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In penetrating keratoplasty (PKP), the proper corneal suture placement is very important for successful transplantation and restoring functional vision. Generating sutures with accurate depth is difficult for the surgeon because of the tissue’s softness, lack of depth information, and hand tremors. In this paper, an automatic cornea grasping device is proposed, which detects when the device reaches the target suture depth. When the device reaches the target depth, the device rapidly grasps the cornea to prevent error induced by human hand tremors. In the paper, the performance of the proposed sensor, the actuator, and the device are experimentally verified with ex vivo experiment. The result showed that the proposed device could enhance the accuracy and precision of the corneal suture depth.

Two-dimensional (2D) transition metal dichalcogenides (TMDs)-based van der Waals (vdW) PN junctions have been used for heterojunction diodes, which basically utilize out-of-plane current across the junction interface. In fact, the same vdW PN junction structure can be utilized for another important device application, junction field effect transistors (JFETs), where in-plane current is possible along with 2D–2D heterojunction interface. Moreover, the 2D TMD-based JFET can use both p- and n-channel for low voltage operation, which might be its unique feature. Here we report vdW JFETs as an in-plane current device with heterojunction between semiconducting p- and n-TMDs. Since this vdW JFET would have low-density traps at the vdW interface unlike 2D TMD-based metal insulator semiconductor field effect transistors (MISFETs), little hysteresis of 0.0–0.1 V and best subthreshold swing of ~100 mV/dec were achieved. Easy saturation was observed either from n-channel or p-channel JFET as another advantage over 2D MISFETs, exhibiting early pinch-off at ~1 V. Operational gate voltage for threshold was near 0 V and our highest mobility reaches to ~>500 cm2/V·s for n-channel JFET with MoS2 channel. For 1 V JFET operation, our best ON/OFF current ratio was observed to be ~104. Van der Waals heterostructures of atomically thin semiconductors enable junction field effect transistors (JFETs). A team led by Seongil Im at Yonsei University fabricated JFETs using a heterojunction of semiconducting p-MoTe2 (or p-WSe2) and n-MoS2. The p-type transition metal dichalcogenide (TMDC) works as a gate for the n-type TMDC channel, whereas the n-type TMDC operates as a gate for the p-type TMDC channel. Owing to the low density of traps at the van der Waals interface, the devices exhibit low hysteresis of 0.05–0.1 V and achieve a subthreshold swing of ~100 mV/decade. The highest mobility reaches 500 cm2/V·s for the n-channel JFET with MoS2, whereas the p-channel JFET with MoTe2 is characterized by a much lower mobility of ~13 cm2/V·s. The highest ON/OFF current ratio was observed to be >104.

It is safe and light because it uses carbon/glass fiber reinforced plastics (hereinafter referred to as C/GFRP) through this technological development. Moreover, sunlight LED luminous bollard, which was harmonized with the surrounding environment with diverse colors, was developed. Luminous bollard can reduce its weight and also increase its strength by adjusting the intensity and thickness of a product customized for each usage on the basis of the characteristics of C/GFRP composite. In addition, C/GFRP and steel pipe were compared for the compression test in order to compare the objective rigidity. As a result, this study could obtain a positive result graph of luminous bollard. To develop luminous bollard, the composite development process was configured through a fixture of pullout and filament winding. Diverse colors can be applied to luminous bollard. Hence, it is possible to select a color customized for each region. It is also possible to create an aesthetic harmony with a surrounding environment through LED lamps at night. The pipe, which was 50 percent lighter than stainless and also which had excellent tensile strength, was designed to develop the bollard that has superior convenience in terms of construction, maintenance and repair.

The cutting characteristics of biomaterials (Ti-6Al-4V ELI) by tools are investigated with respect to cutting force, work piece surface roughness and tool flank wear by the vision system. Ti-6Al-4V ELI titanium turning is carried out with various cutting conditions; spindle rotational speed and feed rate. Back propagation neural networks (BPNs) are used for detection of tool wear. The input vectors of neural network comprise of spindle rotational speed, feed rates, vision flank wear, and cutting force signals. The output is the tool wear state which is either usable or failure. The detection of the abnormal states using BPNs achieves 97.5% reliability even when the spindle rotational speed and feed rate are changed.

New materials widely used for automobile related industry, aircraft, space development area are mostly high hardness materials. The hardness value of some hardened materials is over HRC45 and machining of this hardened materials is called as hard turning. Hard turning has its advantage on processing flexibility, cycle time and tool cost reduction. Also this process obtains high efficiency in processing and precise surface roughness through application of the CBN tools. In hard turning process with CBN tool, surface integrity is the important factor for considering the design of machine part and component under high stress and load conditions. A purpose of this study is to analyze optimal condition in hard turning process of AISI 52100 steel (HRC62) with high CBN and low CBN on turning characteristics, tool wear mechanism comparison and surface integrity.