• 한국의학물리학회지:의학물리
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• 제28권3호
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• pp.106-110
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• 2017

The variable density phantom fabricated with varying the infill values of 3D printer to provide more accurate dose verification of radiation treatments. A total of 20 samples of rectangular shape were fabricated by using the $Finebot^{TM}$ (AnyWorks; Korea) Z420 model ($width{\times}length{\times}height=50mm{\times}50mm{\times}10mm$) varying the infill value from 5% to 100%. The samples were scanned with 1-mm thickness using a Philips Big Bore Brilliance CT Scanner (Philips Medical, Eindhoven, Netherlands). The average Hounsfield Unit (HU) measured by the region of interest (ROI) on the transversal CT images. The average HU and the infill values of the 3D printer measured through the 2D area profile measurement method exhibited a strong linear relationship (adjusted R-square=0.99563) in which the average HU changed from -926.8 to 36.7, while the infill values varied from 5% to 100%. This study showed the feasibility fabricating variable density phantoms using the 3D printer with FDM (Fused Deposition Modeling)-type and PLA (Poly Lactic Acid) materials.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.421-421
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• 2008

Generally, the polymer thick-film resistors for embedded organic or hybrid substrate are patterned by screen printing so that the accuracy of resistor pattern is not good and the tolerance of resistance is too high(${\pm}$20~30%). To reform these demerits, a method using Fodel$^{(R)}$ technology, which is the patterning method using a photosensitive resin to be developable by aqueous alkali-solution as a base polymer for thick-film pastes, was recently incorporated for the patterning of thermosetting thick-film resistor paste. Alkali-solution developable photosensitive resin system has a merit that the precise patterns can be obtained by UV exposure and aqueous development, so the essential point is to get the composition similar to PSR(photo solder resist) used for PCB process. In present research, we made the photopatternable resistor pastes using 8 kinds of epoxy acrylates and a conductive carbonblack (CDX-7055 Ultra), evaluated their developing performance, and then measured the resistance after final curing. To become developable by alkali-solution, epoxy acrylate oligomers with carboxyl group were prepared. Test coupons were fabricated by patterning copper foil on FR-4 CCL board, plating Ni/Au on the patterned copper electrode, applying the resistor paste on the board, exposing the applied paste to UV through Cr mask with resistor patterns, developing the exposed paste with aqueous alkali-solution (1wt% $Na_2CO_3$), drying the patterned paste at $80^{\circ}C$ oven, and then curing it at $200^{\circ}C$ during 1 hour. As a result, some test compositions couldn't be developed according to the kind of oligomer and, in the developed compositions, the measured resistance showed different results depending on the paste compositions though they had the same amount of carbonblack.

• 대한영양사협회학술지
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• 제5권2호
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• pp.175-181
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• 1999

The present study was conducted to evaluate nutrient intakes of industrial workers with hyperlipidemia and cholesterol-saturated fat indices(CSI) of their daily meals and various side dishes accompanied with alcohol. Thirty eight male subjects of 41.0$\pm$6.5 years whose average serum cholesterol and triglyceride levels were 222.9$\pm$37.7 and 282.3$\pm$139.3mg/이 were interviewed on daily intakes of foods and drinking habits including types and amounts of side dishes using 24-hour recall and questionnaire methods. Average energy habits including twenty six non-drinkers and twelve drinkers were 2365$\pm$41 and 2822$\pm$417kcal, respectively but intakes of other nutrients were not very different between two groups. Carotene intakes was, however, low in drinkers. Intakes of saturated fat, cholesterol and CSI of subjects' daily meals were 15.4$\pm$5.4g, 229$\pm$114mg and 27.1$\pm$10.4 for non-drinkers and 18.7$\pm$7.8g, 238$\pm$69mg and 30.8$\pm$9.8 for drinkers. CSI of their daily meals varied from 10 to 60 without much differences in energy values and were positively correlated with serum cholesterol levels(r=0.2606, p<0.05). Average alcohol intakes obtained from subjects' drinking habit was 89.5$\pm$46.8g per day and major side dish was roasted beef giving 660$\pm$234kcal of energy and 24.3$\pm$8.0 of CSI. From the present study, it is concluded that industrial workers are more prone to have hyperlipidemic diets due to alcohol. To improve their diet and health, an appropriate nutrition education should be necessary and CSI of various Korean foods and meals can be used as handy self-control education tool.

• 한국재료학회지
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• 제22권2호
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• pp.103-109
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• 2012

Red-emitting $Eu^{3+}$-activated $(Y_{0.95-x}Al_x)VO_4$ (0 < x $\leq$ 0.12) nanophosphors with the particle size of ~30 nm and the high crystallinity have been successfully synthesized by a hydrothermal reaction. In the synthetic process, deionized water as a solvent and ethylene glycol as a capping agent were used. The crystalline phase, particle morphology, and the photoluminescence properties of the excitation spectrum, emission intensity, color coordinates and decay time, of the prepared $(Y_{0.95-x}Al_x)VO_4:Eu^{3+}$ nanophosphors were compared with those of the $YVO_4:Eu^{3+}$. Under 147 nm excitation, $(Y_{0.95-x}Al_x)VO_4$ nanophosphors showed strong red luminescence due to the $^5D_0-^7F_2$ transition of $Eu^{3+}$ at 619 nm. The luminescence intensity of $YVO_4:Eu^{3+}$ enhanced with partial substitution of $Al^{3+}$ for $Y^{3+}$ and the maximum emission intensity was accomplished at the $Al^{3+}$ content of 10 mol%. By the addition of $Al^{3+}$, decay time of the $(Y,Al)VO_4:Eu^{3+}$ nanophosphor was decreased in comparison with that of the $YVO_4:Eu^{3+}$ nanophosphor. Also, the substitution of $Al^{3+}$ for $Y^{3+}$ invited the improvement of color coordinates due to the increase of R/O ratio in emission intensity. For the formation of transparent layer, the red nanophosphors were fabricated to the paste with ethyl celluloses, anhydrous terpineol, ethanol and deionized water. By screen printing method, a transparent red phosphor layer was formed onto a glass substrate from the paste. The transparent red phosphor layer exhibited the red emission at 619 nm under 147 nm excitation and the transmittance of ~80% at 600 nm.

• 한국산업보건학회지
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• 제6권2호
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• pp.272-280
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• 1996

This study was to evaluate the associations between urinary S-Phenyl-mercapturic acid(S-PMA) as a new indicator of biological monitoring for low level of exposure to benzene and independent variables such as the air concentration of benzene in the breathing zone of workers, the years of work, and smoking. In this study the subjects were the total of 145 drawn from 53 workers who were occupationally exposed to benzene and 92 workers who were not. The results were as follows: 1. In the workplace geometric mean concentration of benzene in the breathing zone of workers was 0.31 ppm(0.02 - 3.26 ppm) for the spraying workers and 0.25 ppm(0.02 - 3.95 ppm) for the printing workers. 2. The geometric mean of uninary S-PMA for non exposed group was $8.9{\mu}g/g$ creatinine($0.6-72.3{\mu}g/g$ creatinine), 80.3% (74 workers) of the total non-exposed workers indicated less than $20{\mu}g/g$ creatinine of uninary S-PMA. The difference of uninary S-PMA by sex, age, smoking was not significant. 3. The geometric mean of urinary S-PMA for workers who were exposed to benzene was $37.2{\mu}g/g$ creatinine, and was four times higher than that of workers who were not exposed. And 79.3% (42 workers) of the total exposed workers indicated more than $20{\mu}g/g$ creatinine of urinary S-PMA. 4. Regarding the level of benzene in the air, urinary S-PMA was the highest level of $147.9{\mu}g/g$ creatinine in the workers who were exposed to air concentration of 0.5 ppm of benzene and was higher as the level in the air was increased. 5. The correlation coefficient between log urinary S-PMA and log benzene concentration in the breathing zone was 0.80, and the following linear equation was found between urinary log S-PMA and log benzene concentration in the breathing zone : log S-PMA(${\mu}g/g$ creatinine) = 0.564 log benzene in air(ppm) + 0.192 (n=53, r=0.80, p=0.000) In conclusion, the concentration of S-PMA in urine proved to be good parameter for biological monitoring benzene exposure at the workplace even at low level of benzene in air.

• 한국구조물진단유지관리공학회 논문집
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• 제24권2호
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• pp.103-110
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• 2020

본 연구는 바인더젯 3D 프린팅 출력물의 강도증진을 위하여 진공함침 후처리 공정의 적용성을 검토하였다. 또한, 출력물 크기에 따른 강도발현 한계를 확인하기 위하여 10 mm, 20 mm, 30 mm 및 40 mm 큐빅 출력물을 대상으로 침투성, 부피밀도 및 압축강도를 확인하였다. 그 결과, 진공함침 후처리 공정에서 최대압력이 증가함에 따라 후처리 용액이 출력물 내부까지 침투하게 되고 이에 따라서 침투면적률이 개선되는 것을 확인하였다. 출력물 압축강도율과 후처리 용액 침투면적률은 보정결정계수 0.992의 지수함수 형태의 상관관계를 나타내고 있다. 또한, 부피밀도가 증가하였으며 이는 후처리 용액이 내부까지 침투한 것으로 유추할 수 있다. 결론적으로 바인더젯 3D 프린팅 출력물의 강도증진을 위해서는 출력물 내부까지 후처리 용액을 침투하는 것이 필수적이며, 이를 위한 유효한 방법으로써 진공함침을 제안한다.

• 한국수산과학회지
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• 제30권3호
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• pp.377-387
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• 1997

해수로 유출되고 있는 유기인제 살충, 살균제의 형광 분석법에 의한 finger print식 분석 방법을 개발하기 위해, 벼 농사에 가장 많이 사용되어지는 Hinosan과 Kitazin을 포함하는 10가지의 표준 용액을 조제하여, 형광 특성을 측정하였다. $220nm\~520nm$ 구간의 흡수 파장을 이용하여, 여기 (excitation)시켜 얻은 형광스펙트럼들을 이차원 평면 위의 형광세기 표시를 등고선 모양으로 표시하였다. 이 contour들은 각 조사된 유기인제에 대해 특징적인 형태로 관찰되었다. 조사된 10가지의 유기인제 농약의 형광 contour들은, 봉우리가 한 개로 된 DDVP를 포함한 8가지의 유기인제와 두 개의 봉우리로 나타난 Ateric을 포함한 두 가지의 유기인제 농약으로 나뉘어진다. 또한 최대 흡수파장의 영역별로 보면, 단일한 봉우리를 보이는 많은 유기인제는 약 280nm에, Ateric을 포함한 두 종류의 유기인제는 260nm에서, 그리고 장파장에서 최대 형광파장을 보여준 Monopho, Thaconyl의 최대 흡수파장은 비교적 장파장쪽으로 치우친 300nm와 340nm인, 다른 유기인제의 최대 형광파장과 서로 겹치지 않는 영역에서 나타났다. 그러나, 280nm에서 최대 흡수파장을 나타내는 유기인제 중에 Kitazin, Locsion, Meta는 약 2nm이하의 근소한 차이를 두고 최대 형광세기를 308nm주변에서 나타내었다. 이러한 그룹의 분별을 위해, HPLC-형광 자료를 이용하면 용리시간 차이에 의한 분리와 identification이 가능했다. 형광 contour가 매우 유사한 Kitazin, Locsion과 Meta를 비교하면, Kitazin은 $16\~20$분 대에 나타나는 peak들이 매우 미약할 뿐 아니라, 용리시간 9.6분에 나타난 현저한 단일 peak가 다른 형광 특성이 비슷한 유기인제인 Locsion이나 Meta와의 구분이 용이하게 해 준다. 그러나, Locsion과 Meta는 chromatogram의 용리시간이나, 세부적인 작은 peak 특징은 다르나, 그 pattern이 유사하여, 분석상 불확실성이 내재될 가능성이 있다.

• 한국직업건강간호학회지
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• 제3권호
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• pp.54-70
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• 1993

According as the automation of clerical work(OA ; Office Automation) develops, the use of VDT(Visual or Video Display Terminal) is increasing suddenly. But, in proportion to the spread of office automation(OA tendency), the self-conciousness syptom attendant upon the work is appearing also (Kim, Jung Tae, Lee, Young Ook, 1990). The apparatuses of office enable the clerical workers to be convenient and perform mass businesses. But, they are increasing the opportunity to be exposed to VDT syndrom, techno stress, computer terminal disease, pain by muscle strain(RSI), bradycausia of noise nature, and electromagnetic waves, etc. which are referred to as the new type of occupational diseases to the workers. It is the real situation that the workers to use VDT is complaining of the physical inconvenience sense in the recent newspaper and literature, it is the point of time that the sydrome to come from VDT use and computer terminal disease, etc. must be classified into the occupational disease(Lee, Kwang Young 1990, Lee, Kyoo Hak 1990, Lee, Won Ho 1991, Lee, Si Young 1991, Lee, Joon 1991, Choi, Young Tae 1991, Heo, Seung Ho 1989). In addition, it is the real situation that the scientifitic study result about the scope that electromagnetic waves has influence on the human body has not been suggested yet, and criticism on the stable exposure permission standard about electromagnetic waves to be emitted from VDT and on the problem in the health about electromagnetic waves is continuing. (IEEE Spectrum, 1990). In addition according to the experience of nursery business of industry field, it is the real situation that the patients who consult complaining of physical and mental inconvenience sence, among the users of apparatus of office automation, are reaching 10% of the patients coming to doctor's room. Therefore, it is necessary to confirm the self-consciousness symptom that the clerical workers complain of multilaterally with the actual state examination about the use of the apparatuses of offices automaton. Thus, this study was tried as th basic data for the cosultation and education for the maintenance and furtherance of the health of workers as the nurse of industry field, by confirming the contents of self-consciousness symptom attendant upon the use of the apparatus for office outomation making the financial institution in which the spparatus for office automation in most frequently used as the subject, and by examining whether there is the difference according to the subject of study, the data were collected, by using the questionnaire method, making 200 workers who consented to the study participation as the subject, among the persons who have spent over 3 months since they used the apparatuses for office automation and didn't receive the treatment in hospital due to the clerical disease for recent 3 years. The period of data collection was from Oct. 9, 1991 to Oct. 12. As for the measurement instrument about the complaint if self-consciousness symptom attendant upon the use of apparatuses fo office automation, the question item on the complaint symptom of health problem attendant upon the treatment of VDT that Kim(1991) developed and on CMI health problem and the question items on the fatigue degree due to industry were used by previous examination to 25 persons. Collected data were analyzed with the statistical method such as percentage, arithmetic mean, Person correlation coeffient, Kai square verfication, t-test, ANOVA, etc. by using SPSS/PC+ program, and the result is as follows : 1. The self-consciousness symptom that the clerical workers complained of most frequetly appeared high in 'My eyes are tired'(99.4%), 'I feel fatigue and weariness'(99.4%), 'I feel that my head is heavy5(90.0%), 'eyesight fell'(88.8%), 'I have a stiff neck'(88.8%), 'I fell pain in the shoulder'(85.0%), 'I feel cold and painful in the eyes'(76.9%), 'I feel the dry sense of eyeball'(76.2%), 'My nerves are edgy, and I an fretful, (75.6%), 'I feel pain in the waist'(73.2%) and 'I fell pain in the back'(72.8%). It emerged that the subject use the apparatuses for office automation complained of self-consciousness symptoms related to visual symptoms and musculoskeletal symptoms. 2. As for the general feature of examination subjects, the result to see the distribution by classifying into sex, age, school career, use career of apparatuses for office automation, skillfulness degree of the use of apparatus for office automation, use hours of the apparatuses for office automation per 1 day, type of business of the apparatus for office automation, rest hours during the use of apparatus for office automation, satifaction degree of business of office automation, and work circumstance, etc. emerged as follows : As for the sex of subjects, the distribution showed that men were 58.8% and women were 41.3%, Age was average 26.9. As the distribution of school career, the distribution showed that4below the graduation of high school' was 58.8%, 'graduation from junior college-university' was 35.0%, and 'over graduate school' was 6.3%. In the question to ask the existence or non-existence of experience of health consultation in connection with the work of office automation, the response that I had the consultation exprience and I feel the necessity emergerd as 90.1% And, the case that the subject who didn't wear the glasses or lens before using the OA apparatus wear glasses or lens after using OA apparatus emerged as 28.3% of whole. As for the existence or non-existence of use career of OA apparatus, the case under 3 years was highest as 52. 7%. As for the skillfulnness degree about the use of apparatus for office automation, most of them are skillful with the fact that 'common' was 44.4%, 'skill' was 42.5%, and 'unskillful' was 13.1% As for the use average hours of the apparatus for office automation per 1 day, the distribution showed that the case under 3-6 hours was 33.1%, the case under 6-9 hours was 28.1%, the case under 3 hours was 30.6%, and the case over 9 hours was 8.1% Main OA business and the use hours for 1 day showed in the order of keeping and retrieval, business of information transmission(162min), business of information transmission(79.3 min), business of document framing(55.5 min), and business of duplication and printing(25.4min). as for the rest during the use of apparatus for affice automation, that I take rest occasion demands the major portion, but that I take after completing the work emerged as 33.8%. Though the subiness gets to be convenient by the use of the apparatus for of office automation, respondents who showed the dissatisfaction about the present OA business emergd high as 78.1%. The work circumstances of each office was good with the fact that the temperature of office was 21.8, noise was average 42.7db, and the illumination was average 364.4 lx, in the light of ANSi/HFS 100 Standard. 3. Sight syptom, musculoskeletal symptom, skin and other symptoms showed the significant difference according to the extent of skillfulness of the apparatus for office automation. All the symptoms exept skin symptom showed the difference according to the use hours of the apparatus for office automation. All the question items exept the sytoms of digestive organs and the rest hours during the apparatus for office automation showed the signicant difference. The question item which showed the signicant difference from the satisfaction degree of present OA business showed the significant difference from all the question item classified into 6 groups. But, age and school career didn't significant difference from the complaint of any self-consciousness symptoms.