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Focused ion beam-induced displacive phase transformation from austenite to martensite during fabrication of quenched and partitioned steel micro-pillar
We report evidence of a displacive phase transformation from retained austenite to martensite during preparation of quenched and partitioned steel micro-pillars by using a focused ion beam (FIB) technique. The BCC phase produced by the FIB damage was identified as martensite. The invariant-plane strain surface relief associated with the martensitic transformation was observed in the retained austenite phase immediately after a FIB scan of the surface with the Ga+ ion beam. Use of a low acceleration voltage appears to lower the probability of the phase transformation, while a decrease of the acceleration voltage will result in an increase of the total milling time required to prepare a micro-pillar. This report addresses challenges related to the preparation of austenite micro-pillars by a conventional FIB technique. Published by Elsevier B.V
Multi-responsive albumin-lonidamine conjugated hybridized gold nanoparticle as a combined photothermal-chemotherapy for synergistic tumor ablation
Herein, we developed a multifunctional nanoplatform based on the nanoassembly of gold nanoparticles (GNP) conjugated with lonidamine (LND) and aptamer AS1411 (AS-LAGN) as an effective cancer treatment. Conjugating AS1411 aptamer on the surface of the nanoparticle significantly improved particle accumulation in cancer cells via specific affinity toward the nucleolin receptors. In vitro study clearly revealed that laser irradiation-based hyperthermia effect enhanced the chemotherapeutic effects of LND. Combinational treatment modalities revealed significant apoptosis with higher cell killing effect due to increased ROS production and inhibition of cell migration. GNP's ability to convert the excited state photon energy into thermal heat enabled synergistic photothermal/chemotherapy with improved therapeutic efficacy in animal models. Moreover, immunohistochemistry staining assays confirmed the ability of ASLAGN to induce cellular apoptosis/necrosis and ablation in tumor tissues, without causing evident damages to the surrounding healthy tissues. Altogether, this AS-LAGN nanoplatform could be a promising strategy for mitochondria-based cancer treatment.
Statement of significance
We have designed a facile biodegradable multifunctional nanocarrier system to target the mitochondria, the major "power house" of the cancer cells. We have constructed a multifunctional nanoassembly of protein coronated gold nanoparticles (GNP) conjugated with lonidamine (LND) and aptamer AS1411 (ASLAGN) as an effective combination of phototherapy with chemotherapy for cancer treatment. The LND was conjugated with albumin which was in turn conjugated to GNP via redox-liable disulfide linkage to generate oxidative stress and ROS to kill cancer cells. GNP's ability to convert the excited state photon energy into thermal heat enabled synergistic photothermal/chemotherapy with improved therapeutic efficacy in animal models. Consistently, AS-LAGN showed enhanced antitumor efficacy in xenograft tumor model with remarkable tumor regression property. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.This research was supported by a grant from the National Research Foundation of Korea (NRF), funded by the Korea government (MSIP) (No. 2018R1A2A2A05021143 and 2018R1D1A1A02085586), and by the Medical Research Center Program (2015R1A5A2009124 and 2018R1A5A2025272) through the NRF funded by MSIP
From civic to citizenship education: Toward a stronger citizenship orientation in the Ethiopian CEE curriculum
Recent research on Civic and Ethical Education (CEE) in Ethiopia has revealed a need for improvement in a number of areas with regard to the current CEE curricula. These materials are currently oriented to a conservative form of civic education than on citizenship education, whose aims are more progressive. The essential problem identified in the present study is that CEE content does not match the Ethiopian Ministry of Education’s stated goals for CEE, including the promotion of global citizenship. An inductive method was used to categorize themes found in the CEE curricula and textbook, which were analyzed with reference to Tawil’s (2013) framework for education for global citizenship. A concept in textual analysis known as ‘internal critique’ was also utilized to identify inconsistencies in the materials between the stated aims of the CEE program and the textbook content itself. The analysis revealed three main characteristics of the CEE textbooks, namely, an emphasis on sovereignty, patriotism, and responsibility; ambivalence to Ethiopia’s independence from/dependence on wealthier nations, and abstraction in CEE content. This content does only partially match the Ethiopian government’s stated aims for CEE. The findings of this study suggest that the content of the ethical dimension of Ethiopia’s CEE curriculum could be greatly improved through the inclusion of content that reflects an emphasis on citizenship education. Such an approach is more progressive than civic education and promotes a more learner-centered and critical orientation to ethical issues on the part of students within the framework of Global Citizenship Education (GCE)
Numerical simulation of a multi-port differential mobility analyzer(MP-DMA) used in a real-time nano-particle sizer (NPS)
In a recently conducted study, we developed a nano-particle sizer (NPS) that consists of a multi-port differential mobility analyzer (MP-DMA) and two multi condensation particle counters (M-CPCs) for achieving fast measurements of aerosol particles; however, the performance of MP-DMA was not detailed in the study. Therefore, the objective of this study is to perform numerical simulations to obtain the transfer function of each port in the MP-DMA, which is the main component of the NPS. We observed good agreement between the numerically obtained central particle size of each port and the experimental data under the same operating conditions. The transmission probability and resolution of each port were determined and analyzed under various conditions using the transfer function. The findings of this study shall help in understanding the advantages of NPS.This work was supported by the research fund of Hanyang University (HY-2019-P)
Extensive evaluation and classification of low‐cost dust sensors in laboratory using a newly developed test method
An extensive evaluation of low-cost dust sensors was performed using an exponentially decaying particle concentration. A total of 264 sensors including 27 sensors with light-emitting diodes (LEDs) and 237 sensors with laser lighting sources were tested. Those tested sensors were classified into 4 groups based on the deviation from the reference data obtained by a reference instrument. The response linearities of all the tested samples for PM1, PM2.5, and PM10 were in excellent agreement with the reference instrument, except a few samples. For the measurements of PM1 and PM2.5, the lighting source, that is, LED or laser, did not show any significant difference in overall sensor performance. However, LED-based sensors did not perform well for PM10 measurements. The 32, 24, and 16% of all the tested sensors for PM1, PM2.5, and PM10 measurement, respectively, are in the category of Class 1 (reference instrument reading +/- 20%) requirement. The performance of the low-cost dust sensors for PM10 measurement was relatively less satisfactory.The Ministry of Trade, Industry & Energy (MOTIE, Korea)
Integrative taxonomy of interstitial asellote isopods (Crustacea, Isopoda) from the Western Pacific region
There have been a very few extensive studies on the interstitial asellote isopods,
despite them being a evolutionarily highly successful group which is highlighted
by the species geographical distribution in various interstitial habitat from sand
beaches, freshwater and also in groundwater. It is, however, essential studying an
interstitial asellotes as key elements to understand on the colonization of both deep
sea and freshwater water groups. In this respect, the family Lepidocharontiodae,
Janiridae and Microcerberidae may provide suitable model to answer such
evolutionary and biogeographical questions. For this PhD thesis, selected asellote
isopods of the interstitial environment in the Western Pacific region were studied.
Taxonomic description of new species, their morphological variation, genetic
diversity, and a new systematic rearrangement were mainly discussed. To address
this issues, I employed several analytical methods, such as population genetics and
new techniques for geometric morphometric analysis, as well as a classical
taxonomic observation. As a result, new species of interstitial asellotes including
Lepidocharontidae, Janiridae and Mcirocerberidae were described. Moreover, two
genetically diverged lineages of Coxicerberus fukudai and its morphological
variation could be observed from the populations of East Asia. Finally, the new
systematic position of the Microcerberidae were proposed represented by the close
relationship with the freshwater asellote, Aselloidea revealed by two nuclear
ribosomal DNA.Docto
��������������� ��������������� ������������ ������ ��������� ������������ ������������ ������ N-CADIS ��������� ������
������ ��������������� ��������� ��������� ��������������� ������ ������������ ��������������� ��������������� ��������� ������ ������������ ������. ������ ��������� ������������ 0 ��������� ������ ������������ CADIS ��������� ������������ ������. ��������� CADIS ��������� ������ ��������� ��������� ������������ ��������� ��������������� ��������� ��������� ��������� ������. ������ ������ ��������� ��������� ��������������� ������ ������������ ������������ ������ ������ FW-CADIS ��������� ������ ������ ��������� ������ ��������� ��������� ������.
��� ��������������� ������ ������������ ������ ��������� ������ ��� ������ ��������� ��������������� ��������������� ��������� ���������������. ������ ������ ��������� ������ ��������� ������ ��������� ��� ��� ������ ��������������� ���������������, ��������������� ��������� ��������� ��������������� ������������ ��������������������� ������������ ��������������� ��������� ������ ��������� ��������� ������ ��������� ���������������. ��� ��������������� ��������� ��������� ������������ ��������������� N-CADIS ��������� ������ ���������. ��������� ��������� ������������ ������������ ������ ������������ ��������� ������������ ��������� ������������ ��������� ��������� ��������� ��� ������. ��������� ��������� ������������ ��������� ������������ ��������� ���������������(Adjoint Flux) ��������������� ������������ ADVANTG ��������� ���������������. N-CADIS ��������� ��������� ������������ ������ ��������� ������������ ��������� ������������ ������������ ��������� ��������� ��������� ��������� ���������������, N-CADIS ��������� ��������������� ��������� ������ ��������������� ������ ���������������. ������ ��������� ��������������� ��������������� ��������� N-CADIS ��������� FW-CADIS ��������� ������������ ������ ��������� ���������������. ��� ������ ��� ������������ ��������� N-CADIS ��������� ������������ ������������ ������������ FW-CADIS ������������ ������������ ������ ������ ������ ������ ��� ������ ��������� ���������������. ��������� ��� ������������ ��������� ��������� ������������������ ��������� ��������� ��������� ��������������� ������������ ��� ��� ��������� ������������ ��������������� ��������� ������ ��� ��� ������ ��������� ������������.Nowadays, hybrid Monte Carlo method is widely used to increase calculation efficiency of Monte Carlo simulation. For a single response problem, the Consistent Adjoint Driven Importance Sampling (CADIS) method, which uses a zero variance solution, is developed. For the inclusion of multiple responses, several methods have been proposed. Among them, the Forward-Weighted CADIS (FW-CADIS) method shows the best performance. In this study, a new hybrid Monte Carlo method, referred to as an Nth-order multi-response CADIS method (N-CADIS) is proposed for a more uniformly low variance. The objective function of the N-CADIS method is defined for weighting the responses having a higher relative error than that of the others. This property is confirmed by using the normal distribution. However, the N-CADIS method is analyzed that many adjoint calculations are needed to find maximum values. Hence the overall efficiency can be decreased. To avoid many deterministic calculations, the adjoint transport process was modified and implemented in ADVANTG code. This process produces a variance reduction parameter similar to that used in the N-CADIS method.
For verification of the unmodified N-CADIS method, it is applied to simple problems and compared with the existing methods. These results show that the N-CADIS method can produce a better efficiency only for the Monte Carlo calculation.
To verify the modified transport process, three test problems is also solved and compared with the FW-CADIS method. The results from the N-CADIS method have more uniform and lower relative error than those from the FW-CADIS method. Therefore, it is expected that the N-CADIS method will contribute to efficient calculations for a multiple responses problem in the hybrid Monte Carlo simulations.Docto
Axial vibration reduction of a wall-mounted drum-type washing machine
We proposed a mounting device for a wall-mounted drum-type washing machine in order to reduce the axial vibration transmitted to the wall by utilizing finite element analysis, and the performance of the proposed design was verified by a vibration experiment. The finite element model (FEM) was divided into the rotor and stator parts, and the axial vibration of the wall-mounted drum-type washing machine was calculated by applying the reaction force generated by the rotor parts to the stator parts. The rotating unbalanced mass, or the laundry, was applied to the FEM of the rotor parts, and the reaction force was calculated at the bearings in the rotary coordinate system. The reaction force of the rotor parts, which was converted from the rotary coordinate system to the global coordinate system, was applied to the FEM of the stator parts. The vibration of a motor was applied by measuring the vibration of the bolts connecting the motor and the tub. A vibration experiment was performed to verify the FEM with an accelerometer, tachometer, and signal analyzer. The proposed design was developed using viscoelastic rubber ethylene propylene diene monomer (EPDM) through finite element analysis, and its performance was verified by the vibration experiment. From the results of the performance evaluation, it was confirmed that the vibration reduction ratio of the maximum amplitude, rotor, and motor vibration were 29.0 %, 2.9 %, and 43.1 %, respectively.Maste
Beam profile tailoring and efficient frequency conversion of high power solid state lasers
��������� ������������ ���������, ������, ������ ��� ������ ������ ��� ��������� ������������ ��������� ��������� ���������, ��������� ��������������� ������ ��������� ������, ������, ������������ ��������� ������ ��������� ������ ��� ��������� ������ ������ ������ ��� ��������� ��� ��������� ��������� ������ ������. ��� ��������� ��������������������� ������������ ��������� ��������� ��������� ��������������� ��������� ������ ��������������������� ��������� ��� ��������� ������ ��������������� ������������ ������������������ ������������-������������(Hermite-Gaussian, HG) ��������� ���������-������������(Laguerre-Gaussian, LG) ��������� ������. ������������������ ������ ��������� ��� ��������� ������������������ ������ ��� ��������� ��������� ������ ��������� ��������� ��������������� ��������� ��� ��������� ������������ ��������� ������������ ������������ ��������������� TEM00 ��������� ��������������� ������ ���������������. ��������� ��������������� ��������� ���������-������������ ��������� ������������ ��������� ��������� ��������� ������ ��� ������ ������ ��������� HG ������ ������ ������������ ������ ��������� ��� ������ ��������� ��������� ��������� ������ ��������� ������ ��������� ������ ������ ��������� ��������� ������, ���������/��������� ������ ��� HG ������ ������ ������ ��� ������ ������ ��������� ������ ��� ���������, ������ ������ ��������� ��������������� ������������ ������������ ��������� ������ ������ ��������� ������ ��� ������. ������ ������������ ������������ ������������ ��������� LG ������ ��������������� ������ ������������������(orbital angular momentum)��� ��������� ������ ��� ������������ ��������������� ��������� ������ ��������� LGpl ������ ��� ��������� ��������� ��������� ��������� ������������ ������������ ������������ ��� ������ ��������� ������������ ������ ��� ��������������������� ������ ��� ������. ������ ������������ ������������ ������ ������ ������ ���������, ������ ���������, ������/��������� ������ ��� ���������, ������ ��������� ������ ������ ��� ��������� ��������� ������ ������������ ��������� ������ ������������ ������ ��������� ������ ��������������� ������, ��� ������ ������ ��������� ������ ��������� ������������ ��������� ������ ��������������� ������ ������������ ��������� ������ ������������ ������������ ������. ��������� ��������� ��������������� ��� ��������������� ������ ��������� ��������������� ��������� ������, ������������ ������������ ��� ��������� ������ ������������ ��������������� ���������. ��� ��������������� ��� ������ ������������ ��������� ��������� ��������� ������ ��������� ������������ ������������ ������������ ��������� ��������� ��������������������� ���������, ������������ TEM00, LG ������������ ��������� ��������� ��� ��������������� ��������� ������ ������ ��� ��������� ������ ������������ ������������ ������. ������ ��������� ��������� LG ������ ������ ������������ ������ ��� ��� ��� ��������� ������ ��������� ������������ ������ ������ ��������� ��� ��������� ������������������, ��������� ������������ ������������ ������������ ������������ ������������ ������ ������������ ��������� ������ ��������� ��������� ������������ ������ ��� ��������� ������������ ���������������.
��������� ��������� ������ ������������ ������, ���������, ������ ������ ������ ������ ������������ ������������ ������. ������ ��������� ��������� ��������� ��������� ������ ������������ ������ ������ ������, ������ ������, ������, ��������� ��� ��������� ������ ������������ ������������������ ������. ��������� ��������� ��������� ��������� ������ ������������ ��������� ������������ ��������� ������ ��������� ������ ��������� ������������ ��������������� ������ ��������� ������ ������������ ��������� ��������� ���������, ��������� ������������ ������ ������ ������������ ������ ������������ ������ ��������� ��������� ns ������ ��������� ��������������� ������������ ��������� ������������ ������ ��������� ��� ��������� ��������� ������ ��������� ������������ ������ ��������������� ������. ��� ������������ ��������� ��������� ������������ ��������� ��������� ������������ ������ ������-������(walk-off) ������ ��������� ������ ��������� ��������� ��������������� ��������� ������ ������������ ������ ������ ��������� ���������, ������ ��������� ������ ������ ��������� ������������ ��������� ������ ��������� ������ ������ ������������. ������������ ��������� ������������ ������������ ��������������� ������ ������ ������������ ������������ ��������� ������ ���, ������ ��� ������ ��������� ������ ������ ������ ��������������� ������ ��������� ��������� ������ ������ ��������� ��������� ������������. ��� ��������������� ��������� ������������ ��������� ��������� ������ ������ LBO��� BBO ��������� SHG ��������� ��������������� ������������������, ��������� ��������� ������ ������������ SHG��� ��������� ��������� ��������� ������ ������ ��������� ������������ ������ ��� ��� ��������� ���������������. ��������� ��������� ������������ ������-������ Yb:KGW ��������� ������ ������������ 2��� ������������ ������������������, ������ ������ ��� ������ ��������������� ������ ������ ������ ��� ������ ������ ��������� ������������ ������������ ������������ ��������� ������������ ������ ��������� ������ ��������������� ������.This thesis presents the study of beam profile tailoring and efficient frequency conversion of high power solid state lasers including the theoretical calculation and the experimental results.
Laser beams are used in a great number of application areas such as industry, medicine, defence, telecommunication, and so on. Each area requires unique beam properties, e.g. the spatial intensity distribution, laser frequency, etc., depending on its application. Especially, the spatial intensity distribution of the laser beam, which is determined by a transverse mode in an optical resonator, is one of the most important characteristics for lasers. There are two kinds of transverse laser resonator modes, a Hermite-Gaussian (HG) mode in a rectangular configuration and a Laguerre-Gaussian (LG) mode in a cylindrical configuration. Recently the LG mode laser beam attracts lots of interests for many application in areas such as optical tweezer and manipulation of particles, high capacity telecommunication, precise laser material processing, and so on.
First, this thesis reports study the characteristics of the LG mode output, including the intensity profile and the wavefront helicity. I have demonstrated generation of the LG mode optical vortex beam with well-determined handedness simply by inserting and tilting an etalon in the laser resonator and propose the selection mechanism of the wavefront helicity based on the theoretical and experimental results. Moreover this thesis proposes a simple and alternative way for controlling the transverse mode in a solid state laser employing a dual-cavity laser resonator configuration, which is invented and demonstrated for the first time in the world by this research activity. Using this approach, I have not only selected and switched a resonating mode in a simple way but also generated the laser beam with a targeted intensity profile by controlling the ratio of two resonating modes.
Second, this thesis includes the study of high-power femtosecond pulsed lasers and its frequency conversion. Femtosecond pulsed lasers systems are attractive for a lot of application areas such as industry, spectroscopy, medicine and so on. Femtosecond laser beams in the visible wavelength region can be obtained by frequency conversion of Nd-doped or Yb-doped IR laser beams using a nonlinear optical crystal. In this thesis, efficient second harmonic generation (SHG) of a Yb:KGW laser with the femtosecond pulsed output is reported. Using LBO and BBO crystals as nonlinear optical crystals, I have numerically calculated SHG conversion of the femtosecond laser beam under the various conditions. The numerical calculation is applied to a mode-locked Yb:KGW femtosecond laser constructed in house, which is in a very good agreement with experimental results.Docto
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Hydraulic hoses are one of the major mechanical components that is used as power transmission. The hydraulic hoses, which is mainly used to transmit some power through oil pressure, are difficult to design the path and analyze the stress. In the view of designing the path, Hydraulic hoses are difficult to design the centerline curve in CAD system because they have high flexibility compared to the metal, which as treated as rigid body in CAD system. This is due to the fact that setting the exact location of control points on center lines is hard task. In the view of analyzing the stress, it is almost impossible to measure the stress on hoses with strain-gauge, which is frequently used to measure the local stress of metal. Strain-gauges on hydraulic hoses are subject to be destructed due to the high value of strain on hoses compared to those of metal products. These are the main reasons why the designing the path and analyzing stress on hoses are dependent on some computer simulation method. There are two ways to simulate the Rod-like structure such as hydraulic hoses. First one is to use the software based on the Cosserat Rod Model, and the second one is to utilize the software based on the multi-body dynamics CAE. In this thesis, a comparison study is conducted between the two methods mentioned above so that presenting a useful, referable guide-line is major purpose of this thesis.Maste