Prestack depth migration using straight ray technique(SRT)

Kirchhoff prestack depth migration requires an elaborate book-keeping effort and a massive IO process to construct Kirchhoff hyperbolas. In order to avoid the complexity of the programming code and the massive IO process, we propose a straight ray technique (SRT) for traveltimi calculations in Kirchhoff migration. Since all the rays are straight in. polar coordinates for the 2D velocity model,or in sphericalc oordinatesf or the 3D velocity model, traveltimesc an be simply computed along a straight ray for a given source-receiver configuration,without suffering from shadow zones and caustics, and used directly for building Kirchhoff hyperbolas. In this way, we clrcumvent the substantial IO process required for reading traveltimes on a disk and save computationals torage.N umerical examplesd emonstrateth at SRT computest raveltimesi ntermediate between first-arrival traveltimes and the most energetic arrival traveltimes, resulting in better images than the first arrival traveltimes for the 2D IFP Marmousi data. With the implementation of SRT for 2D Kirchhoff migration, we successfully extend our SRT to 3D Kirchhoff misration for the SECiEAGE salr dome data.This work was financially supported by the National Laboratory Project of the Ministry of Science and Technology, Brain Korea 21 Project of the Ministry of Education, grant No. R05-2000-00003 from the Basic Research Program of the Korea Science & Engineering Foundation, and grant No. PM10300 from the Korea Ocean Research & Development Institute

Diagnosis and Prioritization of Vulnerable Areas of Urban Ecosystem Regulation Services

Rapid urbanization and population growth have led to drastic degradation of urban ecosystem regulation services (ERS). Urgently needed is the identification of vulnerable areas where ERS are being intensively deteriorated, and preparation of measures to respond to them. This study developed a framework to diagnose and prioritize vulnerable areas of urban ERS. The vulnerability of urban ERS that include carbon storage capacity, flood-risk mitigation capacity, and heat stress reduction capacity was diagnosed with a resolution of 100 m × 100 m grid. Priority areas to improve urban ERS were delineated using hot spot analysis, and the diagnosed results of the urban ERS were categorized by eight combination types including exposure, sensitivity, and adaptability. The spatial and societal problems included in the priority areas were further investigated by overlaying hot spot areas with eight combination maps. Finally, spatial management measures for the priority areas were suggested based on the analysis results. From the detailed diagnosis results of the vulnerable ERS areas, this study provides a framework to link the concept of ERS vulnerability with urban planning. Furthermore, effective spatial planning guidelines can be prepared to improve urban ERS by spatially delineating priority areas to improve urban ERS vulnerability

Diagnosis and Prioritization of Vulnerable Areas of Urban Ecosystem Regulation Services

Rapid urbanization and population growth have led to drastic degradation of urban ecosystem regulation services (ERS). Urgently needed is the identification of vulnerable areas where ERS are being intensively deteriorated, and preparation of measures to respond to them. This study developed a framework to diagnose and prioritize vulnerable areas of urban ERS. The vulnerability of urban ERS that include carbon storage capacity, flood-risk mitigation capacity, and heat stress reduction capacity was diagnosed with a resolution of 100 m × 100 m grid. Priority areas to improve urban ERS were delineated using hot spot analysis, and the diagnosed results of the urban ERS were categorized by eight combination types including exposure, sensitivity, and adaptability. The spatial and societal problems included in the priority areas were further investigated by overlaying hot spot areas with eight combination maps. Finally, spatial management measures for the priority areas were suggested based on the analysis results. From the detailed diagnosis results of the vulnerable ERS areas, this study provides a framework to link the concept of ERS vulnerability with urban planning. Furthermore, effective spatial planning guidelines can be prepared to improve urban ERS by spatially delineating priority areas to improve urban ERS vulnerability

Comparative Evaluation of the Performance of Sterile Filters for Bioburden Protection and Final Fill in Biopharmaceutical Processes

Sterile filtration processes are widely used in the production of biotherapeutics for microorganism removal and product sterility. Sterile filtration processes can be applied to buffer preparation and cell culture media preparation in biotherapeutics processes, and to final sterilization or final filling in downstream processes. Owing to their broad range of applications in bioprocessing, various 0.2/0.22 μm sterile filters with different polymer materials (i.e., hydrophilic PVDF and PES) and nominal pore sizes are commercially available. The objective of this study was to evaluate two different commercial sterile filters in terms of filtration performance in various sterile filtration processes of biopharmaceutical production. The results demonstrate the importance of choosing the appropriate filter considering the process type and target removal/transport product to ensure efficient sterile filtration in the production of biotherapeutics

Free-Standing, Single-Monomer-Thick Two-Dimensional Polymers through Covalent Self-Assembly in Solution

The design and synthesis of two-dimensional (2D) polymers is a challenging task, hitherto achieved in solution only through the aid of a solid surface "template" or preorganization of the building blocks in a 2D confined space. We present a novel approach for synthesizing free-standing, covalently bonded, single-monomer-thick 2D polymers in solution without any preorganization of building blocks on solid surfaces or interfaces by employing shape-directed covalent self-assembly of rigid, disk-shaped building blocks having laterally predisposed reactive groups on their periphery. We demonstrate our strategy through a thiol-ene "click" reaction between (allyloxy)(12)CB[6], a cucurbit[6]uril (CB[6]) derivative with 12 laterally predisposed reactive alkene groups, and 1,2-ethanedithiol to synthesize a robust and readily transferable 2D polymer. We can take advantage of the high binding affinity of fully protonated spermine (positive charges on both ends) to CB[6] to keep each individual polymer sheet separated from one another by electrostatic repulsion during synthesis, obtaining, for the first-time ever, a single-monomer-thick 2D polymer in solution. The arrangement of CB[6] repeating units in the resulting 2D polymer has been characterized using gold nanoparticle labeling and scanning transmission electron microscopy. Furthermore, we have confirmed the generality of our synthetic approach by applying it to different monomers to generate 2D polymers. Novel 2D polymers, such as our CB[6] derived polymer, may be useful in selective transport, controlled drug delivery, and chemical sensing and may even serve as well-defined 2D scaffolds for ordered functionalization and platforms for bottom-up 3D construction.X118381sciescopu

Nanowire-on-Nanowire: All-Nanowire Electronics by On-Demand Selective Integration of Hierarchical Heterogeneous Nanowires

Exploration of the electronics solely composed of bottom-up synthesized nanowires has been largely limited due to the complex multistep integration of diverse nanowires. We report a single-step, selective, direct, and on-demand laser synthesis of a hierarchical heterogeneous nanowire-on-nanowire structure (secondary nanowire on the primary backbone nanowire) without using any conventional photolithography or vacuum deposition. The highly confined temperature rise by laser irradiation on the primary backbone metallic nanowire generates a highly localized nanoscale temperature field and photothermal reaction to selectively grow secondary branch nanowires along the backbone nanowire. As a proof-of-concept for an all-nanowire electronics demonstration, an all-nanowire UV sensor was successfully fabricated without using conventional fabrication processes

Free-Standing, Single-Monomer-Thick Two-Dimensional Polymers through Covalent Self-Assembly in Solution

The design and synthesis of two-dimensional (2D) polymers is a challenging task, hitherto achieved in solution only through the aid of a solid surface “template” or preorganization of the building blocks in a 2D confined space. We present a novel approach for synthesizing free-standing, covalently bonded, single-monomer-thick 2D polymers in solution without any preorganization of building blocks on solid surfaces or interfaces by employing shape-directed covalent self-assembly of rigid, disk-shaped building blocks having laterally predisposed reactive groups on their periphery. We demonstrate our strategy through a thiol–ene “click” reaction between (allyloxy)₁₂CB­[6], a cucurbit[6]­uril (CB[6]) derivative with 12 laterally predisposed reactive alkene groups, and 1,2-ethanedithiol to synthesize a robust and readily transferable 2D polymer. We can take advantage of the high binding affinity of fully protonated spermine (positive charges on both ends) to CB[6] to keep each individual polymer sheet separated from one another by electrostatic repulsion during synthesis, obtaining, for the first-time ever, a single-monomer-thick 2D polymer in solution. The arrangement of CB[6] repeating units in the resulting 2D polymer has been characterized using gold nanoparticle labeling and scanning transmission electron microscopy. Furthermore, we have confirmed the generality of our synthetic approach by applying it to different monomers to generate 2D polymers. Novel 2D polymers, such as our CB[6] derived polymer, may be useful in selective transport, controlled drug delivery, and chemical sensing and may even serve as well-defined 2D scaffolds for ordered functionalization and platforms for bottom-up 3D construction