绿茶提取液中茶多酚和儿茶素的萃取分离动态模型

应用乙酸乙酯作溶媒 ,从绿茶提取液中萃取茶多酚、儿茶素。采用二次通用旋转组合设计 ,建立了试验因素为 :茶液用量 (X1)、溶媒用量 (X2 )和振摇时间 (X3 )与萃取率 (Y)的数学模型。并对萃取中的动态变化进行了系统分析 ,为利用萃取法分离茶多酚和儿茶素提供了量化基础     

学生身体素质评分方法的实验研究

本文提出了更新学生身体素质评分方法的依据，并根据座标原理将数学评分模型制成了评定学生身体素质成绩的《模型》评分表。实验结果表明：使用《模型》评分表能最大限度地调动不同体能学生课堂学习与课外锻炼的积极性，收到应全面发展体能、不断提高身体素质成绩的实际效果。     

Pasture research in South Africa

The “systems approach” means that decision‐rich parts of any given system are considered quantitatively and in their proper context. This is done by using models of various kinds. A model can be built if an adequate information base exists for the system in question, and if decisions have been taken about the scope and focal point(s) of the model, its application, and its form. The systems approach is illustrated by outlining a general procedure for livestock enterprise planning. Some of the research and extension problems revealed, and new problems created, by this and other models, are mentioned.

Two matters of general concern are discussed. It is argued that the quality of leadership in agricultural research leaves something to be desired. Secondly, the class of agricultural scientists seems to be regrettably indifferent to the long‐term effects of its work, and blind to the needs of primitive food producers. The systems approach can contribute to improvement in both areas, as a result of forcing people to define clear objectives and order their priorities. There is a need for grassland and other research workers to state the objectives of their disciplines for the next 30 years.     

营养水平及性别对生长育肥猪肉质性状发育规律的影响

研究了高低营养水平对长×荣杂交猪肉质性状发育影响。高低营养水平的饲粮消化能分别为 14 2和 12 0MJ/kg ,高营养水平组 2 0～ 5 0kg、5 0～ 80kg和 80～ 10 0kg阶段的饲粮蛋白质含量分别为 18%、15 5 %和 13 2 % ,低营养水平组相应为 15 5 %、13 2 %和 11 2 %。 90头试验猪随机分配到 2个处理中 ,每组 3个重复。当猪的体重分别达到 2 0kg、35kg、5 0kg、80kg和 10 0kg时 ,每重复各取 1头猪进行屠宰 ,测定屠宰性能和猪肉品质。结果表明 ,随着体重的增加 ,背脂厚、眼肌面积、肌间脂肪、失水率、肌肉次黄嘌呤核苷酸和胶原蛋白含量呈二次曲线上升 ,肌纤维面积呈线性上升 ,而瘦肉率和肌肉水分含量呈二次曲线性下降。肉色评分除 2 0kg较低外 ,全期变化不大。营养水平明显影响背脂厚、肌肉水分含量、肌内脂肪含量和失水率 (P <0 0 5或 0 0 1)。与高水平比较 ,低水平明显降低背膘厚、提高肌肉水分含量、降低肌内脂肪含量和失水率 (P <0 0 5 )。营养水平对其他肉质指标无明显影响。性别对肉质指标的影响还需进一步研究     

马尾松天然林采伐年龄的研究

本文对四川蒲江县马尾松天然林采伐年龄进行了研究。试验选定Richard生长模型为马尾松天然林的基本模型，建立了胸径、树高、材积与年龄的生长模型，编制出马尾松生长过程表与林分出材率表，用现行木材价格计算木材收入，采用指率法进行经济分析确定出经济成熟龄。经与实行多年的马尾松天然林采伐年龄相比，其采伐年龄推迟10年左右。     

AMMI模型在油菜品种区域试验中的应用

在油菜品种区域试验中,品种在各地点的表现很不一致,说明品种的基因型（G）和环境（E）存在工作用,常用的GXE交互作用分析法约束性较强,解释G×E交互作用较少。加性立效应和来积交互作用模型（简称AMMI模型）在常规的基因型和环境的加性模型中加入了乘积形式的交互作用,能更多地解释G×E交互作用。本文应用AMMI模型分析1995-1997年度通过四川省油菜区试的品种,结果表明：AMMI模型是具体、直观、灵敏地综合评价油菜品种的一种方法。     

仔猪断奶应激效应定量估测

用动态分析原理,建立了定量估测断奶对仔猪生长应激效应的方法。仔猪早期生长符合指数模型;断奶到断奶应激结束阶段的生长符合二次多项式。两模型的一个交点为断奶应激结束时间;两交点之间积分面积开方值为断奶应激效应值。试验中大约克夏猪28日龄断奶应激效应值为4．52kg;断奶应激结束的时间约为55日龄,即断奶后的27d。     

在茶学研究中正确应用统计分析方法的思考──对《茶树良种苗期生物产量与光合特性的相关研究》等文统计分析的商榷

用逐步回归、通径分析及主成分方法对《茶树良种苗期生物产量与光合特性的 相关研究》一文（表１）数据进行了分析。结果表明，影响茶树生物产量直接的 主要因素是气孔导度（Ｘ３）和单株叶干重（Ｘ６），茶树单株苗干重（Ｙ）的预测回归 方程是 ＝－０．２８６９＋２６．５８４９Ｘ３＋１．９６４７Ｘ６，并且指出对于多元相关变量采用 简单相关分析剔除变量显然是错误的．     

分域模型在细胞代谢动力学中的研究应用

本文综述了分域模型的基本特征及其数学表达。重点阐述了如何用动力学分域成份推测生理学分域结构的方法思路。     

Analysis of factors affecting milk yield of Ankole cows grazed on natural range pastures in Uganda

Effects of seasonal rainfall (RF) and maximum temperature (T_m) variations on milk yield of Ankole cows grazed solely on range pastures were investigated. The resulting changes in herbage growth (HG), herbage yields (HY), herbage crude protein (CP_h) and neutral detergent fibre (NDF_h), as well as body condition score (BCS) of ten milking cows taken every two weeks were analysed for their correlation with milk yield (MY). Results showed that MY was significantly correlated (P = 0.05) with BCS and NDF_h, but not with RF and CP_h. The correlation with T_m, HY and HG were not significant.

Multiple linear regression analysis showed that milk yield increased with body condition and declined with herbage yield according to the model: MY = 3.70?BCS–3.90?HY–6.67. This implied that throughout most of the year, cows depended on mobilisation of body reserves built in the wet season to meet the requirements for milk production. As herbage matured, milk yield declined because cows could not maintain the dietary quality needed for optimal digestion and feed intake. Cows fed to maintain good body condition yielded more milk. Therefore, to minimise maturity, appropriate stocking rates should be applied to maintain young herbage and sustain milk yield.