• 대한방사성의약품학회지
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• 제6권2호
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• pp.177-181
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• 2020

Dual-modality imaging strategy using near-infrared fluorescence (FLI) and photoacoustic imaging (PAI) demands a suitable probe to enable dual-modular signal production. Herein, we demonstrate a synthetic protocol of small molecular dye for dual-modular FLI and PAI. A condensation reaction between squaric acid and carboxypentyl benzoindolium, and followed by basic hydrolysis to give the benzoindole derived squaraine (BSQ) dye in 49% yield. Next, the carboxylic acid group of BSQ was further functionalized with N-hydroxysuccinimide or azide group for an efficient conjugation with a targeting biomolecule. BSQ showed a maximum fluorescent emission at around 680 nm and the photoacoustic signal reached a maximum intensity at 680-700 nm. Based on these results, we conclude that BSQ analogs will be useful probes for dual-modular (FLI/PAI) imaging studies in animal models.

• Bulletin of the Korean Chemical Society
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• 제26권10호
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• pp.1555-1559
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• 2005

High-performance fluorescent probes which exhibit either on/off or dual color fluorescence switching in response to the presence of organic vapors with a rapid response, a high sensitivity and a high-contrast on/off signaling ratio were demonstrated on the basis of the vapor-controlled AIEE phenomenon.

• International Journal of Automotive Technology
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• 제3권1호
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• pp.33-40
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• 2002

Increasingly stringent emission regulations of EU and CARB (California Air resource Board) require mandatory OBD (On Board Diagnostics) far the catalytic converters of a vehicle. It demands that MIL(Malfunction Indication Light) should be tuned on to inform the driver of catalytic converter failures. Currently dual oxygen sensor method Is widely used for the converter OBD. However, since it works only alter converter light-off, it has a serious limitation when applied to TLEV or more stringent emission regulations where more than 85% of total emission is coming out before converter light-off. In addition, a recent development in catalyst material. coating technology and additive catalysts leads to a much improved OSC (Oxygen Storage Capacity) after converter light-off, current methods are very difficult to determine levels of converter aging. Therefore, it is desired to develop an OSC detecting method before converter light-off to diagnose converter failures with higher reliability. In this study, OSCs of converters are measured by an absolute measuring method and a dynamic measuring method, and some of fundamental ideas are suggested about converter OBD before converter light-off. The converters are aged with two different aging methods; those are a furnace aging and an engine bench aging: to represent aging conditions in actual field applications. Dual oxygen sensor method at the lower temperature than light-off is also studied at a model gas bench with the converters. It is fecund that there is a certain point in temperature lower than light-off where difference due to aging level becomes maximum, thus a proper dynamic method to effectively monitor catalytic converters could be implemented fur the range lower than light-off temperatures. With this result, the aging level of converters is examined at an engine bench.

• Bulletin of the Korean Chemical Society
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• 제9권3호
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• pp.171-175
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• 1988

The spectral properties of piroxicam in different solvents are similar to those of its skeletal precursor, HMBDC. The maximum absorption and emission wavelengths strongly depend on the hydrogen bonding ability of the solvent, and it is shown that intramolecular hydrogen bonding between the -OH and the ortho carbonyl group of the parent benzothiazine ring plays an important role in the solvent-dependence of their spectroscopic properties. The fluorescence spectra in aprotic nonpolar solvent exhibit abnormally large Stokes-shifted (${\sim}9,000cm^{-1}$) emission bands in contrast to the spectra in water. In ethanol, dual emission bands with two different fractional components of lifetimes have been observed. These results suggest that the abnormally red-shifted emission is attributed to the proton transferred form of an intramolecularly hydrogen-bonded closed conformer.

• 한국수소및신에너지학회논문집
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• 제31권4호
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• pp.372-379
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• 2020

Ammonia-hydrogen dual-fuel engine is a way to reduce greenhouse gas emission because ammonia and hydrogen are carbon-free fuels. In ammonia-hydrogen dual-fuel engine, hydrogen is supplied to improve the combustion characteristic of ammonia. In this study, an ammonia reformer was developed to supply hydrogen for 10 kW class ammonia-hydrogen dual-fuel engine. Thermodynamic characteristic and catalyst were investigated for ammonia reforming. Heat transfer was important for high ammonia conversion of ammonia reformer. 99% of ammonia conversion was obtained when 10 LPM of ammonia and 610℃ of hot gas were supplied to the ammonia reformer.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.112-120
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• 2005

The injector, which is used in a 4-valve gasoline engine, is required to be maintained the dual stream because of the design of dual intake port. In addition, the spray characteristics of fuel injector have strong influence on engine performance, exhaust emission, fuel consumption, and especially the cold start condition for the port injection. So, commercial gasoline injectors off different type were inspected. Those are 2 hole,4 hole, air shroud 4 hole, and air shroud 4 hole injector with separator. The spray behavior of dual stream was researched by the visualization system and PDPA system was employed to measure the droplet size. Atomization is one of the most important characteristic, so droplet size distributions and SMD are investigated. And the spray characteristics of each injector are also analyzed such as the spray tip penetration, spray angle, and separation angle.

• 한국자동차공학회논문집
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• 제3권3호
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• pp.9-18
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• 1995

The substitution of conventional fuel oil by alternative fuels is of immense interest due to liquid oil shortage and requirements of emission control standard. Among the alternative fuels, natural gas may be the most rational fuel, because of its widespread resource and clean est burning. Meanwhile, engine simulation is of great importance in engine development. Hence a zero-dimensional combustion model was developed for dual-fuel system. Natural gas was injected directly into the cylinder and small amount of distillate was used to provide the ignition kernel for natural gas burning. The intake air and exhaust gas flow was modeled by filling and emptying method. Although the single zone approach has an inherent limitation, the model showed promise as a predictive tool for engine performance. Its simulation was also made to see how the engine performance was influenced by the fuel injection timings and amount of each fuel.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.258-262
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• 2001

The contact resistivity was correlated with IFSS and microfailure modes in conductive fiber/cement composites electro-pullout and AE. As IFSS increased, the number of AE signals increased and the contact resistivity increased latter to the infinity. In dual matrix composite (DMC) test and AE, the number of signals with high amplitude and energy in g]ass fiber composite is significantly larger than that of no-fiber composite. Many vertical and diagonal cracks were observed in glass fiber and no-fiber composite under tensile test, respectively. Electro-micromechanical technique and AE can be used efficiently for sensitive nondestructive (NDT) evaluation and to detect microfailure mechanisms in various conductive fibers reinforced brittle and nontransparent cement composites.

• 한국수소및신에너지학회논문집
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• 제24권3호
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• pp.242-248
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• 2013

The purpose of this study is to obtain low-emission and high-efficiency by hydrogen enriched LPG fuel in LPG engine and is to clarify the effects of hydrogen enrichment in LPG fuelled engine on exhaust emission and performance. An experimental study was carried out to obtain fundamental data for performance and emission characteristics of hydrogen enrichment in LPG engine. The research was held by changing the hydrogen ratio to 0, 5, 10, 20% in 1500rpm, bmep 2 and 4bar. The result turned out that the combustion duration was shortened due to fast flame propagation of hydrogen. And the amount of Carbon dioxide and Hydrocarbon decreased. However, the amount of NOX increased, which is thought to be the result of high adiabatic flame temperature of hydrogen. It has been confirmed that this phenomenon has changed by the Hydrogen mixing ratio.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.213-218
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• 1997

CNG dual fuel engine for heavy duty diesel engine has been equipped to a Korean bus engine and tested to compare th engine performance and the emission characteristics with the existing diesel fueled engine. The results are summarized as follows. Diesel fueled engine has the fuel injection timing of BTDC17°. The injection timing of CNG modified engine is retarded to BTDC14° for reduction of NOx. Performance optimization has been carried out to have engine power equivalent to or better than the diesel fueled engine. Smoke is decreased by 85% by Korean smoke 3 mode test. By 6 mode test CO is increased by 313% and THC is increased by 1407%. NOx is decreased by 27%. Even though THC is increased very much, it's not too serious problem since CO and THC emission of diesel engine are very little compared to gasoline engine and THC don't give bad effect on human health. But the reduction technologies of CO and THC need to be considered.