• Title/Summary/Keyword: Potential Functions

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The Structures and Thermal Properties of Divalent Ion Exchanged Zeolite A (2가 이온 치환 제올라이트 A 의 구조와 열적 성질)

  • Jong Yul Park;Yang Kim;Un Sik Kim;Sang Gu Choi
    • Journal of the Korean Chemical Society
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    • v.33 no.4
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    • pp.357-365
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    • 1989
  • The positional parameters of framework atoms, cations, and water molecules in hydrated and dehydrated $Mg_4Na_4-A$, $Ca_6-A$, $Zn_5Na_2-A$ and $Co_4Na_4-A$ were determined by the optimization technique using some potential energy functions and VAIOA optimization program. Upon dehydration, cations in hydrated states move toward the framework oxygens of 6 rings. Frameworks of fully dehydrated zeolite A are more stable than those of fully dehydrated divalent cation exchanged Zeolite A. There are three different kinds of water molecules in divalent cation exchanged Zeolite A; W(III) (water molecules having hydrogen bonds), W(II) (water molecules associated with $Na^+$ ions), and W(I) (water molecules associated with divalent cations). Three different DTA endothermic peaks were observed corresponding to the dehydration of three different kinds of water molecules in divalent cation exchanged Zeolite A.

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A Study on the Marine Environmental Protection of Northeast Asian Seas in International Law (국제법상 동북아해저환경보존에 관한 연구)

  • 이윤철
    • Journal of the Korean Institute of Navigation
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    • v.19 no.2
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    • pp.77-97
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    • 1995
  • The protection of the marine environment is one of the main international legal problems in recent years. In parallel with the industrial development, a great quantity of chemical materials were used and in consequence, mass transportation of oil and other dangerous materials was required on the one hand, and discharge of industrial wasters drew also the attention on the other hand. Furthermore, oil tankers accidents, mass use of nuclear materials, sea-bed exploration and exploitation stimulated further deep human concern on the marine environment. The expansion of international concern to new and more dangerous sources of marine pollution regarded more strict and legal control on the Oil Tanker(DWT 95, 000tons, Cb=0.805) model. Calculation results are compared to the international, especially regional level. In particular, this study is concerned with the preservation of the Northeast Asian Seas surrounded by Japan, the Russian Far East, South Korea, North Korea, China and Taiwan. These adjacent countries must intensify cooperation regarding the prevention, reduction and control of the contamination of the sea. And this cooperation between the States concerned should, as much as possible, be aimed at maximizing the effectiveness of measures to prevent or abate transboundary environmental pollution. To achieve this purpose, States concerned should be imposed upon duties such as duty to assess the environmental impact, duty to inform, duty to consult and duty to assist on the basis of general principle of international law, international customary law and other various resolutions of international bodies. Depending on the nature and extent of actual or potential transboundary pollution with the use of a natural resource or the environment in general the establishment of some form of institutionalized cooperation between the States concerned may become useful or indispensable. The functions of this Organization are, inter alia, to keep the implementation of the Convention and the protocals under continuous observation, to make recommendations on regional or sub-regional rules and standards to be elaborated and on measures to be taken by the Contracting Parties, to be notified of any grave and imminent danger from pollution or threat of pollution by the Contracting Parties and to promote in close cooperation with appropriate governmental bodies additional measures to protect the marine environment of the Northeast Asian Seas, and so on. Above mentioned countries, first of all, are located within the Northeast Asian Seas geographically and, therefore, take responsibilities of preserving the clean sea against marine interferences regardless of any difference of the social, political and economic systems. They must be followed under the UNCLOS and other marine conventions. Under the present circumstances, Northeast Asian Seas will become dead seas in case that there is no instant and prompt action against pollution. Hence we have an absolute obligation to promote the development of the mandatory international environmental law, which in turn can faciliate more effective implementation of the regional cooperation by the neighbouring states within this area.

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A Study on the Verification of Significance of Assessment Items for Selecting Start-ups: Focusing on Project Fostering Start-ups through Leading Universities (창업기업 선정평가지표 유의성 검증에 관한 연구: 창업선도대학육성사업을 중심으로)

  • Jung, Kyung Hee;Sung, Chang So
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.13 no.4
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    • pp.13-22
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    • 2018
  • In this study, we examined the accuracy of the assessment items for selecting start-ups used in the project to support start-ups and verified their validity in determining whether they are appropriate assessment items based on selection criteria. The results of 973 start-ups that applied for the project fostering startup leading universities were collected and logistic regression was performed using SPSS 18.0. The study results are summarized as follows. First, the differences in characteristics of start-ups were identified in terms of selection. Second, the impact of selection by assessment items was gender in 2015, capability of the founder, business establishment in 2016, performance and potential in the global market, and business startup in 2017. Third, the overall selection accuracy analysis for the last three years confirmed that the accuracy of the selection is lower each year and that the accuracy of the selection is lower than the accuracy of the non-selection. This means that the current assessment items for selecting start-ups are inaccurate for selection, and that changes in the items due to changes in the start-up environment each year have led to lower accuracy of selection. It is meaningful that this study raised the importance of assessment items and the need for improvement of assessment items for the screening functions of good start-ups to enhance efficiency of the policies for startup support.

Sensing the Stress: the Role of the Stress-activated p38/Hog1 MAPK Signalling Pathway in Human Pathogenic Fungus Cryptococcus neoformans

  • Bahn, Yong-Sun;Heitman, Joseph
    • Proceedings of the Microbiological Society of Korea Conference
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    • 2007.05a
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    • pp.120-122
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    • 2007
  • All living organisms use numerous signal-transduction pathways to sense and respond to their environments and thereby survive and proliferate in a range of biological niches. Molecular dissection of these signalling networks has increased our understanding of these communication processes and provides a platform for therapeutic intervention when these pathways malfunction in disease states, including infection. Owing to the expanding availability of sequenced genomes, a wealth of genetic and molecular tools and the conservation of signalling networks, members of the fungal kingdom serve as excellent model systems for more complex, multicellular organisms. Here, we employed Cryptococcus neoformans as a model system to understand how fungal-signalling circuits operate at the molecular level to sense and respond to a plethora of environmental stresses, including osmoticshock, UV, high temperature, oxidative stress and toxic drugs/metabolites. The stress-activated p38/Hog1 MAPK pathway is structurally conserved in many organisms as diverse as yeast and mammals, but its regulation is uniquely specialized in a majority of clinical Cryptococcus neoformans serotype A and D strains to control differentiation and virulence factor regulation. C. neoformans Hog1 MAPK is controlled by Pbs2 MAPK kinase (MAPKK). The Pbs2-Hog1 MAPK cascade is controlled by the fungal "two-component" system that is composed of a response regulator, Ssk1, and multiple sensor kinases, including two-component.like (Tco) 1 and Tco2. Tco1 and Tco2 play shared and distinct roles in stress responses and drug sensitivity through the Hog1 MAPK system. Furthermore, each sensor kinase mediates unique cellular functions for virulence and morphological differentiation. We also identified and characterized the Ssk2 MAPKKK upstream of the MAPKK Pbs2 and the MAPK Hog1 in C. neoformans. The SSK2 gene was identified as a potential component responsible for differential Hog1 regulation between the serotype D sibling f1 strains B3501 and B3502 through comparative analysis of their meiotic map with the meiotic segregation of Hog1-dependent sensitivity to the fungicide fludioxonil. Ssk2 is the only polymorphic component in the Hog1 MAPK module, including two coding sequence changes between the SSK2 alleles in B3501 and B3502 strains. To further support this finding, the SSK2 allele exchange completely swapped Hog1-related phenotypes between B3501 and B3502 strains. In the serotype A strain H99, disruption of the SSK2 gene dramatically enhanced capsule biosynthesis and mating efficiency, similar to pbs2 and hog1 mutations. Furthermore, ssk2, pbs2, and hog1 mutants are all hypersensitive to a variety of stresses and completely resistant to fludioxonil. Taken together, these findings indicate that Ssk2 is the critical interface protein connecting the two-component system and the Pbs2-Hog1 pathway in C. neoformans.

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Design of Network Attack Detection and Response Scheme based on Artificial Immune System in WDM Networks (WDM 망에서 인공면역체계 기반의 네트워크 공격 탐지 제어 모델 및 대응 기법 설계)

  • Yoo, Kyung-Min;Yang, Won-Hyuk;Kim, Young-Chon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.4B
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    • pp.566-575
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    • 2010
  • In recent, artificial immune system has become an important research direction in the anomaly detection of networks. The conventional artificial immune systems are usually based on the negative selection that is one of the computational models of self/nonself discrimination. A main problem with self and non-self discrimination is the determination of the frontier between self and non-self. It causes false positive and false negative which are wrong detections. Therefore, additional functions are needed in order to detect potential anomaly while identifying abnormal behavior from analogous symptoms. In this paper, we design novel network attack detection and response schemes based on artificial immune system, and evaluate the performance of the proposed schemes. We firstly generate detector set and design detection and response modules through adopting the interaction between dendritic cells and T-cells. With the sequence of buffer occupancy, a set of detectors is generated by negative selection. The detection module detects the network anomaly with a set of detectors and generates alarm signal to the response module. In order to reduce wrong detections, we also utilize the fuzzy number theory that infers the degree of threat. The degree of threat is calculated by monitoring the number of alarm signals and the intensity of alarm occurrence. The response module sends the control signal to attackers to limit the attack traffic.

Development of the GIS-based Stream Hydromorphological Structure Assessment System for Small and Midium-size Streams (GIS 기반 중·소규모 하천의 수문지형 물리적 구조 평가 체계 개발)

  • Kim, Man-Kyu;Kim, Hye-Ju;Park, Jong-Chul
    • Journal of the Korean Association of Geographic Information Studies
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    • v.11 no.2
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    • pp.93-107
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    • 2008
  • Recently, there have been many projects regarding restoration of streams to recover their environmental and ecological functions. For the restoration of streams, it is valuable academically and economically to evaluate the ecological condition of streams and build a plan and an object for restoring streams based on that. On the other hand, one of the methods to figure out the ecological condition of streams is to evaluate the hydromorphological structure of stream. In this study we have developed a field survey system using the stream assessment methode of LAWA (Laenderarbeitsgemeinschaft Wasser in Germany) that can assess the hydromorphological structure of small and medium streams. In addition, we constructed a GIS-based stream assesment system which can support auto mapping system and report writing, using the survey results. These systems are aimed to help people in the area of restoring streams perceive the natural and ecological condition of streams in the process of making plans and managing the projects, and they also try to help in collecting raw data to determine an ideal potential model to which an existing stream should be turned.

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A Study on the Hydrated and Dehydrated $Mn^{2+}$-Exchanged Zeolite A ($Mn^{2+}$-치환 제올라이트 A 의 수화 및 탈수 구조에 관한 연구)

  • Jong Yul Park;Yang Kim;Un Sik Kim;Sang Gu Choi
    • Journal of the Korean Chemical Society
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    • v.33 no.6
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    • pp.623-632
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    • 1989
  • The positions and interaction energies of framework atoms and water molecules of $Mn^{2+}$-exchanged zeolite A were calculated using some potential energy functions and an optimization program. The sum of interaction energies of framework atoms in dehydrated $Mn_{4,5}Na_3-A$ was approximately the same as those of thermally stable $Ca^{2+}$-or $Mg^{2+}$-exchanged zeolite A. Since $Mn^{2+}$ ions can form good coordination bonds with framework oxygens even in dehydrated state, $Mn^{2+}$-exchanged zeolite A is considered to be thermally stable. The optimized positions of framework atoms and ions in this work are agreed well with the crystallographic data. Three groups of water molecules are found in hydrated $Mn^{2+}$-exchanged zeolite A; W(I) group of water molecules having only hydrogen bonds, W(II) group coordinated to $Na^+$ ion, and W(III) group coordinated to $Mn^{2+}$ ion. The average binding energy of each group of water molecules decrease in the order of W(III) > W(II) > W(I). The activation energies in the dehydration reaction of each group of water molecules increased in accordance with their binding energy.

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Transcript Profiling of Toll-Like Receptor mRNAs in Selected Tissues of Mink (Neovison vison)

  • Tong, Mingwei;Yi, Li;Cheng, Yuening;Zhang, Miao;Cao, Zhigang;Wang, Jianke;Zhao, Hang;Lin, Peng;Yang, Yong;Cheng, Shipeng
    • Journal of Microbiology and Biotechnology
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    • v.26 no.12
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    • pp.2214-2223
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    • 2016
  • Toll-like receptors (TLRs) can recognize conserved molecular patterns and initiate a wide range of innate and adaptive immune responses against invading infectious agents. The aim of this study was to assess the transcript profile of mink TLRs (mTLRs) in mink peripheral blood mononuclear cells (PBMCs) and a range of tissues, and to explore the potential role of mTLRs in the antiviral immune response process. The results indicated that the mTLR partial nucleotide sequences had a high degree of nucleotide identity with ferret sequences (95-98%). Phylogenetic analysis showed that mammalian TLRs grouped into five TLR families, with a closer relationship of the mTLRs with those of ferret than the other mammalian sequences. Moreover, all the mTLRs were ubiquitously expressed in lymphoid organs (spleen and lymph nodes) and PBMCs. Interestingly, the mTLR expression patterns in lung, uterus, and heart showed quite a lot of similarity. Another remarkable observation was the wide expression of mTLR1-3 mRNAs in all tissues. Among the analyzed tissues, skeletal muscle was revealed to being the lowest repertoire of mTLR expression. Additionally, mink PBMCs exposed to the canine distemper virus revealed significant upregulation of mTLR2, mTLR4, mTLR7, and mTLR8 mRNAs, indicating that mTLRs have a role in innate immunity in the mink. Collectively, our results are the first to establish the basic expression patterns of mTLRs and the relationship between mTLRs and a virus, which will contribute to better understanding of the evolution and the functions of mTLRs in the innate immune system in minks.

A Suggestion for the Strategic Choice of Seoul to be a Network Center in Northeast Asia

  • Ahn, Kun-Hyuck;Ohn, Yeong-Te
    • Journal of the Korean Regional Science Association
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    • v.15 no.2
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    • pp.155-187
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    • 1999
  • The East Asian Region has experienced remarkable economic growth and transformation of interurban networking over the past three decades, and urban competiti veness for a networking hub in this region has become a critical issue confronting cities. Competitiveness of the Seoul capital region for a networking hub in Northeast Asia is outstripped by other competing cities in East Asia, notwithstanding its geo-politically and geo-economically advantageous location in this region. In this paper, we aim to appraise the Seoul capital region's competitiveness in terms of logistics distribution, financial function and logistics distribution, financial function and agglomeration of transnational corporations (especially of RHOs and other managerial functions), and to advance the networking strategies of the region for a Northeast Asia hyb. As a result of analysis, we suggest that the Seoul capital region be developed as a Northeast Asian center for regional headquarters or leading global corporations and financial services for being a strategic nodal point in Northeast Asia in the 21st century. A recent survey shows that where to locate an RHQ is influenced by various factors, such as potential market and manufacturing site in the city's hinterland, quality of life, such things as culture, health, safety, education, a well-educated, English-speaking population, reliable air transport, state-of-the-art communications, and an active policy to offer foreign companies generous incentives. The Seoul capital region, which is located at a strategic nodal point advantageous as a springboard for its Northeast Asian hinterland, cannot meet the other conditions mentioned above. To overcome these drawbacks in attracting transnational capital and to create competitiveness as a strategic hub of RHQs in Northeast Asia, it is urgent to initiate a structural reform of the Korean economy, politics, and overall society, to minimize the regulation of FDI, and to provide various incentives for foreign investment. Moreover, we propose the construction of an 'International Business Town' in the Seoul capital region, as a medium to intermediate these strategies and to shape them in a spatial scale. The projected 'International Business Town(IBT)' will be a 'free city' open to international business in which liberal economic activities are guaranteed by special legislation and administration, infrastructures needed for international and improved accessibility to the airport are furnished, and the preference of foreign high-income investors for cultural and living environment are satisfactorily met. IBT is conspicuously differentiated from a raft of other cities' incentives in that it combines deregulation and incentive programs to attract the investment of transnational capital, with a spatial program of offering an urban environment preferred by the high-income investors for cultural and living environment are satisfactorily met. IBT is conspicuously differentiated from a raft of other cities' incentives in that it combines deregulation and incentive programs to attract the investment of transnational capita, with a spatial program of offering an urban environment preferred by the high-income and managerial class. Furthermore, it can be an excellent way of overcoming the xenophobia that has spread among the Korean population by concentrating foreign businesses and their lifestyles in a specific foreign businesses and their lifestyles in a specific zone. In conclusion, 'International Business Town', in line with other legislative and administrative incentive programs, will function as a driving force to make the Seoul capital regional more competitive as a regional business hub in Northeast Asia.

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Estimation of Road-Network Performance and Resilience According to the Strength of a Disaster (재난 강도에 따른 도로 네트워크의 성능 및 회복력 산정 방안)

  • Jung, Hoyong;Choi, Seunghyun;Do, Myungsik
    • International Journal of Highway Engineering
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    • v.20 no.1
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    • pp.35-45
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    • 2018
  • PURPOSES : This study examines the performance changes of road networks according to the strength of a disaster, and proposes a method for estimating the quantitative resilience according to the road-network performance changes and damage scale. This study also selected high-influence road sections, according to disasters targeting the road network, and aimed to analyze their hazard resilience from the network aspect through a scenario analysis of the damage recovery after a disaster occurred. METHODS : The analysis was conducted targeting Sejong City in South Korea. The disaster situation was set up using the TransCAD and VISSIM traffic-simulation software. First, the study analyzed how road-network damage changed the user's travel pattern and travel time, and how it affected the complete network. Secondly, the functional aspects of the road networks were analyzed using quantitative resilience. Finally, based on the road-network performance change and resilience, priority-management road sections were selected. RESULTS : According to the analysis results, when a road section has relatively low connectivity and low traffic, its effect on the complete network is insignificant. Moreover, certain road sections with relatively high importance can suffer a performance loss from major damage, for e.g., sections where bridges, tunnels, or underground roads are located, roads where no bypasses exist or they exist far from the concerned road, including entrances and exits to suburban areas. Relatively important roads have the potential to significantly degrade the network performance when a disaster occurs. Because of the high risk of delays or isolation, they may lead to secondary damage. Thus, it is necessary to manage the roads to maintain their performance. CONCLUSIONS : As a baseline study to establish measures for traffic prevention, this study considered the performance of a road network, selected high-influence road sections within the road network, and analyzed the quantitative resilience of the road network according to scenarios. The road users' passage-pattern changes were analyzed through simulation analysis using the User Equilibrium model. Based on the analysis results, the resilience in each scenario was examined and compared. Sections where a road's performance loss had a significant influence on the network were targeted. The study results were judged to become basic research data for establishing response plans to restore the original functions and performance of the destroyed and damage road networks, and for selecting maintenance priorities.