Lasing without population inversion in molecules

We have described here the physical basis for lasing without population inversion (LWOPI). This type of amplification is obtained basically by two mechanisms: (i) one is based on atomic interference and (ii) the other is based on Fano-type interference. We have shown here, in H₂ molecules, amplification without population inversion is feasible by considering both the mechanisms.     

Qualitative and quantitative analysis of voice onset by means of a multidimensional voice analysis system (MVAS) using high-speed imaging

High-speed filming is one of the most informative methods for assessing voice physiology data. Tracing high-speed images of the glottis provides quantitative parameters such as the glottal area and the glottal width function. By way of example, a number of studies are discussed which extract quantitative data from high-speed images showing voice onsets. Furthermore, a new computer system (MVAS; multi-dimensional voice analysis system) is presented that synchronously displays a laryngoscopic high-speed film, the electroglottographical signal, and several acoustic analyses of the recorded voice sample. The automatic measurement of glottal width and glottal area from the laryngoscopic images is also provided. Looking at former studies and our analyses of voice onsets reveals a tremendous intersubject and even intrasubject variability (different prephonatory closure, different time span until full amplitude is reached, different open quotient).     

滤波片透过率曲线测量中棱镜单色仪参数的选取

从理论上分析了入射、出射狭缝大小对出射光的光谱宽度和透过率曲线的影响，得到了入射、出射狭缝大小的最佳匹配条件，并通过实验验证了这一结论，分析了鼓轮每次转动格数对测得的透过率曲线的影响，给出了鼓轮每次转动的最佳格数值．     

Bit-rate Flexible Picosecond Pulse Width Conversion with All-optical Mono-stable Multivibrator Laser Diode

An optical mono-stable multivibrator laser diode (MM-LD) is realized by using a multi-electrode distributed feedback laser diode. All-optical pulse-width conversion of ultra-short pulses to non-return-to-zero (NRZ) is achieved using an MM-LD. The MM-LD is adopted for a wide range of bit-rates between 2-10 Gbit/s by tuning the DC bias. Data format transformation from 10-Gbit/s return-to-zero optical signals to NRZ optical-signals is achieved with error free operation. Converted optical signals, which have a narrower spectral bandwidth and lower peak power than when input, are transmitted using a 1.3-μm zero dispersion fiber (1.3Aλ₀-SMF).     

The membranous contact quotient: A new phonatory measure of glottal competence

The membranous contact quotient (MCQ) is introduced as a measure of dynamic glottal competence. It is defined as the ratio of the membranous contact glottis (the anterior-posterior length of contact between the two membranous vocal folds) and the membranous vocal fold length. An elliptical approximation to the vocal fold contour during phonation was used to predict MCQ values as a function of vocal process gap (adduction), maximum glottal width, and membranous glottal length. MCQ is highly dependent on the vocal process gap and the maximum glottal width, but not on vocal fold length. Five excised larynges were used to obtain MCQ data for a wide range of vocal process gaps and maximum glottal widths. Predicted and measured MCQ values had a correlation of 0.93, with an average absolute difference of 9.6% (SD = 10.5%). The model is better at higher values of MCQ. The theory for MCQ is also expressed as a function of vocal process gap and subglottal pressure to suggest production control potential. The MCQ measure is obtainable with the use of stroboscopy and appears to be a potentially useful clinical measure.     

用光电法测量刚体的转动惯量──对波纹法测量刚体转动惯量的改进

用Ｊ─ＬＤ２转动惯量测试仪的波纹法测试转动惯量的实验方法，测量精度差，操作不方便．利用实验室现有的仪器改进成光电法测试转动惯量的方法，简单易行，测量精度高，操作方使，实践效果良好．     

AVERAGE σ-K WIDTH OF CLASS OF Lp（R^n） IN Lq（R^n）

ＡＶＥＲＡＧＥ　σ－Ｋ　ＷＩＤＴＨ　ＯＦ　ＣＬＡＳＳ　ＯＦ　Ｌ_ｐ（Ｒ~ｎ）ＩＮ　Ｌ_ｑ（Ｒ~ｎ）ＡＶＥＲＡＧＥσ－ＫＷＩＤＴＨＯＦＣＬＡＳＳＯＦＬ_ｐ（Ｒ~ｎ）ＩＮＬ_ｑ（Ｒ~ｎ）￥ＬＩＵＹＯＮＧＰＩＮＧＡｂｓｔｒａｃｔ：Ｔｈｅａｖｅｒａｇｅσ－Ｋｗｉｄｔ...     

Grid method: Application to the characterization of cracks

In this paper we present an application of the grid method to the assessment of crack initiation and growth in brittle materials. It is shown that a grid deposited on the surface of a structure can be utilized to characterize the crack location and opening. Furthermore, one single picture only is required to carry out a control over a predefined area. First, the principle of the method is introduced, showing that a periodical pattern encoding a cracked surface can be analyzed by signal processing. The phase modulation of the grid can be calculated very accurately for any small deformation of the structure. Discontinuities due to cracks are easily detected on the phase field and the crack width is proportional to the amplitude of the discontinuity. Secondly, the performances of the method are presented, mainly depending on the spatial frequency of both the pattern and the sampling. It is shown that good results can generally be obtained with few setting difficulties and equipment investment. Finally, we sum up some basic recommendations for the practical use of the technique.     

铷蒸气密度对光抽运讯号的影响

在铷蒸气密度为1×10~(10)～3.4×10~(11)cm~(-3)的范围内,测量了光抽运讯号。随着密度的增加,讯号先是增大然后减小,并在密度为5.3×10~(10)cm~(-3)时达到最大值。当密度增加到26.7×10~(10)cm~(-3)时,讯号出现负值。     

利用光纤和F-P标准具测量激光的波长和谱线宽度

本文提出了用光纤传输激光进行Ｆ－Ｐ标准具实验的方法，测量了激光的波长和谱线宽度．