Angular velocity and contact force simulation of the spiral bevel gear meshing based on the hertz contact theory

To obtain the change tendency of the wheel’s angular velocity and tangential component of contact force with time of the pinion under the step input during spiral bevel gear meshing, the tooth flank equation of spiral bevel gear was constructed based on the Non-Uniform Rational B-splines curve. The three-dimensional model of the pinion and the wheel were built based on the tooth flank equation. The calculation equation and relative parameters set for the contact force of spiral bevel gear meshing were done based on the Hertz contact theory. A mating of spiral bevel gears was taken as an example for dynamics simulation and the simulation results show that the relative error rate of the angular velocity between simulation and theoretical calculation is 0.054%, and that the relative error rate of tangential component of the contact force between simulation and theoretical calculation is 4.82%. These findings provide the theoretical basis for dynamic characteristics optimization of the spiral bevel gears

Experimental cyclic inter-conversion between Coherence and Quantum Correlations

Quantum resource theories seek to quantify sources of non-classicality that bestow quantum technologies their operational advantage. Chief among these are studies of quantum correlations and quantum coherence. The former to isolate non-classicality in the correlations between systems, the latter to capture non-classicality of quantum superpositions within a single physical system. Here we present a scheme that cyclically inter-converts between these resources without loss. The first stage converts coherence present in an input system into correlations with an ancilla. The second stage harnesses these correlations to restore coherence on the input system by measurement of the ancilla. We experimentally demonstrate this inter-conversion process using linear optics. Our experiment highlights the connection between non-classicality of correlations and non-classicality within local quantum systems, and provides potential flexibilities in exploiting one resource to perform tasks normally associated with the other.Comment: 8 pages, 4 figures, comments welcom

Inhibitive effect of triptolide on invasiveness of human fibrosarcoma cells by downregulating matrix metalloproteinase—9 expression

AbstractObjectiveTo explore the molecular mechanisms of antitumor properties of triptolide, a bioactive component isolated from the Chinese herb Tripterygium wolfordii Hook F.MethodsHuman fibrosarcoma HT-1080 cells were treated with different doses of triptolide for 72 h. Then the expression and activity of matrix metalloproteinase (MMP)-2 and -9 were measured and the invasiveness of triptolide-treated HT-1080 cells was compared with that of anti-MMP-9-treated HT-1080 cells.Results18 nmol/L triptolide inhibited the gene expression and activity of MMP-9, but not those of MMP-2, in HT-1080 cells. In addition, both 18 nmol/L triptolide and 3 μg/mL anti-MMP-9 significantly reduced the invasive potential of HT-1080 cells, by about 50% and 35%, respectively, compared with the control. Whereas there was no significant difference between the effect of 18 nmol/L triptolide and that of anti-MMP-9 on invasive potential of HT-1080 cells.ConclusionsThese data suggest that triptolide inhibits tumor cell invasion partly by reducing MMP-9 gene expression and activity

Quantum-information transfer in a coupled resonator waveguide

We propose an efficient scheme for the implementation of quantum information transfer in a onedimensional coupled resonator waveguide. We show that, based on the effective long-range dipole-dipole interactions between the atoms mediated by the cavity modes, Raman transitions between the atoms trapped in different nodes can take place. Quantum information could be transferred directly between the opposite ends of the coupled waveguide without involving the intermediate nodes via either Raman transitions or the stimulated Raman adiabatic passages. Since this scheme, in principle, is a one-step protocol, it may provide useful applications in quantum communications.Comment: 4 pages, 4 figure

Flameless combustion with liquid fuel: A review focusing on fundamentals and gas turbine application

Flameless combustion has been developed to reduce emissions whilst retaining thermal efficiencies in combustion systems. It is characterized with its distinguished features, such as suppressed pollutant emission, homogeneous temperature distribution, reduced noise and thermal stress for burners and less restriction on fuels (since no flame stability is required). Recent research has shown the potential of flameless combustion in the power generation industry such as gas turbines. In spite of its potential, this technology needs further research and development to improve its versatility in using liquid fuels as a source of energy. In this review, progress toward application of the flameless technique is presented with emphasis on gas turbines. A systematic analysis of the state-of-the-art and the major technical and physical challenges in operating gas turbines with liquid fuels in a flameless combustion mode is presented. Combustion characteristics of flameless combustion are explained along with a thorough review of modelling and simulation of the liquid fuel fed flameless combustion. A special focus is given to the relevant research on applications to the inner turbine burners. The paper is concluded by highlighting recent findings and pointing out several further research directions to improve the flameless combustion application in gas turbines, including in-depth flow and combustion mechanisms, advanced modelling, developed experimental technology and comprehensive design methods aiming at gas turbine flameless combustors

Efficacy of a smartphone-based care support programme in improving post-traumatic stress in families with childhood cancer: Protocol of a randomised controlled trial

INTRODUCTION: Diagnosis and treatment represent distressing experiences for the families of children with cancer. Psychosocial challenges are faced by these families in China because of limited health services and resources for psychosocial oncology care. Effective interventions tailored to the knowledge level and cultural values of this population are needed. The goal of this study is to evaluate a smartphone-based care support (SBCS) programme for the families of children with cancer in China. METHODS AND ANALYSIS: A parallel randomised controlled trial will be conducted to examine the efficacy of an evidence-based and culturally tailored SBCS programme for the families of children with cancer in China. A total of 180 families will be recruited. The intervention will consist of an introduction session and four main sessions and will be conducted sequentially on a single weekend day. Participating families will be included in the intervention group. The post-traumatic stress and quality of life of families will be evaluated at baseline, during the intervention, immediately after the intervention, and 2 and 6 months after the intervention. ETHICS AND DISSEMINATION: Ethical approval for this protocol has been obtained from the Nursing and Behavioural Medicine Research Ethics Review Committee, Xiangya School of Nursing, Central South University (Protocol #: E2020125). The findings of the trial will be disseminated through conference presentations and publications in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ChiCTR2000040510

Strong Majorana evidence of a vortex from scanning tunneling microscopy with a dissipative environment

It is predicted that a vortex in a topological superconductor contains a Majorana zero mode (MZM). The confirmative Majorana signature, i.e., the $2e^2/h$ quantized conductance, however is easily sabotaged by unavoidable interruptions, e.g. instrument broadening, non-Majorana signal, and extra particle channels. We propose to avoid the signal interruption by introducing disorder-induced dissipation that couples to the tip-sample tunneling. With dissipation involved, we highlight three features, each of which alone can provide a strong evidence to identify MZM. Firstly, dissipation suppresses a finite-energy Caroli-de Gennes-Matricon (CdGM) conductance peak into a valley, while it does not split MZM zero-bias conductance peak. Secondly, we predict a dissipation-dependent scaling feature of the zero-bias conductance peak. Thirdly, the introduced dissipation manifests the MZM signal by suppressing non-topological CdGM modes. Importantly, the observation of these features does not require a quantized conductance value $2e^2/h$.Comment: 13 pages, 5 figures with reference list update