• 월간 기계설비
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• s.240
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• pp.48-49
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• 2010

지식경제부 기술표준원이 수도관, 오 배수관, 토목용 하수관으로 광범위하게 사용되는 PVC(폴리염화비닐)관의 품질과 위생기준을 강화해 지난 해 7월 1일부터 납 안정제와 가소제 등의 사용을 금지하고, 위생성 및 장기내구성 등의 품질기준이 강화된 흰색 PVC관을 상 하수도관으로 사용토록 했으나 아직도 이를 제조하거나 시공하고 있어 주의를 촉구하고 나섰다. 이에 따라 PVC관을 수도관, 오 배수관으로 시공하고 있는 설비건설업계의 주의가 요망된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4223-4238
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• 2011

The advantages of grouting are the simple instrument, the simple procedure of practice and the simple verification of grouting result. but the more grouting practice there is, the more damages of environment from grouting practice and grouting materials there are. so, the grouting materials and methods with the character of environment friendly are introduced in construction field, recently. This paper is to study of the physical characteristics that has thixotropic character and that consists of inorganic and polycarboxylate co-polymer. In study, various testing methods are performed such as a viscosity, a thixotropy, a compressive strength, a heavy metal detection and pH measurement in lab test and a low pressure injection test and a high pressure injection test in field with different soil type. As a result, a optimum mix ratio is proposed by analyzing the result of lab test. the field applicability is verified by checking a injection pressure, a grout volume and a hardened body of grout by excavating the practice site.

• Elastomers and Composites
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• v.38 no.4
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• pp.342-353
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• 2003

This work is about the development of jet-fuel resistant PVC sealant using a polyester plasticizer. PVC copolymer was compounded with adipic acid glycol(Songcizer P-3000) or DOP plasticizers. Fuel-immersed and non-immersed penetration, solubility, flow, and elongation by tensile adhesion of PVC compounds were measured. Penetration increase by fuel immersion and solubility of PVC compounds with adipic acid glycol polyester plasticizer were smaller than those of PVC compounds with DOP plasticizer. Elongation by tensile adhesion test of PVC compound containing 500 phr of Songcizer P-3000 decreased proportionally to the content of DCDP (dicyclopentadiene) base petroleum resin adhesion promoter. Calcium carbonate($CaCO_3$) filler inhibited the diffusion of fuel in all the PVC compounds and decreased the solubility of PVC compounds containing Songcizer P-3000.

• Polymer(Korea)
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• v.30 no.3
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• pp.202-206
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• 2006

The plasticized cellulose diacetate (CDA) was prepared by melt processing methods using triacetine (TA) as a plasticizer. Additionally, processability of CDA was enhanced by using epoxidized soybean oil as a secondary plasticizer. The glass transition temperature of plasticized CDA was observed at $50^{\circ}C$ lower than virgin CDA and the incorporation of 5% ESO also resulted in the additional $20^{\circ}C$ decrease in the $T_g$. The tensile properties and modulus of plasticized CDA were better than commercial PP and PLA. The aerobic biodegradability of CDA in controlled compositing condition resulted in 90% of degradation during 60 days.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.6
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• pp.32-38
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• 2017

Plasticizers play roles in increasing plasticity or fluidity during mixing. Representative plasticizers are DOS, DOA, IDP and BTTN. In particular, BTTN is an energy plasticizer that helps propellant performance and is widely used. However these compounds are sensitive relatively. So, in order to develop insensitive energetic plasticizer, synthesis of one of the derivatives of triazole, 4,5-bis (azido methyl)-(1-butyl)-1,2,3-triazole (1-DABTR), was studied. Also, the compound was characterized by NMR, IR spectroscopy, and physicochemical properties such as glass transition temperature, melting point, decomposition temperature, density, viscosity and impact sensitivity were measured. In addition, the heats of formation (${\Delta}H_f$) of 1-DABTR was also calculated using Gaussian 09.

• Polymer(Korea)
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• v.26 no.6
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• pp.778-784
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• 2002

Chemical modification of a dextran film to improve its physical properties was carried out by addition of plasticizers and crosslinking agents. Moreover, low-temperature plasma treatment with acetylene gas was done. The dextran film showed high mechanical strength but was brittle and vulnerable to moisture. When plasticizer was added, it became very soft but with large reduction of mechanical strength. However, a flexible film with fairly high mechanical strength and water resistance was prepared when the film was crosslinked by adding crosslinking agent with or after the addition of plasticizer. Treatment with an acetylene plasma changed the dextran film surface from hydrophilic to hydrophobic with little influence on the bulk properties of the film.

• Elastomers and Composites
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• v.13 no.3
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• pp.240-244
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• 1978

• Explosives and Blasting
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• v.34 no.4
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• pp.1-9
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• 2016

For underwater steel structure, cut that underwater shaped charge device that combines a spring hose, which is an external device of pressure resistance and flexibility with flexible shaped charge, was invented. As a basic experiment for an optimum condition design, an penetration performance was compared by external device shape. To evaluate the result of an experiment, image analysis was carried out after obtaining the model by using the liquid rubber for the penetrated steel plate. To simulate the penetrating process of shaped charge, the AUTODYN program has been used. As a result of analysis, while the average penetration depth of circular and square shaped external devices were similar, the penetration quality was more uniform in the case of circle. In addition, water infiltration occurred in square case, displacement and strain rate according to the increase of the water pressure were measured high.

• Science of Emotion and Sensibility
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• v.24 no.2
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• pp.39-48
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• 2021

According to International Associating for the Study of Pain (IASP) definition, neuropathic pain is a disorder characterized by dysfunction of the nervous system that, under normal conditions, mediates virulent information to the central nervous system (CNS). This pain can be divided into a disease with provable lesions in the peripheral or central nervous system and states with an incorporeal lesion of any nerves. Both conditions undergo long-term and chronic processes of change, which can eventually develop into chronic pain syndrome, that is, nervous system is inappropriately adapted and difficult to heal. However, the treatment of neuropathic pain itself is incurable from diagnosis to treatment process, and there is still a lack of notable solutions. Recently, several studies have observed the responses of CNS to harmful stimuli using image analysis technologies, such as functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and optical imaging. These techniques have confirmed that the change in synaptic-plasticity was generated in brain regions which perceive and handle pain information. Furthermore, these techniques helped in understanding the interaction of learning mechanisms and chronic pain, including neuropathic pain. The study aims to describe recent findings that revealed the mechanisms of pathological pain and the structural and functional changes in the brain. Reflecting on the definition of chronic pain and inspecting the latest reports will help develop approaches to alleviate pain.

• Journal of Korea Foresty Energy
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• v.17 no.1
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• pp.36-46
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• 1998

The aim of this study was to develop the noise and vibration damping wood-based composites by using viscoelastic polymer materials. Polyvinylchloride(PVC) was plasticized with 20-140 phr bis(2-ethylhexyl) phthalate(DOP) and the dynamic tensile mechanical properties were measured at 110Hz and approximate temperature range -100 to 150$^{\circ}$ using a Rheovibron Instrument. The PVC/DOP blends were shown to be compatible in all proportions, and both T(E”$_{max}$) and T(tan${\delta}_{max}$) shifted to the lower temperature side as the DOP content increased. The vibration damping properties of wood/polymer composites were measured using the Rheovibron instrument in a bending mode. The composite damping factor(tan ${\delta}_{c}$) of wood /PVC-DOP/wood sandwich structure correlated with the loss factor and that of the coated structure correlated with the loss modulus(E”) of the polymer layer. In addition, the sandwich structure was found to be more effective in damping than the coated structure. The logarithmic decrement (${\Delta}$c) curve of a sandwich structure, which was determined by the free-free flexural vibration method was similar in shape to the tan ${\delta}_{c}$ curve.