Portability of three consumer products

Three consumer products (a television set, a personal computer and a typewriter), all considered portable by their respective manufacturers, were evaluated experimentally for portability. Products were not considered portable if the physical and subjective workloads resulting from carrying them over specified distances were excessive. Twenty-two males and six females participated in the experimental investigation and carried the three products for distances of 45·72, 91·44. 137·16 and 182·88 m. Their pulse and ratings of perceived exertion (RPE) of the arms and whole body were recorded and used as measures of physical and perceived workloads. Both physiological and subjective responses to carrying products were significantly influenced by the type of product and carrying distance, regardless of the gender of the person performing the carrying. The results of this study and the design guidelines provided in the literature for one-handed and two-handed carrying tasks led to the conclusion that, of the three products, only the television set could be considered portable.     

Finite-size effects in surface tension: Thermodynamics and the Gaussian interface model

It has been suggested by Kayser that finite-size effects associated with capillary waves might play a significant role in some surface tension measurements; for capillary rise between plates a distance D apart, an effect varying as 1/D and apparently observable in measurements, was proposed. In reconsidering this problem, one must analyze the thermodynamics of finite-size corrections to surface tension. In particular, one sees that capillary rise between plates does not measure the interfacial free energy density but, rather, a derivative of the interfacial free energy with respect to a system dimension. The quantity needed to draw definite conclusions, the finite-size residual free energy, can be calculated within the harmonic or Gaussian capillary wave model in d spatial dimensions with the aid of Poisson summation techniques and should yield the correct leading asymptotic behavior. For d=3 and experimentally relevant parameter values, the results are independent of the short-wavelength cutoff needed in the model and can be checked against the theory of conformai covariance at two-dimensional critical points. It is found that the finite-size effects in capillary-rise measurements of surface tension vary as 1/D ² (with a universal coefficient) but are too small to be seen in current experiments.Invited paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

金选别工艺的发展与深化

本文阐述了充分考虑矿石性质,探索出混合浮选的分步流程,恰当的施用多元扑收剂所产出的“协同效应”,稳定和强化选别工艺,收到提高选金技术指标的效果。     

The Interaction of Glymes with Surfactant Micelles

The critical micelle concentrations (CMC) values and counterion dissociation (α values) have been determined for a number of mixed micellar systems consisting of two typical ionic surfactants and glycol ethers (glymes) as cosurfactants, namely diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether. Conductance experiments were used to determine the CMC and α values of the mixed micelles as a function of glyme concentration in the aqueous mixed solvent. Favorable interactions between sodium dodecyl sulfate micelles and glyme cosurfactants were deduced from the decreases in the CMC values and the large increase in the α values of these systems as a function of increasing glyme concentration in the mixed solvents. In contrast to the anionic surfactant/glyme systems, in general, there appeared to be little favorable interactions between the surfactant and glymes when micelles of the cationic surfactant dodecyltrimethylammonium bromide were formed in water/glyme solvent systems containing an increasing amount of the glymes. The interaction of glymes with the surfactant micelles was examined closely via ¹³C nuclear magnetic resonance (NMR) chemical shifts for both surfactant and glyme carbons; these chemical shifts changes were interpreted in terms of the distribution and the localization of the glymes in the aggregates. Finally, partition constants, determined from two-dimensional diffusion-oriented spectroscopy (2D-DOSY) experiments, were used to calculate thermodynamic quantities of transfer of the glymes between the bulk phase and the self-assembled aggregates. All these results are interpreted in terms of the key contributions that both the glyme ethoxylated groups and alkyl endgroups make to the hydrophobic interactions.     

Apoptotic Effects of Anthocyanins from Vitis coignetiae Pulliat Are Enhanced by Augmented Enhancer of the Rudimentary Homolog (ERH) in Human Gastric Carcinoma MKN28 Cells

Evidence suggests that augmented expression of a certain gene can influence the efficacy of targeted and conventional chemotherapies. Here, we tested whether the high expression of enhancer of the rudimentary homolog (ERH), which serves as a prognostic factor in some cancers, can influence the efficacy of anthocyanins isolated from fruits of Vitis coignetiae Pulliat, Meoru in Korea (AIMs) on human gastric cancer cells. The anticancer efficacy of AIMs was augmented in ERH-transfected MKN28 cells (E-MKN28 cells). Molecularly, ERH augmented AIM-induced caspase-dependent apoptosis by activating caspase-3 and -9. The ERH-augmented apoptotic effect was related to mitochondrial depolarization and inhibition of antiapoptotic proteins, XIAP, and Bcl-2. In addition, reactive oxygen species (ROS) generation was augmented in AIMs-treated E-MKN28 cells compared to AIMs-treated naïve MKN28 cells. In conclusion, ERH augmented AIM-induced caspase-dependent mitochondrial-related apoptosis in MKN28 cells. A decrease in expression of Bcl-2 and subsequent excessive ROS generation would be the mechanism for ERH-augmented mitochondrial-related apoptosis in AIMs-treated MKN28 cells. A decrease in expression of XIAP would be another mechanism for ERH-augmented caspase-dependent apoptosis in AIMs-treated MKN28 cells.     

Boron Nitride Nanosheets Strengthened PVA/Borax Hydrogels with Highly Efficient Self-Healing and Rapid pH-Driven Shape Memory Effect

Self-healing hydrogels often possess poor mechanical properties which largely limits their applications in many fields. In this work, boron nitride nanosheets are introduced into a network of the poly(vinyl alcohol)/borax (PVA/borax) hydrogels to enhance the mechanical properties of the hydrogel without compromising the self-healing abilities. The obtained hydrogels exhibit excellent mechanical properties with a tensile strength of 0.410 ± 0.007 MPa, an elongation at break of 1712%, a Young's Modulus of 0.860 ± 0.023 MPa, and a toughness of 3.860 ± 0.075 MJ m⁻³. In addition, the self-healing efficiency of the hydrogels is higher than 90% within 10 min at room temperature. Benefiting from the excellent self-healing properties, the shapeability of the hydrogel fragments is observed using different molds. In addition, the hydrogels display rapid pH-driven shape memory effects and can recover to their original shape within 260 s. Overall, this work provides a new approach to hydrogels with integrated excellent mechanical properties, self-healing abilities, and rapid pH-driven shape memory effects.     

多元高铬铸铁在反击式破碎机板锤上的应用

在高铬铸铁中加入多种少量和微量合金元素用以生产反击式破碎机板锤，可使产品耐磨性和综合力学性能得到很大程度的改善。使用寿命比原用高锰钢提高4倍以上。     

650轧机用重型减速机使用实践与分析

本文针对我厂650×3中型轧钢机用主减速机当前的工作条件和轧制负荷情况,该减速机的设计特点、传动布置力学原则、使用维护经验等几个方面进行系统分析,并结合其运动现状和工作情况趋向,以探讨该减速机良好的工作可靠性和长期使用寿命的成因。     

基于Visual Basic 开发机床主传动非常规变速系统的设计--重复转速的传动系统(实例之二)

本文介绍利用Visual Basic工具开发金属切削机床主传动非常规变速系统的设计总体结构，功能和方法，以重复转速的传动系统为例，重点介绍转速图的拟定过程，本系统具有界面美观，操作方便，易于理解的特点。     

有芯工频炉酸性炉衬对生产欧元材料的影响

通过对有芯工频炉酸性炉衬生产欧元材料出现的问题进行分析，发现在使用有芯工频炉酸性耐火材料时，炉衬寿命大大缩短，并使铜液Si含量超标，造成材料报废。而炉衬材料换成中性耐火材料时，基本上控制了Si含量，达到了欧元材料标准，并使炉衬寿命大大提高。