• 한국수정란이식학회지
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• 제14권1호
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• pp.23-29
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• 1999

The objectives of the study were to establish sperm separation method and duration of insemination for bovine IVF. Oocytes from slaughterhouse ovaries were matured and fertilized using general protocol. After 18 or 42 h of insemination, six to ten embryos were placed into a 30${mu}ell$ drop of each medium, and the embryos were examined 7~10d post in semination without medium renewal. First, we compared Percoll gradient will swim-up technique for sperm separation. There was no difference in cleavage rates between them, but the development rates over morula stage of oocytes fertilized with sperm separated by Percoll gradient was significantly higher than that sperm selected by swim-up technique (p<0.05). Second, we evaluated development of bovine embryos derived from the IVF procedure with different durations(18 vs 42 h) of fertilization. There was also no difference in cleavage rates, but the development to blastocyst stage of oocytes exposed in cleavage rates, but the development to blastocyst stage of oocytes exposed to sperm for 42 h was significantly higher than that exposed for 18 h (p<0.05). In conclusion, Percoll gradient can be used for sperm selecton, improving of embryonic development. Also, 42h of IVF may improve the development of bovine embryos.

• 말소리와 음성과학
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• 제7권4호
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• pp.17-25
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• 2015

For blind source separation of convolutive mixtures, FDICA(Frequency Domain Independent Component Analysis) algorithms are generally used. Since FDICA algorithm such as Sawada FDICA, IVA(Independent Vector Analysis) works on the frequency bin basis with a natural gradient descent method, it takes much time to converge. In this paper, we propose a new method to improve convergence speed in FDICA algorithm. The proposed method reduces the number of iteration drastically in the process of natural gradient descent method by applying a weighted inner product constraint of unmixing matrix. Experimental results have shown that the proposed method achieved large improvement of convergence speed without degrading the separation performance of the baseline algorithms.

• 대한기계학회논문집B
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• 제32권11호
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• pp.856-862
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• 2008

This paper presents the characterization of a continuous magnetophoretic microseparator for separating white and red blood cells from peripheral whole blood cells based on their native magnetic properties. The magnetophoretic microseparator separated the blood cells using a high gradient magnetic separation (HGMS) method without the use of additives such as magnetic beads or probing materials. Experimental results show that the paramagnetic capture mode microseparator can continuously separate out 93.5% of red blood cells and 97.4% of white blood cells from diluted whole blood, and the diamagnetic capture mode microseparator can continuously separate out 89.7% of red blood cells and 72.7 % of white blood cells by using applying an external magnetic flux of 0.2 T using a permanent magnet.

• KSBB Journal
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• 제16권6호
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• pp.533-537
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• 2001

유청 단백질 중에서 $\alpha$-lactalbumin, $\beta$-lactoglobulin를 고성능 막 크로마코그래피를 이용하여 분리하는 것이다. 분리 메카니즘은 음이온 교환작용이며 고정상은 CIM DEAE, QA, So$_3$ disk (16$\times$3 mm)을 사용하였다. 이동상은 buffer A (20 mM Tris-HCI, pH 7.3)와 buffer B (buffer A + 1 M NaCl)를 사용하였으며 $\alpha$-lactalbumin, $\beta$-lactoglobulin를 분리하기 위해서 구배용매 조성법을 사용하였다. 각 이동상의 조성에 따른 최적의 이동상 조성(Buffer A/Buffer B=100/0 - 30/70 vol%, gradient time 1 min, 30/70 - 10/90 vol%, gradient time 2 min)을 실험적으로 얻었고 4 ml/min의 이동상 유속에서 3분내에 $\alpha$-lactalbumin, $\beta$-lactoglobulin를 분리 할 수 있었다. 유청 단백질 중에 $\alpha$-lactalbumin, $\beta$-lactoglobulin을 HPMC을 적용하여 분리하였고, 유청 단백질의 기능적 성질, 분리 방법에 대해 알아보았다.

• 한국초전도ㆍ저온공학회논문지
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• 제18권1호
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• pp.28-32
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• 2016

There are a few thousand abandoned metal mines in South Korea. The abandoned mines cause several environmental problems including releasing acid mine drainage (AMD), which contain a very high acidity and heavy metal ions such as Fe, Cu, Cd, Pb, and As. Iron oxides can be formed from the AMD by increasing the solution pH and inducing precipitation. Current study focused on the formation of iron oxide in an AMD and used the oxide for adsorption of heavy metals. The heavy metal adsorbed iron oxide was separated with a superconducting magnet. The duration of iron oxide formation affected on the type of mineral and the degree of magnetization. The removal rate of heavy metal by the adsorption process with the formed iron oxide was highly dependent on the type of iron oxide and the solution pH. A high gradient magnetic separation (HGMS) system successfully separated the iron oxide and harmful heavy metals.

• ETRI Journal
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• 제35권2호
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• pp.193-199
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• 2013

This paper addresses nonnegative independent component analysis (NICA), with the aim to realize the blind separation of nonnegative well-grounded independent source signals, which arises in many practical applications but is hardly ever explored. Recently, Bertrand and Moonen presented a multiplicative NICA (M-NICA) algorithm using multiplicative update and subspace projection. Based on the principle of the mutual correlation minimization, we propose another novel cost function to evaluate the diagonalization level of the correlation matrix, and apply the multiplicative exponentiated gradient (EG) descent update to it to maintain nonnegativity. An efficient approach referred to as the EG-NICA algorithm is derived and its validity is confirmed by numerous simulations conducted on different types of source signals. Results show that the separation performance of the proposed EG-NICA algorithm is superior to that of the previous M-NICA algorithm, with a better unmixing accuracy. In addition, its convergence speed is adjustable by an appropriate user-defined learning rate.

• Journal of Magnetics
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• 제22권2호
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• pp.214-219
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• 2017

Magnetic separators that clean the fluid stream from impurities, protect the installations in numerous industries. This paper introduces a graphical user interface (GUI) which proposes an optimized coil separating magnetic particles with a radius from 1 up to 500 µm. High gradient magnetic fields are employed in an arbitrary user defined fluidic channel which is made of a nonmetallic material. The effects of coil parameters are studied and adjusted to design an optimum coil with a minimum Ohmic loss. In addition, to design the coil scheme based on the particle movements, a mathematical particle-tracing model within the fluid channels has been utilized. In comparison to conventional magnetic separators, this model is reconfigurable by the user, produces a weaker magnetic field, allows for continuous purifying and is easy to install, with high separation efficiency. The presented GUI is simple to use, where the coil's manufacturing limitations can be specified.

• 한국초전도ㆍ저온공학회논문지
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• 제20권2호
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• pp.6-10
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• 2018

Removal of iron oxide scale from feed-water in thermal power plant can improve power generation efficiency. We have proposed a novel scale removal system utilizing High Gradient Magnetic Separation (HGMS). This system can be applied to high temperature and pressure area. We have conducted the lab-scale model experiments using ${\varphi}50mm$ filters and it demonstrated high removal efficiency in HGMS, but scale-up of the system is required toward practical use. In this study, we conducted a large scale mock-up HGMS experiment. We used the superconducting solenoidal magnet with ${\varphi}400mm$ bore and demonstrated that our HGMS system can achieve sufficient scale removal capacity that is required to introduce into both off-line and on-line system.

• 한국초전도ㆍ저온공학회논문지
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• 제11권4호
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• pp.8-11
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• 2009

This study introduced wastewater treatment method by High Gradient Magnetic Separation (HGMS). HGMS treatment was high efficient method for various industrial wastewaters. The system is currently research state, but we have surveyed commercialize the technology for industry. In rolling plate process, coolant wastewater was recycled by sedimentation and sand filter system. It needs several large reservoirs and long time to remove suspended solid (SS) like metal fines and iron oxide in hot rolling plate making process. If removing rate of suspended solid in rolling coolant wastewater is improved by using HGMS system, the productivity of working process can be increased and the area of reservoir can be reduced. We manufactured high temperature superconducting HGMS system that had a purpose to treatment of coolant wastewater in rolling plate process. We fabricated the prototypes of magnetic matrix filter consisting of stainless steel 430 mesh, which is a core component in the magnetic separation system, In our basic preliminary experiment using HGMS system, it has been clear that the fine paramagnetic particles in the coolant wastewater obtained from rolling plate process of POSCO can be separated with high efficiency.

• 대한기계학회논문집B
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• 제24권6호
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• pp.886-893
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• 2000

The Characteristics of dividing the dispersed bubble, plug, and slug steam-water flow in the horizontal junctions with horizontal branches have been experimentally investigated. The experimental investigation of the separation phenomena in a $45^{\circ}$ horizontal wye with equal pipe inner diameter of 25 mm is presented to provide a data base for the development and verification of the analytical models. The phase separation and pressure distribution in the three legs of each test section are obtained through the set of measurements made in the present work. And the dependence of phase separation on different parameters, such as inlet quality and mass flux, is discussed.