• Title/Summary/Keyword: Surface system

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Screening Methods for Plant-Coating Materials and Transpiration Inhibitory Effect of Soybean Oil to Crops (식물 코팅 소재 선발법과 작물들에 대한 콩 오일의 증산 억제 효과)

  • Jung, In Hong;Park, No Bong;Kim, Sang-Yeol;Na, Young-Eun;Kim, Soon-Il
    • Korean Journal of Plant Resources
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    • v.27 no.4
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    • pp.380-391
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    • 2014
  • Plants as well as crops are damaged by a combination of the hot and dry winds that has been a major factor in the reduction of crop production. A means to protect them from damaging conditions is to consider a coating material. In this study, we established laboratory screening methods to find a coating material to protect a crop from rapid transpiration caused by various factors. In a test measuring the weight loss of kidney bean seedlings for 6 days, Avion treatments decreased its weight loss (P=0.05). Owing to long-time spend in completing this assay, we performed a more simple method using a cobalt chloride paper strip, which changes from blue to red colors under water condition. Beewax, guagum, paraffin liquid, soybean oil, and PE-635 gave a waterproofing effect above 37 and 43% at 0.5 and 1 h after treatment, respectively. However, these tested materials did not show significant waterproofing results at 2 h. Although the methods produced reasonable results, a screening method to obtain more objective data is needed. An alternative is to use an instrument that can detect the transpiration of crop leaves. In a preliminary test using barley leaves, a portable photosynthesis system showed transpiration inhibition of 2% soybean oil and 10 times-diluted Avion under field conditions. In another test using the leaves of maize seedlings and apricot tree, 2% liquid paraffin and plant oils such as apricot oil, linseed oil, olive oil, and soybean oil showed significant transpiration inhibition (P=0.05). Especially, paraffin liquid and soybean oil selected from above tests gave good transpiration inhibitory effects against rice at 2%. In addition, the mixture of 2% soybean oil and a spreader showed more elevated inhibition results comparing with soybean oil or the spreader alone indicating that the spreader may be attributed to more uniform diffusion of the hydrophobic material onto the leaf surface of maize seedlings. The hydrophobic material coated physically the stomata and cuticle layers on leaf surfaces of rice. These hydrophobic materials screened in this study are expected to be used as plant coating materials.

Effect of Dynamite Explosion Work Noise on Behavior of Israeli Carp, Cyprinus carpio in the Cage of Aquaculture (양식 향어의 행동에 미치는 발파작업 소음의 영향에 관한 연구)

  • SHIN Hyeon Ok
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.33 no.4
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    • pp.348-355
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    • 2000
  • This paper described the relationship between the behavior of the Israeli carp, Cyprinus carpio and the environmental noise level due to the dynamite explosion work. The experiment was conducted in the cage ($L10{\times}W4{\times}D4 m$) of aquaculture located at Chungjoo Lake, Chechon, in 1997. The fish trajectory was obtained by the telemetry system in which a pulsed ultrasonic pinger ($50 kHz, {\phi}16{\times}L70 mm$) attached to the fish was tracked three dimensionally, and the underwater noise levels were measured. The results of the study were as follows: 1. The underwater noise levels in the normal blasting measured at a distance of 400 m from the source of noise increased by $40 dB (re 1 {\mu}Pa)$ compared to the levels before explosion. The dominant frequency and the increased power spectrum level of the underwater noise by the explosion work were $75 to 100 Hz and 22.9 to 35.3 dB$, respectively. 2. The underwater noise levels in the test blasting measured at a distance of 350 m from the source of noise increased by average $49.5 dB (re 1 {\mu}Pa)$compared to the levels before explosion. 3. The swimming area of the fish was reduced with the time after explosion, and after more than one hour the fish represented the similar swimming area and behavior to the status of right before explosion. 4, The swimming depth layer of the fish was most of the case at the sea surface less than 1,0 m except during explosion or right after of it. But the fish swam downward when an external stimulus like the explosion noise was given to the fish. 5. The average swimming speeds of the fish before, during and after the works were about 1.2 times, 1.9 times and 1.0 times of the body length, respectively, and the speed of the fish with explosion was faster 1.6 times than the speed without of that. Consequently, the explosion noise levels measured by this study were sufficiently high to affect the fish, and the heavy shock by the explosion works could produce a considerable unfavorable effects to the fish.

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Parkin Interacts with the PDZ Domain of Multi-PDZ Domain Protein MUPP1 (Parkin과 Multi-PDZ Domain Protein (MUPP1) 단백질 간의 PDZ 결합)

  • Jang, Won Hee;Jeong, Young Joo;Choi, Sun Hee;Lee, Won Hee;Kim, Mooseong;Kim, Sang-Jin;Urm, Sang-Hwa;Moon, Il Soo;Seog, Dae-Hyun
    • Journal of Life Science
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    • v.24 no.8
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    • pp.820-826
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    • 2014
  • The localization to specific subcellular sites and the regulation of cell surface receptors and channels are crucial for proper functioning. Postsynaptic density-95/Disks large/Zonula occludens-1 (PDZ)-domain is involved in recognition of and interaction between various proteins, by which the localization and the regulation are mediated. Multi-PDZ domain protein 1 (MUPP1) contains 13 PDZ domains. MUPP1 serves a scaffolding function for structure proteins and signaling proteins, but the mechanism how MUPP1 is stabilized and signalized has not yet been elucidated. We used the yeast two-hybrid system to identify proteins that interact with PDZ domains of MUPP1. We found an interaction between MUPP1 and Parkin. Parkin is an E3 ubiquitin ligase. Loss-of-function mutations of Parkin gene are known to cause an autosomal recessive juvenile parkinsonism. Parkin bound to the $12^{th}$ PDZ domain, but not to other PDZ domains of MUPP1. The C-terminal end of Parkin has a type II PDZ-association motif, which was essential for the interaction with MUPP1 in the yeast two-hybrid assay. When co-expressed in HEK-293T cells, Parkin co-localized with MUPP1. When co-expressed with ubiquitin in HEK-293T cells, MUPP1 has been strongly ubiquitinated by Parkin. These findings collectively suggest that MUPP1 is a novel substrate of Parkin and its function or stability could be modulated by Parkin-mediated ubiquitination.

The Difference of the Cleaning and Wettability-maintaining Efficacy of Lens Care Solution to RGP Lens (관리 용품에 따른 RGP 렌즈의 세척효과 및 습윤성 차이)

  • Kim, Myoung-Hea;Park, Mi-Jung
    • Journal of Korean Ophthalmic Optics Society
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    • v.11 no.1
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    • pp.27-34
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    • 2006
  • We investigated the question whether the efficacy of cleaning tear components on RGP lens and preserving the superior wettability of RGP lens depended on the different type of contact lens care system - RGP lens care solution, SCL care solution, combined solution both for SCL and RGP lens or saline solution. The removal efficacy of the deposited protein was examined by Lowry protein assay and Scanning Electro Microscope(SEM) and residual lipid concentration on RGP lens was determined by High Pressure Liquid Chromatology(HPLC). Wettability was assessed with an equilibrium water-in-air contact angle method. When cared by RGP lens solution, it was demonstrated that 62 percent out of the adhered protein on RGP lens were removed and the removal efficacy of RGP lens solution was not only 4 times than saline solution and the alternative but also higher twice than SCL solution. Contrarily, the SCL solution had the most excellent removal efficacy of the adhered protein on SCL. These results suggest that the cleaning efficacy is thought to be affected by the other factors like the viscosity of care solutions, which mutual contact between RGP lens and care solutions is on the increase due to the viscosity enhancer in RGP lens care solution. RGP lens solution had the greatest removing efficacy to cholesterol and the residual cholesterol concentration was decreased to 50%. It is significant for RGP lens to preserve the superior wettability which means the predictive value for comfortable wearing and it showed that the RGP lens solution offered the most excellent efficacy to maintain the surface wettability. Combined solution both for SCL and RGP lens had weak efficacy of cleaning and maintaining wettability for RGP lens compared to RGP lens care solution.

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A Study on Repetition and Multiplicite of Superhero Comics (슈퍼히어로 코믹의 반복과 다양체적 형식에 관한 연구)

  • Park, Seh-Hyuck
    • Cartoon and Animation Studies
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    • s.28
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    • pp.27-53
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    • 2012
  • American superhero comics are being produced in numerous different forms for multiple, and cross-platform media. In cinema, films based on superhero comics top the list of all time box office records. The same phenomenon of the 'Invasion of Superhero' is duplicated in Korean box office 2012, however, the korean fans are not familiar with the superheroes from the publication which provides the original source of characters and stories for other superhero related media products. Based on observing the multiple and vastness of world building characteristics of superhero comic, this paper attempts to associate the continuous creative nature and the infinite repetition of superheroes and comic texts with the identity of superhero on ontological level. First, chapter 2 examines how one superhero exists in multiple and different worlds individually by utilizing the concept of 'multi-universe' or 'multiverse' in comic texts. Initially, duplicating a superhero on multiple settings and series destroyed continuity and allowed contradiction and paradox confused narrative as a whole, but it also gave chances for comics to be more vibrant and experimental with their stories and characters. Chapter 3 analyzes the superhero comic texts in the light of repetition, concept developed by french philosopher Gilles Deleuze, and make the argument that the superheroes and texts are not repeated to generate surplus of source for economic utilitarian purposes, but it is, first and foremost, a repetition of creativeness and capability. Many concepts introduced by Deleuze in his early masterpiece, $\acute{e}$rence et R$\acute{e}$p$\acute{e}$tition> are taken to support this argument. Mainly, his critical views on generality of the identity and his effort to replace the Plato's system of representation with vibrant creative, and renewal energy of r$\acute{e}$p$\acute{e}$tition. According to Deleuze, repetition is similar concept, if not identical, to what Nietzsche called the 'eternal return' which allows the return of the Overhuman or the Superhuman, and he extends his idea that the returning Overhuman is the singular simulacre which opposes the generalization of identity, in the likes of Plato's Idea. Thus, the superhero's identity is ever changing, ever returning, and ever renewing Overhuman. The superhero must be repeated to fully actualize his/her existence. Also, based on Deleuze's reading of Bergson's texts on the Virtual, the superhero, for example Superman, is actualization of his/her multiplisit$\acute{e}$, the internally multiple, and differentiated variations from itself. These every Supermans' multiplisit$\acute{e}$ shares common memory, past, and duration, thus the Virtual of Superman. Superman becomes himself only by actualizing the movement and differentiation from these multiplisit$\acute{e}$ in his virtual on the surface of reality. On chapter 4, a popular Korean comic book character Oh, Hae-Sung's r$\acute{e}$p$\acute{e}$tition and multiplist$\acute{e}$ are analyzed, and makes comparison to that of Superman to distinguish the repetition from r$\acute{e}$p$\acute{e}$tition, and multiplicit$\acute{e}$ from diversity.

EFFECT OF LIGHT IRRADIATION MODES ON THE MARGINAL LEAKAGE OF COMPOSITE RESIN RESTORATION (광조사 방식이 복합레진 수복물의 변연누출에 미치는 영향)

  • 박은숙;김기옥;김성교
    • Restorative Dentistry and Endodontics
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    • v.26 no.4
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    • pp.263-272
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    • 2001
  • The aim of this study was to investigate the influence of four different light curing modes on the marginal leakage of Class V composite resin restoration. Eighty extracted human premolars were used. Wedge-shaped class Y cavities were prepared on the buccal surface of the tooth with high-speed diamond bur without bevel. The cavities were positioned half of the cavity above and half beyond the cemento-enamel junction. The depth, height, and width of the cavity were 2 mm, 3 mm and 2 mm respectively. The specimens were divided into 4 groups of 20 teeth each. All the specimen cavities were treated with Prime & Bond$^{R}$ NT dental adhesive system (Dentsply DeTrey GmbH, Germany) according to the manufacturer's instructions and cured for 10 seconds except group VI which were cured for 3 seconds. All the cavities were restored with resin composite Spectrum$^{TM}$ TPH A2 (Dentsply DeTrey GmbH, Germany) in a bulk. Resin composites were light-cured under 4 different modes. A regular intensity group (600 mW/${cm}^2$, group I) was irradiated for 30 s, a low intensity group (300 mW/${cm}^2$, group II) for 60 s and a ultra-high intensity group (1930 mW/${cm}^2$, group IV) for 3 s. A pulse-delay group (group III) was irradiated with 400 mW/${cm}^2$ for 2 s followed by 800 mW/${cm}^2$ for 10 s after 5 minutes delay. The Spectrum$^{TM}$ 800 (Dentsply DeTrey GmbH, Germany) light-curing units were used for groups I, II and III and Apollo 95E (DMD, U.S.A.) was used for group IV. The composite resin specimens were finished and polished immediately after light curing except group III which were finished and polished during delaying time. Specimens were stored in a physiologic saline solution at 37$^{\circ}C$ for 24 hours. After thermocycling (500$\times$, 5-55$^{\circ}C$), all teeth were covered with nail varnish up to 0.5 mm from the margins of the restorations, immersed in 37$^{\circ}C$, 2% methylene blue solution for 24 hours, and rinsed with tap water for 24 hours. After embedding in clear resin, the specimens were sectioned with a water-cooled diamond saw (Isomet$^{TM}$, Buehler Co., Lake Bluff, IL, U.S.A.) along the longitudinal axis of the tooth so as to pass the center of the restorations. The cut surfaces were examined under a stereomicroscope (SZ-PT Olympus, Japan) at ${\times}$25 magnification, and the images were captured with a CCD camera (GP-KR222, Panasonic, Japan) and stored in a computer with Studio Grabber program. Dye penetration depth at the restoration/dentin and the restoration/enamel interfaces was measured as a rate of the entire depth of the restoration using a software (Scion image, Scion Corp., U.S.A.) The data were analysed statistically using One-way ANOVA and Tukey's method. The results were as follows : 1. Pulse-Delay group did not show any significant difference in dye penetration rate from other groups at enamel and dentin margins (p>0.05) 2. At dentin margin, ultra-high intensity group showed significantly higher dye penetration rate than both regular intensity group and low intensity group (p<0.05). 3. At enamel margin, there were no statistically significant difference among four groups (p>0.05). 4. Dentin margin showed significantly higher dye penetration rate than enamel margin in all groups (p<0.05).

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MICROLEAKAGE AND SHEAR BOND STRENGTH OF FLOWABLE COMPOSITE RESIN (Flowable Composite Resin의 미세변연누출 및 전단결합강도)

  • 박성준;오명환;김오영;이광원;엄정문;권혁춘;손호현
    • Restorative Dentistry and Endodontics
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    • v.26 no.4
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    • pp.332-340
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    • 2001
  • Flowable composite resin has lower filler content, increased flow, and lower modules of elasticity. It is suggested that flowable composite resin can be bonded to the tooth structure intimately and absorb or dissipate the stress. Therefore, it may be advantageous to use flowable composite resin for the base material of class II restoration and for the class V restoraton. The purpose of this study was to evaluate the microleakage and shear bond strength of four flowable composite resins (Aeliteflo, Flow-It, Revolution, Ultraseal XT Plus) compared to Z100 using Scotchbond Multi Purpose dentin bonding system. To evaluate the microleakage, notch-shaped class V cavities were prepared on buccal and lingual surfaces of 80 extracted human premolars and molars on cementum margin. The teeth were randomly divided into non-thermocycling group (group 1) and thermocycling group (group 2) of 40 teeth each. The experimental teeth of each group were randomly divided onto five subgroups of eight samples (sixteen surfaces). The Scotchbond Multi-Purpose and composite resin were applied for each group following the manufacturer's instructions. the teeth of group 2 were thermocycled five hundred times between 5$^{\circ}C$ and 55$^{\circ}C$. The teeth of group 2 were placed in 2% methylene blue dye for 24 hours, then rinsed with tab water. The specimens were embedded in clear resin, and sectioned longitudinally with a diamond saw. The dye penetration on each of the specimen were observed with a stereomicioscope at $\times$20 magnification. To evaluate the shear bond strength, 60 teeth were divided into five groups of twelve teeth each. The experimental teeth were ground horizontally below the dentinoenamel junction, so that no enamel remained. After applying Scotchbond Multi-Purpose on the dentin surface, composite resin was applied in the shape of cylinder. The cylinder was 4mm in diameter and 2mm in thickness. Shear bond strength was measured using Instron with a cross-head speed of 0.5mm/min. After shear bond strength measurement, mode of failure was evaluated with a stereomicroscope at $\times$30 magnification. All data were statistically analyzed by One Way ANOVA and Student-Newman-Keuls method. The correlation between microleakage and shear bond strength was analyzed by linear regression. The results of this study were as follows ; 1. In non-thermocycling group, the leakage value of Z100 was significantly lower than those of flowable composite resins at the enamel and dentin margin, margin, except that Revolution showed the lower leakage value than that of Z100 at the dentin margin (p<0.05). 2. In thermocycling group, the leakage values of Z100 and Ultraseal XT Plus were lower than those of other subgroup at the enamel and dentin margin, except that Flow-It showed the lower leakage value than that of Ultraseal XT Plus at the dentin margin (p<0.05). 3. The leakage value of Z100 and Ultraseal XT Plus in thermocycling group were not higher than that in non-thermocycling group at the enamel margin. The leakage value of Z100 in thermocycling group was not higher than that in non-thermocycling group at the dentin margin (p<0.05). 4. As for the shear bond strength measurement, there were no statistically significant differences among groups (p<0.05). The shear bond strengths given in descending order were as follows: Z100(16.81$\pm$2.98 MPa), Flow-It(14.8$\pm$4.43 MPa), Aeliteflo(14.34$\pm$3.69 MPa), Revolution(13.46$\pm$4.23 MPa), Ultraseal XT Plus(12.83$\pm$3.16 MPa). 5. Failure modes of all specimens were adhesive failures. 6. There was no correlation between microleakage and shear bond strength.

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반응표면분석에 의한 쇠고기 야채 쌀죽의 이화학적 및 관능적 특성 변화

  • 이용욱;금준석;은종방
    • Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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    • 2003.10a
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    • pp.167.2-168
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    • 2003
  • 현대 사회는 서구적인 식생활의 변화로 인해 조리가 간편하고 조리 시간이 짧은 즉석식품과 영양 기호식품을 동시에 충족시켜주는 음식에 대한 소비가 늘고 있는 실정이다. 또한 최근 미곡의 공급량에 비해서 소비량이 해마다 감소하여 재고미의 증가를 볼 때, 쌀의 새로운 이용방법 모색이 절실히 요망된다. 따라서 쌀의 소비촉진과 현대사회의 소비형태를 접목시켜서 쇠고기와 야채를 이용한 즉석쌀죽을 개발하고자 하였다. 쇠고기, 야채 및 쌀가루를 이용한 soup mix의 최적 배합비를 설정하기 위하여 제조조건에 따라 다르게 제조한 쇠고기 야채 쌀죽의 이화학적 및 관능적 특성에 미치는 변화를 조사하였다. 이때 야채의 배합비에 따른 이화학적 및 관능적 특성을 모니터링 하고자 반응표면분석법 (response surface methodology, RSM)을 이용하였다. 요인변수(Xn)를 쌀의 양에 대한 버섯의 비율 (X$_1$), 당근의 비율 (X$_2$), 대파의 비율 (X$_3$)로 하여 중심합성계획에 따라 17실험구로 구분하여 조리실험을 실시하였고, 반응변수(Yn)는 soup mix를 이용하여 제조한 쇠고기 야채 쌀죽의 이화학적 특성인 색도의 L*값 (Y$_1$), a*값 (Y$_2$), b*값 (Y$_3$), 점도(Y$_4$), 퍼짐성 (Y$_{5}$), 고형분 함량(Y$_{6}$), PH (Y$_{7}$)으로 하였으며 관능적 특성인 색 (Y$_{8}$), 향 (Y$_{9}$), 점성 (Y$_{10}$), 맛 (Y$_{11}$), 전체적인 기호도 (Y$_{12}$)를 종속변수로 하여 회귀분석에 이용하였다. 회귀분석에 의한 모델식의 예측에는 SAS (statistical analysis system)program을 사용하였으며, 3차원 반응표면 분석법으로 해석하였다. 야채의 배합비에 따라 제조한 쇠고기 야채 쌀죽의 물리적 특성인 색도의 L*, a*, b* 값에 대한 반응표면 회귀식의 $R^2$은 각각 0.6098(p> 0.05), 0.8803 (p <0.05), 0.6781(p> 0.05)로서 b값에 있어서 그 유의성이 5%수준에서 인정되어 b값에 미치는 영향이 크다는 것을 알 수 있었다. L*값은 63-68사이로, a*값은 0.13에서 -0.89사이를 b*값은 2-5값 사이에서 변화하여 제조한 죽의 색이 옅은 황색임을 알 수 있었다. 고형분 함량, 퍼짐성과 pH에 대한 $R^2$은 각각 0.4280, 0.5433과 0.2406임을 볼 때 버섯, 당근, 대파의 비율에 따라 제조한 쇠고기 야채 쌀죽의 고형분 함량, 퍼짐성과 pH는 설정된 범위내에서 그 유의성이 인정되지 않아 큰 영향을 미치지 않음을 알 수 있었다. 관능검사 결과, 색과 향에 대한 반응표면 회귀식의 $R^2$은 각각0.6000과 0.7825이고 P-value는 각각 0.4290과 0.0942로서 5% 수준에서 유의한 상관성이 없음을 확인할 수 있었다. 맛과 점성에 대한 $R^2$은 0.8717과 0.8068이고 P-value는 각각 0.0195 (p <0.05)와 0.0612로서 야채의 배합비에 따라 맛에 있어서 유의확률 5%수준에서 그 유의성이 인정되었으며, 전체적인 기호도에 대한 유의성은 $R^2$이 0.8463이고 P-value는 0.0344 (p <0.05)임을 볼 때, 설정된 범위내에서 야채의 배합비에 따라 제조한 쇠고기 야채 쌀죽의 맛과 기호도에 큰 영향을 미치는 것을 알 수 있었다. 그리고 최대 임계점이 버섯의 첨가량은 0.99%, 당근의 첨가량은 0.97%, 대파의 첨가량은 0.59%에서 최적 반응표면을 나타내었다. 이상의 결과로 볼 때, 야채의 배합비에 따른 맛과 전체적인 기호도에 있어서 그 유의성이 5%수준에서 모두 유의한 상관관계를 보였으며, soup mix 제조시 쌀가루 양에 대한 야채의 최적 배합비는 버섯, 당근, 대파에 있어서 각각 0.99, 0.97과 0.59%임을 알 수 있었다.

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The Strength Properties Activated Granulated Ground Blast Furnace Slag with Aluminum Potassium Sulfate and Sodium Hydroxide (칼륨명반과 수산화나트륨으로 활성화된 고로슬래그 미분말의 강도 특성)

  • Kim, Taw-Wan;Hahm, Hyung-Gil
    • Journal of the Korea Concrete Institute
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    • v.27 no.2
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    • pp.95-102
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    • 2015
  • In this paper, the effects of sodium hydroxide (NaOH) and aluminum potassium sulfate ($AlK(SO_4)_2{\cdot}12H_2O$) dosage on strength properties were investigated. For evaluating the property related to the dosage of alkali activator, sodium hydroxide (NaOH) of 4% (N1 series) and 8% (N2 series) was added to 1~5% (K1~K5) dosage of aluminum potassium sulfate ($AlK(SO_4)_2{\cdot}12H_2O$) and 1% (C1) and 2% (C2) dosage of calcium oxide (CaO). W/B ratio was 0.5 and binder/ fine aggregate ratio was 0.5, respectively. Test result clearly showed that the compressive strength development of alkali-activated slag cement (AASC) mortars were significantly dependent on the dosage of NaOH and $AlK(SO_4)_2{\cdot}12H_2O$. The result of XRD analysis indicated that the main hydration product of $NaOH+AlK (SO_4)_2{\cdot}12H_2O$ activated slag was ettringite and CSH. But at early ages, ettringite and sulfate coated the surface of unhydrated slag grains and inhibited the hydration reaction of slag in high dosage of $NaOH+AlK(SO_4)_2{\cdot}12H_2O$. The $SO_4{^{-2}}$ ions from $AlK(SO_4)_2{\cdot}12H_2O$ reacts with CaO in blast furnace slag or added CaO to form gypsum ($CaSO_4{\cdot}2H_2O$), which reacts with CaO and $Al_2O_3$ to from ettringite in $NaOH+AlK(SO_4)_2{\cdot}12H_2O$ activated slag cement system. Therefore, blast furnace slag can be activated by $NaOH+AlK(SO_4)_2{\cdot}12H_2O$.

Tensile Bond Strength of Composite Resin Treated with Er:YAG Laser (Er:YAG 레이저를 활용한 와동형성시 컴포짓 결합강도)

  • Shin, Min;Ji, Young-Duk;Rhu, Sung-Ho;Cho, Jin-Hyoung
    • Journal of Oral Medicine and Pain
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    • v.30 no.2
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    • pp.269-276
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    • 2005
  • This in vitro study evaluated the influence of a flowable composite resin on the tensile bond strength of resin to enamel and dentin treated with Er:YAG laser and diamond bur. 96 Buccal enamel and mid-coronal dentin were laser-irradiated using an Er:YAG laser and treated with diamond bur. Each groups(48) were divided two small groups depends on acid-etching procedure. Light-cure flowable resin(Metafil Flo) and self-cure resin(Clearfil FII New Bond) were used in this study. After surface etching with 37% phosphoric acid and the application of an adhesive system, specimens were prepared with a hybrid composite resin. After 24hours storage in distilled water at 37$^{\circ}C$, all samples were submitted to the tensile bond strength evaluation, using a universal testing machine(Z020, Zwick, Germany). The obtained results were as follows: 1. TBS of acid-etching group were higher than those of non-etching group in both enamel and dentin treated with Er:YAG laser and diamond bur. Laser 'conditioning' was clearly less effective than acid-etching. Moreover, acid etching lased enamel and dentin significantly improved the microTBS of M-Flo. 2. In enamel, TBS of laser-irradiated group were lower than those of bur-prepared group. However, in flowable resin subgroup, there were not differed those between two groups in dentin. 3. In laser-treated group, TBS of flowable composite resin were higher than those of self-curing resin in dentin, however, there was no difference in enamel. From this study, we can conclude that the self- and light-cure composite resin bonded significantly less effective to lased than to bur-cut enamel and dentin, and that acid-etch procedure remains mandatory even after laser ablation. We suggest that Er:YAG laser was useful for preparing dentin cavity with flowable resin filling.