• Journal of Mechanical Science and Technology
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• 제16권11호
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• pp.1435-1439
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• 2002

This paper presents a form of the cohesive surface separation potential, which can produce potential curves by varying a single dimensionless parameter. Results show that a partial modification of Xu and Needleman's (1994) cohesive surface separation potential makes it possible to present the other potential corves as a special case as long as the normal separation is concerned. The proposed potential may describe interfacial debonding-crack initiation and growth-character of materials and, through numerical simulation, provide an insight for the effect of different cohesive surface separation potentials on the interfacial debonding.

• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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• pp.1794-1802
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• 2001

Biotechnology will play critical role in improving animal productivity. Animal growth rate and muscle deposition potential can be greatly improved by the application of biotechnology and biotechnological products. Administration of recombinant somatotropin (ST) or other compounds such as IGF-1 and growth hormone-releasing peptides (GHRPs) can enhance growth rate and carcass lean percentage. Gene transfer offers a powerful approach to manipulate endocrine system and metabolic pathways toward faster growth and better feed efficiency. Biotechnology is also extensively used for improving metabolism and activity of gut microorganisms for better nutrient digestibility. Knockout of growth-inhibiting genes such as myostatin results in considerable acceleration of body weight and muscle growth. Animal growth can also be improved by the use of gene therapy. Immunomodulation is another approach for efficient growth through controlling the activity of endogenous anabolic hormones. All the above aspects will be discussed in this review.

• 한국결정성장학회지
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• 제9권2호
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• pp.224-230
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• 1999

콜로이드성 알루미나 분말 입자들의 현탁액에서 입자들의 응집현상을 시뮬레이션 하였다. 현탁액 속의 알루미나 분말 입자들은 입자간 포텐셜 에너지를 가지고 있으며 시간이 경과함에 따라 현탁액으 전체적인 에너지를 감소시키는 방향으로 시스템을 변화시킨다. 현탁액 속의 분말 입자들의 응집 현상을 입자간 포텐셜 곡선의 유형에 따라 관찰하였다. 단거리에서 강한 친화 포텐셜 에너지를 가지는 입자들은 무정형 망목 응집구조를 유도하며 응집체의 크기가 작아지고 단거리에서 강한 척력 포텐셜 에너지와 장거리에서 상대적으로 강한 친화 포텐셜 에너지를 가지는 분말 입자들이 밀집충진 응집구조에 접근하고 응집체의 크기가 상대적으로 커지게 된다. 입자간 에너지 분포에 강한 반발에너지 장벽이 존재하는 경우에 입자들이 응집함에 따라 이러한 에너지는 장벽이 사라지게 되며 이러한 현상은 입자의 응집패턴의 변화를 의미한다.

• 대한화학회지
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• 제18권6호
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• pp.391-399
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• 1974

금속 코발트의 부식과 부동화현상들을 전기화학적 실험방법들을 써서 연구하였다. Tafel slope, Flade potential의 pH의존도, 부식속도의 반응역학적 데이타등으로 부터 코발트와 붕산염완충용액 사이 계면에서 일어나는 부식과 부동화 과정들의 메카니즘을 도출하였다. 금속표면에 흡착된 히드록실기가 표면산화와 부동화막의 형성에 참여하는 것으로 나타났다. 표면막의 성장속도에 관한 데이타로 보아 부동화피막은 "전기장에 의한-이온-이동" 과정에 의하여 성장하는 것으로 보인다. 측정된 표면막의 두께는 약 10${\AA}$에서 20${\AA}$에 이르렀다.

• 한국결정성장학회지
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• 제20권1호
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• pp.35-42
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• 2010

In this paper, three types of CNT/$TiO_2$ composite electrodes were prepared with different methods. The changes in XRD patterns showed that the Electrode A contained a mixed phase of anatase and rutile while the Electrode B and Electrode C contained a typical single and clear anatase crystal structure. From SEM micrographs, $TiO_2$ particles were adhered on the surface of the CNT network in the forms of small clusters. The results of chemical elemental analysis indicated that the main elements such as C, O and Ti were existed. The results demonstrated that the efficiency of photoelectrocatalytic (PEC) oxidation for methylene blue (MB) was higher than that of photocatalytic (PC) oxidation. There was a clear enhancement trend of the MB degradation using the prepared CNT/$TiO_2$ composite electrodes with an increase of applied potential. Finally, the prominent PEC activities of the CNT/$TiO_2$ composites could be attributed to combination effects of photo-degradation of $TiO_2$, electron assistant of CNT and function of applied potential.

• 품질경영학회지
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• 제51권4호
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• pp.691-700
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• 2023

Purpose: This study aims to analyze the diffusion pattern of the Mongolian mobile phone market. In particular, we used a generalized diffusion model to explore the factors affecting market potenial. Methods: We used three diffusion models to estimate the number of mobile subscribers in Mongolia. Based on the Logistic model with the best fitness, we introduced time-varying market potential and explored the influence of various independent variables such as GDP and inflation. Results: Among the basic diffusion models, the Logistic model was the best in terms of estimation performance and statistical significance. The estimation results of the Generalized Logistic model confirm that investment in the telecommunication sector has a significant positive effect on market potential. The estimation of the Generalized Logistic model effectively describes the continuous growth of the Mongolian telecommunications market until recently. Conclusion: We have analyzed the diffusion pattern of the Mongolian telecommunications market and found that the amount of investment in the sector leads to the growth of the market size. This study is original in terms of its subject - Mongolian telecommunications market and methodology - time-varying market potential.

• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1290-1302
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• 2016

Microalgae are being researched for their potential as attractive biofuel feedstock, particularly for their lipid production. For maximizing biofuel production, it is necessary to explore the effects of environmental factors on algal lipid-producing potential. In this study, the effects of nitrogen (N) sources (NO₂-N, NO₃-N, urea-N, NH₄-N, and N-deficiency) and carbon-to-nitrogen ratios (C/N= 0, 1.0, 3.0, and 5.0) on algal lipid-producing potential of Chlorella sp. HQ were investigated. The results showed that for Chlorella growth and lipid accumulation potential, NO₂-N was the best amongst the nitrogen sources, and NO₃-N and urea-N also contributed to algal growth and lipid accumulation potential, but NH₄-N and N-deficiency instead caused inhibitory effects. Moreover, the results indicated that algal lipid-producing potential was related to C/N ratios. With NO₂-N treatment and carbon addition (C/N = 1.0, 3.0, and 5.0), total lipid yield was enhanced by 12.96-20.37%, but triacylglycerol (TAG) yields decreased by 25.52-94.31%. As for NO₃-N treatment, carbon addition led to a 17.82-57.43%/25.86-82.67% reduction of total lipid/TAG yields. When NH₄-N was used as the nitrogen source, total lipid/TAG yields were increased by 46.67-113.33%/28.99-74.76% with carbon addition. The total lipid/TAG yields of urea-N treatment varied with C/N ratios. Overall, the highest TAG yield (TAG yield: 38.75 ± 5.21 mg/l; TAG content: 44.16 ± 4.35%) was achieved under NO₂-N treatment without carbon addition (C/N = 0), the condition that had merit for biofuel production.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1998년도 춘계 학술대회지
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• pp.101-102
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• 1998

• 한국환경보건학회지
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• 제23권1호
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• pp.18-27
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• 1997

The isolation, morphological study and growth characteristics of the algae were investigated from Lake Chuam. The isolated algae were applied the Agal Growth Potential test. The method of isolation and purification of the algae were used to Agar plating(AP), nutrient enrichment(NE), dilution(DI) and micro capillary technique(MC). Total isolated algae were 21 species. They were composed of Cyanophyceae, Dinophyceae, Bacillariophyceae, Euglenophyceae and Chlorophyceae. The numbers of algal strain by isolation technique were highest in dilution(21 species), and those of the rests were showed in order of NE > MC > AP. The sizes of isolated Selenastrum and Scenedesmus were $1.8\pm 1.4 \mu m$, $3.3\pm 0.9 \mu m$ in diameter and $6.4\pm 2.3 \mu m$, $13.6\pm 1.9 \mu m$ in length respectively. The morphology of isolated algae and NIES-collection strain was very similar each other, but the size was smaller isolated algae than that of NIES-collection. The optimum culture condition of isolated Selenastrum and Scenedesmus was about 30$\circ$C(25$\circ$C-35$\circ$C) in temperature and the maximum growth was appeared between 7,000 lux and 8,000 lux in the light intensity. The comparison of $\mu$(specific growth rate) on the concentration of nutrients such as nitrate and phosphate, isolated Selenastrum was appeared maximum it at 1.0 mg $NO_3-N/l$ but NIES-collection strain was showed 95% of maximum it at same nitrate concentration. Maximum g of isolated algae and NIES-collection strain in Scenedesmus onto nitrate concentration were very similar with the result of selenastrum. The specific growth rates of isolated algae and NIES-collection strain on the gradient concentration of phosphate were showed 0.72/day and 0.70/day at 0.02 mg $PO_4-P/l$ in Selenastrum but those of Scenedesmus were appeared 0.61/day and 0.57/day at same concentration $PO_4-P$.

• Journal of Korea Trade
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• 제27권2호
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• pp.61-76
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• 2023

Purpose - The digital service trade has become an important driver of the global service trade. The main purpose of this study is to explore the influencing factors of digital service exports from China and Korea to RCEP sample countries respectively, and to comprehensively study the export potential of China and Korea to RCEP countries, so as to provide theoretical guidance and a decision-making reference to promote digital service trade exports and digital economy development in China and Korea. Design/methodology - First, the stochastic frontier gravity model was improved by introducing nonefficiency factors affecting digital services trade, extending the gravity model of traditional services trade exports to digital services trade exports. Secondly, the panel data of China and Korea for the eight sample countries of RCEP from 2011 to 2021 were adopted for the empirical analysis of digital service export potential by a stochastic frontier model. Findings - China's economic growth plays a role in increasing China's digital service trade exports, while Korea's economic growth does not play a significant role in increasing Korea's digital service trade exports. However, the economic growth of trading partner countries can play a significant role in boosting the digital service trade in both China and Korea, and comparison shows that Korea has higher resilience in the digital services trade than China. In addition, the market size of target countries plays a positive role in promoting the digital service trade exports of both China and Korea, and the increase in the value-added share of services in target countries will lead to a decrease in the digital service trade exports of both China and Korea. Originality/value - This study is innovative in terms of research perspective and method. Academic research on the export potential of international trade has been extensive, but most studies are based on the perspective of the goods trade, fewer studies are based on the perspective of the service trade, and there are almost no studies based on the perspective of digital service trade. There is a gap based on the comparative analysis of the export potential of the digital service trade between China and Korea. This study extends the gravitational model of traditional service trade exports to digital service trade exports to comparatively analyze the export potential of China and Korea to RCEP countries. This study addresses this limitation by analyzing a comparative analysis of the digital service trade export potential of China and Korea.