• 전자공학회논문지D
• /
• 제34D권9호
• /
• pp.56-63
• /
• 1997

There generally exists a large variation in the thereshold voltages of the flash EEPROM cells after they are erased by using th fowler-nordheim tunneling, thereby getting some cells to be overeased. If the overerased cells are programmed with the conventional one-step programming scheme where an 12-13V pulse with the duration of 100.mu.S is applie don the control gate for the programming, they can suffer from the significant degradation of the reliability of the gate oxide. A two-step programming schem, where an 8/12 V pulse with a duration of 50.mu.S for each voltage is applied on the control gate for the programming, has been studied to solve the problem. The experimental results hav eshown that there is little difference in the programming characteristics between those two schemes, whereas the degradation of the gate oxide due to the programming can be significantly reduced with the two-step programming scheme compared to that with the one-step programming scheme. This is possibly because the positive charge stored in the floating gate of the overerased cells is compensate dwith the electrons injected into the floating gate while the 8V pulse is applied on the control gate, which leaves the overerased cells in the normally erased state after the duration of the 8V pulse.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2005년도 연구개발 발표회 논문집
• /
• pp.158-165
• /
• 2005

KOGAS(Korea Gas Corporation) has about a hundred of local stations to supply natural gas to the city gas companies and the power stations. As some severe flow fluctuation phenomena are observed in several governor stations, the investigation about the reasons and factors which are relating to flow fluctuation has been started. Some field surveys hav been carried out and experimental studies have been performed to find the fluctuation mechanism. As a result, it is found that the flow fluctuation is related with the length of straight pipe in front of the meter, the size of the header pipe and the variation of demand at the city gas company and the power station. Furthermore. it is also proved that both the length of the transmitter cable and the status of the coating of signal transmission cable do not affect flow fluctuation, but the measurement range of the differential pressure transmitter influences flow fluctuation. On the other hand, as the averaging the flow fluctuation is converged to less than 0.1 % in almost all of the cases, it is concluded that the quantity of flow fluctuation do not relates to metering accuracy directly.

• 한국가정과교육학회지
• /
• 제3권1호
• /
• pp.163-177
• /
• 1991

The consciousness and food preference of Korean foods by high school girls in Kwangju city and Chonnam area was surveryed by questionnaire. The results were as follows； 1. Although the cooking methods of Korean foods were scientific(63.8%), they have to be improved because of complication and difficulty. The point of improvement in the urban area was cooing method but that in the rural area was nutrition and hygiene 2. The motives of hav8ing interest in korean tradition foods were through home life and school education, mass communication and etc. As the subjects live in more urban area and have high income level, they were affected by school education and mass communication. 3. They are used to eat both traditional and nontraditional foods on the korean festive days and annual functions. There is tendency to decrease the use of traditional foods gradually because of complicated their cooking methods and long cooking time. 4. Most household responded that Korean traditional food are must to succession development (52.9%), because of succeed to korean diet culture and suit one’s taste. The more pride of traditional food are kimchi, rice cake, sweet rice drink, persimmon punch, sweet waxy rice cooked potherbs. 5. The preference about the korean foods were high in this order of chopsuey, mandu, laver, shikhae, cooked waxy rice. And they were low in salted anchovies salted yellow convina liver cheon, oyster cheon.

• Journal of Biosystems Engineering
• /
• 제4권1호
• /
• pp.67-74
• /
• 1979

This survey was carried out to grasp the actual condition of a power tiller utilization . Now, the power tiller has become the leading machinery in the field of agriculture throughout the country . Two hundred farm houses, located in the provincial districts of Kimcheon and kum0rung, hav etaken part in the survey from October 1, 1976 to September 30, 1977. The results are summarized as follows . 1. The average size of cultivated land of a farm household in the districts surveyed was 1.77ha which was bigger than that of whole country. And the average age of power tiller drivers was analyzed in which only 105 of total drivers was on their 30's. 2. Distribution of a power tiller utilization was appeared to be 34.4% for transporting , 24% for tilling , 23% for pumping , 11.5% for threshing and 6.6% for spraying. 3. Frequency of a power tiller utilization was high during the month of June, July and October while it was low during February and December . 4. Distribution of repairing cost was 8.5% for trailer, 7.1% for throttle lever and 6.7% for casket, respectively. The annual cost for repairing was 5,290 won.5. The annual cost for using a power tiller was composed of 51.5% of fixed cost and 48.5% of operating cost. 6. Economic analysis showed that it was not economically practical for individual ownership of a power tiller on the farm surveyed. Therefore, custom operation and joint ownership by a few farmers were recommended.

• 고문화
• /
• 57호
• /
• pp.129-144
• /
• 2001

우리나라의 고와중에서 특히 막새기와에는 제작당시에 유행 또는 선호되었던 문양이 시문되어 있어 일찍부터 기와연구의 지름길로 인식되면서 주된 고갈 대상이 되어 왔다. 이 중에서 통일신라시대의 암수막새들은 그 문양과 종류의 다양함에서 다른 나라의 것과는 비교하기 어려울 정도이다. 본고에서는 막새문양면에 시문된 무늬는 같은데, 주연부 높이$\cdot$접합기법$\cdot$상하주연의 유무 등에서 차이를 드러낸 3종 8점에 대한 고찰을 통하여 다음과 같은 결론에 도발하게 되었다. 1. 고찰한 3종류의 기와들은 세부형태의 큰 차이에도 불구하고 종류별로 같은 시기에 제작되었을 것으로 본다. 2. 기와제작기법 그 자체가 편년의 기준이 될 수 있는 시간적 범위는 어떤 기법이 처음 도입$\cdot$발생되었을 무렵에 그 기법에 의하여 제작되었던 유물에만 적용가능하다고 생각된다. 3. 이러한 고찰 결과에 따라 고와편년에는 그것이 출토된 층위, 공반유물(특히 토기) 비교 등 외에도 다양한 방법에 의한 접근이 필요함을 재강조하고자 한다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
• /
• pp.100-105
• /
• 1995

$Na_2O$함량 20, 52, 30 mol% 변화를 준 $Na_2O$-CaO-$Al_2O_3$-$B_2O_3$-$SiO_2$계 유리를 제조하여 $AgNO_3$용융염에 각각 0, 24, 36, 48 시간동안 이온교환처리를 행한후 시편의 전기적 특성을 분석하였다. 이온 교환처리된 유리의 저항값과 활성화에너지값이 이온교환처리 되지 않은 모유리보다 낮았다. $Na_2O$의 함량이 증가할수록, 이온교환시간이 증가할수록 전기전도도는 증강하였다. 본 실험에서는 $Na_2O$ 함량 30 mol%의 유리를 48시간 이온교환시킨후의 시료의 전기전도도가 제일 좋았으면 $200^{\circ}C$ 에서의 전기전도도는 $1.78\times$$10^{-4}$S/cm이었다.

• Journal of Periodontal and Implant Science
• /
• 제37권3호
• /
• pp.625-636
• /
• 2007

Marginal tissue recession makes problems like esthetics, root caries, hypersensitivity and plaque accumulation. Request for root coverage is higer than ever, especially esthetic problems involved. So techniques for root coverage hav been developed. There are some kinds of surgical techniques using soft tissue for root coverage. For example, free gingival graft, kinds of pedicle flap, subepithelial connective tissue graft(SCTG), and so on. Subepithelial connective tissue graft has many advantage for root coverage, that is less pain on donor site, good blood supply for graft, and more esthetic result. For this reaseon, this case report was performed to evaluate the effect of root coverage using subepithelial connective tissue graft. Three patients has Miller's class I marginal tissue recession and one patients has Miller's class III marginal tissue recession. The following period is 36.5 month on average. The results are as follows: 1. Root coverage of 100% was obtained in 5 of 6 defects, and 80% was obtained in 1 of 6 defects, The mean root coverage was 96,6% in six cases on 4 patients. 2. The mean root coverage was 3.83mm and mean recession depth decreased from 4mm to 0.16mm. 3. The mean width of clinical attached gingiva increased from 1.5mm to 4mm. The mean width of gained attached gingiva after surgery was 2.5mm. 4. The mean follow up period was 36.5 months. The longest follow up period was 50 months and the shortest follow up period was 22 months. 5. The result that obtained by surgery was stable during follow up period. Within the above results, root coverage with SCTG is an effective procedure to cover marginal tissue recession defect with long term stability.

• Journal of Chest Surgery
• /
• 제29권8호
• /
• pp.844-849
• /
• 1996

본 연세대학교 심장혈관센타에서는 1992년 I월부터 1993년 12월가지 체외순환을 시행하여 완전교정 을 시행한 복잡심장기형 환아 198명중 22예에서 복막투석을 시행하였다. 이들의 나이는 10일에서 6세 (평균 14.8$\pm$ 17.8개월)이었으며 복막투석의 적응증으로는 수분과부하상태가 10예, 혈장칼릅치가 5. Smmo111 이상인 경우가 3예, 그리고 충분한 양의 이뇨제를 투여함에도 소변양이 Imllkglhr 이하가 시간 이상 지속된 경우 9예에서 시행하였다. 체외순환이 90분 이상인 경우와 그 이하인 경우를 비교할 때 90분 이상 시행한 경우에 의미있게 많이 복막투석을 필요로 하였다(P<0.05). 1개월 미만 환아 13예중 5예(38%)에서 시행하였으나 그 이상의 나이와 비교할 때 의미있게 높지는 않았다(p : 0.08). 16예에서 신기능이 회복되었으나 4명은 호흡부전 또는 폐혈증으로 사망하였고 신기능이 회독되지 않 은 6예는 저심박출증이나 폐부종 등으로 모두 사망하였다. 아직도 사망률은 높으나 체 외순환 후 빈뇨, 수분과부하, 또는 고칼륨증이 있을 때에는 조기에 복막투석을 시행하는 것이 환자 치료에 도움이 되리라 사료된다.

• 가정과삶의질연구
• /
• 제7권2호
• /
• pp.199-212
• /
• 1989

The main purpose of this paper is to investigate the factors which affect the alienation of the aged, and to study the relative importance of these factors. This study focused on the following research questions: 1) How do the demographic variables(sex, marital status, family structure, religion, economics, prior occupation, education level) affect the alienation of the aged? 2) How the alienation of the aged is affected by their involvement in social activities? 3) Does the degree of satisfaction with family relationship have a perceivable impact on the alienation of the aged? 4) How does the self-rated senescence affect the alienation of the aged? The research was practiced from the 18th Sept. 1999 to the 30th Sept. 1988, through individual interviews with 300 elderly people, all living in Seoul area. Among them only 285 were used in the analysis. The major findings of the study are as follows; 1) The sex of the respondents makes no difference in the alienation of the age . 2) Marital status is found to be relatively significant in determining the alienation. The degree of alienation of old people with spouse is substantially lower than that of those without spouse. 3) Family structure was found to have no significantly effect on the alienation of the aged. 4) Involvement in religion was found to significantly reduce the alienation of the aged. 5) Econimic factors seems to be critical in defermining the aged. The amount of pocket money avaliable for daily use has direct relationship with alienation. 6) Prior occupation was found to be another significant factor affecting alienation professionals experience far lower alienation than nonprofessionals. 7) The higher is education level, the lower is the alienation of the aged. 8) Active participation in social activities and good relationship with other family members were founded to contribute to lowering the alienation of the aged. Whereas, too much concern over one's senescence appears to hav negative effects on the alienation. The regression analysis shows that the satisfaction with the family relationship has the most important influence upon the alienation of the aged. Following are the factors of self-rated senescence, pocket money in a descending order. All these factors, which explain 42.65% of the total variance of alienation variable are statistically significant(p<.001)

• 약학회지
• /
• 제42권6호
• /
• pp.576-582
• /
• 1998

Fenfluramine, an anorectic agent, is widely abused as a diet pill in Korea because it is freely marketed in China without any regulation. The optical isomers of fenfluramine hav e different phamacological actions: d-form is used as an anorectic agent, while l-form as a neuroleptic agent. To investigate the metabolism when racemic fenfluramine was administered orally, the urinary excretion of fenfluramine was studied in rats. The enantiomeric separation of fenfluramine was performed on achiral column by gas chromatography using (S)-N-(trifluoroacetyl)-l-prolyl chloride (TFP) as a derivatizing agent. After administration of 15mg/kg of racemic fenfluramine to rats, d-, l-fenfluramine and its metabolites d- and l norfenfluramine in urine were determined by chromatographic separation of TFP derivatives on DB-1 at retention time of 11.2, 11.8, 8.4 and 8.6 min respectively. Urinary recoveries of d and l-fenfluramine in rat were 0.42-5.9O% and 0.18-1.20% respectively in urine specimens collected during first 24hr. The comparison in the levels of isomers showed that d- fenfluramine were higher than l-form, while d-norfenfluramine were lower than l-form. The ratios between parent compound and metabolite revealed that d-norfenfluramine to d-fenfluramine ranged from 1.0 to 4.4, while the ratio of l-norfenfluramine to l-fenfluramine was 8.2-21.1 indicating that l-fenfluramine is metabolized faster than the d-isomer.