• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.239-240
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• 2008

As semiconductor devices are scaled down for better performance and more functionality, the Cu-based interconnects suffer from the increase of the resistivity of the Cu wires. The resistivity increase, which is attributed to the electron scattering from grain boundaries and interfaces, needs to be addressed in order to further scale down semiconductor devices [1]. The increase in the resistivity of the interconnect can be alleviated by increasing the grain size of electroplating (EP)-Cu or by modifying the Cu surface [1]. Another possible solution is to maximize the portion of the EP-Cu volume in the vias or damascene structures with the conformal diffusion barrier and seed layer by optimizing their deposition processes during Cu interconnect fabrication, which are currently ionized physical vapor deposition (IPVD)-based Ta/TaN bilayer and IPVD-Cu, respectively. The use of in-situ etching, during IPVD of the barrier or the seed layer, has been effective in enlarging the trench volume where the Cu is filled, resulting in improved reliability and performance of the Cu-based interconnect. However, the application of IPVD technology is expected to be limited eventually because of poor sidewall step coverage and the narrow top part of the damascene structures. Recently, Ru has been suggested as a diffusion barrier that is compatible with the direct plating of Cu [2-3]. A single-layer diffusion barrier for the direct plating of Cu is desirable to optimize the resistance of the Cu interconnects because it eliminates the Cu-seed layer. However, previous studies have shown that the Ru by itself is not a suitable diffusion barrier for Cu metallization [4-6]. Thus, the diffusion barrier performance of the Ru film should be improved in order for it to be successfully incorporated as a seed layer/barrier layer for the direct plating of Cu. The improvement of its barrier performance, by modifying the Ru microstructure from columnar to amorphous (by incorporating the N into Ru during PVD), has been previously reported [7]. Another approach for improving the barrier performance of the Ru film is to use Ru as a just seed layer and combine it with superior materials to function as a diffusion barrier against the Cu. A RulTaN bilayer prepared by PVD has recently been suggested as a seed layer/diffusion barrier for Cu. This bilayer was stable between the Cu and Si after annealing at $700^{\circ}C$ for I min [8]. Although these reports dealt with the possible applications of Ru for Cu metallization, cases where the Ru film was prepared by atomic layer deposition (ALD) have not been identified. These are important because of ALD's excellent conformality. In this study, a bilayer diffusion barrier of Ru/TaCN prepared by ALD was investigated. As the addition of the third element into the transition metal nitride disrupts the crystal lattice and leads to the formation of a stable ternary amorphous material, as indicated by Nicolet [9], ALD-TaCN is expected to improve the diffusion barrier performance of the ALD-Ru against Cu. Ru was deposited by a sequential supply of bis(ethylcyclopentadienyl)ruthenium [Ru$(EtCp)_2$] and $NH_3$plasma and TaCN by a sequential supply of $(NEt_2)_3Ta=Nbu^t$ (tert-butylimido-trisdiethylamido-tantalum, TBTDET) and $H_2$ plasma. Sheet resistance measurements, X-ray diffractometry (XRD), and Auger electron spectroscopy (AES) analysis showed that the bilayer diffusion barriers of ALD-Ru (12 nm)/ALD-TaCN (2 nm) and ALD-Ru (4nm)/ALD-TaCN (2 nm) prevented the Cu diffusion up to annealing temperatures of 600 and $550^{\circ}C$ for 30 min, respectively. This is found to be due to the excellent diffusion barrier performance of the ALD-TaCN film against the Cu, due to it having an amorphous structure. A 5-nm-thick ALD-TaCN film was even stable up to annealing at $650^{\circ}C$ between Cu and Si. Transmission electron microscopy (TEM) investigation combined with energy dispersive spectroscopy (EDS) analysis revealed that the ALD-Ru/ALD-TaCN diffusion barrier failed by the Cu diffusion through the bilayer into the Si substrate. This is due to the ALD-TaCN interlayer preventing the interfacial reaction between the Ru and Si.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.115-123
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• 2005

Historical changes of population abundances of European red mite (ERM), Panonychus ulmi (Koch), and two-spotted spider mite (TSSM), Tetranychus urticae (Koch) (Acari: Tetranychidae), were described in selected apple orchards in the National Horticultural Research Institute (NHRI, Suwon, Korea), based on research reports of the NHRI from 1958 to 1998. ERM was an abundant species up to 1970, and TSSM became a dominant species after 1980. The change occurred around mid 1970. Three hypotheses were made to explain the change: TSSM competitively replaces ERM, ground cover weeds are a major influencing factor on movement of TSSM (TSSM movement into trees is accelerated by destroying weeds), and ERM and TSSM populations are regulated by natural enemy complexes when the orchard system is not disrupted. And long-term results of the interaction between two species were projected according to the combination of different orchard management strategies: pesticide sprays (non-selective toxic pesticide spray : heavy pesticide pressure (HPP), and selective soft pesticide spray = low pesticide pressure (LPP)) and weed control methods (grass planting, and clean culture system with herbicides). In the HPP and grass planting system, ERMs are abundant because ERM can avoid competition with TSSM as movement of TSSM to trees are restricted, and natural enemy complexes are destroyed by toxic pesticides. In the HPP and clean culture system, TSSMs are abundant because TSSM moves to trees from early season and competitively replaces ERM. In the LPP and grass planting system, ERMs are abundant because movement of TSSM to trees is reduced, but they do not build up a high population density since their densities are regulated by natural enemy complexes. In the LPP and clean culture system, TSSM moves to trees and competes with ERM, but the competition pressure is reduced because population densities of mites are regulated in a lower level by natural enemy complexes. So, ERM can occurs in late season. Thus, two species can coexist temporarily with more ERM in early season and more TSSM in late season. TSSM abundant phenomenon presented in this study can be partially explained as a result of long-term interaction between ERM and TSSM under the HPP and clean culture system.

• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.222-230
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• 2018

This study aimed to determine effects of light-emitting diodes on plant growth, leaf morphology and cell elongation of two cultivars ('World-star' and 'Sushiro') of Spinacia oleracea. Plants were grown in a NFT system for 25 days after transplanting (DAT) under the LEDs [White (W), Red and Blue (RB, ratio 2:1), Blue (B), Red (R) LED] under the same light intensity and photoperiod ($130{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 12 hours). The 'World-star' variety was significantly higher in shoot fresh and dry weights, leaf number, and leaf area than the 'Sushiro' variety. For the 'World-star' variety, the two treatments of mixed light (RB) and red light (R) showed a 35% higher shoot dry weight than that of blue light (B) and white light (W) at 25 DAT. In the 'Sushiro' variety, mixed light (RB) treatment, which had the highest shoot fresh and dry weights, showed 40% higher than the white light (W) treatment, which had the lowest shoot fresh and dry weights. Both varieties showed leaf epinasty symptom at 21 DAT only in both mixed light (RB) and red light (R), and red light (R) treatment showed significantly higher symptom than mixed light (RB), indicating the leaf epinasty is associated with red light. Microscopic observations of the cell size in the leaf center and edge parts showed that the cell density of leaf edge under the red light (R) was lower than that in leaf center, supporting previous reports that suggest an association of the cell size difference between the leaf center and edge with the leaf epinasty occurrence. Since the blue light (B) plays a role in alleviating the epinasty symptom caused by the red light (R), it seems necessary to identify the appropriate mixing ratio of the two light sources. In addition, the World-star variety seems to be more suitable for the cultivation of plant factory using LED light sources.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.1
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• pp.55-65
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• 1999

There have been many reports to date regarding the role of GnRH as a local regulatory factor of ovarian function as studies of human and rat ovaries revealed GnRH and its receptor. In recent studies it has been shown that GnRH directly causes apoptosis in the granulosa cells of the rat ovary, and such results leads to the suggestion that the use of GnRH agonist for more stable long term ovarian hyperstimulation in human IVF-ET programs causes granulosa cell apoptosis which may lead to follicular atresia. Therefore this study attempts to determine if granulosa-luteal cell apoptosis occurs in patients during IVF-ET programs in which GnRH agonist is employed for ovarian hyperstimulation. The quality of oocyte-cumulus complexes obtained during ovum pickup procedures were assessed morphologically and then the fertilization rate and developmental rate was determined. Apoptotic cells among the granulosa-luteal cells obtained during the same procedure were observed after staining with Hematoxylin-eosin. The fragmentation degree of DNA extracted from granulosa-luteal cells was determined and comparatively analyzed. There was no difference in the average age of the patients, the number of oocytes retrieved, and fertilization and developmental rates between the FSH/hMG group and GnRH-long group. There was also no difference in the apoptosis rate and pyknosis rate in the granulosa-luteal cells between the two groups. However, when the oocyte-cumulus complexes were morphoogically divided into the healthy group and atretic group without regard for the method of hyperstimulation, the results showed that the number of oocytes obtained averaged $11.09{\pm}8.75\;and\;10.33{\pm}4.53$ per cycle, respectively, showing no significant difference, but the fertilization rate (77.05%, 56.99%, respectively, p<0.01) and developmental rate (65.96%, 41.51%, respectively, p<0.01) was significantly increased in the healthy group when compared to the atretic group. The degree of apoptosis in the granulosa-luteal cells showed that in the healthy group it was 2.25% which was not significantly different from the atretic group (2.77%), but the pyknosis rate in the atretic group (27.81%) was significantly higher compared to the healthy group (11.35%, p<0.01). The quantity of DNA fragmentation in the FSH/hMG group was 32.22%, while in the GnRH-long group it was 34.27%, showing no significant difference. On the other hand the degree of DNA fragmentation was 39.05% and 11.83% in the healthy group and atretic group, respectively, showing significantly higher increase in the atretic group (p<0.01). The above results suggest that death of granulosa-luteal cells according to the state of the oocyte-cumulus complex is more related to pyknosis rather than apoptosis. Also, the GnRH agonist used in ovarian hyperstimulation does not seem to directly affect the apoptosis of retrieved oocytes and granulosa-luteal cells, and which is thought to be due to the suppression of the apoptogenic effect of GnRH agonist as a result of the high doses of FSH administered.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.233-243
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• 2009

We have investigated the infrared spectra for CO adsorbed on silica supported nickel(Ni-Si$O_2$), silica supported copper(Cu-Si$O_2$), silica supported nickel-copper alloys(Ni/Cu-Si$O_2$) of several compositions with varying CO pressures(0.2 $torr{\sim}$50 torr) at room temperature and on pumping to vacumn at room temperature within the frequency range of 1500 $cm^{-1}{\sim}2500\;cm^{-1}$. Four bands(2059.6 $cm^{-1},\;{\sim}$2036.5 $cm^{-1},\;{\sim}$ 1868.7 $cm^{-1},\;{\sim}$ 1697.1 $cm^{-1}$) were observed for Ni-Si$O_2$, two bands($\sim$2115.5 $cm^{-1},\;{\sim}$1743.0 $cm^{-1}$) were observed for Cu-Si$O_2$ and five bands(${\sim}2123.2\;cm^{-1}$, 2059.6 $cm^{-1},\;{\sim}$2036.4 $cm^{-1},\;{\sim}$1899.5 $cm^{-1},\;{\sim}$1697.1 $cm^{-1}$) were observed for Ni/Cu-Si$O_2$. These absorption bands correspond with those of the previous reports approximately. The bands below 1800 $cm^{-1}$ were only observed with Ni metal or Ni/Cu alloy crystal plane containing step at room temperature and the ${\sim}1697.1\;cm^{-1}$ bands observed with Ni-Si$O_2$ and Ni/Cu-Si$O_2$ may be ascribed to CO molecule adsorbed on the adsorption sites near step. The bands below 2000 $cm^{-1}$ were rarely observed with Cu metal crystal plane at room temperature and the 1743.0 $cm^{-1}$ bands may be ascribed to CO molecule adsorbed on the adsorption sites near step. The band shifts of adsorbed CO with varing Cu contents from 0 to 0.5 mole fraction at the same CO pressure or at the same pumping time to vacumn were below 21 $cm^{-1}$. and comparatively small than those with other ⅠB metal addition. It may means ligand effect of Cu d electron is small.

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.913-922
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• 1995

Background: When we define the pressure of pulmonary vasculature in which a recruitment of blood flow occurs as $P_I$ and the proportion of change in pulmonary artery to that in cardiac output as IR and then we compare PI and IR with pulmonary vascular resistance, we would find some problems in pulmonary vascular resistance. In other words, it is the theory that, IR should be increased mainly in pulmonary embolism in which decreases the cross sectional area of pulmonary vasculature. But there are many contradictory reports resulted from various researches and the fact is known widely that any difference exists between PVR and PI, IR. For this reason, the purpose of this study is to observe how PI and IR change at the time of the outbreak and during treatment of the pulmonary embolism, and to find out the meaning of these new indicators and the difference from the pulmonary vascular resistance used generally when we subdivide the pulmonary vascular resistance into PI and IR. Method: After making AV fistula in experimental dog, we controlled cardiac output at the intervals of 15 minute in case of three kinds(all AV fistula are obstructed, only one of fistula is open and all of fistula is open), and after evoking massive pulmonary embolism with radioactive autologous blood clots, we measured the mean pulmonary artery pressure, and calculated PI and IR. We observed the pattern of change in PI and IR, without giving the control group any specific treatment and with injecting intravenously rtPA in the Group 1 and Group 2 at the dose of 1mg per kg, for 15 minutes fot the former and 3 hours for the latter. Result: 1) Pulmonary vascular resistance showed a change similar to that of pulmonary artery pressure and in all three group, PVR increased significantly, but group 1 and group 2 showed tendency that PVR keeps on decreasing after treatment, and the rate of decrease in group 1 is more rapid than group 2 significantly. 2) Both intersection(PI) and degree(IR) are proved statistically significant, in view of the straight line relationship between cardiac output and pulmonary artery pressure, calculated by minimal regression method. 3) PI changed similarly to pulmonary vascular resistance, while in the IR which is theoretically more similar to PVR, there was no significant difference or change after rtPA infusion. Conclusion: In the pulmonary embolism, Both change in IR which means real resistance of pulmonary vasculature and PI which was developed due to secondary vasoconstriction by pulmonary embolism are reflected same time.

• Tuberculosis and Respiratory Diseases
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• v.39 no.6
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• pp.511-516
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• 1992

Background: It is well known that cigarette smoking is the risk factor of lung cancer, chronic obstructive pulmonary disease and ischemic heart disease. But there are few reports about the immediate effect of cigarette smoking on the cardiopulmonary functions. The serum level of carbon monoxide increases during cigarette smoking. It is known that carbon monoxide increases respration rate, heart rate and cardiac output, with decrease in maximal oxygen consumption. So we have studied to determine the immediate effects of cigarette smoking on the cardiopulmonary function during exercise. Method: Thirteen healthy smoking male subjects were included in this study. Each subject was undertaken pulmonary function test and incremental exercise test on two separate days, one without smoking (control) and the other after smoking three cigarettes per hour for five hours. The order of the two tests was randomized. Results: 1) The mean age of the subjects was $25{\pm}4.9$ year-old and the mean smoking history was $6{\pm}5$ pack years. 2) The mean blood level of carbon monoxide on the smoking day was higher than that on the nonsmoking day ($5.97{\pm}1.34%$ vs. $1.45{\pm}0.83%$; p<0.01). 3) The mean maximal oxygen consumption on the smoking day was lower than that on the nonsmoking day ($2.09{\pm}0.32$ L/min vs. $2.39{\pm}0.32$ L/min; p<0.05). 4) The mean anaerobic threshold on the smoking day was lower than that on the nonsmoking day ($1.33{\pm}0.24$ L/min vs. $1.53{\pm}0.20$ L/min; p<0.05). 5) The mean heart rate at rest on the smoking day was higher than that on nonsmoking day ($84.38{\pm}11.06$ beats/min vs. $75.46{\pm}5.83$ beats/min; p<0.05). But the means of maximal heart rate on both days were not different. 6) The pulmonary function tests were similar on both days. Conclusion: There was no change in pulmonary function test, but the maximal oxygen consumption and anaerobic threshold were decreased on the smoking day. So it was concluded that cigarette smoking impaired the cardiovascular functions immediately during exercise.

• Tuberculosis and Respiratory Diseases
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• v.61 no.5
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• pp.463-472
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• 2006

Background: Since video-assisted thoracoscopic surgery (VATS) was introduced as a new treatment modality for empyema thoracis, numerous reports have suggested that VATS is a more effective treatment method than the traditional methods that mainly use antibiotics and drainage apparatus. However, no confirmative evidence of the superiority of VATS over the traditional method has been provided yet. Methods: We attempted to evaluate the efficacy of VATS for the treatment of empyema thoracis by reviewing past medical records and simple chest films. First, we divided the patients into two groups based on the treatment method: group A of 15 patients who were treated with the traditional method between January 2001 and December 2003, and group B of 9 patients who were treated with VATS between December 2003 and August 2006. The final outcomes used in this study were the number of days of hospital stay, chest tube duration, leukocytosis duration, febrile duration, and intravenous antibiotics usage duration. In addition, radiological improvements were compared. Results: The mean age(${\pm}$standard deviation) of 11 men and 4 women in group A was $58.2{\pm}15.7$ years, and of 9 men and 2 women in group B was $51.6{\pm}9.5$ years. Group B had a significantly shorter hospital stay ($16.6{\pm}7.4$ vs. $33.7{\pm}22.6$ days; p=0.014), shorter chest tube duration ($10.5{\pm}5.7$ vs. $19.5{\pm}14.4$ days; p=0.039), shorter leukocytosis duration ($6.7{\pm}6.5$ vs. $18.8{\pm}13.2$ days; p=0.008), shorter febrile duration ($0.8{\pm}1.8$ vs. $9.4{\pm}9.2$ days; p=0.004), and shorter duration of intravenous antibiotics usage ($14.9{\pm}6.4$ vs. $25.4{\pm}13.9$ days; p=0.018). However, radiological improvements did not show any statistical differences. Conclusion: Early application of VATS for empyema thoracis treatment reduced hospital stay, thoracostomy tube duration, leukocytosis duration, febrile duration, and antibiotics usage duration in comparison with the traditional methods. The early performing of VATS might be an effective treatment modality for empyema thoracis.

• Tuberculosis and Respiratory Diseases
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• v.61 no.5
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• pp.456-462
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• 2006

Background: Differential diagnosis is very important in patients with pleural effusions. A few studies on the etiologies of massive pleural effusions have been reported, but these were conducted in different decades and locations. In the present study, the etiologic spectrum of massive pleural effusions in Korea, were evaluated through an investigation at one university hospital. Methods: Retrospective chart reviews were performed in patients having undergone thoracentesis between July 2002 and July 2005. Pleural effusions were deemed to be massive if they occurred in two thirds or more of one hemithorax. The etiologies of massive pleural effusions, pleural fluid findings, serum laboratory findings, and sputum and pleural fluid cytologies were compared. Results: Of 298 pleural effusions cases, 41 (13.8%) had massive pleural effusions. The most frequent causes of massive pleural effusions were malignancy (19; 46.3%) followed by tuberculosis (15; 36.6%), parapneumonic effusion (4; 9.8%) and transudate (3; 7.3%). Compared with massive benign effusions, patients with massive malignant pleural effusions were more likely to have lower adenosine deaminase (ADA) activity, a higher amylase level and higher RBC count in their pleural fluids. Also, compared with non-tuberculosis effusions, patients with massive tuberculous pleural effusions were more likely to have lower RBC and neutrophil counts, but a higher lymphocyte count, adenosine deaminase (ADA) activity and protein level. Conclusion: The most common etiologies of massive pleural effusions in Korea are malignancy and tuberculosis. A high ADA content favors a tuberculous condition, while bloody effusions with a relatively lower ADA content. favors malignancy. The proportion of tuberculosis in massive pleural effusions was higher than in previous reports.

• Journal of The Korean Association For Science Education
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• v.35 no.1
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• pp.159-167
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• 2015

RI-Biomics is a promising radiation convergence technology that combines radiation with bio science as new growth power technology. Many developed countries are focusing active support and constant exertion to dominate the RI-Biomics market in advance. In order to achieve global leadership in the RI-Biomics field, we need more highly advanced technologies and professional manpower. In fact, we have less manpower compared to technology we currently hold. In this study, we established a basic infrastructure to train professional manpower in the RI-Biomics field by developing/operating optimum training program through expert interviews and survey. The developed program has four organized sections to understand overall procedure of RI-Biomics. To evaluate our training program, we performed test operations with eight students who have a major related to RI-Biomics for three weeks in KARA (Seoul) and KAERI (Jung-eup). In detail, radioisotope usage and safety management were conducted for one week as basic course, RI-Biomics application technology was conducted for two weeks as professional course. To verify performance results of training program, we conducted to journal research, daily reports, and survey on participants. The results show a high level of satisfaction with training programs and continuous intention of involvement in our program. We also need to develop an intensive course to train high-quality human resources and to operate training program continuously. This training program will be used as basic materials for the development of RI-Biomics curriculum for university. Hence, we will expect that our training program contributes in training a professional manpower and develop RI-Biomics technology.