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采用单因子实验及均匀实验设计,考察了影响丙脒盐酸盐收率的因素,经回归分析,得出了合成丙脒盐酸盐的优化工艺条件:物料配比n(CH3CH2CN)﹕n(CH3OH)﹕n(HCl)=1﹕1.1﹕1.1;整个反应体系为无水体系;在反应前期,溶液温度为0~10℃,pH值为4.0左右,反应时间为9 h;在反应后期,溶液温度为0~20℃,pH值为8.0~8.5;氨-甲醇溶液的质量分数为15.0%。在此优化工艺条件下,丙脒盐酸盐的收率为94.0%,含量≥99%。 相似文献
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以凡纳滨对虾为原料，以ACE抑制率为指标，利用响应面法对虾肉蛋白自溶制备ACE抑制肽的工艺条件进行了优化，即在酶解条件（pH值、温度、虾头虾肉质量比）和ACE（Angiotensin I-converting Enzyme，ACE）抑制率之间建立了数学模型Y=23．59—0．21X1＋0．84X2＋0．85X3—0．71X1^2-0．94X2^2-1．06X3^2＋0．088X1X2—0．46X1X3-0．87X2X3。分析表明，在3个因素中，虾头与虾肉比例对ACE抑制率的影响最为显著。优化后的工艺参数为：pH7．35，温度57．2℃，虾头与虾肉比例为1：1。根据回归方程的预测结果，反应时间为4h，其ACE抑制率达41．9％。 相似文献
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采用单因素和正交优化实验19（43）确定酶法自溶罗非鱼下脚料的最适条件，结果表明，最适自溶条件为：料液质量比1：3，反应温度50％，pH7．5，反应时间6．5h；酶解结束蛋白质回收率为81．75％。 相似文献
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从甲壳素出发，先制备了3种不同脱乙酰度的壳聚糖，选择过硫酸铵-亚硫酸氢钠为氧化还原体系引发剂，合成了壳聚糖接枝丙烯酰胺聚合物；通过红外光谱，电镜扫描对聚合物进行结构表征，结果表明壳聚糖结构发生了变化，通过在相同条件下比较壳聚糖不同脱乙酰度对接枝率的影响，得出了在脱乙酰度为68．5％时聚合物的接枝率最大为250％，其最佳合成工艺为：m（壳聚糖）：m（丙烯酰胺）=1：5，引发剂用量为体系质量分数的0．3％～0．4％，温度55～60℃，反应时间为2．5～3．0h。 相似文献
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酶解法提取鱼油的工艺参数优化 总被引：1，自引：0，他引：1
利用蛋白酶酶解法从黄鳍金枪鱼（Thunnus albacares）加工的下脚料——鱼头中提取鱼油。以鱼油提取率和感官特征为指标，通过正交优化实验设计，获得了胰蛋白酶提取鱼油的最佳酶解工艺参数：酶解温度45℃，酶添加量1．5％．料液质量比1：1，酶解时间4h，酶解pH8。在该条件下．鱼油的提取率为4．34％，理化指标除过氧化值外均达到SC／T3502-2000的粗鱼油二级标准。多不饱和脂肪酸总含量高达38．47％,其中DHA和EPA的含量分别为23．63％和4．84％。 相似文献
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几株有益芽孢杆菌对温度、制粒工艺及pH值的耐受性 总被引：4，自引：0，他引：4
报道了实验室分离、筛选的5株有益芽孢杆菌对温度、对虾饲料制粒工艺流程和pH值的耐受性。结果表明，5株芽孢杆菌经80℃水浴40min后全部存活，90℃水浴20min有35％-70％存活，100℃水浴10min仍有30％-50％存活，显示所筛选的5株芽孢杆菌对高温有较强的耐受力；在对虾饲料中添加5株芽孢杆菌，经整个生产工艺流程后芽孢杆菌存活95％，烘干后芽孢杆菌存活93％，说明杆菌能够承受饲料制粒生产中压力、温度和水分的变化；当pH值为3．8、4．6、5．2时，分别有l、3、5株菌能繁殖，pH值6．0-8．5时，5株菌生长旺盛，将5株菌经pH值2．2—4．6处理1h，再接种在pH值7．2的培养基可以良好生长，说明杆菌在酸性环境中生长性能较差，在弱酸性和碱性环境中生长旺盛；能耐受酸性环境而存活，再给予适宜环境即能良好生长。5株芽孢杆菌具有作为水产硬颗粒饲料专用益生素菌株的优势。 相似文献
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木瓜蛋白酶在制取青鳞鱼可溶性蛋白中的应用 总被引：6，自引：1，他引：5
研究了木瓜蛋白酶的酶解温度，酶浓度，酶解时间，加水量，pH值对青鳞鱼可溶性蛋白得率的影响，探讨了α－氨态氮含量与青鳞鱼与可溶性蛋白得率的关系。结果表明：温度小于50℃，随着酶解温度的提高，酶浓度的增加，酶解时间的延长青鳞鱼可溶性蛋白得率及α－氨态氮的含量均增加，α＝氨态氮含量增加比可溶性蛋白得率的增加明显；加水量的增加，可溶性蛋白得率增加；pH值对水解效果及可溶性蛋白得率影响不大。综合考虑，最佳水解条件为：温度50℃，酶浓度为1500u/g，酶解时间80min,m原料：m水＝1：2，pH6.8。酶解所得可溶性蛋白经氨基酸分析仪检测,其氨基酸总量为49.47mg/mL，必需氨基酸占氨基酸总量的41．0％，游离氨基酸含量为6.3mg/mL，肽含量为87．2％。 相似文献
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米曲霉中性蛋白酶特性的研究 总被引：2，自引：0，他引：2
研究了米曲霉中性蛋白酶的特性。结果表明，米曲霉中性蛋白酶的最佳提取方法为加入pH7．2的缓冲液研匀，置恒温（30℃）培养箱中提取30min．每10min搅动1次，最后用4层纱布过滤。酶反应最适温度为55℃，最适pH值为7．2。NaCl和EDTA对其有一定的抑制作用。酶的热稳定性好．在45℃的温度下处理24h后，酶活力仍有45．5％。米曲霉中性蛋白酶与培养物一起保存时，稳定性也较好，在4℃保存一个月后，酶活力几乎无变化。 相似文献
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以Cu2O粒子为光催化剂，太阳光为光源，研究了Cu2O粒子对可溶性染料罗丹明B的光催化降解情况。并考察了不同光源，光照时间，催化剂用量，双氧水加入量和溶液的酸度等对罗丹明B光催化降解过程的影响。结果表明，Cu2O粒子在太阳光照射下，能较好地降解罗丹明B，其最佳反应条件为：罗丹明B浓度为5mg／L，催化剂（Cu2O）为0．75g／L，pH值为5．2，H2O2加入量1．0％，反应时间25min。此条件下，罗丹明B的降解率达到100％，即与在500W高压汞灯紫外（λ=365nm）光照有相同的降解效果。 相似文献
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粗鱼油通过精炼可以除去非甘油三酯杂质成分，研究表明黄鳍金枪鱼鱼油精炼的工艺参数为：800g，L的H3PO4脱胶，添加量为油量的1％（体积分数）；300g／L的Na0H脱酸，添加量为油量的2％（体积分数）；活性土脱色。添加量为油量的10％（质量分数）；85℃下减压蒸馏脱臭15min。经过精炼，鱼油呈淡黄色，澄清透明，有淡鱼腥昧，理化指标达到鱼油SC/T3502—2000标准的精制鱼油一级要求，精制鱼油中PUFA的总含量（w）达37．06％，DHA和EPA含量（w）分别为25．10％和4．45％。 相似文献
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Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area. 相似文献
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Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter. 相似文献
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《极地研究(英文版)》2014,(3)
正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprchensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose is to publish achievements in fundamental research,applied 相似文献
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《山地科学学报》2014,(4):I0004-I0009
<正>AIMS AND SCOPE(Editorial Policy)The Journal of Mountain Science(JMS)is devoted to mountains and their surrounding lowlands-ecoregions of particular global importance,with a particular emphasis on the important highlands/mountains in the world,such as the Tibetan Plateau,the Himalayas,the Alps,the Andes,the Rockies and many other mountain ranges of our planet. 相似文献
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《山地科学学报》2014,(4)
<正>The Journal of Mountain Science(JMS),founded in2004,is an international English-language journal on mountain sciences.JMS is supervised by the Chinese Academy of Sciences(CAS),sponsored by the Chengdu Institute of Mountain Hazards and Environment,CAS,published by Science Press China,and distributed by Springer exclusively throughout the world(excluding Mainland China).The JMS is published bimonthly,fulltexted in SpringerLink and CNKI,indexed/abstracted by 相似文献
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Livestock behaviour in the Pyrenees includes free grazing and a long resting period that provokes the accumulation of dung and urine in some places,so-called camping areas. The aims of this study were （i） to analyze any change in floral composition,and in nutritional and chemical contents of plants in a livestock camping area; and （ii） to relate the floral composition with soil chemical properties. In a linear transect,five sampling zones were established,from the centre of the camping area to the surrounding Nardus stricta-dominant pasture. The above ground plant biomass and the topsoil were sampled in each zone with 6 replicates per zone. Plant species were classified and weighed to calculate above ground biomass,nutritional and chemical contents,and Shannon diversity and evenness indices. Additionally,soils were sampled in two periods,at the beginning and at the end of grazing period. Soil available nutrients （nitrate,ammonium,phosphorus,potassium,calcium and magnesium）,total nitrogen,organic carbon and pH were measured.
Plant chemical contents （protein,lignin and others） were significantly related to the proportions of grasses,legumes and other plants; so,the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However,the relationship among plant species richness,diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area,plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers.
Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale,the strong soil nutrien 相似文献
Plant chemical contents （protein,lignin and others） were significantly related to the proportions of grasses,legumes and other plants; so,the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However,the relationship among plant species richness,diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area,plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers.
Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale,the strong soil nutrien 相似文献
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文章概略介绍了利用卫星进行定位的原理 ;由卫星信号传播、信号接收和SA政策等引起的理论误差 ;给出了多种快速、高精度定位的工作模式和观测点选择的原则 ;列出了将WGS - 84坐标转换为我国坐标的公式及解算参数的具体方法 ,供读者在GPS工作中参考。 相似文献