• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.187-201
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• 2005

Bioprocessing technologies utilizing 'biorecognition' between a solid matrix and a protein is being widely experimented as a means to replacing the conventional, solution-based technology. Frequently the matrices are chromatographic resins with specific functional groups exposed outside. Since the reactions of and interactions with the proteins occur as they are attached to the solid matrix, this 'solid-phase' processing has distinct advantages over the solution-phase technology. Solid-phase refolding of inclusion body proteins uses ion exchange resins to adsorb denaturant-dissolved inclusion body. As the denaturant is slowly removed from the micromoiety around the protein, it is refolded into a native, three-dimensional structure. Once the refolding is complete, the folded protein can be eluted by a conventional elution technique such as the salt-gradient. This concept was successfully extended to 'EBA (expanded bed adsorption)-mediated refolding,' in which the denaturant-dissolved inclusion body in whole cell homogenate is adsorbed to a Streamline resin while cell debris and other impurity proteins are removed by the EBA action. The adsorbed protein follows the same refolding steps. This solid-phase refolding process shows the potential to improve the refolding yield, reduce the number of processing steps and the processing volume and time, and thus improve the overall process economics significantly. In this paper, the experimental results of the solid-phase refolding technology applied to several biopharmaceutical proteins of various types are presented.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.607-613
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• 2016

The pleura is known as an end target organ of exposure to toxic environmental materials such as fine particulate matter and asbestos. Moreover, long-term exposure to hazardous materials can eventually lead to fatal lung disease such as diffuse pleural fibrosis or mesothelioma. Chest computed tomography (CT) and ultrasound are gold standard imaging modalities for detection of advanced pleural disease. However, a diagnostic tool for early detection of pleural reaction has not been developed yet due to difficulties in imaging ultra-fine structure of the pleura. Optical coherence tomography (OCT), which provides cross-sectional images of micro tissue structures at a resolution of 2-10 μm, can image the mesothelium with a thickness of ~100 μm and therefore enables investigation of the early pleural reaction. In this study, we induced the early pleural reaction according to a time sequence after pleurodesis using talc, which has been widely used in the clinical field. The pleural reaction in talc grouped according to the time sequence (1st, 2nd, 4th weeks) showed a significant thickening (average thickness: 45 ± 7.5 μm, 80 ± 10.7 μm, 90 ± 12.5 μm), while the pleural reaction in sham and normal groups showed pleural change from normal to minimal thickening (average thickness: 16 ± 5.5 μm, 17 ± 4.5 μm, 15 ± 6.5 μm, and 12 ± 7.5 μm, 13 ± 2.5 μm, 12 ± 3.5 μm). The measurement of pleural reaction by pathologic examinations was well-matched with the measurement by OCT images. This is the first study for measuring the thickness of pleural reactions using a biophotonic modality such as OCT. Our results showed that OCT can be useful for evaluating the early pleural reaction.

• Journal of The Korean Astronomical Society
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• v.36 no.3
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• pp.89-95
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• 2003

Observations of dark matter dominated dwarf and low surface brightness disk galaxies favor density profiles with a flat-density core, while cold dark matter (CDM) N-body simulations form halos with central cusps, instead. This apparent discrepancy has motivated a re-examination of the microscopic nature of the dark matter in order to explain the observed halo profiles, including the suggestion that CDM has a non-gravitational self-interaction. We study the formation and evolution of self-interacting dark matter (SIDM) halos. We find analytical, fully cosmological similarity solutions for their dynamics, which take proper account of the collisional interaction of SIDM particles, based on a fluid approximation derived from the Boltzmann equation. The SIDM particles scatter each other elastically, which results in an effective thermal conductivity that heats the halo core and flattens its density profile. These similarity solutions are relevant to galactic and cluster halo formation in the CDM model. We assume that the local density maximum which serves as the progenitor of the halo has an initial mass profile ${\delta}M / M {\propto} M^{-{\epsilon}$, as in the familiar secondary infall model. If $\epsilon$ = 1/6, SIDM halos will evolve self-similarly, with a cold, supersonic infall which is terminated by a strong accretion shock. Different solutions arise for different values of the dimensionless collisionality parameter, $Q {\equiv}{\sigma}p_br_s$, where $\sigma$ is the SIDM particle scattering cross section per unit mass, $p_b$ is the cosmic mean density, and $r_s$ is the shock radius. For all these solutions, a flat-density, isothermal core is present which grows in size as a fixed fraction of $r_s$. We find two different regimes for these solutions: 1) for $Q < Q_{th}({\simeq} 7.35{\times} 10^{-4}$), the core density decreases and core size increases as Q increases; 2) for $Q > Q_{th}$, the core density increases and core size decreases as Q increases. Our similarity solutions are in good agreement with previous results of N-body simulation of SIDM halos, which correspond to the low-Q regime, for which SIDM halo profiles match the observed galactic rotation curves if $Q {\~} [8.4 {\times}10^{-4} - 4.9 {\times} 10^{-2}]Q_{th}$, or ${\sigma}{\~} [0.56 - 5.6] cm^2g{-1}$. These similarity solutions also show that, as $Q {\to}{\infty}$, the central density acquires a singular profile, in agreement with some earlier simulation results which approximated the effects of SIDM collisionality by considering an ordinary fluid without conductivity, i.e. the limit of mean free path ${\lambda}_{mfp}{\to} 0$. The intermediate regime where $Q {\~} [18.6 - 231]Q_{th}$ or ${\sigma}{\~} [1.2{\times}10^4 - 2.7{\times}10^4] cm^2g{-1}$, for which we find flat-density cores comparable to those of the low-Q solutions preferred to make SIDM halos match halo observations, has not previously been identified. Further study of this regime is warranted.

• Polymer(Korea)
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• v.38 no.6
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• pp.752-759
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• 2014

Crosslinked polyimides (PIs) were synthesized by reacting 4,4'-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA) and 2,2'-bis(trifluoromethyl)benzidine (TFDB) with various ratios of the cross-linkable, end-capping agent cis-1,2,3,6-tetrahydrophthalic anhydride (CDBA) via ring-opening metathesis polymerization. Residual stress behaviors were investigated in-situ during thermal imidization of the crosslinked PI precursors using a thin film stress analyzer (TFSA) by wafer bending method. The thermal properties were investigated via differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and thermogravimetric analysis (TGA). The optical properties were measured by ultraviolet-visible spectrophotometer (UV-vis) and spectrophotometry. All properties were interpreted with respect to their morphology of crosslinked networks. With increasing the amounts of the end-capping agent, the residual stress decreased from 27.9 to -1.3 MPa, exhibited ultra-low stress and high thermal properties. The minimized residual stress and enhanced thermal properties of the crosslinked PI makes them potential candidates for versatile high-density multi-layer structure applications.

• Korean Journal of Materials Research
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• v.13 no.8
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• pp.497-502
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• 2003

Crystallographic characteristics and interfacial structures of $Al_2$$O_3$and $ZrO_2$dielectric films prepared by atomic layer chemical vapor deposition (ALCVD) were investigated at atomic scale by high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS)/electron energy-loss spectroscopy (EELS) coupled with a field-emission transmission electron microscope. The results obtained from cross-sectional and plan-view specimens showed that the $Al_2$$O_3$film was crystallized by annealing at a high temperature and its crystal system might be evaluated as either cubic or tetragonal phase. Whereas the $ZrO_2$film crystallized during deposition at a low temperature of ∼$300^{\circ}C$ was composed of both tetragonal and monoclinic phase. The interfacial thickness in both films was increased with the increased annealing temperature. Further, the interfacial structures of X$ZrO_2$$O_3$and $ZrO_2$films were discussed through analyses of EDS elemental maps and EELS spectra obtained from the annealed films, respectively.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.1
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• pp.9-14
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• 2004

Rational sense is affected by emotion. If we add the factor of estimated emotion by environment information into robots, we may get more intelligent and human-friendly robots. However, various sensory information and pattern classification are prescribed for robots to learn emotion so that the networks are suitable for the necessity of robots. Neural network has superior ability to extract character of system but neural network has defect of temporal cross talk and local minimum convergence. To solve the defects, many kinds of modular neural networks have been proposed because they divide a complex problem into simple several subproblems. The modular neural network, introduced by Jacobs and Jordan, shows an excellent ability of recomposition and recombination of complex work. On the other hand, the recurrent network acquires state representations and representations of state make the recurrent neural network suitable for diverse applications such as nonlinear prediction and modeling. In this paper, we applied recurrent network for the expert network in the modular neural network structure to learn data pattern based on emotional assessment. To show the performance of the proposed network, simulation of learning the environment and behavior pattern is proceeded with the real time implementation. The given problem is very complex and has too many cases to learn. The result will show the performance and good ability of the proposed network and will be compared with the result of other method, general modular neural network.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.428-436
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• 2012

This study aimed to develop the multi-span plastic greenhouse which is suitable for tomato cultivation and is safe against climatic disasters such as typhoon or heavy snow. The width and heights of eaves and ridge of newly developed tomato greenhouse are 7, 4.5 and 6.5 m, respectively. The width is the same but the eaves and ridge heights are 1.8 and 2 m higher than conventional 1-2 W greenhouses, respectively. Cross beam has been designed as a truss structure so it can sustain loads of tomato and equipment. Tomato greenhouse has been designed according to climatic disaster preventing design standard maintaining the high height. In other words, the material dimensions and interval of materials including column and rafter have been set to stand against $40m{\cdot}s^{-1}$ of wind and 40 cm of snow. Tomato greenhouse has been equipped with rack-pinion type roof vents which have been used in glass greenhouse in order to prevent excessive rise in air temperature. This vent type is different from that of 1-2 W type greenhouse which is made by rolling up and down the vinyl at upper part of column. Roof vents are installed at ridge, and thus external air inflow and natural ventilation are maximized. As the height increases, heating cost increase as well and, therefore, tomato greenhouse has been equipped with multi-layered thermal curtain, of which thermo-keeping is excellent, to prevent heat from escaping.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.2
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• pp.37-43
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• 1999

Modules of the system that requires large capacity and high-speed information processing are implemented in the form of MCM that allows high-speed data processing, high density circuit integration and widely applied to such fields as ATM, GPS and PCS. Hence we developed the ATM switching module that is consisted of three chips and 2.48 Gbps data throughput, in the form of 10 multi-layer by Cu/Photo-BCB and 491pin PBGA which size is $48 \times 48 \textrm {mm}^2$. hnologies required for the development of the MCM includes extracting parameters for designing the substrate/package through the interconnect characterization to implement the high-speed characteristics, thermal management at the high-density MCM, and the generation of the testability that is one of the most difficult issues for developing the MCM. For the development of the ATM Switching MCM, we extracted signaling delay, via characteristics and crosstalk parameters through the interconnect characterization on the MCM-D. For the thermal management of 15.6 Watt under the high-density structure, we carried out the thermal analysis. formed 1.108 thermal vias through the substrate, and performed heat-proofing processing for the entire package so that it can keep the temperature less than $85^{\circ}C$. Lastly, in order to ensure the testability, we verified the substrate through fine pitch probing and applied the Boundary Scan Test (BST) for verifying the complex packaging/assembling processes, through which we developed an efficient and cost-effective product.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.63-67
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• 2016

In this paper, we present an indirect method of elastic modulus measurement for various lamination layers formed on polymer-based compliant substrates. Although the elastic modulus of every component is crucial for mechanically reliable microelectronic devices, it is difficult to accurately measure the film properties because the lamination layers are hardly detached from the substrate. In order to resolve the problem, 3-point bending test is conducted with a film-substrate specimen and area transformation rule is applied to the cross-sectional area of the film region. With known substrate modulus, a modulus ratio between the film and the substrate is calculated using bending stiffness of the multilayered specimen obtained from the 3-point bending test. This method is verified using electroplated copper specimens with two types of film-substrate structure; double-sided film and single sided film. Also, common dielectric layers, prepreg (PPG) and dry film solder resist (DF SR), are measured with the double-sided specimen type. The results of copper (110.3 GPa), PPG (22.3 GPa), DF SR (5.0 GPa) were measured with high precision.

• Journal of the Korean Society of Earth Science Education
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• v.9 no.2
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• pp.163-172
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• 2016

The aim of this study is to investigate the geological features distributed in the northwest coast, Goheung Gun as a geological field course of all levels. The study area is about 1.6km coast in direction of northwest from Sumundong ferry to Jangsun beach. The learning contents of the geology units in science textbooks from elementary school to high school was analyzed and, geomorphology and geology of study area was investigated for this study. In this study area, lots of geomorphology and geology elements related to the learning contents of the geology units in science textbooks were founded such as gravel beach, sea cliff, granite, rhyolite, andesite, gneiss, sedimentary rocks, fault, unconformity, stratification, cross bedding, graded bedding, intrusion structure, vein, dyke, plant fossil and spheroidal weathering. Characteristically, strata, stratification, granite, sedimentary rocks(conglomerate, sandstone, mudstone and shale), fault, plant fossil and weathering phenomenon were commonly involved with the learning contents of the geology units in elementary school science, middle school science and high school earth science I, II. This area is to be recommended as a site of geological field course for all students from elementary school to high school, as various field work materials for geological learning were distributed and, geological observation trail of about 400m in length for observation of strata and so on was installed along the coast in direction of the northwest from Sumundong ferry.