Search

Neurodegenerative diseases, including Alzheimer's disease (AD), pose significant challenges to global healthcare because of their irreversible postsymptomatic progression. Conventional radiographic techniques have limitations in early detection, owing to the time lapse between symptom recognition by individuals and precise inspection using medical instruments. Current research explores ophthalmic approaches to address this gap, investigating the physiological link between ocular health and brain diseases. Intraocular lenses (IOLs), widely used in cataract and refractive surgeries, provide a safe and minimally invasive platform for the continuous monitoring of neurodegenerative disease biomarkers, including those associated with AD. By integrating biomolecule‐responsive sensors with IOLs, it becomes feasible to achieve early diagnosis and long‐term, noninvasive monitoring postimplantation. Herein, a fluorescently labeled inverse opal hydrogel (FIOH) is merged with IOLs for ApoE4 detection, a key risk factor for AD. The permeability and inherent photonic properties of FIOH facilitate the cumulative enhancement of the fluorescence signal. In a simulation of the aqueous humor circulation, the detection limit for ApoE4 is determined to be 0.1 nM. Therefore, FIOH‐integrated IOLs hold promise not only for early detection but also for providing a reliable platform for the continuous, noninvasive monitoring of neurodegenerative diseases after the initial, minimally invasive implantation.

Abstract Fatty acid synthesis (FAS) is essential for the production of biological components such as cell membrane building blocks and metabolism-related compounds. There are two types of bacterial FAS: de novo FAS and FAS through the incorporation of external fatty acids. Enterococcus faecalis possesses two distinct acyl carrier proteins (ACPs), AcpA (EfAcpA) and AcpB (EfAcpB), which serve as cofactors in the two types of FAS. We previously showed through NMR spectroscopy that EfAcpA comprises only three long helices, while EfAcpB consists of four helices, including a short α3 helix, similar to other bacterial ACPs. An increase in melting temperature (Tm) from 64.0 to 76.1 °C confirmed that protein structural stability increased in the presence of calcium ions. Using NMR spectroscopy, two metal binding sites were identified in EfAcpA: site A was located at the start of the α2 helix while site B was situated near the α2 helix and α2α3 loop. To understand the importance of structural flexibility of EfAcpA in de novo FAS, we investigated its motional properties using backbone spin relaxation and molecular dynamics simulations. The α2α3 loop in EfAcpA displayed high flexibility, as indicated by low heteronuclear NOE values. The residues Val51, Glu54, and Gly58 exhibited significant R 2 values, likely due to the movement of this loop. EfAcpA created a novel cavity towards the α1α2 loop, in contrast to conventional cavity formation in most bacterial ACPs. This unique behavior was attributed to the flexibility exhibited by the α2α3 loop. The structural and motional characteristics of EfAcpA confirmed that its conformational plasticity is a crucial factor influencing acyl chain transfers in de novo FAS. Given the increasing antibiotic resistance observed for E. faecalis in clinical settings, the findings of this study may contribute to the development of more effective pathogen management strategies targeting FAS.

Abstract Mass spectrometry (MS)-based intact mass analysis and structural characterization of biotherapeutic proteins such as monoclonal antibodies (mAbs) are a crucial characterization approach from upstream drug development to downstream product analysis. Due to various endogenous modifications leading to the structural heterogeneity and several N-linked glycan species resulting in macro-heterogeneity, it is challenging to characterize the mAbs. Hence, it is essential to understand the micro-heterogeneity of such proteins with high level of complexity which may vary in charge, size, or hydrophobicity. The development of high-throughput native separation techniques hyphenated with MS with high sensitivity and excellent mass accuracy has improved the top/middle down analysis, intact mass detection, subunit analysis, enhanced sequence coverage, and accurate localization of site-specific modifications. In this review, we have focused on the critical inroads taken for the improvement in MS-based techniques to resolve the challenges related to analysis of mAbs. Various MS-based techniques and their role in high-order structural analysis and the progress in software development have been explained, and further, the challenges remaining have been discussed. Graphical Abstract

The rapid evolution of microelectronics and display technologies has driven the demand for advanced manufacturing techniques capable of precise, high-speed microchip transfer. As devices shrink in size and increase in complexity, scalable and contactless methods for microscale placement are essential. Laser-induced forward transfer (LIFT) has emerged as a transformative solution, offering the precision and adaptability required for next-generation applications such as micro-light-emitting diodes (μ-LEDs). This study optimizes the LIFT process for the precise transfer of silicon microchips designed to mimic μ-LEDs. Critical parameters, including laser energy density, laser pulse width, and dynamic release layer (DRL) thickness are systematically adjusted to ensure controlled blister formation, a key factor for successful material transfer. The DRL, a polyimide-based photoreactive layer, undergoes photothermal decomposition under 355 nm laser irradiation, creating localized pressure that propels microchips onto the receiver substrate in a contactless manner. Using advanced techniques such as three-dimensional profilometry, X-ray photoelectron spectroscopy, and ultrafast imaging, this study evaluates the rupture dynamics of the DRL and the velocity of microchips during transfer. Optimization of the DRL thickness to 1 µm and a transfer velocity of 20 m s⁻1 achieves a transfer yield of up to 97%, showcasing LIFT’s potential in μ-LED manufacturing and semiconductor production.

In this study, we propose a fire classification system using image clustering based on a federated learning (FL) structure. This system enables fire detection in various industries, including manufacturing. The accurate classification of fire, smoke, and normal conditions is an important element of fire prevention and response systems in industrial sites. The server in the proposed system extracts data features using a pretrained vision transformer model and clusters the data using the bisecting K-means algorithm to obtain weights. The clients utilize these weights to cluster local data with the K-means algorithm and measure the difference in data distribution using the Kullback–Leibler divergence. Experimental results show that the proposed model achieves nearly 99% accuracy on the server, and the clustering accuracy on the clients remains high. In addition, the normalized mutual information value remains above 0.6 and the silhouette score reaches 0.9 as the rounds progress, indicating improved clustering quality. This study shows that the accuracy of fire classification is enhanced by using FL and clustering techniques and has a high potential for real-time detection.

Abstract Although Li‐metal has been revisited as the most attractive anode in building high‐energy‐density batteries owing to its superiority, such as ultimate theoretical capacity and lowest working voltage, notorious Li dendrite growth has plagued its practical uses. Since dendritic Li electroplating is mostly caused by poor Li+ transport and inferior stability of solid‐electrolyte interphase (SEI), an innovative reframing of the electrolyte is crucial to the success of Li‐metal anodes (LMAs). This review presents a new class of electrolytes, nano‐colloidal electrolytes (NCEs), providing a new avenue for next‐generation Li‐metal batteries (LMBs). Without searching for new salts/solvents or their compositional tuning, NCEs exploiting multi‐functional nanoparticles dispersed in liquid electrolytes can promote Li+ transport and reinforce the SEI of liquid electrolytes that are solely used. This review discusses various types of nanoparticles and their key roles in demonstrating excellent suppression of Li dendrite growth and enhancing the cycling stability of LMBs. Unraveling the underlying design principles of NCEs offers practical solutions for stabilizing LMAs, paving the way for developing intelligent battery systems.

South Korea has experienced rapid aging, and it is predicted that people aged 65 years or older will account for 20% of the total population by 2047. The proportion of one-person households is also increasing rapidly at the same time, and is expected to account for 37% of the total number of households by 2047. Such a demographic shift has led to more isolated households and social isolation, and consequently, to higher risks of solitary deaths. Central and local governments have implemented various measures, such as care services for the elderly living alone and regular checks on their status; however, there are limitations due to workforce and budget constraints. Therefore, it is necessary to explore innovative solutions that utilize digital technologies such as the internet of things (IoT) and artificial intelligence (AI) as new low-cost, high-efficiency alternatives. Innovations in digital technology have the potential to suggest new solutions to the issue of solitary death. Advanced technologies can play an important role in maximizing the effectiveness of solitary death prevention, management, and the prevention of social isolation. Although there is a growing body of research on the development of digital technology-based care services for the elderly, these studies have primarily focused on the applicability and early implementation stages of specific technologies. These studies have limitations in fully understanding the market trends of technologies and competition patterns within the industry. Therefore, it is essential to investigate trends in the latest technologies and R&D directions in a particular technology field through patents filed to protect new technologies. This study is intended to contribute to an in-depth understanding of the current status and development direction of digital technologies for the prevention of solitary deaths, and to provide a basis for future technology development. This study also contributes to establishing government policies and R&D strategies.

Controlling chromophore chirality in three‐dimensional space is crucial for understanding the structure–chiroptical relationship. Such control enables the prediction of ideal materials for use in chiral photonic applications. In this study, optically active multipyrene systems are synthesized on peptoids. Pyrene‐based chiral submonomers, (S)‐ and (R)‐1‐pyrenylethylamine (s1pye and r1pye), are successfully incorporated into peptoids as the respective (S)‐ and (R)‐N‐(1‐pyrenylethyl)glycine (Ns1pye and Nr1pye) units. NMR spectroscopy revealed length‐ and N‐acetylation‐dependent conformational homogeneity enhancement in solution, stabilizing cis‐amides in Ns1pye‐containing peptoids. The X‐ray crystal structure of Ns1pye tetramer displayed a polyproline type‐I (PPI)‐like helix. All of the pyrene‐related absorptions are circular dichroism (CD) active, and the CD signal related to the long‐axis‐polarized transition increased with helical stabilization. Intramolecular excimer generation yielded significant circularly polarized luminescence (CPL) in the excimer emission region. Early‐stage peptoids emitted left‐handed CPL, but upon acquiring a PPI‐like helix character, CPL handedness became inverted. The CPL dissymmetry factor (glum) was comparable or superior (10−2) to that of chiral organic dyes (10−5–10−2). This new class of helical pyrene‐containing peptoids provides a CPL‐active intramolecular excimer, modulating optical activity through peptoid secondary structure homogeneity.

Malicious reverse engineering of software has served as a valuable technique for attackers to infringe upon and steal intellectual property. We can employ obfuscation techniques to protect against such attackers as useful tools to safeguard software. Applying obfuscation techniques to source code can prevent malicious attackers from reverse engineering a program. However, the ambiguity surrounding the protective efficacy of these source code obfuscation tools and techniques presents challenges for users in evaluating and comparing the varying degrees of protection provided. This paper addresses these issues and presents a methodology to quantify the effect of source code obfuscation. Our proposed method is based on three main types of data: (1) the control flow graph, (2) the program path, and (3) the performance overhead added to the process—all of which are derived from a program analysis conducted by human experts and automated tools. For the first time, we have implemented a tool that can quantitatively evaluate the quality of obfuscation techniques. Then, to validate the effectiveness of the implemented framework, we conducted experiments using four widely recognized commercial and open-source obfuscation tools. Our experimental findings, based on quantitative values related to obfuscation techniques, demonstrate that our proposed framework effectively assesses obfuscation quality.

Korean forests are highly vulnerable to forest fires, which can severely damage property and human life. This necessitates the establishment of a rapid response system and the construction of firebreaks to prevent the spread of fires and protect key facilities. The existing firebreak construction methods can be classified into prevention- and response-stage methods. In the prevention stage, the progression and spread of fire are delayed, while in the response stage, primitive manual methods involving tools such as hooks are used, in addition to aerial deployment of water and fire retardants through helicopters. Herein, we propose the use of “fire-extinguishing drones” for firebreak construction during the initial, low-intensity stage of a fire before the deployment of firefighting personnel. We implement a continuous fire-extinguishing module capable of carrying six fire-extinguishing balls to verify its deployment accuracy and stable hovering capabilities. Through the operation of multiple drones using a ground control system and real-time kinematics to precisely generate designated automatic flight paths, we conducted experiments to assess the feasibility of firebreak construction by using fire-extinguishing drones to prevent the spread of wildfires. A firebreak construction field test was conducted to evaluate the accuracy of continuous fire extinguisher deployment, hovering performance during deployment, accuracy of the RTK-designated paths, and GCS performance. The proposed system achieved 100% performance on all indicators, except the accuracy of the RTK-designated paths.

Although Zr-based metal–organic frameworks (MOFs) exhibit robust chemical and physical stability in the presence of moisture and acidic conditions, their susceptibility to nucleophilic attacks from bases poses a critical challenge to their overall stability. Herein, we systematically investigate the stability of Zr-based UiO-66 (UiO = University of Oslo) MOFs in basic solutions. The impact of 11 standard bases, including inorganic salts and organic bases, on the stability of these MOFs is examined. The destruction of the framework is confirmed through powder X-ray diffraction (PXRD) patterns, and the monitored dissolution of ligands from the framework is assessed using nuclear magnetic resonance (NMR) spectroscopy. Our key findings reveal a direct correlation between the strength and concentration of the base and the destruction of the MOFs. The summarized data provide valuable insights that can guide the practical application of Zr-based UiO-66 MOFs under basic conditions, offering essential information for their optimal utilization in various settings.

This study conducted a survey to identify the best ergonomic operation method, in-vehicle location, and the effects of their combination on electronic gearshifts. A total of 15 different design alternatives were derived through combinations of three operation methods (lever slide, button push, and dial rotation) and five in-vehicle locations (left wheel spoke, right wheel spoke, upper center fascia, lower center fascia, and center console). A total of 40 respondents with diverse ages and driving experiences evaluated the 15 different design alternatives across nine ergonomic evaluation measures (accuracy, efficiency, rapidity, learnability, intuitiveness, safety, preference, memorability, and satisfaction). The study results indicated that: (1) the lever slide and button push were superior to dial rotation for the operation method; (2) the lower center facia and center console were superior for the in-vehicle location, and (3) implementing the lever slide method in the center console location was found to lead to the best combination of the operation method and in-vehicle location, while implementing the button push method in the right wheel spoke or upper center fascia location also showed relative superiority. The study findings are expected to contribute to the ergonomic design of electronic gearshifts that can enhance the driver’s gear-shifting experience, thereby improving driving performance and safety.

This Communication presents a computational design approach for a broadband in-line coaxial-to-rectangular waveguide transition having a 2.83:1 bandwidth. Existing designs have a bandwidth ranging from 1.36:1 to 2:1. The proposed transition consists of a four-step ridge transformer and three sections of the rectangular waveguide. The proposed design approach extends the bandwidth of the transition by a theory-based design of the width and height of the three-section waveguides and by a computer-aided optimization of the stepped-ridge transformer. The dimensions of the three waveguide sections are determined such that the transition operates from very close to the TE10-mode cutoff to slightly less than the TE30-mode cutoff. A four-step ridge transformer was computer-optimized for a low reflection coefficient over a broad bandwidth. The proposed design approach was applied to the design of a coaxial-to-WR75 transition whose reflection coefficient is less than −22.6 dB at 8.14–23.00 GHz (2.83:1 bandwidth). The dimensions of the proposed transition were obtained using an electromagnetic simulation tool. The increased bandwidth of the transition can be very useful, especially in measurement applications.

The use of plate-like materials to induce a percolation gel-like effect in electrorheological (ER) fluids is sparsely documented. Hence, we dispersed plate-like materials, namely natural mica, synthetic mica, and glass, as well as their pulverized particles, in various concentrations in silicone oil to form ER fluids. Subsequently, the rheological properties of the fluids were evaluated and compared to identify the threshold concentration for percolating a gel-like state. The shear stress and viscoelastic moduli under zero-field conditions confirmed that plate-like materials can be used to induce percolation gel-like effects in ER fluids. This is because of the high aspect ratio of the materials, which enhances their physical stability. In practical ER investigations, ER fluids based on synthetic mica (30.0 wt%) showed the highest yield stress of 516.2 Pa under an electric field strength of 3.0 kV mm−1. This was attributed to the formation of large-cluster networks and additional polarization induced by the ions. This study provides a practical approach for developing a new type of gel-like ER fluid.

For miniaturization, rectangular waveguides with a reduced height are often required, along with a coaxial transition for signal launching. We present a simulation-based design of a broadband transition from a coaxial cable to a rectangular waveguide with the height(b)-to-width(a) ratio b/a ranging from 0.125 to 0.375. The proposed transition consists of a coaxial probe with a cylindrical head or a disk and two symmetrically placed tuning posts. To extend the operating frequency range, three sections of the rectangular waveguide are employed with properly chosen dimensions. Design examples are presented for the WR75 waveguide transition with a b/a of 0.125, 0.25, and 0.375, having a bandwidth of 83.4%, 92.7%, and 84.4%, respectively. Compared with previous works, our design offers the largest bandwidth in a right-angle coaxial-to-rectangular waveguide transition employing the aforementioned structure.

Herein, unique three-dimensional (3D) hierarchically structured carbon nanofiber (CNF)/metal oxide/conducting polymer composite materials were successfully synthesized by combinations of various experimental methods. Firstly, base CNFs were synthesized by carbonization of electrospun PAN/PVP fibers to attain electric double-layer capacitor (EDLC) characteristics. To further enhance the capacitance, tin oxide (SnO2) and iron oxide (Fe2O3) were coated onto the CNFs via facile hydrothermal treatment. Finally, polypyrrole (PPy) was introduced as the outermost layer by a dispersion polymerization method under static condition to obtain 3D-structured CNF/SnO2/PPy and CNF/Fe2O3/PPy materials. With each synthesis step, the morphology and dimension of materials were transformed, which also added the benign characteristic for supercapacitor application. For the practical application, as-synthesized CNF/SnO2/PPy and CNF/Fe2O3/PPy were applied as active materials for supercapacitor electrodes, and superb specific capacitances of 508.1 and 426.8 F g−1 (at 1 A g−1) were obtained (three-electrode system). Furthermore, an asymmetric supercapacitor (ASC) device was assembled using CNF/SnO2/PPy as the positive electrode and CNF/Fe2O3/PPy as the negative electrode. The resulting CNF/SnO2/PPy//CNF/Fe2O3/PPy device exhibited excellent specific capacitance of 101.2 F g−1 (at 1 A g−1). Notably, the ASC device displayed a long-term cyclability (at 2000 cycles) with a retention rate of 81.1%, compared to a CNF/SnO2//CNF/Fe2O3 device of 70.3% without an outermost PPy layer. By introducing the outermost PPy layer, metal oxide detachment from CNFs were prevented to facilitate long-term cyclability of electrodes. Accordingly, this study provides an effective method for manufacturing a high-performance and stable supercapacitor by utilizing unique 3D hierarchical materials, comprised of CNF, metal oxide, and conducting polymer.

Human–computer interaction (HCI) is a multidisciplinary field that investigates the interactions between humans and computer systems. HCI has facilitated the development of various digital technologies that aim to deliver optimal user experiences. Gaze recognition is a critical aspect of HCI, as it can provide valuable insights into basic human behavior. The gaze-matching method is a reliable approach that can identify the area at which a user is looking. Early methods of gaze tracking required users to wear glasses with a tracking function and limited tracking to a small monitoring area. Additionally, gaze estimation was restricted to a fixed posture within a narrow range. In this study, we proposed a novel non-contact gaze-mapping system that could overcome the physical limitations of previous methods and be applied in real-world environments. Our experimental results demonstrated an average gaze-mapping accuracy of 92.9% across 9 different test environments. Moreover, we introduced the GIST gaze-mapping (GGM) dataset, which served as a valuable resource for learning and evaluating gaze-mapping techniques.

The remarkable development of the Internet has made our lives very convenient, such as through the ability to instantaneously transmit individual pictures. As a result, cyber-attacks are also being developed and increasing, and the computer/mobile devices we use can become infected with viruses in an instant. Rapid cyber situational awareness is essential to prepare for such cyber-attacks. Accelerating cyber situational awareness requires Cyber Common Operational Pictures, which integrate and contextualize numerous data streams and data points. Therefore, we propose a Cyber Common Operational Pictures framework and criteria for rapid cyber situation awareness. First, the system reaction speed based on the user’s request and the standard for easily recognizing the object shown on the screen are presented. Second, standards and frameworks for five types of visualization screens that can directly recognize and respond to cyber-attacks are presented. Third, we show how a system was constructed based on the proposed framework, as well as the results of an experiment on the response time of each visualization screen. As a result of the experiment, the response speed of the 5 visualization screens was about 0.11 s on average for inquiry (simple) and 1.07 s on average for inquiry (complex). This is consistent with the typical response times of the studies investigated in this paper. If CyCOP is developed in compliance with the framework items (UI, object symbol, object size, response speed) presented in this paper, rapid situational awareness is possible. This research can be used in cyber-attack and defense training in the military field. In the private sector, it can be used in cyber and network control.

In this study, a flexible all-solid-state asymmetric supercapacitor (FASC) device has been successfully fabricated via full recycling of heated tobacco waste (HTW). Tobacco leaves and cellulose acetate tubes have been successfully carbonized (HTW-C) and mixed with metal oxides (MnO2 and Fe3O4) to obtain highly active materials for supercapacitors. Moreover, poly(lactic acid) (PLA) filters have been successfully dissolved in an organic solvent and mixed with the as-prepared active materials using a simple paste mixing method. In addition, flexible MnO2- and Fe3O4-mixed HTW-C/PLA electrodes (C-MnO2/PLA and C-Fe3O4/PLA) have been successfully fabricated using the drop-casting method. The as-synthesized flexible C-MnO2/PLA and C-Fe3O4/PLA electrodes have exhibited excellent electrical conductivity of 378 and 660 μS cm−1, and high specific capacitance of 34.8 and 47.9 mF cm−2 at 1 mA cm−2, respectively. A practical FASC device (C-MnO2/PLA//C-Fe3O4/PLA) has been assembled by employing the C-MnO2/PLA as the positive electrode and C-Fe3O4/PLA as the negative electrode. The as-prepared FASC device showed a remarkable capacitance of 5.80 mF cm−2 at 1 mA cm−2. Additionally, the FASC device manifests stable electrochemical performance under harsh bending conditions, verifying the superb flexibility and sustainability of the device. To the best of our knowledge, this is the first study to report complete recycling of heated tobacco waste to prepare the practical FASC devices. With excellent electrochemical performance, the experiments described in this study successfully demonstrate the possibility of recycling new types of biomass in the future.

Over the past few decades, advances in various nanophotonic structures to enhance light–matter interactions have opened numerous opportunities for biosensing applications. Beyond the successful development of label-free nanophotonic biosensors that utilize plasmon resonances in metals and Mie resonances in dielectrics, simpler structures are required to achieve improved sensor performance and multifunctionality, while enabling cost-effective fabrication. Here, we present a simple and effectual approach to colorimetric biosensing utilizing a trilayered Gires–Tournois (GT) resonator, which provides a sensitive slow-light effect in response to low refractive index (RI) substances and thus enables to distinguish low RI bioparticles from the background with spatially distinct color differences. For low RI sensitivity, by impedance matching based on the transmission line model, trilayer configuration enables the derivation of optimal designs to achieve the unity absorption condition in a low RI medium, which is difficult to obtain with the conventional GT configuration. Compared to conventional bilayered GT resonators, the trilayered GT resonator shows significant sensing performance with linear sensitivity in various situations with low RI substances. For extended applications, several proposed designs of trilayered GT resonators are presented in various material combinations by impedance matching using equivalent transmission line models. Further, comparing the color change of different substrates with low RI NPs using finite-difference time-domain (FDTD) simulations, the proposed GT structure shows surpassing colorimetric detection.

A systematic electrochemical study was conducted to investigate the reduction of tellurium (Te) in alkaline solutions. The effect of various parameters, including tellurite ion concentration, applied potential, and pH was investigated by both linear sweep voltammograms (LSVs) and electrochemical quartz crystal microbalance (EQCM). EQCM was essential to understand the reduction of Te(0) to soluble Te22-(-I) or Te2−(-II). The Tafel slopes for two Te reduction reactions [i.e., Te(IV) to Te(0) and Te(0) to Te(-I)] indicated that the electrochemical reduction of Te is strongly dependent on solution pH, whereas it is independent of the concentration of TeO32-. At relatively weaker alkaline solutions (i.e., pH ≤ 12.5), the discharge of Te(OH)3+ was determined to be the rate-limiting step during the reduction of Te(IV) to Te(0). For the reduction of Te(0) to Te(-I), the reaction follows a four-step reaction, which consisted of two discharge and two electrochemical reactions. The second discharge reaction was the rate-limiting step when pH ≤12.5 with the Tafel slope of 120 mV/decade. At a higher pH of 14.7, the Tafel slope was shifted to be 40 mV/decade, which indicated that the rate-limiting step was altered to the second electrochemical reaction. Te(0) deposits were found either on the surface of an electrode or in the solution depending on pH due to the different rate-limiting reactions, revealing that pH was a key parameter to dictate the morphology of the Te(0) deposits in alkaline media.

Organic entities that can transport electrons are seldom available to develop adequate bipolar host materials applicable for solution-processable thermally activated delayed fluorescence (TADF)-organic light-emitting diodes (OLEDs). Therefore, the introduction of new electron-affine entities that plausibly demonstrate high triplet energy (ET) is of urgent need. In this contribution, we introduced benzimidazo[1,2-a][3,1]benzothiazine (BBIT) as a novel electron-affine entity and developed two new bipolar host materials, CzBBIT and 2CzBBIT. Both host materials exhibit high ET of 3.0 eV, superior thermal robustness with the thermal decomposition temperature of up to 392°C, a glass transition temperature of up to 161°C, and high solubility in common organic solvents. Consequently, the solution-processable OLEDs fabricated using a recognized IAcTr-out as the green TADF emitter doped into CzBBIT as the host, realized a maximum external quantum efficiency (EQE) of 23.3%, while the 2CzBBIT:IAcTr-out blend film-based device displayed an EQE of 18.7%. These outcomes corroborated that this work could shed light on the scientific community on the design of new electron-affine entities to establish the effective use of bipolar host materials toward proficient solution-processable TADF-OLEDs.

Ultra-thin and large-area silicon wafers with a thickness in the range of 20–70 μm, were produced by spalling using a nickel stressor layer. A new equation for predicting the thickness of the spalled silicon was derived from the Suo–Hutchinson mechanical model and the kinking mechanism. To confirm the reliability of the new equation, the proportional factor of stress induced by the nickel on the silicon wafer, was calculated. The calculated proportional factor of λ = 0.99 indicates that the thickness of the spalled silicon wafer is proportional to that of the nickel layer. A similar relationship was observed in the experimental data obtained in this study. In addition, the thickness of the stressor layer was converted to a value of stress as a guide when using other deposition conditions and materials. A silicon wafer with a predicted thickness of 50 μm was exfoliated for further analysis. In order to spall a large-area (150 × 150 mm2 or 6 × 6 in2) silicon wafer without kerf loss, initial cracks were formed by a laser pretreatment at a proper depth (50 μm) inside the exfoliated silicon wafer, which reduced the area of edge slope (kerf loss) from 33 to 3 mm2. The variations in thickness of the spalled wafer remained under 4%. Moreover, we checked the probability of degradation of the spalled wafers by using them to fabricate solar cells; the efficiency and ideality factor of the spalled silicon wafers were found to be 14.23%and 1.35, respectively.

This study investigated the principal translational or rotational axis that evokes the most severe cybersickness by detecting constant velocity and acceleration thresholds on the onset of cybersickness. This human subject experiment with 16 participants used a 3D particle field with movement directions (lateral, vertical, yaw, or pitch) and motion profiles (constant velocity or constant acceleration). The results showed that the threshold of pitch optical flow was suggestively lower than that of the yaw, and the vertical threshold was significantly lower than the lateral. Still, there was no effect of scene movement on the level of cybersickness. In four trials, the threshold increased from the first to the second trial, but the rest remained the same as the second one. However, the level of cybersickness increased significantly between the trials on the same day. The disorientation-related symptoms occurred on the first trial day diminished before the second trial day, but the oculomotor-related symptoms accumulated over the days. Although there were no correlations between the threshold and total cybersickness severity, participants with a lower threshold experienced severe nausea. The experimental findings can be applied in designing motion profiles to reduce cybersickness by controlling the optical flow in virtual reality.