Showing papers by "Jung-Ju Lee published in 2011"
TL;DR: The initial results of a study on the application of a FBG sensor to measure reflected forces in MIRS environments are presented and the possibility of successful application to MIRs systems is suggested.
Abstract: Force feedback plays a very important role in medical surgery. In minimally invasive surgery (MIS), however, the very long and stiff bars of surgical instruments greatly diminish force feedback for the surgeon. In the case of minimally invasive robotic surgery (MIRS), force feedback is totally eliminated. Previous researchers have reported that the absence of force feedback increased the average force magnitude applied to the tissue by at least 50%, and increased the peak force magnitude by at least a factor of two. Therefore, it is very important to provide force information in MIRS. Recently, many sensors are being developed for MIS and MIRS, but some obstacles to their application in actual medical surgery must be surmounted. The most critical problems are size limit and sterilizability. Optical fiber sensors are among the most suitable sensors for the surgical environment. The optical fiber Bragg grating (FBG) sensor, in particular, offers an important additional advantage over other optical fiber sensors in that it is not influenced by the intensity of the light source. In this paper, we present the initial results of a study on the application of a FBG sensor to measure reflected forces in MIRS environments and suggest the possibility of successful application to MIRS systems.
43 citations
01 Nov 2011
TL;DR: The initial results of a study on the application of a FBG sensor to measure reflected forces in MIRS environments are presented and the possibility of successful application to MIRs systems is suggested.
Abstract: Force feedback plays a very important role in medical surgery. In minimally invasive surgery (MIS), however, the very long and stiff bars of surgical instruments greatly diminish force-feedback to the surgeon. In the case of minimally invasive robotic surgery (MIRS), force-feedback is totally eliminated. Previous researchers have reported that the absence of force-feedback increased the average force magnitude applied to the tissue by at least 50%, and increased the peakforce magnitude by at least a factor of two. Therefore, it is very important to provide force information in MIRS. Recently, many sensors are being developed for MIS and MIRS, but some obstacles to their application in actual medical surgery must be surmounted. The most critical problems are size limit and sterilizability. Optical fiber sensors are among the most suitable sensors for the surgical environment. The optical fiber Bragg grating (FBG) sensor in particular offers an important additional advantage over other optical fiber sensors in that it is not influenced by the intensity of the light source. In this paper, we present the initial results of a study on the application of a FBG sensor to measure reflected forces in MIRS environments and suggest the possibility of successful application to MIRS systems.
26 citations
TL;DR: In this article, the authors used periodic square-shaped dot patterns instead of random roughness via a combination of photolithography and wet chemical etching method to improve the adhesion properties between steel and epoxy layers.
Abstract: Interfacial adhesion properties between steel and epoxy layers were improved considerably by fabricating periodic square-shaped dot patterns instead of random roughness via a combination of photolithography and wet chemical etching method. Because adhesion properties are determined generally by a roughness and topography of their surfaces, several approaches have been made to control the surface roughness, topography, and energy, for example, the surface grinding via sand papers, the surface etching by acid treatments, and the surface treatments by plasma gases. Here we confirm the enhanced adhesion performance by 40% via the periodic square-shaped dot patterns compared to conventional methods. Such remarkable enhancement in the adhesion of the dot patterned steel is due to the increased cohesive fracture area and topological interlocking. We believe that this approach is very simple and truly cost-effective and can be applicable to other microelectronics and mechanical systems and will provide potential ...
21 citations
TL;DR: In this article, micro-patterns on a bonded surface of a steel substrate were fabricated then single leg bending joints with carbon fiber reinforced polymer (CFRP) and steel were manufactured by a co-curing process.
Abstract: The interface characteristic influences the strength of the adhesive joints. For this reason, there have been studies to improve the strength of the adhesive joints using various surface treatment methods. One of these methods, mechanical interlocking by surface roughness, has been known as an effective method but an analysis of the roughness effect is not easy because the roughness profile such as height, shape, and density of peaks and valleys by sandblasting, sandpaper or etching is random. In this paper, micro-patterns on a bonded surface of a steel substrate were fabricated then single leg bending joints with carbon fiber reinforced polymer (CFRP) and steel were manufactured by a co-curing process. The mechanical interlocking effect was analyzed with three-point bending tests of single leg bending joints. Experimental results show that the mechanical interlocking effect leads to material damage and energy absorption, and complicated failure characteristics occur due to the micro-patterned surface. A ...
11 citations
TL;DR: In this article, nano and micro scale surface treatment effects on adhesion strength improvement for CFRP/aluminum interfaces were investigated by chemically etched aluminum specimens were chemically etched to fabricate micro-line patterns using the process of photolithography and then anodized to form nano scale surface morphology of an aluminum oxide layer across the whole patterned area.
9 citations
TL;DR: In this article, the two-way shape memory effect was induced through a compressive shape memory cycle composed of four steps: (1) loading to maximum deformation; (2) unloading, heating, and cooling.
7 citations
TL;DR: In this paper, a novel hinge mechanism for deployment of spacecraft subsystems such as antennas, solar arrays is presented, which has not only high deployed stiffness and low deployment shock but also does not require lubrication and accurate fabrication.
Abstract: This paper presents a novel hinge mechanism for deployment of spacecraft subsystems such as antennas, solar arrays. By using Axiomatic design theory, the conceptual design of the hinge mechanism is suggested, which has not only high deployed stiffness and low deployment shock but also does not require lubrication and accurate fabrication. That is, optimization of deployment torque and maximization of the deployed stiffness can be possible since this suggested hinge mechanism is decoupled design. And the suggested hinge mechanism is fabricated and tested to evaluate the feasibility. Quasi-static analysis is performed to optimize deployment torque for low deployment shock by using FEM. Also, the bending stiffness is measured by 4 point bending test.
1 citations
30 Apr 2011
TL;DR: In this paper, the effect of loading mode on interfacial crack growth is investigated on the basis of crack path observation using microscopic image acquisition technique, and the influence of interfacial roughness on adhesion strength is also discussed.
Abstract: Interfacial fracture toughness under various mixed-mode loading is measured to provide a mixed-mode fracture criterion of a composite/metal bonded joint. Experimental fracture characterization tests were carried out using a SLB (single leg bending) specimen, which controls mode ratio with the specimen thickness. The experimental result of the SLB test conforms that interfacial fracture toughness increases as the mode II component increases. The effect of loading mode on interfacial crack growth is investigated on the basis of crack path observation using microscopic image acquisition technique. The influence of interfacial roughness on adhesion strength is also discussed.
1 citations