汽车侧面碰撞中乘员约束系统的可靠性优化     

肖志  叶映台  李伟平  杨济匡 《湖南农业大学学报(自然科学版)》2011,38(9):39-43

在汽车侧面碰撞中，约束系统对降低乘员的伤害起到非常重要的作用.本文采用MADYMO仿真分析软件，建立某车型侧面碰撞的约束系统仿真模型；考虑了髋部推动块的压溃力、气囊起爆时间、气体质量流量和气袋排气孔面积对乘员损伤的影响，建立了乘员损伤指标的响应面模型；基于蒙特卡罗随机模拟，进行了侧面碰撞乘员约束系统的可靠性优化.结果表明，优化后的约束系统设计方案满足可靠性目标要求.  相似文献   

二倍体栽培棉种草棉和亚洲棉的核型比较研究   总被引：5，自引：0，他引：5  

宋平  季道藩 《作物学报》1991,17(2):102-106

以二倍体栽培棉种草棉(Gossypium herbaceumL.)3个品种和亚洲棉(G.arboreum L.)6个品种,以及1个亚洲棉与草棉种间杂种 F_1为材料,进行核型分析。结果表明,草棉和亚洲棉在核型上基本相似,其主要差异是草棉具有2对 st 染色体,而亚洲棉中没有;虽然2个棉种的核型类别都属于2A 型,但草棉的核型比亚洲棉更对称,属于较原始的类型。来  相似文献   

不同品系杜洛克后代商品猪胴体性状的比较分析     

陈鑫  田琛  姬应来  王建朋  孙晓梅  孙义姗  高若男  和军飞  李清春  卢世豪  黄涛 《猪业科学》2021,38(4):110-112

为研究不同品系杜洛克作为终端父本对其后代商品猪胴体性状的影响,选取214和108头分别由美系和加系杜洛克公猪配种、出生时间相近(±2 d)和体重相近(35±5 kg)的后代三元商品猪进行育肥饲养,结束饲养后开展屠宰试验,测定背膘厚度、眼肌厚度、瘦肉率和肋骨数。结果显示:加系杜洛克商品后代的背膘厚度、眼肌厚度显著(P<0.05)高于美系杜洛克后代商品猪;加系杜洛克后代商品猪的瘦肉率、肋骨数显著(P<0.05)低于美系杜洛克。同一品系不同性别间背膘厚度、眼肌厚度、瘦肉率均不显著(P>0.05),加系商品公猪肋骨数极显著低于母猪肋骨数(P<0.01)。结论:美系杜洛克后代商品猪的胴体性状优于加系杜洛克后代商品猪。  相似文献   

Effects of dietary supplementation of nucleotides from late gestation to lactation on the performance and oxidative stress status of sows and their offspring     

Chengquan Tan  Yongcheng Ji  Xichen Zhao  Zhongquan Xin  Jiaying Li  Shuangbo Huang  Zhiying Cui  Lijun Wen  Caihua Liu  Sung Woo Kim  Jinping Deng  Yulong Yin 《动物营养（英文）》2021,7(1):111

Increased metabolic burdens in breeding sows, which are induced by elevated systemic oxidative stress, could increase the need for nucleotides to repair lymphocyte DNA damage; however, de novo synthesis of nucleotides may be insufficient to cover this increased need. This study investigated the effects of dietary nucleotides on milk composition, oxidative stress status, and the reproductive and lactational performance of sows. Forty multiparous sows were assigned to 2 dietary treatments (Control group, and 1 g/kg Nucleotides group) based on a randomized complete block design using their BW at 85 d of gestation as a block. Sows from 2 groups were fed a restricted diet during gestation and ad libitum during lactation. The experiment lasted from 85 d of gestation to 21 d of lactation. The reproductive performance of sows and the growth performance of suckling piglets were measured. Oxidative stress parameters and milk components were also analysed. Data were analyzed using contrasts in the MIXED procedure of SAS. Sows in the Nucleotides group consumed more feed during the first week (P < 0.01) and from 1 to 21 d (P < 0.05) of lactation than those in Control group. Correspondingly, the litter weight gain of piglets showed a tendency to increase from cross-fostering to 9 d (P = 0.09) and from cross-fostering to 20 d (P = 0.10) in the Nucleotides group relative to the Control group. Additionally, the Nucleotides group was higher (P < 0.01) than the Control group in the concentrations of uridine 5''monophosphate, guanosine 5''monophosphate, inosine 5''monophosphate, adenosine 5''monophosphate and total nucleotides in milk. Furthermore, the Nucleotides group was higher (P < 0.01) than the Control group in the serum levels of total antioxidant capacity (P < 0.01) for sows at 109 d of gestation and glutathione peroxidase for weaning piglets, but lower at the levels of thiobarbituric acid-reactive substances (P < 0.05) in serum of weaning piglets. This study indicated that maternal dietary nucleotides could promote piglet growth, probably due to the higher lactational feed intake and higher concentration of nucleotides in the milk of sows, and lower oxidative stress for both sows and piglets.  相似文献   

离心除精浆对提高冷冻精液品质的作用     

姬云涛屈长青  曹斌云 《中国农学通报》2005,21(11):9-12,32

采用离心洗涤法去除精浆后,对精液进行冷冻处理。发现:1、除精浆精子冻后的活率、Ⅰ类顶体率和精子畸形率与未除精浆组存在显著差异(P<0．05);2、除精浆使稀释后精液精浆中GOT和LDH活性明显升高(P<0．05)。从平衡后到解冻后各组GOT和LDH活性都呈上升趋势。但除精浆试验组比未除精浆试验组上升缓慢;3、除精浆试验组精子的穿卵率、卵内平均精子数都显著高于未除精浆试验组(P<0．05);4除精浆离心洗涤液用生理盐水和脱脂乳-卵柠液．两者之间无显著差异(P>0．05)。  相似文献   

国内甘薯机械移栽技术发展动态   总被引：4，自引：0，他引：4  

胡良龙  计福来  王冰  凌小燕  胡志超  于向涛 《中国农机化学报》2015,(3):289-291,317

甘薯机械化移栽技术发展严重滞后已成为制约甘薯现代化生产的主要技术瓶颈。在对国内外甘薯机械移栽技术发展现状阐述、分析基础上,初步提出国内甘薯移栽机械的技术发展方向:农机农艺融合提高移栽效率、裸苗移栽优先、重视钵苗移栽、多种栽插形式并存、先栽后浇分段作业等。  相似文献   

边界滑移对螺旋槽上游泵送机械密封性能的影响     

陈汇龙  徐成  胡吉  刘志斌  赵斌娟  李述林 《排灌机械》2015,(1)

为了研究边界滑移对上游泵送机械密封性能的影响,建立液膜三维几何模型和计算模型,基于 Navier 线性滑移模型对液膜壁面边界条件进行修正,采用商用软件 Fluent 的 SIMPLEC 算法及层流模型求解三维 Navier －Stokes 方程,并分析相对滑移量对液膜静压分布、开启力、摩擦扭矩、泄漏量的影响规律。结果表明：相对于边界滑移发生的位置,滑移速度的大小对密封性能的影响更大;当相对滑移量较小时,存在边界滑移与无滑移的模拟结果无明显区别,能很好地解释宏观无滑移边界假设的应用,当相对滑移量较大时液膜动压效应随滑移的增加而减弱,开启力、摩擦扭矩、泄漏量都随边界滑移的增加而减小;相对于开启力的降低,边界滑移的减阻和降低泄漏的效果更为明显;当开启力较小,应避免边界滑移发生;当开启力足够大时,加工成超疏水表面形成边界滑移,可极大地减少摩擦扭矩,降低能耗。  相似文献   

A peptide of foot-and-mouth disease virus serotype Asia1 generating a neutralizing antibody response, and an immunostimulatory peptide   总被引：2，自引：0，他引：2  

Wang JL  Liu MQ  Han J  Chen WZ  Cong W  Cheng G  Gao YH  Lu YG  Chen JL  Zuo XP  Yan WY  Zheng ZX 《Veterinary microbiology》2007,125(3-4):224-231

The epitopes of the capsid of foot-and-mouth disease virus (FMDV) play important roles in the construction of highly immunogenic subunit vaccines. However few epitopes have been found for FMDV serotype Asia1. In this study we screened for epitopes of the VP1 and VP2 proteins of FMDV serotype Asia1 isolate, YNBS/58. Fragments consisting of amino acids 133-163 of VP1 and amino acids 1-33 of VP2 contained epitopes, and both induced lymphoproliferation in guinea pigs. Only the VP1 fragment induced neutralizing antibodies but the VP2 peptide dramatically increased the neutralizing antibody response induced by the VP1 peptide.  相似文献   

The organic acid profiles in the feces of pigs at Brachyspira hyodysenteriae- or B. pilosicoli-positive farms     

Piao SJ  Tsukahara T  Itoh M  Shiga A  Adachi Y  Ushida K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(4):425-428

We observed a significant difference in the organic acid profile of diarrheal feces between pigs infected with and free from pathogenic spirochetes. Diarrhea and loose feces were collected from growing pigs, held at 15 different commercial farms. A total of 106 samples were measured for organic acid concentration by HPLC and were checked for the presence of B. hyodysenteriae and B. pilosicoli by PCR. B. hyodysenteriae was detected in 3 samples collected from one farm. B. pilosicoli was detected in 5 samples collected from another farm. Lower concentrations of iso-butyrate and iso-valerate were likely associated with development of pathogenic spirochete infection.  相似文献   

犬瘟热、犬细小病毒胶体金二联检测卡研制     

余春明  郑雪莹  范君文  史记  李华斌  郑金来  邓柏林 《中国动物检疫》2023,40(1):128-133

本研究通过细胞融合、间接ELISA方法筛选出4株可稳定分泌犬瘟热病毒(canine distemper virus,CDV)和犬细小病毒(canine parvovirus,CPV)单克隆抗体的杂交瘤细胞株,以此为基础研制了一种可同时检测CDV和CPV的胶体金二联检测卡,并对其特异性、灵敏度及准确性进行了测试。结果显示：4株杂交瘤细胞可稳定传代,分泌的单克隆抗体纯度高,效价均在1:320以上。制备的胶体金二联检测卡特异性强,只与CDV和CPV产生特异性条带,而不与其他犬类病毒反应;灵敏度高,最低检测限可达到10²拷贝/μL;准确性好,与荧光定量PCR结果的符合率高于88.0%,与市面上单一病毒检测卡的符合率高于97.2%。结果表明,本研究制备的CDV、CPV胶体金二联检测卡特异性强、灵敏度高、准确性好,兼具操作简便、肉眼可判读、结果易保存和无需特殊仪器设备等优势,可用于两种疾病的临床快速诊断和大规模检测工作。  相似文献