• Title/Summary/Keyword: Environment strength

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Pseudo type HIV-1 Particles Carrying CD4

  • Park, Seung-Won;Kim, Tai-Gyu;You, Ji-Chang;Schubert, Manfred;Paik, Soon-Young
    • The Journal of Korean Society of Virology
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    • v.30 no.1
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    • pp.83-99
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    • 2000
  • A defective HIV-1 helper virus DNA, pHyPC, was assembled by deleting the RNA packaging signal, env, nef and the 3'LTR sequences. HIV-1 like virus particles that carry the HIV-1 receptor, CD4 were generated by co expression of pHyPC and plasmid DNAs encoding different chimeric CD4 proteins. The CD4 particles, sharing the CD4 ectodomain, precisely fused to different membrane anchors. CD4(+) particles specifically bound to HIV-1 Env expressing cells, but any signs of infection into these cells were not detected. Binding was only partially blocked by either polyclonal anti-CD4 antibodies or by high concentrations of soluble CD4. Surprisingly, CD4(+) particles also adsorbed to HeLa, CHO, NIH3T3 and COS-7 cells in the absence of HIV-1 Env expression. Adsorption was comparable in strength and speed to the highly specific CD4-Env interaction. CD4(-) particles exhibited only background levels of binding. Cell binding was CD4. dependent, but it was independent of the cell type from which the CD4(+) particles originated. Interestingly, CD4-dependent/Env-independent binding was only found when CD4 was present on virus particles. This suggests that the micro-environment of CD4 on virus particles uniquely expose this new cell binding activity. Its high affinity could explain in part why infection of Env(+) cells by CD4(+) particles was not detected. Further experiments will be required to evaluate whether this strong membrane interaction could represent one step in the multiple-step viral entry process.

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Development of Investment Casting Technique using R/P Master Model (R/P 마스터모델을 활용한 정밀주조 공정기술의 개발)

  • Im, Yong-Gwan;Chung, Sung-Il;Jeong, Hae-Do
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.6
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    • pp.52-57
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    • 1999
  • Funtional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported by song etc. But a system which can build directly 3D parts of high performance functional material as metal part would need long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we tranlsated the wax patterns to numerous metal prototypes by new investment casting process combined conventional investment casting with rapid pototyping & rapid tooling process. with this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P part to metal part.

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Evaluation of the properties and the papermaking applicability of the residue originated from the anaerobic digestion of livestock manure (축산분뇨 혐기소화 잔재물의 특성 및 초지 적용성 평가)

  • Kim, Seung Min;Jung, Woong-Gi;Sung, Yong Joo;Ahn, Hee-Kwon;Kim, Dong Sung;Yoon, Do-Hyun;Kim, Dong-Seop;Jung, Hwa Gwang
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.46 no.3
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    • pp.58-64
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    • 2014
  • Management of organic waste such as livestock manure has been considered as very important issue in terms of the environment. The anaerobic digestion of livestock manure become more attractive treatment method and has been widely applied. In this work, the properties of the residue after the anaerobic digestion of livestock manure was evaluated for providing the basic data to develop new application. The lignin and the ash contents of the residue were much higher than those of other biomass such as wood. The components of the residue were also analyzed with SEM-EDS and Elemental Analyzer. The addition of the residue into the handsheet paper resulted in the higher bulk and he higher air permeability with the loss of the strength properties. The water holding capacity of the handsheet were increased until the 40 % addition of the residue.

The Effects of Hot Corrosion on the Creep Rupture Properties of Boiler Tube Material (보일러 管材料의 크리프破斷特性에 미치는 고온부식의 影響)

  • 오세욱;박인석;강상훈
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.2
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    • pp.236-242
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    • 1989
  • In order to investigate the effects of hot corrosion on the creep rupture properties and creep life of 304 stainless steel being used as tube materials of heavy oil fired boiler, the creep rupture tests were carried out at temperature 630.deg.C, 690.deg.C and 750.deg.C in static air for the specimens with or without coating of double layer corrosives according to the new hot corrosion test method simulating the situation commonly observed on superheater tubes of the actual boiler. The double layer corrosives are 85% V$_{2}$O$_{5}$ + 10% Na$_{2}$So$_{4}$ + 5% Fe$_{2}$O$_{3}$ as the inner layer corrosive being once melted at 900.deg. C and crushed to powder, and 10% V$_{2}$O$_{5}$ + 85% Na$_{2}$SO$_{4}$ +5% Fe$_{2}$O$_{3}$ as the outer layer corrosive. As results, in the specimen coated with the double layer corrosives, the rupture strength was extremely lowered and showed a large difference each other. The rupture ductility also lowered remarkably as a result of the brittle fracture mode due to hot corrosion. These results indicate that hot corrosion could essentially alter the creep fracture mechanism. From the metallographic observation, it was clarified that the rupture life of 304 stainless steel subjected to hot corrosion was chiefly determined by the behavior of the aggressive intergranular penetration of sulfides.des.

Resident-Driven Rural Village Plan Based on Ecological Rural Amenity: Focused on Busu Area, Boeun-gun, South Korea (생태적 농촌어메니티 기반 주민주도형 농촌마을종합계획 -보은군 회인면 부수권역 '하얀민들레 생태마을'을 중심으로-)

  • Ban, Yong-Un;Youn, Joong-Shuk;Woo, Hye-Mi;Han, Kyung-Min;Baek, Jong-In
    • Journal of Korean Society of Rural Planning
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    • v.16 no.4
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    • pp.157-169
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    • 2010
  • This study has intended to devise a comprehensive rural planning, driven by residents based on ecological rural amenity paradigm for Busu area, Boeun-gun, South Korea. To reach the goal, this study has performed the following processes. First, we have analyzed the elements of threat, opportunity, weakness, and strength in both inside and outside village through 'SWOT analysis. Second, through strategic analysis and consultation, we have proposed developmental directions of Busu area. Third, based on an ecological rural amenity planning system composed of ecological economy system, ecological environment system, ecological history-culture system, ecological image system, and ecological society system, we have suggested research projects of each system Fourth, we selected projects through a general meeting with all stakeholders. Fifth, the selected projects were applied to Busu area by village residents and experts. Finally, the projects, which were appraised and revised by experts, residents, and governmental officers, were composed of ecological scenic agriculture center, resident's site for city dweller, energy independent village, eco-road, eco-pond, ecological park and parking lot, restoration of traditional culture, zone of ecological scenic agriculture, eco-tunnel, eco-fence, landmark, corporate identity, community center, forum and seminar, and education for residents' empowerment.

Critical Buckling Temperatures of Anisotropic Laminated Composite Plates considering a Higher-order Shear Deformation (고차전단변형을 고려한 비등방성 적층복합판의 임계좌굴온도)

  • Han, Seong Cheon;Yoon, Seok Ho;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.10 no.2 s.35
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    • pp.201-209
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    • 1998
  • The presence of elevated temperature can alter significantly the structural response of fibre-reinforced laminated composites. A thermal environment causes degradation in both strength and constitutive properties, particularly in the case of fibre-reinforced polymeric composites. Furthermore, associated thermal expansion, either alone or in combination with mechanically induced deformation, can result in buckling, large deflections, and excessively high stress levels. Consequently, it is often imperative to consider environmental effects in the analysis and design of laminated systems. Exact analytical solutions of higher-order shear deformation theory is developed to study the thermal buckling of cross-ply and antisymmetric angle-ply rectangular plates. The buckling behavior of moderately thick cross-ply and antisymmetric angle-ply laminates that are simply supported and subject to a uniform temperature rise is analyzed. Numerical results are presented for fiber-reinforced laminates and show the effects of ply orientation, number of layers, plate thickness, and aspects ratio on the critical buckling temperature and compared with those obtained using the classical and first-order shear deformation theory.

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A Study on Electrochemical Polarization Test for Embrittlement Damage Evaluation of Aged Cr-Mo Steel (Cr-Mo강 시효재의 취화손상 평가를 위한 전기화학적 분극시험에 관한 연구)

  • Yu, Hyo-Sun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.19 no.6
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    • pp.411-419
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    • 1999
  • It has been well recognized that a long term service at elevated temperature of $350^{\circ}C{\sim}550^{\circ}C$ induces embrittlement damage due to carbide precipitation and/or P, Sb and Sn segregation at grain boundaries and thereby deteriorates the grain boundary strength of heat resisting components in the energy-related plants. Therefore, it is very important to assess quantitatively the extent of embrittlement damage of heat resisting components to secure the reliable and efficient service condition and to prevent brittle failure in service. However, because fracture tests are limited in size and number of specimen obtained from the structural components, nondestructive test method is required. In this study, the optimum electrochemical parameters are investigated and discussed to evaluate nondestructive embrittlement damage for aged 2.25Cr-1Mo steels by means of electrochemical polarization test method (ECPTM) in proper corrosive environment. In addition, the electrochemical test results are compared with embrittlement degree evaluated by semi-nondestructive SP test.

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Conservation Treatment and Deterioration Evaluation of the Namwon Singyeri Maaeyeoraejwasang (Rock-Carved Seated Buddha Statue), Korea (남원 신계리 마애여래좌상의 손상도 평가 및 보존처리)

  • Chun, Yu Gun;Lee, Myeong Seong;Lee, Jae Man;Lee, Jae Jin
    • Journal of Conservation Science
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    • v.29 no.4
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    • pp.321-332
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    • 2013
  • Namwon Singyeri Maaeyeoraejwasang (Rock-Carved Seated Buddha Statue) is composed mainly foliated granite and is different metamorphic grade and weathering degree on rock location. As the results of deterioration evaluation, upper part of the buddha statue was estimated that granularity decomposition was serious and rock strength was lower than lower part. Furthermore organism assessed most effect of among weathering factors. Chl. a amount of organism species were calculated $0.2{\mu}g/cm^2$ of crustaceous lichen, $1.1{\mu}g/cm^2$ of foliose lichen, $2.3{\mu}g/cm^2$ of bryophyte. Organism was taken treatment in order of amount of Chl. a and pre-cleaning, dry cleaning, wet cleaning in sequence. It should be establish conservation plan that strengthening in consideration of lithology characteristics and setting in good condition environment to conserve long-term of Maaeyeoraejwasang.

Environment Corresponding Package by Quantitative Mixing System with Functional Inorganic Material and Polyolefin Resin (기능성 무기물과 폴리올레핀계 수지의 정량적 혼합시스템에 의한 환경대응형 포장소재 개발)

  • Kim, Hi-Sam;Lim, Hyun-Ju;Park, Young-Mi
    • Textile Coloration and Finishing
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    • v.21 no.1
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    • pp.1-9
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    • 2009
  • A lot of research has been made over the recent decade to develop testing packages with antimicrobial properties to improve food safety. In this study, a new method, experimental device and technology for environmental corresponding packages of polypropylene (PP) film has been developed to provide effective temperature buffering during the transport/long-term storage of grains or foodstuffs from the supplier to the market. This quantitatively optimized mixing system enabled to produce PP films with the 700$\sim$1,400d (width;1.5$\sim$3mm, thickness;0.01$\sim$0.5mm). In the whole mixing systems, the finely-granulated inorganic illite and PP virgin chip for master batch (M/B) chip was calculated by digital measurement methods, and then the M/B chip for PP film was adapted through a air jet and PP grinding method. The prepared PP film was characterized with tensile strength and elongation, far infrared radiation (FIR) emissivity, antimicrobial activity and deodorization properties. The results revealed that the two differently grain-sized illite could be show homogeneously dispersed on PP chip surface, and as the increasing of illite content, the FIR emissivity and the anion emission rate of film was increasingly improved. In both of 325 and 1,500 mesh-sized illite contained PP chip, of course the antimicrobial activity was good. But the ultimate deodorization rate for ammonia gas of PP film were found to be approximately the same.

Effects of Cooling Method Followed by Casting on the Interfacial and Mechanical Properties of Dental CP-Ti Casts (치과용 티타늄 주조체의 냉각방법이 표면반응층 및 기계적 특성에 미치는 영향)

  • Moon, Soo;Jung, Jun-Young;Kim, Ki-Ju;Lee, Jin-Hyung
    • Journal of Biomedical Engineering Research
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    • v.24 no.5
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    • pp.375-380
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    • 2003
  • In this study. we have intended to control the properties of surface reaction zone generated between pure titanium and oxide investment moulds. Commercially pure titanium was centrifugally casted and silica$.$alumina based phosphate bonded investment was used as the mould material. The effect of cooling methods after casting on the surface reaction zone and mechanical properties of casts were investigated. The resulting casts showed the multilayered surface reaction zone regardless of cooling method. Especially. water cooling method produced the titanium casts with thinner surface reaction zone. weaker strength. and higher elongation properties compared to air cooling. It can thus be known that the resulting casts had satisfactory mechanical properties as dental materials. From these results, the cooling rate dependence of interfacial and mechanical properties can be attributed to the diffusion of oxygen from casting environment, which control the reaction of titanium and mould.