以户为生产单元 农业通用性专家系统的构建

专家系统是利用计算机、模拟人类专家解决专门问题的软件。本文阐述了集中张北旱农试区有关学科专家指导农户生产与经管经验,而编制的以户为生产单元通用性专家系统。该系统针对我国当前农业生产方式,具有较强的实用性;采用菜单驱动、汉字显示,具有良好的界面。     

Small-diameter silicon nanowire surfaces

Small-diameter (1 to 7 nanometers) silicon nanowires (SiNWs) were prepared, and their surfaces were removed of oxide and terminated with hydrogen by a hydrofluoric acid dip. Scanning tunneling microscopy (STM) of these SiNWs, performed both in air and in ultrahigh vacuum, revealed atomically resolved images that can be interpreted as hydrogen-terminated Si (111)-(1 x 1) and Si (001)-(1 x 1) surfaces corresponding to SiH3 on Si (111) and SiH2 on Si (001), respectively. These hydrogen-terminated SiNW surfaces seem to be more oxidation-resistant than regular silicon wafer surfaces, because atomically resolved STM images of SiNWs were obtained in air after several days' exposure to the ambient environment. Scanning tunneling spectroscopy measurements were performed on the oxide-removed SiNWs and were used to evaluate the electronic energy gaps. The energy gaps were found to increase with decreasing SiNW diameter from 1.1 electron volts for 7 nanometers to 3.5 electron volts for 1.3 nanometers, in agreement with previous theoretical predictions.     

亚麻胶的研究

亚麻种子的种皮占种子干重的４５％左右，且种皮的５５％是胶质，约占干种子的２５％左右，这种胶属酸性粘胶，简称亚麻胶。该胶可用水、碱、酸提取，提取量与水解温度和时间有关，胶的酯化度和甲氧基含量与提取温度有关。     

NaCl和Na2SO4胁迫对蒲公英种子发芽及成苗的影响

以蒲公英种子为试材，在NaCl和Na2SO4盐溶液中发芽，幼苗在持续盐胁迫条件下成苗生长。结果表明，当浓度为3500mg／kg时，NaCl和Na2SO4分别严重抑制了蒲公英种子的发芽，达到极显著水平。NaCl对种子发芽率的抑制强于Na2SO4。蒲公英成苗胁迫试验中，NaCl，Na2SO4浓度分别为5000mg／kg时，严重影响蒲公英成苗率、幼苗根、茎的生长和鲜干重比值，对叶绿素含量影响不大。种子发芽期问适当浓度的NaCl和Na2SO4盐溶液胁迫有助于诱导蒲公英幼苗耐盐性的产生。     

应用间接血凝试验检测牛肺疫抗体

自制1.5％绵羊红细胞诊断液并用于检测牛肺疫抗体,结果如下:(一)三批标准阳性血清(批号为8601、8301、8001)凝集价均在160倍以上,标准阴性血清(批号为8601)凝集度仅为10倍。15份被检血清IHA的阳性检出率(8/15)高于补体结合反应(CF,6/15)且凝集价均在40倍以上。(二)用牛肝片吸虫病、布氏杆菌病和附红细胞体病阳性血清作类症鉴别诊断,凝集度仅为10倍。(三)把牛肺疫CF8502抗原作倍比稀释,加2个凝集单位牛肺疫阳性血清8601和8301进行间接血凝抑制试验,分别被32倍和16倍稀释的抗原所抑制,本项试验结果表明IHA用于检测牛肺疫,具有检出率高、特异性强、设备要求简单、容易操作等特点,适于在现地推广应用。     

Study on polymorphisms of microsatellite DNA of six Chinese indigenous sheep and goat breeds

The genomes of six populations were screened using microsatellites as molecular markers, including Ujmuqin sheep, small-tailed Han sheep, Tan sheep, Hu sheep, Tong sheep and Yangtse River Delta (YRD) white goat. A total of seven microsatellite markers were used and genetic diversity and genetic distance were also determined. The results showed that there were 224 alleles in six populations, all seven loci showed polymorphism in all populations. The average heterozygosity of all populations was 0.949 9, and the mean polymorphism information content (PIC) of all six populations was 0.842 5–0.929 4. The six sheep (goat) popualtions were lowly differentiated with all loci, and the coefficient of phaenotype differentiation (Fst) was 2.6%, which was consistent with the coefficient of gene differentiation (Gst). The global heterozygote deficit across of all populations (Fit) amounted to 0.5%. The overall significant deficit of heterozygotes because of inbreeding within breeds (Fis) amounted to −2.2%. Two Unweighted Pair-group Method using Arithmetic Averages (UPGMA) dendrograms were constructed on the basis of Nei’s standard genetic distance (DS) and Nei’s genetic distance (DA) respectively. Hu sheep and Tong sheep were grouped at first, Ujmuqin sheep and small-tailed Han sheep clustered and then clustered with Tan sheep. Finally, Yangtse River Delta white goat joined in with all above. From this study, Ujmuqin sheep belongs to “Mongolia sheep” group, which corresponds with the historical records exactly. Ujmuqin sheep and small-tailed Han sheep, Tan sheep, Hu sheep and Tong sheep all vest in the “Mongolia sheep” group.     

中国自然科学论文作者的简要统计分析

按国际文献计量学研究的通行做法,论文的归属按第一作者所在的地区和单位确定。通过对作者群的学科分布,机构分布,地区分布,高产、高影响作者群分布等统计,分析我国科研队伍发表论文现状。目前,我国作者群的学科分布不均匀,高产作者群,特别是国际论文的高产作者群主要分布在化学、物理、生物和数学等学科。作者群的地区分布不均匀,特别是地域广大、跨13个省(市)的大西北论文作者数,无论是国际或国内论文的比例都不足16%。高产作者群的4/5分布在我国高等学校。     

不同海拔野生金露梅叶的成分分析

金露梅灌木林是青海最大的灌木林区之一。目前对金露梅叶片的研究仅限于解剖结构、灌丛地上部分生物量和黄酮类物质的研究,对青海野生金露梅叶成分整体研究少。2005年7月在海拔2840m和2510m处采野生金露梅叶作为样品进行成分分析,结果表明:样品在海拔2840m处黄酮的含量高于样品在海拔2510m处的含量;单宁的含量相当;样品在海拔2840m处还原糖的含量高于样品在海拔2510m处的含量,粗蛋白的含量低于样品2510m处的含量。     

半干旱地区杨树新品种选育初报

通过青杨派的种间杂交,在半干旱地区的杨树新品种选育中,初选出四龄树的金科5号优良无性系。对金科5号在耐干旱、耐盐碱、速生等方面的特性进行了试验研究,发现其表现优良,适于在兰干旱地区推广。     

农业科研单位会计电算化发展探索

文章通过分析农业科研单位会计电算化存在的问题,提出了解决途径,即发挥会计人员财务管理上的作用;提高财务人员综合素质;充分利用会计电算化的财务管理功能,发挥软件管理优势;加强会计电算化网络化建设,提高会计信息的利用率。