2真实齿面对应点的求解算法

针对真实齿面数学模型为自由型参数化隐式递推公式，不易于用一般方法进行迭代求解的问题，提出了将求2齿面对应点问题转换成求直线与齿面交点的王角形判断法，并进一步提出运用三角形减半法确定真实齿面精确对应点的迭代初值，得到了一种稳定、可靠、精度高且运算速度较快的求解算法。     

不同处理对蘑菇与黄豆芽混合汁营养成分的影响

采用不同工艺条件测定蘑菇与黄豆芽混合汁中营养成分的含量。经测定得知,蘑菇：黄豆芽：水：1：2：3,利用内源酶水解24h,混合汁中水溶性含氮物、VC含量较高,利用内源酶或盐酸水解可显著提高还原糖浓度。     

Effectiveness of selection for quality traits during the early stage in the potato breeding population

Potato cultivars resistant to cold‐temperature sweetening are of major importance to the processing industry producing both chips (crisps) and French fries. When most modern potato cultivars are maintained in cold storage to retard sprouting, the tubers accumulate reducing sugars, and the products become an unacceptable brown colour when fried. Selection for better processing quality during the early generations of a breeding programme could be of considerable advantage. Using a portable ‘sugarmeter’, which requires only a drop of sap from the tuber on a test strip, many samples can be efficiently surveyed for low sugar as early as the F₁ generation. Using seedlings of three test crosses, glucose and specific gravity of field‐grown tubers, minitubers from greenhouses and microtubers from in vitro culture were compared after cold treatment. Although the mean glucose levels of minitubers and microtubers were higher than field‐grown tubers, the correlation between the glucose contents of the three types of tubers was fairly high. A considerable genetic improvement was noted when progenies were grown as minitubers or microtubers, even though the response to selection for low glucose levels in minitubers and microtubers was lower than from direct selection from field‐grown tubers. The specific gravity of field‐grown tubers showed a significant association with freshly harvested minitubers and microtubers. Selection for low glucose content in minitubers can therefore save considerable resources in a breeding programme.     

农田土壤N2O排放和减排措施的研究进展

氧化亚氮(N2O)是一种受人类活动影响的重要温室气体。农业土壤是其主要的排放源之一,土壤中硝化和反硝化作用是N2O产生的主要过程。N2O的排放受多种因素的影响,农业活动尤其是施用化学氮肥是农田N2O排放量增加的主要因素。提高氮肥利用率,使用硝化抑制剂等措施将有助于减少N2O的排放量,更有效的减排措施还有待进一步的研究与应用。     

农业旱灾脆弱性评价及生态减灾研究——以湖南省衡阳市为例

农业旱情是农业旱灾脆弱性和干旱风险性共同作用的结果。随着全球变暖,蒸发力增大,干旱的风险性变大,因此降低农业旱灾脆弱性是防旱抗旱的重要措施。灾害脆弱性可以看成是生态安全性的另一面,故加强生态安全建设可以降低农业旱灾脆弱性。衡阳市是湖南省重要的农业生产基地之一,也是农业旱情较重地区之一,而其农业旱情与农业旱灾脆弱性密切相关。这种脆弱性是生态环境因素和社会因素在一定的时空条件下偶合的产物。详细地分析了气候因素、植被和土壤等环境因素和水利设施、经济发展水平等社会因素在农业旱灾脆弱性形成中的作用。依据长时间序列的气象资料和经济统计数据,运用数学模型和有关优化分析方法,对衡阳市农业旱灾脆弱性进行定量评估。提出了降低农业旱灾脆弱性的生态措施。     

水稻田土壤硫酸盐还原活性的测定及其影响因子的研究

用显色比色测定法研究影响测定黄松稻田土壤硫酸盐还原活性的因素。结果表明水稻田土壤的含水量、培养温度和时间、硫酸盐的加入量和碳源物质对测定水稻田土壤硫酸盐还原活性有显著性影响。显色比色法测定水稻田土壤硫酸盐还原活性的最适条件为:土壤含水量(W/W％)在35％左右、培养时间为24h、培养温度为28℃、加入硫酸钠的最适量应在500μg/g干土左右。     

长江中游水稻土潜育作用的特点

The gleyization of representative paddy soils in the middle reaches of the Yangtze River was characterized, taking oxidation-reduction potential(Eh), the amount of active reducing substances and the forms of iron and manganese as the parameters. The Eh value was linearly related with the logarithm of the amount of active reducing substances, which was contributed by ferrous iron by 83% on an average. The degree of gleyization of different horizons was graded as ungleyed, slightly gleyed, mildly gleyed and gleyed. The Eh of the four grades was > 500, 300-500, 100-300 and < 100 mV, respectively, and the corresponding amount of active reducing substances was < 1, 1-7, 7-30 and > 30 mmol_c kg^-1, respectively. The amount of ferrous iron of the four grades was < 0.5, 0.5-5, 5-25 and > 25 mmol kg^-1, respectively. The extent of gleyization of a soil was classified as upper-gleyed, middle-gleyed and lower-gleyed, depending on whether the depth of the gley horizon was less than 30 cm, 30-60 cm or more than 60 cm.     

降解稻草纤维素真菌的初步研究

从自然腐烂的稻草秸秆中分离筛选出126霉菌菌株,并从中筛选出10株降解稻草秸秆能力较好的菌株。其中以A242,A251降解秸秆纤维素能力较强;A321,B311降解秸秆半纤维素能力较强。A242,B311菌株的稻草粉发酵降解液中还原糖质量分数分别达到94.104 4,90.627 4 mg/g稻草粉;A321,B321菌株的稻草粉发酵降解液中木糖质量分数分别达到11.821 0,12.121 9 mg/g稻草粉。可综合其各自发酵的优势,将其作为初始菌株进行进一步的优化。     

木质纤维素稀酸糖化研究初探

木质纤维素的分解利用对于解决未来的能源危机与环境问题具有重大意义。以脱脂棉、滤纸模拟生物质的主要组分之一纤维素，在不同稀硫酸浓度、时间和温度反应参数下，进行纤维素水解糖化试验研究，以还原糖量为指标，考察纤维素糖化最佳反应条件。研究结果表明，在加热时间为60min时，还原糖得率随硫酸浓度的增加而增加；在加热时间为80min时，还原糖得率在硫酸浓度4％处出现最大值。综合硫酸及废液处理成本考虑，得到实验最佳条件为4％硫酸加热80min。     

城市森林对热污染及人体舒适度影响的研究

系统研究了城市森林对热污染的影响。结果表明，城市森林可改变下垫面性质，有效地减少到达地面的太阳辐射，在片林和林荫道下，夏季能降低气温３℃左右，路面温度７℃，建筑物表面温度４～１０℃，减少高温持续时间３～８ｈ左右。不同绿化形式，不同行道树结构，不同树种的降温效应不同，作者根据人体对气候要素的综合反应，建立了夏季城市森林对人体舒适度小气候函数方程，为城市森林效益评价提供了理论依据。