the different socialization of housework. This is very significant. If the unification of North and South Korea is realized, the socialiation of housework can be used a strategies to overcome the differences of the South and the North.

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A Study on the Causes of Hwa-byung and Practical Use of Psychodrama for Treatment of Hwa-byung : (focused on middle-aged women) (화병(火病)의 원인과 치료를 위한 사이코드라마의 활용 방안 연구 : 중년여성을 중심으로)

  • Byun, Sang-Hae;Eo, Ji-Sung
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.4 no.2
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    • pp.1-19
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    • 2009
  • American Psychiatric Association defined hwa-byung as a unique mental illness of Korea, a kind of anger syndrome. This illness caused by the Korean culture is more often found on women than men, especially middle-aged women. The cause of hwa-byung mainly depends on the traditional family structure of Korea formed by Confucianism. Other causes that many middle-aged women suffer from hwa-byung are that their low education level originated in their wrong-recognized position in society and poverty in the past makes them not to be able to control their minds effectively(social psychological factor), and that they get stressed and depressed because of loss of their position in the family after their children leave home and the menopause which hurts their feminine beauty (physiological factor). So, this program aims at letting them to; 1) experience catharsis of the negative feelings which causes hwa-byung by expressing in psychodrama, 2) ease the symptoms of hwa-byung by relaxing their mind, 3) understand themselves through sharing their feelings and thinking at the group level, 4) acquire the opportunities to stabilize and expand their role in their real lives through the role playing.

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The Effect of Information Security Breach and Security Investment Announcement on the Market Value of Korean Firms (정보보안 사고와 사고방지 관련 투자가 기업가치에 미치는 영향)

  • Kwon, Young-Ok;Kim, Byung-Do
    • Information Systems Review
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    • v.9 no.1
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    • pp.105-120
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    • 2007
  • With the fast development of the Internet and the increasing dependence on information infrastructures, companies are faced with various information security threats such as information leakages, modifications, and information breaches. South Korea is one of the leading countries in the Internet usage, but is ranked relatively low when it comes to information security. In fact, many Korean firms have suffered financial losses and damaged corporate images from the information security breaches. However, because of the difficulties in quantifying the costs of the information security breaches, Korean companies tend to delay their investment decisions on information security. The purpose of this study is to measure the cost of information security breach and the economic value of security investment using the event study methodology. Our results show that the announcement of an information security breach negatively influenced the market value of the corresponding company. The effect was statistically significant at the significance level of p=0.05. The breached companies lose, on average, 0.86% of their market values on the day of the announcement - an average loss in market capitalization of $55 million. On the other hand, the investment on information security had no effect on the stock price or the market value of the firm.

Effect of Singeing Time on Physico-Chemical Characteristics of Duck Meat (오리육의 화염 처리 수준에 따른 이화학적 특성)

  • Chae, H.S.;Yoo, Y.M.;Ahn, C.N.;Jeong, S.G.;Ham, J.S.;Lee, J.M.;Singh, N.K.
    • Korean Journal of Poultry Science
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    • v.33 no.4
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    • pp.273-281
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    • 2006
  • Singeing has always been equated with meat color alteration through lipid oxidation and microbial population. Singeing method has always been employed far removing duck feathers, however, the effect of singeing on storage characteristic of duck meat has not been investigated extensively. The study was therefore, designed to Investigate the effect of singeing on duck meat during storage extensively. For the purpose, study was categorized into three groups namely A, B, and C, representing 0, 50 and 70 seconds of singeing time. Singeing was performed on 100 birds in each group, however, only 20 singed birds from each treatment groups were further selected to analyse them subsequently during storage. Analysis revealed that with 70 seconds singeing time drip loss was significantly (p<0.05) higher at $6mgf/cm^2$ compared to 50 seconds of singeing. With 70 seconds treatment breast meat apparently appeared black, where as with 50 seconds treatment no change was observed. Breast showed low redness with more duration of treatment compared to less treatment duration. Yellowness increased, springiness declined and no change was observed in cohesiveness and chewiness with high treatment time. There was increase in the TBARS and VBN, freshness did not change for first 5 days, however, K values started to increase later on indicated decline in freshness. Conclusively, it was inferred from the study that 50 seconds singeing does not make much alternation in the quantitative traits and at the same time maintains the microbial level under permissible limit.

Studies on Ancylostomiasis II. Clinical Symptomatology, Effects of Drugs, especially of Iron Compounds, with Relation to the Severity of Artificial Infection (구충증(鉤蟲症)에 관(關)한 연구(硏究) 제2편(第2編) 감염경중(感染輕重)에 따른 구충증(鉤蟲症)의 임상증상(臨床症狀), 빈혈상(貧血像) 및 약물(藥物) 특(特)히 철제제(鐵製劑)의 효과(效果))

  • Lee, Mun-Ho;Kim, Dong-Jip;Lee, Jang-Kyu;Seo, Byong-Sul
    • The Korean Journal of Nuclear Medicine
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    • v.1 no.2
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    • pp.41-59
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    • 1967
  • This study was aimed; firstly to observe various clinical symptomatology with reiation to the number of Ancylostoma duodenale larvae orally given to the human beings, secondly to evaluate the effects of some drugs like steroid hormones, antihistaminic3 and antitussives, and, thirdly to study the influences of some iron compounds in prevention and treatment of anemia of such origin. Ten healthy volunteers free from the previous history of hookworm infection were divided into 4 groups, to whom various numbers of actively moving filariform Ancylostoma duodenale larvae were orally given; 500 to 4 cases, 250 to 3 cases and 100 to 3 cases. Following were the results: 1. Clinical symptomatology 1. The most frequently encountered symptoms and signs were general malaise, cough and hoar seness. The tracheal itching and pain low back pain, arthralgia, sputum and salivation, acid belching, loss of appetite, abdominal pain and vomiting were also noted. 2. If the larger number of the larvae was given, the clinical symtomatology was more severe. 3. Prednisolone medication caused some improvement of such symptomatology, while the antihistaminics and antitussives like codeine or ephedrine were ineffective. 4. In volunteers whose nutritional conditions were rather poor appeared to show more severe symptomatology. 2. Effects of iron compounds 1. The oral administration of ferrous fumarate induced a slight increase of serum iron levels in the initial stage of the infection, then a decrease from $15{\sim}20$ days later and a recovery after 2 months. 2. The intravenous administration of saccharated ferric oxide induced a steady upkeep of the serum iron levels. 3. The hemoglobin contents also showed the upkeeps after either the oral or intravenous administration of the iron compounds. 4. The iron compounds, therefore, are considered to have the preventive as well as the therapeutic effects on hookworm anemia, which may strongly suggest that hookworm anemia is essentially the iron deficiency type. 3. Hematological changes 1. The severity of hookworm anemia generally correlated with the number of larvae given. 2. The moderate leucocytosis was observed in all cases regardless of the number of larvae given, which reached to a peak in $25{\sim}35$ days. 3. Eosinophilia was observed in all cases, but was more severe in cases given larger number of larvae, which was slightly less evident after the medication of prednisolone. 4. Red cell survival time The red cell survival time determined by $^{51}Cr$ was generally in the normal ranges except for the severe anemia patients.

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Theoretical Study on Fuel Savings of Marine Diesel Engine by Exhaust-Gas Heat-Recovery System of Combined Cycle (복합 사이클의 배기가스 열회수 시스템에 의한 선박용 디젤엔진의 연료 절약에 관한 이론적 연구)

  • Choi, Byung Chul;Kim, Young Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.2
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    • pp.171-179
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    • 2013
  • The thermodynamic characteristics of a combined cycle applied with a topping cycle such as a trilateral cycle at relatively high temperatures and a bottoming cycle such as an organic Rankine cycle at relatively low temperatures have been theoretically investigated. This is an electric generation system used to recover the waste heat of the exhaust gas from a diesel engine used for the propulsion of a large ship. As a result, when the boundary temperature between the topping and the bottoming cycles increased, the system efficiencies of energy and exergy were simultaneously maximized because the total exergy destruction rate (${\sum}\dot{E}_d$) and exergy loss ($\dot{E}_{out2}$) decreased, respectively. In the case of a marine diesel engine, the waste heat recovery electric generation system can be utilized for additional propulsion power, and the propulsion efficiency was found to be improved by an average of 9.17 % according to the engine load variation, as compared to the case with only the base engine. In this case, the specific fuel consumption and specific $CO_2$ emission of the diesel engine were reduced by an average of 8.4% and 8.37%, respectively.

Quality Changes and Shelf-life of Grill Sausages Re-pasteurized after Packaging during Chilled Storage (이차살균한 그릴소시지의 냉장 저장 중 품질 변화와 저장 수명)

  • 이근택;최원선;우문제;이정표
    • Food Science of Animal Resources
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    • v.24 no.1
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    • pp.29-36
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    • 2004
  • Changes in quality characteristics and shelf-life of two types of grill sausage manufactured by using pork hind leg and re-pasteurized after packaging were investigated during storage at 5$^{\circ}C$ and 10$^{\circ}C$ up to 30 days. The total aerobic plate counts(APC) of N rnberger style grill sausage(NGS) and vegetable added grill sausage(VGS) were initially 3.08 and 3.57 log$\sub$10/CFU/$\textrm{cm}^2$, respectively, and gradually increased during storage time. After 30 days, the APC of NGS stored at 5$^{\circ}C$ and 10$^{\circ}C$ maintained relatively low at the levels of 5.32 and 6.58 log$\sub$10/CFU/$\textrm{cm}^2$, respectively. However, the APC of VGS exceeded the level of 8 log$\sub$10/CFU/$\textrm{cm}^2$ after 30 days at 5$^{\circ}C$ and after 20 days at 10$^{\circ}C$. pH was decreased with storage period, however it tended to increase after 30 days. The values of TBA and VBN for both sausages tended to increase with storage time, and this trend was pronounced at 5$^{\circ}C$ rather than at 10$^{\circ}C$. The purge loss was apparently increased in the VGS compared to the NGS sample as the storage period extended. According to the sensory evaluation, the marketing values of grill sausages stored at 5$^{\circ}C$ and 10$^{\circ}C$ were maintained until day 20 for NGS and day 14 for VGS, respectively.