Low-temperature measurements of HCN broadened by N2 in the 14-μm spectral region

Half-width and pressure-induced shift coefficients; the temperature-dependence exponents of the half-widths and the temperature-dependence coefficients of pressure-induced shifts have been measured for N₂-broadened transitions in the ν₂ band of HCN. Line positions and intensities were also determined. A total of 34 laboratory absorption spectra, recorded at 0.002-0.005 cm⁻¹ resolution with two different Fourier transform spectrometers, were used in the determination of the spectral line parameters. The total pressures of the HCN-N₂ samples ranged from less than 1 torr up to nearly 1 atm, and temperatures were between 211 and 300 K. A multispectrum nonlinear least-squares fitting technique employing a modified Voigt line profile, including speed dependence and line mixing via the off-diagonal relaxation matrix formulation, was used in the analysis. Speed-dependence parameters were determined in the P and R branches of the ν₂ band of H¹²C¹⁴N, and in the ν₂ Q branches of H¹²C¹⁴N and H¹³C¹⁴N the off-diagonal relaxation matrix elements that characterize line mixing were included in the analysis to fit the data. Present results are compared with previous measurements reported in the literature.     

Determining a 'safe' high-mass limit in matrix-assisted laser desorption/ionisation time-of-flight mass spectra of coal derived materials with reference to instrument noise

Three methods for determining a 'safe' estimate for high-mass limits of MALDI spectra of coal derived liquids were explored, using a sample of coal-tar pitch and its pyridine-insoluble fraction. Co-addition of increasing numbers of single-shot spectra (10, 30, 50 and 100 pulses) showed visually observable reductions in noise levels, consistent with robust and statistically meaningful signals. Three separate types of post-acquisition calculation were used to identify high-mass limits of the spectra. (i) A literature method indicated high-mass limits similar to those observed visually-as a shift from baseline at the highest masses, nearly 350 000 u for the coal tar pitch and about 390 000 u for its pyridine insoluble fraction. (ii) Comparing instrument signal with pre-selected multiples of the standard deviation, upper mass estimates of between 40-60 000 u for the coal-tar pitch and about 95 000 u for its pyridine-insoluble fraction were found. (iii) Calculation of the slope was used to identify 'lift-off' of the spectrum from baseline. The angle between the smoothed spectrum and the baseline was matched to a pre-selected value (e.g. 0.5 degrees and 1 degrees ). However, the arbitrary specification of the key parameter did not establish this last method on a firm basis. The choice of a criterion for estimating high-mass limits of MALDI spectra remains a semi-quantitative procedure; a reasonably conservative high-mass limit may be estimated by comparison of signal with five times the standard deviation. However, evaluation of size exclusion chromatograms of the present samples using polystyrene standards suggests that molecular mass distributions of pitch samples arrived at by MALDI mass spectrometry are, at least partly, determined by the limitations of available instruments. Copyright 1999 John Wiley & Sons, Ltd.     

158 A Ge V p-Pb Pb-Pb碰撞中的单奇异和多奇异粒子产生

用描写相对论性核 核碰撞的LUCIAE模型及相应的MonteCarlo事例产生器分析了WA97最近发表的 1 5 8AGeVp Pb和Pb Pb碰撞中单奇异粒子 (Λ ,Λ)和多奇异粒子 (Ξ-,Ξ-,Ω-,Ω-)的多重数和横质量分布 .由于LUCIAE模型包含了弦碎裂微观过程中奇异夸克压低因子随碰撞体系的能量、中心度和质量的增大而增大 ,以及由它导致的相对论性核 核碰撞宏观过程中奇异粒子产额随上述三因素之增而增的物理机制 ;LUCIAE模型计算结果能较好描写WA97实验所揭示的相对论性核 核碰撞中奇异粒子产额随中心度之增而增和奇异粒子增强随奇异夸克数之增而增的实验事实 ,以及单奇异和多奇异粒子的横质量分布 .     

The effect of topical anesthesia on vocal fold motion

The objective of this study was to determine if topical anesthesia to the larynx and pharynx affects vocal fold motion during dynamic voice evaluation with transnasal flexible endoscopy. Transnasal dynamic laryngeal examinations of 10 patients with no voice complaints were evaluated by five blinded fellowship-trained laryngologists. Each patient was examined before and after application of topical anesthetic. Reviewers rated briskness of right and left vocal fold movement and longitudinal tension on a visual analogue scale. Statistical comparisons were made between individual subject scores before and after anesthetic application. Inter-rater reliability was also assessed. No statistical difference was observed between subject scores before and after anesthetic application. Average intraclass correlation coefficients were 0.643 and 0.591 for pre- and postanesthesia scores, respectively. Application of topical anesthesia to the larynx and pharynx does not affect vocal fold motion.     

Line intensities for the ν1, ν3 and ν1+ν3 bands of 34SO2

Using both high resolution (0.0018 cm^?1) and medium resolution (0.112 cm^?1) Fourier transform spectra of an enriched ³⁴S (95.3%) sample of sulfur dioxide, it has been possible to accurately measure a large number of individual line intensities for some of the strongest of the SO₂ bands, i.e. ν₁, ν₃ and ν₁₊ν₃. These intensities were least-squares fitted using a theoretical model which takes into account the vibration–rotation interactions linking the upper energy levels where needed, and, in this way, expansions of the various transition moment operators were determined. The Hamiltonian parameters determined in previous analyses together with these moments were then used to generate synthetic spectra for the bands studied and their corresponding hot bands providing one with an extensive picture of the absorption spectrum of ³⁴SO₂ in the spectral domains, 8.7, 7.4, and 4 μm.     

Hartree-Fock-Bogoliubov calculations of the rotational band of the very heavy 254No nucleus

We report on Hartree-Fock-Bogoliubov (HFB) calculations of the ground-state rotational band of the heavy nucleus ²⁵⁴No recently observed experimentally. The calculated quadrupole deformation is consistent with the experimental value of β = 0.27 and is almost constant over the whole band. We also reproduce fairly well the excitation spectra and moments of inertia of this isotope up to the maximal experimentally observed state of spin 20. The rather high stability of this nucleus against fission is illustrated by the deformation energy curve providing very high fission barriers at zero spin within the HFB and HFB plus Lipkin-Nogami formalisms. The variation of these barriers with increased angular velocities is also studied. Received: 23 November 2000 / Accepted: 24 October 2001     

叶绿体结构和功能的研究——叶绿体残缺膜与线粒体嵴膜组合光合磷酸化活力的重建

本文证明了类囊体残缺膜可以与线粒体嵴膜组合而成为新囊膜。这种膜组织可以通过嵴膜的偶联因子借光能来进行光合磷酸化。电子显微镜图谱显示,这种膜组织是介乎残缺膜与嵴膜之间一种膜组织。 试验结果支持了这样一种观点,即:叶绿体内光合磷酸化与线粒体内氧化磷酸化的磷酸化机构是一致的,其细胞器可能是有着共同的来源。     

关于平面二次系统的极限环

关于常微分方程二次系统的极限环及分布结构,本文得到下述定理: 设有一个三阶细焦点,并且无限远奇点是唯一的简单的奇点,则必存在另外一个粗焦点。在粗焦点外有奇数个极限环,无限远奇点为鞍点,全局结构已定。 在上述的基础上对方程作参数的微小变化,使三阶细焦点跳出三个极限环,则得二个粗焦点,每个外面有奇数个极限环,总极限环数为偶数个,并至少为4个,全局结构已定。     

Supersonic free-jet quantum cascade laser measurements of ν4 for CF3Cl and CF3Cl and FTS measurements from 400 to 1260 cm

A supersonic free-jet spectrum of the ν₄ band of CF₃Cl has been measured using a quantum cascade laser system. Those measurements were combined with a low temperature (−67 °C) FTS spectrum of the region 1060-1260 cm⁻¹ and with room temperature FTS measurements down to 400 cm⁻¹ to give improved values for the rovibrational constants for the ν₁, ν₂, ν₃, 2ν₃, 2ν₅, ν₄, and ν₅ states of CF₃³⁵Cl and CF₃³⁷Cl. The principal perturbation found by earlier investigators in the ν₁ band is treated as a very weak Coriolis interaction at several avoided crossings of the rotational levels of the ν₁ state and the 2ν₅ state with kl < 0. None of the other vibrational states showed any signs of perturbations. With these new measurements we now have high resolution data on all of the fundamental vibrational states except ν₆.