Different contents of SrAl 2 O 4 :Eu,Dy, one of the long afterglow phosphorescent materials with high brightness, were melt-mixed with low-density polyethylene (LDPE) and Polymethyl methacrylate (PMMA) polymers, respectively. The morphology and composition of the samples were observed by means of a scanning electron microscope (SEM) coupled with an energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), and transmission electron microscope (TEM). Sharp and broad X-ray diffraction (XRD) peaks were observed for the LDPE and the PMMA composites respectively, reflecting configuration characteristics similar to those of the respective pure polymers. TEM micrographs show a transition from nanosized particles to cluster formation with increase in phosphor concentration. The green long-lasting phosphorescence of the composites was observed in the dark after removal of the excitation light. Photoluminescence (PL) was observed in the composites of both polymers for phosphor volume concentrations above 1.0% for PMMA and above 0.5% for LDPE. For each of these samples, a broad PL peak at about 505 nm wavelength was observed after excitation at 350 nm with a xenon lamp. For the LDPE composites, the DSC results show that the presence of the phosphor in the polymer has no major influence on either the melting temperature or enthalpy values of the polymer.
The idea of a separate (dyadic) peace among (liberal) democracies remains an alluring proposition for Western intellectuals and policy makers, despite criticism from non-Western circles. We contend that explanations of the democratic peace have degenerated into theoretical stalemate, with the structuralist bias depicted in (neo)realist theories and, conversely, the individualist nature of liberal theories of the democratic peace, providing little room for alternative conceptions. As a distinct theory of foreign policy in which the relationship between agents and structures, and their intersection across differing levels of analysis, is more fully explored, neoclassical realism could hold potential for transcending the explanatory dichotomies plaguing the theorisation of the democratic peace. Moreover, it could open up room for an alternative theoretical framework for theorising the dyadic peace and its implications for how peace-building initiatives are approached.
It is widely accepted today that hypersonic weapons pose insurmountable challenges to nuclear deterrence. Although speed has always been a critical factor in warfare, the development of hypersonics provides unprecedented advantages in terms of the speed and agility of missiles. The increase in the speed and agility of hypersonic missiles drastically reduces the response time of nuclear states, encouraging the pre-emptive use of force. Two arguments inform the latter claim. The first holds that the speed and agility of hypersonic missiles are likely to render existing and future missile defences obsolete. The second contends that the failure of missile defences coupled with the reduction of the response time of nuclear states encourages the pre-emptive use of force. Where nuclear states are unable to field survivable second-strike forces, the stability of nuclear deterrence becomes highly problematic. Besides these arguments, the dual-use nature of hypersonic weapons ostensibly increases the risk of nuclear escalation. Against this bleak assessment, in this article, the author questions the destabilising effects of hypersonic weapons on deterrence stability, arguing that nuclear deterrence is -and is likely to remain -deeply stable. A thoroughgoing consideration of the strategic implications of nuclear weapons provides optimism about the stability of nuclear deterrence in the face of the development of hypersonic weapons. Two arguments are advanced in support of the continuing stability of nuclear deterrence. First, missile defences have (and are likely to remain) inefficacious, with the development of hypersonic weapons merely reinforcing (rather than establishing) this fact. Second, a would-be aggressor contemplating the pre-emptive use of force would have to believe that it could destroy all of an adversary's nuclear force before any can be launched.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.