• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.2
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• pp.114-120
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• 2019

This study was carried out to explore the accuracy of near infrared spectroscopy(NIRS) for the prediction of moisture content and chemical parameters on winter annual forage crops. A population of 2454 winter annual forages representing a wide range in chemical parameters was used in this study. Samples of forage were scanned at 1nm intervals over the wavelength range 680-2500nm and the optical data was recorded as log 1/Reflectance(log 1/R), which scanned in intact fresh condition. The spectral data were regressed against a range of chemical parameters using partial least squares(PLS) multivariate analysis in conjunction with spectral math treatments to reduced the effect of extraneous noise. The optimum calibrations were selected based on the highest coefficients of determination in cross validation($R^2$) and the lowest standard error of cross-validation(SECV). The results of this study showed that NIRS calibration model to predict the moisture contents and chemical parameters had very high degree of accuracy except for barely. The $R^2$ and SECV for integrated winter annual forages calibration were 0.99(SECV 1.59%) for moisture, 0.89(SECV 1.15%) for acid detergent fiber, 0.86(SECV 1.43%) for neutral detergent fiber, 0.93(SECV 0.61%) for crude protein, 0.90(SECV 0.45%) for crude ash, and 0.82(SECV 3.76%) for relative feed value on a dry matter(%), respectively. Results of this experiment showed the possibility of NIRS method to predict the moisture and chemical composition of winter annual forage for routine analysis method to evaluate the feed value.

• Journal of Korean Elementary Science Education
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• v.41 no.2
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• pp.283-294
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• 2022

Although the concept of light is important in the elementary school curriculum, substantial research suggests that students and teachers have difficulties in understanding it. Therefore, it is necessary to analyze the reasons for these difficulties-whether it is due to the content or due to the presentation method of contents, structure, and expression. The national curriculum and textbooks of Korea, the US, China, and Japan were comparatively analyzed from the following perspectives: 1) key concepts of light, 2) structure of light units in the textbook, 3) materials, light sources, and optics used in light units. Consequently, there were differences between countries in their inclusion of the concept of light in the curriculum. In particular, the Korean curriculum studies the concept of refraction by a convex lens, whereas the concept of light, light source, and vision is not introduced. Furthermore, countries also differed in their structuring of units. The Korean curriculum was presented segmentally by concept rather than structured according to core ideas or perspectives, and the connection between concepts was unclear. In addition, there were differences between the countries in materials, light sources, and optical instruments to explain key concepts. On using light, the US curriculum provides a purpose and uses light to achieve it, and China and Korea understand the concept. It was divided into the method of using the material to deepen. Based on the results of this analysis, the implications for the elementary science curriculum in Korea were derived as follows. First, it is necessary to introduce concepts sequentially and organize them so that the connection between concepts is well expressed. Second, it is necessary to introduce light and light sources as the predominant concepts. Third, it is necessary to include the principle of seeing objects. Fourth, it is necessary to adjust the material and content level of the refraction concept included in the light and lens unit. Fifth, an integrated approach is required because light has a deep connection with various concepts included in the elementary science curriculum.

• Journal of Biosystems Engineering
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• v.10 no.1
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• pp.54-68
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• 1985

It is desirable to collect the solar thermal energy at relatively high temperature in order to minimize the size of thermal storage system and to enlarge the scope of solar thermal energy utilization. So far the concentrating solar collector has been developed to collect solar thermal energy at relatively high temperature, but it has some difficulties in maintaining the volumetric body of solar collector for long term utilization. On the other hand, the flat-plate solar collector has been developed to collect the solar thermal energy at low temperature, and it has advantages in maintaining the system for long term utilization, since it's thickness is thin and not volumetric. In this study, to develop a solar collector that has both advantages of collecting solar thermal energy at high temperature and fixing conveniently the collector system for long term period, a cylindrical parabolic concentrating solar collector was designed, which has two rows of parabolic reflectors and thin thickness such as the flat-plate solar collector, maintaining the optical form of concentrating solar collector. The characteristics of the concentrating parabolic solar collector newly designed was analysed and the results are summarized as follows; 1. The temperature of the air enclosed in solar collector was all the same as $50^{\circ}C$ in both cases of the open and closed loop, and when the heat transfer fluid was not circulated in tubular absorber, the maximum surface temperature of the absorber was $118-120^{\circ}C$, this results suggested that the heat transfer fluid could be heated up to $118^{\circ}C$. 2. In case of longitudinal installation of the solar collector, the temperature difference of heat transfer fluid between inlet and outlet was $4^{\circ}-6^{\circ}C$ at the flow rate of $110-130{\ell}/hr$, and the collected solar energy per unit area of collector was $300-465W/m^2$. 3. The collected solar energy per unit area for 7 hours was 1960 Kcal/$m^2$ for the open loop and 220 Kcal/$m^2$ for the closed loop. Therefore it is necessary to combine the open and closed loop of solar collectors to improve the thermal efficiency of solar collector. 4. The thermal efficiency of the solar collector (C.P.C.S.C.) was proportional to the density of solar radiation, indicating the maximum thermal efficiency ${\eta}_{max}=58%$ with longitudinal installation and ${\eta}_{max}=45%$ with lateral installation. 5. The thermal efficiency of the solar collector (C.P.C.S.C.) was increased in accordance with the increase of flow rate of heat transfer fluid, presenting the flow rate of $110{\ell}/hr$ was the value of turning point of the increasing rate of the collector efficiency, therefore the flow rate of $110{\ell}/hr$ was considered as optimum value for the test of the solar collector (C.P.C.S.C.) performance when the heat transfer fluid is a liquid. 6. In both cases of longitudinal and lateral installation of the solar collector (C.P.C.S.C.), the thermal efficiency was decreased linearly with an increase in the value of the term ($T_m-T_a$)/Ic and the increasing rate of the thermal efficiency was not effected by the installation method of solar collector.

• Journal of the Korean Chemical Society
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• v.31 no.2
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• pp.168-177
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• 1987

The equilibria of chemical reaction between $\alpha$-Ni(rac-[14]-decane)$^{2+}$ and polar solvents(L; ANT, MFA, DMSO, DMF, and DMA) have been investigated by the spectrophotometric method at $25^{\circ}C$. (The equilibrium constants($K_1$) of) the first step in ANT, MFA, DMSO, DMF, and DMA were 31.0, 27.5, 21.3 15.9, and 6.4, respectively. The smallness of equilibrium constants ($K_2$) of the second step compared with $K_1$, was observed. $\alpha$-Ni(rac-[14]-dacane)$^{2+}$ + L $\leftrightharpoons$ [$\alpha$-Ni(rac-[14]-decane){\cdot}L]$^{2+}$ : $K_1$.[$\alpha$-Ni(rac-[14]-decane){\cdot}L)$^{2+}$+ L $\leftrightharpoons$ [$\alpha$-Ni(rac-[14]-decane){\cdot}$L_2$)$^{2+}$ :$K_2$. The relationship between d-d absorption energy and half-wave potential of complex ions at ACT was considered. Macrocyclic ligands increasing d-d transition energy caused half-wave potentials of Ni(II)-macrocycle to be shifted more positively. The half-wave potentials for Ni(rac-1[14]7-diene)$^{2+}$, Ni(meso-1[14]7-diene)$^{2+}$, Ni(1[14]4-diene)$^{2+}$, $\alpha$-Ni(rac-[14]-decane)$^{2+}$, ${\beta}-Ni(rac-[14]-decane)$^{2+}$, and Ni(meso-[14]-decane)$^{2+}$ reductions were -1.419, -1.431, -1.450, -1.473, and -1.480 (V vs. SCE), respectively. The d-d transition energies ($\nu_{max},\;cm^{-1}$) of the Ni(meso-[14]-decane)$^{2+}$ isomer were discussed with the dielectric constant (${\varepsilon}/{\varepsilon}_0$) of the various solvents, $\nu_{max}(cm^{-1})$ increased with increasing ${\varepsilon}/{\varepsilon}_0$.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.292-292
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• 2016

Transition metal dichalcogenides (TMDs) with a two-dimensional layered structure have been considered highly promising materials for next-generation flexible, wearable, stretchable and transparent devices due to their unique physical, electrical and optical properties. Recent studies on TMD devices have focused on developing a suitable doping technique because precise control of the threshold voltage ($V_{TH}$) and the number of tightly-bound trions are required to achieve high performance electronic and optoelectronic devices, respectively. In particular, it is critical to develop an ultra-low level doping technique for the proper design and optimization of TMD-based devices because high level doping (about $10^{12}cm^{-2}$) causes TMD to act as a near-metallic layer. However, it is difficult to apply an ion implantation technique to TMD materials due to crystal damage that occurs during the implantation process. Although safe doping techniques have recently been developed, most of the previous TMD doping techniques presented very high doping levels of ${\sim}10^{12}cm^{-2}$. Recently, low-level n- and p-doping of TMD materials was achieved using cesium carbonate ($Cs_2CO_3$), octadecyltrichlorosilane (OTS), and M-DNA, but further studies are needed to reduce the doping level down to an intrinsic level. Here, we propose a novel DNA-based doping method on $MoS_2$ and $WSe_2$ films, which enables ultra-low n- and p-doping control and allows for proper adjustments in device performance. This is achieved by selecting and/or combining different types of divalent metal and trivalent lanthanide (Ln) ions on DNA nanostructures. The available n-doping range (${\Delta}n$) on the $MoS_2$ by Ln-DNA (DNA functionalized by trivalent Ln ions) is between $6{\times}10^9cm^{-2}$ and $2.6{\times}10^{10}cm^{-2}$, which is even lower than that provided by pristine DNA (${\sim}6.4{\times}10^{10}cm^{-2}$). The p-doping change (${\Delta}p$) on $WSe_2$ by Ln-DNA is adjusted between $-1.0{\times}10^{10}cm^{-2}$ and $-2.4{\times}10^{10}cm^{-2}$. In the case of Co-DNA (DNA functionalized by both divalent metal and trivalent Ln ions) doping where $Eu^{3+}$ or $Gd^{3+}$ ions were incorporated, a light p-doping phenomenon is observed on $MoS_2$ and $WSe_2$ (respectively, negative ${\Delta}n$ below $-9{\times}10^9cm^{-2}$ and positive ${\Delta}p$ above $1.4{\times}10^{10}cm^{-2}$) because the added $Cu^{2+}$ ions probably reduce the strength of negative charges in Ln-DNA. However, a light n-doping phenomenon (positive ${\Delta}n$ above $10^{10}cm^{-2}$ and negative ${\Delta}p$ below $-1.1{\times}10^{10}cm^{-2}$) occurs in the TMD devices doped by Co-DNA with $Tb^{3+}$ or $Er^{3+}$ ions. A significant (factor of ~5) increase in field-effect mobility is also observed on the $MoS_2$ and $WSe_2$ devices, which are, respectively, doped by $Tb^{3+}$-based Co-DNA (n-doping) and $Gd^{3+}$-based Co-DNA (p-doping), due to the reduction of effective electron and hole barrier heights after the doping. In terms of optoelectronic device performance (photoresponsivity and detectivity), the $Tb^{3+}$ or $Er^{3+}$-Co-DNA (n-doping) and the $Eu^{3+}$ or $Gd^{3+}$-Co-DNA (p-doping) improve the $MoS_2$ and $WSe_2$ photodetectors, respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.19-30
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• 2000

LaF, KzFS1, LBO glass were manufactured successfully by using platinum crucible in LaF and using clay crucible in the KzFS1 and LBO. There was optically transparent and the refractive indexes were measured by minum deviation method of prism. LaF, KzFS1, LBO show that the refrective indexes are $n_d$ = 1.770 in LaF, $n_d$ = 1.603 in KzFS1, $n_d$ = 1.560 in LBO. The transmittance were obtained that LaF has 85%, and KzFS1 has 83% and LBO has 89% in visible range. These glasses have no any absorption spectrum under visible range. Therefore it has no any color.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.6
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• pp.229-236
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• 2014

A stoichiometric mixture of evaporating materials for $MnAl_2S_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $MnAl_2S_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were $630^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The temperature dependence of the energy band gap of the $MnAl_2S_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=3.7920eV-5.2729{\times}10^{-4}eV/K)T^2/(T+786 K)$. In order to explore the applicability as a photoconductive cell, we measured the sensitivity (${\gamma}$), the ratio of photocurrent to dark current (pc/dc), maximum allowable power dissipation (MAPD) and response time. The results indicated that the photoconductive characteristic were the best for the samples annealed in S vapour compare with in Mn, Al, air and vacuum vapour. Then we obtained the sensitivity of 0.93, the value of pc/dc of $1.10{\times}10^7$, the MAPD of 316 mW, and the rise and decay time of 14.8 ms and 12.1 ms, respectively.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.563-575
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• 2020

The purpose of this study is to evaluate the activation characteristics that occur in a linear accelerator for container security inspection. In the computer simulation design, first, the targets consisted of a tungsten (Z=74) single material target and a tungsten (Z=74) and copper (Z=29) composite target. Second, the fan beam collimator was composed of a single material of lead (Z=82) and a composite material of tungsten (Z-74) and lead (Z=82) depending on the material. Final, the concrete in the room where the linear accelerator was located contained magnetite type and impurities. In the research method, first, the optical neutron flux was calculated using the MCNP6 code as a F4 Tally for the linear accelerator and structure. Second, the photoneutron flux calculated from the MCNP6 code was applied to FISPACT-II to evaluate the activation product. Final, the decommissioning evaluation was conducted through the specific activity of the activation product. As a result, first, it was the most common in photoneutron targets, followed by a collimator and a concrete 10 cm deep. Second, activation products were produced as by-products of W-181 in tungsten targets and collimator, and Co-60, Ni-63, Cs-134, Eu-152, Eu-154 nuclides in impurity-containing concrete. Final, it was found that the tungsten target satisfies the permissible concentration for self-disposal after 90 days upon decommissioning. These results could be confirmed that the photoneutron yield and degree of activation at 9 MeV energy were insignificant. However, it is thought that W-181 generated from the tungsten target and collimator of the linear accelerator may affect the exposure when disassembled for repair. Therefore, this study presents basic data on the management of activated parts of a linear accelerator for container security inspection. In addition, When decommissioning the linear accelerator for container security inspection, it is expected that it can be used to prove the standard that permissible concentration of self-disposal.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.347-352
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• 1983

To characterize humus fractions in soil, visible, ultraviolet and infrared absorption spectra of humic acids in alkaline solutions and hymatomelanic acids in ethanol solutions extracted by Stevenson's method from paddy rice soils, peats, and volcanic ash soils were analyzed. The spectra patterns of both fractions in visible and ultraviolet ranges did not have any peak and the absorbance decreased as the wavelength increased. Visible and ultraviolet spectra of the solutions from all the peats, volcanic ash soils and paddy rice soil were very similar each other but absorbances were slowly declined in the order of volcanic ash soils, peats and mineral paddy soils. The infrared spectra of the two solutions appeared in a typical pattern, showing a few broad peaks. The main absorption bands were in the regions of $3400cm^{-1}$ (hydrogen bonded OH), near $2900cm^{-1}$ (aliphatic CH), $1720cm^{-1}$ (C=O of COOH, C=O of carbonyl), $1625cm^{-1}$ (aromatic C-C conjugated with C=O and/or COO-), $1400-1450cm^{-1}$ (CH stretch), $1200-1250cm^{-1}$ (CaO stretch of phenolic OH or OH-deformation of COOH) and $1050cm^{-1}$. The hymatomelanic acid fractions, however, had spectra that were characterized especially by very distinct absorption at $2900cm^{-1}$ and $1720cm^{-1}$, for aliphatic CH and carbonyl stretching vibration respectively in addition to the weaker bands for COO- or aromatic CH vibration at $1625cm^{-1}$, as compared to humic acid. No differences were noted in the general patterns of the spectograms of both fractions extracted. Analyses of the functional groups revealed little differences between peats and paddy soils, although total acidity and the content of carboxyl groups were decreased in the order of volcanic ash soils, peats and mineral paddy soils.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1071-1080
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• 2017

This study examined the adhesiveness of beneficial intestinal bacteria to whole-grains using confocal scanning laser microscopy (CLSM), to demonstrate the prebiotic effects of whole-grains, and to develop prebiotic puffed snacks with these whole-grains. CLSM has been used to observe the adhesiveness of Lactobacillus acidophilus, which belongs to beneficial intestinal bacteria, to whole-grain powders using optical sectioning techniques. The enhanced effects on the growth of beneficial intestinal bacteria with the hot water grain extract were verified using an indirect count method. Finally, a puffed snack was produced with the prebiotic effect and the quality was evaluated by checking the chromaticity and degree of hardness. As a result, L. acidophilus exhibited adhesive ability to whole-grain powders and growth of selected beneficial intestinal bacteria were improved significantly. The Hunter L value of the developed puffed snack increased when seasoning was added. The hardness of the puffed snack with seasoning was higher than that of the control. The results of a sensory evaluation showed that the puffed snack with seasoning was highly rated in the overall preference compared to the control.