兴安落叶松规格材齿板连接节点的拉伸性能

采用国产落叶松规格材及进口齿板连接件构造节点,依据国标对齿板接合节点的延性比、齿极限承载力、齿板极限受拉承载力及设计值进行评估。结果表明,采用Foschi公式对试验曲线进行拟合,结果良好;齿板节点的延性比随节点构造方式的不同而异,顺纹节点的延性比均大于2.0,明显高于横纹节点,符合抗震结构的要求。     

水土保持产业化的精品水果高新技术发展策略

水土保持产业化的精品水果高新技术发展首先必须有自己的基地,这样才能保证品种的优良特性,在发展水土保持精品水果高新产业时,科学规范、合理布局,多元化发展名特优果类,按"销-供-产"的生产方式,通过市场规模,调整生产规模,这样,才能在激烈的市场竞争中取胜.     

陕西农田土壤动物群落与长期施肥环境的灰色关联度分析

2001年7月至2002年10月,对陕西黄土区6种长期定位施肥农田土壤动物群落进行调查,采集72个定点土壤样品,通过手捡法和Cobb过筛法,共获得农田土壤动物标本5495只,隶属6门11纲22目;分析测定了土壤环境中的3类土壤微生物(细菌、真菌和放线菌)和土壤因子的5项指标(耕层全N、有机质含量、有效P、pH、土壤含水率)。以长期定位施肥农田土壤动物5种优势类群、弱势类群以及农田土壤动物个体数为研究对象,应用灰色理论对长期定位施肥农田土壤动物群落与土壤环境之间的灰色关联系数和灰色关联度进行了分析。结果表明,本研究选取的环境因子与农田土壤动物因子的关联表现出一定的规律性,土壤pH和含水量对土壤动物个体总数的影响最大。对农田土壤动物的影响的大小顺序为:全N有机质含水量pH细菌真菌放线菌有效P。优势分析显示,土壤有机质对土壤动物的影响最大,土壤全N的影响次之,其灰色综合关联系数分别为0.6555和0.6444;细菌的影响最小,其灰色综合关联系数为0.5429。土壤因子对农田土壤动物的影响大于土壤微生物。     

介电特性在粮食含水率检测中的应用研究

根据农业物料的含水率对其相对介电常数等电参量的影响关系，对水稻、玉米和大豆等3种物料的含水率进行了标定试验，提供了测定含水率的一种更为简单、易行的方法，对物料电特性与介电常数、含水率的函数关系进行了分析和研究。通过相关研究，提出进一步的解决方案。     

声卡和LabVIEW在农机测试中的应用

声卡是个人电脑中不可缺少的一部分,同时也是一个很好的A/D,D/A卡;LabVIEW是一个功能强大的数据分析、处理和控制的工程实用软件.将二者相结合构造了一个完整的数据采集系统应用在农机测试中.实践证明,该系统结构简洁、操作方便、构思新颖、通用性强,它可实现长时间、大容量的数据采集,可以更好地为我国农业机械化事业服务.     

Impact of Long-Term Fertilization on Cropland Soil Fauna Community at Loess Soil, Shannxi, China

The relationship between long-term fertilization and cropland network for soil fertility and fertilizers in Loess soil of Shannxi soil fauna was studied at the station＇s experiment research Provincefrom Jul. 2001 to Oct. 2002. Six types of long-term fertilizer were carried out for this study including non-fertilizer （CK）, abandonment （ABAND）, nitrogenous and phosphors and potassium fertilizers combined （NPK）, straw and NPK （SNPK）, organic material and NPK （MNPK） and 1.5 times MNPK （1.5MNPK）. 72 soil samples were collected and 5 495 species of cropland soil fauna obtained by handsorting and Cobb methods at 4 times, belonging to 6 Phyla, 11 Classes, 22 Orders, 2 Superfamilies, 61 Families and 35 Genera. The result showed that different fertilizer had significantly impacted on the cropland soil fauna （F = 2.24, P〈0.007）. The number of the cropland soil fauna was related to the soil physicochemical properties caused by long-term fertilization. The result by principal component analysis, focusing on the number of 15 key soil fauna species group＇s diversity, evenness of community and the total soil fauna individuals indicated that the effects of SNPK, NPK, MNPK and 1.5MNPK were significantly different from that of the cropland soil fauna, in which, SNPK and NPK had the positive effect on cropland soil fauna, and MNPK and 1.5 MNPK had the negative affect, others could not be explained. By principal component I, the synthetic effect of different fertilization on the total soil fauna individuals and the group was most significant, and the effect was little on evenness and diversity. By value of eigenvectors, the maximum one was 9.6248, and the minimum one was - 1.0904, that means the 6 types of fertilization did not affect evenly the cropland soil fauna.     

网络环境下数字馆藏的建设

 

系统介绍了数字馆藏的含义、特点、分类及建立方式，在此基础上进一步阐述了如何推进数字馆藏建设，并指出数字馆藏建设是一项复杂的系统工程，需要各方面因素的协调配合。

     

有机-无机肥料配合施用对塿土的培肥效果

通过12年长期定位试验研究了有机-无机肥料配施对土耕层土壤有机质、全氮、全磷、全钾、速效氮、速效磷、速效钾以及土壤的容重、田间持水量、土壤孔隙度的变化。结果表明,化肥配施秸杆与有机肥均能提高土壤肥力,但效果不同;与长期施无机化肥的NPK相比较,M(H)NPK、M(N)NPK培肥效果明显好于SNPK,以有机质提高最为显著。     

The Relationship Among Photoinhibition, Photooxidation and Early Aging at a Late Development Stage in Different Varieties with High Yield

Using six high yield varieties from different ecological districts in China the parameters of Chl fluorescence, the performance of membrane lipid peroxidation and the reduction of Chl content in flag leaf under natural condition at the later developmental stages (from heading stage to mature stage). The results showed that Fv/Fm, decreased gradually, the excessive light energy led to the accumulation of active oxygen O2-, H2O2 and the product of membrane-lipid peroxidation, MDA, which resulted in the reduction of Chl content and early aging due to photooxidation during the course of senescence of flag leaf. This phenomenon varied obviously in rice varieties. When comparina japonica tolerant to photooxidation, Fv/Fm in indica shanyou 63 susceptible to photoxidation decreased significantly. An increase of active oxygen and a sharp drop of Chl content, resulted in “yellowish“ early aging and influenced filling and setting of rice grain. The mechanism on early aging in indica was related to light and temperature conditions in filling stages. On a fine day (above 25℃ ), PS Ⅱ reaction center exhibited a dynamic change on revisable inactivation. Under strong midday light, PS Ⅱ function in indica exhibited obvious down-regulation and photoinhibition; Under strong light with low temperature, PS Ⅱ resulted in photodamage, showing early aging, which were related to the degradation of PS Ⅱ - D1 Protein and the inhibition of the endogenous protecting system such as Xanthophyll cycle and the enzymes of scavenging active oxygen. The results suggested that for a view of high-yield breeding, on the basis of a good type-plant, giving consideration to the utilization of heterosis and resistance to early aging, selecting japonica or a sterile line with japonice genotype as maternal was a breeding strategy worthy of being paid more attention.     

小麦胚乳淀粉合成酶基因研究进展

很多研究表明。小麦胚乳淀粉的合成至少需要四类酶——腺苷二磷酸葡萄糖焦磷酸化酶、淀粉合成酶、淀粉分支酶和淀粉去分支酶，这四类酶的基因克隆和特性的研究有重要进展。目前，已从六倍体小麦发育胚乳的eDNA文库中获得AGPase两个亚基、gbssⅠ、ssⅠ、ssⅡ、ssⅢ、sheⅠ、sbeⅡ和sul(dbe)等基因的cDNA；从六倍体小麦的D组供体Triticum tauschii基因组文库中获得ssⅠ、ssⅠ、ssⅢ、sbeⅠ和sbeⅡ的gDNAs；从六倍体中只获得野生型和突变型的gbssⅠ(wx)基因。除编码AGPase大亚基的基因和sul基因未进行定位外，ssⅢ位于第一群染色体上，sheⅡ位于2DL上，其余基因均位于第七群染色体上。