建筑绝热材料热湿物性参数测试重复性及再现性研究

认识测试误差是建立参数数据库、提高建筑性能模拟工具精度的前提。为了验证相关实验结果的可信度,对EPS、XPS、PUR、发泡水泥四种建筑绝热材料开展了为期一年的防护热板法实验、瞬态平面热源法实验、毛细吸水及真空饱和实验,计算获取了多组热湿物性参数的测试重复性及再现性误差。结果表明,两种导热系数实验及真空饱和实验均具有良好的可重复性,在适当控制下测试本身是值得信赖的;湿物性参数实验误差整体大于导热系数实验误差,尤其是毛细吸水实验;产生误差的主要原因不只是测试原理本身,还包括实验环境控制、仪器设备精度及人员操作细节。

竹炭湿物性测试及其对外墙热湿性能影响的模拟

为探索调湿性竹炭(BC)作为建筑填充材料对建筑构件和围护空间热湿性能的影响,测试了其平衡含水率(u)和蒸汽渗透系数(δ);在WUFI Plus软件中选择3组气候区的6个代表城市,对18组外墙进行了全年热湿性能模拟.湿物性测试结果表明:在测试范围内与3种竹板相比,BC调湿容量在相对湿度为33.4%~85.4%时得到扩大;BC蒸汽渗透系数为9.32×10-11 kg/(m·s·Pa),是竹板的10.0~213.2倍.建筑构造和围护空间热湿性能模拟结果显示:BC对构造填充层含湿量起显著稳定作用,并减小了外墙热湿流量和构件内表面温度振幅;BC有助于减小室内空气温湿度振幅,缩短暖通空调系统(HVAC)开启时间,降低围护空间供暖和制冷量,但对加湿和除湿量影响不明显.

热湿气候地区墙体热湿耦合迁移模型热湿物性参数灵敏度分析

本文将热湿气候地区墙体热湿耦合传递模型中的等温吸放湿曲线斜率、液态水传递系数、水蒸气传递系数、导热系数、比热容作为输入参数,将温度和相对湿度作为输出参数,通过生成Sobol序列对热湿物性参数进行采样,并使用Sobol灵敏度分析法对采样结果进行灵敏度分析,得到热湿物性参数的一阶灵敏度指数和总灵敏度指数,进而分析各热湿物性参数对墙体内温湿度分布的影响程度。结果表明,等温吸放湿曲线斜率和液态水传递系数对墙体内的温湿度分布影响较大,而导热系数和比热容对墙体内的温湿度分布影响较小。因此,在进行墙体热湿耦合模拟时需将等温吸放湿曲线斜率和液态水传递系数视为温度和湿度的函数处理,而水蒸气传递系数、导热系数和比热容可视为常数处理。

木材热湿物性参数测试与比较

由于木结构建筑具有节能减碳的优点,近年来其在世界各地得到大力推广。在木结构建筑的使用过程中,其围护结构构成材料-木材的热湿物理性质参数将显著地影响围护结构的热工性能及霉菌生长情况。因此,准确的物性参数数据能帮助学者科学地进行相关研究与构造优化,进而促进木结构体系的推广。然而,目前国内缺少成体系的相关参数数据库作为支撑。本文参照国内外材料热湿物理性质参数测试标准,对市场上常见的几种木材料进行了实验测试,并与建筑热湿模拟软件WUFI数据库中的相似材料参数进行了对比,总结了材料的热湿物性特征以及不同材料之间的差异。研究结果表明,热湿传递方向与纤维束方向的关系、树木性质的差异、材料的加工工艺以及处理方法等均会对木材的热湿参数造成影响,且这些因素对热湿传递相关性质的影响相比热湿储存性质更为显著。本文测试的参数可为后人的研究与运用提供参考。

墙体裂缝对建筑热湿环境及能耗的影响分析

建筑表面及内部会因为各种原因出现不同程度的损伤,结构的受损则会影响内部温湿度场的分布,对建筑总能耗也会产生影响。通过实验测试了混凝土及抹面胶无裂缝、1 mm和2 mm预制裂缝宽度试件的等效热湿物性参数,并使用WUFI-Plus仿真软件模拟建筑裂缝出现前后沈阳市室内热湿环境及能耗的变化情况。在裂缝密度为9.04×10^(-3)m^(-1)时,房间每月相对湿度增幅最大。墙体裂缝将导致房间的能耗降低,且随着裂缝宽度及裂缝密度的增大,建筑能耗下降幅度增大。

建筑全性能仿真平台用多孔材料湿物性参数测试方法与国际实验室比对分析

建筑材料的湿物理性质是建筑全性能仿真平台分析围护结构热湿过程及建筑热湿环境必不可少的基本参数,其准确性也将直接影响仿真计算最终结果的可靠性。目前,国内外相关研究机构在湿物性测试方法及测试结果等方面仍存在一定差异。为了验证建筑全性能仿真平台用多孔材料湿物性参数的测试方法科学性和测试结果的准确性,提高国际实验室间测试结果的重复性,最终保障仿真平台用基础数据的可比性,课题研究组参与了由比利时荷语鲁汶大学组织的中欧九国湿物性参数测试比对项目,对统一发放的试样进行了真空饱和试验、毛细吸水试验和蒸气渗透试验。测试共分为自选方法测试与规定方法两阶段的测试。比对表明仿真平台用热湿物性数据的测试方法科学,结果具有较好的准确性与重复性。同时也发现,在比对项目第一阶段中真空饱和试验得出的结果最为一致,而蒸气渗透试验产生的偏差最大,其主要原因可能是样品密封和实验湿度控制对实验的影响。

龙胆泻肝汤加减治疗药物性肝炎肝胆湿热证的临床效果分析

目的:研究龙胆泻肝汤加减治疗药物性肝炎肝胆湿热症状的临床治疗效果。方法:此次研究对象为我院收治的86例药物性肝炎肝胆湿热患者,病例选取时间为2016年5月-2017年5月,并将其按照随机的方式分为对照组和观察组,每组各43例。对照组患者使用常规治疗方式治疗,观察组患者在对照组的基础上使用龙胆泻肝汤加减治疗,对比分析两组患者的临床疗效和不良反应发生率。结果:观察组治疗总有效率为95.35%,显效率为79.07%,有效率为16.28%,无效率为4.65%;对照组治疗总有效率为65.12%,显效率为30.24%,有效率为34.88%,无效率为34.88%,观察组总有效率显著高于对照组,观察组1例腹胀,恶心呕吐1例,口苦干1例;对照组4例腹胀,恶心呕吐3例,3例口苦干,观察组的不良反应发生率(6.98%)明显少于对照组(23.26%),两组差异明显,存在统计学意义。结论:药物性肝炎肝胆湿热症状需要通过龙胆泻肝汤加减来进行治疗,而且临床治疗效果良好,患者的病情得到了明显的缓解和康复,值得进一步研究发展。

药物性肝炎肝胆湿热证实施龙胆泻肝汤加减治疗的临床观察

目的:探讨龙胆泻肝汤加减治疗药物性肝炎肝胆湿热证患者的临床效果。方法:收集我院门诊及病房2013年6月-2015年6月收治的60例药物性肝炎肝胆湿热证患者,随机将其分为观察组与对照组,各30例,对照组予常规治疗,观察组在此基础上添加龙胆泻肝汤加减进行治疗,比较两组临床治疗效果及肝功能恢复情况。结果:观察组患者的治疗效果为93.33%,明显优于对照组的76.67%,肝功能各指标改善情况明显优于对照组,两组数据对比差异显著(P<0.05)。结论:采用龙胆泻肝汤加减法治疗药物性肝炎肝胆湿热证能有效提升临床治疗效果,在不同程度上改善患者的肝功能指标,值得临床推广应用。

龙胆泻肝汤加减治疗药物性肝炎肝胆湿热证患者的临床效果观察

目的:总结并研究药物性肝炎肝胆湿热证患者应用龙胆泻肝汤加减治疗的临床效果。方法:研究对象都是在我院2016年7月-2018年1月接受治疗的药物性肝炎肝胆湿热证患者,共44例,以计算机表法实现各组处理。试验组(n=22例)选择龙胆泻肝汤加减治疗,对照组(n=22)进行常规治疗,比较两组患者的临床治疗效果。结果:试验组患者的临床治疗有效率95.45%以及不良反应发生率9.09%均远远优于对照组,呈现出P小于0.05的最终结局,具有探讨研究价值。结论:对药物性肝炎肝胆湿热证患者进行龙胆泻肝汤加减的治疗,具有明显的临床应用效果,可提升患者的临床治疗有效率,降低不良反应的发生情况,改善患者预后,减轻患者病痛。

新型生土材料的调湿性能及导热性

通过热物性参数实验、等温吸放湿实验、反问题法求解导热系数实验研究改性生土材料的热湿物性参数。研究结果表明,改性生土材料的蓄热量大、衰减大、热稳定性强。由等温吸放湿实验得到改性生土材料的等温吸放湿曲线和拟合公式,同时对比平衡湿度曲线,改性生土材料的吸放湿性能优于石膏板、水泥砂浆、混凝土。利用反问题法求解导热系数与温度、含湿量的关系得到相对湿度在 98%时,改性生土材料吸湿平衡后的导热系数比同温度下干燥材料增长了 75. 6%。

湿空气的特性及其对粮食干燥的影响

湿粮食在一定的作业环节中,与干燥介质接触,进行湿热交换的除水过程称为粮食干燥。干燥的目的是使粮食达到加工或存储的标准要求。干燥介质是粮食干燥过程中的热和湿的载体。干燥介质的性质、状态对干燥过程起着决定性作用。当前用于粮食干燥的干燥介质,主要是被加热了的空气。这里所谓的空气,实际上是干空气与水蒸汽的混合物,通称为湿空气。

等温条件下混凝土质扩散系数研究(英文)

混凝土的质扩散系数(Dm)是混凝土材料的一种湿物性,它反映混凝土内部的湿份在空间上趋于均匀的能力。在混凝土温度保持不变的条件下,混凝土质扩散系数取决于材料的微观孔隙结构、初始含湿量的大小及其在空间上分布的均匀性。对同一种混凝土材料而言,混凝土质扩散系数强烈地依赖于混凝土内部的初始含湿率。本文首先从湿度扩散矩的概念上论证了混凝土的质扩散系数与其平均值(Dm)的关系;接着研究平均质扩散系数代替质扩散系数以后,混凝土湿度场的变化趋势;最后讨论了两种不同质扩散系数下混凝土干缩速度、干缩应变、非均匀干缩引起的约束应力等。以北方地区拆模后的大体积混凝土为例,计算了混凝土表面最大干燥应力与干燥深度,其成果可以为混凝土表面保护设计提供参考。

Survey on Bio-resources of Zhengzhou Yellow River Wetland and Protective Measures

Upon the basis of comprehensive survey on the bio-resources of Zhengzhou Yellow River Wetland Nature Reserve,we analyzed the relationship between wetland ecology and bio-resource protection,the problems encountering wetland development and protection,and further put forward corresponding protective measures.

Investigation and Research on Biodiversity of Chen Lake Wetland

Plant diversity, animal diversity and ecosystem diversity in the wetland were studied with field investigation and statistical analysis, and then biodiversity of Chen Lake wetland was also valued. The results showed that the reasonable utilization and protection for biodiversity of Chen Lake wetland gave important contribution to improving the regional environment and sustainable development of Wuhan, and even the middle-lower Yangtze area.

Advances in Research on the Structure and Diversity Variation of Insect Communities in Wetland

The species diversity, structure and dynamic rules of insect communities in wetland can provide data of the insects for the protection, utilization and monitor- ing of wetland, which is an essential link to maintain the healthy ecological system of the wetland and protect the biodiversity in the wetland. A systematic study on the composition and succession of insect communities in the wetland, as well as the indication of insect groups can provide a theoretical basis for wetland protection and management, and thus promote the development of regional economy and en- vironmental protection.

Durability of concrete beams reinforced with CFRP sheet under wet-dry cycles and loading

The test results of eight concrete beams reinforced with carbon fiber reinforced polymer （CFRP） sheets subjected to an aggressive environment under a sustained load are presented. The beams are 1 700 mm long with a rectangular cross-section of 120- mm width and 200-mm depth. The beams are precracked with a four-point flexural load, bonded CFRP sheets, and placed into wet-dry saline water（ NaCl） either in an unstressed state or loaded to about 30% or 60% of the initial ultimate load. The individual and coupled effects of wet-dry saline water and sustained bending stresses on the long term behaviour of concrete beams reinforced with the CFRP are investigated. The test results show that the coupled action of wet-dry saline water and sustained bending stresses appears to significantly affect the load capacity and the failure mode of beam strengthened with CFRP, mainly due to the degradation of the bond between CFRP and concrete. However, the stiffness is not affected by the coupled action of wet-dry cycles and a sustained load.

Study on the Floating Plant Climatic Adaptation of Undercurrent Constructed Wetland in North China

[Objective] The aim was to choose appropriate floating plant in the wetland in the north China.[Method] Pistia stratiotes L.,Eichhornia crassipes,and Hydrocharis dubia（Bl.） Backer were planted in the aquatic biological pool of constructed subsurface flow wetland system in the reservoir.Through filed investigation,the growth of the three kinds of plants was studied and their adaptability to the northern climate was concluded.[Result] Judging from the growth speed and state of the three kinds of floating plants,the biological characteristic of Pistia stratiotes L.can perfectly adapt the environment in the pool in the reservoir,followed by the Eichhornia crassipes.The growth state of the Hydrocharis dubia（Bl.） Backer was the worst one and it can not adapt to the north environment.[Conclusion] It provided references for the choice of artificial floating plant in the north area.

Heterogeneity of Physico-Chemical Properties in Structured Soils and Its Consequences

Structured soils are characterized by the presence of inter- and intra-aggregate pore systems and aggregates, which show varying chemical, physical, and biological properties depending on the aggregate type and land use system. How far these aspects also affect the ion exchange processes and to what extent the interaction between the carbon distribution and kind of organic substances affect the internal soil strength as well as hydraulic properties like wettability are still under discussion. Thus, the objective of this research was to clarify the effect of soil aggregation on physical and chemical properties of structured soils at two scales: homogenized material and single aggregates. Data obtained by sequentially peeling off soil aggregates layers revealed gradients in the chemical composition from the aggregate surface to the aggregate core. In aggregates from long term untreated forest soils we found lower amounts of carbon in the external layer, while in arable soils the differentiation was not pronounced. However, soil aggregates originating from these sites exhibited a higher concentration of microbial activity in the outer aggregate layer and declined towards the interior. Furthermore, soil depth and the vegetation type affected the wettability. Aggregate strength depended on water suction and differences in tillage treatments.

Effect of auxiliary TIG arc on formation and microstructures of aluminum alloy/stainless steel joints made by MIG welding-brazing process

A new hybrid welding process was successfully used to join aluminum alloy and stainless steel. In the MIG welding-brazing process, the lower thermal conductivity of steel can cause dramatic change of temperature gradient on steel surface, while the auxiliary TIG arc can change this phenomenon by heating the steel side. The auxiliary TIG improved the wettability of molten metal, resulting in the molten metal spreading fully on upper surfaces, front and back surface of steel, forming a sound brazing joint; the content of Cr and Ni elements in IMCs layer was increased, which can enhance the quality of the layer; and the microstructure of IMCs layer also was improved, increasing the bonding strength with the weld seam. The average tensile strength of the joint obtained with auxiliary TIG arc（146.7 MPa） was higher than that without auxiliary TIG arc（96.7 MPa）.

Effects of Nitrogen Addition on Plant Functional Traits in Freshwater Wetland of Sanjiang Plain,Northeast China

To clarify the responses of plant functional traits to nitrogen(N) enrichment, we investigated the whole-plant traits(plant height and aboveground biomass), leaf morphological(specific leaf area(SLA) and leaf dry mass content(LDMC)) and chemical traits(leaf N concentration(LNC) and leaf phosphorus(P) concentration(LPC)) of Deyeuxia angustifolia and Glyceria spiculosa following seven consecutive years of N addition at four rates(0 g N/(m2·yr), 6 g N/(m2·yr), 12 g N/(m2·yr) and 24 g N/(m2·yr)) in a freshwater marsh in the Sanjiang Plain, Northeast China. The results showed that, for both D. angustifolia and G. spiculosa, N addition generally increased plant height, leaf, stem and total aboveground biomass, but did not cause changes in SLA and LDMC. Moreover, increased N availability caused an increase in LNC, and did not affect LPC. Thus, N addition decreased leaf C∶N ratio, but caused an increase in leaf N∶P ratio, and did not affect leaf C∶P ratio. Our results suggest that, in the mid-term, elevated N loading does not alter leaf morphological traits, but causes substantial changes in whole-plant traits and leaf chemical traits in temperate freshwater wetlands. These may help to better understand the effects of N enrichment on plant functional traits and thus ecosystem structure and functioning in freshwater wetlands.