优秀教师评价学生学业的策略与技巧

学业评价是教师教育教学中的重要环节,不仅关系到对学生的评价,也关系到学生对学习的情感态度和努力投入,以及师生关系的质量。优秀的中小学教师在评定学生学业成绩时,能够从学生长远发展角度考虑评价对学生的全面影响,重视评分的发展性评价目的;在具体评分实践中,能充分考虑学生对分数的认识、理解和感受,评分目的明确;能够运用多种评价方式,从多个来源对学生多个方面的表现实施多元综合评价;能够根据评分目的和条件合理恰当地选择评分标准,评分灵活可靠,又不失评价原则。这些理念和策略作法,确保了他们的评分能够真正发挥鼓励学生学习,促进学生成长的广阔而深远的目的。     

Distribution and abundance of euphausiid larvae and salps during austral summers in Prydz Bay, Antarctica

The distribution and abundance of euphausiid larvae and salps was studied from samples collected in 2002 and 2006 from Prydz Bay, Antarctica.Larvae of Thysanoessa macrura and Euphausia superba were mainly distributed in the north of the continental shelf. T. macrura was more abundant and had a relatively wider distribution. In 2006, with ice having retreated and higher seawater temperatures and chlorophyll a levels, E. superba and T. macrura occurred in higher abundances and at more mature developmental stages. Euphausia crystallorophias was mainly distributed in the neritic region. In 2002, with severe ice conditions in the neritic region, abundance of E. crystallorophias was consisted of metanauplius (MN) and calyptopis I (CI). Salps, mostly Salpa thompsoni, had a low abundance in Prydz Bay. In 2002, S. thompsoni was only m)-3. In 2006, S. thompsoni was found at three stations located near the contimental factors, such as the timing of ice melt, polynya formation and food concentration appear to have a marked effect on the distribution and abundance of euphausiid larvae and salps.     

In situ determination of hafnium isotopes from rutile using LA-MC-ICP-MS

The hafnium isotopic analysis using laser ablation has been widely conducted on Hf-rich minerals(zircon/baddeleyite/ calzirtite/eudialyte), however, little work has been reported on Hf-poor(100 ppm) minerals. This work presents a detailed procedure of in situ hafnium isotopic analysis from rutile using laser ablation multiple collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS). The rutile U-Pb dating reference material JDX shows homogeneous hafnium isotopic ratios, with 176Hf/177Hf=0.281795±0.000015(2SD, n=33) and 176Lu/177Hf=0.000018±0.000004(2SD, n=17) that suggest the possibility of using JDX as a new reference material hafnium isotopic measurement. We also measure hafnium isotopic compositions of other rutile U-Pb dating reference material(R10, Sugluk-4 and PCA-S207) and the 176Hf/177 Hf values are similar to previously reported results, which confirms that we can acquire accurate and precise hafnium isotopic compositions using our developed analytical protocol. We analyzed hafnium isotopic compositions and U-Pb ages of rutile in high-temperature and ultrahigh-temperature granulites from various terrains of the Khondalite Belt from the North China Craton, combined with zircon results in the same area, suggesting that the metamorphic evolution history of the granulite is much more complicated than previously thought.     

Axial load tests and numerical modeling of single-helix piles in cohesive and cohesionless soils

Acta Geotechnica - Small-diameter helical piles have been increasingly used in Western Canada, but there is a lack of research. The present research investigates the axial behavior of three types...     

Modeling the influence of urbanization on urban pluvial flooding: a scenario-based case study in Shanghai,China

Natural Hazards - Rapid urbanization has brought great productivity, prosperity and challenges to Shanghai in the last few decades. This paper focuses on the influence of urbanization on urban...     

矿物纤维粉尘的表面特性及对生物活性的影响

通过对矿物纤维粉尘对人体的危害性及对环境影响的研究，提出了一些矿物产生毒理作用过程的假说和因素判定；研究了矿物与生物体之间的相互作用时应重视矿物表面－细胞物理化学作用，并依据初步试验提出表面特征是矿物纤维表征生物活性的关键因子（如表面活性域、催化作用等），而纤维性只是矿物表面特性的表征因素之一。     

Performance of multiple tuned mass dampers for attenuating undesirable oscillations of structures under the ground acceleration

Multiple tuned mass dampers (MTMDs) consisting of many tuned mass dampers (TMDs) with a uniform distribution of natural frequencies are considered for attenuating undesirable vibration of a structure. The MTMD is manufactured by keeping the stiffness and damping constant and varying the mass. The structure is represented by its mode‐generalized system in the specific vibration mode being controlled using the mode reduced‐order method. The optimum parameters of the MTMD are investigated to delineate the influence of the important parameters on the effectiveness and robustness of the MTMD by conducting a numerical searching technique in two directions. The parameters include: the frequency spacing, average damping ratio, mass ratio and total number. The criterion selected for the optimization is the minimization of the maximum value of the dynamic magnification factor (DMF) of the structure with MTMD (i.e. Min.Max.DMF). In this paper, for the sake of comparison, the MTMD(II), which is made by keeping the mass constant and varying the stiffness and damping coefficient, and a single TMD are also taken into account. It is demonstrated that the optimum frequency spacing of the MTMD is the same as that of the MTMD(II) and the optimum average damping ratio of the MTMD is a little larger than that of the MTMD(II). It is also found that the optimum MTMD is more effective than the optimum MTMD(II) and the optimum single TMD with equal mass. Copyright © 2000 John Wiley & Sons, Ltd.