Weaker connected and weaker nowhere locally compact topologies for metrizable and similar spaces

We prove that any metrizable non-compact space has a weaker metrizable nowhere locally compact topology. As a consequence, any metrizable non-compact space has a weaker Hausdorff connected topology. The same is established for any Hausdorff space X with a σ-locally finite base whose weight w(X) is a successor cardinal.     

肉苁蓉种子成分及活力的红外光谱分析

采用傅里叶变换红外光谱法(FTIR),分析研究了肉苁蓉种子不同部位及其在不同处理后的光谱特征和成分差异。结果显示,肉苁蓉种子成分组成丰富,同时存在蛋白质、脂类和碳水化合物的特征吸收峰,并且推测含有果胶质和芳香类化合物。肉苁蓉种皮和种仁的成分差异很大,2 926,1 746,1 161及721 cm-1处一系列强峰说明种仁中的油脂类成分含量非常高,而种皮中1 054 cm-1处碳水化合物和果胶质类的特征吸收峰最强。霉变或高温处理后肉苁蓉种子中与活力相关的蛋白质及糖类含量明显减少,而有活力的种子中蛋白质与脂类所在特征区域的峰高比(I_{1 630}／I_{1 745})(cm-1)均大于1.05。而肉苁蓉种仁失活后酰胺Ⅰ带与脂类特征峰的强度比值(I_{1 653}／I_{1 745})由0.31降为0.23,降幅达25.8%。研究表明,红外光谱法不仅可应用于肉苁蓉种子成分的全面快速分析,而且还可更深入应用于种子生活力、种子寿命乃至种子质量的快速分析与测定。     

Optimal single machine scheduling of products with components and changeover cost

We consider the problem of scheduling products with components on a single machine, where changeovers incur fixed costs. The objective is to minimize the weighted sum of total flow time and changeover cost. We provide properties of optimal solutions and develop an explicit characterization of optimal sequences, while showing that this characterization has recurrent properties. Our structural results have interesting implications for practitioners, primarily that the structure of optimal sequences is robust to changes in demand.     

Method ruggedness studies incorporating a risk based approach: a tutorial

This tutorial explains how well thought-out application of design and analysis methodology, combined with risk assessment, leads to improved assessment of method ruggedness. The authors define analytical method ruggedness as an experimental evaluation of noise factors such as analyst, instrument or stationary phase batch. Ruggedness testing is usually performed upon transfer of a method to another laboratory, however, it can also be employed during method development when an assessment of the method's inherent variability is required. The use of a ruggedness study provides a more rigorous method for assessing method precision than a simple comparative intermediate precision study which is typically performed as part of method validation. Prior to designing a ruggedness study, factors that are likely to have a significant effect on the performance of the method should be identified (via a risk assessment) and controlled where appropriate. Noise factors that are not controlled are considered for inclusion in the study. The purpose of the study should be to challenge the method and identify whether any noise factors significantly affect the method's precision. The results from the study are firstly used to identify any special cause variability due to specific attributable circumstances. Secondly, common cause variability is apportioned to determine which factors are responsible for most of the variability. The total common cause variability can then be used to assess whether the method's precision requirements are achievable. The approach used to design and analyse method ruggedness studies will be covered in this tutorial using a real example.     

Hydrothermal Synthesis,Crystal Structure,and Luminescent Properties of Two Zinc(II) and Cadmium(II) 3D Metal‐­Organic Frameworks

Two zinc(II) and cadmium(II) metal‐organic frameworks with mixed ligands, {[Zn₂(biim‐4)₂(TDC)₂] · 2.5H₂O}_n ( 1 ) and {[Cd₂(biim‐4)₂(TDC)₂ · 2H₂O]}_n ( 2 ) [biim‐4 = 1,1′‐(1,4‐butanediyl)bis(imidazole); H₂TDC = thiophene‐2,5‐dicarboxylic acid], were hydrothermally synthesized. Both of them are characterized by elemental analysis, IR spectroscopy, and single crystal X‐ray diffraction. In 1 , the four‐connected Zn^II nodes are connected by four linear ligands extending into a 3D network, which further integrates a fivefold interpenetrating diamond 3D topological network and the free water molecules distribute in void space, whereas in 2 , the Cd^II ions are in a distorted octahedral arrangement linked by TDC^2– and biim‐4 ligands to construct a 3D framework. In topology analysis, C11 and C14 are simplified as 3‐connected nodes and the 3D framework displays a (3,5)‐connected net. Furthermore, the thermal and photoluminescent properties of 1 and 2 were also studied.     

激光诱导击穿光谱技术对火车车轮钢中成分的原位统计分布分析表征

随着铁路规模的迅速扩大,对列车运行的可靠性及耐久性的要求也越来越高,车轮作为铁路机车车辆行走系统的核心部件,它与轨道之间的摩擦既要保证安全又要提升速度,车轮材料的性能直接影响车轮对磨损和滚动接触疲劳损伤的敏感性,其服役性能也受到高度关注。研究表明,车轮钢材料的成分及分布状态可对其组织性能产生显著影响,因此,运用激光诱导击穿光谱分析技术结合原位统计分布分析方法,通过其可多元素同步快速分析的高效性、较好的空间分辨能力、较大区域内的扫描分析能力等技术优势,结合统计分布分析方法,实现对车轮钢材料成分及其分布状态的快速表征。选取垂直于车轮轮辋外侧面作为分析面,对其进行低倍检测观察到在远离踏面的区域存在明显的粗大树枝晶结构,其组织结构存在不均匀性,并以此作为特征分析区域进行取样,采用320目的氧化铝砂纸进行表面处理,利用LIBSOPA系统进行成分分布分析。首先,在不同剥蚀条件下对各元素特征谱线的光谱信号强度及其稳定性进行比对分析,优化选定了20个预剥蚀10个剥蚀作为实验条件;其次,采用内标法建立了火车车轮钢中Si,Mn,P,S,Cr,Ni,Mo,Cu和V等九个元素的定量分析方法并对车轮钢样品中的元素含量进行测定,其定量结果与直读光谱分析的结果具有较好的一致性;最后对样品进行了区域扫描并运用统计偏析度对各元素的成分分布状态进行了统计表征,成分分布分区统计结果显示所有元素靠近踏面区域的统计偏析度均小于远离踏面区的统计偏析度,结合成分二维分布图可知,测试样品远离踏面区域的成分分布不均匀,其结果与低倍检验方法观察到的结果对应性较好。运用LIBSOPA 技术实现了对火车车轮钢材料中多元素的成分分布表征,为快速判定车轮钢材料成分及分布状态提供了全新的思路和表征手段。     

Blind separation to improve classification of traffic noise

In order to apply noise mapping to traffic noise prediction, a knowledge of several information about traffic characteristics is required to predict the noise levels emitted by the roads involved. In the European case, the CNOSSOS-EU calculation method for traffic-noise level prediction is now under discussion, to be agreed in response to the European Directive relating to the Assessment and Management of Environmental Noise (2002/49/EC). In this application context, standard ISO 1996-2:2007 Determination of Environmental Noise Levels, in its Section 6.2, specifically mentions that during L_eq measurements of road traffic noise the number of vehicle pass-bys shall be counted during the measurement time interval. This information is often not available in many roads, so it is typically registered by means of casual counts, often through manual procedures. Besides, if the measurement result is converted to other traffic conditions, a categorization of the vehicles involved is also required. Some additional information, such as the traffic density and the average speed, should be registered if a calculation method is used to build a noise map.In this paper a new automatic classification system of traffic noise covering these requirements is presented. The portable system processes a two channel audio recording to provide information of the average speed and the number of vehicles, which are classified in six categories during the measurement period. After several evaluations of the possibilities to get a good classification of the noise emission of a road from audio recordings, it is shown that increasing the within-class separation, as well as introducing a novel BSS–PCA-based classifier, the precision achieved in the final results is substantially improved.     

Analytical model, analysis and parameter optimization of a super linear electro-optic modulator (SFDR > 130 dB)

An analytical model of a super linear optical modulator with high spurious-free-dynamic-range (SFDR > 130 dB) is presented and analyzed. The linear modulator is referred to as IMPACC which stands for Interferometric Modulator with Phase-modulating And Cavity-modulating Components. The modulator is based on a unique combination of a RF-driven phase-modulator (PM) and a ring resonator (RR) within a Mach-Zehnder interferometer (MZI) configuration. Our analysis shows that our design can achieve SFDR values which are ~ 20 dB higher than the standard MZI modulator and 3-5 dB from the Ring Assisted Mach-Zehnder Interferometer (RAMZI) modulator. Both PM and RR in the IMPACC are simultaneously driven by a RF signal of the same frequency, but not necessarily the same amplitudes. The analytical model shows that the combination of these two optical elements, with the proper choice of RF-driving and device parameters, can lead to four important and compelling consequences. First, it offers a wholistic and elegant model in which the standard MZI modulator and the RAMZI modulator are just special cases of IMPACC. Second, the model offers an excellent parameter optimization methodology for fast parameter (internal and/or external) selection and performance evaluation. Third, it provides additional degree of control through the introduction of an external control parameter, the RF power split ratio (F). Lastly, it demonstrates one unique feature of IMPACC such as adaptive SFDR characteristics, where manufacturing tolerances in the transmission coefficient (τ) of the RR can be compensated with proper adjustments of the external parameter of the power split ratio (F).     

Ricci-positive metrics on connected sums of projective spaces

It is a well known result of Gromov that all manifolds of a given dimension with positive sectional curvature are subject to a universal bound on the sum of their Betti numbers. On the other hand, there is no such bound for manifolds with positive Ricci curvature: indeed, Perelman constructed Ricci positive metrics on arbitrary connected sums of complex projective planes. In this paper, we revisit and extend Perelman's techniques to construct Ricci positive metrics on arbitrary connected sums of complex, quaternionic, and octonionic projective spaces in every dimension.     

On the Numerical Range of Rational Matrix Functions

In this paper we investigate bounds of the numerical range of the derivative of a rational matrix function. Moreover, some results on connectedness are presented.