• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.968-971
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• 2011

Leuconostoc genus, which comprise heterofermentative lactic acid bacteria, reduces fructose to mannitol by recycling intracellular NADH. To evaluate the mannitol productivities of different Leuconostoc species, 5 stock cultures and 4 newly isolated strains were cultivated in MRS and simplified media containing glucose and fructose (1:2 ratio). Among them, L. citreum KACC 91348P, which was isolated from kimchi, showed superior result in cell growth rate, mannitol production rate, and yield in both media. The optimal condition for mannitol production of this strain was pH 6.5 and $30^{\circ}C$. When L. citreum KACC was cultured in simplified medium in a 2 l batch fermenter under optimal conditions, the maximum volumetric productivity was 14.83 $g{\cdot}l^{-1}h^{-1}$ and overall yield was 86.6%. This strain is a novel and efficient mannitol producer originated from foods to be used for fermentation of fructose-containing foods.

• International Journal of Human Ecology
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• v.17 no.1
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• pp.39-51
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• 2016

This pilot study examined programs for early childhood education and care in three Chinese cities. The samples for this study were one university-based kindergarten, one private kindergarten (rural area), and one public kindergarten (urban area). Six types of instruments were used to assess early childhood education and care services regarding quality matters. Most questions asked were open-ended; consequently, the interview answers by kindergarten directors or teachers (as well as observations made by the researcher) formed the basis for collecting the data. Quality components for each program were determined by a comparison method. The comparison allowed the researcher to understand the range of quality education and care available as well as the variability of existing kindergarten programs in China. The findings of the investigation revealed important information on; (a) demographic information (fees, class hours, total weeks of class, vacation, number of children and staff, class size, and teacher-child ratio) (b) teacher characteristics, (c) health practices, (d) safety practices, (e) work environment, (f) physical settings, (g) play materials, (h) parent involvement, (i) nutrition, (j) daily schedule. Implications within the Chinese context for quality practices and issues to further develop and strengthen early childhood education and care systems are discussed.

• Advances in concrete construction
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• v.6 no.5
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• pp.485-507
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• 2018

Concrete-Filled Steel Tube (CFST) columns are an increasingly popular means to support great compressive loads in buildings. The residual strength capacity of CFST stub columns may be utilized to assess the potential damage caused by fire and calculate the structural fire protection for least post-fire repair. Ten specimens under room conditions and 10 specimens under fire exposure to the Eurocode smouldering slow-growth fire were tested to examine the effects of diameter to thickness D/t ratio and reinforcing bars on residual strength capacity, ductility and stiffness of CFST stub columns. On the other hand, in sixteen among the twenty specimens, three or six reinforcing bars were welded inside the steel tube. The longitudinal strains in the steel tube and load-displacement relationships were recorded throughout the subsequent compressive tests. Corresponding values of residual strength capacity calculated using AISC 360-10 and EC4 standards are presented for comparison purposes with the experimental results of this study. The test results showed that after exposure to $750^{\circ}C$, the residual strength capacity increased for all specimens, while the ductility and stiffness were slightly decreased. The comparison results showed that the predicted residual strength using EC4 were close to those obtained experimentally in this research.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.9
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• pp.1531-1538
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• 2003

This paper compiles solutions of plastic $\eta$ factors and crack tip stress triaxialites for standard and nonstandard fracture toughness testing specimens, via detailed three-dimensional (3-D) finite element (FE) analyses. Fracture toughness testing specimens include a middle cracked tension (M(T)) specimen, SE(B), single-edge cracked bar in tension (SE(T)) and C(T) specimen. The ligament-to-thickness ratio of the specimen is systematically varied. It is found that the use of the CMOD overall provides more robust experimental J estimation than that of the LLD, for all cases considered in the present work. Moreover, the J estimation based on the load-CMOD record is shown to be insensitive to the specimen thickness, and thus can be used for testing specimen with any thickness. The effects of in-plane and out-of-plane constraint on the crack tip stress triaxiality are also quantified, so that when experimental J value is estimated according to the procedure recommended in this paper, the corresponding crack tip stress triaxiality can be estimated. Moreover, it is found that the out-of-plane constraint effect is related to the in-plane constraint effect.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.34-40
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• 2013

Various depositional conditions, such as substrate, pressure, deposition time, temperature of substrate, power and gas composition, have mainly been studied to attain DLC films using RF sputtering system up to the current. In this study, the $N_2/Ar/CH_4$ gas mixture factored on characteristics of DLC deposited film such as structure, hardness, electrical property were investigated. The concentration of the $N_2$ gas in the sputtering gas may be a significant effect on the growth rate of the doped films, because nitrogen ions react not only with the carbon atoms on the target but also with $C_xH_y$ ions in the plasma on the substrate surface. It was seen from this experimental that the resistance of deposited film is decreased, and the relative intensity ratio of D to G peak is increased as nitrogen content of film deposition is increased.

• Proceedings of the Ginseng society Conference
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• 1980.09a
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• pp.59-69
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• 1980

A new HPLC-method for separation and quantitative determination of ginsenosides in Panax ginseng, Panax quinquefolium and in pharmaceutical drug preparations is elaborated. A reversed-phase-system with ${\mu}Bondapak\;C_{18}$ column (3.9 mm $I.D.{\times}30\;cm$) using acetonitrile-water (30:70) 2 ml/min and acetonitrile-water (18:82) 4 ml/min is suitable for the base-line separation of $Rb_1,\;Rb_2,\;Rc,\;Rd,\;Rf,\;Rg_2,\;respectively\;Re,\;Rg_1$ in 30 minutes. The ginsenosides are directly detected at 203 nm (without derivatization) with the LC-55 or LC-75 spectrophotometer (Perkin-Elmer) at $100\%$ transmission. Detection limit is 300 ng at a signal-to-noise ratio of 10:1. The ginsenosides-peak identification is carried out with HPTLC (high performance thin layer chromatography), with MIR-IR (multiple internal reflection-IR-spectros-copy) and with FD-MS (field desorption mass spectrometry). The calibration curve of each ginsenoside has a correlation coefficient very near to 1. Relative standard deviation for quantitative determinations depends upon the amount of ginsenosides and is approximately 1\%$ for ginsenoside contents of 1\%$. This method is adaptable for routine analysis in quality control laboratories.

• Nuclear Engineering and Technology
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• v.48 no.1
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• pp.200-210
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• 2016

The neutron radiography reactor (NRAD) is a 250 kW Mark-II Training, Research, Isotopes, General Atomics (TRIGA) reactor at Idaho National Laboratory, Idaho Falls, ID, USA. The East Radiography Station (ERS) is one of two neutron beams at the NRAD used for neutron radiography, which sits beneath a large hot cell and is primarily used for neutron radiography of highly radioactive objects. Additional fuel elements were added to the NRAD core in 2013 to increase the excess reactivity of the reactor, and may have changed some characteristics of the neutron beamline. This report discusses characterization of the neutron beamline following the addition of fuel to the NRAD. This work includes determination of the facility category according to the American Society for Testing and Materials (ASTM) standards, and also uses an array of gold foils to determine the neutron beam flux and evaluate the neutron beam profile. The NRAD ERS neutron beam is a Category I neutron radiography facility, the highest possible quality level according to the ASTM. Gold foil activation experiments show that the average neutron flux with length-to-diameter ratio (L/D) = 125 is $5.96{\times}10^6n/cm^2/s$ with a $2{\sigma}$ standard error of $2.90{\times}10^5n/cm^2/s$. The neutron beam profile can be considered flat for qualitative neutron radiographic evaluation purposes. However, the neutron beam profile should be taken into account for quantitative evaluation.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.79-81
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• 2007

To detect partial discharge of 154kV joint box, we have made experiment by using the Al-foil electrode sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied with both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we had used Al-Foil sensor on middle joint box of 154[kV] underground transmission power cable, and then analyzed reliability of calibration signal by using the Al-Foil electrode sensor of NJB. From above results, decrement properties measured highly. But incase of injecting calibration signal of 500[pC] after measuring signals in IJB, the S/N ratio had about 25[dB] acquisition.

• Journal of Power Electronics
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• v.2 no.2
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• pp.146-153
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• 2002

this paper presents an implementation of digital control system of speed sensorless for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The problem of DTC for high-dynamic performance RSM drive is generating a nonlinear torque due to a saturated nonlinear inductance curve with various load currents. The control system consists of stator flux observer, compensating inductance look-up table, rotor position/speed/torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source unverter, and TMS320C31 DSP controller. The stator flux observer is based on the combined voltage and current model with stator flux feedback adapitve control that inputs are the compensated inductances, current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated rotor speed is determined by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operation area. It does not requrie the knowledge of any montor paramenters, nor particular care for moter starting, In order to prove the suggested control algorithm, we have simulation and testing at actual experimental system. The developed sensorless control system is showing a good speed control response characterisitic result and high performance features in 20/1500 rpm with 1.0Kw RSM having 2.57 ratio of d/q reluctance.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.122-134
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• 1995

The present study was investigated combustion characteristics of methane-air mixtures at stratified charge in a constant volume combustion chamber. The main results obtained from this study can be summarized as follows. In case of ${\phi}_s=1.0$, total burning times greatly affected rather than initial time of pressure increase and maximum combustion pressure. In case of ${\phi}_t=1.0$, initial time of pressure increase and total burning times were affected considerably in comparison with the case of ${\phi}_s=1.0$. Also, even the very lean mixture which total equivalence ratio is ${\phi}_t=0.69$(${\phi}_s=1.0$, ${\phi}_m=0.65$), by changing configuration of the critical passage-hole and using a stratified mixture, it is possible to decrease substantially the initial time of pressure increase. total burning times and NOx concentration without deteriorating combustion characteristics such as maximum combustion pressure, rate of heat release etc. in comparison with the use of single chamber(in case of ${\phi}=1.0$) only. Specifically, our trends were revealed remarkably in the case of Type D which is reduced a flame contact area of sub-chamber side of the passage-hole.