• Steel and Composite Structures
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• 제37권3호
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• pp.273-289
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• 2020

Due to the unique construction method of modular steel buildings (MSBs) with units prefabricated fully off the site and assembled quickly on the site, the inter-module connection for easy operation and overall performance of the system were key issues. However, it was a lack of relevant research on the system-level performance of MSBs. This study investigated the seismic performance of two-storey modular steel structure with a proposed vertical rotary inter-module connection. Three full-scale quasi-static tests, with and without corrugated steel plate and its combination, were carried out to evaluate and compare their seismic behaviour. The hysteretic performance, skeleton curves, ductile performance, stiffness degradation, energy dissipation capacity, and deformation pattern were clarified. The results showed that good ductility and plastic deformation ability of such modular steel structures. Two lateral-force resistance mechanisms with different layout combinations were also discussed in detail. The corrugated steel plate could significantly improve the lateral stiffness and bearing capacity of the modular steel structure. The cooperative working mechanism of modules and inter-module connections was further analyzed. When the lateral stiffness of upper and lower modular structures was close, limited bending moment transfer may be considered for the inter-module connection. While a large lateral stiffness difference existed initially between the upper and lower structures, an obvious gap occurred at the inter-module connection, and this gap may significantly influence the bending moments transferred by the inter-module connections. Meanwhile, several design recommendations of inter-module connections were also given for the application of MSBs.

• 대한한의학회지
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• 제24권2호
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• pp.138-147
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• 2003

Objectives : In this study, we investigated the mechanism by which Chelidonium majus (CM) regulates nitric oxide (NO) production. Methods : Using mouse peritoneal macrophages, the mechanism by which CM regulates NO or tumor necrosis $factor-{\alpha}(TNF-{\alpha})$ production was examined. NO release was measured by the Griess method. $TNF-{\alpha}$ production was measured by the ELISA method. The protein extracts were prepared and samples were analyzed for the inducible NOS(iNOS) expression and nuclear factor kappa $B(NF-{\kappa}B)$ activation by Western blotting. Results : When CM was used in combination with recombinant $interferon-{\gamma}{\;}(rIFN-{\gamma})$, there was a marked cooperative induction of NO production. CM had an effect on NO production by itself. The expression of the iNOS gene was increased in $rIFN-{\gamma}$ plus CM-stimulated peritoneal macrophages and almost completely inhibited by pre-treatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of $NF-{\kappa}B$. The $NF-{\kappa}B$ activation was increased in rIFN-{\gamma} plus CM-induced peritoneal macrophages. The increased production of NO from $rIFN-{\gamma}$ plus CM-stimulated peritoneal rnacrophages was decreased by the treatment with $N^{G}-monomethyl-{_L}-arginine{\;}(N^{G}MMA){\;}N^{\alpha}-Tosyl-Phe$ chloromethyl ketone (TPCK) , and was almost completely inhibited by pre-treatment with PDTC. Furthermore, treatment with CM alone or rIFN-{\gamma} plus CM in peritoneal macrophages caused a significant increase in $TNF-{\alpha}$ production. PDTC decreased CM-induced $TNF-{\alpha}$ production significantly. After CM treatment in HT-29 or AGS cells, cell viability decreased. Conclusions : These findings demonstrate that CM increases the production of NO and $TNF-{\alpha}{\;}by{\;}rIFN-{\gamma}-primed$ macrophages and suggest that NF-B plays a critical role in mediating these effects of CM.

• 대한한의학회지
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• 제19권2호
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• pp.36-49
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• 1998

HERBA SAURURI (HS) has been known to use antiinflammatory drug. To investigated the mechanism of HS-induced NO synthesis, I evaluated the ability of protein kinase C (PKC) inhibitors such as staurosporine (STSN) or polyymyxin B to block HS-induced effects. HS alone had only a small effect, whereas in combination with $rIFN-{\gamma}$, markedly increased NO synthesis in a dose dependent manner. STSN and polymyxin B decreased NO synthesis, which had been induced by $rIFN-{\gamma}$, plus HS. Furthermore, prolonged incubation of the cells with phorbol ester, which down-regulates PKC activity abolished synergistic cooperative effect of HS with $rIFN-{\gamma}$ on NO synthesis. STSN and Polymyxin B potently inhibited HS-induced $TNF-{\alpha}$ secretion by $rIFN-{\gamma}$ plus HS. However, $rIFN-{\gamma}$ plus $TNF-{\alpha}-induced$ NO synthesis was not blocked by STSN or polymyxin B. On the other hand, tyrosine kinase inhibitor, genistein, blocked the NO synthesis and $TNF-{\alpha}$ secretion by $rIFN-{\gamma}$ plus HS. In conlusion, the present results strongly suggest that the capacity of HS to increase NO synthesis from $rIFN-{\gamma}-primed$ macrophages is the result of HS-induced $TNF-{\alpha}$ secretion via the signal transduction pathway of PKC and tyrosine kinase.

• 한국콘텐츠학회논문지
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• 제19권12호
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• pp.38-56
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• 2019

기후변화의 지역적 광역성과 장기성으로 기후변화 문제는 일개 국가의 노력만으로는 해결할 수 없는 전지구적 난제로 자리 잡고 있다. 따라서 수직적으로 전세계(global), 지역(regional), 국가(national), 지방(local) 수준의 수직적 거버넌스가 중요하다. 또한 각 수준에서 정부, 기업, 민간의 수평적 거버넌스가 조화롭게 작동할 때 복잡한 기후변화문제에 대한 해결 실마리를 얻을 수 있다. 본 연구에서는 1990년부터 2018년까지 29년간 일간신문에서 기후변화라는 주제어를 가진 약 24,000건의 기사에 나타난 기후변화에 대한 수직적·수평적 거버넌스와 이슈트렌드 등을 분석하였다. 분석결과 우리나라에서는 수직적 측면에서 글로벌 기후변화 이슈를 중앙정부는 적극적으로 참여하고 있으나, 동북아와 같은 지역적 논의는 거의 없었다. 수평적 측면에서는 정부 중심의 논의가 주류를 이루고 있고 민간 시민단체의 참여나 기업의 참여는 부족하였다. 향후 기후변화에 효과적으로 대응하기 위해서는 수직적 측면에서는 지역적 협력에 대한 논의와 함께 기후변화가 직접적으로 행동에 옮겨질 수 있는 지방수준에서 실질적인 논의가 활발히 이루어져야 한다. 또한 수평적인 측면에서는 개발시대의 관주도적 태도에서 벗어나 시장메커니즘을 적극적으로 활용할 수 있는 방안과 시민사회의 참여를 유도할 수 있는 방안이 마련되어야 한다. 이를 위해 기후변화대응 기본법 등의 제정을 통한 제도적 정비를 제안하였다.

• 한국과 국제사회
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• 제3권2호
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• pp.131-154
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• 2019

국가가 자주권을 행사하는 것은 전략문화와 강한 상관관계가 있지만 국가의 전략문화의 분류에 대해서는 학자마다 견해가 다르다. 중국 서부의 가장 중요한 인접국가 중 하나인 파키스탄은 중국의 든든한 파트너로서 파키스탄의 전략문화를 이해하는 것은 파키스탄의 국가정책과 국가가 자주권을 행사하는 행위를 이해하는 데 도움이 될 뿐만 아니라 중국과 파키스탄 양국의 협력관계를 심화시키는 데도 도움이 된다. 저자는 지리, 사회, 경제, 문화, 역사, 군사 등의 관점에서 볼 때 파키스탄의 전략적 문화 형성의 메커니즘은 주로 지정학적 환경, 생산방식, 생활방식, 문화적 전통, 역사적 경험과 대외 관계 등 네 가지 요인의 영향을 받는다. 분석 결과로 파키스탄의 전략 문화는 이슬람에 의해 형성되어 왔고, 대외 지향적인 전략 문화로 분류될 수 있으며 국가가 자주권을 행사하는 거도 이슬람적인 색채가 강하다.

• Steel and Composite Structures
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• 제50권1호
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• pp.107-122
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• 2024

Following an internal column failure, adjacent double-span beams above the failed column will play a critical role in the load transfer and internal force redistribution within the remaining structure, and the span-to-depth ratios of double-span beams significantly influence the structural resistance capacity against progressive collapse. Most existing studies have focused on the collapse-resistant performances of single-story symmetric structures, whereas limited published works are available on the collapse resistances of multi-story steel frames with unequal spans. To this end, in this study, numerical models based on shell elements were employed to investigate the structural behavior of multi-story steel frames with unequal spans. The simulation models were validated using the previous experimental results obtained for single- and two-story steel frames, and the load-displacement responses and internal force development of unequal-span three-story steel frames under three cases were comprehensively analyzed. In addition, the specific contributions of the different mechanism resistances of unequal-span, double-span beams of each story were separated quantitatively using the energy equilibrium theory, with an aim to gain a deeper level of understanding of the load-resistance mechanisms in the unequal-span steel frames. The results showed that the axial and flexural mechanism resistances were determined by the span ratio and linear stiffness ratio of double-span beams, respectively.

• Bulletin of the Korean Chemical Society
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• 제31권2호
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• pp.435-441
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• 2010

We report the preparation and characterization of a new and water soluble complex of palladium(II) with 1,10- phenanthroline and butyldithiocarbamate ligands. This compound has been studied through spectroscopic techniques, $^1H$ NMR, IR, electronic spectra and elemental analysis and conductivity measurements. The complex shows 50% cytotoxic concentration ($Ic_{50}$) value against chronic myelogenous leukemia cell line, K562, much lower than that of cisplatin. Thus the mode of binding of this complex to calf thymus DNA have been extensively investigated by isothermal titration UV-visible spectrophotometry, fluorescence, gel filteration and other methods. UV-visible studies show that the complex exhibits cooperative binding with DNA and remarkably denatures the DNA at extremely low concentration ($~13\;{\mu}M$). Fluorescence studies indicate that the complex intercalate into DNA. Gel filtration studies suggest that the binding of Pd(II) complex with DNA is strong enough that it does not readily break. In these interaction studies, several thermodynamic and binding parameters are also determined which may reflect the mechanism of action of this type of compound with DNA.

• 한국산업융합학회 논문집
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• 제18권2호
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• pp.99-109
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• 2015

This study proposes a new approach to analyze the impedance and the elasticity of a serial chain of spring-damper system, areal-time collision-free trajectory generation algorithm is proposed. The reference points on a trajectory connected by the spring-damper system have a mechanism for self-position adjustment to solve a collision problem by the impedance, and the local adjustment of each reference point is propagated through the elasticity to a real robot at the end of the spring-damper system. As a result, the overall trajectory consisting of the reference points becomes free of collision with environmental obstacles and efficient having the shortest distance as possible. In this process,, the reference points connected by the spring-damper system take role of virtual robot as global guidance for a real robot, and a cooperative is carried out by the system of robots. A control technology is proposed to implement for mobile robot.

• 한국분말재료학회지
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• 제15권3호
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• pp.210-213
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• 2008

Elongated CdSe nanoparticles with a diameter of 3-7nm have been successfully synthesized using two surfactants of trioctylphospine (TOP) and hexadecylamine (HDA) at $160^{\circ}C$. The formation of elongated CdSe nanoparticles is possibly due to the cooperative effects from both the different binding capability of two surfactants (TOP and HDA) and intrinsically anisotropic crystal structure of the CdSe. The electron diffraction pattern of CdSe nanoparticles revealed the formation of wurzite phase. The CdSe samples showed red-shifted wavelength from 560 to 580nm with increasing the refluxing time due to the gradual growth of CdSe nanoparticles. The relatively broad absorption band can be attributed to the surface state of CdSe nanoparticles. The possible formation mechanism of elongated CdSe nanoparticles was proposed and the characteristics of CdSe have been discussed as well.

• Environmental Engineering Research
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• 제22권1호
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• pp.95-107
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• 2017

Adsorption equilibrium and kinetic behavior of two toxic heavy metals hexavalent chromium [Cr(VI)] and mercury [Hg(II)] on mustard oil cake (MOC) was studied. Isotherm of total chromium was of concave type (S1 type) suggesting cooperative adsorption. Total chromium adsorption followed BET isotherm model. Isotherm of Hg(II) was of L3 type with monolayer followed by multilayer formation due to blockage of pores of MOC at lower concentration of Hg(II). Combined BET-Langmuir and BET-Freundlich models were appropriate to predict Hg(II) adsorption data on MOC. Boyd's model confirmed that external mass transfer was rate limiting step for both total chromium and Hg(II) adsorptions with average diffusivity of $1.09{\times}10^{-16}$ and $0.97m^2/sec$, respectively. Desorption was more than 60% with Hg(II), but poor with chromium. The optimum pH for adsorptions of total chromium and Hg(II) were 2-3 and 5, respectively. At strong acidic pH, Cr(VI) was adsorbed by ion exchange mechanism and after adsorption reduced to Cr(III) and remained on MOC surface. Hg(II) removal was achieved by complexation of $HgCl_2$ with deprotonated amine ($-NH_2$) and carboxyl (COO-) groups of MOC.