Generating dynamic crack growth resistance curves for fiber-reinforced concrete

Fiber-reinforced concrete is known to have a greater resistance to impact and impulsively applied loads than its plain counterpart. However, the exact mechanisms that contribute to this enhanced resistance are not known, and fundamental fracture tests are necessary to develop such an understanding. To this end, an instrumented drop weight impact machine was configured to perform dynamic fracture studies on fiber-reinforced concrete specimens. Cracks were allowed to open in Mode I under high rates of loading using contoured double cantilever beam specimens. The paper describes the test apparatus, instrumentation, calibration, and the data analysis. The technique was applied to investigate dynamic crack growth in two types of fiber-reinforced concrete composites: one with steel macrofiber and the other with polypropylene macrofiber. Companion tests were performed under quasi-static conditions. Test data indicate that the proposed technique can be successfully applied to study dynamic crack growth in cement-based composites and to further enhance their properties.     

Growth and properties of diamond-like films deposited from cyclohexane-argon mixtures in low-temperature plasma

The deposition of diamond-like films on polymer substrates from low-temperature cyclohexane-argon plasma was studied. The deposition rate was found to be proportional to the mass flow rate of cyclohexane vapor and independent of the mass flow rate of argon. The microhardness of the films and the light absorption coefficient in the blue spectral region depend on the ratio between the deposition rate and ion current density.Deceased in 1996.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2419–2421, October, 1996.     

二次硬化马氏体时效钢中纳米级强化相的分析

本文采用电化学相分析法确定它是一种Ｍ２Ｃ型碳化物，并利用两种溶液的联合处理法克服了在碳化物间相分离时复合合金化的碳化物（Ｆｅ，Ｃｒ，Ｍｏ）２Ｃ中元素间的选择性溶出，提高了相分析的准确度。     

沉积在液相基底表面磁性薄膜的形成机理和特性研究

采用气相沉积方法在硅油基底表面成功制备了一种具有近似自由支撑的新型铁薄膜系统，并研究了其生长机制、内应力分布以及低温磁特性．实验发现，此类铁薄膜的生长机制与沉积在液相基底表面非磁性薄膜的情况类似，即服从二阶段生长模型．在固定基底温度的条件下，当沉积速率较小时，可制得近似透明的连续铁薄膜，薄膜中呈现明显的特征尺寸达10^2μm数量级的带状准周期有序结构，它是由铁薄膜样品中内应力释放时所引起的薄膜板块间相互挤压而逐渐形成的．当沉积速率较大时，制得的连续铁薄膜呈金属色．实验发现，在临界温度Tc=10—15K附近，具有金属色的铁薄膜样品的矫顽力Hc有一明显的极大值峰．研究表明，这一奇异的矫顽力特性与液相基底表面铁薄膜中的原子团簇尺寸分布、无序的薄膜表面磁各向异性以及团簇间的磁性相互作用等因素有关．     

Characterization of ZnO: Al films deposited by r.f. magnetron-sputtering at low temperature

Transparent conducting ZnO: Al thin films with good adhesion and low resistivity have been prepared on organic substrates and Corning 7059 glass substrates by r.f. magnetron-sputtering technique at low substrate temperature (25–210°C). Structural and photoelectric properties of the deposited films are investigated. The deposited films are polycrystalline with hexagonal structure and a preferred orientation with the c-axis perpendicular to the substrate. Only the (002) peak is observed. High quality films with resistivity as low as 1.0 x 10^-3Ω·cm and 8.4 x 10^-4Ω·cm, the average transmittance over 74% and 85% in the wavelength range of the visible spectrum have been obtained on different substrates.     

不锈钢辐射损伤随温度和剂量的变化(英文)

用重离子辐照模拟和正电子湮没寿命技术研究了改进型316L不锈钢在21 和33 dpa辐照剂量下的辐照损伤在室温到802 °C温度范围随辐照温度变化和室温下0—100 dpa剂量范围随辐照剂量变化. 在580 °C左右实验观察到辐照肿胀峰， 在21 和33 dpa辐照剂量下相应的空位团分别由14和19个空位组成， 尺度分别为0.68 和0.82 nm. 空位团尺寸随辐照剂量增加， 在100 dpa时空位团由8个空位组成， 尺度为0.55 nm. 实验结果表明， 在改进型316L不锈钢中辐照损伤随辐照温度变化更灵敏.     

砖砌体房屋抽墙加固方案

某砖砌体房屋因功能改变而需要更大的使用空间，部分承重墙体的抽除导致传力途径的改变，进而需要对原有构件进行改造或加固．本方案针对其各部分具体情况的差异，分别采用了混凝土增大截面，并外包角钢加固柱、墙顶增设承重梁拉预应力螺杆加固承重墙底圈梁等方法，对原结构进行了局部加固．加固后5年多的使用表明加固效果良好．     

稀土在石油套管钢中的应用研究

稀土在Ｊ－５５钢级套管钢中有净化钢液，变质夹杂和微合金化作用，提高了钢的横向冲击值和抗裂纹扩展能力，显著改善了抗射孔开裂性能。稀土变质ＭｎＳ和Ａｌ２Ｏ３夹杂的程度，分别取决于钢中稀土与锰和稀土与铝的活度比值，而活度比值决定了钢中ＲＥＡｌＯ３和ＲＥ２Ｏ２Ｓ的相对数量和性能。     

稀土对管线钢中沉淀相和再结晶的影响

管线钢中含有Ｎｄ，Ｔｉ复合的沉淀相，表示为（Ｎｂ，Ｔｉ）（Ｃ，Ｎ）。添加稀土的锻态样中，沉淀物颗粒细化，球化且弥散分布。随着稀土量增加，沉淀物中Ｎｂ量也略增加。在奥氏体化温度下，稀土使沉淀相析出的孕育期延长，沉淀速率降低，抑制了沉淀相的析出动力学过程。     

Reliable Polymer-Stabilized Ferroelectric Liquid Crystal Device Using Thin Plastic Substrates

We developed a rollable polymer-stabilized ferroelectric liquid crystal (FLC) display device using thin plastic substrates. In a device using 200-μm-thick substrates which are fastened by polymer walls and networks made by photopolymerization-induced phase separation, disorder of the FLC alignment was caused by exfoliation of these walls in curvature radii of under 30 mm. Otherwise, the uniformity of the FLC alignment was maintained even after a device using 100-μm-thick substrates was bent at a radius of 7 mm. The enhanced bending tolerance does not depend on the FLC alignment direction, and the device could be bent both convexly and concavely without any FLC alignment change. A rollable device with a size of 100 × 100 mm exhibited uniform grayscale display operation between crossed polarizers when bent with a radius of 15 mm.