毛竹材微纤丝角变异规律研究

利用了X射线衍射技术对不同高度、不同竹龄、在垂周方向不同位置的毛竹材微纤丝角变化规律进行了研究。结果表明,在竹壁径向上,由外而内,微纤丝角大致呈先增大后减小的变化趋势,至靠近竹黄处微纤丝呈现最小值,且最大值与最小值间差异为4.17°。从基部往上,微纤丝角有略微增大,最大差异只有0.15°。毛竹材的微纤丝角从0.5年至6年呈先增大后减小的变化趋势,5个竹龄的毛竹材微纤丝角之间的差异最大值仅0.52°。最后通过方差分析表明,高度、竹龄以及垂周方向上的位置对毛竹材微纤丝角的影响显著。     

棉纤维X射线衍射谱计算分峰法研究

应用ＳｐｉｎｌａｂＨＶＩ９００测试仪和Ｘ射线衍射谱的计算分峰法测量了棉纤维品质性状和取向参数。初始弹性模量（Ｍ，Ｎ／ｔｅｘ）、３．２ｍｍ隔距比强（Ｔ，ｇｆ／ｔｅｘ）、２．５％跨距长度（Ｌ，ｍｍ）与微原纤螺旋角（φ）、纤维素微晶取向离散角（α）存在如下关系：Ｍ＝３．７３－０．０４φ－０．０６α，ｒ＝０．７６２；Ｔ＝５８．０８－０．３０φ－１．３３α，ｒ＝０．８７６；Ｌ＝６３．２３＋０．５７φ－１．８８α，ｒ＝０．９０５。陆地棉原棉纤维的５０％Ｘ射线角ψ对φ的比ψ／φ约为２．０４，ψ／φ值对于不同棉种具有高度的单一性。     

叶面喷施“东农一号生长素”对亚麻产质量影响的研究

亚麻枞形期末至快速生长期初,叶面喷施“东农一号生长素”,原茎增产１８．０％,纤维增产２３．０％,长麻率增加２．５％,纤维强度增加２．７６ｋｇ,麻号提高产１＃。因此,“东农一号生长素”对亚麻有增加产量、改善纤维品质的效果。     

杂交改良对撒坝猪肉品质的影响——肌肉食用品质及肌纤维特性分析

 研究选用24kg左右的去势撒坝猪及其约长撒三元杂交猪各7头，根据基因型分成两组, 按活重变化分为3个试验期 （前:20～35kg，中: 35～60kg和后期60～90kg），在同一试验期内饲喂同样的日粮进行饲养试验，当活重达90kg进行屠宰试验，研究杂交改良对云南省本地猪种撒坝猪肉品质和肌纤维特性的影响。撒坝猪通过杂交改良后，生长速度和瘦肉率显著提高，但其肉品质均有不同程度的下降。杂交后代肌肉水分显著地增加（P<0.01），相反，肌肉粗蛋白（P<0.05）、粗脂肪和肌内脂肪（P<0.01）显著地降低。杂交后代的系水率、保水率、肉色、嫩度等指标均有不同程度的下降（差异不显著P>0.05），然而，大理石纹、熟肉率、滋味、多汁性和汤味显著下降（P<0.05）。肌纤维直径和密度变化较为显著。杂交后显著地降低了腰肌、股二头肌和背最长肌肌纤维密度（P<0.001）；腰肌、股二头肌和背最长肌肌纤维密度分别降低了22.3%，22.8%和19.3%。肌纤维密度降低的主要原因是杂交后显著地增加了腰肌、股二头肌和背最长肌肌纤维直径（P<0.01）；腰肌、股二头肌和背最长肌肌纤维直径分别增加了22.5%，18.1%和18.9%。     

Cone beam computed tomography and intraoral radiography for diagnosis of dental abnormalities in dogs and cats

The development of veterinary dentistry has substantially improved the ability to diagnose canine and feline dental abnormalities. Consequently, examinations previously performed only on humans are now available for small animals, thus improving the diagnostic quality. This has increased the need for technical qualification of veterinary professionals and increased technological investments. This study evaluated the use of cone beam computed tomography and intraoral radiography as complementary exams for diagnosing dental abnormalities in dogs and cats. Cone beam computed tomography was provided faster image acquisition with high image quality, was associated with low ionizing radiation levels, enabled image editing, and reduced the exam duration. Our results showed that radiography was an effective method for dental radiographic examination with low cost and fast execution times, and can be performed during surgical procedures.     

Sulphur speciation and turnover in soils: evidence from sulphur K-edge XANES spectroscopy and isotope dilution studies

Sulphur K-edge X-ray absorption near edge structure (XANES) spectroscopy was used to quantify S species in humic substance extracts from ten soils from the UK, China and New Zealand, which differ in land use and agricultural management. XANES spectroscopy showed the presence of most reduced (sulphides, disulphides, thiols and thiophenes), intermediate (sulphoxides and sulphonates) and highly oxidised S (ester sulphates) forms, with the three groups representing 14-32%, 33-50% and 22-53% of the organic S in the humic substance extracts, respectively. Land use had a profound influence on the relative proportions of S species. Well-drained arable soils generally had a higher proportion of organic S present in the most oxidised form than the grassland soils collected nearby, whereas paddy soils showed a more reduced profile due to episodic flooding. In the Broadbalk Classical Experiment at Rothamsted, reversion of an arable system to grassland or woodland in the 1880s resulted in an increase of the most reduced and intermediate S species at the expense of the most oxidised S species. Long-term applications of farmyard manure to an arable plot also shifted S species from the most oxidised to the intermediate and the most reduced species. Sulphur immobilisation and gross mineralisation were determined in seven soils using the ³⁵S isotope dilution method. Gross mineralisation during a 53-day incubation correlated more closely with the amounts of the most reduced and intermediate S species than with the most oxidised S species, suggesting that the former (C-bonded S) were the main source of organic S for mineralisation in the short-term.     

pH对针铁矿表面磷酸盐吸附的化学形态的影响

Chemical forms of the phosphate adsorbed on goethite surfaces and characteristics of the coordinate groups which exchange with P on goethite surfaces in solutions with different pll values were investigated.Results showed that the chemical forms of P on goethite surfaces changed from the dominance of monodentate corrdination to that of bidentate one with increasing pH of the solution.By influencing types of phosphate ions in solutions,pH affected the chemical forms of P on goethite surfaces,The amount of OH^- displaced by phosphae on goethite surfaces was the most at pH 7.0,the second at pH 9.0,and the least at pH 4.5.     

X射线强度直接计数法无损检测木材生长轮密度

文中初步探讨了X射线强度直接计数法无损连续检测木材生长轮密度的理论。作者主要根据X射线服从指数衰减规律,采用按一定步长移动的扫描方式,并结合应用D/max-3B型X射线衍射仪(日本)提出了试样制作要求和试验方法。通过实验对兴安落叶松、杉木等进行了测试,其结果与称重法比较基本一致。这一研究表明,应用X射线强度直接计数法,优于X射线照像法和γ射线强度直接计数法,它简化了测试过程,提高了检测速度,是一种检测木材密度的有效手段,可用于木材科学研究和生产实践。     

无引发剂接枝聚合对丝素蛋白纤维性能的影响

通过对不同接枝率的丝素蛋白纤维的耐水洗性、吸湿性、力学性能、热稳定性及染色性等的研究和分析 ,探讨了无引发剂条件下甲基丙烯酸甲酯 (MMA)与丝素蛋白纤维接枝聚合对丝素蛋白纤维性能的影响。结果表明 :接枝聚合后丝素蛋白纤维有良好的耐水洗性 ,力学性能、热稳定性均有提高 ,吸湿性下降不明显 ,染色性有所提高 ,接枝率 2 6 %左右吸色深度最大。     

碳纤维人工食管用于牛羊的实验研究

选用碳纤维作为食管代替物,对各切除颈段固有食管3～4cm的8例绵羊和2例犊牛行食管植入吻合术。植入的碳纤维人工食管长度为3～4.5cm,管径为1～2cm,管壁厚为0.1～0.15cm。人工食管与食管断端采用作者改进的高桥氏二层重叠缝合方法吻合。术后除2例绵羊因人工食管渗漏子第4d死亡外,其余吻合手术均获成功。绵羊术后4～5d采食咀嚼碎青草自如,但咽下较缓慢,有时反复2～3次方能咽下;术后5～20d,采食及吞咽恢复至正常状态;20d后又复出现吞咽缓慢。犊牛术后饮奶咽下顺利,到20d后偶有反复吞咽和奶汁由鼻孔中返流现象,经3～5d恢复正常。经X线透视或钡剂食管造影检查,术后7～14d,钡液顺利通过食管和人工食管,显示人工食管部较正常食管稍细,术后22～26d,人工食管脱落,脱落部食管狭窄,其前方食管呈纺锤状扩张。动物全身及血液,生化指标观察均无明显改变。病理学观察,术后15d可见在食管两断端由新生肉芽组织形成纤维膜管以包裹人工食管,在新生肉芽组织纤维膜管内面,靠近食管吻合口边缘,已长出灰白色薄层粘膜;术后22～25d,人工食管脱落于瘤胃或网胃中,食管缺损段已由新生的食管组织连接在一起,新生食管外周形成纤维膜包裹,管腔内面被覆有较完整的薄层粘膜;术后35～40d。见新生食管内面粘膜层覆盖完整,管壁稍增厚,内腔稍