Based on the behavioral theory of the firm, we research how performance feedback influences the formation of CEOs' passion. We articulate that previous performance directly increases CEOs' passion. ...Specifically, positive affective outcomes (performance above aspiration-level) advance CEOs' positive feelings and motivation toward the domains of success (obsessive passion). For instance, when a firm accomplishes performance objectives, such as reaching sales goals, CEOs' positive feelings toward developing current products would be boosted. Moreover, negative affective outcomes (performance below aspiration-level) would also positively impact CEOs' passion since the CEOs would endeavor to reduce the difference between performance and their aspiration-level. As such, performance feedback is a critical antecedent of CEOs' obsessive passion. In addition, we apply human capital as a moderator between performance feedback and CEOs' obsessive passion. Results based on multiphase survey data from 189 CEOs of Korean small- and medium-sized enterprises indicate that both positive and negative performance feedback positively increase CEOs' obsessive passion. Moreover, human capital negatively moderates the relationship between positive performance feedback and CEOs' obsessive passion and positively moderates the relationship between negative performance feedback and CEOs' obsessive passion.
Stretchable conductive fibers have received significant attention due to their possibility of being utilized in wearable and foldable electronics. Here, highly stretchable conductive fiber composed ...of silver nanowires (AgNWs) and silver nanoparticles (AgNPs) embedded in a styrene–butadiene–styrene (SBS) elastomeric matrix is fabricated. An AgNW‐embedded SBS fiber is fabricated by a simple wet spinning method. Then, the AgNPs are formed on both the surface and inner region of the AgNW‐embedded fiber via repeated cycles of silver precursor absorption and reduction processes. The AgNW‐embedded conductive fiber exhibits superior initial electrical conductivity (σ0 = 2450 S cm−1) and elongation at break (900% strain) due to the high weight percentage of the conductive fillers and the use of a highly stretchable SBS elastomer matrix. During the stretching, the embedded AgNWs act as conducting bridges between AgNPs, resulting in the preservation of electrical conductivity under high strain (the rate of conductivity degradation, σ/σ0 = 4.4% at 100% strain). The AgNW‐embedded conductive fibers show the strain‐sensing behavior with a broad range of applied tensile strain. The AgNW reinforced highly stretchable conductive fibers can be embedded into a smart glove for detecting sign language by integrating five composite fibers in the glove, which can successfully perceive human motions.
Ag nanowire reinforced highly stretchable conductive fiber is developed using simple wet spinning method, which consists of silver nanowires and nanoparticles embedded in elastomeric polymer matrix. The composite fiber can preserve its electrical property under large strain and has superior strain‐sensing behavior. It can be utilized in the wearable smart glove for detecting human motions such as sign language.
This paper proposes a deep learning-based channel estimation method for multiple-input multiple-output (MIMO) systems in spatially correlated channels. To reduce the pilot overhead of pilot ...symbol-assisted channel estimation, the proposed method utilizes fewer pilot symbols than the number of transmit antennas. Firstly, based on pilot symbols, the estimated partial MIMO channel matrix, consisting of the partial coefficients of the MIMO channel matrix, is obtained by the linear minimum mean square error algorithm. After that, a deep neural network uses the estimated partial MIMO channel matrix as an input and we have the predicted MIMO channel matrix, that corresponds to the channel state information not transmitting pilot symbols. Finally, by aggregating the estimated partial MIMO channel matrix and the predicted MIMO channel matrix, the proposed method can acquire the reconstructed MIMO channel matrix. In simulation results, to show the validity of the proposed method, various performances of the proposed and conventional channel estimation methods were evaluated. Simulation results show that even though the proposed method does not send the pilot symbols for all transmit antennas, it can achieve almost the same bit error rate and improved throughput performances compared with the conventional channel estimation method.
A flexible pressure sensor with high performances is one of the promising candidates for achieving electronic skins (E‐skin) related to various applications such as wearable devices, health ...monitoring systems, and artificial robot arms. The sensitive response for external mechanical stimulation is fundamentally required to develop the E‐skin which imitates the function of human skin. The performance of capacitive pressure sensors can be improved using morphologies and structures occurring in nature. In this work, highly sensitive capacitive pressure sensors based on a porous structure of polydimethylsiloxane (PDMS) thin film, inspired on the natural multilayered porous structures seen in mushrooms, diatoms, and spongia offilinalis, have been developed and evaluated. A bioinspired porous dielectric layer is used, resulting in high‐performance pressure sensors with high sensitivity (0.63 kPa−1), high stability over 10 000 cycles, fast response and relaxation times, and extremely low‐pressure detection of 2.42 Pa. Additionally, the resulting pressure sensors are demonstrated to fabricate multipixel arrays, thus achieving successful real‐time tactile sensing of various touch shapes. The developed high‐performance flexible pressure sensors may open new opportunities for innovative applications in advanced human‐machine interface systems, robotic sensory systems, and various wearable health monitoring devices.
A highly sensitive bioinspired porous structured pressure sensor is demonstrated that can detect extremely light weight objects such as an ant. The porous structured pressure sensor is pixelated into a 15 × 15 array and based on the fast response time of the pressure sensor, real‐time tactile mapping is demonstrated under various pressures.
Superomniphobic surfaces showing extremely liquid-repellent properties have received a great amount of attention as they can be used in various industrial and biomedical applications. However, so ...far, the fabrication processes of these materials mostly have involved the coating of perfluorocarbons onto micro- and nanohierarchical structures of these surfaces, which inevitably causes environmental pollution, leading to health concerns. Herein, we developed a facile method to obtain flexible superomniphobic surfaces without perfluorocarbon coatings that have shape-tunable mushroom-like micropillars (MPs). Inspired by the unique structures on the skin of springtails, we fabricated mushroom-like structures with downward facing edges (i.e., a doubly re-entrant structure) on a surface. The flexible MP structures were fabricated using a conventional micromolding technique, and the shapes of the mushroom caps were made highly tunable via the deposition of a thin aluminum (Al) layer. Due to the compressive residual stress of the Al, the mushroom caps were observed to bend toward the polymer upon forming doubly re-entrant–MP structures. The obtained surface was found to repel most low-surface-tension liquids such as oils, alcohols, and even fluorinated solvents. The developed flexible superomniphobic surface showed liquid repellency even upon mechanical stretching and after surface energy modification. We envision that the developed superomniphobic surface with high flexibility and wetting resistance after surface energy modification will be used in a wide range of applications such as self-cleaning clothes and gloves.
Textile-based electronic components have gained interest in the fields of science and technology. Recent developments in nanotechnology have enabled the integration of electronic components into ...textiles while retaining desirable characteristics such as flexibility, strength, and conductivity. Various materials were investigated in detail to obtain current conductive textile technology, and the integration of electronic components into these textiles shows great promise for common everyday applications. The harvest and storage of energy in textile electronics is a challenge that requires further attention in order to enable complete adoption of this technology in practical implementations. This review focuses on the various conductive textiles, their methods of preparation, and textile-based electronic components. We also focus on fabrication and the function of textile-based energy harvesting and storage devices, discuss their fundamental limitations, and suggest new areas of study.
A simple method of carbonaceous films coating onto copper (Cu) nanopowder is investigated with solid carbon source. Copper nanopowder was coated with carbonaceous films using chemical vapor ...deposition (CVD) using polyvinylpyrrolidone (PVP) as a solid carbon source via a polyol method. The process time and concentration of PVP solution during the CVD process were controlled to optimize the carbonaceous films coating while preventing nanoparticles agglomeration. From TEM and FESEM, it was found that the necking among copper particles was minimum with 3 min processing time at 900 °C using 30 wt% PVP solution. TG-DTA, XPS, FT-IR and Raman analysis confirmed the successful conversion of PVP into few nanometer-thick carbonaceous films layer coating on the surface of copper nanopowder without necking. Therefore, carbonaceous films coated copper nanopowder could be applied in copper ink application for better dispersion and high stability.
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•Carbonaceous film coating onto copper nanopowder.•PVP as solid carbon source converted into carbonaceous film.•Developed highly stable and well dispersed copper ink.
Inherent defects, such as grain boundaries (GBs), wrinkles and structural cracks, present on chemical vapor deposition (CVD)-grown graphene are inevitable because of the mechanism used for its ...synthesis. Because graphene defects are detrimental to electrical transport properties and degrade the performance of graphene-based devices, a defect-healing process is required. We report a simple and effective approach for enhancing the electrical properties of graphene by selective graphene-defect decoration with Pd nanoparticles (Pd NPs) using a wet-chemistry-based galvanic displacement reaction. According to the selective nucleation and growth behaviors of Pd NPs on graphene, several types of defects, such as GBs, wrinkles, graphene regions on Cu fatigue cracks and external edges of multiple graphene layers, were precisely confirmed via spherical aberration correction scanning transmission electron microscopy, field-emission scanning electron microscopy and atomic force microscopy imaging. The resultant Pd-NP-decorated graphene films showed improved sheet resistance. A transparent heater was fabricated using Pd-decorated graphene films and exhibited better heating performance than a heater fabricated using pristine graphene. This simple and novel approach promises the selective decoration of defects in CVD-grown graphene and further exploits the visualization of diverse defects on a graphene surface, which can be a versatile method for improving the properties of graphene.
Without introducing defects in the monolayer of carbon lattice, the deposition of high-κ dielectric material is a significant challenge because of the difficulty of high-quality oxide nucleation on ...graphene. Previous investigations of the deposition of high-κ dielectrics on graphene have often reported significant degradation of the electrical properties of graphene. In this study, we report a new way to integrate high-κ dielectrics with graphene by transferring a high-κ dielectric nanosheet onto graphene. Al2O3 film was deposited on a sacrificial layer using an atomic layer deposition process and the Al2O3 nanosheet was fabricated by removing the sacrificial layer. Top-gated graphene field-effect transistors were fabricated and characterized using the Al2O3 nanosheet as a gate dielectric. The top-gated graphene was demonstrated to have a field-effect mobility up to 2200 cm2/(V s). This method provides a new method for high-performance graphene devices with broad potential impacts reaching from high-frequency high-speed circuits to flexible electronics.
Highly stretchable fiber strain sensors are one of the most important components for various applications in wearable electronics, electronic textiles, and biomedical electronics. Herein, we present ...a facile approach for fabricating highly stretchable and sensitive fiber strain sensors by embedding Ag nanoparticles into a stretchable fiber with a multifilament structure. The multifilament structure and Ag-rich shells of the fiber strain sensor enable the sensor to simultaneously achieve both a high sensitivity and largely wide sensing range despite its simple fabrication process and components. The fiber strain sensor simultaneously exhibits ultrahigh gauge factors (∼9.3 × 105 and ∼659 in the first stretching and subsequent stretching, respectively), a very broad strain-sensing range (450 and 200% for the first and subsequent stretching, respectively), and high durability for more than 10 000 stretching cycles. The fiber strain sensors can also be readily integrated into a glove to control a hand robot and effectively applied to monitor the large volume expansion of a balloon and a pig bladder for an artificial bladder system, thereby demonstrating the potential of the fiber strain sensors as candidates for electronic textiles, wearable electronics, and biomedical engineering.
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