锅炉循环泵的泵壳改型与应力安全分析

为降低生产成本,通过采用铸造生产代替锻造生产并且减小半球形压水室内径的措施对一种现有的锅炉循环泵的泵壳进行改型．采用Ansys Mechanical软件,参照ASME标准第Ⅷ-2卷,疲劳计算应用一般迈内尔(Miner)准则和雨流计算法,计算4种泵壳的静态强度使用系数和低循环疲劳使用系数．结果表明:4种泵壳的静态强度使用系数和低循环疲劳使用系数均小于1;内径减小至0875倍时,最大静态强度使用系数减小了7％,最大低循环疲劳系数减小了84％;壁厚增大至1375倍时,最大静态强度使用系数减小了163％,最大低循环疲劳系数增大了2214％．说明选用铸造材料代替锻造材料是应力安全的;小内径可提高静态强度性能,并显著提高低循环疲劳性能;大壁厚可显著提高静态强度性能和降低低循环疲劳性能．     

元素分析仪和全自动凯氏定氮仪法测定有机肥总氮含量对比研究

氮含量作为有机肥养分的重要来源,是评价有机肥质量的一项重要指标.文章以普通市售的有机肥料为样品,分别使用元素分析仪和全自动凯氏定氮仪测定有机肥料的全氮含量,为采用两种不同的分析测试方法测定有机肥料全氮含量研究提供可靠的技术支持.样品每个分析测试方法重复测定5次.结果 表明:元素分析仪和全自动凯氏定氮仪法测定的有机肥料全...     

基于人工鱼群算法的车辆平顺性优化分析

平顺性是汽车重要特性之一,平顺性优化分析属于组合优化问题,同时其非线性特性导致优化实质上是一个非线性多峰的优化问题,为了有效解决此类复杂优化的求解问题,近年来基于随机搜索优化算法建立了一种新型的人工鱼群算法。该文将人工鱼群算法应用到汽车平顺性优化分析研究中,以某8×4载货车为研究对象,建立9自由度汽车平顺性模型,对影响汽车平顺性的重要参数进行优化分析。优化结果表明,加速度均方根平均下降16.82%,在60 km/h时下降最大,加速度均方根下降21.24%,有效提高了重型车的平顺性能。因此,利用该模型可对汽车平顺性进行预测或评估。     

加工工艺对油茶籽油氧化稳定性及酚类物质含量的影响

为了探究加工工艺对油茶籽油营养品质的影响,了解油酚类物质在加工工艺中的变化规律,该文从油茶籽油加工企业的生产线中取样,对压榨毛油和浸出毛油精炼工艺以及压榨毛油适度精炼工艺等不同工艺中油茶籽油中总酚、多酚组成及含量、抗氧化活性系数和油的氧化诱导时间等指标进行了测定。压榨毛油精炼工艺包括水洗、脱色、脱臭、冬化;浸出毛油精炼工艺包括碱炼、水洗、脱色、脱臭、冬化;压榨毛油适度精炼工艺包括脱胶、碱炼、水洗、冬化等工艺步骤。结果显示:压榨油茶籽毛油中总酚平均质量分数为103.06μg/g,显著高于浸出油茶籽油48.52μg/g(P0.05);油茶籽毛油经过精炼工艺后总酚和总酚的抗氧化活性均呈现下降趋势,三种精炼工艺后油茶籽油中总酚分别下降了88.9%,86.7%和63.81%,总酚的抗氧化活性分别下降了88.3%,93.51%和83.25%。适度精炼相比普通精炼对于保留油茶籽油中的多酚有明显优势,前者精炼后油茶籽油中总酚及其抗氧化活性系数分别为37.82μg/g和9.33%,后者仅为11.41μg/g和4.71%。通过高效液相色谱测定发现,浸出油茶籽毛油精炼后仅含有少量肉桂酸,压榨毛油传统精炼后压榨油茶籽油中测到苯甲酸、芦丁和肉桂酸等3种多酚的质量分数分别为4.7、1.58和0.22μg/g,压榨毛油适度精炼后的油茶籽油中测到了单宁酸、绿原酸、表儿茶素等9种多酚,其中单宁酸和绿原酸的质量分数最高,分别为4.57和3.26μg/g;适度精炼后油茶籽油氧化诱导时间从初始的8.56 h增加到11.66 h,增加了26.63%;压榨毛油传统精炼后油茶籽油氧化诱导时间从8.14 h增加到10.42 h,增加了21.83%。研究结果表明,压榨毛油适度精炼相比传统精炼工艺对于保留油茶籽油中多酚等成分有明显优势,所生产的茶油具有更强的氧化稳定性。研究结果为油茶籽油中营养成分的保留提供了途径,为油茶籽油加工工艺选择提供参考。     

福建农业竞争力的指标评价与动态分析

首先从省域农业竞争力理论回顾与文献述评入手,笔者在省域农业竞争力评价模型选择和指标体系设计的基础上,通过对福建省域农业竞争力的综合评价与竞争力演变趋势分析,揭示各级指标的变化态势与变化成因,最后提出培育福建农业竞争力的对策研究,为政府决策提供一定参考。     

Estimation of Cleaner Production Potential

The term Cleaner Production(CP)and Estimation of Cleaner Production Potential are introduced, meanwhile their importance are pointed out. Three kinds of cleaner technologies are put forward-Best Available Technology(BAT), Best Economic Attractive Technology(BEAT), and usually used new technology, combined with some CP casesat home and abroad. several cleaner technologies are compared, and the results show that the implementation of CP can greatly reduce consumption of resource and energy and pollution emission, There are obvious environmental, economic and social benefits. The great potential of CP in industrial pollution control are estimated and demonstrated ultimately.     

Isolation and Characterization of GhLEA3 Gene from Upland Cotton and Its Expression in Response to Low Temperature Stress

[Objective] Based on the analysis of cotton GhLEA3 gene structure and its expression model in chilling stress, we investigated the resistance function of GhLEA3 in response to cold stress. [Method] We cloned GhLEA3 from upland cotton by homologous sequence cloning way. We analyzed the properties of the GhLEA3, and constructed phylogenetic tree by bioinformatics analysis. We constructed the transient expression vector 35S∷GhLEA3-GFP by In-Fusion connection technology and studied the subcellular localization of GhLEA3. The expression of GhLEA3 gene in leaves of TM-1 at three-leaf stage under low temperature stress treatments (4 ℃, 24 h) was performed. Agrobacterium tumefaciens mediated floral dipping method was used to transform the gene with expression vector 35S∷GhLEA3-GFP into Arabidopsis thaliana wild type. Low temperature germination experiment at 4 ℃ was conducted to verify germination ability of the transgenic Arabidopsis thaliana T₃ seed. The transgenic Arabidopsis seedlings were treated at 4 ℃(low temperature), and all the leaves were taken to measure their electrical conductivity. [Result] The coding sequence of GhLEA3 gene is 1 218 bp, which encodes 405 amino acids. GhLEA3 protein includes 4 functional domains of PF02987. Phylogenetic analysis showed that the similarity of amino acid sequences between upland cotton GhLEA3 and Arabidopsis thaliana AtLEA3 was 52.6%. GhLEA3 might be mainly localized in vacuoles and small vesicles. GhLEA3 was up-regulated in leaves after low temperature treatment. The germination rate of transgenic Arabidopsis thaliana of T₃ generation at low temperature was significantly higher than that of wild type, and its electrical conductivity of leaves after low temperature treatment was significantly lower than that of wild type. [Conclusion] GhLEA3 belonged to the member of LEA3 family. Phylogenetic analysis showed that GhLEA3 had the closest relationship with AtLEA3. GhLEA3 was induced by low temperature stress and may play an important role in improving cold resistance.     

黑胫病菌诱导的烟草SSH文库构建及其分析

黑胫病是危害严重的世界性烟草主要病害之一,探究烟草对黑胫病的抗病机制,可以为该病的综合防治提供理论依据。本研究以烟草黑胫病抗性品种革新3号为材料,利用黑胫病0号生理小种诱导其水平抗性,分别在接种后0.5、1、3、6、10和16 d取样,通过抑制差减杂交技术(SSH)构建cDNA文库,获得了960个阳性克隆。利用反向Northern斑点杂交技术对其中240个阳性克隆进行杂交筛选,筛选出57个表达差异明显的基因,序列拼接后获得33条高质量EST,测序及其比对分析表明,革新3号对烟草黑胫病抗性相关基因主要涉及抗病防卫、光合作用、信号传导和能量代谢等方面。进一步基因功能分析显示,病程相关PR1b蛋白、半胱氨酸蛋白、延伸因子1-α、α-微管蛋白、细胞色素P450、精胺合成酶、水通道蛋白、过氧化物酶体膜蛋白、甘氨酸延伸因子等可能参与了烟草与黑胫病菌非亲和互作过程。     

中原牡丹花黄酮定量方法的研究

借助于紫外扫描,通过对氯化铝显色法、硝酸铝—亚硝酸钠显色法和直接测定法3种比色方法与高效液相色谱法测定结果的对比和方法评价的研究,确定了直接测定法(测定波长为350 nm)是一种操作简单、结果较准确的方法。以芦丁为标准品,可用于中原牡丹花黄酮含量的快速测定。     

氮磷钾肥对能源草柳枝稷苗期生长的影响

为了探索柳枝稷在边际土地规模化种植过程中肥料效应方面的基础数据,在日光温室内开展了沙土盆栽柳枝稷苗期氮磷钾肥料效应试验研究。结果表明,氮磷钾肥对沙土盆栽柳枝稷苗期的叶面积、株高、地上生物量、地下生物量、总生物量均具有明显的促进作用,而且,氮磷钾的单因素肥料效应均达到显著水平(P<0.05);柳枝稷苗期总生物量与氮磷钾之间存在着显著的三元二次回归关系,日光温室沙土盆栽条件下,获得柳枝稷苗期最高生物量所需要的适宜氮磷钾浓度分别为:氮(N)94.01mg/kg,磷(P2O5)40.18mg/kg,钾(K₂O)117.96mg/kg。