• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.9 no.2
• /
• pp.93-103
• /
• 1980

A small domestic solar water heating system in thermosyphonic flow was tested in Seoul. The system consisted of four flat plate aluminium roll bond type collectors of total effective area $3.28m^2$ and a $280{\iota}$ storage tank. It was tilted $52^{\circ}$ relative to the horizon. And the collector plate, collector tube and storage tank were equiped with 14 thermocouples. As the results, the following facts were found; 1) To provide water at $55^{\circ}C$ for a family of four in Seoul, a collector area of $3-4m^2$ and a storage capacity of $180{\iota}- 200{\iota}$ are suggested. And this system can supply hot water at above $45^{\circ}C$ day about. 2) In the late afternoon hours, it might be advantageous to stop the flow in the system as heat losses to the environment increase unduly. 3) Without any hot water consumption throughout the day, water temperature distributions inside the storage tank was found almost linear. This indicates essentially no mixing inside the storage tank. 4) In case of a small domestic solar water heating system, it is better to employ a single transparent cover rather than double one.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.55-60
• /
• 2001

Influencing factors on flexural toughness of ring-type fiber reinforced concrete(RSFRC) are investigated. An experiment proceeding ASTM C 78 is peformed to make a comparison between ring-type fibers and double-hook type fibers. Most specimen with ring type fibers have failed by the cone type failure, while discrete hook type fibers have failed by fiber pullout. For the hook-type fiber reinforced concrete(SFRC), the first crack load increases, as the fiber mixing volume increases. Aspect ratio(fiber length/fiber diameter) is critical for hook type fibers, so the flexural toughness increases significantly, as the length of fiber increases. However, for the ring type, the toughness indices Increase as the number of fibers in the specimen increases. Since there is no bond problem between the ring fiber and the concrete matrix, the aspect ratio does not affect the performance of the composite material with the newly developed steel fibers. Influencing factors with respect to flexural toughness RSFRC were observed to be ring diameter, diameter of steel fiber and fiber content.

• Journal of the Korean Applied Science and Technology
• /
• v.9 no.2
• /
• pp.119-126
• /
• 1992

The kinetics of the hydrolysis of indolylacrylophenone derivatives(IA) was investigated by ultraviolet spectrophotometry in 30% dioxane-$H_2O$ at 25$^{\circ}C$ Rate equations were obtained over a wide pH range. On the basis of rate equation, general base catalysis and Hammett's plot, the mechanism of hydrolysis to the (IA) were proposed: Below pH 3.0, the hydrolysis of (IA) was proportional to hydronium ion concentration, between pH 4.0${\sim}$9.0 neutral water molecule and hydroxide ion were added to carbon-carbon double bond and over pH 10.0 hydrolysis of (IA) was proportional to hydroxide ion concentration.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.772-775
• /
• 2006

Cinnamate polymers are well known photoreactive polymers due to [2+2] cycloaddition reaction of cinnamate side group. In this work, we have found that the cinnamate side groups could be also reacted by thermal energy, and this reaction is presumed to attribute to the radical reaction of carbon double bond in the cinnamate groups. Contrary to the photocycloaddition reaction of the cinnamate side groups, the thermal reaction of cinnamate side group was closely related to the flexibility of polymer backbone. The difference of the mechanism between the photocycloaddition reaction and thermal crosslinking reaction was confirmed by $^1H-NMR$$ and $^{13}C-NMR$ analysis of the model compound.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.297-298
• /
• 2011

Metal/poly (4,4'-aminotriphen-ylene hexafluoroisopropylidenediphthalimide) (TP6F PI)/metal structure exhibited an electrically volatile phase transition with high (OFF) or low (ON) resistive states when voltage between electrodes swept. Here, we demonstrate a noble set-up in which holes are injected by photoelectron emission process during the voltage sweep instead of direct charge carrier injection via metal electrode, which enables direct investigation into changed electronic structures of TP6F PI both in ON and OFF states using photoemission spectroscopy methods. In the I-V measurement, TP6F PI shows a non-volatile behavior. In spectroscopic results, this non-volatile behavior is leaded from the structural modification of the O=C double bond in phthalimide of TP6F PI by hole injection.

• Journal of the Korean Chemical Society
• /
• v.20 no.6
• /
• pp.507-513
• /
• 1976

Conformation of cis-2-butenedialdioxime, a newly synthesized compound, was assigned by means of nuclearmagnetic resonance, extended Huckel molecular orbital method, and Pople's model of anisotropic effect. It was confirmed that two carbon-carbon single bonds are conrotatorily twisted from the molecular plane of six $sp^2$ orbitals of carbon-carbon double bond. The conformation of minimum energy is found to be twisted by$25^{\circ}C.$

• Archives of Pharmacal Research
• /
• v.24 no.4
• /
• pp.300-306
• /
• 2001

A novel and two known bioactive mono-tetrahydrofuran (THF) annonaceous acetogenins, annomocherin (1), annonacin (2) and annomontacin (3), have been isolated from the fractionated ethanolic extracts of the seeds of Annona cherimolia, guided by the brine shrimp lethality test (BST). Their structures were elucidated on the basis of spectroscopic and chemical methods. All compounds have a relative stereochemistry of threo/trans/threo for the mono-THF ring with two flanking hydroxyls. Compound 1 has a double bond at C-23/ 24 of aliphatic chain. Compound 1 was isolated from natural sources for the first time, and was named annomocherin. Two known Compounds 2 and 3 which have never been isolated from this species before, were obtained. Compound 1 exhibited potent and selective cytotoxicities against the breast carcinoma (MCF-7) and kidney carcinoma (A-498) cell lines with 100 to 1,000 times the potency of adriamycin. In brine shrimp lethality test (BST), 1-3 exhibited cytotoxicity.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.1
• /
• pp.66-70
• /
• 1997

The polymerization of 4, 4-bis(acetoxymethyl)-1, 6-heptadiyne (BAH) was carried out by MoCl5 and WCl6 with various organometallic cocatalysts. MoCl5-based catalysts were more effective than WCl6-based ones for the cyclopolymerization of BAH. Poly(BAH) was characterized to have polymer backbone with conjugated double bond and cyclic structure by IR, UV-visible, and 1H-and 13C NMR spectroscopies. The polymer was stable up to 310 ℃ and 5 % weight loss show up at 350 ℃. The resulting dark violet polymer exhibited good solubility in common organic solvents and could be cast on a glass plate to give film with good mechanical properties. It was found that oxygen permeability (PO2) and permselectivity (PO2/PN2) of the resulting polymer were 15.2 barrer and 2.84, respectively.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1995.04a
• /
• pp.60-60
• /
• 1995

새로운 혈소판 활성화인자 (PAF) 수용체 결합 저해활성 유효성분인 pinusolide ($IC_{50}$/=2.5$\times$$10^{-7}$M)와 arctigenin($IC_{50}$/=5.2$\times$$10^{-6}$M)을 측백엽(Biota orientalis)과 우방자(Arctium lappa)로부터 분리하여 이미 보고한 바 있다. PAF 수용체에 대한 구조활성 상관관계를 규명하고자 또한 용해도가 우수한 강력한 PAF 길항제를 개발하고자 이 길항제들의 유도체들을 다양한 유기화학반응을 이용하여 합성하였고 in vitro PAF receptor binding assay로 그 활성의 강도를 비교 검토하였다. 그 결과, lactone ring 부분은 unsaturated lactone이 saturated lactone보다 활성이 강하였고 ring이 개열되면 활성이 현저히 감소하였다. pinusolide 경우 exocylclic double bond 부분은 sp$^2$구조의 hydrophobic한 유도체가 활성이 강하였으며, methyl ester 부분은 hydrophobic한 유도체가 활성이 강하였다. Arctigenin의 경우 aromatic unit가 hydrophobic할수록 활성이 강하였다.

• Journal of the Korean Applied Science and Technology
• /
• v.22 no.4
• /
• pp.323-331
• /
• 2005

Fatty acid compositions of the seed oils of P. schinseng, A. continentalis and A. sessiliflorus, were analyzed by gas chromatography (GC) equipped with a capillary column. A large unusual peak was observed just before the peak corresponding to oleic acid $(cis-9-C_{18:1})$. This unknown fatty acid was isolated by silver ion chromatography and then derivatized into the picolinyl ester. The mass spectrum of the picolinyl ester showed molecular ion at m/z=373 with other diagnostic ions such as m/z=178, 218, 232, 246, 274, 288, 302 and 344. Characteristic absorption peaks at $720\;cm^{-1}$, $1640\;cm^{-1}$ and $3010\;cm^{-1}$ in IR spectrum indicated the presence of cis-configurational double bond in the molecule. The $^1H-NMR$ spectrum of this acid gave two quintets centered at ${\delta}1.638$ (2H, C-3) and ${\delta}1.377$ (2H, C-4), and two multiplets centered at ${\delta}2.022{\sim}2.047$ (2H, C-5) and ${\delta}2.000{\sim}2.022$ (2H, C-8), and multiplet signals of olefinic protons centered at ${\delta}5.3015{\sim}5.3426$ (C-6, J=9.5 Hz) and ${\delta}\;5.3465{\sim}5.3877$ (C-7, J=9.5 Hz). The $^13C-NMR$ spectrum showed 18 carbon resonance signals including an overlapped signal at ${\delta}29.7002$ for C-12 and ${\delta}29.6520$ for C-13 (or they can be reversed), and other highly resolved signals at ${\delta}33.950$, ${\delta}24.558$, ${\delta}26.773$ and ${\delta}27.205$ due to C-2, C-3, C-5 and C-8 of a ${\Delta}^6-octadecenoic$ acid, respectively. From analysis results this unknown fatty acid could be identified as cis-6-octadecenoic acid. The seed oils of P. schinseng and A. sessiliflorus contained petroselinic acid (59.7%, 56.0%), oleic acid (18.3%, 6.1%) and linoleic acid (16.2%, 30.4%) with small amount of palmitic acid (3.0%, 3.1%) while the seed oil of A. continentalis comprised mainly oleic acid (30.2%), petroselinic acid (29.0%), linoleic acid (24.1%) and palmitic acid (13.1%).