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

• Management & Information Systems Review
• /
• v.36 no.3
• /
• pp.131-150
• /
• 2017

The purpose of this study is to observe the spread pattern of open source software (OSS) while establishing relations with surrounding actors during its operation period. In order to investigate the change pattern of participants in the OSS, we use a netnography on the basis of online data, which can trace the change patterns of the OSS depending on the passage of time. For this, the cases of three OSSs (e.g. jQuery, MooTools, and YUI), which are JavaScript frameworks, were compared, and the corresponding data were collected from the open application programming interface (API) of GitHub as well as blog and web searches. This research utilizes the translation process of the actor-network theory to categorize the stages of the change patterns on the OSS translation process. In the project commencement stage, we identified the type of three different OSS-related actors and defined associated relationships among them. The period, when a master commences a project at first, is refined through the course for the maintenance of source codes with persons concerned (i.e. project growth stage). Thereafter, the period when the users have gone through the observation and learning period by being exposed to promotion activities and codes usage respectively, and becoming to active participants, is regarded as the 'leap of participants' stage. Our results emphasize the importance of promotion processes in participants' selection of the OSS for participation and confirm the crowding-out effect that the rapid speed of OSS development retarded the emergence of participants.

• Journal of agricultural medicine and community health
• /
• v.26 no.1
• /
• pp.1-17
• /
• 2001

This study was conducted to investigate the role of drinking pattern in the relationship of alcohol consumption by face-to-face interview in rural elderly(n=994) aged 60~64 in Dalsung County, April to September in 1996. Pattern of alcohol drinking included drinking status, alcohol drinking at the morning without breakfast, average drinks per day, frequency of drinks per month, quantity of alcohol drinking, kind of preferred alcoholic beverage and duration of alcohol drinking. Blood pressure was measured once in each subject using a portable automatic sphygmomanometer. Difference in means of systolic blood pressure, alcohol drinking status, alcohol drinking at the morning without breakfast, and kind of alcoholic beverage were statistically significant before adjusting covariates, but alcohol drinking status and alcohol drinking at the morning without breakfast were statistically significant after adjusting covariates. And difference in means of diastolic blood pressure, kinds of alcoholic beverage was statistically significant before adjusting covariates, but no variables was significant after adjusting covariates. Model I multiple regression for systolic blood pressure that included average drinks per day as the variable of drink pattern, age, educational attainment and, previous history of cardiovascular disease were statistically significant, and multiple regression for diastolic blood pressure, educational attainment, BMI, and previous history of cardiovascular disease were statistically significant. Model II multiple regression for systolic blood pressure that included drinking patterns variables except average drinks per day, previous history of cardiovascular disease were statistically significant. However, multiple regression for diastolic blood pressure, no variables were significant. So, inconsistent with prior research, a positive relationship was not found between average drinks per day and diastolic and systolic blood pressure. The effect of alcohol drinking patterns on blood pressure has public health as well as clinical relevance. The study should be replicated to determine the reliability of our findings.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.6 no.1
• /
• pp.78-95
• /
• 1999

The grafting of a kidney has been found to be the best medical treatment for patients who have renal insufficiency failure, but the patients still have experienced much trouble and apprehension. This study was done to further nursing theory developing for patients who have has a kidney graft from another person. The research method followed grounded theory methodology of Strauss and Corbin. The subjects were three female and four male patients. This study done befween Oct. 1997 and Mar. 1998. All of the subjects were interviewed by the author. Interview were done by the long interview technique and observation. In the process of data analysis, 'heart-boiling' was found to be the core phenomenon. The results were composed to 101 concepts. These concepts were grouped into nineteen categories, and then to twelve categories. There were 12 super-class categories as follows ; 'pain', 'heart-boiling', 'experience of dialysis', 'term of admission to a hospital', 'support of other person', 'dependence on God', 'direction', 'negative reaction', 'positive reaction', 'comfortable', 'lacking', 'acceptance'. In this process, 14 hypotheses were derived from the categories as follows ; (1) The more experience with dialysis that the patients have, the stronger the heart-boiling will tend to be. (2) The less experience with dialysis the patients have, the weaker the heart-boiling will tend to be. (3) The longer admission to hospital the patients have, the stronger the heart-boiling will be. (4) The shorter the admission to hospital the patients have, the weaker the heart-boiling will be. (5) The weaker the intense-grief is, the more positive the reaction to heart-boiling the patients wll have. (6) The stronger the intense-grief is, the more negative the reaction to heart-boiling the patients will have. (7) The stronger the support of other persons that the patients have, the more positive the reaction to heart-boiling the patients will have. (8) The weaker the support of other person that the patients have, the more negative the reaction to heart-boiling the patients will have. (9) The stronger the dependence on God that the patients have, the mure positive reaction to heart-boiling the patients will have. (10) The weaker the dependence on God that the patients have, the more negative reaction to heart-boiling the patients will have. (11) The more positive thoughts that the patients have, the more positive reaction to heart-boiling the patinets will have. (12) The more negative thoughts that the patients have, the more negative reaction to heart-boiling the patients will have. (13) The more positive reaction the patients have, the more free from heart-boiling the patients tend to be. (14) The more negative reaction the patients have, the less free from heart-boiling the patients tend to be. From the analysis of observed data and comparing each class, I concluded that there are four formula relation types between reaction of patients and heart-boiling. (1) If patients have the experience of dialysis, have a long term admission to hospital, are strong in heart-boiling, depend on God, have positive thoughts and another's strong support, they experience release by positive reaction to the intense-grief. (2) If patients have the experience of dialysis, have a short term admission to hospital, are weak in heart-boiling, do not depend on God, have negative thoughts, and have few supports from others, they experience attachment to heart-boiling though a negative reaction. (3) If patients have the experience of dialysis, have a long term admission to hospital, are strong in heart-boiling, do not depend on God, and have negative thoughts, they experience attachment to heart-boiling through negative reaction in spite of support from another. (4) If patients have the experience of dialysis, have a long term admission into hospital, are strong in heart-boiling and satisfaction is low, but they have positive thoughts, then they experience acceptance and harmony through the positive reaction to heart-boiling. The results of this study are expected to help the way nurses care for patients who have had a kidney graft from another.

• Clean Technology
• /
• v.20 no.2
• /
• pp.189-201
• /
• 2014

Partial oxidation, $CO_2$ reforming and the oxidative $CO_2$ reforming of $CH_4$ to produce synthesis gas over supported Ni hydrotalcite-type ($Ni_{0.5}Ca_{2.5}Al$ catalyst) catalysts were carried out and the effects of metal supports (i.e.; Mg and Ca) on the formation of a stable double-layer structure on the catalysts were evaluated. The $CH_4$ reforming stability was determined to be affected by the differences in the interaction strength between the active Ni ions and support metal ions. Only a Ni-Mg-Al composition produced a highly stable hydrotalcite-type double-layered structure; while the Ni-Ca-Al-type composition did not. Such structure provides excellent stability for the catalyst (-80% efficiency) as confirmed by the long-term $CO_2$ reforming test (-100 h), while the Ni-Ca-Al catalyst exhibited deactivation phases starting at the beginning of the reaction. The interaction strength between the active metal (Ni) and the supporting components (Mg and Al) was determined by temperature-programed reduction (TPR) analyses. The affinity was also confirmed by the TPR temperature because the Ni-Mg-Al catalyst required a higher temperature to reduce the Ni relative to the Ni-Ca-Al catalyst. The highest initial activity for synthesis gas production was observed for the $Ni_{0.5}Ca_{2.5}Al$ catalyst; however, this activity decreased quickly due to coke formation. The $Ni_{0.5}Ca_{2.5}Al$ catalyst exhibited a high reactivity and was more stable than the other catalysts because it had a higher resistance to coke formation.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2003.04a
• /
• pp.61-62
• /
• 2003

Clonal propagation of high-value forest trees through somatic embryogenesis (SE) has the potential to rapidly capture the benefits of breeding or genetic engineering programs and to improve raw material uniformity and quality. A major barrier to the commercialization of this technology is the low quality of the resulting embryos. Several factors limit commercialization of SE for Corsican pine, including low initiation rates, low culture survival, culture decline causing low or no embryo production, and inability of somatic embryos to fully mature, resulting in low germination and reduced vigour of somatic seedlings. The objective was to develop a Corsican pine maturation medium that would produce cotyledonary embryos capable of germination. Treatments were arranged in a completely randomized design. Data were analyzed by analysis of variance, and significant differences between treatments determined by multiple range test at P=0.05. Corsican pine (Pinus nigra var. maritima) cultures were initiated on modified !P6 medium. Modifications of the same media were used for culture multiplication and maintenance. Embryogenic cultures were maintained on the same medium semi solidified with 2.5 g/l Gelrite. A maturation medium, capable of promoting the development of Corsican pine somatic embryos that can germinate, is a combination of iP6 modified salts, 2% maltose, 13% polyethylene glycol (PEG), 5 mg!l abscisic acid (ABA), and 2.5 g/l Gelrite. After initiation and once enough tissue developed they were grown in liquid medium. Embryogenic cell suspensions were established by adding 0.951.05 g of 10- to 14-day-old semisolid-grown embryogenic tissue to 9 ml of liquid maintenance media in a 250ml Erlenmeyer flask. Cultures were then incubated in the dark at 2022$^{\circ}$C and rotated at 120 rpm. After 2.53 months on maturation medium, somatic embryos were selected that exhibited normal embryo shape. Ten embryos were placed horizontally on 20 ml of either germination medium ($\frac{2}{1}$strength Murashige and Skoog (1962) salts with 2.5 g/l activated charcoal) or same medium with copper sulphate adjusted to 0.25 mg/1 to compensate for copper adsorption by activated carbon. 2% and 4% maltose was substituted by 7.5% and 13% PEG respectively to improve the yield of the embryos. Substitution of' maltose with PEG was clearly beneficial to embryo development. When 2% of the maltose was replaced with 7.5% PEG, many embryos developed to large bullet-shaped embryos. At latter stages of development most embryos callused and stopped development. A few short, barrel-shaped cotyledonary embryos formed that were covered by callus on the sides and base. When 4% of the maltose was removed and substituted with 13% PEG, the embryos developed further, emerging from the callus and increasing yield slightly. Microscopic examination of the cultures showed differing morphologies, varying from mostly single cells or clumps to well-formed somatic embryos that resembled early zygotic embryos only liquid cultures with organized early-stag. A procedure for converting and acclimating germinants to growth in soil and greenhouse conditions is also tested. Seedling conversion and growth were highly related to the quality of the germinant at the time of planting. Germinants with larger shoots, longer, straighter hypocotyls and longer roots performed best. When mature zygotic embryos germinate the root emerges, before or coincident with the shoot. In contrast, somatic embryos germinate in reverse sequence, with the cotyledons greening first, then shoot emergence and then, much later, if at all, the appearance of the root. Somatic seedlings, produced from the maturation medium, showed 100% survival when planted in a field setting. Somatic seedlings showed normal yearly growth relative to standard seedlings from natural seed.

• The Korean Journal of Air & Space Law and Policy
• /
• v.29 no.1
• /
• pp.199-236
• /
• 2014

This paper analyses from the perspective of distributive justice the legal mechanisms for international allocation of orbital slots, which are of co-owned nature and thereby limited natural resources in outer space. The allocative function is delegated to the International Telecommunication Union. The Radio Regulation, amongst such other legal instruments as the Constitution and Convention, by which the ITU and contracting States thereof abides, dictates how the orbital positions are distributed. Thus, the RR is thoroughly reviewed in the essay. The mechanisms are in a broad sense categorized into two systems: 'a posteriori system' where the 'first come, first served' principle prevails; and 'a priori system' designed to foster the utilisation of the slots by those who lack space resources and are, in especial, likely to be marginalised under the former system. The argument proceeds on the premise that a posteriori system places the under-resourced States in unfavourable positions in the securement of the slots. In contrast with this notion, seven factors were instantiated for an assertion that the degradation of the distributive justice derived from the 'first come, first served' rule, which lays the foundation for the system, could be either mitigated or counterbalanced by the alleged exceptions to the rule. However, the author of this essay argues for counterevidences against the factors and thereby demonstrating that the principle still remains as an overwhelming doctrine, posing a threat to the pursuit of fair allocation. The elements he set forth are as in the following: 1) that the 'first come, first served' principle only applies to assignments capable of causing harmful interferences; 2) the interoperability of the principle with the 'rule of conformity' with the all the ITU instruments; 3) the viability of alternative registrations, as an exception of the application of the principle, on the condition of provisional and informational purposes; 4) another reference that matters in deciding the priority: the types of services in the TFA; 5) the Rule of Procedure H40 proclaiming a ban on taking advantage of coming first to the Register; 6) the technical factors and equity-oriented norms under international and municipal laws along with; 7) the changes of 'basic characteristics' of registered assignments. The second half of this essay illustrates by examining the relevant Annexes to the Regulation that the planned allocation, i.e., a priori system, bear the structured flaws that hinder the fulfillment of the original purpose of the system. The Broadcasting and Fixed Satellite Systems are the reviewed Plans in which the 'first come, first served' principle re-emerges in the end as a determining factor to grant the 'right to international recognition' to administrations including those who has not the allotted portions in the Plan.

• Journal of Intelligence and Information Systems
• /
• v.16 no.2
• /
• pp.129-141
• /
• 2010

An Internet shopping mall for clothing operates a warehouse for packing and shipping products to fulfill its orders. All the products in the warehouse are put into the boxes of same brands and the boxes are stored in a row on shelves equiped in the warehouse. To make picking and managing easy, boxes of the same brands are located side by side on the shelves. When new products arrive to the warehouse for storage, the products of a brand are put into boxes and those boxes are located adjacent to the boxes of the same brand. If there is not enough space for the new coming boxes, however, some boxes of other brands should be moved away and then the new coming boxes are located adjacent in the resultant vacant spaces. We want to minimize the movement of the existing boxes of other brands to another places on the shelves during the warehousing of new coming boxes, while all the boxes of the same brand are kept side by side on the shelves. Firstly, we define the adjacency of boxes by looking the shelves as an one dimensional series of spaces to store boxes, i.e. cells, tagging the series of cells by a series of numbers starting from one, and considering any two boxes stored in the cells to be adjacent to each other if their cell numbers are continuous from one number to the other number. After that, we tried to formulate the problem into an integer programming model to obtain an optimal solution. An integer programming formulation and Branch-and-Bound technique for this problem may not be tractable because it would take too long time to solve the problem considering the number of the cells or boxes in the warehouse and the computing power of the Internet shopping mall. As an alternative approach, we designed a fast heuristic method for this reallocation problem by focusing on just the unused spaces-empty cells-on the shelves, which results in an assignment problem model. In this approach, the new coming boxes are assigned to each empty cells and then those boxes are reorganized so that the boxes of a brand are adjacent to each other. The objective of this new approach is to minimize the movement of the boxes during the reorganization process while keeping the boxes of a brand adjacent to each other. The approach, however, does not ensure the optimality of the solution in terms of the original problem, that is, the problem to minimize the movement of existing boxes while keeping boxes of the same brands adjacent to each other. Even though this heuristic method may produce a suboptimal solution, we could obtain a satisfactory solution within a satisfactory time, which are acceptable by real world experts. In order to justify the quality of the solution by the heuristic approach, we generate 100 problems randomly, in which the number of cells spans from 2,000 to 4,000, solve the problems by both of our heuristic approach and the original integer programming approach using a commercial optimization software package, and then compare the heuristic solutions with their corresponding optimal solutions in terms of solution time and the number of movement of boxes. We also implement our heuristic approach into a storage location assignment system for the Internet shopping mall.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.42 no.2
• /
• pp.52-64
• /
• 2014

I the recent years, Seoul, Daejeon, Changwon, and Suncheon have started to strengthen P.R. efforts on eco-brands produced by the city and to publicize as a specialized tourist city in an attempt to change their identity and image. However, there is actually a question whether the efforts of the local governments have any direct impact on satisfaction with urban living environments and the attractions of the city. The purpose of this study was to examine the awareness of residents and visitors about the attractions of Suncheon City as an eco-city and to discuss the planning criteria for the eco-city brand building and its management. The research data was collected in Suncheon City and main results of this study are as follows. The residents and the visitors investigated were satisfied with the environmental friendliness of this city and regarded it as an eco-city. As a result of asking them why they viewed the city as an eco-city, many of the residents cited diverse green tracts of land as the reason, whereas the visitors replied they were satisfied with the state of marshy areas preserved by the city. The psychological factors related to the satisfaction of the eco-city by the residents were composed of four factors, 'cultural factor', 'urban infrastructure factor', 'ecological factor' and 'scenery factor'. The visitors were composed of five factors, 'cultural factor', 'urban infrastructure factor', 'ecological factor', 'scenery factor' and 'amenity factor'. Out of the factors, the cultural factor and the urban infrastructure factor were found to exert the largest influence on the overall satisfaction of the residents and the visitors. The ISA(Importance-Satisfaction Analysis) was made, the residents and the visitors gave top priority to 'diversity of natural attractions', 'pleasant season and weather', 'beautiful scenery', 'diversity of rare animals and plants', 'diversity of parks', 'green areas and streets', 'broad ecological area' and 'the preservation of marshy areas' among the attractions of the eco-city. They placed importance on the activation of green traffic and walking environments as well, but they weren't satisfied with the state of the two in the city. Therefore there was much room for improvement in that regard.

• Applied Biological Chemistry
• /
• v.22 no.3
• /
• pp.135-141
• /
• 1979

These experiments were conducted to investigate the conditions of the acid protease production by Rhizopus oryzae and the characteristics of crude enzyme. The results obtained were as follows: 1. The optimum culture time and the optimum amount of added water to the wheat bran medium were about 48 hrs and $80{\sim}120%$, respectively. 2. The addition of $(NH_4)_6Mo_7O_{24},\;(NH_4)_2SO_4,\;NH_4NO_3$, casein, and albumin, respectively, as nitrogen sources to the wheat bran medium was effective. Of these, the optimum concentrations of addition of $(NH_4)_6Mo_7O_{24}$ and casein which were the most effective were 0.1% and 1.0%, respectively. 3. The addition of glucose, galactose, maltose, lactose, and soluble starch, respectively, as carbon sources to the wheat bran medium was effective. Of these, the optimum concentration of addition of glucose which was the most effective was 3.0%. 4. The addition of $KH_2PO_4$ as a phosphate salt to the wheat bran medium was effective. The optimum concentration of addition of $KH_2PO_4$ was 0.3%. 5. The optimum pH for the enzyme action was 2.4, the optimum temperature about $40^{\circ}C$, and the stable pH range $2.0{\sim}5.0$. The enzyme was stab1e below $40^{\circ}C$. 6. The enzyme activity increased rapidly for 10 minutes after addition, thereafter it increased slowly. 7. The enzyme activity increased rapidly to 2 ml of addition, but nearly did not increase at the amounts greater than 2ml.