• Restorative Dentistry and Endodontics
• /
• 제17권1호
• /
• pp.22-35
• /
• 1992

The aim of this study was to investigate the effect of herbal organic extracts on the pain response provoked by noxious stimuli on dental nerve and the peripheral nerve conduction. Cats (2-2.5Kg regardless of sex) that were chosen as experimental animals were classified into control group, Asiasari radix application group and Zingiberis rhizoma application group. They were anesthetized with ${\alpha}$-chloralose, then anterior belly of digastric muscle of both sides were exposed and wire electrodes were inserted for recording of Electromyogram (EMG). Cavities were prepared on canines until pulp of the teeth were exposed. And after the drugs solubilized for 2% and 4% concentration (W/V) in vehicle were applied, their effects were compared through the recording of EMG immediately after drug application, 30 minutes, 60 minutes, 120 minutes and 5 days after, respectively. And after both inferior alveolar nerves were exposed, 4% organic extracts of Zingiberis rhizoma and Asiasari radix were applied for 30 minutes then the change of jaw opening reflex provoked by noxious stimuli on pulpal nerves were observed immediately after washing out, at 30, 60 and 90 minutes after drug had been washed out. After saphenous nerve of both sides were exposed, one side of nerve was used for vehicle application and the other side was used for drug application for 30 minutes. Then conduction of action potential of A-${\delta}$ and C-fiders of saphenous nerves, which have changed with time, was recorded. With analysis of these records, the following results were obtained: 1. Organic extract of Zingiberis rhizoma (2% or 4% concentration) greatly suppressed EMG of digastric muscle provoked by noxious stimuli on pulpal nerve at five days after application, the suppressive: effect was greater than that of organic extract of Asiasari radix. 2. Organic extract of Asiasari radix (2% or 4% concentration) suppressed jaw opening reflex provoked by noxious stimuli on pulpal nerve, at 5 days after drug application. 3. Organic extract of Zingiberis rhizoma and Asiasari radix (immediately after 30 minutes application) suppressed neural conduction of A-${\delta}$ and C-fibers, the suppressive effect was greater on A-${\delta}$ fibers than on C-fibers. 4. Jaw opening reflex provoked by noxious stimuli on pulpal nerve in inferior alveolar nerve was greatly suppressed 30 minutes after drug application, this effect was greater by Zingiberis rhizoma than by Asiasari radix.

• 한국주조공학회지
• /
• 제42권4호
• /
• pp.218-225
• /
• 2022

본 연구에서는 고압 다이캐스팅 (High pressure die-casting, HPDC)을 통해 알루미늄 합금 (상업코드: ALDC12종)으로 수소 자동차용 부품 (Air pressure control valve housing, APCVH)을 제조하였으며 주조품의 기밀성을 향상시키기 위해 유기 함침액을 개발하였다. 개발된 2종류의 유기 함침액 (INNO-series, 한국)과 상용 합침액 (P601, 일본)을 사용하여 함침공정 조건 및 후 처리에 따른 미세결함과 기밀성을 비교 평가하였다. 컴퓨터 단층촬영 및 3차원 X-선 현미경 분석을 통해 함침된 알루미늄 주조품의 결함제어 및 성능 개선을 확인하였다. 또한, 함침 공정 후 기밀성 시험에서 INNO-01이 함침된 시료의 경우 성능 개선율이 70%인 것으로 확인하였다. 따라서, 개발된 유기 함침액은 상용 가능하며 다이캐스팅 제품의 기밀성 향상에 도움이 될 것으로 판단된다.

• 에너지공학
• /
• 제21권4호
• /
• pp.398-401
• /
• 2012

본 연구에서는 자동차용 엔진 폐열 회수 유기랭킨사이클에 적용하기 위해 개발 중인 스크롤 팽창기의 효율을 상용 스크롤 팽창기와 비교 분석을 수행하였다. 팽창기 효율 특성 시험을 위해 유기랭킨사이클을 운전하면서 팽창기 출력, 팽창기 입구 온도, 압력 및 작동유체(냉매 R134a)의 유량을 측정하였으며, 개발 중인 스크롤 팽창기의 전효율은 상용 스크롤 팽창기의 전효율에 비해 매우 낮은 수준을 나타내었다. 특히 팽창기 내부의 작동유체 누설에 의한 체적효율 저하가 전효율 저하에 큰 영향을 주는 것으로 파악되었기 때문에 향후 팽창기 효율 향상을 위해 팽창기 내부의 누설문제를 필히 해결해야할 것으로 분석되었다.

• 대한방사성의약품학회지
• /
• 제6권2호
• /
• pp.171-176
• /
• 2020

Covalent organic frameworks (COFs) are porous crystalline polymers in which organic units are linked by covalent bonds and have a regular arrangement at the atomic level. Recently, the COFs have been much attention in bio-medical area such as bio-imaging, drug delivery, and therapeutics. These 2D nanoparticles are proving their value in nanomedicine due to their large surface area, functionalization through functional groups exposed on the surface, chemical stability due to covalent bonding, and high biocompatibility. The high ω-electron density and crystallinity of COFs makes it a promising candidate for bioimaging probes, and its porosity and large surface area make it possible to be utilized as a drug delivery vehicle. However, the low dispersibility in water, the cytotoxicity problems of COFs are still challenged to be solved in the future. In this regard, several efforts that increase the degree of dispersion through functionalization on the surface of COFs for the application to the biomedical field have been reported. In this review, we would like to describe the advantages and limitations of COFs for bio-imaging and anti-cancer treatment.

• 한국군사과학기술학회지
• /
• 제3권2호
• /
• pp.53-60
• /
• 2000

Organic brake materials are installed in the braking system of korean model combat vehicles. Since the binder resin is decomposed in high temperature region, it may possible to drop the friction force which makes the vehicle stop within the desired distance. This study analyses the braking performance of the brake materials in high temperature region by using the pin-on-disk type friction tester. It is observed radical drop of friction coefficients and rapid increase of wear amounts from the transition temperature. It is due to the formation of oxide layer on the friction surface.

• 한국대기환경학회지
• /
• 제29권6호
• /
• pp.713-721
• /
• 2013

This study is about emission characteristics of HAPs and particulate matters emitted by spray of paint and organic solvent usually used in vehicle paint facilities. To analyze emission characteristics of HAPs and particulate matters emitted from vehicle paint facilities are calculated based on the measuring emission quantity of pollutants based on the amount of paint used (kg) and unit area ($m^2$) by paint manufacturers (J company, K company, and R company). In cases of paint manufacturers (J, K, and R), average emission factors of VOCs, carbonyl compound, particulate matter, and PAHs per 1 kg of paint were 327.81 g/kg, 5.98 g/kg, 336.70 g/kg, and 0.0078 g/kg respectively. The average emission factors of VOCs, carbonyl compounds, particulate matters, and PAHs by unit area were $171.55g/m^2$, $3.10g/m^2$, $176.27g/m^2$, and $0.0036g/m^2$ respectively.

• 감성과학
• /
• 제15권2호
• /
• pp.177-182
• /
• 2012

20세기의 자동차는 엔진의 주역할인 파워, 스피드를 중요시 하였으나, 소득수준의 향상에 따른 Well-being Trend의 확산 및 환경문제의 대두로 인해 쾌적성, 안락성, 안정성, 환경성 등을 중요시 하고 있다. 자동차용 Sub-Mat는 바닥 카펫 관리의 편의성 및 안락성 등을 위해 부가적으로 설치하는 매트로, 현재 자동차용 Sub Mat의 Backing 소재는 재생고무, PVC 등이 사용되고 있지만, 재생고무 Sub-Mat는 흡음성능이 나쁘고 PVC Backing Sub-Mat는 중량이 매우 커 연비 면에서 불리하고, 유해물질이 다량 포함되어 있어 점차적으로 사용이 어려워질 전망이다. 본 연구에서는 나일론 표피 파일 층, PE 접착 층, Backing(PET fiber)을 합포하여 제작한 sample1과 PET표피 파일 층, PE 접착층, Backing 부직포 층(PET)을 합포하여 제작한 sample2, Backing층을 PVC로 요철을 부여하여 제작한 sample3의 Non-Slip성을 평가하였으며, 이에 따른 접촉면의 변화를 비교 평가하였다.

• 한국대기환경학회지
• /
• 제26권3호
• /
• pp.318-329
• /
• 2010

The purpose of this study was to develop the $PM_{2.5}$ source profiles for diesel and gasoline-powered vehicles, which contained mass abundances in terms of mass fraction of $PM_{2.5}$ of chemical species. Seven diesel-powered vehicles and nine gasoline-powered vehicles were sampled from a chassis dynamometer exhaust dilution system. The species measured were water-soluble ions, elements, elemental carbon (EC), and organic carbon (OC). From this study, the large abundances of EC (54.5%), OC (26.0%), ${SO_4}^{2-}$ (1.5%), ${NO_3}^-$ (0.8%), and S (0.6%) were observed from the diesel-powered vehicle exhaust showing that carbons were dominant species. The gasoline-powered vehicle exhaust emitted large abundances of OC (38.3%), EC (4.2%), ${SO_4}^{2-}$ (3.6%), ${NH_4}^+$ (3.5%), and ${NO_3}^-$ (3.0%). The abundances of ${SO_4}^{2-}$, ${NH_4}^+$, and ${NO_3}^-$ from gasoline vehicle were greater than those of diesel vehicle. The emissions of P, S, Ca, Fe, and Zn among trace elements for the gasoline vehicle were greater than 1% of the $PM_{2.5}$ mass unlike those for the diesel vehicle. Particularly, the fraction of Zn was five times higher from the gasoline vehicle than that from the diesel vehicle. The source profiles developed in this work were intensively examined by applying chemical mass balance model.

• Environmental Engineering Research
• /
• 제14권3호
• /
• pp.180-185
• /
• 2009

Only limited information is available as regards to the exposure levels of naphthalene (polycyclic aromatic hydrocarbons, PAHs) and monocyclic aromatic hydrocarbons(MAHs) in the interiors of diesel-fueled passenger cars, while many studies investigated the exposure levels of various volatile organic compounds(VOCs) in the interiors of gasoline-fueled passenger cars or public buses. Present study was performed to supplement this deficiency by measuring naphthalene (as a representative of PAHs) and MAHs levels inside five diesel-fueled and five gasoline-fueled passenger cars while morning and evening commuting on real roadways. Each car was surveyed five times on different sampling days. The in-vehicle naphthalene levels were higher for the diesel-fueled cars as compared to gasoline-fueled cars, whereas the results were reversed for the in-vehicle MAH levels. The median cabin levels of diesel-fueled cars were 1.3, 7, 13, 4, and 6 ${\mu}g/m^3$ for naphthalene, benzene, toluene, ethyl benzene, and m,pxylene, respectively. With respect to gasoline-fueled cars, their respective levels were 0.7, 11, 21, 7, and 9 ${\mu}g/m^3$ . The median MAHs concentration ratios of gasoline-fueled cars to diesel-fueled cars ranged from 1.50 to 1.75, while the median naphthalene concentration ratio was estimated to be 0.54. In addition, there was no significant difference of both naphthalene and MAHs between the diesel-fueled cars, but the in-vehicle levels were significantly different between gasoline-fueled cars. The concentration levels of both naphthalene and MAHs were higher in the passenger cars than other non-industrial microenvironments. Consequently, it was confirmed that the cabins of both diesel-fueled and gasoline-fueled passenger cars are an important microenvironment associated with the exposure to naphthalene and MAHs.

• 한국대기환경학회지
• /
• 제24권3호
• /
• pp.275-283
• /
• 2008

Since mobile source is a major source of VOCs, quantifying emissions from motor vehicles is an important factor to control VOCs in atmosphere. In this study, in order to evaluate tailpipe VOCs emissions from motor vehicles, mass emissions of non-methane volatile organic compounds from 45 vehicles were determined. Measurements were made on a chassis dynamometer using CVS-75 mode and speed specific drive modes. Target VOCs are 53 compounds determined as the volatile ozone precursors. The individual VOCs composition of vehicle emission and emission rates were also determined. In case of gasoline vehicles, VOCs emission from over 80,000 km vehicles were about 46% larger than less 80,000 km vehicles. The difference in benzene and toluene according to driving mileage was 44% and 26% respectively. The composition of VOCs were different by fuel type. The order of VOCs composition was paraffins>aromatics>olefins in gasoline vehicle emissions, paraffins>olefins>aromatics in light duty diesel vehicle emissions. The VOCs emissions were decreased as vehicle speed increasing. These results will be used to calculate total VOCs emissions from automobiles in the future.