• Proceedings of the KWS Conference
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• 2007.11a
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• pp.39-41
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• 2007

In this study, actual scale welding were conducted at the USC thermal power plant turbine and main steam pipe casting candidate mock up material 9Cr-1.5Mo-CoVNbNB steel(CB2) and 9Cr-0.5Mo-MVNbN steel(P92). And to evaluate the welding process for the actual production, mechanical property testes were conducted for the weld metal. The Mock-up welding condition successfully led to an excellent structural welding joint between casting and pipe material.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.297-302
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• 2004

CFD analysis has been performed to investigate flow behavior in LP exhaust hood of steam turbines and evaluate exhaust loss, which is directly related to the steam turbine performance, in it. Development of the optimum shape of LP exhaust hood has been done with an improved shape of steam guide, which plays a key role in terms of cost as well as performance. The newly developed LP exhaust hood will be applied for a large USC steam turbine having a capacity of 1,000 MW.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.250-252
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• 2005

T/P92 steels are created for using USC boiler tube and header in next generation power plant. SP-Creep test and tensile creep test are performed to characterize creep for local structures of T/P92 steel weldment. The results are shown that P92 steel weldment is clearly superior than that of X20CrMoV121 steel weldment, which is widely used in supercritical power Plant. while fine gram HAZ is most weakest in X20 steel weldment, coarse grain HAZ is most weakest in P92.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.97-104
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• 2018

This paper proposes supplementary control of conventional coordinated control of a power plant which directly affects network frequency. The supplementary control with dynamic matrix control is applied for 1000 MW power plant with ultra-supercritical (USC) once-through boiler. The supplementary control signal is added to the boiler feedforward signal in the existing coordinated control logic. Therefore, it is a very practical structure that can maintain the existing multi-loop control system. This supplementary controller uses the step response model for the power plant system, and on-line optimization is performed at every sampling step. The simulation results demonstrate the effectiveness of the proposed supplementary control in a wide operating range of a practical 1000 MW USC power plant simulator. These results can contribute the stable operation of power system frequency.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.149-151
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• 2004

고효율, 대용량의 친환경적이며 경제적인 발전소건설을 위해 초초임계압(USC: Ultra Super Critical) 석탄화력발전소의 건설이 세계적인 추세이다. 이러한 USC발전소는 효율향상을 위해 증기온도와 압력의 상승, 경제적 운용을 위해 부하변동운전 적용확대가 필수적이다. (중략)

• JOURNAL OF ELECTRICAL WORLD
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• s.428
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• pp.44-49
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• 2012

• Corrosion Science and Technology
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• v.14 no.2
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• pp.76-84
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• 2015

The components in ultra super critical (USC) steam turbine, which is under development for high efficient power generation, are encountering harsher solid particle erosion by iron oxide scales than ones in the existing steam turbines. Therefore, the currently used boride coating will not be able to hold effective protection from particle erosion in USC system and should be replaced by new particle erosion resistant coatings. One of the best protective coatings developed for USC steam turbine parts was found to be vanadium-boride (V-boride) coating which has a hardness of about 3000 HV, much higher than that of boride, 1600~2000 HV. In order to evaluate particle erosion resistance of the various coatings such as V-boride, boride and Cr-carbide coatings at high temperature, particle erosion test equipments were designed and manufactured. In addition, erosion particle velocity was simulated using FLUENT software based on semi-implicity method for pressure linked equations revised (SIMPLER). Based on experimental results of this work, the vanadium-boride coating was found to be superior to others and to be a candidate coating to replace the boride coating.

• Journal of Korean Society of Steel Construction
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• v.21 no.3
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• pp.277-287
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• 2009

The objective of this study was to experimentally investigate the structural behavior of steel plate concrete walls with vertical ribs (SSC walls), to compare the experimental results with the currently applied evaluation equations, and to obtain information that would be useful in the development of design equations for SSC walls. SSC test specimens that were subjected to in plane shear forces and bending moments were fabricated and tested. The experimental results show that the effect of vertical ribs on the structural behavior of SSC walls may be neglected, and that the confinement effect of concrete on the steel plates on both sides of the walls was negligible. The comparison of the experimental results with the evaluation equations showed that the structural behavior of SSC walls under shear control is close to that of the evaluation equations, but that the behavior of SSC walls under larger bending moments is not very close to that of the evaluation equations. The current evaluation equations for USC walls may be applied to the design of SSC walls because the structural walls of nuclear power plants are not subjected to large in plane bending moments.

• Journal of Welding and Joining
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• v.28 no.1
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• pp.41-46
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• 2010

The low alloy-steel material(1.0Cr-0.5Mo, SA213T12), which has widely been used for the waterwall tube in the conventional power plant, do not have enough creep rupture strength for waterwall tubes of the Ultra-supercritical(USC) boilers. According to this reason, the high-strength low alloy-steel(2.25Cr-1.0Mo, SA213T22) has newly been adopted for the waterwall tube in the USC boilers. This paper presents failure analysis on weld-joint of the waterwall tubes in USC boilers. Visual inspections were performed to find out the characteristics of the fracture. Additionally both microscopic characteristics and hardness test were carried out on failed tube samples. Failures seem to happen mainly because the welding process has not been conducted strictly.(preheating, P.W.H.T and so forth). Thus, this paper has the purpose to describe the main cause of the poor welding process and to explain how to prevent similar failures in those weld-joints.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.6
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• pp.337-356
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• 2020

This systematic review focused on the efficacy of topical products in reducing temporomandibular joint disorder (TMD)-associated pain, in comparison to placebo or control interventions. The EMBASE, Web of Science, Cochrane Library, and MEDLINE via PubMed databases were searched for randomized controlled trials (RCTs) using topical interventions in adults diagnosed with TMD. The pain intensity was the primary outcome, and other clinical findings were the secondary outcomes. The risk of bias was evaluated according to the Cochrane's handbook. The search up to February 7, 2020 identified a total of 496 unduplicated references. Nine RCTs with 355 adult patients diagnosed with TMD were included. The meta-analysis did not show a significant reduction in baseline pain intensity in the nonsteroidal anti-inflammatory drug (NSAIDs) group, when compared to the placebo group (P = 0.288). One study demonstrated a statistically significant pain score decrease for Theraflex-TMJ compared to placebo after 10 d of treatment (P = 0.003) and follow-up, 5 d after the last application (P = 0.027). Ping On reduced pain at 4 weeks of application (P < 0.001) but not after 7 d of application (P = 0.136). In one study, cannabidiol (CBD) significantly improved the pain intensity compared to placebo (P < 0.001). However, no differences were found with capsaicin in the two studies (P = 0.465). Evidence was of low quality because the studies were considered as having an unclear or a high risk of bias and a small number of studies were analyzed. The evidence is not sufficient to support the use of topical NSAIDs and capsaicin, and limited evidence was found for Threraflex-TMJ, bee venom, Ping On, and CBD, with only one study reporting for each. Additional studies are recommended to validate these results.