检索结果-南通市图书馆

A Study on the Structure and Behavior of Sinter-free Material for Phosphorous Removal from Waste Water

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2010年第11期29卷 1717-1723页

作者：涂云鑫颜俊瑜杨香灵黄守松吴任平于岩 College of Materials science and Engineering at New Campus Fuzhou University Contraction Project Test Center Jianshe Building

Oyster shell and cement were taken as the major raw materials to fabricate hollow, tubular and recoverable material for phosphorous removal （P removal） from waste water without sintering. In this paper, the effects of different affecting factors on the sample P removal ratio were discussed to select optimal P removal process conditions. SEM and XRD were used to characterize the microscopic structures and composition of samples, and molybdenum blue spectrophotometry was applied to determine the P content in waste water. Results showed that at 30 ℃ for 2 d, the P removal ratio reached 93.3% when the cement content was 10 wt% and oyster shell powder was 90 wt%. SEM analysis revealed a flaky structure consisting of phosphorus-containing compound in the samples after P removal, and it piled on and maintained the porous structure. In addition, the results also suggested that raising the ambient temperature was benefit to the P removal. The P removal ratio of the material was optimal under neutral and alkali conditions.

关键词： cement oyster shell phosphorous removal from waste water sinter-free

Effect of Functional Chemical Admixtures on the Performance of Cement Asphalt Mortar Used in Ballastless Track

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials science) 2015年第5期30卷 995-1000页

作者：蒋金洋 SHE Wei LI Wei PAN Li Jiangsu Key Laboratory for Construction Materials Southeast University Jiangsu Institute of building science Co.LTD

Chemical admixtures are of paramount importance to the performance of modern cement based composites. In this paper, we performed a series of tests to investigate the effects of chemical admixtures on the cement asphalt mortar(CA mortar), i e, compressive strength, frost resistance, permeability, fatigue resistance, pore structure and microstructure. In particular, two types of chemical admixtures were tested, i e, defoamer(tributyl phosphate(TBP)) and polycarboxylate superplasticizer(PS). The results indicate that the addition of TBP and PS eliminates big bubbles and promotes small non-connected pores forming in matrix. Besides, an optimum dosage of TBP and PS may be determined with respect to the frost resistance, permeability and fatigue resistance of CA mortar. Further elaborative discussions are presented as well as experimental evidences from mercury intrusion porosimetry, scanning electron microscopy and energy dispersive spectroscopy.

关键词： cement asphalt mortar chemical admixture frost resistance fatigue resistance pore structure microstructure

Effect of Y2O3, CeO2 on Sintering Properties of Si3N4 Ceramics

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2003年第3期21卷 357-359+299页

作者：苏盛彪包亦望王黎李竟先 South China University of science and Technology Beijing 100024 China Guangzhou 510641 China building Material Academy Department of Materials science Key Laboratory for Advanced Ceramics

The effect of rare earth oxides Y 2O 3 or CeO 2 on sintering properties of Si 3N 4 ceramics was studied and the mechanism of assisting action during sintering was analyzed. The results indicate that the best sintering properties appear in Si 3N 4 ceramics with 5% Y 2O 3 or 8% CeO 2. Secondary crystallites are formed at grain boundaries after heat treatment, which decreases the amount of glass phase and contributes to the improvement of high temperature mechanical properties of silicon nitride.

关键词： additive Si 3N 4 ceramics sintering properties rare earths

Distribution characteristics of indoor oxygen concentration under natural ventilation in oxygen-enriched buildings at high altitudes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

building Simulation 2021年第6期14卷 1823-1841页

作者： Cong Song Tingting Zhao Yanfeng Liu Dengjia Wang State Key Laboratory of Green building in Western China Xi'an University of Architecture and TechnologyXi'anShaanxi 710055China School of building Services science and Engineering Xi'an University of Architecture and TechnologyXi'anShaanxi 710055China

Diffuse oxygen supply is an important means to improve the indoor oxygen environment of buildings and ensure physiological and psychological health of immigrants in plateau *** research on oxygen enrichment strategies at high altitudes has mainly focused on confined spaces under mechanical ventilation,with few studies on the distribution of indoor oxygen concentration under natural ventilation in actual *** study used a verified computational fluid dynamics(CFD)method to investigate the indoor oxygen distribution with practical consideration of natural ventilation at high *** results showed that the oxygen distribution under wind-driven natural ventilation was more nonuniform than that under buoyancy-driven natural ventilation,with the ratio of local oxygen concentration to overall-mean oxygen concentration,the k value,between 0.8 and 1.3 under wind-driven natural ventilation and between 0.9 and 1.1 under buoyancy-driven natural *** effects of meteorological condition and oxygen source position on indoor spatial oxygen distribution characteristics were explored with careful examination in human occupied zone under lying,sitting and standing *** results can provide implications for effective and energy saving design of indoor oxygen supply system in plateau buildings.

关键词： high altitude indoor environment-oxygen concentration distribution natural ventilation oxygen enrichment

Effects of mask wearing duration and relative humidity on thermal perception in the summer outdoor built environment

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

building Simulation 2023年第9期16卷 1601-1616页

作者： Rong Hu Jianlin Liu Yongxin Xie Jiao Jiao Zhaosong Fang Borong Lin College of Environmental science and Engineering Donghua UniversityShanghaiChina Department of building science School of ArchitectureTsinghua UniversityBeijingChina School of Civil Engineering Guangzhou UniversityGuangzhouChina Department of building Environment and Energy Engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina

During the pandemic,face masks are one of the most significant self-protection necessities,but they also cause heat *** using the ERA5(ECMWF Reanalysis 5th Generation)database and the local weather bureau data,the effect of mask wearing on outdoor thermal sensation has been investigated by a survey conducted in the hot summer and cold winter region of eastern China in the summer of *** show that wearing a face mask for a longer period result in a higher level of discomfort,and the primary source of discomfort is hot and stuffy *** effect of relative humidity is crucial for mask wearers in warm-biased thermal environments,as mean thermal sensation vote(TSV)peaks when environmental relative humidity reaches the range of 70%to 80%and decreases after this range due to the evaporation within the microclimate created by a face ***,prolonged mask wearing increases participants’hot feelings,especially in warm ***,participants wearing face masks for less than 30 min feel hot at a physiological equivalent temperature(PET)value of 34.4℃,but those who wear them for over 60 min express hot feelings even at a PET value of 24.7℃.The participants who wear a face mask while walking slowly outdoors have similar thermal sensations to those who do not wear a mask,but are in a higher activity *** findings demonstrate that mask wearing has a crucial impact on outdoor thermal comfort assessment in a warm-biased outdoor thermal environment.

关键词： outdoor thermal comfort disposable medical masks mask wearing duration relative humidity physiological equivalent temperature(PET)

Assessment of Curing Efficiency and Effect of Moist Curing on Performance of Fly Ash Concrete

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials science) 2011年第2期26卷 361-366页

作者：李美利钱觉时 College of Material science and Engineering Chongqing University Henan building Research Institute Co. Ltd.

This study was conducted to evaluate the sensitivity of compressive strength,water permeability and electrical resistance of near-surface layer concrete with different fly ash contents to curing *** is shown that the sensitivity to curing condition and fly ash content descends in the following order：difference between internal and surface resistivity （ρ） at 28 days,water permeability and compressive strength;both of longer duration of moist curing and use of fly ash in concrete enhanced the water penetration *** is indicated that the resistivity difference ρ at 28 days can reflect accurately the curing history of fly ash concrete regardless of mix proportions;and use of fly ash in concrete requires longer moist curing duration.

关键词： concrete fly ash compressive strength water permeability resistivity

Modelling of finger-like channelled anode support for SOFCs application

在线全文

学校读者我要写书评

暂无评论

science Bulletin 2016年第17期61卷 1324-1332页

作者： Bin Chen Haoran Xu Meng Ni building Energy Research Group Department of Building and Real EstateThe Hong Kong Polytechnic University

This paper established a numerical model for a solid oxide fuel cell （SOFC） button cell, focusing on the effects of finger-like channels on the gas transport process in the anode support. The current densities of channelled button cell and un-channelled button cell are compared at different operating temperature and voltage with H2 as the fuel. The H2 transport is discussed in detail, such as the mole fraction distribution of H2 in the porous layer, the diffusion flux and convective flux of Ha. It is found that the performance of SOFC can be improved by 2.60 % at 800 ~C, 0.5 V, com- pared with un-channelled SOFC due to the improved gas transport by the finger-like channels. Then, the model is further extended to study 2D-planar SOFC fuelled with syngas. The mole fraction gradients of H2, CO, CH4 and CO are all substantially reduced by the finger-like channels compared to un-channelled planar cell. It is found that the SOFC performance is improved by 5.93 % at 800℃, 0.5 V, when syngas fuel is used. The present study clearly demonstrated that the use of finger-like channels in the anode support is effective in improving the gas transport and the SOFC performance. The present model can be employed for subsequent optimization of the channel configuration for further performance improvement.

关键词： Phase inversion CFD modelling Finger-like channels Concentration loss

A direct measurement method of quantum relaxation time

在线全文

学校读者我要写书评

暂无评论

National science Review 2021年第4期8卷 91-99页

作者： Peng Zhang Haoqi Tang Chuanchuan Gu Hong Wang Guangfu Luo Yalin Lu X.-D.Xiang Department of Materials science and Engineering & Department of Physics Southern University of Science and Technology Synergetic Innovation Center of Quantum Information and Quantum Physics & Hefei National Laboratory for Physical sciences at Microscale University of Science and Technology of China Materials Genome Initiative Center and School of Materials science and Engineering Shanghai Jiao Tong University State Key Laboratory of Green building Materials China Building Materials Academy Guangdong Provincial Key Laboratory of Computational science and Material Design Southern University of Science and Technology

The quantum relaxation time of electrons in condensed matters is an important physical property, but its direct measurement has been elusive for a century. Here, we report a breakthrough that allows direct determination of quantum relaxation time at zero and non-zero frequencies using optical *** dielectric loss function, we connect bound electron effects to the physical parameters of plasma resonance and find an extra term of quantum relaxation time from inelastic scattering between bound electrons and conduction electrons at non-zero frequencies. We demonstrate here that the frequency-dependent inelastic polarization effect of bound electrons is the dominant contribution to quantum relaxation time of conduction electrons at optical frequencies, and the elastic polarization effect of bound electrons also dramatically changes the plasma resonance frequency through effective screening to charge carriers.

关键词： quantum relaxation time plasma resonance dielectric loss function

Isothermal Adsorption Characteristics and Kinetics of Cr Ions onto Ettringite

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials science) 2019年第3期34卷 587-595页

作者： WANG Xin CUI Suping School of Materials science and Engineering Beijing University of TechnologyBeijing100124China China building Materials Academy State Key Laboratory of Green Building MaterialsBeijing100024China

The isothermal absorption properties and kinetic model of Cr(VI) and Cr(III) onto ettringite were investigated using the batch adsorption method. IR analysis was used to study the difference and mechanism of the adsorption of chromium ions with different valence states. The results show that the adsorption of Cr(III) onto ettringite at 20 ℃ agrees with Langmuir’s isothermal model. The ion binding stability was significantly greater than that of Cr(VI). While the adsorption of Cr(VI) onto ettringite agrees with Freundlich’s isothermal model, the D-R model fits the adsorption isotherms of two types of valence Cr(R2>0.994). It can be concluded that the adsorption of Cr(III) onto ettringite is mainly by chemical adsorption and that the adsorption of Cr(VI) onto ettringite is mainly by physical adsorption. Dynamic model fitting and model parameter analyses show that the adsorption of Cr(III) onto ettringite agrees with the pseudo second order kinetics model given by Lagergren. The formation of chemical bonds is the main factor causing the fast adsorption. Cr(VI) adsorption is mainly dominated by liquid film diffusion, and the adsorption rate is much slower than that of Cr(III) adsorption.

关键词： ettringite Cr adsorption kinetics mechanism