• Transactions on Electrical and Electronic Materials
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• 제15권1호
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• pp.37-40
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• 2014

A novel memory is reported, in which $Ge_2Sb_2Te_5$ (GST) has been used as a floating gate. The threshold voltage was shifted due to the phase transition of the GST layer, and the hysteretic behavior is opposite to that arising from charge trapping. Finite Element Modeling (FEM) was adapted, and a new simulation program was developed using c-interpreter, in order to analyze the small shift of threshold voltage. The results show that GST undergoes a partial phase transformation during the process of RESET or SET operation. A large $V_{TH}$ shift was observed when the thickness of the GST layer was scaled down from 50 nm to 25 nm. The novel 1 transistor PCM (1TPCM) can achieve a faster write time, maintaining a smaller cell size.

• 보존과학회지
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• 제31권1호
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• pp.65-73
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• 2015

이 연구에서는 국립고궁박물관 소장 태조어진 유소의 상태 조사와 재질 분석을 통해 다회류 유물의 이해를 돕고 보존처리 시 발생할 수 있는 변형률에 대한 안정성 검증 및 효율성을 높이고자 하였다. 유소의 재질 분석 결과 겉실은 견사, 속실은 면사, 금속사의 너비는 $500{\sim}600{\mu}m$,주성분 Copper 55wt%로 확인되었다. 또한 방울술의 형태 교정 시우려되는 변형률을 확인한 결과 1TPCM의 미만의 변형률로 안정성을 검증 하였으며, 절사된 술의 단면을 접합하기 위한 접착제 선정 실험에서는 소맥전분풀이 모든 농도에서 가장 높은 인장력을 도출하여 사용이 가장 용이하다고 판단된다. 이와 같이 유물 분석 및 실험을 토대로 보존처리 과정을 수립하였으며, 그 계획에 따라 보존처리를 실행하여 포장에 이르기 까지 처리를 완료 하였다.

• 한국전기전자재료학회논문지
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• 제27권2호
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• pp.76-80
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• 2014

Dual-gate PCRAM which unify capacitor-less DRAM and NVM using a PCM instead of a typical SONOS flash memory is proposed as 1 transistor. $VO_2$ changes its phase between insulator and metal states by temperature and field. The front-gate and back-gate control NVM and DRAM, respectively. The feasibility of URAM is investigated through simulation using c-interpreter and finite element analysis. Threshold voltage of NVM is 0.5 V that is based on measured results from previous fabricated 1TPCM with $VO_2$. Current sensing margin of DRAM is 3 ${\mu}A$. PCM does not interfere with DRAM in the memory characteristics unlike SONOS NVM. This novel unified dual-gate PCRAM reported in this work has 1 transistor, a low RESET/SET voltage, a fast write/erase time and a small cell so that it could be suitable for future production of URAM.

• Steel and Composite Structures
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• 제32권1호
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• pp.1-19
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• 2019

The aim of the paper is the prediction of the seismic collapse mode of steel storage pallet racks under seismic loads. The attention paid by the researchers on the behaviour of the industrial steel storage pallets racks is increased over the years thanks to their high dead-to-live load ratio. In fact, these structures, generally made by cold-formed thin-walled profiles, present very low structural costs but can support large and expensive loads. The paper presents a prediction of the seismic collapse modes of multi-storey racks. The analysis of the possible collapse modes has been made by an approach based on the kinematic theorem of plastic collapse extended to the second order effects by means of the concept of collapse mechanism equilibrium curve. In this way, the dissipative behaviour of racks is determined with a simpler method than the pushover analysis. Parametric analyses have been performed on 24 racks, differing for the geometric layout and cross-section of the components, designed in according to the EN16618 and EN15512 requirements. The obtained results have highlighted that, in all the considered cases, the global collapse mechanism, that is the safest one, never develops, leading to a dangerous situation that must be avoided to preserve the structure during a seismic event. Although the studied racks follow all the codes prescriptions, the development of a dissipative collapse mechanism is not achieved. In addition, also the variability of load distribution has been considered, reflecting the different pallet positions assumed during the in-service life of the racks, to point out its influence on the collapse mechanism. The information carried out from the paper can be very useful for designers and manufacturers because it allows to better understand the racks behaviour in seismic load condition.