紫甘薯多酚氧化酶性质探讨

甘薯是世界上一种重要的粮食和能源作物,由于加工过程中其组织中的多酚氧化酶易催化多酚类物质氧化成黑色素,严重影响了其加工品质.以济薯18为材料,研究了pH值、温度、底物浓度等对其多酚氧化酶(PPO)活性的影响.结果表明:紫甘薯济薯18中PPO活性在360 am处最大,其最适反应时间为11 min,最适pH值6.5,最适温...     

气动关节人工手的研究

提出了一种气动关节人工手。通过人手解剖学对手结构和运动分析，设计出了气动弯曲关节和气动球关节，并通过这些关节的串并联设计出了一只气动关节人工手。研究结果表明这些气动关节可用专用电气数字压力阀得以控制。认为对这种人工手的研究和开发具有广阔前景。     

Correlation between earthworms and plant litter decomposition in a tropical wet forest of Puerto Rico

Earthworms are recognized to play an important role in the decomposition of organic materials. To test the use of earthworms as an indicator of plant litter decomposition, we examined the abundance and biomass of earthworms in relation to plant litter decomposition in a tropical wet forest of Puerto Rico. We collected earthworms at 0–0.1 m and 0.1–0.25 m soil depths from upland and riparian sites that represent the natural variation in soils and decomposition rates within the forest. Earthworms were hand-sorted and weighed for both fresh and dry biomass. Earthworms were dominated by the exotic endogeic species Pontoscolex corethrurus Müller; they were more abundant, and had higher biomasses in the upland than in riparian sites of the forest. Plant leaf litter decomposed faster in the upland than riparian sites. We found that earthworm abundance in the upper 0.1 m of the soil profile positively correlated with decomposition rate of plant leaf litter. Ground litter removal had no effect on the abundance or biomass of endogeic earthworms. Our data suggest that earthworms can be used to predict decomposition rates of plant litter in the tropical wet forest, and that the decomposition of aboveground plant litter has little influence on the abundance and biomass of endogeic earthworms.     

A nitrogen dynamic hydroponic culture on performance and quality of water spinach (Ipomoea aquatica)

Abstract

In view of the unreasonable application of chemical fertilizers in agriculture and the groundwater pollution caused by nitrogen (N) leaching, a nitrogen dynamic hydroponic culture was used to simulate the dynamics variation of ammonium nitrogen (NH₄-N) and nitrate nitrogen (NO₃-N) in the leaching loss soil. Solutions with different ratio of NO₃-N and NH₄-N (100:0, 70:30, 50:50, 30:70 and 0:100) were prepared as well as the same solutions that not containing NO₃-N .Water spinach was chosen to culture in the two solutions that differ from NO₃-N every two (E2) or five days (E5) to observe the growth, quality and nutrient solution uptake. In terms of the growth, uptake of N source, N use efficiency and the chemical indicators, plants grown in the balanced solution all showed the best results. The nitrogen dynamic hydroponic culture showed some differences between E2 and E5 in some aspects. Under the same N source level, plants in E2 showed a better growth and higher NO₃-N uptake than E5. On the other hand, the uptake of NH₄-N seemed to be affected significantly by the interchanged frequency, which showed the same variations of glutamine synthetase activity. The activity of nitrate reductase and glutamine synthetase showed the coexist of NO₃-N and NH₄-N could play synergistic effect. It is not recommended to supplement NO₃-N frequently in the case of N leaching loss, which has little impact on the growth and may lead to the hard taste and groundwater pollution.     

柞蚕粉微胶囊化制备工艺的研究

为了更好得开发利用柞蚕资源，该文通过对微胶囊壁材的初选试验和包埋工艺的研究，确定了以spo-mo350变性淀粉、阿拉伯胶做为壁材，以柞蚕粉做为芯材，利用喷雾干燥的方法制备柞蚕粉微胶囊。通过正交试验确定微胶囊包埋最佳工艺参数为：spo-mo350变性淀粉/阿拉伯胶的质量比为4∶1，进风温度180℃，出风温度115℃，芯材/壁材的质量比为1∶1，壁材占乳化液比例30%，包埋率达86.4%。该微胶囊包埋工艺能够较好的解决柞蚕粉存在的腥味重、易氧化等问题，使其具有更广阔的应用前景。     

渠道运行神经网络控制

针对渠道运行的不确定性和非线性，在渠道自动控制系统的观测器回路上并联一个BP神经网络，通过实测水位的学习，修正控制系统数学模型的不准确性；在控制器增益回路上并联一个BP神经网络，补偿控制增益的不精确。与传统的线性二次调节(LQR)最优控制相比，渠道运行控制过渡过程更为平稳，达到稳定的时间缩短，闸门运行的振动和超调大为改善。     

河南省大豆审定品种系谱来源及性状分析

为明确河南省大豆审定品种亲缘关系,借鉴有益于育种效果的经验与技术,分析了河南省1985—2012年审定的74个大豆品种的系谱来源、主要农艺性状和经济性状特点。结果表明,河南省审定的大豆品种可明确113个原始亲本,产量与原始亲本数量成显著正相关。河南省大豆审定品种的主要农艺性状中,生育期稳定在106 d左右,株高因品种而异,变化较大;产量构成因素中,单株荚数总体呈增加趋势,百粒质量则相对变化较小。113份原始亲本中,来自河南省及周边省份的原始亲本占总数的50%以上,各审定品种之间血缘关系过于密切。河南省大豆品种合理的产量构成因素应该是:单株荚数48.6个左右,百粒质量17.55~21.80 g。     

逐步判别分析在中国烤烟香型鉴定中的应用

分析云南、河南、辽宁烤烟的多项化学成分含量,并对烤烟进行专家评吸香型鉴定。以化学成分为自变量对不同香型烤烟进行逐步判别分析,构建判别函数,并对判别函数的判别效果进行检验。结果表明,总糖、还原糖、烟碱、钾等8个变量进入判别函数,由判别函数的方差分析可知判别函数具有显著意义;用自身验证法和交互验证法对原样品进行回判,回判的准确率分别达95.5%和94.3%,新样品的判别准确率达93.3%,判别效果良好,在实际应用中值得推广。     

小麦丛矮病(NCMV)寄主范围的研究

 为了探明小麦丛矮病的寄主范围,用带毒灰稻虱(Laodelphax striatella Fallen)接种,然后用无毒灰稻虱若虫回接,同时结合血清学反向炭凝法检测,共计测定29属70种禾谷类作物和杂草。结果有16属53种禾本科植物是本病毒的寄主,其中42种是我们新证实的寄主植物。     

春用蚕品种繁花、春梅的育成研究

采用杂交、系统选育和活蛹缫丝等育种方法，经１０年的选择和培育，育成了茧丝量多，茧丝质较优的中系皮斑限性品种繁花和日系品种春梅，其一代杂交种经多次实验室鉴定和省鉴审定表明：强健好养、茧丝质优、虫蛹率和万蚕产茧量分别比对照种提高５．６％和１５．２１％，茧丝长和解舒丝长分别增加９０．２米和７６．３米，净度９３．４２分。