• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.35-41
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• 1999

Friction and wear test was performed for nylon, acetal resin, and PTFE(polytetrafluoroethylene) under reciprocating dry sliding conditions against a steel counterpart. Friction coefficient and specific wear rate were analysed as a function of sliding distance and applied load. The worn surfaces of plate and disc specimens were observed using SEM(Scanning Electron Microscopy). The experimental results show that acetal resin exhibited lowest wear rates whereas PTFE possessed lowest friction coefficient. The prominent wear mechanisms found were adhesion and abrasion.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1401-1404
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• 2007

An efficient Pictet-Spengler type reaction of N,O-acetal TMS ethers for the practical synthesis of 1-substituted tetrahydroquinolines, medicinally important alkaloids, has been accomplished. To demonstrate the versatility of this novel procedure, the total synthesis of calycotomine, a representative 1-hydroxymethyl substituted tetrahydroisoquinoline, is also described.

• Korean Journal of Pharmacognosy
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• v.25 no.4 s.99
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• pp.307-310
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• 1994

A hitherto unknown substance was isolated from the commercial sample of Aloe arborescens, which was shown to be the 4',6'-O-ethylidene-aloenin, most likely an artifact caused by hot-air drying procedure for the product preparation.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.253-255
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• 2001

기능성고분자재료 중의 하나인 7원환 고리아세탈 화합물인 1,3-dioxepan-2-one(1)을 합성하고 고온조건 하에서 중합반응을 조사한 결과 선택적인 개환중합이 일어났다. 그러나 낮은 농도에서 작은 분자량을 가지는 고분자가 얻어졌으며 넓은 분자량 분포와 낮은 수율이 얻어지며 이것은 중압반응 도중에 분자 내에서 상호반응을 일으킴을 보여준다.

• Tribology and Lubricants
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• v.16 no.5
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• pp.324-331
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• 2000

Wear characteristics of Plastic and Nylon pinions against steel gear were studied to gain a better understanding of their tribological behaviors. Wear tests were conducted with power circulating gear test rig under dry contact conditions. Specific wear rates were measured as a function of applied load and the number of revolution. The worn teeth surfaces were examined with a profile projector and a camera. Nylon pinion showed lower specific wear rates than acetal pinion, but suffered teeth breakage under high load per unit tooth width. The dominant wear mechanisms found were adhesion and abrasion.

• Bulletin of the Korean Chemical Society
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• v.17 no.11
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• pp.980-981
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• 1996

• Bulletin of the Korean Chemical Society
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• v.16 no.10
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• pp.1003-1006
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• 1995

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.373-375
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• 1999

• Bulletin of the Korean Chemical Society
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• v.17 no.8
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• pp.674-676
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• 1996

• Journal of the Korean Applied Science and Technology
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• v.5 no.1
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• pp.53-62
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• 1988

Properties of aqueous solution, that is, the viscosities and solubilities of benzene were observed in relation to critical micelle concentration of each alkyl aldehyde polyoxyethylene glycol acetal type surfactant. These showed that the mininum points in specific viscosity/concentration-concentration curves were corresponded with the critical micelle concentration obtained by surface tension and appeared the remarkable increase of non-Newtonics according to the increase of the number of carbon in hydrophobic groups. The fluidity of non-Newtonics is not observed by a little increase of the degree of polymerization in polyoxyethylene glycol groups.