• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.7
• /
• pp.769-776
• /
• 2011

In order to cope with the requirements of smaller patterns, larger surfaces and lower costs in the fields of displays, optics and energy, greater attentions is now being paid to the development of micro-pattern machining technology. Compared with flat molds, roll molds have the advantages of short delivery, ease of manufacturing larger surfaces, and continuous molding. This paper presents the state-of-the-art of the micro pattern machining technology on the roll molds and introduces some research results on the machining process technology. The copper and nickel-phosphorous-alloy plating process, machining process technology for uniform micro patterns. micro cutting simulation and the real time monitoring system for micro machining are summarized. The developed technologies have led the complete localization of the prism sheets and will be applied to the direct forming process with succeeding research & development.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.153-153
• /
• 2013

Turbomolecular pump (TMP) is widely used to obtain and maintain high vacuum by spinning turbine rotors to migrate gas molecules to the exhaust of the pump. However, performance of the TMP has not been well observed when it is influenced by strong magnetic field. Such study may give useful information about magnetic field tolerance of TMP, development of magnetic shielding technique for key components of TMP, etc. For this purpose, magnetic field induced by a circular current source was firstly designed and investigated. Using spherical coordinates and vector potential, magnetic field throughout the space including axis of rotation was calculated. Due to the rotational symmetry of the circular current source, induced magnetic field is azimuthally symmetric and, thus, is analyzed by radial and polar components of the magnetic fields. In order to enhance the numerical accuracy for the calculation, magnetic field was expressed by complete elliptic integrals of first and second kinds. According to the calculation, when 1 A of DC-current passes through a 1 turned circular wire with 50 cm of diameter, overall magnitude of the inducedmagnetic field was about 0.02 Gauss, which was used to the determination of the current and the number of turns of wires to fabricate the coil for the study on the magnetic field tolerance of TMP.

• Wind and Structures
• /
• v.24 no.2
• /
• pp.119-144
• /
• 2017

The traditional method for the simulation of high Reynolds number (Re) effects on wind loads on cooling tower models in wind tunnels focuses only on the mean wind pressure distribution. Based on observed effects of some key factors on static/dynamic flow characteristics around cooling towers, the study reported in this paper describes a comprehensive simulation method using both mean and fluctuating wind pressure distributions at high Re as simulation targets, which is indispensable for obtaining the complete full-scale wind effects in wind tunnels. After being presented in this paper using a case study, the proposed method is examined by comparing the full covariance matrices and the cross-spectral densities of the simulated cases with those of the full-scale case. Besides, the cooling tower's dynamic structural responses obtained using the simulated wind pressure fields are compared with those obtained by using the full-scale one. Through these works, the applicability and superiority of the proposed method is validated.

• Proceedings of the Korea Database Society Conference
• /
• 2010.06a
• /
• pp.13-19
• /
• 2010

Information competitiveness accounts for substantial parts of business competitiveness necessary for business management in the knowledge-information society in the 21st century. To improve quality. productivity and competitiveness through information in the fields of SMEs particularly having difficulties under rapidly changing business environment. the government has operated "SME Information Support Project" for the past 8 years. The methodology for developing the standard for this project known as EISDM (Enterprise Information System Development Methodology) provides communication between IT businesses and SMEs participating in this project. and standardized output document formats and how to make out such documents. Infortunately. the number of personnel partaking in the development project for SMEs is no more than 2~4 per site on average. Further. they are required to complete demand analyses. development. testing and operation in about 6 months. which is a very short period. Moreover, there is too much demand for documentation, which is likely to end up being formal work process just for supervision and inspection. That is, the documentation could be for noting but documents. which will prove useless outputs after the project finishes. Therefore, this study proposes an improvement approach as an information system development methodology taking into account SMEs' characteristics and environment so as to relieve developers from such excessive burden of documentation, to save time and resources through efficient management of software development as the original purpose of the methodology, and to produce required quality software.

• Journal of Plant Biotechnology
• /
• v.5 no.4
• /
• pp.239-244
• /
• 2003

A protocol has been developed for rapid large scale clonal propagation of an aromatic endangered medicinal plant, Hemidesmus indicus R. Br. with the elimination of the problems such as premature leaf fall and callus formation during caulogenesis and rhizogenesis. Multiple shoots were induced from shoot tip and nodal explants on Murashige and Skoog (MS) medium supplemented with 1 mg/L Benzylaminopurine (BAP) and 0.5 mg/L Napthaleneaceticacid (NAA). Addition of 15 mg/L adenine sulphate to the above medium checked leaf abscission completely, reduced the time required for caulogenesis and restored morphogenetic potential after several subcultures. The in vitro grown propagules were rooted in 1/2 MS medium supplemented with 2 mg/L Indolebutyric acid (IBA) +1 mg/L NAA and sucrose 0.7% (w/v). Addition of charcoal at 100 mg/L to the rooting medium quickened root initiation with a complete check on callus formation. The effect of sucrose concentration on both caulogenesis and rhizogenesis was also studied. The resultant plantlets were acclimatized and grown in fields where ninety eight percent of the rooted shoots survived and grew normally. The estimation of the secondary metabolite content in the shoots of the regenerated plant and the mother plant indicated that the concentration of the three secondary metabolites lupeol, vanillin and rutin was similar.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.8
• /
• pp.3617-3619
• /
• 2012

Background: The completeness of cancer registration is a major validity index of any reported cancer incidence. The present study aimed to evaluate the esophageal cancer incidence registered in the Tehran Metropolitan Area Cancer Registry. Materials and methods: The data on esophageal cancer abstracted from three sources of 1) pathology departments, 2) medical records, and 3) death certificates during 2003 till 2007 were utilized. The completeness of the data sources were evaluated using coverage (defined as the proportion of a community population with esophageal cancer identified by the source) and density (defined as the proportion of non-empty fields of the data by source). Results: A total 1,404 cases of esophageal cancer were reported for the duration of the study. Pathology provided 771, medical records 432, and death certificates 609. The coverage was 0.55 for pathology, 0.31 for medical records, and 0.43 for death certificates. The respective density values were 0.82, 0.96 and 0.98, respectively. Pathology (0.45) was the most complete source followed by medical records (0.42), and death certificates (0.29). Discussion: A low degree of completeness dictates putting more effort into case finding plus abstracting data more thoroughly.

• Asia-Pacific Journal of Business
• /
• v.7 no.2
• /
• pp.1-19
• /
• 2016

This study has analyzed the interrelation between transformational leadership (TL) and organizational commitment (OC) so as to verify the mediating effect of their trust on OC, finding that charisma and intellectual stimulus have a significant effect on affective and continuous commitment. This finding is different from any existing arguments where the charisma of TL and the individual consideration are said to have a significant and positive effect on affective and continuous commitment. Furthermore, the mediating effect, which was expected to be highly relevant on the grounds of the findings of previous researches that any high trust of a leader would lead to a high level of OC of members, has been revealed as a complete mediation in the relationship of emotional trust between individual consideration and OC, which shows that the correlation between TL and OC may vary depending on the characteristics of an organization and its members both of which are sample objects. This study, unlike most previous researches with their research samples in industrial fields, has estimated the growing interrelation of NGOs. Therefore, while this study itself may have its research-limit of specificity, it is expected to make a useful contribution to any future researches of the same category.

• The Journal of Engineering Research
• /
• v.3 no.1
• /
• pp.159-169
• /
• 1998

The purpose of this study is to analyze the radiation characteristics of the shaped Cassegrainian antenna. Radiation pattern of the sub-reflector is calculated by GTD (Geometrical Theory of Diffraction) The complete radiation patterns are obtained by summing the reflect field from the surface and the diffracted fields from the edge. The first and the second derivative on the sub-reflector are calculated by the local interpolation technique. The Radiation characteristics of the main-reflector are obtained by integrating the surface current density, which is derived from PO approximation. The radiation integral is expanded by the Jacobi-Bessel series for the purpose of reducing the computation time.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.25 no.6
• /
• pp.467-474
• /
• 2005

The expanded multi-Gaussian beam model has recently been developed that can calculate the radiation beam field from a single, rectangular transducer with great computational efficiency. In this study, this model is adopted to calculate the radiation beam field for a phased array transducer with various time delays to achieve steering and/or focusing. The calculation beam fields are compared to those obtained by well known Rayleigh-Sommerfeld integral that provides the exact solution in order to explore the validity of the expanded multi-Gaussian beam model And then, this study proposes a complete ultrasonic measurement model including the expanded beam model, far-field scattering model and system efficiency, Using the proposed model, phased array ultrasonic testing signals for a flat-bottomed hole with/without focusing were performed.

• Advances in pediatric surgery
• /
• v.17 no.1
• /
• pp.72-80
• /
• 2011

Although laparoscopic surgery for hepatobiliary disease in children is possible, it is technically challenging. In an attempt to overcome these difficulties, the da Vinci Robotic Surgical System$^{(R)}$ was used to facilitate the minimally invasive treatment of choledochal Cyst in six children. In early consecutive three cases, we experienced three complications; a case of laparotomy conversion, a case of late stenosis of the hepaticojejunostomy, and a case of leakage from a hepaticojejunostomy. However, in the last three cases the complete resection of the choledochal cyst and Roux-en-Y hepaticojejunostomy were performed using the robotic surgical system without complication. We think robot-assisted choledochal cyst resection in children appears safe and feasible, and may increase the variety of complex procedures in pediatric surgical fields.