RYD-N型橡胶国际硬度计的研制

介绍新研制的RYD-N型橡胶国际硬度计的工作原理、设计特点及使用性能。该硬度计采用高硬度合金钢球面压头、两段定负荷加载,操作方便,测试精度高和稳定性好,达到同类硬度计世界先进水平,为橡胶硬度测试提供了一种新型仪器。     

用超低橡胶硬度计(VLRH)测定定负荷下硫化橡胶或热塑性橡胶的硬度

详细介绍了用超低橡胶硬度计(VLRH)测定定负荷下硫化橡胶或热塑性橡胶的硬度的方法。     

硬度计压头形状和负荷的大小对显微硬度的影响

硬度是衡量超硬材料烧结体的主要特性之一.然而目前国内外还没有超硬材料烧结体硬度测量的统一的标准.文章通过硬度计测量标准块的硬度值总结如下:施加相同力而采用不同形状的压头所得结果不同,采用相同的压头而施加不同的力所得结果也不一样;随着施加负荷的增大,压痕周围产生的破碎形变也在增大,这将影响测量值的准确性.因此,压头的形状和所施加的负荷是影响硬度值的一个重要因素.通过分析得知,在测试中应采用努普压头并且施加小负荷的力.[1,3]     

水中总硬度对氨氮测定的影响

通过长期的调查与实践,已经取得了较为显著的成效,为我国工业企业的废水处理提供了许多有价值的参考数据。然而,对于水中氨氮值的检测结果,受到其硬度影响较大。为了保证结果的准确性,首先应当通过实验找出水中总硬度对检测结果产生的影响以及规避方式。首先简单论述了水中氨氮值、硬度的相关理论,并集中分析了目前我国检测水中氨氮值时比较常用的几种方法,最后确定实验方式为分光光度法,并通过多次实验,总结水中总硬度对氨氮值检测存在的影响及其相应规律,希望能够对提升水中氨氮值检测的准确度有所帮助。     

测试条件对微孔橡胶垫板动刚度及动静比的影响

建立了微孔橡胶垫板结构简化模型,对动静比与能量损耗的关系进行了定性分析,并考察了测试频率和加载力值对动刚度和动静比的影响。结果表明,在外力作用下,橡胶垫板的内耗越大,则动刚度和动静比越大;随着测试频率和加载力值的增加,动刚度和动静比均增大。     

二段硫化条件对均聚氯醚橡胶(CO)性能的影响

研究了二段硫化条件(硫化温度和硫化时间)对均聚氯醚橡胶(CO)基本性能和压缩永久变形性能的影响。结果表明,二段硫化温度越高,硫化时间越长,胶料的拉伸强度和定伸应力越大,硬度越高;而撕裂强度、伸长率、拉断永久变形以及压缩永久变形越小,其中胶料的硬度、拉伸强度、伸长率、压缩永久变形在一定时间后基本上趋于平衡,较好的二段硫化条件为150℃～160℃×3～4h。     

二段硫化条件对丙烯酸酯橡胶性能的影响

研究二段硫化条件对活性氯型丙烯酸酯橡胶性能的影响。试验结果表明，二段硫化温度一定时，延长硫化时间可减小压缩永久变形，对力学性能、耐热性和耐油性影响不大；随着二段硫化时间的延长，硫化胶交联密度增大，尔后减小，再延长硫化时间，减小趋于平缓。     

热老化箱性能对橡胶试验结果的影响

选取2种典型的老化箱,分析了老化箱性能对热氧老化、恒压和耐液体试验结果的影响。结果表明,普通型老化箱对热老化试验结果有较大的影响,换气式老化箱可严格控制各项试验条件,对结果的影响较小;老化箱对高温恒压和耐液体试验结果的影响几乎可忽略。     

库仑法分析试样粒度对硫分测值的影响

研究了库仑法测硫分时,分析试样粒度对硫分测值的影响。结果表明,当0.2 mm筛上物占总试样10%以上时,造成测硫无显示。当煤试样为-0.1 mm时,测值偏低。因此,制样时应严格按照国家标准,保证试样粒度的均匀性,才能得到准确的硫分测值。     

搅拌热在苯甲酸发热量测试中的影响研究

为研究搅拌热在苯甲酸发热量测试中的影响,通过理论推导,得出搅拌热影响量近似计算公式,并进行了实例验证。研究表明,搅拌热发热量测试结果的影响与搅拌热、主期时间、试样质量相关。当搅拌热不参与计算时,表现出试样质量小则发热量偏高,试样质量大则发热量偏低。而当搅拌热参与计算时,得出的发热量测试结果无此明显现象。因此,搅拌热作为附加热参与计算有利于提高发热量测试结果的精密度和准确度。     

Influence of phase orientation on dynamic interfacial tension measured by drop volume tensiometry

In processes involving two liquid phases, such as enhanced oil recovery, one phase is often present in a drop form (drop phase) while the other is in continuous form (bulk phase). In the present paper, the effect of such phase orientation on dynamic interfacial tension between the two phases formed by the partially miscible system composed of butanol-1 and water has been investigated by using the method of drop volume tensiometry. With butanol-rich (butanol-1 saturated by water) as the drop phase and water-rich (water saturated by butanol-1) as the bulk phase, the interfacial tension is 1.70 ± 0.02 mN/m. The interfacial tension for water-rich as the drop phase is almost identical at 1.72 ± 0.03 mN/m. Addition of a surfactant, sodium dodecyl sulfate, to the system has been studied. When the surfactant is added to the drop phase (either butanol-rich or water-rich), the magnitude of the decrease in interfacial tension is smaller than when surfactant is added to the bulk phase (water-rich or butanol-rich) or to both phases. Under otherwise identical conditions, when the water-rich acts as the drop phase, the apparent interfacial tension is higher than that when the butanol-rich acts as the drop phase.     

Influence of cultural conditions on coal solubilization by Penicillium simplicissimum

Sub-bituminous coal, preoxidized with nitric acid and treated with sodium hydroxide solutions to obtain a water-soluble extract, was used for the study of coal degradation by Penicillium simplicissimum. The influence of different carbon and nitrogen sources was examined in connection with growth and production of acid-precipitable coal polymers. The yield was increased after the addition of maltose, lactose and cellobiose while glucose, fructose and xylose had little effect. An organic nitrogen source, yeast extract, was an improved source of nitrogen compared with ammonium chloride. The coal-degrading system appeared before the depletion of the carbon or nitrogen source. In addition, the effects of initial pH of the culture medium demonstrated an increase in the yield of coal polymers up to a pH of 7.5. Above this pH, non-biological catalysis increased gradually. However Ca²⁺ and Mn²⁺ increased the yield of coal polymers over a 14-day period, but yield was unaffected by Cu²⁺, Al³⁺ and Fe²⁺.     

Peel strength and peel angle measured by the T-peel test on Cr/BPDA-PDA interfaces

The peel strength and peel angle of Cr/BPDA-PDA interfaces were measured using the T-peel test for Cu/Cr/BPDA-PDA structures. When the Cu/Cr metal film was thin, plastic bending of the metal film occurred during the T-peel test. With a thicker metal film, however, plastic bending of BPDA-PDA polyimide was observed. The critical thickness of the metal film for the transition from metal film bending to polyimide bending became thinner with decreasing yield strength of the metal film. Regardless of the metal film bending or polyimide bending during the T-peel test, the peel strength increased with higher peel angle and the failure mode of the Cr/BPDA-PDA interfaces was cohesive failure within BPDA-PDA.     

Influence of diblock addition on tack in a polyacrylic triblock copolymer/tackifier system measured using a probe tack test

The influence of diblock copolymer addition on the tack properties of a polyacrylic triblock copolymer/tackifier system was investigated. For this purpose, poly(methyl methacrylate)‐block‐poly(n‐butyl acrylate)‐block‐poly(methyl methacrylate) triblock copolymer (MAM) and a 1/1 blend with a diblock copolymer consisting of the same components (MA) were used as base polymers, and a tackifier was added in amounts ranging from 10 to 30 wt %. The temperature dependence of tack was measured by a probe tack test. The tack of MAM/MA at room temperature was significantly higher than that of MAM, and the improvement of MAM/MA upon the addition of the tackifier was higher than that of MAM. The peeling process at the probe/adhesive interface during the probe tack test was observed using a high‐speed microscope. It was found that for MAM/MA, cavitation was caused in the entire adhesive layer, and peeling initiation was delayed by the absorption of strain energy due to deformation of the adhesive layer. In contrast, for MAM, peeling progressed linearly from the edge to the center of the probe. The greater flexibility of the soft block chain in the diblock copolymer resulted in improved interfacial adhesion. ¹H pulse nuclear magnetic resonance analysis showed that the addition of the tackifier improved the cohesive strength of the adhesive. Adhesion strength is affected by two factors: the development of interfacial adhesion and cohesive strength. In the MAM/MA/tackifier system, the presence of MA and the tackifier improved the interfacial adhesion and cohesive strength, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

反应条件对共沉淀法制备纳米钛酸钡粉体的影响

以钛酸四丁酯、草酸、草酸钠和醋酸钡为原料,采用共沉淀法制备了纳米钛酸钡粉体。通过XRD、IR和TG等检测手段,研究pH值和煅烧温度对粉体纯度的影响。结果表明,制备的前驱体为钛钡混合草酸盐沉淀。pH在3~6的范围内,随着pH值的提高,粉体的纯度下降,粒径减小。随着煅烧温度的升高,粉体的纯度提高。煅烧温度太高,钛酸钡易从立方相转变为四方相。最佳实验条件为pH=3.14,煅烧温度900℃。在此实验条件下,成功制备出均匀的粒径尺寸为37.2nm的纯相纳米钛酸钡粉体。     

Influence of filtration conditions evaluated by X-ray computerized tomography

This research article investigates the effect of flow rate conditions on particle distribution within cartridge filters using X-Ray computerized tomography. Graphical analysis and an image reconstruction technique show that particle distribution and particle capture efficiency are significantly different for each flow condition.     

Influence of operating conditions on particulate fouling

The influence of flow velocity and particle size on the deposition of suspended alumina particles onto heat transfer surfaces was measured with two fouling probes, namely, a heated cylindrical rod in an annulus and a coiled wire in crossflow. Additionally, the response of the fouled probes to such changes as may occur in operating heat exchangers was investigated. The measured influence of flow velocity, wall temperature, bulk temperature, heat flux, particle concentration and particle size on the fouling behaviour as described in this paper and in a companion paper is compared to the predictions of several fouling models from the literature, and recommendations are made for further improvement of these models.