首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
采用土培试验,以甘蓝型油菜为供试作物,研究了陕西渭北旱塬低硒、低锌土壤上,硒、锌对甘蓝型油菜产量和营养品质的影响。试验结果表明,硒对油菜生物量和产量没有明显的影响。锌或硒锌配施对油菜生物量和产量有增加趋势;施硒促进油菜籽对钾、硒元素的吸收累积,而在一定程度上抑制了磷、硫、钙和镁元素的吸收。施锌促进油菜对钾、钙、铁、锰、铜、锌、硼的吸收累积,而对氮、硫的吸收有抑制作用。硒锌配合施用有利于促进油菜对硒、锌的吸收累积,而对铁的吸收有一定的抑制作用;施硒对油菜籽含油量、芥酸有增加趋势,对蛋白质、硫甙含量有降低趋势。施锌对油菜籽含油量有增加趋势,对蛋白质、硫甙、芥酸有降低趋势。硒锌配施,油菜含油量、蛋白质、硫甙无变化,芥酸明显下降。  相似文献   

2.
“人文”是哲学中的一个术语,是对人的关注,是人作为社会的个体,作为社会的成员,对其的关注、关心、尊重、理解和支持。人文引申为人文关怀。人文关怀最为基本的是对人的生存状态、生理需求、基本生活的关注,而在此基础上是对人格尊严、名誉、地位、需求的关注、关心,因此,人文关怀集中体现为以人为本,对人的生存、发展的关心、关注,对人的情感、精神的理解,对人的社会发展的尊重。  相似文献   

3.
根据近期中东市场对弹力网眼童袜裤的需求,按照袜筒编织工艺、裁剪、缝纫、整装工艺的特殊要求,对国产Z506型袜机进行了必要的改进,同时对有关零部件和专用器具进行设计与制造,生产出高质量的弹力网眼童袜裤。文中对产品规格标准、织造、染漂、裁剪、缝纫、整装等工艺流,程进行了详细介绍,并对有关技术问题提出了解决办法。  相似文献   

4.
知之者不如好之者,好之者不如乐之者。民族品牌的文化烙印最终可归结到对品牌、对消费者、对文化、对价值观、对世界的态度。以创新之精神,揭开民族封印,中国品牌将大放华采。  相似文献   

5.
通过实验对真空辅助树脂灌注成型的树脂流道和真空通路进行研究,对于点对点、线对点、点对线、线对线、环形对点这几种流道设计方式进行验证,发现线对点注入以及环形对点注入可以获得最佳的纤维浸润性,相比较而言,线对点注入方式更加经济,在0.085MPa、0.095MPa两种不同的真空度条件下,后者成型的制品力学性能总体较好。  相似文献   

6.
研究了日粮不同硒、锌和铜水平及互作效应对肉鸡胸肌中铜、锌、铁、钙、锰含量的影响.选用1日龄罗斯308肉仔鸡720只,随机分为9个处理组.在玉米-豆粕型日粮基础上添加不同水平的蛋氨酸硒、甘氨酸锌和甘氨酸铜,以饲喂基础日粮组为对照组,试验期7周.结果表明:1)日粮不同硒水平对前中期胸肌铜含量的影响显著,对中期胸肌锌含量影响极显著,对后期胸肌铁含量影响显著,对前中后期胸肌钙含量影响不显著,对前期胸肌锰含量影响显著;2)日粮不同锌水平对前中后期胸肌铜含量影响显著,对中期胸肌锌含量影响极显著,对中期胸肌铁含量影响显著,对前期胸肌锰含量影响显著,对前中后期胸肌钙含量影响不显著;3)日粮不同铜水平对前中期胸肌铜、锌含量的影响显著,对后期胸肌锰含量影响显著,对前中后期胸肌铁、钙含量影响不显著;4)硒、锌和铜的交互作用对前中后期胸肌铜、锌、锰含量影响显著,特别是中期胸肌铜、锌含量影响极显著,对中后期胸肌铁含量影响显著,对中期胸肌钙含量影响显著.  相似文献   

7.
目的:测试橄榄提取物对食品生产、加工和贮藏中常见的腐败菌的抑制作用,寻找橄榄抑菌作用的活性部位.方法:采用抑菌圈法测试橄榄提取物对大肠杆菌、金黄色葡萄球菌、枯草杆菌、啤酒酵母、黑曲霉、黑根霉、青霉等细菌,酵母菌,霉菌的抑制作用,橄榄三个提取部位对金黄色葡萄球菌、枯草杆菌、大肠杆菌的抑制作用.结果:橄榄提取物对测试菌种中的细菌和酵母菌有一定的抑制作用,但对霉菌几乎没有抑制作用.橄榄乙酸乙酯部位对金黄色葡萄球菌、枯草杆菌、大肠杆菌有较强抑制作用.结论:橄榄提取物对细菌和酵母菌有一定的抑制作用,乙酸乙酯部位为橄榄抑菌活性部位.  相似文献   

8.
卷烟消费倾向的区域性差异   总被引:1,自引:0,他引:1  
为研究区域性差异对卷烟消费倾向的影响,对杭州、广州、成都、沈阳和兰州随机抽取的消费者给“利群”牌卷烟1 1个烟气吸味评价指标的评吸打分及其重要性排名进行了统计分析.结果表明:5市的消费者对“利群”牌卷烟的感受不同;对卷烟烟气的香气质量、香气饱满程度、余味舒适度和细腻度的关注度普遍较高,对其他指标的要求存在明显的区域差异:杭州的消费者对卷烟的刺激性,广州对回甜感,成都对烟气劲头和浓度,沈阳对回甜感和劲头,兰州对杂气、干燥感和浓度的诉求较高.区域不同,消费者对卷烟的消费倾向不同.  相似文献   

9.
冰糖橙皮色素的提取及稳定性研究   总被引:1,自引:1,他引:0  
对冰糖橙皮色素的提取条件以及温度、pH、光照、氧化剂、还原剂、金属离子等对冰糖橙皮色素稳定性的影响进行了系统研究.结果表明,料液比1∶8(g/mL)、60℃恒温、95%乙醇(pH5.0)浸提6 h,色素提取率达35.76%.色素在pH值2~8,温度60℃以内比较稳定;光照能加快色素降解;K 、Na 、Mg2 、Zn2 对色素有一定的增色护色作用;而Cu2 对色素色泽无影响,Ca2 对其有不良影响,色素对氧化剂和还原剂耐受力较强,食品添加剂对色素无影响.因此,冰糖橙皮色素作为食用色素具有很好的开发价值.  相似文献   

10.
试验结果表明:浓度为1:15000的赤霉素药液对果蔗的多数农艺性状、全部产量性状、多数商品性状、工艺性状及抗螟性等均有正效应,对果蔗的少数农艺性状、商品性状和抗病性等有轻微负效应,是本试验中对果蔗效果最佳的浓度;浓度为1:5000的赤霉素药液对果蔗产量性状、工艺性状具有显著正效应,对果蔗农艺性状、少数工艺性状、抗螟性等具有明显正效应,对少数商品性状、极少数工艺性状有轻微负效应,是本试验中对果蔗效果位居第2的浓度;浓度为1:7500的赤霉素药液对果蔗农艺性状、产量性状、多数商品性状和抗螟性等具有正效应,对少数产量性状、商品性状和个别工艺性状具有负效应,是本试验中对果蔗效果位居第3的浓度.  相似文献   

11.
杨恒  张素风 《上海造纸》2011,(2):25-27,43
该文对蒸煮前采用热水预处理法,提取植物纤维原料中半纤维素的工艺进行了分析和综述。抽提出的半纤维素可以用来生产燃料乙醇或乙酸等化学品,抽提后的植物纤维原料仍可用于制浆造纸。  相似文献   

12.
The free sugars, water-soluble gums, and hemicelluloses have been isolated from four barley grain samples [Hordeum vulgare (L.)], and from their commercial malts. Arabinose, xylose, galactose, glucose, fructose, maltose and sucrose occur as free sugars in the grains and the proportions of these sugars increase on malting. Mannose also occurs as a free sugar in the malts. The water-soluble gums contain arabinose, xylose, lesser amounts of mannose and galactose, and varying amounts of glucose. The aqueous-ethanol supernatants from the hot-water extracts are glucans of low molecular weight. The hemicellulose A polymers contain arabinose, xylose, mannose and glucose. Wide variations in the mannose and glucose contents were observed in these polysaccharides. The hemicellulose B polymers are arabinoxylans, containing lesser amounts of galactose and glucose. The aqueous-ethanol supernatants from the hemicellulose B precipitations contain arabinose, xylose, mannose, galactose and glucose. These polysaccharides differ markedly from those present in the aqueous-ethanol supernatants of the hot-water extracts. All polysaccharides are modified to varying degrees during malting.  相似文献   

13.
在传统的化学法制浆过程中,植物纤维原料中的半纤维素蒸煮时会降解到蒸煮废液中,得不到有效利用。结合生物质精炼理念,可以在蒸煮前提取出部分半纤维素,提取出的半纤维素可以用于生产生物质乙醇等化学品,提取后的植物纤维原料仍用于制浆造纸。热水抽提法是目前提取半纤维素的最有效方法之一。本文对热水抽提法提取半纤维素工艺的原理、研究进展及发展前景进行了分析与综述。  相似文献   

14.
杨木木片硫酸盐制浆前,进行缓和的碱抽提处理,抽提出半纤维素用作生物燃料(生物乙醇),在温度90℃,NaOH 1~2M,液比1∶4条件下进行碱处理,不需要高压设备,每吨木片得到半纤维素40~50kg,经碱抽提后木片进行硫酸盐蒸煮,与未经碱抽提木片参照对比,纸浆得率基本相同,但是需要很好地控制碱抽提与硫酸盐蒸煮工艺条件,能缩短蒸煮时间和节省化学品用量。碱预抽提木片得到的硫酸盐纸浆中纤维素/半纤维素的比率稍高,导致纸浆的抗张指数稍有降低(约10%),但是纸浆白度较高且筛渣含量低,为使硫酸盐纸浆的质量和得率保持较高水平,采用缓和的碱预抽提,使半纤维素得率较低,而回收的半纤维素的浓缩和离析比木片自水解或稀酸水解回收糠醛更加容易。  相似文献   

15.
在不同温度条件下,对麦草制浆前进行热水预抽提处理,然后制备化学机械浆,探讨热水预抽提对麦草化机浆浆料性能的影响。研究结果表明:麦草经过热水预抽提后,其化机浆的抗张强度、撕裂度和耐破度均有所提高,碱浸渍段用碱量降低,打浆能耗降低,但纸浆得率有不同程度的下降。  相似文献   

16.
Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.  相似文献   

17.
在麦草蒸煮之前进行热水抽提,将抽提后的麦草与未抽提的麦草在相同反应条件下进行烧碱–蒽醌法制浆,探讨热水抽提对麦草碱法制浆后浆料性能的影响。热水抽提后麦草的制浆结果表明:抽提后麦草的蒸煮脱木素率提高,卡伯值下降,但是,浆料得率均有不同程度的降低。经过热水抽提,麦草碱法制浆性能提高,可以降低用碱量,缩短蒸煮保温时间。在本实验条件下,热水抽提的较佳工艺条件为:抽提最高温度140℃,升温时间30min,保温时间60min,液比1:10;后续蒸煮的较佳工艺条件为:用碱量12%(以NaOH计),蒸煮最高温度155℃,升温时间90min,保温时间30min,液比1:5。  相似文献   

18.
Feeding fat to lactating dairy cows may reduce methane production. Relative to cellulose, fermentation of hemicellulose is believed to result in less methane; however, these factors have not been studied simultaneously. Eight multiparous, lactating Jersey cows averaging (±SD) 98 ± 30.8 d in milk and body weight of 439.3 ± 56.7 kg were used in a twice-replicated 4 × 4 Latin square to determine the effects of fat and hemicellulose on energy utilization and methane production using a headbox-type indirect calorimetry method. To manipulate the concentration of fat, porcine tallow was included at either 0 or 2% of the diet dry matter. The concentration of hemicellulose was adjusted by manipulating the inclusion rate of corn silage, alfalfa hay, and soybean hulls resulting in either 11.3 or 12.7% hemicellulose (dry matter basis). The resulting factorial arrangement of treatments were low fat low hemicellulose (LFLH), low fat high hemicellulose (LFHH), high fat low hemicellulose (HFLH), and high fat high hemicellulose (HFHH). Neither fat nor hemicellulose affected dry matter intake, averaging 16.2 ± 1.18 kg/d across treatments. Likewise, treatments did not affect milk production, averaging 23.0 ± 1.72 kg/d, or energy-corrected milk, averaging 30.1 ± 2.41 kg/d. The inclusion of fat tended to reduce methane produced per kilogram of dry matter intake from 24.9 to 23.1 ± 1.59 L/kg, whereas hemicellulose had no effect. Increasing hemicellulose increased neutral detergent fiber (NDF) digestibility from 43.0 to 51.1 ± 2.35%. Similarly, increasing hemicellulose concentration increased total intake of digestible NDF from 6.62 to 8.42 ± 0.89 kg/d, whereas fat had no effect. Methane per unit of digested NDF tended to decrease from 64.8 to 49.2 ± 9.60 L/kg with increasing hemicellulose, whereas fat had no effect. An interaction between hemicellulose and fat content on net energy balance (milk plus tissue energy) was observed. Specifically, increasing hemicellulose in low-fat diets tended to increase net energy balance, but this was not observed in high-fat diets. These results confirm that methane production may be reduced with the inclusion of fat, whereas energy utilization of lactating dairy cows is improved by increasing hemicellulose in low-fat diets.  相似文献   

19.
本文研究了热水预抽提对南方松碱法制浆过程的影响。结果表明:热水预抽提可使蒸煮过程中黑液固形物含量和木素的溶出量增加,提高后续蒸煮过程中有效碱的作用效率。合适时间的热水预处理可使木片具有更好的制浆性能,但预处理时间过长会导致蒸煮后成浆强度下降。  相似文献   

20.
以XAPMP浆的废液中分离的半纤维素为原料,通过醚化反应制备不同取代度的季铵型半纤维素。主要讨论了醚化剂、催化剂用量、反应时间及温度对取代度的影响。结果表明,当醚化剂与半纤维素质量之比值为1.0,NaOH与半纤维素质量之比值为0.06时,反应时间为4h,温度为55℃时,可得到取代度为0.08的季铵型半纤维素。通过红外光谱对改性前后半纤维素的结构进行表征。改性后的季铵型半纤维素对阔叶木浆、针叶木浆以及OCC纸浆有明显的增强作用。研究表明取代度越高的半纤维素对纸浆的增强作用越显著。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号