Solidworks在机床夹具设计中的应用

有别与传统的CAD二维绘图,利用Solidworks绘制三维机床夹具可以非常直观、形象的显示设计结构与结果.本文介绍如何利用Solidworks软件绘制机床夹具三维图形.     

Quantitative real‐time PCR monitoring of Escherichia coli and Clostridium perfringens with oral administration of Lactobacillus plantarum strain Lq80 to weaning piglets

Levels of fecal or intestinal lactobacilli, Escherichia coli and Clostridium perfringens, and the prevalence of clostridial alpha toxin gene and heat‐stable toxin (ST) gene of enterotoxigenic E. coli (ETEC) were monitored in weaned piglets before (day 0) and during (days 7, 14, and 21) the administration of Lactobacillus plantarum strain Lq80. Lactobacilli were enumerated in a culture‐dependent method. The remainders were determined by quantitative real‐time PCR. In this quantitative real‐time PCR method, the detection limit was proved to be as low as 10³ cells/g feces or intestinal contents. Number of lactobacilli increased from day 0 to day 7 (P < 0.05), to day 14 (P < 0.05), and to day 21 (P = 0.07) in the Lq80‐administered group. L. plantarum contributed to as low as 10% of the lactobacillal population in the Lq80‐administered group. The number of E. coli and C. perfringens, and the prevalence of alpha toxin gene in feces or intestinal contents of the Lq80‐administered group decreased, at least in the first week of the postweaning period. Oral administration of L. plantarum strain Lq80 can stimulate the growth of indigenous lactobacilli and decrease ST‐producing ETEC and C. perfringens in the intestine of postweaning piglets.     

植物动力2003对天然草地增产效果的应用研究

应用动物动力２００３试验结果表明，该植物微量元素营养液对天然草地具有明显的增产效果。其平均增产幅度在５００ｍｌ／ｈｍ＾２、１０００ｍｌ／ｈｍ＾２，１５００ｍｌ／ｈｍ＾２剂量下依次为２１．５２％、１８．４１％和２１．５２％，适宜用量为５００ｍｌ／ｈｍ＾２；分１次、２次、３次喷施，分别增产２．４３％、２５．７９％和３５．６０％，以３次喷施效果最佳。     

Excel2003在饲料配合的教学与实践中的应用

探索了应用电脑的常用程序Excel 2003为畜禽拟定低成本饲料配方的方法和步骤,其内容对生产实际和教学有很强的指导性.     

Microsoft Excel 2003在群落生态位参数计算中的应用

[目的]利用Microsoft Excel 2003的基本功能进行数据处理,快速高效地计算出常用的Levins生态位宽度值、Pianka生态位重叠值等参数。[方法]以南京紫金山的麻栎(Quercus acutissima)群落为例,运用Microsoft Excel 2003对该群落中主要优势乔木种类生态位数据进行分析。[结果]麻栎和黄连木的生态位宽度值分别为0.68和0.47。麻栎与其他8个物种的生态位重叠值分别为0.706、0.862、0.648、0.690、0.569、0.839、0.623和0.833,黄连木与其他7个物种的分别为0.485、0.772、0.416、0.498、0.490、0.612和0.324,枫香与其他6个物种的分别为0.588、0.523、0.821、0.653、0.548和0.615,马尾松与其他5个物种的分别为0.653、0.726、0.193、0.549和0.176。[结论]Microsoft Excel 2003具有适用范围广、实用等优点,值得在群落参数的计算和分析中进一步推广和应用     

SWAT模型灵敏度分析模块在黄土高原典型流域的应用

SWAT模型是基于水文过程的、具有很强物理机制的流域分布式水文模型.SWAT2003以SWAT2000为基础,增加了灵敏度分析、自动校准和不确定分析3个全新模块.该文主要介绍SWAT2003模型灵敏度分析模块的原理,并在罗玉沟流域应用与验证.通过灵敏度分析,辨析出影响该流域产流产沙模拟结果精度的主要参数因子:径流曲线数(CN2)和土壤可利用水量(SOL-AWC)对罗玉沟流域模拟产流产沙值的影响最为显著,且对产沙值的影响大于对径流值的影响;而基流α系数(ALPHA-BF)、土壤蒸发补偿系数(ESCO)、坡度因子(SLOPE)和坡长因子(SLSUBBSN)对模拟产沙值的影响也十分显著,但对径流值的影响并不明显.依据上述结论调整参数值,采用连续15年的实测月流量数据对模型进行了校准和验证,结果表明,模型对月流量模拟的相对误差在模型校准期和验证期均小于15%,相关系数R2和Nash-Suttcliffe系数Ens均高于0.8,SWAT2003模型对罗玉沟流域产流的模拟结果良好.因此,灵敏度分析模块的应用极大地提高了模型在黄土丘陵沟壑区的可用性,具有一定的推广意义.     

基于对数螺线方程的秸秆粉碎机锤片设计及应用参数确定

锤片式秸秆粉碎机是目前应用较为广泛的一种秸秆粉碎机型,针对传统锤片工作时受力不均、波动较大进而影响秸秆粉碎效率及锤片的使用寿命等问题,根据对数螺线方程原理,确定了锤片刃线方程及其参数,利用Solidworks建立对数螺线方程曲线刃线锤片的三维实体模型,设计出一种新型的秸秆粉碎机锤片,通过试验表明,等滑切角锤片与普通矩形锤片相比,粉碎玉米秸秆时单位产量的能耗量明显减少,且当滑切角为45°时仅为0.2 kw/h,具有显著的优势,随着玉米秸秆含水率的下降,电能消耗减少;当锤片为45°滑切角,秸秆含水率为20%,锤片末端线速度为70 m/s时,单位产量的能耗量最低。     

Chalcone suppresses lignin biosynthesis in illuminated soybean cells

Lignin and its related metabolites play critical roles in plant growth and development. Thus, lignin biosynthesis has attracted interest as a novel target site of plant growth inhibitors. Chalcone has been shown to not only inhibit lignin biosynthesis in plants, but also to suppress the growth of many annual plant species. In order to know the direct effect of chalcone on plant metabolism, the effects of chalcone on the activities of key enzymes in lignin biosynthesis and on the related metabolites were clarified with a time‐course study by using light‐induced suspension cultures of soybean cells. The fresh weight and packed cell volume of the soybean cells were inhibited after 8 h of chalcone treatment. The activities of phenylalanine ammonia lyase (EC 4.3.1.24) and 4‐coumarate: coenzyme A ligase (4CL; EC 6.2.1.12) were largely inhibited 4 h after the treatment with 0.15 mmol L^?1 chalcone. Unlike these two enzymes, the activity of cinnamyl alcohol dehydrogenase (EC 1.1.1.195) was not inhibited until 16 h after the chalcone treatment. The content of the 4CL substrates and lignin in the soybean cells became relatively lower than the control under the light condition within 4 h and 8 h after the chalcone treatment, respectively. These results suggest that the growth suppression of soybean cells is positively associated with the inhibition of lignin biosynthesis by exogenous chalcone.     

基于PCI柴油机喷油数据采集系统的研究

PCI局部总线具有使用方便和数据传输率高等特点,已成为计算机必备的一种接口.为此,论述了PCI总线接口的组成结构及其优点;介绍了PCI2003数据采集芯片的特点及其在柴油机喷油数据采集系统中的应用.该系统能实现检测数据的接收、显示、保存以及检测报表打印和数据维护等功能.