• Nuclear Engineering and Technology
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• 제30권5호
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• pp.424-434
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• 1998

RELAP5/Mod3.1 code was assessed with the semiscale experiment S-NC-3, and S-NC-4, which simulated the two-phase natural circulation and reflux condensation for the SBLOCA of PWR, respectively . Test S-NC-3 and S-NC-4 calculation results showed that RELAP5/Mod3.1 quite well describes the influence of steam generator secondary side heat transfer degradation on both two-phase natural circulation and reflux condensation. A comparison between the calculated and measured two-phase mass flow rate in test S-NC-3 shows good agreement for primary mass inventory more than 92%. And RELAP5/Mod3.1 have a good mass flow rate prediction capability for the transient such as S-NC-4 except some flow oscillations. The reflux flow rate for S-NC-4 test is under predicted, and the overall results verify that the correct prediction of the reduced liquid level appears to be required for the correct calculation of the overall phenomena.

• 설비공학논문집
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• 제14권10호
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• pp.844-853
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• 2002

A dynamic model which simulates the coupled heat and mass transfer within a vertical tube absorber was developed. The liquid film is a binary mixture of two components, and both of these components are present in the vapor phase. The pressure, concentration, temperature and mass flow rate of the vapor are obtained by assuming that the pressure is uniform within an absorber. The model was applied to an absorber for an ammonia/water absorption refrigerator. The transient behaviors of the pressure, the outlet temperature and the concentration of the solution and the cooling water outlet temperature on a step change at the absorber inlet of the cooling water temperature, the vapor mass flow rate and the concentration of the solution were shown.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.617-624
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• 1997

This Paper Presents an effective and simple procedure for the simulation of the motion of the solid-liquid interfacial boundary and the transient temperature field during phase change process. To accomplish this purpose, an iterative implicit solution algorithm has been developed by employing the dual reciprocity boundary element method. The dual reciprocity boundary element approach provided in this paper is much simpler than the usual boundary element method applying a reciprocity principle and an available technique for dealing with domain integral of boundary element formulation simultaneously. The effectiveness of the present analysis method have been illustrated through comparisons of the calculation results of an example with its semi-analytical or other numerical solutions where available.

• 마이크로전자및패키징학회지
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• 제19권1호
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• pp.17-24
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• 2012

Recently, flip chip interconnection has been increasingly used in microelectronic assemblies. The common Flip chip interconnection is formed by reflow of the solder bumps. Lead-Tin solders and Tin-based solders are most widely used for the solder bump materials. However, the flip chip interconnection using these solder materials cannot be applied to temperature-sensitive components since solder reflow is performed at relatively high temperature. Therefore the development of low temperature bonding technologies is required in these applications. A few bonding techniques at low temperature of $150^{\circ}C$ or below have been reported. They include the reflow soldering using low melting point solder bumps, the transient liquid phase bonding by inter-diffusion between two solders, and the bonding using low temperature curable adhesive. This paper reviews various low temperature bonding methods.

• 마이크로전자및패키징학회지
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• 제26권4호
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• pp.7-13
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• 2019

Power module is getting attention from electronic industries such as solar cell, battery and electric vehicles. Transient liquid phase (TLP) boding, sintering with Ag and Cu powders and wire bonding are applied to power module packaging. Sintering is a popular process but it has some disadvantages such as high cost, complex procedures and long bonding time. Meanwhile, TLP bonding has lower bonding temperature, cost effectiveness and less porosity. However, it also needs to improve ductility of the intermetallic compounds (IMCs) at the joint. Wire boding is also an important interconnection process between semiconductor chip and metal lead for direct bonded copper (DBC). In this study, TLP bonding using Sn-based solders and wire bonding process for power electronics packaging are described.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.555-556
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• 2006

The study examines hardness pattern of SH737-2Cu-.9C samples transient liquid phase sintered at different temperatures viz. $1120^{\circ}C$, $1180^{\circ}C$ and $1250^{\circ}C$, heat treated by various methods and then tempered at different temperatures. Sintered samples were characterized for density and densification parameter, and austenitized at $900^{\circ}C$, subsequently cooled by four different methods viz. annealing, normalizing, oil and brine quenching. Hardness pattern was found minimum for air cooled and maximum for brine quenched, and samples sintered at $1250^{\circ}C$ had relatively higher hardness. The O.Q and B.Q samples were then tempered at $200^{\circ}C$, $400^{\circ}C$, $600^{\circ}C$ and $700^{\circ}C$. Hardness pattern typically showed secondary hardness taking place, with maximum around $600^{\circ}C$.

• 한국분말재료학회지
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• 제17권6호
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• pp.489-493
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• 2010

Nickel-based and iron-based alloys have been developed and commercialized for a wide range of high performance applications at severely corrosive and high temperature environment. This alloy foam has an outstanding performance which is predestinated for diesel particulate filters, heat exchangers, and catalyst support, noise absorbers, battery, fuel cell, and flame distributers in burners in chemical and automotive industry. Production of alloy foam starts from high-tech coating technology and heat treatment of transient liquid-phase sintering in the high temperature. These technology allow for preparation of a wide variety of foam compositions such as Ni, Cr, Al, Fe on various pore size of pure nickel foam or iron foam in order for tailoring material properties to a specific application.

• Nuclear Engineering and Technology
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• 제35권4호
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• pp.261-273
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• 2003

The characteristics of the recirculation operation of LMR which are different from the conventional plants such as PWR and fossil fuel plants were investigated using a computer code TSGS developed in this study. For simulating the transient behavior of the steam generation system, a water level control algorithm utilizing digital control hardware features was introduced. By investigation, the function of the recirculation operation was defined, the major features of the operation were found. Also good performance of the level control algorithm was confirmed.

• Journal of Welding and Joining
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• 제7권2호
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• pp.12-24
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• 1989

천이액상확산접합법은 접합계면에 일시적으로 액상이 형성되기 때문에, 고상확산접합법과 비교 하여 비교적 쉽게 금속결합을 이룰 수 있을 뿐만 아니라, 정밀하게 표면을 가공할 필요가 없으 며, 접합압력이 거의 필요 없다는 것이 잇점이라고 할 수 있다. 도한, 접합온도에서 등온응고되 기 때문에, 브레이징법과 비교하여 접합계면에 취약한 금속간화합물(Metallic Compound)이 생 성되지 않으므로, 기계적성질 및 내식성이 우수한 접합이음부를 얻을 수 있다는 잇점이 있다. 따라서, 본 접합법은 원리적으로 모재(Base Metal)와 거의 같은 정도의 물리적, 화학적, 기계적 성질을 갖는 접합이음부(Joint or Bonded Interlayer)를 얻을 수 있는 접합법이라고 생각되어진 다. 본 해설에서는 천이액상확산접합법의 기본원리, 접합기구, 접합인자 및 실용된 예에 대해서 서술하고자 한다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.15-18
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• 2008

본 연구에서는 터보펌프 조립체-가스발생기 연계시험 중 개회로 시험에 대한 시동 특성을 분석하였고 수치적으로 해석하였다. 시험에서 터빈의 시동 및 구동은 수소 기체로 수행하였고 그에 따른 가스발생기 점화 및 연소압의 발달을 살펴보았고 해석도 동일한 조건으로 수행하여 결과를 비교하였다. 회전수의 발달 특성은 시험과 잘 일치하는 것을 볼 수 있었고 가스발생기 연소압 발달 특성의 경우 정성적인 기울기가 일치하는 것을 볼 수 있었다.