Cationic-exchange methods allow for the fabrication of metastable phases or shapes, which are impossible to obtain with conventional synthetic colloidal methods. Here, we present the systematic fabrication of heteronanostructured (HNS) Cu 2−x S@CuInS 2 nanodisks via a cationic-exchange reaction between Cu and In atoms. The indium−trioctylphosphine complex favorably attacks the lateral (16 0 0) plane of the roxbyite Cu 2−x S hexagon. We explain the phenomena by estimating the formation energy of vacancies and the heat of reaction required to exchange three Cu atoms with an In atom via density functional theory calculations. In an experiment, a decrease in the amount of trioctylphosphine surfactant slows the reaction rate and allows for the formation of a lateral heterojunction structure of nanoplatelets. We analyze the exact structures of these materials using scanning transmission electron microscopy−energy dispersive X-ray spectroscopy and high-resolution transmission electron microscopy. Moreover, we demonstrate that our heteronanodisk can be an intermediate for different HNS materials; for example, adding gold precursors to a Cu 2−x S@CuInS 2 nanodisk results in a AuS@CuInS 2 nanodisk via an additional cationic reaction between Cu ions and Au ions.

realistic colors can be expressed, and the contrast can be deepened, giving a 3D immersive experience. [1] To implement higher resolution quality displays, the pixel size should be more compact and smaller. Therefore, quantum dots with only a few nanometers of particle size are very suitable for the purpose. In particular, among the quantum dots, perovskite quantum dots (PeQDs) have high quantum efficiency and narrow emission spectra (full width at half maximum, FWHM) due to low trap density, and as a result, can express more realistic colors with high color reproducibility. [2] For these reasons, PeQDs have been in the spotlight as promising next-generation display materials. Perovskites generally have an ABX 3 chemical composition and their structure and stability can be predicted by calculating the Goldschmidt tolerance factor with ionic radius. [3][4][5][6] They also have the advantages of easy color tuning through halide exchange and very short synthesis time. [7,8] Currently, perovskites have been studied in depth from bulk to nanomaterials because of their wide range of applications such as LEDs, [4,9,10] solar cells, [11][12][13] lasers, [14][15][16] sensors, [17][18][19] and other applications. However, perovskites have suffered from the serious problem of low stability because structures with the ABX 3 form have weak ionic bonds and easily decompose through moisture, heat, or light exposure. [20] Unlike general semiconductor quantum dots including CdSe [21] and InP, [22] it is difficult to build a shell on the perovskite surface. Considerable research on perovskite stability has been in progress to address these issues. Recently, Li et al. fabricated CsPbBr 3 PeQD silica/ alumina monoliths through the sol-gel reaction using inorganic precursors. [23] In addition, Sun et al. showed that the photoluminescence of PeQD synthesized using octylphosphonic acid (OPA) remained in the ambient atmosphere for 3 d. [24] Herein, we synthesized PeQDs using zinc halide (ZnX 2 ) and trioctylphosphine-oxide (TOPO) as surface capping agents to improve the stability of PeQDs. The use of ZnX 2 as a precursor has already been reported. First, Jeong et al. used ZnX 2 as a halide precursor for PeQDs and explained that the stability of the PeQDs was enhanced by the halide on the surface. [25] They Perovskite is a very promising material that is being extensively studied at the bulk and nanosize scales because it has outstanding optical properties, including high quantum efficiency and narrow emission spectra. However, perovskite has stability issues related to heat, air, and light. To overcome these, highly stable perovskite quantum dots (PeQDs) are developed using excess Zn precursor and trioctylphosphine-oxide (TOPO). In particular, it is clarified that Zn and TOPO are combined and these complexes are attached to the surface of the PeQDs through 31 P NMR. They not only have high quantum efficiency and sharp full width at half maximum values (15-30 nm) but also have improved long-term stability at high temperature. Additionall...

Graphene composites with metal or metal oxide nanoparticles have been extensively investigated owing to their potential applications in the fields of fuel cells, batteries, sensing, solar cells, and catalysis. Among them, much research has focused on supercapacitor applications and have come close to realization. Composites include monometal oxides of cobalt, nickel, manganese, and iron, as well as their binary and ternary oxides. In addition, their morphological control and hybrid systems of carbon nanotubes have also been investigated. This review presents the current trends in research on metal oxide/graphene composites for supercapacitors. Furthermore, methods are suggested to improve the properties of electrochemical capacitor electrodes.

No abstract

No abstract

BackgroundThe trend toward patient- or consumer-centered healthcare has been accelerated by advances in technology, consumer empowerment, and a shift from infectious to chronic diseases. The purpose of this study was to examine the growing self-care market by analyzing self-care patterns.MethodsWe conducted a cross-sectional, web-based survey involving adults from nine major cities in the UK, the USA, Australia, and Japan. This study examined the extent and frequency of self-care, self-care expenditure, sources of self-care information, and reasons for self-care in each country.ResultsThe results showed that the prevalence of self-care was highest in Japan (54.9%), followed by the UK (43.1%), the USA (42.5%), and Australia (40.4%). The primary reason for practicing self-care was “to manage my healthcare myself” (cited by 45.7%, 59.5%, 49.2%, and 4.1% of participants in Australia, Japan, the UK, and the USA, respectively). Significant linear associations were observed between age and the prevalence of self-care in all countries (p < 0.05), indicating that self-care prevalence decreased with age in the UK, the USA, and Australia, and increased with age in Japan. The frequency with which self-care was practiced was positively correlated with age in the USA (p < 0.05), Australia (p < 0.01), and Japan (p < 0.05). In addition to acquaintances, internet search engines and information obtained from pharmacies were considered reliable and widely used sources of self-care information.ConclusionWhen developing self-care products or services, healthcare providers and policymakers should consider self-care patterns.

This study was conducted to develop a simulation model of a 120 kW class electric all-wheel-drive (AWD) tractor and verify the model by comparing the measurement and simulation results. The platform was developed based on the power transmission system, including batteries, electric motors, reducers, wheels, and a charging system composed of a generator, an AC/DC converter, and chargers on each axle. The data measurement system was installed on the platform, consisting of an analog (current) and a digital part (rotational speed of electric motors and voltage and SOC (state of charge) level of batteries) by a CAN (controller area network) bus. The axle torque was calculated using the current and torque curves of the electric motor. The simulation model was developed by 1D simulation software and used axle torque and vehicle velocity data to create the simulation conditions. To compare the results of the simulation, a driving test using the platform was performed at a ground speed of 10 km/h in off- and on-road conditions. The similarities between the results were analyzed using statistical software and we found no significant difference in axle torque data. The simulation model was considered to be highly reliable given the change rate and average value of the SOC level. Using the simulation model, the workable time of driving operation was estimated to be about six hours and the workable time of plow tillage was estimated to be about 2.4 h. The results showed that the capacity of the battery is slightly low for plow tillage. However, in future studies, the electric AWD tractor performance could be improved through battery optimization through simulation under various conditions.

BackgroundThe purpose of this study is to investigate the prevalence and utilization pattern of complementary and alternative medicine (CAM) administered by oneself or by non-institutional practitioners in a general population in South Korea.MethodsNationwide, face-to-face surveys were conducted from September 1, 2011 to October 5, 2011. We conveniently selected the participants by using a proportional allocation method according to age, gender, and region. The use of CAM in the last year, the patterns of use, sources of information, and counseling objects were investigated in addition to respondents’ demographic characteristics.ResultsAmong the 1284 people approached, 915 respondents (71.3%) reported having had at least one CAM therapy during the past 12 months. Natural products were used the most frequently (58.8%). Unexpectedly, 82.6% out of 1740 therapies reported were self-administered CAM. Healthcare professionals were the source of information on CAM in only 5.6% of all instances of use, and only 17.7% of participants had consulted with doctors regarding CAM use.ConclusionsOwing to the widespread use of CAM in South Korea, researchers should focus on the safety and potential effectiveness of CAM therapy when self-administered by users or by unauthorized CAM practitioners.