• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.1
• /
• pp.83-88
• /
• 2017

This paper related with the performance evaluation of H-MMA (Hybrid-MMA) which is applying the adaptive modulus and adaptive step size concept to MMA adaptive equalization algorithm in order to reduce the intersymbol interference that is occurred in communication channel for digital code transmission. In the conventional MMA adaptive equalizer, the coefficient is updated by using the equalizer output and possible to compensation of amplitude and phase in 2nd dimensional QAM signal, the equalization performance were degraded due to fixed modulus and step size. For the overcomming the abovemensioned problem, it is possible to improving the equalization performance in the 2nd dimensional QAM signal by applying the adaptive modulus and adaptive step size propotional to equalizer output signal to the conventional MMA algorithm. The computer simulation was performed in the same channel for the compare the performance of MMA and proposed H-MMA which is proposed in this paper. As a result of simulation, the proposed H-MMA has slower convergence time in order to arriving the steady state than MMA. But after the steady state, H-MMA has more superior to the MMA in every performance index and the equalization noise was reduced.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.25 no.4 s.34
• /
• pp.123-131
• /
• 1999

Liquid crystal known as a rheological barrier to coalescence of oil droplets, increases emulsion stability, water-holding capacity and promotes active material penetration to skin. Some investigation for its rheological characteristics have been reported but its relations to consumer perception have been rarely published. In this study, oil/water emulsion and oil/liquid crystal/water systems were manufactured using the same composition or Behenyltrimethylammonium chloride/Cetostearyl alcohol/Lanolin oil. and rheological properties or each system were investigated with Cone and Plate rheometer. The formation of liquid crystalline phase was observed with polarized microscope and Differential Scanning Calorimeter. Continuous shear experiment, creep, yield and water holding capacity were measured for oil/water and oil/liquid crystal/water systems. The results were compared with sensory evaluations. Oil/liquid crystal/water system showed higher,viscosity at the same shear rate. higher viscoelasticity and higher yield stress than oil/water system. These properties were expected to show good spreadability and excellent richness without waxiness in hair can: products of creme type. This expectation was consistent with the results of sensory experiments. Water-holding capacity was evaluated by measuring residual water of specimens at specific temperature and relative humidity. Oil/liquid crystal/water system was proved to have higher ability to hold water in comparison with oil/water system. The results indicated that oil/liquid crystal/water system was of benefit to rheological properties creme type hair care products.

• Nuclear Engineering and Technology
• /
• v.38 no.2
• /
• pp.147-154
• /
• 2006

Thermal fatigue of the coolant circuits of PWR plants is a major issue for nuclear safety. The problem is especially accute in mixing zones, like T-junctions, where large differences in water temperature between the two inlets and high levels of turbulence can lead to large temperature fluctuations at the wall. Until recently, studies on the matter had been tackled at EDF using steady methods: the fluid flow was solved with a CFD code using an averaged turbulence model, which led to the knowledge of the mean temperature and temperature variance at each point of the wall. But, being based on averaged quantities, this method could not reproduce the unsteady and 3D effects of the problem, like phase lag in temperature oscillations between two points, which can generate important stresses. Benefiting from advances in computer power and turbulence modelling, a new methodology is now applied, that allows to take these effects into account. The CFD tool Code_Saturne, developped at EDF, is used to solve the fluid flow using an unsteady L.E.S. approach. It is coupled with the thermal code Syrthes, which propagates the temperature fluctuations into the wall thickness. The instantaneous temperature field inside the wall can then be extracted and used for structure mechanics computations (mainly with EDF thermomechanics tool Code_Aster). The purpose of this paper is to present the application of this methodology to the simulation of a straight T-junction mock-up, similar to the Residual Heat Remover (RHR) junction found in N4 type PWR nuclear plants, and designed to study thermal striping and cracks propagation. The results are generally in good agreement with the measurements; yet, in certain areas of the flow, progress is still needed in L.E.S. modelling and in the treatment of instantaneous heat transfer at the wall.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.4
• /
• pp.83-93
• /
• 2003

This research, in order to study the effects of initial shear stress of anisotropically consolidated sand that has 0.558% fines, performed several undrained static and dynamic triaxial test. To simulate the real field conditions, loose and dense samples were prepared. Besides, the cyclic shear strength of Nakdong River sand under various combinations of initial static shear stress, stress path, pore water pressure and residual strength relationship was studied. By using Bolton's theory, peak internal friction angle at failure which has considerable effects on the relative density and mean effective stress was determined. In p'- q diagram, the phase transformation line moves closer to the failure line as the specimen's initial anistropical consolidation stress increases. Loose sands were more affected than dense sands. The increase of consolidation stress ratio from 1.4 to 1.8 had an effect on liquefaction resistance strength resulting from the increase of relativity density, and showed similar CSR values in dense specimen condition.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.2004-2006
• /
• 1996

A thermally driven polysilicon micro actuator has been fabricated using surface micromachining techniques. It consists of P-doped polysilicon as a structural layer and TEOS (tetracthylorthosilicate) as a sacrificial layer. The polysilicon was annealed for the relaxation of residual stress which is the main cause to its deformation such as bending and buckling. And the newly developed HF VPE (vapor phase etching) process was also used as an effective release method for the elimination of sacrificial TEOS layer. The thickneas of polysilicon is $2{\mu}m$ and the lengths of active and passive polysilicon cantilevers are $500{\mu}m$ and $260{\mu}m$, respectively. The actuation is incurred by die thermal expansion due to the current flow in the active polysilicon cantilever, which motion is amplified by lever mechanism. The moving distance of polysilicon micro actuator was experimentally conformed as large as $21{\mu}m$ at the input voltage level of 10V and 50Hz square wave. The actuating characteristics are investigated by simulating the phenomena of heat transfer and thermal expansion in the polysilicon layer. The displacement of actuator is analyzed to be proportional to the square of input voltage. These micro actuator technology can be utilized for the fabrication of MEMS (microelectromechanical system) such as micro relay, which requires large displacement or contact force but relatively slow response.

• Composites Research
• /
• v.16 no.2
• /
• pp.62-67
• /
• 2003

Interfacial properties and damage sensing for the carbon fiber/epoxy-amine terminated (AT)-polyetherimide (PEI) composite were performed using microdroplet test and electrical resistance measurements. As AT-PEI content increased, the fracture toughness of epoxy-AT-PEI matrix increased, and interfacial shear strength (IFSS) increased due to the improved fracture toughness by energy absorption mechanisms of AT-PEI phase. The microdroplet in the carbon fiber/neat epoxy composite showed brittle microfailure mode. At 15 phr AT-PEI content ductile microfailure mode appeared because of improved fracture toughness. After curing, the change in electrical resistance $\Delta\textrm{R}$) with increasing AT-PEI content increased gradually because of thermal shrinkage. Under cyclic stress, in the neat epoxy case the reaching time until same stress was faster and their slope was higher than those of 15 phr AT-PEI. The result obtained from electrical resistance measurements under curing process and reversible stress/strain was correspondence well with matrix toughness properties.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.1
• /
• pp.131-135
• /
• 2005

Under sulfur deprived conditions, PS II and photosynthetic $O_2$ evolution by Chlamydomonas reinhardtii UTEX 90 are inactivated, resulting in shift from aerobic to anaerobic condition. This is followed by hydrogen production catalyzed by hydrogenase. We hypothesized that the photosynthetic capacity and the accumulation of endogenous substrates such as starch for hydrogen production might be different according to cell age. Accordingly, we investigated (a) the relationships between hydrogen production, induction time of sulfur deprivation, increase of chlorophyll after sulfur deprivation, and residual PS II activity, and (b) the effect of initial cell density upon sulfur deprivation. The maximum production volume of hydrogen was 151 ml $H_2$/l with 0.91 g/l of cell density in the late-exponential phase. We suggest that the effects of induction time and initial cell density at sulfur deprivation on hydrogen production, up to an optimal concentration, are due to an increase of chlorophyll under sulfur deprivation.

• Journal of Korean Neurosurgical Society
• /
• v.50 no.5
• /
• pp.426-433
• /
• 2011

Objective : The Histoculture Drug Response Assay (HDRA), which measures chemosensitivity using minced tumor tissue on drug-soaked gelfoam, has been expected to overcome the limitations of in vitro chemosensitivity test in part. We analyzed interim results of HDRA in malignant gliomas to see if the test can deserve further clinical trials. Methods : Thirty-three patients with malignant gliomas were operated and their tumor samples were examined for the chemosensitivity to 10 chosen drugs by HDRA. The most sensitive chemotherapy regimen among those pre-established was chosen based on the number of sensitive drugs or total inhibition rate (IR) of the regimen. The response was evaluated by 3 month magnetic resonance image. Results : Among 13 patients who underwent total resection of the tumor, 12 showed no evidence of disease and one patient revealed progression. The response rate in 20 patients with residual tumors was 55% (3 complete and 8 partial responses). HDRA sensitivity at the cut-off value of more than one sensitive drug in the applied regimen showed a sensitivity of 100%, specificity of 60% and predictability of 70%. Another cut-off value of >80% of total IR revealed a sensitivity of 100%, specificity of 69%, and predictability of 80%. For 12 newly diagnosed glioblastoma patients, median progression-free survival of the HDRA sensitive group was 21 months, while that of the non-sensitive group was 6 months ($p$=0.07). Conclusion : HDRA for malignant glioma was inferred as a feasible method to predict the chemotherapy response. We are encouraged to launch phase 2 clinical trial with chemosensitivity on HDRA.

• Journal of Applied Biological Chemistry
• /
• v.60 no.3
• /
• pp.249-256
• /
• 2017

The Monascus azaphilone (MAz) pigment is a well-known food colorant that has yellow, orange and red components. The structures of the yellow and orange MAz differ by two hydride reductions, with yellow MAz being the reduced form. Orange MAz can be non-enzymatically converted to red MAz in the presence of amine derivatives. It was previously demonstrated that mppE and mppG are involved in the biosynthesis of yellow and orange MAz, respectively. However, ${\Delta}mppE$ and ${\Delta}mppG$ knockout mutants maintained residual production of yellow and orange MAz, respectively. In this study, we deleted the region encompassing mppD, mppE and mppG in M. purpureus and compared the phenotype of the resulting mutant (${\Delta}mppDEG$) with that of an mppD knockout mutant (${\Delta}mppD$). It was previously reported that the ${\Delta}mppD$ strain retained the ability to produce MAz but at approximately 10% of the level observed in the wildtype strain. A chemical analysis demonstrated that the ${\Delta}mppDEG$ strain was still capable of producing both yellow and orange MAz, suggesting the presence of minor MAz route(s) not involving mppE or mppG. Unexpectedly, the ${\Delta}mppDEG$ strain was observed to accumulate fast-eluting pigments in a reverse phase high-performance liquid chromatography analysis. A LC-MS analysis identified these pigments as ethanolamine derivatives of red MAz, which had been previously identified in an mppE knockout mutant that produces high amounts of orange MAz. Although the underlying mechanism is largely unknown, this study has yielded an M. purpureus strain that selectively accumulates red MAz.

• Analytical Science and Technology
• /
• v.23 no.4
• /
• pp.405-413
• /
• 2010

A new method for the simultaneous determination of six glucocorticoids (betamethasone, dexamethasone, prednisone, prednisolone, methylprednisolone, and flumethasone) in meats (bovine muscle, bovine liver) were established. Samples were effectively extracted using C18 cartridge with ethylacetate. Chromatographic separation was achieved using C18 column and negative electrospray ionization mass spectrometry was performed in the Multiple Reaction Monitoring mode for the effective quantitation and qualification of glucocorticoids. Acetonitrile and water (0.1% formic acid) were used as mobile phase and additive for effective electrospray ionization, and gave good chromatographic separation and mass spectrometric sensitivity. The limit of detection (LODs) and the limit of quantitation (LOQs) in spiked blank samples depending on types of matrix and pharmaceuticals were ranged from 0.2 to $1.0\;{\mu}g$/kg and 0.8 to $3.4\;{\mu}g$/kg, respectively. And the recoveries were between 89.5 to 119.6%. The established method showed good recoveries, accuracies, precisions and fast sample preparation and it will be applied to assay of glucocorticoids residues in meat.