- 标题
- 摘要
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- 实验方案
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Multisegmented Metallic Nanorods: Sub-10 nm Growth, Nanoscale Manipulation, and Subwavelength Imaging
摘要： Multisegmented metallic nanorods (MS-M-NRs) have attracted increasing attention thanks to their integrated structures and complex functions. The integration of nanoscale segments in 1D enables maximum exposure of each segment and enhanced interaction between adjacent segments. Such structural integration will induce functional complexity in the nanorods, leading to superior properties for the individual components. Herein, recent progress on the development of MS-M-NRs is reviewed. Their precise fabrication, nanoscale manipulation, and subwavelength imaging, as well as simultaneous manipulation and imaging are discussed, respectively. Specifically, precise fabrication of MS-M-NRs focuses on porous anodic alumina (PAA) templated electrodeposition, which enables sub-10 nm growth of the segments and their interfaces/fronts. Nanoscale manipulation of MS-M-NRs introduces the fundamental methods that are employed for delicate movement control on the nanorods through internal or external stimulations. Subwavelength imaging of MS-M-NRs highlights the achievements on identification and location of constituent nanoscale segments/gaps based on their differences and interactions. Simultaneous manipulation and imaging of MS-M-NRs addresses the significance and potential applications of the nanorods with magnetic–plasmonic dual modulation. The development of MS-M-NRs will greatly contribute to materials science and nanoscience/nanotechnology.
关键词： metallic nanorods,porous anodic alumina (PAA),electrodeposition,imaging,manipulation
更新于2025-09-23 15:22:29
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Photoluminescent Properties and Local Structure of Tb Doped Fibrous Alumina
摘要： A boehmite sol which contains uniform ?brous nanoparticles has a unique property to form a ?lm by its self-assembling properties. When Tb ions were added to the sol, the ?lm became photoluminescent (PL) and emitted bright green light due to the f-f transition of Tb by UV irradiation. The PL intensity varied with calcination temperature during pretreatment. The best performance was obtained when the sample was treated around 800 °C. The PL performance normalized by the Tb content was higher for samples with a lower Tb content. Structural analysis by TEM, XRD, and XAFS revealed that when the Tb content was lower than Tb/Al = 2.5/97.5 in the atomic ratio, Tb ions were dispersed on the alumina surface isolated from each other, and those Tb species showed a high PL performance. On the other hand, for densely Tb doped samples, excessive Tb ions aggregated and formed Tb oxide nanoparticles, which were supposed to have lower PL e?ciencies.
关键词： Fibrous alumina,Photoluminescence,Terbium
更新于2025-09-23 15:21:21
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Channel-Length Dependent Performance Degradation of Thermally Stressed IGZO TFTs
摘要： The focus of this work is on the performance degradation of thermally stressed IGZO TFTs with SiO2 for both the gate dielectric and back-channel passivation material. I-V characteristics of TFTs with bottom-gate (BG) and double-gate (DG) electrode configurations were observed to left-shift and degrade with thermal stress. Experimental results indicate the instability occurs either directly or indirectly due to the influence of H2O within the passivation oxide above the IGZO channel region. An atomic layer deposition (ALD) alumina capping layer applied immediately following the passivation oxide anneal was successful in improving thermal stability. Channel length dependence was observed where longer channel DG devices were more prone to degradation. A hypothesis has been developed with H2O as the expected origin of this phenomenon. Experiments have been specifically designed to establish the feasibility of the proposed mechanism. Furthermore, DG devices which exhibit enhanced thermal stability are presented.
关键词： thermal stability,SiO2 passivation,ALD alumina capping,IGZO TFTs,channel length dependence
更新于2025-09-23 15:21:01
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[Ceramic Engineering and Science Proceedings] Advanced Processing and Manufacturing Technologies for Nanostructured and Multifunctional Materials (A Collection of Papers Presented at the 38th International Conference on Advanced Ceramics and Composites January 27-31, 2014 Daytona Beach, Florida) || Advanced Measurements of Indentation Fracture Resistance of Alumina by the Powerful Optical Microscopy for Small Ceramic Products
摘要： A round robin on indentation fracture resistance, KIFR of two types of alumina with different purity was conducted by thirteen laboratories in order to confirm the reliability of the IF method using powerful optical microscopy. Our new approach employed both an objective lens of 40x or 50x and a traveling stage to reduce the measuring error of crack lengths. The standard deviations of KIFR reported for the two samples indented at 98 N were 0.3 and 0.2 MPa m1/2 for mean KIFR of 4.3 and 3.6 MPa m1/2, respectively, indicating good matching between different laboratories. The grand averages of KIFR for both samples from all participants were only 0.4 MPa m1/2 higher than those of KIFR re-measured by the authors using the returned samples, which demonstrated a little room for improvement of the new technique. The results in this study together with the previous two round robins for SiC and Si3N4 ceramics revealed that the reliability of the IF method has reached a sufficient level since the reproducibility of KIFR for the three major ceramics was verified reasonable.
关键词： KIFR,alumina,indentation fracture resistance,optical microscopy,round robin
更新于2025-09-23 15:21:01
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Preliminary Characterization of Glass/Alumina Composite Using Laser Powder Bed Fusion (L-PBF) Additive Manufacturing
摘要： Powder bed fusion (PBF) additive manufacturing (AM) is currently used to produce high-efficiency, high-density, and high-performance products for a variety of applications. However, existing AM methods are applicable only to metal materials and not to high-melting-point ceramics. Here, we develop a composite material for PBF AM by adding Al2O3 to a glass material using laser melting. Al2O3 and a black pigment are added to a synthesized glass frit for improving the composite strength and increased laser-light absorption, respectively. Our sample analysis shows that the glass melts to form a composite when the mixture is laser-irradiated. To improve the sintering density, we heat-treat the sample at 750°C to synthesize a high-density glass frit composite. As per our X-ray diffraction (XRD) analysis to confirm the reactivity of the glass frit and Al2O3, we find that no reactions occur between glass and crystalline Al2O3. Moreover, we obtain a high sample density of ≥95% of the theoretical density. We also evaluate the composite’s mechanical properties as a function of the Al2O3 content. Our approach facilitates the manufacturing of ceramic 3D structures using glass materials through PBF AM and affords the benefits of reduced process cost, improved performance, newer functionalities, and increased value addition.
关键词： density,powder bed fusion,additive manufacturing,mechanical property,3D printing,glass/alumina composite
更新于2025-09-23 15:21:01
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Deep and high precision cutting of alumina ceramics by picosecond laser
摘要： Ceramics possess high thermal and chemical resistance, low density, and high compressive strength; however, the machining complications imposed by their inherent brittleness limit their range of applications. Laser cutting technology can offer an automated manufacturing technique for machining these brittle materials. In this paper, a laser cutting method, so-called wobbling, was developed for performing deep, high precision, and defect-free laser cutting of industrial grade alumina ceramics. This work explored picosecond laser process parameters such as focal position, linear speed, and wobble amplitude in order to control cut depth and optimize cut quality in terms of kerf width, kerf taper, surface cleanness, while avoiding crack formation. The morphology and cut quality were evaluated using 3D laser scanning microscopy and scanning electron microscopy (SEM). Picosecond laser cutting process parameters were optimized, achieving a maximum material removal rate of ~10 mm3/min. It was shown that the laser cutting process developed via these experiments represents an effective and efficient manufacturing tool that can be incorporated in engineered net shaping systems.
关键词： Laser cutting,Material removal rate,Ablation,Ultrafast laser micromachining,Alumina ceramics
更新于2025-09-23 15:21:01
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The restoration of the friction surfaces by laser cladding
摘要： The paper deals with laser cladding of wear-resistant coatings for restoring friction surfaces. It describes the modes of cladding technological process, and presents the results of wear tests. Wear-resistant coating based on the Ni-Cr-B-Si and alumina system, which exceeds 30HGSA steel by 11.5 times by wear resistance.
关键词： wear-resistant coatings,alumina,friction surfaces,Ni-Cr-B-Si,laser cladding
更新于2025-09-23 15:19:57
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Ultrasensitive and Label-Free Detection of Cell Surface Glycan Using Nanochannel-Ionchannel Hybrid Coupled with Electrochemical Detector
摘要： In this work, asymmetric nanochannel-ionchannel of porous anodic alumina (PAA) coupled with electrochemical detector was used for sensitive and label-free detection of cell surface glycan. The amplified ionic current caused by array nanochannels as well as the ionic current rectification (ICR) caused by asymmetric geometry endows PAA with sensitive ionic current response. Functionalized with the special molecular probe, the constructed nanofluidic device can be used for selective recognition and detection of glycan in real-time and label-free format. In addition, due to the subnanosize of ionchannels, the probe immobilization and glycan recognition is carried out on the outer surface of PAA, avoiding the blockage of PAA nanochannel by samples, which promises the reproducibility and accuracy of the present method toward bioanalysis. Results show that the glycan concentration ranging from 10 fM to 10 nM can be successfully detected with a detection limit of ~10 aM, which is substantially lower than most previous works. The designed strategy provides a valuable platform for sensitive and label-free detection of cell surface glycan, which acts as a promising candidate in pathological research and cancer diagnosis.
关键词： porous anodic alumina,ionic current rectification,cell surface glycan,nanochannel-ionchannel hybrid,nanofluidics
更新于2025-09-23 15:19:57
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Experimental study with analysis for a novel saturated activated alumina photovoltaic thermal system
摘要： This paper presents a novel photovoltaic thermal system based on water absorption-desorption phenomenon using activated alumina. Experimental work for a promising photovoltaic thermal system that utilise activated alumina tablets as heat absorbing and storing element is presented. Based on the experimental results, electrical, thermal and combined energy efficiencies were calculated and compared with the stand-alone PV panel efficiency. Three identical systems -containing 10 cm depth saturated activated alumina mixed with aluminium mesh cuts-were attached to the back surface of simulated solar panel. The three systems were tested at 600, 800 and 1000 W/m2 for 6 consecutive working hours, representing sun shining time. Results showed a net energy efficiency of 57% and 53.6% at 600 W/m2 and 1000 W/m2 respectively. The electrical efficiency increased by 10.4% and 6.7% at 600 W/m2 and 1000 W/m2, respectively, compared with the stand-alone panel. This led to an increase in total energy generation by 309% and 319.5% at 600 W/m2 and 1000 W/m2 respectively, compared with stand-alone solar panel.
关键词： Solar panels,PV/T,Activated alumina,Materials,Saturated,Cooling
更新于2025-09-23 15:19:57
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Aligning ?±a??alumina platelets via uniaxial pressing of ceramica??filled polymer blends for improved sintered transparency
摘要： Uniaxial warm pressing was used to align alumina platelet-filled polyethylene-based copolymer blends. The solids loading (30-40 vol.%) and platelet diameter (1.2 and 11 μm) were varied to compare effects on viscosity, percent reduction, and final alignment. All ceramic-filled thermoplastic polymer blends exhibited pseudoplastic behavior. Crystallographic alignment of green body samples was quantified by the orientation parameter (r) and grain misalignment angle (full width at half maximum, FWHM) obtained from rocking curve analysis. Blends with 11 μm diameter platelets displayed a higher temperature sensitivity constant, better flow properties, and higher alignment compared to blends with 1.2 μm diameter platelets. Optimal samples produced with blends containing 30 vol.% of 11 μm diameter platelets demonstrated an alignment of r = .251 ± .017; FWHM = 11.16° ± 1.16°. A sample with optimal alignment was hot-pressed to transparency and obtained an in-line transmission of 70.0% at 645 nm. The final alignment of this pre-aligned hot-pressed sample (r = .254 ± .008; FWHM = 11.38° ± 0.54°) improved when compared to a non-pre-aligned sample (r = .283 ± .005; FWHM = 13.40° ± 0.38°).
关键词： hot pressing,rheology/rheometry,alumina,optical materials/properties
更新于2025-09-19 17:13:59