• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.938-941
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• 2001

A tool holder system has been designed and builted to measure cutting forces in diamond turning. This system design includes a 3-component piezo-electric tranducer. Initial experiments with tool holder system included verification of its predicted dynamic characteristics as well as a detailed study of cutting parameters. In this research, tool holder system is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of structure is simulated by MSC/NASTRAN, for the purpose of developing the effective design. In addition, tool holder system is verified by vibration test using accelerometer. Many cutting experiments have been conducted on 6061-T6 aluminum. Tests have involved investigation of velocity effects, and the effects of depth and feedrate on tool force. Cutting velocity has been determined to have negligible effects between 4 and 21㎧.(6) Forces generally increase with increasing depth of cut. Increasing feedrate does not necessarily lead to higher forces. Results suggest that a sample model may not be sufficient to describe the forces produced in the diamond turning process.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.2019-2026
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• 2003

Spray and combustion characteristics of a dump-type ram-combustor equipped with a V-gutter flame holder were experimentally investigated. Spray penetrations with a change in airstream velocity, air stream temperature, and dynamic pressure ratio were measured to clarify the spray characteristics of a liquid jet injected into the subsonic vitiated airstream, which maintains a highly uniform velocity and temperature. An empirical equation was modified from Inamura's equation to compensate for experimental conditions. In the case of insufficient penetration, the flame in the ram-combustor was unstable, and vice versus in the case of sufficient penetration. When the flame holder was not equipped, the temperature at the center of the ram-combustor had a tendency to decrease due to the low penetration and insufficient mixing. Therefore, the temperature distribution was slanted to the low wall of the ram-combustor. These trends gradually disappeared as the length of the combustor became longer and the flame holder was equipped. Combustion efficiency increased when the length of the combustor was long and the flame holder was equipped. Especially, the effect of the flame holder was more dominant than that of the combustor length in light of combustion efficiency.

• Radiation Oncology Journal
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• 제19권3호
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• pp.293-299
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• 2001

목적 : 생체 내 선량측정은 TLD에 의한 것이 전반적인 선량측정 확인 방법 중에 가장 효과적인 방법이긴 하지만 LiF TLD의 경우 생체 내에 사용하고자 할 때 가장 큰 문제점은 LiF가 갖고 있는 독성이다. 본 연구에서는 LiF TLD 이용하여 생체 내 선량측정에 유용한 새로운 방법를 개발하고자 한다. 대상 및 방법 : 이를 위하여 LiF TLD를 넣을 수 있는 테프론 상자(이후 TLD홀더라 칭함)를 설계 제작하였다. TLD홀더의 외형적 크기는 $4\times4\times1\;mm^2$ 이다. TLD을 TLD홀더에 넣어서 방사선량을 측정할 경우 TLD홀더가 TLD 반응값에 미치는 영향을 알아보기 위해 먼저 TLD홀더에 넣은 TLD 반응값의 방사선량에 대한 선형성을 측정하였다. TLD 홀더와 같은 크기의 흠을 가진 고체 팬텀 내에 TLD홀더를 넣어서 치료용 가속기로부터 나오는 10 MV의 방사선을 조사하여서 반응값을 측정하였다. 또한 방사선 치료시 선량 계산을 위해 필요로 하는 선량계수의 TLD홀더에 의한 방사선량 변화를 측정하기 위하여 PDD와 고체 팬텀의 두께 변화에 따른 TMR을 구하였다. 결과 : 실험 결과 본 연구에서 개발한 TLD홀더에 넣은 TLD 선량계의 경우 다양한 측정 조건에서 구한 TLD홀더에 넣은 TLD 선량계의 반응값과 TLD홀더에 넣지 않은 경우의 반응값이 거의 같은 값을 갖는 것으로 나타났다. 결론 : TLD홀더가 TLD 반응값에 그다지 영향을 미치지 않으므로 TLD홀더에 넣은 TLD 선량계가 생체 내 선량측정에 적합한 것으로 판명되었다.

• 한국공간구조학회논문집
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• 제20권4호
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• pp.53-62
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• 2020

This study examines the optimum shape of a trolley, the driving device of the retractable membrane roof. The closed-type trolley was determined as the model of the study, and a trolley composed of cylindrical-shaped inner and outer holders was selected as the basic model. Based on this model, a cylindrical-based optimal trolley model was proposed. In the basic trolley model, steel was used for the outer holder, and steel, titanium, and aluminum were used for the inner holder. In each case, the most economical shape for the external load of the basic model was newly proposed through the topology optimization process, and the finite element analysis results of the proposed model were compared to define the durability and economics. Here, topology optimization analysis and finite element analysis used the commercial software ANSYS. As a result of optimization, the volume of the outer holder of the trolley was reduced by 58.2% and the volume of the inner holder was reduced by 25.0% compared to the basic model. In the case of stress, a stress increase of 43.2 to 79.2% occurred depending on the material of the inner holder, but it was found to be significantly lower than the yield strength, thereby ensuring safety.

• 시멘트
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• 통권76호
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• pp.57-63
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• 1979

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2005년도 춘계 학술발표대회 논문집
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• pp.30-31
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• 2005

• 무역상무연구
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• 제15권
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• pp.169-209
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• 2001

As a domain name can be registered simply by filing an application for registration, disputes over the domain name between the holder of domain name and the holder of trademark increased. Since the holder of trademark who was late for registering domain name is willing to pay for the return of domain name, cybersquatters increased. Cybersqatters are not genuine users of the Internet. This article is to compare the construction of law by American Courts and by Korean Courts and to assert the creation of the law similar to the law of US as to anti-cybersqatting. American Courts applied the Trademark Act and the Anti-Dilution Act to resolve the disputes over domain name. To apply the Trademark Act, the Court required the plaintiffs to prove that the goods or the services expressed by the domain name should be identical or similar to the goods or the services represented by the trademark. However, there were many cases where the holder of domain name used it for the goods or the services irrelevant to those of the holder of trademark. Also, the Anti-Dilution Act could not successfully protect the holder of trademark from cybersquatters because it required that the trademark should be famous or distinctive. As a result, the US promulgated a new law which is designed to prohibit cybersquatters from being free of sanction by the existing laws. Korea Courts applied the Trademark Act and the Unfair Competition Prohibition Act to the cases disputing domain name. Likewise in the US, Korean Courts must cope with the issue of identity of the goods or the services, and the famousness or distinctiveness of trademark. The Courts hesitate to give a winning judgement to the holder of trademark simply because the domain name of alleged violator confused the trademark. Some scholars advocate the broadening of construction of the Unfair Competition Prohibition Act to illegalize cybersquatting but it is beyond the meaning of the law. Accordingly, it is a time to make a law similar to the Anti-Cybersquatting Act of the US. The law must be a fair and reasonable compromise to resolve the collision between system of registration of domain name and the system of registration of trademark. Some commentators advocate that the registration of domain name should be examined just as the one of trademark and to facilitate it, the Patent and Trademark Office should have jurisdiction of registration of domain name. But it abandons the distinction of domain name and trademark and results in obstructing e-commerce. By adopting the Anti-Cybersqatting Act, we can prohibit it. In other cases, we get a reasonable adjustment between the holder of domain name and the holder of trademark through the Trademark Act and the Unfair Competition Prohibition Act.

• Korean Journal of Acupuncture
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• 제25권2호
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• pp.143-158
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• 2008

Objectives : The purpose of this study is to observe the anti-oxidative effects of electroacupuncture at GB34(Yangreungcheon) in rats. Methods : The authors performed several experimental items including measurements of body weight, relative liver weight, levels of albumin, total bilirubin, LDL-cholesterol, LDH, GOT and GPT in blood serum, levels of SOD, glutathione, catalase, NO and MDA in liver, and histological analysis of liver. The conclusions are as follows. Results : 1. In the GB34-EA group, liver index was lower than those of the control group and the holder group. 2. In the GB34-EA group, the levels of albumin and total bilirubin in serum were increased significantly compared to those of the control and the holder group. LDL-cholesterol level was decreased significantly compared to those of the control group and the holder group. 3. In the GB34-EA group, liver SOD, glutathione, catalase activity were increased, and NO concentration in liver was decreased significantly compared to those of control and the holder group. 4. In the GB34-EA group, the density of liver tissue was more similarly maintained to that of the normal group compared to those of the control group, holder group and sham-EA group. Conclusions : These results suggest that electroacupuncture at GB34 may have an antioxidant effect in rat.

• 한국생산제조학회지
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• 제25권1호
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• pp.1-6
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• 2016

Micromanufacturing is a useful system for reducing energy consumption. For micromanufacturing, tool clamping and workpiece clamping are important components to realize the machining process. Therefore, a shape memory alloy (SMA) ring type tool holder is developed. In addition, this holder needs cooling and heating processes to execute the tool clamping process. This study suggests a cooling/heating device based on peltier elements. The device will be applied to the heating/cooling process of an automatic tool changer (ATC) for the SMA tool holder. This study introduces the configuration and operating principle of the proposed ATC system. The description and prototype evaluation of this system were given. Plastic bolt and aluminum block were selected to enhance the cooling performance, and the installed tool was changed in 17 s during the experiments.

• 대한기계학회논문집A
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• 제33권11호
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• pp.1187-1194
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• 2009

During the last decade, possibility of flaw occurrences has been rapidly increased world-widely as the increase of operating times of petro-chemical facilities. For instance, from a recent in-service inspection, three different sized surface cracks were detected in welding parts of a spherical oxygen holder in Korea. While API579 code provides corresponding engineering assessment procedures to determine crack driving forces, in the present work, numerical analyses are carried out for the cracked oxygen holder to investigate effects of complex geometry, analysis model and residual stress. With regard to the detailed finite element analysis, stress intensity factors are determined from both the full three-dimensional model and equivalent plate model. Also, as an alternative, stress intensity factors are calculated for equivalent plate model by employing the noted influence stress function technique. Finally, parametric structural integrity evaluation of the cracked oxygen holder is conducted in use of failure assessment diagram method, J/T method and DPFAD method. Effects of the geometry and so forth are examined and key findings from the simulations are fully discussed, which enables to determine practical safety margins of spherical components containing a defect.