汽车侧面碰撞中乘员约束系统的可靠性优化

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.     

Effect of ammonia and nitrite on vigour,survival rate,moulting rate of the blue swimming crab <Emphasis Type="Italic">Portunus pelagicus</Emphasis> zoea

The effects of ammonia and nitrite on vigour, survival rate, moulting rate of zoea of blue swimming crab, Portunus pelagicus, were studied. A total of five nitrite-N treatments (26.67, 53.34, 106.68, 213.36, 426.72 mg/l) and a control (no nitrite-N added) were set up for the acute nitrite-N toxicity experiment; a total of five ammonia-N treatments (8.43, 16.86, 33.72, 67.44, 134.88 mg/l) and a control (no ammonia-N added) were set up for the acute ammonia-N toxicity experiment. The results showed that the vigour, survival rate and moulting rate of zoea of the blue swimming crabs exposed to over 53.34 mg/l were significantly different (P < 0.05) from the control group. The zoea LC₅₀ values (mg/l) of nitrite-N were 179.47, 76.56, 66.70, 37.49, 25.01, 25.35, 25.34 mg/l for 24, 36, 48, 60, 72, 84, 96 h, respectively. The vigour, survival rate and moulting rate of zoea of the blue swimming crabs exposed to over 16.86 mg/l were significantly different (P < 0.05) from the control group. The zoea LC₅₀ values (mg/l) of ammonia-N were 51.04, 39.62, 38.72, 24.43, 16.90, 13.42, 11.16 mg/l for 24, 36, 48, 60, 72, 84, 96 h, respectively. The zoeae are highly sensitive to ammonia and nitrite, and the toxicity of ammonia and nitrite on Portunus pelagicus decrease with development of this crab.     

口蹄疫病毒A型竞争ELISA抗体检测试剂盒在流行病学调查中的应用

为评价口蹄疫病毒A型竞争ELISA(cELISA)抗体检测试剂盒在流行病学调查中的应用前景,对2017年从福建省三明市采集的336份黄牛、奶牛、羊和猪血清样品,用A型cELISA抗体检测试剂盒进行抗体检测。结果显示,92份黄牛血清、92份羊血清、92份猪血清、60份奶牛血清的A型抗体阳性率分别为13.04%、11.96%、20.65%、86.67%。从上述4种血清中,各挑选10份血清(阴性、阳性各5份)共40份,采用口蹄疫病毒液相阻断ELISA(LPB-ELISA)抗体检测试剂盒进行验证。结果显示:cELISA检测为阳性的20份血清中,用LPB-ELISA检出阳性19份;cELISA检测为阴性的20份血清中,用LPB-ELISA检出阴性17份;两种方法的κ值为0.8,总符合率为90.00%。结果表明,A型cELISA试剂盒与LPB-ELISA试剂盒的符合率和一致性均较高,可用于口蹄疫流行病学调查和血清学监测。     

Analysis of Genotype,Environment, and Their Interaction Effects on the Phytochemicals and Antioxidant Capacities of Red Rice (Oryza sativa L.)

Fourteen red rice varieties were planted in two locations during summer (Hangzhou) and winter (Hainan) to study the effect of genotype and environment on the phytochemicals and antioxidant capacities of rice grain. B‐type proanthocyanidins in red rice were detected by LC‐MS/MS and quantified by using the vanillin assay. Analysis of variance showed that total phenolic content (TPC), total flavonoid content (TFC) and 2,2′‐azino‐bis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) radical scavenging capacity were mainly affected by environmental factors, which accounted for more than 60% of the total variance. However, total proanthocyanidin content (TPAC) and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging capacity were equally affected by both genotype and environment. The genotype × environment effects were significant for all traits. The pairwise correlations among TPC, TFC, TPAC, ABTS, and DPPH were also significant (r > 0.900, P < 0.001). Principal component analysis identified the genotypes that had higher contents of antioxidants and more stability across environments. This study showed that indirect selection of a simple trait (i.e., TPC) is an effective way to select rice high in antioxidant capacity in breeding programs. This study also suggests that rice should be produced specifically in a certain environment for the end user to minimize the variation in the functional properties and maximize their contents.     

喷播机自动导航控制系统设计及其性能仿真

以嵌入式触摸屏为开发平台,编写了GPS、电子罗盘和超声波传感器Lab VIEW数据采集程序;根据传感器采集的数据,用阶跃信号模拟上位机给喷播机的信号,喷播机以14.4、10.8、7.2、3.6km/h的速度分别在MatLab环境下对该自动导航控制系统进行了模拟测试。经过多次仿真,校正PID参数,结果显示:喷播机运行速度在7.2~10.8km/h,喷播机跟踪上位机信号时间为3~4s。其中,检测信号时间为1~2s,速度最大偏差量在0.36~0.9 7 km/h之间,符合针对草原地形下喷播机作业的要求。     

土地利用变化对土壤水补给来源影响研究

为探究不同植被类型深剖面土壤水补给来源,以黄土区长武塬为研究区,采集两种土地利用方式(农地、18 a苹果园、26 a苹果园)下20 m深土壤剖面,测定土壤水及其稳定性和放射性同位素含量,基于同位素方法对不同土地利用类型下不同深度土壤水来源进行溯源分析。研究表明：(1)苹果园土壤水含量明显低于农地,说明果园耗水强度更大,对深层土壤水影响更为显著。(2)农地、18 a和26 a苹果园下降水偏移量分别为-22‰、-20‰和-6‰,说明降水补给土壤水后受到蒸发作用影响,且农地土壤水比果园受到的蒸发效应更强。(3)该区土壤水补给主要以活塞流为主;对于补给不同深度土壤的可能水源,6 m以下补给水的同位素组成(δ²H=-83.8‰,δ¹⁸O=-12.1‰)较0～6 m (δ²H=-68.8‰,δ¹⁸O=-10.1‰)更为贫化,且6 m以下补给水的氢氧稳定同位素组成与日降水量≥50 mm·d^-1的降水更相似。与农地(δ²H=-70.6‰,δ¹⁸O=-...     

赤霉素和磷肥配合施用对胡麻光合酶活性及其产量形成的影响

为探究赤霉素和磷肥配合施用对胡麻叶片光合酶活性以及籽粒产量的影响,以‘轮选2号’为材料,采用田间二因素裂区试验设计,研究了不同磷肥用量水平(P₀:0 kg·hm^-2 P₂O₅,P₁:67.5 kg·hm^-2 P₂O₅,P₂:135 kg·hm^-2 P₂O₅)和赤霉素(Gibberellin acid, GA₃)喷施浓度(G₀:0 mg L^-1,G₁:15 mg·L^-1,G₂:30 mg·L^-1)对胡麻光合同化酶活性、干物质积累量及籽粒产量的影响。结果表明：施磷和喷施赤霉素均显著提高了胡麻叶片RuBP(Ribulose-1,5-bisphosphate)、PEP(Phospho...     

灌溉渠系流量最优调配的0-1规划模型

本文根据灌溉配水渠系的运行特点,提出在一定轮期和来水流量限制条件下实现下级配水渠最优组合及其配水时间最优排序的一种0-1规划模型,实例运算表明,这种方法可有效减少无效弃水和闸门调节次数,同时对渠道横断面的设计有参考意义。