Search

As a special group signature, ring signature has been widely used in anonymous voting, anonymous deposit and anonymous transaction because it can not only complete the signature without the cooperation of ring members, but also ensure the anonymity of the signer. Firstly, this paper takes time as the main line, divides the development of ring signatures into different stages, and divides ring signatures into threshold ring signatures, linkable ring signatures, ring signatures with revocable anonymity, and repudiable ring signatures according to the attributes in each stage. Through the analysis of the development process of ring signature, it can be seen that the research progress of ring signature in the field of threshold ring signature and linkable ring signature is prominent, and their application fields are also the most extensive. In the post-quantum era, cryptographic schemes based on traditional number theory problems such as large integer factorization and discrete logarithms are no longer secure, and lattice-based public key cryptography has become the best candidate for cryptographic standards in the post-quantum era because of its advantages such as quantum-immune, the reduction of the worst-case to average-case, and so on. Therefore, this paper focuses on the detailed analysis and efficiency comparison of existing lattice-based threshold ring signatures and lattice-based linkable ring signatures. The inherent anonymity of ring signatures makes them have unique advantages in the era of industrial blockchain, so this paper elaborates on several applications of ring signatures in blockchain. For example, the application of ring signature in anonymous voting, medical data sharing, and Internet of vehicles is summarized and analyzed. The application significance of ring signature in the fields of virtual currency, SIP cloud call protocol, and Ad Hoc network is briefly sorted out. Finally, the research of ring signature technology in recent years is analyzed, and the current problems are summarized.

To achieve commercial application of organic solar cells (OSCs), it is necessary to reduce material costs and improve device efficiency. This paper reports on the utilization of a multifunctional building block, namely 3‐cyanoesterthiophene, which exhibits simple structure and accessibility of synthetic for cost‐effective and high‐performance polymer donors (PDs). Meanwhile, ternary and terpolymerization strategies have been studied. Two similar PDs, PBTCl0‐TCA and PBTCl100‐TCA, are synthesized, and the devices exhibit less‐than‐satisfactory efficiency of 13.21% and 11.53% due to mismatching energy level and imperfect morphology. The two PDs with comparable structures and commendable compatibility easily form alloy‐like phase in active layer, which can effectively boost the efficiency of ternary devices to 14.17% with retained high JSC and significant improved open‐circuit voltage (VOC) and fill factor (FF). Encouraged by the ternary blending phenomenon, a polymer donor (PBTCl50‐TCA) with same ratio by random terpolymerization is designed. And over 17% efficiency binary OSCs using terpolymerization donor are demonstrated. The synergies of incorporation of the cyanoester‐group and terpolymer endow the developed PDs with deep‐lying energy levels, face‐on orientation, thermodynamic miscibility with the prevailing nonfullerene acceptor and appropriate polymer crystallinity. The findings study provide valuable insights and support for the advancement of cost‐effective and high‐performance PDs. [ABSTRACT FROM AUTHOR]

In this study, we report the fabrication, characterization, and modeling of a zigzag nanorod-structured graded-index antireflection coating fabricated by the oblique angle deposition (OAD) method. The optical properties of the reported coating were engineered by sculpting its composition and morphology using OAD, and the coating was designed to work with high-index, YAG:Ce ceramic phosphor plates. The coating enhances the normal-direction transmission of the phosphor plate over the broad visible-light spectrum. At 764 nm, the transmission is enhanced by 7.82%, compared to a potential maximum enhancement of 8.53%. For 633-nm light incident at 5°, the reported coating was measured to induce scattering loss of no greater than 1.27%. We developed a mathematical model that can use the OAD morphology information, developed from the film growth mechanism, as input parameters to simulate the optical properties of the nanostructured coatings. A finite-difference time-domain (FDTD) simulation was able to capture the polarization-dependent, antireflective performance of the coating, and the simulated transmission spectrum was in good agreement with both the measured spectrum and the spectrum calculated using the measured effective refractive indices in a transfer matrix formulation. In addition, the FDTD model was applied to predict the scattering losses. The simulation supports the experimental results and shows that the coating induces very weak scattering loss. [ABSTRACT FROM AUTHOR]

Process parameters affecting the photocatalytic performance of thin films of titanium dioxide were investigated. Nanorods of titanium dioxide were grown using the technique of oblique angle deposition to create porous films of high surface area. The surface area of the films was measured as a function of deposition angle using krypton gas adsorption and compared with the photocatalytic activity of the films. The maximum surface area achieved was 148 m2/g for films deposited at a 70° angle. A gas chamber outfitted with a volatile organic compound sensor was constructed to monitor the breakdown of isobutylene test gas. The reaction rate, normalized by the film thickness, increased with measured surface area, as expected. Annealing the deposited films was required for best performance, and annealing times of only 3 min were sufficient to maximize the reaction rate, with longer times resulting in a decrease in activity. The annealing environment was not a factor. Nitrogen worked as well as oxygen. The films were found to be oxygen rich at their immediate surface but oxygen deficient in their interior regardless of annealing environment. On a per mass basis, the nanorod film outperformed standard TiO2 nanoparticle films. [ABSTRACT FROM AUTHOR]

Aim: Cement leakage remains a significant clinical problem associated with vertebroplasty and kyphoplasty procedures, with uncontrolled cement flow in the posterior direction causing leakage into the vertebral veins or spinal canal that leads to potentially serious clinical complications. This meta-analysis compared the incidences of cement leakage between unilateral and bilateral percutaneous vertebral augmentation (PVA) in the treatment of osteoporosis vertebral compression fractures., Material and Methods: Pertinent studies were identified by a search of the PubMed, Embase, and Web of Science databases up to December 2020. The risk ratio (RR) or weighted mean difference (WMD) was applied to combine the results, and a random-effects or a fixed-effects model was used to pool the results depending on the heterogeneity among studies. Publication bias was estimated using Egger's regression asymmetry test., Results: A total of 16 trials (including 9 RCTs and 7 cohort studies) met the inclusion criteria and were included in this meta-analysis. The incidences of cement leakage were similar between the bilateral PVA and unilateral PVA groups (RR = 0.80, 95%CI: 0.57, 1.11; P = 0.182) but unilateral PVA required less cement volume (WMD = -1.34 ml, 95%CI: -1.87, -0.81; P 0.001). Subgroup analysis revealed that the incidence of cement leakage was significantly lower in the unilateral PKP group than in the bilateral PKP group (RR = 0.65, 95%CI: 0.44, 0.97; P = 0.034)., Conclusion: The incidences of cement leakage were similar between unilateral and bilateral PVA, but unilateral PVA required less cement. More large-scale studies are needed to verify our findings.

Investigating the electroencephalography (EEG) correlates of human emotional experiences has attracted increasing interest in the field of affective computing. Substantial progress has been made during the past decades, mainly by using EEG features extracted from localized brain activities. The present study explored a brain network-based feature defined by EEG microstates for a possible representation of emotional experiences. A publicly available and widely used benchmarking EEG dataset called DEAP was used, in which 32 participants watched 40 one-minute music videos with their 32channel EEG recorded. Four quasi-stable prototypical microstates were obtained, and their temporal parameters were extracted as features. In random forest regression, the microstate features showed better performances for decoding valence (model fitting mean squared error (MSE) = 3.85±0.28 and 4.07 ± 0.30, respectively, p = 0.022) and comparable performances for decoding arousal (MSE = 3.30±0.30 and 3.41 ±0.31, respectively, p = 0.169), as compared to conventional spectral power features. As microstate features describe neural activities from a global spatiotemporal dynamical perspective, our findings demonstrate a possible new mechanism for understanding human emotion and provide a promising type of EEG feature for affective computing.

2019 Novel coronavirus (2019-nCoV) infection caused a pandemic in the world. From the reported cases in the literatures, the level of D-dimer in patients with coronavirus disease 2019 (COVID-19) is positively correlated with the severity of illness, which needs the attention of clinical workers. According to Western medicine, the increase of D-dimer is related to the hyperactivity of fibrinolytic system and the shortening of prothrombin time (PT), resulting in excessive production and degradation of plasma fibrin and hypercoagulable state of blood, while traditional Chinese medicine (TCM) believes that the above syndromes belong to the pathogenesis of "blood stasis" according to TCM theories. Over the years, TCM has a significant effect on promoting blood circulation, removing blood stasis and improving microcirculation. This article reviews the mechanism, clinical significance, understanding of TCM and common methods of promoting blood circulation and removing blood stasis caused by 2019-nCoV, in order to provide ideas for the prevention and treatment of impaired blood coagulation in patients with COVID-19.

A composite film made of a stable gold nanoparticle (NP) array with well-controlled separation and size atop a TiO 2 nanorod film was fabricated via the oblique angle deposition (OAD) technique. The fabrication of the NP array is based on controlled, Rayleigh-instability-induced, solid-state dewetting of as-deposited gold aggregates on the TiO 2 nanorods. It was found that the initial spacing between as-deposited gold aggregates along the vapor flux direction should be greater than the TiO 2 interrod spacing created by 80° OAD to control dewetting and produce NP arrays. A numerical investigation of the process was conducted using a phase-field modeling approach. Simulation results showed that coalescence between neighboring gold aggregates is likely to have caused the uncontrolled dewetting in the 80° deposition, and this could be circumvented if the initial spacing between gold aggregates is larger than a critical value s min . We also found that TiO 2 nanorod tips affect dewetting dynamics differently than planar TiO 2 . The topology of the tips can induce contact line pinning and an increase in the contact angle along the vapor flux direction to the supported gold aggregates. These two effects are beneficial for the fabrication of monodisperse NPs based on Rayleigh-instability-governed self-assembly of materials, as they help to circumvent the undesired coalescence and facilitate the instability growth on the supported material. The findings uncover the application potential of OAD as a new method to fabricate structured films as template substrates to mediate dewetting. The reported composite films would have uses in optical coatings and photocatalytic systems, taking advantage of their ability to combine plasmonic nanostructures within a nanostructured dielectric film.