• Journal of Ocean Engineering and Technology
• /
• v.23 no.2
• /
• pp.92-97
• /
• 2009

In order to export aircraft components or substructures, it is necessary to get a certification from the main company for the components or an airworthiness certification from the FAA. In Korea, those processes are performed by a small number of private companies for aircraft components. However, airworthiness certification has never been done in the company. To export an assembled aircraft, whether small or large, it is obligatory to get a certification for the aircraft being exported. Currently, the Korean government is trying to get BASA agreement in a few years. For a mid-size company, it is easier to get the NADCAP audit process for the supply of aircraft components to the main company. In this paper, the overall process of aircraft certification is discussed and airworthiness certification is treated for export aircraft. Moreover, the NADCAP audit process is described in detail by introducing example parts made of composite material. This detailed process would be very helpful to a small or mid-size company that wants to develop and deliver aircraft components to foreign companies.

• Bulletin of the Korean Space Science Society
• /
• 2011.04a
• /
• pp.22.1-22.1
• /
• 2011

Two dominant components of polar motion are the Chandler and the annual components. Recently, the existence of 500-day period component in the Earth's polar motion has been manifested. But its existence is not clear on Fourier spectrum. One cause of difficulty involved here is that the amplitudes of the two main components are slightly variable in time by certain amounts (Chandler: 0.15~0.28 arcsec, annual: 0.09~0.15 arcsec). A residual polar motion time series excluding the two main components for a time span between 1962 Jan and 2010 Nov from IERS C04 time series dataset was constructed by least square fitting. For faithful fitting, 43 time segments of 6.8 year length (each starts on January 1st of successive years) were separately acquired and later combined together. The period of dominant peak in the spectrum of this residual polar motion time series is 490 days. Next peaks have their periods as semi-annual, 300~330 days, ~560 days, 670 days, and 1360 days.

• Preventive Nutrition and Food Science
• /
• v.6 no.2
• /
• pp.87-90
• /
• 2001

The volatile flavor components of snow crabs from the Young-duk coast of Korea and their concentrated cooker effluent were isolated by a modified method from Likens and Nickerson, using a simultaneous distillation and extraction apparatus. The concentrated extract was analyzed and identified by gas chromatography and GC-MS. The flavor profile of boiled crab demonstrated that the favorable flavor characteristic of crab involved a seafood-like note, and that of concentrated cooker effluent demonstrated that the weak boiled crab flavor involved a fishy note. The main flavor components of boiled crab were heterocyclic compounds including alkylpyrazines, thizoles and thiolanes, aliphatic ketones including 2-heptanone and nonanone. On the other hand, the main flavor components of cooker effluent were aldehydes including 3-methylbutanal, alipatic ketones including 2-heptanone and alkanes including 2,6,10,14-tetramethyl-pentadecane. Almost all of heterocyclic compounds, which seem to be important contributors to the flavor of boiled crab, were not identified in concentrated cooker effluent. As a result, there may be a need to add the crab flavor components formed through model experiments of Maillard reactions to the concentrated cooker effluent for human consumption.

• Korean Journal of Food Science and Technology
• /
• v.27 no.1
• /
• pp.36-40
• /
• 1995

Yam(Dioscorea) tubers were used as one of the dietary starches in Korea, China and Japan because of its characteristic properties. Yam tubers were powdered after freeze drying the sliced tubers to investigate carbohydrates. Chemical properties such as proximate components and carbohydrates were studied using three varieties of Korean yams, namely. D. batatas, D. aimadoimo and D. japonica. The proximate components of yam tubers showed that the major components of Korean yam tubers were carbohydrates and moisture. The main components of free sugars in yams were identified as fructose, glucose, sucrose and maltose. In addition to these four sugars, there were two unidentifiable peaks whose areas are too big to ignore. These results were obviously different from other reported data of free sugars in yams. The main components of total sugars were mannose and glucose.

• Journal of Institute of Control, Robotics and Systems
• /
• v.10 no.3
• /
• pp.249-254
• /
• 2004

The radiation dosage of nuclear fuel handling machine of PHWR type NPP during normal operation is measured using semiconductor detectors. In order to predict and mitigate the damage of main components in fuel handling machine, caused by high irradiation, the radiation dosage exerted to the components by neutron and gamma ray is measured independently during one time of the fuel exchange, which is used far estimating the radiation dosage for one year. This result can guarantee the safety and economical efficiency for determining the replacement time of the high cost main components in fuel handling machine.

• Asia pacific journal of information systems
• /
• v.7 no.2
• /
• pp.199-223
• /
• 1997

The purpose of this study is to identify the components of SME's information infrastructure through literature review, empirically investigate the components, and develop a model for SME's information infrastructure. The fact that SME's are having difficulties in building their own information infrastructure due to the limitation of capital investment, technology, and manpower is the main motive for the study The survey questionnaires were distributed to CEO's and users of 3W SME's and intensive interviews were cornea out to CIO's and information services personnel to further investigate H/W and S/W components of Information Infrastructure. The study results show that there seems to be five main factors for SME's information infrastructure. They are: (1) Informatization Capacity, (2) Software and Network, (3) Management Recognition and Utilization, (4) Hardware, and (5) Alignment between Users and Information Services.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.3
• /
• pp.143-151
• /
• 2001

Machine tool errors have to be characterized and predicted to improve machine tool accuracy. A real-time error compensation system has been developed based on volumetric error synthesis model which is composed of machine tool errors. This paper deals with new algorithm about verification of machine tool errors. This new algorithm uses a simplified volumetric error synthesis model. This simplified model is constructed with only main components among the error components of the machine. The main error components are analyzed by ball bar test of hemispherical helix. The novel measurement method using ball bar system has many advantages which are more efficient, easier to use than conventional measurement system.

• Korean journal of food and cookery science
• /
• v.12 no.3
• /
• pp.273-278
• /
• 1996

To investigate the main components of Korean traditional soy sauce for its typical taste, we compare the physicochemical properties of Korean traditional soy sauce and commercial soy sauce. The physicochemical analysis revealed that each components showed significant difference between Korean traditional soy sauce and commercial soy sauce. The significant characters for discrimination between Korean traditional soy sauce and commercial soy sauce were salt content, ammonia nitrogen content and total acidity (R$^2$=0.99). The components of Korean traditional soy sauce divided into 3 clusters, and each group is characterized as formol nitrogen, salt and total nitrogen content by cluster analysis. Main amino acids of Korean traditional soy sauce were alanine, glutamic acid, leucine and valine.

• YAKHAK HOEJI
• /
• v.54 no.1
• /
• pp.1-7
• /
• 2010

Valerian (Valeriana officinalis L.) is a perennial that has been used for medicinal purposes from the ancient times and valerian preparations including root and rhizome extracts are known to possess a variety of biological activities such as anticonvulsant, antidepressant, sleep aid, tranquilizer, and anti-HIV activities. Main components of the extracts were classified according to the structural features. Importantly, one of the main components, isovaleramide, has drawn our attention due to the concise structure, broad spectrum, and low toxicities. The general aspects including generation of this interesting molecule, a variety of activities, pharmacokinetic properties, derivatization, and fusion with other known drugs were described. Isovaleramide has been isolated from valerian probably as an isolation artifact after treatment of ammonia to prepare ammoniated tincture, and is known to exhibit anticonvulsant, anxiolytic, sedative, and sleep aid activities without distinct side effects such as excessive sedation and decreasing muscle tone. It was also found to be well absorbed into the circulation system without specific cytotoxicity and genotoxicity. The derivatives of isovaleramide, valpromide, valrocemide and valnoctamide were also briefly discussed.

• Natural Product Sciences
• /
• v.19 no.4
• /
• pp.297-302
• /
• 2013

The current study was conducted to evaluate the antibacterial and antioxidant activities of the essential oil fraction from the roots of Angelica tenuissima Nakai and its main components. We extracted the essential oil fraction from the roots of A. tenuissima using steam distillation and isolated its main components. Their antibacterial activities were determined by broth dilution test against food-borne pathogenic bacteria. Antioxidant activities were evaluated by DPPH-scavenging assay and reducing-power test. Also tested was their ability to inhibit the growth of two gastrointestinal cancer cell lines, Caco-2 and MKN-45. The A. tenuissima oil fraction and its main components, ligustilide and butylidene phthalide exhibited marked inhibitory effects against most of the tested antibiotic-susceptible and antibiotic-resistant bacterial strains with minimum inhibiting concentrations (MICs) from $0.21{\pm}0.08$ to $3.60{\pm}0.89mg/ml$. They also showed growth-inhibiting activity against Caco-2 and MKN-45 cells. The oil fraction showed significant antioxidant activities in DPPH radical scavenging assay and reducing-power test. Taken together, A. tenuissima essential oil could be used as a safe additive for preventing food contamination by pathogenic bacteria. Additionally, its antioxidative activity and the ability to inhibit gastrointestinal carcinoma cell lines could increase its value for functional foods and prevention of cancer.