不同阶段猪用颗粒饲料物理性能的对比分析

对某饲料厂不同阶段猪用4种颗粒饲料的物理性能包括直径、长度、硬度、容重、含粉率和耐久性指数（Pellet Durability Index, PDI）等进行测定,对结果进行归类总结并采用统计学的方法参照有关标准进行分析。结果表明,4种颗粒饲料直径在2.87~3.94 mm之间,母猪料直径最大,小猪料最小,两两之间差异显著（P<0.05）,而且随着猪只年龄的增加,颗粒饲料的直径呈递增趋势。颗粒长度在8.62~11.94 mm之间,以大猪料最长,小猪料最短,长径比偏高。颗粒硬度在3.86~6.47 kg之间,以大猪料最大,小猪料最小,中小猪料显著低于大猪料和母猪料（P<0.05）,只有小猪料符合有关要求。颗粒容重在576.7~614.6 g/L之间,母猪料最大,小猪料最小,两两之间差异显著（P<0.05）,与直径呈相同的增减趋势。含粉率以小猪料最大,且只有小猪料与大猪料之间差异显著（P<0.05）。颗粒PDI以大猪料最大,小猪料最小,各阶段猪料的含粉率和PDI均符合有关要求。建议饲料厂家注重颗粒饲料物理性能指标的控制,调整饲料配方和工艺参数,不断改进颗粒饲料的质量。     

纳米压痕技术在木材科学中的应用

纳米压痕技术是在亚微米尺度下决定一种材料机械属性的测试方法。文中对纳米压痕技术的测试原理及其在木材科学中的应用现状进行了较为详细的论述。     

Hardness distribution on wood surface

For better understanding wood hardness, we developed a new hand-operated hardness tester that works with Brinell's method. With this tester we investigated the hardness distribution of wood minutely using a 2mm diameter ball tip. The following results were obtained: (1) On preliminary examination with medium-density fiberboard, we found that the value of Brinell's hardness decreased with the increase in the tip ball's diameter but that it was almost constant with the indenting velocity. (2) By using a small diameter tip, the difference of the hardness became clearer between earlywood and latewood. (3) With radial and tangential sections, we obtained hardness distribution patterns similar to those of wood grain. It seems that the hardness distribution reflects the distribution of density on wood surfaces.     

Maize kernel color depends on the interaction between hardness and carotenoid concentration

Maize kernel color and carotenoid concentration are traits valued by the food industry to ensure the quality of their products. Correlations between color and carotenoid concentration have been extensively reported. Based on the concept that chromaticity is modified differently by opaque and translucent materials, we tested the hypothesis that maize kernel color is not only the result of total carotenoid concentration but also a consequence of kernel hardness. Kernel hardness (test weight, vitreousness, and floaters percentage), carotenoid concentration, and color (HunterLab) were measured in thirteen commercial hybrids. Genotypes showed significant differences in all analyzed kernel hardness traits, carotenoid concentration (24.7–39.4 mg kg⁻¹), and HunterLab color dimensions. Kernel color values and kernel hardness were correlated. Genotype differences in b (yellowness) were observed in kernels with similar total carotenoid concentration but contrasting hardness. For a similar carotenoid concentration harder genotypes always showed lower b values. When whole kernels were milled and color was measured on the resulting flour, genotype differences in yellowness disappeared, further supporting that the kernel vitreous structure affects kernel color. Our results sustain the notion that the genotype capacity to form larger proportions of vitreous endosperm impacts color regardless of total carotenoid concentration.     

3份小麦品种（系）Gsp 1基因的克隆及序列分析

根据已报道的谷类作物硬度基因grain softness protein-1(Gsp-1)保守DNA序列设计一对特异性引物,以优质小麦品种(系)中国春、SZ-56及M9876基因组DNA为模板进行基因扩增、克隆和序列测定,获得636 bp的Gsp-1全长特异性片段。序列分析显示其含有495 bp完整的开放阅读框,编码全长为164 aa的蛋白,该蛋白含有Gsp-1典型的19 aa信号肽,10个保守的半胱氨酸以及2个保守的色氨酸。序列比对表明,Gsp-1基因不仅含有Gsp-1 a、Gsp-1 b和Gsp-1 c这3种类型,还含有一种新的类型,将其命名Gsp-1 d。进一步对其结构预测分析发现,Gsp-1蛋白可形成5个链间二硫键,含有4~5个α-螺旋。进化树分析显示Gsp-1基因与硬度主效基因Pina和Pinb有着紧密关系。     

桃硬度与果实部分性状的相关性研究

以16个桃品种为试材,研究不同品种桃果实硬度与其果实性状之间的关系。结果表明,桃果实的果肉硬度与Vc含量呈极显著相关性,相关系数为0.72;桃果实果皮硬度与Vc含量呈显著相关性,相关系数为0.52;桃果实果肉硬度与可溶性果胶含量呈显著相关性,相关系数为0.58;不同品种桃果实的Vc含量与可溶性果胶含量呈显著相关性,相关系数为0.58。     

浅析影响小麦硬度指标测定的诸多因素

介绍影响小麦硬度的因素,从小麦水分、样品数量、小麦不完善粒含量等因素进行分析。     

纳米Al_2O_3改性水性木器漆耐磨性和硬度的研究

为提高水性聚丙烯酸酯木器漆的耐磨性和硬度,进行纳米Al2O3浆料的制备及其对水性木器漆改性的研究,探讨分析不同制备方法和Al2O3添加量对漆膜耐磨性和硬度的影响。结果表明:以聚丙烯酰胺为分散剂、聚乙二醇和辛基酚聚氧乙烯醚为润湿剂、聚乙烯吡咯烷酮为稳定保护胶,在高速搅拌下制成的纳米Al2O3浆料,在透射电镜下观察发现纳米Al2O3颗粒分布均匀,具有良好的分散性;在不影响漆膜透明度的情况下,漆膜耐磨性和硬度随Al2O3添加量增加得到提高,添加量在1.5%时漆膜具有较好的耐磨性和硬度;纳米杂合工艺法的漆膜耐磨性和硬度优于后添加法制备的水性木器漆涂膜。     

棉秆拉拔阻力的研究

为研究收获期的棉秆根部直径和土壤硬度对棉秆拉拔阻力的影响,为棉秆拔秆收获机械的设计和使用提供参考依据,在山东省无棣县棉花生产全程机械化示范基地进行了棉秆拔秆试验,采集了棉秆拉拔阻力、根部直径和土壤硬度的数据。试验结果表明:在较长时间跨度里,棉秆的拉拔阻力变化很大,呈先增大后减小的趋势。已采集的6批次数据中,第2批次(2014.12.26)棉秆拉拔阻力最大,单株棉秆最大拉拔阻力为1031.6N,平均拉拔阻力为679.0N;第6批次(2015.03.21)棉秆拉拔阻力最小,单株棉秆最大拉拔阻力达到471.1N,平均拉拔阻力为340.76N。对采集的数据进行的回归分析表明:同批次的棉秆拉拔阻力与棉秆根部直径成正相关关系,直线回归关系不显著;同批次的棉秆拉拔阻力土壤硬度成正相关关系,直线回归关系不显著。     

35CrMo旋转接头激光表面硬化技术的试验研究

用L9(34)正交试验法研究35CrMo旋转接头激光相变硬化工艺参数优化组合,分析了旋转接头激光相变硬化方法.试验结果表明:激光相变硬化层硬度比渗氮淬火提高了30%,耐磨性提高了1倍,表面残余应力为压应力;满足了旋转接头工作要求,为改进旋转接头表面处理方法提供了依据.