• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.6
• /
• pp.95-104
• /
• 2003

The electric traction systems are quite differ from general power systems which is single-phase and heavy load. Therefore, there are inevitably power quality problems such as steady state or transient voltage drop, voltage imbalance and harmonic distortion. Among these problems, since steady-state volatge drop is the one of most important factor in electric power quality, many researches about on the compensation of volatge drop by using SVC(Static Var Compensator) and/or STACOM(Static Compensator) have been studied and proposed Also, it is expected that transient voltage drop(voltage sag) could affect the control and safety of high speed traction load. In this paper, voltage sag compensation of AT(Auto Transformer) feeding system are studied The detailed transient models of utility source, scott transformer, AT, and traction load are estabilished. The application of DVR(Dynamic Voltage Restorer) in electric traction system is proposed to compensate the voltage sag of traction network which is occured by the fault of utility source. It can be shown that application of the DVR in electric traction system is very useful to compensate the volatge sag from the result of related simulation works.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.6 no.1
• /
• pp.43-50
• /
• 1986

A research was performed to examine the applicability of aerobic fixed-biofilm reactors for removal of biodegradable organics in raw waters. Crushed briquette ashes or granite were utilized as media. Experiments were carried out by feeding packed bed reactors with a synthetic raw water prepared by dissolving phenol in tap water with other inorganic nutrients. Results of the research showed that the effluent TBOD concentrations were lower than 6 mg/l when the influent BOD concentrations were kept below 50 mg/l and a detention time of about 2.7 hours was provided. The SBOD concentrations of the treated waters should be less than 5 mg/l since the effluent SS could be removed by conventional water treatment methods such as coagulation and filtration. It was also found that most of the SS in the effluents were humic materials since the effluent SS caused little BOD. This means the biofilm in the reactor was in endogenous respiration phase due to low F/M ratio. According to the results of this study, it is recommended to pretreat any raw water contaminated with biodegradable organics in an aerobic fixed biofilm reactor with a detention time of 2 to 3 hours.

• Asian-Australasian Journal of Animal Sciences
• /
• v.25 no.11
• /
• pp.1568-1574
• /
• 2012

Three Holstein steers in the growing phase, each with a ruminal cannula, were used to test the hypothesis that the synchronization of the hourly rate of carbohydrate and nitrogen (N) released in the rumen would increase the amount of retained nitrogen for growth and thus improve the efficiency of microbial protein synthesis (EMPS). In Experiment 1, in situ degradability coefficients of carbohydrate and N in feeds including Korean rice wine residue (RWR) were determined. In Experiment 2, three total mixed ration (TMR) diets having different rates of carbohydrate and N release in the rumen were formulated using the in situ degradability of the feeds. All diets were made to contain similar contents of crude protein (CP) and neutral detergent fiber (NDF) but varied in their hourly pattern of nutrient release. The synchrony index of the three TMRs was 0.51 (LS), 0.77 (MS) and 0.95 (HS), respectively. The diets were fed at a restricted level (2% of the animal's body weight) in a $3{\times}3$ Latin-square design. Synchronizing the hourly supply of energy and N in the rumen did not significantly alter the digestibility of dry matter, organic matter, crude protein, NDF or acid detergent fiber (ADF) (p>0.05). The ruminal $NH_3$-N content of the LS group at three hours after feeding was significantly higher (p<0.05) than that of the other groups; however, the mean values of ruminal $NH_3$-N, pH and VFA concentration among the three groups were not significantly different (p>0.05). In addition, the purine derivative (PD) excretion in urine and microbial-N production (MN) among the three groups were not significantly different (p>0.05). In conclusion, synchronizing dietary energy and N supply to the rumen did not have a major effect on nutrient digestion or microbial protein synthesis (MPS) in Holstein steers.

• Asian-Australasian Journal of Animal Sciences
• /
• v.25 no.4
• /
• pp.569-576
• /
• 2012

Two experiments were conducted to investigate the potential for Forsythia suspensa extract (FSE) to substitute for antibiotic in broiler chicken. First, a well-diffusion assay procedure and a 2-fold dilution method were used to determine the bacteriostatic activity of FSE on Escherichia coli K88, staphylococcus aureus, and salmonella was assayed. An inhibitory effect of FSE was observed on the growth of these bacteria. This effect seems to be dose depended, which disappeared after 25.00, 12.50, 1.56 mg/ml. Second, a 42-d trial with 252 broiler chickens (d 1, $38.7{\pm}1.1$ g BW) was conducted to evaluate the effect of dietary supplementation of FSE in broiler chicken. The feeding program consisted of a starter diet from d 1 to 21 and a finisher diet from d 22 to 42. Dietary treatments included were: i) NC: negative control fed a corn-soybean meal based diet; ii) PC: positive control group fed based diet with chlortetracycline; and iii) FC: a test group fed with 100 mg FSE/kg diet. In this study growth performance did not differ among treatments during the starter period. However, dietary supplemental chlortetracycline and FSE increased (p<0.05) average daily gain (ADG), average daily feed intake (ADFI) compared with NC during the finisher and overall phase. Apparent digestibility of calcium on d 21, digestibility of energy and calcium on d 42 of FC was greater (p<0.05) than NC. Moreover, cecal Escherichia coli counts for birds from FC were lower (p<0.05) than NC. Dietary FSE supplementation also improved (p<0.05) villus height and villus height to crypt depth ratios in both duodenum and ileum and decreased (p<0.05) crypt depth in the duodenum. Duodenum villus height and villus height to crypt depth ratio in both duodenum and ileum from the FC group were also greater (p<0.05). Serum growth hormone and IGF-1 were not influenced by different treatments. Apparently, FSE has the potential to substitute for antibiotic in broiler chicken.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.1
• /
• pp.25-30
• /
• 2011

We investigated the effect of a lactic acid extract of Sargassum horneri (ExSL) as a calcium supplement on bone formation in 48 female Sprague-Dawley rats for 4 weeks of their growth phase. The rats were divided into four groups based on diet: two calcium-sufficient and two calcium-deficient diets. The normal control group (NC) was fed AIN-93G; the NCS group was fed the same diet containing 1% extract; the calcium-deficient control (DC) diet was based on AIN-93G; and the DCS group received the same calcium-deficient diet plus 1% extract. Bone formation in the rats was evaluated using the wet weight, length, diameter, and bone mineral density (BMD) of the femur. Serum parameters were also examined. The food intake among the groups did not differ significantly (P<0.05). The NCS group gained the most body weight, while the DC group gained much less weight than the other groups. The feeding efficiencies of the groups that received the extract (NCS and DCS) were slightly higher than those of the control groups (NC and DC). The calcium intakes of all groups depended on the amount of calcium in the feed; the NCS and DCS diets contained 12.15 mg more calcium than the NC and DC diets. The calcium absorption was lower in NCS than in DC and DCS, but significantly higher than in NC (P<0.05). The BMDs in the calcium-sufficient groups were not significantly different (P<0.05), while in the calcium-deficient groups the BMD was significantly higher in DCS than in DC (P<0.05). The serum calcium and phosphorus levels in all groups were not associated with markers of bone growth related to the extract. The osteocalcin content and alkaline phosphatase (ALPase) activity were higher in the calcium-deficient groups than in the normal groups (P<0.05). Ultimately, the osteocalcin content and ALPase activity were lower in DCS compared to DC. These results suggest that the addition of ExSL promotes bone formation and calcium absorption in growing rats.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.1
• /
• pp.101-106
• /
• 1992

Secretory patterns of serum tri-iodothyronine, thyroxin and testosterone were analysed by specific radioimmunoassay in Kaghani (n = 42), Rambouilet (n = 42) and Kaghani ${\times}$ Rambouillet (n = 42) male sheep to determine age and breed related changes. Animals were examined at 1-2 wk, 8, 10, 12, 20, 22 and 24 months of age (n = 6/age group). All animals were maintained under standard conditions of feeding and management. $T_3$ and $T_4$ concentrations were maximal (p < 0.01) in 1-2 wk old lambs of all breeds studied ($207.4{\pm}14.9-276.8{\pm}20.4ng/dl$ and $5.76{\pm}0.3-7.23{\pm}0.9{\mu}g/dl$, respectively). For all the breeds, concentrations of $T_3$ declined markedly (p < 0.01) at 8 month of age and then varied in a narrow range ($44.5{\pm}14.0-87.0{\pm}4.8ng/dl$) up to the age of 24 month. While, serum $T_4$ concentrations decreased (p < 0.01) to nadir ($0.97{\pm}0.1-1.43{\pm}0.3{\mu}g/dl$) at 10 months of age in all the 3 breeds. Afterwards, $T_4$ levels increased gradually and attained a small peak at 20 months before declining again at 22 and 24 months of age. Serum $T_3$ and $T_4$ concentrations were correlated significantly (p < 0.05) and their ratio was constant at all ages in the different breeds. Age significantly (p < 0.01) influenced the secretion of testosterone in the breeds examined but the breed differences were comparable. Mean serum concentrations of testosterone were low from 1-2 wk to 10 months of age in the Kaghani, Rambouillet and Kaghani ${\times}$ Rambouillet animals. Peak testosterone levels were noted in the 12 months old Kaghani ($1.75{\pm}0.4ng/ml$), Rambouillet ($1.30{\pm}0.2ng/ml$) and their $T_3$ cross animals ($1.16{\pm}0.08ng/ml$). Mean testosterone levels, thereafter, decreased at 20 months and then at 22 and 24 months remained variable but higher than observed at 1-2 wk -10 months of age. The findings of the present study indicate a significant influence of age but not of breed on the peripheral concentrations of thyroid hormones and testosterone. Serum concentrations of $T_3$ and $T_4$ were not related to testosterone levels. High thyroid secretory activity observed at prenatal phase of development may play an important role in preparing the lambs to extrauterine environments.

• Korean Parent-Child Health Journal
• /
• v.4 no.1
• /
• pp.35-55
• /
• 2001

Recently attention has been focused on the effects of early intervention, or its lack, on both normal and preterm infants. Particularly numerous studies suggest that premature infants are not necessarily understimulated but instead are subjected to inappropriate stimulation. Developmental support and sensory stimulation have become clinical opportunities in which nursing practice can impact on the neurobehavioral outcome of premature infants. Developmental care has been widely accepted and implemented in neonatal intensive care units across the country. Increasingly, attention and concern in caring for low-birth-weight infants and premature infants has led clinicians in the field to explore the effects of a complex of interventions designed to create and maintain a developmentally supportive environment; to provide age-appropriate sensory input; and to protect the infant from inappropriate, excessive and stressful stimulation. The components of developmental care include modifications of the macro-environment to reduce NICU light and sound levels, care clustering, nonnutritive sucking, and containment strategies, such as flexed positioning or swaddling. Sensory stimulation of the premature infants is presented to standardize the modification of a developmental intervention based on physiologic and behavioral cues. The most appropriate type of stimuli are those that are sensitive to infant cues. Evaluation of infant physiological and behavioral responds to specific intervention stimuli may help to identify more appropriate interventions based on infants' cues. A critical question confronting the clinician is that of determining when the evidence supporting a change in practice is sufficient to justify making that change. There are acknowledged limitations in the current studies. Many of the studies examined had small sample sizes; used nonprobability sampling; and used a phase lag design, which introduces the possibility of threats to internal validity and limits the generalizability of the results. Although many issues regarding the effects of developmental interventions remain unresolved, the available research base documents significant benefits of developmental care for LBW infants in consistent outcomes, without significant adverse effects. Particularly, although the individual studies vary somewhat in the definition of specific outcomes measured, instrumentation used, time and method of data collection, and preparaion of the care providers, in all studies, infants receiving the full protocol of individualized developmentally supportive care had improvements in some aspect of four areas of infant functioning: level of respiratory or oxygen support, the establishment of oral feeding; length of hospital stay, and infant behavioral regulation. In summary, based on the available literature, individualized developmental intervention should be incorporated into standard practice in neonatal intensive care. And this implementation needs to be coupled with ongoing research to evaluate the impact of an individualized developmental care programs on the short- and long-tenn health outcomes of LBW infants.

• Journal of Animal Science and Technology
• /
• v.57 no.10
• /
• pp.37.1-37.9
• /
• 2015

This study was performed to investigate the effects of the low plane of nutrition on growth and meat quality of finishing pigs. A total of 136 crossbred barrows and gilts weighing approximately 55 kg were allotted to 8 pens, with 17 animals housed per pen, in a 2 (sex) ${\times}$ 2 (nutrition) factorial arrangement of treatments. The animals allotted to a medium plane of nutrition (MPN) received a finisher phase 1 (P1) diet containing 3.47 Mcal DE/kg and 0.92 % lysine and a P2 diet containing 3.40 Mcal DE/kg and 0.78 % lysine for 35 d and 36/43 d, respectively; the animals allotted to the low plane of nutrition (LPN) received only a P2 diet containing 3.00 Mcal DE/kg and 0.68 % lysine 7 d longer than MPN. The animals were slaughtered following the feeding trial, after which the loin, ham, Boston butt, and belly were taken from a total of 24 animals, with the average live weight being 120 kg, and their physicochemical and sensory quality traits were analyzed. Average daily gain did not differ between MPN and LPN during either P1 or P2. Average daily feed intake was greater (P < 0.05) in LPN vs. MPN during both phases whereas the opposite was true for the gain:feed ratio. Backfat thickness (BFT) was less in LPN vs. MPN (21.7 vs. 24.1 mm at 115 kg). The plane of nutrition influenced no effect on any of the physicochemical characteristics of fresh loin, ham, or Boston butt analyzed in the present study. Fresh hams from LPN exhibited superior aroma and odor scores than those from MPN; however, sensory quality traits were not influenced by the plane of nutrition in other fresh primal cuts or cooked meat. Instead, fresh primal cuts and cooked meat from gilts rendered superior physicochemical characteristics and sensory scores, respectively, than those from barrows. Results suggest that the low plane of nutrition may be useful to increase the slaughter weight of finishing pigs with a moderately high BFT by virtue of its BFT-lowering effect with or without exerting a slightly positive influence on pork quality.

• Korean journal of applied entomology
• /
• v.50 no.4
• /
• pp.257-265
• /
• 2011

To investigate host preferencse of Myzus persicae on 15 sweet pepper cultivars grown in Jeonnam Province, EPG (electrical penetration graph) and life table experiments were carried out in the laboratory. Phloem phase times were significantly longer on Ferrari, Jinju, Debla, and Rapido than Orobell and Thialf. Non-penetration times were conversely observed. Life span, reproduction period, total fecundity, and intrinsic rate of increase ($r_m$) of M. persicae, were higher on Ferrari, Debla, Orange glory, and Jinju than on Purple, GreenAce, Orobell, and Thialf. On the bases of these results, we conclude that M. persicae preferred Ferrari, Jinju, Orange glory, and Debla among the 15 tested sweet pepper varieties. However, we could not show the preference of the aphid for Purple, Orobell, and Thialf.

• Analytical Science and Technology
• /
• v.26 no.3
• /
• pp.174-181
• /
• 2013

Pyrifluquinazon is classified with a quinazoline insecticide that regulates food intake by controling the feeding behavior acting on the endocrine or nervous system of pests such as aphids and white fly. To keep safety on pyrifluquinazon residues in agricultural commodities a simple, accurate and rapid analytical method was developed and validated using high performance liquid chromatograph (HPLC-UVD). The pyrifluquinazon residues acidified with 1% formic acid in samples were extracted with acetonitrile and partitioned with hexane subsequently to dichloromethane then purified with silica solid phase extraction (SPE) cartridge. The purified samples were detected using HPLC-UVD. The method was validated using apple and pear spiked with pyrifluquinazon at 0.02, 0.05 and 0.1 mg/kg and hulled rice, pepper, soybean at 0.05 and 0.1 mg/kg. Average recoveries were 70.5~107.9% with relative standard deviation less than 10%. The result of recoveries and overall coefficient of variation of a laboratory results in Gwangju regional FDA and Daejeon regional FDA was followed with Codex guideline (CODEX CAC/GL 40). This method is appropriated at pyrifluquinazon residues determination and will be used as official method of analysis.