• 한국자기공명학회논문지
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• 제9권2호
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• pp.103-109
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• 2005

New PVC plasticizer, 2,2,4-trimethyl-1,3-pentanediol-1-butyrate-3-isobutyrate was synthesized via simple esterification with butyric acid and Texanol(a trademark of Eastman Chemicals), the mixture of 2,2,4-trimethyl-1,3-pentanediol-3-isobutyrate and 2,2,4-trimethyl-1,3-pentanediol-1-isobutyrate. The analysis of $^1H-1D,\;^{13}C-1D$ NMR and HMBC spectra identified internal-ester-transfer of 2,2,4-trimethyl-1,3-pentanediol-1-isobutyrate during the reaction. 2,2,4-trimethyl-1,3-pentanediol-1-butyrate-3-isobutyrate gave better properties in PVC than 2,2,4-trimethyl-1,3-pentanediol diisobutyrate(TXIB, a trademark of Eastman Chemicals) such as lower viscosity, higher tensile strength and better elongation. In particular, remarkably reduced migration compared with TXIB suggested a reduced emission of VOC(volatile organic compound) from PVC.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1675-1680
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• 2012

Three new cyanide-bridged $Cr^{III}Mn^{II}$ binuclear complexes, $[Mn(phen)_2Cl][Cr(bpmb)(CN)_2]{\cdot}H_2O$ ($\mathbf{1}$) (phen = 1,10-phenanthroline, $bpdmb^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate), $[Mn(phen)_2Cl][Cr(bpmb)-(CN)_2]{\cdot}H_2O$ ($\mathbf{2}$) ($bpdmb^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate), and $[Mn(phen)_2Cl]-[Cr(bpClb)(CN)_2]{\cdot}CH_3OH{\cdot}H_2O$ ($\mathbf{3}$) ($bpClb^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4-chloro-benzenate) were obtained based on $Mn(phen)_2Cl_2$ and a series of dicyanidechromate(III) building blocks. Single crystal X-ray diffraction analysis shows the structures of the three complexes are dimeric type with two different metal centers linked by a cyanide group from corresponding dicyanidechromate(III) building block. Magnetic investigations indicate the existence of relatively weak antiferromagnetic coupling between Cr(III) and Mn(II) ions with best-fit constants $J_{CrMn}=-2.78(5)cm^{-1}$ for $\mathbf{1}$, $J_{CrMn}=-3.02(2)cm^{-1}$ for $\mathbf{2}$ and $J_{CrMn}=-2.27(3)cm^{-1}$ for $\mathbf{3}$ based on the spin exchange Hamiltonian = $-2J_{CrMn}\hat{S}_{Cr}\hat{S}_{Mn}$. The magneto-structural correlation of cyanide-bridged $Cr^{III}Mn^{II}$ complexes has been discussed at last.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3615-3620
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• 2013

Two novel copper(II) bromide complexes with pyridine containing Schiff base ligands, $Cu(pmed)Br_2$ and $Cu(pmed)Br_2$ where pmed = N'-((pyridin-2-yl)methylene)ethane-1,2-diamine (pmed) and dpmed = N,N-diethyl-N'-((pyridin-2-yl)methylene)ethane-1,2-diamine (dpmed) were synthesized and characterized using X-ray single crystal structure analysis, optical and magnetic susceptibility measurements. Crystal structural analysis of $Cu(pmed)Br_2$ showed that the copper(II) ion has a distorted square-pyramidal geometry with the trigonality index of ${\tau}=0.35$ and two intermolecular hydrogen bonds, which result in the formation of two dimensional networks in the ab plane. On the other hand, $Cu(pmed)Br_2$ displayed a near square-pyramidal geometry with the value of ${\tau}=0.06$. In both compounds, the NNN Schiff base and one Br atom occupy the basal plane, whereas the fifth apical position is occupied by the other Br atom at a greater Cu-Br apical distance. The reported complexes show $g_{\mid}$ > $g_{\perp}$ > 2.0023 with a $d_{x2-y2}$ ground state and a penta-coordinated square pyramidal geometry. Variable temperature magnetic susceptibility measurements showed that the developed copper(II) complexes follow the Curie-Weiss law, that is there are no magnetic interactions between the copper(II) ions since the Cu--Cu distance is too far for magnetic contact.

• 상하수도학회지
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• 제36권5호
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• pp.261-273
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• 2022

In this study, we collect water control valves that have had accidents due to existing cracks, etc. are collected, and propose investigation items for strengthening the valve structural safety evaluation through a series of analyzes from valve specifications to physicochemical properties are proposed. The results of this study are as follows. First, there was a large variation in the thickness of the body or flange of the valves to be investigated, which is considered to be very important factor, because it may affect the safety of the valve body against internal pressure and the flange connected with the bolt nut. Second, 60% of the valves under investigation had many voids in the valve body and flange, etc. and the decrease in thickness due to corrosion was relatively large on the inner surface in contact with water rather than the outer surface. It is judged that the investigation of depth included voids is very important factor. Third, all valves to be investigated are made of gray cast iron foam, and therefore it is judged that there is no major problem in chemical composition. It is judged that the chemical composition should be investigated. Fourth, as a physical investigation item, the analysis of metal morphology structure seems to be a very important factor for nodular cast iron from rather than a gray cast iron foam water valve with a flake structure. As it was found to be 46.7~68.8% of the standard recommended by KS, it could have a direct effect on damage such as cracks, and therefore it is judged that the evaluation of tensile strength is very important in evaluating the safety of the valve.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.245-245
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• 2006

Recent studies of single wall carbon nanotube (SWNT)/polyimide nanocomposites indicate that these materials have a potential to provide the combination of structural integrity and sensing/actuation capability. This study shows the effect of the SWNT type and concentration on the dipole orientation and piezoelectric properties of the electroactive polymide nanocomposites using a thermally stimulated current (TSC) spectroscopy. These nanocomposites exhibit very thermally stable piezoelectric properties up to $150^{\circ}C$. This presentation will highlight the dipole orientation and electroactive characteristics of the SWNT/polyimide nanocomposites and discuss their potential multifunctional aerospace applications.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2009년 추계학술발표대회
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• pp.51-51
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• 2009

In order to understand the properties of high heat input welds made by electro gas welding, two kinds of low temperature steel were welded. Welding heat inputs were controlled by width of root gap and ranged from 118 to 143kJ/cm. Chemical composition and micro-structural analysis were performed. To understand low temperature impact properties, Charpy impact test was conducted at several temperatures. The results were summarized as follows; 1) Grain size of weld metal and heat affected zone was increased with an increase in welding heat input. 2) Impact test values at fusion line were severely fluctuated regardless of base metals, showing enormous difference among the values at the same test temperature.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.209-209
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• 2000

Carbon nanotubes have been intensively investigated for its fundamental and technical importances. Structural diversities and the related diverse physical properties with large aspect ratios are fascinating, For instance carbon nanotubes are metal and semiconductors depending on its chirality and furthermore the band gap can be tailored by the diamters. Several issues on its fundamental properties have been discussed. We will review some fundamental problems for band structures, molecular quantum wires, homojunctions, single electron tunneling, and quantum conductance. Several issues related to syntheis of carbon nanotubes including arc discharge, chemical vapor deposition, laser ablation will be extentively discussed. We will further review the applicability of carbon nanotubes on resonator, nanobalance, FET-type transistor, field emission displays electrode for secondary battery and hydrogen storage.

• Structural Engineering and Mechanics
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• 제86권2호
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• pp.211-220
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• 2023

The textile industry has benefited from nanotechnology in various fields of application as the use of nanomaterials, and nanotechnology is multiplying. Nanoparticles can increase the performance of textiles by up to 100 times when used in finishing, coating, and dyeing techniques, providing them with capabilities they did not previously possess. Nanotechnology is used in the textile chemical industry to produce sports mats with stain resistance, flame resistance, wrinkle resistance, moisture management, antimicrobial quality, and UV protection. The incorporation of nanomaterials into fabrics can have a significant effect on their properties, including shrinkage, strength, electrical conductivity, and flammability. Various inventions and innovations may result from nano-processed textiles in the future, thus leading to the advancement of science. This article presents the construction of sports engineering structures with high resistance to improve the quality of sports training. The mechanical properties of sports mats are improved with the help of nanotechnology. Strength, elasticity, and tear resistance are among these properties. This method enables the production of elastic, durable, and tear-resistant sports mats.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.318.2-318.2
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• 2016

FeM2X4 spinel structures, where M is a transition metal and X is oxygen or sulfur, are candidate materials for spin filters, one of the key devices in spintronics. Both the Fe and M ions can occupy tetrahedral and octahedral sites; therefore, these types of compounds can display various physical and chemical properties [1]. On the other hand, the electronic and magnetic properties of these spinel structures could be modified via the control of cation distribution [2, 3]. Among the spinel oxides, iron manganese oxide is one of promising materials for applications. FeMn2O4 shows inverse spinel structure above 390 K and ferrimagnetic properties below the temperature [4]. In this work, we report on the structural and magnetic properties of epitaxial FeMn2O4 thin film on MgO(100) substrate. The reflection high energy electron diffraction (RHEED) and X-ray diffraction (XRD) results indicated that films were epitaxially grown on MgO(100) without the impurity phases. The valance states of Fe and Mn in the FeMn2O4 film were carried out using x-ray photoelectron spectrometer (XPS). The magnetic properties were measured by vibrating sample magnetometer (VSM), indicating that the samples are ferromagnetic at room temperature. The structural detail and origin of magnetic ordering in FeMn2O4 will be discussed.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2010년도 춘계학술 발표회
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• pp.91-91
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• 2010