• Nuclear Engineering and Technology
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• 제30권5호
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• pp.452-461
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• 1998

The pin power distribution is determined by analyzing the rotational gamma scanning data for 36 element fuel bundle of HANARO. A fission monitor of Nb$^{95}$ is chosen by considering the criteria of the half-life, fission yield, emitting ${\gamma}$-ray energy and probability. The ${\gamma}$-ray spectra were measured in Korea Atomic Energy Research Institute(KAERI) by using a HPGe detector and by rotating the fuel bundle at steps of 10$^{\circ}$. The counting rates of Nb$^{95}$ 766 keV ${\gamma}$-rays are determined by analyzing the full absorption peak in the spectra. A 36$\times$36 response matrix is obtained from calculating the contribution of each rod at every scanning angle by assuming 2-dimensional and parallel beam approximations for the measuring geometry. In terms of the measured counting rates and the calculated response matrix, an inverse problem is set up for the unknown distribution of activity concentrations of pins. To select a suitable solving method, the performances of three direct methods and the iterative least-square method are tested by solving simulation examples. The final solution is obtained by using the iterative least-square method that shows a good stability. The influences of detection error, step size of rotation and the collimator width are discussed on the accuracy of the numerical solution. Hence an improvement in the accuracy of the solution is proposed by reducing the collimator width of the scanning arrangement.

• 대한안전경영과학회지
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• 제19권2호
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• pp.95-100
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• 2017

In this study, the bacterial contamination level of equipments and devices in the nuclear medicine department of a university hospital was investigated. CNS was detected from the sample collected from the door opening button of the nuclear medicine department. Bacillus sp. was detected from the table and CNS with Bacillus sp. were detected from the control button at the PET-CT room no.1. Also, CNS was detected from the table and the control button at the PET-CT room no.2. In the distribution room no.1, CNS and Bacillus sp. were detected while CNS being detected from the distribution room no.2 and CNS with Bacillus sp. being detected from the distribution room no.3. In the injection room, Enterrococcus faecium and Pontoea sp. were detected. On the table of the ecsomatics room, Pontoea sp. was detected. Bacillus sp. was detected from the inside of the syringe Pb shield and CNS was detected from the outside. Enterrococcus faecium was detected from the Gamma camera table and Bacillus sp. was detected from the door grip. On the chair at the patient waiting room, Pseudomonas aeruginosa abd Bacillus sp. were detected. Therefore, it was understood that infection should be prevented by securely sterilizing examination devices after each examination, maintaining cleanliness by regular sterilization of waiting chairs and such objects with a number of direct contacts with patients, and infection education for the features of nuclear department.

• 한국위험물학회지
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• 제6권2호
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• pp.95-104
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• 2018

Gas-liquid bubble column reactors are extensively used in industrial processes. A detailed knowledge of bubble size distribution is needed for determining the mass transfer in gas-liquid film. Experimental data on bubble size distribution and liquid-side mass transfer coefficient($k_L$) were used to calculate the estimated time to saturation in bubble column reactor. Also, the gas flux was evaluated to the liquid-side mass transfer coefficient($k_L$) and solubility data for hydrogen sulfide($H_2S$) and chlorine($Cl_2$) absorption into water. Simulation results show that $H_2S$ absorption time to 50 % of saturation concentrations are 611 sec and 1,329 sec when bubble diameters are 0.5 mm and 4.5 mm, while absorbing 1 % $H_2S$ gas. In case of $Cl_2$, absorption time range 657 to 1,400 sec when bubble size range 0.5 mm to 4.5 mm, while absorbing 1 % $Cl_2$ gas. Calculated simulation results can be used in the design of emergency relief bubble reactors.

• 한국재료학회지
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• 제31권1호
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• pp.1-7
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• 2021

The characteristics and morphology of precipitated calcium carbonate (PCC) particles produced by carbonation process with various experimental conditions are investigated in this study. The crystal structures of PCC formed by carbonation process are calcite and aragonite. The crystal structure of PCC particles synthesized without adipic acid additive is calcite only, regardless of the reaction temperature. Needle-like shape aragonite phase started to form at reactor temperature of 80℃ with the adipic acid additive. Particle size of the single phase calcite PCC synthesized without adipic acid additive is about 1 ~ 3 ㎛, with homogenous distribution. The aragonite PCC also shows uniform size distribution. The reaction temperature and concentration of adipic acid additive do not show any significant effects on the particle size distribution. Aragonite phase grown to a large aspect ratio of needle-like shape showed relatively improved whiteness. The measured whiteness value of single calcite phase is about 95.95, while that of the mixture of calcite and aragonite is about 99.11.

• 유통과학연구
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• 제22권6호
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• pp.95-106
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• 2024

Purpose: This study investigates the complex dynamics of consumer behavior in Vietnamese banking omnichannel environments, focusing on the roles of service consistency, service transparency, flow, perceived privacy risk, and loyalty intention. Research design, data and methodology: Using a sample of 422 Vietnamese bank customers, data analysis revealed significant relationships among the variables under investigation. Results: Firstly, service consistency was found to positively influence flow experiences and negatively impact perceived privacy risk, highlighting the importance of uniform service quality across channels in enhancing consumer engagement while mitigating privacy concerns. Similarly, service transparency was positively associated with flow experiences and negatively associated with perceived privacy risk, underscoring the importance of transparent information dissemination in fostering immersive consumer experiences while alleviating privacy apprehensions. Furthermore, both flow experiences and perceived privacy risk significantly influenced loyalty intentions, indicating the pivotal roles of engaging experiences and data security in driving consumer loyalty. Additionally, mediated relationships were observed, demonstrating the interplay between service consistency, service transparency, flow, perceived privacy risk, and loyalty intention in shaping consumer behavior in omnichannel contexts. Conclusions: These findings provide valuable insights for retailers and marketers seeking to optimize consumer experiences and cultivate loyalty in omnichannel environments by prioritizing consistency, transparency, and data privacy protection.

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.95-100
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• 1993

A noise-induced transition is presented for a bistable system subjected to a multiplicative random force, which is singular at the unstable state. The stationary probability distribution is obtained from the Fokker-Planck equation and the effects of the singularity is analyzed. On the basis of noise-induced phase transition with Gaussian white noise, the relaxation time and the transition rate of the system are evaluated up to the first order correction of D. In the parameter region v < l, the transition rates decrease as the exponent v goes to 1 and as the coefficient of the linear term of the kinetic equation increases.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5861-5865
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• 2013

We investigated the distribution of HPV genotypes in Uyghur women in Xinjiang region of China, and behavioral factors which could predispose them to HPV infection. In this cross-sectional study, women aged 15-59 years were recruited by cluster sampling method in Yutian region in 2009. Liquid-based cytology samples were analyzed centrally for HPV genotype with a linear array detector. Univariate and multivariate logistic regression analyses were performed to identify behavioral risk factors for HPV infection. A total of 883 Uyghur women were recruited successfully. The prevalence of high-risk HPV and low-risk HPV were 7.25% and 1.58%, respectively; the most common HPVs were HPV16, 51, 31, 39 and 58. We found that age of first sexual intercourse was a strong predictor for HPV infection (odds ratio of 4.01 for ${\leq}15$ years versus ${\geq}25$). Having sexual partners ${\geq}3$ was the second predictor (OR 3.69, 95% CI 2.24-7.16). Cleaning the vagina after sex showed an increased risk of HPV infection (OR 2.72; 95% CI 1.98-5.13); Using the condom showed protective factors for HPV infection (OR 0.36; 95%CI0.12-0.53). HPV16, 51, 31, 39 and 58 were the priority types; the age of first sexual intercourse was identified as a major risk factor for HPV infection. Other notable risks were number of sexual partners and cleaning the vagina after sex. Changing these behavioral risk factors could help to reduce the occurrence of cervical cancer in this population.

• 경영과학
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• 제17권3호
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• pp.73-95
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• 2000

In Korea, the distribution channel for agricultural products is notorious for its complexity and ineffectiveness. In this sense, the Agricultural Cooperative has tried to clarify the distribution channel and reduce its length. However, there still exist much room for improvements. The Internet shopping mall specific for agricultural product, therefore, is drawing much attention because it can reduce the length of distribution channel drastically and improve effectiveness from the distribution perspective. To test the validity of such Internet-driven shopping mall, we gathered questionnaire data from the Internet based Hannaro Shopping Mall which is run directly by the Agricultural Cooperative. We performed experiments respectively for the two groups of operating personnel and consumers. Experimental results showed that several important factors can be identified which are significant statistically and deemed to have meaningful relationship with performance variables. Our results also showed that the Internet shopping mall has a great potential for improving the effectiveness of the distribution channel of the agricultural products.

• 대한방사선치료학회지
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• 제31권1호
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• pp.7-15
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• 2019

목 적: 본 연구에서는 lung SBRT가 적용되는 작은 계획 표적 용적(PTV)에 처방 선량이 정확히 전달되는지 실험을 통하여 알아보고자 한다. 치료계획 시스템에서 계산된 선량분포와 실험을 통하여 필름에 측정된 선량분포를 비교 분석하여 정확성을 평가해보고, 폐 실질 조직 내에서 계획 표적 용적의 margin 유용성 평가를 하고자 한다. 대상 및 방법: CT 촬영으로 얻은 Rando phantom 3D 영상의 우측 폐에 직경 2, 3, 4, 5 cm인 가상의 구 표적을 만들어 계획 표적 용적에 처방선량의 95 %가 전달될 수 있도록 6MV-FFF VMAT Arc 2개로 치료계획을 수립하였으며, Eclipse TPS와 동일한 위치에서 선량 비교하기 위해서, 필름을 가상 표적의 회전중심점에 횡단면 방향으로 삽입하고 방사선을 조사하였다. Dose profile을 Eclipse에서 획득하고, 측정값과 계산값을 비교하기 위해 Center point에서의 절대 선량값을 계산하였으며, off-axis 선량 분포를 얻어 RMSE, Coverage ratio 등 비교 인자를 통해 상대 선량 및 선량분포를 비교 분석하였다. 결 과: 직경 2, 3, 4, 5 cm 크기별로 center point에서의 %difference 값은 직경 2 cm에서 -4.65 %로 가장 차이가 큰 값을 보였고, 직경 5 cm일 때 -1.46 %로 가장 차이가 작은 값을 보였다. RMSE값은 직경 2 cm일 때 3.43으로 가장 큰 값을 보였고. 직경 5 cm일 때 2.85로써 가장 작은 값을 보였다. 표적 커버리지를 비교하기 위해 처방선량 95 %가 들어가는 용적의 길이($D_{95}$)를 구하였고, 직경 2 cm일 때, TPS와 필름에서 각각 2.02 cm, 1.86 cm로 커버리지 비율이 92 %로 나타났고 가장 큰 차이를 보였다. 또한 계획 표적 용적 100% 이내에 들어가는 평균선량($D_{mean}$)을 비교했을 때, 직경 2 cm 인 경우 측정 평균선량이 95.72 %로 가장 낮은 값을 보였다. 결 론: 본 연구에서는 실험을 통하여 작은 계획 표적 용적에 처방 선량이 충분히 전달되는지 알아보았다. 실험 결과 모든 비교 인자에서 직경 2 cm인 용적이 가장 큰 차이를 보였다. 이는 표적 용적 중심에서의 선량 감소가 주요인이라 판단된다. 따라서 선량계산 시스템에서 저밀도 조직 내의 작은 용적 치료 계획시 2 mm 이상의 마진(margin)을 더 두거나, 치료 계획 최적화(optimization)시 최대선량을 제한하지 않는 방법으로 표적 내 중심 선량을 높일 수 있을 것이라 사료된다.

• Journal of Preventive Medicine and Public Health
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• 제51권1호
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• pp.33-40
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• 2018

Objectives: The aim of this study was to determine the factors associated with the spatial distribution of the incidence of colorectal cancer (CRC) in the neighborhoods of Tehran, Iran using Bayesian spatial models. Methods: This ecological study was implemented in Tehran on the neighborhood level. Socioeconomic variables, risk factors, and health costs were extracted from the Equity Assessment Study conducted in Tehran. The data on CRC incidence were extracted from the Iranian population-based cancer registry. The $Besag-York-Molli{\acute{e}}$ (BYM) model was used to identify factors associated with the spatial distribution of CRC incidence. The software programs OpenBUGS version 3.2.3, ArcGIS 10.3, and GeoDa were used for the analysis. Results: The Moran index was statistically significant for all the variables studied (p<0.05). The BYM model showed that having a women head of household (median standardized incidence ratio [SIR], 1.63; 95% confidence interval [CI], 1.06 to 2.53), living in a rental house (median SIR, 0.82; 95% CI, 0.71 to 0.96), not consuming milk daily (median SIR, 0.71; 95% CI, 0.55 to 0.94) and having greater household health expenditures (median SIR, 1.34; 95% CI, 1.06 to 1.68) were associated with a statistically significant elevation in the SIR of CRC. The median (interquartile range) and mean (standard deviation) values of the SIR of CRC, with the inclusion of all the variables studied in the model, were 0.57 (1.01) and 1.05 (1.31), respectively. Conclusions: Inequality was found in the spatial distribution of CRC incidence in Tehran on the neighborhood level. Paying attention to this inequality and the factors associated with it may be useful for resource allocation and developing preventive strategies in at-risk areas.