A method for the resonant response evaluation of blades system with underplatform dampers

The friction damper has been widely used to reduce the resonant vibration of blades. The harmonic balance method is a well-known method for the linearization of the nonlinear friction force. Meanwhile Mindlin gives analytical expression to describe the nonlinear friction force during stick contact condition, therefore the nonlinear force is represented by two linear coefficients, i.e., equivalent stiffness and equivalent damping. In this work, the stiffness matrix and mass matrix are normalized to a lumped mass and corresponding stiffness according to the definition of stiffness and modal mode. For blades system with underplatform dampers, the dynamic equation for multi lumped mass system is derived and also the iteration method is listed. At last, the experiment verification is conducted using 2 plate blades with underplatform damper. The comparison shows a good agreement in both resonant response and resonant frequency for low normal load cases, and still capture the tendency for high normal load cases

Research on Situation of Chinese Excellent Athletes Disability Mutual Insurance

Athlete as a career has the characteristics of high risk. There are about 70% Chinese athletes who are in different degree of disability. As a consequence, the issue of disability security for athletes has always been taken seriously. Through researching on the development of Chinese excellent athletes disability mutual insurance, collecting and analysing the data of disability mutual insurance from 2007 to 2012 which was published by China Sports Foundation, it is obvious that relatively small number of athletes participate in Chinese excellent athletes disability mutual Insurance, and the premium is quite low. Research also shows that the degree of athletic disability is concentrated in lower rating, disability parts of different sports item have differences, and the insurance payments amount remains stable with a fact that male athletes are more than female ones

Difference and Enlightenment of Livelihood Policies Between China and the United Sates

This paper analyzes and summarizes the American livelihood policy on the basis of educational public policy, medicine and health public policy, employment and entrepreneurship public policy and compulsory education public policy four policies; learns some experiences and shortages of American livelihood policy. Based on above analyses, putting forward some enlightenments and experiences of China livelihood policy

Self-Adaptive and Relaxed Self-Adaptive Projection Methods for Solving the Multiple-Set Split Feasibility Problem

Given nonempty closed convex subsets , and nonempty closed convex subsets , , in the - and -dimensional Euclidean spaces, respectively. The multiple-set split feasibility problem (MSSFP) proposed by Censor is to find a vector such that , where is a given real matrix. It serves as a model for many inverse problems where constraints are imposed on the solutions in the domain of a linear operator as well as in the operator’s range. MSSFP has a variety of specific applications in real world, such as medical care, image reconstruction, and signal processing. In this paper, for the MSSFP, we first propose a new self-adaptive projection method by adopting Armijo-like searches, which dose not require estimating the Lipschitz constant and calculating the largest eigenvalue of the matrix ; besides, it makes a sufficient decrease of the objective function at each iteration. Then we introduce a relaxed self-adaptive projection method by using projections onto half-spaces instead of those onto convex sets. Obviously, the latter are easy to implement. Global convergence for both methods is proved under a suitable condition

State Consensus Analysis and Design for High-Order Discrete-Time Linear Multiagent Systems

The paper deals with the state consensus problem of high-order discrete-time linear multiagent systems (DLMASs) with fixed information topologies. We consider three aspects of the consensus analysis and design problem: (1) the convergence criteria of global state consensus, (2) the calculation of the state consensus function, and (3) the determination of the weighted matrix and the feedback gain matrix in the consensus protocol. We solve the consensus problem by proposing a linear transformation to translate it into a partial stability problem. Based on the approach, we obtain necessary and sufficient criteria in terms of Schur stability of matrices and present an analytical expression of the state consensus function. We also propose a design process to determine the feedback gain matrix in the consensus protocol. Finally, we extend the state consensus to the formation control. The results are explained by several numerical examples

Protein-Protein Affinity Determination by Quantitative FRET Quenching.

The molecular dissociation constant, Kd, is a well-established parameter to quantitate the affinity of protein-protein or other molecular interactions. Recently, we reported the theoretical basis and experimental procedure for Kd determination using a quantitative FRET method. Here we report a new development of Kd determination by measuring the reduction in donor fluorescence due to acceptor quenching in FRET. A new method of Kd determination was developed from the quantitative measurement of donor fluorescence quenching. The estimated Kd values of SUMO1-Ubc9 interaction based on this method are in good agreement with those determined by other technologies, including FRET acceptor emission. Thus, the acceptor-quenched approach can be used as a complement to the previously developed acceptor excitation method. The new methodology has more general applications regardless whether the acceptor is an excitable fluorophore or a quencher. Thus, these developments provide a complete methodology for protein or other molecule interaction affinity determinations in solution

Tea intake and total body bone mineral density of all ages: a Mendelian randomization analysis

BackgroundThere is increasing evidence indicating that tea intake affects bone mineral density levels; however, the causality between tea intake and bone mineral density is inconclusive. This study aimed to assess the causal relationship between tea intake and total body bone mineral density (TB-BMD) through two-sample Mendelian randomization (MR) analysis.MethodsWe conducted a two-sample MR approach to estimate the potential causal effects of tea intake on TB-BMD at all ages in a European population. The analyses were performed using summary statistics obtained for single-nucleotide polymorphisms (SNPs), identified from a genome-wide association meta-analysis of tea intake (N = up to 447,485 individuals) and from the GEnetic Factors for OSteoporosis (GEFOS) Consortium’s genome-wide association meta-analysis (N = up to 56,284 individuals), with baseline data collected in 2018 and populations derived from the European ancestry. The association between each SNP and TB-BMD was weighted by its association with tea intake, and estimates were combined mainly using an inverse-variance weighted meta-analysis. In addition, we explored the potential causal effects between green tea intake, herbal tea intake, and TB-BMD.ResultsThe MR analysis revealed that genetically determined tea intake exerts a causal impact on TB-BMD, with an odds ratio (OR) of 1.204 (95% CI: 1.062–1.366, p = 0.004), especially in the age group of 45–60 years (OR = 1.360, 95% CI: 1.088–1.700, p = 0.007). No horizontal pleiotropy and heterogeneity were observed. However, there was no causal effect of tea intake on TB-BMD in the age groups of 0–15, 15–30, 30–45, and over 60 years. In the subgroup analysis, when green tea intake was regarded as the exposure factor, no salient associations were found between green tea consumption and TB-BMD (IVW p = 0.368). Similarly, there was also no causal association between herbal tea intake and TB-BMD (IVW p = 0.264).ConclusionThe findings of this study support the evidence that tea consumption increases bone density and reduces the risk of osteoporosis in the age group of 45–60 years within the European population

Route of administration of exogenous progesterone for luteal support does not significantly affect the serum concentration in assisted reproductive technology

The objective of this research is to study the guiding role of serum progesterone level on exogenous luteal support protocols. In the retrospective study, a total of 537 infertile women undergoing IVF/ICSI were recruited. Serum samples were obtained for serum progesterone measurements. The results demonstrated that the progesterone levels of all women gradually decreased over the course of 7 days after ET. The progesterone level of the pregnant women reached a nadir on day 7 after ET and subsequently began to rise, while the progesterone level of the non-pregnant women continued to decrease. Even with different routes of administration of exogenous progesterone, the progesterone levels followed the same patterns. The serum progesterone level does not represent the adequacy of exogenous progesterone supplementation. Therefore, there is no need to measure serum progesterone levels frequently after embryo transfer or adjust the dose according to serum progesterone levels. (Afr J Reprod Health 2021; 25[6]: 134-142)