• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1242-1251
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• 2016

The ethanol production of Trichoderma reesei was improved by genome shuffling in our previous work. Using RNA-Seq, the transcriptomes of T. reesei wild-type CICC40360 and recombinant strain HJ48 were compared under fermentation conditions. Based on this analysis, we defined a set of T. reesei genes involved in ethanol production. Further expression analysis identified a series of glycolysis enzymes, which are upregulated in the recombinant strain HJ48 under fermentation conditions. The differentially expressed genes were further validated by qPCR. The present study will be helpful for future studies on ethanol fermentation as well as the roles of the involved genes. This research reveals several major differences in metabolic pathways between recombinant strain HJ48 and wild-type CICC40360, which relates to the higher ethanol production on the former, and their further research could promote the development of techniques for increasing ethanol production.

• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1182-1189
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• 2016

Lactobacillus brevis ATCC 14869 exhibited a carbon catabolite derepressed phenotype that has ability to consume fermentable sugars simultaneously with glucose. To evaluate this unusual phenotype under harsh conditions during fermentation, the effects of lactic acid and hydrogen ion concentrations on L. brevis ATCC 14869 were examined. Kinetic equations describing the relationship between specific cell growth rate and lactic acid or hydrogen ion concentration were deduced empirically. The change of substrate utilization and product formation according to lactic acid and hydrogen ion concentration in the media were quantitatively described. Although the simultaneous utilization has been observed regardless of hydrogen ion or lactic acid concentration, the preference of substrates and the formation of two-carbon products were changed significantly. In particular, acetic acid present in the medium as sodium acetate was consumed by L. brevis ATCC 14869 under extreme pH of both acid and alkaline conditions.

• International Journal of Fluid Machinery and Systems
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• 제7권1호
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• pp.1-6
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• 2014

The propellant acquisition vane (PAV) is a key part of a vane type surface tension propellant management device (PMD), which can manage the propellant effectively. In the present paper, the fluid transportation behaviors for five PAVs with different sections were investigated by using microgravity drop tower test. Further, numerical simulation for the propellant flow in a PMD under microgravity condition was also carried out based on VOF model, and showed the similar flow pattern for PAVs to the experiment. It is noted that the section geometry of PAVs is one of the main factors affecting the fluid transportation behavior of PMD. PAVs with bottom length ratio of 5/6 and 1/2 have larger propellant transportation velocity. Based on the experiments, there were two stages during the process of propellant transportation under microgravity environment: liquid relocation and steady transportation stage. It is also recognized that there is a linear correlation between liquid transportation velocity and relative time's square root. Those results can not only provide a guideline for optimization of new vane type PMDs, but also are helpful for fluid control applications in space environment.

• 아시안잔디학회지
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• 제12권4호
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• pp.211-220
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• 1998

Cellulose-degrading fungi were idenfied as Rhizoctonia solani AG2-2(IV), T. harzianum and C. cochliodes. Rhizoctonia solani AG2-2(IV) grows better in the acidified media of pH 4 and 5 than pH 6 and 7. Mycelial growth of T. harzianum and C. cochliodes was also higher in pH 4 and 5 than in pH 6 and 7. In order to relate the above findings to nutrient utilization, mycelial growth of R. solani AG2-2(IV) are evaluated with various carbon sources. R. solani AG2-2(IV) grows well in the order of mannose, cellobiose, glucose, xylose and arabinose. However, mycelial dry weights of T. harzianum were 98.7, 78.0, 72.3, 43.7 and 32.3mg in glucose, mannose, cellobiose, xylose, and arabinose, respectively. Mycelial dry weight of C. cochilodes was 118, 65, 57, 49, and 16mg in mannose, cellobiose, xylose, glucose, and arabinose, respectively. Result of cellulase assay of R. solani AG2-2(IV) and soil fungi was reffered as, R. solani AG2-2(IV) produced more cellulase on CMC substrate than on CEL and secretes more enzyme in floated condition than in water-immersed condition. T. harzianum secreted less amount of cellulase than R. solani AG2-2 and C. cochliodes. T. harzianum produced no enzyme on CEL under water-immersed condition. C. cochliodes produced similar amounts of cellulase on either CMC or CEL under both water-immersed and floated condition.

• 한국태양에너지학회 논문집
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• 제37권2호
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• pp.59-66
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• 2017

This paper compares the output power of different types of small Stirling engines in conjunction with the utilization of low grade thermal energy. A series of experimental measurements were performed to assess the output power of each engine under different conditions of the temperature difference between the hot and cold ends as well as applied weight. Results are presented in terms of torque and output power per heat transfer area. Among tested, the MM-7 engine produced the highest power of 4.455mW ($321mW/m^2$) under a temperature difference of $40^{\circ}C$.

• 한국정보과학회논문지:소프트웨어및응용
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• 제34권5호
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• pp.487-501
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• 2007

고성능 다중 이슈 DSP의 하드웨어 리소스 사용률을 높이기 위해서, 제공되는 상용 컴파일러는 일반적으로 반복 모듈로 스케쥴링(Iterative Modulo Scheduling)을 포함하고 있다. 하지만, 통신 및 미디어 처리 응용의 루프에 존재하는 과도한 순환 데이타 의존관계는 모듈로 스케쥴링 자유도를 제한하고 있다. 결과적으로, 멀티 이슈를 위한 DSP의 병렬 기능 유닛들은 완전히 사용되고 있지 못하다. 이러한 하드웨어 리소스 저사용 문제를 해결하기 위하여, 이 논문은 효율적인 모듈로 스케쥴링을 위한 새로운 컴파일러 전처리 기법을 기술하고 있다. 제안하는 전처리 기법은 두 가지로서 클로닝과 디스맨틀링으로 불리우며, 이 두가지 기법들은 StarCore SC140 DSP 컴파일러에 구현하여 검증하였다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.171-171
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• 1998

The metabolic behavior of Debaryomyces hansenii was investigated in terms of substrate utilization and by product formation under different cultural conditions. Debaryomyces hansenii exhibited best growth and most tolerant of increased NaCl, sucrose and potassium sorbate at their optimum pH (5.0). A combination of two or more environmental stresses had stronger inhibitory effects on their growth kinetics, utilization of carbohydrate substrates and the production of organic acids, volatile compounds and other metabolites. Significant amounts of glycerol (0.35-4.4 g/L) and arabitol (0.08-9.8 g/L) were produced by D. hansenii. The main organic acids produced were citric (0.6-1.4 g/L), acetic (0.3-2.8 g/L), fumaric (0.2-1.0 g/L) and malic acids (1.1-1.7 g/L). A range of other compounds such as ethyl acetate, n-propanol, isoamyl alcohol, 2-phenylethanol and acetoin were also produced. The concentration of these compounds varied with the cultural conditions. Such compounds would have specific impacts on food quality in which D. hansenii is found.

• Journal of Communications and Networks
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• 제16권2호
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• pp.130-139
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• 2014

Due to the unpredictable nature of channel availability, carrying delay-sensitive traffic in cognitive radio networks (CRNs) is very challenging. Spectrum leasing of radio resources has been proposed in the so called coordinated CRNs to improve the quality of service (QoS) experienced by secondary users (SUs). In this paper, the performance of coordinated CRNs under fixed-rate with hard-delay-constraints traffic is analyzed. For the adequate and fair performance comparison, call admission control strategies with fractional channel reservation to prioritize ongoing secondary calls over new ones are considered. Maximum Erlang capacity is obtained by optimizing the number of reserved channels. Numerical results reveal that system performance strongly depends on the value of the mean secondary service time relative to the mean primary service time. Additionally, numerical results show that, in CRNs without spectrum leasing, there exists a critical utilization factor of the primary resources from which it is not longer possible to guarantee the required QoS of SUs and, therefore, services with hard delay constraints cannot be even supported in CRNs. Thus, spectrum leasing can be essential for CRN operators to provide the QoS demanded by fixed-rate applications with hard delay constraints. Finally, the cost per capacity Erlang as function of both the utilization factor of the primary resources and the maximum allowed number of simultaneously rented channels is evaluated.

• 반도체디스플레이기술학회지
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• 제7권1호
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• pp.29-34
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• 2008

In this paper, the DE(double erosion) cathode for the reactive magnetron sputtering system is developed for high deposition rate and high target utilization efficiency. The utilization efficiency of the developed DE cathode is 22% higher than that of normal SE(single erosion) cathode. Sputtering process for the nickel oxide thin films with the DE cathode is performed under the following conditions; power with $1kW{\sim}3kW$, pressure with 4mtorr and 8mtorr, oxygen flow ratio with $0%{\sim}80%$. As a result, the hysteresis phenomenon of discharge voltage in 4mtorr is lower than that in 8mtorr and the hysteresis phenomenon of discharge voltage is getting lower as the applied power is getting higher. The structure of cross section and surface roughness of the thin films are observed by FE-SEM and AFM. The structure of cross section of the thin films is columnar and the average surface roughness under oxygen flow ratio of 0%, 52.5% and 65.0% are $2.08{\AA}$, $2.20{\AA}$ and $0.854{\AA}$, respectively.

• 신재생에너지
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• 제19권1호
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• pp.41-52
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• 2023

Various carbon upcycling technologies have been proposed and are under development to achieve Korea's carbon neutrality target. Many chemical reactions are under development through various chemical reaction pathways, and different technological maturity levels are shown for each country and company. In this situation, it is essential to establish investment decisions such as research funds and human resources allocation through technological and economic analysis for close commercialization technologies and basic technologies with low technology readiness levels (TRL). Therefore, in this study, the technology development priority for developing carbon upcycling items was selected according to the domestic Carbon Capture & Utilization (CCU) technology roadmap using the stakeholder selection tool released by EU CarbonNext. As a result of the analysis, the TRL level of Korea's major carbon upcycling technologies was analyzed to be lower than that of other carbon resource technologies, and it was considered desirable to invest in mineral carbonization technologies among various candidate technologies.