We develop a theory of monotone comparative statics for models with adjustment costs. We show that comparative-statics conclusions may be drawn under the usual ordinal complementarity assumptions on ...the objective function, assuming very little about costs: only a mild monotonicity condition is required. We use this insight to prove a general le Chatelier principle: under the ordinal complementarity assumptions, if short-run adjustment is subject to a monotone cost, then the long-run response to a shock is greater than the short-run response. We extend these results to a fully dynamic model of adjustment over time: the le Chatelier principle remains valid, and under slightly stronger assumptions, optimal adjustment follows a monotone path. We apply our results to models of saving, production, pricing, labor supply and investment.
Concerns about secondary use of data and limited opportunities for benefit-sharing have focused attention on the tension that Indigenous communities feel between (1) protecting Indigenous rights and ...interests in Indigenous data (including traditional knowledges) and (2) supporting open data, machine learning, broad data sharing, and big data initiatives. The International Indigenous Data Sovereignty Interest Group (within the Research Data Alliance) is a network of nation-state based Indigenous data sovereignty networks and individuals that developed the 'CARE Principles for Indigenous Data Governance' (Collective Benefit, Authority to Control, Responsibility, and Ethics) in consultation with Indigenous Peoples, scholars, non-profit organizations, and governments. The CARE Principles are people- and purpose-oriented, reflecting the crucial role of data in advancing innovation, governance, and self-determination among Indigenous Peoples. The Principles complement the existing data-centric approach represented in the 'FAIR Guiding Principles for scientific data management and stewardship' (Findable, Accessible, Interoperable, Reusable). The CARE Principles build upon earlier work by the Te Mana Raraunga Maori Data Sovereignty Network, US Indigenous Data Sovereignty Network, Maiam nayri Wingara Aboriginal and Torres Strait Islander Data Sovereignty Collective, and numerous Indigenous Peoples, nations, and communities. The goal is that stewards and other users of Indigenous data will 'Be FAIR and CARE.' In this first formal publication of the CARE Principles, we articulate their rationale, describe their relation to the FAIR Principles, and present examples of their application. Keywords: Indigenous, data sovereignty, data governance, data principles, FAIR principles
Developing new ABX3‐type perovskites is very important for expanding the family of perovskites and obtaining excellent light absorbing material. One strategy is replacing A site atoms with ...super‐alkali atoms for the perovskites, but super‐alkali perovskites with stable dynamics performance and high efficiency have not been found until now. Herein, massive super‐alkalis, such as Li3O, Li2F, H5O2, and so on, are introduced into the cubic CH3NH3PbI3 perovskites, and the perovskites with these super‐alkalis are systematically studied by using ab initio molecular dynamics simulation and density functional theory based first principles calculations. Calculated results indicate that the perovskites with the super‐alkalis including metal atoms show unstable dynamics performance under normal temperature and pressure. On the contrary, the first obtainable super‐alkali perovskites of cubic H5O2MBr3 (M = Ge, Sn, Pb) and H5O2PbI3 show stable dynamics performance. They also show suitable tolerance factors, negative formation energies, tunable direct band gaps, and small effective hole and electron masses. Moreover, the calculated power conversion efficiencies of 23.17% and 22.83% are obtained for the single‐junction solar cells based on the cubic H5O2SnBr3 and H5O2PbBr3 perovskites, respectively.
Introducing H5O2 cations into ABX3‐type perovskites, the cubic H5O2MBr3 (M = Ge, Sn, Pb) and H5O2PbI3 super‐alkali perovskites with suitable tolerance factors, negative formation energies, tunable direct band gaps, small carrier effective masses, stable dynamics performance and high efficiencies are obtained, which can be regarded as the excellent light absorbing materials of solar cells.
Summary
The Ga2O3 is a promising semiconductor, which is used in electric vehicles and 5G. However, the role of point defect of α‐Ga2O3 is unknown. To solve the problem, here, the influence of ...vacancy on the electronic and optical properties of α‐Ga2O3 is studied by the first‐principles calculations. Two typical vacancies, O vacancy and Ga vacancy, were designed. The calculated results show that the α‐Ga2O3 prefers to form O vacancy in comparison to the Ga vacancy. Furthermore, the calculated band gap of α‐Ga2O3 is 2.970 eV. However, the calculated band gap of O vacancy and Ga vacancy is 3.556 and 3.201 eV, which is bigger than the perfect α‐Ga2O3. Essentially, the wide band gap is that the removed atom results in a band shift from the Fermi level to the high‐energy regions. The change of band gap of these oxides is affirmed by the dielectric function. Finally, it is found that the α‐Ga2O3 oxide shows ultraviolet properties, which are in good agreement with the Ping and Berhanuddin's result. However, the calculated optical adsorption coefficient shows that the O vacancy induces the movement from the ultraviolet region to the visible light. The O vacancy and Ga vacancy weaken the storage optical properties of α‐Ga2O3 based on the analysis of loss function functional.
Mo5SiB2 is an ideal candidate for high temperature material. Although the D8l‐Mo5SiB2 has been published, the other phases and the related properties of Mo5SiB2 are still unclear. Here, two possible ...Mo5SiB2 phases (D8m‐Mo5SiB2 and Cmcm‐Mo5SiB2) are predicted by using the first principles method. The structural stability, mechanical properties, melting point and electronic structure of Mo5SiB2 are studied. The results show that the D8m‐Mo5SiB2 and Cmcm‐Mo5SiB2 are thermodynamically and dynamically stables. The calculated bulk elastic modulus, shear modulus and Young's modulus of the Cmcm‐Mo5SiB2 are close to D8l‐Mo5SiB2. In addition, the predicted Cmcm‐Mo5SiB2 has high melting point (2518.5°C) compared to the D8l‐Mo5SiB2 and D8m‐Mo5SiB2. In particular, the predicted D8m‐Mo5SiB2 exhibits better plasticity than the D8l‐Mo5SiB2. The calculated density of states and Mulliken overlap population shows that the D8m‐Mo5SiB2 and Cmcm‐Mo5SiB2 all exhibit metallic behavior. The metallic behavior mainly depends on the electronic interaction between Mo atom and B atom near Fermi level. Furthermore, the bond length of Mo‐B bond in the D8m‐Mo5SiB2 is longer than the other two structures, which may be the reason why the ductility of the former is better than the latter.
This work investigates the structural, mechanical and melting point of three Mo5SiB2 by using the first‐principles calculations. The results show that the two novel Mo5SiB2 (D8m‐Mo5SiB2 and Cmcm‐Mo5SiB2) are predicted. Three Mo5SiB2 exhibit high bulk modulus and strong elastic stiffness. In particular, these ternary silicides also show better ductility and high melting point. The calculated melting of Cmcm Mo5SiB2 is up to 2518.5°C, which is higher than the other Mo5SiB2.
The band structure, the density of states and optical absorption properties of Cu-doped ZnO were studied by the first-principles generalized gradient approximation plane-wave pseudopotential method ...based on density functional theory. For the Zn
Cu
O (
= 0,
= 0.0278,
= 0.0417) original structure, geometric optimization and energy calculations were performed and compared with experimental results. With increasing Cu concentration, the band gap of the Zn₁
Cu
O decreased due to the shift of the conduction band. Since the impurity level was introduced after Cu doping, the conduction band was moved downwards. Additionally, it was shown that the insertion of a Cu atom leads to a red shift of the optical absorption edge, which was consistent with the experimental results.
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