Im pro per3/15/2023 Relatively high pyroelectric FOMs have been demonstrated in improper ferroelectric dicalcium-lead-propionate and iron-iodine-boracite stemming from their relatively low dielectric constant of 4 to 13 ( 16). The low dielectric constant of improper ferroelectrics is thus conducive to large pyroelectric FOMs. In improper ferroelectrics, the dielectric constant remains low even close to the phase transition temperature, which is usually more than one to two orders of magnitude lower than those of proper ones ( 4, 9, 15). Contrary to proper ferroelectric whose primary order parameter is polarization, the polarization of improper ferroelectric is a secondary order parameter that develops following the primary order parameter ( 12– 14). The unique characteristics of improper ferroelectricity offer the potential for overcoming this fundamental limitation ( 11). Therefore, to achieve high pyroelectric FOMs and factors, it necessitates that pyroelectric materials have simultaneously a high pyroelectric coefficient and a low dielectric constant. For pyroelectric energy harvesting, the FOMs are F E = p 2/(ε 0ε r) and F EN = p 2 T h/(ε 0ε r c V) (also termed as the electrothermal coupling factor k 2, where T h is the maximum temperature in the thermal cycle), which represent the amount and efficiency of electric power converted from a given thermal energy input, respectively ( 1, 6– 8). F V denotes the maximum pyroelectric voltage for a given energy input, while F D characterizes the ability of detectors to sense weak signals that compete with noises. For example, for pyroelectric sensors, the FOMs are voltage responsivity F V = p/(ε 0ε r c V) and detectivity F D = p/, where ε 0, ε r, c V, and tanδ are the vacuum permittivity, dielectric constant, volumetric heat capacity, and loss tangent, respectively ( 1, 6). Several figures of merit (FOMs) have been formulated for pyroelectric materials to evaluate their relative potentials for a number of different applications. Along with the facile preparation and self-poling features, the improper molecular ferroelectrics hold great promise for high-performance pyroelectric devices. Our first-principles and thermodynamic calculations show that the strong coupling between the order parameters, i.e., the rotation angle of anions and polarization, is responsible for the colossal pyroelectric coefficient of the molecular ferroelectrics. Concurrently, the improper molecular ferroelectrics have pyroelectric coefficients that are more than one order of magnitude greater than the state-of-the-art pyroelectric Pb(Mg 1/3Nb 2/3)O 3-PbTiO 3. Here, we report the molecular ferroelectric ClO 4 and BF 4 (dabco = diazabicyclooctane) exhibiting improper ferroelectric behavior and pyroelectric FOMs outperforming the current ferroelectrics. Throughout Improper Life, Campbell insists that biopolitics can become more positive and productively asserts an affirmative technē not thought through thanatos but rather practiced through bíos.Although ferroelectric materials exhibit large pyroelectric coefficients, their pyroelectric figures of merit (FOMs) are severely limited by their high dielectric constants because of the inverse relationship between FOMs and dielectric constant. But in Improper Life he articulates a corrective biopolitics that can begin with rereadings of Foucault (especially his late work regarding the care and technologies of the self), Freud (notably his writings on the drives and negation), and Gilles Deleuze (particularly in the relation of attention to aesthetics). In fact, Campbell shows how all of these philosophers have pointed toward a tragic, thanatopolitical destination as somehow an inevitable result of technology. Campbell’s dexterous inquiry-as-intervention.Ĭampbell argues that a “crypto-thanatopolitics” can be teased out of Heidegger’s critique of technology and that some of the leading scholars of biopolitics-including Michel Foucault, Giorgio Agamben, and Peter Sloterdijk-have been substantively influenced by Heidegger’s thought, particularly his reading of proper and improper writing. Has biopolitics actually become thanatopolitics, a field of study obsessed with death? Is there something about the nature of biopolitical thought today that makes it impossible to deploy affirmatively? If this is true, what can life-minded thinkers put forward as the merits of biopolitical reflection? These questions drive Improper Life, Timothy C.
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