中心驱动式木材抓具优化设计研究

给出了中心驱动式木材抓具有两种不同工作状态下的抓取力计算公式，对中心驱动式木材折旧抓具的优化设计作了深入的研究和探讨，编制了优化设计程序，取得了一些具有实际使用价值的结论。     

双联圆锯径切板优化下锯研究

面对我国森林资源不足、质量不高的状况,研究和应用优化下锯理论实现原木最优下锯,提高木材出材率已成为缓解木材供需矛盾的重要途径之一。本文提出了以最优化技术为基础的原木优化下锯法,以最小余料为目标函数的原木优化下锯方法,采用解析法建立原木优化下锯数学模型,通过计算机辅助排样求解,得出了一种基于梯形下锯法锯切原木的优化下锯算法,为数控双联圆锯径切板优化下锯提供了数学方法和基础,并给出应用实例。     

响应曲面法在刨花板制造中的应用

笔者应用响应曲面法建立目标参数模型,对不同工艺条件下的刨花板制造的模型进行了详细分析和讨论。并得出刨花板性能指标的相应分析模型和实验室条件下的优化工艺参数。结果表明:最优工艺条件为含水率达到A=14.7%;施胶量B=18.09%;热压温度C=155.78℃。实测内结合强度为1.09MPa,静曲强度为18.28MPa,吸水厚度膨胀率为4.82%。试验结果均符合国标指定要求,响应面法模型拟合效果较好。     

Economic Analyses of Rubber and Tea Plantations and Rubber-tea Intercropping in Hainan, China

This study uses land expectation value (LEV) as a criterion to conduct economic analyses of natural rubber (Hevea brasiliensis) and tea (Camellia sinensis var. assamica) monoculture, and rubber-tea intercropping. We calculated LEV by using the Faustmann model that combines annual revenue flow from latex production with final timber harvest of rubber trees. Production and cost data were collected from Xinwei Farm in Hainan, China. We found that rubber-tea intercropping generated higher LEV than rubber and tea monoculture under current socio-economic circumstances. Sensitivity analysis has been conducted to examine the impacts on land expectation value by interest rate, prices of natural rubber and tea, and labor costs.     

森林旅游中非生态旅游行为及行为守则研究

通过分析森林旅游中旅游者、旅游管理者和政府的许多非生态旅游行为和这些行为对自然环境及旅游行为本身的影响 ,提出了三者的生态行为守则框架 ,旨在为制订森林旅游区生态旅游管理办法提供借鉴。     

Optimal management of uneven-aged Norway spruce stands

An optimization model is specified to analyze forest management without any restrictions on the forest management system. The data on forest growth comes from unique field experiments and is used to estimate a nonlinear transition matrix or size-structured model for Norway spruce. The objective function includes detailed harvesting cost specifications and the optimization problem is solved in its most general dynamic form. In optimal uneven-aged management, stand density is shown to be dominated by limitations in natural regeneration. If the goal is volume maximization, even-aged management with artificial regeneration (and thinnings from above) is superior to uneven-aged management. After including regeneration and harvesting costs, the interest rate, and the price differential between saw timber and pulpwood, uneven-aged management becomes superior to even-aged management. However, in the short term the superiority is conditional on the initial stand state.     

二仙岩亚高山泥炭藓沼泽湿地兽类资源调查

2006年9~10月对湖北省咸丰县二仙岩亚高山泥炭藓沼泽湿地的兽类进行了调查,记录到兽类43种,隶属8目19科。该湿地兽类属东洋界的有33种,占76.74%;属古北界的有4种,占9.30%;广布种6种,占13.96%。国家I级重点保护兽类2种,国家Ⅱ级重点保护兽类9种。被列入《濒危野生动植物种国际贸易公约》的兽类15种(附录Ⅰ5种、附录Ⅱ4种、附录Ⅲ6种),被列入《中国濒危动物红皮书》的兽类有12种(濒危物种2种、稀有种1种、易危物种9种)。分析兽类的生态类群,最后对兽类资源的保护提出了建议。     

云南板栗良种化途径探讨

云南板栗因长期实生繁殖，良莠不齐，至今尚无主栽品种。良种问题已成为限制云南发展板栗生产的主要因素。实现板栗良种化的主要途径是以实生选种为主，引种为辅；建立高接采穗圃，大力推广优良无性系品种。     

Selection of roosting habitats by Nyctalus noctula and Nyctalus leisleri in Białowieża Forest—Adaptive response to forest management?

Tree dwelling bats select cavities in large, old, dying or dead trees. This inevitably brings them into direct conflict with the interests of forest managers, who are trained to fell such trees. Therefore the identification of forest stands providing optimal roosting opportunities for bats is crucial, in order to provide appropriate guidelines for forest management. It is also important to identify the extent to which the roosting ecology of bats changes in response to habitat modification. Bia?owie?a Forest (BF) offers a unique opportunity, in the temperate zone, to observe differences between areas with no direct human intervention and managed areas and in particular to reveal the effect of forest management on the roosting ecology of forest dwelling bat species. We used GIS techniques to evaluate bats’ spatial response to changes in forest structure and to test the hypotheses that the forest dwelling bats Nyctalus noctula and Nyctalus leisleri prefer roost sites within old deciduous or wet woodlands over young and coniferous ones and that roost site preferences reflect the extent to which dead and dying trees are removed. There was a significant difference in the selection of roosting habitat between the managed and pristine areas of the forest. Within the pristine forest, both species displayed a strong preference for roost trees located within old deciduous stands (>100 years), whereas in the managed part of the forest old wet woodland was preferred while all medium and young forest stands were avoided. Our data reveal a high degree of lability in the selection of roosting habitat by bats. It appears that bats are able to respond to changes in their environment by changing their roost site preferences and could therefore occupy habitat previously considered less suitable.     

Feeding patterns of Indian giant flying squirrel(Petaurista philippensis,Elliot 1839) with reference to seasonal variation in central Gujarat,India

Indian Giant Flying Squirrel(Petaurista philippensis Elliot 1839)is widely distributed in South Asia and the only species of flying squirrel found in Gujarat.We studied the seasonal variation in its feeding behaviour at selected sites of Central Gujarat.Focal sampling was employed to study the behaviours and mainly feeding behaviours.Feeding analyses were consistent with other studies and indicated Madhuca longifolia as an important food resource.The diet of the species mainly consisted of pith,twig,seed,bark,petiole,young to mature leaves,flower and fruits of 20 species of plants of 15 families along with lichens,Vanda tessellata and Dendrophthoe falcata.Madhuca longifolia(25%)contributed most to the squirrel diet,followed by Diospyros melanoxylon(10%)and Terminalia tomentosa(9%).Among the plant parts consumed,pith formed the highest bulk as a food at 23%,followed by fruits(21%),bark(16%),twig(14%),flower(10%),seed(6%),leaf(6%),and bud(4%).The findings reveal the high dependency of flying squirrel on certain tree species.These tree species are well represented and distributed throughout central Gujarat,indicating that this area is important for the survival of this species and that the area should be conserved for protection and future management of this species.     

Economics of Forest Thinnings and Rotation Periods for Finnish Conifer Cultures

In this study simultaneous optimization of thinnings and clear-cutting was investigated. The density-dependent whole-stand model was specified for all relevant Finnish Norway spruce (Picea abies (L.) Karst.] and Scots pine (Pinus sylvestris L.) site indices and solved by non-linear programming. Sensitivity analysis showed that in some cases and owing to endogenous thinnings the optimal rotation length may increase with the rate of interest and site fertility, and decrease with harvesting cost. The number of thinnings is more sensitive to changes in the rate of interest, logging conditions and site productivity for Scots pine stands than for Norway spruce stands. Economic optimization suggests that for both species the first thinning should be performed later than officially recommended. The last thinning should be heavier than officially recommended, especially at high rates of interest. This increases the optimal rotation length compared with solutions under restricted thinning intensity.     

苏云金杆菌CF1263菌株发酵条件优化的研究

对高毒BT菌株——CF1263进行液体振荡培养和正交试验结果表明:依据碳源、氮源和无机盐对芽孢产量的影响,对液体培养基进行成分优化组合,在碳源和氮源中分别筛选出最佳因子,淀粉、蛋白胨、牛肉膏、麦麸、酵母粉,从无机盐中筛选出KH2PO4和MgSO4.7H2O。运用以上7个因素进行L18(37)因素3水平的正交试验,从而得出CF1263最优配方为1.5%淀粉、2%蛋白胨、0.2%牛肉膏、0.3%麦麸、2.0%酵母粉、0.1%KH2PO4和0.2%Mg-SO4.7H2O。     

运输问题最优方案探讨

运用两种方法即最小元素法和最大最小元素法。求运输问题的最优方案。最小元素法编制初始方案只考虑运价:最大最小元素法编制初始方案既考虑运价,又同时考虑了供求量。两种方法编制初始方案出发点不同,通过调整、改进,最终得到的使总运费最少的最优方案就不一样。因此,运输问题最优方案不是唯一的。     

Determination of optimal rotation period under stochastic wood and carbon prices

The valuation of forest stands is traditionally based on a profit calculus involving revenue from wood sales and associated costs. Currently, the role of carbon management in forests is actively discussed. In a stochastic setting we extend the analysis of the optimal rotation period by considering uncertain revenue streams from carbon trading. We develop a real options model given uncertainties in future wood and CO₂ price behaviour. A detailed sensitivity analysis of the numerical results for both cases – with and without carbon sequestration – is provided. We find that optimal rotation periods vary considerably with (i) the type of price process, (ii) the way how carbon income is defined, and (iii) the selection of discount rates.     

杨树灰斑病优化管理技术的研究

本研究以杨树－杨树灰斑病生态系统为研究对象,在杨对生长模型和杨树灰斑病流行模型的基础上,建立了杨树灰斑病危害的损失量模型和多维动态经济阈值模型。模拟了杨树－杨树灰斑病的系统动态,并根据杨树灰斑病常用的管理措施,结合经济核算确定不同条件组合下的经济阈值,建立了杨树灰斑病的优化管理决策系统。     

运材汽车最佳更新期确定方法的探讨

探讨了运材汽车最佳更新期确定的两种方法：低劣化数值法和边际效益法，可供木材运输企业（个人）在决策时参考。并指出了影响运材汽车最佳更新期确定的主要因素：汽车型号、生产条件、管理水平、年运输周转量等。     

新昌小将林场兽类初步研究

１９９６年４－５月，地新昌县小将林场的兽类进行了调查，计算兽类３１种，隶属６目１３科，其中东洋界种２４种，占７７．４２％；古北界种７种，占２２．５８％，分析了啮齿类的种类、捕获率、生态分布、性比及数量变动趋势，对啮齿类群落的多样性和生物量进行了测定，对林木鼠害的发生进行预测。     

蓝莓果渣中熊果苷提取工艺的研究

以蓝莓果渣为原料,研究熊果苷的适宜提取条件。试验采用超声波辅助提取法从蓝莓果渣中提取熊果苷,采用正交试验确定适宜的提取工艺条件。试验结果表明,熊果苷提取的适宜工艺条件是乙醇浓度60%,料液比1∶20g/mL,超声时间40min,超声功率400W,在此条件下,熊果苷提取效果较好。     

广州花园酒店空间改造与优化设计研究

在城市化进程快速发展的同时,一批城市高档酒店迅速崛起,导致城市早期建成的知名酒店因更新步伐较慢,而逐渐失去竞争力。因此建设时间较早、已明显老化的酒店迎来了更急迫的发展挑战。如何优化酒店原有的生态价值和人居环境,提升酒店的服务体验与综合发展成为重要的研究课题。以广州花园酒店为例,利用“道法自然”“以人为本”的设计思想,从优化酒店公共空间序列、完善景观层次、丰富植物种类及色彩、提升景观群落韵律等方面,提出酒店景观空间的优化、改造与再利用措施,力求提升酒店的竞争力。     

基于环境影响的公路路线方案优选

本文综合分析了公路建设中与公路选线相关的环境影响问题 ,在此基础上构建了基于环境影响的公路路线方案评价指标体系 ,并探讨了用于路线方案综合评价的数学模型。