• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.05a
• /
• pp.88-92
• /
• 2009

Total pressure recovery ratio in intake is crucial factor to the operational characteristics of supersonic propulsion system because it does not compress inlet air mechanically by compressor, but does compress inlet air by ram compression. As the result of that the dynamic characteristic analysis of engine was performed before the controller was designed, it could be ascertained when the AoA of flight vehicle increases, the buzz margin decreases so that the shock wave produced outside intake in the specified area according to flight operation's characteristics. Therefore the PID control algorithm was designed to be controlled buzz margin that the characteristic of shock wave could meet the requirement of performance in intake. The PID controller was designed that the buzz margin value is being positive number using the control variables; fuel flow and nozzle throat area.

• Women's Health Nursing
• /
• v.10 no.4
• /
• pp.351-359
• /
• 2004

Purpose: A descriptive study was conducted to examine the levels of distress, state anxiety, and physiologic responses in postoperative patients under patient controlled analgesia (PCA), and to determine correlations among the variables. Method: The study sample included women who underwent an elective hysterectomy procedure or other gynecologic surgeries(N=100). Subjective distress was assessed by visual analog scales around 8 hours postoperatively. Trained nurses collected objective distress data through observation of subject's behavior and vital signs. Data were analyzed with frequencies, percentages, means, Pearson correlation coefficients, ANOVA, and the Scheffe post test using SPSS/PC 11.0. Result: Subjective distress, objective distress, and state anxiety scores were relatively low, except pain scores(5.31 out of 10.0) among sub-scales of subjective distress. Women who had a total abdominal hysterectomy showed significantly higher levels of both subjective distress and state anxiety than those after a minor gynecologic surgery. In relationships among variables, subjective distress correlated positively with postoperative state anxiety, but not with the amount of analgesic medication, verified by further analysis on sub-scales of subjective and objective distress. The higher the levels of state anxiety, the higher the levels of tension, dyspnea, facial change, and systolic blood pressure observed. Conclusion: Regardless of effective pain management, most postoperatively experienced distress in gynecological patients was derived from surgery associated anxiety and pain. Specific psychological strategies should be established as well for those with high levels of state anxiety to facilitate prompt recovery.

• Korean Journal of Food Science and Technology
• /
• v.28 no.2
• /
• pp.378-383
• /
• 1996

Dietary fibers (DF) have been used as functional food components due to the various health promoting activities. Dietary fibers have been separated from the peels of Korean tangerine by employing ultrafiltration (UF) membranes. Optimum conditions in a batch type ultrafiltration unit using YM100 (molecular weight cut-off, MWCO=100,000), YM 10 (MWCO=10,000) and YM1 (MWCO=1,000) membranes were : transmembrane pressure 7.5 psi, temperature of the peel extracts $35^{\circ}C$, and pH of the peel extract 3.0, respectively. The flux in YM 10 membrane unit was higher than that in YM 10 or YM 1 membrane unit. However, YM 100 membrane was superior to YM 10 or YM 1 membrane with respect to the recovery of the retentate and the contents of DF The contents of DF in the tangerine peel extract, in the 170 mesh retentate, and in the YM 100 retentate were shown to be 33.4%, 18.5% and 8.4% based on dry matter, respectively. Most dietary fibers were recovered at the separation stages of 170 mesh and YM 100.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.634-643
• /
• 2004

In this paper are presented a concept of a new supersonic air inlet, which is designated a Multi-Row Disk (MRD) inlet, aiming at performance improvement under off-design conditions, and results of wind tunnel tests examined performance characteristics of the MRD inlet. The MRD inlet is frequently called ‘a skeleton inlet’ because of its appearance. The performance of a conventional axisymmetric inlet with a solid center body (spike) deteriorates under off-design Mach number conditions. It is due to the fact that total pressure recovery (TPR) governed by the throat area of inlet and mass capture ratio (MCR) governed by an incidence position of an oblique shock from the spike tip into the cowl can not be controlled independently in such air inlet. The MRD inlet has the spike that is composed of a tip cone and several disks arranged downstream of it, based on the experimental fact that several deep cavities on a conical surface have little negative effect on the boundary layer growth. The overall spike length of the MRD inlet is adjustable to the given flight speed by changing space between disks so that a spillage flow can be controlled independently from controlling the throat area. It could be made clear from the result of wind tunnel tests that the MRD inlet improves TPR by 10% compared with a conventional inlet with a solid spike under off-design conditions.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.47 no.3
• /
• pp.195-203
• /
• 2019

Since the hypersonic intake is directly related to the overall performance of the engine, it is essential to analyze performance characteristics under various off-design conditions. In this paper, Busemann intake and conical intake with external compression were designed, and numerical simulations were performed at on/off-design conditions. Based on the results, the overall performance characteristics of two types of intake were analyzed in various Mach numbers and angle of attacks. The results showed that performance degradation of Busemann intake with truncation angle of 2 degrees was minimal. Also, the performance of Busemann intake was higher than external compression intake at various Mach numbers, however, the starting characteristics were significantly reduced with an angle of attack.

• Korean Journal of Pharmacognosy
• /
• v.53 no.4
• /
• pp.213-225
• /
• 2022

Schisandra chinensis is widely known to regulate fatigue recovery, lowering blood pressure, and contains several bioactive compounds such as schizadran. In this study, we obtained basic data for the development of health food by measuring the schizandrin content, antioxidant activity, anti-inflammatory, antibacterial activity, and enzyme activity of the hot water extract (SCW) and 40% ethanol extract (SCE) of S. chinensis grown in Sunchang-gun, Korea. Schizandrin content was measured as 7.87 ± 0.01 mg/g for SCW and 10.38 ± 0.05 mg/g for SCE. SCE had higher DPPH and ABTS radical scavenging activity than SCW, and the total polyphenol and flavonoid contents were also higher. Both SCW and SCE (500 ㎍/mL) exhibited more than 55% protective effects against oxidative stress in HepG2 cell lines. Anti-inflammatory efficacy was assessed using RAW 264.7 and Caco-2 cells and both SCW and SCE do not have cytotoxic effects. Anti-inflammatory results showed concentration-dependent NO activity and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) inhibition. The antibacterial activity increased with increasing dose concentrations of SCW and SCE, and the MIC was 25 mg/mL for L. monocytogenes, S. typhimurium, and 75 mg/mL for H. pylori. In addition, amylase and protease enzyme activity was observed in both SCW and SCE.

• Nuclear Engineering and Technology
• /
• v.27 no.4
• /
• pp.470-482
• /
• 1995

The Ulchin 3&4, which are 2825 MWt PWRs, adopted Safety Depressurization System (SDS) to mitigate the beyond design basis event of Total Less of Feedwater(TLOFW). In this study the results and methodology of the analyses for the determination of SDS bleed capacity are discussed. The SDS design bleed capacity has been determined from the CEFLASH-4AS/REM simulation according to the following design criteria : 1) Each SDS flow path, in conjunction with one of two High Pressure Safety Injection (HPSI) pumps, is designed to have a sufficient capacity to prevent core uncovery if one SDS path is opened simultaneously with the opening of the Pressurizer Safety Valves (PSVs). 2) Both SDS bleed paths are designed to have sufficient total capacity with both HPSI pumps operating to prevent core uncovery if the Feed and Bleed (F&B) initiation is delayed up to thirty minutes from the time of the PSVs lift. To verify the results of CEFLASH-4AS/REM simulation a comparative analysis kas also been per-formed by more sophisticated computer code, RELAP5/MOD3. The TLOFW event without operator recovery and TLOFW event with F&B are analyzed. The predictions by the CEFLASH-4AS/REM of the transient too phase system behavior are in good qualitative and quantitative agreement with those by the RELAP5/MOD3 simulation. Both of the results of analyses by CEFLASH-4AS/REM and RELAP5/MOD3 have demonstrated that decay heat removal and core inventory make-up can be successfully accomplished by F&B operation during now event for the Ulchin 3&4.

• Journal of Veterinary Clinics
• /
• v.28 no.5
• /
• pp.479-485
• /
• 2011

The cardiopulmonary responses during total intravenous anesthesia (TIVA) between remifentanil/propofol infusion and remifentanil/ketamine infusion in dogs were compared. Fourteen healthy adult beagle dogs were premedicated with acepromazine (0.1 mg/kg, SC) and medetomidine (20 ${\mu}g$/kg, IV), and anesthetized for 3 hr with remifentanil (0.5 ${\mu}g$/kg/min)/propofol (loading dose: 1 mg/kg, CRI: 0.3 mg/kg/min) CRI (group 'P') or remifentanil/ ketamine (loading dose : 5 mg/kg, CRI: 0.1 mg/kg/min) CRI (group 'K'), respectively. Hemodynamics, blood gas analysis and behavioral changes during recovery were measured. The level of anesthesia was determined by toe-web clamping test. The level of surgical anesthesia was maintained throughout the experiment in both groups. Systolic arterial pressure, mean arterial pressure, $PaO_2$ and $SpO_2$ in group 'K' were significantly higher than in group 'P', and were maintained near the normal ranges. In addition, $PaO_2$ in group 'K' was significantly lower than in group 'P'. However, diastolic arterial pressure, heart rate and respiratory rate were not significantly differed. Mean extubation time from the end of infusion was significantly reduced in group 'K', but mean sitting time was significantly reduced in group 'P'. Mean head-up time and mean walking time were not significantly differed. In group 'K', brief muscle rigidity, head waving and licking during recovery were observed. In conclusion, infusion rate of ketamine (0.1 mg/ kg/min) with remifentanil (0.5 ${\mu}g$/kg/min) is an appropriate for obtaining the surgical plane of anesthesia. These results showed that group 'K' had better cardiopulmonary function than group 'P'. That is, remifentanil/ketamine CRI is better TIVA protocol than remifentanil/propofol CRI for 3 hr surgery.

• The Korean Journal of Pesticide Science
• /
• v.16 no.1
• /
• pp.11-20
• /
• 2012

As increasing the use of pesticides both in number and amount to boost crop production, consumer concerns over food quality and safety with respect to residual pesticides are also continuously increasing. However, there is still lacking of information that can effectively help to remove residual pesticides in foods. In recent years, contaminant removal by gas (or) glow discharge plasma (GDP) attracts great interests on environmental scientists because of its high removal efficiency and environmental compatibility. It was shown to be effective for the removal of some organophosphorus pesticides, phenols, benzoic acid, dyes, and nitrobenzene on solid substrate or in aqueous solution. This work mainly focuses on the removal of wide range of residual pesticides from fresh fruits and vegetables. As for preliminary study, the experiments were carried out to investigate whether GDP can be used as an effective tool for degrading target pesticides or not. With this objective, 60 selected pesticides drop wised onto glass slides were exposed to two types of GDP, dielectric barrier discharge plasma (DBDP) and low pressure discharge plasma (LPDP), for 5 min. Then, they were washed with 2 mL MeCN which were collected and used for determination of remaining concentration of pesticides using LC-MS/MS. Among selected pesticides, degradation of 18 pesticides (endosulfan-total was counted as one pesticide) by GDP could not be examined because control treatments, which were left in ambient environment, of those pesticides recovered less than 70% or even did not recover. However, majority of tested pesticides (42) were degraded by both types of GDP with satisfactory recovery (>80%) of control sample. Pesticides degradation ranged from 66.88% to 100% were achieved by both types of plasma except clothianidin which degradation in LPDP was 26.9%. The results clearly indicate that both types of gas discharge plasma are promising tools for degrading wide range of pesticides on glass substrate.

• Journal of Chest Surgery
• /
• v.29 no.1
• /
• pp.14-23
• /
• 1996

Circulatory arrest under deep hypothermia is an important auxiliary means for cardiac surgery, especially useful in pediatric patients. However, its clinical safety, particularly with regard to the neurologic outcome after long duration of circulatory arrest, is still not established. This study is a review of the eight years'clinical experience of hypothermic circulatory arrest at the Seoul national University Children's Hospital. During an eight-year period from January 1986 through December 1993, a total of 589 consecutive cardiac operations were done using circulatory arrest under deep hypothermia. Among them, 434 consecutive patients, in whom the duration of arrest was 20 minutes or more, are the subject of this study. The duration of arrest ranged from 20 minutes to 82 minutes (mean = 38.7 minutes) under rectal temperature in the range from 12.5$^{\circ}C$ to 25.8$^{\circ}C$. Early neurologic abnormalities occurred in 47 patients : seizure attacks in 28 patients, motor paralyses with or w thout seizure in 12, blindness in 2, and no recovery of consciousness in 5 patients. The rate of incidence of early neurologic abnormalities was calculated at 15.7%. 25 patients showed late neuropsychologic sequelae, such as motor paralysis (9 patients), recurrent seizures (6), developmental delay (8), and definitely low intelligence (2). The rate of incidence of late neurologic sequelae was 8.5%, By statistical analysis, the following factors were identified as the risk factors for post-arrest neurologic abnormalities ; 1) long duration of circulatory arrest, 2) lower-than-ideal body weight, 3) preexisting neurological abnormalities, 4) associated non-cardiovascular congenital anouialies, and 5) low blood pressure during the early post-arrest period. It is concluded that circulatory arrest under deep hypothermia is a relatively safe means for pediatric cardiac surgery with acceptable risk. However, to warrant maximal safety, it is desirable to limit the duration of arrest to less th n 40 minutes. In addition, it is our contention that the early post-arrest period is a very critical period during which maintenance of adequate perfusion pressure in important for the neurologic outcome.