• Journal of IKEEE
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• v.13 no.1
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• pp.57-64
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• 2009

The optoelectrical characteristics of the ZnO nanoparticles (NPs) annealed in vacuum or oxygen condition from $200^{\circ}C$ to $600^{\circ}C$ were examined. Increased on-off ratio (or, the ratio of photocurrent to dark current) was observed when they were annealed at $300^{\circ}C$, $400^{\circ}C$ and $500^{\circ}C$ with the values enhanced about 4 orders compared to the as-prepared ZnO NPs in both annealing conditions, while the maximum efficiency was shown at the annealing temperature of $600^{\circ}C$ for the ZnO NPs annealed in vacuum with the value of 29.8 mA/W and at the temperature of $500^{\circ}C$ for those annealed in oxygen condition with the value of 40.3 mA/W. Photoresponse behavior of the ZnO NPs annealed in oxygen showed the sharp increase right after the ir exposure to the light followed by the slow decay and saturation during steady illumination, differing from the ZnO NPs annealed in vacuum which only exhibited the gradual increase. This difference occurred due to the curing effect of the oxygen vacancies. SEM images indicated no change in their morphologies with annealing, indicating the change in their internal structures by annealing, and most remarkably at $600^{\circ}C$. As for their photoluminescence(PL) spectra, the decrease of the deep-level(DL) emission was observed when they were annealed in oxygen at $400^{\circ}C$, and not at $200^{\circ}C$ and $600^{\circ}C$.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.11-19
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• 2015

The important properties of EVA (ethylene vinyl acetate) redispersible polymer was waterproof, densification of internal pore space of concrete and ball bearing and micro filler. Also, the significant role of polypropylene(PP) fiber was crack control and blockade of movement for deterioration factors. The most studies for EVA were limited in the field of mortar and PP fiber reinforced concrete had been studied in the state of being restricted unit water content, rich mix and mixing much of the fiber without considering construction site. Therefore, the control mix design were applied in ready mixed concrete using 10 % fly ash of total cement weight used in batch plant. On the basis of control mix design, EVA contents ranging from 0 % to 10 % of total cement weight and PP fiber contents ranging from 0 % to 0.5 % of EVA concrete volume were used in the mix designs. The results showed the maximum compressive strength value was measured at EVA 5.0 % and PP fiber 0.1 %, the minimum water absorption ratio was at EVA 10 % and PP fiber 0 %, the durability factor for freezing and thawing resistance was at EVA 5.0 % and PP fiber 0.3 % and the minimum weight reduction ratio of resistance to sulfuric acid attack was at EVA 10 % and PP fiber 0.5 % after curing age 42days. Meanwhile, From these results, PP fiber reinforced EVA concrete would be very benefit, if each optimal mix types were used in hydraulic structures, underground utilities and agricultural structures.

• Journal of the Korean Society for Nondestructive Testing
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• v.19 no.4
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• pp.277-287
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• 1999

Quasi-static tests such as monotonic tension and loading/unloading tension were performed to investigate the bond characteristics and the failure processes for the T-joint specimens made from fiber/epoxy composite material. Two types of specimens, each consists of two components, e. g. skin and frame. were manufactured by co-curing and secondary bonding. During the monotonic tension test, AE instrument was used to predict AE signal at the initial and middle stage of the damage propagation. The damage initiation and progression were monitored optically using m (Charge Coupled Device) camera. And the internal crack front profile was examined using ultrasonic C-scan. The results indicate that the loads representing the abrupt increase of the AE signal are within the error range of 5 percent comparing to the loads shown in the load-time curve. Also it is shown that the initiation of crack occurred in the noodle region for both co-cured and secondarily bonded specimen. The final failure occurred in the noodle region for the co-cured specimen. but at the skin/frame termination point for the secondarily bonded specimen. Based on the results, it was found that two kinds of specimen show different failure modes depending on the manufacturing methods.

• Journal of Society of Preventive Korean Medicine
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• v.18 no.2
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• pp.47-58
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• 2014

Objective : In Oriental medicine, the concept of Preventive Treatment Disease(治未病, PTD) is intended to actively deal with changes in modern disease patterns due to increase in chronic diseases. In China, preventive health service program based on PTD Theory are being carried out aimed at improving and/or preventing people's health. Method : For the introduction of PTD program based preventive service in Korea for the promotion of people's health, I would like to consider its possibility by reviewing the PTD program being conducted in China. Results : China's preventive health service programs based on PTD Theory started in 2008 for the purpose of promoting people's health and reducing medical expenses by providing medical services tailored to individuals. Regarding the effects of PTD program based preventive health service, improvement of discomforting symptoms comprised 73.04% of responses. As to service items, health guidance, Traditional Chinese Medicinal diagnosis, and preparation of health records were answered as being important. The importance of food and internal medicines for preventing and/or curing PTD Theory are also recognized. Also, as to satisfaction level, 90.64% responded as being satisfied in the order of the level of service providers, their attitudes, service processes, items, costs, and environments. Conclusion : As shown above, according to assessments on China's PTD programs, the PTD Theory is being applied to actual public health programs with highly effective results. Hence, it can be seen that such attempt could also be implemented in Korea as part of a scheme for promoting health by means of Korean medicine health promotion programs. However, further researches into concrete implementation schemes will have to be developed in the future as medical systems are different in Korea from in China.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.5
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• pp.307-311
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• 2014

Because of a waveguiding effect and total internal reflection caused by a difference in refractive indices, only 20% of generated light is emitted to the air and the rest is trapped or absorbed in the device. An improvement of outcoupled efficiency of organic light-emitting diodes was studied using a microlens array. Mold of microlens array was fabricated by using photo-lithography with the AZ9260 photoresist, and the microlens array was formed onto the glass substrate using the UV curing agent named ZPU13-440. Device structure consists of microlens/glass/ITO/TPD/$Alq_3$/LiF/Al. It was found that there is an improvement of external quantum efficiency by about 20% at the same current density for the device with the microlens array compared to that of the reference one. Simulated outcoupled efficiency shows the improvement by about 20% for the device with the microlens array compared to that of the reference one. These results are consistent with the experimental ones.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.2
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• pp.278-287
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• 2009

Ji-San, the founder of HyungSang medicine, emphasized food intake and detoxification by stating, "Korean medicine begins with detoxification." Toxin accumulates in one's body unless the internal and external conditions stay in their harmony. The accumulation of toxin is also caused by western medication or one-sided diet, and detoxification should be considered in those cases. HwangRyunHaeDok-Tang reduces fire and heat, and the lesion is likely to locate in the upper body. BangPoongTongSung-San can be used for systemic disease. IkWoon-San also reduces fire and heat but mainly focuses on promoting urination. InSamPaeDok-San has an effect of curing the external symptoms of SangHan(傷寒), in addition to detoxification. SeoGakJiHwang-Tang, SoDok-Eum, and SeoGakSoDok-Eum can resolve the heat-toxin when it is located on the surface. SibJeonDaeBo-Tang enhances the detoxifying function of human body. GhamDu-Tang and JaGeum-Jung have a general effect on detoxification.

• Composites Research
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• v.30 no.6
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• pp.371-378
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• 2017

In this study, hygroelastic behavior of thermosetting epoxy is predicted by molecular dynamics simulations. Since consistent exposures to humid environments lead to macroscopic degradation of polymer composite, computational simulation study of the hygroscopically aged epoxy cell is essential for long-time durability. Therefore, we modeled amorphous epoxy molecular unit cell structures at a crosslinking ratio of 30, 90% and with the moisture weight fraction of 0, 4 wt% respectively. Diglycidyl ether of bisphenol F (EPON862) and triethylenetetramine (TETA) are chosen as resin and curing agent respectively. Incorporating equilibrium and non-equilibrium ensemble simulation with a classical interatomic potential, various hygroelastic properties including diffusion coefficient of water, coefficient of moisture expansion (CME), stress-strain curve and elastic modulus are predicted. To establish the structural property relationship of pure epoxy, free volume and internal non-bond potential energy of epoxy are examined.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.2 s.25
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• pp.35-44
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• 2007

Plowable fill is generally a mixture of sand, fly ash, a small amount of cement and water. Sand is the major component of most flowable fill mixes. Marine dredged soil was adopted for flowable fill instead of fly ash. Natural sea sand and in-situ soil were used for comparison. The flow behavior, hardening characteristics, and ultimate strength behavior of flowable fill were investigated. The unconfined compression test necessary to sustain walkability as the fresh flowble fill hardens was determined and the strength at 3-days appeared to correlate well with the water-to-cement ratio. The strength parameters, like cohesion and internal friction angle, was determined along the curing time. The creep test for settlement potential was conducted. Also, potable falling weight deflectometer(PFWD) test has been carried out for elastic modulus of each controlled low strength materials(CLSM). The data presented show that marine dredged soil and in-situ soil can be successfully used in CLSM.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.3
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• pp.557-562
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• 2002

The present study was made with the aim of finding out the Kamihaepyoijin-tang's effect on the allergic asthma using the Egg-White Implant(EWI) method model recommended by de Siqueira et al. Kamihaepyoijin-tang has widely been prescribed and used in Oriental Medicine for controlling and curing of cough, asthma, nasal obstruction. Previous studies have demonstrated that Kamihaepyoijin-tang had analgesic, anticonvulsive effects. But it is uncertain whether Kamihaepyoijin-tang could inhibit the allergic reaction of rats with experimentally induced allergic asthma using EWI method. With such aim. the respiratory patterns and eosinophil infiltration in the tracheal mucosa of the rats were mainly observed. The results were summerized as follows ; 1. The frequency of malformed respiratory patterns in Kamihaepyoijin-tang treated groups were decreased as compared with the control group. 2. The Ratio of malformed respiratory patterns in Kamihaepyoijin-tang treated groups were significantly decreased as compared with the control group(p<0.02). 3. The eosinophil infiltration in Kamihaepyoijin-tang treated groups were decreased as compared with the control group. 4. The eosinophil infiltration that inside of trachea tissue in Kamihaepyoijin-tang treated groups were significantly decreased as compared with the control group(p<0.05). Depending upon above results, it is considered that Kamihaepyoijin-tang has the inhibitory effects on the allergic asthma of rats and suggested that it could be used in relieving patients of the symptoms which are caused by allergic asthma.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.2
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• pp.277-281
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• 2008

The objectives of this study lie in theoretical establishment of Bobee-tang for curing the asthenic syndrome of spleen through analyzing the component medicines and combination principles of Hyeongok's Bobee-tang, and furthermore, maximizing the clinical use of Bobee-tang. This study analyzed the component medicines and combination principles of Hyeongok's Bobee-tang based on the theory for properties and tastes of herbal medicines from the ${\ulcorner}$Yellow Emperor's Canon of Internal Medicine${\lrcorner}$, the theory for principal herbal medicine, assistant herbal medicine, adjuvant herbal medicine, dispatcher herbal medicine, and the five elements doctrine. Hyeongok's Bobee-tang is an odd prescription, composed of 7 kinds of ingredients : No.1 Radix Ginseng (2don;7.5 g), No.2 Rhizoma Atractylodis Macrocephalae (1don;3.75 g), No.3 Carapax Et Plastrumtestudinis (1don), No.4 Concha Ostreae (1don), No.5 Cortex Cinnamomi (1don), No.6 Rhizoma Zingiberis Praeparatae (1don), and No.7 Radix Glycyrrhizae (1don). First, to cure the asthenic syndrome of the spleen, the methods of invigorating the spleen and the heart, and purging the liver should be used according to the five elements doctrine. Secondly, herbal medicines appropriate for those treatment methods should be chosen according to the theory for properties and tastes of herbal medicine and thirdly, the combination of those herbal medicines should be carried out according to the theory for principal herbal medicine, assistant herbal medicine, adjuvant herbal medicine, dispatcher herbal medicine. As a good example, Hyeongok's Bobee-tang is combined according to the above theories. In conclusion, this formula was created by applying to the theory for properties and tastes of herbal medicines.