The adaptation of death-feigning (thanatosis), a subject that has been overlooked in evolutionary biology, was inferred in a model prey-and-predator system. We studied phenotypic variation among individuals, fitness differences, and the inheritance of death-feigning behaviour in the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Two-way artificial selections for the duration of death-feigning, over 10 generations, showed a clear direct response in the trait and a correlated response in the frequency of death-feigning, thus indicating variation and inheritance of death-feigning behaviour. A comparison of the two selected strains with divergent frequencies of death-feigning showed a significant difference in the fitness for survival when a model predator, a female Adanson jumper spider, Hasarius adansoni Audouin (Araneomophae: Salticidae), was presented to the beetles. The frequency of predation was lower among beetles from strains selected for long-duration than among those for short-duration death-feigning. The results indicate the possibility of the evolution of death-feigning under natural selection.

LiFeO2­Li2MnO3 solid solution was synthesized using solid-state reaction and hydrothermal-postannealing methods and characterized as a positive electrode material for rechargeable lithium batteries. Although the maximum Fe content false[normalFe/false(normalFe+normalMnfalse)false] was limited up to 30% by solid-state reaction, the content can extend up to 75% by the hydrothermal-postannealing method. Neutron and X-ray Rietveld analysis reveal that the basic structure of the sample is a layered rock-salt structure isostructural with LiCoO2 false(R3¯mfalse) in which Fe ions exist on both Li (3a) and Co (3b) sites. Elemental analysis and 57normalFe Mössbauer spectra show Fe ions exist as 3+/4+ mixed-valence state after the samples were postannealed above 650°C. The initial charge capacity of Li/sample cells was above 100 mAh/g when the upper voltage limit was 4.3 V. The plateau around 4 V was observed for all Li/sample cells on first discharge. The maximum of initial discharge capacity was about 100 mAh/g down to 2.5 V for the Li/(50% Fe-substituted sample) cell, when the positive electrode was obtained by postannealing at 650°C in air. The capacity fading of the 4 V plateau could be suppressed by adjusting the Fe content to less than 50%, postannealing temperature between 600 and 700°C, and by 10% Ni substitution. © 2002 The Electrochemical Society. All rights reserved.

Li 4/3 Ti 2/3 O 2 -LiFeO 2 solid solution, Li (4 2 x)/3 Ti (2 2 2x)/3 Fe x O 2 (0.18 ¡ x ¡ 0.67), which has the cubic rock-salt structure (Fm3 ¯m, average particle size less than 100 nm), was synthesized from Fe-Ti co-precipitates by hydrothermal reaction with excess LiOH and KClO 3 at 220 uC. Calcination of the products with lithium hydroxide in an oxidative atmosphere leads to the oxidation of trivalent iron to a 31/41 mixed valence state. Hydrothermally-obtained Li 1.2 Ti 0.4 Fe 0.4 O 2 gave maximum initial charge (266 mA h g 21 ) and discharge capacities (153 mA h g 21 around 3 V) between 2.5 and 4.8 V. Calcination enabled us not only to improve the crystallinity, but also suppress the discharge capacity fading with cycle number. Two plateaus around 3 and 4 V were observed on discharging by decreasing the amount of Li extraction (0.4 Li per chemical formula). Although the cubic rock-salt structure was retained during both charge and discharge processes, a partial 3d-cation displacement from octahedral 4a to tetrahedral 8c sites and some oxygen loss were observed after electrochemical delithiation. In-situ 57 Fe Mo ¨ssbauer spectroscopy showed evidence of the Fe 31 /Fe 41 redox only around the 4 V region.

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By combining coprecipitation, hydrothermal, and firing methods under various firing temperatures (500−750 °C), Fe-substituted Li2MnO3 (nominal formula Li1.2Fe0.4Mn0.4O2) samples were prepared. A pure O3 phase was obtained below 700 °C. However, a small amount of spinel ferrite-like LiFe5O8 coexisted as an impurity phase for the sample that was fired at 750 °C. The maximum initial and 10th discharge capacities were obtained at 600−650 °C because of the balance between the development of 3d cation ordering, their primary particle size, and Li content, depending on the iron valence, which is changeable between 3+ and 4+.