• 한국재료학회지
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• 제25권12호
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• pp.703-707
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• 2015

In this study, we investigated the effect of annealing conditions on the ferromagnetic resonance(FMR) of yttrium iron garnet ($Y_3Fe_5O_{12}$, YIG) thin film prepared on gadolinium gallium garnet ($Gd_3Ga_5O_{12}$, GGG) substrate. The YIG thin films were grown by rf magnetron sputtering at room temperature and were annealed at various temperatures from 700 to $1000^{\circ}C$. FMR characteristics of the YIG thin films were investigated with a coplanar waveguide FMR measurement system in a frequency range from 5 to 20 GHz. X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) were used to characterize the phase formation, crystal structure and composition of the YIG thin films. Field dependent magnetization curves at room temperature were obtained by using a vibrating sample magnetometer(VSM). The FMR measurements revealed that the resonance magnetic field was highly dependent on the annealing condition: the lowest FMR linewidth can be observed for the $800^{\circ}C$ annealed sample, which agrees with the VSM results. We also found that the Fe and O composition changes during the annealing process play important roles in the observed magnetic properties.

• 보존과학연구
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• 통권30호
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• pp.203-215
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• 2009

In the conservation treatment of wood remains, polymers, treatment methods, and treatment period can be varied, depending on the percentage of moisture content and species of trees. Thus, in order to apply the appropriate conservation treatment, a lot of information from the wood remains are required. Despite the information from the wood remains, testing a part of the wood remains is necessary to get information about the polymers. When the wooden coffin made of camphor trees was excavated, it was cracked in the section of radiation, and there were hairlines cracks. Therefore, without any conservation treatment, it is impossible to restore it. This experiment is for the conservation treatment of the wooden coffin excavated from Songhyun-dong tombs No 7, Changnyeong. For this experiment, I used camphor trees from Jejudo. The purpose of this experiment is to asses the possibility of preliminary testing materials before the conservation treatment on the wooden coffin. After the camphor trees from Jejudo are artificially aged by Fenton's reagent, they are As a result of oxidation by Fenton, the degree of oxidation is high in proportion to the amount of peroxide and iron sulfate. Among several samples, the sample 'na' made the most similar result to the wooden coffin from Songhyun-dong. If I use this condition to make the sample in polymer tests, it is very helpful to find the most suitable polymer for the conservation treatment of wooden coffin. After the same species of trees are oxidized by Fenton and they become the similar condition, we are able to find suitable methods of conservation treatment. The suitable methods reduce the demage of the remains and make us to get more information. Thus, we are able to carry out conservation treatment more exactly.

• 한국자기학회지
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• 제9권1호
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• pp.29-34
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• 1999

자성 garnet Y2.5La0.5Fe5O12의 분말을 ethylene glycol을 용매로 이용한 sol-gel방식으로 합성하였다. 시료의 결정학적 및 자기적 성질을 x선 회절기(XRD), 진동시료 자화기(VSM), 그리고 Mossbauer 분광기를 이용하여 연구하였다. 분말의 경우 100$0^{\circ}C$에서 단일상의 garnet결정을 얻었으며 결정구조는 cubic구조이며 격자상수는 12.415$\AA$이었다. Mossbauer spectrum은 13K부터 700K까지 측정하였으며 Fe는 모두 +3가 상태로 16(a)와 24(d)site에 존재함을 확인하였다. spin wave 상수는 B3/2=0.32$\pm$0.05, C5/2=0.18$\pm$0.05였으며, Debye 온도는 24(d)site인 경우 382K 그리고 16(a) site인 경우 246K였다. VSM 실험으로부터 상온에서 포화 자화값(Ms)은 25emu/g이었다.

• 한국자기학회지
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• 제4권1호
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• pp.25-31
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• 1994

코발트와 철의 이온을 혼합한 산성수용액 중에서, 알루미늄 양극산화피막에 전해석출 하여 제작된 자성막은, 코발트조성이 증가함에 따라 발크합금의 경우와 마찬가지로 상전이(phase shifting) 하였다. 입자직경이 $150\;{\AA}$의 시료의 경우 조성이 25-35 at% Co에서 큰 포화자화, 고항자력, 큰 자기이방성 에너지 및 우수한 각형비 등에 기인하는 큰 자기에너지 적($BH_{max}$)이 얻어진다. 그러나 입자직경이 $450\;{\AA}$의 경우에는, 코발트가 50-70 at% 일때 초기석출부 에 강자성체인 FeC가 아주 강하게 배향하므로, 입자의 큰 형상이방성(수직자기이방성)이 없어지고 면내 방향의 자기이방성을 나타낸다. 그리고 같은 조성에서 초기석출부를 제거하여 FeC의 영향을 없앨때, 주직자기이방성이 회복되었다.

• Journal of Preventive Medicine and Public Health
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• 제55권6호
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• pp.559-567
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• 2022

Objectives: This study aimed to assess the effect of complete coverage and content of available antenatal care (ANC) on the incidence of low birth weight (LBW) in 4 countries belonging to the Association of Southeast Asian Nations (ASEAN). Methods: Measures of complete coverage and content of ANC services included the frequency of ANC visits and the seven service components (blood pressure measurement, iron supplementation, tetanus toxoid immunization, explanations of pregnancy complications, urine sample test, blood sample test, and weight measurement). The complete coverage and content of ANC services were assessed as high if more than 4 ANC visits and all seven components were delivered. Multivariable logistic regression with complex survey designs was conducted using Demographic Health Survey data from the 4 ASEAN countries in question from 2014 to 2017. Results: The proportion of LBW infants was higher in the Philippines (13.8%) than in Indonesia (6.7%), Cambodia (6.7%), or Myanmar (7.5%). Poor ANC services were associated with a 1.30 times higher incidence of LBW than a high level of complete coverage and content of ANC services (adjusted odds ratio [aOR], 1.30; 95% confidence interval [CI], 1.11 to 1.52). In addition, the risk of LBW was higher in the Philippines than in other countries (aOR, 2.25; 95% CI, 2.01 to 2.51) after adjusting for mothers' demographic/socioeconomic factors, health behaviors, and other factors. Conclusions: In sum, complete coverage and content of ANC services were significantly associated with the incidence of LBW in Indonesia, Cambodia, and Myanmar. The Philippines did not show statistically significant results for this relationship, but had a higher risk of LBW with poor ANC.

• International Journal of Computer Science & Network Security
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• 제24권6호
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• pp.200-206
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• 2024

Laser induced breakdown spectroscopy (LIBS) technique has been used for the elemental composition of the soils. In this technique, a high energy laser pulse is focused on a sample to produce plasma. From the spectroscopic analysis of such plasma plume, we have determined the different elements present in the soil. This technique is effective and rapid for the qualitative and quantitative analysis of all type of samples. In this work a Q-switched Nd: YAG laser operating with its fundamental mode (1064 nm laser wavelength), 5 nanosecond pulse width, and 10 Hz repetition rate was focused on soil samples using 10 cm quartz lens. The emission spectra of soil consist of Iron (Fe), Calcium (Ca), Titanium (Ti), Silicon (Si), Aluminum (Al), Magnesium (Mg), Manganese (Mn), Potassium (K), Nickel (Ni), Chromium (Cr), Copper (Cu), Mercury (Hg), Barium (Ba), Vanadium (V), Lead (Pb), Nitrogen (N), Scandium (Sc), Hydrogen (H), Strontium (Sr), and Lithium (Li) with different finger-prints of the transition lines. The maximum intensity of the transition lines was observed close to the surface of the sample and it was decreased along the axial direction of the plasma expansion due to the thermalization and the recombination process. We have also determined the plasma parameters such as electron temperature and the electron number density of the plasma using Boltzmann's plot method as well as the Stark broadening of the transition lines respectively. The electron temperature is estimated at 14611 °K, whereas the electron number density i.e. 4.1 × 10¹⁶ cm^-3 lies close to the surface.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2335-2347
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• 2023

As medical facilities are usually built at urban areas, special concrete aggregates and evaluation methods are needed to optimize the design of concrete walls by balancing density, thickness, material composition, cost, and other factors. Carbon treatment rooms require a high radiation shielding requirement, as the neutron yield from carbon therapy is much higher than the neutron yield of protons. In this case study, the maximum carbon energy is 430 MeV/u and the maximum current is 0.27 nA from a hybrid particle therapy system. Hospital or facility construction should consider this requirement to design a special heavy concrete. In this work, magnetite is adopted as the major aggregate. Density is determined mainly by the major aggregate content of magnetite, and a heavy concrete test block was constructed for structural tests. The compressive strength is 35.7 MPa. The density ranges from 3.65 g/cm³ to 4.14 g/cm³, and the iron mass content ranges from 53.78% to 60.38% from the 12 cored sample measurements. It was found that there is a linear relationship between density and iron content, and mixing impurities should be the major reason leading to the nonuniform element and density distribution. The effect of this nonuniformity on radiation shielding properties for a carbon treatment room is investigated by three groups of Monte Carlo simulations. Higher density dominates to reduce shielding thickness. However, a higher content of high-Z elements will weaken the shielding strength, especially at a lower dose rate threshold and vice versa. The weakened side effect of a high iron content on the shielding property is obvious at 2.5 µSv=h. Therefore, we should not blindly pursue high Z content in engineering. If the thickness is constrained to 2 m, then the density can be reduced to 3.3 g/cm³, which will save cost by reducing the magnetite composition with 50.44% iron content. If a higher density of 3.9 g/cm³ with 57.65% iron content is selected for construction, then the thickness of the wall can be reduced to 174.2 cm, which will save space for equipment installation.

• Journal of Magnetics
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• 제11권2호
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• pp.87-89
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• 2006

CoFeV thin film alloys were fabricated by electrodeposition, and the dependences of their magnetic properties on the current density were investigated using an X-ray diffractometer and a vibrating sample magnetometer. The deposited Co increased from about 45 to 60 wt.% with increasing current density until $25mA/cm^2$ whereas the deposited Fe decreased from about 55 to 40 wt.% with increasing current density until $25mA/cm^2$. The deposited V, about 2 wt.%, was independent of the current density. The current efficiencies of electrodeposition decreased linearly from about 40 to 29% with increasing current density. The X-ray diffraction measurement showed that all peaks of the CoFeV films were consistent with those of a typical Co hcp and Fe bcc mixed phase. An increase in the current density decreased the grain size and increased the lattice constant. The saturation magnetization increased from about 2.2 to 2.5 T with increasing current density. The coercivity measured in the perpendicular direction decreased from 260 to 120 Oe with increasing current density; a drastic drop of 60 Oe occurred at $5mA/cm^2$. The coercivity measured in the in-plane direction remained almost unchanged, at about 20 Oe, with increasing current density.

• 지역사회간호학회지
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• 제15권3호
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• pp.483-495
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• 2004

Purpose: The purpose of this study was to explore the perimenstrual discomforts and dietary intake levels among normal women. Method: A prospective and descriptive study examined 38 women aged 23 46years of age. The data collection period lasted from April 1 to June 30, 2003. The participants were asked to keep a diary recording perimenstrual symptoms and food intake for 50 days. Results: There was a significant difference in physical symptoms of perimenstrual discomforts (F=6.95. p=.001). but there was no significant difference in dietary intake level according to three different phases of a menstrual cycle. The significant dietary intake variables correlated to PMS included energy, protein, Vitamin E, Vitamin $B_2$, niacin, Vitamin $B_6$, folic acid, phosphorus, iron, and zinc. They were negatively related to perimenstrual discomforts. Conclusion: Balanced diet intake will be necessary for not only the perimenstrual discomforts but also the general health promotion of the entire population. The dietary and nutritional assessment should be done prior to nursing interventions, and nutritional counseling and education should be given based on individual differences. In a further study, the effects of dietary composition on specific symptoms will be replicated with a large sample, and development of a diet intervention program for perimenstrual discomforts is recommended.

• 한국세라믹학회지
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• 제38권8호
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• pp.710-715
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• 2001

반응소결공정(RSP : Reaction Sintering Process)을 이용하여 YF댸₃와 Fe₂O₃의 성분에 소결첨가재 Bi₂O₃를 첨가하여 YIG를 합성하였다. Bi₂O₃첨가량과 소결온도에 따른 YIG 소결체의 미세구조 및 자기적 특성변화에 대해 주사전자현미경, X-선 회절분석기 및 시료 진동형 자력계를 이용하여 조사하였다. 소량의 소결첨가재 Bi₂O₃첨가시 YIG 소결체의 격자상수는 12.387에서 12.420 Å으로 증가하였다. 이는 상대적으로 이온반경이 큰 Bi 이온이 12면체 Y 이온 자리로 치환되었기 때문인 것으로 여겨진다. Bi₂O₃를 1.0 wt% 첨가하였을 때 비교적 균질한 미세구조를 보였으며, 1350℃에서 소결한 YIG의 밀도가 이론밀도의 98% 이상의 치밀화를 보였다. Bi₂O₃가 0.0 wt%에서 1.5 wt%로 첨가량이 증가함에 따라 상온에서의 포화자화값(M/sub s/)은 조금씩 증가하는 경향을 보였으나 큰 변화는 없었다. 반응소결공정을 이용 YIG 소결시 소결첨가제 Bi₂O₃가 1.0 wt%이고, 소결온도 1350℃에서 비교적 우수한 소결특성과 자기특성을 가지는 YIG 소결체를 얻을 수 있었다.