教师课堂评价偏见:形成、效应及矫正

在课堂评价中,教师往往形成关于学生的各式偏见。对于这些偏见不应无视、更不应拒斥,反而有必要将之整理为一种公开的知识。从形成看,教师课堂评价偏见通常源于"评价理念—评价实现"进程中具体环节和维度的偏差和误判。从效应看,教师课堂评价偏见对学生造成的负性影响主要包括投射效应、标签效应、晕轮效应和权威效应。教师课堂评价偏见的矫正在于使评价靠近学生而非把学生"框入"评价,对教师课堂评价知识与理论进行查漏补缺,课堂评价范式从"经验式评价"向"证据式评价"转变,课堂评价策略选择与运用从随意性过渡到专业性以及教师凭借课堂评价倾向反思实现评价行为优化。     

环境风险评价与安全风险评价的相关性研究

目前,对于如何开展安全风险评价和环境风险评价,未见有具体和详细的指导性建议。在许多的建设项目报告中,两类评价混淆严重,不利于突出两类评价各自的重点,也不利于风险评价工作的进一步发展。文章从基本概念入手,对两类风险评价在评价内容、评价程序和评价方法上的相关性问题进行了分析总结。同时阐述了环境风险评价与安全风险评价间的相关性和相异性。为环境风险评价和安全风险评价在实践评价过程中指明了各自具体的内容和重点,促进了环境风险评价工作的深入和发展。     

环境影响后评价工作内容研究——以码头建设项目后评价为例

《中华人民共和国环境影响评价法》是建设项目环境影响后评价的法律依据,中国环境影响后评价的起步较晚,相关制度正在完善,对于开展后评价的对象及评价内容,以及后评价相适应的技术方法,还需要根据不同情形进行深入探讨.通过探讨环境影响后评价的适用对象、适用情形、主要工作内容,并以某码头建设项目环境影响后评价为例,介绍了环境影响后评价的主要工作内容,希望为环境影响后评价工作的规范提供借鉴.     

环境空气质量综合指数评价方法探讨

目前,空气质量评价方法通常用指标评价法和综合指数评价法,与指标评价法相比指数评价法使评价结果更为客观。本文试图通过对综合污染指数法做一定修正,探讨一种更加科学客观的评价方法,结果表明：评价结果与环境空气质量实际情况能较好吻合。     

环境空气质量综合指数评价方法探讨

目前,空气质量评价方法通常用指标评价法和综合指数评价法,与指标评价法相比指数评价法使评价结果更为客观。本文试图通过对综合污染指数法做一定修正,探讨一种更加科学客观的评价方法,结果表明：评价结果与环境空气质量实际情况能较好吻合。     

模糊数学在大气环境质量评价中的应用

针对指数方法在评价大气环境质量中存在评价因素单一,不能反映多种污染物对大气环境的综合影响等缺点,结合模糊数学的原理与方法,提出应用模糊数学方法进行大气环境质量评价.介绍了模糊数学中的贴近度评价法和模糊综合评判法,建立了评价模型、评价标准和评价步骤.以普兰店市大气环境质量评价为例阐明了两种模糊评价方法的比较与应用,并根据评价结果分析了模糊数学在大气环境质量评价中的优缺点.     

地下空间安全评价方法综述

针对地下空间安全评价方法的的研究现状,本文综述了地下空间安全性影响指标、评价对象、安全评价方法的评价体系,并提出安全评价的难点及发展趋势。介于地下空间复杂性的特点,影响安全性指标复杂多样,评价对象分单灾种和多灾种,评价方法也不是单一确定。比较不同评价对象及使用的评价方法。介绍主要的安全评价方法,包括层次分析法、模糊综合评价、TOPSIS法、灰色关联度分析、神经网络、仿真技术,并对各评价方法进行优缺点对比。此外研究了安全评价难点和热点,对未来的发展趋势做预测。地下空间安全评价的结果具有一定的说服力,但不能唯一确定地下空间安全性。     

战略环境评价的系统分析

介绍了战略环境评价系统的组成要素,即评价者、评价对象、评价目的、评价标准和评价方法,分析了其相互关系及各要素与战略环境评价系统的关系,通过对战略环境评价的战略结构分析,提出了战略环境评价的工作程序.     

区域生态风险评价研究进展

生态风险评价是近十几年逐渐兴起并得到迅速发展的一个研究领域,区域生态风险评价作为生态风险评价的一个发展方向,由于其空间异质性和评价过程的复杂性,成为了目前的研究难点与热点。文章回顾了生态风险评价的发展历程:由最初的意外事故风险评价发展到环境风险评价再到生态风险评价、区域生态风险评价,风险因子由单一发展到多元,评价范围由种群、局地扩展到景观、区域。同时介绍了国内外区域生态风险评价的研究进展;分析了各种评价模型的优缺点,探讨了区域生态风险评价过程中存在的问题及解决方法。展望了区域生态风险评价今后的发展方向。     

对小学数学教学中开展发展性评价的探讨

评价是课堂教学的一项重要内容,在课堂教学中要积极探索发展性评价,树立"一切为了学生发展"的教育评价理念,努力实现综合化的评价内容、动态化的评价过程、多样化的评价方式、多元化的评价主体,这样的评价才有利于学生的学习,有利于学生的成长,有利于学生的发展。     

Effects of humic acid coatings on phenanthrene sorption to black carbon

Black carbon (BC) can strongly adsorb hydrophobic organic compounds (HOCs).The HOC sorption to coated BC could be attenuated in soil and sediment compared with that of the parent BC.To study the potential causes of the sorption attenuation,humic acid (HA) and BC were isolated.Phenanthrene (PHE) was selected as the representative of HOCs.BC was coated with the precipitated HA.The PHE sorption to the HA-coated BC was determined.The HA coatings on BC could result in the significant sorption attenuation of PHE to BC.The attenuation varied in different HA origin and was positively correlated to the aromaticity of HA.The attenuation could be explained by the direct competition between HA and PHE for the available sorption sites on BC and the reduction of the available sorption sites as a result of the pore blockage of BC caused by the HA coatings.Therefore,the HA coatings on BC was one potential cause of the attenuation of HOC sorption to BC in soil and sediment.     

A new photon kinetic-measure based on the kinetics of electron-hole pairs in photodegradation of textile wastewater using the UV-H2O2FS-TiO2 process

Actual textile wastewater and synthesized wastewater containing various textile dyes were photocatalytic degraded by the UVH2O2Fs-TiO2 process in an aimular-flow photocatalytic reactor. In this process, a photon kinetic-measure was adopted to obtain constant rates of dyes decomposition. It was theorized that, by illumination at different UV frequencies, the electrons within the semiconductor were excited from the valence band to the conduction band, yielding the formation of electron-hole pairs which are the pre-requisites for photocatalysis. CPT （critical photonic time） exposure required to cause 90% of vibrations between the double and single bonds along the molecular chain of the dyes to be oxidized, was taken to measure the photocatalytic activities. The CPTs varied with the frequencies of the UV spectral areas. The derivatization of CPT from the first-order kinetic law was presented.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Isolation and algae-lysing characteristics of the algicidal bacterium B5

Water blooms have become a worldwide environmental problem.Recently,algicidal bacteria have attracted wide attention as possible agents for inhibiting algal water blooms.In this study,one strain of algicidal bacterium B5 was isolated from activated sludge.On the basis of analysis of its physiological characteristics and 16S rDNA gene sequence,it was identified as Bacillusfusiformis.Its algae- lysing characteristics on Microcystis aeruginosa,Chlorella and Scenedesmus were tested.The results showed that:(1)the algicidal bacterium B5 is a Gram-negative bacterium.The 16S rDNA nucleotide sequence homology of strain B5 with 2 strains of B.fusiformis reached 99.86%,so B5 was identified as B.fusiformis;(2)the algal-lysing effects of the algicidal bacterium B5 on M.aeruginosa, Chlorella and Scenedesmus were pronounced.The initial bacterial and algal cell densities strongly influence the removal rates of chlorophyll-α.The greater the initial bacterial cell density,the faster the degradation of chlorophyll-α.The greater the initial algal cell density,the slower the degradation of chlorophyll-α.When the bacterial cell density was 3.6 x l07 cells/ml,nearly 90% of chlorophyll-αwas removed.When the chlorophyll-αconcentration was less than 550μg/L,about 70% was removed;(3)the strain B5 lysed algae by secreting metabolites and these metabolites could bear heat treatment.     

Emissions of SO2, NO and N2O in a circulating fluidized bed combustor during co-firing coal and biomass

This paper presents the experimental investigations of the emissions of SO2, NO and N2O in a bench scale circulating fluidized bed combustor for coal combustion and co-firing coal and biomass. The thermal capacity of the combustor is 30 kW. The setup is electrically heated during startup. The influence of the excess air, the degree of the air staging, the biomass share and the feeding position of the fuels on the emissions of SO2, NO and N2O were studied. The results showed that an increase in the biomass shares resulted in an increase of the CO concentration in the flue gas, probably due to the high volatile content of the biomass. In co-firing, the emission of SO2 increased with increasing biomass share slightly, however, non-linear increase relationship between SO2 emission and fuel sulfur content was observed. Air staging significantly decreased the NO emission without raising the SO2 level. Although the change of the fuel feeding position from riser to downer resulted in a decrease in the NO emission level, no obvious change was observed for the SO2 level. Taking the coal feeding position R as a reference, the relative NO emission could significantly decrease during co-firing coal and biomass when feeding fuel at position D and keeping the first stage stoichiometry greater than 0.95. The possible mechanisms of the sulfur and nitrogen chemistry at these conditions were discussed and the ways of simultaneous reduction of SO2, NO and N2O were proposed.     

Adsorption thermodynamics and kinetic investigation of aromatic amphoteric compounds onto different polymeric adsorbents

The adsorption behavior of p-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature.Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm.The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest,which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid.The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid.Thermodynamic studies suggested the exothermic,spontaneous physical adsorption process.Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step.     

Formation of multiple trimethylsilyl derivatives in the derivatization of 17α-ethinylestradiol with BSTFA or MSTFA followed by gas chromatography-mass spectrometry determination

N,O-bis(trimethylsily)trifluoroacetamide (BSTFA) and N-methyl-N(trimethylsily) trifluoroacetamide (MSTFA) are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone (E1) and 17(-ethinylestradiol (EE2). In this study, three trimethylsilyl (TMS) steroid derivatives, mono-and di-trimethylsilyl EE2 and mono-trimethylsilyl E1, were observed during the derivatization of EE2 with BSTFA or MSTFA and/or GC separation. Factors influencing the production of multiple TMS derivatives and their relative abundance were examined. It was found that both methanol and bisphenol A competed with estrogenic esteroids when reacting with silylation reagents, and thus affected the formation of TMS derivatives and their relative abundance in the derivatization products. Methanol was found to be more reactive than bisphenol A with the BSTFA reagent. None of the three solvents tested in this study could prevent the generation of multiple TMS derivatives during the derivatization of EE2 with BSTFA, followed by GC analysis. A similar result was observed using MSTFA as the derivative reagent followed by GC analysis. Thus, the suitability of BSTFA or MSTFA as the derivatization reagent for the determination of E1 and EE2 by GC-MS, under the conditions reported here, is questionable. This problem can be solved by adding trimethylsilylimidaz (TMSI) in the BSTFA reagent as recommended, and the performance of the method has been proved in this study.     

Treated wastewater irrigation effect on soil, crop and environment： Wastewater recycling in the loess area of China

A study was carried out at the Loess Plateau in Dongzhi,China,to test the feasibility of using secondary treatment sewage effluent and to determine whether the water quality would then meet the recommended irrigation norm.Seven crops,including celery,wheat, maize,millet,apples,rapeseed and yellow beans,were tested in the study.Physical and chemical properties of the soil,crop yield and quality and leachate at different soil depths were measured.In most cases,the quality of the crops that made use of treated sewage was not distinctively different from those that did not use treated sewage.However,yields for the former were much higher than they were for the latter.Leachates at different soil depths were analyzed and the results did not show alarming levels of constituents.For a period of approximately 14 months,the treated sewage irrigation had no significant effect on the loess soil and no cases of illness resulting from contact with the treated sewage were reported.With treated sewage irrigation,a slight increase in the organic content of the soil was observed.