• 구강회복응용과학지
• /
• 제16권3호
• /
• pp.197-210
• /
• 2000

Surface roughness is one of implant surface topography and it's found that surface roughness characterizations, such as surface energy, oxide layer thickness and its chemical composition, are closely correlated if the roughness is changed. Several studies showed the importance of analyzing surface structure so the surface structure of thread implant was analyzed to measure the implant quality exactly. In this study, surface roughness of 4 implants - MK $II^{(R)}$(Nobel Biocare), $RBM^{(R)}$(Life-Core, USA), $Osseotite^{(R)}$(3i, USA), $TPS^{(R)}$(Life-Core, USA) - were measured using $Accura^{(R)}$ and 40 implants were installed into 4 sets of ten bovine ribs based on the parameters from the measurements. From this test, the following conclusions for the initial stability were drawn by measuring and comparing RFA, Periotest Value (PTV), Removal Torgue Value (RTV). 1. $R_a$ value in surface roughness measurement was increasing by the order of $MKII^{(R)}$, $Osseotite^{(R)}$, $RBM^{(R)}$, $TPS^{(R)}$ and $R_q$ value was the same order. 2. $R_q$ value in each section was observed to increase by the order of $MKII^{(R)}$, $Osseotite^{(R)}$, $RBM^{(R)}$, $TPS^{(R)}$ in top and $MKII^{(R)}$, $RBM^{(R)}$, $Osseotite^{(R)}$, $TPS^{(R)}$ in mid-section but the value of $MKII^{(R)}$ bottom was the lowest, followed by $Osseotite^{(R)}$, $RBM^{(R)}$ and $TPS^{(R)}$. 3. RFA increased by the order of $RBM^{(R)}$(7042Hz), $MKII^{(R)}$(7047Hz), $Osseotite^{(R)}$(7076Hz), $TPS^{(R)}$(7168Hz) and there was no significance between each group. 4. PTV was increasing by the order of $MKII^{(R)}$(-1.62), $TPS^{(R)}$(-1.92), $Osseotite^{(R)}$ & $RBM^{(R)}$(-2.08) and there was no significance, either. 5. Removal torque in RTV measurement showed the increasing order of $MKII^{(R)}(5.31kgf{\cdot}cm)$, $Oeeotite^{(R)}(5.71kgf{\cdot}cm)$, $TPS^{(R)}(5.92kgf{\cdot}cm)$ and $RBM^{(R)}(7.24kgf{\cdot}cm)$ and there was no significance among groups. Above observations explains that surface roughness does not make any impact on the initial stability of implants installation.

• Food Science and Biotechnology
• /
• 제17권1호
• /
• pp.66-71
• /
• 2008

A total of 284 milled rice (MR) marketed in Korea were analyzed for grading characteristics (head rice, broken kernels, chalky kernels, and damaged kernels%), color characteristics (L-, a-, b-values, and whiteness), protein content (%), and the cooked rice (CR) sensory quality to investigate the key characteristics affecting the overall sensory quality of rice marketed in Korea. Relatively high correlation with the overall sensory quality of the CR was found in color characteristics such b-value of the CR (r=-0.779) and MR (r=-0.545), the a-value of the CR (r=0.513), and the whiteness (r=0.298) of the MR, compared to protein (r=-0.150), and the moisture (r=0.158) contents of the MR and the percentage of head rice (r=0.195). Partial least squares (PLS) regression of the CR b-value with various characteristics of the MR showed that CR b-value was increased with MR b-value effectively, followed by protein content, damaged kernels, chalky kernels, and colored kernels of MR while it was decreased with whiteness and moisture content for the MR.

• Restorative Dentistry and Endodontics
• /
• 제24권1호
• /
• pp.233-239
• /
• 1999

Recently, a second generation composite resin system(ceromer) was introduced with significantly improved mechanical properties. The purpose of this study was to compare a ceromer with the other restorative materials and to assess its clinical usefulness. In this study, we used four restorative materials : amalgam (BESTALOY$^{(R)}$), indirect composite resin (Clearfil CR Inlay$^{(R)}$), ceromer (Targis$^{(R)}$) and ceramic (Vintage$^{(R)}$). And then we devided into four groups. The materials of each group were as follows : Amalgam group : BESTALOY$^{(R)}$ (Dong Myung Dental Industrial Co.) Composite Resin group : Clearfil CR Inlay$^{(R)}$ (Kuraray) Ceromer group : Targis$^{(R)}$ Dentin (Ivoclar-Vivadent) Ceramic group : Vintage$^{(R)}$ (Shofu Inc.) According to the above classification, we made samples through the polymerization of BESTALOY$^{(R)}$, Clearfil CR Inlay$^{(R)}$ and Targis$^{(R)}$ with separable cylindrical metal mold and firing of Vintage$^{(R)}$ in a investment mold. And then, we measured and compared the value of compressive strength, diametral tensile strength and Vicker's microhardness of each sample. The results were as follows : 1. Amalgam showed the highest value of compressive strength (390.37${\pm}$42.22MPa) and the value of ceromer was somewhere between ceramic and indirect composite resin. There were significant differences among the experimental groups(p<0.001). 2. Indirect composite resin showed the highest value of diametral tensile strength (74.21${\pm}$15.33MPa) and there was no significant difference with ceromer. Ceromer was higher diametral tensile strength than amalgam and ceramic (p<0.001). 3. Ceramic showed the highest value of microhardness (538.44${\pm}$37.38Hv) and the value of ceromer was somewhere between ceramic and indirect composite resin. There were significant differences among the experimental groups (p<0.001).

• 한국산학기술학회논문지
• /
• 제17권7호
• /
• pp.63-76
• /
• 2016

R&D 연구 투자의 문제점의 하나는 불확실성이 크다는 점이다. 이러한 불확실성이 기업에는 많은 부담을 주는 요인이 될 수 있다. 이러한 면에서 R&D 투자가 기업 가치에 양(+)의 영향을 미치기까지의 시간을 측정할 수 있는 연구의 필요성이 있다고 보여진다. 본 연구는 GMM-PVAR(Panel Vector Autoregression) IRF(Impulse Response function)를 사용하여 1900년부터 2015년까지 한국거래소의 코스피와 코스닥시장에 상장된 기업을 대상으로 R&D 투자가 기업가치에 양(+)의 영향을 미치기까지 걸리는 시간을 측정 하였다. 또한 기업의 재무적 특성 변수 중 기업의 크기, 성장 가능성, 그리고 산업 집중율이 R&D 투자가 기업가치에 양(+) 영향을 미치기까지 걸리는 시간을 단축시킨다는 점을 발견하였다. 그것은 이들 재무적 특성변수 들이 R&D 투자와 기업가치간의 관계에 긍정적인 영향을 미칠수록 즉 경쟁이 심화될수록 크기가 클수록 시간이 단축되며 작은 기업의 경우는 성장 가능성이 높을수록 시간이 단축되는 경향을 보였다. 흥미 있는 점은 큰 기업들의 경우에는 성장가능성이 낮은 기업들이 성장가능성이 높은 기업들보다 더 큰 양의 결과를 보였다.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2017년도 9th Asian Crop Science Association conference
• /
• pp.220-220
• /
• 2017

Soybean (Glycine max (L.) Merill) is a very outstanding material crop with high protein and oil contents. We conducted this study to evaluate forage value and usability of soybean varieties as livestock forage. Three soybeans cultivars, OT93-26, Geomjeongsaeol, and Pungwon, were evaluated for forage use in this study, and Kwangpyeongok and Yeongwoo were used as check forage corn and rice, respectively. The whole soybean plants were harvested at the R5 (beginning seed development)- and R6 (full seed)-reproductive stages for analyzing forage usability and quality. Days to harvesting of the R5 stage-OT93-26 was the shortest among the tested crops while that of Yeongwoo was 122 days. The fresh and dry matter yields of all 3 soybeans were greater at R6 stage than at R5. Crude protein of the soybean cultivars harvested had a higher compared to the rice and corn regardless of the harvesting stage. Contents of crude fiber, neutral detergent fiber and acid detergent fiber of Yeongwoo had the lowest whereas Pungwon harvested at R5 were the highest. Among the soybeans, digestible dry matter, dry matter intake, and relative feed value of R6-harvested Geomjeongsaeol and Pungwon were high more compared to those at the R5-harvested, but in case of OT93-26 those at R6 stage were inversely measured rather than those at R5 stage. In conclusion, soybean can be used as s forage with high nutritive value for livestock. Moreover, Geomjeongsaeol can be applied to develop new forage soybean varieties with high nutritive value, and R6 stage is the optimum harvesting stage in yield and quality of the tested soybeans more than R5.

• 소성∙가공
• /
• 제23권5호
• /
• pp.311-316
• /
• 2014

In the current study, the R-value behavior of a two-layer clad steel was investigated using finite element analysis. Hill's 1948 anisotropic yield equation was employed to characterize the anisotropic behavior of the steel with different assumed properties: isotropic (R=1) and anisotropic (R=2). Experimental R-values were determined by measuring the width and thickness ratios of tensile specimens. Finite element analysis results demonstrate a difference in strain behavior in the width and the thickness directions of the clad steel. The R-value behavior depends on the fraction of the clad materials and total elongation.

• 기술혁신학회지
• /
• 제8권1호
• /
• pp.29-50
• /
• 2005

Real options provide a new and productive way to view corporate r&d investment decisions. DCF approach is well established and beloved of financial executives, but is known to systematically underestimate investment value under significant uncertainty. Though real options are not inherent in a r&d investment, they can be used to compute the investment value including managerial flexibility like option value. In this paper, we explain how the interval of option value in black-scholes model can be estimated using simulation. We also present a process framework for interval estimation of volatility and efficient of period of investment value. In such a setting, we can obtain the appropriate interval estimation of the expanded investment value.

• 기술혁신연구
• /
• 제4권1호
• /
• pp.165-183
• /
• 1996

In acquiring and transferring a superior knowledge assesing the intermediate result value of a competitive R&D project is very important for a firm engaging in R&D. Most existing literatures on R&D evaluation are concerned with project selection and resource allocation. In this paper the stage of an R&D project is classified into research, exploratory development, and development. And a model is suggested which evaluates the intermediate result value before completion of development stage under duopoly and oligopolistic competition. Assessed value of the intermediate result transferred to the next tier company can be used as a minimum acceptable price to the inventor when more advanced knowledge acquired through R&D is transferred to the next tier one. The model suggested is composed of structural variables including research cost, success rates, potential profits, discount rate degree of competition. By using exponential distribution for invertion process time in each stage, we derive a formula that can assess the value of the intermediate result, and we demonstrate how the model can be applied to a competitive R&D situation through an example.

• 산업경영시스템학회지
• /
• 제42권2호
• /
• pp.62-68
• /
• 2019

The growth and employment effects of R&D investment were analyzed according to business size, export value and manufacturing sectors so as to suggest improvement directions for effective industry policies. The effect of R&D investment was considered simultaneously from the two perspectives of growth and employment effect, and the causality analysis was carried out by using a path analysis. The result of the path analysis confirmed significant differences in the growth effect of R&D investment depending on business size. However, the effect of increasing employment was difficult to obtain statistically significant results for any various combinations of business size and export value. This is a mixture of directions for the effects of R&D investment on employment, which could be due to the failure to consider appropriate time lags between investment and effect. Efficiency analysis by industry sectors confirmed significant differences in efficiency depending on business size, but differences depending on export value were difficult to identify. In order to derive improvement policy by industry sector according to business size and export value, the direction of selective support policy and universal support policy was derived for six industry groups by combining the return to scale in the efficiency analysis and R&D concentration. Hirschman-Herfindahl index is used for calculating R&D concentration.

• 한국산학기술학회논문지
• /
• 제20권11호
• /
• pp.487-493
• /
• 2019

본 연구는 제약기업대상 연구개발비 무형자산비중을 살펴보고, 무형자산화 비중이 기업 가치에 영향을 미치는지 코스닥제약기업 중심으로 살펴보았다. 연구대상은 2011년부터 2017년까지 코스닥에 상장된 연도별, 기업별 연구개발비 회계자료가 있는 제약기업 39개를 표본으로 종속변수로 토빈Q, 독립변수로 연구개발비 무형자산화 비중으로 설계하여 패널데이터모형으로 분석하였다. 결론은 코스닥제약기업은 연구개발비 무형자산화 비중이 토빈Q(기업가치)에 부정적인 영향을 미치는 것으로 나타났다. 연구개발비 무형자산비중이 클수록 코스닥 제약기업에서는 기업가치가 낮아질 수 있다는 시사점을 제공한다. 즉, 코스닥 제약기업에서는 부채비율이 높을수록 투자규모를 늘리는 현상을 반영하기에 무형자산 비중이 커진다고 해서 기업가치가 증가하지 않는다는 것으로 설명할 수 있다. 본 연구는 기존 연구들은 연구개발비 총액을 기업 가치와 관련성을 규명한 연구들이 대부분인 반면, 연구개발비를 좀 더 세분화해서 '무형자산화 비중'만을 놓고, 코스닥 제약기업의 기업 가치에 영향을 미치는지 여부를 연구했다는 데 그 의의가 있다.