• Health Policy and Management
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• v.5 no.1
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• pp.59-79
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• 1995

This study intended to grasp the results of performance of school health policy and to provide information for the future policy performance in Korea. As the objects of the study we chose the secondary school(142 middle schools, 111 high schools) in Pusan, 1993. The contents of the study were about school health service and school health education. For the study we collected datum and took statistics through the existing theses, books, various statistics, and interviews with the persons concerned. Therefore the method of the study was basically emperical and demonstrative. The results of the study can be presented as follows : 1. the results of performance of health service proved to be 5.40% for vaccination against hepatitis B, 5.26% for typhoid fever, 6.65% for EH fever, and 9.84% for influenza in middle schools, In high schools' 5.76% for vaccination against hepatitis B, 0.03% for typhoid fever, 0.25 for EH fever, and 0.86% for influenza. 2. The results of policy performance of health education were found out 64.08% in middle schools, and 17.12% in high schools. 3. The factors which affected the results of performance of health service turned out 1) the improper standard of policy performace that applicants should pay their own expenses. 2) the lack of performer's will to carry out the policy owing to the improper standard. 3) the shortage of interorganizational enforcement activities and communications which influence the will of performance. 4. The affecting factors to the will of performance of health education proved to be 1) the improper standard that nurse-teachers can teach students in the classroom in case of need. 2) the lack of nurse-teachers due to the above inappropriate standard. 3) the lack of enforcement activities of supervising organs which employ and direct nurse-teachers. 4) the lack of activities of organs which should communicate one another and allot nurse-teachers of public schools without fail.

• Economic and Environmental Geology
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• v.55 no.2
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• pp.127-135
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• 2022

Excessive presence of As level in groundwater is a major health problem worldwide. In the Red River Delta in Vietnam, several million residents possess a high risk of chronic As poisoning. The As releases into groundwater caused by natural process through microbially-driven reductive dissolution of Fe (III) oxides. It has been extracted by Red River residents using private tube wells for drinking and daily purposes because of their unawareness of the contamination. This long-term consumption of As-contaminated groundwater could lead to various health problems. Therefore, a predictive model would be useful to expose contamination risks of the wells in the Red River Delta Vietnam area. This study used four machine learning algorithms to predict the As probability of study sites in Red River Delta, Vietnam. The GBM was the best performing model with the accuracy, precision, sensitivity, and specificity of 98.7%, 100%, 95.2%, and 100%, respectively. In addition, it resulted the highest AUC of 92% and 96% for the PRC and ROC curves, with Eh and Fe as the most important variables. The partial dependence plot of As concentration on the model parameters showed that the probability of high level of As is related to the low number of wells' depth, Eh, and SO₄, along with high PO₄^3- and NH₄⁺. This condition triggers the reductive dissolution of iron phases, thus releasing As into groundwater.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.877-887
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• 1994

Cu-Ni-Si-P alloys have been studied in order to develop connector material which has a favorable combination of strength, electrical conductivity, elastic limit, thermal softening resistence and bend formability. Three kinds of trial alloys with various nickel and silicon content were melted and cast, hot rolled at about $900^{\circ}C$ and cold rolled. Mechanical properties and electrical conductivities of these alloys annealed at $450^{\circ}C$, $500^{\circ}C$ and $550^{\circ}C$ were investigated. An alloy with the composition of Cu-2.7%Ni-0.53%Si-O.O29%P, which shows a favorable combination of high strength and high electrical conductivity, has been developed. Various characteristics of the alloy 1 connector material were evaluated and compared with phospher bronze(C521OR-H) and brass(C26OOR-EH) connector material.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.736-742
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• 2003

This paper presents the propagation path loss in a tunnel which is a kinds of underground environments. To predict propagation path loss more accurately, we choose a straight tunnel with rectangular cross-section. The simulated receiver powers that are using a hybrid waveguide model and a Ray-Tracing method, are compared with the measured ones as a function of distance between TX and RX antennas in tunnel. The attenuation value of regression analysis for measured power in the tunnel is 0.0238dB/m which is similar to the one of the EH1.2 mode, 0.0246dB/m in hybrid waveguide model. By comparing simulation with measurement in tunnels, it has been shown that the measured values are approximate to the simulated results of ray-tracing model. In the analysis of wide-band channel characteristics of the tunnel, the more the distance between TX and RX antennas in tunnel increases, RMS delay spread increases and coherence bandwidth decreases.

• Natural Product Sciences
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• v.21 no.1
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• pp.6-13
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• 2015

Phytochemical investigation of the aerial components of Ducrosia ismaelis Asch. led to the isolation of six known compounds, psoralen (1), isopsoralen (2), cnidioside A (3), (-)-syringaresinol-O-${\beta}$-D-glucopyranoside (4), (E)-plicatin B (5), trilinolein (6). The chemical structures of these compounds were elucidated from spectroscopic data and by comparison of these data with previously published results. The antioxidant, anti-osteoporotic and cardiovascular related activities of the isolated compounds were assessed using oxygen radical absorbance capacity (ORAC), reducing capacity, tartrate-resistant acid phosphatase (TRAP), and soluble epoxide hydrolase (sEH) inhibitory activity assays. Compounds (3-5) showed potent peroxyl radical-scavenging capacities with ORAC values of $11.06{\pm}0.39$, $7.98{\pm}0.10$, and $13.99{\pm}0.06$ Trolox equivalent (TE) at concentrations of $10{\mu}M$, respectively. Only compounds 4 and 5 was able to significantly reduce $Cu^{2+}$ ions, with a reduction value of $9.06{\pm}0.32$ and $4.61{\pm}0.00{\mu}M$ Trolox Equivalent (TE) at a concentration of $10{\mu}M$. Compound 5 at $10{\mu}M$ exhibited a potent inhibitory effect on osteoclastic TRAP activity with a TRAP value of $86.05{\pm}6.55%$ of the control. Compounds 1, 3 and 5 potently inhibited sEH activity with $IC_{50}$ values of 41.6 4.9, 16.0 1.1, and 49.0 $5.7{\mu}M$, respectively.

• Resources Recycling
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• v.13 no.1
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• pp.22-27
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• 2004

Purification on the leaching solution of the crude zinc oxide obtained by the reduction of EAF dust has been carried out. Pb and Cd ions in the leaching solution were precipitated and removed from the solution by the addition of zinc metal powder. The purification condition for electrowinning to obtain the high purity zinc metal was investigated by analyzing the effects of Pb and Cd ion concentrations on the contents of impurities in the recovered zinc metal. The 3 N purity zinc metal was obtained at the electrolysis condition of the concentrations of Pb less than 2 ppm and Cd less than 0.1 ppm in the purified solution. For this purification, the amounts of zinc metal powder more than 8.5 g/l should be added in the crude zinc oxide leached solution.

• Journal of Soil and Groundwater Environment
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• v.16 no.6
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• pp.133-142
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• 2011

A total of 247 samples were collected from groundwater being used for drinking-water supply, and hydrogeochemistry and radionuclide analysis were performed. In-situ analysis of groundwaters resulted in ranges of $13.7{\sim}25.1^{\circ}C$ for temperature, 5.9~8.5 for pH, 33~591 mV for Eh, $66{\sim}820{\mu}S/cm$ for EC, and 0.2~9.4 mg/L for DO. Major cation and anion concentrations of groundwaters were in ranges of 0.5~227.6 for Na, 1.0~279.3 for Ca, 0.0~9.3 for K, 0.1~100.1 for Mg, 0.0~3.3 for F, 0.9~779.1 for Cl, 0.3~120.4 for $SO_4$, 0.0~27.4 for $NO_3$-N, and 6~372 mg/L for $HCO_3$. Uranium-238 and radon-222 concentrations were detected in ranges of N.D-$131.1{\mu}g/L$ and 18-15,953 pCi/L, respectively. In case of some groundwaters exceeding USEPA MCL level ($30{\mu}g/L$) for uranium concentration, their pH ranged from 6.8 to 8.0 and Eh showed a relatively low value(86~199 mV) compared to other areas. Most groundwaters belonged to Ca-(Na)-$HCO_3$ type, and groundwaters of metamorphic rock exhibited the highest concentration of Na, Mg, Ca, Cl, $NO_3$-N, U, and those of plutonic rock showed the highest concentration of $HCO_3$, and Rn. Uranium and fluoride from granite areas did not show any correlation. However, uranium and bicarbonate displayed a positive relation of some areas in plutonic rocks($R^2$=0.3896).

• Economic and Environmental Geology
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• v.29 no.3
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• pp.305-313
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• 1996

In order to investigate the extent and degree of Cd, Cu, Pb and Zn contamination affected by mining activities of the Dalsung Cu~W mine, sampling of stream sediments and waters has been undertaken up to 1.5 km downstream from the mine at 50~150 meter intervals. Analysis of the samples was carried out using ICP-AES for Cd, Cu, Pb and Zn. Physical and chemical properties of sediments (pH, organic matter contents, cation exchange capacity) and waters (pH, Eh and temperature) were also measured. The properties of the sediment samples were characterized by low pH (3.0~5.5), low organic matter contents (2~5%) and a moderate degree of cation exchange capacity (7~15 meq/100 g) with a high proportion of sand fraction. The pH values of water samples ranged from 3.0 to 5.0 and the Eh levels were in the range of 350~530 mV. Concentrations of Cd, Cu, Pb and Zn in the sediments averaged 3.2 mg/kg, 1,390 mg/kg, 451 mg/kg and 262 mg/kg with the range of 0.6~11.4 mg/kg, 15~3,800 mg/kg, 14~1,330 mg/kg and 63~1,060 mg/kg, respectively. Significant levels of the heavy metals were also found in the water samples with the range of $10{\sim}170{\mu}gCd/l$, $300{\sim}41,600{\mu}gCu/l$, $10{\sim}80{\mu}gPb/l$ and $700{\sim}15,400{\mu}gZn/l$. These elevated concentrations in the sediments and waters may be caused by the weathering of mine waste materials and their high solubilities under acidic and/or oxidizing conditions. Although metal concentrations in the samples decrease with the distance from the mine, heavy metal contamination of sediments and waters were also found at the 1.5 km downstream due to the mobile conditions of the heavy metals, with particular reference to Cd and Zn in stream waters.

• Smart Media Journal
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• v.8 no.2
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• pp.21-28
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• 2019

Recent research on energy harvesting wireless sensor networks focuses on the development of techniques to solve the limited energy resource problem and to extend the whole network life efficiently. Energy harvesting technology can increase the lifetime of a network, but data transmission becomes unavailable when it harvests energy from radio frequency, resulting longer network delay with respect to the increased time in energy harvesting. Therefore, building energy harvesting wireless sensor network should consider the possible network delay as well as the network lifetime problem. In this paper, we propose a new MAC protocol that minimizes end-to-end network delay by adjusting the data transmission time for a packet based on estimating the energy for data transmission along with the amount of traffic flowing into the network and harvested energy. For this goal, it engineers an energy management mechanism that adjusts the sleep time of the network by measuring energy harvesting time. In addition, with simulation results it shows that the proposed MAC protocol improves the performance in terms of energy consumption and end-to-end delay, compared to the existing MAC protocols.

• Journal of Forest and Environmental Science
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• v.39 no.1
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• pp.27-39
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• 2023

Twenty-five Eucalyptus clones (14 E. camaldulensis - EC and 11 interspecific eucalypt hybrid clones - EH) grown in three contrasting sites were evaluated for the growth and few wood traits at 4 years of age. The stability, genotype-site interaction and suitability of these clones for pulp and solid wood industry sectors were studied. Growth of eucalypt clones was significantly higher at site 1 with higher rainfall, but wood density did not differ significantly from lower rainfall sites. Kraft pulp yield (KPY) decreased from sites 1 to 3 based on moisture availability, but not between two groups of clones. Volumetric shrinkage (VS) was significantly higher in EC clones at site 3 with lowest rainfall, but there was no specific trend at other two sites with maximum (site 1) and intermediate (site 2) rainfall. The mechanical traits modulus of rupture (MOR) and modulus of elasticity (MOE) were at par in sites 1 and 2, but significantly lower at the driest site 3. The growth rate had a significant positive correlation with KPY, MOR and MOE and a negative correlation with VS, but no significant impact on wood density in both groups of clones. Genotype×environment interaction (G×E) was evident in most traits due to the difference in response of clones to moisture availability. Since wood density was negatively correlated to KPY, it has to be kept at an optimum level for the profitability of pulp industry. There was no significant difference between EC and EH clones for most traits except VS at site 3. Stability of clones varied across sites in different traits, and hence clones may be selected for deployment at each site by screening for growth, followed by wood density, considering the relationship of growth and density with other traits required by pulp and solid wood industry sectors.