Processing of Yttria-Alumina Coated Silicon Nitride Slips by Slip Casting

Si₃N₄powders coated with 6 wt% Y₂O₃and 4 wt% Al₂O₃were prepared by coprecipitation. The resulting powders were dispersed in water at different pH values and with addition of various amounts of ammonium polyacrylate (NH₄PA) to produce 32 vol% slips. The influence of the amount of NH₄PA solution added and pH on the rheological properties of 32 vol% coated Si₃N₄slips were studied. In addition, the sintered density of cast samples was determined and related to the degree of slip dispersion. The adsorption of the NH₄PA on the coated particle surface was rather high and the surface became saturated near 0.86 mg/m²at pH 9.2. High NH₄PA concentrations (1.7–3 wt%) were necessary to obtain well dispersed 32 vol% coated Si₃N₄slips at pH 9.2. The best stabilization was obtained with the addition of 2.3 wt% NH₄PA; in this condition, the viscosity reached a minimum value of 35 mPa.s at 100 s^–1. The slip viscosity increased with increasing pH from 9.2 to 10.2. Slips with low viscosities gave a more dense packing of cast samples and consequently higher sintered density values.     

Pullout tests of epoxy-coated reinforcement in concrete

The bond strength and slip of epoxy-coated reinforcing bars in concrete have been evaluated by carrying out single pullout and double pullout tests. In extended single pullout tests, slip measurements were made while tensile force was applied to reinforcing bars embedded in concrete. In double pullout tests, 20 cycles of load were applied at levels of steel stress between zero and 0·5 times characteristic steel strength. Strains were measured by electrical resistance strain gauges glued inside the bars. Both epoxy-coated and uncoated bars were used in the investigation, to obtain comparative results. The strain gradient along the bar was found to be less for the coated reinforcement. In general, the epoxy coating was found to increase slip in bond and thereby reduce the bond performance of coated bars.     

Characterization of the flow behaviour of sausage emulsions with a simple tube viscometer

A specially designed tube viscometer was used to measure apparent viscosity during flow of Bologna type sausage emulsions moving through a pipe. Emulsions varied in fat content (from 21.8 to 44.3%) and in moisture/protein ratio (from 3.7 to 5.6), and the effects of added sodium chloride, sodium diphosphate, starch and blood plasma were investigated in a 36% fat, 3.7 moisture/protein emulsion.
The shear stresses determined as a function of shear rate were fitted by a power law. Yield stress of the emulsions was negligible relative to the applied stress. However, inspection of the flow profiles indicated that considerable slip of the sausage emulsion occurred at the pipe wall. Both emulsion flow and slip contribute to overall flow behaviour, so a kind of effective viscosity is determined. Intrinsic rheological properties and wall slip will both be affected by the composition of the sausage emulsion.     

垂直井两相流动生产测井解释滑动模型

在两相流动模拟实验数据分析的基础上 ,提出油水两相和气液两相流动的滑脱速度的实验关系 ,进而确定垂直井两相流动生产测井解释的滑动模型。现场实际测井资料处理结果表明该模型有很好的应用效果     

双滑移取向Cu单晶的循环形变行为──Ⅱ．滑移带和形变带SCIEI

用光学显微镜和扫描电镜研究了双滑移取向（［０３４］，［１１７］）Ｃｕ单晶循环饱和后的表面形貌，塑性分切应变幅（γｐｌ）低于１０^（－３）时，［０３４］晶体表面上要为主滑移系的驻留滑移带（ＰＳＢｓ）占据，次滑移只在边缘区域启动，其ＰＳＢｓ细窄（＜１μｍ），体积百分数在１％以下．γｐｌ＞１０^（－３）时，次滑移开始在试样的中部启动，同时，表面出现二种贯穿晶体的宏观形变带（ＤＢＩ，ＤＢＩＩ），滑移带在形变带内集中．［１１７］晶体在γｐｌ＝４．４×１０^（－４）时，双滑移现象已十分明显．γｐｌ＞１０^（－３）时，表面也形成与前者相似的形变带．ＤＢＩ的惯习面与主滑移面平行（［０３４］晶体）或接近（［１１７］晶体），ＤＢＩＩ的惯习面则与前者垂直，文章讨论了形变带形成的可能原因．     

钢球纵轧成形后滑的研究

基于钢球坯纵轧成形工艺,应用弹塑性有限元法,建立了钢球坯连轧成形的实体模型;模拟了轧件在成形过程中的速度场;通过实验研究了后滑的存在及其影响因素。     

滑坡面位移特征及其应用

论述了滑坡坡面位移特征，提出了根据坡面位移矢量确定滑坡滑动面、预报滑坡发生时间的原理和方法。     

卵磷脂改善泥浆性能的研究

研究了卵磷脂改善泥浆性能的作用。通过在一定含水量的泥浆中，比较加入卵磷脂前与加入卵磷脂后的泥浆性能，以及比较加入不同系列型号的卵磷脂问的泥浆性能，得到卵磷脂对泥浆性能的影响，从而优化出改善泥料性能的卵磷脂的种类与用量。     

Numerical simulation of electroosmotic flow in hydrophobic microchannels

Electroosmotic flow (EOF) is a promising way for driving and mixing fluids in microfluidics. For the parallel-plate microchannel with the hydrophobic surface, this paper solved the governing equations using the finite element method (FEM), and the effects of microchannel height, electric strength and ionic concentration on EOF were thus investigated. The simulation indicates that the transient characteristics of EOF are similar in hydrophobic and hydrophilic microchannels, the steady time of EOF is proportional to the square of microchannel height, and the scale is microsecond. EOF velocity is proportional to the electric strength and independent of the channel height, and decreases slowly with the ionic concentration, which is lower than that in hydrophilic microchannel due to the presence of slip length in hydrophobic microchannel. The results can provide valuable insights into the optimal design of microchannel surfaces to achieve accurate EOF control in hydrophobic microchannel. Supported by the National Natural Science Foundation of China (Grant No. 50730007)