• Title/Summary/Keyword: diffusion limitation

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A Study on Coimmobilized Glucose Oxidase-Catalase System (Glucose Oxidase-Catalase동시 고정화 효소계의 반응)

  • Lee, Suk-Hee;Lee, Sang-Yeol;Uhm, Tai-Boong;Kim, Woo-Jung;Byun, Si-Myung
    • Korean Journal of Food Science and Technology
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    • v.17 no.1
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    • pp.37-40
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    • 1985
  • The reactor performance of a coimmobilized glucose oxidase and catalase enzyme system was investigated. In the determination of efficiencies of glucose oxidase and catalase of dual, mixed and soluble systems, the dual type immobilized one was superior to either the soluble or to the mixed system. In the continuous plugflow bed reactor system of glucose oxidase and catalase, $k-d$, deactivation rare constant of glucose oxidase only and catalase/glucose oxidase = 10 were $1.12\;{\times}\;10^{-2}\;and\;2.17\;{\times}10^{-3}\;hr^{-1}$, respectively. In the effect of ${\tau}$, space time, the point of $O_2$ limitation is $5.5\;g{\cdot}hr/l$ in both catalase/glucose oxidase = 1 and 10. In the effect of $O_2$ concentration to reduce the $O_2$ diffusion limitation, it appeared that ${\tau}\;=\;8.3g{\cdot}r/l$ is the maximum point of $O_2$ concentration in both catalase/glucose oxidase = 1 and 10.

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The Legal Protection Scope and Limitation of Information (정보의 법적 보호범위와 한계)

  • Kim, Hyung-Man;Yang, Myung-Sub
    • Journal of Digital Convergence
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    • v.10 no.11
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    • pp.691-699
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    • 2012
  • "Information", which is circulated in society by information technology development represented by computer, has brought innovation not only to physical civilization, but also deep into our daily lives. This is to say that information has brought fundamental change to its form of existence, and value system through being faster regarding the circulation and the way of management being diverse. As time goes by, this kind of change would stimulate more changes to be made as the development of scientific civilization. Therefore, informatization is one of the important characteristic that defines modern society's essence, but on the other side, information has been taken advantage of that temperament and abused in a lot of different ways. "The Law Regarding Computer Network Diffusion Expansion and Usage Promotion"(1986), as a counterplan of informatization is our nation's first Act about informatization, which enacts national policy and system about this issue. Since then, many laws has been enacted down to "Private Information Protection Act"(2011), forming a comprehensive system. The basic background of these laws are based upon the premise that even if the place where the information is managed is virtual space, rules that are considered valid in the real world should be basically applied in the virtual space. Therefore, the violation of the law in the real world is also considered the violation in the virtual space. This direction of current law regarding information is shared with both the theories and the reality. However, current law system and notion are based upon the premise that the law regards material objects, thus the characteristic of the information, which is "Immaterial Being" is not reflected. Also, the management and approach to this issue is allopathic, exposing many problems. Thus, this paper examines the way of protecting information stipulated in the current law, contemplates its protection scope and limitation, and seeks the direction of the improvement, based on the critical mind explained above.

Surface Physical Properties of W-N Nano Thin Films by Nanotribological Analysis (나노트라이볼로지 분석을 이용한 W-N 나노박막의 표면 물성 연구)

  • Kim, Soo-In;Lee, Kyu-Young;Kim, Joo-Young;Lee, Chang-Woo
    • Journal of the Korean Vacuum Society
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    • v.20 no.6
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    • pp.456-460
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    • 2011
  • Recently, the size of currently-researched components and devices reduces nano-scale. Thus, it is important and emphasizes the analyses of physical properties in nano scale. Especially, the mechanical properties are not over micro-scale components but nano-scale components with different characteristics that has been reported. However, most analytical methods for currently studying in nano-scale are related to spectroscopy and electronics, affected the limitation of viewing size that these methods give only average information. In this research, the representative nanotribology analyses, nano-indenter study the physical and mechanical properties of W-N thin film for nano region and nano depth within nano-scale that the thickness of W-N diffusion barrier has less than tens of nanometers. The Scanning probe microscopy (SPM) study the surface image. From these results, the hardness of W-N thin film underneath the nano-surface decreased from 57.67 GPa to 9.1 GPa according to the increase of nitrogen gas flow. The elastic modulus of W-N thin film underneath the nano-surface also decreased from 575.53 GPa to 178.1 GPa.

Evaluation of 12nm Ti Layer for Low Temperature Cu-Cu Bonding (저온 Cu-Cu본딩을 위한 12nm 티타늄 박막 특성 분석)

  • Park, Seungmin;Kim, Yoonho;Kim, Sarah Eunkyung
    • Journal of the Microelectronics and Packaging Society
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    • v.28 no.3
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    • pp.9-15
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    • 2021
  • Miniaturization of semiconductor devices has recently faced a physical limitation. To overcome this, 3D packaging in which semiconductor devices are vertically stacked has been actively developed. 3D packaging requires three unit processes of TSV, wafer grinding, and bonding, and among these, copper bonding is becoming very important for high performance and fine-pitch in 3D packaging. In this study, the effects of Ti nanolayer on the antioxidation of copper surface and low-temperature Cu bonding was investigated. The diffusion rate of Ti into Cu is faster than Cu into Ti in the temperature ranging from room temperature to 200℃, which shows that the titanium nanolayer can be effective for low-temperature copper bonding. The 12nm-thick titanium layer was uniformly deposited on the copper surface, and the surface roughness (Rq) was lowered from 4.1 nm to 3.2 nm. Cu bonding using Ti nanolayer was carried out at 200℃ for 1 hour, and then annealing at the same temperature and time. The average shear strength measured after bonding was 13.2 MPa.

An Intelligent Decision Support System for Selecting Promising Technologies for R&D based on Time-series Patent Analysis (R&D 기술 선정을 위한 시계열 특허 분석 기반 지능형 의사결정지원시스템)

  • Lee, Choongseok;Lee, Suk Joo;Choi, Byounggu
    • Journal of Intelligence and Information Systems
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    • v.18 no.3
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    • pp.79-96
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    • 2012
  • As the pace of competition dramatically accelerates and the complexity of change grows, a variety of research have been conducted to improve firms' short-term performance and to enhance firms' long-term survival. In particular, researchers and practitioners have paid their attention to identify promising technologies that lead competitive advantage to a firm. Discovery of promising technology depends on how a firm evaluates the value of technologies, thus many evaluating methods have been proposed. Experts' opinion based approaches have been widely accepted to predict the value of technologies. Whereas this approach provides in-depth analysis and ensures validity of analysis results, it is usually cost-and time-ineffective and is limited to qualitative evaluation. Considerable studies attempt to forecast the value of technology by using patent information to overcome the limitation of experts' opinion based approach. Patent based technology evaluation has served as a valuable assessment approach of the technological forecasting because it contains a full and practical description of technology with uniform structure. Furthermore, it provides information that is not divulged in any other sources. Although patent information based approach has contributed to our understanding of prediction of promising technologies, it has some limitations because prediction has been made based on the past patent information, and the interpretations of patent analyses are not consistent. In order to fill this gap, this study proposes a technology forecasting methodology by integrating patent information approach and artificial intelligence method. The methodology consists of three modules : evaluation of technologies promising, implementation of technologies value prediction model, and recommendation of promising technologies. In the first module, technologies promising is evaluated from three different and complementary dimensions; impact, fusion, and diffusion perspectives. The impact of technologies refers to their influence on future technologies development and improvement, and is also clearly associated with their monetary value. The fusion of technologies denotes the extent to which a technology fuses different technologies, and represents the breadth of search underlying the technology. The fusion of technologies can be calculated based on technology or patent, thus this study measures two types of fusion index; fusion index per technology and fusion index per patent. Finally, the diffusion of technologies denotes their degree of applicability across scientific and technological fields. In the same vein, diffusion index per technology and diffusion index per patent are considered respectively. In the second module, technologies value prediction model is implemented using artificial intelligence method. This studies use the values of five indexes (i.e., impact index, fusion index per technology, fusion index per patent, diffusion index per technology and diffusion index per patent) at different time (e.g., t-n, t-n-1, t-n-2, ${\cdots}$) as input variables. The out variables are values of five indexes at time t, which is used for learning. The learning method adopted in this study is backpropagation algorithm. In the third module, this study recommends final promising technologies based on analytic hierarchy process. AHP provides relative importance of each index, leading to final promising index for technology. Applicability of the proposed methodology is tested by using U.S. patents in international patent class G06F (i.e., electronic digital data processing) from 2000 to 2008. The results show that mean absolute error value for prediction produced by the proposed methodology is lower than the value produced by multiple regression analysis in cases of fusion indexes. However, mean absolute error value of the proposed methodology is slightly higher than the value of multiple regression analysis. These unexpected results may be explained, in part, by small number of patents. Since this study only uses patent data in class G06F, number of sample patent data is relatively small, leading to incomplete learning to satisfy complex artificial intelligence structure. In addition, fusion index per technology and impact index are found to be important criteria to predict promising technology. This study attempts to extend the existing knowledge by proposing a new methodology for prediction technology value by integrating patent information analysis and artificial intelligence network. It helps managers who want to technology develop planning and policy maker who want to implement technology policy by providing quantitative prediction methodology. In addition, this study could help other researchers by proving a deeper understanding of the complex technological forecasting field.

A Case of Vancomycin-Resistant Enterococcal Sepsis in Neonate (신생아에서 Vancomycin 내성 장구균 감염 1례)

  • Bae, Soo Jung;Choi, Gui Jean;Kim, Chun Soo;Lee, Sang Lak;Kim, Heung Sik;Kang, Chin Moo
    • Pediatric Infection and Vaccine
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    • v.6 no.2
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    • pp.261-266
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    • 1999
  • Vancomycin-resistant enterococcus(VRE) was first isolated from various specimens of patients with renal failure or leukemia in 1988. Thereafter VRE has been increasing gradually and became one of the clinically important palhogenic organisms currently. We experienced a case of E. faecalis sepsis in a 4 day old neonate. She was born at 39 weeks gestational age with 2,900gm weight by Cesarean section delivery due to breech presentation. She had had swelling and motion limitation of the left knee joint with fever for one day at age of 4 day and was transfered to our hospital. Ultrasonographic examination of her left knee joint showed some inflammatory change. E. faecalis was isolated from the blood. The organism showed resistance to vancomycin on drug susceptibility test using BHI agar screening test and disk diffusion method. After treatment with ampicillin-sulbactam for 3 weeks the baby was improved. Although VRE infection has been considered rare in Korea. considerable number of demonstrative studies about VRE isolation have been reported recently thus adequate countermeasures are needed to reduce the emergence and prevent nosocomial spreading of this organism.

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A Study on the Effect of Determinants of the Dominant Design on Intention to Continuous Use of Smartphone (지배적 디자인의 결정요인이 스마트폰의 지속적 사용의도에 미치는 영향에 관한 연구)

  • Yim, Myung-Seong;Lee, Sang-Hyun
    • Journal of Digital Convergence
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    • v.10 no.10
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    • pp.247-259
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    • 2012
  • The purpose of study is to advance current smartphone research past the limitation it faces being focused primarily on functional performance and to understand the causes of Smartphone diffusion. In order to do this, the dominant design concept was applied in examining the relationship between the determinants of the dominant design and the acceptance of smartphones. The research has yielded results which show that determinants such as technological superiority, number of installed based products, and availability of complementary goods have a positive effect on the intention to use smartphones and the attitude toward its use. Moreover, this study has contributed in broadening the understanding of dominant design by introducing the central concepts of dominant design which are not being dealt with in domestic studies and presenting the major variables which must be considered in the acceptance of smartphones.

A Pressure Applied Low-Level Laser Probe to Enhance Laser Photon Density in Soft Tissue (생체조직내 레이저 광 밀도 향상을 위한 압력 인가형 저출력 레이저 프로브)

  • Yeo, Chang-Min;Park, Jung-Hwan;Son, Tae-Yoon;Lee, Yong-Heum;Jung, Byung-Jo
    • Journal of Biomedical Engineering Research
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    • v.30 no.1
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    • pp.18-22
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    • 2009
  • Laser has been widely used in various fields of medicine. Recently, noninvasive low-level laser therapeutic medical devices have been introduced in market. However, low-level laser cannot deliver enough photon density to expect positive therapeutic results in deep tissue layer due to the light scattering property in tissue. In order to overcome the limitation, this study was aimed to develop a negative pressure applied low-level laser probe to optimize laser transmission pattern and therefore, to improve photon density in soft tissue. In order to evaluate the possibility of clinical application of the developed laser probe, ex-vivo experiments were performed with porcine skin samples and laser transmissions were quantitatively measured as a function of tissue compression. The laser probe has an air suction hole to apply negative pressure to skin, a transparent plastic body to observe variations of tissue, and a small metallic optical fiber guide to support the optical fiber when negative pressure was applied. By applying negative pressure to the laser probe, the porcine skin under the metallic optical fiber guide is compressed down and, at the same time, low-level laser is emitted into the skin. Finally, the diffusion images of laser in the sample were acquired by a CCD camera and analyzed. Compared to the peak intensity without the compression, the peak intensity of laser increased about $2{\sim}2.5$ times and FWHM decreased about $1.67{\sim}2.85$ times. In addition, the laser peak intensity was positively and linearly increased as a function of compression. In conclusion, we verified that the developed low-level laser probe can control the photon density in tissue by applying compression, and therefore, its potential for clinical applications.

Fabrication of Oxide Thin Films Using Nanoporous Substrates (나노기공성 기판을 사용한 산화물박막의 제조)

  • Park, Yong-Il;Prinz, Fritz B.
    • Journal of the Korean Ceramic Society
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    • v.41 no.12 s.271
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    • pp.900-906
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    • 2004
  • Solid oxide fuel cells have a limitation in their low-temperature application due to the low ionic conductivity of electrolyte materials and difficulties in thin film formation on porous gas diffusion layer. These problems can be solved by improvement of ionic conductivity through controlled nanostructure of electrolyte and adopting nanoporous electrodes as substrates which have homogeneous submicron pore size and highly flattened surface. In this study, ultra-thin oxide films having submicron thickness without gas leakage are deposited on nanoporous substrates. By oxidation of metal thin films deposited onto nanoporous anodic alumina substrates with pore size of $20nm{\sim}200nm$ using dc-magnetron sputtering at room temperature, ultra-thin and dense ionic conducting oxide films with submicron thickness are realized. The specific material properties of the thin films including gas permeation, grain/gran boundaries formation, change of crystalline structure/microstructure by phase transition are investigated for optimization of ultra thin film deposition process.

Effects of DO concentration on Simultaneous Nitrification and Denitrification(SND) in a Membrane Bioreactor(MBR) (MBR 단일 반응조에서 용존산소 농도에 따른 동시 질산화-탈질반응(SND)의 영향)

  • Park, Noh-Back;Choi, Woo-Yung;Yoon, Ae-Hwa;Jun, Hang-Bae
    • Korean Journal of Environmental Agriculture
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    • v.28 no.4
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    • pp.371-377
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    • 2009
  • In this study, simultaneous nitrification and denitrification (SND) from synthetic wastewater were performed to evaluate dissolved oxygen(DO) effects on chemical oxygen demand(COD) and nitrogen removal in a single membarne bio-reactor(MBR). DO levels in MBR at Run 1, 2, and 3 were 1.9~2.2, 1.3~1.6, and 0.7~1.0 mg/L, respectively. Experimental results indicated that DO had an important factor to affect COD and total nitrogen(TN) removal. SND were able to be accomplished in the continuous-aeration MBR by controlling ambient DO concentration. It is postulated that, because of the oxygen diffusion limitation, an anoxic micro-zone was formed inside the flocs where the denitrification might occur. From the results of this study, 96% of COD could be removed at DO of 0.7mg/L. At run 2 72.92% of nitrogen was removed by the mechanisms of SND (7.75mg-TN/L in effluent). In this study, SND was successfully occurred in a MBR due to high MLSS that could help to form anoxic zone inside microbial floc at bulk DO concentrations of 1.3~1.6mg/L.