断根与外源细胞分裂素诱导去叶黑麦草耐牧性的研究

为了研究牧草的持续再生性机制,通过盆栽试验,从黑麦草多次去叶后根系对叶片生长的影响方面,设4个处理：（1）不断根未喷施细胞分裂素,（2）断根未喷施细胞分裂素,（3）不断根喷施细胞分裂素,（4）断根喷施细胞分裂素。结果表明：断根和多次去叶均能降低新生叶片和根系的生物量。多次去叶能引起叶中的赤霉素和脱落酸含量的升高,生长素含量以及玉米素核苷(ZR)含量的降低。多次去叶条件下,喷施外源细胞分裂素能促进叶片中ZR含量及其生物量的增加。相关性分析表明,多次去叶条件下叶中ZR含量与其生物量呈显著性的正相关关系。总之,多次去叶条件下新生叶片中的细胞分裂素含量是影响去叶黑麦草持续再生性的关键因素。     

牵引式红枣残枝粉碎机的设计与试验

红枣残枝粉碎还田是目前亟待解决的问题。为此,设计了一种牵引式红枣残枝粉碎机,通过对辊破碎和动定刀粉碎共同作用实现粉碎效果。对破碎辊轴、粉碎主轴的转速和功率等参数进行了详细阐述,规范了动刀在主轴上的排布方式,选用双螺旋式刀具排布,确保同一时刻有且仅有两个动刀同时工作,有效降低了振动和机组动力损耗,提高了工作效率。运用ANSYS软件对主轴进行了静力学分析及模态分析,得出了应力应变图及粉碎主轴前6阶固有频率和振型图。应力应变图表明:最大应力为8.3326 MPa,最大变形量为0.017419 mm,参考材料特性,主轴强度满足设计要求,故主轴设计合理、安全。模态分析结果表明:最低固有频率为98.286Hz,所对应的临界转速5897 r/min远大于初定主轴转速2000 r/min,因此在工作中主轴转动时不会产生共振现象。样机试验结果表明:粉碎机工作生产率为817.67kg/h,吨功耗为49.06kW/h,噪声为95.3dB,粉碎粒度合格率为86.97%,可以实现连续稳定运作,粉碎粒度符合还田技术要求。     

红枣气体射流冲击干燥收缩特性研究

Chinese jujube originated in China and has a long historical standing. China is the only country which can produce a great amount of Chinese jujube in the world. Modern research showed that the nutrition of Chinese jujube is abundant. Chinese jujube has great medicinal and food value, with high economic value and good prospects for development. Shrinkage characteristics of dates generally refer to volume shrinkage characteristics of whole dates. Large fruit and plump grain appearance of dates is the first choice of consumers to buy elements. The volume of dried jujube points to the consumer’s heart, and is an important indicator of consumers whether to buy. Jujube processing enterprises grade the date in accordance with its size, different grades dates have different value and price. Therefore, drying is the most important steps during the dates processing as it affects directly the quality of the product, and the shrinkage characteristics is the most important quality characteristic of Chinese jujube after drying. However, the traditional natural desiccation and desiccation in the drying room of the red dates has many problems. The conventional drying method for Chinese jujube has some disadvantages of severe shrinkage, long drying time and large energy consumption etc. Therefore, in order to improve the quality of dried Chinese jujube and reduce the shrinkage, it is imperative to replace the traditional drying method with the modern technologies. Air impingement drying technology was applied to dry Chinese jujube. The drying characteristics of shrinkage, moisture effective diffusivity considering shrinkage characteristics and the activation energy of Chinese jujube shrinkage were investigated under different air temperatures (55, 60, 65 and 70℃) and air velocities (6, 9, 12 and 15m/s). The dynamic changes of the regular pattern for the shrinkage characteristic of Chinese jujube in the air impingement drying process were studied, the results showed that the volume relative shrinkage ratio of Chinese jujube appeared to increase and then decrease with the increase of air temperature and air velocity. Considering shrinkage characteristics, the moisture effective diffusivity of Chinese jujube in the air impingement drying process through the Fick’s second law was obtained. The diffusivity appeared to increase and then decrease with the decrease in moisture content in dry basis of Chinese jujube. The Arrhenius equation calculated the shrinkage activation energy of the Chinese jujube was 1281kJ/mol. This research provided technical basis for shrinkage characteristics of Chinese jujube using air impingement drying technology.     

Molecular evolutionary analysis of the duck MYOD gene family and its differential expression pattern in breast muscle development

1. The objective of the research was to investigate the molecular evolutionary relationships between the duck myogenic determination factors (MYOD) gene family members and their roles in muscle development. 2. The four members of the duck MYOD gene family were cloned using RT-PCR, and their relative mRNA expression during duck muscle development was measured using qRT-PCR. 3. The results showed that MyoD and Myf5 clustered together, as did MyoG and MRF4 based on their complete amino acid sequence and the basic helix-loop-helix domain. Results of the evolutionary level analysis were consistent with that of the differential expression patterns during duck breast muscle development. As determined by qRT-PCR, MyoD and Myf5 were highly expressed in 22-day embryos, while MyoG and MRF4 expression was high in 14-day embryos. 4. We conclude that the entire MYOD gene family in the duck originated from a common ancestral gene and evolved after two duplication events. The roles of the MYOD gene family members in duck muscle development are similar to those in mammals.     

天然干酪凝乳工艺影响因素的研究

天然干酪作为一种营养价值极高且极易被消化吸收的绿色食品,在我国已具有了很好的市场发展前景.本文对影响天然干酪产率和品质的关键工艺--凝乳进行了研究.选取凝乳酶添加量、酸度、CaCl2量和凝乳温度为四个影响因素进行正交试验,以乳清中蛋白质、脂肪的残留量为指标,优选凝乳条件.最后综合凝乳时间、乳清中蛋白质和脂肪的残留量这三个指标,得出凝乳的最佳工艺组合:凝乳温度35℃、酸度18°T、CaCl2添加量0.02%、凝乳酶添加量0.006%.     

健康猫被毛真菌菌相

定量检测了４０只临床健康猫的被毛真菌菌相,从３１只猫被毛上共分离出１１个属１７５株真菌,主要为交链孢霉属、芽枝孢霉属、犬小孢子菌和曲霉属等。皮肤病病原菌２个属３个种,包括犬小孢子菌、红色毛癣菌和石膏样毛癣菌。     

添加膨化全脂大豆对高产奶牛血液和乳中尿素氮的影响

选择12头基本条件相近、泌乳50d左右的中国荷斯坦高产奶牛,随机分为四组,采用4×4复合拉丁方试验设计研究高产奶牛日粮中添加膨化全脂大豆对血中尿素氮(BUN)与乳中尿素氮(MUN)动态关系的影响。在基础日粮(TMR)中加入不同水平(0kg、1kg、1.7kg、2.5kg)膨化全脂大豆,每期试验21d,共四期。每期试验第15d、17d、19d、21d取奶样,试验第21d取血样。试验结果表明,对乳中尿素氮,1kg组与对照组差异不显著(P>0.05),1.7kg添加水平与对照组的差异极显著(P<0.01),2.5kg组与对照组的差异显著(P<0.05);对于血液尿素氮2.5kg添加水平显著高于其他三个组(P<0.05)。经BUN与MUN相关分析,MUN值约为BUN的80%。     

基于单片机的沼气发酵装置增温控制系统设计

北方沼气系统全年产气的关键是冬季加热增温问题.为此,以生物质炉为热源,通过对循环水的加热,用单片机控制加热水泵的增温系统,研究设计了系统的整体功能以及硬件和软件.该系统具有一定的智能性,保证了沼气系统在北方冬季时的正常运行,提高了产气量.     

手动仿形雕刻机的设计

木雕制品是对木质材料的艺术处理。这种处理主要通过减除材料将形体挖掘显现出来。随着经济水平的提高,木雕制品制造已成为木工产品加工的重要组成部分。本文介绍一种新型仿形雕刻机的结构和工作原理,该装备动作单元具有空间5自由度,具有对复杂形面复制加工的能力,利用该装备可以实现对木雕制品的仿形加工。     

济南市生态足迹分析

生态足迹是测量确定人类是否生存于生态系统的承载力范围之内的有效方法。作者通过生态足迹模型分析,对1997~2001年生态经济协调发展状态进行定量评估,结果表明济南市生态有较大赤字,并对赤字产生原因和减少赤字的可行性作简要分析。