肉桂油/海藻酸钠薄膜物理特性和抗菌性能分析

为了研究开发新型可降解抗菌包装材料,该文以添加不同体积肉桂油到海藻酸钠膜液中制成的肉桂油/海藻酸钠抗菌薄膜为研究对象,比较分析肉桂油添加量对肉桂油/海藻酸钠薄膜厚度、透光率、色泽和水蒸气透过率等物理特性的影响,同时,考察其对薄膜的抗菌性能的影响。膜液中肉桂油体积分数在0～1.0%时,薄膜厚度无明显变化,体积分数为1.2%时,薄膜厚度显著增加。随着肉桂油体积分数的增加,薄膜的透光率显著降低,薄膜水蒸气透过系数增大。肉桂油对薄膜色泽影响显著,随着肉桂油添加量的增加,薄膜色泽值a和b呈显著增加趋势。膜液中肉桂油体积分数为0.8%时,薄膜抗菌能力显著增强。研究结果表明,当膜液中肉桂油体积分数为0.8%时,薄膜具有较好的抗菌效果和物理性能。该研究可为肉桂油/海藻酸钠可降解抗菌薄膜生产工艺参数的进一步优化提供参考。     

夹指链式残膜回收装置的设计及试验

针对国内现有残膜回收设备残膜回收率低、残膜易缠绕收膜部件、膜杂分离困难、脱膜效果差和残膜含杂量高导致回收的残膜不能再利用等问题,设计了一种夹指链式残膜回收装置,主要由收膜装置、脱膜装置和传动系统等部分构成,收膜装置上设有夹指链和切膜圆盘,切膜圆盘将地表残膜切成带状,夹指链上的夹指将带状残膜依次从地面捡起。通过对主要工作部件的设计,确定了其结构尺寸参数,并对该装置的收膜和脱膜运动进行了分析与讨论,确定了其工作参数。田间试验表明,该回收装置在作业速度5.5 km/h、下夹指链输送倾角40°、机组前进速度与收膜链线速度之比2时,残膜回收率达90.5%,未出现残膜缠绕上链轮现象,回收的残膜含杂量少,便于后续处理和再利用,能满足残膜回收技术的要求。设计研究成果可用于研制新型残膜回收机。     

基于Meta-analysis的中国马铃薯地膜覆盖产量效应分析

为了定量综合分析中国近30 a地膜覆盖对马铃薯的增产效果,该研究综合已发表的田间试验研究数据,应用Meta-analysis方法定量分析使用地膜后马铃薯产量的增产率或减产率,并探讨其时空分异特征及其影响因素。通过文献检索,共获得84篇有关地膜覆盖马铃薯生产试验文献。经严格筛选,共从42篇文献中获得52组数据,分布于中国14个省(市、区),涵盖西北、西南和东南3个主要区域。主体数据经Meta分析表明:地膜覆盖在西北地区增产效应最显著,相对增产率为35.6%;其次是东南和西南地区,相对增产率分别为20%和12%;从全国时间序列看,1990年以后地膜相对增产率较高,但2010年后地膜增产效果有降低趋势;白色地膜与黑色地膜、垄作和平作对地膜增产效应影响不显著;在年均降水量500 mm和年均温10℃的区域地膜增产效应最明显,地膜相对增产率分别为40.5%和37.6%。进一步分析表明,2010年后地膜覆盖效果在年均降水量500 mm且年均温10℃的地区和年均降水量500 mm且年均温10℃的地区均呈现降低趋势,说明全球气候变暖可能对地膜增产产生负面影响,或随着使用年限增加地膜开始表现出对产量的负面效应。该研究可为地膜覆盖技术应用提供参考。     

氧化节杆菌生物降解苯并芘

A pot experiment was conducted with multi-metal (Pb, Cd, Cu, and Zn) contaminated acidic soil to investigate changes in available metal burden resulting from the application of industrial wastes (fly ash and steel slag). The efficiency of amendments-induced metal stabilization was evaluated by diffusive gradients in thin films (DGT), sequential extraction, and plant uptake. The stability of remediation was assessed by an acidification test and by chemical equilibrium modeling. Addition of fly ash (20 g kg-1 ) and steel slag (3 g kg-1 ) resulted in similar increase in soil pH. Both amendments significantly decreased the concentrations of metals measured with DGT (C DGT) and the metal uptake by Oryza sativa L. Significant correlations were found between C DGT and the concentration of a combination of metal fractions (exchangeable, bound to carbonates, and bound to Fe/Mn oxides), unraveling the labile species that participate in the flux of metal resupply. The capability of metal resupply, as reflected by the R (ratio of C DGT to pore water metal concentration) values, significantly decreased in the amended soils. The C DGT correlated well with the plant uptake, suggesting that DGT is a good indicator for bioavailability. Acidification raised the extractable metal concentration in amended soil but the concentration did not return to the pre-amendment level. Equilibrium modeling indicated that the soil amendments induced the precipitation of several Fe, Al and Ca minerals, which may play a positive role in metal stabilization. Chemical stabilization with alkaline amendments could be an effective and stable soil remediation strategy for attenuating metal bioavailability and reducing plant metal uptake.     

Efficacy of essential oils combination on performance,ileal bacterial counts,intestinal histology and immunocompetence of laying hens fed alternative lipid sources

This study was carried out to assess the effects of a blend of herbal essential oils (namely Thymus vulgaris, Mentha piperita, Rosmarinus offisinalis and Anethum graveolens) and different dietary lipid sources on the performance, ileal bacterial enumeration, intestinal histological alterations and immune responses in laying hens. For this purpose, a total of 150 laying hens were randomly allocated to six experimental treatments with five replicates of five birds each. Dietary treatments consisted of three levels of a mixture of essential oils (0, 100 and 200 mg/kg) and two sources of lipid (soybean oil and fish oil containing different ratios of n‐6 to n‐3 fatty acids) fed to the animals during an 80‐days feeding trial. Findings indicated that dietary administration of fish oil not only increased significantly the spleen relative weight (p < 0.01) and the antibody titre against Newcastle virus (p < 0.05) but also led to reductions in liver relative weight (p < 0.05) and feed conversion ratio (p < 0.05). Moreover, the mixture of herbal essential oils brought about declines in hepatic relative weight, heterophile to lymphocyte ratio (p < 0.05) and intestinal pathogen populations (p < 0.01). Mention must also be made of the improvements it made in spleen weight (p < 0.01), antibody titres against SRBC (p < 0.01) and Newcastle virus (p < 0.05), villus height to crypt depth ratio (p < 0.01), goblet cell numbers (p < 0.05), lamina propria lymphatic follicle diameters (p < 0.01) and feed conversion ratio (p = 0.06). It may be claimed that the enhancements observed in the performance of laying hens fed fish oil and 200 mg/kg of the blend of essential oils could have potentially been associated with improved intestinal health indices as well as cellular and humoral immune responses.     

吊篮式裸根棉苗膜上移栽机的设计

针对新疆地区棉花种植采用滴灌加铺膜的种植模式,设计了一种吊篮式裸根棉苗膜上移栽机。该机的覆土滚筒可将大小不等的土块分离开,在膜面上形成移栽用碎土道,碎土道上的土通过滑板上帆布拨片的拨动进入吊篮内部,避免了裸根棉苗在移栽时的倾倒,保证了移栽质量。试验表明,在移栽单体上有4个吊篮的情况下,作业速度为1.2~1.65 km/h时,栽植质量比较稳定,栽植率大于95%,栽植深度均匀,覆土厚度稳定。     

黑色素自组装薄膜制备的研究

采用自组装技术,在碱性溶液中制备黑色素自组装薄膜。利用扫描电镜、红外光谱、光电子能谱和X射线衍射仪对其进行表征。结果表明,黑色素溶液在带有负电荷的基底(硅片)上,通过自组装技术组装,得到均匀和形貌一致的黑色素薄膜。由红外光谱和光电子能谱可知,黑色素成分通过N-O-Si形式与基底结合。X-射线衍射结果显示,组装在硅片上的自组装薄膜在2个方向上都是有序的结构。这对理解黑色素薄膜的微观结构是非常有用的一个研究。     

Consumers’ acceptance of optimized gluten-free sorghum-based cakes and their drivers of liking and disliking

Sensory analysis is indispensable in order to promote the project of developing sorghum-based products and, therefore, work on sensory profiles of these products and consumer acceptance is needed to help them succeed. Thus, this study investigated the acceptance of 5 optimized gluten-free sorghum-based and a Reference (with gluten) cakes (prepared from cake premixes), considering their drivers of liking and disliking and their purchase intention. Chocolate and orange flavored gluten-free cakes were prepared based on the numerical optimizations of the formulations (technological, nutritional, functional, technological and nutritional, and technological and functional optimizations). Three sensory evaluation techniques were applied to cakes: acceptance testing, purchase intention and Check-all-that-apply. There was an improvement in the sensory properties of the gluten-free samples in which the nutritional or functional characteristics were optimized together with the technological characteristics, resulting in higher acceptances. It was confirmed that sensory studies are indispensable to confront the challenge of developing sorghum-based foods with sensory characteristics desired by consumers. Therefore, it is concluded that it was possible to offer a gluten-free cake premix that presents good sensory quality, having the potential to be offered as a novelty by the food industry, given that most consumers stated that they did not know sorghum.     

水肥液膜配合对玉米生物学特性及水分利用效率的影响

玉米节水节肥高产研究对保障粮食安全具有重要现实意义,本研究供试玉米品种为‘郑单958’,采用旱棚盆栽试验,研究液膜覆盖、灌水与施肥对夏玉米生物学特性、产量及水分利用效率的影响。结果表明:在欠水条件(200mm)与贫水条件(300mm)下,液膜覆盖促进夏玉米生长发育的效果显著,L3水平(液膜45kg/hm~2)玉米株高和叶面积指数比L1水平(无液膜)分别增加了33.88%,36.07%,产量增加53.77%,20.76%;平水(400mm)、丰水条件(500mm)下,夏玉米株高、茎粗与叶面积指数在全生育期均高于欠水、贫水处理,并且产量显著高于欠水、贫水处理,水、肥、液膜对夏玉米生物学特性及产量的影响为:W(水分)F(施肥)L(液膜);以C11(W3F3L1)处理玉米茎粗、叶面积指数、产量均为最高,分别为20.2mm,5.86,148.83g/pot。综上,在缺水条件下,喷施液态膜可提高玉米水分利用效率,最高达28.18kg/(mm·hm~2);水分充足时夏玉米高产高效的最优方案为:W3(400mm)+F3(N-P-K:180-120-135kg/hm~2)+L1(液膜0kg/hm~2)。     

废胶粉/NR共混胶料力学性能的研究

研究了共混方法、共混时间、废胶粉的用量以及废胶粉经间苯二酚(R)和六次甲基四胺(H)改性后对废胶粉/NR共混胶力学性能的影响。结果表明,共混方法、共混时间及废胶粉用量均对共混物硫化胶的力学性能有影响;通过对废胶粉的改性,可以大大提高废胶粉/NR共混物硫化胶的力学性能,当改性剂间苯二酚和六次甲基四胺质量比为1/0.5时,胶料力学性能最佳,其拉伸强度达到17.03MPa。