Green-Schwarz Strings in TsT-transformed backgrounds

We consider classical strings propagating in a background generated by a sequence of TsT transformations. We describe a general procedure to derive the Green-Schwarz action for strings. We show that the U(1) isometry variables of the TsT-transformed background are related to the isometry variables of the initial background in a universal way independent of the details of the background. This allows us to prove that strings in the TsT-transformed background are described by the Green-Schwarz action for strings in the initial background subject to twisted boundary conditions. Our construction implies that a TsT transformation preserves integrability properties of the string sigma model. We discuss in detail type IIB strings propagating in the \g_i-deformed AdS_5 x S^5 space-time, find the twisted boundary conditions for bosons and fermions, and use them to write down an explicit expression for the monodromy matrix. We also discuss string zero modes whose dynamics is governed by a fermionicgeneralization of the integrable Neumann model.Comment: 33 pages, latex, v2: typos correcte

High-Conductivity Two-Dimensional Polyaniline Nanosheets Developed on Ice Surfaces

A new method to develop two-dimensional PANI nanosheets using ice as a removable hard template is presented. Distinctly high current flows of 5.5 mA at 1 V and a high electrical conductivity of 35 S cm-1 were obtained for the polyaniline (PANI) nanosheets, which marked a significant improvement from previously values on other PANIs reported over the past decades. These improved electrical properties of ice-templated PANI nanosheets were attributed to the long-range ordered edge-on π-stacking of the quinoid ring, ascribed to the ice surface-assisted vertical growth of PANI. The unprecedented advantages of the ice-templated PANI nanosheets are two-fold. First, the PANI nanosheet can be easily transferred onto various types of substrates via float-off from the ice surfaces. Second, PANI can be patterned into any shape using predetermined masks, and this is expected to facilitate the eventual convenient and inexpensive application of conducting polymers in versatile electronic device forms. A cool way to conduct: Ice is used as a removable hard template to form two-dimensional polyaniline (PANI) nanosheets. High current flows (5.5 mA at 1 V) and high electrical conductivity (35 S cm-1) were obtained for the nanosheets. The PANI nanosheet can be easily transferred onto various types of substrates from the ice surfaces, and the nanosheets can be patterned into any shape using predetermined masks. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim130281sciescopu

Synthesis and growth mechanism of carbon-supported nanoparticle catalysts by physical vapor deposition onto a liquid medium substrate

Metal nanoparticles (NPs) have been extensively investigated owing to their unique properties attributing to their high surface/bulk ratio and finite number of atoms. However, the thermodynamic instability of NPs, which originates from their finite size, limits their practical applications. Hence, carbon-supported Pt NPs are synthesized onto carbon-containing liquid substrates via direct one-step sputtering. In order to successfully produce uniform Pt NPs via sputtering using various ionic liquids as non-volatile liquid substrates, special conditions are required, and the relationship between ionic liquids and particle surfaces should be investigated. It has been reported that anions and carbon supports of ionic liquids significantly affect the dispersion and synthesis of Pt NPs. In this study, we proposed a mechanism underlying the chemical bonding between anions and carbon supports and verified it using X-ray photoelectron spectroscopy and infrared spectroscopy. © 2018 Elsevier B.V11sci

Coastal oceanographic conditions in the Prydz Bay region (East Antarctica) during the Holocene recorded in an isolation basin

Information on East Antarctic coastal environments during the Holocene is relatively sparse. This is surprising as sedimentary records from the interface between land and sea can provide chronologies of climatic change, isostatic uplift, relative sea level and the colonization of newly formed biomes. Here we examine a sediment core from Pup Lagoon, a coastal lake in the Larsemann Hills, East Antarctica. Sediment stratigraphy, fossil pigments and diatoms were used to infer the sequence of Holocene environmental and climatic change. Results show that between 5800 and 5500 cal. yr BP the marine coast of Prydz Bay was characterized by stratified, open-water conditions during spring and summer and seasonally warm conditions. From 5500 to 2750 cal. yr BP sea-ice duration in Prydz Bay increased with the coast being ice-free for 2-3 months each year, conditions which are similar to the present day. A return to stratified, open-water conditions and a reduction in winter sea-ice extent between 2750 and 2200 cal. yr BP is signalled by enhanced biogenic production and more open-water diatom taxa. This is consistent with evidence for the mid-Holocene Hypsithermal detected in other records in East Antarctica. Isostatic isolation of the Pup Lagoon basin from the sea between 2200 and 2000 cal. yr BP slightly precedes the emergence of lakes with comparable sill heights from the nearby Vestfold Hills. The colonization of Pup Lagoon after its isolation as a freshwater lake was initiated by a siliceous flora dominated by stomatocysts with microbial mat development being prevented by mechanical or physical stress. A brief period of marine incursion following the mid-Holocene Hypsithermal may be related to local events such as iceberg calving or to minor sea-level change. Weighted averaging regression, used to infer salinity in the lacustrine zone, shows that from 1500 cal. yr BP Pup Lagoon is a freshwater lake, where the flora is dominated by stratified cyanobacterial mats, with green algae and diatoms as co-dominants, comparable to modem Pup Lagoon and other lakes in the Larsemann Hills

International regulatory responses to global challenges in marine pollution and climate change

Marine pollution, also referred to as \u27pollution of the marine environment\u27, may occur as a result of different activities. Examples are land-based activities, vessel-related activitiese, dumping at sea, atmospheric and offshore hydrocarbon exploration, seabed mining, and so on. As discussed in Chapter 4, these types of marine pollution are often transboundary in nature and are harmful to human health and marine ecosystem. Similarly, climate change is a global issue involving the interests of all States. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), finalized and published in 2014, has further confirmed the existence of global warming when compared with the previous IPCC reports. It indicates that climate change has negatively affected natural and human systems on all continents and across the oceans, and asserts that 280substantial and sustained reduction of greenhouse gas (GHG) emissions would contribute to the tackling of climate change. 1 International issues need international responses. Both the marine pollution and climate change are issues with international dimensions, and thus require the global regulation by the international community