A SIMPLIFIED CALCULATING METHOD OF NONLINEAR FREQUENCY OF CABLE NET UNDER MEAN WIND LOAD

The cable net supported glass curtain wallas the most advanced technique in dot point supported glass curtain wall, is widely used in China. Because of its large deflection and high nonlinearity under wind load, the dynamic performance of the cable net is greatly different from that of the conventional linear structures. The continuous membrane theory is used to construct the nonlinear vibration differential equation of the cable net, and the harmonic balance method is used to solve the analytic formula of the nonlinear frequency. In order to verify the accuracy of the above analytic formula, the results of the formula and the nonlinear FEM time-history method are compared and found to be in good agreement. Furthermore, the nonlinear vibration differential equation and the nonlinear frequency obtained in this paper are the basis for the wind-induced response analysis of a cable net under fluctuating wind load.     

Competition between fingers in Hele-Shaw flows

In experiments on the displacement of viscous fluids in a Hele-Shaw cell of channel type the catastrophic development of competition between fingers is sometimes observed: for a long time two fingers propagate almost side by side and then one of them suddenly suppresses the other. It is believed that this is a manifestation of the capillary forces on the phase interface [1]. Using the solution found in [2] for the problem in an idealized formulation, it is shown that this scenario is perfectly feasible without having to take capillary forces into account.     

水泥聚苯模壳格构式混凝土墙体的抗侧性能试验及分析

论文介绍6片不同高宽比的水泥聚苯模壳格构式混凝土墙体在轴压力和水平往复侧推力作用下的试验,分析这种墙体的抗侧强度、刚度和延性等力学性能.试验表明,高宽比大于1的墙体破坏时表现为墙体跟部的单一水平裂缝,其他部位完好;高宽比3∶4的墙体破坏时存在多条通过格构梁柱的斜向裂缝,墙体裂缝分布密集,变形能力好.     

厚壁管道周向导波检测技术实验研究

厚壁管道是火电机组四大管道系统的核心部件,将超声导波技术应用于厚壁管道的无损检测显得十分重要.首先确定厚壁管道检测的激励方式,优化选取适合厚壁管道检测的0.5MHz探头和楔形块角度为60°的斜探头组合.通过改变斜探头与外壁轴向缺陷之间周向距离,在一定范围内仍可检测到缺陷回波,且接收到的周向回波幅值变化不大,表明周向导波...     

Bruch’s-Mimetic Nanofibrous Membranes Functionalized with the Integrin-Binding Peptides as a Promising Approach for Human Retinal Pigment Epithelium Cell Transplantation

Background: This study aimed to develop an ultrathin nanofibrous membrane able to, firstly, mimic the natural fibrous architecture of human Bruch’s membrane (BM) and, secondly, promote survival of retinal pigment epithelial (RPE) cells after surface functionalization of fibrous membranes. Methods: Integrin-binding peptides (IBPs) that specifically interact with appropriate adhesion receptors on RPEs were immobilized on Bruch’s-mimetic membranes to promote coverage of RPEs. Surface morphologies, Fourier-transform infrared spectroscopy spectra, contact angle analysis, Alamar Blue assay, live/dead assay, immunofluorescence staining, and scanning electron microscopy were used to evaluate the outcome. Results: Results showed that coated membranes maintained the original morphology of nanofibers. After coating with IBPs, the water contact angle of the membrane surfaces varied from 92.38 ± 0.67 degrees to 20.16 ± 0.81 degrees. RPE cells seeded on IBP-coated membranes showed the highest viability at all time points (Day 1, p < 0.05; Day 3, p < 0.01; Days 7 and 14, p < 0.001). The proliferation rate of RPE cells on uncoated poly(ε-caprolactone) (PCL) membranes was significantly lower than that of IBP-coated membranes (p < 0.001). SEM images showed a well-organized hexa/polygonal monolayer of RPE cells on IBP-coated membranes. RPE cells proliferated rapidly, contacted, and became confluent. RPE cells formed a tight adhesion with nanofibers under high-magnification SEM. Our findings confirmed that the IBP-coated PCL membrane improved the attachment, proliferation, and viability of RPE cells. In addition, in this study, we used serum-free culture for RPE cells and short IBPs without immunogenicity to prevent graft rejection and immunogenicity during transplantation. Conclusions: These results indicated that the biomimic BM-IBP-RPE nanofibrous graft might be a new, practicable approach to increase the success rate of RPE cell transplantation.     

The Alleviating Effect of Lagerstroemia indica Flower Extract on Stretch Marks through Regulation of Mast Cells

Striae distensae (SD) or stretch marks are common linear scars of atrophic skin with disintegrating extracellular matrix (ECM) structures. Although fibroblasts contribute to the construction of ECM structure in SD, some studies have reported that mast cell degranulation causes the disruption of ECM in early SD lesions. Lagerstroemia indica flower (LIF) has traditionally been used in India as a diuretic. However, little is known about the effect and molecular action of Lagerstroemia indica flower extract (LIFE) on alleviating SD. This study evaluated the effects of LIFE on mast cell degranulation and the synthesis of ECM components in fibroblasts. LIFE inhibits the adhesion of rat basophilic leukemia (RBL) cells, RBL-2H3 on fibronectin (FN) and the expression of integrin, a receptor for FN, thereby reducing focal adhesion kinase (FAK) phosphorylation. In addition, LIFE attenuated the allergen-induced granules and cytokine interleukin 3 (IL-3) through the adhesion with FN. Moreover, the conditioned medium (CM) of activated mast cells decreases the synthesis of ECM components, and LIFE restores the abnormal expressions induced by activated mast cells. These results demonstrate that LIFE suppresses FN-induced mast cell activation and promotes the synthesis of ECM components in fibroblast, which indicates that LIFE may be a useful cosmetic agent for SD treatment.     

具扰动项的L—R型迁移方程的谱问题

本文在Lp（1≤P〈＋∞）空间上,研究了种群细胞增生中一类具扰动项的L—R模型,证明了这类模型相应的迁移算子生成半群的Dyson—Phillips展式的9阶余项R9（t）在L1空间上是弱紧和在Lp（1〈P〈＋∞）空间上是紧的,从而获得了该迁移算子的谱在右半平面上仅由有限个具有限代数重数的离散本征值组成及该迁移方程解的渐近稳定性等结果．     

飞秒激光在细胞纳米手术中的应用

激光类型不同,其与生物组织的作用机理也不同。其中飞秒激光由于脉冲持续时间短、瞬时功率大、聚焦尺寸小的特点,使得其在超快、超强和超精细领域有着广阔的应用前景。而结构微小的细胞的动力学研究,如有丝分裂、变形和凋亡,对于了解细胞的生物和发育行为有着重要作用。且生物大分子和水几乎不吸收近红外波长的光,故考虑应用近红外飞秒激光对细胞进行手术。这种激光手术技术已用于对细胞内结构进行切割和蚀除。介绍了该技术在细胞领域中的一些应用,如纳米手术、基因转染和染色体切割等。与传统技术相比,该技术精度高,可在不损伤细胞活性的前提下对细胞进行实验。     

SrTiO3/α-Fe2O3异质结光阳极光电转换性能

作为一类重要的光电极材料,α-Fe2O3在太阳能转化方面有着潜在的应用前景.但是,光生电子空穴对的再复合导致α-Fe2O3的光电量子产率很低.为了抑制光生电子空穴对的再复合,提高α-Fe2O3的光电量子产率,采用Spin-coating方法在透明导电玻璃FTO(SnO2:F)衬底上制备了SrTiO3/α-Fe2O3异质结薄膜光电极,并对该光电极进行了XRD、SEM、紫外-可见透射光谱的表征.在三电极光电化学测试系统中对薄膜的光电流-电压特性、入射光子电流转化效率(Incident photon to current efficiency,IPCE)对波长的依赖性进行了表征.在相同的Xe灯照射条件下,SrTiO3/α-Fe2O3异质结光电极的光电流及IPCE值大于单一的SrTiO3、α-Fe2O3各自的光电流及IPCE值,这与理论预测的结论一致.