Chemically Recyclable Conjugated Polymer and One-Shot Preparation of Thermally Stable and Efficient Bulk-Heterojunction from Recycled Monomer

Recyclable conjugated polymers are important for realizing eco-friendly electronics with advantages of solution processability and flexibility. A recyclable conjugated polymer, PY-TIP is developed, of which a key monomer is successfully extracted via a mild depolymerization process and is reused for the synthesis of novel conjugated polymers. One-shot preparation of polymer acceptor and its bulk-heterojunction (BHJ) is demonstrated from the recycled monomer, Y5-TA, for the first time and the resulting BHJ film shows optimal nanoscale morphology for efficient charge generation and transport. As a result, the solar cells prepared using the BHJ film show a higher efficiency of 13.08% and much improved thermal and mechanical stability compared with those based on the small molecular acceptor. These results are important in that the various polymers can be prepared from the recycled monomer in a solid state without organic solvents and purification step and this strategy is effective for improving the thermal and mechanical stability of the BHJ film as well as achieving high photovoltaic performance. PY-TIP is exemplary in that it can reproduce its monomer which can be used to synthesize conjugated polymers with novel chemical structures and physical properties. This work provides a design guideline for developing recyclable conjugated polymers with dynamic covalent bonds.     

Detection method for genetically modified potato using an ultra-fast PCR system

Food Science and Biotechnology - Genetically modified (GM) potatoes having resistance to insects and viral diseases, low reducing sugar contents, and black spots for high quality continue to be...     

Effect of different cooking method on vitamin E and K content and true retention of legumes and vegetables commonly consumed in Korea

Food Science and Biotechnology - This study investigated the effect of cooking method on the content and true retention of vitamin E and K in legumes and vegetables, which are commonly consumed in...     

Impermeable Graphene Skin Increases the Heating Efficiency and Stability of an MXene Heating Element

A Joule heater made of emerging 2D nanosheets, i.e., MXene, has the advantage of low-voltage operation with stable heat generation owing to its highly conductive and uniformly layered structure. However, the self-heated MXene sheets easily get oxidized in warm and moist environments, which limits their intrinsic heating efficiencies. Herein, an ultrathin graphene skin is introduced as a surface-regulative coating on MXene to enhance its oxidative stability and Joule heating efficiency. The skin layer is deposited on MXene using a scalable solution-phased layer-by-layer assembly process without deteriorating the excellent electrical conductivity of the MXene. The graphene skin comprises narrow and hydrophobic channels, which results in ≈70 times higher water impermeability of the hybrid film of graphene and MXene (GMX) than that of the pristine MXene. A complementary electrochemical analysis confirms that the graphene skin facilitates longer-lasting protection than conventional polymer coatings owing to its tortuous pathways. In addition, the sp² planar carbon surface with a low heat loss coefficient improves the heating efficiency of the GMX, indicating that this strategy is promising for developing adaptive heating materials with a tractable voltage range and high Joule heating efficiency.     

Evaluating View Management for Situated Visualization in Web-based Handheld AR

As visualization makes the leap to mobile and situated settings, where data is increasingly integrated with the physical world using mixed reality, there is a corresponding need for effectively managing the immersed user's view of situated visualizations. In this paper we present an analysis of view management techniques for situated 3D visualizations in handheld augmented reality: a shadowbox, a world-in-miniature metaphor, and an interactive tour. We validate these view management solutions through a concrete implementation of all techniques within a situated visualization framework built using a web-based augmented reality visualization toolkit, and present results from a user study in augmented reality accessed using handheld mobile devices.     

Visualization for Explanation of Deep Learning-Based Defect Detection Model Using Class Activation Map

Recently, convolutional neural network (CNN)-based visual inspection has been developed to detect defects on building surfaces automatically. The CNN model demonstrates remarkable accuracy in image data analysis; however, the predicted results have uncertainty in providing accurate information to users because of the “black box” problem in the deep learning model. Therefore, this study proposes a visual explanation method to overcome the uncertainty limitation of CNN-based defect identification. The visual representative gradient-weights class activation mapping (Grad-CAM) method is adopted to provide visually explainable information. A visualizing evaluation index is proposed to quantitatively analyze visual representations; this index reflects a rough estimate of the concordance rate between the visualized heat map and intended defects. In addition, an ablation study, adopting three-branch combinations with the VGG16, is implemented to identify performance variations by visualizing predicted results. Experiments reveal that the proposed model, combined with hybrid pooling, batch normalization, and multi-attention modules, achieves the best performance with an accuracy of 97.77%, corresponding to an improvement of 2.49% compared with the baseline model. Consequently, this study demonstrates that reliable results from an automatic defect classification model can be provided to an inspector through the visual representation of the predicted results using CNN models.     

3D reconstruction considering calculation time reduction for linear trajectory shooting and accuracy verification with simulator

Artificial Life and Robotics - Photogrammetry is a three-dimensional (3D) reconstruction from images. In photogrammetry, when each image captures the features of the target object for 3D...     

Balancing control of a single-wheel inverted pendulum system using air blowers: Evolution of Mechatronics capstone design

Inverted pendulum systems are one of typical control systems suitable for cross-disciplinary education. This article delivers the historical evolution of inverted pendulum systems as Mechatronics capstone design projects for undergraduate students. A wheeled inverted pendulum system is quite a challenging and interesting system to appeal students as a design project. Several design examples from two-wheel to one-wheel inverted pendulum system are elaborated. As a current design, a one-wheel inverted pendulum system which is our main contribution, is presented to deliver novel ideas of using air power to balance the system. The roll angle is regulated by air pressure generated from ducted fans while the pitch angle is controlled by a dc motor. Air pressure is controlled by linear control methods to keep the balancing in the roll direction. Experimental studies demonstrate the successful balancing performance.