Investigation of Cation Exchange Behaviors of FA\u3csub\u3ex\u3c/sub\u3eMA\u3csub\u3e1-x\u3c/sub\u3ePBl\u3csub\u3e3\u3c/sub\u3e Films Using Dynamic Spin Coating

In this study, we fabricated and characterized uniform multi-cation perovskite FAxMA1−xPbI3 films. We used the dynamic spin-coating method to control the cation ratio of the film by gradually increasing the FA+, which replaced the MA+ in the films. When the FA+ concentration was lower than xFA ~0.415 in the films, the stability of the multi-cation perovskite improved. Above this concentration, the film exhibited δ-phase FAPbI3 in the FAxMA1−xPbI3 films. The formation of δ-phase FAPbI3 disturbed the homogeneity of the photoluminescence spatial distribution and suppressed the absorption spectral bandwidth with the increasing bandgap. The precise control of the cation ratio of multi-cation perovskite films is necessary to optimize the energy-harvesting performance

Tip-Enhanced Raman Scattering Imaging of Two-Dimensional Tungsten Disulfide with Optimized Tip Fabrication Process

We successfully achieve the tip-enhanced nano Raman scattering images of a tungsten disulfide monolayer with optimizing a fabrication method of gold nanotip by controlling the concentration of etchant in an electrochemical etching process. By applying a square-wave voltage supplied from an arbitrary waveform generator to a gold wire, which is immersed in a hydrochloric acid solution diluted with ethanol at various ratios, we find that both the conical angle and radius of curvature of the tip apex can be varied by changing the ratio of hydrochloric acid and ethanol. We also suggest a model to explain the origin of these variations in the tip shape. From the systematic study, we find an optimal condition for achieving the yield of similar to 60% with the radius of similar to 34 nm and the cone angle of similar to 35 degrees. Using representative tips fabricated under the optimal etching condition, we demonstrate the tip-enhanced Raman scattering experiment of tungsten disulfide monolayer grown by a chemical vapor deposition method with a spatial resolution of similar to 40 nm and a Raman enhancement factor of similar to 4,760. © The Author(s) 2017

Study on the Usefulness of Sit to Stand Training in Self-directed Treatment of Stroke Patients

Abstract. [Purpose] This study sought to determine the usefulness of sit to stand training in self-directed treatment of stroke patients. It examined the effect that sit to stand training has on balance and functional movement depending on the form of support surfaces. [Subjects and Methods] Thirty stroke patients were randomly sampled and divided into an unstable support surface group (15) and stable support surface group (15). In order to identify the effect depending on the form of support surfaces, 15 minutes of support surface training plus + 15 minutes of free gait training was performed. [Results] The results of the unstable support surface training showed that the corresponding sample t-test results were significant for the 7-item 3-point Berg balance scale, timed Up and Go test, and 6-minute walking test. The independent samples t-test, showed that there were significant outcomes in step length on the affected side, and step length on the unaffected side. [Conclusion] In conclusion, the sit to stand training on stable support surfaces was not as effective as the training using unstable support surfaces, but it is a simple and stable exercise with less risk of falls during training. It can also be performed alone by the patient in order to increase endurance and dynamic balance ability. Therefore, it is considered a useful exercise that can be performed alone by the patient outside the treatment room