Logistic方程在微生物分批培养动力学中的应用

将生态学领域中的Iogistic方程引入微生物动力学的研究中，建立了3个分别基于Monod方程、Herbert方程和Logistic方程的关于培养基中的微生物浓度(χ)和底物浓度(s)的模型以形成对照．同时建立了基于Logistic方程的关于微生物浓度(χ)和时间(t)的模型．这些均采用实验数据拟合以证明其精确性．该工作有助于研究微生物生长特性，同时有助于进一步地研究可生化降解的有机物在水体的微生物作用下的氧化分解过程，建立新的河流、湖泊、水库等生物学水质模型．本研究中采用的数值方法是非线性最小二乘法、Interior-reflective Newton算法．在Lorynebacterium glutamicum分批培养和Pseudomonas sp．分批培养中，基于Logistic方程的χ-s模型拟合的相关系数分别是0.9940和0．9867，在Pseudomonas sp．分批培养中，z-t模型拟合的相关系数是0．9972。     

改可变容差法为给定容差法

给定容差法是相对于可变容差法提出的。用给定容差法求解有约束的非线性规划问题,计算时间减少到可变容差法的1/5～1/4。利用给定容差法己在APPLE-Ⅱ微型计算机上求解过20个独立变量、40个约束方程的非线性规划问题。此法可在微型机上推广应用。     

东北过伐林椴树生长过程与生长模型的研究

利用吉林省汪清县金沟岭林场收集的38株过伐林椴树解析木资料,研究椴树年龄与树高、胸径、材积之间的相关关系,分别拟合椴树最优树高-年龄、胸径-年龄、材积-年龄的生长方程,经检验达到精度要求,为预测该地区椴树树高、胸径、蓄积的生长提供理论依据。     

Application of a modified rate equation to the acetylation of wood

A modified rate equation, in which the diffusion of reagent was taken into consideration, was proposed and applied to results reported previously for the acetylation of wood. The equation was fitted more successfully to the prolonged as well as the early stage of the reaction than a common first-order rate equation. Although the conclusions were virtually unchanged, the reliability was enhanced because reaction parameters such as the rate constant, ultimate extent of the reaction, and activation energy calculated for the modified equation were based on much more data than those reported previously. The equation proposed here may be applicable not only to acetylation but to other chemical modifications of cellulosic materials in heterogeneous systems.     

Allometric model of the Reineke equation for Japanese cypress (<Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis>) and red pine (<Emphasis Type="Italic">Pinus densiflora</Emphasis>) stands

An allometric model that explains the mechanism of the difference in the slope of the Reineke equation (A) among species was proposed based on the allometric relationships of mean tree height (H) to quadratic mean diameter D (H ∝ D ^θ ) and stand density N (H ∝ N ^δ ), i.e., A = θ/δ. The proposed model was fitted to Japanese cypress (Chamaecyparis obtusa Endl.) and red pine (Pinus densiflora) stands. The allometric exponents θ and δ were, respectively, 0.8995 and −0.5000 for cypress and 0.8612 and −0.6619 for pine. The difference between cypress and pine was significant for δ but not for θ. Inserting the exponents into the model resulted in predicted slopes of −1.7991 for cypress and −1.3011 for pine. The difference in the slope of the Reineke equation between the two species was produced by characteristics related to the tree crown, rather than characteristics related to stem slenderness. The proposed model enables us to estimate the slope of the Reineke equation from commonly measured stand attributes, such as mean tree height and quadratic mean diameter. Therefore, the proposed model is expected to be practical and convenient for estimating the slope of the Reineke equation and for explaining the mechanism of its variation among species. The model should be also accepted as a generalized model of the stand density versus quadratic mean diameter relationship, whereas the original Reineke equation should be seen as a specific case of this model.     

尾叶桉材积蓄积计算公式初探

从雷州林业局几个点收集２～１１年生的尾叶桉生长资料和４９株解析木材料，用数学回归方程推导出二元材积公式和蓄积公式，经验证，其精确度可靠     

单株平衡法的建立

单株平衡法的建立孙长忠，黄宝龙（西北林学院林学系杨陵７１２１００）（南京林业大学南京２１００３７）关键词黄土高原，蒸腾量，蒸发量，单株平衡法，单株平衡方程，蒸发偏量在黄土高原地区，水分因素对植物生长及生存具有强烈的限制作用。研究植物生长与环境水分条件...     

Numerical experiments of watershed-scale soil water movement and bedrock infiltration using a physical three-dimensional simulation model

Numerical experiments of soil water movement and bedrock infiltration based on a simplified simulation method were conducted to analyze watershed-scale rainfall-runoff processes. To verify the model accuracy, it was applied to a Minamitani watershed (0.45 ha). The simulation was performed with 2.5-m space grids horizontally and five cells vertically. Results of long-term calculation of this model proved that this simulation model is robust and demonstrated good computational water mass conservation. Calculation results showed the best agreement with observed hydrographs and the number of groundwater levels simultaneously when laboratory-tested soil hydraulic characteristics for topsoil were used and infiltration into bedrock was included in numerical calculations. Numerical experiments show that bedrock infiltration generated a stable base flow and suppressed the secondary discharge peak. The reproducibility achieved by observed soil hydraulic characteristics with the assumption of bedrock flow demonstrates the effectiveness of the simulation model used in this article for analyses of watershed-scale soil water movements.     

L35等杨树新品种造林当年年生长节律研究

利用Logistic方程对4个黑杨派杨树无性系的1a生林木的树高、胸径的年生长节律进行拟合。结果表明：利用Logistic方程拟合效果显著，相关系数皆在0．90以上。并以此将各无性系的年生长过程分为成活期、生长前期、速生期和生长后期4个时期，年生长量在后3个时期表现出明显的“慢—快—慢”的节律，其中速生期内的树高生长量占总生长量的比率平均为66．4％，胸径生长量占总生长量的比率平均为64．0％。树高比胸径进入速生期早且结束晚，速生期持续时间长。对各个生长时期林木的生长特点进行了分析，探讨了林木的年生长规律，为加强林木生产管理、提高林地的生产力，提供了理论依据。     

Richards林木生长模型及其适用性

该文简述了Ｒｉｃｈａｒｄｓ生长方程的可塑性，以毛白杨、华北落叶松、刺槐与斑克松的生长资料，讨论了描述林木生长过程的适用性。