• Journal of the Korean Society of Industry Convergence
• /
• v.5 no.2
• /
• pp.141-146
• /
• 2002

Stereolithography is the best known as rapid prototyping system. It uses the STL format data which is generated from CAD system. In this study, One of the main function of this developed CAM system deals with shape modification which divide a shape into two parts or more. The cross section of a STL part by a z-level is composed with nested or single polygonal closed loop. In order to make RP product, closed loops must fill with triangular facets from SSET and recover sliced triangular facets which is located normal direction to the cross sectional plane. The system is development by using Visuall C++ compiler in the environment of pentium PC. Operating system is Windows NT workstaion from Micro-Soft.

• Smart Structures and Systems
• /
• v.4 no.2
• /
• pp.137-152
• /
• 2008

The work presented in this paper includes material characterisation and an investigation of suitability in seismic dampers for two commercially available NiTi-alloys, along with a numerical analysis of a new damper system employing composite NiTi-wires. Numerical simulations of the new damper system are conducted, using Brinson's one-dimensional constitutive model for shape memory alloys, with emphasis on the system's energy dissipation capabilities. The two alloys tested showed some unwanted residual strain at temperatures higher than $A_f$, possibly due to stress concentrations near inclusions in the material. These findings show that the alloys are not ideal, but may be employed in a seismic damper if precautions are made. The numerical investigations indicate that using composite NiTi-wires in a seismic damper enhances the energy dissipation capabilities for a wider working temperature range.

• Transactions of Materials Processing
• /
• v.15 no.2 s.83
• /
• pp.143-147
• /
• 2006

Effect of processing condition on the hot extrusion of Al-Zn-Mg-Sc alloy was investigated. For this purpose, hot compression test and FE-simulation were conducted via Thermecmaster-Z and DEFORM-3D, respectively. The microstructure evolution during hot extrusion and post heat-treatment was investigated and deformation mechanisms were analyzed by constructing processing map. FE-simulation results show that the temperature difference between container and billet has considerable influence on the final shape of extruded T-shape bar. The relation between applied load and processing time was predicted by the FE-analysis as well as punch speed vs. stroke chart.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.10a
• /
• pp.202-205
• /
• 2005

Effect of processing condition on the hot extrusion of Al-Zn-Mg-Sc alloy was investigated. For this purpose, hot compression test and FE-simulation were conducted via Thermecmasteer-Z and DEFORM-3D, respectively. The microstructure evolution during hot extrusion and post heat-treatment was investigated and deformation mechanisms were analyzed by constructing processing map. FE-simulation results show that the temperature difference between container and billet has considerable influence on the final shape of extruded T-shape bar. The relation between applied load and processing time was predicted by the FE-analysis as well as punch speed vs. stroke chart.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.4
• /
• pp.152-162
• /
• 1996

The purpose of this study is the development of a lathe which can cut any pistons of oval shape with high speed, accuracy and precision by CNC (Computer Numerical Control) method. Y axis which is the position determinating mechanism with high speed response was added to the CNC lathe and the ovality and profile was cut under the control of C-Y-Z axes at same time. In the case of ovality of .phi. 0.2mm, the productivity can be improved up to 2500rpm(Y axis:83Hz) by high speed cutting than modeling method. Since a personal computer is used, it is easy to change the shape of pistion and can be applied promptly to many types of piston shppe by only changing data files.

• Archives of Plastic Surgery
• /
• v.38 no.4
• /
• pp.408-414
• /
• 2011

Purpose: To correct breast ptosis, reduction mammoplasty and mastopexy have been developed in a way that minimizes complications. Recently, as the mean age of breast cancer occurrence is decreasing, the need for breast reconstruction in patients with breast cancer is rising. If mastopexy is performed with breast reconstruction at the same time, the size of the normal breast and the new one is not quite different. We decided to apply Z-plasty, which is a widely-used technique in plastic surgery to lengthen or change the direction of tension of the tissue. Methods: From March 2008 to December 2009, we performed breast reconstruction in 6 patients with breast cancer and scar contracture. After breast reconstruction, mastopexy with Z-plasty was applied to correct the asymmetry. The new nipple-areolar complex is placed on the line connecting the midclavicle and the current nipple. The inferior border of the new areola corresponds with the inferior border of the original areola, and the superior border about 2 cm upward the original superior border. We drew two oblique lines connecting the medial end of the incision line lower to the nipple-areola complex and the lateral end of the inframammary fold for Z-plasty. The excess tissue between these two lines was removed and the new triangular flaps were put together. Results: The average age of patients was 42.6 years, aged from 36.1 to 48.1 The weight of removed tissue was between 54g and 95 g, with the mean of 74 g. The average distance from the midclavicle to the nipple was 24 cm before surgery, and 21 cm after the surgery. The average operation time per patient (1 mastopexy) was 45 minutes, and the patients were satisfied with the size and shape. Conclusion: Applying Z-plasty for the mastopexy on the normal breast ptosis is a relatively simple way to achieve symmetry in patients who need breast reconstruction.

• Structural Engineering and Mechanics
• /
• v.56 no.5
• /
• pp.813-833
• /
• 2015

Spherical reticulated shells are widely applied in structural engineering due to their good bearing capability and attractive appearance. Parametric modeling of spherical reticulated shells is the basis of internal analysis and optimization design. In the present study, generation methods of nodes and the corresponding connection methods of rod elements are proposed. Modeling programs are compiled by adopting the ANSYS Parametric Design Language (APDL). A shape optimization method based on the two-stage algorithm is presented, and the corresponding optimization program is compiled in FORTRAN environment. Shape optimization is carried out based on the objective function of the minimum total steel consumption and the restriction condition of strength, stiffness, slenderness ratio, stability. The shape optimization of four typical Schwedler spherical reticulated shells is calculated with the span of 30 m~80 m and rise to span ratio of 1/7~1/2. Compared with the shape optimization results, the variation rules of total steel consumption along with the span and rise to span ratio are discussed. The results show that: (1) The left and right rod-Schwedler spherical reticulated shell is the most optimized and should be preferentially adopted in structural engineering. (2) The left diagonal rod-Schwedler spherical reticulated shell is second only to left and right rod regarding the mechanical behavior and optimized results. It can be applied to medium and small-span structures. (3) Double slash rod-Schwedler spherical reticulated shell is advantageous in mechanical behavior but with the largest total weight. Thus, this type can be used in large-span structures as far as possible. (4) The mechanical performance of no latitudinal rod-Schwedler spherical reticulated shell is the worst and with the second largest weight. Thus, this spherical reticulated shell should not be adopted generally in engineering.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.5
• /
• pp.482-489
• /
• 2010

This paper describes the test procedure, instrumentation, verification methodology and the results of the ground vibration test(GVT) and force vibration test(FVT) of the SmartUAV aircraft to estimate experimentally dynamic characteristics of the aircraft. Bungee cords are used to emulate free-free boundary conditions of the test aircraft. The SmartUAV is excited by three shakers and one-hundred frequency response functions(FRF's) is measured. The FRF's are reduced and analyzed to identify the dynamics parameters of the SmartUAV. To extract modal parameters of the SmartUAV such as, natural frequencies and damping ratios, the poly-reference least square complex exponential method is used in the time domain. The mode shape coefficients are estimated with the least squares frequency domain method to identify the vibration modes. The FVT was performed by fixed sine frequency with three shakers on the x, y and z direction and vibration characteristics of structures and detail equipments are measured.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.1
• /
• pp.48.1-48.1
• /
• 2012

We present the ultraviolet (UV) color-color relation of early-type galaxies (ETGs) in the nearby universe (0.05 < z < 0.12) to investigate the properties of hot stellar populations responsible for the UV excess (UVX). The initial sample of ETGs is selected by the spectroscopic redshift and the morphology parameter from the SDSS DR 7, and then cross-matched with the GALEX far-UV (FUV) and near-UV (NUV) GR6 data. The cross-matched ETG sample is further classified by their emission line characteristics in the optical spectra into quiescent, star-forming, and active galactic nucleus categories. Contaminations from early-type spiral galaxies, mergers, and morphologically disturbed galaxies are removed by visual inspection. By drawing the FUV-NUV (as a measure of UV spectral shape) versus FUV-r (as a measure of UVX strength) diagram for the final sample of -3700 quiescent ETGs, we find that the "old and dead" ETGs consist of a well-defined sequence in UV colors, the "UV red sequence," so that the stronger UVX galaxies should have a harder UV spectral shape systematically. However, the observed UV spectral slope is too steep to be reproduced by the canonical stellar population models in which the UV flux is mainly controlled by age or metallicity parameters. Moreover, 2 mag of color spreads both in FUV-NUV and FUV-r appear to be ubiquitous among any subsets in distance or luminosity. This implies that the UVX in ETGs could be driven by yet another parameter which might be even more influential than age or metallicity.

• Biomedical Science Letters
• /
• v.7 no.4
• /
• pp.167-172
• /
• 2001

Nebulin is an approximately 700 kDa filamentous protein in vertebrate skeletal muscle. It binds to the Z line and also binds side-by-side to the entire thin actin filament in a sarcomere. The correlation of nebulin size with thin filament length have led to the suggestion that nebulin acts as a molecular ruler for the length of thin filaments. The C-terminal part of human nebulin is anchored in the sarcomeric Z-disk and contains an SH3 domain. SH3 domains have been identified in an ever-increasing number of proteins important for a wide range of cellular processes, from signal transduction to cytoskeleton assembly and membrane localization. However, the exact physiological role of SH3 domains remains, in many cases, unclear. To explore the role of nebulin SH3 in the cytoskeletal rearrangement that accompanies myoblast differentiation, we transfected sense and antisense nebulin SH3 domain fused to enhanced green fluorescent protein in myoblast. Cells expressing nebulin SH3 fragment showed decrease of cell-cell adhesion, and cells transfected with antisense nebulin SH3 gene showed a rounded cell morphology and loss of cell-matrix adhesion. No alteration in cell shape and differentiation were observed in control cells expressing enhanced green fluorescent protein. Perturbation of nebulin altered the cell shape and disrupted cell adhesion in myoblast, demonstrating that nebulin can affect cytoskeleton rearrangement.