An overview of structure-soil-structure dynamic interaction research

The concept of structure-soil-structure dynamic interaction was introduced and the research methods were summarized. Based on lots of documents, a systematic summary of the history and current situation of structure-soil-structure dynamic interaction research considering adjacent structures was proposed as reference for researchers. The existing matter and the prospect of future research trend in this field was also examined.     

Research on the construction and application of teacher-student interaction evaluation system for smart classroom in the post COVID-19

Smart classroom (SC) is an important embodiment of the new teaching mode in online and offline integration in the COVID-19. At present, the research on the evaluation system of teacher-student interaction (TSI) in SC lacks evaluation system to guide the development of students’ higher order thinking (HOT). This evaluation system of TSI was established through grounded theory, Delphi method and analytic hierarchy process. The evaluation system for TSI considered the support of intelligent technology for various indicators and the development of students’ HOT. The evaluation system included 4 first level indicators, 16 s level indicators and 44 third level indicators. The evaluation system had been comprehensively evaluated the TSI activities, which was conducive to the development of students’ HOT.Data availabilityData used in this research are available upon request from the corresponding author.     

Evaluation and optimization of secondary water supply system renovation

Due to pollution in second water supply system (SWSS),nine renovation alternative plans were proposed and com-prehensive evaluations of different plan based on Analytical Hierarchy Process (AHP) were presented in this paper. Comparisons of advantages and disadvantages among the plans of SWSS renovations provided solid foundation for selecting the most appro-priate plan for engineering projects. In addition,a mathematical model of the optimal combination of renovation plans has been set up and software Lingo was used to solve the model. As a case study,the paper analyzed 15 buildings in Tianjin City. After simulation of the SWSS renovation system,an optimal scheme was obtained,the result of which indicates that 10 out of those 15 buildings need be renovated in priority. The renovation plans selected for each building are the ones ranked higher in the com-prehensive analysis. The analysis revealed that the optimal scheme,compared with two other randomly calculated ones,increased the percentage of service population by 19.6% and 13.6% respectively,which significantly improved social and economical benefits.     

Numerical simulation of interaction between laminar flow and elastic sheet

A numerical simulation of the interaction between laminar flow with low Reynolds number and a highly flexible elastic sheet is presented. The mathematical model for the simulation includes a three-dimensional finitevolume based fluid solver for incompressible viscous flow and a combined finite-discrete element method for the three-dimensional deformation of solid. An immersed boundary method is used to couple the simulation of fluid and solid. It is implemented through a set of immersed boundary points scattered on the solid surface. These points provide a deformable solid wall boundary for the fluid by adding body force to Navier-Stokes equations. The force from the fluid is also obtained for each point and then applied on the boundary nodes of the solid. The vortex-induced vibration of the highly flexible elastic sheet is simulated with the established mathematical model. The simulated results for both swing pattern and oscillation frequency of the elastic sheet in low Reynolds number flow agree well with experimental data.     

柚子皮对水中六价铬的吸附性能研究

采用柚子皮制备生物吸附剂用于去除水中的Cr(VI),考察了p H值、柚子皮投加量、柚子皮粒径、溶液离子强度、反应温度等因素对吸附效果的影响。结果表明,当溶液中Cr(VI)离子初始浓度15mg/L、p H 1.5、反应温度25℃、柚子皮投加量1.0g/100 m L、吸附时间7 h时,Cr(VI)离子去除率可达90%以上。柚子皮对Cr(VI)离子的吸附过程可以用Langmuir和Freundlich吸附等温模型来描述,吸附等温线线性相关性均较显著,吸附过程符合准二级动力学方程。柚子皮对水中Cr(VI)离子吸附性能较好,且运行成本低,可推广应用于水中重金属离子的治理。     

谈地理信息系统(GIS)在水土流失中的应用领域

GLS是现代地理科学与空间信息科学相结合的产物,是现代地学领域十分重要的一门分析和应用工具,水土流失是地学与生态学领域多门学科的交叉学科,对空间信息的依赖性很强．本文介绍了GIS的概况,就水土流失的学科特点论述了适于GIS应用的若干领域,并对今后GIS在水土流失学科中的可能应用领域进行了探讨。     

Science Letters:Detection of Catabacter hongkongensis in polluted European water samples

The Catabacteriaceae is a new bacterial family with a unique member: Catabacter hongkongensis is a strictly anaerobic, non-sporulating, Gram-positive coccobacillus that is phylogenetically related to some clostridial clusters. Little is known of its epidemiology and environmental distribution, but the inclusion of its 16S rRNA gene sequence in GenBank has allowed it to be detected qualitatively. As a first approach for prospective surveys, a real-time polymerase chain reaction (PCR) procedure to identify C. hongkongensis has been developed. The presence of Catabacteriaceae in 29 water bodies subjected to possible human or animal impact has been investigated. Four of them were positive. The results confirm that highly polluted water can contain C. hongkongensis.     

Novel FGBAC reactor for controlling the leakage of microfauna in drinking water treatment

In order to reduce the microfauna leakage risk from a granular biological activated carbon （GBAC） reactor which employs granular activated carbon （GAC） as adsorption media in drinking water advanced treatment, a novel fiber and granular biological activated carbon （FGBAC） reactor which employs both GAC and activated carbon fiber （ACF） as adsorption media, was developed. The results showed that the species composition of microfauna leaking from FGBAC reactor is almost similar to that leaking from GBAC reactor, however the densities of microfauna leaking from FGBAC reactor is reduced by 26%-81% compared to those leaking from GBAC reactor. In addition, compared to GBAC reactor, FGBAC reactor can increase the removal efflciencies of chemical oxygen demand （COD） and turbidity by 7% and 10%, respectively, during the stable operation period of reactor.     

Effects of small water clusters on the growth and microcystin production of Microcystis aeruginosa

Microcystis aeruginosa FACHB 905 was used as a model organism to study the effects of small water clusters(SWCs) on the growth and microcystin(MC) production of toxic cyanobacteria.The results showed that SWCs were able to stimulate the growth of Microcystis aeruginosa,which resulted in increased cell numbers and higher specific growth rates after a 30-d treatment.The cell morphology indicated that Microcystis aeruginosa was in a better state of growth,and it was more prone to divide in SWCs than in normal water clusters.The SWCs treatment up-regulated MC synthesis and exudation in 10 d in Microcystis aeruginosa,and the intra-cellular MC content decreased after the 20th day subsequently.Moreover,the cellular photosynthetic pigment contents were temporarily stimulated by SWCs.A possible reason is that SWCs stimulated the growth by promoting photosynthesis,whereas the increased MC production was relevant to pigment contents.     

Life cycle cost analysis of new FRP based solar parabolic trough collector hot water generation system

Parabolic trough collectors （PTCs） are employed for a variety of applications including steam generation and hot water generation. This paper deals with the experimental results and an economic analysis of a new fibre reinforced plastic （FRP） based solar PTC with an embedded electronic controlled tracking system designed and developed for hot water generation in a restaurant in Madurai, India. The new collector performance has been tested according to ASHRAE Standard 93 （1986）. The performance of a new PTC hot water generation system with a well mixed hot water storage tank is investigated by a series of extensive tests over ten months period. The average maximum storage tank water temperature observed was 74.91℃, when no energy is withdrawn from the tank to the load during the collection period. The total cost of the new economic FRP based solar PTC for hot water generation with an embedded electronic controlled tracking system is Rs. 25000 （US$ 573） only. In the present work, life cycle savings （LCS） method is employed for a detailed economic analysis of the PTC system. A computer program is used as a tool for the economic analysis. The present worth of life cycle solar savings is evaluated for the new solar PTC hot water generation system that replaces an existing electric water heating system in the restaurant and attains a value of Rs. 23171.66 after 15 years, which is a significant saving. The LCS method and the MATLAB computer simulation program presented in this paper can be used to estimate the LCS of other renewable energy systems.     

面向精准灌溉的农田水势软测量

根据土壤-作物-大气连续体(SPAC)理论,水分在连续体内的运动主要由水势差决定。准确测定农田水势对于实施精准灌溉十分重要。文章介绍了基于农作物微环境信息采集与处理,通过混合软测量模型整体估算农田水势的新方法。     

快速式燃气热水器燃烧系统模拟

模拟了一种常规快速式燃气热水器的燃烧系统,研究了不同压力状况下的燃烧工况.得到的数值模拟结果与实验获得的数据吻合得较好,证明了所用物理模型和数学模型的合理性.结果显示,火焰高度和过剩空气系数依赖于系统出口和入口的静压差,而与燃烧室内的绝对压力无关.该静压差和系统中用于燃烧的空气量显著影响CO的生成,与CO的生成量呈反比关系,并同时影响燃烧区域内的温度场和速度场.为降低CO排放水平,必须增加进入燃烧系统的空气量,因此需要增加风机输出功率以提供足够的空气压头.该研究为设计快速式燃气热水器提供了一种行之有效的方法.     

Experimental investigation of an adjustable ejector for CO2 heat pump water heaters

An adjustable ejector expansion device for a CO2 heat pump water heater （HPWP） is proposed to improve the system performance. It has been designed to investigate experimentally the effects of the motive nozzle throat area of the ejector, entrained flow pressure, back pressure and primary flow pressure on the entrainment ratio. Experiments based on different motive nozzle throat areas were conducted and the results of the prototype ejector using CO2 as working fluid are presented. The results show that an adjustable ejector can achieve high performance and work well in a wide range of working conditions.     

Simulation investigation on fluid characteristics of jet pipe water hydraulic servo valve based on CFD

Simulation investigation on fluid characteristics of the water hydraulic jet pipe servo valve (WHJPSV) is conducted through a commercial computational fluid dynamics (CFD) software package FLUENT. In particular, the factors to fluid characteristics of WHJPSV are addressed, which include diameter combination of jet pipe and receiver pipe, jet pipe nozzle clearance, angle between two jet receiver pipes and deflection angle of the jet pipe. It is concluded from the results that: (i) Structural parameters have ...     

衬铂平台石墨炉原子吸收光谱法测定环境水样中的痕量汞

利用衬铂平台石墨炉ＺＥＥＭＡＮ原子吸收光谱法直接测定环境水样中的痕量汞,对衬台石墨炉测汞的最佳测试参数,条件进行系统研究,本方法的灵敏度为普通平台石墨炉的５倍以上,检出限为０．２μｇ／ｌ加标回收率为８８．６－１０９％;相对标准偏差小于４．９５％。     

地铁荷载下隧道周围粉性土孔压的单因素试验

为了研究地铁荷载作用下饱和粉性土的孔隙水压力特性,针对上海地铁10号线国权路附近的饱和粉性土进行多功能GDS循环三轴试验,考虑了振动频率、动应力幅值及固结比等因素对孔隙水压力的影响。试验结果表明:土体遭受地铁振动荷载作用下,孔隙水压力经过三个阶段的变化过程,即快速增长-缓慢增加-衰减稳定。相同振动频率及固结比条件下,动应力幅值越大,产生的孔隙水压力越大;相同动应力幅值及固结比条件下,频率越小,产生的孔隙水压力越大;相同动应力幅值及振动频率条件下,固结比越大,产生的孔隙水压力越大。采用单因素设计法及方差分析,得到振动频率、动应力幅值及固结比等因素均对孔隙水压力有非常显著的影响。     

诏安县水土流失遥感调查及总体态势评估

利用遥感影像解译1995、2004、2012年3期的水土流失图,分析诏安县的水土流失变化趋势及空间分布,并以行政村为单元对其1995年以来水土流失的总体态势做出评估.研究认为,1995年以来诏安县水土流失面积持续下降,但下降趋势趋缓;水土流失总体态势改善明显,但中东部地区水土流失有所加重.     

表观黏度法研究聚丙烯酰胺与聚乙二醇在水中的相互作用

采用表观黏度法,以黏度增长因子R为指标,对聚丙烯酰胺(PAM)与聚乙二醇(PEG)在水中的相互作用进行研究,并考察PAM摩尔分数、PEG相对分子质量、剪切速率和温度对其相互作用的影响。结果表明:混合体系中PAM与PEG之间的相互作用表现为表观黏度的降低,主要为疏水、氢键及相互缠结作用等;当体系中PAM的摩尔分数为0.6时,相互作用最强;该作用随PEG相对分子质量的增大而略增强,随剪切速率的增加先增大后减小,随温度的升高先减小后增大。表观黏度法快捷简便,适用于溶液中聚合物分子间相互作用的研究。     

Analysis of genetic diversity in banana cultivars (Musa cvs.) from the South of Oman using AFLP markers and classification by phylogenetic, hierarchical clustering and principal component analyses

Banana is an important crop grown in Oman and there is a dearth of information on its genetic diversity to assist in crop breeding and improvement programs.This study employed amplified fragment length polymorphism(AFLP) to investigate the genetic variation in local banana cultivars from the southern region of Oman.Using 12 primer combinations,a total of 1094 bands were scored,of which 1012 were polymorphic.Eighty-two unique markers were identified,which revealed the distinct separation of the seven cultiva...