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甘蔗机械化收获后的宿根性能分析 总被引:1,自引:0,他引:1
为了探讨机械化收获后甘蔗的宿根性能,筛选适宜机械化收获的品种,本文以国家甘蔗产业技术体系集成示范品种为主要供试材料,分析了土壤紧实度与甘蔗宿根萌芽率之间的关系,并比较了各品种间机械化收获后宿根性能表现。结果表明,机械化收获的土壤紧实度显著高于人工收获,甘蔗的宿根发株率与土壤的紧实度呈显著的负相关;供试品种当中,桂糖31号、福农38号、柳城05-136、柳城03-1137、粤甘24号等几个品种在机收后土壤紧实度较高的情况下宿根发株率相对较高,表现出了适应机械化收获的性能。 相似文献
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以硫酸盐法对带皮和去皮的桦树、山毛榉、橡树和白杨木片进行单独蒸煮和混合蒸煮。白杨制浆的收获率最高,其次为桦木,山毛榉和橡木。混合料的收获率相当于根据混合料中各种木材比例及每种木材单独蒸煮收获率计算的结果。未去皮木材比已去皮木材蒸煮收获为低。对于桦木和橡木,加入皮能使浆的收获率稍增;而对于白杨和山毛榉,加入皮减少浆的收获率。蒸煮器中存在皮时,要延长蒸煮时间,同时对一定的产浆量来说,使用的化学药剂也较高。带皮的浆颜色较深,然而易于漂白。它的打浆性能较好,然而它的技术特性比去皮浆差。山毛榉浆的强度最低,在加入其他木材,特别是桦木和白杨以后,生产的浆的性质能改善。 相似文献
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轻工业部造纸工业双革调查组 《中国造纸》1975,(6)
山东掖县造纸厂,多年来一直以麦草为主要原料,经过碱法蒸煮、洗选漂,用双网双缸纸机生产凸版纸、书写纸等品种。过去曾一度出现麦草浆收获率较低,碱耗较高的生产局面。 为了提高麦草浆收获率,降低碱耗,厂党支部认真贯彻《鞍钢宪法》,坚持政治挂帅,加强党的领导,大搞以提高麦草浆收获率、降低碱耗为内容的增产节约群众运动。广大群众大搞技术革新,改革工艺,改造老设备,在提高麦草浆收获率、降低碱耗方面收到了 相似文献
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Sweetpotatoes were grown under four cultivation conditions, i. e. early planting and early harvesting (I, E‐E), standard (II, STD), early planting and late harvesting (III, E‐L), and late planting and late harvesting (IV, L‐L). Retrogradation of the starch isolated from fresh roots was estimated by the hardness and syneresis rate after two weeks of storage at 5 °C. A significant difference in retrogradation among the cultivation conditions and cultivars was observed. The starch tended to exhibit slower retrogradation in late harvesting, where the temperature was low. The differences in amylose content and the proportion of short unit‐chains (DP 9‐11) of amylopectin among cultivation conditions were also significant. Starch retrogradation was positively correlated with the proportion of chains with DP 12‐14 but negatively correlated with the proportion of DP 9‐11. Moreover, there was no significant correlation between amylose content and retrogradation. These results indicate that the main factor for retrogradation under any cultivation condition is the proportion of short unit‐chains of amylopectin. The best performance of sweetpotato starch as a food ingredient would be achieved by selecting both the proper cultivar and cultivation conditions. 相似文献
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Karol Lizarazo Beatriz Fernández‐Marín José María Becerril José Ignacio García‐Plazaola 《Journal of the science of food and agriculture》2010,90(12):1994-1999
BACKGROUND: Tocopherol (vitamin E) is an antioxidant essential in human nutrition. Several approaches have aimed to enhance tocopherol content in crops by the genetic modification of plants, a practice that generates some social concern. As tocopherol accumulates with leaf age in some wild plants and the antioxidant mechanisms respond with flexibility to stress conditions, it is hypothesised that tocopherol content can be increased in edible plants by the manipulation of harvesting time and growth conditions, in particular irradiance. RESULTS: Ontogenic changes in tocopherol concentration have been studied in photosynthetic tissues of edible leaves (lettuce, spinach, corn salad and dandelion) and green fruits (cucumber and pepper). In all species, tocopherol content increased with tissue age. Spinach showed the fastest rate of tocopherol accumulation, and growth at higher irradiance had a synergistic effect on the rate of accumulation. The same irradiance dependence of this accumulation was observed in fruits, but a final decrease with senescence occurred in cucumber. CONCLUSION: This study demonstrates that the content of tocopherol in vegetables can be notably enhanced (or reduced) by simply selecting the appropriate harvesting time and/or by manipulating the environmental conditions during the growth period. Copyright © 2010 Society of Chemical Industry 相似文献
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Canola grain containing 18–20% moisture during harvesting is not suitable for safe storage. The storage conditions for these grains need to be optimized through drying technique to prevent both fungal attack and suppression in germination. Hence, the present investigation has been carried out to analyze coupled heat and mass transfer phenomena during steady state counter flow deep bed drying. To carry out this study, a non-equilibrium drying model has been developed. Governing equations include moisture mass balance, enthalpy balance, heat transfer rate, mass transfer rate for an element along bed height. And diffusion equation of moisture inside a single kernel has also been solved simultaneously through an implicit scheme using TDMA (Tri-Diagonal Matrix Algorithm). An iterative approach has been used to solve the governing equations for a selected geometry of the dryer. The rating analysis can be used for arriving at improved quality and higher efficiency at reasonable level of throughput. 相似文献
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我国整秆与切段2种甘蔗收获方式发展历程与前景分析 总被引:3,自引:0,他引:3
进入21世纪以来,甘蔗机械化收获技术在我国得到重视和发展。尽管整秆式收割机技术水平和可靠性在逐步提高,几家生产该类收割机的厂家仍相继陷入停产危机。进口切段式收割机价格昂贵,在我国使用中作业效率低,国产切段式收割机在性能和可靠性方面与进口同类机型还存在较大差距。甘蔗收割机生产企业、科研单位、甚至政府决策部门都面临着我国甘蔗收获技术应如何发展的困惑。本文在综述国内外甘蔗收获技术发展历程的基础上,结合我国甘蔗生产立地条件和经营模式,分析了整秆式与切段式2种技术路线在我国的发展前景,并提出相关建议。 相似文献
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研究一类由周期logistic模型描述的种群系统的脉冲优化控制问题.在给定时刻对种群同时进行比例和常量脉冲收获,在系统保持周期变化的前提下,考虑收获成本因素,以最大经济净收益为目标,研究收获努力量及收获常数对收益的影响,并确定最优的脉冲收获控制策略.利用关于脉冲微分系统的极值原理和一些分析技巧,获得了最优控制策略及最优收益的确切表达式. 相似文献
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针对‘檀香’橄榄果实冷藏期间易发生冷害现象,本实验研究了7 个采收期(Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ、Ⅶ)对(2±1)℃、相对湿度85%~90%条件下冷藏橄榄果实冷害的影响。定期测定贮藏期间橄榄果实冷害指数、果皮褐变指数、果实好果率和质量损失率、果实呼吸强度和细胞膜相对渗透率、果实表面色度角、果皮叶绿素含量、果肉可溶性固形物、可滴定酸、可溶性总糖和还原糖含量的变化。结果表明:与采收期Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅵ、Ⅶ相比,采收期Ⅴ能保持冷藏橄榄果实较低的冷害指数、果皮褐变指数、果实质量损失率和较高的好果率,降低果实呼吸强度和呼吸峰值,延缓果实细胞膜相对渗透率升高,保持中后期较高的果实表面色度角、果皮叶绿素含量、果肉可溶性固形物、可滴定酸、可溶性总糖和还原糖含量。因此认为,采收期Ⅴ可作为减轻冷藏‘檀香’橄榄果实冷害发生的适宜采收成熟度。 相似文献
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本文叙述了鲜黄瓜自然条件下失水率的试验和黄瓜保鲜贮运的方法。试验表明,鲜黄瓜在自然条件下的脱水速率由快变慢;从存放的第二天开始脱水速率与黄瓜直径和质量显著负相关,而第一天的相关性不明显。黄瓜的失水速率与环境的相对湿度显著负相关。对国内外黄瓜保鲜包装贮运的方法进行了简述;鲜黄瓜的贮运采用必要合理的包装和低温贮藏可防止黄瓜脱水和发黄老化,有效延长黄瓜的货架寿命。并简要介绍鲜黄瓜分级、保鲜包装、贮藏、运输的相关标准。 相似文献
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研究一类具有双密度制约的HollingⅡ类功能反应的捕食系统收获模型,运用微分方程定性稳定性理论分析了模型平衡点的性态,给出了系统极限环不存在的充分条件,利用Pontryagin最大值原理得到系统的最优捕获策略. 相似文献
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纽荷尔脐橙冷藏的最适采收期 总被引:3,自引:0,他引:3
以纽荷尔脐橙为原料,研究不同时期采摘果实耐贮性,通过分析品质、腐烂和冷害发生规律,确定冷藏脐橙最佳采收期。结果表明:贮藏结束时,脐橙糖酸比上升,而总糖、可滴定酸(titratable acid,TA)和VC含量均显著下降。在2012年10月下旬和11月上旬采摘的果实,鲜果和贮藏果有机质含量均较低,至贮藏结束,总糖、TA和VC含量均减少,且以TA含量下降最为明显。11月下旬到12月上旬采摘的果实,至贮藏结束时,TA和VC含量降低,但相比其他组的果实下降率最低。12月中旬之后采摘的果实,品质方面与11月下旬到12月上旬采摘的果实差距不大,但果实腐烂率高达9.67%。研究表明,冷藏的纽荷尔脐橙最适采摘期为11月中旬到12月上旬。 相似文献