• Journal of the Korean Magnetics Society
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• v.13 no.4
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• pp.165-170
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• 2003

M-type hexagonal BaFe$\sub$12/O$\sub$19/ ferrite powder was prepared by sol-gel process. The M-type hexagonal structure with ${\alpha}$ = 5.882 and c = 23.215 ${\AA}$ and its Curie temperature T$\sub$C/ was determined 780${\pm}$3 K. The isomer shifts of ,4f$_2$, 2a. 4f$_1$, 12k, and 2b were indicated 0.26, 0.24, 0.15, 0.25, and 0.24 mm/s, therefore, the valence states of the Fe ions were ferric (Fe$\^$3+/). By the law of approach to saturation (LAS), the effective anisotropy field H$\sub$A/ and crystalline anisotropy constant K$_1$ were estimated. The value of K$_1$ and H$\sub$A/ were K$_1$ = 2.5${\times}$10$\^6/erg/cm^3$ and H$\sub$A/ = 14 kOe, respectively.

• Journal of Radiation Protection and Research
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• v.26 no.4
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• pp.367-374
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• 2001

The study was designed to evaluate the response of sucralfate against the esophageal damage of rat by irradiation. Sixty Sprague-Dawley rats weighing 200-250 gm were divided into six groups including only sucralfate group, the group of 10 Gy or 20 Gy radiation alone, the groups of 10 Gy or 20 Gy radiation-sucralfate combination, and control. Each group was sacrificed at 3, 7, 14, and 28 days after irradiation. For evaluation of the radiation-induced esophageal lesions, there were examined the change of body weight, barium-esophagogram and histopathologic findings. Mean body weight gain was decreased in the groups with 10 Gy or 20 Gy radiation alone and 10 Gy or 20 Gy radiation-sucralfate combination as comparing with control (p=0.03, p=0.02, p=0.04, p=0.02), but there was no difference between the groups of 10 Gy or 20 Gy radiation alone and the groups of 10 Gy or 20 Gy radiation-sucralfate combination. In the 10 Gy and 20 Gy radiation alone groups, barium esophagograms showed diffuse narrowing and stiffness through the entire esophagus from 7 days after irradiation, but there was similar pattern of esophagograms between the groups of 10 Gy radiation-sucralfate combination and the control. Histopathoiogic lesion scores of 10 Gy and 20 Gy radiation groups were significantly higher than the control (p=0.03, p=0.008). In the 10 Gy radiation group, there were significantly higher lesion scores at 3 and 7 days after irradiation as comparing with those in the group of radiation-sucralfate combination (p=0.04, p=0.03). These results suggest that sucralfate might be played as a role of protection from acute radiation-induced esophagitis within the limit of tolerable radiation doses.

• Nuclear Engineering and Technology
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• v.20 no.2
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• pp.105-111
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• 1988

The chemical effects resulting from the capture of the thermal neutron by manganese in various crystalline permanganates, that is, potassium permanganate ammonium permangante and barium permanganate, have been investigated. The effect of pH of solvent on the distribution of radioactive manganese chemical species, that is, cationic $^{56}$ Mn, $^{56}$ MnO$_2$ and $^{56}$ MnO$_4$$^{[-10]}$ produced in the permanganates by $^{55}$ Mn(n, ｒ) $^{56}$ Mn reaction was studied by using various adsorbents and ion-exchanger, that is, zeolite A-3, kaolinite, alumina, manganese dioxide and Dowex-50 The distribution of radioactive MnO$_4$$^{[-10]}$ in kaolinite and alumina has higher than that in other adsorbents and ion-exchanger at a representative pH value of 4, 7 and 9, respectively. The yield of radioactive MnO$_4$$^{[-10]}$ is higher at pH 4 End pH 9 than at pH 7. The thermal annealing behavior of recoil manganese atoms produced in the permanganates by $^{55}$ Mn(n, ｒ) $^{56}$ Mn reaction was also studied. The retention of MnO$_4$$^{[-10]}$ in the thermal annealing is increased as annealing temperature increases when it was treated at 10$0^{\circ}C$ and 13$0^{\circ}C$. The recoil effect of permanganates was explained by the hot zone model.

• Membrane Journal
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• v.19 no.4
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• pp.277-284
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• 2009

In order to select the most suitable membrane to the concentration of vanadium and silica in groundwater, two different commercial NF membrane modules (NE2540-90 and NF90-2540) and three different commercial RO membrane modules (BW30-2540, RE2540-TE, and XLE-2540) were tested. The membrane characteristics test results showed that NE2540-90 module was the most efficient because of higher permeate flux and similar rejection coefficient. Using NE2540-90 module at the transmembrane pressure of $8\;kgf/cm^2$, it was found that the rejection coefficients of vanadium, silica, aluminium, chromium, iron, boron, strontium, and barium were 98.2%, 99.0%, 92.0%, 83.6%, 96.0%, 45.1%, 98.6%, and 69.5%, respectively. It was possible that vanadium and silica contents of groundwater were concentrated into $148.9\;{\mu}g/L$ and 85.8 mg/L respectively by six-stages NF process at the recovery ratio of 15%. The waters produced by NF, which are enriched in vanadium and silica content, are expected to be commercialized the various functional mineral waters.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.609-613
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• 2006

Ba2-xSrxSiO4:Eu2+ phosphor particles with the high photoluminescence (PL) intensity under long wavelength ultraviolet (UV) were prepared by spray pyrolysis. The photoluminescence, morphological and crystalline characteristics of $Ba_{2-x.}Sr_{x.}SiO_4:Eu^{2+}$ phosphor particles prepared by spray pyrolysis were investigated. $Ba_{2-x.}Sr_{x.}SiO_4:Eu^{2+}$ phosphor particles prepared by spray pyrolysis had various colors from bluish green to yellow by changing the ratio of barium and strontium of the host material. In case of x=0, the main emission peak of $Ba_2SiO_4:Eu^{2+}$ phosphor was 500 nm. In case of x=2, the main emission peak of $Sr_2SiO_4:Eu^{2+}$ phosphor was 554nm. $Ba_{2-x.}Sr_{x.}SiO_4:Eu^{2+}$ phosphor particles obtained by spray pyrolysis had spherical shape and hollow structure. On the other hand, the post-treated $Ba_{2-x.}Sr_{x.}SiO_4:Eu^{2+}$ phosphor particles had large size and irregular shape. The $Ba_{1.488}Sr_{0.5}SiO_4:Eu_{0.012}{^{2+}}$ phosphor particles had the maximum PL intensity after post-treatment at temperature of $1300^{\circ}C$ for 3h under reduction atmosphere.

• Applied Biological Chemistry
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• v.22 no.3
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• pp.145-149
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• 1979

The radiochemical purity of $^{14}C(U)-glucose$ solution to be injected to normal laying hen was investigated for studying biokinetics of carbohydrate and lipid metabolism. The liquid scintillation counter was employed for determining the activity of carbon-14. The barium hydroxide and zinc sulfate were adopted to precipitate the protein in the solution. The glucose content in the solution was observed as 0.912 mg per ml, applying Hultman's method. The specific activity of $^{14}C(U)-glucose$ solution was known as 31.3 nCi/mg glucose. The glucose pentaacetate was synthesized to isolate the pure glucose from the solution. The specific activity of pure glucose was measured as 28.5 nCi/mg glucose. Therefore, it was known that the radiochemical purity of the solution was 82.7%.

• Resources Recycling
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• v.7 no.4
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• pp.22-26
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• 1998

The purpose of this experimenL is to investigate the magnetic anisotropy and microwave absorbing properties in M-type Bat territe (${BaFe}_{12-2X}{A}_{X}{Me}_{X}{O}_{19}$), where $Fe_{3+}$ is substituted by $Ti_{4+}$ in A site and $Co_{2+}$ in Me site. The saturation magnetization (Ms) is linearly decreased with the substitution rate(x) and the coerciviLy (He) is rapidly decreased in accordance with the reduction in t the magnetocrystalline anisotropy For the specimen with x=0.8 and thickness of 2 mm, the reflection loss calculated from the n material constants is less than -10 dB (90% absorption) in the frequency range of 10~16 GHz. The absorption loss is pre이.ctcd t to be more than 20 dElern in the frequency range of 12-16 GHz. The results demonstrate that the Ti-Co substituted M-type Ba-ferrite can be effectively used as a microwave absorber at high frequency range.

• 보존과학연구
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• s.32
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• pp.75-87
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• 2011

The materials analysis is important in conservation science for cultural assets since conservators can make appropriate decision of treatment and environment through understanding manufacturing, period and materials. Palsapumdo is the painting of Palsapum which was given by Yi Sun-shin from the emperor Shinjong in The Ming Dynasty. Palsapumdo painted with various pigments on the fabric has remained to adhere a sheet of lining paper. In this study, we carried out the fiber identification about the fabric and lining paper and the analysis of the pigments. This study identified a fabric and a lining paper and analised pigments for the painting. As a result of fabric analysis, it was confirmed as cotton because ribbon twists and shape of kidney bean in a cross section. After the analysis of lining paper, color changed to yellow by Graff "C" staining tests, and had short fiber and tracheid. Therefore, it is supposed to be a paper which is made of conifer pulp. In addition, the results of SEM-EDS, the pigments are indicated as Orpiment($As_2S_3$), Minium($Pb_3O_4$), Hematite($Fe_2O_3$), Emeraldgreen ($C_2H_3As_3Cu_2O_8$), Ultramarine [$2(Na_2O{\cdot}Al_2O_3{\cdot}2SiO_2){\cdot}Na_2S_2$], talc[$Mg_3Si_4O_{10}(OH)_2$], bariumsulfate($BaSO_4$) and brass.

• 재활복지
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• v.22 no.1
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• pp.141-156
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• 2018

The purpose of this study was to examine changes in the swallowing function with chronic stroke patient. Ten chronic stroke patients with dysphagia followed up for 3 months. Eight normal age match subjects were also participated. A total of 18 participated in this study and they were classified into two groups (stroke patient group and normal control group). Participants underwent videofluoroscopic swallowing examination. The swallowing function was evaluated over time. Oral transit duration, pharyngeal transit duration, laryngeal response duration, Modified Barium Swallowing Impairment Profile ($MBSImP^{TM(c)}$), and Functional Oral Intake Scale (FOIS) were applied. Chronic stroke patient group were showed significantly longer oral transit duration, pharyngeal transit duration and laryngeal response duration than normal control group at baseline. After 3 months in stroke patient group, the mean oral components score of MBSImP (1~5) significantly decreased and the mean score on FOIS increased compared to baseline. In conclusion, oral swallowing function and oral intake function improved by the 3 month evaluation. These results describe changes in swallowing function with chronic stroke patients over time and provide basic informations to understand dysphagia.

• Composites Research
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• v.34 no.6
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• pp.357-372
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• 2021

The energy harvesting device is known to be promising as an alternative to solve the resource shortage caused by the depletion of petroleum resources. In order to overcome the limitations (environmental pollution and low mechanical properties) of piezoelectric elements capable of converting mechanical motion into electrical energy, many studies have been conducted on a polymer matrix-based composite piezoelectric energy harvesting device. In this paper, the output performance and related applications of the reported piezoelectric composites are reviewed based on the applied materials and processes. As for the piezoelectric fillers, zinc oxide, which is advantageous in terms of eco-friendliness, biocompatibility, and flexibility, as well as ceramic fillers based on lead zirconate titanate and barium titanate, were reviewed. The polymer matrix was classified into piezoelectric polymers composed of polyvinylidene fluoride and copolymers, and flexible polymers based on epoxy and polydimethylsiloxane, to discuss piezoelectric synergy of composite materials and improvement of piezoelectric output by high external force application, respectively. In addition, the effect of improving the conductivity or the mechanical properties of composite material by the application of a metal or carbon-based secondary filler on the output performance of the piezoelectric harvesting device was explained in terms of the structure of the composite material. Composite material-based piezoelectric harvesting devices, which can be applied to small electronic devices, smart sensors, and medicine with improved performance, can provide potential insights as a power source for wireless electronic devices expected to be encountered in future daily life.