Refraction of Flexural Waves by Ultra-broadband Achromatic Meta-slab with Wavelength-dependent Phase Shifts

Great progress has been made in modulating flexural waves by elastic metasurfaces. Most of the proposed elastic metasurfaces suffer from chromatic aberration, limited in a narrow bandwidth around the designed frequency. In this paper, overcoming the chromatic aberration, an ultra-broadband achromatic meta-slab (UAM) with subunits of gradient thickness is proposed to realize the refraction angle unchanged with the incident frequency. Based on the phase compensation principle, wavelength-dependent phase shifts for the UAM that realize achromaticity are obtained. In order to verify the effectiveness of the theoretical design, the transmitted wavefields are solved according to the phased array theory, and the results correspond with those obtained by the finite element (FE) simulations and experiments, which show that the refraction angle is unchanged for incident frequencies from 2 kHz to 8 kHz. Besides, the UAM is extended into a periodic meta-slab, and multifrequency achromaticity is realized. Our designed meta-slabs overcome the chromatic aberration by simple configurations, which have significance in the applications of vibration control, vibrational energy harvesting, and health monitoring.

Influence of Drift on Robot Repeatability and Its Compensation

This paper presents an approach to compensate for the effect of thermal expansion on the structure of an industrial robot and thus to reduce the repeatability difference of the robot in cold and warm conditions. In contrast to previous research in this area that deals with absolute accuracy, this article is focused on determining achievable repeatability. To unify and to increase the robot repeatability, the measurements with highly accurate sensors were performed under different conditions on an industrial robot ABB IRB1200, which was equipped with thermal sensors, mounted on a pre-defined position around joints. The performed measurements allowed to implement a temperature-based prediction model of the end effector positioning error. Subsequent tests have shown that the implemented model used for the error compensation proved to be highly effective. Using the methodology presented in this article, the impact of drift can be reduced by up to 89.9%. A robot upgraded with a compensation principle described in this article does not have to be warmed up as it works with the same low repeatability error in the entire range of the achievable temperatures.

Calculation of the contribution to muon g − 2 due to the effective anomalous three boson interaction and the new experimental result

Using the approach based on Bogoliubov compensation principle is applied to the calculation of a contribution to the muon [Formula: see text]. Using the previous results on spontaneous generation of the effective anomalous three-boson interaction we calculate the contribution, which proves to agree with the well-known discrepancy. The calculated quantity contains no adjusting parameters but the experimental values for the muon and the [Formula: see text]-boson masses. The result can be considered as a confirmation of the approach.

Just Social Risk Imposition and the Demand for Fair Risk Sharing

Existing accounts of social insurance tend to treat social risks as given and ask whether it is justified for the state to deal with these risks for its citizens. They ignore that many common risks are in fact imposed on citizens as a byproduct of the institutional choices of the society, which call for justification in the first place. In this paper, I use the Scanlonian contractualist framework to develop an account of just social risk imposition which implies a demand for fair risk sharing by all members of a society. In particular, I defend a compensation principle which requires that compensation be paid to victims of risk materialisation. This duty of paying should be shared by all those who benefit from the imposition of the relevant risk. I suggest that this provides a case for social insurance as a way of fairly sharing the burden of social risks.

Urban-Rural Inequality of Opportunity in Health Care: Evidence from China

(1) Background: We aim to measure the urban-rural inequality of opportunity in healthcare in China based on the theory of Equality of Opportunity (EOp). (2) Methods: Following the compensation principle, we establish a decomposition strategy for the fairness gap, which we use for the measurement of the inequality of opportunity in urban-rural healthcare utilization. We then use China Health and Nutrition Survey (CHNS) data from 1997 to 2006 to calculate the fairness gap. (3) Results: Empirical analysis using CHNS data shows that the ratio of the fairness gap to the directly observed average urban-rural difference in healthcare was 1.167 for 1997–2000 and 1.744 for 2004–2006. The average urban-rural difference observed directly from original statistical data may have underestimated the degree of this essential inequity. (4) Conclusions: Our findings suggest that upgrading urban-rural reimbursement ratios may not be sufficient in eliminating the inequality of opportunity in healthcare utilization between urban and rural residents. Within the context of an urban-rural dualistic social structure and widening of the urban-rural income gap, a shift to a pro-disadvantaged policy will be a more effective approach in promoting equality of opportunity in healthcare.

Part I Fundamentals, 2 Principles

In this chapter six major principles are identified: freedom of contract; objectivity; the contractual bond principle (‘pacta sunt servanda’); estoppel; good faith and fair dealing; the compensation principle. The nature of each principle is explained and its operation within the law is illustrated and amplified. The first three of these principles are well-established, but it is of particular interest that the good faith principle is recognized here. The principle is manifested in various ways, which are identified. The estoppel principle is a long-standing but complex feature of English private law and its various forms are here explained. The compensation principle encapsulates the complex rules governing the award of damages for breach of contract. The aim of contractual damages is not to punish, nor to over-compensate, or award double compensation. The paradigm award of contractual damages is to place the innocent party in the position which would have existed if there had not been a breach.

Contract Law in Practice

This book is a detailed examination of the general doctrines of English law of contract. Cases are analysed precisely, providing quick access to the major authoritative passages in the leading judgments. The coverage is comprehensive. It focuses on English law, but it also provides analysis of assistance throughout the Common Law family of legal systems. It provides up-to-date examination of case law developments. There are nearly fifty ‘evaluation’ sections which provide comment on controversial or unclear topics. Six major principles are identified: Freedom of Contract; Objectivity; the Contractual Bond Principle; Estoppel; Good Faith and Fair Dealing; the Compensation Principle.

Special Concern and Personal Identity

As discussed by John Locke, Joseph Butler, and Thomas Reid, prudence involves a special concern for the agent’s own personal good that she does not have for others. This should be a concern for the agent’s overall good that is temporally neutral and involves an equal concern for all parts of her life. In this way, prudence involves a combination of agent relativity and temporal neutrality. This asymmetrical treatment of matters of interpersonal and intertemporal distribution might seem arbitrary. Henry Sidgwick raised this worry, and Thomas Nagel and Derek Parfit have endorsed it as reflecting the instability of prudence and related doctrines such as egoism and the self-interest theory. However, Sidgwick thought that the worry was unanswerable only for skeptics about personal identity, such as David Hume. Sidgwick thought that one could defend prudence by appeal to realism about personal identity and a compensation principle. This is one way in which special concern and prudence presuppose personal identity. However, as Jennifer Whiting has argued, special concern displayed in positive affective regard for one’s future and personal planning and investment is arguably partly constitutive of personal identity, at least on a plausible psychological reductionist conception of personal identity. After explaining both conceptions of the relation between special concern and personal identity, the chapter concludes by exploring what might seem to be the paradoxical character of conjoining them, suggesting that there may be no explanatory priority between the concepts of special concern and personal identity.

Development of the Soft X-ray AGM–AGS RIXS beamline at the Taiwan Photon Source

We report on the development of a high-resolution and highly efficient beamline for soft X-ray resonant inelastic X-ray scattering (RIXS) located at the Taiwan Photon Source. This beamline adopts an optical design that uses an active grating monochromator (AGM) and an active grating spectrometer (AGS) to implement the energy compensation principle of grating dispersion. Active gratings are utilized to diminish defocus, coma and higher-order aberrations, as well as to decrease the slope errors caused by thermal deformation and optical polishing. The AGS is mounted on a rotatable granite platform to enable momentum-resolved RIXS measurements with scattering angles over a wide range. Several high-precision instruments developed in-house for this beamline are described briefly. The best energy resolution obtained from this AGM–AGS beamline was 12.4 meV at 530 eV, achieving a resolving power of 4.2 × 104, while the bandwidth of the incident soft X-rays was kept at 0.5 eV. To demonstrate the scientific impact of high-resolution RIXS, we present an example of momentum-resolved RIXS measurements on a high-temperature superconducting cuprate, i.e. La2–x Sr x CuO4. The measurements reveal the A1g buckling phonons in superconducting cuprates, opening a new opportunity to investigate the coupling between these phonons and charge-density waves.