持续亚低温对甜瓜幼苗生理生化指标的影响

以厚皮型甜瓜（久红瑞、2-64）、薄皮型甜瓜（久青蜜、002）和厚薄皮中间型甜瓜（久脆蜜、久仙）3种类型的6个甜瓜(Cucumismelon L.)品种为材料,研究了夜间持续亚低温（8～15 ℃）、白天正常温度条件对不同生态型甜瓜品种苗期生理生化指标的影响。结果表明,在持续亚低温处理期间,可溶性蛋白含量的变化率呈先增大后减小的变化规律;各品种可溶性蛋白含量只有久青蜜先减少后增加,其余品种均一直减小。电导率的变化是久青蜜和2-64电导率的值减小,其余均增加。久青蜜、久红瑞和久仙脯氨酸的含量先减小后增加,其余均一直减小。久青蜜、002和久仙脯氨酸含量的变化率先减小再增加,久红瑞和2-64一直减小,久脆蜜先增加再减小。综合研究来看,对持续亚温有较好抗性的品种为薄皮型的久青蜜和厚皮型的久红瑞,它们可以作为生产上的耐低温品种。     

农牧区农机安全管理的思考

《中华人民共和国道路交通安全法》、《农机化促进法》、《农牧区农业机械管理条例》的相继出台,这些法律、法规的颁布和实施给农机安全管理事业带来了新的发展机遇和挑战。农化安全生产管理是推进社会主义新农村建设的重要内容;推进社会主义新农村建设必须重视农机安全生产,强化农机安全管理;加强农机监理队伍建设,进一步提高依法安全管理水平;强化农机安全宣传教育,提高广大农机驾驶操作人员的法制观念和操作技术水平。     

原竹骨架喷涂复合材料多功能组合构件力学性能试验研究

为研究原竹骨架喷涂复合材料组合构件的力学性能,该文通过立柱轴压性能和抗弯性能足尺试验,研究其传力过程、承载能力、破坏模式及复合材料对原竹骨架的增强作用。结果表明:组合构件立柱轴压试验的破坏模式为整体失稳破坏;在有限元参数分析中,立柱数目少于6根时,立柱数目越多,平均每根立柱的轴压承载力越大,但立柱数目超过6根时,平均每根立柱的极限承载力随立柱数目的增多反而有降低的风险;立柱间距在200~500 mm范围内,间距越大,其立柱平均承载力越高;对多根立柱统一均匀加载时,构件会发生整体失稳破坏,而对中间立柱单根加载时,其顶部出现局部压溃现象。抗弯性能试验的破坏模式为纵向原竹与复合材料产生滑移,构件在集中荷载处发生弯折破坏。复合材料对构件立柱提供了较好的约束作用,使其轴压承载力提高3.7倍,但与立柱达到抗压强度破坏时的极限承载能力相比低16.7%;当达到组合构件的弯曲容许挠度和峰值挠度时,构件所承担荷载分别约为原竹骨架构件的7倍与4倍,说明复合材料对原竹骨架的增强作用显著。研究成果可为喷涂复合材料-原竹骨架组合结构体系的工程应用提供参考。     

云南省边境地区口蹄疫抗体检测

应用口蹄疫O、A、Asia-1型cELISA抗体检测试剂盒和口蹄疫非结构蛋白抗体单抗阻断ELISA试剂盒,对采集自云南省10个边境县的牛和猪血清进行检测。检测结果显示,牛口蹄疫O、A、Asia-1型抗体阳性率分别在9.23%~37.75%、3.00%~23.57%、9.75%~48.67%之间,阳性率偏低,并且地区间差异较大。非结构蛋白抗体阳性率在14.16%~51.00%之间,其中勐海为51.00%、芒市为48.96%,动物带毒风险较大。境内牛与境外入境牛口蹄疫O、A、Asia-1型抗体阳性率基本相当,非结构蛋白抗体阳性率略高于境内牛。由于入境牛免疫率较低,须加大对入境牛的监控。黄牛和水牛口蹄疫O、A、Asia-1型抗体阳性率基本一致,但黄牛非结构蛋白抗体阳性率为36.47%,水牛为26.86%,黄牛阳性率显著高于水牛,这可能是因为云南省边境地区的黄牛主要来自印度、孟加拉国,经缅甸进入我国。猪口蹄疫血清抗体阳性率较低,除芒市O型口蹄疫抗体阳性率达到81.00%外,其余均在0~6.00%之间,这可能与云南省近年来大量免疫合成肽疫苗有关。建议加强云南省边境地区的口蹄疫防控工作,提高口蹄疫免疫密度和抗体水平,严控边境地区口蹄疫易感动物的无序流动。     

非线性市场需求下考虑利益关系约束的农产品供应链参与主体决策研究

基于二级农产品供应链,在非线性市场需求环境中,研究强、弱两种利益关系约束下农产品供应链参与主体的最优决策。通过建立利润函数对比最优决策,并利用算例验证结论和探讨利润变化趋势,以提出合理的政策建议。研究表明:在收益共享契约下,强利益约束能使各参与主体获取超额利润,且参与主体的最优决策更贴近保障农产品供需稳定方向;收益共享系数在可行取值域内的增大,对农产品生产商更有利。     

制动工况下液力偶合器涡轮轴向漩涡流场试验分析

轴向漩涡流动是研究液力偶合器能量损耗的重要基础。该文基于粒子图像测速技术采集制动工况下液力偶合器轴向漩涡流场图像,通过图像处理技术识别并提取液力偶合器外壁面上特殊几何结构所呈现的光学特征,完成流动图像动态标定。利用霍夫变化直线检测算法识别泵轮轴向流场流速方向,通过图像互相关算法并采用查询窗口偏移技术提取涡轮轴向漩涡流场结构,应用误矢量识别算法检测错误流速矢量并予以剔除,获得优化的流动图谱。研究结果表明:泵轮轴向流场中液流是一种复合加速运动;涡轮轴向流场中液流是一种多尺度漩涡流动,主流区域上流速值为0.2~0.4 m/s,叶片与壁面组成的角隅区域上形成小尺度涡旋,角隅区域上流速值为0.6~1.1 m/s。上侧叶片与泵轮、涡轮交界面处的角隅区域上存在与主流循环流动方向相同的小尺度涡旋,涡量数值为?8 s?1,此处涡旋将促进液力能量的传递与转换,其他3个角隅区域上的涡旋方向与此相反,涡量数值分别为13、15和20 s?1,由于该局部区域小尺度涡与主循环涡的相互混合作用,引起流动迟缓,造成能量损耗。试验研究结果将为液力偶合器轴向漩涡流动现象提供有价值的参考依据。     

Simulation of the effects of genotype and N availability on rice growth and yield response to an elevated atmospheric CO2 concentration

The objective of this study was to identify physiological processes that result in genotypic and N fertilization effects on rice yield response to elevated atmospheric CO₂ concentrations ([CO₂]). This study conducted growth and yield simulations for 9 rice genotypes grown at 4 climatically different sites in Asia, assuming the current atmospheric [CO₂] (360 ppm) and elevated [CO₂] (700 ppm) using 5 levels of N fertilizer (4, 8, 12, 16, 20 g m⁻² N fertilizer). A rice growth model that was developed and already validated for 9 different genotypes grown under 7 sites in Asia was used for the simulation, integrating additional components into the model to explain the direct effect of [CO₂] on several physiological processes. The model predicted that the relative yield response to elevated [CO₂] (RY, the ratio of yield under 700 ppm [CO₂] to that under 360 ppm [CO₂]) increased with increasing N fertilizer, ranging from 1.12 at 4 g m⁻² N fertilizer to 1.22 at 20 g m⁻² N fertilizer, averaged overall genotypes and locations. The model also predicted a large genotypic variation in RY at the 20 g N treatment, ranging from 1.08 for ‘WAB450-I-B-P-38-HB’ to 1.41 for ‘Takanari’ averaged overall locations. Combining all genotypes grown at the 5N fertilization conditions, a close 1:1 relationship was predicted between RY and the relative [CO₂] response in spikelet number for crops with a small number of spikelets (less than 30,000 m⁻²) under the current atmospheric [CO₂] (n = 18, r = 0.89^***). In contrast, crops with a large number of spikelets under the current atmospheric [CO₂] showed a significantly larger RY than the relative [CO₂] response for spikelet number per unit area. The model predicted that crops with a larger number of spikelets under the current atmospheric [CO₂] derived great benefit from elevated [CO₂] by directly allocating increased carbohydrate to their large, vacant sink, whereas crops with a smaller number of spikelets primarily required an increased spikelet number to use the increased carbohydrate to fill grains. The simulation analyses suggested that rice with a larger sink capacity relative to source availability under the current atmospheric [CO₂] showed a larger yield response to elevated [CO₂], irrespective of whether genotype or N availability was the major factor for the large sink capacity under the current [CO₂]. The model predicted that the RY response to nitrogen was brought about through the N effects on spikelet number and non-structural carbohydrate accumulation. The genotypic variation in RY was related to differences in spikelet differentiation efficiency per unit plant N content. Further model validation about the effects of [CO₂] on growth processes is required to confirm these findings considering data from experimental studies.     

Splenic lipidosis in intensively cultured perch,Perca fluviatilis L.

Macroscopically visible lipid deposition varying in size from pinpoint to 8‐mm diameter was found in spleens of a population of intensively farmed perch, Perca fluviatilis L. over a 24‐month rearing period. Large agglomerates of adipocytes distinguishable from surrounding normal tissue occurred in all individuals with spleen lipidosis. Several affected fish presented total dystrophy of large clusters of hepatocytes. Prevalence of lipidosis was 5.0% at 12 months and 16.6% at 24 months. There was no significant difference between fatty acid profiles of liver or perivisceral fat of perch with and without lipidosis except for linoleic, myristic, γ‐linoleic, cis‐eicosatrienic, palmitooleic acid. Body weight and hepatosomatic, perivisceral fat and splenosomatic indices were not associated with lipidosis. There was no significant effect of lipidosis on mortality or growth.     

持续亚低温对甜瓜幼苗生理生化指标的影响

以厚皮型甜瓜(久红瑞、2-64)、薄皮型甜瓜(久青蜜、002)和厚薄皮中间型甜瓜(久脆蜜、久仙)3种类型的6个甜瓜(Cucumismelon L.)品种为材料,研究了夜间持续亚低温(8～15℃)、白天正常温度条件对不同生态型甜瓜品种苗期生理生化指标的影响.结果表明,在持续亚低温处理期间,可溶性蛋白含量的变化率呈先增大后减小的变化规律;各品种可溶性蛋白含量只有久青蜜先减少后增加,其余品种均一直减小.电导率的变化是久青蜜和2-64电导率的值减小,其余均增加.久青蜜、久红瑞和久仙脯氨酸的含量先减小后增加,其余均一直减小.久青蜜、002和久仙脯氨酸含量的变化率先减小再增加,久红瑞和2-64一直减小,久脆蜜先增加再减小.综合研究来看,对持续亚温有较好抗性的品种为薄皮型的久青蜜和厚皮型的久红瑞.它们可以作为生产上的耐低温品种.     

科尔沁沙地西部地区防护林体系营造技术的研究

本项研究针对科尔沁沙地西部风沙危害严重的玉田皋、那么罕地区生态现状,依据本地区坨－甸－土召镶嵌分布的地貌景观及不同立地条件,以农田、草场为重点保护对象,设计并建成由人工固沙植被、防风阻沙林带、公路防护林带、农田－草牧场防护林网、果园防护林等５种类型组成的沙地综合防护林体系。根据不同立地类型分别采取开沟地、穿透碱层和挖沟排水整地造林技术,造林成活率达８５－９４％。７年生农田防护林带背风面１０－１５Ｈ范围内,平均可以减弱风速４３－４７％;８年生草牧场防护林带２０Ｈ范围内平均降低风速３１－４３％,林网内蒸发量减少１５－２２％。