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Development of an Integrated Heating and Cooling Seat Concept for Future Automotive Thermal Management
No full textCancer Biomarker Profiling: Analysis of Colorectal Cancer-Related Proteins in Plasma Extracellular Vesicles
No full textMilimeter-Wave Display-Integrated FMCW Radar for Hand Gesture Recognition in Mobile Devices
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Chiral electroluminescence from thin-film devices based on momentum-space engineering
No full textChiral light sources are important for various applications including 3D displays, optical recording, optical communication, bioimaging, and biomedical diagnosis. Among others, CP light sources based on perovskite materials are attracting considerable attention to fully exploit their exceptional optoelectronic properties. Recently, there has been extensive research for achieving CP photoluminescence from perovskite materials. However, there was no demonstration of CP electroluminescence (EL) yet with a substantial degree of circular polarization (DCP), although it represents a critical step toward practical device applications.
In this talk, I present a recent experimental work from our group. We experimentally achieved chiral EL with a substantial DCP (~0.38) using momentum-space engineering. Although various three-dimensional and two-dimensional chiral nanostructures have been studied and engineered in real space, strong chiral optical responses can also be obtained in momentum space. In our design, a periodic lattice of inversion-symmetry-broken polycrystalline silicon (poly-Si) patterns is integrated with an inorganic perovskite (CsPbBr3) EL device. The bottom poly-Si layer and top metal layer forms a photonic cavity. In our device, a pair of left circularly polarized (LCP) and right circularly polarized (RCP) EL is split into two opposite directions with equal power. Because many chiral applications require both LCP and RCP light sources, our design may be desirable for various applications requiring the compact chiral light sources
Dynamic poly(hindered urea) hybrid network materials crosslinked with reactive methacrylate polymer
No full textCovalent adaptive networks (CANs) crosslinked with dynamic covalent bonds, particularly hindered urea bonds (HUBs), have gained significant attention in the development of advanced materials exhibiting self-healability and reprocessability for various applications. Multifunctional crosslinkers bearing bulky t-butylamino groups, as small molecules or macromolecules, have been incorporated into the fabrication of dynamic HUB-based CAN materials. Herein, we report a well-defined polymethacrylate homopolymer (PM) bearing t-butylamino pendants as a multifunctional bulky amine crosslinker synthesized by a controlled radical polymerization. The polyaddition of the synthesized PM with polyisocyanate and polyamine allows for the fabrication of dynamic poly(hindered urea) (PHU) networks crosslinked through the formation of reversible HUBs. Their structure-property relationship and self-healing mechanism are explored with varying amounts of PM crosslinker. The fabricated PM-PHU hybrid networks designed with excess t-butylamino pendants (e.g., more PM) exhibit rapid void-filling and network relaxation with lower activation energy, even though they possess higher mechanical strength, thus leading to excellent reprocessability with high recovery of tensile/mechanical properties upon many recycles. Our work demonstrates that the design of multifunctional polymeric crosslinkers bearing t-butylamino pendants is a promising strategy for the development of advanced HUB-based hybrid network materials with improved reprocessability. Dynamic poly(hindered urea) hybrid networks crosslinked with a well-defined polymethacrylate exhibited rapid network relaxation with lower activation energy when designed with excess t-butylamino pendants, thus leading to excellent reprocessability
Guaiacol as an Organic Superoxide Dismutase Mimics for Anti-ageing a Ru-based Li-rich Layered Oxide Cathode
No full textHigh-capacity Li-rich layered oxides using oxygen redox as well as transition metal redox suffer from its structural instability due to lattice oxygen escaped from its structure during oxygen redox and the following electrolyte decomposition by the reactive oxygen species. Herein, we rescued a Li-rich layered oxide based on 4d transition metal by employing an organic superoxide dismutase mimics as a homogeneous electrolyte additive. Guaiacol scavenged superoxide radicals via dismutation or disproportionation to convert two superoxide molecules to peroxide and dioxygen after absorbing lithium superoxide on its partially negative oxygen of methoxy and hydroxyl groups. Additionally, guaiacol was decomposed to form a thin and stable cathode-electrolyte interphase (CEI) layer, endowing the cathode with the interfacial stability
A modified approach for measuring the air permeability of ultra-high performance concrete (UHPC) under vacuum conditions
No full textThis study proposes a novel test method of the air permeability measurement under extreme vacuum condition to examine the performance of materials for Hyperloop tubes. Tests on cement-based materials demonstrated that the developed test setup was effective in measuring air permeability in extreme vacuum conditions. The results show that ultra-high performance concrete (UHPC) has significantly lower air permeability (10???18 m2) in vacuum conditions than other cement-based materials (10???16 m2) due to its dense microstructure and reduced pore size, which were within the range of previous results (10-18-10-16 m2). The measured porosity results had a strong correlation with air permeability (R2 > 0.97), validating the suitability of the proposed method for measuring the air permeability of cement-based materials in vacuum conditions. These findings provide fundamental material properties for the design of Hyperloop tube structures
Can Eye Gaze Improve Emotional State Detection on Off the Shelf Smart Devices Jiwan Kim Doyoung Lee Jaeho Kim
No full textSmartphones and wearable technology have revolutionized digital healthcare through the use of rich sensor data. Digital phenotyping, a field that uses smartphone data to detect or recognize cognitive, behavioral, or affective states and traits, is often based on data from sensors (such as inertial or touch sensors), activity or user logs, and user-generated content. In this paper, we propose the use of eye gaze as a new digital biomarker for affect detection, leveraging the advanced capabilities of off the-shelf smart devices. We designed two studies in the Instagram use scenario to detect emotional state change using gaze data. The first study took place in a controlled setting and help us understand the value of gaze features for affect detection. In this study, we achieved a peak accuracy of 76.4% for binary valence detection. The second study will be conducted over a longer period in real-world settings, with a larger population, to assess the effectiveness of our approach. By including this new sensing modality in affective digital phenotyping, we plan to improve the reliability and robustness of emotional state detection. ?? 2023 IEEE
COSMOS: Coordinated Management of Cores, Memory, and Compressed Memory Swap for QoS-Aware and Efficient Workload Consolidation for Memory-Intensive Applications
No full textWith the rapid growth in memory demands, the slowdown of DRAM scaling, and the DRAM price fluctuations, DRAM has become one of the critical resources in cloud computing systems and datacenters. The compressed memory swap (CMS) is a promising technique that improves the effective memory capacity of the underlying computer system by compressing and storing a subset of pages in memory instead of the disk swap. While prior works have extensively investigated resource management techniques for workload consolidation, they lack the capability of dynamically allocating cores, memory, and CMS to the consolidated applications in a controlled and efficient manner. To bridge this gap, this work presents the in-depth characterization of the impact of cores, memory, and CMS on the QoS and throughput
of the consolidated latency-critical (LC) and batch applications. Guided by the characterization results,
we propose COSMOS, a software-based runtime system for coordinated management of cores, memory,
and CMS for QoS-aware and efficient workload consolidation for memory-intensive applications. COSMOS
dynamically collects the runtime data from the consolidated applications and the underlying system and
allocates the resources to the consolidated applications in a way that achieves high throughput with strong
QoS guarantees. Our quantitative evaluation based on a real system and widely-used memory-intensive
benchmarks demonstrates the effectiveness of COSMOS in that it robustly satisfies the QoS and achieves
high throughput across all the evaluated workload mixes and scenarios and significantly reduces the number
of explored system states