• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1204-1209
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• 2006

Grouting operate to reinforce expanded clay ground. Cement grouting is one of the most frequently used techniques for underground construction. This work is going to use to add an electrolytic ion to boring water for expanded reduction. To construct underground structures on expanded clay ground is operated pre-grouting that it is the barrier wall previous excavation to prevent an accident. Grouting for early compressive strength development is made a type of suspension. That grouting aims to prevent the swelling magnification in length of time. From now on, grouting is became a type of higher strength suspension to develop early compressive strength.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.96.5-96
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• 2001

The probe with a 110mm diameter is originated and fabricated to measure hole accuracies of extremely deepholes. It consists of a measuring unit, an actuator unit, an active rotation stopper and a feed unit. The rolling of the probe is restricted and adjusted by the active rotation stopper. The probe is fed by the feed unit. In this measurement, accuracies are measured by using a rolling proof apparatus and machine table of deep hole boring machine instead of the stopper and the feed unit, respectively. Straightness, roundness and a diameter of a 110-mm hole are measured by the probe and testers made for each measuring purpose ...

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.1
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• pp.10-16
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• 2002

This study is to evaluate the tool performance in honing using diamond reamer and present grounds whether the localized products are sufficiently competitive comparing with the existing imported ones. The heads of the tool performance evaluation are roundness, roughness, tool life of the workpiece and so on. When evaluating the tool performance, cutting process is divided by three areas which are rough semi-finish and finish cut. cloning improves the accuracy such as boring and reaming after manufacturing the inside diameter, and finishing directly by honing is a recent trend. This honing is used greatly In hard cutting materials like cemented carbides and it is the CBN and diamond that is used in hard cutting materials. Both of them are expensive and most oi them are imported.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.3
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• pp.42-51
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• 1999

An experimental modeling of cutting and structural dynamics and the on-line detection of malfunction process is substantial not only for the investigation of the static and dynamic characteristics of cutting process but also for the analytic realization of diagnostic systems. In this regard, We have discussed on the comparative assessment of two recursive time series modeling algorithms that can represent the machining process and detect the abnormal machining behaviors in precision round shape machining such as turning, drilling and boring in mold and die making. In this study, simulation and experimental work were performed to show the malfunctioned behaviors. For this purpose, two new recursive approach (REIVM, RLSM) were adopted fur the on-line system identification and monitoring of a machining process, we can apply these new algorithm in real process for the detection of abnormal machining behaviors such as chipping, chatter, wear and round shape lobe waviness.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.5-19
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• 1995

항공기 기술의 발전은 다양한 과학기술 분야의 발달에 끊임없이 큰 영향을 주어왔고, 또 기기서 파생된 신 기술도 수없이 발생하였다. NC 공작기계도 그 하나이다. 제 2차 세계대전 후 미공군은 복잡한 형상의 항공기 부품가공과 고정밀도의 검사용 Gauge를 제작할 필요성을 얻게 되었다. Helicopter의 Rotor blade의 Prifile 검사용 Plate gauge를 가공할 수 있는 기계를 개발 중에 있었던 J.T.Person이 Jig boring machine을 저자적으로 제어하면서 Gauge를 가공하는 방법을 1947년 미공군에 제안하게 되었다. 이것이 NC 발달사에 기록된 역사적인 사실이며 이 Project는 후에 MIT로 넘아가고 1952년에 NC milling machine을 완성시켰다. 그 후, 1955년 Gidding & Lewis사가 최초로 NC 공작기계를 공업화한 제1호기 Numericord를 시장에 내 놓게 되었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.249-254
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• 1992

Hydrostatic Bearings have been applied to ultra high precision machine tools and precision instruments, because of their low friction characteristic, high load carrying capacity and high moving accuracy at all range of speed. In regard to realizing the Hydrostatic Bearing, various restrictors such as capillary, orifice, diaphram valve, spool valve, and etc can be used. However, their stiffness and flexibility are not sufficient in practical use for ultra precision machine tool elements. In this study dynamic equations were derived and the dynamic characteristics were simulated for both orifice and flow control servo valve. Simulation was carried out on the condition that static and sinusoidal dynamic loads were applied to the table of CNC jig Boring machine. The simulation results indicate the improvement of the performance of the Bearing system when flow control servo valve has been used as restrictor of Hydrostatic Bearing.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1760-1769
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• 2007

The cut slope sliding which has been frequently encountered in Pohang area has been reported due to the rapid reduction of shear strength in mudstone after being exposed to the air. Mudstone has characteristics that it has high enough strength and stiffness in a dry condition, but the strength and stiffness decrease in a wet condition with groundwater infiltration. The case study in this paper shows that mudstone which had enough strength in a boring stage has lost the strength after installing PRD steel pipe pile inducing an insufficient bearing capacity, which has been ascertained by the static load test. Test construction has been performed to investigate the most favorable method for increasing a pile bearing capacity in mudstone with various methods such as MSG (Micro Silica Grouting) around the tip and side of a pile, the perimeter grouting combined with Micro pile reinforcement, and concrete filling after tip reinforcing grouting. From the test construction, MSG has been turned out to be the most favorable method for increasing a pile bearing capacity in mudstone, which has been confirmed by the static load test.

• Parasites, Hosts and Diseases
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• v.37 no.1
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• pp.47-49
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• 1999

A case of Pseudoterranova decipiens infection was found in a 43-year-old man by gastroendoscopic examination on August 20, 1996. On August 6, 1996, he visited a local clinic, complaining of epigastric pain two days after eating raw marine fishes. Although the symptoms were relieved soon, endoscopic examination was done for differential diagnosis. A white, live nematode larva was removed from the fundus of the stomach. The larva was $38.3{\times}1.0{\;}mm$ in size and had a cecum reaching to the mid-level of the ventriculus. A lot of transverse striations were regularly arranged on the cuticle of its body surface, but the boring tooth and mucron were not observed at both ends of the worm. The worm was identified as the 4th stage larva of P. decipiens.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.2
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• pp.64-74
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• 1994

The gundrill is capable of machining for having large length to diameter ratio in single pass. The techniques of gundrill and gun boring began developing in the late 18th century with the need for more accurate bores in rifle, cannon, machinery part and marine part etc. The main feature of the gun drilling provides a stabilizing cutting force resultant necessary for self guidance of the drill head. A study of the accuracy and surface finish of holes produced would reveal quite useful information regarding the process. The thesis deals with the experimental results obtained during gun drilling on marine part materials for different machining conditions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.326-331
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• 1999

Grinding technology in morden industry society is focusing on research & development for grinding stone and machining parts for the purpose of high accuracy and high efficiency of products. But, in order to equip the high technology and high accuracy of micro stone which is one of grinding stone, hardly and continuous effort on R&D is required.In this study, honing processing work of 2-cycle engine cylinder for motorcycle which has open hole is practiced so as to clear how borning that is prior step of honing and hone stone make an influence on accuracy of honing. As the result of analyzing the results of experiments, we came to conclusion that we can secure good conditions of honing by controlling and keeping appropriate cycle-time in the stage of boring of prior step of honing.