• Nuclear Engineering and Technology
• /
• 제55권10호
• /
• pp.3700-3708
• /
• 2023

The stochastic origin ensembles method with resolution recovery (SOE-RR) has been proposed to reconstruct proton-induced prompt gammas (PGs), and the reconstructed PG image was used for range verification. However, due to low detection efficiency, the number of valid events is low. Such a low-count condition can degrade the accuracy of the SOE-RR method for proton range verification. In this study, we proposed two strategies to improve the reconstruction of the SOE-RR algorithm for low-count PG imaging. We also studied the number of iterations and repetitions required to achieve reliable range verification. We simulated a proton beam (10⁸ protons) irradiated on a water phantom and used a two-layer Compton camera to detect 4.44-MeV PGs. Our simulated results show that combining the SOE-RR algorithm with restricted volume (SOE-RR-RV) can reduce the error of the estimation of the Bragg peak position from 5.0 mm to 2.5 mm. We also found that the SOE-RR-RV algorithm initialized using a back-projection image could improve the convergence rate while maintaining accurate range verification. Finally, we observed that the improved SOE-RR algorithm set for 60,000 iterations and 25 repetitions could provide reliable PG images. Based on the proposed reconstruction strategies, the SOE-RR algorithm has the potential to achieve a positioning error of 2.5 mm for low-count PG imaging.

• 한국환경보건학회지
• /
• 제20권1호
• /
• pp.54-61
• /
• 1994

This study was carried out to investigate the degree of contamination in private-drinking water supply (PDWS) and simple-piped water supply (SPWS), and to compare of water quality between them for 3 years from 1990 to 1992. The results of the study were as follows: 1. Private-drinking water supply (PDWS) (1) Field-Site (ㄱ) The items which were very significantly over the criteria (p<0.01), were temp., pH, NO-N, standard plate count (S.P.C.) and Coliform. (ㄴ) No. of households which were over the criteria, were 11.2~51.7% in temp., pH, NH$_3$-N and NO$_2$-N, and 83.1~93.3% in NO-N, S.P.C. and Coliform. (2) Moutain-Site (ㄱ) The items which were over the criteria, were NO$_2$-N (p<0.05), S.P.C. (p<0.01) and Coliform (p<0.01). (ㄴ) No. of households which were over the criteria, were 33.6 ~ 75.6% in NO$_2$-N, S.P.C. and Coliform. (3) No. of households which were fit to the criteria of all items, were 9.0% in field-site and 14.1% in mountain-site. 2. Simple-piped water supply (SPWS) (1) The items which were very significantly over the critera (p<0.01), were standard plate count (S.P.C.) and Coliform. (2) The water qualities of adjacent and remote samples were better than those of source samples. (3) Residual chloride was not detected in any sample. In conclusion, rural community requires to be continually performed the policy of safety drinking water supply, and to be devised an epoch-making counterplan for the level-up of simple-piped water supply (SPWS), espically on the method of disinfection.

• 한국산학기술학회논문지
• /
• 제11권11호
• /
• pp.4404-4410
• /
• 2010

본 연구의 목적은 홍삼 분말(0, 5, 10 %), 물(12, 16, 20 %), 설탕(4, 8, 12 %)의 첨가량을 달리하여 최적의 배합비를 찾기위하여 실시하였다. 인절미 제조에 있어서 수분 첨가량이 증가할수록 생균수는 증가하였다. 홍삼가루 첨가에 따른 생균수는 5% 첨가군에서는 유의적인 차이가 없었지만 10% 첨가군에서는 생균수가 감소하였다. 홍삼 첨가량에 따른 굳기의 변화는 홍삼 무첨가군은 수분첨가량 20%를 제외한 실험군에서 24 hr이후에 급격한 증가를 나타내었다. 그러나 홍삼 5% 첨가군에서는 수분 및 설탕 첨가량에 상관없이 굳기의 변화가 거의 나타나지 않았다. 또한 홍삼 10% 첨가군에서도 수분 첨가량 12% 이외에는 굳기의 변화가 거의 나타나지 않았다. 관능검사에서 홍삼 첨가 10%군은 홍삼 특유의 향미와 맛이 너무 강한 것으로 나타났으나, 홍삼 첨가 5%군은 향, 맛, 색이 적당한 것으로 나타났다. 생균수 측정, 조직감 측정과 관능검사의 결과에서 홍삼인절미의 최적의 배합비는 찹쌀가루에 대해 홍삼가루, 수분, 설탕이 각각 5, 16, 8%로 나타났으며 홍삼가루 첨가는 인절미의 저장성 향상효과가 있었다.

• 한국식품과학회지
• /
• 제31권2호
• /
• pp.361-367
• /
• 1999

항산화작용 및 항균작용이 있다고 알려져 있는 녹차 물추출물을 이용하여 조미오징어의 품질을 개선하기 위하여 분무하여 수분함량을 조정한 후 $30^{\circ}C$에서 보관하면서 저장중 갈색도의 변화를 측정하였다. 갈색도의 측정으로는 물추출색소, 5% KOH-methanol 추출색소, 색차계 등의 방법을 사용하였다. 물추출색소 및 5% KOH-methanol 추출색소를 이용하여 측정하였을 경우 처리구간의 높은 상관관계를 나타내어 적절한 갈색도 측정방법으로 생각되었다. 녹차의 물추출물을 분무한 처리구의 경우 저장기간에 따라 TBA가의 변화속도가 대조구보다 다소 느리게 측정되었으며 총미생물수도 낮게 측정되어 조미오징어 제조시에도 항산화작용 및 항균작용이 존재함을 알 수 있었다. 녹차 물추출물을 분무하여 조미오징어를 제조할 경우 수분함량을 다소 높여 조직감 개선에 기여할 수 있을 것으로 생각되었으며 갈변도 억제하므로 품질개선에 유효함을 알 수 있었다.

• 핵의학기술
• /
• 제16권1호
• /
• pp.86-90
• /
• 2012

Rb-82를 이용한 PET 검사는 심근 관류의 임상적 평가에 중요한 역할을 한다고 알려져 있다. 그러나 PET/CT의 dead time 때문에 count value와 방사능농도 사이의 직선성이 유지되지 않는다면 데이터를 획득할 때 좌심실 입력 함수가 과대평가되어 심근관류가 과대평가될 수 있다. 본 연구에서는 리스트 모드에서 획득한 PET data에서 방사능농도에 따른 count value의 직선성을 평가하였다. Biograph 40 True Point PET/CT를 이용하여 직경 12 cm, 길이 10.5 cm의 cylindrical phantom에 F-18 333 MBq과 물 800 mL를 채우고 7반감기동안 10min frame/bed로 리스트 모드를 이용하여 획득하였다. Raw data는 OSEM (order: 4, subsets: 8)과 FBP (Gaussian filter FWHM 5 mm) 알고리즘을 이용하여 재구성하였다. Sinogram 정보에서 prompt counts, net true counts, random counts를 측정하였다. 재구성 된 phantom 영상에 ROI를 설정하여 총 계수와 background를 측정하고 background correction을 사용하여 count value를 측정하여 직선성을 평가하였다. 리스트 모드를 이용하여 sinogram에서 측정된 prompt counts는 방사능농도에 비례하여 증가하였다. 낮은 방사능농도에서 net true counts와 random counts는 방사능농도에 따라 증가하였다. 높은 방사능농도에서는 net true counts의 증가율이 점차 감소되었고, 반면에 random counts의 증가율은 증가하였다. 그리고 OSEM과 FBP 알고리즘으로 재구성된 영상에서 측정한 count value의 차이는 없었고 방사능농도에 비례하여 count value가 증가하고 직선성이 유지되었다. Biograph 40 True Point PET/CT scanner는 재구성된 영상에서 낮은 방사능농도뿐만 아니라 높은 방사능농도(~416.25 kBq/mL)에서도 측정 된 count value와 방사능농도 사이의 직선성이 유지되는 것을 보여주었다. 따라서 실험에서 사용한 PET/CT scanner는 Rb-82, N-13, O-15, F-18을 이용한 heart dynamic PET study에서데이터의 정량적 분석에 유용할 것으로 판단된다.

• 동아시아식생활학회지
• /
• 제23권3호
• /
• pp.332-340
• /
• 2013

The aim of this study was to investigate the quality characteristics of makgeolli that was produced by using different percentages (control, 3%, 5%, 7%, 9% by rice weight) of Angelica gigas Nakai water extracts during fermentation at $25^{\circ}C$ for 7 days. Yeast cell count in makgeolli steadily increased and showed the highest value at day 4 of fermentation, since then, the count decreased consistently. The final alcohol contents were higher than 15% in all samples. Soluble contents and antioxidation activity were significantly increased in percentage as Angelica water extracts increased (p<0.05). As the amount of Angelica water extracts increased, total polyphenol contents increased as well. Soluble contents and total polyphenol contents were increased according to the fermentation period. Total acidity increased up to day 3, but slowly decreased afterwards. However, the pH rapidly decreased by day 3, but then increased steadily. Reducing sugar amount was increased sharply by day 2 of fermentation and then, diminished gradually. Hunter's color value was not significantly different among samples however, they were significantly different between day 2 samples of fermentation and day 3 or more samples (p<0.05). In sensory evaluations, the sample produced using 5% Angelica water extracts received the highest score in herbal flavor, herbal taste, sourness, sweetness, and overall acceptance. Makgeolli using Angelica gigas Nakai water extracts showed excellent characteristics in antioxidative activity and higher total polyphenol content. Makgeolli produced using 5% Angelica water extracts received the highest score in sensory evaluation. Therefore, makgeolli produced using 5% Angelica water extracts was considered to be the most suitable for manufacturing makgeolli.

• 핵의학기술
• /
• 제28권1호
• /
• pp.57-69
• /
• 2024

Purpose: Quantitative analysis through count measurement in nuclear medicine planar images is limited by analysis techniques that are useful for obtaining various clinical information or by organ overlap or artifacts in actual clinical practice. On the other hand, the use of SPECT tomography images is quantitative analysis using volume rather than planar, which is not only free from problems such as projection overlap, but also has excellent quantitative accuracy. In the use of developing SPECT quantitative analysis technology, this study aims to compare the accuracy of quantitative analysis between ROI of the conventional planar images and VOI of the SPECT tomographic images in evaluating the count change happened by the volume change of the source. Materials and Methods: A ^99mTcO₄^- source(200.17 MBq) was filled with sterilized water in the syringe to create a phantom with an inner diameter volume of 60 cc, and a planar image and a SPECT image were obtained by reducing the volume by 15 cc (25%) respectively. ROI and VOI(threshold: 1~45%, 5% interval) were set for each image obtained to estimate true count and measure the total count, and compared with the preseted volumetric change rate(%). Results: When volume changes of 25%, 50%, and 75% occurred in the initial volume of 60 cc(100%) of the phantom, the average count changes of the measured planar image were 26.8%, 53.2%, 77.5%, and the average count changes of the SPECT image were 24.4%, 50.9%, and 76.8%. In this case, the VOI size(cm³) set showed an average change rate of 25.4%, 51.1%, and 76.6%. The highest threshold value for the accuracy of radioactive concentration by VOI size (average error -1.03%) was 35%, and the VOI size of the same threshold had an error of -17.1% on average compared to the actual volume. Conclusion: On average, the count-based volumetric change rate in nuclear medicine images was able to track changes more accurately using VOI than ROI, but there was no significant difference with relatively similar value. However, the accuracy of radioactive concentration according to individual VOI sizes did not match, but it is considered that a relatively accurate quantitative analysis can be expected when the size of VOI is set smaller than the actual volume.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2005년도 국제학술대회
• /
• pp.381-385
• /
• 2005

Characterization of particle behavior is becoming more important in performance evaluation of water treatment system as well as in operation of the system because conventional parameter, turbidity has lack of explaining ability on small sized microorganisms such like Cryptosporidium etc. Accordingly, particle counter has been introduced in evaluation and operation of the treatment system. However researches on the relationship between turbidity, particle count and/or different sand/anthracite sizes have not been concurrent. Therefore in this study, the relationship was investigated to improve performance evaluation of sand filter so as to help choosing sand/anthracite effective size as a design parameter of water treatment facility. According to the results, too small or too large effective size media filter reached to turbidity limit(0.1 NTU)earlier. However, because shallow sand layer may cause early breakthrough, the depth of sand layer should be provided enough in order to compromise water quality and productivity.

• Applied Biological Chemistry
• /
• 제22권3호
• /
• pp.142-144
• /
• 1979

경기도(京畿道) 용인군(龍仁郡)과 화성군(華城郡)의 농촌지역(農村地域)에서 음료수(飮料水)를 취(取)하여 세균검사(細菌檢査)를 한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 총생균수는 3지역의 시료만 100/ml이하였으며 $1{\times}10^4/ml$ 이상은 6지역이었으며 최고 $1{\times}10^5/ml$로 나타났다. 2. Faecal Streptococcus는 용인군(龍仁郡)의 4개 지역의 시료에서 검출(檢出)되었다. 3. 음료(飮料) 적합여부(適合如否)를 국립보건 연구원의 표준비교에 의하여 판정한 결과 할 지역의 시료를 제외한 모두가 음료(飮料) 부적(不適)내지 음료적합여부(飮料適合如否)가 의심스러운 것으로 밝혀졌다.

• Clinical and Experimental Reproductive Medicine
• /
• 제50권1호
• /
• pp.19-25
• /
• 2023

Objective: Sleep deprivation (SD) is a common problem in today's stressful lifestyle and have physiological consequences, including reproductive dysfunction and infertility. As an antioxidant, olive oil may be effective in reducing testicular and spermatological damage by decreasing the production of free radicals. Methods: This study investigated the effects of olive oil on sperm quality and testicular structure using stereological methods to assess rats with SD. Results: When comparing SD group to grid floor+distilled water (GR) group, we found that the sperm count and motility, as well as the percentage of slow progressive sperm was significantly lower in SD group (p<0.05), but the percentage of immotile sperm was higher (p<0.01). However, no improvement was observed in sperm count or motility after concomitant treatment of SD group with olive oil. Stereological examinations revealed no significant change in the total volumes of the seminiferous tubules, interstitial tissue, and germinal epithelium in the study groups. Conversely, the total number of testicular cell types was significantly lower in SD group than in GR group. Although the total number of Sertoli and Leydig cells was significantly higher in the S +olive oil group than in the untreated SD group, no significant difference in the total number of other testicular cell types was observed between the two groups. Conclusion: SD potentially induced structural changes in testis that affected sperm count and motility. However, olive oil only improved the total number of Sertoli and Leydig cells in the animals with SD and did not improve sperm count and motility.