Revealing the low thermal conductivity of high-entropy rare-earth tantalates via multi-scale defect analysis

Thermal barrier coating(TBC)materials can improve energy conversion efficiency and reduce fossil fuel use.Herein,novel rare earth tantalates RETaO_(4),as promising candidates for TBCs,were reassembled into multi-component solid solutions with a monoclinic structure to further depress thermal conductivity via an entropy strategy.The formation mechanisms of oxygen vacancy defects,dislocations,and ferroelastic domains associated with the thermal conductivity are demonstrated by aberration-corrected scanning transmission electron microscopy.Compared to single-RE RETaO_(4)and 8YSZ,the intrinsic thermal conductivity of(5RE1/5)TaO4 was decreased by 35%–47%and 57%–69%at 1200℃,respectively,which is likely attributed to multi-scale phonon scattering from Umklapp phonon–phonon,point defects,domain structures,and dislocations.r¯3+RE/r5+Ta and low-temperature thermal conductivity are negatively correlated,as are the ratio of elastic modulus to thermal conductivity(E/κ)and high-temperature thermal conductivity.Meanwhile,the high defects’concentration and lattice distortion in high-entropy ceramics enhance the scattering of transverse-wave phonons and reduce the transverse-wave sound velocity,leading to a decrease in the thermal conductivity and Young’s modulus.In addition,5HEC-1 has ultra-low thermal conductivity,moderate thermal expansion coefficients,and high hardness among three five-component high-entropy samples.Thus,5HEC-1 with superior thermal barrier and mechanical properties can be used as promising thermal insulating materials.

The Renminbi Exchange Rate Reform and the Rebalancing of China's Growth Model

This paper posits that a proper way to estimate the Renminbi(RMB) exchange rate is to base the evaluation on the Balassa-Samuelson effect, and that the optimal way to facilitate China's growth model transformation is gradual RMB internationalization and capital account liberalization. Regression estimates show that the gross domestic product per capita growth rate, or the productivity growth rate, has strong explanatory validity when estimating the RMB exchange rate. The findings further assert that, as the growth of gross fixed capital formation slows, and the growth of household consumption speeds up, China's economic growth will be sustained. The RMB exchange rate regime is one in which gradual reforms must yield to interest rates levels and hence should only be revalued conditionally.

Can returnee managers promote CSR performance？ Evidence from China

With growing economic globalization, returnee managers who have obtained education or work experience overseas play a much more crucial role in corporations, especially in emerging economies. Using hand-collected managerial background data from a sample of firms listed on the Shanghai and Shenzhen Stock Exchanges from 2010 to 2014, this paper investigates the impact of returnee managers on corporate social responsibility （CSR） performance. We find that returnee managers can promote CSR performance. Further analyses show that the impact of returnee managers on CSR is more pronounced when managers have a foreign study background compared to managers with foreign work experience. The impact only holds when managers obtained their experience in developed economies. When enterprises face greater information asymmetry, returnee managers are more willing to use CSR as a tool to convey a positive image to stakeholders. CSR can help managers reduce information asymmetry and improve firm value. The results are robust through a series of robustness checks including a propensity score matching （PSM） procedure and a Heckman two-state sample selection model. This paper contributes to growing studies on the economic consequences of returnee managers and advances our understanding of the determinants of CSR at the individual level. The results also have implications for government and enterprises attracting talents with overseas experience.

Customer concentration and management earnings forecast

Customers are one of the key external stakeholders for a company.Using Chinese listed companies’data from 2007 to 2015,this paper examines the impact of customer concentration on information disclosure from the perspective of management earnings forecast.Empirical results show that a more concentrated customer base induces companies to disclose more positive earnings forecast.In addition,the positive association between customer concentration and management earnings forecast is more pronounced with higher economic policy uncertainty.Further analyses reveal that companies issue more positive earnings forecast to reduce the financing risk and protect their relationshipspecific investment.Also,customer concentration reduces the consistency of earnings forecast since the deviation of the forecast performance and the actual performance is greater.This paper enriches the literature on the determinants of management earnings forecast and the effects of stakeholders on corporate financial behaviour.Our findings also provide implications for investors,regulators,and various stakeholders to understand management earnings forecast decisions.

Does development of financial markets help firm innovation?Evidence from China

This paper examines the impact of financial market development on firm R&D investment.Using hand-collected R&D investment data of 221 high-tech firms listed in China’s small and mediumsized board in the period of 2009–2015,we find that equity financing,particularly internal cash flow,is the main source for R&D investment of high-tech firms.Mature firms make more use of debt financing than young ones and are faced with less severe financial constraints.The development of financial markets relieves the dependence of R&D investment on internal capital,and the effect is more recognisable in young firms than in mature ones.However,the constraint of debt financing is not alleviated as much as that of equity financing by financial deepening,which suggests that debt markets still need developing,and more favourable policies are necessary for innovative firms.

The Timing of Annual Report Disclosure:Characteristics and Economic Consequences——Evidence from Two Stock Exchanges in China

This paper analyzes the annual reports(from 1997 to 2011)of firms listed on two stock exchanges in China and reveals four significant characteristics of disclosure timing.These characteristics have significant economic implications for stock market movement,including positive contributions to stock price,trading volume and abnormal return.It thereby demonstrates that the CSRC’s"balanced disclosure"policy has not been working as expected and needs further review and improvement.

Environmental subsidies and companies’environmental investments

Environmental subsidies are important means for the government to promote companies to fulfil environmental protection responsibilities.Employing a text analysis method,this study obtains the data on government subsidies for environmental protection of Ashare listed companies in China from 2007 to 2016.Empirical estimates show that the subsidies received by companies promote their environmental inputs.Additionally,analyst tracking and internal control enhance the positive effect of subsidies on the companies’environmental investments.The above results are still valid after testing the Heckman two-stage model and the Propensity-Score-Matching and Difference-in-Difference model.This paper provides evidential support for the effectiveness of government subsidies and explores feasible ways to improve the efficiency of government subsidies based on the corporate governance channels.

Government Subsidy,Investment and Financing Constraints,and the Formation of Zombie Companies

Zombie companies have serious adverse effects on economic development.The relationship between government subsidies and zombie companies is a focus in China’s supply-side structural reform.In this paper,we classify companies into two categories:investment-constrained companies lacking investment opportunities,and fi nancing-constrained companies with limited sources of capital.Based on data of A-share listed companies from 2007 to 2016,this paper examines the relationship between government subsidies and the zombification of companies subject to different types of constraints.We find that more government subsidies have been allotted to investment-constrained companies than financing-constrained ones;government subsidy is one of the various factors that have contributed to company zombification,but the correlation is only significant for investment-constrained companies;financing subsidy dedicated to expanding corporate financing is more effective in helping investment-constrained companies than government subsidies in general,but neither government subsidies nor financing subsidies are effective in preventing investment-constrained companies from turning into zombies.In the robustness test that controls the endogeneity problem of reverse causality,replaces proxy variables,lags subsidy variables and discusses the zombification of loss-making enterprises,the results are still valid.This paper provides a heterogeneous perspective to study the connection between government subsidies and the formation of zombie companies,and in view of subsidy mismatch,puts forward recommendations regarding the use of government subsidies.

Advanced rare earth tantalate RETaO_(4)(RE=Dy,Gd and Sm) with excellent oxygen/thermal barrier performance

Thermal barrier coatings(TBCs) materials with lowered the rmal and oxygen ion conductivity can provide thermal and oxidative protection for high te mperature hot-end components in aero nautical engines and gas turbines,The rare-earth tantalate RETaO_(4)(RE=Dy,Gd and Sm) ceramics with monoclinic(m) phase were successfully synthesized via spark plasma sintering.Oxygen vacancies responsible for the thermal and oxygen ion conductivities of RETaO_(4) were demonstrated by atomic-resolution energy dispersive Xray and X-ray photoelectron spectroscopy.Among the three samples,DyTaO_(4) has excellent oxygen/thermal barrier performance.Compared to the current service thermal barrier coating material ZrO_(2)-8 wt% Y_(2)O_(3)(8 YSZ),DyTaO_(4) has an ultra-low oxygen ion conductivity benefiting from low oxygen vacancy concentration and strong stretching force constants.The intrinsic thermal conductivity of DyTaO_(4)is 68.2% less than that of 8 YSZ.Additionally,the thermal expansion rate curves indicate that the phase transformation does not happen from room te mperature to 1200℃.The above results demonstrate that high-growth rate the rmally grown oxide can be retarded by creating dense DyTaO_(4) coating with lowered thermal and oxygen ion conductivity.