Study on morphologies of Co microcrystals produced by solvothermal method with different solvents

Cobalt microcrystals with different sizes and morphologies were fabricated via a facile solvothermal method. The effects of different solvents on the sizes and morphologies are investigated separately. Flowerlike cobalt with around tens of microns in diameter is obtained in ethanol. Meanwhile, of microdisks and octadecahedra with the edge lengths about several microns are fabricated in ethylene glycol and glycerol, respectively. Reduction potential and viscosity rank of the solvents play the important roles in controlling the sizes and morphologies of cobalt. Moreover, room-temperature magnetic measurement shows that the magnetic properties of cobalt microcrystals depend on their morphologies.     

β-tricalcium phosphate nanoparticles adhered carbon nanofibrous membrane for human osteoblasts cell culture

β-tricalcium phosphate nanoparticles adhered carbon nanofibrous (β-TCP@CNFs) membranes were prepared by electrospinning and sintering a mixed solution of triethylphosphate, calcium nitrate tetrahydrate, and PAN. Crystalline structure and morphology of β-TCP@CNFs were characterized by XRD, SEM, and TEM observations. The diameter of the β-TCP nanoparticles was in the range of 30-60 nm, they were well distributed on the surface of CNFs. Human osteoblasts cells were actively proliferated on the β-TCP@CNFs membrane due to the far extended adhesion area and biocompatibility.     

Effective Hybrid/Mixed Finite Elements for Folded-Plate Structures

A new formulation in which the assumed stress field is divided into membrane and bending stress fields is developed. A family of effective shell elements of hybrid/mixed finite element method that accounts for transverse shear deformations is proposed based on a modified Hellinger–Reissner variational principle. In this paper, the present shell elements possess different three-field assumptions, which are described by compatible displacement, incompatible displacement, and stress fields. Several benchmark problems are conducted to test both the accuracy and reliability of the proposed shell elements. Numerical analyses show that the present shell elements pass all the patch tests, do not contain any spurious zero energy modes, and have no lock phenomena even for very thin plate and shell. Further insight into the performance of the present shell elements is gained to demonstrate the high accuracy of the elements by several folded-plate structure problems. The numerical results demonstrate the validity, reliability, and applicability of the present elements. The present elements are valid for thick as well as thin shell structures.     

汽车半轴摩擦焊接头焊后热处理工艺及强韧性能的控制

研究了ＳＸ１１０型汽车半轴摩擦焊接头的焊后热处理工艺对其强性能的控制作用，并对热处理规范参数进行了优化。台架试验结果表明：用锻造－摩擦焊接复合工艺生产的ＳＸ１１０型汽车半轴摩擦焊接头的强韧化水平达到和超过了整体锻造半轴的强韧化水平。     

In situ AFM study of the growth of banded hedritic structures in thin films of isotactic polystyrene

The growth of banded hedrites of isotactic polystyrene (iPS) is followed in situ, using atomic force microscopy (AFM). The melt layer surrounding the growing hedritic front is much thinner than both the hedrite front and the far-field melt. Growth occurs simultaneously in three dimensions: radially, circumferentially and height. The height of the hedrite growth front being so much higher than the adjacent molten pool, the observed propagation of the front requires that it be covered by a thin film of molten material, likely drawn up the face of the front by capillarity. As the hedritic front grows in height, it demands material at a higher rate than can be delivered from the far-field melt and the stacked lamellae stop growing, layer by layer, from the top downward, until only the basal lamella continues to grow (at a constant velocity). The kinetics of the position of the lowest point ahead of the growth front slows with time during this process. Supplying only the basal layer, the adjacent molten pool is replenished and now begins to feed new layers of growing lamellae as the process repeats itself. The creation of the new lamellar layers appears to be coupled to morphological instability of the basal layer, in the form of growth front serrations, likely causal of the giant screw dislocations.     

幼儿教育新理念影响下的现代幼儿园建筑设计初探

随着社会的发展，经济水平的大幅度提高，幼儿教育也越来越受到家长及社会的关注。幼儿教育开始了一种新的教育理念，幼儿园建筑设计也需要进行创新，以便打破现有的僵化模式，创造一种灵活多变，满足现代幼儿园教育要求的建筑形式。本文针对当前我国幼儿园建筑与现代幼儿园教育理念不相适应的状况，探讨开放式现代幼儿园建筑设计的模式。     

Preparation and application of zeolite beta with super-low SiO<Subscript>2</Subscript>/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> ratio

This paper presents the direct synthesis of super-low SiO₂/Al₂O₃ ratio zeolite beta molecular sieve through a novel route, by which some of aluminium species are added during crystaling process. The IR results show that with the increase of aluminium content in the framework, the frequency of the band in the range of framework vibration (1060–1090 cm⁻¹) shifts to the lower wave-number; the BET surface-area decreases and the basicity of zeolite becomes stronger. In a second step, new adsorbents were obtained by solid-state ion exchanging zeolite beta with Cu(I), Ag(I) cations. The deep-desulfurization (sulfur levels of <1 ppmw) tests were performed using fixed-bed adsorption technique, the sulfur content of the treated and untreated gasoline was analyzed by microcoulometry. The experimental results show that the desulfurization performance of sorbents decreases in order: Cu(I)beta > Ag(I)beta > Na-beta. The best sorbent, Cu(I)beta, has breakthrough adsorption capacities of 0.236 mmolS/g of sorbent for model gasoline.     

Numerical simulation and experimental investigation on densification,shape deformation,and stress distribution of Ti6Al4V compacts during hot isostatic pressing

Hot isostatic pressing of metal powders involves a complex thermal and mechanical coupling process. A constitutive model based on Perzyna’s elastic-viscoplasticity equation was proposed, and a Lagrangian finite element method was applied to analyze the large deformation, nonlinear friction, powder flow, and densification behavior during hot isostatic pressing. The mechanical behavior of the powders was analyzed in terms of stress distribution. For comparison to the simulation results, the density, shape deformation, and residual stress of the specimens were evaluated using Archimedes’ principle, 3D measuring technology, and Empyrean X-ray diffractometer.     

三门峡水电站电气改造中三卷变压器的选择

水电站电气设计中，三卷变压器的最大阻抗放在高-中侧还是高-低侧，对中、低压侧的短路容量、高压系统的稳定影响、继电保护及供电的电压水平等都有很大影响，必须全面综合地考虑这些因素，并抓住对工程起决定性作用的因素作为选择的判据，这样才能获得最大的效益。三门峡水电站电气改造中220kV三卷变压器的选择就是一个具体的实例。