基于边界跟踪测量麻纤维横截面参数的算法研究与应用

针对在同一纤维横截面图像中难以同时测量多根纤维参数的问题,提出了一种基于边界跟踪测量麻纤维横截面参数的算法。首先利用边缘提取算法提取麻纤维的边缘,通过修改边缘提取算法的敏感度阈值获取合适的边缘检测图像,然后采用边界跟踪算法对边缘检测图像中的麻纤维进行识别和标记,利用循环标记出图像中所有的麻纤维并保存边界跟踪的路径点坐标,最后利用算法测量麻纤维的周长、面积和圆度。实验结果表明:该方法能够同时测量多根麻纤维的横截面参数;根据用于测试的标准圆的数据可知,本算法测得的麻纤维的周长偏差大约为3%,面积偏差大约为4%,数据误差较小。     

灌溉周期对工业大麻秆部分理化性能的影响Ⅱ.灌溉周期对纤维素相对结晶度和晶胞尺寸的影响

为更好利用生物质材料,研究纤维素的相对结晶度和晶胞尺寸及其影响因素,用广角X射线衍射仪,研究了不同灌溉周期（3天浇一次水、14天浇一次水、不浇水）对工业大麻秆纤维素相对结晶度和晶胞尺寸的影响。结果表明在整个生长期中,随着生长期延长纤维素的相对结晶度呈增加趋势,晶胞尺寸呈减小趋势;不同灌溉周期对纤维素相对结晶度和晶胞尺寸影响显著（P≤0.05）;纤维素的物理结构在纤维细胞壁不同层次中是不同的。     

Influence of alkali fiber treatment and fiber processing on the mechanical properties of hemp/epoxy composites

Industrial hemp fibers were treated with a 5 wt % NaOH, 2 wt % Na₂SO₃ solution at 120°C for 60 min to remove noncellulosic fiber components. Analysis of fibers by lignin analysis, scanning electron microscopy (SEM), zeta potential, Fourier transform infrared (FTIR) spectroscopy, wide angle X‐ray diffraction (WAXRD) and differential thermal/thermogravimetric analysis (DTA/TGA), supported that alkali treatment had (i) removed lignin, (ii) separated fibers from their fiber bundles, (iii) exposed cellulose hydroxyl groups, (iv) made the fiber surface cleaner, and (v) enhanced thermal stability of the fibers by increasing cellulose crystallinity through better packing of cellulose chains. Untreated and alkali treated short (random and aligned) and long (aligned) hemp fiber/epoxy composites were produced with fiber contents between 40 and 65 wt %. Although alkali treatment generally improved composite strength, better strength at high fiber contents for long fiber composites was achieved with untreated fiber, which appeared to be due to less fiber/fiber contact between alkali treated fibers. Composites with 65 wt % untreated, long aligned fiber were the strongest with a tensile strength (TS) of 165 MPa, Young's modulus (YM) of 17 GPa, flexural strength of 180 MPa, flexural modulus of 9 GPa, impact energy (IE) of 14.5 kJ/m², and fracture toughness (K_Ic) of 5 MPa m^1/2. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

KOH活化法制备汉麻秆活性炭及其微孔结构的研究

采用生物质材料制备比表面积大、微孔结构发达的活性炭,对于缓解资源紧缺、拓展活性炭在气相吸附和双电层电容器等方面的应用具有重大意义。以汉麻秆为原料、KOH为活化剂制备活性炭,通过正交试验探讨碱炭比、活化温度、活化时间对活性炭得率和碘吸附值的影响;采用场电镜、孔径分析仪对样品的微孔结构进行分析。结果表明,影响活性炭得率和碘吸附值的最显著因素分别为碱炭比和活化温度,在碱炭比4∶1、活化温度900℃、活化时间为0.5h的条件下,活性炭得率为72%、碘吸附值为2 047mg/g,比表面积为1 924.08m2/g,总孔容为1.01cm3/g,平均孔径为2.1nm;该活性炭的微孔结构发达(微孔率为81.19%),孔径分布较窄,同时存在超微孔和极微孔,且极微孔含量很高。     

Effects of the addition of hemp powder on the physicochemical properties and energy bar qualities of extruded rice

Extruded rice/hemp mixtures were prepared by mixing defatted and whole hemp powders with rice flour at varying hemp levels (0%, 20%, 30% and 40%). The influence of hemp powder type and level on physicochemical and antioxidant properties was studied. The bulk densities of the extruded rice/hemp samples increased with increase in levels of added hemp powder. The extrudates blended with hemp powder had a lower water absorption index than the control (extruded rice without hemp). The extruded rice/whole hemp had more total phenolics and flavonoids and had a better scavenging effect on DPPH radicals than extruded rice/defatted hemp. The highest potential to inhibit β-carotene oxidation was found in extruded rice/40% whole hemp. Increasing amounts of hemp powder resulted in lower equilibrium moisture content of energy bars. The energy bar made with extruded rice/20% whole hemp was preferred for colour, taste and overall acceptability.     

拔杆注射模设计

通过对拔杆的工艺分析，介绍了该拔杆注射模的整体结构及设计要点，研究了模具侧抽、成型、顶出等过程，分析了型腔分布的结构特点，提出了一种较为独特的的模具结构，实现了拔杆的顺利成型，解决了侧向斜孔成型困难等问题。     

Evaluation of the Influence of Fibre Length and Concentration on Mechanical Performance of Hemp Fibre Reinforced Polypropylene Composite

Abstract

The paper deals widi die evaluation of interfacial shear stress (ISS) between reinforcement fibre (hemp) and polypropylene matrix through single fibre pull-out method and subsequently the critical length of the composite grade hemp fibre has been determined. In the present study the average ISS value of 5.9 MPa was used to determine the critical length of hemp fibre, which was found to be 3.4 mm. The theoretical prediction of the tensilestrength and modulus of hemp-polypropylene composite by using Kelly-Tyson and Cox-Krenchel models, respectively, have been reported in the paper. Model results were validated by experimental works with different fibre lengths and volume fraction of hemp fibre in the composite. The effect of fibre length and content on the flexural strength and stiffness of the hemp-polypropylene composite has also been studied. The effect of moisture absorption on composite tensile strength was predicted by modifying the Kelly-Tyson model. The model curve was also compared with another set of experimental works done at differentmoisture contents in the composite.     

Trends and Methods in Hemp Breeding in Poland

Abstract

The growth of hemp cultivation area in the world is a result of increasing its multidirectional utilization. This causes an urgent need of creating varieties adapted to requirements of new trends in hemp utilization by interested industries.

To accomplish these goals traditional and biotechnological methods of breeding are being modified. However, due to high costs of employing highly qualified personnel and acquiring materials for breeding, the process of obtaining results could be accelerated by more effective international cooperation. The trends, objectives and methods of breeding realized in Poland are targeted at bringing breeding centers near to cooperation.     

大麻/彩棉交织物蓬松柔软整理

为了提高大麻/彩棉交织物的柔软度,分别选用弱阳离子型柔软剂和阳离子型蓬松片对织物进行处理,以抗弯刚度为主要评价指标。考虑到柔软剂与蓬松片的交互作用,通过二次回归正交试验建立回归方程,确定交互作用下试剂的最佳浓度。通过对处理前后交织物的断裂强力、断裂伸长及手感进行对比分析最后得出最佳整理工艺:柔软剂的质量浓度为7.656 g/L,蓬松片的质量分数为6.862%。经蓬松柔软处理的大麻/彩棉交织物,硬挺度明显下降,手感丰满、滑糯,柔软度明显增加且强力损失较小。