毒鼠强气相色谱法快速检测与分析

利用气相色谱法对含毒鼠强可疑食物样品进行了测定。结果显示,这种方法快速、准确、灵敏,利于对中毒人畜进行及早地抢救与治疗。     

纤维素酶对棉花秸秆发酵的影响

在人工瘤胃模拟装置的条件下,以棉花秸秆为底物,采用3种纤维素酶(酶1、酶2和酶3)进行体外产气试验. 结果表明:①酶1活性较好,48h平均产气量为17.22ml,与其他处理0.05水平差异显著 , 酶浓度为5g/L时产气量最好,干物质消失率最高;②酶3活性最差,其中酶浓度为10g /L 时产气量最低,干物质消失率也最低;③纤维素酶对产气量、干物质消失率和中性洗涤纤维残余量的影响基本一致.     

丁烯氟虫腈在油菜中残留分析方法的研究

在建立油菜中丁烯氟虫腈残留分析方法的实验中,在添加丁烯氟虫腈浓度为0.05、0.10、0.50μg/ml的油菜样品中分别加入60 ml不同提取溶剂,比较不同提取溶剂对丁烯氟虫腈残留添加回收率的影响。结果表明,乙腈提取效果最好。以乙腈为提取剂提取的丁烯氟虫腈残留液,通过柱层析(中性氧化铝与活性炭的混合物为柱填料)净化,气相色谱测定,得出氟虫腈的最小检测量为2×10-13g。油菜中丁烯氟虫腈(0.05~0.50 mg/kg)的添加回收率为91.12%~93.21%,变异系数是6.01%~13.20%。方法的准确性、灵敏度均达到农药残留分析的要求。     

大米中有机磷和氨基甲酸酯农药残留检测方法研究

应用石英毛细管气相色谱法,利用高灵敏氮磷检测器,用乙腈和丙酮提取样品,建立了一种快速测定大米中有机磷和氨基甲酸酯8种农药残留的方法.结果表明,该方法的最低检出浓度为0.002～0.009 mg/kg.添加量为0.004～O.007mg/kg时,添加回收率为84.3%～120.0%,相对标准偏差为4.1%～11.5%.该方法能同时测定大米中的有机磷和氨基甲酸酯类农药,具有灵敏度高、分离效果好、回收率高、变异系数小、检出限低的特点.     

大豆种子脂肪氧化酶缺失基因控制豆腥味效果的研究

 应用蒸馏提取法、气相色谱和气 -质联机的方法分析了大豆种子脂肪氧化酶缺失体近等位基因系在加工豆制品时所产生的挥发性气味物质。研究结果表明 ,从豆粉和豆浆中都只分离出 2 4种气味成分 ,主要为醛和醇类物质 ;在形成挥发性气味物质和豆腥味物质中 L ox2起主要作用 ,L ox1次之 ,L ox3作用最小 ,但具有降低己醛生成的作用 ;不论缺失 L ox1,还是缺失 L ox2 ,都可极显著地降低挥发性气味物质和豆腥味物质的生成量 ,而缺失 L ox3则会显著增加己醛的生成量 ;缺失基因间存在有显著或极显著的一级和二级负互作 ;不同加工条件对缺失基因的缺失平均效应和互作效应有明显的影响。全缺失体类型具有最低的挥发性物质和豆腥味物质的生成量 ,而缺 L ox3类型具有最高的生成量 ,其余的缺失体类型则介于两者之间 ;用己醛作为衡量脂肪氧化酶在形成豆腥味中的重要性和各种缺失体类型控制豆腥味效果的指标是可行的。因此 ,培育出大豆种子脂肪氧化酶全缺失的品种将有望成为食品加工业的优质原材料     

球墨铸铁曲轴表面气体软氮化强化处理研究

根据气体软氮化特征分析了其机理及组织特点,研究了球墨铸铁曲轴气体软氮化的工艺,氮化后变形、性能变化等。     

西气东输工程水土保持方案实施情况评价

依据西气东输工程水土保持方案采取实地调研和现场勘察相结合的方法,对水土保持预防保护、工程生物防治、土地整治措施的实施以及水土保持资金落实和监理、监测工作情况进行了综合评价。针对存在的水土保持工程质量不高,且与主体工程相比较严重滞后等问题提出了建设性意见。对促进保护环境以及水土保持"三同时"制度的落实具有重要作用。     

实验条件下人工气候舱内的气体质量分析

为规范科研实验条件，更好地为现代畜牧业产业化服务，检验了农业部动物营养学重点开放实验室程控式人工气候舱（简称环控舱）的通风系统的功能，对装载动物的环控舱在正常运转５ｄ以上的气体成分进行分析。测定结果表明舱内的氨气和二氧化碳浓度分别为１１．３～１９．７ｍＬ／ｍ^３和８９０～１ ４００ｍＬ／ｍ^３，均低于家畜卫生标准，但鸡试验舱在上午开舱门清粪前的氨气浓度和猪试验舱的二氧化碳浓度较高，接近了卫生标准的上限值。     

Emission of CO2, CH4 and N2O from lakeshore soils in an Antarctic dry valley

We measured soil profile concentrations and emission of CO₂, CH₄ and N₂O from soils along a lakeshore in Garwood Valley, Antarctica, to assess the extent and biogeochemical significance of biogenic gas emission to C and N cycling processes. Simultaneous emission of all three gases from the same site indicated that aerobic and anaerobic processes occurred in different layers or different parts of each soil profile. The day and location of high gas concentrations in the soil profile corresponded to those having high gas emission, but the pattern of concentration with depth in the soil profile was not consistent across sites. That the highest gas concentrations were not always in the deepest soil layer suggests either limited production or gas diffusion in the deeper layers. Emission of CO₂ was as high as 47 μmol m⁻² min⁻¹ and was strongly related to soil temperature. Soil respiration differed significantly according to location on the lakeshore, suggesting that factors other than environmental variables, such as the amount and availability of O₂ and nutrients, play an important role in C mineralization processes in these soils. High surface emission (maximum: 15 μmol m⁻² min⁻¹) and profile gas concentration (maximum: 5780 μL L⁻¹) of CH₄ were at levels comparable to those in resource-rich temperate ecosystems, indicating an active indigenous population of methanogenic organisms. Emission of N₂O was low and highly variable, but the presence of this gas and NO₃ in some of the soils suggest that denitrification and nitrification occur there. No significant relationships between N₂O emission and environmental variables were found. It appears that considerable C and N turnover occurs in the lakeshore soils, and accurate accounting will require measurements of aerobic and anaerobic mineralization. The production and emission of biogenic gases confirm the importance of these soils as hotspots of biological activity in the dry valleys and probable reservoirs of biological diversity.     

Hydrogen consumption rate in a soil as an indication of compaction and gas-diffusion status

Summary H₂ consumption rates were significantly correlated with penetrometer measurements of soil samples at different compaction levels. By measuring the ratio of the H₂ consumption of an undisturbed soil sample to that of a sieved soil, it is possible to obtain, in a rapid and simple way, an indication of the gas-diffusion status of the soil.