The appropriate bireflectance film series are selected to get thebeat-frequency of dual-frequency laser using anisotropic bireflectance film (DLABF) from 1.2 MHz to6 MHz. The maximum measurement velocity of the interf...The appropriate bireflectance film series are selected to get thebeat-frequency of dual-frequency laser using anisotropic bireflectance film (DLABF) from 1.2 MHz to6 MHz. The maximum measurement velocity of the interferometer utilizing DLABF can be up to 1.8 m/s.Generally the outputs of the DLABF in a transverse magnetic field are two orthogonalmicro-elliptical polarized components when DLABF can emit dual-frequency laser. When the laser tubeis spun in the magnetic field, the ellipticities of these two components are also changed. In somecertain relative angles, the outputs the DLABF are two almost ideally orthogonal linear polarizedcomponents. The frequency stabilization of DLABF is also discussed. The maximum variation of thebeat-frequency of the stabilized DLABF can be 0.15 kHz within 46 h. As no quarter wave plate (QWP)needed, DLABFs have better thermal stability than longitudinal Zeeman lasers.展开更多
Mathematics teaching in middle and high grades of primary schools will learn multiplication and division and related knowledge of spatial imagination. Compared with mathematics knowledge in lower grades, students spat...Mathematics teaching in middle and high grades of primary schools will learn multiplication and division and related knowledge of spatial imagination. Compared with mathematics knowledge in lower grades, students spatial imagination ability is required higher. Therefore, the mathematics teaching in the middle and high grades of primary schools should consciously infiltrate the mathematical thinking methods so as to help students better understand the mathematics knowledge they have learned. This paper focuses on the relevant measures of infiltrating mathematical thinking methods into mathematics teaching in middle and senior primary schools so as to better promote the improvement of students mathematics learning ability.展开更多
The algorithm is divided into two steps. The first step pre-locates the blank by aligning its centre of gravity and approximate normal vector with those of destination surfaces, with largest overlap of projections...The algorithm is divided into two steps. The first step pre-locates the blank by aligning its centre of gravity and approximate normal vector with those of destination surfaces, with largest overlap of projections of two objects on a plane perpendicular to the normal vector. The second step is optimizing an objective function by means of gradient-simulated annealing algorithm to get the best matching of a set of distributed points on the blank and destination surfaces. An example for machining hydroelectric turbine blades is given to verify the effectiveness of algorithm.展开更多
Background Dominantly inherited spinocerebellar ataxia (SCA) is a clinically and genetically heterogeneous group of neurodegenerative disorders. This study was to further assess the frequency of SCA1 (spinocerebellar ...Background Dominantly inherited spinocerebellar ataxia (SCA) is a clinically and genetically heterogeneous group of neurodegenerative disorders. This study was to further assess the frequency of SCA1 (spinocerebellar ataxia type 1), SCA2, SCA3/MJD (spinocerebellar ataxia type 3/Machado-Joseph disease), SCA6, SCA7, SCA8, SCA10, SCA12, SCA14, SCA17 and DRPLA (dentatorubro-pallidoluysian atrophy) in mainland Chinese, and to specifically characterize mainland Chinese patients with SCA6 in terms of clinical and molecular features.Methods Using a molecular approach, we investigated SCA in 120 mainland Chinese families with dominantly inherited ataxias and in 60 mainland Chinese patients with sporadic ataxias. Clinical and molecular features of SCA6 were further characterized in 13 patients from 4 families. Results SCA3/MJD was the most common type of autosomal dominant SCA in mainland Chinese, accounting for 83 patients from 59 families (49.2%), followed by SCA2[8(6.7%)], SCA1[7(5.8%)], SCA6[4(3.3%)], SCA7[1(0.8%)], SCA8(0%), SCA10(0%), SCA12(0%), SCA14(0%), SCA17(0%) and DRPLA(0%). The genes responsible for 41 (34.2%) of dominantly inherited SCA families remain to be determined. Among the 60 patients with sporadic ataxias in the present series, 3 (5.0%) was found to harbor SCA3 mutations while none was found to harbor SCA6 mutations. In the 4 families with SCA6, significant anticipation was found in the absence of genetic instability on transmission.Conclusion A geographic cluster of families with SCA6 subtype was initially identified in a mainland Chinese population.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50027002).
文摘The appropriate bireflectance film series are selected to get thebeat-frequency of dual-frequency laser using anisotropic bireflectance film (DLABF) from 1.2 MHz to6 MHz. The maximum measurement velocity of the interferometer utilizing DLABF can be up to 1.8 m/s.Generally the outputs of the DLABF in a transverse magnetic field are two orthogonalmicro-elliptical polarized components when DLABF can emit dual-frequency laser. When the laser tubeis spun in the magnetic field, the ellipticities of these two components are also changed. In somecertain relative angles, the outputs the DLABF are two almost ideally orthogonal linear polarizedcomponents. The frequency stabilization of DLABF is also discussed. The maximum variation of thebeat-frequency of the stabilized DLABF can be 0.15 kHz within 46 h. As no quarter wave plate (QWP)needed, DLABFs have better thermal stability than longitudinal Zeeman lasers.
文摘Mathematics teaching in middle and high grades of primary schools will learn multiplication and division and related knowledge of spatial imagination. Compared with mathematics knowledge in lower grades, students spatial imagination ability is required higher. Therefore, the mathematics teaching in the middle and high grades of primary schools should consciously infiltrate the mathematical thinking methods so as to help students better understand the mathematics knowledge they have learned. This paper focuses on the relevant measures of infiltrating mathematical thinking methods into mathematics teaching in middle and senior primary schools so as to better promote the improvement of students mathematics learning ability.
文摘The algorithm is divided into two steps. The first step pre-locates the blank by aligning its centre of gravity and approximate normal vector with those of destination surfaces, with largest overlap of projections of two objects on a plane perpendicular to the normal vector. The second step is optimizing an objective function by means of gradient-simulated annealing algorithm to get the best matching of a set of distributed points on the blank and destination surfaces. An example for machining hydroelectric turbine blades is given to verify the effectiveness of algorithm.
文摘Background Dominantly inherited spinocerebellar ataxia (SCA) is a clinically and genetically heterogeneous group of neurodegenerative disorders. This study was to further assess the frequency of SCA1 (spinocerebellar ataxia type 1), SCA2, SCA3/MJD (spinocerebellar ataxia type 3/Machado-Joseph disease), SCA6, SCA7, SCA8, SCA10, SCA12, SCA14, SCA17 and DRPLA (dentatorubro-pallidoluysian atrophy) in mainland Chinese, and to specifically characterize mainland Chinese patients with SCA6 in terms of clinical and molecular features.Methods Using a molecular approach, we investigated SCA in 120 mainland Chinese families with dominantly inherited ataxias and in 60 mainland Chinese patients with sporadic ataxias. Clinical and molecular features of SCA6 were further characterized in 13 patients from 4 families. Results SCA3/MJD was the most common type of autosomal dominant SCA in mainland Chinese, accounting for 83 patients from 59 families (49.2%), followed by SCA2[8(6.7%)], SCA1[7(5.8%)], SCA6[4(3.3%)], SCA7[1(0.8%)], SCA8(0%), SCA10(0%), SCA12(0%), SCA14(0%), SCA17(0%) and DRPLA(0%). The genes responsible for 41 (34.2%) of dominantly inherited SCA families remain to be determined. Among the 60 patients with sporadic ataxias in the present series, 3 (5.0%) was found to harbor SCA3 mutations while none was found to harbor SCA6 mutations. In the 4 families with SCA6, significant anticipation was found in the absence of genetic instability on transmission.Conclusion A geographic cluster of families with SCA6 subtype was initially identified in a mainland Chinese population.
