• 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.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.2
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• pp.74-78
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• 2018

Purpose $[^{11}C]$acetate has been proved useful in detecting the myocardial oxygen metabolism and various malignancies including prostate cancer, hepatocellular carcinoma, renal cell carcinoma and brain tumors. The purpose of study was to improve the radiosynthesis yield of $[^{11}C]$acetate on a automated radiosynthesis module. Materials and Methods $[^{11}C]$acetate was prepared by carboxylation of grignard reagent, methylmagnesium chloride, with $[^{11}C]$$CO_2$ gas, followed by hydrolysis with 1 mM acetic acid and purification using solid phase extraction cartridges. The effect of the reaction temperature ($0^{\circ}C$, $10^{\circ}C$, $-55^{\circ}C$) and cyclotron beam time (10 min, 15 min, 20 min, 25 min) on the radiosynthesis yield were investigated in the $[^{11}C]$acetate labeling reaction. Results The maximum radiosynthesis yield was obtained at $-10^{\circ}C$ of reaction temperature. The radioactivities of $[^{11}C]$acetate acquired at $-10^{\circ}C$ reaction temperature was 2.4 times higher than those of $[^{11}C]$acetate acquired at $-55^{\circ}C$. Radiosynthesis yield of $[^{11}C]$acetate increased with increasing cyclotron beam time. Conclusion This study shows that radiosynthesis yield of $[^{11}C]$acetate highly dependent on reaction temperature. The best radiosynthesis yield was obtained in reaction of grignard reagent with $[^{11}C]$$CO_2$ at $-10^{\circ}C$. This radiolabeling conditions will be ideal for routine clinical application.

• The Korean Journal of Nuclear Medicine Technology
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• v.26 no.1
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• pp.42-46
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• 2022

Purpose In the meantime, there have been not many samples that require dilution, and it has been difficult for the examiner to set an appropriate dilution multiple for RIA test item and report the results. Accordingly, it was judged that it was necessary to set the maximum dilution multiple for each test and to verify the upper limit of the clinical reportable range. Therefore, in this study, the maximum dilution multiple for each RIA test was set and the upper limit of the clinical reportable range was verified accordingly Materials and Methods Among all RIA tests conducted at Asan Medical Center, the study treated on 30 types of tests which also conduct the dilution test. Data from March to July 2021 were collected and analyzed. The study was conducted on samples subjected to serial dilutions such as X2, X4 or X10, X10², X10³, X10⁴, X10⁵. Results Among a total of 30 test types, 18 test types have more than 5 N values in the tolerance range of 80~120%. As a result of the verification of maximum dilution multiples, the test set to 10⁴ is 𝛼-fetoprotein and thyroglobulin, and the test set to 10³ is CA-125, CEA, and 𝛽-hCG, and the test set to 10² is Free PSA, PSA, CA15-3, SCC, Ferritin, PTH, Cortisol, and Calcitonin. Tests set to 10 include three categories: 𝛽2-Microglobulin, C-peptide, and Testosterone. Conclusion It is expected that it will contribute to improving the quality of nuclear medicine blood tests as the results of dilution experiments can be reported quickly and accurately through the verification of the clinical reportable range.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.1-25
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• 1982

Limnological study on the physico-chemical properties and biological characteristics of the Lake Ok-Jeong was made from May 1980 to August 1981. For the planktonic organisms in the lake, species composition, seasonal change and diurnal vertical distribution based on the monthly plankton samples were investigated in conjunction with the physico-chemical properties of the body of water in the lake. Analysis of temperature revealed that there were three distinctive periods in terms of vertical mixing of the water column. During the winter season (November-March) the vertical column was completely mixed, and no temperature gradient was observed. In February temperature of the whole column from the surface to the bottom was $3.5^{\circ}C$, which was the minimum value. With seasonal warming in spring, surface water forms thermoclines at the depth of 0-10 m from April to June. In summer (July-October) the surface mixing layer was deepened to form a strong thermocline at the depth of 15-25 m. At this time surface water reached up to $28.2^{\circ}C$ in August, accompanied by a significant increase in the temperature of bottom layer. Maximum bottom temperature was $r5^{\circ}C$ which occurred in September, thus showing that this lake keeps a significant turbulence Aehgh the hypolimnial layer. As autumn cooling proceeded summer stratification was destroyed from the end of October resulting in vertical mixing. In surface layer seasonal changes of pH were within the range from 6.8 in January to 9.0 in guutuost. Thighest value observed in August was mainly due to the photosynthetic activity of the phytoplankton. In the surface layer DO was always saturated throughout the year. Particularly in winter (January-April) the surface water was oversaturated (Max. 15.2 ppm in March). Vertical variation of DO was not remarkable, and bottom water was fairly well oxygenated. Transparency was closely related to the phytoplankton bloom. The highest value (4.6 m) was recorded in February when the primary production was low. During summer transparency decreased hand the lowest value (0.9 m) was recorded in August. It is mainly due to the dense blooming of gnabaena spiroides var. crassa in the surface layer. A. The amount of inorganic matters (Ca, Mg, Fe) reveals that Lake Ok-Jeong is classified as a soft-water lake. The amount of Cl, $NO_3-N$ and COD in 1981 was slightly higher than those in 1980. Heavy metals (Zn, Cu, Pb, Cd and Hg) were not detectable throughout the study period. During the study period 107 species of planktonic organisms representing 72 genera were identified. They include 12 species of Cyanophyta, 19 species of Bacillariophyta, 23 species of Chlorophyta, 14 species of Protozoa, 29 species of Rotifera, 4 species of Cladocera and 6 species of Copepoda. Bimodal blooming of phytoplankton was observed. A large blooming ($1,504\times10^3\;cells/l$ in October) was observed from July to October; a small blooming was present ($236\times10^3\;cells/l$ in February) from January to April. The dominant phytoplankton species include Melosira granulata, Anabaena spiroides, Asterionella gracillima and Microcystis aeruginota, which were classified into three seasonal groups : summer group, winter group and the whole year group. The sumner group includes Melosira granulate and Anabaena spiroides ; the winter group includes Asterionella gracillima and Synedra acus, S. ulna: the whole year group includes Microtystis aeruginosa and Ankistrodesmus falcatus. It is noted that M. granulate tends to aggregate in the bottom layer from January to August. The dominant zooplankters were Thermocpclops taihokuensis, Difflugia corona, Bosmina longirostris, Bosminopsis deitersi, Keratelle quadrata and Asplanchna priodonta. A single peak of zooplankton growth was observed and maximum zooplankton occurrence was present in July. Diurnal vertical migration was revealed by Microcystis aeruginosa, M. incerta, Anabaena spiroides, Melosira granulata, and Bosmina longirostris. Of these, M. granulata descends to the bottom and forms aggregation after sunset. B. longirostris shows fairly typical nocturnal migration. They ascends to the surface after sunset and disperse in the whole water column during night. Foully one species of fish representing 31 genera were collected. Of these 13 species including Pseudoperilnmpus uyekii and Coreoleuciscus splendidus were indigenous species of Korean inland waters. The indicator species of water quality determination include Microcystis aeruginosa, Melosira granulata, Asterionelta gracillima, Brachionus calyciflorus, Filinia longiseta, Conochiloides natans, Asplanchna priodonta, Difflugia corona, Eudorina elegans, Ceratium hirundinella, Bosmina longirostris, Bosminopsis deitersi, Heliodiaptomus kikuchii and Thermocyclops taihokuensis. These species have been known the indicator groups which are commonly found in the eutrophic lakes. Based on these planktonic indicators Lake Ok-Jeong can be classified into an eutrophic lake.

• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.1-9
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• 1995

The slow development of histopathological changes and long period required for stabilization of lesions have suggested that secondary injury processes exacerbate the effect of initial mechanical insult after traumatic spinal cord injury (SCI). The importance of glutamate receptors in the normal functions of spinal cord, in concert with the large body of evidence that points to their involvement in neurotoxicity due to both ischemic and traumatic insults to the CNS, suggested a probable role of glutamate receptors in secondary injury process after traumatic SCI. In order to investigate the involvement of excitatory amino acid in the secondary injury process after SCI, this study examined the effect of dextrorphan, a noncompetitive NMDA receptor antagonist, on the recovery of hindlimb function and the residual tissue at injury site following SCI. Locomotor function was assessed using open field test (21 point scale). At 8 weeks spinal cord tissue was examined using quantitative histopathologic technique. Prior to surgery female Long-Evans rats were adapted to the test environment. Rats received laminectomies (T9/T10), and spinal cord contusions (NYU impactor) were produced by a 10 gm weight dropped 25 mm. DXT (15 or 30 mg/kg, i.p.) or saline was injected 15 min before contusion. Behavioral testing resumed 2 days post-injury and continued twice a week for 8 weeks. No differences between DXT and saline groups were found for hindlimb function and sparing tissue at the lesion site. These results suggest that NMDA receptor might not be involved in secondary injury processes after traumatic SCI.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.245-252
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• 2002

This study was to evaluate the in vitro survival of bovine enucleated MII (eMII) oocytes according to minimum volume cooling (MVC) freezing method and activation timing, and their in vitro development after somatic cell nuclear transfer (SONT). in vitro matured bovine oocytes for 20 h were stained with 5 $\mu\textrm{g}$/$m\ell$ Hoechst, and their 1st polar body and MII plate were removed by enucleation micropipette under UV filter. Also, eMII oocytes were subjected to activation after (group II) and before (group III) vitrification in 5 ${\mu}{\textrm}{m}$ ionomycin added CRlaa medium for 5 min. For vitrification, eMll oocytes were pretreated with EG10 for 5 min, exposed to EG30 for 30 sec and then directly plunged into L$N_2$. Thawing was taken by 4-step procedures at 37$^{\circ}C$. Survived eMII oocytes were subjected to SONT with cultured adult bovine ear cells. Reconstructed oocytes were cultured in 10 $\mu\textrm{g}$/$m\ell$ of cycloheximide and 2.5 $\mu\textrm{g}$/$m\ell$ of cytochalasin D added CRlaa medium for 1 h, and then in 10 $\mu\textrm{g}$/$m\ell$ of cycloheximide added CRlaa medium for 4 h. Subsequently, the reconstructed oocytes were incubated for 2 days and cleaved embryos were further cultured on cumulus-cell monolayer drop in CRlaa medium for 6 days. Survival rates of bovine vitrified-thawed eMII oocytes in group II (activation after vitrification and thawing) and III (activation before vitrification) were 81.0% and 84.9%, respectively. Fusion rates of cytoplasts and oocytes in group II and III were 69.0% and 70.0%, respectively, and their results were not different with non-frozen NT group (control, 75.2%). Although their cleaved rates (53.4% and 58.4%) were not different, cytoplasmic fragment rate in group II (32.8%) was significantly higher than that in group III (15.6%)(P<0.05). Also, subsequent development rate into >morula in group II (8.6%) was low than that in group III(15.6%). However, in vitro development rate in group III was not different with that in control (24.8%). This result suggested that MVC method was appropriate freezing method for the bovine eMII oocytes and vitrified eMII oocytes after pre-activation could support in vitro embryonic development after SONT as equally well as fresh oocytes.

• Journal of Embryo Transfer
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• v.20 no.2
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• pp.105-112
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• 2005

The present study was conducted to examine some factors affecting in vitro development of oocytes from somatic cell nuclear transfer (SCNT) in Korean native goats. Recipient oocytes were surgically collected after superovulation by using CIDR and FSH, PMSG, hCG and estrous synchronization in Korean Native goats. For nuclear transfer, the fibroblasts from caprine ear cells and fetal fibroblasts were surgically harvested and were cultured in vitro until cell confluency in serum-starvation condition (TCM-199 + $0.5\%$ FBS) for 3 to 5 days. The zona pellucidae of matured oocytes were partially drilled by laser irradiation. A single somatic cell was individually transferred into each enucleated oocyte. The reconstructed oocytes were then electrically fused and activated. Activated NT embryos were cultured in mSOF medium supplemented with $0.8\%\;BSA\;6\~7\;day\;at\;39^{\circ}C,\;5\%\;CO_2,\;5\%\;O_2,\;90\%\;N_2$ in air. There were no significant difference in the number of embryos cleaved and 4-cell development between the fibroblast nuclei from mature ear cells and fetal cells, but the rate of 8-cell development was higher (P<0.05) in ear cells $(40.5\%)$ than in fetal cells $(55.5\%)$. However, the embryo development to morula or blastocyst was not significantly different between both the groups$(6.7\%\;vs\;16.0\%)$, respectively. The number of embryo cleaved $(79.0\%)$ were higher (P<0.05) in the oocytes activated with ionomycin+6-DMAP than in the oocytes activated electrically $(9.5\%)$. The development of fused embryos to morula or blastocyst was found $15.6\%$ in ionomycin+6-DMAP, but no morula or blastocysts were developed in electrical stimulation. The development rate of SCNT embryos to morula or blastocyst was love. (P<0.05) in SCNT embryos $(19.0\%\;vs\;0.0\%)$ than that in parthenotes $(66.1\%\;vs\;59.1\%)$. In the parthenotes, the cleavage rate and development to morula or blastocyst were significantly higher (P<0.05) as $86.8\%\;and\;50.0\%$ in ovulated oocytes than in follicular oocytes $(69.0\%\;vs\;23.6\%)$, respectively. These results suggest that some factors Including superovulation treatment, oocyte source, maturation of follicular oocytes, activation method and culture condition may affect in vitro developmental capability of embryos produced by somatic cell nuclear transfer in Korean Native goats, and the fusion rate be greatly low compared with other species.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.426-433
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• 1988

A pot experiment was conducted to find out the effects of application of slacked lime and fused super-phosphate on the lead uptake of upland crops in a lead added soil. Lead concentration of the soils were adjusted to 0, 150, 300mg/kg respectively. The slacked lime was applied at the equivalent amount of lime requirement with extra 150kg/10a, and 2 times for the fused superphosphate. The results obtained were as follows: 1. Lead contents in crops increased in the order: sesame > maize > potato > sweet potato > soybean > green perilla > peanut > red bean. 2. Lead contents in parts of crops were increased in the order; root > stem > leaf > grain. 3. Increasing lead concentration in soils, lead content in the plant was increased and crops yield were decreased. 4. Lead contents in soybean and green perlilla were decreased in slacked lime application treatment. 5. The lead contents in leaf and grain of soybean and green perllila decreased with decreasing in the ratio of Pb/Ca+Mg equivalent in soil. 6. Grain yield were increased in slacked lime, but were decreased in fused superphosphate application treatment. 7. With increasing the soil Pb contents, calcium and phosphate contents were increased in leaf and stem, but calcium was decreased in roots. 8. $1N-NH_4$ OAC soluble Pb contents in soil were 26-50 ppm and 42-70 ppm, respectively, for 150mg/kg and 300mg/kg lead treatments. 9. The soil pH was increased in the order of slacked lime, fused superphosphate and nontreatment.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.329-339
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• 1996

This study is to investigate the effect of mycorrhizal development, growth, nutrient absorption of P. thunbergii seedlings inoculated with Pisolithus tinctorius(Pt. KJ-1) in relation to toxic materials in soil. The concentrations on copper solution applied to the soils were 0, 40, 120, 260, 430ppm. The results are summarized as follows : 1. The germination of P. thunbergii with Pt. increased greater than without ectomycorrhizal fungi. Mycorrhizal development showed a significant decreasing trend at high concentration, and tolerant Cu test with Pt. in agar plate media showed a decreasing trend at a high level. 2. P. thunbergii seedlings inoculated with Pt. showed that the shoot length was significantly promoted at 40, 120ppm copper levels, and that of noninoculated seedlings had the lowest effect in 430ppm copper level. 3. The outer shape of ectomycorrhizal root tips after inoculating Pt. on P. thunbergii seedlings appeared as a monopodial type, a fern-like type, and a cluster-like type at 0ppm, 40ppm levels, but only monopodial type came out at 260ppm, 430ppm copper levels. 4. Root length, no. of juvenile leaves, total length of juvenile leaves, total dry weight, no. of needles and total length of needles of P. thunbergii with Pt. increased greater than those of noninoculated seedling. Growth response of P. thunbergii seedling inoculated with Pt. increased significantly at 40ppm, 120ppm Cu levels. 5. As a result of analysis of growth medium, pH, Na, CEC increased at higher Cu level, and total nitrogen, organic matters, available phosphorous, K, Ca and Mg decreased at 40ppm, 120ppm Cu levels. As a result of an analysis about a copper within soils, it appeared having high Cu-concentration at 0ppm level of an inoculated Pt. and high Cu-concentration in noninoculated Pt. than in inoculated Pt. at higher level. 6. As a result of an analysis of shoot, N, P, and K-concentration were higher in noninoculated seedlings than in inoculated seedlings, and Cu-concentration was higher in inoculated seedlings than in noninoculated seedlings. The analysis of root resulted in a high N-concentration at 40ppm, 120ppm levels, in a high P-concentration in inoculated seedlings and in a high Cu-concentration in noninoculated seedlings. Cu-concentration was significantly higher at root than at shoot.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.7
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• pp.1148-1156
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• 2013

Studies have shown that the preference and average consumption of kimchi among youths have been decreasing partly due to the westernization of the diet. In this study, we examined kimchi consumption status and the annual utilization of 29 kimchi menus registered in the National Education Information System (NEIS) among the students, and then developed seven kimchi menus based on the preference tests and plate waste analysis. Our findings showed that average kimchi consumption by second and fifth graders during lunch time was 19.3% and 17.3%, respectively, of the recommendation (40 g per meal) in the 2010 KDRI. Incidentally, more than 75% of elementary school dieticians answered that ten kimchi menus (31%) registered in the NEIS were never chosen by them in the previous year. The least adopted types of kimchi menu included cooked rice, porridge, stew, pancake, deep-fry and grill. The newly developed kimchi menus included kimchi sauce tofu deopbap, kimchi bacon rice ball, kimchi chicken potato stew, kimchi vegetable fried noodles, kimchi meatballs, kimchi cheese croquette and kimchi potato salad. All these kimchi food items contained 10~20 g of kimchi per serving, and the standardized recipes and nutrient analysis were provided. Kimchi cheese croquette was most liked by fourth graders followed by kimchi sauce tofu deopbap, kimchi meatball and kimchi chicken potato stew in that order. These four menus were again evaluated among second and fifth graders. The kimchi meatballs were most preferred among these groups of students with no leftover but kimchi sauce tofu deopbap was least favorable, producing 17.1% of plate waste. Finally, kimchi cheese croquette and kimchi potato salad were given the highest and lowest scores, respectively, by 87 school dieticians. The findings of this study suggest that efforts on the development of kimchi menu for school food services may help to promote a preference and consumption of kimchi among elementary school students.