• Proceeding of EDISON Challenge
• /
• 2016.03a
• /
• pp.140-146
• /
• 2016

Using density functional Theory, we studied local structure of liquid ethylene glycol and 1,3-propanediol. For both liquid, making intramolecular hydrogen bonding is not preferred, because relative energy between with and without intramolecular hydrogen bond is only -1.95kcal/mol, which is far less than intermolecular hydrogen bonding energy, about -7.5kcal/mol. Also, hydrogen bond induce polarization of hydroxyl group and make $2^{nd}$ hydrogen bond more stronger. This effect was small in intramolecular hydrogen bond of ethylene glycol. When considering energy per hydrogen bond, making only one intermolecular hydrogen bond for ethylene glycol pair is energetically favored, while two intermolecular hydrogen bond can be formed in 1,3-propanediol pair.

• Journal of Power System Engineering
• /
• v.18 no.6
• /
• pp.200-206
• /
• 2014

This paper deals with deterministic PI controller design based on dynamic characteristics for refrigeration system. The temperature control system of an oil cooler is described as a typical 2nd order model of the refrigeration system which has zeros in a transfer function. PI controller gains satisfying control specifications are represented by the dynamic characteristic functions using relationship between the parameters and the control specifications in the model. Phase margin was considered to increase robustness of the oil cooler control system. Furthermore, the influence of zeros in the model to the control specifications was analyzed in detail for improving control performance. The validity of the suggested PI controller design was investigated using the four types of gains which had been already confirmed their control performances through experiments.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2008.05a
• /
• pp.431-434
• /
• 2008

Effects of microstructure on the toughness of low carbon HSLA steels were investigated. Nickel decreased the ferrite-austenite transformation temperature, resulted in increase of the fraction of bainitic ferrite. However, it was decreased with increasing deformation amount at austenite region. Since fine austenite grains formed by dynamic recrystallization under large strain transformed to acicular ferrite or granular bainite rather than bainitic ferrite. The effective grain size, thus, was decreased by deformation and it resulted in lower ductile-brittle transition temperature (DBTT). The bainitic ferrite was thought to inhibit the fracture crack initiation and to delay the crack propagation by its high dislocation density and hard interlath $2^{nd}$ phase constituents, respectively. Thus, DBTT was also decreased by Ni addition in low carbon HSLA steels.

• Journal of the Korean Society for Railway
• /
• v.10 no.3 s.40
• /
• pp.355-364
• /
• 2007

Recently a concrete slab tracks are being constructed on roadbed in the Gyoeng-bu 2nd phase high speed railways. In respdnding to this trend, new design standards and track materials maintenance systems, based on the slab track material safety and usage perspective, are needed. This research provides a roadbed design criteria and the maintenance system. The proposed roadbed design criteria and the maintenance system are based on the developed analysis meathod of train/slab-track interaction. where the roadbed settlement and train speed are utilized as mediating variables. In the analysis, the dynamic response of train/slab-track interaction apply to various speeds and settlements. the roadbed settlement is shown in a sinusoidal shape of wave, the scope of the settlement occurrence presented in its wavelengths, include 6meters, 10meters, 15merwes, 20meters, 30meters. The train speeds involved are 50, 100, 150, 200, 250, 300, 350, 400kilometers per hour.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.24 no.3
• /
• pp.376-380
• /
• 1987

The closed-loop transfer function of 2-nd order PLL (phase-looked loop)of which loop filter has active-lag 1-st order is found. Considering the three criteria of system performance: the transient response time of the circuit, noise bandwidth by the linear analysis and stability which uses root-locus method, the optimum value of damping factor is 1.0 and the natural frequency which depends upon the signal frequency can be determined after consideration of the trade-off relationship between the transient response time and the noise bandwidth.

• Journal of Korean Society of Water and Wastewater
• /
• v.25 no.4
• /
• pp.527-534
• /
• 2011

In this research, the photocatalytic degradation of dibenzothiophene (DBT) in $TiO_2$ aqueous suspension has been studied. $TiO_2$ photocatalysts are prepared by a sol-gel method. The dominant anatase-structure on $TiO_2$ particles is observed after calcining the $TiO_2$ gel at $500^{\circ}C$ for 1hr. Photocatalysts with various transition metals (Nd, Pd and Pt) loading are tested to evaluate the effect of transition metal impurities on photodegradation. The photodegradation efficiencies with $TiO_2$ including Pt and Pd are higher than pure $TiO_2$ powder. Also we investigated the applicability of $H_2O_2$ to increase the efficiency of the $TiO_2$ photocatalytic degradation of dibenzothiophene. The degradation efficiency increases with increasing dosage of $H_2O_2$ in the range of 0.01M to 0.1M . The effect of pH is investigated; we obtained the maximum photodegradation efficiency at pH 5. In addition, the intermediate analysis found dihydroxyl -dibenzothiophene as a reaction intermediate of dibenzothiophene during the photodegradation.

• Women's Health Nursing
• /
• v.8 no.4
• /
• pp.538-549
• /
• 2002

This study was designed to test the effects of a full body massage on uterine contraction, length of labor, type of delivery, and drug intervention for primipara during labor. Data were collected using a quasi-experiment method (nonequivalent control group, pre-post test design) from November 1, 2001 to July 31, 2002. The subjects of this experiment consisted of 28 women in the experimental group and 29 in the control group, out of 57 primipara hospitalized at the U OB & GYN hospital in Inchon. The experimental group was given a 20 minute full body massage for each of the three delivery phases (latent, active, and transition). The control group was given conventional delivery care. Three (3) parameters were analyzed in this experiment. (1) The interval, duration, and strength of uterine contraction, using an electric tocodynamometer (2) The elapsed time for stage 1 and stage 2 labor. (3) The types of deliveries and drug interventions, using postpartum medical records The data collected were analyzed using the repeated measures analysis of variance (ANOVA), t-test, and $x^2$ test of the SPSS program. The results of the experiment are as follows: 1) Uterine contraction interval was significantly reduced (F=3.210, p=.050). Duration of uterine contraction showed significant increase only during the transition phase (t=-2.319, p=.023). Strength of uterine contraction showed no significant difference. 2) Total length of labor was significantly shortened (t=-5.245, p=.000). The length of 1st stage labor was significantly shortened (t=-5.164, p=.000), with latent phase showing (t=-4.709, p=.000), active phase (t=-2.973, p=.005), and transition phase (t=-2.031, p=.047). The length of 2nd stage labor showed no significant difference. 3) The number of natural deliveries were significantly increased ($x^2$=13.127, p=.004). 4) The number of drug interventions were significantly fewer ($x^2$= 4.493, p=.034). In conclusion, this study shows that a full body massage has a significantly positive effect on uterine contraction interval, length of labor, type of delivery, and drug intervention. Therefore, this study suggests that a full body massage be used clinically to help primipara during labor.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.9 no.4
• /
• pp.192-197
• /
• 2009

This paper presents the design and measurement of a 2.4/5.2-GHz dual band VCO with a balanced frequency doubler in $0.18\;{\mu}m$ CMOS process. The topology of a 2.4 GHz VCO is a cross-coupled VCO with a LC tank and the frequency of the VCO is doubled by a frequency balanced doubler for a 5.2 GHz VCO. The gate bias matching network for class B operation in the balanced doubler is adopted to obtain as much power at 2nd harmonic output as possible. The average output powers of the 2.4 GHz and 5.2 GHz VCOs are -12 dBm and -13 dBm, respectively, the doubled VCO has fundamental harmonic suppression of -25 dB. The measured phase noises at 5 MHz frequency offset are -123 dBc /Hz from 2.6 GHz and -118 dBc /Hz from 5.1 GHz. The total size of the dual band VCO is $1.0\;mm{\times}0.9\;mm$ including pads.

• Korean Journal of Agricultural Science
• /
• v.44 no.2
• /
• pp.254-260
• /
• 2017

The primary goals of this research were to evaluate the impact of diet supplemented with 25-hydroxyvitamin $D_3$ ($Hy{\cdot}D(R)$) on sow's body condition and reproduction performance. A total of sixteen multiparous sows [(Landrace ${\times}$ Yorkshire), average parity = $3.79{\pm}0.32$] and their litters were randomly allotted to 2 treatments to give 8 replicates per treatment. Diet treatments were randomized to receive a non-active (ND) or active 25-hydroxyvitamin $D_3$ (AD) diet (0.36 mg cholecalciferol/g) during pregnancy. The results of this experiment were observed at the gestation of d 58 - 75, d 76 - 95, d 96 - 110, and d 111 - 115. A corn-soybean meal-based diet was formulated to meet or exceed the nutrient requirements recommended by NRC (2012). Results indicated that the sows' farrowing duration was shortened (4.71, 5.38 h), and the average number of mummified fetuses decreased significantly (p < 0.05) in AD treatment compared with ND treatment (0.1, 0.5) while birth weight was significantly (p < 0.05) improved (1.44, 1.18 kg). There were no significant effects on body weight, backfat thickness, and fecal score during the gestation of sows in different phases (p > 0.05). And the total birth, stillbirth, live birth, and survival rates of the litter did not change (p > 0.05). The results of this study suggest that the farrowing duration of sow pigs will be shortened and the number of mummies will be decreased while their litters' body weight may be improved, if fed active 25-hydroxyvitamin $D_3$ (0.36 mg/g) during pregnancy phase.

• Journal of Welding and Joining
• /
• v.17 no.1
• /
• pp.133-144
• /
• 1999

To fine seam annealer capacity of through thickness seam annealing in terms of through thickness microstructure change with increased toughness and elongation leaving heat trace on it, high strength steel pipes of ERW with different thickness were tested in different seam annealing temperature measured on the outer surface of pipes. Annealing temperature and microstructure of the weld seam were changed through applied seam annealing condition. Toughness and tensile test with hardness and microstructure analysis were done on the annealed weld seam to fine its characteristics as a primary step and annealing characteristics according to different seam annealing condition. Through a study of annealed ERW weld seam characteristics and seam annealing technology, amount of electric power should apply in decreased manner to arranged inductors of annealer in the order of 1st, 2nd, 3rd, so on for proper seam annealing. For example of 15.4mm thick and 610mm outside diameter pipe, applied power for proper seam annealing is 600 -650kw at 1st inductor, 450 - 500kw at 2nd inductor, 200-250 kw at 3rd inductor of annealer during 10 - 12M/minute moving speed of pipe. Also, the penetration depth of heat trace along the thickness direction of weld during seam annealing can be estimated through the equation 17mm/kv$\times$voltage(kv) with the microstructure and hardness analysis of thick weld seam as well as study of seam annealing and comparison of cooling condition to CCT diagram of low carbon high strength steel. From this result, the difference between the technological applicability of full annealing condition based on phase diagram and full penetration of heat trace based on CCT diagram along the thickness of weld seam is discussed.