• Transactions of the Korean hydrogen and new energy society
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• v.30 no.1
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• pp.67-75
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• 2019

An experimental study was conducted to measure laminar burning velocity and Markstein length of SNG fuel with 3% of hydrogen contents from spherical propagating flames at normal and elevated initial pressure. These results were compared with numerical calculations by Premix code with GRI-mech 3.0, USC II and UC San Diego to provide suitable mechanism for SNG fuel. As a result of this work, it was found that the burning velocities and Markstein lengths of SNG fuel decrease with increase of initial pressure regardless of equivalence ratio. In addition, numerical calculations with GRI-mech 3.0 were coincided with experimental results.

• Korean Journal of Culture and Social Issue
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• v.25 no.4
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• pp.305-323
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• 2019

The Satisfaction With Life Scale (SWLS) is the most widely used instrument to measure life satisfaction. This study examined the factor structure and measurement equivalence of SWLS across age and gender in Korea. A total of 936 data were analyzed, comprising 433 college students (195 males and 238 females) and 503 middle-aged adults (237 males and 266 females). The results are as follows. Firstly, the data supported a modified single-factor model with correlations between error variances of items 4 and 5. Therefore, items 4 and 5 reflecting the past were found to share a distinct meaning with other items. Secondly, SWLS showed full strict invariance by gender, but only showed partial strict invariance between college students and middle-aged adults. These results indicate that meaningful comparisons of SWLS scores across gender may be valid, but careful attention should be paid when comparing age groups.

• Journal of Korean Academy of Nursing
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• v.42 no.1
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• pp.76-84
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• 2012

Purpose: The purpose of this methodological study was to examine the reliability and validity of a translated Korean version of the Critical Care Pain Observation Tool (CPOT) developed for assessment of pain in critically ill nonverbal patients. Methods: A cross-sectional study design was used. Data were collected from a convenience sample of 202 critically ill patients admitted to a university hospital. Upon establishment of content and translation equivalence between the English and Korean version of CPOT, psychometric properties were evaluated. Results: The interrater reliability was found to be acceptable with the weighted kappa coefficients of .81-.88. Significant high correlations between the CPOT and the Checklist of Nonverbal Pain Indicators were found indicating good concurrent validity (r=.72-.83, p<.001). Data showed the area under the ROC curve of 0.86 with a cut-off point of 1, which resulted in 76.9% sensitivity and 88.6% specificity. The mean score of CPOT during suctioning was significantly different from that of before (t= -14.16, p<.001) or 20 minutes after suctioning (t=16.31, p<.001). Conclusion: Results of this study suggest that the CPOT can be used as a reliable and valid measure to assess pain in critically ill nonverbal patients.

• Child Health Nursing Research
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• v.14 no.2
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• pp.138-145
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• 2008

Purpose: This study, using a pre-posttest design of non-equivalence comparative groups, was done to determine effects of KC (kangaroo care) on weight and SH (stress hormone) of premature infants. Method: Participants were 31 premature infants assigned to KC(14) or CG(control group)(17). Data were collected from June 2006 to February 2007. KC was given for 60 minutes at a time, Mon, Wed, and Fri for a 10 times. Body weight was measured at a fixed time daily and serum cortisol was examined as part of routine blood testing, frequent for premature infants. Results: The weight for infants in the KC group was higher than the control. The difference was significant between both the two groups, and the 2 measurement times(F=12.7, p=.001). SH(cortisol) in infants of KC group decreased than CG, but there was no valid difference from the statistical viewpoint. Conclusion: The result of the study suggest that KC contributes to weight increase in premature infants and also that KC is effective for SH reduction in spite of the lack of statistical validity. Therefore, our conclusion is that KC can be used as an independent nursing intervention for development and advance of premature infants.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.9
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• pp.1110-1116
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• 2004

Experimental measurements of laser-induced ion mobility(LIIM) were performed for ethene/air premixed flames operated near the soot inception point. Soot was ionized using a pulsed laser operated at 532 nm. The ionization signal was collected with a tungsten electrode located in the post-flame region. ionization signals were collected using both a single electrode and dual electrode configuration. Prior LIIM studies have focused on the use of a single biased electrode to generate the electric field, with the burner head serving as the path to ground. In many practical combustion systems, a path to ground is not readily available. To apply the LIIM diagnostic to these geometries, a dual electrode geometry must be employed. The influence of electrode configuration, flame equivalence ratio, and flame height on ionization signal detection was determined. The efficacy of the LIIM diagnostic to detect soot inception in the post-flame region of a premixed flame using a dual electrode configuration was investigated. For the different dual electrode configurations tested, the dual parallel electrode geometry was observed to be most sensitive to detect the soot inception point in a premixed flame.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.143-148
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• 2001

We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature, CO values were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$ and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.300-310
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• 1999

A constant-volume combustion chamber is developed to measure the burnt gas temperature over the wide ranges of equivalence ratio from 1.5 to 2.7 and pressure from 0.1 to 2.7 and pressure from 0.1 to 6 MPa by two-color method. The combustion temperature is also calculated by the conventional two-region model. The premixed fuel rich propane-oxygen-inert gas mixtures under high pressures are simultaneously ignited by eight spark plugs located on the circumference of combustion chamber with 45 degree intervals. The eight converging flames compress the end gases to high pressures. The transmissiv-ity in the chamber center during the final stage of combustion at the highest pressure is measured by in situ laser extinction method. Comparisons are made with the combustion temperatures between two-color method and two-region model. It is found that the burnt gas temperature mea-sured by two-color method is higher than that calculated by two-region model because of being the negative temperature gradient on the calculation and the temperature distribution of light path-length on the measurement and the burnt gas temperature for the turbulent combustion is higher than that of the laminar combustion under the same conditions because the heat loss for turbulent combustion is lower due to the shorter combustion period.

• Journal of the Korean Society of Combustion
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• v.7 no.2
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• pp.15-23
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• 2002

We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature. CO concentration were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$, and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.911-917
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• 2018

Influence of the adaptors on the calibration of $100{\mu}H$ inductance standard was studied as a function of torque, applied when tightening the standard inductor terminal with the adaptor. Two different homemade adaptors of BPO gold-plated brass (BPO-Au) and banana-copper (BN-Cu) were made for the connection between the LCR meter and the inductance standard. The measured inductance (L) of the standard inductor and the contact resistance ($R_C$) between the adaptor and the standard inductor terminal showed exponential decreases against the torque increase from $25cN{\cdot}m$ to $150cN{\cdot}m$. The measured L and the calculated equivalence series resistance ($R_S$) were dependent on the adaptor type as well as on the $R_C$. The results of the adaptor analysis imply that the BPO-Au adaptor with the lower $R_C$ is more suitable for the inductance calibration. The calculated inductance of $99.956{\mu}H$ corrected by subtraction of the adaptor inductance and the contact resistance contributions from the measured value using the BPO-Au adaptor agreed well with the certificate ($99.948{\mu}H$) of the PTB within the measurement uncertainty of $140{\mu}H/H$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.3 s.234
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• pp.376-383
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• 2005

In the paper we investigate characteristics of a transitional behavior from a premixed flame to a triple flame in a lifted flame according to the change of equivalence ratio. In previous study, we showed that the stabilized laminar lifted flame regime is categorized by regimes of premixed flame, triple flame and critical flame. A gas-chromatograph is used to measure concentration field, a smoke-wire system is used to measure streak line, and a PIV system is used to measure velocity field in lifted flame. In the visualization experiment of smoke wire, the flow divergence and redirection reappeared in premixed flame as well as triple flame. Thus we cannot express the flame front of lifted flame has a behavior of triple flame with only flow divergence and redirection. In PIV measurement, flow velocity for those three flames has minimum value at the tip of flame front. To differentiate triple flame and premixed flame, $\Phi$ value of partially premixed fraction is employed. The partially premixed fraction $\Phi$ was constant in premixed flame. In critical flame small gradient appears over the whole regime. In triple flame, typical diffusion flame shape is obtained as parabolic distribution type due to diffusion flame trailing.