Moisture Controls Growth of Birch at Upper Timberline in Southern Himalayas

<正>Birch(Betula)trees and forests are widely distributed across much of the temperate and boreal zones of the Northern Hemisphere.Despite being an ecologically significant genus,it is not well studied compared to other genera like Pinus,Picea,Larix,Juniperus,Quercus,or Fagus.Prof.LIANG Eryuan and his colleagues from the Institute of Tibetan Plateau Research     

中国特殊煤种——树皮煤的研究进展

树皮残植煤为我国华南晚二叠世特殊煤种之一,具有高挥发份、低水分、高硫(尤其有机硫)、高熔融性、高溶胀性和高焦油产率等特点。针对树皮残植煤的研究,从上世纪30年代开始距今已有80余年,取得了一定进展。本文对树皮残植煤的研究进行了概括和总结,并基于此,对其进一步研究提出了建议。     

用高等植物监测大气中的二氧化硫

通过测定天津常见高等植物树种白杨、垂柳的树皮中的pH值,研究大气中SO2的含量对树木pH值的影响。结果表明,大气中污染对植物pH值影响较大。树皮pH值与大气酸性污染物含量呈显著的负相关。     

沙棘茎皮提取液稳定性的研究

分光光度法研究了沙棘茎皮提取液的稳定性。结果表明:该提取液热稳定性较好,对光照较为敏感,室内自然光下7天降解37%。pH值为2～8时对提取液影响不大,所以该提取液可在酸性和弱碱性条件下避光长期保存。除Fe3 和Cu2外,金属离子Mg2 、Na 、Mn2 、Ca2 对提取液影响不明显。该提取液对氧化剂H2O2、还原剂Na2SO3耐受能力较强。     

对城市商业银行跨地区发展的思考

本文论述了城市商业银行跨地区发展的可行性,分析了其发展的背景、特征和应注意的解决的几个问题。作者认为跨地区发展虽然是城市商业银行的发展方向,但不是最佳选择。     

红麻剥麻理麻联合作业机的试验研究

针对红麻生产中存在的“老大难”问题,提出了集自动喂入,剥麻,理麻为一体的红麻联合作业机设计思路,并对各主要部件进行了试验研究,验证了其方案的可行性,掌握了主要结构及运动参数对工作性能的影响规律,为进一步的整机开发提供了参考依据。     

白鲜根皮与木心活性成分比较研究

目的：比较白鲜根皮和木心的活性成分,为白鲜产地加工是否需要去心提供理论依据．方法：采用HPLC法测定白鲜根皮与木心中挎酮和黄柏酮含量,并比较HPLC指纹图谱相似度．结果：根皮中的褡酮和黄柏酮含量分别为0．7731％、0．3029％,木心中的棒酮和黄柏酮含量分别为0．4712％、0．1785％;根皮与木心指纹图谱的相似度达0．923,有12个共有峰．结论：以棒酮和黄柏酮为指标,白鲜根皮中两者含量均大于木心中的两者含量;根皮与木心中两者含量均达到了中国药典要求,二者HPLC指纹图谱的吻合程度较高,活性成分相似．白鲜根皮可不去木心入药．     

基于顶空气相色谱法树皮模式识别实验的开发

开发了基于全自动顶空气相色谱技术对树皮进行模式识别的综合性实验。同时,结合计算机编程、线性代数等,通过采用主成分分析法和聚类分析等化学计量学算法,初步实现了4种不同种树皮的快速分类和识别。所开发实验突出参与性、综合性和创新性,鼓励学生全面开拓思路,选题内容不仅要结合科研领域热点,并且要贴近生活。教学方面,提升网络教学水平,重视实验总结和结果反馈。实验完善了多层次色谱实验教学体系,培养了学生运用跨学科知识处理化学问题的能力,教学效果良好。     

康县大堡镇李家山手工制造构皮纸工艺探访

甘肃康县大堡镇李家山村农民继续按最原始的造纸工艺流程生产着手工纸,传承着手工造纸这一古老的原生态文化信息。研究认为,目前传统手工造纸业的发展前景广阔,可开发利用的价值不可低估。因此,合理开发利用自然资源,发展手工业造纸在推动当地农村经济可持续发展,构建和谐社会,促进民族文化进步等诸多方面具有积极的意义。     

A study of the light sensitivity of birch bark

Birch bark is commonly found in indigenous collections in Canadian museums. It is empirically known that light can cause the cambium side of birch bark to change colour. The purpose of this research is to better assess the light sensitivities of various colours of birch barks, and the manner, degree, and rate of colour change during light exposure. Six barks with different colours were used: beige, yellow, orange, orange-brown, red, and brown. Samples were exposed to daylight through a north-facing window (window), LED light from an enclosed chamber (LED), and the Newport-Oriel microfade tester (MFT). Window and MFT samples received a total light dose of approximately 25 Mlux-hours, and LED samples, 182 Mlux-hours. Colour monitoring of the samples showed that almost all barks initially darkened and then faded. Daylight through window caused the most rapid and extensive darkening and fading. Bluewool (BW) ratings for window samples were the lowest (most light sensitive). The MFT and LED samples showed a similar degree of colour change, with the same dose, despite the difference in intensity. Ratings of MFT samples are within one BW step difference compared to LED samples. The rate and extent of initial darkening depended on the colour of the bark; the middle range orange-toned barks showed the most rapid and extensive darkening followed by fading.