• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1237-1241
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• 2003

In this paper, we report a novel RF-MEMS packaging technology with lightweight, small size, and short electric path length. To achieve this goal, we used the ultra thin silicon substrate as a packaging substrate. The via holes lot vortical feed-through were fabricated on the thin silicon wafer by wet chemical processing. Then, via holes were filled and micro-bumps were fabricated by electroplating. The packaged RF device has a reflection loss under 22 〔㏈〕 and a insertion loss of -0.04∼-0.08 〔㏈〕. These measurements show that we could package the RF device without loss and interference by using the vertical feed-through. Specially, with the ultra thin silicon wafer we can realize of a device package that has low-cost, lightweight and small size. Also, we can extend a 3-D packaging structure by stacking assembled thin packages.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.73-80
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• 1993

There and two important variables in machining process control, which are feed and cutting speed. It is possible to improve the machining accuracy and the productivity by maintaining the optimal feed and cutting speed. In this work, a controller is designed to achieve on-line cutting force control based on the modeling of cutting process dynamics established through step response test. Two schemes are proposed and implemented. The first is feed control under the constant spindle speed and the second is spindle speed control under the constant feed. Finally, both are proved to work properly through simulation and experimentation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.131-132
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• 2010

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.101-107
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• 2018

The impedance bandwidth and radiation characteristics of an aperture-coupled microstrip line-fed patch antenna (ACMPA) with a high permittivity (${\varepsilon}_r=10$) feed substrate suitable for integration with a monolithic microwave integrated circuit (MMIC) are investigated for various feed substrate thicknesses through an experiment and computer simulation. The impedance bandwidth of an ACMPA with a high permittivity feed substrate increases as the feed substrate thickness decreases. Furthermore, the front-to-back ratio of an ACMPA with a high permittivity feed substrate increases and the cross-polarization level decreases as the feed substrate thickness decreases. As the impedance bandwidth of an ACMPA with a high permittivity feed substrate increases and its radiation characteristics improve as the feed substrate thickness decreases, the ACMPA configuration becomes suitable for integration with an MMIC.

• Membrane Journal
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• v.13 no.4
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• pp.257-267
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• 2003

For the treatment of reactive phenolic resin waste, a simulation model of pervaporative dehydration process has been developed through hollow fiber membrane module. Some of basic parameters were determined directly from dehydration of the waste liquid through a flat sheet membrane to get realistic values. The simulation model was verified by comparing the simulated values with experimental data obtained from hollow fiber membrane module. Hollow fiber membranes with active layer coated on inside fiber were used, and feed flew through inside hollow fiber. Feed flow rate affected membrane performances and reaction by providing a corresponding temperature distribution of feed along with fiber length. Feed temperature is also a crucial factor to determine dehydration and reaction behavior by two competing ways; increasing temperature increases permeation rate as well as water formation rate. Once the permeate pressure is well below the saturated vapor pressure of feed, permeate pressure had a slightly negative effect on permeation performance by slightly reducing driving force. As the pressure approached the vapor pressure of feed, dehydration performances declined considerably due to the activity ratio of feed and permeate.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.6
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• pp.830-836
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• 2000

A participation scheme involving smallholder dairy farmers in improving dairy productivity through the use of local feeds, on-farm established feeds and crop residues was carried out in the Northeast, Thailand. At six milk collection centers, 63 farmers with 340 lactating cows participated in this research and demonstration of feed supplements. Farmers and cows were allotted to receive respective feed supplements: high-quality feed block (HQFB), high-quality feed pellet (HQFP), dried cassava leaf/cassava hay, dried leucaena leaf and cottonseed meal: 5% urea treated rice straw was fed as a source of roughage throughout the feeding period of the dry season. Trainings and workshops were organized by the researchers at the University, research station, demonstration sites and on-farms. Regular visits to the fartns by researchers and extension officers were made while discussions and demonstrations were performed in addition. Participating farmers also visited other farmers during the demonstration which offered a real practical perspective and farmer-to-farmer interaction. As a result of this participation and demonstration scheme, the farmers could learn more effectively and accepted the technology more readily, especially the practicality of the feed preparation, feed establishment, feeding method and feed reserve. Strategic supplementation of these feed supplements resulted in improving milk yield, milk quality, overall condition of the cows and higher income return through increased productivity and lower level use of concentrate to milk yield from 1:2 to 1:3 or lower. Based on this research and demonstration /participation scheme, all feed supplements enhanced productivity, however the establishment of cassava hay on fartns deserved more attention and warrants a wider developmental expansion among dairy farmers since it contained high rumen by-pass protein (tannin-protein complex) and could be easily produced and be sustainable on farms.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.279-284
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• 2000

It can be acquired the high effective productivity through of high speed, precision of machine tools, and then, machine tools will be got a competitive power. Industrially advanced countries already developed that the high speed feed is 60m/min using the high speed ball screw. Also, a lot of problems have happened the feed drive system. It is necessary to study about the character of positioning accuracy, heat generation and high speed control for feed drive system of high speed. in this study, we make use of the feed drive system with a high lead ball screw. We'll develop the feed drive system at the speed of 60m/min. Using the design of the mechanical element and the high speed control, the basic design concept can be established. After manufacturing one-shaft feed drive system and then conducting the performance test, It'll be analyzed properties of the high speed feed drive system.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.39-44
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• 1999

It can be acquired the high effective productivity through of high speed, precision of machine tools, and then, machine tools will be got a competitive power. Industrially advanced countries already developed that the high speed feed is 60m/min using the high speed ball screw. Also, a lot of problems have happened the feed drive system. It is necessary to study about the character of positioning accuracy, heat generation and high speed control for feed drive system of high speed. In this study, we make use of the feed drive system with a ball screw of large-scale-lead. We'll develop the feed drive system at the speed of 60m/min. Using the design of the mechanical element and the high speed control, the basic design concept can be established. After manufacturing one-shaft feed drive system and conducting the performance test, it'll be analyzed properties of the high speed feed drive system.

• Animal Bioscience
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• v.36 no.10
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• pp.1546-1557
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• 2023

Objective: The present study aimed to evaluate the effects of extruded and unextruded feeding on the performance, milk composition, digestibility and ruminal fermentation of dairy cows through a meta-analysis. Methods: The database was compiled from 53 studies in Scopus and PubMed. The data were analyzed using a random effects model in OpenMEE software. Extruded feed was grouped as the experiment group while and the others as control group. The bias of publication in the main parameter of dairy performance was evaluated by a funnel plot. Results: The result showed that extruded feed enhanced the milk yield, dry matter and crude protein digestibility, butyrate and valerate acid production (p<0.05). Meanwhile, the extruded feed significantly decreased the milk fat and protein concentration (p<0.05). Also, the iso-butyrate and iso-valerate in unextruded feeding was significantly higher than the extruded feed (p<0.05). Conclusion: It was concluded from the meta-analysis that extruded feed effectively improved the milk production and milk lactose concentration, dry matter and protein digestibility, but not the milk fat and protein concentration.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.70-77
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• 2003

The centerless through-feed grinding is performed by passing the workpiece between the grinding wheel and the regulating wheel. So, the amount of removed material around the leading end, of the workpiece is always more than that around the trailing end until the leading end leaves the grinding wheel. Because of this, there are differences in diameters along the workpiece axis during grinding, and workpiece axis is not parallel to the grinding wheel axis and the contact lines between the workpiece and wheels. Thus the ground workpiece shows tapering error inherently. To eliminate this error, the workpiece axis must be kept to be parallel to the grinding wheel axis. And, the direction of the workpiece axis can be controlled by the work-rest blade. Therefore, the effects of work-rest blade inclination angle on the through-feed centerless ground part are investigated in this study. As a result, it is found that there is a positive inclination angle of the work-rest blade for minimizing the tapering error of a ground workpiece.