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991.
992.
Brandon Fields Mahsa Amiri Jungyun Lim Julia T. Pürstl Matthew R. Begley Diran Apelian Lorenzo Valdevit 《Advanced Materials Technologies》2024,9(5):2301037
The established approach to materials design for additive manufacturing (AM) consists of attempting to reproduce the uniform structures and properties of conventionally processed materials. While this certainly helped facilitate material certification and the rapid introduction of AM technologies in several industries, the opportunity to exploit unique features of specific AM processes to generate spatially varying microstructures–and hence novel materials, remains largely untapped. This work presents a method for manufacturing materials through laser powder bed fusion (LPBF), in which control over the spatial variation in phase composition and mechanical properties is achieved. This technique is demonstrated using 17-4 precipitation-hardened stainless steel (17-4PH), by controlling spatial modulation of energy densities during printing. This results in local control of ferrite/martensite volume fractions, allowing the fabrication of metal/metal architected composites with hard/brittle regions interspersed with soft/tough regions. Local variations of ~20% in tensile strength and ~150% in elongation are achieved, with a spatial resolution of ~100 microns. The approach is general and robust, fully compatible with commercially available LPBF equipment, and applicable to virtually any multi-phase alloy system. This work shifts the paradigm from attempting to print components with uniform properties to manufacturing alloys with controlled spatial property gradients. 相似文献
993.
Seok Hyun Song Hwa Soo Kim Kyoung Sun Kim Seokjae Hong Hyungkwon Jeon Jun Lim Young Hwa Jung Hyungju Ahn Jong Dae Jang Man-Ho Kim Jong Hyeok Seo Ji-Hwan Kwon Dokyung Kim Young Joo Lee Young-Soo Han Kyu-Young Park Chunjoong Kim Seung-Ho Yu Hyeokjun Park Hyeong Min Jin Hyungsub Kim 《Advanced functional materials》2024,34(3):2306654
Ni-rich layered oxides are envisioned as the most promising cathode materials for next-generation lithium-ion batteries; however, their practical adoption is plagued by fast capacity decay originating from chemo-mechanical degradation. The intrinsic chemical–mechanical instability, inherited from atomic- and nanoscale defects generated during synthesis, is not yet resolved. Here, atomic- and nanoscale structural evolution during solid-state synthesis of Ni-rich layered cathode, Li[Ni0.92Co0.03Mn0.05]O2, is investigated using combined X-ray/neutron scattering and electron/X-ray microscopy. The multiscale analyses demonstrate the intertwined correlation between phase transition and microstructural evolution, with atomic-scale defects derived from the decomposition of precursors leading to the creation of intra/inter-granular pores. The nucleation and coalescence mechanism of pore defects during the synthesis of Ni-rich layered cathodes are quantitatively revealed. Furthermore, a modified synthetic route is proposed to effectively circumvent the formation of nanoscale defects in Ni-rich layered cathodes by facilitating uniform synthetic reactions, resulting in superior electrochemical and microstructural stability. 相似文献
994.
Gyu Il Jung;Hyung Jun Lim;Sang Min Lee;Sang Man Koo; 《Journal of the American Ceramic Society》2024,107(5):3508-3521
Hollow silicon carbide (SiC) particles have attracted attention due to their well-defined morphology, low density, and large surface area that can be leveraged for a wide variety of applications. Here, we report the self-templated synthesis of monodisperse hollow spherical SiC composite particles with controllable shell thicknesses using magnesiothermic reduction of organically modified silica (ORMOSIL) particles. Monodisperse ORMOSIL particles containing three organic groups of methyl, vinyl, and mercaptopropyl were produced by a simple one-pot sol–gel process and then converted to hollow spherical SiC composite particles via a magnesiothermic reduction at 700°C under an inert atmosphere. The spherical morphologies of the original ORMOSIL particles were well maintained through this self-templated conversion process, but the sizes of the hollow SiC particles were slightly reduced by the thermal treatment. Field emission transmission electron microscopy studies revealed that the shell of hollow particles mainly consists of primary β-SiC particles with nanometer-scale sizes. The physical and chemical properties of the hollow SiC composite particles were investigated by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller, X-ray diffraction, Fourier transform infrared spectroscopy, Raman, and solid-state nuclear magnetic resonance analyses. The shell thickness of hollow spherical SiC composite particles can be controlled by simply changing the duration of the thermal conversion process. This study not only provides a simple and easy approach for the preparation of hollow spherical SiC particles but also opens the possibility of large-scale manufacturing of such particles for commercial applications. 相似文献
995.
Jeong Ji Hyun Lee Ha Lim Park Hyun Ji Yoon Ye Eun Shin Jaeeun Jeong Mi-Young Park Sung Hoon Kim Da-hye Han Seung-Woo Kang Choon-Gil Hong Ki-Ju Lee Sung-Joon 《Food science and biotechnology》2023,32(8):1111-1122
Food Science and Biotechnology - Tomatoes include high levels of lycopene, which is a potent antioxidative, hypolipidemic, and antidiabetic phytochemical. The intake of lycopene is associated with... 相似文献
996.
Noh Chang-Hyun Chun Su-Hyun Lim JoonKi Kim Min-hyuk Choi Seogyeong Joo Yong-Sung Lee Kwang-Won 《Food science and biotechnology》2023,32(10):1361-1372
Food Science and Biotechnology - Rice is an important grain as a major source of carbohydrates in Asia but contains more arsenic (As) than other grains. A total of 239 rice-based processed foods... 相似文献
997.
998.
Changmin Lee Youngjae Hong Dongho Kim Younghwan Lim Jang Wook Choi Sung-Yoon Chung 《Advanced functional materials》2023,33(44):2303763
Protons in aqueous electrolytes can perform as an additional type of charge carrier for insertion/extraction in addition to the primary carrier cations in aqueous rechargeable batteries. Despite many diverse claims regarding the effect of protons, mutually conflicting experimental results and their interpretations without direct evidence have been reported over the last decade. Systematic examinations and analyses are thus imperative to clarify the conditions of proton insertion in aqueous rechargeable batteries. Utilizing V2O5 as a model cathode and beaker-type cells with a sufficient amount of ZnSO4 aqueous electrolytes in this work, it is demonstrated that protons are inserted into the cathode prior to Zn-ions in low-pH conditions (pH ≤ 3.0). In stark contrast, the influence of protons on the discharge voltage and capacity is insignificant, when either the pH becomes higher (pH ≥ 4.0) or the electrolyte volume is considerably low in coin-type cells. Similar behavior of pH-dependent proton insertion is also verified in Na–, Mg–, and Al-ion electrolytes. Providing a resolution to the controversy regarding proton insertion, the present study emphasizes that the influence of protons substantially varies depending on the pH and relative volume of electrolytes in aqueous batteries. 相似文献
999.
Dong Yun Jung Kun Sik Park Sang In Kim Sungkyu Kwon Doo Hyung Cho Hyun Gyu Jang Jongil Won Jong-Won Lim 《ETRI Journal》2023,45(3):543-550
Electrostatic discharge (ESD) testing for human body model tests is an essential part of the reliability evaluation of electronic/electrical devices and components. However, global environmental concerns have called for the need to replace the mercury-wetted relay switches, which have been used in ESD testers. Therefore, herein, we propose an ESD tester using metal oxide semiconductor-controlled thyristor (MCT) devices with a significantly higher rising rate of anode current (di/dt) characteristics. These MCTs, which have a breakdown voltage beyond 3000 V, were developed through an in-house foundry. As a replacement for the existing mercury relays, the proposed ESD tester with the developed MCT satisfies all the requirements stipulated in the JS-001 standard for conditions at or below 2000 V. Moreover, unlike traditional relays, the proposed ESD tester does not generate resonance; therefore, no additional circuitry is required for resonant removal. To the best of our knowledge, the proposed ESD tester is the first study to meet the JS-001 specification by applying a new switch instead of an existing mercury-wetted relay. 相似文献
1000.
Min Seong Kim Yung Lee Junseong Ahn Seonggi Kim Kyungnam Kang Hyuneui Lim Byeong-Soo Bae Inkyu Park 《Advanced functional materials》2023,33(3):2208792
Conventional elastomeric polymers used as substrates for wearable platforms have large positive Poisson's ratios (≈0.5) that cause a deformation mismatch with human skin that is multidirectionally elongated under bending of joints. This causes practical problems in elastomer-based wearable devices, such as delamination and detachment, leading to poorly reliable functionality. To overcome this issue, auxetic-structured mechanical reinforcement with glass fibers is applied to the elastomeric film, resulting in a negative Poisson's ratio (NPR), which is a skin-like stretchable substrate (SLSS). Several parameters for determining the materials and geometrical dimensions of the auxetic-structured reinforcing fillers are considered to maximize the NPR. Based on numerical simulation and digital image correlation analysis, the deformation tendencies and strain distribution of the SLSS are investigated and compared with those of the pristine elastomeric substrate. Owing to the strain-localization characteristics, an independent strain-pressure sensing system is fabricated using SLSS with a Ag-based elastomeric ink and a carbon nanotube-based force-sensitive resistor. Finally, it is demonstrated that the SLSS-based sensor platform can be applied as a wearable device to monitor the physical burden on the wrist in real time. 相似文献