경주권역으로의 대기오염물질 유입현황과 석조문화재에 미치는 영향

정종현,손병현,김현규,최원준,남철현,Jung, Jong-Hyeon,Shon, Byung-Hyun,Kim, Hyun-Gyu,Choi, Won-Joon,Nam, Chul-Hyun 한국환경보건학회 2005 한국환경보건학회지 Vol.31 No.5

In this study, we focused on the geographical and the meterological conditions, the atmospheric examination, the soil contents and compositions in order to establish cultural properties conservation plan in Gyeongju and its surroundings. Also, the transport route with environmental contaminants in Ulsan and Pohang was examined. The results could be summarized as follows ; Air pollutant and environmental contaminant was transported by two types of winds. One is induced by local winds, the other is induced by synoptic winds. Air contaminant transported from coastal regions to inland regions were associated with wind velocity. Gyeongju had good atmospheric conditions, i.e. $SO_2\;0.009{\sim}0.011ppm,\;CO\;0.6{\sim}0.8ppm,\;NO_2\;0.015{\sim}0.020ppm,\;O_3\;0.017{\sim}0.032ppm,\;PM_{10}\;46{\sim}62{\mu}g/m^3\;and\;Pb\;0.034{\sim}0.060{\mu}g/m^3$, which was below environmental air qualify standards and was little lower than those of Pohang and Ulsan. However, Ulsan and Pohang city are located on south-east coast and have many industrial facilities. Hence, air pollution problems become serious issues in Ulsan, Pohang, Busan, Daegu and other cities due to the emission of air pollutants from the various industrial facilities, incinerator and power plants, etc. The soil of Gyeongju had heavy metals conditions, i.e. $Cd\;0.01{\sim}0.08mg/kg,\;Cu\;N.D{\sim}2.39mg/kg,\;As\;N.D{\sim}0.07mg/kg,\;Hg\;N.D{\sim}0.15mg/kg,\;Pb\;0.49{\sim}1.39mg/kg,\;Cr^{+6}\;0.02{\sim}0.42mg/kg,\;Fe\;0.74{\sim}1.55mg/kg,\;Mn\;0.11{\sim}0.49mg/kg\;and\;Zn\;1.11{\sim}3.56mg/kg$. However, pH value of soil had range of $4.12{\sim}7.45$. The results showed that high pH concentration of soil could occur due to air pollution diffusion and environmental contaminant transport at Ulsan and Pohang city.

유리단국부의치(遊離端局部義齒) 사용시(使用時) 지태치(支台齒) 동요(動搖)에 대한 Splingting의 효과(效果)(II)

정종현,Jung, Jong-Hyun 대한치과기공학회 1986 대한치과기공학회지 Vol.8 No.1

The effect of splinting on aqbutment tooth distal movement was performed in vitro study. An acrylic resin mandibular model with missing 2nd premolars, molars and a removable partial denture framework were constructed. The roots of the canines, 1st premolars and edentulous ridges were coated with silicone rubber. A modified Ney Surveyor was used for vertical load appkication, and abutment tooth distal movement were measured with a dial gauge with four conditions of splinting methods were tested by applying unilateral vertical loadings. The results are follows; 1. The magnitude of abutment tooth distal movement on the non-load side was less 40$\sim$69% than that occurred on the load side. 2. On the load side, reducing effect of splinting on abutment tooth movement in the condition of load side double abutment(30%), non-load side double abutment(10%), double abutments of both sides(40%) was compared with single abutments of both sides. 3. On the non-load side, reducing effect of splinting on abutment tooth movement in the condition of load side double abutment(5%), non-load side double abutment(22%), double abutments of both sides(59%) was compared with single abutments of both sides. 4. The magnitude of abutment tooth distal movement in the condition of double abutments of both sides was less 40$\sim$59% than that in the condition of single abutments of both sides.

IFC를 이용한 기본설계단계 철근배근의 표현

정종현,김치경,이재철,김지현,김민수,Jung, Jong-Hyun,Kim, Chee-Kyeong,Lee, Jae-Cheol,Kim, Ji-Hyun,Kim, Min-Soo 대한건축학회 2012 대한건축학회논문집 Vol.28 No.1

In recent years, BIM has been applied to many building projects. However, IFC, which is the core technology of data exchange in BIM, has not been used widely. In particular, IFC has almost never been used to represent rebars in RC structures. This is because the lack of understanding and utilization strategy for data model of IFC on rebars. The purpose of this study is to store and manage the data on rebars using IFC at the schematic design stage. For this, we investigated the data to represent rebars for RC members, such as beam, column, wall, and slab at the schematic design stage. And, we analyzed the data model of IFC on rebars at the schematic design stage. Based on these investigation and analysis on data, we proposed the strategy for utilization of the data model of IFC on rebars. Finally, for verification, we generated a sample IFC file to represent the rebars of a simple RC structure according to the proposed strategy and imported the sample IFC file into the software, which we developed for this study. Based on the results of the import, we concluded that the data on rebars can be stored and managed using the proposed strategy for utilization of the data model of IFC on rebars.

해수와 대기오염물질이 석조문화재에 미치는 영향: 감은사지 삼층석탑을 중심으로

정종현,손병현,정민호,임헌호,김경원,김현규,Jung, Jong-Hyeon,Shon, Byung-Hyun,Jung, Min-Ho,Leem, Heon-Ho,Kim, Kyung-Won,Kim, Hyun-Gyu 한국환경보건학회 2007 한국환경보건학회지 Vol.33 No.4

The effect of seawater and air pollutants on the three-story stone pagodas on Gameunsa Temple Site have been studied in order to establish conservation basic plan. Also, an experimental study has been conducted to evaluate the effect of seawater salt and air pollutants on the weathering of granite. The results could be summarized as follows. Because the three-story stone pagodas on Gameunsa Temple Site are located outdoors, the external appearance has been largely deteriorated due to natural and artificial factors such as typhoon, wind, microorganisms, moisture, extreme change in temperature, air pollutants, and seawater, etc. When G.J fresh granite was dipped into the seawater, dissolution rate of three minerals (Mg, Ca, and K) are increased linearly until about 40 days and then increased abruptly. After seawater dipping experiments, the mineral compositions of the granite surface were lower then that of the G.J fresh granite but Poisson's ratio and absorption ratio were slightly increased. Therefore, from these results we can say that stone cultural properties could be weathered by seawater and air pollutants and it's considered being a meaningful experiment to study the conservation method of stone cultural properties from seawater.

울산 지역 학교의 휘발성유기화합물 평가

정종현,이사우,피영규,Jung, Jong-Hyeon,Lee, Sa-Woo,Phee, Young-Gyu 한국학교보건학회 2012 韓國學校保健學會誌 Vol.25 No.1

Purpose: The purpose of this study was to investigate the concentrations of volatile organic compounds at elementary, middle, and high schools in Ulsan and its surroundings. Methods: To assess the hazardous chemicals of the 66 classrooms in the 22 schools, the 6 volatile organic compounds such as TVOCs (Total Volatile Organic Compounds), benzene, toluene, xylene, ethyl benzene and stylene were measured and analyzed from the beginning of May to the end of December, 2009. Results: The mean concentrations of TVOCs in the elementary schools were higher than those of middle and high schools, and multi-purpose classrooms was higher than that in general ones. The benzene and toluene level in schools in Dong-Gu in the vicinity of assorted industrial complexes was higher than that of schools located in other districts around the Ulsan Metropolitan Area. Conclusion: In case of schools in Ulsan Metropolitan Area, elementary school, schools in Dong-Gu, and multipurpose classrooms over general classrooms should be given a high priority for the management of volatile organic compounds.

생체용 Ti-Zr-Pd계 합금의 양극분극특성

정종현,Jung, Jong-Hyun 대한치과기공학회 2001 대한치과기공학회지 Vol.23 No.1

For biomedical applications. Ti-X%Zr-Y%Pd(X: $10{\sim}20$, Y:0.2 or 0.4) based alloys not containing harmful Al and V were newly designed, and polarization curves for their alloys were measured at $37^{\circ}C$ in 5% HCl solution in order to understand effects of Zr on the corrosion. From the results of anodic polarization behavior, it was found that the corrosion resistance increased with increasing Zr content. The results show their potential to develope Ti-based alloys for biomedical materials. The Ti-20%Zr-0.2%Pd alloy shows excellent corrosion resistance and was superior to those of the Ti. Ti-6%Al-4%V ELI alloy, Co-30%Cr-6%Mo alloy and STS 316L stainless steel.

소비자 기호 다변화를 위한 돼지 품종 개발

정종현,Jung, Jong Hyun 한국축산식품학회 2017 축산식품과학과 산업 Vol.6 No.1

치과용 Co-Cr 합금의 제성질에 미치는 Boron과 Silicon의 영향

정종현,Jung, Jong-Hyun 대한치과기공학회 1992 대한치과기공학회지 Vol.14 No.1

This paper aims to investigate the effect of B and Si upon the mechanical properties, microstructure and corrosion resistance of Co-Cr base alloy. Ten groups of alloy ingot ingot with various contents of B and Si were remelted by high frequency electrical induction furnace and cast into tensile specimen of ADA Specification No. 14 Tensile and hardness test were carried out by Amsler and Rockwell hardness tester(R-30N), respectively. The microstructures of specimen were observed by SEM. The results obtained are summarized as follows : 1. As B content is increased, tensile strength, yield strength and Rockwell hardness number(R-30N) are also increased significantly, while the elongation is decreased significantly. 2. As Si contect os increased, no significant chang in tensile strength is noticed, yield strength is slightly decreased, but Rockwell hardness number(R-30N) is moderately in creased, Elongation marks maxium value with 1% Si content while with more than 1% Si it is decreased. 3. As B content is increased corrosion resistance is decreased and is at best with 1.5% B content. Corrosion resistance is increased with the increase of Si content and the alloys with Si over 3.0% showed corrosion resistance. 4. As B content increased, precipitates are increased in number at grain boundaries. The grain size tends to become coarse with the increase of Si content. 5. Co rich-Cr alloy is present through matrix whereas at the grain boundaries Cr base precipitates are primarily formed.

열중합(熱重合) 레진의치상(義齒床) 수리시(修理時) 파절면(破折面)에 대한 처리방법(處理方法)이 수리 후 Transverse strength에 미치는 영향(影響)

정종현,Jung, Jong-Hyun 대한치과기공학회 1990 대한치과기공학회지 Vol.12 No.1

The purpose of this study was to investigate the effect of surface tretment on strength of denture repair as influenced by repair resin. Specimens were fabricated from VERTEX heat cured resin. Rectangular specimens($60\times10\times3mm$) were prepared according to the manufacturer's instruction for mixing and packing the resin into molds. Two methods of surface treatment were used and two methods of repair were also tested. The transverse strength of the resin was measured before repair and after repair by AUTOGRAPH testing machine. Six specimens of each category were prepared for testing for a total of 24 specimens. The mean value of the percent of recovery was calculated from the percent of recovery for six specimens. The results were as follows : 1. The mean value of the percent of recovery of each category makes a significant difference statistically one another(p<0.01), and "C" category, chloroform solvent-heat cured resin, has a better effect on repair srength than any other. 2. When no chloroform is used to treat the fractured surface there is no significant difference between the mean values of the percent of recovery influenced by the self curing resin and heat cured resin. But, when chloroform is used there is a significant difference between the two repair resins(p<0.01). 3. When self curing resin repair is used there is no significant difference between repair with and without the surface treatment of chloroform. But, when heat cured resin repair is used the use of chloroform treatment become significant statistically (p<0.01).

전자론에 의한 생체용 Ti-Zr-Nb-Pd계 합금의 내식성 평가

정종현,선금주,Jung, Jong-Hyun,Sun, Gum-Ju 대한치과기공학회 2004 대한치과기공학회지 Vol.26 No.1

In order to understand alloying effects on the corrosion resistance of Ti-(10$\sim$20)%Zr-(2$\sim$8%)Nb-0.2%Pd alloys, Polarization curves were measured at 5%HCI solution. The results were interpreted in terms of two parameters obtained by the molecular orbital calculation ; one is the bond order($B_{\circ}$) and the other is the metal d-orbital level($M_{d}$). $B_{\circ}$ is a measure of the strength of covalent bonds between titanium and alloying elements. $M_{d}$ is correlative with the electronegativity of elements. It was found that increasing of Zr and Nb with higher $B_{\circ}$ values showed a lower critical anodic current density in the polarization curve and hence higher corrosion resistance. On the other hand, increasing of Zr and Nb with higher $M_{d}$ values showed a higher corrosion resistance.