RADIAL ROTATING ERROR MEASURING METHOD OF ROTATING SHAFT

본 발명은 유사한 피치를 갖는 두 개의 격자를 이용하여 회전축의 회전오차를 정확하게 측정할 수 있도록 개선한 회전축의 반경방향 회전오차측정방법에 관한 것으로, 기준구 또는 기준원통과 변위센서를 이용하는 종래의 측정방법은 기준의 형상오차가 회전오차가 함께 측정되고 기준구의 질량이 회전축의 질량에 더해지는 등 회전축의 동적 운동특성이 변하게 되어 정확한 회전오차를 측정할 수 없게 되고 기준과 센서의 거리가 가까워야 하므로 가공중에는 측정이 어렵게 되는 등의 문제가 있었던 바, 회전축의 끝단에 간격이 일정한 동심원들로 구성된 회전격자를 부착한 후 회전격자의 간격보다 조금 큰 등간격의 동심원으로 이루어지는 고정격자를 통해 회전격자를 관찰하여 두 격자 사이에 나타나는 간섭무늬의 변화를 이용하여 회전축의 회전정도를 측정하는 것을 특징으로 하는 본 발명에 의하면 격자자체의 오차가 적어 회전축의 회전정도를 정확하게 측정할 수 있게 될 뿐 아니라 광학계를 구성하기에 따라서는 가공중에 회전정도를 측정하는 것도 가능하게 된다

Measurement of Radial Error Motions of a Rotating Spindle by Moire Topography

Moire principles are applied to the measurement of the spindle radial error motion. As opposed to conventional techniques, no master cylinder or ball is needed in the measurement so that the offset and out-of-roundness errors of the master can be inherently eliminated. Two periodic circular gratings are used, one is made on the spindle and the other is held stationary on the reference frame. When the two gratings are seen superimposed during spindle rotation, an interference fringe pattern is observed from which the information on the eccentricity between the two gratings can be extracted with high precision. The optical design and fringe analysis techniques of a prototype measurement system are described in detail with exemplary measurement results

Measurement of radial motion of spindle by moire phenomenon

학위논문(박사) - 한국과학기술원 : 정밀공학과, 1994.2, [ ix, 92 p. ]한국과학기술원 : 정밀공학과

A digital measurement system for spindle accuracy

학위논문(석사) - 한국과학기술원 : 생산공학과, 1988.2, [ iii, 63 p. ]한국과학기술원 : 생산공학과

THE CAPACITORLESS DRAM AND METHOD FOR FABRICATING THEREOF

본 발명은 커패시터리스 디램(capacitorless DRAM) 및 그 제조방법을 개시한다. 본 발명에 따른 커패시터리스 디램은 기판상에 연속하여 형성된 소스, 채널 및 드레인, 상기 채널상에 형성된 게이트 절연막, 상기 게이트 절연막상에 형성된 게이트, 및 상기 채널 내부에 형성된 게르마늄층 또는 게르마늄점을 포함한다. 본 발명에 따른 커패시터리스 디램은 실리콘 기판에 형성된 게르마늄의 연속적인 층 혹은 불연속적인 점이 정공 배리어를(hole barrier) 변화 시켜서 정공(hole)을 효과적으로 모을 수 있기 때문에 정공저장능력이 향상된다

Ensemble Design of Electrode-Electrolyte Interfaces: Toward High-Performance Thin-Film All-Solid-State Li-Metal Batteries

In accordance with the fourth industrial revolution (4IR), thin-film all-solid-state batteries (TF-ASSBs) are being revived as the most promising energy source to power small electronic devices. However, current TF-ASSBs still suffer from the perpetual necessity of high-performance battery components. While every component, a series of a TF solid electrolyte (i.e., lithium phosphorus oxynitride (LiPON)) and electrodes (cathode and Li metal anode), has been considered vital, the lack of understanding of and ability to ameliorate the cathode (or anode)-electrolyte interface (CEI) (or AEI) has impeded the development of TF-ASSBs. In this work, we suggest an ensemble design of TF-ASSBs using LiPON (500 nm), an amorphous TF-V2O5-x cathode with oxygen vacancies (O-vacancy), a thin evaporated Li anode (evp-Li) with a thickness of 1 mu m, and an artificial ultrathin Al2O3 layer between evp-Li and LiPON. Well-defined O-vacancy sites, such as O(II)(vacancy) and O(III)(vacancy), in amorphous TF-V2O5-x not only allow isotropic Li+ diffusion at the CEI but also enhance both the ionic and electronic conductivities. For the AEI, we employed protective Al2O3, which was specially sputtered using the facing target sputtering (FTS) method to form a homogeneous layer without damage from plasma. In regard to the contact with evp-Li, interfacial stability, electrochemical impedance, and battery performance, the nanometric Al2O3 layers (1 nm) were optimized at different temperatures (40, 60, and 80 degrees C). The TF-ASSB cell containing Al2O3 (1 nm) delivers a high specific capacity of 474.01 mAh cm(-3) under 60 degrees C at 2 C for the 400th cycle, and it achieves a long lifespan as well as ultrafast rate capability levels, even at 100 C; these results were comparable to those of TF Li-ion battery cells using a liquid electrolyte. We demonstrated the reaction mechanism at the AEI utilizing time-of-flight secondary ion mass spectrometry (TOF-SIMS) and molecular dynamics (MD) simulations for a better understanding. Our design provides a signpost for future research on the rational structure of TF-LIBs

Ferromagnetism in β-Ag2Se topological semimetal

High-temperature ferromagnetism in materials composed of non-magnetic constituents is one of the most intriguing aspects in condensed matter physics as well as materials science. Beyond oxide compounds where the ferromagnetism is mainly induced by dilute magnetic dopants, a variety of unusual ferromag- netic materials, mostly fabricated artificially to control the magnetic and electronic properties, have been investigated for spintronic device applications. The unexpected ferromagnetism, attributed to strain and structural defects or proximity and interfacial effects, is now extended to quantum materials, despite prevailing controversy on its physical origin. Recently, the ferromagnetism observed in topological mate- rials with high mobility arising from the linear energy dispersion invokes new interest in the field of spintronics. Here, we report experimental verification of peculiar high-temperature ferromagnetism in β- Ag2Se topological semimetal, composed of non-magnetic constituents. We have fabricated stoichiometric Ag2Se (S-Ag2Se) and Ag-vacant Ag2Se (V-Ag2Se) samples. Contrary to non-magnetic behavior of S-Ag2Se, V- Ag2Se shows distinct ferromagnetic response up to room temperatures. First-principles calculations de- monstrate that the ferromagnetic ordering occurs only in V-Ag2Se if there is finite Hubbard U, which can be explained by self-trapped magnetic polaron model with strong p-d hybridization. High-temperature fer- romagnetism, especially in topological materials, allows exploring a significant new direction in material engineering for spintronic applications