• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1494-1500
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• 2012

Fermentation with filamentous fungi in a bioreactor is a complex dynamic process that is affected by flow conditions and the evolution of the rheological properties of the medium. These properties are mainly affected by the biomass concentration and the morphology of the fungus. In this work, the rheological properties of a fermentation with the fungus Beauveria bassiana under different hydrodynamic conditions were studied and the rheological behavior of this broth was simulated through a mixture of carboxymethyl cellulose sodium and cellulose fibers (CMCNa-SF). The bioreactor was a 10 L CSTR tank operated at different stir velocities. Rheological results were similar at 100 and 300 rpm for both systems. However, there was a significant increase in the viscosity accompanied by a change in the consistence index, calculated according to the power law model, for both systems at 800 rpm. The systems exhibited shear-thinning behavior at all stir velocities, which was determined with the power law model. The mixing time was observed to increase as the cellulose content in the system increased and, consequently, the efficiency of mixing diminished. These results are thought to be due to the rheological and morphological similarities of the two fungal systems. These results will help in the optimization of scale-up production of these fungi.

• 천문학회지
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• 제55권5호
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• pp.173-194
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• 2022

We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016-2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 𝜇as < 𝜃_E < 26 𝜇as, which is consistent with the gap in Einstein timescales near t_E ~ 0.5 days found by Mróz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of free-floating planet candidates (FFPs) dN_FFP/d log M = (0.4 ± 0.2) (M/38 M_⊕)^-p/star, with 0.9 ≲ p ≲ 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index 𝛾 = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of 'Oumuamua-like objects. In particular, if we assume that 'Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 ± 0.06. If the Solar System's endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.

• 전기의세계
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• 제26권2호
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• pp.99-103
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• 1977

The object of this work is to study an optimal design problem of the proportional load-frequency controller for the single-control area power system. The selfservice power station is still a popular means as a power supplying source on ships or in a certain manufacturing area. The power system of this kind can be formulated as a single control-area system and it attracts a certain academic interest in controlling the system frequency under disturbances. In this paper, the single control-area system is mathematically formulated as a linear, time-invariant system in state-space under certain assumptions. The optimal proportional control law and the realization of the controller in closed loop-version is studied so that the final system designed can attain the system frequency to the nominal stationing value after the small load-disturbance. As in general cases of optimal design problems, the performance index is assumed to be quadratic in states and the control effort, and the infinite time control process is assumed in this work. The final control system realized depicts certain improvements in case study; in stability, transient responses and in steady-state frequency deviation, even though the steady state error did not attain the zero value.

• 대한조선학회논문집
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• 제55권6호
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• pp.466-473
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• 2018

Most frequency domain-based approaches assume that structural response should be a Gaussian random process. But a lot of non-Gaussian processes caused by multi-excitation and non-linearity in structural responses or load itself are observed in many real engineering problems. In this study, the effect of non-Normality on fatigue damages are discussed through case study. The accuracy of four frequency domain methods for non-Gaussian processes are compared in the case study. Power-law and Hermite models which are derived for non-Gaussian narrow-banded process tend to estimate fatigue damages less accurate than time domain results in small kurtosis and in case of large kurtosis they give conservative results. Weibull model seems to give conservative results in all environmental conditions considered. Among the four methods, Benascuitti-Tovo model for non-Gaussian process gives the best results in case study. This study could serve as background material for understanding the effect of non-normality on fatigue damages.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1993년도 추계학술발표회 초록집
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• pp.31-36
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• 1993

Three different methods were employed to measure the degree of aerial oxidation in coal and the resulting oxidation/weathering indices were applied to obtain kinetic parameters of aerial oxidation processes, The index (i.e., slurry pH, Free Swelling Index, weight gain) values were subjected to kinetic analysis based on power-law Arrhenius type reaction model. The results show that activation energy of the aerial oxidation in 20-29$0^{\circ}C$ is in the range of 12-16 ㎉/㏖ and the agreement among three techniques is remarkable. The first order kinetic model is suitable in describing low temperature aerial oxidation process, except in the FSI case where the zero order expression is the best one.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.179-180
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• 2015

The task of measuring losses becomes more challenging with ever increasing efficiencies and operating frequencies in power electronics applications. Generally, the process of traditional switching loss calculation in flyback converter is very complicated. MOSFET drain-source voltage and current waveforms are needed to calculate switching loss. However, as we know in switched capacitor converter, switching loss can be easily calculated by charge and energy conservation law with known initial and final capacitor voltages. In this paper, the same method is applied to fly-back converter switching loss analysis to simplify calculation procedure.

• 시큐리티연구
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• 제1호
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• pp.283-319
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• 1997

Our society witnesses the rapid progress in the areas of politics, economy, society and culture in the process of national modernization since 1960s, which in turn as a reverse function gets to contract a societic pathology, totally lowering the security level of citizens' lives owing to various violent crimes like hostage commotions and murders with rifles and deadly weapons. what is the main reason for that? That may be partly because the chief police force concentrates on the current situation resulting in the vacuum of the public peace. However, the main reason is that the police fall short of man-power and equipments even if the whole police power were put to use in preventing and quelling the crimes. That is true not only of Korea but also of the advanced countries like the U.S.A., England and Japan. We realize that these advanced countries have higher level of security in every individual's life and property than Korea because their progress of the private guard systems can fill in a vacuum of the shortage of the police power, Therefore, we should without delay internationalize our private guard systems expecting the widely opening of the guard service markets in the age of Uruguay Round. To do this, we need to change our ideas for fostering the policy of the private guard from passive defense ideas into positive aggressive ones. Our police should urgently set up a plan to pursue the orientation of vision that we should dispatch our private guards overseas before foreign guards rush into our markets. Accordingly it goes without saying that the private guard group should distinguish their services from the public services initiating their own theory and strategy of private guard services and also readjust themselves between the public duties and the private services with the study of minimizing the reverse function of the private guard systems. The history criminal justice has always shown that the criminal system progressed at the initiative of the civil factor in case its demand and supply do not make both ends meet. Nevertheless, in the process the power of the government never weakens, rather it is built up in general. In conclusion, the necessity of the build-up of the private guard services must duly be acknowledged by the police as well as by the business which has its unique sphere within the criminal justice instead of as the suplemtary services of the simple the police power on the long-term basis. The purpose of the private guard services can be largely classified into the two categories; first it means the function to prevent the crimes against the citizens and secondly to enhance the national interest as an increasing mammoth business with a worldly competition capacity. The police has an absolute responsibility that they should protect the modem public in general from feeling the crisis of the personal threat, tension, anxiety and nervousness. In short, if we develop the complete private guard system to guarantee the societic atmosphere for all citizens, keep the public peace, and protect all citizens' lives and properties, we will sure enjoy a beautiful land, a wholesome society and a happy life in goodharmony of law and order.

• 항공우주정책ㆍ법학회지
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• 제1권
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• pp.223-243
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• 1989

The practical application of modern space science and technology have resulted in many actual and potential gains of mankind. These successes have conditioned and increased the need for a viable space law regime and the challenge of space has ultimately led to the formation of an international legal regime for space. Space law is no longer a primitive law. It is a modern law. Yet, in its stages of growth, it has not reached the condition of perfection. Therefore, under the existing state of thing, we could carefully say that the space law is one of the most newest fields of jurisprudence despite the fact that no one has so far defined it perfectly. However, if space law can be a true jurisprudential entity, it must be definable. In defining the space law, first of all, the grasp of it's nature iis inevitable. Although space law encompasses many tenets and facets of other legal discriplines, its principal nature is public international law, because space law affects and effects law relating intercourse among nations. Since early 1960s when mankind was first able to flight and stay in outer space, the necessity to control and administrate the space activities of human beings has growingly increased. The leading law-formulating agency to this purpose is the United Nation's ad hoc Committee on Peaceful Uses of Outer Space("COPUOS"). COPUOS gave direction to public international space law by establishing the 1963 Declaration of Legal Principles Governing the Activities of the States in the Exploration and Use of Outer Space("1963 Declaration"). The 1963 Declaration is very foundation of the five international multilateral treaties that were established successively after the 1963 Declaration. The five treaties are as follows: 1) The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space including Moon and other Celestial Bodies, 1967. 2) The Agreement on the Rescue of Astronauts, the Return of Astronauts, and the Return of Objects Launched into Outer Space, 1968. 3) The Convention on International Liability for Damage Caused by Space Objects, 1972. 4) The Convention on Registration of Objects Launched into Outer Space, 1974. 5) The Agreement Governing Activities of States on the Moon and Other Celestial Bodies: Moon Treaty, 1979. The other face of space law is it's commercial aspect. Space is no longer the sole domination of governments. Many private enterprise have already moved directly or indirectly into space activities in the parts such as telecommunications and space manufacturing. Since space law as the public international law has already advanced in accordance with the developments of space science and technology, there left only a few areas untouched in this field of law. Therefore the possibility of rapid growth of space law is expected in the parts of commerical space law, as it is, at this time, in a nascent state. The resources of the space environment are also commercially both valuable and important since the resources include the tangible natural resources to be found on the moon and other celestial bodies. Other space-based resources are solar energy, geostationary and geosynchronous orbital positions, radio frequencies, area possibly suited to human habitations, all areas and materials lending themselves to scientific research and inquiry. Remote sensing, space manufacturing and space transportation services are also another potential areas in which commercial. endeavors of Mankind can be carried out. In this regard, space insurance is also one of the most important devices allowing mankind to proceed with commercial space venture. Thus, knowlege of how space insurance came into existence and what it covers is necessary to understand the legal issues peculiar to space law. As a conclusion the writer emphasized the international cooperation of all nations in space activities of mankind, because space commerce, by its nature, will give rise many legal issues of international scope and concern. Important national and world-community interests would be served over time through the acceptance of new international agreements relating to remote sencing, direct television broadcasting, the use of nuclear power sources in space, the regularization of the activities of space transportation systems. standards respecting contamination and pollution, and a practical boundary between outer space and air space. If space activity regulation does not move beyond the national level, the peaceful exploration of space for all mankind will not be realized. For the efficient regulation on private and governmental space activities, the creation of an international space agency, similar to the International Civil Aviation Organization but modified to meet the needs of space technology, will be required. But prior to creation of an international organization, it will be necessary to establish, at national level, the Office of Air and Space Bureau, which will administrate liscence liscence application process, safety review and sale of launch equipment, and will carry out launch service.

• 한국생활과학회지
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• 제18권3호
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• pp.793-798
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• 2009

Hair cut is one of the best useful technical tool for hair styling. In this study using the rule of the layers of hair design, balanced for visual art, perceptual ability and form created by the principles of analysis and offer hair cuts and hair design of the representation of regions and even hair design as the basis of a student of Hair Beauty and all the people working in the field can create a variety of hair design puts the purpose to establish a basis. The result of this study can be outline as follows: First, the step line and the movement of the relationship between the law of the layers above and below the length of the same layer techniques, the same consists of a vertical cross-section of the overall round shape of the cut same layer is created and the appropriate volume and movement, the movement of low-layer round a little bit more feeling and expression is used when you want. High-layer used to want to move a lot of light and could see that. Second, the layer of the Law and over direction, lifting, section, the line control. weight control and analyzed by principle and the principle of the process of forming the written form was unknown. Third, hair design, the expansion of the expressive power of the law of the layers, and the section of the over direction depends on the presence of line control to express the length of the outline I had to, lifting the weight to adjust form controls, and the expression of Hair Design will be expanding the width. A hair designer, a layer style to create a zone he thought the law of the first layer formative area To further the reach will be a lot of research, leading up formative aspects of this research thesis do not have missing parts, or as a result of the Beauty of Hair Design and the width of a hair design education in the field can perform to help feed the reference materials that will be.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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• pp.51-54
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• 2000

This paper presents an efficient method for estimating maximum simultaneous switching noise(SSN) of ground interconnection networks in CMOS systems. For the derivation of maximum SSN expression we use ａ-power law MOS model and an iterative method to reduce error that may occur due to the assumptions used in the derivation process. The accuracy of the proposed method is verified by comparing the results with those of previous researches and HSPICE simulations under the present process parameters and environmental conditions. Our method predicts the maximum SSN values more accurately as compared to existing approaches even in more practical cases such that there exist some of output drivers not in transition.