• 한국전산유체공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.39-44
• /
• 2005

In HANARO, a multi-purpose research reactor of 30 MWth, the emergency water supply system consists essentially of an emergency water storage tank located in the level of about thirteen meter (13 m) above the reactor core, a three inch ('3\%') diameter water injection pipe line including injection valves from the tank to the reactor cooling inlet pipe and a test loop to do periodic system performance test. When the water level of the reactor pool comes down to the extremely low due to a loss of reactor pool water accident the emergency water stored in the tank should be fed to the core by the gravity force and at that time the design flow rate is eleven point four kilogram per second (11.4 kg/s). But it is impossible periodically to measure the injection flow rate under the emergency condition because the normal water level should be maintained during the reactor operation. This paper describes a flow network analysis to simulate the flow rate under the emergency condition. As results, it was confirmed through the analysis results that the calculated flow rate agrees with the design requirement under the emergency condition.

• Korean Parent-Child Health Journal
• /
• v.19 no.1
• /
• pp.17-24
• /
• 2016

Purpose: This study examined the level of students' anxiety depending on the injection type, education methods, and the students' characteristics. Methods: 209 first year nursing students were randomly assigned to each group by three factors -injection methods, video watching, and number of practice. Injection methods had two levels (IV and IM). Video watching also had also two levels (video watching and non-watching group). And the number of practice had 4 levels according to number of practice (2, 4, 6, and 8 times). The video watching group was watching 30 minutes video before manikin practice. After 5 to 15 minutes of manikin practice, the sufficiency of practice and the level of anxiety were measured. The data were analyzed by t-test and one way ANOVA. Results: The anxiety of the IV practice was higher than that of IM. The students who have experiences of working at hospital or the similar institution were lower in anxiety. The higher self-confident in sufficiency of practice lowered the students' anxiety. But watching video and the number of practices had no effects on the level of anxiety. Conclusion: To effectively lower the anxiety of nursing students in the nursing practice education, lecture methods and education tools are needed to develop.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.379-379
• /
• 2010

Recent technical advances in OLEDs (organic light emitting devices) requires more and more the improvement in low operation voltage, long lifetime, and high luminance efficiency. Inverted top emission OLEDs (ITOLED) appeared to overcome these problems. This evolved to operate better luminance efficiency from conventional OLEDs. First, it has large open area so to be brighter than conventional OLEDs. Also easy integration is possible with Si-based driving circuits for active matrix OLED. But, a proper buffer layer for carrier injection is needed in order to get a good performance. The buffer layer protects underlying organic materials against destructive particles during the electrode deposition and improves their charge transport efficiency by reducing the charge injection barrier. Hexaazatriphenylene-hexacarbonitrile (HAT-CN), a discoid organic molecule, has been used successfully in tandem OLEDs due to its high workfunction more than 6.1 eV. And it has the lowest unoccupied molecular orbital (LUMO) level near to Fermi level. So it plays like a strong electron acceptor. In this experiment, we measured energy level alignment and hole current density on inverted OLED structures for hole injection. The normal film structure of Al/NPB/ITO showed bad characteristics while the HAT-CN insertion between Al and NPB greatly improved hole current density. The behavior can be explained by charge generation at the HAT-CN/NPB interface and gap state formation at Al/HAT-CN interface, respectively. This result indicates that a proper organic buffer layer can be successfully utilized to enhance hole injection efficiency even with low work function Al anode.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.4
• /
• pp.84-91
• /
• 2006

In this study, the effect of EGR and fuel injection pressure on the characteristics of combustion and emission performance of the common-rail diesel engine is investigated using DME fuel as a smoke-free alternative fuel. Because the heating value and density of DME fuel are lower than those of diesel fuel, the injection duration of the DME engine is relatively longer than the injection duration of the diesel engine with the same injection pressure. However, the higher injection pressure can shorten the injection duration for the DME engine. Although the smoke level of the DME engine is much lower than that of the diesel engine, the NOx is at a level similar to that of the diesel engine. As a proposed solution for this, the EGR technique is empirically applied to the DME engine. In the experiments, the injection pressure was changed from 200bar to 400bar, and the EGR rate was limited under 40%. With the same injection timing and fuel amount, the experiment results indicated that the increase of injection pressure led to the increase of IMEP while decreasing HC and CO emissions. However, the NOx emission tends to increase as the injection pressure becomes higher. On the other hand, as the EGR rate was increased, NOx emission and A/F were reduced while the HC and CO emissions were increased. Because HC and CO emissions have the critical A/F point where the emissions of HC and CO are rapidly increased, it is proposed that the EGR rate must be limited under the critical EGR rate.

• Restorative Dentistry and Endodontics
• /
• v.25 no.3
• /
• pp.435-445
• /
• 2000

The purpose of this study was to compare the leakage of four different obturation techniques in conjunction with immediate apical barrier of ${\beta}$-tricalcium phosphate(TCP) in teeth with open apex. Eighty single-rooted human premolar teeth were prepared and sectioned horizontally, so maximum diameter in apex was 4mm. Apical defects that were similar to open apex, were created with #1/2 round bur and SF104R bur. The apical foramen were opened to a size 80 file extended 3mm beyond the apex. The teeth were placed into the oasis block soaked saline to simulate periapical tissue often associated with pulpless teeth and received apical barriers consisting of TCP followed by obturation using lateral condensation technique, vertical condensation technique, continuous wave technique and thermoplasticized gutta-percha injection technique. Two unobturated teeth served as positive and negative controls. Teeth were immersed in resorcinol-formaldehyde resin for S days at $4^{\circ}C$, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then sectioned horizontally at 1.5mm(level 1), 2.5mm(level 2) and 3.5mm(level 3) from the apex, and examined under a stereomicroscope at ${\times}40$ magnification. The photographs were taken at ${\times}40$ magnification of the filling in each level and scanned. The leakage length in tooth/resin interface was measured at each of the three levels. Each ratio of leakage was obtained by calculating the ratio of the leakage length of canal wall infiltrated with resin to the total length of the canal and was analyzed statistically(One-way ANOVA and Scheffe test). The result were as follows : 1. At the level 1, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there was statistically significant(p<0.05). 2. At the level 2, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), and the most leakage in the continuous wave technique group(group 3). There was statistically significant difference between the thermoplasticized gutta-percha injection technique group and the continuous wave technique group(p<0.05). 3. At the level 3, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there were no statistically significant differences between other groups(p>0.05). These results suggest that thermoplasticized gutta-percha injection technique which had 1mm apical gutta-percha matrix after the formation of TCP apical barrier, can demonstrate favorable apical sealing.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.19 no.3
• /
• pp.159-165
• /
• 2019

Background: Dental procedures commonly involve the injection of local anesthetic agents, which causes apprehension in patients. The objective of dental practice is to provide painless treatment to the patient. The purpose of this study was to evaluate the effect of Low Level Laser Therapy (LLLT) in reducing the pain due to local anesthetic injection. Materials and Methods: A prospective, split-mouth study was conducted on 25 patients. In Condition A, LLLT was administered followed by the administration of a standard local anesthetic agent. Patients' perception of pain with use of LLLT was assessed based on a Visual Analogue Scale (VAS). In Condition B, LLLT was directed to the mucosa but not activated, followed by the administration of local anesthesia. VAS was used to assess the pain level without the use of LLLT. Results: Comparison between Condition A and Condition B was done. A P value < 0.001 was considered significant, indicating a definite statistical difference between the two conditions. Conclusion: In our study, we observed that LLLT reduced pain during injection of local anesthesia. Further multi-centric studies with a larger sample size and various modifications in the study design are required.

• The Korean Journal of Pharmacology
• /
• v.15 no.1_2 s.25
• /
• pp.21-27
• /
• 1979

It is well known that picrotoxin, an amaroid substance of Anamirta cocculus, is a classic stimulant on the central nervous system accompanying convulsive activity, and it liberates catecholameine from the adrenal mdulla through its central action to increase blood sugar level. Schou reported that lithium and alcohol have the similar inhibitory property on the $Na^+,\;K^+$-ATPase activity, and recently, the therapeutic efficacies of lithium on the alcohol withdrawal syndrome and the chronic alcoholics have been studied. Many studies about the hypoglycemic effect of lithium and alcohol were reported but the interaction between those hypoglycemic action is little known. Therefore, in this paper, the hypoglycemic effect of lithium and ethanol on the hyperglycemia induced with picrotoxin, and the interaction of them in those hypoglycemic action were investigated with reference to the anticonvulsive action of them. The results were obtained as follows: 1. The convulsive dose (: $CD__{50}$) of picrotoxin in mice was slightly increased by the pretreatment of lithium or ethanol. 2. The blood sugar level was markedly increased by picrotoxin but the level was sugar level was significantly decreased by lithium, ethanol or both. 3. The hyperglycemic effect of picrotoxin was significantly potentiated by the lithium pretreatment, but the potentiation effect of lithium was markedly suppressed by the additional injection of ethanol after lithium injection and more markedly suppressed by the premedication of ethanol before lithium injection 4. The hyperglycemic effect of picrotoxin was markedly inhibited by the ethanol pretreatment, and the inhibitory effect of ethanol was significantly strenthened by the additional injection of lithium after ethanol injection, but on the contrary, the inhibitory effect was completely disappeared by the premedication of lithium before ethanol injection.

• The Korean Journal of Pain
• /
• v.20 no.1
• /
• pp.46-49
• /
• 2007

Background: Cervical epidural injection, performed via the interlaminar approach, represents a useful interventional pain management procedure indicated in patients with a cervical herniated disk. Due to thedecreased epidural space in the cervical region, cervical epidural injections may result in potentially serious complications, especially during a large volume injection. Methods: Thirty-four patients with neck pain due to a cervical herniated disk that were referred to the pain clinic for cervical epidural steroid injection were randomized into two groups. One group received a cervical epidural injection of 4 ml drug and the other group received 2 ml drug. The injected mixture included triamcinolon, ropivacaine and omnipaque. Spread levels of the drug after injection were estimated with the use of C-arm fluoroscopy. Results: Spread levels to the cephalad for patients in the two groups were $4.88{\pm}0.78segments$ and $4.53{\pm}0.49segments$, respectively. Spread levels to the caudad for patients in the two groups were $4.59{\pm}0.93segments$ and $4.47{\pm}0.51segments$, respectively. The results showed no significant difference in the spread level between the two groups. Conclusions: Use of a small volume of drug (2 ml) can provide a sufficient spread level of the injected drug that is desirable for patients with a cervical herniated disk.

• Clinical and Experimental Reproductive Medicine
• /
• v.21 no.3
• /
• pp.305-314
• /
• 1994

19-norandrostenedione(19-NORA) is known as an intermediate in the metabolic pathway from androstenedione to estrone. Administration of esterified 19-nortestosterone, anabolic steroid, reduces serum gonadotropin and testosterone concentration, and results in reversible azoospermia in men. 19-NORA have been isolated from testis, but its function in testis is not clear yet. Therefore, this study was designed to determine the effect of 19-NORA on steroidogenesis and on spermatogenesis. 19-NORA was administrated by single intratesticular injection to adult male rats weighing 350-400 g in dose of 1 mg/50${\mu}l$. The serum and testis were collected on 1, 3, 7, 12, 48 hr after injection. The histological differences in testis were observed by routine paraffin method. The concentrations of testosterone and estradiol in serum and in left testis were determined by the conventional radioimmunoassays. One hour after 19-NORA treatment, serum concentrations of testosterone and estradiol increased significantly, compared to those of pre-treated(0 hr) group, and reduced gradually to the control level on 7 hour after injection. The concentration of testosterone in left testis increased slightly 1 hour after injection, and estradiol level increased significantly(p<0.05). Also, testosterone and estradiol level of control group revealed no difference with pre-treated (0 hr) group. Gonad index, structure of seminiferous tubules, and the number of step 7 th spermatid were simillar to control group. The present study suggests that the elevation of testosterone level results from increment of estradiol followed by the rapid metabolism of 19-NORA at 7 hour after injection, and then testosterone concentration may be recovered to control level by feedback mechanism of hypothalamus-hypothysis-testis axis.

• The Korean Journal of Pain
• /
• v.23 no.2
• /
• pp.131-136
• /
• 2010

Background: We prospectively evaluated the incidence and possible factors causing intramuscular injection during lumbar sympathetic ganglion block and compared the multiple needle technique to the single technique to obtain a profound and complete block effect. Methods: Among 83 patients, 58 patients (group A, n = 27, multiple needle technique and group B, n = 31, single needle technique) were reevaluated for the changes of skin temperature (Ts) and mean segment of longitudinal contrast spread. After injecting the contrast agent, the incidence of psoas muscle injection and the change of Ts was compared between two groups. Results: The incidence of psoas muscle injection was 21.3% (46/216) and it was associated with the level of injection (L2) significantly (${\chi}_2$ = 14.773, P = 0.001). $DT^{post}$ (postblock temperature difference between ipsilateral and contralateral great toe, $4.6{\pm}2.8^{\circ}C$, $1.8{\pm}1.6^{\circ}C$, P < 0.001 for group A and B) and $DT^{net}$ ($DT^{post}$ - $DT^{pre}$, $3.9{\pm}2.7^{\circ}C$, $1.5{\pm}1.5^{\circ}C$, P < 0.001 for group A and B) was significantly higher in group A. The mean segment of longitudinal contrast spread was $8.1{\pm}0.9$ for group A and $3.2{\pm}1.6$ for group B (P < 0.001). Conclusions: The LSGB at the L2 level showed the lowest incidence of psoas muscle injection of contrast. Multiple needle approach showed more significant increase of $DT^{net}$ and $DT^{post}$.