Direct growth of graphene films without catalyst on flexible glass substrates by PECVD

A hydrogen-plasma-etching-based plasma-enhanced chemical vapor deposition(PECVD)synthesis route without metal catalyst for preparing the graphene films on flexible glass is developed.The quality of the prepared graphene films is evaluated by scanning electron microscopy,x-ray photoelectron spectroscopy,high-resolution transmission electron microscopy,ultraviolet-visible spectroscopy,and electrochemical measurements.In a radio frequency(RF)power range of 50 W-300 W,the graphene growth rate increases with RF power increasing,while the intensity ratio of D-to G-Raman peak(I_(D)/I_(G))decreases.When the RF power is higher than 300 W,the I_(D)/I_(G)rises again.By optimizing experimental parameters of hydrogen plasma etching and RF power,the properties of as-prepared flexible graphene on glass are modulated to be able to achieve the graphene's transparency,good electrical conductivity,and better macroscopic uniformity.Direct growth of graphene film without any metal catalyst on flexible glass can be a promising candidate for applications in flexible transparent optoelectronics.

Possibility to break through limitation of measurement range in dual-wavelength digital holography

By using the beat frequency technique,the dual-wavelength digital holography(DWDH)can greatly increase the measurement range of the system.However,the beat frequency technique has a limitation in measurement range.The measurement range is not larger than a synthetic wavelength.Here,to break through this limitation,we propose a novel DWDH method based on the constrained underdetermined equations,which consists of three parts:(i)prove that the constrained underdetermined equation has a unique integer solution,(ii)design an algorithm to search for the unique integer solution,(iii)introduce a third wavelength into the DWDH system,and design a corresponding algorithm to enhance the anti-noise performance of DWDH.As far as we know,it is the first time that we have discovered that the problem of DWDH can belong in a problem of contained underdetermined equations,and it is also the first time that we have given the mathematical proof for breaking through the limitation of the measurement range.A series of results is shown to test the theory and the corresponding algorithms.More importantly,since the principle of proposed DWDH is based on basic mathematical principles,it can be further extended to various fields,such as dual-wavelength microwave imaging and dual-wavelength coherent diffraction imaging.

Transition parameters of Li-like ions(Z=7-11)in dense plasmas

The energy levels,transition energies,transition probabilities,weighted oscillator strengths,and line strengths of Li-like ions(Z=7-11)in dense plasmas are investigated in this work.The relativistic effects and electron correlation effects are described by the MCDHF method.The ion sphere model is applied to include the dense plasma screening effect.The ground configuration 1s^(2)2s and the excited 1s^(2)2p,1s^(2)3l(l=0-2)are considered.The configuration sets are enlarged until n=7 where the calculated energy levels have converged.The critical free electron densities of 1s^(2)3d states are estimated.Except for 1s^(2)3s-1s^(2)3p transitions,the transition energies for△n=0 increase,and for△n≠0 decrease with increasing free electron densities.For 1s^(2)3s-1s^(2)3p transitions,the spectra show blue-shift at lower free electron densities and red-shift at higher free electron densities,and the energy level crossing phenomens are observed at higher free electron densities.

Study on the Realization Process of the Updating of Marxism

The updating of Marxism is to combine Marxism with the present characteristics of the times to touch the pulse of the times,reflect the spirit of the times and address the subject of the times,enabling it to adapt to the requirements of the times and lead the trend of the times.It is a historical process of constantly promoting Marxism to move with the times,a development process of mutual unification of theoretical innovation and practice innovation and a historical process of periodical development and constant advancement.The updating of Marxism is a process that is continuously pushed ahead in the two-way interactions of Marxist theory and conditions of the times.Further researches on the main sections contained in this process have a great significance in the process,in which we profoundly master the laws of the updating of Marxism and constantly advance the updating of Marxism.

Efficient self-testing system for quantum computations based on permutations

Verification in quantum computations is crucial since quantum systems are extremely vulnerable to the environment.However,verifying directly the output of a quantum computation is difficult since we know that efficiently simulating a large-scale quantum computation on a classical computer is usually thought to be impossible.To overcome this difficulty,we propose a self-testing system for quantum computations,which can be used to verify if a quantum computation is performed correctly by itself.Our basic idea is using some extra ancilla qubits to test the output of the computation.We design two kinds of permutation circuits into the original quantum circuit:one is applied on the ancilla qubits whose output indicates the testing information,the other is applied on all qubits(including ancilla qubits) which is aiming to uniformly permute the positions of all qubits.We show that both permutation circuits are easy to achieve.By this way,we prove that any quantum computation has an efficient self-testing system.In the end,we also discuss the relation between our self-testing system and interactive proof systems,and show that the two systems are equivalent if the verifier is allowed to have some quantum capacity.

Identity-based searchable attribute signcryption in lattice for a blockchain-based medical system

Electronic healthcare systems can offer convenience but face the risk of data forgery and information leakage.To solve these issues,we propose an identity-based searchable attribute signcryption in lattice for a blockchain-based medical system(BCMS-LIDSASC).BCMS-LIDSASC achieves decentralization and anti-quantum security in the blockchain environment,and provides fine-grained access control and searchability.Furthermore,smart contracts are used to replace traditional trusted third parties,and the interplanetary file system(IPFS)is used for ciphertext storage to alleviate storage pressure on the blockchain.Compared to other schemes,BCMS-LIDSASC requires smaller key size and less storage,and has lower computation cost.It contributes to secure and efficient management of medical data and can protect patient privacy and ensure the integrity of electronic healthcare systems.

Enhancement of red upconversion emission intensity of Ho^(3+) ions in NaLuF4:Yb^(3+)/Ho^(3+)/Ce^(3+)@NaLuF_(4) core-shell nanoparticles

The red upconversion emission of Ho^(3+)ions,in the optical window of biological tissue,exhibits excellent prospects in biological applications.This study aims to enhance the red upconversion emission intensity of Ho^(3+)ions in NaLuF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+) nanoparticles through building different core–shell structures with different excitation wavelengths.A significantly enhanced red upconversion emission with a higher red-to-green ratio was successfully obtained in NaLuF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaLuF_(4) core–shell nanoparticles by introducing the Yb^(3+)and Yb^(3+)/Nd^(3+)ions into the NaLuF_(4) shell,with enhancement of the red emission occurring when Yb^(3+)and Nd^(3+)ions in the shell transfer more excitation energy to the Ho^(3+)ions.Investigation of the red emission enhancement mechanism is based on spectral characteristics and lifetimes.We examined the synergistic effect of dual-wavelength co-excitation NaLuF_(4):20%Yb^(3+)/2%Ho^(3+)/12%Ce^(3+)@NaLuF_(4):10%Yb^(3+)/15%Nd^(3+)core–shell nanoparticles to establish optimal excitation conditions.It is hoped that this method,using red upconversion emission core–shell nanoparticles with multi-mode excitation,can provide new ways to expand the applications of rare-earth luminescent materials in biomedicine and anti-counterfeiting.

An offset cancellation technique in a switched-capacitor comparator for SAR ADCs

An offset cancellation technique for a SAR （successive approximation register） ADC switched-capacitor comparator is described. The comparator is designed with a pre-amplifying and regenerative latching structure and realized in 0.18μm CMOS. With the first stage preamplifier offset cancellation and low offset regenerative latching approach, the equivalent offset of the comparator is reduced to 〈 0.55 mV. By using the pre-amplifying and regenerative latching comparison mode the comparator exhibits low power dissipation. Under a 1.8 V power supply, with a 200 kS/s ADC sampling rate and 3 MHz clock frequency, a 13-bit comparison resolution is reached and less than 0.09 mW power dissipation is consumed. The superiority of this comparator is discussed and proved by the post-simulation and application to a 10 bit 200 kS/s touch screen SAR A/D converter.

Novel efficient identity-based signature on lattices

With the rapid development of electronic information technology,digital signature has become an indispensable part of our lives.Traditional public key certificate cryptosystems cannot overcome the limitations of certificate management.Identity-based cryptosystems can avoid the certificate management issues.The development of quantum computers has brought serious challenges to traditional cryptography.Post-quantum cryptography research is imperative.At present,almost all post-quantum identity-based signature(IBS)schemes are constructed using Gaussian sampling or trapdoor technologies.However,these two technologies have a great impact on computational efficiency.To overcome this problem,we construct an IBS scheme on lattices by employing Lyubashevsky’s signature scheme.Based on the shortest vector problem on lattices,our scheme does not use Gaussian sampling or trapdoor technologies.In the random oracle model,it is proved that our scheme is strongly unforgeable against adaptive chosen messages and identity attacks.The security level of our scheme is strongly unforgeable,which is a higher level than the existential unforgeability of other schemes.Compared with other efficient schemes,our scheme has advantages in computation complexity and security.