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《化工新型材料》2016,(1)
以芋头秸秆——芋叶柄为原料,采用预水解硫酸盐蒸煮法制备芋叶柄纤维浆粕。通过二煮二漂工艺,考察酸预水解、蒸煮及漂白的最佳工艺条件,对芋叶柄纤维浆粕进行α-纤维素含量测试、聚合度测试、白度测试、扫描电子显微镜(SEM)表征,结果表明:酸预水解最佳工艺条件为保温时间4h、温度130℃、酸用量4%(wt,质量百分数,下同)。蒸煮最佳工艺条件为碱用量35%、硫化度40%、蒽醌用量0.1%、保温时间4h。漂白工艺为一漂双氧水,二漂次氯酸钠。芋叶柄纤维浆粕表面纤维呈带状,不仅分离成单根状态,且纤维表面已经呈现出原纤化,有收缩起皱的现象,沟槽较多。芋叶柄纤维浆粕测试结果中α-纤维素的含量达到90.56%,白度68.8%,聚合度621.84。 相似文献
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用NaOH溶液对废纸纤维进行预处理,制备了一种纸纤维发泡缓冲包装材料,研究了NaOH预处理对废纸纤维发泡材料性能的影响。结果表明:经NaOH溶液预处理后,纸纤维发泡材料的发泡倍率、密度及缓冲性能均较未处理试样有所改善;NaOH的用量对纸纤维发泡材料性能的影响,较处理温度和处理时间的影响更为显著。同时,通过试验确定了最佳的废纸纤维发泡缓冲材料预处理条件,即NaOH添加质量为相对于绝干废纸浆质量的2%,且在60℃恒温条件下处理60min。 相似文献
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棉秆皮纤维的提取及其结构、性能研究 总被引:1,自引:0,他引:1
为更有效地利用废弃农作物秸秆资源,研究了常温常压碱处理提取天然棉秆皮纤维的技术,讨论了氢氧化钠溶液质量浓度、温度和时间等碱提取工艺参数对棉秆皮失重率的影响,并采用FT-IR、SEM、XRD等方法对优化工艺提取的棉秆皮纤维的化学成分、表面形态、结晶结构、力学性能等进行了表征。结果表明,NaOH质量浓度为15g/L、液固比为30mL/g、处理温度为100℃、处理时间为120min时,棉秆皮失重率较大,木质素、半纤维素、果胶等杂质去除较多。天然棉秆皮纤维结晶度为53.72%,断裂强度约1.6cN.dtex-1,断裂伸长率为5.91%,性能接近天然纤维素纤维黄麻。 相似文献
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《化工新型材料》2016,(9)
以芋头秸秆-芋叶柄为原料,对芋叶柄的化学成分进行测试分析,采用一煮法制备芋叶柄纤维,考察碱煮的最佳工艺条件。对芋叶柄纤维进行回潮率测试和扫描电子显微镜(SEM)表征测试。结果表明,芋叶柄主要化学成分为35.01%(wt,质量分数,下同)水溶物、30.30%纤维素、14.53%半纤维素、8.83%木质素,这4种组分组成了芋叶柄主体。碱煮最佳工艺条件为NaOH用量10%、保温时间240min、平平加O用量4g/L。芋叶柄纤维的回潮率为5.81%,表面有明显的竖纹和沟槽,外观粗糙,不光滑;截面形状不规则且实体无空腔,纤维粗细不均匀,并且有短纤维粘连在一起,属于工艺纤维。 相似文献
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为了改善8YSZ陶瓷的力学性能,以8YSZ双粒度粉体为研究对象,对其进行干压成型、无压烧结实验。对成型压力、保压时间及黏结剂用量等成型工艺参数进行了优化;利用正交实验对烧结方案进行了设计,讨论了烧结温度、升温速率、保温时间、烧结方式等烧结工艺参数对8YSZ陶瓷烧结性能和力学性能的影响,并优化出其烧结工艺参数。结果表明:选取PVA加入量10%(质量分数)、成型压力10MPa、保压时间30s的成型工艺参数,可压制出相对密度为54.9%的陶瓷坯体;选取烧结温度1500℃,保温时间4h,升温速率5℃/min,烧结方式裸烧的烧结工艺参数,可制备出相对密度为98.3%,抗弯强度为100.3MPa的8YSZ陶瓷。 相似文献
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目的 探讨热压过程中压力、温度和湿纸胚含水率等因素对稻草秸秆纤维模塑包装材料主要力学性能的影响,确定各因素的权重及最佳工艺参数。方法 采用单因素试验法和响应曲面法,以裂断长和弯曲强度为评价指标,确定最佳工艺条件。结果 最佳热压工艺条件,热压温度为175 ℃,热压压力为6.9 MPa,湿纸胚含水率为70%,此时得到的平均裂断长为7697.93 m,弯曲强度为72.36 MPa,与理论裂断长7712.62 m、弯曲强度71.44 MPa接近,优化结果可信。热压过程中各因素对模塑包装材料裂断长和弯曲强度影响的大小为湿纸胚含水率>热压压力>热压温度。结论 过高的温度会造成半纤维素的热解,过高的压力会导致纤维的压溃,过高的含水率产生的能耗过高。适当的热压工艺参数能够降低能耗,保证模塑包装材料的品质及性能。 相似文献
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Masao Doyama 《Bulletin of Materials Science》1999,22(3):723-728
By making a step on one surface (
) of a rectangular small paralellepiped copper crystal, dislocations could be created by the molecular dynamic method. The
dislocation created was not a complete edge dislocation but a pair of Heidenreich-Shockley partial dislocations. Each time
a dislocation was created, the stress on the surface was released. Small copper crystals having a notch were pulled (until
fracture), compressed and buckled by use of the molecular dynamic method. An embedded atom potential was used to represent
the interaction between atoms. Dislocations were created near the tip of the notch. A very sharp yield stress was observed.
The results of high speed deformations of pure silicon small crystals using the molecular dynamics are presented. The results
suggest that plastic deformation may be possible for the silicon with a high speed deformation even at room temperature. Another
small size single crystal, the same size and the same surfaces, was compressed using molecular dynamic method. The surfaces
are {110}, {112} and {111}. The compressed direction was [111]. It was found that silicon crystals are possible to be compressed
with a high speed deformation. This may suggest that silicon may be plastically deformed with high speed deformation. 相似文献
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目的 探索江门世遗文化的传承、发展和转化的新思路,践行国家在《粤港澳大湾区发展规划》纲要中要求江门承担与港澳地区文化创意合作与开发任务的分工。方法 与澳门高校紧密合作,开展专业培训课程,以开平碉楼为例,从人文视角开展设计研究,梳理开平碉楼的文化脉络,把世遗文化的元素和其背后的文化融入文创产品中,提升文创产品的附加值,推动当地文创产业结构的变革。结果 两地高校构建了稳定的科研团队,开设长期有效的设计培训课程,与景区建立了研究协作关系,帮助景区构建了一套产销研的商业模式。结论 以跨区域高校合作为平台,以文创产品为抓手,依托江澳两地的资源优势,可以构建江门世遗文化全新的品牌形象,最终推动开平世遗文化的活化。 相似文献
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Albert C. Parr 《Journal of research of the National Institute of Standards and Technology》2001,106(1):151-186
The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements. 相似文献
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Production planning and scheduling are becoming the core of production management, which support the decision of a petrochemical company. The optimization of production planning and scheduling is attempted by every refinery because it gains additional profit and stabilizes the daily production. The optimization problem considered in industry and academic research is of different levels of realism and complexity, thus increasing the gap. Operation research with mathematical programming is a conventional approach used to address the planning and scheduling problem. Additionally, modeling the processes, objectives, and constraints and developing the optimization algorithms are significant for industry and research. This paper introduces the perspective of production planning and scheduling from the development viewpoint. 相似文献
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Adenosine triphosphate (ATP) is a central metabolite that plays an indispensable role in various cellular processes, from energy supply to cell-to-cell signaling. Nature has developed sophisticated strategies to use the energy stored in ATP for many metabolic and non-equilibrium processes, and to sense and bind ATP for biological signaling. The variations in the ATP concentrations from one organelle to another, from extracellular to intracellular environments, and from normal cells to cancer cells are one motivation for designing ATP-triggered and ATP-fueled systems and materials, because they show great potential for applications in biological systems by using ATP as a trigger or chemical fuel. Over the last decade, ATP has been emerging as an attractive co-assembling component for man-made stimuli-responsive as well as for fuel-driven active systems and materials. Herein, current advances and emerging concepts for ATP-triggered and ATP-fueled self-assemblies and materials are discussed, shedding light on applications and highlighting future developments. By bringing together concepts of different domains, that is from supramolecular chemistry to DNA nanoscience, from equilibrium to non-equilibrium self-assembly, and from fundamental sciences to applications, the aim is to cross-fertilize current approaches with the ultimate aim to bring synthetic ATP-dependent systems closer to living systems. 相似文献