毛竹林群落能量结构研究

本文对建瓯市毛竹丰产林的能量结构进行了研究,结果表明,１９９５年建瓯市毛竹丰产林地上部分能量现存量为１１９７７４．８ＫＪ／ｍ２,其中竹叶为７２４９．２ＫＪ／ｍ２（占６．０％）,竹枝为１７４１４．１ＫＪ／ｍ２（占１４．５％）,竹秆为９３９６９．１ＫＪ／ｍ２（占７８．５％）,林下植物为１１５１．４ＫＪ／ｍ２（占１．０％）;地下部分能量现存量为４１８１９．３ＫＪ／ｍ２．毛竹标准样竹的样品中,枝、叶、秆的干重热值分别为１９８７３Ｊ／ｇ、１９４４２Ｊ／ｇ和２００８１Ｊ／ｇ．毛竹林群落地上部分和地下部分能量在垂直分布的配置上分别呈“金字塔型”和“倒金字塔型”的能量结构     

常规索道实用数值表的编制与使用

按无荷中央挠度系数设计索道的方法,在索道承载索张紧度研究的基础上,介绍常规索道实用数值表的编制与使用方法,为索道的优化设计、安装架设和安全检测提供了有力的帮助．     

有关红曲色素的提取及提高其色价的研究

本研究采用液态发酵法来制备用途广泛的天然红曲色素．研究结果表明：ｐＨ值的改变对红曲色素的色调有很大影响,添加ＮａＣｌ和ＣａＣｌ２能有效地提高红曲色素的提取率．另外,本文亦对红曲色素的发酵条件进行了初步的研究．     

中转化糖浆酶法生产工艺研究

以三酶糖化法代替果葡糖浆的双酶糖化法,用果葡糖浆生产设备与工艺路线生产中转化糖浆,同时调整真空过滤真空度。结果表明：每吨干淀粉中ＡＭＧ１５０加入量为４００ｍＬ,ＡＴＧＧ８７４２加入量为６０ｍＬ,Ｆｕｎｇａｍｙｌ１６００加入量为３５ｇ,ｐＨ５．５时,糖化工艺效果最好;真空过滤真空度越低,产品熬温越高。     

Nitrogen fertilization value of compost and dried dung in soils with contrasting synthetic nitrogen fertilization histories

If the production of forage for dairy cattle is to become less reliant on synthetic nitrogen (N) fertilizers, there is need to better understand and account for the N contributed by on-farm and imported organic amendments. A 254-day aerobic soil incubation study (typical length of a growing season in many temperate dairying regions) quantified the inorganic (mineral) N supply from a commercial compost and dried bovine dung (i.e., on-farm effluent solids). Amendments were incubated in soils with contrasting synthetic N fertilization histories (i.e., 70–100 vs. 350–400 kg N/ha per year) to evaluate if higher synthetic N fertilization histories would reduce the lag time that often exists between organic amendment application and significant release of inorganic N for plant uptake. This proposition was based on previous research, which showed greater soil inorganic N availability accelerating organic amendment decomposition. Our experiment did find that the release of inorganic N from evaluated organic amendments was greater in soils with higher synthetic N fertilization histories, but that this effect was not apparent until after the first 6-months of this 9-month experiment. Despite this finding, soils with contrasting synthetic N fertilization histories were not found to differ in their initial inorganic N content, nor microbial activity or other physiochemical properties known to affect N mineralization. Our study highlighted the long-term vision needed when transitioning from synthetic N fertilizers to organic amendments, with most of the N present in the compost and dried dung remaining unavailable for forage production (i.e., remained bound in organic carbon-based molecules).     

抗氧化剂在配合饲料中抗氧化能力的测定研究

饲料抗氧化剂是饲料工业生产中不可缺少的一类添加剂,但对抗氧化剂在配合饲料中抗氧化活性的检测方法的研究很少。实验通过对饲料脂类抽提方法的比较及验证实验,建立了配合饲料过氧化值的检测方法,该方法测定的过氧化值回收率在111%～120%之间。利用此方法对两种不同抗氧化剂在猪配合饲料与膨化大豆中的抗氧化能力进行测定,结果与直接利用油脂得到的数据结果相一致,表明该方法可行。     

中国明对虾WSSV携带量、生长和抗WSSV育种值的相关性分析

为评估中国明对虾生长及抗WSSV能力与中国明对虾WSSV携带量之间的相关性,实验对130个中国明对虾家系进行生长及抗WSSV性能测试,对收集到的中国明对虾生长和抗病数据,输入“水产动物育种分析与管理系统”数据库,利用综合选择指数法估计中国明对虾各个家系的育种值。根据分析结果,选择出生长育种值最大的5个家系和最小的5个家系、抗WSSV育种值最大的5个家系和最小的5个家系,分别检测上述20个家系的亲虾、养殖50 d及170 d中国明对虾的WSSV携带量。结果显示,亲虾、50 d中国明对虾及170 d中国明对虾的WSSV携带量分别为0.190 8、0.286 6和0.232 9 copies/ng DNA,三者之间差异均不显著。亲虾、50 d中国明对虾和170 d中国明对虾的WSSV携带量与中国明对虾的生长育种值相关系数分别为 0.021、0.363和0.185,亲虾、50 d中国明对虾和170 d中国明对虾的WSSV携带量与抗WSSV育种值相关系数分别为0.033、0.048和0.019。研究表明,中国明对虾的生长育种值和抗WSSV育种值与中国明对虾体内的WSSV携带量均无显著的相关性。     

熟制与贮藏对凡纳滨对虾挥发性成分的影响

为研究熟制与贮藏对凡纳滨对虾挥发性成分的影响,采用电子鼻及固相微萃取—气相色谱—质谱联用技术分析虾肉的挥发性成分,并采用相对气味活度值和感官评定法评价虾肉风味的变化。结果显示,熟制与贮藏对虾肉中的挥发性成分影响显著。凡纳滨对虾生虾、熟虾、熟虾冷却、熟虾冷却过夜及二次熟制虾分别被检出50、68、63、49和41种挥发性成分。二次熟制后,虾肉中的挥发性成分有所减少,感官上虾的特征鲜香气也略微减弱;一次熟制对虾肉的风味影响不大。生虾肉中检测出的挥发性成分如壬醛和癸醛等对风味有显著性影响;熟虾肉中检测出壬醛、癸醛和十四醛等;二次熟制的虾肉中检测出对风味影响较大的挥发性成分主要是十八醛、二丁基羟基甲苯等。熟虾经过夜(4°C)放置后,其中检测出的挥发性成分种类和总量均减少,但总量差异不显著。研究表明,熟制可显著增加挥发性风味成分种类和总量,二次熟制与一次熟制相比,凡纳滨对虾的关键风味物质种类和含量显著降低;熟虾冷却后4°C贮藏12 h风味差异不显著。     

证明微分中值定理时构造辅助函数的问题

本文力图通过微分中值定理证明过程中引入辅助函数的几何构思的辨析,帮助读者理解和认识微分中值定理。     

Re-evaluation of total sulphur amino acid requirement and determination of replacement value of cystine for methionine in semi-purified diets of juvenile Nile tilapia, Oreochromis niloticus

Two feeding experiments were conducted to re-evaluate the total sulphur amino acid (TSAA; methionine and cystine) requirement and determine the replacement value of cystine for methionine of juvenile Nile tilapia ( Oreochromis niloticus ). Semi-purified diets used in both experiments contained 3510 kcal gross energy and 280 g of protein per kilogram diet from casein, gelatin and crystalline amino acids. The basal diet of the first experiment contained 3.1 g methionine and 0.4 g cystine per kilogram. l -methionine was added to the seven remaining diets at 1.0 g kg⁻¹ increment to produce methionine levels ranging from 3.1 to 10.1 g kg⁻¹ diet. Each diet was fed to four replicate groups of juvenile Nile tilapia (1.28 g mean weight) in a recirculation system for 8 weeks. Broken-line regression analysis of weight gain data indicated that the TSAA requirement of juvenile Nile tilapia was 8.5 g kg⁻¹ of the diet or 30.4 g kg⁻¹ of dietary protein. In the second experiment, TSAA level was set at 95% of the requirement value determined in the first experiment. Seven diets were made with different ratios of l -methionine and l -cystine (20 : 80, 30 : 70, 40 : 60, 50 : 50, 60 : 40, 70 : 30 and 80 : 20, based on an equimolar sulphur basis). Each diet was also fed to four replicate groups of juvenile Nile tilapia (4.14 g mean weight) in a recirculation system for 8 weeks. Regression analysis of weight gain data using broken-line model indicated that cystine (on a molar sulphur basis) could replace up to 49% of methionine requirement in semi-purified diets for juvenile Nile tilapia.