The uniform growth of single-crystal graphene over wafer-scale areas remains a challenge in the commercial-level manufacturability of various electronic, photonic, mechanical, and other devices based ...on graphene. Here, we describe wafer-scale growth of wrinkle-free single-crystal monolayer graphene on silicon wafer using a hydrogen-terminated germanium buffer layer. The anisotropic twofold symmetry of the germanium (110) surface allowed unidirectional alignment of multiple seeds, which were merged to uniform single-crystal graphene with predefined orientation. Furthermore, the weak interaction between graphene and underlying hydrogen-terminated germanium surface enabled the facile etch-free dry transfer of graphene and the recycling of the germanium substrate for continual graphene growth.
This study investigates the role of content and noncontent cues of tourism information quality in forming users’ destination image in social media. Empirical analysis based on data collected from ...Sina Weibo users suggests that several content cues and web page design as a noncontent cue are positively related with cognitive and affective images, which lead to a conative image. This study contributes to the body of knowledge on the role of tourism information quality in social media by providing empirical evidence on destination image formation. It also helps tourism managers build their marketing strategies to attract more tourists through social media.
Colloidal metal chalcogenide quantum dots (QDs) have excellent quantum efficiency in light–matter interactions and good device stability. However, QDs have been brought to the forefront as viable ...building blocks in bottom‐up assembling semiconductor devices, the development of QD solar cell (QDSC) is still confronting considerable challenges compared to other QD technologies due to their low performance under natural sunlight, as a consequence of untapped potential from their quantized density‐of‐state and inorganic natures. This report is designed to address this long‐standing challenge by accessing the feasibility of using QDSC for indoor and concentration PV (CPV) applications. This work finds that above bandgap photon energy irradiation of QD solids can generate high densities of excitons via multi‐photon absorption (MPA), and these excitons are not limited to diffuse by Auger recombination up to 1.5 × 1019 cm−3 densities. Based on these findings, a 19.5% (2000 lux indoor light) and an 11.6% efficiency (1.5 Suns) have been facilely realized from ordinary QDSCs (9.55% under 1 Sun). To further illustrate the potential of the MPA in QDSCs, 21.29% efficiency polymer lens CPVs (4.08 Suns) and viable sensor networks powered by indoor QDSCs matrix have been demonstrated.
Quantum dots (QDs) solar cells (9.55% efficiency) for indoors (19.5% at 2000 lux) and concentration (11.6% at 1.5 Suns) photovoltaics are demonstrated. This work finds above bandgap photon energy irradiation of QD solids can generate high densities of excitons via multi‐photon absorption and these excitons are not limited to diffusion by Auger recombination up to 1.5 × 1019 cm−3 densities.
An initial coin offering (ICO) seeks to raise initial investments for companies by selling crypto tokens to individuals interested in crowdfunding. As ICOs have gained popularity, a lack of ...information regarding startup companies' prior financial status and business health has led to information asymmetry between potential investors and ICO projects. This study explores the informational cues necessary to bridge this gap. Employing signaling theory, we elucidate the presence of information asymmetry and conduct two case analyses to identify relevant informational cues. Twitter data from two ICO projects (Stratis and NEO), which achieved the highest return on investment at the time of data collection, are extracted and analyzed to identify informational themes. Our findings reveal multiple and distinctive themes of informational cues for each ICO project, demonstrating that transmitted signals vary across different stages and are generated by both the coin publisher and the public. This research illuminates the flow of informational cues between ICO initiators and potential investors on social media. By analyzing online communication threads using qualitative methods, this study significantly contributes to the understanding of information asymmetry in the context of ICOs.
Lithium (Li) metal, with its unparalleled theoretical capacity and lowest electrochemical potential, is a promising anode material for rechargeable batteries. Yet, challenges such as dendrite ...formation, severe electrode volume change, and ongoing Li consumption impede its practical adoption. To address these challenges, a novel approach is introduced, harnessing the switchable electrical conductivity of a nanoporous current collector for Li metal anode. A vertically aligned Nickel‐catecholate (VANC) is directly grown on the copper foil as the nanoporous current collector, and the Li intercalation and de‐intercalation of VANC reversibly decrease and increase the electrical conductivity in the direction perpendicular to the electrode, respectively. The switchable conductivity induces uniform deposition and stripping of Li metal without forming dendrite and dead Li during the Li plating/stripping process and thus enables high coulombic efficiency of over 98% even after 200 cycles. This nanoporous structure with switchable conductivity will open up a new path for reliable lithium metal anode for rechargeable battery applications.
Lithium (Li) intercalates between the interlayer of vertically aligned Nickel‐catecholate (VANC) and disturbs the order of (001) plane of it, leading to a thousand times increase in electrical resistance of VANC in c‐axis direction. The electrical resistance of VANC is able to decrease reversibly after Li de‐intercalation. This switchable electrical resistance of VANC alleviates Li dendrite growth and induces even Li deposition.
In spite of diverse measures by national governments and destination marketing organizations (DMOs), the statistics related to international tourist destinations, including those of independent ...travelers, show that the rankings of the most popular tourist destinations have undergone minimal changes over the past decade. The aim of this study is to understand the factors that prevent independent travelers from selecting smaller regions (i.e., relatively less popular destinations) and examine the impact of these constraint factors on destination image formation. Using both qualitative and quantitative data collected from independent travelers, this study found that intrapersonal, interpersonal, structural, and awareness constraints are the major constraint factors. Intrapersonal constraints were found to be negatively associated with the cognitive and affective image of a destination, while awareness constraints were found to be negatively associated with the cognitive image of a destination. Cognitive and affective images were also found to be significant antecedents of conative image. The study includes a discussion of theoretical and managerial implications of these findings and directions for future research.
This paper examines the potential impact of the triadic social interaction instigated by spatial distance between author, reader, and business that detects tourists' geographical decision patterns. A ...social media asset for brands is a digital presence that encourages positive consumer responses in media communication. Using 2,129 items of author-reader-business paired review data, the findings indicate that geographical proximity between the review triad has assimilated patterns to assess reviews. Spatial regression analysis visualized spatial heterogeneity across US regions, showing that a lower spatial distance between tourists and businesses positively improved media assets; in contrast, close spatial proximity had a strong impact among peer tourists. As spatially heterogeneous tourists positively accept media sharing toward the business, the review triad model imposes the varying effects of triadic spatial distance that helps tourism policymakers implement an effective location-based social media marketing strategy for the food tourism industry.
In this study, a three-dimensional compact antenna solution for the automotive industry is proposed. The antenna solution is designed to fit in a shark-fin case and is easily fabricated from a ...printed circuit board and a metal sheet with low-cost process and materials. The antenna solution covers Long Term Evolution (LTE), GPS, WLAN, and Wireless Access in the Vehicular Environment (WAVE) bands (850 MHz, 1575 MHz, 2.4 GHz, and 5.9 GHz, respectively). The planar inverted-F antennas are used as multiple-input-multiple-output antennas for the LTE band due to their low-profile structure. Modified planar monopoles are used to obtain omnidirectional radiation patterns for WLAN and WAVE bands. Antenna characteristics such as return loss, isolation, and radiation pattern have been simulated and measured to confirm the possibility for use in automotive applications.
This paper presents the design and analysis of low flicker-noise RF mixers in a 0.18-mum CMOS process for C-band direct-conversion receivers. The low flicker-noise mixers are implemented by ...incorporating a double-balanced Gilbert-type configuration, the RF leakageless current bleeding technique, and the resonating technique for the tail capacitance. First, a double-balanced Gilbert-type mixer using the current bleeding technique has been fabricated and measured for lowering flicker corner frequency. Second, a double-balanced Gilbert-type mixer using the current bleeding technique with one resonating inductor has been designed to improve conversion gain and flicker-noise performance. Third, by using two separate inductors at the node between the current bleeding device and local oscillator switches, conversion gain and flicker-noise performance are significantly improved. A conventional Gilbert-type mixer without any technique has also been fabricated and measured for comparative purposes. The Gilbert-type mixer using the current bleeding technique with two resonating inductors has a measured conversion gain of 16.1 dB, a measured input third-order intercept point of -5 dBm, a measured noise figure of 9.8 dB at 1 MHz, and a flicker corner frequency of 125 kHz while consuming only 7 mW of dc power. To the best of our knowledge, the proposed mixer shows the lowest flicker corner frequency (125 kHz) with more than 15 dB of conversion gain in the CMOS process
Stretchable and transparent thin film transistors (TFTs) with intrisically brittle oxide semiconductors are built using a wavy structural configuration that can provide high flexibility and ...stretchability. After device fabrication procedures including high temperature annealing, the oxide semiconductor‐based TFT arrays can be transferred directly to plastic or rubber substrates, without an additional device process, using transfer printing methods. This procedure can avoid some of the thermal degradation problems associated with plastic or rubber substrates by separating them from the annealing procedure needed to improve the device performance. These design and fabrication methods offer the possibility of developing a new format of stretchable electronics.
Stretchable and transparent zinc oxide thin film transistor arrays are fabricated on rubber substrates using a wavy structural configuration that can provide high flexibility and stretchability. These design and fabrication methods offer the possibility of developing a new format of stretchable electronics.
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