Parabolic subgroups in FC-type Artin groups

Parabolic subgroups are the building blocks of Artin groups. This paper extends previous results of Cumplido, Gebhardt, Gonzales-Meneses and Wiest, known only for parabolic subgroups of finite type Artin groups, to parabolic subgroups of FC-type Artin groups. We show that the class of finite type parabolic subgroups is closed under intersection. We also study an analog of the curve complex for mapping class group constructed by Cumplido et al. using parabolic subgroups. We extend the construction of this complex, called the complex of parabolic subgroups, to FC-type Artin groups. We show that this simplicial complex is, in most cases, infinite diameter and conjecture that it is δ-hyperbolic.     

对光谱快速定量分析的探讨

通过固定光谱校准曲线,压缩光谱谱带间隙,可降低测试成本,工作效率提高1.5倍,分析质量准确可靠.     

荧光光纤光栅传感特性的实验研究

在载氢掺铒光纤上写入Bragg光纤光栅，得到新型光子学器件-荧光光纤光栅.分别对其Bragg波长（λB）及荧光寿命（τ）的温度（T）及应变（ε）响应特性进行了实验研究，并且给出了λB和τ分别关于（T，ε）的拟合方程.实验结果表明：荧光光纤光栅的λB对T和ε的响应具备一般Bragg光纤光栅的优良特性，测得温度灵敏度为11.1pm /℃，应变灵敏度为1.19pm/με；而且τ对T和ε的响应也具有良好的线性关系，温度灵敏度为0.59 μs/℃，应变灵敏度为6.16 ns/με.实验结论为解决温度应力交叉敏感、实现温度应力的同时监测提供一条新颖的途径.     

Thermoanalytical characterization of carbon/carbon hybrid material, Apple Woodceramics

Woodceramics, a carbon/carbon composite of plant-originated carbon reinforced by glassy carbon from phenolic resin, was prepared from apple pomace at carbonizing temperatures of 1073 K (AWC800) and 1473 K (AWC1200), and characterized by thermoanalytical methods and X-ray diffraction (XRD). Simultaneous differential scanning calorimetry (DSC) and thermogravimetric (TG) showed complicated overlapping reactions similar to those of coal. The initial temperature of pyrolysis was obtained by fitting logistic functions to observed TG data. The results suggested that AWC1200 contained more volatile matter than AWC800. In an inert atmosphere, complicated devolatilization takes place. In an oxidizing atmosphere, thermal change occurs roughly in four steps: desorption of physically adsorbed matter; pyrolysis into aliphatic and aromatic fragments; ignition; combustion of char. The oxidation resistance of AWC1200 was superior to AWC800.     

Multivariate resolution of NMR labile signals by means of hard- and soft-modelling methods

One of the difficulties frequently encountered when studying acid–base equilibria with NMR spectroscopy is the labile behaviour of the measured signal, which hinders the application of bilinear multivariate data analysis methods. In this work, a mathematical transformation is proposed for the conversion of NMR labile signals to inert signals, which make possible the application of multivariate data analysis methods, based on bilinear data models. The procedure has been applied to the analysis of NMR data corresponding to the acid–base equilibria of nucleotides dCMP and dGMP. Both hard-modelling (EQUISPEC) and soft-modelling (MCR-ALS) approaches have been applied for the analysis and resolution of transformed bilinear NMR data matrices.     

Mixing of electronic states in molybdenum complexes involved in nitrogen activation

The mechanism for nitrogen activation by molybdenum complexes is a complicated one, involving as it does the coupling of a quartet molybdenum reactant with a singlet nitrogen molecule, passing via a series of quartet and doublet encounter complexes to a triplet intermediate, with the subsequent spin crossing to the singlet surface which then leads via a singlet transition state to the final pair of singlet products. We have investigated in detail a variety of levels of theory to describe the crossing of these electronic surfaces and have calculated both lower-bound and actual minimum energy crossing points for the key spin inversion processes.     

溶剂蒸气对聚对苯二甲酸乙二酯作用的差示扫描量热研究

用差示扫描量热(DSC)研究了几种有机溶剂蒸气对聚对苯二甲酸乙二酯(PET)的作用,表明可分为反应性的和非反应性的两种。同时,对于非反应性的作用,依冷结晶峰面积的变化,又可分为三种类型:冷结晶峰面积不变,经诱导期后下降,无诱导期而迅速下降。双冷结晶峰现象在一些非反应性溶剂处理过的PET试样的DSC曲线也观察到。     

Valence Bond Study of Dissociation Behavior and Spectroscopic Constants for the Ground States of LiF and NaF

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Extension and application of multivariate curve resolution-alternating least squares to four-way quadrilinear data-obtained in the investigation of pollution patterns on Yamuna River,India—A case study

This study focuses on the development and extension of Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) to the analysis of four-way datasets. The proposed extension of the MCR-ALS method with non-negativity and the newly developed quadrilinear constraints can be exploited to summarize and manage huge multidimensional datasets and resolve their four way component profiles. In this study, its application is demonstrated by analyzing a four-way data set obtained in a long term environmental monitoring study (15 sampling sites × 9 variables × 12 months × 7 years) belonging to the Yamuna River, one of the most polluted rivers of India and the largest tributary of the Ganges river. MCR-ALS resolved pollution profiles described appropriately the major observed changes on pH, organic pollution, bacteriological pollution and temperature, along with their spatial and temporal distribution patterns for the studied stretch of Yamuna River. Results obtained by MCR-ALS have also been compared with those obtained by another multi-way method, PARAFAC. The methodology used in this study is completely general and it can be applied to other multi-way datasets.     

Muscle oxygenation measurement in humans by noninvasive optical spectroscopy and Locally Weighted Regression

We have developed a method to make real-time, continuous, noninvasive measurements of muscle oxygenation (Mox) from the surface of the skin. A key development was measurement in both the visible and near infrared (NIR) regions. Measurement of both oxygenated and deoxygenated myoglobin and hemoglobin resulted in a more accurate measurement of Mox than could be achieved with measurement of only the deoxygenated components, as in traditional near-infrared spectroscopy (NIRS). Using the second derivative with respect to wavelength reduced the effects of scattering on the spectra and also made oxygenated and deoxygenated forms more distinguishable from each other. Selecting spectral bands where oxygenated and deoxygenated forms absorb filtered out noise and spectral features unrelated to Mox. NIR and visible bands were scaled relative to each other in order to correct for errors introduced by normalization. Multivariate Curve Resolution (MCR) was used to estimate Mox from spectra within each data set collected from healthy subjects. A Locally Weighted Regression (LWR) model was built from calibration set spectra and associated Mox values from 20 subjects using 2562 spectra. LWR and Partial Least Squares (PLS) allow accurate measurement of Mox despite variations in skin pigment or fat layer thickness in different subjects. The method estimated Mox in five healthy subjects with an RMSE of 5.4%.