• Clean Technology
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• v.24 no.1
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• pp.77-84
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• 2018

In this study, $Li_4Ti_5O_{12}$ anode materials for lithium ion battery were synthesized by dry ball-mill method. Polyvinyl chloride (PVC) as a carbon source was added to improve electrochemical properties. When the PVC was added after $Li_4Ti_5O_{12}$ formation, the spinel structure was well synthesized and it was confirmed by X-ray diffraction (XRD) experiments. When the carbon material was added before the synthesis and the heat treatment was performed, it was confirmed that a material having a different crystal structure was synthesized even when a small amount of carbon material was added. In the case of $Li_4Ti_5O_{12}$ without the carbon material, the electrical conductivity value was about $10{\mu}S\;m^{-1}$, which was very small and similar to that of the nonconductor. As the carbon was added, the electrical conductivity was greatly improved and increased up to 10,000 times. Electrochemical impedance spectroscopy (EIS) analysis showed that the size of semicircle corresponding to the resistance decreased with the carbon addition. This indicates that the resistance inside the electrode is reduced. According to the Cyclic voltammetry (CV) analysis, the potential difference between the oxidation peak and the reduction peak was reduced with carbon addition. This means that the rate of lithium ion insertion and deinsertion was increased. $Li_4Ti_5O_{12}$ with 9.5 wt% PVC added sample showed the best properties in rate capabilities of $180mA\;h\;g^{-1}$ at 0.2 C-rate, $165mA\;h\;g^{-1}$ at 0.5 C-rate, and $95.8mA\;h\;g^{-1}$ at 5 C-rate.

• Journal of Life Science
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• v.26 no.6
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• pp.633-639
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• 2016

Biomaterials including polymer, metal, ceramic, and composite have been widely applied for medical uses as medical fibers, artificial blood vessels, artificial joints, implants, soft tissue, and plastic surgery materials owing to their physicochemical properties. However, the biocompatibility and toxicity for film- and plate-form biomaterials is difficult to measure in mammalian cells because there is no appropriate incubation system. To solve these problems, we developed a novel mammalian cell culture system consisting of a silicone ring, top panel, and bottom panel and we applied two polymer films (PF) and one metal plate (MP). This system was based on the principal of sandwiching a test sample between the top panel and the bottom panel. Following the assembly of the culture system, SK-MEL-2 cells were seeded onto Styela Clava Tunic (SCT)-PF, NaHCO₃-added SCT (SCTN)-PF, and magnesium MP (MMP) and incubated at 37℃ for 24 hr and 48 hr. An MTT assay revealed that cell viability was maintained at a normal level in the SCT-PF culture group at 24 or 48 hr, although it rapidly decreased in the SCTN-PF culture group at 48 hr. Furthermore, the cell viability in the MMP culture group was very similar to that of the control group after incubation for 24 hr and 48 hr. Together, these results suggest the sandwich-type mammalian culture system developed here has the potential for the evaluation of the biocompatibility and toxicity of cells against PF- and MP-form biomaterials.

• Korean Security Journal
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• no.28
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• pp.33-56
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• 2011

This study is to practice a analysis of Q-methodological preference degree about the subjects on school curriculum centering around the views of the policemen in active service who are with Gwang Ju and Jeon Nam region. Concretely, this study mixed the subjects on school curriculum related to the police administration of universities located in Gwang Ju and Jeon Nam region and abstracted the twenty seven items as the final question point. Above this, this study integrated the similar or repeated subjects and drew up the question items through seperation process among the different subjects. After this, this study selected the twenty policemen as a first P-sample in active service presently on fourth month in the year 2011. In this process, this study eliminated the materials of six policemen who replyed unhonestly and selected the materials of ten-four policemen as a final effective sample. Furthermore, this study applicated a principal component analysis. This study practiced the I.II.III types of a preference degree analysis of the subjects related to the police administration. the concrete results are as follows: In a I type, the positive consent was showed in the subjects of criminal law, criminal procedure law, criminal speciality law and so on. In a II type, the positive consent was showed in criminal investigation science, emergency measure, the art of self-defence, criminal law, criminal procedure law and so on. In a III type, the positive consent was showed in criminal science, criminal investigation science, criminal procedure law, introduction to police science, police ethics and so on. On this basis, this study concluded the following common opinions. Firstly the actual and evidencial subjects which the policemen in active service feel as the commons were criminal investigation, criminal science, police ethics, criminal speciality law, criminal law business, police administration science, police law practice, emergency measure, the art of self-defence, general rules of civil law, administrative law and so on.

• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.73-80
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• 2007

This study was carried out to separate the heavy toxic metals in eco-building materials by low-temperature pyrolysis, especially arsenic (As) compounds in CCA wood preservative as a solid in char. The pyrolysis was carried out to heat the CCA-treated Hemlock at $280^{\circ}C$, $300^{\circ}C$, $320^{\circ}C$, and $340^{\circ}C$ for 60 mins. Laboratory scale pyrolyzer composed of [preheater$\rightarrow$pyrolyzer$\rightarrow$1st water scrubber$\rightarrow$2nd bubbling flask with 1% $HNO_3$ solution$\rightarrow$vent], and was operated to absorb the volatile metal compound particulates at the primary water scrubber and the secondary nitric acid bubbling flask with cooling condenser of $4^{\circ}C$ under nitrogen stream of 20 mL/min flow rate. And the contents of copper, chromium and arsenic compounds in its pyrolysis such as carbonized CCA treated wood, 1st washing and 2nd washing liquors as well as its raw materials, were determined using ICP-AES. The results are as follows : 1. The yield of char in low-temperature pyrolysis reached about 50 percentage similar to the result of common pyrolytic process. 2. The higher the pyrolytic temperature was, the more the volatiles of CCA, and in particular, the arsenic compounds were to be further more volatile above $320^{\circ}C$, even though the more repetitive and sequential monitorings were necessary. 3. More than 85 percentage of CCA in CCA-treated wood was left in char in such low-temperature pyrolytic condition at $300^{\circ}C$. 4. Washing system for absorption of volatile CCA in this experiment required much more contacting time between volatile gases and water to prevent the loss of CCA compounds, especially the loss of arsenic compound. 5. Therefore, more complete recovery of CCA components in CCA-treated wood required the lower temperature than $320^{\circ}C$, and the longer contacting time of volatile gases and water needed the special washing and recovery system to separate the toxic and volatile arsenic compounds in vent gases.

• Journal of Preventive Medicine and Public Health
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• v.28 no.4 s.51
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• pp.863-873
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• 1995

This report describes a preperation and characterization of canine blood lead(Pb) standard reference material(SRM). Three adult beagle dogs(A, B, and C)were orally dosed with gelatin capsules containing $Pb(NO_3)_2$, equivalent to $10\sim80mg$ Pb/kg body weight. Blood was drawn 24 hours after the dose from the cephalic vein into lead free 500ml Pyrex beaker in which EDTA.K was contained as an anticoagulant. The amount of lead given to individual dog was varied arbitrarily. Three month later, 3 canine animals were orally dosed with lead secondarily to make mixed SRM(D1) which was mixed different concentrations of lead in bloods with A1, B1, and C1 in vitro. The SRMs for A, B, C, A1, B1, C1, and D1 were distributed 2ml each into more than 300 lead free bottles, and were stored in refregerator at $4^{\circ}C$. The amount of lead in canine whole blood samples were determined using a Varian 30A atomic absorption spectrophotometer(AAS) with a model GTA-96 graphite tube atomizer with D2 background correction and a Hitachi Z-8100 AAS with Zeeman background correction. The sensitivity and detection limits for lead determination of Varian 30A were $0.46{\mu}g/L,\;0.34{\mu}g/L,\;and\;0.56{\mu}g/L,\;0.14{\mu}g/L$ of Hitachi Z-8100, respectively. Day to day variations in determination of blood lead concentration in a certain sample were $31.11{\pm}1.36{\mu}g/100ml$ by Varian 30A, and $33.08{\pm}0.82{\mu}g/100ml$ by Hitachi Z-8100, showing the difference of 3% between the two results. At the blood lead concentrations of $56.31{\pm}1.98{\mu}g/100ml(A),\;40.89{\pm}0.80{\mu}g/100ml(B),\;59.01{\pm}1.38{\mu}g/100ml(C)$, the precisions of replicated measurements by AAS were 3.52%, 1.96%, and 2.34%, respectively. Coefficient variation(CV) of SRMs(A, B, and C) within a standard sample were ranged from 0.92% to 7.50%, and those between 5 standard samples were 1.21%, 2.64%, and 1.11%, respectively, showing inter-vial variation of $1{\mu}g/100ml$. Lead levels in SRMs during one month storage were unchanged. The overall recoveries were $89.6\sim100.4%,\;91.6\sim101.9%,\;90.3\sim100.0%$ for A, B, and C SRMs, means were $56.46{\pm}2.69{\mu}g/100ml,\;39.35{\pm}1.89{\mu}g/100ml,\;57.40{\pm}2.31{\mu}g/100ml$, and measurement ranges were$52.88{\pm}59.26{\mu}g/100ml,\;37.47{\pm}41.68{\mu}g/100ml,\;54.80{\pm}60.69{\mu}g/100ml$, respectively. Those results were laid within confidence limits values. The lead concentrations in the mixed sample(D1) stored over one month period were ranged from $32.76{\mu}g/100ml\;to\;33.54{\mu}g/100ml$, with CV ranging from 1.2% to 2.7%. The results were similiar to each of single samples(A1, B1, and C1) in respect of homogeneity and stability. Results of the mixed blood sample analysed after 1 month storage at $4^{\circ}C$ by four other laboratories(L1, L2, L3, L4) were similar with those of our laboratory($L5;31.18{\pm}0.24{\mu}g/100ml$, acceptable range by $CDC;25.18\sim37.18{\mu}g/100ml$), showing the concentrations of $25.91{\pm}1.19{\mu}g/100ml(L1),\;34.16{\pm}0.22{\mu}g/100ml(L2),\;35.68{\pm}0.85{\mu}g/100ml(L3),\;30.95{\pm}0.46{\mu}g/100ml(L4)$ in a each samples.

• The Korean Journal of Nuclear Medicine Technology
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• v.19 no.1
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• pp.37-43
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• 2015

Purpose $^{99m}Tc-DMSA$ renal scintigraphy serves as location, size and shape of kidney, so it has been used for diagnosis and passage observation after the operation or treatment. There are 3 methods of calculating the relative renal uptake ratio such as geometric mean of the counts from the anterior and posterior views, arithmetical mean from the only posterior view and posterior view which applied the renal depths. In this study, we seek to correlation between the change of total relative uptake ratio according to different inspection methods of obtaining the renal count rate. Materials and Methods The phantom experiments proceeded 5 times depending on each renal depth with the kidney phantom and tissue equivalent materials. In the clinical research, we investigated 36 adult patients who had visited our hospital from february to october, 2014 and received $^{99m}Tc-DMSA$ renal scan. The equipment was used as a gamma camera named INFINIA (General Electric Healthcare, milwaukee, USA) and we drew the region of interests through semiautomatic method by using Xeleris Ver. 2.1220 of GE. In addition, we obtained the lateral view of kidney to measure the renal depth of each patient. Then the results were compared with 3 methods of calculating relative renal uptake ratio. Results The phantom studies show when the difference between the left ant right kidney depth were less than 1 cm, there were no statistically significant difference among values calculated through anterior and posterior views and only posterior view (P>0.05), while the excess of 1cm, the results showed a statistically significant change in the value (P<0.05). In case of clinical research, the correlation between total relative uptake ratio by obtaining both sides of image and posterior view applied the kidney depth (r=0.999) was higher than by obtaining only posterior view and applying the kidney depth to one side image (r=0.988). Conclusion This study has found that, the difference of calculating total relative uptake ratio compared with obtaining anterior and posterior views and only posterior view. In order to reduce the error, we recommend the method of obtaining anterior and posterior views and is considered to be useful, particularly the patients have similar uptake ratio of left and right kidney and difficulties of measurements of kidney depth.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.51-55
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• 2004

The most commonly used inorganic nutrient compositions such as Murashige & Skoog medium have been optimized for heterotrophic growth. Therefore, they may not be optimal for photomixotrophic and photoautotrophic growth of plantlets. In photomixotrophic micropropagation, emdium sugar level is often lowered, while light and $CO_2$ levels in vessel are raised, and chlorophyllous explants are used to facilitate photosynthetic carbon acquisition. In a factorial experiment effect of addition (+) and omission(_) of organic materials (OM, 0.5 g ${\cdot}$ $m^{-3}$ each of thiamine, nicotinic acid and pyridoxine and 100 ${\cdot}$ $m^{-3}$ myo-inositiol) combined with three sucrose levels (0, 15, and 30 kg ${\cdot}$ $m^{-3}$) was tested on the growth of potato plantlets. Each of nodal cuttings with a leaf was cultured on 0.1${\times}$$10^{-4}m^{-3}$) MS agar ( 8 kg ${\cdot}$ $m^{-3}$) medium (pH 5.80 before autoclave) in glass test tubes (100 mm${\times}$25mm) capped with a sheet of transparent film with a 6 mm diameter gas permeable filter (5.1 air exchanges ${\cdot}$$h^{-1}$). Cultures were maintained in a room for 27 days at $23^{\circ}C$, 50% RH, 350-450${\mu}mol\;{\codt}\;mol^{-1}CO_2$, 16 h ${\cdot}$ $d^{-1}$ photoperiod at 13${\mu}mol\;{\codt}\;m\;{\codt}\;s^{-1}$ PPFD provided by white cool fluorescent lamps. Growth of potato plantlet in the +OM and -OM treatments were similar, while medium pH was 0.2 scale lower in the latter. Dry weight, % dry matter, and stem diameter enhanced, while shoot to root dry weight ratio, leaf area, chlorophyll concentration per gram dry weight, and medium pH decreased with increasing initial sucrose level. Interaction between OM and sucrose levels was observed in shoot length and medium pH. Results indicate that OM can be omitted from the medium without detrimental effect while addition of sucrose was beneficial for the photomixotrophic growth of potato plantlets under raised light and $CO_2$.

• Journal of agriculture & life science
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• v.45 no.2
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• pp.21-28
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• 2011

Hibiscus cannabinus L is a plant in the Malvaceae family. Kenaf was seeded at June 1st in 2010 and harvested at November 18th and dried and evaluated worth as a bulking agent for livestock composting. Harvested and dried Kenaf was divided into the bast, core and leaf. All materials were grinded by hammer mill and the moisture absorption, moisture evaporation, pH, volume weight and C/N ratio were measured. Kenaf was higher water absorption and evaporation ability than those of sawdust and chaff. The pH values of Kenaf were pH $2.8{\pm}0.01$ - $4.34{\pm}0.02$, which is lower pH value than those of sawdust (pH $5.28{\pm}0.01$) and chaff (pH $6.3{\pm}0.02$). The C/N ratio of Kenaf showed 649 of core, 204 of bast and 70 of leaf, which were lower than sawdust (789.1) but higher than chaff (132). In volume weight test, the materials were divided by particle size of Kenaf, named as group A(${\geq}4cm$), B(${\leq}4cm$, ${\geq}0.25cm$) and C(${\leq}0.25cm$). The volume of weight of group A and B for core, bast and leaf showed similar, but group C showed higher than those of sawdust and chaff. Especially, the volume weight of group C for leaf was 5 times higher than those of sawdust and chaff. This study suggested the possibility of using Kenaf as a bulk agent for composting of livestock manure. This is considered that strengthen the competitiveness of farmers through reducing the cost, prevention of environmental pollution caused by livestock manure and environmentally friendly processing of livestock manure.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.1-16
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• 2018

The standard shift-share analysis decomposes a region's sectoral growth into three components: national, industry-mix, and regional-shift effects. Nevertheless, the three components of the traditional shift-share are not related to the behavior of the regional economies that are neighbors of the region under analysis. We incorporate a spatial structure within this basic formulation, and consider spatial interaction in the decomposition analysis. Daesan Port's export grew steadily at an annualized average rate of 4.0% during 2011-2017, and its rank, in terms of export performance, was 13 in 2010; this rose to 6 in 2016, then declined slightly to 7 in 2017 before reaching 6 as of June, 2018. However, not all ports have a similar growth path. The Onsan Port's share declined from 27.4% in 2011 to 21.0% to 2017, whereas the share of petroleum product exports of Daesan Port increased rapidly, from approximately 8.5% in 2011 to 16.0% in 2017. The standard shift-share analysis shows that petroleum products and basic petrochemicals have a positive regional in dustry-mix effect, but petrochemistry materials and synthetic resins have a negative sign, indicating that the former's exports grow faster than national export, while the increase of the latter's export is slower than national one. The spatial shift-share model indicates that for both petroleum products and basic petrochemicals, Incheon and Ulsan Ports have a positive value for the neighbor-nation regional shift effect and a positive value for the region-neighbor regional shift effect. This paper also shows that Yeosu Port for petroleum products; Ulsan Port for basic petrochemicals; Ulsan, Onsan and Yeosu Ports for petrochemistry materials; and Ulsan, Busan, and Incheon Ports for synthetic resins have a positive value for the neighbor-nation regional shift effect but a negative value for the region-neighbor regional shift effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.278-283
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• 2019

3 kinds of fine powder, Fe-2%Ni alloy powder(N Ltd.) and Fe+2%Ni mixed powder(B Ltd. and S Ltd.), were fabricated into sintered compacts of bending strength specimens and ring type specimens by metal injection molding, debinding and controlling sintering conditions (reduction and sintering atmospheres, sintering temperature, sintering time and cooling rates). Density and magnetic properties of the sintered compacts were evaluated with the following conclusions. (1) When each compact was hold at 1123K for 3.6ks in H2 and sintered at 1623K for 14.4ks in Ar, the density of N, B and S Ltd.'s sintered compacts were measured as 96, 99 and 99%, and oxygen/carbon contents were measured as 0.0041%O/0.0006%C, 0.0027%O/0.0022%C, and 0.160%O/0.0026%C, respectively. (2) Magnetic characteristics of B Ltd. compact in Ar with the best results showed $B_{25}=14.3KG$, $B_r=7.75KG$, and $H_c=2.1Oe$, but not enough as those made by melting process. (3) Magnetic properties of B Ltd. compact which were sintered at 1673K for 14.4ks in Ar gas, and cooled at $0.83Ks^{-1}$ to 1123K and then cooled at $0.083Ks^{-1}$ down to room temperature were measured as $B_{25}=14.8KG$, $B_r=8.3KG$, and $H_c=1.3Oe$, almost similar to those made by melting process. Objected soft magnetic materials properties were obtained through sintering process by controlling sintering conditions (reduction condition, sintering atmosphere, sintering temperature and sintering time) and cooling rates.