共查询到20条相似文献，搜索用时 281 毫秒
1.
Wall cracking and mold expanding due to concrete vibrations can be effectively solved through the application of precast normal-concrete composite shear walls infilled with self-compacting concrete (SCC). However, the high liquidity of SCC will induce a higher lateral pressure. Therefore, it is important to obtain a better understanding of the template lateral pressure. In this work, nine composite shear walls were experimentally investigated, focusing on the effects of two parameters, i.e., the casting rate and the section width of the formwork. The time-varying pressure was monitored during the SCC pouring. It is found that the increase of casting rate from 3.2 m/h to 10.3 m/h resulted in a higher maximum lateral pressure. The higher casting rate led to a longer time required for the lateral pressure to drop to a steady value. There was no correlation between the section width and the rate of decrease in the initial formwork pressure and stable value. Based on the test results, a formula considering the effect of casting speed for the calculation of SCC formwork pressure was established to fill the gap in the current standards and for engineering applications. 相似文献
2.
In the hostile and highly corrosive marine environment,advanced composite materials can be used in marine current turbines due to their high strength-to-weight ratios and excellent resistance to corrosion.A composite material marine current turbine(CMMCT),which has significant advantages over traditional designs,has been developed and investigated numerically.A substantial improvement in turbine performance is achieved by placement of a duct to concentrate the energy.Computational fluid dynamics(CFD) results show that the extracted power of a ducted CMMCT can be three to four times the power extracted by a bare turbine of the same turbine area.The results provide an insight into the hydrodynamic design and operation of a CMMCT used to shorten the design period and improve technical performance. 相似文献
3.
XU Gao-xiong 《重庆大学学报(英文版)》2011,10(2):78-83
It is important for the safety of transmission system to accurately calculate single-phase earth fault current distribution. Features of double sided elimination method were illustrated. Quantitative calculation of single-phase earth fault current distribution and case verification were accomplished by using the loop method. Influences of some factors, such as single-phase earth fault location and ground resistance of poles, on short-circuit current distribution were discussed. Results show that: 1) results of the loop method conform to those of double sided elimination method; 2) the fault location hardly influences macro-distribution of short-circuit current. However, current near fault location is evidently influenced; and 3) the short-circuit current distribution is not so sensitive to the ground resistance of poles. 相似文献
4.
计算机及其网络的发展在改变着人们的经济模式和文化观念,同时对英语学习也产生了巨大的影响。计算机辅助语言学习已成为或将要成为一种新的英语学习模式。一、计算机及其网络在语言学习上的应用计算机辅助教学 CAI(Computer Aided Instruction)是计算机非常重要的应用领域之一,其中计算机辅助语言学习 CALL(Computer Assisted Language 相似文献
5.
计算机及其网络的发展在改变着人们的经济模式和文化观念,同时对英语教学也产生了巨大的影响,任何一种传统的英语教学方法都是无法同它相比的.过去的英语教学,除了教师在课堂上使用授语外,虽也借助其它手段,如图片、录音带、录象带等,但效果都不理想,而借助计算机(软件)及其网络进行教学则可大大弥补其不足.计算机辅助语言学习已成为或将要成 相似文献
6.
《韩山师范学院学报》1996,(4)
《五镇的安娜》是本世纪初英国小说家阿诺德·本内特(Arnold Bennett,1867—1931)的“五镇”系列小说之一。书中叙述了女主公安娜·特尔莱特在与亨利·迈那斯和威利·普赖斯的接触中渐渐地找到了真爱,但最终却履行义务般地选择她自己并不爱的亨利作丈夫。本文着重探讨安娜对这两个男人的感情的双重性以及它所隐含的现实意义。 相似文献
7.
顾永跟 《湖州师范学院学报》1996,(5)
人工智能与数据库技术是计算机科学的两大重要领域,越来越多的研究成果表明,这两种技术的相互渗透将会给计算机应用带来更广阔的前景.本文综合论述了人工智能(AI)和数据库(DB)技术结合的重要性和必要性及其目前的研究概况,主要介绍了目前AI和DB结合的几个主要研究领域. 相似文献
8.
苏丽娜 《广西大学梧州分校学报》1999,(2)
在听力技能的教学中,我们的目的是提供能被学生理解、以内容为中心的、训练目的明确的听力练习,以便提高学生的听力能力。本文提出在选择听力理解练习前应考虑五个方面的内容。 相似文献
9.
利用学校网站的开放性、交互性、共享性为师生构建一个绿色、和谐、学习型的校园网络环境,为学校办公、信息交流和通讯架构平台,使学校逐步跨入电子化、无纸化办公阶段。 相似文献
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11.
用于乙醇-水分离的SA-PVA/PSF中空纤维渗透汽化复合膜 总被引：1，自引：1，他引：0
Using polysulfone (PSF) hollow fiber ultrafiltration membranes as the substrate, sodium alginate (SA) and polyvinyl alcohol (PVA) blend solutions as the coating solution, and maleic anhydride (MAC) as the cross-linked agent, SAPVA/PSF hollow fiber composite membranes were prepared for the dehydration of ethanol-water. The effects of different sodium alginate concentration in the coating solutions and different operating temperatures on pervaporation performance were investigated. The experimental results showed that pervaporation performance of the SA-PVA/PSF composite membranes for ethanol-water solution exhibited a high separation factor although they had a relatively low permeation flux. As SA concentration in SA-PVA coating solution was 66.7% and the operating temperature was 40 ℃, SA-PVA/PSF hollow fiber composite membrane (PS4) had a separation factor of 886 and flux of 12.6 g/(m2·h). Besides, SA-PVA/PSF hollow fiber composite membranes (PS3 and PS4) were used for the investigation of the effect of ethanol concentration in the feed solution on pervaporation performance. 相似文献
12.
制备了ＰＶＡ（聚乙烯醇）／ＣＭＣ（羧甲基纤维素）渗透汽化复合膜。研究了ＰＶＡ／ＣＭＣ用量比、交联剂用量、乙醇浓度、渗透汽化时间等因素对膜的渗透汽化性能的影响。发现ＰＶＡ／ＣＭＣ复合膜对８５－９８．３ｗｔ％乙醇溶液表现为水优先透过。在２６．５°Ｃ和１ａｔｍ下,９０．８ｗｔ％乙醇溶液渗透汽化３小时、膜内乙醇浓度增至９８．３ｗｔ％。达到了较好的醇／水分离效果 相似文献
13.
聚哌嗪均苯三甲酰胺/聚砜纳滤中空纤维复合膜对模拟纺织废水的截留性能,纳滤膜对染料有很好的截留率,其截留过程中筛分效应和荷电效应起主导作用。废水中染料浓度和无机盐浓度对纳滤膜截留性能有显著的影响。 相似文献
14.
分析了渗透膜分离性能评价过程中的关键问题,建立了渗透汽化/渗透萃取实验评测装置,并通过PDMS/PAN复合膜用于正辛烷/噻吩混合物的渗透汽化分离性能的实验评测,验证了实验装置所测结果的准确性和可信性。 相似文献
15.
1Introduction Generally,ultrafiltration(UF)asaseparationtech nologyofhighefficiencyandlowenergyconsumption haswidelybeenappliedinvariousindustries.Inin dustrialapplications,therearesixbasicUF modules[1]:(1)tubular,withinnerchannel diameters>4mm;(2)hollowfibers,withinnerdia metersof0.2-3mm;(3)plateunits;(4)spiral woundmodules;(5)pleated sheetcartridges;and(6)rotarymodules.However,hollowfiberUFmoduleis oneofmostimportantmodulesbecauseofitshigh areapackingdensity.Besides,UFtechnologyalsois us… 相似文献
16.
沈文豪 《上海大学学报(英文版)》1997,1(2):168-173
Inmicrobiaireactions.somesupersessionproductscanatfectviability'ofthemicroorganismsandgroWthofthecells.Forexample,ethanolproducedbyusingSaccharomycescaninhibitthegrowthofSaccharolnycesif]inananaerobiccondition.Thisphenomenoniscalledproductinhibition.Thedy… 相似文献
17.
Positively charged composite nanofiltration (NF) membranes with good stability were prepared by dopamine (DA) assisted poly(ethylene imine) (PEI) deposition on a polysulfone ultrafiltration (UF) substrate followed by a cross-linking step. Attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electronic microscopy, and atom force microscopy were employed to characterize the surface chemistry and morphology of the obtained composite membranes. The DA and PEI co-deposition conditions were optimized based on knowledge of the co-deposition mechanism. The effects of the cross-linker concentration, cross-linking time, and reaction temperature on the permeation and separation properties of the prepared composite membranes were investigated in detail. Under optimized conditions, the MgCl2 rejection and permeation flux of the composite membrane reached 80.4% and 19.6 L/(m2·h), respectively (the feed was 0.01 mol/L of MgCl2 solution under a test pressure of 0.4 MPa). The rejection of various salts followed the order MgCl2≈CaCl2>MgSO4>NaCl>Na2SO4, suggesting the membranes were positively charged. The composite membranes showed good durability under alkaline aqueous conditions. This study provided new insights into the fabrication of mussel-inspired thin-film composite nanofiltration membranes. 相似文献
18.
设计了氧化石墨烯/聚丙烯腈纤维膜油水分离性能的研究型综合实验。实验设计包括前期文献调研、氧化石墨烯的制备、氧化石墨烯/聚丙烯腈纤维膜的制备、膜分离性能测试等部分。教学实践表明,研究型综合实验的开展有利于提高学生综合运用各种专业知识的能力,有助于科研型、创新型人才的培养。 相似文献
19.
In an effort to find the effect of mass transfer ,surface tesion and drag forces on the velocity distribution,the mathematical model of the velocity profile of a nascent hollow fiber during membrane formation in the air gap region was numerically simulated by using the Runge-Kutta method (fourth-order method).The effect of mass transfer on velocity distribution based on the complicated function(G(Ch^s))was presented and the dffects of a complicated function were studied in two cases:in the first case,G(Ch^s) was constant;in the second,G(Ch^s) was variable.The latter was done by varying with the concentration of solvent in a nascent hollow fiber through the air-gap region.One empirical equation was used to describe this change and the predected values had a better agreement with the experimental values.To verify the moedl hypotheses,hollow fiber membranes were spun from 20:80 polybenzimidazole/polyetherimide dopes with 25.6 wt％ solid in N,N-dimethylacetamide (DMAc) using water as the external and internal coagulants.Based on the experimental results of dry-jet wet-spinning process for the fabrication of hollow fiber membranes,it is found that the model calculated values were in a good agreement with the experimental values. 相似文献
20.
Enrichment of semi-volatile organic acids from aqueous solutions by multiple-effect membrane distillation 总被引：1，自引：0，他引：1
Multiple-effect membrane distillation(MEMD) process for enriching semi-volatile organic acids from their individual aqueous solutions was performed by using a hollow fiber-based air gap membrane distillation(AGMD)module with the function of internal heat recovery.Aqueous solutions of glyoxylic acid,glycolic acid,lactic acid,pyruvic acid,malonic acid and glutaric acid were used as model feed.For a feed of 1%(mass fraction),each acid could be enriched for 8-20 times,which depended on the surface tension of the concentrate.The operation performance of MEMD process was characterized by permeation flux J,performance ratio PR and acid rejection rate R.The effects of cold feed-in temperature,heated feed-in temperature,feed-in volumetric flow rate and feed-in concentration on MEMD performance were experimentally evaluated.Maximum values of J,PR and R were 4.8 L/(h·m 2),9.84 and 99.93%,respectively.Moreover,MEMD process demonstrated a fairly good stability in a long-term experiment lasting for 30 d when aqueous solution of 4%(mass fraction) lactic acid was used as a feed. 相似文献