The impact-resistance analysis of a fastening belt of an underwater vehicle life raft

In this paper, the impact resistance of a fastening belt of the underwater vehicle life raft is studied, which is based on Germany BV043/85 standard. Performing finite element simulation for the fastening belt with ANSYS Workbench software. Calculating the deformation and stress distribution of the fastening belt under impact loading. This method can accurately reflect the impact resistance of the fastening belt. Comparing with the design requirements can verify the reliability of the fastening belt

A Novel Role for microRNA-214 in Inflammatory Smooth Muscle Cell Differentiation from Adventitia Stem/progenitor Cells and Arterial Remodelling

PhD ThesisBackground: Cardiovascular disease (CVD) is still the leading cause of death in the developed as well as developing country. Atherosclerosis and neointima formation considered as chronic inflammatory diseases, in which many cells including inflammatory smooth muscle cell (iSMC) were involved. ISMC differentiation from vascular adventitia stem/progenitor cells (AdSPCs) has been recently recognised as a critical determinant in cardiovascular diseases. One study have recently reported an important role for microRNA-214 (miR-214) in mature vascular SMC functions and injury-induced neointima formation. However, little is known about the functional involvements of miR-214 in iSMC differentiation from AdSPCs and its contribution to adverse arterial remodelling. Purpose: In this PhD study, I aimed to study the functional importance of miR-214 and its target gene in iSMC differentiation from AdSPCs and neointima SMC hyperplasia. Results: miR-214 expression was significantly increased during SMC differentiation from AdSPCs in response to TGFβ1. miR-214 gain/loss-offunction assays showed that miR-214 plays an important role in SMC differentiation from AdSPCs. By co-incubating AdSPCs with TGFβ1 and TNFα, AdSPCs were induced to differentiate toward iSMCs as evident by a decreased expression level of SMC-specific genes, but an increased level of inflammatory genes in iSMCs. Importantly, such phenotype could be reverted by miR-214 over-expression. I observed that sonic hedgehogglioma- associated oncogene 1 (Shh-GLI1) signal was closely modulated during iSMC differentiation, and demonstrated that Suppressor of Fused (SuFu) is the functional target of miR-214 controlling iSMC generation from AdSPCs. Further mechanistic studies revealed that increased amount of the GLI1 protein was translocalized into nuclei in miR-214 over-expressing or 6 SuFu knockdown cells, and the consensus sequence (GACCACCCA) of GLI1 within gene promoters of smooth muscle alpha-actin (SMαA) and serum response factor (SRF) was required for their regulation by miR-214 and SuFu. Additionally, Sufu also functions as a positive regulator for inflammatory gene regulations in iSMCs. In vivo, I demonstrated that locally enforced expression of miR-214 in the injured vessels significantly reduced SuFu expression level, iSMC generation, and inhibited neointima SMC hyperplasia after injury. Importantly, I observed that perivascularly transplanted AdSPCs significant contribute to neointima SMC hyperplasia by differentiating to iSMCs, and miR-214 over-expression could reverse such an effect. Finally, a decreased expression level of miR-214, but increased expression level of Sufu was observed in diseased human arteries. Conclusions/Implications: This thesis reports an unexplored role for miR- 214 in iSMC differentiation from AdSPCs and controlling neointima iSMC hyperplasia. These findings provide new insights into the therapeutic effect of miR-214 in vascular diseases

Screening Retinopathy of Prematurity in Extremely Low Birth Weight Infants in China and the Need for Earlier Screening Times

Purpose. To convey the need for a revised screening strategy for retinopathy of prematurity (ROP) for extremely low birth weight (ELBW) infants in China. Design. A retrospective longitudinal study. Methods. The medical charts of infants with a birth weight (BW) of less than 1 kg were reviewed. The infants were divided into three groups: group A, without ROP; group B, with ROP but not up to type 1 prethreshold or threshold ROP; group C, with type 1 prethreshold or threshold ROP. Data collected included gender, gestational age (GA), BW, postmenstrual age (PMA), age of onset of ROP, and age at which treatment was carried out, if required. Results. A total of 77 infants were involved. Fifty-six infants developed ROP at any stage and 38 infants developed type 1 prethreshold or threshold ROP. The mean BW and GA of infants in group A were significantly different compared with groups B and C. The mean PMA of onset of ROP in infants who developed mild ROP was 37 weeks compared with 34 weeks for infants who developed severe ROP. Conclusion. ELBW infants have a higher incidence of ROP in China which highlights the need for optimizing neonatal care for these infants. In ELBW infants, ROP tends to develop more severely when it occurs earlier. It is necessary for ELBW infants, especially for those with a BW less than 800 g or a GA less than 25 weeks, to be initially screened at an earlier time

Convergence of energy-dependent incommensurate antiferromagnetic neutron scattering peaks to commensurate resonance in underdoped bilayer cuprates

The recently discovered coexistence of incommensurate antiferromagnetic neutron scattering peaks and commensurate resonance in underdoped YBa$_2$Cu$_3$O$_{6+x}$ is calling for an explanation. Within the t-J model, the doping and energy dependence of the spin dynamics of the underdoped bilayer cuprates in the normal state is studied based on the fermion-spin theory by considering the bilayer interactions. Incommensurate peaks are found at $[(1\pm\delta)\pi,\pi]$ and $[\pi,(1\pm\delta)\pi]$ at low energies with $\delta$ initially increasing with doping at low dopings and then saturating at higher dopings. These incommensurate peaks are suppressed, and the parameter $\delta$ is reduced with increasing energy. Eventually it converges to the $[\pi,\pi]$ resonance peak. Thus the recently observed coexistence is interpreted in terms of bilayer interactions.Comment: 15 pages, Revtex, five figures are included, accepted for publication in Phys. Rev.

Wind Power, Hydropower and Thermal Power Combined Low-Carbon Maintenance Optimization Based on Continuous Hidden Markov Model

[Introduction] In the context of the new power system, low-carbon maintenance of wind turbines and coordinated maintenance with conventional wind turbine generator systems (WTGS) need to be solved urgently. In this paper, taking into account the impact of multi-attribute meteorological factors and low carbon and economic needs, an optimization model for wind power, hydropower and thermal power combined low-carbon maintenance based on continuous hidden Markov model is established. [Method] Firstly, dynamic tracking of wind farm maintenance capacity was realized by taking rainfall, wind speed and lightning hazard degree as the observation sequence, taking maintenance capacity as hidden state sequence, and using continuous hidden Markov model (CHMM) process. Then, an optimization model for wind power, hydropower and thermal power combined low-carbon maintenance was constructed by taking the optimal maintenance capacity as the decision-making basis, taking the minimum total cost as the optimization objective, and taking the maintenance constraints and system control constraints into consideration. Finally, took the IEEE30-node system as an example. [Result] The results show that the proposed model has more significant economic benefits and low carbon characteristics. [Conclusion] The research in this paper has high theoretical value for the operation and maintenance of WTGS, and has strong engineering applicability

The effects of disorder and interactions on the Anderson transition in doped Graphene

We undertake an exact numerical study of the effects of disorder on the Anderson localization of electronic states in graphene. Analyzing the scaling behaviors of inverse participation ratio and geometrically averaged density of states, we find that Anderson metal-insulator transition can be introduced by the presence of quenched random disorder. In contrast with the conventional picture of localization, four mobility edges can be observed for the honeycomb lattice with specific disorder strength and impurity concentration. Considering the screening effects of interactions on disorder potentials, the experimental findings of the scale enlarges of puddles can be explained by reviewing the effects of both interactions and disorder.Comment: 7 pages, 7 figure

Energy dependence of commensurate neutron scattering peak in doped two-leg ladder antiferromagnet Sr_{14-x}Ca_{x}Cu_{24}O_{41}

The dynamical spin response of doped two-leg ladder antiferromagnets is investigated based on the fermion-spin approach. Our calculations clearly demonstrate a crossover from the incommensurate antiferromagnetism in the weak interchain coupling regime to commensurate spin fluctuation in the strong interchain coupling regime. In particular, the nuclear spin-lattice relaxation rate extracted from the commensurate spin fluctuation decreases exponentially with decreasing temperatures. The behaviors of the spin dynamics in the strong coupling regime are quantitatively close to the experimental results of Sr_{14-x}Ca_{x}Cu_{24}O_{41}.Comment: 13 pages, Revtex, four figures are include

Pseudogap and its connection to particle-hole asymmetry electronic state and Fermi arcs in cuprate superconductors

The particle-hole asymmetry electronic state of cuprate superconductors and the related doping and temperature dependence of the Fermi arc length are studied based on the kinetic energy driven superconducting mechanism. By taking into account the interplay between the SC gap and normal-state pseudogap, the essential feature of the evolution of the Fermi arc length with doping and temperature is qualitatively reproduced. It is shown that the particle-hole asymmetry electronic state is a natural consequence due to the presence the normal-state pseudogap in the particle-hole channel. The Fermi arc length increases with increasing temperatures below the normal-state pseudogap crossover temperature $T^{*}$, and it covers the full length of the Fermi surface for $T>T^{*}$. In particular, in analogy to the temperature dependence of the Fermi arc length, the low-temperature Fermi arc length in the underdoped regime increases with increasing doping, and then it evolves into a continuous contour in momentum space near the end of the superconducting dome. The theory also predicts an almost linear doping dependence of the Fermi arc length.Comment: 9 pages, 8 figure