• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.171-176
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• 2003

A Test Facility was established to carry out the integrated propulsion performance tests(IPPT). To perform IPPT's with maximum safety, an emergency blockage system was investigated. An emergency blockage system using combustion chamber pressure and acceleration signals was set up to monitor ignition delay and fail, flame out, propellant feeding status, unstable combustion and excessive structural vibration. With such system, the maximum safety could be secured by rapid judgement and follow-up measures, which made IPPT's be safely completed.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.985-989
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• 1990

This paper presents a fundamental study of a millimeter-sized master-slave robot driven by conduit-guided wires, which is expected to be applied to the delicate surgical operations, the assembling precise and small parts and so on. This system consists of a millimeter-sized slave robot and a master manipulator of which the size is adapted to a human finger. Displacement and torque of the master side can be reduced and transferred to the slave robot by controlling the motor torque against the master torque by feeding back tension signals. The master can feel the tensions by the motor torque. In this paper, the design method and making process of the master-slave system and the dynamical characteristic of displacement and torque control are proposed.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.76-83
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• 2006

Machining accuracy is closely related with tool deflection induced by cutting forces. In this research, cutting forces and tool deflection in end milling are expressed as a closed form of tool rotational angle and cutting conditions. The discrete cutting fores caused by periodic tool entry and exit are represented as a continuous function using the Fourier series expansion. Tool deflection is predicted by direct integration of the distributed loads on cutting edges. Cutting conditions, tool geometry, run-outs and the stiffness of tool clamping part are considered together far cutting forces and tool deflection estimation. Compared with numerical methods, the presented method has advantages in prediction time reduction and the effects of feeding and run-outs on cutting forces and tool deflection can be analyzed quantitatively. This research can be effectively used in real time machining error estimation and cutting condition selection for error minimization since the form accuracy is easily predicted from tool deflection curve.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.767-770
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• 2000

A novel process is newly developed for building RP(Rapid Prototyping) parts using a sheet lamination technique. The build process of existing sheet lamination type RP machines consists of the following steps : feeding, lamination and cutting. In this process, the laminated part of an object is often scratched by a cutter or damaged by a laser beam due to the cutting operation preceded by lamination, In addition, decubing of the unused portion from the laminated block is difficult. In the new process, cutting operation is performed before lamination. The cutting operation takes place while a paper sheet is firmly attached on the plate using electrostatic force. Then liquid glue is applied to the calculated region of the given contour for lamination. The process aims to manufacture a $2k RP machine, what we call the Freeform Mater I, that can use A4 or latter-size used papers. A prototype machine that demonstrates the design concept is built and further research issues are discussed.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.3
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• pp.183-186
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• 1990

Monensin administered as a slow release capsule to Droughtmaster steers grazing mixed pastures containing Stylosanthes hamata or grass pastures fertilized with N, had no effect on growth rate over 111 day period. Monensin significantly increased the level of propionic acid (p<0.001) and decreased the level of butyric acid (p<0.01) in the rumen. The lack of response to monesin was partly attributed to the poor pasture conditions and growth rate of the steers during part of the experimental period. An implant of oestradiol improved growth rates during the period of poor forage quality and in the subsequent 56 days when pastures were of high quality following rain. Mean growth rates over the entire 157 days for control, monensin and monensin/oestradiol treatments were 0.37, 0.37 and 0.50 kg/d respectively. It was concluded that when pasture conditions are sufficient only for the maintenance of liveweight, production can be improved by an oestradiol implant but not by feeding an ionophore such as monensin.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.56-61
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• 2008

Cropping metal materials is widely used for feeding processes of various forming method, such as forging, extrusion, drawing, and upsetting. However, cropping has many weak points, which are material loss in part of cutting, chip creation, and much use of lubrication oil, etc. In this study, instead of cropping, a novel process is proposed to cut metal materials, especially stainless steel bar which is known very difficult to crop. Results of FE-analysis will be shown to verify the proposed method comparing with those of the conventional cropping process. Also, fitting products were successfully forged using the fabricated billet by the proposed process.

• Journal of Korea Foundry Society
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• v.27 no.4
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• pp.173-178
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• 2007

The bearing bracket, which has produced by the squeeze casting for the high strength in lightweight part of automobile, was developed by the rheocasting process using the H-NCM slurry. Compared with the squeeze casting, the rheocasting process has some merits such as shortening cycle-time, reducing total weight, and increasing productivity. In this study, partial feeding test was carried out by controlling plunger stroke length and compared with semisolid simulation. Optimal casting parameters such as injection speed and stroke variations were established. Sound products with integral microstructure were obtained by the H-NCM slurry and X-ray analysis also showed the integral condition throughout the entire parts.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.143-152
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• 1996

The vibratory bowl feeder is the most versatile of all hopper feeding devices for small engineering parts, and the typical nonlinear dynamic system experiencing repeated impacts with friction. We model and analyze the dynamic behavior of a single part on the vibrating track of the bowl feeder. While the previous studies are restricted to the sliding regime, we focus our analysis on the hopping regime where the high conveying rate is available. We present the numerical analysis results for conveying rate and frictional impact process both in periodic and chaotic regimes. We examined the dynamic effects from the variation of several physical parameters, and presented the important features for the design of the vibratory bowl feeder. This research holds much potential for leverage over design problems of wide range of mechanisms and tools with repeated collisions.

• Journal of the Korean Society of Food Culture
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• v.17 no.3
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• pp.252-259
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• 2002

The purpose of this study examined important factor of performance on Contract Foodservice management. Three contract Foodservice companies were selected which were located in Seoul & kuonggi province. 300 units were chose. The questionnaire was composed of seven part. There were the operation of food management, the operation of menu, the operation of equipment and facilities management, the operation of solid waste and safety management, the operation of waiting time management. As a result of the survey B&I foodservice was listed higher than University foodservice as food hygiene, FIFO and food shelf life. University foodservice employees worked 4 hour longer than B&I foodservice employees, so turnover rate was higher than it. Comparing the number of feeding, B&I foodservice equipment and facilities scale was bigger than University foodservice equipment and facilities. The rate of solid waste on B&I foodservice was 11.468% and the rate of University foodservice was 16.23%, the waiting time of University foodservice was about 8mins longer than B&I foodservice.

• Proceedings of the Botanical Society of Korea Conference
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• 2002.04a
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• pp.73-82
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• 2002

The committing step in Met and S-adenosyl-L-methionine (SAM) synthesis is catalyzed by cystathionine ${\gamma}$ -synthase (CGS). Transgenic Arabidopsis thaliana overexpressing CGS under control of 35S promoter show increased soluble Met and its metabolite S-methylmethionine, but only at specific stages of development. CGS-overexpressing seedlings are resistant to ethionine. Similar results were obtained with transgenic potato plants overexpressing Arabidopsis CGS. Several of the transgenic lines show silencing of CGS resulting in deformed p]ants with a reduced capacity for reproductive growth similar as transgenic plants by antisense RNA (CGS[-]). Exogenous feeding of Met to the CGS[-] and CGS[+] silenced plants partially restores their growth. Similar morphological deformities are observed in plants cosuppressed for SAM synthetase, even though such plants accumulate 250 fold more soluble Met than wild type and they overexpress CGS. The results suggest that the abnormalities associated with CGS and SAM synthetase silencing are due in part to a reduced ability to produce SAM, and that SAM may be a regulator of CGS expression.