• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.3
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• pp.478-483
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• 1996

The aroma components of Korean green tea in the south western part of Mt. Chiri prepared by the traditional method from native variety were analyzed using GC and GC-MS. The patterns on GC chromatograms of the three samples from the flushes plucked in early spring were similar, though they are prepared by different producers in the area of Hadong-kun, Kyung sang nam-do. A total of 51 aroma compounds were identified in all samples. Main component in the aroma compounds of these teas were geraniol, benzyl alcohol, 2-phenylethanol, $\beta$-ionone, benzyl cyanide and linalool oxides. The aroma components of green teas manufactured by the different plucking periods were also compared. The amounts of geraniol, typical rose floral aroma were particularly decreased in the final plucking period. The amounts of pyrazines and furfuryl alcohol, typical roasted aroma and nutty aroma were slightly increased in later plucking period.

• The Korean Journal of Food And Nutrition
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• v.12 no.5
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• pp.513-517
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• 1999

Theessential oils of anise darkopal lettuce and sweet basils cultivated in Korea were extracted by simulatneous steam distillation and extraction method and were analyzed by GC/MSD. Total 41 com-ponents were identified in essential oils including 11 alcohols, 6 carbonyls 19 hydrocarbons and 5 esters components. The major components were 1,8-cineole linalool $\alpha$-bergamotene $\beta$-elemene methyl chavicol, $\beta$-cubebene methyl cinnamate and eugenol. Darkopal lettuce and sweet basils were rich in linalool(30.1-36.5%) methyl chavicol(8.1-25.5%) and relatively poor in methyl cinnamate(0-2.71%) Anise basil was rich in linalool(28.5%) and methyl cinnamate(23.1%) However methyl chavicol which was known as one of the main components of bisil was not detected.

• Journal of Power System Engineering
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• v.14 no.6
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• pp.61-66
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• 2010

Engineering asset management (EAM) requires the accurate assessment of current and the prediction of future asset health condition. Suitable mathematical models that are capable of predicting time-to-failure and the probability of failure in future time are essential. In general reliability models, lifetime of component and system is estimated using failure time data. This paper deals with the reliability assessment of elevators using life of main components. Especially this work is concerned with the stochastic nature of life of elevator components. First, we investigate the Weibull statistical analysis of lifetime data for the components. The final goal is to establish the mathematical model for reliability assessment. This work provides more perspectives to future research in the fields of reliability and maintainability.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.2
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• pp.155-160
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• 1990

During the period from Mar. 1985 to Feb. 1988, airborne particulate matters were collected and size fractionated by the ANdersen high volume air sampler in Seoul. The concentrations of several heavy metals (Pb, Cu, Zn, Fe, Mn) and benzo(a)pyrene were determined to investigate the size distributions and seasonal variations. And with respect to seven components in the total suspended particulate (TSP), the factor analysis was performed for three groups such as the coarse particles (> 2 $\mu$m), fine particles (< $\mu$m) and TSP. As a result of factor analysis by using the varimax method, the chemical components in the TSP were able to characterize with two principal factors. The first factor, F1 was considered to be a factor indicating the contribution of natural sources and the second factor, F2 was a factor indicating the degree of artificial sources. Each components in the TSP was divided into two main groups of components originated from soil and/or road dust and pollutants originated from automobiles and/or human work.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.563-567
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• 1998

Volatile flavor components of edible portion of leek(Allium tuberosum R.) were extracted by SDE(simultaneous steam distillation and extraction) method using the mixture of n-pentane and diethylether (1 : 1, v/v) as an extract solvent and analyzed by GC-FID and GC/MS. Identification of the volatile flavor components was mostly based on the RI of GC and mass spectrum of GC/MS. A total of sixty-five components from leek extract were classified as 28 sulfur-containing compounds, 12 aldehydes, 9 alcohols, 4 lactones and esters, 3 acids and hydrocarbons, and 2 miscellaneous compouds. The sulfur-containing compounds were predominant in leek extract. Dimethyl disulfide(19.47%) and dimethyl trisulfide(17.38%) were the main compounds and trans-1-propenyl methyl disulfide, trans-2-hexenal and methyl allyl disulfide were also detected large amounts in leek.

• ETRI Journal
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• v.35 no.2
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• pp.340-343
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• 2013

A novel bumping process using solder bump maker is developed for the maskless low-volume solder on pad (SoP) technology of fine-pitch flip chip bonding. The process includes two main steps: one is the aggregation of powdered solder on the metal pads on a substrate via an increase in temperature, and the other is the reflow of the deposited powder to form a low-volume SoP. Since the surface tension that exists when the solder is below its melting point is the major driving force of the solder deposit, only a small quantity of powdered solder adjacent to the pads can join the aggregation process to obtain a uniform, low-volume SoP array on the substrate, regardless of the pad configurations. Through this process, an SoP array on an organic substrate with a pitch of $130{\mu}m$ is successfully formed.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1508-1513
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• 2006

Currently, the Korean railway safety law (RSL) and its ordinances have been enforced for the guarantee of the safety of railway. In RSL, the quality certification is required to guarantee the safety and performance of railway components or systems. However, not much attention has been focused on the quality certification scheme for railway components or systems since the scheme is relatively new. Therefore, in this investigation, the detailed guidelines and main contents for the enforcement of quality certification for railway components will be suggested, and the detailed items including the procedures, subjects, management, etc., will be addressed. Moreover, a better understanding on quality certification for railway components will be provided.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.6
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• pp.761-769
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• 2012

In this paper, we propose a low-power design strategy to minimize energy-consumption for surveillance and reconnaissance sensor networks. The sensor network consists of many different nodes with various operations such as target detection, packet relay, video monitoring, changing protocols, and etc. Each sensor node consists of sensing, computing, communication, and power components. These components are integrated on a single or multiple boards. Therefore, the power consumption of each component can be different on various operation types. First, we identified the list of components and measured power consumption for them from the first prototype nodes. Next, we focus on which components are the main sources of energy consumption. We propose many energy-efficient approaches to reduce energy consumption for each operation type.

• Biomedical Engineering Letters
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• v.8 no.4
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• pp.355-364
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• 2018

When focusing using an ultrasonic transducer array, a main lobe is formed in the focal region of an ultrasound field, but side lobes also arise around the focal region due to the leakage. Since the side lobes cannot be completely eliminated in the focusing process, they are responsible for subsequent ultrasound image quality degradation. To improve ultrasound image quality, a signal processing strategy to reduce side lobes is definitely in demand. To this end, quantitative determination of main and side lobes is necessary. We propose a theoretically and actually error-free method of exactly discriminating and separately computing the main lobe and side lobe parts in ultrasound image by computer simulation. We refer to images constructed using the main and side lobe signals as the main and side lobe images, respectively. Since the main and side lobe images exactly represent their main and side lobe components, respectively, they can be used to evaluate ultrasound image quality. Defining the average brightness of the main and side lobe images, the conventional to side lobe image ratio, and the main to side lobe image ratio as image quality metrics, we can evaluate image characteristics in speckle images. The proposed method is also applied in assessing the performance of side lobe suppression filtering. We show that the proposed method may greatly aid in the evaluation of medical ultrasonic images using computer simulations, albeit lacking the use of actual experimental data.

• Journal of the Korean Mathematical Society
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• v.47 no.2
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• pp.311-329
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• 2010

In this paper we will prove that the groups $D_{p+1}$(2) and $D_{p+1}$(3), where p is an odd prime number, are uniquely determined by their sets of order components. A main consequence of our result is the validity of Thompson's conjecture for the groups $D_{p+1}$(2) and $D_{p+1}$(3).