成年口吃者流畅朗读中塞音的声学分析

研究对成年口吃者在流畅朗读过程中的塞音进行了声学分析,测量了嗓音起始时间并且计算了塞音爆破时刻的频谱矩,并将口吃者在言语矫治前后与非口吃者进行了对比。多因素方差分析结果显示,口吃者嗓音起始时间虽稍长于非口吃者但未达到统计意义上的显著性差异水平,而且受发音部位和韵母的影响程度较大。同时还观察到矫治前口吃者和非口吃者在塞音爆破段的频谱均值呈现出显著性差异,口吃者频谱均值低于非口吃者可能是由于口吃者舌与齿龈或软硬腭形成阻塞的部位在声道中偏后所导致,还发现口吃者韵母对塞音爆破段频谱的影响较小,此结果表明口吃者表现出相对较弱的协同发音现象。口吃者经过言语矫治后塞音的嗓音起始时间和爆破段频谱有向非口吃者逼近的趋势。     

Theoretical analysis of the performance of a single side band multicarrier source based on a re-circulating frequency shifter influenced by an optical bandpass filter

An optical bandpass filter （OBF） is an important element whose properties considerably influence the output performance of a single side band multicarrier source based on a re-circulating frequency shifter. The influence of the OBF in the loop on the output spectrum is theoretically analyzed. Numerical simulations and experiments are Mso carried out. Results show that the steepness and deepness of a nonflat-top filter influence the stability of the spectrum of an output multicarrier. To obtain multicarrier output with tone to noise ratio （TNR） 〉26 dB and error vector magnitude （EVM） 〈0.25, the steepness ratio of the filter should be greater than 0.75 and deepness should be larger than 0.99.     

基于变压红外光谱研究离子液体[MPIM][I]与石墨烯氧化物之间的相互作用

本研究利用红外光谱研究不同压力下离子液体1-Methy1-3-propylimidazolium iodide([MPIM][I])与石墨烯及其氧化物的相互作用.结果表明,[MPIM][I]对压力的变化具有高敏感度,咪唑环与烷基链在0.4 GPa时产生相变化,可明显观察到吸收峰的裂解,且连续加压会导致咪唑环与烷基链的振动频率蓝移.[MPIM][I]与石墨烯作用时加压至2.5 GPa也未观测到相变化的产生,且咪唑环与烷基链的振动频率蓝移趋势也不明显;[MPIM][I]与石墨烯氧化物作用时咪唑环与烷基链的结果与添加石墨烯时几乎相同.石墨烯氧化物具有羟基、羧基、环氧基等共价键结在其表面,这些羟基会扰动[MPIM][I]中的咪唑环与烷基链,导致在常压下振动频率发生蓝移,进而表明石墨烯表面的官能基团会与离子液体产生相互作用.     

"理科综合能力测试"之我见

随着高考制度的改革,越来越多的省市已实行了"3+X"考试,面对"X"中的"理科综合能力测试"(以下简称"理综")物理教学应如何进行改革的问题已引起越来越多物理教师的关注.以下对此问题谈几点看法.     

A design of novel type superconducting magnet for super—high field functional magnetic resonance imaging by using the harmonic analysis method of magnetic vector potentials

The approach of expanding the magnetic scalar potential in a series of Legendre polynomials is suitable for designing a conventional superconducting magnetic resonance imaging magnet of distributed solenoidal configuration. Whereas the approach of expanding the magnetic vector potential in associated Legendre harmonics is suitable for designing a single-solenoid magnet that has multiple tiers, in which each tier may have multiple layers with different winding lengths. A set of three equations to suppress some of the lowest higher-order harmonics is found. As an example, a 4T single-solenoid magnetic resonance imaging magnet with 4×6 layers of superconducting wires is designed. The degree of homogeneity in the 0.5m diameter sphere volume is better than 5.8 ppm. The same degree of homogeneity is retained after optimal integralization of turns in each correction layer. The ratio B_m/B₀ in the single-solenoid magnet is 30% lower than that in the conventional six-solenoid magnet. This tolerates higher rated superconducting current in the coil. The Lorentz force of the coil in the single-solenoid system is also much lower than in the six-solenoid system. This novel type of magnet possesses significant advantage over conventional magnets, especially when used as a super-high field functional magnetic resonance imaging magnet.     

尾式铁(Ⅲ)卟啉的合成及其光谱性质研究

合成了不同侧链长度的苯并咪唑基尾式卟啉及其Fe（Ⅲ）配合物。化合物经质谱、^1HMR、UVVisible、IR等表征，表明苯并咪唑基与卟啉环通过醚氧键和醚硫键相连。光谱学研究表明侧链较短不利于尾端基团的配位，长度对尾端基团的配位起着重要作用。     

武定恐龙化石的显微拉曼光谱研究

本文首次利用激光显微拉曼光谱、原子光谱和偏光显微镜等方法 ,对云南武定的恐龙化石进行了分析研究。实验发现 ,恐龙化石表面和截面的拉曼光谱 ,均为典型的方解石 (CaCO3 )晶体的拉曼谱 ,并未发现有其他成分的拉曼谱。原子发射光谱的分析结果表明 ,恐龙化石中的主要元素有Ca(>10 % ) ,其次是Si(5 0 % )和P(4 0 % ) ,还有Fe(1 0 % )等 ,但未发现铱、钍等稀有元素。由恐龙化石截面在偏光显微镜下的图像可以知道 ,恐龙化石表面层的成分主要是方解石晶体 ;内部的主要成分为方解石 (CaCO3 )晶体 ,此外还有纤维状一水二氧化硅 (分子式SiO2 ·nH2 O ,属非晶态 )等成分。激光拉曼光谱能快速无损地准确检测出恐龙化石的主要成分是方解石 (CaCO3 ) ,拉曼光谱对恐龙化石的分析结果与原子光谱、偏光显微镜的分析结果是一致的     

氮化铝结构的高温Raman光谱分析

本文测量了氮化铝在不同温度下的Raman光谱 ,并确定了氮化铝的光学声子模E2 1、A1(TO)、E2 2 、E1(TO)、A1(LO)和E1(LO)Raman散射峰的频率 ,它们分别为 2 5 2cm- 1、6 1 4cm- 1、6 5 8cm- 1、6 72cm- 1、894cm- 1和 91 2cm- 1,其中光学声子模A1(TO)、E2 2 的Raman散射峰比较明显。随着温度的升高 ,A1(TO)、E2 2 散射峰的频率向低波数方向变化 ,表明氮化铝粉末压制体中存在的压应力逐渐减小 ;这两个散射峰的半高宽逐渐增大 ,说明随着温度的升高 ,存在氮原子和铝原子的扩散使得氮化铝粉末压制体中晶体结构逐渐发生变化。由于氮化铝粉末本身在空气中易与水蒸气发生反应 ,生成的Al(OH) 3 或AlOOH在加热过程会发生分解 ,干扰样品高温Raman光谱测量。     

HIRFL 高频相位与幅度稳定系统

介绍了兰州重离子研究装置(HIRFL) 主回旋加速器(SSC) 高频系统高频电压的相位稳定与幅度稳定系统,重点介绍了设备的组成和稳定环路设计以及正交变换与稳定环路滤波器的设计方法。通过在SSC 腔体上进行的长期的现场测试,得到了调制抑制度与长期稳定度的测试方法,并对结果进行了分析。其中,设备的长期相位稳定度达到0:014°,长期幅度稳定度达到1.29x10-4,远高于改造前的指标。The phase and amplitude stabilization system of high-frequency voltage on the main cyclotron SSC of Heavy Ion Research Facility in Lanzhou (HIRFL) is introduced. The system composition, negative feedback loop design and other important aspects about the development of the system are particularly presented in this paper. Designing method of digital PLL orthogonal transformation and loop filter of phase and amplitude stabilization are introduced in detail. Control systems of SSC have been tested through a long-term stability experiments, the test method of the parasitic modulation suppression and stabilization in long term is proposed. According to the analyzing data, it shows that phase control accuracy in long term is within 0:014° and the amplitude deviation in long term is lower than 1.29x10-4. Compared with the traditional system, its capability and target is much better.