• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.813-819
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• 2006

Skid Resistance is a index to represent the friction between tire and road surface, which influences driving safety. Skid resistance varies with the conditions of tire, abrasion of road surface, vehicle speed, drying, wet and freezing condition of road surfaces. Especially, freezing occurs when temperature drops below $0^{\circ}C$ followed by snow or rain causes decrease of skid resistance. To recover the decreased skid resistance deicing work is applied. As a results of deicing works, freezing condition is changed into wet condition. However the wet road surfaces containing the remaining deicings agents may not show the skid resistance of normal wet condition. In this study, skid resistances in the condition of freezing, deicing process and deicing agents remained after snow-removal are evaluated. The test results, skid resistance recover quickly when Pre-wetted salt spreading and NaCl was used as deicing method. Skid resistance of Deicing agents remained on the road surface showed that concrete is higher than asphalt. superior effect. Recovery rate of skid resistance by comparison wet condition is 54~80%.

• Journal of Korean Medical classics
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• v.13 no.2 s.17
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• pp.174-188
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• 2000

The meaning of Tiangui(天癸) in $Suwen{\cdot}Shanggutianzhenlun\;素問{\cdot}上古天眞論$ is very important because it has the cause of 'having a child' and it shows the signs to being healthy. But until now there have been many arguments about what the correct meaning of Tiangui is. The most important thing in these arguments is to compare and analyze Neijing(內經) commentators' views, and to understand differences between their views. So I compared and analyzed by focusing on Neijing(內經) text, the other books with explanatory notes, and other commentators' views, and, after that. I got the following results. 1. On the meaning of Tian(天), Wangbing(王氷) and Mashi(馬蒔) considered that it is inborn. Zhangjiecong(張志聽) considered it as the Yang(陽) producing Yin(陰) Zhangjiebin(張介賓) regarded it as the Yang(陽) of Gua symbol. On the meaning of the Gui(癸). Zhangjiebin(張介賓) said that it is Yin qi(陰氣) which is the prior step to Xing(形). Mashi(馬蒔) and Zhangzhicong(張志聽) said that it is spirit or Jingxue(spiritual sanguine) which is the concrete constituents in our body. 2. On the relation bet ween Tian(天) and Gui(癸), Mashi(馬蒔) and Zhangzhicong(張志聽) said that Gui(癸) is made from Tian(天), and Zhangjiebin(張介賓) said that Tian is intrinsic in Gui(癸). 3. On the relation between Tiangui(天癸) and Jingxue(精血), Yangshangshan(楊上善). Wangbing(王氷), and Zhangjiebin(張介賓) regarded Tiangui(天癸) as a concrete matter which is the prior step to becoming Jingxue(精血). Mashi(馬蒔) and Zhangjiecong(張志聽) considered Tiangui(天癸) as a concrete matter. Mashi(馬蒔) considered Tiangui(天癸) as Jing(精)which is directly related to pregnancy. Zhangjiecong(張志聽) regarded Tiangui(天癸) as Jingxue(精血) which controls general physiology of men and women. 4. On the function of Tiangui(天癸), Yangshangshan(楊上善) and Wangbing(王氷) considered that Tiangui (天癸) has relation to menstruation. pregnancy. and, production and extinction of Jing(精). Zhangjiecong(張志聽) argued that Tiangui(天癸) strengthens and warms muscle and derma. and controls differential physiology between men and women, and said that the maintenance of its activity is based on the acquired spirit of food. A book of 『Huangti Neijing Yanjiu Dacheng(黃帝內經硏究大成)』 said that the function of Tiangui(天癸) is to promote generation, to develop the second sexual symbol, and to make growing and aging in body. It also said that Tiangui(天癸) has some relation to kidney and other organs, Chong Meridian, Ren Meridian, Du Meridian, and Dai Meridian. 5. Other commentators of 『Neijing(內經)』 accepted the meaning of Tiangui(天癸) as the prior step of both man's spiritual overflowing and woman's menstruation. 6. On the relation between Tiangui(天癸). and, Cheng and Ren Meridians, Yangshangshan(楊上善) and Zhangjiecong(張志聽) said that Tiangui(天癸) has direct relation with two meridians. Wangbing(王氷) said that Tiangui(天癸) and two meridians have no direct relation. Now I compared commentaors' views of Tiangui(天癸) and studied the differences between their views. I concluded that on the concept of Tiangui(天癸), Zhangjiebin(張介賓)'s explanations express well its connotative meaning. And on the function of Tiangui (天癸), Zhangjiecong(張志聽)'s explanations are excellent because he organized well his seniors' views, and extended its meaning by showing Neijing(內經)'s phrases related to Chong and Ren Meridians. Also, Mashi(馬蒔) suggested that if Tiangui(天癸) comes earlier than normal. people will die soon. But I think that more studies on male and female bodies are needed as to Mashi(馬蒔)'s argument.

• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.531-537
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• 2009

In this study alkali reactivity of crushed stone was conducted according to the ASTM C 227 that is traditional mortar bar test, and C 1260 that is accelerated mortar bar test method. The morphology and chemical composition of products formed in mortar bar, 3 years after the mortar bar tests had been performed, were examined using scanning electron microscopy (SEM) with secondary electron imaging (SEI) and electron probe microanalysis (EPMA) with backscattered electron imaging (BSEI). The crushed stone used in this study was not identified as being reactive by ASTM C 227. However, mortar bars exceeded the limit for deleterious expansion in accelerated mortar bar test used KOH solution. The result of SEM (SEI) analysis, after the ASTM C 227 mortar bar test, confirmed that there were no reactive products and evidence of reaction between aggregate particles and cement paste. However, mortar bars exposed to alkali solution (KOH) indicated that crystallized products having rosette morphology were observed in the interior wall of pores. EPMA results of mortar bar by ASTM C 227 indicated that white dots were observed on the surface of particles and these products were identified as Al-ASR gels. It can be considered that the mortar bar by ASTM C 227 started to appear sign of alkali-silica reaction in normal condition. EPMA results of the mortar bar by ASTM C 1260 showed the gel accumulated in the pores and diffused in to the cement matrix through cracks, and gel in the pores were found to be richer in calcium compared to gel in cracks within aggregate particles. In this experimental study, damages to mortar bars due to alkali-silica reaction (ASR) were observed. Due to the increasing needs of crushed stones, it is considered that specifications and guidelines to prevent ASR in new concrete should be developed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.347-355
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• 2021

During the earthquake, for multi-story structure, if the first floor is soft, the deformation will concentrate on that floor causing a serious damage to the column members which might leads to the collapse of the whole structure like Piloti structure during the Pohang earthquake in Korea. According to the 2016 National Disaster Management Research Institute's "Investigation of Seismic Reinforcement and Cost Analysis of Domestic Non-seismic Buildings", the rate of seismic resistance of private reinforced concrete buildings was 38.3 %. Among them, it was reported that the seismic-resistance ratio of the two to five-story structures was less than 50 %. Accordingly, the government is trying to improve the seismic rate through support projects, but the conventional seismic reinforcement methods are still expensive, and emergency construction is difficult. Therefore, in this study, the field applicability was evaluated by improving the reinforcement method using Velcro, which was developed through the research project of the Ministry of Land, Transport and Maritime Affairs in 2014. In order to improve the performance of the Velcro reinforcement method, introducing the initial tension of Velcro using high foaming rigid urethane filling between the Velcro and concrete of the columns was applied. Additionally, an experiment was conducted to evaluate the ductility of Velcro specimen from the concrete confinement effect. As a result, the ductility of the Velcro specimen was improved compare to Normal specimen. However, the energy dissipation capacity of VELCRO2 is better than VELCRO1, yet the maximum ductility of those two specimens did not show a significant difference. Therefore, the improvement of the internal filler material is still needed to have a better maximum ductility.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.13-20
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• 2005

The effects of pectin on obesity was studied using 3T3-L1 pre-adipocytes and rats fed 20% high fat diets. The concentration of leptin released from 3T3-L1 adipocytes in the presence of pectin was significantly decreased by 85% compared to that of the control (p<0.05), however, glycerol concentration was not changed. These data indicate that pectin seems to inhibit lipids accumulation in the adipocytes rather than enhance the lipolytic activity. Forty Sprague Dawley rats were fed 20% high fat diet for 8 weeks to induce obesity and then divided equally into four groups. Experimental groups were normal diet group (ND), high fat diet group (HFD), HDF with 10% pectin group (HFP10), and HDF with 20% pectin group (HFP20). Diet for the each group was prepared to be iso-caloric following AIN-76 guideline. After obesity was induced, rats were placed on an restricted diet for 9 weeks. The body weight of HFD increased 50% (p<0.05) compared to the ND, while it was decreased by 12% and 16% for HFP10 and HFP20, respectively (p<0.05). The relative amount of visceral fats for HFDl0 and HFD20 were decreased by 45% and 59% compared to that of HDF (130%), respectively (p<0.05). Pectin seems to have a greater effect on reducing visceral fats accumulation than weight reduction. Significantly increased level of triglyceride, total cholesterol or LDL-cholesterol in the plasma of HFD was returned to the normal or even below the normal by pectin diet, while the level of HDL-cholesterol increased. Lipid lowering effect was also observed in the liver and heart. These effects of pectin were dosedependent. In conclusion, the beneficial effect of pectin on the obesity was observed from cell culture experiment and animal study in terms of inhibiting the accumulation of lipids in the adipocytes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.65-73
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• 2013

Recently the exterior attaching reinforcement method is being often used by using FRP (Fiber Reinforced Polymer) as a method of strengthening concrete structure. this FRP exterior attaching reinforcement method has several advantages like high intensity, stiffness, good durability and easy installment comparing to its weight. but its structure is airtight covered by reinforcement material whose water permeability is low and water can't be discharged, thus it may provoke a damage to the structure after a long while. the main purposes of this study are to develop GFRP reinforcement material which can discharge the surface water properly and to measure its special functions. for this, we have changed the normal reinforcement material to water permeable structure and measured its water permeance modulus by an indoor test which shows the process of water permeance with the parameter of contained GFRP quantity. also tried to verify the measured value of the water permeance modulus in theory by analyzing the numbers on water permeance process. the test result showed that the biggest quantity of water, 0.5129 g/h $m^2$ was discharged when the fiber contained quantity reached at 75% and the tensile strength was also biggest by 476.6MPa at 75%, so it appeared that COSREM GP panel with 75% fiber contained quantity is the best in ventilation and structure.

• Fire Science and Engineering
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• v.31 no.3
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• pp.97-105
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• 2017

Because asphalt is a solid at normal temperature and is not a hazardous material as stipulated in the Safety Management Act on Hazardous Materials, it is often recognized as having no risk of fire or explosion. On the other hand, it is as dangerous as flammable liquid because it is heated to $170-180^{\circ}C$ and stored in a storage tank. This study analyzed the risk of fire and explosion during the storage and handling of asphalt and the actual conditions of asphalt regulations by fire service organizations. Moreover, this study analyzed the domestic case of explosions in the production process of asphalt concrete (ASCON) and domestic and foreign cases of asphalt storage tank explosions. The analysis suggested that unlike Japan, Korea has no asphalt regulations in fire service organizations. Explosions can occur when ignition is delayed after fuel is sprayed on the dryer drum burner of the aggregates during the production of ASCON. A physical explosion can occur in the storage tank when environmental purification facilities suddenly work strongly to remove air pollutants or bad smells during the heating of asphalt in an asphalt storage tank. In addition, explosions can occur when fires such as welding is performed in the asphalt storage tank.

• Journal of Pharmacopuncture
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• v.19 no.4
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• pp.350-358
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• 2016

Objectives: This study was carried out to analyze the single dose toxicity of ShinEumHur (SEH) pharmacopuncture injected into the muscles of Sprague-Dawley rats. Methods: The SEH pharmacopuncture was made in a clean room at the Korean Pharmacopuncture Institute (K-GMP). After the mixing process with sterile distilled water had been completed, the pH was controlled to between 7.0 and 7.5. All experiments were conducted at Biotoxtech, an institution authorized to perform non-clinical studies under the Good Laboratory Practice (GLP) regulations. Sprague-Dawley rats were chosen for the pilot study. Doses of SEH pharmacopuncture, 0.25, 0.5 and 1.0 mL, were administered to the experimental groups, and a dose of normal saline solution, 1.0 mL, was administered to the control group. We examined the survival rate, weights, clinical signs, mean hematology parameters, mean clinical chemistry, necropsy and histopathological findings. This study was conducted under the approval of the Institutional Animal Ethics Committee. Results: No deaths or abnormalities occurred in any of the four groups. No significant changes in weight, hematological parameters or clinical chemistry between the control group and the experimental groups were observed. To check for abnormalities in organs and tissues, we used microscopy to examine representative histological sections of each specified organ; the results showed no significant differences in any of the organs or tissues. Conclusion: The above findings suggest that treatment with SEH pharmacopuncture is relatively safe. Further studies on this subject are needed to yield more concrete evidence.

• Journal of Pharmacopuncture
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• v.13 no.4
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• pp.5-41
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• 2010

Objectives: This study was performed to analyse four week repeated dose toxicity of Sweet Bee Venom(Sweet BV) extracted from the bee venom in Beagle dogs. Methods: All experiments were conducted under the regulations of Good Laboratory Practice (GLP) at Biotoxtech Company, a non-clinical study authorized institution. Male and female Beagle dogs of 5-6 months old were chosen for the pilot study of four week repeated dose toxicity of Sweet BV which was administered at the level of 0.56mg/kg body weight which is eighty times higher than the clinical application dosage as the high dosage, followed by 0.28 and 0.14mg/kg as midium and low dosage, respectively. Equal amount of excipient(normal saline) to the Sweet BV experiment groups was administered as the control group every day for four weeks. Results: 1. No mortality was witnessed in all of the experiment groups. 2. All experiment groups were appealed pain sense in the treating time compared to the control group, and hyperemia and movement disorder were observed around the area of administration in all experiment groups, and higher occurrence in the higher dosage treatment. 3. For weight measurement, Neither male nor female groups showed significant changes. 4. In the urine analysis, CBC and biochemistry didn't show any significant changes in the experiment groups compared with control group. 5. For weight measurement of organs, experiment groups didn't show any significant changes compared with control group. 6. To verify abnormalities of organs and tissues, thigh muscle which treated with Sweet BV, cerebrum, liver, lung, kidney, and spinal cords were removed and conducted histologocal observation with H-E staining. In the histologocal observation of thigh muscle, cell infiltration, inflammatory, degeneration, necrosis of muscle fiber, and fibrosis were found in both thigh tissue. And the changes were depend on the dose of Sweet BV. But another organs were not detected in any abnormalities. 7. The proper high dosage of Sweet BV for the thirteen week repeated test in Beagle dogs may be 0.28mg/kg in one time. Conclusion: Above findings suggest that Sweet BV is relatively safe treatment medium. Further studies on the subject should be conducted to yield more concrete evidences.

• Clean Technology
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• v.17 no.2
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• pp.85-96
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• 2011

Self-healing materials are a class of smart materials that have the structurally incorporated ability to repair damage caused by mechanical usage over time. A material (polymers, ceramics, metals, etc.) that can intrinsically correct damage caused by normal usage could lower production costs of a number of different industrial processes through longer part lifetime, reduction of inefficiency over time caused by degradation, as well as prevent costs incurred by material failure. The recent announcement from Nissan on the commercial release of scratch healing paints for use on car bodies has gained public interest on such a wonderful property of materials. This article is a second part of healing materials dealing with inorganic engineering materials such as metals, ceramics, and concrete. The healing mechanisms developed for the inorganic materials are to be discussed with the future prospect.