对高等院校大学生开展木球运动的探讨

木球是一项新兴的休闲体育运动,它具有男女老少皆宜、简单易学、健身益智、娱乐休闲等特点;根据木球运动的特点与功能,并对高校体育教学现状的分析,提出在高等院校大学生中开展木球运动的可行性,为进一步开展木球运动提供坚实的理论依据。     

东北林蛙蝌蚪试养中饵料的初步研究

从自然环境中获得东北林蛙蝌蚪共638只,在实验室内分装在6个1000ml的大烧杯里,用不同饵料饲养60天,发现饵料不同其生长速度、体重都有所不同,实验发现甲状腺有促进生长发育的作用。     

太阳图纹在彝族服饰上的演变

彝族先民在生产力低下的情况下将太阳形象人格化,并赋予其一种想象的超自然的力量,创作出多种象征太阳的图纹绣在服饰上以祈求保护与庇佑。这种象征原始崇拜的太阳图纹,在服饰上逐步演变,渐渐成为一种极具实用意义的装饰纹样。     

Study of Fe(II) sulphides in waterlogged archaeological wood

Abstract

Wet organic archaeological materials extracted from seawater may suffer damage as a result of degradation influenced by micro-organisms. One of the most common phenomena is indirectly induced by sulphate-reducing bacteria (SRB). Due to their metabolic activity in anoxic conditions, SRB generate hydrogen sulphide from sulphate ions present in seawater. When steel items are in contact with organic matter in presence of sulphides, corrosion of the metal leads to the precipitation of Fe(II) sulphides. These phases are responsible for dramatic post-excavation damage: their oxidation during storage or exhibition in museums leads to the formation of voluminous crystals, which may cause cracking and crumbling, and lead to the production of sulphuric acid. In order to characterize Fe(II) sulphides and their by-products, 13 waterlogged samples were analysed by environmental scanning electron microscopy, micro-Raman spectroscopy, and X-ray diffraction. Experiments were performed on untreated wood fragments, on a fragment of rope, and on mineral concretions scratched from the surface of wood remains, all extracted from different shipwrecks. Mackinawite was detected inside the fragments and between the fibres of the rope. Greigite was detected in scattered locations. Pyrite and sulphated phases, like gypsum and iron sulphates, were identified at the surface of the wood fragments and in the mineral concretions.     

Regenerated isotropic wood

Construction of sustainable high-performance structural materials is a core part of the key global sustainability goal. Many efforts have been made in this field; however, challenges remain in terms of lowering costs by using all-green basic building blocks and improving mechanical properties to meet the demand of practical applications. Here, we report a robust and efficient bottom-up strategy with micro/nanoscale structure design to regenerate an isotropic wood from natural wood particles as a high-performance sustainable structural material. Regenerated isotropic wood (RGI-wood) exceeds the limitations of the anisotropic and inconsistent mechanical properties of natural wood, having isotropic flexural strength of ∼170 MPa and flexural modulus of ∼10 GPa. RGI-wood also shows superior water resistance and fire retardancy properties to natural pine wood. Mass production of large sized RGI-wood and functional RGI-wood nanocomposites can also be achieved.     

42种阔叶树材木纤维长度和宽度的研究

对42种阔叶树材木纤维的长度和宽度进行了测定。结果表明,纤维最短的是芒果(842μm),最长的为木棉(2258μm);宽度最小的是相思树(15μm),最大是拟赤杨(44μm);纤维长宽比值,最低是泡桐仅为31,最高是木棉83。天然野生的酸枣和杜英与人工栽培的对比,二者的纤维长度均存在极显著差异,酸枣纤维宽度差异不显著,杜英差异显著。盆架木的纤维长度和宽度,集美产的和龙岩产的对比均存在显著差异,银桦和芒果纤维长度和宽度不同产地之间均无显著差异。     

The wood of “C” and “F” Roman ships found in the ancient harbour of Pisa (Tuscany, Italy): the utilisation of different timbers and the probable geographical area which supplied them

During the excavation of the Etruscan and Roman harbour of Pisa, several shipwrecks were found. The wooden timbers constituting the ship C and ship F (which date back to the first and the second century A.D., respectively, as attested by archaeological findings) were selected in order to collect information about the technological knowledge of the time. Pinus pinaster Aiton was essentially utilised for the planking of ship C and Quercus sp. caducifolia for that of ship F. The choice of timber for the other parts of ship C hull was much more differentiated. Ship C seems to be built in a careful way and its characteristics when added to its overall lightness, seem to reflect its use as a higher capacity boat built for sea sailing. Ship F seems more linked to short voyages in inner fresh waters. The utilisation of different woods was linked not only to the technological characteristics of wood, but also to their easy availability. Palynological analysis, carried out on the clay sediments embedding the shipwrecks, has shown that the flora of Pisa area in that time period would have allowed the acquisition of all the timber species used for both the ships’ construction, with the exception of the fig wood. However, a foreign origin of the timber from somewhere else in the Northern Mediterranean area has not been excluded.     

木材干燥过程中一个非线性模型的二阶收敛差分格式

针对描述木材干燥过程中的一个非线性微分方程模型,用降阶法对其建立了一个差分格式.此模型是由一个非线性常微分方程和一个非线性抛物方程组成的耦合微分方程组.首先引进一个新变量把原问题转化为一阶微分方程组问题,然后对此一阶微分方程组建立了一个线性化差分格式,应用能量方法证明了差分格式的可解性、稳定性和收敛性,并给出了误差估计式.差分格式关于时间步长和空间步长均为二阶.在实际计算时,将引入的新变量分离开,得到仅含原变量的差分格式,降低了计算量.数值计算结果验证了理论结果的可靠性.     

刺榆的木材解剖学研究

刺榆为榆科植物，通过木材解剖学研究，发现其为环孔材，射线为同形单列及多列。     

“胶合材料学”课程教学改革初探——以华南农业大学为例

“胶合材料学”是木材科学与工程专业开设的一门重要专业基础课。以华南农业大学木材科学与工程专业为例,分析了目前存在的问题,并提出相应的举措。通过课程内容的优化、教学方法的增加、教学手段的多元化,深化学生的基础理论知识、训练分析解决问题能力、提升实践动手能力、培养创新能力,为今后的专业学习和工作打下坚实基础。