A Study on Hermetic Glass Sealing Using a Modified Direct Bonding Method

AbstractThis paper presents the process and experimental results about the improved initial bonding between #7740 glass and silicon wafers. We employed a modified initial bonding procedure, called by water-enhanced direct bonding(WDB) technique, and could obtain large initially-bonded area(≥ 95% of the whole wafer area) at room temperature and high interface energy (≥ 2,000 erg/cm2) through 250 °C post-annealing even though the glass wafer had high surface roughness. The main factors contributing to the wider bonded area and higher interface energy in the developed WDB process could be inferred the increase of chemical species (oxygen and hydroxyl groups) responsible for initial hydrogen bonding and conversion from hydroxyl bonds to siloxane bonds in the temperature range between room temperature and 250 °C.

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The synthesis of bayberry-like mesoporous TiO2 microspheres by a kinetics-controlled method and their hydrophilic films

CrystEngComm ◽

10.1039/c9ce01824g ◽

2020 ◽

Vol 22 (5) ◽

pp. 969-978 ◽

Cited By ~ 3

Author(s):

Li Li ◽

Liang Wang ◽

Xinhong Chen ◽

Changyuan Tao ◽

Jun Du ◽

...

Keyword(s):

Surface Roughness ◽

High Surface ◽

Mesoporous Tio2 ◽

High Density ◽

Hydroxyl Groups ◽

Surface Hydroxyl ◽

High Surface Roughness ◽

Surface Hydroxyl Groups ◽

Tio2 Microspheres

Bayberry-like mesoporous TiO2 hydrophilic films with high surface roughness and high density of surface hydroxyl groups.

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Influence of Processing Factors on the Surface Properties of Zirconia Coatings Fabricated by Room Temperature Spray Process

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17609 ◽

2020 ◽

Vol 20 (7) ◽

pp. 4152-4157

Author(s):

Jeong Jun Kim ◽

Jong Kook Lee

Keyword(s):

Surface Roughness ◽

Particle Size ◽

Surface Properties ◽

Room Temperature ◽

Coating Layer ◽

High Surface ◽

Phase Changes ◽

Deposition Cycle ◽

Implant Surface ◽

Processing Factors

Highly roughened surfaces on dental implants enhance the bone-bonding ability and in vivo cell adhesion on the implant surface. In this study, zirconia substrates were coated by powder coating using room temperature spray processing to improve their surface properties. Processing factors (particle size of the starting powder, number of repetitions of the deposition cycle, and spraying distance) were controlled to form a dense coating layer with high surface roughness on the zirconia substrate. Starting zirconia powders for coating were heat-treated at high temperature to control the particle size and kinetic energy. The coating layer fabricated from starting powder with a particle size of about 1.52 μm shows a homogeneous and dense microstructure, and it has a maximum surface roughness about 0.37 μm. The surface roughness of the film coatings increased with the number of times that the deposition cycle was repeated. No phase changes between the starting powder and the coating layer were observed, and all of the materials show identical tetragonal phases.

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Changes in Bond Strength and Topography for Y-TZP Etched with Hydrofluoric Acid Depending on Concentration and Temperature Conditions

Medicina ◽

10.3390/medicina56110568 ◽

2020 ◽

Vol 56 (11) ◽

pp. 568

Author(s):

Hyo-Eun Kim ◽

Myung-Jin Lim ◽

Mi-Kyung Yu ◽

Kwang-Won Lee

Keyword(s):

Surface Roughness ◽

Bond Strength ◽

Hydrofluoric Acid ◽

Room Temperature ◽

High Surface ◽

Tetragonal Zirconia ◽

Resin Cement ◽

Grain Structure ◽

Temperature Conditions ◽

Significant Difference

Background and objectives: This study aimed to investigate the change in bond strength between resin cement and tetragonal zirconia polycrystalline stabilized with 3 to 8 mol% yttrium oxide (Y-TZP) and observe the topographical change of the Y-TZP surface when etched with hydrofluoric acid (HF) solution under different concentration and temperature conditions. Materials and Methods: Non-etched sintered Y-TZP specimens under two different temperature conditions (room temperature and 70–80 °C, respectively), were used as a control, while experimental groups were etched with 5%, 10%, 20%, and 40% HF solutions for 10 min. After zirconia primer and MDP-containing resin cement were applied to the Y-TZP surface, the shear bond strength (SBS) of each experimental group was measured. Results: Under room temperature conditions, the highest SBS value was measured in the 40% HF etching group, representing a significant deviation from the other groups (p < 0.05). In the 70–80 °C tests, the 40% HF etching group also had the highest SBS value, but there was no significant difference when compared to the 20% HF etching group (p > 0.05). From SEM and AFM observations, the HF solution increasingly dissolved the Y-TZP surface grain structure as the concentration and application temperature rose, resulting in high surface roughness and irregularities. Conclusions: Pretreating with either 20% HF solution at 70–80 °C or 40% HF solution at room temperature and 70–80 °C effectively acid etched the Y-TZP surface, resulting in more surface roughness and irregularities. Accounting for the concentration and temperature conditions of the HF solution, using 40% HF solution at room temperature will result in improvements in adhesion between resin cement and Y-TZP.

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Room-Temperature Chemical Synthesis of C2

10.26434/chemrxiv.8009633 ◽

2019 ◽

Author(s):

Kazunori Miyamoto ◽

Shodai Narita ◽

Yui Masumoto ◽

Takahiro Hashishin ◽

Mutsumi Kimura ◽

...

Keyword(s):

Chemical Synthesis ◽

Ground State ◽

Room Temperature ◽

Chemical Species ◽

Quadruple Bond ◽

Photon Excitation ◽

Physical Energy ◽

Theoretical Predictions ◽

Carbon Arc ◽

Inherent Nature

Diatomic carbon (C2) is historically an elusive chemical species. It has long been believed that the generation of C2 requires extremely high “physical” energy, such as an electric carbon arc or multiple photon excitation, and so it has been the general consensus that the inherent nature of C2 in the ground state is experimentally inaccessible. Here, we present the first “chemical” synthesis of C2 in a flask at room temperature or below, providing the first experimental evidence to support theoretical predictions that (1) C2 has a singlet biradical character with a quadruple bond, thus settling a long-standing controversy between experimental and theoretical chemists, and that (2) C2 serves as a molecular element in the formation of sp2-carbon allotropes such as graphite, carbon nanotubes and C60.

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Understanding Sulfur Redox Mechanisms in Different Electrolytes for Room-Temperature Na–S Batteries

Nano-Micro Letters ◽

10.1007/s40820-021-00648-w ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Hanwen Liu ◽

Wei-Hong Lai ◽

Qiuran Yang ◽

Yaojie Lei ◽

Can Wu ◽

...

Keyword(s):

Room Temperature ◽

High Surface ◽

Reversible Capacity ◽

High Loading ◽

Side Reactions ◽

Liquid Sulfur ◽

Shuttle Effect ◽

Loading Ratio ◽

Solid Liquid ◽

Sulfur Cathodes

Abstract This work reports influence of two different electrolytes, carbonate ester and ether electrolytes, on the sulfur redox reactions in room-temperature Na–S batteries. Two sulfur cathodes with different S loading ratio and status are investigated. A sulfur-rich composite with most sulfur dispersed on the surface of a carbon host can realize a high loading ratio (72% S). In contrast, a confined sulfur sample can encapsulate S into the pores of the carbon host with a low loading ratio (44% S). In carbonate ester electrolyte, only the sulfur trapped in porous structures is active via ‘solid–solid’ behavior during cycling. The S cathode with high surface sulfur shows poor reversible capacity because of the severe side reactions between the surface polysulfides and the carbonate ester solvents. To improve the capacity of the sulfur-rich cathode, ether electrolyte with NaNO3 additive is explored to realize a ‘solid–liquid’ sulfur redox process and confine the shuttle effect of the dissolved polysulfides. As a result, the sulfur-rich cathode achieved high reversible capacity (483 mAh g−1), corresponding to a specific energy of 362 Wh kg−1 after 200 cycles, shedding light on the use of ether electrolyte for high-loading sulfur cathode.

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Osseointegrating and phase-oriented micro-arc-oxidized titanium dioxide bone implants

Journal of Applied Biomaterials & Functional Materials ◽

10.1177/22808000211006878 ◽

2021 ◽

Vol 19 ◽

pp. 228080002110068

Author(s):

Hsien-Te Chen ◽

Hsin-I Lin ◽

Chi-Jen Chung ◽

Chih-Hsin Tang ◽

Ju-Liang He

Keyword(s):

Titanium Dioxide ◽

High Surface ◽

Cell Activity ◽

Active Surface ◽

Rutile Phase ◽

Hydroxyl Groups ◽

Bone Implant ◽

Implant System

Here, we present a bone implant system of phase-oriented titanium dioxide (TiO2) fabricated by the micro-arc oxidation method (MAO) on β-Ti to facilitate improved osseointegration. This (101) rutile-phase-dominant MAO TiO2 (R-TiO2) is biocompatible due to its high surface roughness, bone-mimetic structure, and preferential crystalline orientation. Furthermore, (101) R-TiO2 possesses active and abundant hydroxyl groups that play a significant role in enhancing hydroxyapatite formation and cell adhesion and promote cell activity leading to osseointegration. The implants had been elicited their favorable cellular behavior in vitro in the previous publications; in addition, they exhibit excellent shear strength and promote bone–implant contact, osteogenesis, and tissue formation in vivo. Hence, it can be concluded that this MAO R-TiO2 bone implant system provides a favorable active surface for efficient osseointegration and is suitable for clinical applications.

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Geometric correction for thermographic images of asteroid 162173 Ryugu by TIR (thermal infrared imager) onboard Hayabusa2

Earth Planets and Space ◽

10.1186/s40623-021-01437-w ◽

2021 ◽

Vol 73 (1) ◽

Author(s):

Takehiko Arai ◽

Tatsuaki Okada ◽

Satoshi Tanaka ◽

Tetsuya Fukuhara ◽

Hirohide Demura ◽

...

Keyword(s):

Surface Roughness ◽

High Surface ◽

Thermal Inertia ◽

Thermal Infrared ◽

Shape Model ◽

Infrared Imager ◽

Least Squares Fit ◽

Temperature Maps ◽

Pixel Scale ◽

Thermal Infrared Imager

AbstractThe thermal infrared imager (TIR) onboard the Hayabusa2 spacecraft performed thermographic observations of the asteroid 162173 Ryugu (1999 JU$$_3$$ 3 ) from June 2018 to November 2019. Our previous reports revealed that the surface of Ryugu was globally filled with porous materials and had high surface roughness. These results were derived from making the observed temperature maps of TIR using a projection method onto the shape model of Ryugu as geometric corrections. The pointing directions of TIR were calculated using an interpolation of data from the SPICE kernels (NASA/NAIF) during the periods when the optical navigation camera (ONC) and the light detection and ranging (LIDAR) observations were performed. However, the mapping accuracy of the observed TIR images was degraded when the ONC and LIDAR were not performed with TIR. Also, the orbital and attitudinal fluctuations of Hayabusa2 increased the error of the temperature maps. In this paper, to solve the temperature image mapping problems, we improved the correction method by fitting all of the observed TIR images with the surface coordinate addressed on the high-definition shape model of Ryugu (SFM 800k v20180804). This correction adjusted the pointing direction of TIR by rotating the TIR frame relative to the Hayabusa2 frame using a least squares fit. As a result, the temperature maps spatially spreading areas were converged within high-resolved $$0.5^\circ$$ 0 . 5 ∘ by $$0.5^\circ$$ 0 . 5 ∘ maps. The estimated thermal inertia, for instance, was approximately 300$$\sim$$ ∼ 350 Jm$$^{-2}$$ - 2 s$$^{-0.5}$$ - 0.5 K$$^{-1}$$ - 1 at the hot area of the Ejima Saxum. This estimation was succeeded in case that the surface topographic features were larger than the pixel scale of TIR. However, the thermal inertia estimation of smooth terrains, such as the Urashima crater, was difficult because of surface roughness effects, where roughness was probably much smaller than the pixel scale of TIR.

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Mechanical Characterization and Thermodynamic Analysis of Laser-Polished Landscape Design Products Using 3D Printing

Materials ◽

10.3390/ma14102601 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2601

Author(s):

Yue Ba ◽

Yu Wen ◽

Shibin Wu

Keyword(s):

Surface Roughness ◽

3D Printing ◽

Fused Deposition Modeling ◽

High Surface ◽

Landscape Design ◽

Laser Polishing ◽

Fused Deposition ◽

Design Structure ◽

3D Printed ◽

Stability And Accuracy

Recent innovations in 3D printing technologies and processes have influenced how landscape products are designed, built, and developed. In landscape architecture, reduced-size models are 3D-printed to replicate full-size structures. However, high surface roughness usually occurs on the surfaces of such 3D-printed components, which requires additional post-treatment. In this work, we develop a new type of landscape design structure based on the fused deposition modeling (FDM) technique and present a laser polishing method for FDM-fabricated polylactic acid (PLA) mechanical components, whereby the surface roughness of the laser-polished surfaces is reduced from over Ra 15 µm to less than 0.25 µm. The detailed results of thermodynamics and microstructure evolution are further analyzed during laser polishing. The stability and accuracy of the results are evaluated based on the standard deviation. Additionally, the superior tensile and flexural properties are examined in the laser-polished layer, in which the ultimate tensile strength (UTS) is increased by up to 46.6% and the flexural strength is increased by up to 74.5% compared with the as-fabricated components. Finally, a real polished landscape model is simulated and optimized using a series of scales.

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Effect of Optical and Morphological Control of Single-Structured LEC Device

Micromachines ◽

10.3390/mi12070843 ◽

2021 ◽

Vol 12 (7) ◽

pp. 843

Author(s):

Woo Jin Jeong ◽

Jong Ik Lee ◽

Hee Jung Kwak ◽

Jae Min Jeon ◽

Dong Yeol Shin ◽

...

Keyword(s):

Heat Treatment ◽

Surface Roughness ◽

Surface Properties ◽

High Efficiency ◽

High Surface ◽

Reduction Rate ◽

Operating Characteristics ◽

Emission Layer ◽

Light Emitting ◽

Stable Operating

We investigated the performance of single-structured light-emitting electrochemical cell (LEC) devices with Ru(bpy)3(PF6)2 polymer composite as an emission layer by controlling thickness and heat treatment. When the thickness was smaller than 120–150 nm, the device performance decreased because of the low optical properties and non-dense surface properties. On the other hand, when the thickness was over than 150 nm, the device had too high surface roughness, resulting in high-efficiency roll-off and poor device stability. With 150 nm thickness, the absorbance increased, and the surface roughness was low and dense, resulting in increased device characteristics and better stability. The heat treatment effect further improved the surface properties, thus improving the device characteristics. In particular, the external quantum efficiency (EQE) reduction rate was shallow at 100 °C, which indicates that the LEC device has stable operating characteristics. The LEC device exhibited a maximum luminance of 3532 cd/m2 and an EQE of 1.14% under 150 nm thickness and 100 °C heat treatment.

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Post-Processing and Surface Characterization of Additively Manufactured Stainless Steel 316L Lattice: Implications for BioMedical Use

Materials ◽

10.3390/ma14061376 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1376

Author(s):

Alex Quok An Teo ◽

Lina Yan ◽

Akshay Chaudhari ◽

Gavin Kane O’Neill

Keyword(s):

Surface Roughness ◽

Stainless Steel ◽

Surface Characterization ◽

High Surface ◽

Surface Characteristics ◽

Post Processing ◽

Stainless Steel 316L ◽

Processing Methods ◽

Particulate Debris

Additive manufacturing of stainless steel is becoming increasingly accessible, allowing for the customisation of structure and surface characteristics; there is little guidance for the post-processing of these metals. We carried out this study to ascertain the effects of various combinations of post-processing methods on the surface of an additively manufactured stainless steel 316L lattice. We also characterized the nature of residual surface particles found after these processes via energy-dispersive X-ray spectroscopy. Finally, we measured the surface roughness of the post-processing lattices via digital microscopy. The native lattices had a predictably high surface roughness from partially molten particles. Sandblasting effectively removed this but damaged the surface, introducing a peel-off layer, as well as leaving surface residue from the glass beads used. The addition of either abrasive polishing or electropolishing removed the peel-off layer but introduced other surface deficiencies making it more susceptible to corrosion. Finally, when electropolishing was performed after the above processes, there was a significant reduction in residual surface particles. The constitution of the particulate debris as well as the lattice surface roughness following each post-processing method varied, with potential implications for clinical use. The work provides a good base for future development of post-processing methods for additively manufactured stainless steel.

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