• 동의신경정신과학회지
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• 제14권2호
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• pp.79-94
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• 2003

This study aimed to evaluate the anti-stress effects of Palmuljungjiwon and Gamipalmuljungjiwon on the contents of monoamines in the regional brain of mice immobilized stress. The experimental animals were immobilized in stress cylinder(height: 15cm, diameter: 3cm) for 15 minutes, and administered of Palmuljungjiwon(1.14mg/l0g) and Gamipalmuljungjiwon(1.17mg/10g) water extract for 7 days before stress. The monoamines contents were measured by HPLC method in various part(frontal cortex, hypothalamus, corpus striatum and hippocampus) of mice brain. The following results were obtained : 1. In frontal cortex, the contents of norepinephrine a little decreased in all of the administered group, but the statistical significance was not recognized. The contents of dopamine were decreased with statistical significantly in Gamipalmuljungjiwon administered group compared to control group. The contents of serotonin were decreased with statistical significance in PalmulJungjiwon administered group compared to control group. 2. In hypothalamus, the contents of norepinephrine were decreased with statistical significantly in all of the administered group compared to control group. The contents of dopamine were decreased in all of the administered group compared to control group, but the statistical significance was not recognized. The contents of serotonin were decreased with statistical significantly in Gamipalmuljungjiwon administered group compared to control group. 3. In corpus striatum, the contents of norepinephrine were decreased with statistical significantly in Gamipalmuljungjiwon administered group compared to control group. The contents of dopamine were decreased in all of the administered group compared to control group, but the statistical significance was not recognized. The contents of serotonin were decreased with statistical significance in all of the administered group compared to control group 4. In hippocampus, the content of norepinephrine and dopamine a little decreased in all of the administered group, but the statistical significance was not recognized. The contents of serotonin were decreased with statistical significance in all of the administered group compared to control group. In conclusion, this study shows that Palmuljungjiwon and Gamipalmuljungjiwon are significantly effective on reducing and preventing stress in mice.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.54-65
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• 1997

To quantify the LII signals from soot particle of flames in diesel engine cylinder, a new method has been proposed for correcting LII signal attenuated by soot particles between the measuring point and the detector. It has been verified by an experiment on a laminar jet ethylene-air diffusion flame. Being proportional to the attenuation, the ratio of LII signal at two different detection wavelengths can be used to correct the measured LIIsignal and obtain the unattenuated LII signal, from which the soot volume fraction in the flame can be estimated. Both the 1064-nm and frequency-doubled 532-nm beams from the Nd : YAG laser are used. Single-shot, one-dimensional(1-D) line images are recorded on the intensified CCD camera, with the rectangular-profile laser beam using 1-mm-diameter pinhole. Two broadband optical interference filters having the center wavelengths of 647 nm and 400 nm respectively and a bandwidth of 10 nm are used. This two-wavelength correction has been applied to the ethylene-air coannular laminar diffusion flame, previously studied on soot formation by the laser extinction method in this laboratory. The results by the LII measurement technique and the conventional laser extinction method at the height of 40 nm above the jet exit agreed well with each other except around outside of the peaks of soot concentration, where the soot concentration was relatively high and resulting attenuation of the LII signal was large. The radial profile shape of soot concentration was not changed a lot, but the absolute value of the soot volume fraction around outside edge changed from 4ppm to 6.5 ppm at r=2.8mm after correction. This means that the attenuation of LII signal was approximately 40% at this point, which is higher than the average attenuation rate of this flame, 10~15%.

• 대한치과기공학회지
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• 제38권3호
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• pp.135-142
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• 2016

Purpose: The aim of this research was to evaluate the influence of different surface treatments on the shear bond strength of zirconia ceramic to composite resin. Methods: Seventy two cylinder-shape (diameter: 5 mm; height: 12 mm) blocks of experimental industrially manufactured Y-TZP ceramic were abraded with $125{\mu}m\;Al_2O_3$ particles and randomly divided into 4 groups. All the materials were categorized as group Gc(control group - composite resin veneering on zirconia surface), Gr - composite resin veneering after surface treatment of Rocatec system (3M ESPE, Seefeld, Germany) group; Gz - composite resin veneering after surface treatment of Zirconia primer (Z-primer, Bisco, U.S.A) group; Gm - composite resin veneering after surface treatment of zirconia primer (Monobond plus, ivoclar vivadent AG, Liechtenstein) group. Two different zirconia primers and Rocatec system were used to zirconia cylinders (n=16) onto the zirconia surface. Zirconia specimens, polished and roughened, were pretreated and composite bilayer cylinders bonded using conventional adhesive techniques. Results: Shear bond strengths were analyzed using single-factor ANOVA(p<0.05). Bond strength values achieved after airbone particle abrasion and zirconia surface pre-treatments(p<0.05). Conclusion: Shear bond strength tests denmonstrated that zirconia primer is a viable method to improved bond strength between zirconia ceramic core and veneering composites.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.809-812
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• 2008

현재 KS와 ASTM, BS 등에 규정되어 있는 블리딩 시험방법은 수직 원통 용기에 일정량의 모르타르를 채우고 시간이 경과함에 따라 변화하는 블리딩량과 부피팽창을 측정하는 방법이다. 블리딩 측정 시간은 KS에서는 3시간과 20시간으로 규정되어 있으며, ASTM과 BS에서는 블리딩은 타설 후 3시간에 측정하고 부피변화는 24시간 후에 측정하는 것으로 규정되어 있는 등 시험에 비교적 많은 시간이 소요되는 특징이 있다. 모르타르의 블리딩을 측정하는 또 다른 시험법으로 가압거름을 이용한 방법이 있다. 이는 압력을 가하여 미세한 직경의 공극을 가지는 필터를 통과하는 물의 양을 측정하는 방법으로 간접적으로 블리딩양을 예측하는 방법이다. 1971년 Schupack에 의해 고안된 방법으로 빠른 시간에 결과를 측정할 수 있다는 장점이 있는 반면, 아직 연구가 미흡하여 실험결과와 블리딩양과의 상관관계등에 대한 정립이 미흡한 상태이다. 따라서, 본 연구에서는 가압거름방법에 의한 시험 방법과 기존의 시험 방법을 비교하여 가압거름방법에 대한 타당성을 검증하고, 블리딩 양에 대한 상관관계를 도출하였다.

• 대한치과보철학회지
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• 제41권2호
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• pp.243-257
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• 2003

The purpose of this study was to search the influences of the increase of the contents of sodium alginate in the experimental alginates on the some mechanical properties. 3 commercial alginates were selected for the purpose of comparison of the results of experiments. 7 experimental alginates were manufactured with the rise of contents of sodium alginate from 8.8% to 18.3% with the decrease of contents of diatomaceous earth and with the constant contents of calcium sulfate 12.5%. sodium phosphate 2.2%, zinc fluoride 2.0%. Splitable metal mold with 12.5mm diameter and 20.0mm height was filled with mixed alginate to prepare the cylinder shaped specimens. Strain in compression, elastic recovery, compressive strength were tested using the ISO specification number 1563, alginate impression material. Experimental groups were 7, and 10 specimens were used for each test items and each groups. Following results were obtained ; 1. Strain in compression was decreased with the increase of sodium alginate contents (p=0.0077, r2 = 0.6302). 2. Elastic recovery was decreased with the increase of sodium alginate contents but was not significant(p=0.0639, r2=0.7449). 3. Compressive strength was increased with the increase of sodium alginate contents (p<0.0001, r2 = 0.9617). These results mean that the increase of sodium alginate contents make alginate harder but may result the increased permanent deformation.

• Journal of Radiation Protection and Research
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• 제18권2호
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• pp.17-25
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• 1993

액체섬광 계수기에 대한 $^3H,\;^{14}C,\;^{36}Cl$의 베타선 스펙트럼의 시뮬레이션을 Monte Carlo 법으로 수행하였다. 베타선의 손실에너지는 'continuous slowing down approximation(CSDA)' 모형으로부터 구하였다. 순 베타방출 핵종이 균일하게 용해되어 있는 섬광용액은 $1.25cm{\times}3.5cm$의 원통형 geome try로 가정하였다. $^{14}C,\;^{36}Cl$에 대한 계산결과는 계수효율의 경우 실험 값과 2%의 범위 내에서 잘 일치하였으나 $^3H$에 대해서는 상당한 편차를 나타내었다. 이는 저 에너지 베타선에 대한 섬광용액 자체의 quenching 효과에 기인하는 것으로 판단된다.

• Restorative Dentistry and Endodontics
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• 제43권2호
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• pp.19.1-19.10
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• 2018

Objectives: This study investigated the effect of continuous application of 10-methacryloyloxydecyldihydrogen phosphate (MDP)-containing primer and luting resin cement on bond strength to tribochemical silica-coated yttria-stabilized tetragonal zirconia polycrystal (Y-TZP). Materials and Methods: Forty bovine teeth and Y-TZP specimens were prepared. The dentin specimens were embedded in molds, with one side of the dentin exposed for cementation with the zirconia specimen. The Y-TZP specimen was prepared in the form of a cylinder with a diameter of 3 mm and a height of 10 mm. The bonding surface of the Y-TZP specimen was sandblasted with silica-coated aluminium oxide particles. The forty tribochemical silica-coated Y-TZP specimens were cemented to the bovine dentin (4 groups; n = 10) with either an MDP-free primer or an MDP-containing primer and either an MDP-free resin cement or an MDP-containing resin cement. After a shear bond strength (SBS) test, the data were analyzed using 1-way analysis of variance and the Tukey test (${\alpha}=0.05$). Results: The group with MDP-free primer and resin cement showed significantly lower SBS values than the MDP-containing groups (p < 0.05). Among the MDP-containing groups, the group with MDP-containing primer and resin cement showed significantly higher SBS values than the other groups (p < 0.05). Conclusions: The combination of MDP-containing primer and luting cement following tribochemical silica coating to Y-TZP was the best choice among the alternatives tested in this study.

• 에너지공학
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• 제23권2호
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• pp.13-20
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• 2014

헬리컬 코일이 덕트 내부에 있을 때, 기울기에 따른 자연대류 열전달을 실험적으로 측정하였다. 고부력 조건을 구현하기 위하여 유사성에 기초하여 열전달 실험을 대신하여 물질전달 실험을 수행하였다. RaD 수 $4.55{\times}10^6$에서, 턴(Turn) 수를 1~10, P/D를 1.3~5, 헬리컬 코일의 기울기를 $0^{\circ}{\sim}90^{\circ}$까지 변화시켰다. 헬리컬 코일의 턴 수가 1일 때, 측정된 $Nu_D$ 수는 McAdams의 수평관 자연대류 열전달 상관식과 거의 일치하였다. 기울어진 덕트 내 헬리컬 코일의 자연대류 열전달은 피치, 턴 수, 덕트 높이에 따라 복합적으로 변화하였고 이는 속도 효과, 굴뚝 효과, 예열 효과로 분석되었다. 본 연구의 결과는 Compact heat exchanger에서의 자연대류 열전달에 대한 현상학적 분석에 기여한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.365-365
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• 2010

Similar to the superhydrophobic surfaces of lotus leaf, water strider leg is attributed to hierarchical structure of micro pillar and nano-hair coated with low surface energy materials, by which water strider can run and even jump on the water surface. In order to mimick its leg, many effort, especially, on the fabrication of nanohairs has been made using several methods such as a capillarity-driven molding and lithography using poly(urethane acrylate)(PUA). However most of those effort was not so effective to create the similar structure due to its difficulty in the fabrication of nanoscale hairy structures with hydrophobic surface. In this study, we have selected a low surface energy polymeric material of polytetrafluoroethylene (PTFE, or Teflon) assisted with surface modification of CF4 plasma treatment followed by hydrophobic surface coating with pre-cursor of hexamethyldisiloxane (HMDSO) using a plasma enhanced chemical vapor deposition (PE-CVD). It was found that the plasma energy and duration of CF4 treatment on PTFE polymer could control the aspect ratio of nano-hairy structure, which varying with high aspect ratio of more than 20 to 1, or height of over 1000nm but width of 50nm in average. The water contact angle on pristine PTFE surface was measured as approximately $115^{\circ}$. With nanostructures by CF4 plasma treatment and hydrophobic coating of HMDSO film, we made a superhydrophobic nano-hair structure with the wetting angle of over $160^{\circ}C$. This novel fabrication method of nanohairy structures has been applied not only on 2-D flat substrate but also on 3-D substrates like wire and cylinder, which is similarly mimicked the water strider's leg.

• Journal of Advanced Marine Engineering and Technology
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• 제23권2호
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• pp.192-200
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• 1999

This paper describes experimental investigations of helium-air exchange flow through parti-tioned opening. Such exchange flow may occur following rupture accident of stand pipe in high temperature gas cooled reactor. A test vessel with a opening on top of test cylinder is used for experiments. An estimation method of mass increment is developed and applied to measure the exchange flow rate. A technique of flow visualization by Mach-Zehnder interferometer is provided to recognize the exchange flows. Flow measurements are made with partitioned opening for parti-tion rations $H_p/H_1$ in the range 0 to 1 where $H_p$ and $H_1$ are partition length and height of the open-ing respecticely. In the case of $H_p/H_1$ of 0 flow passages of upward flow of the helium and down-ward flow of the air within the opening are unseparated (bidirectional) and the two flows interact exchange flow rate is minimum through range of the partition ratios, Two flow zones i.e. separat-ed(unidirectional)flow zone and unseparated(bidirectional) flow zone exist with increasing the partition. length, The exchange flow rate increases with increasing the separated flow zone. It is found that a maximum exchange flow rate exists at $H_p/H_1$ of 1. As a result fo comparison of the exchange flow rates by changing the partition ration the fluids interaction in the unseparated zone is found to be an important factor on the helium-air exchange flow rate.