关于供热运行中管网水力工况初调节的几点建议

分析论述了供热运行过程中水力工况失调的原因,提出了在实际运行过程中简单易行的调节方法。     

供暖管网水力失调原因及调节措施

本文论述了供暖管网水力失调的原因及调节措施，提醒设计施工人员避免水力失调造成的运行品质差及能源浪费现象。     

浅议供热管网的结构形式

本文基于既有供热管网的现状,分析了目前枝状管网与环状管网分别存在的问题,提出了对既有供热管网结构进行改造的建议.     

浅谈北方地区供热管网改造整体规划

本文是基于现状供热管网严重老化或供热能力不足所做的管网改造,通过对某北方城市老旧供热管网改造规划的编制,比较直供管网和间供管网的优缺点,分析总结了一系列管网改造的设计原则及技术措施。     

对联片供热实施供暖节能的探讨

作者论述了怎样将分散锅炉房的供热,改造成联片供热,较为集中、较大的锅炉,即能节约能源,又能减少环境污染,是改进供暖条件的好办法,本文介绍了这方面具体的措施。     

高层建筑供暖水系统与外网采取非静压隔绝直接连接的可行性分析

当静压线的高度以一般建筑内低压铸铁散热器的承压能力来确定时,高层建筑空调水系统或高区采暖系统能否与外网采取直接连接方式,且不使用阀前压力调解器与外网进行静压隔绝,而一般建筑内低压铸铁散热器还不超压,以达到节约初投资和方便运行管理的目的。     

关于哈尔滨市群力新区供热管网设计的探讨

本文简要介绍了哈尔滨市群力新区供热管网的连接方式、供回水温度、布置走向、敷设方式、补偿方式、特殊点穿越方案等。     

优化设置热网循环泵

本文通过对热网循环泵工作状态和能耗的分析,指出优化设置热网循环泵应考虑的两项重要技术参数。     

常规木材干燥室不同供热状况的 损失分析

着重分析常规木材干燥室蒸汽管道不同供热状态的损失:当蒸汽管道供热温度一定时,干燥室温度越低,传热温差越大,损失越大;当干燥室温度及蒸汽管道外壁温度一定时,蒸汽管道供热温度越高,传热温差越大,损失越大。传热温差对损失的影响很大,当蒸汽管道供热温度110℃时,传热温差由40℃降到30、20、10℃,其损失分别减少46.08%、77.01%和94.48%,所以要根据干燥室需要的温度尽量减少供热温差,以减少损失。压差流动损失随压差增大而增加,而且压力较高时比压力较低时压降的损失大。蒸汽在管道内压差流动的损失数值比温差传热损失大许多,至少要大1～2个数量级。因此,由锅炉向干燥室供热,应该尽量减少降压节流的情况。     

谈地面辐射采暖方式的应用

本文阐述了地面辐射采暖的特点及辐射采暖的构造,施工方法及注意事项。     

Altered light conditions following thinning affect xylem structure and potential hydraulic conductivity of Norway spruce shoots

Trees must respond to many environmental factors during their development, and light is one of the main stimuli regulating tree growth. Thinning of forest stands by selective tree removal is a common tool in forest management that increases light intensity. However, morphological and anatomical adaptations of individual shoots to the new environmental conditions created by thinning are still poorly understood. In this study, we evaluated shoot morphology (shoot length, needle number, projected leaf area) and anatomy (tracheid lumen area, tracheid number, tracheid dimensions, xylem area, potential hydraulic conductivity) in three Norway spruce (Picea abies/L./Karst.) families exposed to different thinning regimes. We compared shoot characteristics of upper-canopy (i.e. sun-exposed) and lower-canopy (i.e. shaded) current-year shoots in a control plot and a plot thinned to 50 % stand density the previous year. One tree per family was chosen in each treatment, and five shoots were taken per canopy position. We found that upper-canopy shoots in both plots had higher values than lower-canopy shoots for all studied parameters, except lumen roundness and tracheid frequency (i.e. tracheid number per xylem area). Thinning had little effect on shoot morphology and anatomy 1 year after thinning, except for small but significant changes in tracheid dimensions. Needles were more sensitive to altered light conditions, as projected leaf area of shoot, needle number and leaf hydraulic conductivity changed after thinning. Differences between upper- and lower-canopy shoots did not seem to be influenced by thinning and were almost the same in both plots. Our results suggest that lower-canopy shoots require several years to modify their morphology and anatomy to new light conditions following thinning. The slow light adaptation of the lower canopy may be of practical importance in forest management: thinned stands may be predisposed to drought stress because newly exposed shoots experience increased illumination and transpiration after thinning.     

影响外墙面砖脱落的因素及预防措施

本文论述了影响外墙面砖空鼓、脱落的几种因素及预防措施。     

雷竹林覆盖不同发热物质发热规律及对土壤温度的影响

【目的】探索不同发热物质的发热规律,分析雷竹笋用林覆盖中发热物质对土壤温度的影响,为凝练高效低碳雷竹林覆盖模式提供适宜的发热材料和施用方法。【方法】选用生产中广泛使用的3种材料(新鲜鸡粪、枯饼和麦灰)作为发热物质覆盖雷竹林,调查覆盖期内不同时期和不同土层深度的土壤温度,并通过方差分析比较其差异性。【结果】新鲜鸡粪、枯饼和麦灰作为发热物质覆盖雷竹笋用林,土壤温度均在10℃以上,高于未覆盖林地。11月26日覆盖后,前2~5周土壤温度较高,第6周开始温度逐渐下降,第13周(翌年2月底)温度达到最低,之后随着气温的上升,土壤温度又开始上升。不同发热物质的发热规律有所不同,麦灰发热速度快并且集中,前期土壤温度高,增温效果明显,但持续发热时间短,第3周开始土壤温度下降;枯饼发热速度平稳,持续发热时间较长,高温期内土壤温度变化幅度较小;鸡粪发热量相对较低,覆盖初期土壤升温慢,温度较低,但后期土壤温度较高。发热物质和土层厚度均对不同土层的温度差异产生显著影响(P <0.05),覆盖初期发热物质起主导作用,覆盖中期土层厚度起主导作用,覆盖后期共同影响,但二者的交互作用不显著(P> 0.05)。【结论】笋用林覆盖中,不同发热物质的发热规律和发热量不同,鸡粪发热量较小,麦灰持续发热时间短,枯饼发酵分解速度比较平稳,持续发热时间较长,是比较理想的发热物质。生产中可使用枯饼为发热物质,配合适宜的谷壳保温层厚度或采用二次覆盖等措施,实现控制土壤温度和竹笋出土时间,提高笋用林产量和效益的目标。     

绿色采暖—加热电缆的应用

针对当前北方地区冬季采暖存在的“收费难,污染重”的问题进行了分析,提出了“绿色采暖——电采暖”的方式,并把燃煤锅炉、电锅炉和加热电缆的优缺点进行了比较。     

室内采暖系统实现按户计量与温度控制的措施

室内采暖系统按户计量与温度控制的3种措施及其优缺点的探讨。     

Fungal colonisation of outside weathered modified wood

Specimens of Scots pine sapwood (Pinus sylvestris L.) and beech wood (Fagus sylvatica L.) were treated with an amino-alkyl-functional oligomeric siloxane, a sodium water glass solution and 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU). Treated and untreated wood specimens were exposed outdoors without ground contact. After 9?months of outside exposure, all specimens showed discolouration caused by infestations of mould and staining fungi on the exposed wood surface. Fungi grown on the sample surface were isolated and identified by microscopic technique and sequencing of PCR-amplified DNA from the ITS region. Primarily, an infestation by ascomycetes and related deuteromycetes was found. The most dominant fungi were Trichoderma sp. and Epicoccum sp.. An infestation of Aureobasidium pullulans was only detected on untreated and DMDHEU-treated samples. There were only marginal differences of fungal infestation between the two wood species.     

小区外环境的设计

介绍了小区外环境的涵义和小区外环境的特点，初步阐述了小区外环境中心区和街道的设计要素以及设计原则。