• Journal of Magnetics
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• v.17 no.4
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• pp.302-307
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• 2012

We have designed, fabricated and tested an integrated microfluidic chip with a Planar Hall Effect (PHE) sensor. The sensor was constructed by sequentially sputtering Ta/NiFe/Cu/NiFe/IrMn/Ta onto glass. The microfluidic channel was fabricated with poly(dimethylsiloxane) (PDMS) using soft lithography. Magnetic nanoparticles suspended in hexadecane were used as ferrofluid, of which the saturation magnetisation was 3.4 emu/cc. Droplets of ferrofluid were generated in a T-junction of a microfluidic channel after hydrophilic modification of the PDMS. The size and interval of the droplets were regulated by pressure on the ferrofluid channel inlet. The PHE sensor detected the flowing droplets of ferrofluid, as expected from simulation results. The shape of the signal was dependent on both the distance of the magnetic droplet from the sensor and the droplet length. The sensor was able to detect a magnetic moment of $2{\times}10^{-10}$ emu at a distance of 10 ${\mu}m$. This study provides an enhanced understanding of the magnetic parameters of ferrofluid in a microfluidic channel using a PHE sensor and will be used for a sample inlet module inside of integrated magnetic lab-on-a-chip systems for the analysis of biomolecules.

• KSBB Journal
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• v.24 no.1
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• pp.101-105
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• 2009

Alcohol oxidation activities and optimization of extraction conditions of Rrhus verniciflua Stokes (RVS) extract were evaluated for the development of a functional biomaterial for improving liver function. When alcohol oxidation activities of RVS was analyzed, the Rrhus verniciflua Stokes bark (RVSB) were higher than the Rrhus verniciflua Stokes heartwood (RVSH). Alcohol oxidation activity value of RVSB increased in a concentration-dependent manner. In the comparative analysis between Hovenia dulcis Thunb (HOT) and Alnus japonica Steud (AJS) which was reported as a alcohol oxidation material, alcohol oxidation activity is much higher than the others. The experimental conditions were optimized for alcohol oxidation-active components production from RVSB. The extraction conditions such as temperature, time, pH and particle size were performed. It was recommended to extract the alcohol oxidation-active components from RVSB by hot water (pH 7.0) at $85^{\circ}C$ for 8 hours.

• Journal of the Economic Geographical Society of Korea
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• v.16 no.2
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• pp.149-166
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• 2013

The purpose of this study is to analyze the regional disparity and its determinants of $CO_2$ emission from the residential energy consumption in China. This study examines factors that affect the $CO_2$ emission per capita using the panel model. The panel model was set by a balanced panel data for 30 provinces and for the period of 2006~2011. $CO_2$ emission per capita is used as the dependent variable and characteristics of the household and regional physical environmental factors are selected as the explanatory variables. The important findings can be summarized as follows. $CO_2$ emission per capita is influenced by the ratio of the graduate students, household size, the ratio of the old-aged, female economic participation rate. High residential density is negatively affected on $CO_2$ emission. The findings suggest that the effect of policies reducing $CO_2$ emission per capita may vary by characteristics of the household, energy sources and regional climate. The results of this empirical study give some implications to reduce the residential energy consumption in the era of climate change.

• Journal of the Korean Society of Costume
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• v.64 no.5
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• pp.30-49
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• 2014

Mobile shopping, through the use of the smart phone, has become a very popular shopping method for consumers due to it not being limited by time or place. This research aims do the following:1)find the causes for consumers shifting to mobile shopping with the focus on fashion and beauty items; and in order to so, this research will use the TAM that was found by David et al (1989), and 2) distinguish any behavioral differences between consumer groups divided into purchasing intention of fashion and beauty items through smart phone. Path analysis was performed to verify the cause-and-effect relationship between the variables. Personal characteristics(i.e. market maven, time orientation), perceived usability, ease of use, attitude towards mobile shopping, and purchase intentions were all treated as dependant variables. The results showed that attitude towards mobile shopping was the most important variable on mobile shopping intentions. Time-oriented and Market Maven were thought to affect mobile shopping attitude and the dependent variables of purchase intention. Also, when purchasing smart phones, consumers highly valued smart phone's popularity; people with higher purchasing intention mainly used entertainment and utility apps. The following are the main reasons for not purchasing through mobile shopping: they are slower than computers, inconveniences in viewing due to small size of the screen, and security issues. The consumers used the internet as their main source of acquiring daily information. In this research, factors that affect the purchase intention were studied. However, it is difficult to firmly insist that this research correctly predicts the actual purchase intention-further studies need to be done to investigate the relationship between mobile purchase intention and actual purchase intention.

• ALGAE
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• v.30 no.1
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• pp.35-47
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• 2015

The marine sand-dwelling dinoflagellate Polykrikos lebourae possesses obvious gold-brown pigmented plastids as well as taeniocyst-nematocyst complex structures. Despite of the presence of the visible plastids, previous attempts to establish this species in culture all failed and thus the unavailability of cultures of this species has posed a major obstacle to further detailed exploration of ecophysiology of the dinoflagellate. Here, we isolated P. lebourae from sandy sediment of an intertidal flat on Korean western coast, successfully established it in culture, and have been maintaining the stock culture over the past 3 years. Using this stock culture, we explored phagotrophy and potential prey resources of P. lebourae, growth and grazing responses of P. lebourae to different prey organisms, the effect of prey concentration on growth and grazing rates and gross growth efficiency (GGE) of P. lebourae when fed three different prey organisms, and the growth kinetics of P. lebourae under different light regimes. P. lebourae captured prey cells using a tow filament and then phagocytized them through the posterior end. The dinoflagellate was capable of ingesting a broad range of prey species varying in size, but not all prey species tested in this study supported its sustained growth. GGE of P. lebourae was extremely high at low prey concentration and moderate or low at high prey concentrations, indicating that P. lebourae grows heterotrophically at high prey concentrations but its growth seems to be more dependent on a certain growth factor or photosynthesis of plastids derived from the prey. In the presence of prey in excess, P. lebourae grew well at moderate light intensity of $40{\mu}mol$ photons $m^{-2}s^{-1}$, but did not grow at dim and high (10 or $120{\mu}mol$ photons $m^{-2}s^{-1}$) light intensities. Our results suggest that the benthic dinoflagellate P. lebourae is an obligate mixotroph, requiring both prey and light for sustained growth and survival.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.5
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• pp.423-430
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• 2014

Noise and vibration, which occur in a pipe, are usually caused by the interaction between the turbulent flow and nearby wall. Although it can be estimated by a simple case of expanded pipes having complex turbulent flow, the radiated noise is highly dependent upon the size, shape, and thickness of the given model. In addition, the radiated noise propagates and has serious interference and destabilization effects on the surrounding systems, which can lead to fatigue fracture and failure. This study took advantage of the variety of commercial programs, such as FLUENT (flow solver), NASTRAN (dynamic motion solver of complex structures) and VIRTUAL LAB (radiated noise solver) based on the boundary element method (BEM), to understand the underlying physics of flow noise. The expanded pipe has separation and a high pressure drop because of the abrupt change in the cross-section. Based on the radiated noise calculations, the noise level was reduced to around 20 dB in the range of 100-500 Hz.

• Management & Information Systems Review
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• v.31 no.2
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• pp.61-87
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• 2012

In order to improve the value of individuals and the organization's performance, strenuous efforts have been made on improving their human capital and expanding their social capital by members of the organization. Accordingly, the purpose of this study is to verify how members' intimacy network of an organization affects the organization's performance. In this research, they are verified by setting the characteristic of individuals intimacy network as an independent variable, and the job performance and the degrees of cooperation in the network as dependent variables. The results of this study show as follows. First, the size, strength, approach of intimacy network showed significant results. In particular, the first impression when first saw him becomes an important variable. And, that is affected by the approach of intimacy network. Second, the approach of intimacy network has a high impact on the cooperative behavior and job performance in a group which is formed by relationships through face-to-face contract.

• Health Policy and Management
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• v.24 no.1
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• pp.35-46
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• 2014

Background: This paper describes the relationship and effect of health examination on personal medical cost by identifying the difference of the cost for medical care in physician visit between the population without and with health examination. Methods: After classifying into three cohorts in which, independent variables were designed according to the Andersen's behavioral model, the association of personal medical cost for medical care and prescription drugs which is dependent variable was analyzed by t-test and Mann-Whitney test for description and gamma regression model for inference. Results: In personal average medical cost, the population with health examination paid significantly more than without health examination, 11.6% more in cohort 2008, 26.6% more in cohort 2009, and 48.0% more in combined cohort. The odds ratio on medical expenditure of outpatients with health examination was 1.067, 1.126, 1.398 significantly in cohort 2008, 2009, and combined cohort respectively, comparing to the group without health examination. In independent variables, that is female, the elderly, never married, non-working, non-metropolitan, the higher family income, the smaller family size, people with disability, the people with chronic disease, and people with health examination have significantly being paid more tendency showing positive association with medical cost. Conclusion: This result showed that medical expenditure in physician visit has been increased after taking a health examination. Therefore reasonable limitation of getting preventive medical service is suggested to avoid medical shopping around and reduce being repeated health examination by unifying control to find out easily the clinical results from various medical facilities.

• Korean Journal of Veterinary Research
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• v.34 no.4
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• pp.769-779
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• 1994

The root of Bupleurum falcatum L.(BF) has been widely used in oriental medicine as a major camponent in many prescriptions for chronic hepatitis, renal disease, tuberculosis and some other infectious diseases. Many attempts have done to investigate the therapeutic effects of these principles. However, any kinds of screenig on immune regulatory- and antitumor- effects of BF has not been reported. The present study, therefore, was undertaken to investigate the BF-effects on cellular- and humoral-immune responses, phagocytic activities of macrophages, lymphokine- and Immunoglobulin(Ig)-production of lymphocytes, tumorigenesis of implanted sarcoma 180 cells and B16 melanoma cells, and proliferations of some tumor cell lines(Fsa II, 3LL and EL4). BF increased phagocytic activities of mouse peritoneal macrophages in a dose- and time-dependent fashion. Arthus reaction and antibody responses to SRBC were slightly enhanced but delayed hypersensitivity was depresed when BF was injected before- and after-SRBC sensitization. BF inhibited the proliferative responses of human tonsillar lymphocytes to PHA- and Con A-stimulation but slightly augmented the response of these cells to Staphylococcus aureus Cowan 1(SAC)-activation. Ig secretion of human mononuclear cells activated with SAC was slightly increased by BF. BF significantly augmented the SAC-induced IL 6 production of human mononuclear cells but not influenced Con Ainduced IL 2 secretion. NK cell activities of mouse splenocytes were somewhat increased when BF was pretreated and this responses were due to the increment of binding affinities of effector cells to target cells and of lytic activities of effector cells against target cells. In vitro BF significantly inhibited the proliferations of cancer cells such as Fsa II, 3LL and EL4 strains. BF decreased not only the frequency of tumor induction but also the tumor size per sarcoma 180 or B16 cell-implanted mouse. Taken together, these results indicate that BF is one of the potential immunomodulator, and suggest its possibility to be used as a desirable antitumor agent.

• Progress in Superconductivity and Cryogenics
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• v.15 no.2
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• pp.20-23
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• 2013

For sensitive measurements of micro-Tesla nuclear magnetic resonance (${\mu}T$-NMR) signal, a low-noise superconducting quantum interference device (SQUID) system is needed. We have fabricated a liquid He dewar for an SQUID having a large diameter for the pickup coil. The initial test of the SQUID system showed much higher low-frequency magnetic noise caused by the thermal magnetic noise of the aluminum plates used for the vapor-cooled thermal shield material. The frequency dependence of the noise spectrum showed that the noise increases with the decrease of frequency. This behavior could be explained from a two-layer model; one generating the thermal noise and the other one shielding the thermal noise by eddy-current shielding. And the eddy-current shielding effect is strongly dependent on the frequency through the skin-depth. To minimize the loop size for the fluctuating thermal noise current, we changed the thermal shield material into insulated thin Cu mesh. The magnetic noise of the SQUID system became flat down to 0.1 Hz with a white noise of 0.3 $fT/{\surd}Hz$, including the other noise contributions such as SQUID electronics and magnetically shielded room, etc, which is acceptable for low-noise ${\mu}T$-NMR experiments.