“高温热结构复合材料”课程教学改革与实践研究

在高校专业课中实施课程教学改革是高等教育实现全员全程全方位育人的重要组成部分。以“高温热结构复合材料”课程为研究对象,分析了目前课程教学中存在的“课程理论知识与工程实践结合不紧密”和“课程教学内容与思政教育的融合性不充分”等问题。针对教学问题开展了课程教学改革与实践,提出了“高温热结构复合材料”课程内容设计方法,阐明了“高温热结构复合材料”课程思政设计思路。最后,结合“高温热结构复合材料”课程教学改革的实施过程和学生的反馈,总结了课程教学改革的实施效果。

如何破解活动区材料高结构化的困局

部分幼儿园活动区材料倾向服务于学习性活动、目标指向性强、操作方法较单一的高结构材料,不能充分满足幼儿游戏及探索的需要,无法引发幼儿多种探索行为。研究和实践发现,通过将部分高结构材料转化为低结构材料、改变玩法、精心设计低结构材料、设计竞赛性游戏等策略,可以破解活动区材料高结构化的困局,使活动区材料更加适应幼儿学习和成长的需要。

材料结构性及投放方式对幼儿专注力的影响研究

专注力是幼儿关键的学习品质,在游戏中的专注力表现对幼儿学习品质的发展至关重要。因此,本研究以游戏结构材料为媒介,采用观察法和访谈法,选取合肥市某幼儿园中班三十五名幼儿作为研究对象,采用高、低不同结构游戏材料,并且分别采用不同的投放方式,研究幼儿专注力的表现。经研究表明,高结构游戏材料下不同投放方式幼儿专注力存在统计学意义上的差异,低结构游戏材料下不同投放方式幼儿专注力存在统计学意义上的差异,相同投放方式下高、低结构游戏材料幼儿专注力存在统计学意义上的差异。研究中还针对以上研究结果提出相应的建议,该研究为教师提高幼儿专注力,在进行游戏材料的选择和投放方面提供实践依据。

开发超级钢铁材料

从21世纪初起,高度工业化的日本将迎来大的转换期。这主要表现于:(1)人口在2010年左右开始缓慢地减少,2009年以后平均每5人当中就有1人是65岁以上的高龄者;(2)在五六十年代建成的主要基础设施已老化,大部分设施需要更新换代;(3)更新社会基础设施的经费在整个社会设施总投资额中占的比率将会不断增大。

Cobalt-free gadolinium-doped perovskite Gd_xBa_(1-x)FeO_(3-δ) as high-performance materials for oxygen separation

Cobalt-free oxides GdxBal-xFeO3-σas（0.01 _〈 x _〈 0.1 ） were achieved by a solid state reaction method. It is found that GdxBal-xFeO3-σas（0.025 _〈 x _〈 0.1） exhibits the cubic perovskite structure. Among GdxBal-xFeO3-σas （0.025 -〈 x -〈 0.1 ）, the GdxBal-xFeO3-σas （GBF2.5） membrane shows the outstanding phase structure stability and the highest oxygen permeation, which can reach 1.44 ml. cm- 2. rain- 1 at 950 ℃ under air/He oxygen partial pressure gradient. The GBF2.5 membrane was successfully operated for more than 100 h at 800 ℃ and the oxygen permeation flux through the membrane is 0.62 ml. cm- 2. rain- 1. After 100 h oxygen permeation experiment at 800℃, X-ray diffraction （XRD） and energy dispersive X-ray spectrometer （EDXS） demonstrate that the GBF2.5 exhibits phase structure stability even at intermediate temoerature.

Effects of RE and Sr additions on dendrite growth and phase precipitation in AZ91D magnesium alloy

To develop AZ91D alloys with fine microstructure, effects of the addition of rare earth (RE), Sr and RE + Sr on the dendrite growth and phase precipitation in AZ91D magnesium alloy were studied, respectively. The results show that the microstructure is refined and the morphology of β-Mg17A112 phase is modified with RE or Sr addition, especially with the RE+Sr composite addition which can reduce the average grain size of AZ91D alloy obviously to 141 μm. The needle-like or block-like new phases adhering to β-Mg17A112 phase form at interdendrites during solidification. The enrichment of RE or/and Sr elements in front of the solidification interface, especially at the tips of α-Mg dendrite, which restricts the growth of α-Mg dendrite, changes the preferential growth of α-Mg and finally results in the grain refinement and the blunting of α-Mg dendrite.

Design of the Composite Steel-Glass Beams with Semi-Rigid Polymer Adhesive Joint

New and high transparent structural element, steel-glass composite beam was developed in respect to fabrication, static-structural and architectural criteria and consists of steel flanges and glass web assembled together by semi-rigid polymer adhesive, which is the key element of whole composite system. These beams can be used mainly as members of high transparent roof or floor structure as well as stiffening fins for large area glass facades. This paper deals with experimental research performed at CTU （Czech Technical University） Prague, which started by adhesive selection and initial material tests by ISO527, continued via small-scale steel-glass connection tests and graduated by full-scale tests of hybrid beams with the span of 4 m. Generalized results of these experiments, analytical and numerical studies serve as device, how to accurately predict the behavior of the beam, describe the stress distribution along the cross section and safely and economically design such a kind of structure with semi-rigid shear connection, made by polymer adhesive.

RECENT ADVANCES IN THE PREPARATION OF MOLECULARLY IMPRINTED POLYMERS VIA CONTROLLED RADICAL POLYMERIZATION TECHNIQUES

Molecular imprinting technique is a simple and efficient method for the preparation of polymer materials (i.e., molecularly imprinted polymers, MIPs) with tailor-made recognition sites for certain target molecules. The resulting MIPs have proven to be versatile synthetic receptors due to their high specific recognition ability, favorable mechanical, thermal and chemical stability, and ease of preparation. Recent years have witnessed significant progress in the synthesis and applications of MIPs. This review focus on the recent developments and advances in the preparation of MIPs via various controlled radical polymerization techniques.

Microstructural study of the ablation behaviors of 3D fine weave pierced Carbon/Carbon composites using plasma torch at ultra-high temperature

A simple and effective method of testing ablation behaviors of carbon/carbon composites at high temperature was provided, which used plasma torch as the heater. The ablation resistance of 3D fine weave pierced carbon/carbon composites at high temperature was also studied. The results show that temperature of the plasma flame is very high which is much closer to the real work environment of carbon/carbon composites. The factors that affect the ablation characters of carbon/carbon composites depend on both the properties of their components and the environmental conditions in which the material is placed. The ablation behaviors of C/C composites change from the center flame region predominantly influenced by sublimation of graphite to the region close to the outer flame influenced mainly by oxidization of graphite. The sublimation ability of carbon matrix is equal to that of carbon fibers but the oxidization ability of carbon fibers is significantly enhanced compared to that of carbon matrix.

Preform-based toughening technology for RTMable high-temperature aerospace composites

This article describes the efforts that led to the development of surface-loaded preforms that may be used to significantly improve the compression-after-impact strength of high-temperature composites and correspondingly to dramatically reduce the area of damage because of impact.Moreover,by matching the toughening polymer surface-loaded and design of the surface pattern,in-plane mechanical properties are unaffected or even improved over laminates made from the identical materials.The proprietary preforms,so-called ESTM-Fabrics,may be handled and infused with the high-temperature RTMable resins such as bismaleimide and polyimide in exactly the same manner as traditional fabrics without surface modification.The RTM conditions for the preform-based toughening is fully compatible with the traditional process procedure,making the technology cost-effective in production.This technology represents a key enabler for the use of low-cost RTM processes for high-temperature resins to supplant prepreg as the building-block material of choice for aeronautical composite structures.

Improved multilevel storage capacity in Ge_(2)Sb_(2)Te_(5)-based phase-change memory using a high-aspect-ratio lateral structure

Further improvement of storage density is a key challenge for the application of phase-change memory(PCM)in storage-class memory.However,for PCM,storage density improvements include feature size scaling down and multilevel cell(MLC)operation,potentially causing thermal crosstalk issues and phase separation issues,respectively.To address these challenges,we propose a high-aspect-ratio(25:1)lateral nanowire(NW)PCM device with conventional chalcogenide Ge_(2)Sb_(2)Te_(5)(GST-225)to realize stable MLC operations,i.e.,low intra-and inter-cell variability and low resistance drift(coefficient=0.009).The improved MLC performance is attributed to the high aspect ratio,which enables precise control of the amorphous region because of sidewall confinement,as confirmed by transmission electron microscopy analysis.In summary,the NW devices provide guidance for the design of future high-aspect-ratio threedimensional PCM devices with MLC capability.

Heterometallic copper(Ⅱ) vanadates: synthesis, crystal structures and third-order nonlinear optical properties

Three polymeric heterometallic clusters with 1D, 2D, and 3D frameworks, constructed from a cyclic vanadate {V4O12}4- building block and three geometric constraint ligands, were synthesized by a one-pot self-assembly reaction. Z-scan experiments demonstrated that all the three cluster polymers have large hyperpolarizability y values. TD-DFT calculations afforded insight into the electronic transitions and spectral characterization of these novel NLO molecular materials.

E-beam-induced in situ structural transformation in one-dimensional nanomaterials

Electron beam （e-beam） irradiation is an inev- itable, but crucial issue for electron microscopy. Our investigation results show the e-beam-induced in situ structural transformations in silicon （Si） nanowires and zinc oxide （ZnO） nanowires （NWs）, respectively. Crystal to amorphous structure transition was revealed in Si NWs utilizing high resolution electron microscopy and electron energy loss spectroscopy. Reconstruction at the （1010） surface of ZnO NWs was also observed in the transmission electron microscope （TEM） using aberration-corrected electron microscopy. These e-beam-induced in situ struc- tural transformations prove that the electron beam irradi- ation effect is able to be used for the local modification of one-dimensional nanomaterials.