Effect of domain selection for compact representation of spatial variation of Head-Related Transfer Function in all directions based on Spatial Principal Components Analysis

In this article, compact representation of spatial variation of Head-Related Transfer Function (HRTF) or its corresponding inverse Fourier transform, namely Head-Related Impulse Response (HRIR) based on Principal Components Analysis (PCA), which is called the Spatial Principal Component Analysis (SPCA), is investigated, focusing on effect of domain selection. The SPCA was carried out for a database of HRTFs in all directions by selecting the domain as one of the HRIRs, the complex HRTFs, the frequency amplitudes of HRTFs, and log-amplitudes of HRTFs. In the latter two cases the minimum phase approximation was incorporated. Comparison of the accuracy in both time and frequency domains showed that the most compact representation is obtained by using the frequency amplitudes of HRTFs when the minimum phase approximation is acceptable, and the complex HRTFs bring about the most compact representation when the minimum phase approximation is not acceptable.     

藏药迷果芹脂溶性成分分析

采用气相色谱-质谱（GC-MS）联用技术对藏药迷果芹的脂溶性成分进行分析.从藏药迷果芹石油醚萃取物中分离鉴定出26种化合物,占其总量的98.77％.在已鉴定的化学成分中,含量较高的化学成分依次为亚油酸（35.90％）、芹菜脑（23.98％）、棕榈酸（11.41％）、亚油酸乙酯（4.08％）、亚油酸甲酯（4.06％）、β-谷甾醇（4.40％）.本研究为开发迷果芹资源提供了科学依据.     

玉竹不同器官挥发性成分的SPME-GC-MS法比较分析

分析和比较了玉竹不同器官中的挥发性成分的差异.采用固相微萃取/气相色谱/质谱（SPME/GC/MS）联用技术对玉竹不同器官挥发性成分进行分析,利用峰面积归一化法测定各个成分的相对百分含量.从玉竹的根、茎、叶中分别分离出28、23和26种挥发性成分,主要包括酮、烷烃、烯烃、芳香烃、醇和脂类等化合物.3种器官中挥发性成分组成及相对含量差异较大,共有成分仅为香叶基丙酮.本研究为玉竹的进一步开发利用提供了理论依据.     

Characteristics of persistent spin current components in a quasi-periodic Fibonacci ring with spin–orbit interactions: Prediction of spin–orbit coupling and on-site energy

In the present work we investigate the behavior of all three components of persistent spin current in a quasi-periodic Fibonacci ring subjected to Rashba and Dresselhaus spin–orbit interactions. Analogous to persistent charge current in a conducting ring where electrons gain a Berry phase in presence of magnetic flux, spin Berry phase is associated during the motion of electrons in presence of a spin–orbit field which is responsible for the generation of spin current. The interplay between two spin–orbit fields along with quasi-periodic Fibonacci sequence on persistent spin current is described elaborately, and from our analysis, we can estimate the strength of any one of two spin–orbit couplings together with on-site energy, provided the other is known.     

On the Numerical Range of Operator Polynomials

An upper bound for the number of components of the numerical range of matrix polynomials is established. We also establish a necessary condition and a sufficient condition for the connectedness of the numerical range of a quadratic selfadjoint matrix polynomial. The boundary of the numerical range of linear matrix polynomials is also considered.     

一种快速对高风险零部件进行RoHS检测的方法

X射线荧光光谱分析法对高风险零部件快速的RoHS检测,使用这种"快速筛选"的方法有以下两点目的:一方面审核供应商提交的有毒有害物质符合性声明的准确性,另一方面也节约企业检测成本。     

Influence of the interaction of components on the pyrolysis behavior of biomass

There has been much interest in the utilization of biomass-derived fuels as substitutes for fossil fuels in meeting renewable energy requirements to reduce CO₂ emissions. In this study, the pyrolysis characteristics of biomass have been investigated using both a thermogravimetric analyzer coupled with a Fourier-transform infrared spectrometer (TG-FTIR) and an experimental pyrolyzer. Experiments have been conducted with the three major components of biomass, i.e. hemicellulose, cellulose, and lignin, and with four mixed biomass samples comprising different proportions of these. Product distributions in terms of char, bio-oil, and permanent gas are given, and the compositions of the bio-oil and gaseous products have been analysed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography (GC). The TG results show that the thermal decomposition of levoglucosan is extended over a wider temperature range according to the interaction of hemicellulose or lignin upon the pyrolysis of cellulose; the formation of 2-furfural and acetic acid is enhanced by the presence of cellulose and lignin in the range 350-500 °C; and the amount of phenol, 2,6-dimethoxy is enhanced by the integrated influence of cellulose and hemicellulose. The components do not act independently during pyrolysis; the experimental results have shown that the interaction of cellulose and hemicellulose strongly promotes the formation of 2, 5-diethoxytetrahydrofuran and inhibits the formation of altrose and levoglucosan, while the presence of cellulose enhances the formation of hemicellulose-derived acetic acid and 2-furfural. Pyrolysis characteristics of biomass cannot be predicted through its composition in the main components.     

LC Method for the Determination of Multiple Components in a Compound Cold Formulation

An isocratic liquid chromatographic method for determination of acetaminophen (AMP), caffeine (CAF), chlorphenamine maleate (CPM) and guaiacol glyceryl ether (GGE) in a compound cold formulation is described. Separation and quantitation were achieved on a Diamonsil C18 column using a binary mixture of methanol and 1.5% aqueous acetic acid (55: 45, v/v, pH 3.6) as mobile phase delivered at 0.4 mL min^–1. Single wavelength detection was at 220 nm for all four drugs and the run time was < 10 min. The linearity, accuracy and precision of the method were found to be acceptable over the concentration ranges: 16.0–127.8 g mL^–1 for AMP, 6.0–48.2 g mL^–1 for CAF, 5.0–40.0 g mL^–1 for CPM and 10.1–80.6 g mL^–1 for GGE.     

我国城市设施水平的主成分分析

本文提出多元统计分析的一种评价方法：通过对全国31个省市自治区的城市设施水平进行主成分分析，就各地区城市设施水平进行统计评价，揭示我国城市的发展质量、城市居民的生活质量，找出各地区在设施建设各方面的优势与不足，为我国今后的城市化道路提供科学的参考依据。