高中英语课堂误区探究

高中英语课堂如何能做到高效、实用,是近些年众多一线英语教师试图解决的核心问题。在长期的教学实践过程中,以"主动参与、乐于探究、合作交流"为特征的学习方式正逐步被高中课堂所接纳,这种探究型学习方式是以外语学习的认知理论观点为依据,强调学生的自主学习,给学生营造一个宽松、民主、和谐的心理氛围。然而正是探究性学习的这种开放性特点,使得许多教师设计不好探究学习的教学步骤,处理不好探究学     

开放式作文教学之我见

开放式作文教学,作为一种教学思想、教学模式和教学实践,是语文课程改革带给作文教学的最显著突破。它不仅指作文题目的开放,文体的开放,还包括写作时间、空间的开放,写作形式的多样化,这有利于学生的思维向多方向开拓,以探寻学生最喜闻乐见或感受最深的材料进行写。但不是学生想写什     

高职院校学生学习绩效评价现状调研

本文经国内外理论梳理和对常州科教城走访调研,认为在高职院校学生学习绩效评价中,必须把评价主体设定为学生,或至少学生评价权数加大,使之更加切合时代特点和高职生自身特色。     

张岱那年看的雪

湖心亭看雪 [明]张岱 崇祯五年十二月,余住西湖.大雪三日,湖中人鸟声俱绝.是日更定①矣,余拏②一小舟,拥毳衣③炉火,独往湖心亭看雪.雾凇沆砀④,天与云与山与水,上下一白.湖上影子,惟长堤一痕、湖心亭一点,与余舟一芥、舟中人两三粒而已. 到亭上,有两人铺毡对坐,一童子烧酒,炉正沸.见余,大喜日:“湖中焉得更有此人!”拉余同饮.余强饮三大白而别.问其姓氏,是金陵人,客此.及下船,舟子喃喃日:“莫说相公痴,更有痴似相公者!     

基于LIBS技术的钢铁合金中元素多变量定量分析方法研究

针对钢铁合金样品元素组成相对复杂,基体效应较严重的问题,利用激光诱导击穿(LIBS)光谱技术对钢铁合金中的元素进行了定量分析。以Nd∶YAG脉冲激光器基频1 064 nm波长激光作为激发光源,采用中阶梯光栅光谱仪和ICCD分光探测钢铁合金样品的LIBS光谱。通过优化实验确定最佳探测延时为1.5 μs,最佳探测门宽为2 μs,激光聚焦点位置在实验样品靶面以下1.5 mm。采用单变量定量分析、多变量线性回归和偏最小二乘(PLS)三种方法分析钢铁合金中Cr元素和Ni元素的含量。结果表明,采用单变量定标方法定标曲线相关系数不高,对待测样的预测误差相对较大,难以有效地定量分析基体元素复杂的钢铁合金中金属元素的含量;采用多变量线性回归分析方法能有效提高定量分析的精度;采用PLS方法得到的Cr和Ni元素的拟合曲线相关系数r分别为0.981和0.995,对两个待测样品中Cr元素和Ni元素的预测相对误差在6.4%和7.1%以内,分析结果优于多变量线性回归方法。可见,采用多变量校正的PLS方法能更有效地校正基体效应对定量分析的影响,提高定量分析的精度。     

多重胞元和规则多重分形

以超级分形纤维和双重分形纤维的研究结果为基础,达成了如下目标:首先,归纳、抽象出了多重胞元概念;其次,基于多重胞元概念,证实:具有严格自相似性的规则多重分形,不仅是可构造的,而且其构造模式具有普遍性;再者,通过分析构造模式,发现:任何规则多重分形,都可以在多重胞元意义下,被精确地等价成具有多重精细结构的广义单重分形．而基于这种等价性,单重分形维数公式就能够推广至规则多重分形维数公式,单重分形几何就能够推广至规则多重分形几何;最后,借助规则多重分形,构造了几种黄金分形．     

“服装”中化学教学资源的开发与利用

化学与生活息息相关,“服装”中蕴含着丰富的教学资源。结合课程标准,从服装面料、染料与染色、纺织品功能整理、鉴别与修复四个方面,以“化学的眼光”对服装相关内容进行了解构和重整。在教学中,要紧密联系学生生活实际,增强对化学与生活紧密关联的认识;适时开展项目式教学,以培养学生的实践能力和创新精神;结合文明的历史进程,厚植爱国情怀,以提升中华民族的文化自信。     

Crystal structures and electronic properties of solid fluorine under high pressure

As the previously proposed structures of C2/m and C2/c possess similar enthalpies and x-ray diffraction patterns, the space group of fluorine at ambient pressure is in controversy. We successfully obtain its thermodynamically stable lowpressure phase, which shares the same structure as the earlier known C2/c. Further investigations on phonon spectra reveal the instability of the C2/m structure with imaginary frequency in the Brillouin zone and confirm the dynamically stable property of the C2/c structure at the same time. Compressing fluorine up to 8 GPa, the C2/c phase is found to undergo a phase transition to a new structure with a space group of Cmca. Electronic energy band structures indicate the insulating feature of C2/c and Cmca with no bands across the Fermi level. The infrared(IR) and Raman spectra of C2/c and Cmca at selected pressures are calculated to provide useful information to future experiments.     

Toroidal rotation induced by 4.6 GHz lower hybrid current drive on EAST tokamak

Using a tangentially viewing x-ray imaging crystal spectrometer, substantial co-current rotation driven by lower hybrid current drive(LHCD) at 4.6 GHz is observed on EAST tokamak. This study presents plasma rotation behaviors with 4.6 GHz LHCD injection. Typically, the 10-20 km/s co-current rotation change and the transport of rotation velocity from edge to core are observed. The relationship between plasma parameters and rotation is also investigated, indicating that rotation decreases with increasing internal inductance(l_i) and increases with increasing safety factor(q_0). Hysteresis between rotation and T_e plasma stored energy is observed, suggesting different response times between the electron heating and rotation acceleration by LHCD. A comparison between the rotations driven by 4.6 G LHCD and 2.45 G LHCD on EAST is also presented, in which higher frequency LHCD could induce more rotation changes.