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针对对位芳纶纸强度低的特性,本试验着重研究了一种新型热塑性黏结纤维Y对芳纶1414纸基复合材料物理强度、介电性能及纸张表面的影响,通过设计正交实验,探讨了热压工艺对复合对位芳纶纸的增强效果。结果表明,在黏结纤维Y用量为10%时(对总的绝干纤维量),芳纶1414纸基复合材料可以达到较为理想的增强效果,在此条件下制得的对位芳纶纸主要强度指标分别为抗张指数77.03N.m/g,撕裂指数24.10mN.m2/g,伸长率1.75%,耐电压强度16.33kV/mm,300℃下纸张热失重为9.01%。另一方面,复合对位芳纶纸的正交热压实验表明,对于成纸的机械强度和介电性能,预热温度为最主要影响因素,热压压力和压辊转速次之,热压次数影响相对较小;复合对位芳纶纸最佳热压工艺条件为:预热温度180℃,热压压力14MPa,热压次数1次,辊子转速1r/min。 相似文献
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实验中将芳纶短切纤维和沉析纤维(浆粕)按照一定比例混抄、热压,系统地研究了热压对间位芳纶纸的纤维形态、物理结构、表面性能及某些物理性能的影响。结果表明:热压对纸张的性能影响很大,热压后纸张的表面变得平整光滑,略为半透明状,内部结构更加紧密。同时,芳纶纸的紧度、抗张强度和伸长率随热压温度的升高而增大,与未压纸相比,热压温度达到130℃时,纸张紧度达到3.92倍,抗张强度和伸长率也分别提高了4.65倍和7.23倍,继续提高热压温度,各性能指标的增长速率都趋于缓和。撕裂强度则是随热压温度的升高先增大后减小,热压温度达到130℃时,撕裂强度提高2.54倍,然后随温度的升高而降低,并最终趋于稳定值。 相似文献
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通过正交实验探讨了分散浓度、超声时间、超声功率及分散剂用量对纳米SiO2分散性能的影响,并将纳米SiO2加入到芳纶纸中,研究了纳米SiO2的添加对纸张强度性能、紧度、介电性能及结晶性能的影响。结果表明,当纳米SiO2的分散浓度为0.1%,超声时间为30 min,超声功率为400 W,分散剂用量为2%时,分散性最好。当纳米SiO2的用量为15%时,芳纶纸具有最大的的抗张指数,为33.51 N·m/g,撕裂指数则在用量为10%时最大,为38.84 mN·m2/g。纳米SiO2的用量为15%时,纸张的耐压强度最大,为13.20 kV/mm,在实验中纳米SiO2的用量范围内,纸张的紧度基本不变。另外,相比未添加纳米SiO2的芳纶纸,加入纳米SiO2后纸张的结晶度有所降低。 相似文献
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大花序桉KP法制浆性能研究 总被引:1,自引:0,他引:1
对我国现有的大花序桉进行纤维形态、化学组成和材质密度的分析,并对其硫酸盐法制浆及抄纸性能进行了研究。大花序桉硫酸盐法蒸煮优化条件为:用碱量19%,硫化度20%,蒽醌用量0.1%,升温时间100~110min,保温时间90~110min,最高蒸煮温度165℃,液比1∶5.5。研究结果表明,大花序桉是较优良的造纸原料。在打浆度为40~50°SR时纸张的各项物理性能比较好,分别为抗张指数39.2~45.2N·m/g,撕裂指数10.5~12.0mN·m2/g,耐折度331~429次,紧度0.428~0.442g/cm3。其撕裂指数优于其他桉木树种。 相似文献
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利用油酸对纳米Mg(OH)2粒子进行改性,使其均匀分散在六甲基二硅醚中,制备成稳定的脱酸液;并将该脱酸液喷涂在老旧纸张上进行纸张脱酸。结果表明,采用0.1 g油酸、1g纳米Mg(OH)_2、100mL六甲基二硅醚,在反应温度50℃、反应时间1h的条件下获得的改性纳米Mg(OH)_2在六甲基二硅醚中具有良好的分散性,可作为脱酸液用于纸张的脱酸。当脱酸液涂布量为2.7 g/m~2时,相对于未脱酸纸,脱酸纸的表面pH值得到了明显提高(从4.00提高到7.92),纸张抗张指数和撕裂指数基本没有变化;经加速老化处理后,脱酸纸表面pH值为7.60左右,抗张指数和撕裂指数稍有下降,但远低于未脱酸纸;加速老化后,脱酸纸的色差为0.64,符合纸张文物"修旧如旧"的原则。 相似文献
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纺织产业集群的经济景气研究在国内处于起步阶段,本文依据产品价格调查方法、企业景气调查方法和企业财务数据构建了专业市场型产业集群经济景气的指标体系,该景气指标体系由产品综合价格指数、市场景气指数和企业现金流指数构成。这一体系在中国东方丝绸市场发布的丝绸化纤指数中得到了运用。 相似文献
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本文从整体和分类两个层面分别计算了植物油籽1999-2008年的G-L产业内贸易指数、Brulhart边际产业内贸易指数、Thom&McDowell边际产业内贸易指数,发现我国植物油籽的整体产业内贸易水平非常低,Brulhart边际产业内贸易指数显示我国植物油籽10年来贸易的增量主要来自于产业间贸易,Thom&McDowell指数表明我国植物油籽产业内贸易主要由水平产业内贸易引发。文章认为应该加快科技兴农步伐,提升我国植物油籽的质量,实施产品差异化战略,促进植物油籽品种的多元化,并争取WTO的特别保障条款,减少进口大豆、油菜籽对我国大豆、油菜产业的冲击。 相似文献
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美国烟叶等级指数的制订与应用 总被引:1,自引:0,他引:1
介绍了美国烟叶等级指数的制订原则、计算方法及其应用 ,并对等级指数与品质指数的概念进行了比较 ,同时提出了建立我国烟叶外观品质评价体系的建议 相似文献
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Isabelle Travers Alain Jacquet Adlaïde Brisset Claire Maite 《Journal of the science of food and agriculture》2002,82(9):983-989
Monitoring the hydrolysis or disappearance of starch by the starch iodine test is a simple procedure for determining the maturity of cider apples, but it does not indicate the exact amount of starch present. So far, studies of starch in apples have dealt exclusively with dessert apples. In this paper the relationship between the visual starch index, the dark‐coloured surface area and the real starch content was studied in two varieties of cider apple commonly used in Normandy (France). Starch determination in cider apples required adapting the protocol provided by the Boehringer enzymatic kit. The work led to proposing a simplified index with five scales instead of 10. This index gives the correspondences between the new and old scales as well as the probable starch contents for each new scale. © 2002 Society of Chemical Industry 相似文献
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A new selection index percent emphasis method using subindex weights and genetic evaluation accuracy
The current international standard methodology to quantify trait percent emphasis in selection indexes is based on a simple multiplication of the relative contribution of each trait's economic value (converted to absolute value) and its genetic standard deviation. This method does not reflect the actual selection emphasis applied when the index is used in practice. The economic value does not reflect selection effort when traits differ considerably in their accuracy of evaluation, and no account is taken for either favorable or antagonistic correlations among traits. A new emphasis method adjusted by both accuracy and genetic correlation is proposed. Genetically highly correlated traits are grouped into subindexes by applying a hierarchical clustering method to the genetic correlation matrix. Then each trait's subindex emphasis is calculated within its subindex group, with a weighting included for trait accuracy. Finally, each subindex emphasis is converted to a full index emphasis according to the conventional relative emphasis of its corresponding subgroup. The method can also be applied to sets of breeding values and their economic weights. When applied to a New Zealand sheep breeding selection index where trait genetic correlations are distinct across subindex groups, the new method shrank the emphasis on low-heritability traits, including survival, from 51% to 19%; and expanded that on growth traits from 30% to 49%, better reflecting the selection pressure applied in reality. When genetic correlations across traits were similar, clustering became difficult. Accounting for accuracy affected traits' within-subindex group rankings, whereas the clustering to account for correlations affected all traits within a subgroup equally. Accounting for differences in trait accuracy when describing percent emphasis within selection indexes gives a more practical indication of the likely outcome of selecting on the index. Accounting for correlations among traits when defining percent emphasis made a significant difference only in a subset of case study examples. 相似文献