• 방사성폐기물학회지
• /
• 제3권3호
• /
• pp.159-165
• /
• 2005

원자력 시설의 해체 시 발생되는 다양한 종류의 폐기물 중에서 배관류를 재활용하거나 처분하기 위해서는 배관 내부의 정확한 방사선학적인 오염 특성의 평가가 선행되어야 한다. 그러나 기존의 측정법인 survey-meter를 이용한 오염도의 직접 측정은 배관 내부와 같은 국소지역의 오염 특성을 정확하게 평가할 수 없으며, 간접법을 이용한 표면오염도 측정의 경우도 시료채취의 어려움뿐만 아니라 시료채취 시 작업자의 오염 가능성이 있기 때문에 적용성에 많은 문제점이 있다. 본 연구에서는 Monte Carlo 모사기법을 이용해 직경이 작은 배관 내부의 베타선 오염도를 측정하기 위하여 플라스틱 섬광체를 모사하였으며, 모사 결과에서 베타선 에너지를 효율적으로 측정할 수 있는 최적의 플라스틱 섬광체 두께 및 형상을 도출할 수 있었다. 이 전사모사 결과를 바탕으로 섬광체의 가공 및 배관 내부에서의 검출기 이송 문제를 고려해 검출기를 제작하였으며 그 특성을 평가하였다. 그 결과 배관 내부의 오염도 측정에 적합한 검출기 성능을 확인하였고, 파이프 내부처럼 국소 지역의 방사선학적 오염 특성 평가를 위한 검출기 개발 가능성을 확인하였다.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2009년도 학술논문요약집
• /
• pp.84-85
• /
• 2009

New approaches for detecting, preventing and remedying environmental damage are important for protection of the environment. Procedures must be developed and implemented to reduce the amount of waste produced in chemical processes, to detect the presence and/or concentration of contaminants and decontaminate fouled environments. Contamination can be classified into three general types: airborne, surface and structural. The most dangerous type is airborne contamination, because of the opportunity for inhalation and ingestion. The second most dangerous type is surface contamination. Surface contamination can be transferred to workers by casual contact and if disturbed can easily be made airborne. The decontamination of the surface in the nuclear facilities has been widely studied with particular emphasis on small and large surfaces. The amount of wastes being produced during decommissioning of nuclear facilities is much higher than the total wastes cumulated during operation. And, the process of decommissioning has a strong possibility of personal's exposure and emission to environment of the radioactive contaminants, requiring through monitoring and estimation of radiation and radioactivity. So, it is important to monitor the radioactive contamination level of the nuclear facilities for the determination of the decontamination method, the establishment of the decommissioning planning, and the worker's safety. But it is very difficult to measure the surface contamination of the floor and wall in the highly contaminated facilities. In this study, the poly(styrene-ethyl acrylate) [poly(St-EA)] core-shell composite polymer for measurement of the radioactive contamination was synthesized by the method of emulsion polymerization. The morphology of the poly(St-EA) composite emulsion particle was core-shell structure, with polystyrene (PS)as the core and poly(ethyl acrylate) (PEA) as the shell. Core-shell polymers of styrene (St)/ethyl acrylate (EA) pair were prepared by sequential emulsion polymerization in the presence of sodium dodecyl sulfate (SOS) as an emulsifier using ammonium persulfate (APS) as an initiator. The polymer was made by impregnating organic scintillators, 2,5-diphenyloxazole (PPO) and 1,4-bis[5-phenyl-2-oxazol]benzene (POPOP). Related tests and analysis confirmed the success in synthesis of composite polymer. The products are characterized by IT-IR spectroscopy, TGA that were used, respectively, to show the structure, the thermal stability of the prepared polymer. Two-phase particles with a core-shell structure were obtained in experiments where the estimated glass transition temperature and the morphologies of emulsion particles. Radiation pollution level the detection about under using examined the beta rays. The morphology of the poly(St-EA) composite polymer synthesized by the method of emulsion polymerization was a core-shell structure, as shown in Fig. 1. Core-shell materials consist of a core structural domain covered by a shell domain. Clearly, the entire surface of PS core was covered by PEA. The inner region was a PS core and the outer region was a PEA shell. The particle size distribution showed similar in the range 350-360 nm.

• 폴리머
• /
• 제37권4호
• /
• pp.411-419
• /
• 2013

다양한 생체재료들이 이식용 인공장기나 의료용 장비로 폭넓게 사용되고 있으나 혈액과 접촉하는 경우가 많아짐으로써 발생되는 혈전의 문제로 인해 이식재와 혈액간의 혈액 친화성의 향상이 연구자들에게 관심의 대상이 되고 있다. 연잎의 표면구조는 항 오염 특성이라는 측면에서 많은 연구가 진행되어 왔으며, 산업적인 용도로 적용하고자 하는 주된 시도들이 있어 왔다. 대부분 주형법이나 졸-젤 방법, 층 쌓기 방법 등을 포함한 다양한 기법으로 표면처리를 함으로써 인위적인 모사가 가능해 왔다. 최근에 들어 이러한 표면의 초소수성 성질이 의료용 재료의 표면처리 기법으로써 혈관 이식재에서부터 항 박테리아용 표면에까지 널리 적용하려는 시도가 진행되고 있다. 본 리뷰논문에서는 최근 많이 사용되는 연잎 구조로의 표면처리 기법들을 중심으로 요약하였으며, 이들을 이용한 의료분야로의 적용 시도들을 정리하고자 하였다.

• 대한치과교정학회지
• /
• 제43권2호
• /
• pp.96-100
• /
• 2013

Objective: To evaluate the effects of contamination by either blood or a hemostatic agent on the shear bond strength (SBS) of orthodontic buttons. Methods: We used 45 freshly extracted, non-carious, impacted third molars that were divided into 3 groups of 15. Each tooth was etched with 37% phosphoric acid gel for 30 s. Human blood or the blood stopper agent was applied to the tooth surface in groups I and II, respectively. Group III teeth were untreated (controls). Orthodontic buttons were bonded to the teeth using light-curing composite resin. After bonding, the SBS of the button was determined using a Universal testing machine. Any adhesive remaining after debonding was assessed and scored according to the modified adhesive remnant index (ARI). ANOVA with post-hoc Tukey's test was used to determine significant differences in SBS and Fisher's exact test, to determine significant differences in ARI scores among groups. Results: ANOVA indicated a significant difference between groups (p < 0.001). The highest SBS values were measured in group III ($10.73{\pm}0.96$ MPa). The SBS values for teeth in groups I and II were significantly lower than that of group III (p < 0.001). The lowest SBS values were observed in group I teeth ($4.17{\pm}1.11$ MPa) (p < 0.001). Conclusions: Contamination of tooth surfaces with either blood or hemostatic agent significantly decreased the SBS of orthodontic buttons. When the contamination risk is high, it is recommended to use the blood stopper agent when bonding orthodontic buttons on impacted teeth.

• 분석과학
• /
• 제29권2호
• /
• pp.85-93
• /
• 2016

지문채취용 브러쉬를 이용해 사람 피부에서 지문을 채취할 경우 브러쉬로 DNA가 전이될 가능성을 연구하였다. 이때에는 지문분말을 묻힌 브러쉬와 묻히지 않은 브러쉬로 나누어 실험하였다. 살아있는 사람과 사망한 사람으로 구분하여 손가락과 손목부위를 지문채취용 브러쉬로 문지른 결과 살아있는 사람에게서보다는 사망한 사람에게서 더 많은 DNA가 브러쉬로 전이되는 것을 확인할 수 있었다. 또한 분말을 묻히지 않고 실험한 경우보다는 분말을 묻히고 실험한 경우에 더 많은 DNA가 브러쉬로 전이되는 것을 확인할 수 있었다. 브러쉬로 전이된 DNA와 채취 대상자의 프로파일을 비교한 결과 full 프로파일이 나타나는 경우는 관찰되지 않았고 partial 프로파일만이 나타났다. 이를 통해 피부 표면에 묻어있는 DNA가 브러쉬로 전이된다는 것을 알 수 있었다.

• Restorative Dentistry and Endodontics
• /
• 제17권2호
• /
• pp.383-397
• /
• 1992

The purpose of this study was to evaluate the influence of artificial saliva contamination on bonding of several dentin adhesives to dentin. Sixty - three human molar teeth extracted within a month were used. Each tooth was sectioned longitudinally in a buccolingual direction to obtain 126 specimens. These specimens were randomly divided into three groups and were treated by Scotchbond 2, Gluma and All bond. Each group was subdivided into three subgroups; normal group not contaminated with artificial saliva, contaminated with artificial saliva and dried group, and contaminated with artificial saliva and washed and dried group. Enamel/dentin bonding agent(Dental Adhesive of Scotchbond 2) was applied and light cured on the treated dentin surfaces. Thereafter P - 50 were cured on them, and specimens were stored in $37^{\circ}C$ artificial saliva for 24 hours before measuring shear bond strength. Shear bond strengths were determined using an universal testing machine with cross head speed 1mm/min and SEM examinations were conducted to evaluate the resin - dentin interface and degree of penetrating resin string into the dentinal tubules. The following results were obtained. 1. Normal groups not contaminated with artificial saliva showed greater shear bond strength than any other group contaminated with artificial saliva(P<0.01). 2. The shear bond strengths showed no significant difference between washed groups with distilled water and not washed groups after contamination with artificial saliva(P>0.05). 3. In normal groups, the shear bond strength of A group was significantly greater than in any other group(P<0.01). 4. In Sand G groups, fractures after shear bond strength tests occured adhesively on resintooth interface in all specimens. But in A groups, fracture of the normal group occured cohesively in dentin and fracture of the contaminated groups occured adhesively and cohesively. 5. On SEM examination, the number of resin strings penetrated into dentinal tubules were the greatest in normal groups, followed by, in descending order, washed groups and not washed groups after contamination with artificial saliva.

• 한국안전학회지
• /
• 제21권2호
• /
• pp.138-142
• /
• 2006

직업성 천식은 시안화물의 폭로에 의해 발생되는 것으로 알려져 있다. 남호주에 있는 가구산업에서는 일반적으로 목재판 위를 피복하기 위해 이중분사도포를 할 때 이소시안화물 도포제가 사용된다. 이 연구는 이와 관련 된 분야의 자료부족으로 관련 산업에서의 환경 및 피부와 안구폭로에 대한 모니터링을 위하여 수행되었다. 이 연구결과에 의하면 저압다량(HVLP)의 분사기 사용, 페인트 용액중의 저농도 경화제 및 전면 호흡보호구와 같은 적절한 보호구의 사용시에는 대기로부터 오염물질의 유입은 거의 없었고, 분사실 주변의 일반적인 작업범위에도 HDI 가 거의 감지되지 않았다. 페인트분사시의 일회용 장갑착용으로 피부폭로는 발견되지 않았으나, 칼라 모니터링에 의하면 장갑을 착용하지 않거나 청결하게 관리할 수 있는 공정이나 안전한 장소에 보관하지 않으면 작업장으로부터 피부폭로가 있었다. 페인트분사로부터 눈의 오염은 감지되지 않았고, 호흡기, 피부 및 안구에도 폭로되지 않았으며 유입과 가장 관련성이 있는 것은 작업형태이다.

• 한국동물위생학회지
• /
• 제45권3호
• /
• pp.191-199
• /
• 2022

We investigated the virulence genes, O-serotypes, antimicrobial resistance of pathogenic E. coli isolated from carcasses (n=455) and environmental (n=372) samples of 11 cattle and 12 pig slaughterhouses from December 2020 to December 2021. E. coli were isolated from nine carcasses (2.0%), three slaughter facilities (1.4%), two utensils (2.7%) and three abattoir workers (3.5%) from four cattle and four pig slaughterhouses. Among all isolates, 13 STEC (76.5%) were identified, followed by four EPEC (23.5%). As a result of the antibiotic susceptibility test, all isolates were resistant to at least one antimicrobial, of which 70.6% isolates showed multidrug resistance patterns. The serotypes were diverse in pigs compared to cattle, with serotypes O18, O66, O109 in cattle and O9, O76, O85, O100, O153, and O159 in pigs. In a single cattle slaughterhouse, eight STEC O66 were isolated from various types of sample (4 slaughter animal surfaces, 3 gloves, and 1 knife) with two antimicrobial resistance patterns (CHL-FIS-STR and CHL-FIS). Those two types of strain were suspected cross-contamination from utensils to slaughter animal surfaces. These results showed that pathogenic E. coli were detected in carcasses and various environmental samples in cattle and pig slaughterhouses. Nationwide monitoring and hygiene management are required to prevent cross-contamination of STEC isolate slaughterhouses.

• 한국식품위생안전성학회지
• /
• 제28권3호
• /
• pp.272-278
• /
• 2013

본 연구는 polyvinyl chroride (PVC)와 stainless steel 표면에서 E. coli O157:H7의 부착, 바이오필름형성, 온 습도에 따른 생존율을 조사하고, E. coli O157:H7이 오염된 작업대 표면에서 상추로의 교차오염도 조사를 통하여 E. coli O157:H7에 오염된 작업대가 상추의 미생물학적 안전성에 미치는 영향을 평가하고자 수행하였다. 작업대 표면 재질인 PVC와 stainless steel에 E. coli O157:H7 배양액을 1시간 노출시켰을 때, PVC의 경우, stainless steel 보다 10배 정도 부착력이 높았으나, 6시간째는 두 재질간의 차이가 없었다. 또한, E. coli O157:H7의 바이오필름 형성은 TSB > 10% 상추추출액 > 1% 상추추출액 > phosphate buffer 순이었으며, 재질별로는 PVC에서 바이오필름형성능이 높은 것으로 나타났다. 온도 $20^{\circ}C$, $30^{\circ}C$, 습도 43%, 69%, 100%에서 각각 노출 시켰을 때, E. coli O157:H7은 온도 $30^{\circ}C$, 습도 43%, 69% 조건에서 12시간 내에 약 5.0 log CFU/coupon이 감소한데 반해, 상대습도 100%에서는 농도의 큰 변화 없이 5일 이상 생존이 지속되었다. 또한, 유기물이 작업대 표면에 존재 시, E. coli O157:H7의 감소 속도가 느렸다. E. coli O157:H7에 오염된 작업대에 상추를 접촉시키고 상추의 오염도를 조사한 결과, 상추 표면에 수분이 존재할 때 오염된 작업대 표면에서 E. coli O157:H7의 이동수준이 상추에 수분이 없을 때 보다 10배 이상 증가하는 것으로 나타났다. 따라서 E. coli O157:H7에 오염된 작업대는 상추의 안전성에 직접적인 영향을 미칠 수 있어 작업 후에 세척, 소독을 통하여 위생적으로 관리하는 것이 필요하다.

• 방사선산업학회지
• /
• 제9권2호
• /
• pp.91-102
• /
• 2015

The iridium disc, generally used in industrial radiography, is examined to find the fracture morphology and fine particles remaining on the shear blank surface. Randomly selected 1,200 discs were observed under a scanning electron microscope tilted more than $45^{\circ}$. Fracture surfaces are classified into three groups: (1) surface fall-out, (2) fracture on the edge and (3) multi-step brittle fracture, which shows the mutual relationship between the fracture morphology and remaining particles. Fracture particles were removed by cleaning the discs in a ultrasonic bath with acetone and collected at the bottom. Removed number of the particles were counted for each different group of fracture surfaces. Followings are conclusions: (1) About 80.5% of discs (966/1,200), have sound plastic shear surfaces with particles remained. (2) About 2% discs accompany surface fall-out's having large particles tens of ${\mu}m$, which is stable not to be pulled out even after the considerably long time of ultrasonic cleaning. (3) About 5% discs contain the fractures on the edge and the particles are removed thoroughly within 30 minutes. (4) 234 discs out of 1,200 discs have multi-step fracture surfaces whose particles never removed in a short period of time but come out very slowly. Such a disc having multiple-step fracture is attributed to the promate cause to the 'leaker'. It is noted here that the discs having mutiple-step fractures should be treated separately with special care, and it is need to study how to treat them.