• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.592-597
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• 2013

The heat generated at the motor and inverter inside the electric compressor of inverter built-in type is mainly cooled by refrigerant and generally, there is not a thermal problem. However, the close relation of heat transfer from the motor and inverter parts to the compression part affects on compressor efficiency. Also, according to the surrounding environment and system operation condition, the increased temperature of the motor and inverter can affect the power density of the motor system, and especially, the inverter may be prevented to operate by the temperature limits. In this study, we performed thermo-flow analysis of electric compressor motor system, and investigated the heat dissipation enhancement of the motor and inverter. The motor part in the operation region of the electric compressor was generally maintained at low temperature and the inverter part at high compressor speed was lower temperature than the temperature limit of $85^{\circ}C$. However, the case of the inverter at low speed harsh condition was in excess of $10^{\circ}C$. Therefore, in order to solve the thermal problem, the heat reduction technology of the motor and inverter is essential as well as the improvement of flow path in the compressor.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.107-114
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• 1975

To develop the technics of generation shortening for the breeding of rape oil composition. effect of the ethrel and hydroperoxide treatment for the increasing of germination ability during maturing period was investigated. It was the most effect ire for a generation shortening that the seeds after, 10 days treated with $H_2O$$_2$-0.5% and 2, 000ppm of ethrel and after 15 days treated with $H_2O$$_2$-0.5% and 500ppm of ethrel on 15 day after flowering were germinated 76% and 90% respectively. It suggested that effect of ethrel and hydroperoxide was multiple and 4-5 generations could pass in a year because one generation needed only 66-71 days.

• Fisheries and Aquatic Sciences
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• v.22 no.12
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• pp.31.1-31.12
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• 2019

Background: The black-chinned tilapia, Sarotherodon melanotheron, is the most abundant fish species in the Nakwa (an open lagoon) and Brenu (a closed lagoon) in the Central Region of Ghana. Aspects of the life history characteristics and the ecology of the fish populations in both lagoons were studied to assess the bio-ecological status of this important resource. Methods: Fish samples were obtained from fishermen that fish on the Nakwa and Brenu lagoons using cast, drag and gill nets. The age of the fish was assessed from otoliths analysis and its growth modelled following the von Bertalanffy growth function. Morphometric characteristics of the fish populations were analysed using power regression and ANOVA for parameters comparisons, and Student's t test to determine whether species grew isometrically. The percentage occurrence method was used to analyse the stomach contents of the fish. Results: A total of 382 fish samples from both lagoons were measured, comprising 209 from Nakwa lagoon and 176 from Brenu lagoon. The size and weight of fish samples ranged between 3.9-11.5 cm total length and 1.0-27.3 g for Nakwa Lagoon and 5.6-12.8 cm total length and 3.2-29.8 g for the Brenu Lagoon. The estimated von Bertalanffy growth parameters were L∞ = 12.04 cm and K = 2.76/year for the Nakwa Lagoon samples and L∞ = 13.44 cm and K = 3.27/year for Brenu Lagoon samples. Daily otolith incremental rate ranged from 0.01-0.03 mm per day to 0.01-0.02 mm per day for Nakwa and Brenu lagoons, respectively. Stomach content analysis of the fish samples revealed that the species are planktivorous and the range of food varied between the lagoons. Green algae were the most prevalent food item in the stomachs of the fish samples from Nakwa with the frequency of 69% whilst diatoms (80.5%) were most prevalent phytoplanktonic food item for the fish in Brenu lagoon. Conclusions: The estimates of asymptotic length for the species in both lagoons are close to known values of the species length at first sexual maturity and points to intensive fishing pressure. As a consequence, a comprehensive sample-based survey is required in both lagoons to derive estimates of management reference points. The results of the stomach content analysis are beneficial to the construction of diet matrix for ecosystem models of the two systems.

• Journal of the Korean Wood Science and Technology
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• v.41 no.1
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• pp.12-18
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• 2013

Existing wood decks brings out negligent accident because fastener can be pulled-out by cyclic load of pedestrians. When deck and joist are connected, it also causes the problems, which are cracking of wood decks and rapid decay by material of fastener. In this study, strength property of deck unit using reinforced plastic connector made by domestic A company was evaluated. Southern yellow pine (Pinus palustris Miller) were used for deck material. Bending strength of deck units were implemented for fastener type and joist spacing (400, 600 mm). In the result, carbon steel screw into reinforced plastic connector was the best in average bending strength(Joist spacing : 400, 600 mm). In the result of bending strength for joist-width (40, 50, 70, 80 mm), the average maximum bending strength was measured when the joist spacing was 40 mm.

• The Korea Journal of Herbology
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• v.22 no.1
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• pp.71-79
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• 2007

Objectives : This study was designed to establish a characteristic discrimination of internal and external morphological standard of original plants and herbal states in Polygoni Multiflori and Cynanchi Wilfordii Radix. Methods : In this studies, the external-internal morphological standards were determined by using stereoscope and butanol series. Results: 1. The external characteristics of original plants: Polygonum Multiflorum has alternate leaves, and its flower with white color blooms at the shoot apex or leaf axil. In the other hand, Cynanchum wilfordii has opposite leaves, and its flower with yellowish green color blooms at the leaf axil. 2. The physical characteristics of herbal slates: Polygoni Multiflori Radix is red-brown in outer surface pink-brown in section. In the other hand, Cynanchi Wilfordii Radix is earthly-brown in outer surface greyish white in section. 3. The physical characteristics according to the place of production: Demonstrable difference according to the place of production is not seen. Polygoni Multiflori Radix is brown or dark brown in outer surface, soft $Yellow{\sim}dark$ brown in section. In the other hand, Cynanchi Wilfordii Radix is white in outer surface, $white{\sim}weak$ red in section, and has power type. 4. The internal characteristics: Polygonum multiflorum has hetero-vascular bundle and lignification of cork layer is progressive. In the other hand, Cynanchum wilfordii has not hetero-vascular bundle, and lignification of cork layer is weak. Conclusion: In the future, many fundamental study such as how to discriminate between Polygoni Multiflori Radix and Cynanchi Wilfordii Radix in origin and efficacy will be necessary. Also the standard of discrimination must be specific and distinct in that several kinds of fo-ti has been traded. It is considered the results of this study will be furnish κ I the basis Lo succeeding studies and it is needed to extensive comparative study for the same genus-degree of relatedness.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.5
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• pp.241-246
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• 2012

$Yb^{3+}$, $Er^{3+}$ co-doped $SrMoO_4$ ($SrMoO_4$ : $Yb^{3+}/Er^{3+}$) specimens have been successfully synthesized via the complex citrate-gel method and their structural and optical properties were investigated in detail. Under 980 nm excitation, $SrMoO_4$ : $Yb^{3+}/Er^{3+}$ UC phosphors have been emitted strong green luminescence at 530 and 550 nm with weak red emission around 670 nm corresponding to the intra 4f transitions of $Er^{3+}$ ($^4F_{9/2}$, $^2H_{11/2}$, $^4S_{3/2}$) ${\rightarrow}$ $Er^{3+}$ ($^4I_{15/2}$). The optimal doping concentrations of $Er^{3+}$ and $Yb^{3+}$ ions were verified to 2/16 mol% and a possible upconversion mechanism depending on pump power dependence is studied in detail.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.3.1-3.1
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• 2010

Water splitting reaction using photocatalysts is of great interest in the utilization of solar energy [1]. In the present work, visible light-responsive $TiO_2$ thin films (Vis-$TiO_2$) were prepared by a radio frequency magnetron sputtering (RF-MS) deposition method and applied for the separate evolution of $H_2$ and $O_2$ from water as well as the photofuel cell. Special attentions will be focused on the effect of HF treatment of Vis-$TiO_2$ thin films on their photocatalytic activities. Vis-$TiO_2$ thin films were prepared by an RF-MS method using a calcined $TiO_2$ plate and Ar as the sputtering gas. The Vis-$TiO_2$ thin films were then deposited on the Ti foil substrate with the substrate temperature at 873 K (Vis-$TiO_2$/Ti). Vis-$TiO_2$/Ti thin films were immersed in a 0.045 vol% HF solution at room temperature. The effect of HF treatments on the activity of Vis-$TiO_2$/Ti thin films for the photocatalytic water splitting reaction have been investigated. Vis-$TiO_2$/Ti thin films treated with HF solution (HF-Vis-$TiO_2$/Ti) exhibited remarkable enhancement in the photocatalytic activity for $H_2$ evolution from a methanol aqueous solution as well as in the photoelectrochemical performance under visible light irradiation as compared with the untreated Vis-$TiO_2$/Ti thin films. Moreover, Pt-loaded HF-Vis-$TiO_2$/Ti thin films act as efficient and stable photocatalysts for the separate evolution of $H_2$ and $O_2$ from water under visible light irradiation in the presence of chemical bias. Thus, HF treatment was found to be an effective way to improve the photocatalytic activity of Vis-$TiO_2$/Ti thin films. Furthermore, unique separate type photofuel cell was fabricated using a Vis-$TiO_2$ thin film as an electrode, which can generate electrical power under solar light irradiation by using various kinds of biomass derivatives as fuel. It was found that the introduction of an iodine ($I^-/{I_3}^-$) redox solution at the cathode side enables the development of a highly efficient photofuel cell which can utilize a cost-efficient carbon electrode as an alternative to the Pt cathode.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.261-268
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• 2018

The use of electric cable was limited due to the installation time and large space as the increase of power demand and load quantity in side line. In order to solve these problems, the application of busway system which can supply the large current was increasing. But it was lack of methods of performance tests to evaluate the reliability and results of test for busway system. In this paper, we presented items to evaluate the reliability test for epoxy coated busway system with reference to IEC 61349-6. In addition, we proposed items to evaluate the reliability and long term life cycle test for the epoxy coated busway system. The combined acceleration deterioration test that reflects actual conditions of the survey as much as possible was conducted considering both thermal and electrical stresses. The deterioration condition was selected to satisfy fifty years life expectation and the insulation performance verification test of the busway system confirmed the long term life prediction. Furthermore, as test items for reliability assessment of compliance with the environment for the use of temperature, humidity and load current where busway system was installed, thermal overload test, water immersion test, cold shock temperature test and thermal cycle test were performed. And we examined changes in characteristics and abnormality after tests. From results, the test items presented to evaluate performance and reliability of the epoxy insulated busway system were confirmed to be appropriate in this paper, and the performance of the product was also confirmed to be excellent for reliability tests.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1415-1421
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• 2015

This study was performed to investigate the effects of puffed-red ginseng (PRG) powder and drink on blood glucose level and serum lipid profile in streptozotocin (STZ)-induced diabetic rats. For the experimental design, STZ-induced diabetic rats were fed PRG powder-supplemented diets (0.3%, 0.6%) and diluted drinks (0.14%, 0.28%) for 6 weeks. Concentrations of blood glucose during the experimental period decreased to 18.3 mg/dL in the 0.6% PRG diet group and 15.1 mg/dL in the 0.14% PRG drink group. Average reduction rate of blood glucose in the last week compared to reference blood glucose concentration decreased by 19.2% (A group), 37.4% (B group), 18.7% (C group), and 17.3% (D group) in the PRG treatment groups, respectively. These results indicate that PRG affects blood glucose via ginseng saponins administered in diet or drinking water, thereby suggesting that PRG has the ability to prevent increasing blood glucose in mild-induced diabetic rats.

• Korean Journal of Remote Sensing
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• v.32 no.6
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• pp.603-616
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• 2016

In this study, the effects of differential heating by land-use types on flow and air temperature at an Seoul Automated Synoptic Observing Systems (ASOS) located at Songwol-dong, Jongno-gu, Seoul was analyzed. For this, a computation fluid dynamics (CFD) model was coupled to the local data assimilation and prediction system (LDAPS) for reflecting the local meteorological characteristics at the boundaries of the CFD model domain. Time variation of temperatures on solid surfaces was calculated using observation data at El-Oued, Algeria of which latitude is similar to that of the target area. Considering land-use type and shadow, surface temperatures were prescribed in the LDAPS-CFD coupled model. The LDAPS overestimated wind speeds and underestimated air temperature compared to the observations. However, a coupled LDAPS-CFD model relatively well reproduced the observed wind speeds and air temperature, considering complicated flows and surface temperatures in the urban area. In the morning when the easterly was dominant around the target area, both the LDAPS and coupled LDAPS-CFD model underestimated the observed temperatures at the Seoul ASOS. This is because the Kyunghee Palace located at the upwind region was composed of green area and its surface temperature was relatively low. However, in the afternoon when the southeasterly was dominant, the LDAPS still underestimated, on the while, the coupled LDAPS-CFD model well reproduced the observed temperatures at the Seoul ASOS by considering the building-surface heating.