120 research outputs found
The institutional development and outcomes of water partnerships in Korea: a comparative case study based on a modified institutional analysis and development (IAD) framework
This thesis examines how new types of water governance institutions, water partnerships, emerged and performed in Korea, a centralised state-driven society. Beyond conventional water management by either government or market, new forms of governance have been sought to address problems such as under-provision, pollution and water conflict. This study investigates voluntary water partnerships as a leading example of new water governance in East Asia. Conceptually, it uses a modified institutional approach, the Institutional Analysis and Development (IAD) framework, to examine how global water reform discourses informed social actors in the design and implementation of regional and urban water partnerships in Korea. A comparative case analysis of six water partnerships finds that co-governance institutions emerged and operated in a complex linkage with existing water governance systems. For the three urban water partnerships, local actors actively seized opportunities to rehabilitate long abandoned urban streams. For the three regional water partnerships, public and private sector actors successfully negotiated partnership agreements, focusing on the restoration of polluted water sources. A modified IAD framework captured these complicated interactions among stakeholders within multi-layered water governance structures. An attitudinal survey of partnership members complemented the comparative case studies by assessing how the partnerships performed according to selected evaluation criteria. A multi-criteria assessment of the data reveals three key findings. First, the partnerships achieved mainly positive procedural and socio-economic outcomes in water management. Second, observed lower environmental outcomes result mainly from the interlinked features of water resources management and the partnerships’ relatively brief history. Third, the overall findings indicate that the outcomes of co-governance institutions tended to be contextual. The scale of organisations and of the water resources concerned did not determine the outcomes of the water partnerships. Thus, this finding challenges the claim that ‘smaller is better’ in collaborative governance. This study concludes that the voluntary co-management of shared water resources by the six partnerships have simultaneously brought some solutions as well as costs to water governance in Korea. The design and development of co-management institutions for water governance requires a greater understanding of local and national settings, as well as the facilitative role of national government. Co-operation between new co-governance institutions and existing water institutions is vital to long-term, effective water management
Semi-Automatic Measurement of the Airway Dimension by Computed Tomography Using the Full-With-Half-Maximum Method: a Study of the Measurement Accuracy according to the Orientation of an Artificial Airway
parameters on the correct measurement of the airway dimension.
Materials and Methods: An airway phantom with 11 poly-acryl tubes of various
lumen diameters and wall thicknesses was scanned using a 16-MDCT (multidetector
CT) at various tilt angles (0, 30, 45, and 60 ). The CT images were reconstructed
at various reconstruction kernels and thicknesses. The axis of each airway
was determined using the 3D thinning algorithm, with images perpendicular to
the axis being reconstructed. The luminal radius and wall thickness was measured
by the full-width-half-maximum method. The influence of the CT parameters (the
size of the airways, obliquity on the radius and wall thickness) was assessed by
comparing the actual dimension of each tube with the estimated values.
Results: The 3D thinning algorithm correctly determined the axis of the oblique
airway in all tubes (mean error: 0.91+-0.82 ). A sharper reconstruction kernel,
thicker image thickness and larger tilt angle of the airway axis resulted in a significant
decrease of the measured wall thickness and an increase of the measured
luminal radius. Use of a standard kernel and a 0.75-mm slice thickness resulted
in the most accurate measurement of airway dimension, which was independent
of obliquity.
Conclusion: The airway obliquity and imaging parameters have a strong influence
on the accuracy of the airway wall measurement. For the accurate measurement
of airway thickness, the CT images should be reconstructed with a
standard kernel and a 0.75 mm slice thickness.This work was supported by the Korea Science and
Engineering Foundation (KOSEF) grant funded by the
Korea government (MOST) (No. R01-2006-000-11244-0)
All-Solution-Processed InGaO 3
We fabricated the crystallized InGaZnO thin films by sol-gel process and high-temperature annealing at 900°C. Prior to the deposition of the InGaZnO, ZnO buffer layers were also coated by sol-gel process, which was followed by thermal annealing. After the synthesis and annealing of the InGaZnO, the InGaZnO thin film on the ZnO buffer layer with preferred orientation showed periodic diffraction patterns in the X-ray diffraction, resulting in a superlattice structure. This film consisted of nanosized grains with two phases of InGaO3(ZnO)1 and InGaO3(ZnO)2 in InGaZnO polycrystal. On the other hand, the use of no ZnO buffer layer and randomly oriented ZnO buffer induced the absence of the InGaZnO crystal related patterns. This indicated that the ZnO buffer with high c-axis preferred orientation reduced the critical temperature for the crystallization of the layered InGaZnO. The InGaZnO thin films formed with nanosized grains of two-phase InGaO3(ZnO)m superlattice showed considerably low thermal conductivity (1.14 Wm−1 K−1 at 325 K) due to the phonon scattering from grain boundaries as well as interfaces in the superlattice grain
An Optimization of Composition Ratio among Triple-Filled Atoms in In
Bulk nanostructured materials are important as energy materials. Among thermoelectric materials, the skutterudite system of CoSb3 is a representative material of bulk nanostructured materials. Filling a skutterudite structure with atoms that have different localized frequencies (also known as triple filling) was reported to be effective for lowering thermal conductivity. Among studies representing superior power factors, In-filled skutterudite systems showed higher Seebeck coefficients. This study sought to optimize the composition ratio among the triple-filled atoms in an In0.3-x-yBaxCeyCo4Sb12 system. The composition dependence of the thermoelectric properties was investigated for specimens with different ratios among the three kinds of filler atoms in the In0.3-x-yBaxCeyCo4Sb12 system. In addition, the process variables were carefully optimized for filled skutterudite systems to obtain a maximum ZT value
Proper Activity of Histone H3 Lysine 4 (H3K4) Methyltransferase Is Required for Morphogenesis during Zebrafish Cardiogenesis
While increasing evidence indicates the important function of histone methylation during development, how this process influences cardiac development in vertebrates has not been explored. Here, we elucidate the functions of two histone H3 lysine 4 (H3K4) methylation enzymes, SMYD3 and SETD7, during zebrafish heart morphogenesis using gene expression profiling by whole mount in situ hybridization and antisense morpholino oligonucleotide (MO)-based gene knockdown. We find both smyd3 and setd7 are highly expressed within developing zebrafish heart and knock-down of these genes led to severe defects in cardiac morphogenesis without altering the expressions pattern of heart markers, including cmlc2, vmhc, and amhc. Furthermore, double knock-down by coinjection of smyd3 and setd7 MOs caused the synergistic defects in heart development. As similar to knock-down effect, overexpression of these genes also caused the heart morphogenesis defect in zebrafish. These results indicate that histone modifying enzymes, SMYD3 and SETD7, appear to function synergistically during heart development and their proper functioning is essential for normal heart morphogenesis during development
Observation of oxide precipitates in InN nanostructures
We observed the formation of oxide precipitates (bcc-In(2)O(3)) in InN nanostructures formed during metal-organic chemical vapor deposition (MOCVD) and/or subsequent postgrowth procedures in H(2) ambient. It was found that InN is extremely unstable in H(2) ambient and the activation energy of N(2) desorption of InN is measured to be similar to 0.28 eV, which is one order of magnitude smaller than that of reported value of InN in vacuum. Instability of InN nanostructures under H(2) ambient together with residual oxidant in the reactor facilitates the formation of indium oxide precipitates in the nanostructure matrix during MOCVD or the oxidation of residual indium at the surface, resulting in indium oxide dots.open3
Solution-processed near-infrared Cu(In,Ga)(S,Se)(2) photodetectors with enhanced chalcopyrite crystallization and bandgap grading structure via potassium incorporation
Although solution-processed Cu(In,Ga)(S,Se)(2) (CIGS) absorber layers can potentially enable the low-cost and large-area production of highly stable electronic devices, they have rarely been applied in photodetector applications. In this work, we present a near-infrared photodetector functioning at 980 nm based on solution-processed CIGS with a potassium-induced bandgap grading structure and chalcopyrite grain growth. The incorporation of potassium in the CIGS film promotes Se uptake in the bulk of the film during the chalcogenization process, resulting in a bandgap grading structure with a wide space charge region that allows improved light absorption in the near-infrared region and charge carrier separation. Also, increasing the Se penetration in the potassium-incorporated CIGS film leads to the enhancement of chalcopyrite crystalline grain growth, increasing charge carrier mobility. Under the reverse bias condition, associated with hole tunneling from the ZnO interlayer, the increasing carrier mobility of potassium-incorporated CIGS photodetector improved photosensitivity and particularly external quantum efficiency more than 100% at low light intensity. The responsivity and detectivity of the potassium-incorporated CIGS photodetector reach 1.87 A W-1 and 6.45 x 10(10) Jones, respectively, and the - 3 dB bandwidth of the device extends to 10.5 kHz under 980 nm near-infrared light
Embedding Covalency into Metal Catalysts for Efficient Electrochemical Conversion of CO_2
CO_2 conversion is an essential technology to develop a sustainable carbon economy for the present and the future. Many studies have focused extensively on the electrochemical conversion of CO_2 into various useful chemicals. However, there is not yet a solution of sufficiently high enough efficiency and stability to demonstrate practical applicability. In this work, we use first-principles-based high-throughput screening to propose silver-based catalysts for efficient electrochemical reduction of CO_2 to CO while decreasing the overpotential by 0.4–0.5 V. We discovered the covalency-aided electrochemical reaction (CAER) mechanism in which p-block dopants have a major effect on the modulating reaction energetics by imposing partial covalency into the metal catalysts, thereby enhancing their catalytic activity well beyond modulations arising from d-block dopants. In particular, sulfur or arsenic doping can effectively minimize the overpotential with good structural and electrochemical stability. We expect this work to provide useful insights to guide the development of a feasible strategy to overcome the limitations of current technology for electrochemical CO_2 conversion
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