• Transactions of the Korean Society of Mechanical Engineers B
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• 제22권2호
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• pp.173-183
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• 1998

An optimization procedure to find the inlet concentration profile that yields the most uniform deposition rate in a cylindrical CVD chamber has been developed. Assuming that the chemical reaction time is negligibly small, a SIMPLE based finite-volume method is adopted to solve the fully elliptic equations for momentum, temperature, and concentration. The inlet concentration profile is expressed by a linear combination of Chebyshev polynomials and the coefficients of which are determined by the local random search technique. It is shown that the present method is very effective in improving the uniformity of the deposition rate, especially when Re is high and/or the wafer is placed close to the inlet. The optimal profiles have been obtained for various Re, Gr, and geometry combinations.

• Journal of Industrial Technology
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• 제15권
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• pp.15-22
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• 1995

We have studied the generation and behavior of negative ions in silane plasmas. The negative ions were formed by homogeneous reaction in silane plasma and the behavior of negative ions were predicted by solving the model equations. The concentration profiles of negative ions were shown as a function of reactor length and time. The effects of process variables such as reactor pressure, flow rate and electrical field strengths on the behavior of negative ions were analyzed.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 한국해안해양공학회 2002년도 한국해안해양공학발표논문집 Proceedings of Coastal and Ocean Engineering in Korea
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• pp.294-297
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• 2002

ADP(Acoustic Current Profiler)는 수중에서 음파를 발사하여 해수와 함께 유동하는 부유입자에 의하여 반사되는 음향의 Doppler 효과를 이용하여 여러 개의 수층에서 유속과 유향을 측정하는 장비이다. Doppler 효과에 의한 반사음향의 주파수 천이가 부유입자의 속도에 따라 달라지는 것을 이용하여 해수의 흐름을 관측할 수 있다. (중략)

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제11권2호
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• pp.59-66
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• 2007

The oxygen distribution at steady state is analyzed mathematically in a hexagonal cylinder. The domain is penetrated by parallel cylindrical capillaries of different oxygen squirt. Asymptotic solution is used to determine the effect of axial diffusion. Oxygen concentration profiles are displayed at some positions of capillary-beds. At the venous end some tissue areas suffer from a shortage of oxygen.

• Journal of The Korean Astronomical Society
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• 제13권1호
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• pp.27-33
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• 1980

Surface density distributions for globular clusters were obtained from photoelectric surface photometry (using centered aperture photometry). These surface brightness profiles were then compared with the theoretical surface density distribution of King's model. From the comparison of the theoretical and observed surface density distributions, we determine he structural parameters of the clusters (the core radius $r_c$, the tidal cut off $r_t$, and the concentration factor C).

• Macromolecular Research
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• 제12권1호
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• pp.26-31
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• 2004

Using gravimetry, we have studied the diffusion of water into sulfonated polystyrene ionomers. Diffusion coefficients were calculated from Fick's equation. The water sorption was found to be dependent on the ion content (3.6-11 mol％) and the nature of the cation (H, Na, Li, or Zn). The sorption kinetics indicates a slight deviation from Fickian behavior. We used the analytical solution of Fick's equation to evaluate the concentration profiles, which are in good agreement with the experimental results.

• Journal of Preventive Medicine and Public Health
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• 제44권5호
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• pp.218-225
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• 2011

Objectives: This study investigated the relationship between the blood mercury concentration and cardiovascular risk factors in elderly Korean individuals living in coastal areas. Methods: The sample consisted of 477 adults (164 males, 313 females) aged 40 to 65 years who visited a Busan health promotion center from June to September in 2009. The relationship between blood mercury concentration and cardiovascular risk factors including metabolic syndrome, cholesterol profiles, blood pressure, body mass index (BMI), waist circumference and waist-to-hip ratio (WHR), was investigated. Variables related to blood mercury concentration were further evaluated using multiple regression analysis. Results: The blood mercury concentration of the study population was 7.99 (range, 7.60 to 8.40) ${\mu}g$/L. In males, the blood mercury concentration was 9.74 (8.92 to 10.63) ${\mu}g$/L, which was significantly higher than that in females (7.21, [6.80 to 7.64] ${\mu}g$/L). The blood mercury concentration of the study population was related to several cardiovascular risk factors including low-density lipoprotein (LDL) cholesterol (p=0.044), high-density lipoprotein (HDL) cholesterol (p=0.034), BMI (p = 0.006), waist circumference (p = 0.031), and WHR (p < 0.001). In males, the blood mercury concentration was significantly correlated with WHR in the multiple regression analysis. Conclusions: In males, the blood mercury concentration was related to waist-to-hip ratio, which is a central obesity index and cardiovascular risk factor. Our finding suggests that cardiovascular disease risk in males was increased by mercury exposure via an obesity-related mechanism.

• Journal of the Korean Society of Hazard Mitigation
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• 제6권1호
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• pp.83-95
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• 2006

This study aims to analysis of suspended-load concentration in related to those data by measuring vertical sediments distribution with rainfall using the ASM (Argus Surface Meter)- IV at the channel reach of a upstream and a downstream in small river. The watershed, small river basin where had taken for experimental study was selected, which is a drainage area lied at Walha in Yunkee-Gun, Chungnam Province. Measured data of suspended-load concentration consists of two groups with 2,145 data during 1hr 11min 30sec and 1,216 data during 40min 32sec for measuring time of 2 second in the study reaches at river, respectively. In order to analyze of the vertical concentration distribution, using the data sets are selected the measuring time 16 sets one of these data by random in the study reaches. As a results, the Rouse number of a measured and a calculated value show that a rang of $0.00129{\sim}0.02394$, averaged value of 0.01129 md, a rang of $0.00118{\sim}0.00822$, averaged value of 0.00436 in upstream reaches, and also a rang of $0.065115{\sim}0.065295$, averaged value of 0.06521, and a rang of $0.057315{\sim}0.059109$, averaged value of 0.05795 in downstream reaches, respectively. These difference show that measured Rouse number compared with downstream reach errors of less than in upstream reach, but between measured and calculated of the Rouse number compared with downstream reach errors of more than in upstream reach, respectively. It seems to will be included one of the occurrence errors of variable estimations when Rouse number of calculated value to be made computed by the fall velocity with a high temperature of water using equation of empirical kinematic viscosity was derived in this study.

• Journal of Environmental Health Sciences
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• 제20권4호
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• pp.80-89
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• 1994

It was reported that BCF's (Bioconcentration Factor) on Carbaryl and BPMC in concentration of 1, 2, 5 and 10 ppm, previously. Carassius auratus(goldfish) was chosen as test organism. Carbamates in fish and in test water were extracted with n-hexane and acetonitrile. GC-ECD was used to detecting and quantitating of Carbamates. Also, partition coefficients were determined with Stir flask method. To evaluate environmental toxicological profiles of tested compounds, experimental concentration were 0.05, 0.1 and 0.5 ppm in contrast to previous report. It was considered that higher BCFs of BPMC due to its higher partition coefficient compared to Carbaryl. The obtained results were as follows: 1. It was possible to determine short term BCF of Carbaryl and BPMC through relatively simple procedure in environmental concentrations. 2. BCF$_3$ of Carbaryl in concentration of 0.05, 0.1 and 0.5 ppm were 4.666 $\pm$ 0.002, 3.622 $\pm$ 0.004, 1.200 $\pm$ 0.002 and BCF$_5$ were 3.897 $\pm$ 0.005, 4.219 $\pm$ 0.017 and 1.186 $\pm$ 0.054, respectively. In the case of BPMC in same condition, BCF$_3$ were 4.077 $\pm$ 0.014, 4.900 $\pm$ 0.005, 4.750 $\pm$ 0.009 and BCF$_5$ were 3.465 $\pm$ 0.010, 4.612 $\pm$ 0.011 and 4.075 $\pm$ 0.012, respectively. 3. Carbaryl concentration in fish extract was increased as increasing test concentration, but BCF were decreased as prolonging test period, especially dropped at 0.5 ppm. 4. In the case of BPMC, BCF were decreased as increasing test concentration, but the concentration in fish extract of 3-day test group was slightly higher than that of 5-day test group. 5. Higher BPMC concentration in fish extract was due to its higher partition coefficient to compared with Carbaryl. 6. Determined logP of Carbaryl and BPMC were 2.200 and 3.180. But the calculated BCF using suggested equation was so different that predict BCF. It is suggested that BCF's of Carbamates have to be determined by experiment.

• Korean Journal of Veterinary Service
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• 제39권3호
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• pp.151-157
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• 2016

The present study was undertaken to clarify the changes in blood chemical values of indigenous Korean striped calves according to age. Blood samples were collected from 15 calves (8 females and 7 males) reared at the Gyeongsangbukdo Livestock Research Institute and the levels of various chemicals in serum were analyzed. The mean total protein, albumin and globulin concentration in calves increased from 2 weeks after birth, and the levels in females were higher than those in males at 8 weeks after birth. The mean glucose concentration increased significantly at 2 weeks after birth. The mean blood urea nitrogen concentration increased from 2 weeks after birth, whereas the mean creatinine concentration decreased significantly from 2 weeks after birth. The mean uric acid concentration increased gradually from 2 weeks after birth. The mean glutamic oxaloacetic transaminase and glutamic pyruvic transaminase concentration increased significantly from 2 weeks after birth. The mean total bilirubin concentration tended to decrease from 2 weeks after birth. The mean triglyceride, total cholesterol and high density lipoprotein cholesterol concentration increased significantly from 2 weeks after birth. In conclusion, the data obtained from this study may be valuable as a standard for interpreting results of biochemical analyses in indigenous Korean striped calves.