房屋增层改造技术探讨

就房屋增层改造的原则、方法和增层要注意的要点进行了详细的阐述。     

饱和粘性土上房屋增层改造的地基评价

旧有建筑的增层改造,首先要重新评价地基现有的承载能力。本文运用固结理论推导出饱和粘性土地基承载力和沉降的简化计算,对工程实践有一定的指导意义。     

建筑物增层的结构设计方案

本文从直接增层方案和外套结构增层方案两方面，论述了建筑物增层的结构设计方案及要求。     

绿讯

呼和浩特市2010年将对27条主干道进行增绿改造2010年,呼和浩特市将对城市核心区二环路景观带、成吉思汗大街、乌兰察布东街等27条主干道及以小黑河河道生态治理为主的4条河道实施增绿改造工程。     

增绿添彩主题下高校校园园林景观优化改造技术研究——以北京农业职业学院为例

通过总结北京农业职业学院增绿添彩主题下校园园林景观优化改造技术研究实践,进一步探索园林景观优化改造技术,提出相应的定位和措施,旨在为首都园林景观优化改造和彩色植物应用提供参考。     

建筑物增层工程勘察方法探讨

为提高建筑物的使用效能、节省土地空间、合理利用有限资金，业主会考虑在原有建筑物基础上进行增层利用，章就建筑物增层工程勘察方法进行探讨。     

某办公楼加层改造的设计

某城镇砖混办公楼由三层加层改造为五层,新加楼层建筑功能和结构形式不变.原工程基础以上经验算不需要加固处理,只需对基础进行托换处理.经使用工程情况良好,设计经验可供参考.由于低层建筑改造为多层建筑能够节约材料,减少占地,节约国家资源,因此加层成为经济有效的建筑改造措施.     

洞头黑松林相改造对群落多样性影响研究

本文研究温州洞头黑松林(Pinus thunbergii Parl.)间隔式带状皆伐补植改造2年后,对群落多样性的影响。结果表明:黑松群落共有维管植物26科30属31种,热带、亚热带区系特征显著;阔叶化改造后物种丰富度得到提高,改造后物种数提高到29种,提高了52.6%,其中灌木种类增加最多;群落多样性指数Simpson和shannon-Wiener分别提高了102.0%和117.5%,各层次的多样性为灌木层>草本层>乔木层,但均匀度上却为草本层>灌木层>乔木层。笔者认为,从景观质量、群落生物多样性和保持水土能力的提高三方面考虑,这种间隔式带状皆伐阔叶化改造方式,可在洞头地区坡度不陡、土层中等以上的针叶纯林改造中大力应用,并可推广到温州其他地区。     

低产毛竹林改造技术的调查研究

对福建省低产毛竹林的改造技术进行调查，结果表明；不同类型的低产毛竹林应采取不同的改造技术措施，深翻改土是残败型毛竹林改造的关键措施；劈山清杂、加强垦复抚育管理和适当增施肥料是荒芜型低产毛竹林改造的重要措施，而调整竹林的年龄结构则是提高低产竹林产量和质量的根本途径。     

近自然化改造对杉木人工林物种多样性的影响

在广西凭祥市热林中心青山实验场设置杉木人工林近自然化改造样地,进行3种间伐强度处理(75%、55%、35%),均匀套种4种阔叶树。改造5年后,研究不同间伐强度近自然经营对群落组成、物种多样性和林分生长状况的影响。结果表明:近自然化改造5年后,乔、灌、草3层的物种数明显增加,灌草层的优势种有所变化,但各间伐处理的优势物种大致相同;各间伐处理的灌木层物种多样性指数无显著差异;改造后各处理草本层物种多样性指数均高于未改造的纯林,各处理草本层的Simpon指数和均匀度指数均显著高于改造前的纯林。杉木胸径随间伐强度的增大而增加且差异显著,但各处理间树高无显著差异;套种的4种阔叶树的胸径、树高随间伐强度的增大而增加,大叶栎、红椎的胸径、树高生长量在不同间伐处理林分中有显著差异;高间伐强度改造的杉木人工林适合套种阳性树种大叶栎、米老排和中性树种红椎,中等间伐强度改造的杉木人工林适合套种耐阴性树种润楠。     

Influence of variable organic matter retention on nutrient availability in a 10-year-old loblolly pine plantation

The effects of varying forest floor and slash retention at time of regeneration were evaluated 10 years after the establishment of a loblolly pine plantation near Millport, Alabama. Treatments included removing, leaving unaltered, or doubling the forest floor and slash material. Forest floor and litterfall mass and nutrient concentrations, available soil N, foliar nutrient concentrations and stand yield were all impacted by the treatments. Forest floor mass and nutrient contents in the doubled treatment were significantly greater than the other two treatments. The doubled treatment accumulated 25, 45 and 350% more forest floor mass and 56, 56, and 310% more N than the control treatment in the Oi, Oe, and Oa layers, respectively. The other nutrients followed similar patterns. Potentially mineralized NO₃⁻-N in the mineral soil was also significantly higher in the doubled treatment. The positive effect of doubling the forest floor on soil N availability was reflected in greater foliage production, 30% more litterfall and 25% more stand yield for this treatment. This study shows that increasing the forest floor retention has resulted in increased nutrient availability and improved tree growth.     

Experimental evaluations of material damping in timber beams of structural dimensions

Understanding the inherent damping mechanisms of floor vibrations has become a matter of increasing importance following the development of new composite floor layouts and increased span. The present study focuses on the evaluation of material damping in timber beam specimens with dimensions that are typical of common timber floor structures. Using the impact test method, 11 solid wood beams and 11 glulam beams made out of Norway Spruce (Picea abies) were subjected to flexural vibrations. The tests involved different spans and orientations. A total of 420 material damping evaluations were performed, and the results are presented as mean values for each configuration along with important statistical indicators to quantify their reliability. The consistency of the experimental method was validated with respect to repeatability and reproducibility. General trends found an increasing damping ratio for higher modes, shorter spans, and edgewise orientations. It is concluded from the results that material damping of timber beams of structural dimensions is governed by shear deformation, which can be expressed more conveniently with respect to the specific mode shape and its derivatives.     

Light availability influences root carbohydrates, and potentially vigor, in white oak advance regeneration

Oaks (Quercus spp.) are experiencing recurring regeneration failures associated with pervasive mid- and under-story strata of shade tolerant species in intact, undisturbed forests. Where oak regeneration occurs, inadequate vertical height and depleted root carbohydrate stores impede the ability of regenerating oaks to respond when light does become available. A variety of silvicultural techniques have been developed to increase the penetration of diffuse light, enhancing the light environment on the forest floor, and thereby increasing the likelihood of regenerating oaks to successfully respond to increased light transmittance. We measured shoot and root characteristics, and root soluble non-structural carbohydrate concentrations of white oak (Q. alba L.) advance regeneration exposed to enhanced light intensities associated with a mid-story removal and a clearcut, and compared white oak regeneration vigor to untreated controls.

Root diameter and soluble non-structural carbohydrates increased with increasing light availability. Our data suggest that white oak responds to increases in light transmittance by building below-ground biomass and carbohydrates in the root system prior to an above-ground response. Our study shows that white oak regeneration vigor increases with only modest increases in light. In the absence of other pressures, enhancing the light environment to the forest floor should contribute to successful regeneration of this species.     

Effective lateral resistance of timber–plywood–timber joints connected with nails

In this study, an experimental study was conducted on the nailed timber–plywood–timber joints extended from the standard wall–floor joints of wooden light frame constructions, where the bottom plates of shear walls are nailed to the floors consisting of joists and floor sheathings nailed to them. The principal conclusions are as follows: The allowable lateral resistance of the nailed timber–plywood–timber joints can roundly be estimated by neglecting the plywood panels if their densities are higher than those of the timber main-members and they are fastened effectively onto the timber main-members. The stiffness of the timber–plywood–timber joints is less than that of the control timber–timber joints, which is improved by increasing the number of nails used to fasten the plywood panels onto the timber main-members. The stiffness of the joints whose floor sheathings are glued onto the joists is equivalent to the control timber–timber joints. The timber–plywood–timber joints with appropriate specifications have greater energy capacity until the failure than that of the control timber–timber joints. This ensures their energy capacity, which is important in dynamic resistance, to be equivalent to the control timber–timber joints.     

Influence of soil organic matter contents on soil water characteristics of forests on east slope of Gongga Mountain

By testing soil organic matter （SOM） contents, soil water contents （SWC） within low suctions, and saturated infiltration rates of samples taken from east slope of Gongga Mountain of China, the enhancive effects of SOM contents on SWC within low suctions and saturated infiltration rates were quantified. The simulated functions might be applied on regional experience forest-hydrology model. The improving function of protecting forest floor and increasing SOM contents on forest ecosystem hydrological effects were also embodied.     

我国木地板产业融资对出口贸易的影响与对策研究

经过多年发展,我国正逐步实现由木地板生产大国向强国转变。目前木地板产业正在朝着集群化发展模式转变,这种转型所需的资金投入较大,基于木地板产业可持续且健康发展的需求,必须要从源头做好融资的有效风险管控。论述了我国木地板产业融资规模、融资特点,分析了我国木地板产业融资对出口贸易产生的影响,提出了强化我国木地板产业融资对策,以期为木地板产业融资提供参考。     

住宅环境景观中的架空层设计——以西城美墅小区架空层景观设计为例

建筑架空层是一种特殊的景观空间。文章以西城美墅小区架空层景观设计为例,分析了架空层与住宅环境景观的关系,探讨了架空层园林的设计要点,指出架空层园林景观的营造是城市园林绿化建设充分利用空间的一个新途径。     

井字型地板自动上料系统关键装置设计

介绍了一种井字形自动上料系统，并对其中的一些关键问题（如翻板装置、推板装置和皮带输送装置设计）进行了较详细的论述，该系统使地板上料过程的自动化程度大大提高，显著提高了生产率。     

美国337调查对我国地板出口的影响及对策研究

美国作为我国地板出口的最大市场,337调查对我国地板出口贸易产生重要影响。分析了我国地板出口遭受美国337调查状况及受调查的原因,阐述了美国337调查对我国地板出口的影响,从政府、行业和企业层面提出了美国337调查背景下促进我国地板出口的对策。     

基于太阳能利用的储能缓释地板模块的研制

为实现对能源的高效利用,研制了一种具有储热与热缓释的功能地板模块,对该地板模块的结构进行了设计,检测分析了5种隔热保温材料的导热系数,并对地板模块的热学特性进行了计算分析。结果表明,用挤塑板做隔热底板的保温材料热损失最少,而热源温度在60～70℃时,地板模块的吸热量最大,因此选择挤塑板做隔热底板的保温材料,地板模块的热源温度为60～70℃。