Abstract
High-contrast instruments are required for direct imaging of faint exoplanets around bright host stars. In high-contrast instruments, a wave front control system is needed to generate a dark ...hole by suppressing residual stellar speckles. However, the achievable contrast is limited by the phase quantization error (i.e., finite phase resolution) of wave front control devices, such as deformable mirrors or spatial light modulators. In this paper, we propose a halftone method for wave front control to improve the contrast using a wave front control device with quantized phase modulation. In a numerical simulation, the contrast was improved from 1.4 × 10
−9
to 3.8 × 10
−10
by halftone wave front control. In addition, we performed a laboratory demonstration in which a spatial light modulator was used for wave front control, and the contrast was improved from 2.2 × 10
−7
to 6.0 × 10
−8
for a phase resolution of 2
π
/256.
Static charge removal with IPA solution Ohmi, T.; Sudoh, S.; Mishima, H.
IEEE transactions on semiconductor manufacturing,
11/1994, Letnik:
7, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Due to the an increase in pattern densities and wafer diameters, it is extremely difficult for wet chemical processing to perform complete cleaning, rinsing and drying for highly rugged surface of ...very fine pattern ULSI devices. IPA Vapor Drying is a widely used drying method in semiconductor manufacturing. As IPA has low surface tension and very high solubility to water, it is suitable for IPA vapor process to perfectly eliminate contamination of the wafer surface. This drying system also has an ability to eliminate static charge and can essentially achieve the high quality of the surface cleanliness. Therefore, the mechanism of static charge removal was studied using a quantitative method for the direct measurement of static charge.< >
Single-ion conducting liquid electrolytes are key to achieving rapid charge/discharge in Li secondary batteries. The Li+ transference (or transport) numbers are the defining properties of such ...electrolytes and have been discussed in the framework of concentrated solution theories. However, the connection between macroscopic transference and microscopic ion dynamics remains unclear. Molecular dynamics simulations were performed to obtain direct information regarding the microscopic behaviors in highly concentrated electrolytes, and the relationships between these behaviors and the transference number were determined under anion-blocking conditions. Various solvents with different donor numbers (DNs) were used along with a Li salt of the weakly Lewis basic bis(fluorosulfonyl)amide anion for electrolyte preparation. Favorable ordered Li+ structuring and a continuous Li+ conduction pathway were observed for the fluoroethylene carbonate-based electrolyte due to its low DN. The properties were less pronounced at higher DNs, e.g., for the dimethyl sulfoxide-based electrolyte. The τLi-solventlife/τdipolerelax ratio was introduced as a factor for ion dynamics, and the two mechanisms of ion transport were considered an exchange mechanism (τLi-solventlife/τdipolerelax < 1) and a vehicle mechanism (translational motion of solvated Li+) (τLi-solventlife/τdipolerelax ≥ 1). Vehicle-type transport was dominant with high DNs, while exchangeable transport was preferable at lower DNs. These findings should aid the further selection of solvents and Li salts to prepare single-ion conducting electrolytes.
Localized high-concentration electrolytes (LHCEs), which are mixtures of highly concentrated electrolytes (HCEs) and non-coordinating diluents, have attracted significant interest as promising liquid ...electrolytes for next-generation Li secondary batteries, owing to their various beneficial properties both in the bulk and at the electrode/electrolyte interface. We previously reported that the large Li+-ion transference number in sulfolane (SL)-based HCEs, attributed to the unique exchange/hopping-like Li+-ion conduction, decreased upon dilution with the non-coordinating hydrofluoroether (HFE) despite the retention of the local Li+-ion coordination structure. Therefore, in this study, we investigated the effects of HFE dilution on the Li+ transference number and the solution structure of SL-based LHCEs via the analysis of dynamic ion correlations and molecular dynamics simulations. The addition of HFE caused nano-segregation in the SL-based LHCEs to afford polar and nonpolar domains and fragmentation of the polar ion-conducting pathway into smaller clusters with increasing HFE content. Analysis of the dynamic ion correlations revealed that the anti-correlated Li+–Li+ motions were more pronounced upon HFE addition, suggesting that the Li+ exchange/hopping conduction is obstructed by the non-ion-conducting HFE-rich domains. Thus, the HFE addition affects the entire solution structure and ion transport without significantly affecting the local Li+-ion coordination structure. Further studies on ion transport in LHCEs would help obtain a design principle for liquid electrolytes with high ionic conductivity and large Li+-ion transference numbers.
Here, we report the use of molecular dynamics simulations with a polarizable force field to investigate Li-ion dynamics in sulfolane (SL)-based electrolytes. In SL-based highly concentrated ...electrolytes (HCEs) (e.g., SL/Li = 2:1), Li displays faster translational motion than other components, which should be related to the structural and dynamical properties of SL. In HCEs, a transient conduction network that penetrated the simulation system was always observed. Rapid (<1 ns) Li-ion hopping between adjacent coordination sites was observed throughout the network. Additionally, SLs rotated in the same timeframe without disrupting the conduction network. This rotation is believed to promote the hopping diffusion in the network. This was followed by a rotational relaxation of the SL dipole axis around the non-polar cyclohydrocarbon segment of SL (∼3.3 ns), which involves a reorganization of the network structure and an enhancement of the translational motion of the coordinating Li ions. The observed lifetime of Li–SL coordination was longer (>11 ns). Hence, it was concluded that the faster Li translational motion was obtained due to the faster rotational relaxation time of SL rather than the lifetime of Li–SL binding. The faster rotation of SL is related to its amphiphilic molecular structure with compact non-polar segments. Transport properties, such as the Onsager transport coefficients, ionic conductivity, and transference number under anion-blocking conditions, were also analyzed to characterize the features of the SL-based electrolyte.
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