• Nuclear Engineering and Technology
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• 제31권5호
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• pp.498-505
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• 1999

Trivalent actinide-lanthanide group separation is difficult to perform on an industrial scale, because of the many drawbacks of the available chemical process. In this paper, picolinamide(C$_{8}$H$_{17}$) is synthesized and characterized, and extraction yields of Am-241, Eu-152 and Nd are determined in batch extraction experiments. In particular, the influence of the solvent is described. The extraction yields of Am-241, Eu-152 and Nd depended on the LiNO$_3$ concentration, the picolinamide(C$_{8}$H$_{17}$) concentration and the acidity. A favorable picolinamide(C$_{8}$H$_{17}$) concentration was found to be about 2M. The appropriate nitric acid concentration and LiNO$_3$ concentration were confirmed to be about 0.125M and 3M, respectively. The separation factor of Am and Eu was about 9.9 at optimum conditions. The picolinamide(C$_{8}$H$_{17}$) is a very promising extractant for the actinide(III)-lanthanides(III) separation.aration.aration.

• 한국재료학회지
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• 제7권3호
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• pp.251-264
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• 1997

공진 주파수 온도 계수($\tau$$_{f}$)가 큰 음의 값을 가지는 (Li$_{1}$2Nd$_{1}$2)TiO$_{3}$(LNT) 고주파 유전체를 125$0^{\circ}C$에서 140$0^{\circ}C$까지의 온도에서 2시간동안 소결을 하였고 소결후에는 소결온도보다 약간 낮은 120$0^{\circ}C$에서 5시간 동안 annealing을 실시를 하였다. 그리고 열처리에 의한 상, 미세구조의 변화를 X-ray, SEM을 통해서 분석하였으며, 열처리가 고주파 유전물성에 대해 미치는 영향에 대해서도 고찰하였다. 130$0^{\circ}C$에서 135$0^{\circ}C$ 근방에서 소결시킨 재료는 Annealing효과에 의해 소결체에 균일한 입도 분포가 증진되었고 체적 밀도가 향상되었으며, 열처리 효과에 의해 품질계수(Q)값이 향상되었고 유전상수($\varepsilon$$_{r}$)는 약간 감소하였으며 공진주파수 온도계수($\tau$$_{f}$)는 더 큰 음의 값을 가지게 되었다. 그러나 135$0^{\circ}C$이상에서 소결한 경우에는 비정상적인 입자 성장에 의해 밀도가 감소되며, 이에 따라 고주파 유전특성이 전반적으로 저하되었다.었다.

• Bulletin of the Korean Chemical Society
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• 제13권6호
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• pp.593-595
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• 1992

To improve the lifetime and output power in a sealed-off $CO_2$ laser, a series of Nd$_{1-x}$Sr$_x$CoO$_3$(x = 0.0, 0.25, 0.40, 0.50, 0.60, 0.75) perovskite-type compounds has been synthesized and used for a cathode material. Using a typical method samples were sintered at 1150$^{\circ}$C and their structures were determined as a cubic form by means of XRD analysis. The degrees of $CO_2$ dissociation were measured by PAS (photoacoustic spectroscopy) with the lapse of time. In the case of $Nd_{0.4}$Sr$_{0.6}$$CoO_3$, which showed the highest catalytic cathode effect, only 7% of the initial $CO_2$ concentration were dissociated at 30 torr of gas mixture and 5 mA of discharge current. The more the gas pressure decreased and the discharge current increased, the more the degree of dissociation occurred. The ability of catalytic cathode to regenerate CO$_2$ in the laser cavity lies in order for x, 0.60 > 0.50 > 0.40 > 0.75 > 0.25 ${\gg}$ 0.0. Except for the case of x = 0.0 the amounts of $CO_2$ dissociation were found to be within 7-15% of the initial $CO_2$ concentration.

• 생물정신의학
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• 제3권2호
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• pp.262-268
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• 1996

It has been known that clozapine is more selective mesolimbic dopamin $D_2$ receptor antagonist and related to 5-HT receptor. In this study, we wxamined the plasma homovanillic acid(HVA), serotonin(5-HT), and 5-hydroxyindoleacetic acid(5-HIM) levels in refractory schizophrenics during clozapine treatment. And we assessed the effects of clozapine on these plasma monoamine metabolites and their association with psychopathology and treatment response. Eight refractory schizophrenic patients(DSM-IV) have entered the study for 3 months during clozapine treatment. Patients were admitted to the inpatient sevice and withdrawn from all neuroleptics for 7-14 days but exceptionally occasional doses of lorazepam was given if needed for behavioral control. The dose of clozapine was titrated as tolerated to 800mg/day. The plasma HVA. 5-HIM and 5-HT levels were measured before treatment and following 2nd week, 4th week, 8th week, and 12th during treatment. Psychopathology was assessed with Brief Psychiatric Rating Scale (BPRS) and Positive and Negative Synrome Scale(PANSS) before and during clozapine treatment. During clozapine treatment, no statistically significant changes were found in plasma HVA, 5-HIM, 5-HT levels, and HVA/5-HIM ratio between baseline and following 2nd week, 4th week, 8th week, 12th week. However, the change in plasma 5-HIAA/5-HT ratio from baseline to 4th week was statistically significant. Generally, changes of plasma HVA, 5-HIAA, 5-HT levels and HVA/5-HIAA ratio were not associated with psychopathology but 5-HIAA was associated with in positive symptoms and general psychopathology of PANSS. These results suggest that clozapine has been found to have relatively weak dopaminergic blokade and stronger serotonergic antagonism.

• 대한소아치과학회지
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• 제26권2호
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• pp.377-398
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• 1999

불소도포시 주로 형성되는 calcium fluoride는 구강내 환경에서 pH에 의해 조절되는 불소의 저장고 역할을 하여 치아우식 예방에 있어서 중요한 역할을 하는 것으로 알려져 있다. 따라서 불소도포의 우식예방 효과는 calcium fluoride를 얼마나 많이 형성시켜 오래 지속시키는 가에 달려 있다. 이에 치아 내산성 증가에 효과 있다고 알려진 Nd:YAG 레이저 조사가 calcium fluoride형성 및 치아 내산성에 미치는 영향에 대해 알아보기 위해서 실험을 시행하였다. 소의 영구전치에서 276개의 시편을 제작하여 아무런 처치를 하지 않은 군을 대조군으로 하고 1.23% acidulated phosphate fluoride (APF) 5분, 30분 도포 및 Nd:YAG 레이저 조사에너지 밀도 $20J/cm^2,\;40J/cm^2$의 조건에 따라 불소 도포군, 레이저 조사군, 불소 도포후 레이저 조사군, 레이저 조사후 불소 도포군으로 분류하였다. 불소도포를 시행한 경우 이를 다시 KOH 처리 여부에 따라 나누어 23개의 실험조건을 만들었다. 각 실험조건에 12개의 시편을 배정하고 이중 10개의 시편은 불소 및 무기인 측정에, 나머지 2개의 시편은 표면 관찰에 사용하였다. KOH 비처치군에서 0.1 N HClO4로 enamel biopsy를 시행하여 탈회 법랑질의 불소농도 및 탈회깊이를 측정하였으며 KOH 처치군에서는 1 M KOH로 24시간 처리하여 calcium fluoride를 정량 후 enamel biopsy를 시행하였다. 실험결과 얻어진 자료 및 주사 전자현미경 관찰 소견을 비교하여 다음의 결과를 얻었다. 1. KOH 비처치군에서 탈회된 법랑질의 불소농도는 레이저조사 후 불소도포시 레이저 에너지 밀도 증가에 따라 증가되는 경향을 보였다. 2. KOH 비처치군에서 법랑질 탈회깊이는 불소를 5분 도포후 레이저 $20J/cm^2$를 조사한 경우를 제외하고는 레이저와 불소를 병행하여 처치시 각각을 단독으로 처치시보다 탈회깊이가 작았다 (p<0.05). 3. Calcium fluoride의 양은 레이저의 조사에 의해 유의 있게 증가하지 않았다 (p>0.05). 4. Calcium fluoride 입자는 불소만 도포한 경우에 비해 레이저 조사후 불소도포시 입자크기가 증가되었으며, 불소도포후 레이저 조사시 입자크기의 증가와 함께 일부 융합된 양상을 보였다. 5. KOH 처치군에서 법랑질의 불소농도는 불소를 30분 도포후 레이저를 조사한 경우를 제외하고는 대조군의 불소농도와 유의한 차이가 없었다(p>0.05). 6. KOH 처치군에서 불소와 레이저를 병행한 경우, 불소만 도포한 경우보다 탈회된 법랑질의 깊이가 작았다 (p<0.05). 7. KOH 비처치군에서 탈회된 법랑질의 불소농도와 탈회깊이의 상관관계(Spearman correlation coefficient: -0.6281)는 KOH 처치군(Spearman correlation coefficient: -0.3792)에 비해 높은 음의 상관 관계를 보였고, 동일한 조건으로 불소도포 및 레이저 조사를 시행한 경우에 있어서 KOH 처리 여부에 따른 탈회법랑질 깊이의 유의차가 있는 경우 calcium fluoride의 형성량이 많았다. 이상의 실험결과로 미루어 보아 레이저 조사가 calcium fluoride의 형성량에 영향을 미치지 않았으나 레이저 조사의 영향으로 calcium fluoride의 용해가 감소하는 것으로 판단된다. 또한 불소도포 및 레이저 조사의 병행은 각각을 단독으로 처치한 경우에 비하여 치아 내산성 증가면에서 유리하므로 임상에서 불소도포주기 연장과 같은 유용한 결과를 얻을 수 있을 것으로 생각된다.

• 한국재료학회지
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• 제12권8호
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• pp.617-623
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• 2002

In order to improve the hydrogen storage capacity and the activation properties of the hydrogen storage alloys, the rare-earth metal alloy series, $MmNi_{ 4.5}$$Mn_{0.5}$ $Zr_{x}$ (x=0, 0.025, 0.05, 0.1), are prepared by adding the excess Zr in $MmNi_{4.5}$ $Mn_{0.5}$ / alloy for the strong resistance to intrinsic degradation. The hydrogen storage alloys of rare-earth metal such as $LaNi_{5}$ , and $MmNi_{5}$X and $MmNi_{4.5}$ /$_Mn{0.5}$ alloys which substituted La by misch metal properties were characterized as well. The hydrogen storage alloys were produced by melting each metal mixture in arc melting furnace, and the as-cast alloys were heat-treated at $1100^{\circ}C$ for 10 hr. The major elements of misch metal(Mm) were La, Ce, Pr and Nd with some impurities less than 1wt.% determined by ICP-AES. X-ray diffraction indicated that the structure for these samples was a single phase of hexagonal with $CaCu^{5}$ type. As the Zr contents increases, the activation time and the plateau pressure decrease and sloping of the plateau pressure increase. Amount of the 2nd phases increases with increase in Zr contents in $MmNi_{ 4.5}$$Mn_{0.5}$ $Zr_{0.1}$ alloy, This phenomenon indicated that $ZrNi_3$ in this phase, which shows the maximum storage capacity and the strong resistance to intrinsic degradation, is considered as a proper alloy for hydrogen storage..

• 환경위생공학
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• 제20권1호
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• pp.76-83
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• 2005

The process of reusing the treated water generated during this process and that of recovery of molybdenum from the excessive water were studied. The results were as follows. Molybdenum recollection 1. Reusing processing water generated after dissolving process on FL/20 type, the following were the remaining Mo.'s weights after the 1st, 2nd, 3rd, 4th, 5th, & 6th dissolutions respectively. 1) The result of measuring the quantity of Mo. in processing water(the 1st solving water) generated after the 1st dissolving Mo. process was $369g/\ell$ 2) The result of measuring the quantity of Mo. in processing water(the 2nd solving water) generated after the 1st dissolving Mo. process reusing the 1st solving water was $627.3g/\ell$ 3) The result of measuring the quantity of Mo. in processing water(the 3rd solving water) generated after the dissolving Mo. process reusing the 2nd solving water was $808.11g/\ell$ 4) The result of measuring the quantity of Mo. in processing water(the 4th solving water) generated after the dissolving Mo. process reusing the 3rd solving water was $934.68g/\ell$ 5) The result of measuring the quantity of Mo. in processing water(the 5th solving water) generated after the dissolving Mo. process reusing the 4th solving water was $1023.27g/\ell$ 6) The result of measuring the quantity of Mo. in processing water(the 6th solving water) generated after the dissolving Mo. process reusing the 5th solving water was $1085.29g/\ell$ 2. The followings were the results of recollectings Mo. in processing water respectively generated after dissolving Mo. to produce complete goods df FL/20 type filament. 1) the percentage of recollecting Mo. in the 1st solving water was $93.0\%$ 2) the percentage of recollecting Mo. in the 2nd solving water was $94.5\%$ 3) the percentage of recollecting Mo. in the 3rd solving water was $95.5\%$ 4) the percentage of recollecting Mo. in the 4th solving water was $96.0\%$ 5) the percentage of recollecting Mo. in the 5th solving water was $96.2\%$ 6) the percentage of recollecting Mo. in the 6th solving water was $96.4\%$ 3. The followings were the results of analyzing, with ICP, holding quantities of Mo. in the 6 processing waters to produce FL/20 type filament after passing a 3 staged solid-liquid separator through, dehydrating and drying for more than 3 hours in a dryer to recollect solving Mo. in them 1) the Mo. holding percentage in the 1st solving water was $76.6\%$ 2) the Mo. holding percentage in the 2nd solving water was $76.6\%$ 3) the Mo. holding percentage in the 3rd solving water was $76.6\%$ 4) the Mo. holding percentage in the 4th solving water was $76.6\%$ 5) the Mo. holding percentage in the 5th solving water was $76.6\%$ 6) the Mo. holding percentage in the 6th solving water was $76.6\%$ It was noted that with the number of times the recollecting Mo. percentage become higher, and in spite of much recollecting, without any large effect on the goods the solving water could be reused as the processing water. Because the collected Mo. holding percentages were more than $76\%$, it is considered they are very good one than Chinese Mo. ores with $50\%$ degrees of purity, worthy of recollecting Mo.

• Clinical and Experimental Pediatrics
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• 제50권4호
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• pp.381-385
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• 2007

목 적 : 우리나라에는 전통적으로 내려오는 한약에 대한 선호도가 매우 강하여 남용의 우려가 있다. 이로 인한 의료비 지출 증가 우려와 의료질서의 왜곡현상 마저 생기고 있으나 이에 대한 자료가 부족하여 저자는 초등학교 학생들의 한약 이용 실태에 대한 연구를 실시하였다. 방 법 : 광주 소재 3개의 초등학교 1,508명의 학생들을 대상으로 설문조사를 시행하였다. 설문지가 회수된 905명의 학생들을 대상으로 분석하였다. 결 과 : 남아는 421명, 여아는 484명이었고 출생 후 자녀에게 한약을 먹여본 경우는 590명(65.2%)이었으며, 학년별로는 1학년 74.1%, 2학년 63.0%, 3학년 64.8%, 4학년 63.3%, 5학년 65.5%, 6학년 61.9%였다. 한약의 평균 복용 횟수는 3.2회였으며 6학년은 3.3회, 5학년은 3.9회, 4학년은 3.7회, 3학년은 2.7회, 2학년은 2.7회, 1학년은 2.6회였다. 한약 1회 복용시 평균 비용은 5-10만원이었다. 처음 한약 복용 평균 연령은 55개월이었으며, 6학년은 67개월, 5학년은 58개월, 4학년은 54개월, 3학년은 55개월, 2학년은 51개월, 1학년은 47개월이었다. 한약 복용 이유의 가장 흔한 것은 '병이 없지만 몸이 허약해 보여서'였다. 한약 복용 후 효과를 보았다고 생각한 경우는 63.7%였고, 부작용이 발생한 경우는 4.5%였다. 결 론 : 초등학교 학생들의 한약 복용 비율이 높았으며, 저학년으로 갈수록 한약 복용 비율이 증가하고, 초회 복용 연령도 훨씬 낮아지고 있다. 따라서 임상 의사들이 한약복용에 대해 더 많은 관심을 가지고 연구되어야 할 것으로 생각된다.

• 한국식품조리과학회지
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• 제28권5호
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• pp.515-530
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• 2012

This research aims to audit foodservice sanitation management practices and to assess microbiological quality of foods and their food contact environments in kindergartens. Sanitation auditing was conducted in 10 kindergartens in Seoul, Gyeonggi, and Incheon areas to assess the levels of safety practices. Results revealed that the surveyed kindergartens scored 41.4 out of 100 points, on average. The average scores of each category were 6.4/11 (58.1%) for facilities sanitation, 4.2/12 (35.0%) for equipment sanitation, 2.4/10 (24.0%) for personal hygiene, 5.1/10 (51.0%) for food ingredients management, 6.0/17 (35.3%) for production process, 5.4/10 (54.0%) for environmental sanitation, 2.0/6 (33.3%) for kitchen utensils sanitation, and 2.2/6 (96.7%) for safety management. Microbiological quality of raw, prepared foods, personal sanitation (hands), environmental sanitation, and drinking water were assessed. Total plate counts (TPC) of the following menus exceeded the critical limit: seasoned leek (5 log CFU/g), cucumber (5.0 log CFU/g), panbroiled fish paste (TNTC at $10^4$), tangpyeongchae (5.3 log CFU/g), egg rolls (6.1 log CFU/g), panbroiled sausage (TNTC at $10^4$), and soft tofu pot stew (TNTC at $10^4$). Coliform which exceeded the standard limit were detected from seasoned leek (2 log CFU/g), cucumber (2.5 log CFU/g), panbroiled fish paste (2.0 log CFU/g), egg roll (3.8 log CFU/g), tangpyeongchae (4.0 log CFU/g), panbroiled sausage (2.3 log CFU/g), and soft tofu pot stew (3.7 log CFU/g). For seasoned foods (muchim), S. aureus ranged 2.2~2.9 log CFU/g. In food workers' hands, microbial profiles ranged 3.8~7.9 log CFU/hand for TPC, ND~4.5 log CFU/hand for coliforms, ND~4.7 log CFU/hand for S. aureus, and ND~5.3 log CFU/hand for Enterobacteriaceae. Microbiological profiles of food contact surface of knives, cutting boards, dish-clothes, and trays showed possibilities of cross-contamination. General bacteria were 2.1~4.5 logCFU/ml in 4 purified water samples and E. coli were found in the kitchen of one kindergarten. These results suggested that environmental sanitation management practices need more strict improvement: effective sanitation education methods and practices were strongly required, and more strict sanitation management for cooking utensils and equipment were required.

• 한국응용곤충학회지
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• 제31권4호
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• pp.543-550
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• 1992

Buprofezin(25% WP)의 처리약량에 따른 벼멸구 유충에 대한 약효지속기간 및 buprofezin이 벼멸구 유충에 미치는 생물학적 영향을 폿트실험으로 조사하여 다음과 같은 결과를 얻었다. Buprofezin의 벼멸구 2령유충에 대한 약효지속효과는 상당히 길며, 처리농도가 높을수록 약효지속기간도 길었다. 17.5 g a.i./10 a 처리는 약처리 35일후에도 90%정도의 살충효과를 유지하였고, 5.78~11.50 g a.i./10 a 처리는 $RLT_{90}$(90% 이상 상충률을 유지하는 약처리후 경과시간)이 9.0~13.5일, $RLT_{50}$(50% 이상 살충률을 유지하는 약처리후 경과시간)은 16.8~22.8일로 추정되었다. 그리고 벼멸구 2령유충에 대하여 약처리 15일까지 95%이상의 살충력을 유지할 수 있는 buprofezin 처리약량은 13.00 g a.i./10 a이었고, 50%이상의 살충력을 유지할 수 있는 처리약량은 4.44 g a.i./10 a로 추정되었다. Buprofezin 7.0 g a.i./10 a 처리는 벼멸구 1령유충에 대하여 약처리 17일후까지 100%의 살충률을 유지하였으며 1령유충에 대한 $RLT_{50}$은 32.5일로 같은 농도의 2령 약충에 대한 $RLT_{50}$보다 15일정도 길었다. Buprofezin(7.0 g a.i./10 a)은 처리당시 4령까지의 유충을 100% 치사시켰고, 5령유충에 대해서는 우화전까지 약 70%의 살충력을 보였으나 5령이 생존하여 우화한 성충암컷은 수명이 현저하게 감소하였고 전혀 산란을 하지 못하였다.