The growing characteristics of splicing misoriented KDP seeds of both bulk and thin pieces were investigated. The chemical etching method was used to determine the prismatic and Z-plate surfaces of the crystals grown by splicing bulk KDP seeds. The X-ray Lang topography method was employed to measure original thin platy crystals grown by splicing thin pieces of KDP seeds. From the results it can be concluded that when the misorientation of two seeds on the Z-axis direction was about 1.5°, the crystal was grown successfully if the secondary capping was controlled properly. In comparison with the growth of splicing “parallel” seeds, the misorientation of both seeds increases such that the secondary capping becomes difficult, the sub-grain boundary stretches longer, the stress field around the secondary cap enlarges and the crystals grown crack easily. 相似文献
Catalysts involving post-transition metals have shown almost invincible performance on generating formate in electrochemical CO2 reduction reaction (CO2RR). Conversely, Cu without post-transition metals has struggled to achieve comparable activity. In this study, a sulfur (S)-doped-copper (Cu)-based catalyst is developed, exhibiting excellent performance in formate generation with a maximum Faradaic efficiency of 92 % and a partial current density of 321 mA cm−2. Ex situ structural elucidations reveal the presence of abundant grain boundaries and high retention of S−S bonds from the covellite phase during CO2RR. Furthermore, thermodynamic calculations demonstrate that S−S bonds can moderate the binding energies with various intermediates, further improving the activity of the formate pathway. This work is significant in modifying a low-cost catalyst (Cu) with a non-metallic element (S) to achieve comparable performance to mainstream catalysts for formate generation in industrial grade. 相似文献
Based on the asymmetric quantum cryptosystem, a new public-key quantum signature scheme is proposed. In our scheme, the signer’s public key is derived from her public identity information, and the corresponding private key is generated by the trusted private key generator (PKG). Both of the public key and the private key are classical bit strings, so they are easily kept. It is very convenient for the key management of the quantum signature system. The signer signs a message with her private key, and the quantum signature can be publicly verified with the signer’s public key and the quantum one-way function. Both of the private key and public key can be reused. On the other hand, in the signing phase, the signer sends the message to PKG via a classical unencrypted channel, which can be used to authenticate the identity of the signer. The proposed scheme has the properties of completeness, information-theoretic security, non-repudiation and unforgeability. Its information-theoretic security is ensured by quantum indistinguishability mechanics. On the other hand, our scheme is more efficient than the similar schemes.
