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Excitonic coupling, electronic coupling, and cooperative interactions in self-assembled lead halide perovskite nanocrystals were reported to give rise to a red-shifted collective emission peak with accelerated dynamics. Here we report that similar spectroscopic features could appear as a result of the nanocrystal reactivity within the self-assembled superlattices. This is demonstrated by studying CsPbBr3 nanocrystal superlattices over time with room-temperature and cryogenic micro-photoluminescence spectroscopy, X-ray diffraction, and electron microscopy. It is shown that a gradual contraction of the superlattices and subsequent coalescence of the nanocrystals occurs over several days of keeping such structures under vacuum. As a result, a narrow, low-energy emission peak is observed at 4 K with a concomitant shortening of the photoluminescence lifetime due to the energy transfer between nanocrystals. When exposed to air, self-assembled CsPbBr3 nanocrystals develop bulk-like CsPbBr3 particles on top of the superlattices. At 4 K, these particles produce a distribution of narrow, low-energy emission peaks with short lifetimes and excitation fluence-dependent, oscillatory decays. Overall, the aging of CsPbBr3 nanocrystal assemblies dramatically alters their emission properties and that should not be overlooked when studying collective optoelectronic phenomena nor confused with superfluorescence effects. ; The work of D.B. was supported by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 794560 (RETAIN). R.X.Y. and L.Z.T. were supported by the Molecular Foundry, a DOE Office of Science User Facility of the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. D.S. acknowledges support from the project PRIN Interacting Photons in Polariton Circuits—INPhoPOL (Ministry of University and Scientific Research, MIUR, 2017P9FJBS_001). We thank P. Cazzato, L. De Marco, D. Ballarini, D. G. Suárez-Forero, V. Ardizzone, L. ...

Physiology of Insect Cold Hardiness -- 1. A Tribute to R. W. Salt -- 2. Principles of Insect Low Temperature Tolerance -- 3. The Water Relations of Overwintering Insects -- 4. Biochemistry of Cryoprotectants -- 5. Hemolymph Proteins Involved in Insect Subzero-Temperature Tolerance: Ice Nucleators and Antifreeze Proteins -- Impact on Development and Survival -- 6. Cold Shock and Heat Shock -- 7. Effects of Cold on Morphogenesis -- 8. Relationship between Cold Hardiness and Diapause -- 9. Thermoperiodism -- Species Adaptations -- 10. Winter Habitats and Ecological Adaptations for Winter Survival -- 11. Freezing Tolerance in the Goldenrod Gall Fly (Eurosta solidaginis) -- 12. Behavioral and Physiological Adaptations to Cold in a Freeze-Tolerant Arctic Insect -- 13. Comparative Invertebrate Cold Hardiness -- 14. Adaptations to Alpine and Polar Environments in Insects and Other Terrestrial Arthropods -- 15. Overwintering of Freshwater Benthic Macroinvertebrates -- Practical Applications -- 16. Cryopreservation of Insect Germplasm: Cells, Tissues, and Organisms -- 17. Cryobiology of Drosophila melanogaster Embryos -- 18. Silkworm Eggs at Low Temperatures: Implications for Sericulture -- 19. Overwintering in Honey Bees: Implications for Apiculture -- 20. Implications of Cold Hardiness for Pest Management -- Taxonomic Index -- Contributors.

"Report No. K-1225 ; File No.: S-214; RES 1756; Subject Category: Instrumentation." ; "July 22, 1955." ; Includes bibliographical references (leaf 12). ; K-25 Plant, Carbide and Carbon Chemicals Company, a division of Union Carbide and Carbon Corporation acting under U.S. Government Contract ; Mode of access: Internet.

1 Elementary Concepts of Specific Heats -- 1.1. Definitions -- 1.2. Thermodynamics of Simple Systems -- 1.3. Difference Between Cp and Cv -- 1.4. Variation of Specific Heats with Temperature and Pressure -- 1.5. Statistical Calculation of Specific Heats -- 1.6. Different Modes of Thermal Energy -- 1.7. Calorimetry -- 2 Lattice Heat Capacity -- 2.1. Dulong and Petit's Law -- 2.2. Equipartition Law -- 2.3. Quantum Theory of Specific Heats -- 2.4. Einstein's Model -- 2.5. Debye's Model -- 2.6. Comparison of Debye's Theory with Experiments -- 2.7. Shortcomings of the Debye Model -- 2.8. The Born-Von Kármán Model -- 2.9. Calculation of g(v) -- 2.10. Comparison of Lattice Theory with Experiments -- 2.11. Debye ? in Other Properties of Solids -- 3 Electronic Specific Heat -- 3.1. Specific Heat of Metals -- 3.2. Quantum Statistics of an Electron Gas -- 3.3. Specific Heat of Electrons in Metals -- 3.4. Electronic Specific Heat at Low Temperatures -- 3.5. Specific Heat and Band Structure of Metals -- 3.6. Specific Heat of Alloys -- 3.7. Specific Heat of Semiconductors -- 3.8. Phenomenon of Superconductivity -- 3.9. Specific Heat of Superconductors -- 3.10. Recent Studies -- 4 Magnetic Contribution to Specific Heats -- 4.1. Thermodynamics of Magnetic Materials -- 4.2. Types of Magnetic Behavior -- 4.3. Spin Waves—Magnons -- 4.4. Spin Wave Specific Heats -- 4.5. The Weiss Model for Magnetic Ordering -- 4.6. The Heisenberg and Ising Models -- 4.7. Specific Heats Near the Transition Temperature -- 4.8. Paramagnetic Relaxation -- 4.9. Schottky Effect -- 4.10. Specific Heat of Paramagnetic Salts -- 4.11. Nuclear Schottky Effects -- 5 Heat Capacity of Liquids -- 5.1. Nature of the Liquid State -- 5.2. Specific Heat of Ordinary Liquids and Liquid Mixtures -- 5.3. Liquid 4He at Low Temperatures -- 5.4. Phonon and Roton Specific Heats -- 5.5. Transition in Liquid 4He -- 5.6. Specific Heat of Liquid 3He -- 5.7. Liquid 3He as a Fermi Liquid -- 5.8. Mixtures of 4He and 3He -- 5.9. Supercooled Liquids—Glasses -- 6 Specific Heats of Gases -- 6.1. Cp and Cv of a Gas -- 6.2. Classical Theory of Cv of Gases -- 6.3. Quantum Theory of Cv of Gases -- 6.4. Rotational Partition Function -- 6.5. Homonuclear Molecules—Isotopes of Hydrogen -- 6.6. Vibrational and Electronic Specific Heats -- 6.7. Calorimetric and Statistical Entropies—Disorder in Solid State -- 6.8. Hindered Rotation -- 6.9. Entropy of Hydrogen -- 7 Specific-Heat Anomalies -- 7.1. Spurious and Genuine Anomalies -- 7.2. Cooperative and Noncooperative Anomalies -- 7.3. Order-Disorder Transitions -- 7.4. Onset of Molecular Rotation -- 7.5. Ferroelectricity -- 7.6. Transitions in Rare-Earth Metals -- 7.7. Liquid-Gas Critical Points -- 7.8. Models of Cooperative Transitions -- 8 Miscellaneous Problems in Specific Heats -- 8.1. Specific Heat Near Phase Transitions -- 8.2. Specific Heat at Saturated Vapor Pressure -- 8.3. Relaxation of Rotational and Vibrational Specific Heats -- 8.4. Defects in Solids -- 8.5. Surface Effects -- 8.6. Compilations of Specific-Heat Data -- 8.7. Tabulations of Specific-Heat Functions -- Appendix (Six-Figure Tables of Einstein and Debye Internal-Energy and Specific-Heat Functions) -- Author Index.

The European Union has adopted a plan to decrease 20 % of total energy consumption through improved energy efficiency by 2020. One way of achieving this challenging goal may be to use efficient water-based heating systems supplied by heat pumps or othersustainable systems. The goal of this research was to analyze and improve the thermalperformance of water-based baseboard heaters at low-temperature water supply. Both numerical (CFD) and analytical simulations were used to investigate the heat efficiency of the system. An additional objective of this work was to ensure that the indoor thermal comfort was satisfied in spaces served by such a low-temperature heating system. Analyses showed that it was fully possible to cover both transmission and ventilation heatl osses using baseboard heaters supplied by 45 °C water flow. The conventional baseboards, however, showed problems in suppressing the cold air down-flow created by 2.0 m high glazing and an outdoor temperature of – 12 °C. The draught discomfort at ankle level was slightly above the upper limit recommended by international and national standards. On the other hand, thermal baseboards with integrated ventilation air supply showed better ability to neutralize cold downdraught at the same height and conditions. Calculations also showed that the heat output from the integrated system with one ventilation inlet was approximately twiceas high as that of the conventional one. The general conclusion from this work was that low-temperature baseboards, especially with integrated ventilation air supply, are an efficient heating system and able to be combined with devices that utilize the low-quality sustainable energy sources such as heat pumps. ; QC 20101029

Room temperature photoluminescence (PL) is a powerful technique to study the properties of semiconductors. However, the interpretation of the data can be cumbersome when non-ideal band edge absorption takes place, as is the case in the presence of potential fluctuations. In this study, PL measurements are modeled to quantify potential fluctuations in Cu ( In , Ga ) Se 2 (CIGS) absorber layers for photovoltaic applications. Previous models have attributed these variations to either bandgap fluctuations (BGFs) or electrostatic fluctuations (EFs). In reality, these two phenomena happen simultaneously and, therefore, affect the PL together. For this, the unified potential fluctuation (UPF) model is introduced. This model incorporates the effect of both types of fluctuations on the absorptance of the material and subsequently the PL spectra. The UPF model is successfully used to fit both single- and three-stage co-evaporated ultrathin (around 500 nm) CIGS samples, showing a clear improvement with respect to the previous BGF and EF models. Some PL measurements show possible interference distortions for which an interference function is used to simultaneously correct the PL spectra of a sample measured with several laser excitation intensities. All the models used in this work are bundled into a user-friendly, open-source Python program.& nbsp;Published under an exclusive license by AIP Publishing ; Dr. J. de Wild and Professor B. Vermang received funding from the European Union's H2020 research and innovation programme under Grant Agreement No. 715027 for this work.

Presented here are authoritative and up-to-date assessments of the homogenous and heterogenous chemical and physical processes occuring in the troposphere and stratosphere, especially during the "ozone hole" event. The book begins with an overview of atmospheric chemistry, followed by reviews of relevant homogenous reactions in the gas phase and the microphysics and physical chemistry of heterogenous processes that occur on, or in aerosols, rain and ice. Low temperature laboratory studies are compared with related fieldwork measurements, particularly in relation to the formation and composition of polar stratospheric clouds. Also discussed are measurements in glacial ice. Finally chemical modelling of the troposphere and stratosphere, including heterogenous processes, is reviewed