1,721,322 research outputs found
생체 의료 적용을 위한 3D 프린팅 지지체 제작 및 표면 최적화 기술
No full textThree-dimensional (3D) printing is one of the most effective scaffold manufacturing techniques which might revolutionize the realm of tissue engineering and regenerative medicine. The scaffolds, one of the major elements of tissue engineering, along with growth factors and cells, are still one of the most promising approaches for developing organ regeneration. However, the applications of 3D-printed hard scaffolds might have limitations due to their poor surface properties, which play a crucial role in cell recruitment and infiltration, tissue-scaffold integration, and anti-inflammatory properties. Various prerequisites have been suggested for clinical applications of 3D-printed substitute for human body. Consequently, continuous amendment has been made to modify the surface properties, porosities and mechanical properties of these scaffolds. The techniques that modify the surfaces through chemical and material modifications can also be applied to facilitate the efficacy of these scaffolds. In this review, we summarized the characteristics of 3D printing technology and discuss the development direction of the latest 3D printing technology toward meeting the unmet needs in the clinic
Investigation of equivalent system modeling and dynamic characteristics using reduced models
No full textAn improved approach of updating the initial finite element models in comparison with a modal test is presented. This is accomplished by using the reduced models dynamically equivalent to the initial models. The degrees of freedom (DOF) in the reduced models include the generalized coordinates besides the measurement points for a modal test. Therefore, these reduced models can take into account the inertia force at unmeasured DOF and preserve the dynamic characteristics of the initial analytical models regardless of the measurement points. These reduced models are used for a direct analysis/experiment correlation with modal test data. Numerical simulation results are presented to show the effectiveness of these reduced models in the parametric correction of the analytical finite element models
Control of nonlinear singularly perturbed systems using gain scheduling
No full textIn this paper we analyze an asymptotic stability of nonlinear singularly perturbed systems and propose a composite control with gain scheduling where the fast controller is the gain scheduled controller and the slow state plays a role of slowly varying parameters in gain scheduling. Specifically, the slow controller is designed by the slow manifold to stabilize the reduced slow system. As a result, the slow manifold of the system is the same as the designed manifold
Beam combination characteristics in an array laser using stimulated Brillouin scattering phase conjugate mirrors considering partial coherency between the beams
No full textBeam combination characteristics were numerically and experimentally investigated in an array laser amplification using stimulated Brillouin scattering (SBS) phase conjugation. To clarify the effect of piston errors due to imperfect phase locking, spatial intensity profiles of the beam combination output were calculated in both the near and the far field on the basis of the Rayleigh-Sommerfeld diffraction theory. The analyses indicate that piston errors are seriously detrimental to the quality of a beam combination output and should be eliminated by a proper phase locking. To estimate the relationship between the output beam brightness and partial phase locking due to back-seeding, a statistical calculation with a root-mean-square (RMS) criterion method was used. Enhanced brightness was obtained with only partial phase locking. Basic experimental results are also presented and show the same tendency to numerical results. (C) 1999 Elsevier Science S.A. All rights reserved
Dual-band internal WLAN antenna for 2.4/5 GHz laptop PC applications
No full textThis paper presents a dual-band internal WLAN PIFA for 2.4/5 GHz laptop applications in consideration of the influences of laptop housing and LCD. The prototype antenna is modified when installed along the perimeter of the display panel of the laptop housing. The proposed antenna has a small ground plane and achieves an impedance bandwidth of 250 MHz (2.37-2.62 GHz) in Bluetooth band and 950 MHz (4.98-5.93 GHz) near 5 GHz in WLAN band within 2:1 voltage standing wave ratio (VSWR). It also shows good antenna gain with small volume. These features make it an alternative for use in dual-band WLAN antennas. Design details for the proposed antenna in the case of the antenna itself and the application of laptop PC housing are described, and experimental results of the antenna achievements are investigated and discussed. (c) 2006 Wiley Periodicals, Inc
A broadband interior antenna of planar monopole type in handsets
No full textA novel internal antenna of planar monopole type is presented for broadband applications. The proposed antenna fed by a 50-Omega microstrip line covers the digital cordless system (DCS, 1710-1880 MHz), personal communication system (PCS, 1750-1870 MHz), and international mobile telecommunication (IMT-2000, 1885-2200 MHz) bands within S-11 < - 10 dB. The antenna occupies a compact volume of 20 x 17 x 4.7 mm(3) and it is suitable to be built-in within the housing of a mobile phone. The bandwidth of the proposed antenna (VSWR < 2) has 740 MHz starting from 1620 to 2360 MHz. The IE3D software and microwave studio (MWS) simulation are employed for optimizing the design parameters, and the simulation results are in agreement with those of the measured one, considering each associated case of the antenna itself, phone case, and battery
Surface Strengthening of Alumina-Zirconia Composite by Addition of Molybdenum Dioxide
No full textMoO2 is found to stabilize m-ZrO2. Because of the addition of MoO2 into ZrO2 at the surface region of an Al2O3-15 vol% ZrO2 composite, the volume fraction of m-ZrO2 at the surface increases from 0.3 to 0.5-0.6 without changing the size of the ZrO2 grains. This enhanced transformation results in an increase in flexural strength of up to 30% because of compressive stresses built in at the surface. The increase in flexural strength is proportional to the difference in volume fraction of m-ZrO2 between the surface layer and the bulk matrix, in agreement with a previous analysis
Recent Advances in Allergen-Specific Immunotherapy in Humans: A Systematic Review
Get PDFAllergen-specific immunotherapy (AIT) is presumed to modulate the natural course of allergic disease by inducing immune tolerance. However, conventional AITs, such as subcutaneous immunotherapy and sublingual immunotherapy, require long treatment durations and often provoke local or systemic hypersensitivity reactions. Therefore, only <5% of allergy patients receive AIT as second-line therapy. Novel administration routes, such as intralymphatic, intradermal and epicutaneous immunotherapies, and synthetic recombinant allergen preparations have been evaluated to overcome these limitations. We will review the updated views of diverse AIT methods, and discuss the limitations and opportunities of the AITs for the treatment of allergic diseases in humans
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