Influence of rubber composition on migration behaviors of antiozonants in carbon black‐filled rubber vulcanizates composed of NR,SBR, and BR

Migration behaviors of antiozonants in carbon black‐filled rubber vulcanizates with different rubber compositions of natural rubber (NR), styrene–butadiene rubber (SBR), and butadiene rubber (BR) were studied at constant temperatures of 40–100°C and outdoors. Three single rubber‐based vulcanizates, three biblends, and three triblends were used. N‐Phenyl‐N′‐isopropyl‐p‐phenylenediamine (IPPD) and N‐phenyl‐N′‐(1,3‐dimethylbutyl)‐p‐phenylenediamine (HPPD) were employed as antiozonants. Migration rates of the antiozonants became faster with increasing the temperature. The order of the migration rates in the single rubber‐based vulcanizates was BR > NR > SBR. The migration rates in the vulcanizates containing SBR, on the whole, increased with decreasing the SBR content, while those in the vulcanizates containing BR decreased with decreasing the BR content. Difference in the migration behaviors of the antiozonants depending on the rubber composition was explained both by the intermolecular interactions of the antiozonants with the matrix and by interface formed between dissimilar rubbers in the blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 237–242, 2001     

Migration behaviors of antiozonants to the surface in NR vulcanizates,depending on the season: The effect of wax

Influence of wax film on the surface of a rubber vulcanizate on migration of antiozonants was studied using NR vulcanizates containing various types of waxes. The waxes have different molecular weight distributions. N‐phenyl‐N′‐isopropyl‐p‐phenylenediamine (IPPD), N‐phenyl‐N′‐(1,3‐dimethylbutyl)‐p‐phenylenediamine (HPPD), N,N′‐di(sec‐butyl)‐p‐phenylenediamine (SBPPD), and N,N′‐di(1,4‐dimethylpentyl)‐p‐phenylenediamine (DMPPD) were used as antiozonants. Migration experiments were performed outdoors for two months in the summer, fall, and winter. The migration rates of the antiozonants in the vulcanizate without wax are faster than those in the vulcanizates with waxes. The antiozonants migrate slower in the vulcanizate containing wax with a high‐molecular‐weight distribution than in the vulcanizate with a low one. In the summer, the migration rates of SBPPD and DMPPD are faster than those of IPPD and HPPD, respectively. But, in the fall, the migration rates of SBPPD and DMPPD are slower than those of IPPD and HPPD, respectively. The differences of migration behaviors of the antiozonants, depending on season and wax type, was discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1987–1993, 1999     

宾馆内空气中甲醛与温度的关系分析

按季度对室内甲醛进行监测,同步记录采样点温度。监测数据按季度进行统计分析,发现宾馆内甲醛释放浓度受温度影响显著(r=0.829),且二者年变化规律呈倒"V"型,峰值出现在第3季度;在一定的时间区间内,甲醛合格率年变化趋势呈正"V"型,第3季度甲醛合格率达到全年最低点,其与采样点温度之间呈极显著负相关(r=-0.941)。甲醛的释放具有很强的季节性,其释放周期应按年进行统计。     

Correlation of bitumen viscosity with temperature and pressure

A previous viscosity-temperature correlation (Puttagunta et al., 1992) is extended to include a pressure term and employed successfully in predicting the combined effect of temperature and pressure on the viscosity of Canadian bitumens and heavy oils. Predictions are made on new sets of data based on a single measurement of viscosity at 30°C and 101.3 kPa pressure; and the results show similar accuracy as obtained in the sets of data used in developing the correlation. The correlation yields an absolute average deviation between predicted and experimental viscosity of 4.79% and a correlation coefficient of 0.99 over a range of temperatures between 20 and 120°C and gauge pressures between 0 and 18 MPa.     

Testing Non‐Correlation and Non‐Causality between Multivariate ARMA Time Series

Abstract. Haugh [Journal of the American Statistical Association (1976) Vol. 71, pp. 378–85] developed an approach to the problem of testing non‐correlation (at all leads and lags) between two univariate time series. Haugh's tests however have low power against two series which are related over a long distributed lag when individual lag coefficients are relatively small. As a remedy, Koch and Yang [Journal of the American Statistical Association (1986) Vol. 8, pp. 533–44] proposed an alternative method that performs better than Haugh's under such dependencies. A multivariate extension of Haugh's procedure was proposed by El Himdi and Roy [The Canadian Journal of Statistics (1997) Vol. 25, pp. 233–56], but suffers the same weaknesses as the original univariate method. We develop here an asymptotic test generalizing Koch and Yang's method to the multivariate case. Our method includes El Himdi and Roy's as a special case. Based on the same idea, we also suggest a generalization of the El Himdi and Roy procedure for testing causality in the sense of Granger [Econometrica (1969) Vol. 37, pp. 424–38] between two multivariate series. A Monte Carlo study is conducted, which indicates that our approach performs better than El Himdi and Roy's for a wide range of models. Both procedures are applied to the problem of testing the absence of correlation between Canadian and US economic indicators, and to a brief study of causality between money and income in Canada.     

化合物的结构与颜色

颜色是物质的重要物理性质,化合物显色与很多因素有关。主要从外界温度、物质聚集状态、电子跃迁、离子极化等多个角度对化合物颜色变化的因素进行阐述和分析。     

蓄顶温度与火道温度关系模型辨识新方法

针对焦炉火道温度与蓄顶温度关系模型的辨识问题,提出了一种基于区间预估最小二乘法的模型辨识方法.此方法可以有效消除煤气交换给火道温度和蓄顶温度带来的趋势不同的影响.使用置信区间的预计算,能够避免辨识数据紧凑带来的拟合数据准确而物理意义不准确的问题.     

大气污染物与降水中酸性离子相关性研究

对二氧化硫(SO2)、二氧化氮(NO2)以及降水中的典型酸性离子浓度进行连续监测,分析了大气SO2、NO2与降雨中SO2-4、NO-3离子之间的相关性。石嘴山市五年期间SO2排放量略有降低,NO2排放量逐年增加。大气中SO2及NO2分别在2009年及2010年达到最大值,为0.08 mg·m-3及0.04 mg·m-3;SO2-4/NO-3比例逐年下降,由2007年的19.74降低至2012年的3.28;石嘴山市近年来降水类型的转变一方面原因是在SO2减排背景下的NO2大幅增加,另一方面是大气中氧化水平的不断升高,使NO2氧化率大幅增加。     

污水紫外吸光度与COD相关性的研究

紫外分光光度法测定水质COD是利用有机物吸收紫外线的特征来测量水中的有机物浓度。与传统COD监测方法相比,它是一种不用化学试剂、对样品无须加热消解、快速、简洁、无二次污染的绿色监测技术。本文通过研究生活污水和工业废水样品的紫外吸光度与化学需氧量之间的相关性,得出在水质稳定的条件下,可利用测定的紫外吸光度值推算出化学需氧量的结果。     

胆汁酸溶解度的测定与数据关联

在胆汁酸结晶过程中,温度对胆汁酸在不同有机溶剂中溶解度的影响至关重要。采用平衡法结合HPLC法测定303.15~353.15 K胆酸、鹅去氧胆酸、熊去氧胆酸在5种有机溶剂中的溶解度,分别采用多项式经验方程和理想溶液方程对实验数据进行关联。结果表明,胆酸、鹅去氧胆酸、熊去氧胆酸在不同有机溶剂中的溶解度均随温度升高而增加,这两种方程均能较好地关联溶解度实验数据,其中多项式经验方程关联的相关系数均在0.98以上。     

关于COD_(Mn)两种方法的相关性研究

长江入海口受咸淡水影响,盐度变化较大。分别通过高锰酸盐指数法和碱式高锰酸钾法对长江口不同盐度水样的CODMn进行测定,并对两种方法进行比对校正。结果表明,两组数据具有明显的正相关关系;经实际数据检验以及测量值和拟合值之间的统计检验分析得出:两组数据之间没有显著差异,两种方法显著相关。为长江口水体CODMn的监测提供了数据支撑,以解决海上和陆地COD监测之间的数据衔接问题。     

Gelation behaviors of cellulose solution dissolved in aqueous NaOH/thiourea at low temperature

Cellulose was dissolved rapidly in 9.5 wt% NaOH/4.5 wt% thiourea aqueous solution pre-cooled to −5 °C, as a result of the formation of an inclusion complex (IC) associated with cellulose, NaOH and thiourea, which could bring cellulose to the aqueous system. To clarify the rheological behaviors of the system dissolved at low temperature, this cellulose solution was investigated by dynamic viscoelastic measurement. The shear storage modulus (G′) and loss modulus (G″) as a function of the angular frequency (ω), concentration (c), temperature (T) and weight-average molecular weight (M_w) were analyzed and discussed. The results revealed that gels could form in the cellulose solution at either high temperature or low temperature, or for longer time. Interestingly, 4 wt% cellulose solution having cellulose M_w of 12.0 × 10⁴ remained at liquid state for longer time (12 days) at the temperature ranging from 0 to 5 °C. The gels already formed at elevated temperature were irreversible, i.e., after cooling to lower temperature including the temperature of cellulose dissolution (−5 °C), they could not be dissolved to become liquid. The Arrhenius analysis of the temperature dependence of viscosity in the cellulose solution indicated that a high apparent activation energy (E_a) occurred at 0 to −5 °C, suggesting the relatively stable IC structure. However, the viscosity of the cellulose solution increased slowly with an increase in the temperature at 0-40 °C, leading to the negative E_a values. The results suggested that the cellulose solution in NaOH/thiourea system is complex to differ from normal polymer systems.     

AF反应器运行参数的相关性研究

针对PTA废水特性,主要研究了AF反应器在稳定运行中一些参数的变化对处理效果的影响.根据这些参数之间的关系确立了AF反应器出水COD浓度与进水COD之间的关系,并根据连续性的数据归纳提出了其间的相关性方程,这有利于进一步研究PTA废水在污水处理装置上COD的去除关系,消除生化处理的人为因素,从而提高废水生化处理效果.     

煤焦油中含水量与密度之间的关联研究

以中煤九鑫焦化有限公司煤焦油为样品,探讨了不同温度下煤焦油水分与其密度之间的关联关系。结果表明,在不同温度下,含水质量分数4%焦油的密度随温度升高而不断降低;同一温度下,焦油密度随含水量升高而降低。实际生产中,可利用密度推算出一定温度下的焦油含水量,从而及时调整小氨水澄清槽焦油水分离以及焦油产品储槽自动控制水分脱除程度(≤4%),以减少脱水消耗蒸汽量。     

50%噻苯隆WP在棉叶、棉籽和土壤中的残留分析及消解动态

建立了用高效液相色谱法检测棉叶、棉籽和土壤中噻苯隆残留量的分析方法。棉叶、棉籽和土壤样品经乙腈或丙酮/水提取,用装有无水硫酸钠和碱性氧化铝的层析柱净化,以C18柱作为分析柱,乙腈与水混合液(体积比为40:60)作为流动相,在288nm的检测波长下,用高效液相色谱法定量测定棉叶、棉籽和土壤中残留噻苯隆。在噻苯隆添加质量为0.01mg/kg、0.1mg/kg和0.5mg/kg时,土壤样品中噻苯隆残留分析测定的平均回收率为85.70%、91.10%和94.65%,变异系数为5.58%、2.37%和2.70%;棉叶样品中噻苯隆残留分析测定的平均回收率为84.20%、88.73%和90.07%,变异系数为4.86%、3.98%和3.59%。棉籽样品中噻苯隆残留分析测定的平均回收率为85.29%、86.69%和89.96%,变异系数为4.60%、4.10%和4.84%。应用上述方法测定湖南长沙和浙江杭州两地棉叶和土壤中的降解动态,结果表明,噻苯隆在棉叶及其土壤中的消解动态符合一级动力学方程,长沙棉叶和土壤中的半衰期分别为3.08d和9.71d;杭州棉叶和土壤中的半衰期分别为1.89d和7.07d。     

干湿循环和暴露对混凝土氯离子结合能力相关性研究

进行了盐湖现场暴露和干湿循环环境下钢筋混凝土梁腐蚀试验,分别测定了不同试验环境下钢筋混凝土梁在不同深度的总氯离子浓度和自由氯离子浓度,运用回归分析干湿循环和盐湖现场暴露环境下混凝土氯离子结合能力的相关性系数K与扩散深度、混凝土抗强度的关系。结果表明：随着氯离子扩散深度和混凝土的抗压强度的增加,氯离子结合能力相关性系数K呈指数函数形式递减,研究成果可用于利用干湿循环测定的氯离子结合能力来预测实体结构不同深度内的氯离子结合能力。     

耐高温隔热涂料的隔热性与涂层厚度相关性探讨

探讨了耐高温隔热涂料的隔热性与涂层厚度的相关性,利用相关性指导选择适宜的涂层厚度,达到保温隔热的目的。     

Correlation between the ash composition and melting temperature of waste incineration residue

The correlation between the ash composition of various incinerated waste residues and their melting temperatures was examined by using their chemical composition parameters. There was a low correlation between the melting temperatures and the acidic oxide content in the ashes. However, the composition parameters derived from the basic oxides showed a good correlation with the ash melting temperature. The composition parameter, P₇, which is defined as the ratio of basic oxides (CaO+MgO+K₂O+Na₂O) to acidic oxides (SiO₂+Al₂O₃+Fe₂O₃), showed a strong correlation with the ash melting temperature. By fitting the composition parameter to the experimental data, the correlation equation for the half fluid temperature (HFT) was found to be HFT=426.77P ₇ ² ?736.76P₇+1592.3 with a correlation coefficient of 0.91. The correlation equation could be used to predict the melting temperatures of various waste incineration residues. The relative error between the measured and predicted melting temperature was approximately 5%. Overall, these parameters and correlation equations can be used to predict and reduce the melting temperature of incineration residues.     

凹凸棒土高温改性的研究

为提高凹凸棒土的吸附性能,通过高温对其进行改性,将其应用于吸附含铬废水。结果表明,高温改性可以脱去凹凸棒土中的吸附水、沸石水和部分结晶水,比表面积随改性温度的提高先增大后减小,当温度为350℃时,可以获得最大的比表面积140.7 m2/g,其Cr6+去除率可以达到80%。     

Wetting,reactivity, and phase formation at interfaces between Ni–Al melts and TiB2 ultrahigh‐temperature ceramic

The wetting, reactivity, and phase formation at the liquid Ni–Al/TiB₂ ceramic interfaces have been investigated at the temperatures close to the Ni–Al liquidus line. The wetting kinetics has been studied by the sessile drop technique utilizing liquid drop dispension and high‐speed high‐resolution video imaging. It is established that the wetting behavior changes from a nonreactive for the Al‐rich melts to a dissolution‐reactive for the Ni‐rich melts. For the Ni concentration ≥40 at.%, TiB₂ precipitates are found in the solidified Ni–Al droplets after the high‐temperature interaction of the melts with TiB₂ substrates. Besides, new (Al,Ti)Ni₃ and (Al,Ti)₂Ni₂₁B₆ phases are formed due to dissolution of TiB₂ ceramic in Ni‐rich melts and subsequent solidification.