基于体验的物理实验教学情境设计策略

基于体验的物理实验教学情境设计是运用科学思维方法对物理实验进行创新开发与优化设计,以体 现实验教学对提高学生科学素养的意义,某种程度上是教师将自身教学思想和理念通过情境设计进行显性化的表 达     

[Cl2FeS2MoS2FeCl2]^2^-阴离子的FT-IR光谱和简正坐标分析

在500-100cm^-^1波段范围内测定了[Cl2FeS2MoS2FeCl2]^2^-簇阴离子的Fourier变换红外光谱.采用简化的普遍价力场(SGVFF)进行了简正坐标分析.振动基频的计算值与观测值符合良好,两者平均偏差小于1.0%证实了振动谱带的归属;确定了包括伸缩、变角、扭曲以及伸缩-伸缩相互作用的16个力常数.最后还讨论了所得结果的合理性和可靠性.     

湘西金银花挥发油化学成分研究

采用ＧＣ／ＭＳ／ＤＳ联用仪对湘西金角花挥发油中的化学成分进行了研究。并鉴定出４０种组分。其主要成分为：芳樟醇、环氧芳樟醇、α－萜品醇、顺－３－已 烯醇、顺芷酸－３、己烯酯、香叶醇、氧化芳樟醇、法尼醇、顺－苯酮、法尼烯、大根香叶烯、橙花醇等。其中芳樟醇含量最高,约占精油总量的２０％。     

GH4169高温合金锥形机匣旋压轮廓精度控制与研究

零件轮廓精度是旋压件成形质量评判标准之一.在Simufact有限元软件中进行GH4169高温合金锥形机匣的普通旋压仿真试验,观察到影响旋压件轮廓精度的常见缺陷:底部隆起、底部减薄、回弹.通过对照法对底部隆起进行尾顶块控制.采用单因素试验法探究成形过程中主要工艺参数(旋轮进给比、芯模转速、道次间距)对底部减薄和工件回弹量的影响规律,以最大底部减薄量和平均回弹角度为评价指标.结果表明:进给比对底部减薄影响最大,道次间距对回弹影响最大.综合对底部减薄和回弹的控制,针对试验件工艺参数应选择较大道次间距p=20 mm,较小旋轮进给比f=0.8 mm·r^-1或较大旋轮进给比f=1.6 mm·r^-1,较大的芯模转速n=500 r·min^-1.     

平衡电桥法测量金属丝弹性模量

金属丝在受到轴向拉力时,其长度与横截面积会发生微小的变化,其阻值也会发生相应的变化。利用惠斯登电桥测量出金属丝在拉伸时的阻值变化,设计了一种实验精度较高且操作简便的测量金属丝弹性模量的方法。     

质子数Z 分别位于Ru 之上和之下的A~(100~126) 丰中子原子核三轴形变在原子核形状变迁和共存中的重要作用(英文)

基于Ru (Z = 44) 丰中子同位素中存在最大三轴形变的理论预言和实验证据,综述了近年来Rh (Z = 45),Pd (Z =46), Ag (Z =47), Cd (Z =48)(质子数Z 位于Ru,Z =44 之上)及Zr (Z =40), Nb (Z =41), Mo (Z =42),Tc (Z =43)(质子数Z 位于Ru,Z =44 之下) 的A~ (100~126) 丰中子同位素中关于三轴形变的形状变迁和形状共存系统性研究的重要进展。252Cf 自发裂变瞬发 射线-- 三重符合、特别是新建立的--- 四重符合数据的系统观测和研究,在Ru, Pd, Cd 和Nb 丰中子同位素中显著扩展或首次观测到了一系列能带,为这个核区原子核形状的研究提供了新的、重要的实验数据。联系此前报道的有关进展,使用PES, TRS, PSM, CCCSM 和SCTAC 理论模型计算拟合新的实验数据,在该核区沿同中素和同位素链,并随自旋和激发能变化各自由度,跟踪原子核形状渐进变化,获得了新的系统性研究成果,显著扩展和深化了人们对原子核形状变迁和形状共存的认知。对于Ru 及其上的Rh (Z = 45), Pd (Z = 46), Ag (Z = 47) 和Cd (Z = 48) 丰中子同位素的研究表明:Rh 丰中子核具有比最大值稍小的三轴形变,γ = 28°,并在103{106Rh 同位素链上鉴别出了手征对称破缺;在三轴形变核112Ru和114Pd(N = 68)中发现了三轴原子核的摆动运动,该摆动运动也可能在114Ru (N = 70)中存在;观察到了从具有最大三轴形变的110,112Ru 中手征破缺到稍小三轴形变的112,114,116Pd 中扰动的手征破缺的过渡;在较软的Ag 核中观察到了丰富的谱学结构,在104,105Ag 中鉴别出了可能的手征对称破缺,在较重的115,117Ag 中提出了趋于三轴形变的软度;具有小形变的Cd核的能级结构被解释为准粒子耦合、准转动和软三轴形变;最近的库伦激发的研究提供了Z = 50, N = 82满壳附近122,124,126Cd 核中出现核集体性的实验和理论证据;上述研究成果展现出从Ru中的最大三轴形变(γ=30°,三轴形变极小增益为0.67 MeV), 经具有大三轴形变的Rh核γ=28°),到Pd核中的稍小、但稳定于中等自旋到高自旋区的三轴形变(γ~41°,三轴形变极小增益为0.32 MeV),再经Ag核中的软度,最后到具有很小形变、但仍出现集体性质、包括软三轴形变的Cd核的过渡。对于Pd核转动带交叉系统性的研究揭示了其第一带交叉(νh_11/2)2 中子转动顺排的上行驱动,和第二带交叉(πg_9/2)2质子转动顺排的下行驱动效应,成功地解释了114Pd 中的三轴摆动运动,并给出了110-118Pd同位素链中理论早已预言、而比早期理论预言更为完整准确的形状渐进变迁和形状共存的图像。根据该核区的系统研究,发现最大三轴形变出现在112Ru,而在相邻的偶Z(Pd)同位素链,三轴形变极小的中心在114Pd, 两者均为N = 68。上述系统性研究沿相邻的Ru和Pd偶Z同位素链,在N =68同中素中鉴别出最大三轴形变,均比理论预言的108Ru 和110Pd 多4个中子。在Z值位于Ru (Z = 44) 之下的Zr (Z = 40), Nb (Z = 41), Mo (Z = 42) and Tc (Z = 43) 丰中子同位素中,Y和Zr核具有很强的轴对称四极形变,而在较重的Zr同位素中出现了自由度;较重的Nb核(A = 104~106) 基态具有中等程度的软三轴形变和强四极形变,随着自旋和激发能的增加,过渡到接近于轴对称的强四极形变;而较轻的Nb核(A≤103) 基态均接近轴对称形状;在Nb同位素链上基态由球形到强四极形变的形状突变发生在100Nb(N = 59),在100-106Nb同位素链中基态的软三轴形变随中子数增加而增加;在Nb核中还观察到关于软三轴形变的形状共存;Mo核具有大的三轴形变,观察到了振动和手征对称破缺;Tc核具有比最大值稍小的三轴形变,γ=26°,并观察到了手征对称破缺。质子数Z从41到48的A~(100~126)丰中子同位素,特别是Pd和Nb 同位素,呈现出关于三轴形变的过渡特征。This paper reviews the systematic investigations and understanding for the shape transitions and coexistence with regard to triaxial deformations in A s 100 to 126 neutron-rich Rh (Z = 45), Pd (Z = 46), Ag (Z = 47), Cd (Z = 48) and Zr (Z = 40), Nb (Z = 41), Mo (Z = 42), Tc (Z = 43) isotopes with Z beyond and below Ru (Z = 44), respectively, in Ru the maximal triaxial deformation having been predicted and deduced. The recent measurements and studies of prompt triple- and four-fold, γ-γ-γ and γ-γ-γ-γ, coincidence data from the spontaneous fission of 252Cf using Gammasphere have yielded considerable expansion and extension or first observation of the bands in Ru, Pd, Cd, and Nb isotopes,which provided important data for the studies of nuclear shapes in this region. Combined with previous investigations, recent systematic studies of the new data well reproduced by PES, TRS, PSM, CCCSM and SCTAC model calculations have traced shape changes along the isotonic and isotopic chains, respectively,and with changing excitations/spins as well, significantly expanding our knowledge of shape transitions/coexistence in nuclei.For the neutron-rich Ru and beyond, Rh, Pd, Ag and Cd isotopes, triaxial deformations γ= 28°,slightly smaller than the maximal value, were deduced in Rh (Z = 45) isotopes, with chiral symmetry breaking proposed in 103-106Rh; onset of wobbling motions were identified in 112Ru and 114Pd (N =68),and probably also in 114Ru (N =70); evolution from chiral symmetry breaking in 110,112Ru with maximal triaxial deformations to disturbed chirality in 112,114,116Pd with less pronounced triaxial deformations was proposed; rich nuclear structure was proposed in soft Ag isotopes with possible chiral doubling structure suggested in 104,105Ag, and softness towards triaxial deformation proposed in heavier 115,117Ag;quasi-particle couplings, quasi-rotations and soft triaxiality were suggested in Cd (Z =48) isotopes with small deformations; onset of collectivity was recently suggested in 122,124,126Cd in the vicinity of Z =50 and N = 82 closed shells by studies of Coulomb excitations; shape evolutions from maximal triaxial deformations in Ru (γ=30°, with triaxial minimum energy gain of 0.67 MeV), through Rh with large triaxial deformations ( γ=28°), to less pronounced triaxiality in Pd (with triaxial minimum energy gain of 0.32 MeV), then soft triaxiality in Ag, and finally to slightly deformed Cd isotopes but with emergence of collectivity and soft triaxiality were proposed. The systematic studies of the band crossings in Pd revealed up-rising drivings of the first band crossings caused by (νh_11/2)2 and down-sloping drivings of the second band crossings by (πg_9/2)2, explained the onset of wobbling motions in 114Pd,and showed a long-sought picture of shape evolution and coexistence in the Pd isotopic chain which is more complete but complex than earlier predictions. Based on the systematic studies in the mass region,maximal triaxial deformation is found to be reached in 112Ru and less-pronounced triaxiality centered at 114Pd, both for N =68, four neutrons more than predicted in earlier theoretical calculations.In the neutron-rich Zr (Z =40), Nb (Z =41), Mo (Z =42) and Tc (Z =43) isotopes with Z just below Ru, large quadrupole deformations of axially symmetric shapes were deduced in Y and Zr isotopes, with emergence of the degree of freedom having been suggested for heavier Zr isotopes; medium triaxial deformations were deduced for the ground states of heavier (A > 104) Nb isotopes, and, with increasing excitations and spins, evolution from medium triaxial deformations with strong quadrupole deformations at ground states to nearly axially-symmetric shapes were deduced; light Nb isotopes (A6103) have near axially-symmetric shapes with strong quadrupole deformations; combining with the identification of onset of strong quadrupole deformation at 100Nb in the Nb isotopic chain, an increase of soft triaxiality with increasing neutron number was proposed in 100-106Nb. Shape coexistence with regard to soft triaxiality is also proposed in Nb isotopes; large triaxial deformations, vibrations and chiral doublets were proposed in Mo isotopes; chiral doubling and large triaxial deformations (γ ~26°) slightly smaller than the maximal triaxiality were suggested in Tc isotopes.The neutron-rich nuclei with Z ranging from 41 through 48 and A ~100 to 126, especially the Pd and Nb isotopes are thus found to be transitional nuclei with regard to triaxiality.     

光学表面非均匀中频误差的评价与修正

针对光学元件使用过程中中频误差将导致光学元件的激光破坏这一问题,提出一种中频误差突出频率提取方法。采用基于统计学的多样本数据处理,对于每一种采样方向都可以得到数个较为突出的不合格频率。利用这些频率进行确定性加工后,在特定方向,空间频率0.044 1 mm-1,0.085 8 mm-1,0.041 7 mm-1所出现的不合格次数分别降至加工前的23.9%,18.3%,29.2%,而整体中频误差减少至50.1%。结果表明,此方法降低了由光学表面中频误差方向性与局部性引起的不确定性。     

CO+分子离子彗尾带系在近红外区域的光谱研究

CO 分子离子是一种重要的瞬态自由基分子,许多研究者对该带系进行了大量的研究。文章采用光外差-磁旋转-速度调制光谱技术测量了12C16O 分子离子彗尾带系(A2Πi-X2Σ )在近红外区域的3个支带(0,3),(1,4)和(3,6)的振转吸收光谱。利用最小二乘法拟合,得到了上态A2Πi(ν′=0,1,3)的精确的分子常数。进一步验证了光外差-磁旋转-速度调制光谱技术在吸收光谱测量中的优越性。     

番茄苗期叶位色素含量高光谱检测及可视化研究

叶片色素含量是表征作物栽培基质营养元素和生理状态的重要指标;快速、精准获取色素含量及叶位分布规律是设施农业水肥精准化管理的基础。以番茄苗期不同叶位叶绿素a(Chla)、叶绿素b(Chlb)、叶绿素(Chll)和类胡萝卜素(Caro)为研究指标,用营养液配制10个氮素浓度;根据叶片位置摘取1 710片(285个样本)用于可见光-近红外高光谱采集;运用卷积平滑(S-G)、标准正态变量变换(SNV)和多元散射校正(MSC)对光谱数据预处理。首先采用竞争自适应加权算法(CARS)对特征波段“粗”提取,然后利用迭代和保留信息变量算法(IRIV)判断“粗”提取波段的重要性,并对强弱波段组逆向消除“精”提取最优波段集合,建立偏最小二乘回归(PLSR)模型。结果表明：(1)营养液氮素浓度为302.84 mg·L^-1,叶片色素含量最大,且高浓度的抑制作用高于低浓度,叶位色素含量呈上叶位>中叶位>低叶位分布规律;(2)采用CARS-IRIV-PLSR算法“粗-精”特征波段筛选策略分别对Chla、 Chlb、 Chll和Caro提取了4、 4、 10和11条特征波段,其R<...