• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.15-15
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• 2011

As you know, boron compounds, borax ($Na_2B_4O_5(OH)_4{\cdot}8H_2O$) etc. were known thousands of years ago. As for natural boron, it has two naturally occurring and stable isotopes, boron 11 ($^{11}B$) and boron 10 ($^{10}B$). The neutron absorption $^{10}B$ is included about 19~20% with 80~81% $^{11}B$. Boron is similar to carbon in its capability to form stable covalently bonded molecular networks. The mass difference results in a wide range of ${\beta}$ values between the $^{11}B$ and $^{10}B$. The $^{10}B$ isotope, stable with 5 neutrons is excellent at capturing thermal neutrons. For example, it is possible to decrease a thermal neutron required for the nuclear reaction of uranium 235 ($^{235}U$). If $^{10}B$ absorbs a neutron ($^1n$), it will change to $^7Li+^1{\alpha}$ (${\alpha}$ ray, like $^4He$) with prompt ${\gamma}$ ray from $^{11}B$ $^{11}B$ (equation 1). $$^{10}B+^1n\;{\rightarrow}\;^{11}B\;{\rightarrow}\; prompt \;{\gamma}\;ray (478 keV), \;^7Li+4{\alpha}\;(4He)\;\;\;\;{\cdots}\; (1)$$ If about 1% boron is added to stainless steel, it is known that a neutron shielding effect will be 3 times the boron free steel. Enriched boron or $^{10}B$ is used in both radiation shielding and in boron neutron capture therapy. Then, $^{10}B$ is used for reactivity control and in emergency shutdown systems in nuclear reactors. Furthermore, boron carbide, $B_4C$, is used as the charge of a nuclear fission reaction control rod material and neutron cover material for nuclear reactors. The $B_4C$ powder of natural B composition is used as a charge of a control material of a boiling water reactor (BWR) which occupies commercial power reactors in nuclear power generation. The $B_4C$ sintered body which adjusted $^{10}B$ concentration is used as a charge of a control material of the fast breeder reactor (FBR) currently developed aiming at establishment of a nuclear fuel cycle. In this study for new boron compound, silicon boride ceramics for capturing thermal neutrons, preparation and characterization of both silicon tetraboride ($SiB_4$) and silicon hexaboride ($SiB_6$) and ceramics produced by sintering were investigated in order to determine the suitability of this material for nuclear power generation. The relative density increased with increasing sintering temperature. With a sintering temperature of 1,923 K, a sintered body having a relative density of more than 99% was obtained. The Vickers hardness increased with increasing sintering temperature. The best result was a Vickers hardness of 28 GPa for the $SiB_6$ sintered at 1,923K for 1 h. The high temperature Vickers hardness of the $SiB_6$ sintered body changed from 28 to 12 GPa in the temperature range of room temperature to 1,273 K. The thermal conductivity of the SiB6 sintered body changed from 9.1 to 2.4 W/mK in the range of room temperature to 1,273 K.

• 한국식품과학회지
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• 제34권5호
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• pp.873-878
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• 2002

재래식 메주의 맛을 지닌 코오지의 산업화를 유도하기 위해 재래식 메주에서 분리한 세균과 곰팡이를 이용한 코오지의 특성을 조사하였다. 코오지 제조에 선정된 곰팡이와 세균은 재래식 메주에서 분리한 Bacillus subtilis B-4와 Aspergillus oryzae F-5로, B. subtilis B-4와 A. oryzae F-5는 amylase와 protease 등의 효소분비능이 우수한 것이었다. B. subtilis B-4와 A. oryzae F-5를 각각 코오지 제조에 이용한 결과 색깔은 B. subtilis B-4로 제조한 코오지가 A. oryzae F-5로 제조한 코오지에 비해 약간 어두운 편이었고, 효소분비능은 B. subtilis B-4로 제조한 코오지가 A. oryzae F-5로 제조한 코오지에 비해 우수한 편이었다. 제국이 끝난 코오지에 대한 맛, 향, 색깔 및 전반적인 기호도에 대한 관능검사에서는 B. subtilis B-4로 제조한 코오지가 A. oryzae F-5로 제조한 코오지에 비해 색깔을 제외한 모든 면에서 높은 점수를 얻고 있었다. 수분활성도가 제국에 미치는 영향을 조사한 결과 수분활성도를 조절하여 제조한 코오지가 색도, 효소분비능, 생균수 및 관능검사에서 우수한 것으로 나타났다.

• 대한수학회보
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• 제58권1호
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• pp.31-46
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• 2021

Let a and b be positive integers, and let V (G), ��(G), and ��2(G) be the vertex set of a graph G, the minimum degree of G, and the minimum degree sum of two non-adjacent vertices in V (G), respectively. An even [a, b]-factor of a graph G is a spanning subgraph H such that for every vertex v ∈ V (G), dH(v) is even and a ≤ dH(v) ≤ b, where dH(v) is the degree of v in H. Matsuda conjectured that if G is an n-vertex 2-edge-connected graph such that $n{\geq}2a+b+{\frac{a^2-3a}{b}}-2$, ��(G) ≥ a, and ${\sigma}_2(G){\geq}{\frac{2an}{a+b}}$, then G has an even [a, b]-factor. In this paper, we provide counterexamples, which are highly connected. Furthermore, we give sharp sufficient conditions for a graph to have an even [a, b]-factor. For even an, we conjecture a lower bound for the largest eigenvalue in an n-vertex graph to have an [a, b]-factor.

• Journal of applied mathematics & informatics
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• 제42권3호
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• pp.635-646
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• 2024

In this research work, we introduce and investigate four innovative types of soft spaces, pushing the boundaries of traditional spatial concepts. These new types of soft spaces are named as soft T_b space, soft T^#_b space, soft T^##_b space and soft_αT^#_b space. Through rigorous analysis and experimentation, we uncover and propose distinct characteristics that define and differentiate these spaces. In this research work, we have established that every soft $T_{\frac{1}{2}}$ space is a soft _αT^#_b space, every soft T_b space is a soft _αT^#_b space, every soft T^#_b space is a soft _αT^#_b space, every soft T_b space is a soft T^#_b space, every soft T^#_b space is a soft T^##_b space, every soft $T_{\frac{1}{2}}$ space is a soft ^#T_b space and every soft T_b space is a soft #T_b space.

• International Journal of Industrial Entomology and Biomaterials
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• 제23권1호
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• pp.167-174
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• 2011

The large bumblebee $Bombus$ $terrestris$, indigenous to Europe and adjacent areas and used extensively for high-value crop pollination, has been artificially introduced to several parts of the world. Here we show the occurrence of interspecific hybridization between the bumblebee species $B.$ $hypocrita$ $sapporoensia$ and $B.$ $terrestris$ under laboratory conditions. The mating and oviposition percentages resulting from the interspecific hybridization of a $B.$ $terrestris$ queen with a $B.$ $h.$ $sapporoensis$ male were higher than those resulting from the intraspecific mating of $B.$ $h.$ $sapporoensis$. Furthermore, a competitive copulation experiment indicated that the mating of $B.$ $h.$ $sapporoensis$ males with $B.$ $terrestris$ queens was 1.2-fold more frequent than the mating of these males with $B.$ $h.$ $sapporoensis$ queens. The interspecific hybridization of a $B.$ $terrestris$ queen with a $B.$ $h.$ $sapporoensis$ male produced either $B.$ $terrestris$ workers or the $B.$ $terrestris$ male phenotype, and the hybridization of a $B.$ $h.$ $sapporoensis$ queen with a $B.$ $terrestris$ male produced $B.$ $h.$ $sapporoensis$ males. Our results indicated that interspecific hybridization occurred between $B.$ $h.$ $sapporoensis$ and $B.$ $terrestris$. These results suggest that such hybridization will have a negative competitive impact and will cause genetic contamination of native bumblebees.

• Journal of Community Nutrition
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• 제7권2호
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• pp.79-84
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• 2005

A vitamin B-6 (B-6) intake higher than the current Recommended Dietary Allowance (RDA) has been found to provide an improvement in immune system. Seven premenopausal women consumed their usual diet with the exception of foods relatively high in vitamin B-6 for a total of 27 d. After 7 d, all subjects received a multivitamin supplement containing 2mg B-6 and 4 subjects were given an additional 50mg of B-6 supplement for 20 d. Lymphocyte response to phytohemagglutinin (PHA) was measured before and after the supplementation. To determine the effect of different forms of B-6 on lymphocyte proliferation, cell culture media supplemented with pyridoxal (PL) and PLP, as well as B-6 free media, were tested. A 50mg B-6 supplement significantly increased vitamin B-6 status. There was no further enhancement on lymphocyte proliferation when subjects were taking an additional 50mg of vitamin B-6 supplement. In general, lymphocyte proliferation in media with either PLP or PL did not show any prominent difference. These [m-dings suggest that there may be no further benefits of a B-6 dose beyond twice that of the current RDA on lymphocyte proliferation. Further studies are necessary to examine the effect of the B-6 intake level on activities of enzymes involved in cellular B-6 metabolism in lymphocytes to provide substantial insight into the mechanisms underlying the role of B-6 in the lymphocyte proliferation.

• Animal cells and systems
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• 제5권3호
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• pp.247-251
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• 2001

Differentiating HiB5 cells, a rat hippocampal cell line, expressed neuregulins and showed constitutive activation of a neuregulin receptor, ErbB2, suggesting development of a neuregulin autocrine loop. RT-PCR analyses indicated that HiB5 cells produced SMDF and NDF, but not GGF, during the differentiation. None of neuregulin isoforms were detected in proliferating HiB5 cells. The neuregulins in HiBS cells, at least in part, are the $\beta$-isoforms of which the most of neuronal neuregulin isoforms are. The expression of SMDF and NDF was enhanced by PDGF and bFGF that promote cell survival and differentiation, suggesting a close relationship between the synthesis of neuregulins and the differentiation process. HiB5 cells have ErbB2 and ErbB4, but not ErbB3 receptors. Constitutive tyrosine phosphorylation of ErbB2 was detected in HiB5 cells that had not been exposed to exogenous GGF.

• 한국항행학회논문지
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• 제12권6호
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• pp.539-547
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• 2008

본 논문에서는 연구용 ADS-B/TIS-B Validation Testbed(AVT)설계를 위한 기초 결과에 대하여 살펴본다. ADS-B는 GNSS와 디지털 데리터링크를 활용한 새로운 항공감시 개념이다. ADS-B는 종속적인 감시 개념이기 때문에 ADS-B송수신기를 장착하지 않은 항공기에 대한 감시 정보는 획득이 불가능하다. 기존의 이차감시레이더를 사용하여 획득한 감시정보를 제공하는 개념이 AIS-B이다. AVT는 ADS-B 및 ATS-B 개념을 기반으로 한 차세대 위성항행시스템의 감시 플랫폼이라는 의의가 있다.

• 경영과학
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• 제11권1호
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• pp.129-144
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• 1994

B-ISDN(Broadband Integrated Services Digital Network)which is defined as a service or system requiring transmission channels capable of supporting rates above 1.5 Mbps has emerged as a new future telecommunication infrastructure. B-ISDN can integrate a wide range of services and the success of B-ISDN is crucially dependent on the development of user-needing application services. The purpose of this study is the conceptual development of B-ISDN application services. We survey on the kinds of B-ISDN service, classify application areas by user groups, and develop B-ISDN application services. Finally we categorize B-ISDN application services by their application areas and necessary services.

• 한국수학사학회지
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• 제25권3호
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• pp.29-39
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• 2012

선형논리는 현대 증명이론의 산물로서 1987년 프랑스 Marseille대학 Jean-Yves Girard 교수가 프로그래밍 언어의 개발을 위해 직관주의 논리학 (Intuitional logic) 을 정교하게 보완하여 고안한 새로운 논리학이다. 그래서 선형논리의 연결사들은 정보배열 (Sequentiality)과 병행처리 (Parallel computation) 등 정보처리와 관련된 해석을 갖는다. 예컨대, A${\otimes}$B는 두 과정 A와 B를 차례차례 수행하는 것을 나타내고, A&B는 내적미결정과 관련되어 관찰자가 A 또는 B를 선택할 수 있으며, A${\oplus}$B는 외적인 미결정으로서, 관찰자는 A 또는 B라는 사실을 알지만 어느 것이 될지는 알지 못한다. 그리고 A${\wp}$B는 A과정과 B과정의 병행처리를 의미한다. 선형부정은 동시화(Synchronization)를 나타내어, 하나의 과정 A가 수행되기 위해서는 A와 $A^{\bot}$가 동시에 이루어져야 한다. 국내에 선형논리에 대한 연구가 활성화되지 않아서 이 글은 이에 대한 관심을 제고하기 위해 우선 선형논리의 통사론만을 취급했으며, 의미론과 증명망 등은 차후의 연구에서 다루고자 한다.