Is China-Japan Relations Envisaging a Phase of Détente?

The recent course of events suggests an upswing in the diplomatic equation shared between China and Japan. The frosty relationship seems to be experiencing ‘new warmth’ after a hiatus of tensions over historical issues and territorial dispute in the East China Sea. The ongoing reciprocity can be gauged from the change in their respective attitude towards the other. Most significantly, the sign of progress was witnessed at the 40 minutes long meeting between Chinese President Xi Jinping and Japanese Prime Minister Shinzo Abe on the sidelines of the G20 Summit at Hamburg, Germany. This marked the first one-on-one meeting between the two leaders amidst growing tensions in the East China Sea, after an interregnum since a brief meeting on the sidelines of the 2016 APEC Summit. Thereby, the Xi-Abe meeting at G20 is not just symbolic but also significant

Effects of Surfactants on the Thermal and Fire Properties of Poly(Methyl Methacrylate)/Clay Nanocomposites

Nanocomposites of poly(methyl methacrylate) (PMMA) with layered silicates and with polyhedral oligosilsesquioxanes (POSS) were prepared by bulk polymerization. The thermal and fire stabilities of the various organically-modified clay and POSS nanocomposites were evaluated using both thermogravimetric analysis (TGA) and cone calorimetry. Thermogravimetric analysis is not a good criteria for evaluating nanocomposite formation but cone calorimetry can be. For montmorillonite systems, when more than 4% clay is present, the expected reduction in peak heat release rate is observed. For hectorite, a minimum of 6% clay concentration is required to achieve the same reduction in peak heat release rate. POSS has the potential to reduce the peak heat release rate but one must be careful in selecting the POSS material to be evaluated

Effect of plate roughness on the field near RPC plates

The inner surfaces of the electrodes encompassing the gas volume of a Resistive Plate Chamber (RPC) have been found to exhibit asperities with, grossly, three kinds of features. The desired uniform electric field within the gas volume of RPC is expected to be affected due to the presence of these asperities, which will eventually affect the final response from the detector. In this work, an attempt has been made to model the highly complex roughness of the electrode surfaces and compute its effect on the electrostatic field within RPC gas chamber. The calculations have been performed numerically using Finite Element Method (FEM) and Boundary Element Method (BEM) and the two methods have been compared in this context.Comment: 7 pages, 12 figures, 1 tabl

Fire Retardancy of Vinyl Ester Nanocomposites: Synergy with Phosphorus-Based Fire Retardants

Vinyl ester (PVE) nanocomposites were prepared using both clay and polyhedral oligosilsesquioxanes (POSS) as the nano-dimensional material. From cone calorimetric data, it was shown that both POSS and clay affect the flammability of the nanocomposites to the same extent. To improve on the flame retardancy, the nanocomposites were combined with phosphorous-containing fire retardants (FRs) and the result compared to the benchmark halogen-containing system. The use of the cone calorimeter to investigate the fire properties of these nanocomposites showed a great reduction in peak heat release rate (PHRR) in the presence of phosphate and slight improvements in average mass loss rate (AMLR) while thermogravimetric analysis showed improvement in char yield in the presence of phosphate. Several different organically modified clays were used and they affected the flammability to different extents. The time that the resin and clay were mixed and the atmosphere in which the reaction was carried out do not have an effect on the flammability and thermal stability of the nanocomposites. The effect of curing temperature on the clay dispersion and flammability was also investigated

Synergy Between Nanocomposite Formation and Low Levels of Bromine on Fire Retardancy in Polystyrenes

An organically-modified clay has been prepared using ammonium salts which contain an oligomeric material consisting of vinylbenzyl chloride, styrene and dibromostyrene. The presence of dibromostyrene enhances the flame retardancy of polystyrene nanocomposites compared to both the virgin polymer and polystyrene nanocomposites prepared from non-halogen-containing organically-modified clays. The nanocomposites were prepared both by bulk polymerization and melt blending and they were evaluated by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and cone calorimetry measurements. Bulk polymerization produced nanocomposites with reduced peak heat release rate, reduced total heat release and improved thermal stability. It is noteworthy that all these improvements were obtained with clay loading as low as 3% and bromine content less than 4%

Photoluminescence Studies of Polytype Heterostructured InP Nanostructures

The interface between two semiconductors significantly influences their optical and electronic properties. In contrast to traditional material heterostructures, polytype heterostructures between wurtzite (wz) and zincblende (zb) segments in homomaterial InP nanostructures exhibit sharp interfaces with minimal strain. The wz/zb interface of heterostructured InP has a type-II band alignment, which results in the accumulation of charge carriers on either side of the interface, electrons on one side and holes on the other side. This separation leads to the formation of spatially separated (indirect) excitons (IXs) at the interface. This thesis focuses on studying the spatial and temporal recombination characteristics of IXs in these polytypic heterostructures in InP nanostructures. Two types of nanostructures, nanowires (NWs) and platelets, are employed to investigate single type-II wz/zb interfaces. NWs have cylindrical or hexagonal cross-sections with a very small diameter and longer length, resulting in a small interface crosssection ( 500 mm2).The methodology in this thesis utilizes non-invasive optical techniques, specifically steady-state (SS) and time-resolved (TR) photoluminescence (PL) to analyze the emission spectra of InP polytype heterostructures. The confirmation of a type-II band alignment is established through excitation power density (EPD)-dependent SSPL, where the IX emission redshifts with reduced EPD. In addition, the TRPL data reveals a long lived and non-exponential decay profile of the IX emission.Paper-I delves into the recombination dynamics of IXs at the single wz/zb interface in InP NWs. Overcoming the small cross-section limitation of NWs, platelets, with a substantially larger cross-section, provide a larger sample area and, thus, provides access to investigating the transport of IXs. Paper-II and Paper-III explore the IX dynamics at the wz/zb single-interface of platelets. Spatially resolved SSPL in undoped platelets unveils EPD-dependent transport of IXs at the type-II interface. The broad spatial distribution of the IX emission suggests repulsive-force-driven transport at high EPD, while the narrow spatial distribution at low EPD indicates a diffusive transport mechanism. The temporal evolution, observed through spatially resolved TRPL, depicts an initial rapid expansion of the IXs driven by Coulomb repulsion - a result of the dipole alignment of the IXs at the interface. After this initial step, it is transitioning to a linear expansion indicative of diffusive-driven transport in undoped platelets. This behavior is characteristic for a low scattering of IXs which is indicative of a minor impact of interface fluctuations caused by the polytype interface in our system.Beyond characterizing undoped nanostructures, our research explores the impact of a two-dimensional electron gas (2DEG) on the recombination and spatial dynamics of IXs for n-type doped nanostructures. These doped structures maintain the same geometry as the undoped counterparts, except for the n-type doping applied to the entire wz segment. Doped samples exhibit a smaller redshift with reduced EPD and shorter recombination times for IX emission compared to the undoped ones. Additionally, the spatial distribution of IX emission is independent of EPD