• Journal of Microbiology and Biotechnology
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• v.25 no.2
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• pp.185-195
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• 2015

Glucoamylase is an important industrial enzyme. Glucoamylase production by industrial Aspergillus niger strain featured with two major problems: (i) empirical substrate feeding methods deteriorating the fermentation performance; and (ii) the high raw materials cost limiting the economics of the glucoamylase product with delegated specification. In this study, we first proposed a novel three-stage varied-rate substrate feeding strategy for efficient glucoamylase production in a 5 L bioreactor using the standard feeding medium, by comparing the changing patterns of the important physiological parameters such as DO, OUR, RQ, etc., when using different substrate feeding strategies. With this strategy, the glucoamylase activity and productivity reached higher levels of 11,000 U/ml and 84.6 U/ml/h, respectively. The performance enhancement in this case was beneficial from the following results: DO and OUR could be controlled at the higher levels (30%, 43.83 mmol/l/h), while RQ was maintained at a stable/lower level of 0.60 simultaneously throughout the fed-batch phase. Based on this three-stage varied-rate substrate feeding strategy, we further evaluated the economics of using alternative carbon sources, attempting to reduce the raw materials cost. The results revealed that cornstarch hydrolysate could be considered as the best carbon source to replace the standard and expensive feeding medium. In this case, the production cost of the glucoamylase with delegated specification (5,000 U/ml) could be saved by more than 61% while the product quality be ensured simultaneously. The proposed strategy showed application potential in improving the economics of industrial glucoamylase production.

• Korea Trade Review
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• v.44 no.2
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• pp.109-126
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• 2019

Import refusals can be considered a new method of non-tariff barriers. This study aims to analyze reputation spillover effects on fish and fishery products imported from ASEAN countries to the U.S. FDA. The supply of aquatic products is not stable due to various factors such as reduction of fish stocks and climate change. Fish is a basic food ingested directly, but there are many ways to control the safety of aquatic products. ASEAN countries account for about 20% of U.S.imports in fish and fishery products. For Southeast Asian countries, fish and fishery products comprise a high proportion of exports revenue. Despite the large share of exports to the U.S., Southeast Asia countries have been receiving many import refusals from the United States. In this study, a theoretical model for examining import refusals is suggested using the negative binomial counting process. The reputation spillover effect, was divided into two spillover effects of 'neighbor reputation' and 'sector reputation'. Results show that there exists a neighbor reputation spillover effect. It can be said if there was a import refusal of the same product from neighboring countries in the preceding year, the home country have a possibility to experience import refusals of the same product. Therefore, it is interpreted that neighboring countries have good standard compliance can help home countries to effectively reach the target markets. Our findings have a important policy implication for ASEAN exporters of fish and fishery products.

• Korean Journal of Organic Agriculture
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• v.12 no.2
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• pp.135-151
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• 2004

U.S. organic farming has grown rapidly-20 percent or more annually-throughout the 1990s, which kept pace with consumer demand for organically produced food. Thus certified organic acreage is the total to 235 million acres in 48 state in 2001, and SO the U.S. ranked fourth in land area managed under organic farming systems. And according to several surveys, consumer's reasons for purchasing organic food are health and nutrition, taste and environmental concerns. California and North Dakota were the top two states in 2001 for certified organic cropland; the former with mostly fruits and vegetables, and the latter with wheat, soybeans, and other crops. And the top two states for certified organic pasture were Colorado and Texas. And then several states such as Iowa and Minnesota have begun subsidizing conversion to organic farming systems as a way to capture the environmental benefits of these systems. The price of organic produce fluctuates rather broadly because of being traded by market economy principle and of demand-supply disequilibrium. Nevertheless, average price premiums for organic produce are higher than the prices for the produce under conventional farming. Future prospects for U.S. organic farming are as follows; Demand for organically grown foods is expected to continue growing at a rapid pace, as more growers convert to organic production and more processors and distributors expand organic selections in their product lines. And new processed products and new types of healthy foods are likely to appear on the market, and some new organic products will be aimed at mainstream markets.

• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.67-75
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• 1999

The purpose of this study is to evaluate the friction coefficients between abutment materials and clasp materials, and to an estimation formula for retention force. The coefficients of friction between three clasp materials and four abutment materials were measured under various conditions, polished and sandblasted and wet and dry. The measurement was repeated for each combination up to a total measurement of 1200 times. Estimation formula for retention force is measured as sum of two terms, which the one time is proportional to the product of friction coefficient ${\mu}$ and undercut u and the other term is proportional to u-squared. Two proportional coefficient were obtained by least square method. The results are as follows: 1. Friction coefficients were ranged from 0.08 to 0.53 under various conditions. 2. Friction coefficients of non-metal abutment materials are greater in wet conditions than dry conditions. 3. Friction coefficients of sandblasted clasp against abutment are greater than that of polished clasp. 4. Clasp retention force can be estimated with the model as F=$F_d(3.0{\mu}u+1.5u^2/h)$ with minor error.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.1
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• pp.24-31
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• 1995

This study was performed to investigate the color stability and shear bond strength of denture repair resins. The denture base resins used in this study were Premium Super-20(Lang Dental Mfg. Co., Inc.,.U.S.A.) as heat curing resin, Triad VLC Denture Base(Dentsply/York Division, U.S.A.), Triad Reline Material(Dentsply/York Division, U.S.A.), Repair Acrylic(Lang Dental Mfg. Co., Inc.,. U.S.A.), Toughron Rebase (MikiChemical Product, Kyoto, Japan), and Tokuso Rebase(Tokuyama Soda Co., Ltd., Japan) as denture repair resin. After fabrication of specimens, they stored for 20 months, then color changes and shear bond strength were measured by colorimeter(Model TC-6FX, Tokyo Denshoku Co.) and Instron Universial Test Machine. The results were as follows : 1. There were changes of $L^{\ast},\;a^{\ast},\;b^{\ast}$ and $DE^{\ast}$ in Triad VLC Denture Base after 20 months. 2. There were changes of $a^{\ast}$ in Toughron Rebase and Tokuso Rebase, and $b^{\ast}$ in Tokuso Rebase after 20 months. 3. The shear bond strength of Repair Acrylic and Toughron Rebase were higher than that of Tokuso Rebase and Triad Reline Material.

• Journal of the Korean Home Economics Association
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• v.39 no.1
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• pp.11-27
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• 2001

The purposes of this study are to (1) point out Korean women's clothing behaviors as seen by the Korean who has lived in the U.S.A. (2) identify cultural and social factors to influence on Korean women's clothing behaviors (3) suggest directions for desirable change in clothing consumption behaviors of Korean women. Verbatim texts of 16 interviews concerning Korean women's perception and experiences of fashion in Korea and the U.S. are interpreted through the analysis of the interviews. The results are as follows: 1) In Korea, the changes in fashion are not only distinct but also foster then those in America. 2) Korean women have a tendency to conform in the way they dress themselves, while the women in the U.S.A. put emphasis on the individuality rather than the current fashion. 3) When they go shopping, Korean women take a great note of what the brands represent, but their American counterparts take the neatness, easeness of cleaning and practicality into consideration. 4) In Korea, the clothing behaviors are influenced by the rapid social changes, its internalization trend, the traditional Confucianism and the pressure to conform according to the collectivism.

• Journal of the Korean Mathematical Society
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• v.56 no.4
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• pp.869-915
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• 2019

Let H be a Krull monoid with class group G such that every class contains a prime divisor. Then every nonunit $a{\in}H$ can be written as a finite product of irreducible elements. If $a=u_1{\cdot}\;{\ldots}\;{\cdot}u_k$ with irreducibles $u_1,{\ldots},u_k{\in}H$, then k is called the length of the factorization and the set L(a) of all possible k is the set of lengths of a. It is well-known that the system ${\mathcal{L}}(H)=\{{\mathcal{L}}(a){\mid}a{\in}H\}$ depends only on the class group G. We study the inverse question asking whether the system ${\mathcal{L}}(H)$ is characteristic for the class group. Let H' be a further Krull monoid with class group G' such that every class contains a prime divisor and suppose that ${\mathcal{L}}(H)={\mathcal{L}}(H^{\prime})$. We show that, if one of the groups G and G' is finite and has rank at most two, then G and G' are isomorphic (apart from two well-known exceptions).

• Journal of applied mathematics & informatics
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• v.41 no.4
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• pp.839-848
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• 2023

Let G be a simple undirected graph. A planar graph known as a Halin graph(HG) is characterised by having three connected and pendent vertices of a tree that are connected by an outer cycle. A subset S of V is said to be a dominating set of the graph G if each vertex u that is part of V is dominated by at least one element v that is a part of S. The domination number of a graph is denoted by the γ(G), and it corresponds to the minimum size of a dominating set. A dominating set S is called a secure dominating set if for each v ∈ V＼S there exists u ∈ S such that v is adjacent to u and S₁ = (S＼{v}) ∪ {u} is a dominating set. The minimum cardinality of a secure dominating set of G is equal to the secure domination number γ_s(G). In this article we found the secure domination number of Halin graph(HG) with perfet k-ary tree and also we determined secure domination of rooted product of special trees.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.645-650
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• 2017

This technical note demonstrates the feasibility of using laser ablation inductively coupled plasma mass spectrometry for the characterization of U-7Mo/Ale5Si dispersion fuel. Our measurements show 5.0% Relative Standard Deviation (RSD) for the reproducibility of measured $^{98}Mo/^{238}U$ ratios in fuel particles from spot analysis, and 3.4% RSD for $^{98}Mo/^{238}U$ ratios in a NIST-SRM 612 glass standard. Line scanning allows for the distinction of U-7Mo fuel particles from the Al-5Si matrix. Each mass spectrum peak indicates the presence of U-7Mo fuel particles, and the time width of each peak corresponds to the size of that fuel particle. The size of the fuel particles is estimated from the time width of the mass spectrum peak for $^{98}Mo$ by considering the scan rate used during the line scan. This preliminary application clearly demonstrates that laser ablation inductively coupled plasma mass spectrometry can directly identify isotope ratios and sizes of the fuel particles in U-Mo/Al dispersion fuel. Once optimized further, this instrument will be a powerful tool for investigating irradiated dispersion fuels in terms of fission product distributions in fuel matrices, and the changes in fuel particle size or shape after irradiation.

• Journal of Distribution Science
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• v.18 no.3
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• pp.77-85
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• 2020

Purpose: This study examined marketing value as online word-of-mouth media in the foodservice industry, and it did research on online word-of-mouth (e-WOM) communication marketing schemes using mass communication in the industry. The study is also intended to investigate the impact of electronic word-of-mouth (e-WOM) information and communication on product awareness risks, benefits, and word-of-mouth (WOM) impacts on restaurant consumers. Research design, data, and methodology: The analysis was conducted on a valid questionnaire of 425 menu product consumers. The survey was conducted for two months in March 2019. The collected data was analyzed using SPSS and hierarchical regression analysis was applied. Results: It did empirical research on the reciprocal casual relations to online and the existing word-of-mouth communication that have to be preceded to understand characteristics of online word-of-mouth communication for the purpose of this study. The result is summarized as follows. First, the online word-of-mouth (e-WOM) effect on product recognition risk shows the statistically significant effect of information sender characteristics, information recipient characteristics, and online word-of-mouth (e-WOM) communication on product recognition risk. Second, the influence of online word-of-mouth (e-WOM) on product risk benefits shows that the information sender characteristics, the information receiver characteristics, and online communications have a statistically significant effect on product risk benefits. Third, online word of mouth risk recognition had a statistically significant effect on word of mouth acceptance. Fourth, online risk benefit had a statistically significant positive effect on word of mouth (WOM) effect. Conclusions: The communication between online word of mouth (e-WOM) sender and recipient had a positive influence on the product evaluation and attitude change in the foodservice industry, and the word-of-mouth (WOM) effect affected financial and non-financial performance. The results mentioned above indicated that the communication between the sender of the information and the receiver of the information had a positive effect on the product evaluation and attitude change of the menu consumer, and the word-of-mouth (WOM) result affected the financial. Therefore, the online word-of-mouth (e-WOM) effect has a positive effect on the word-of-mouth (WOM) effect of menu products when performed simultaneously and positively between the information sender and the information receiver.