金橙G螯合形成树脂分离富集地质样品中的微量贵金属

主要研究了金橙Ｇ螯合形成树脂分离富集地质样品中金、铂、钯的最佳实验条件。在柱高大于１６ｃｍ，０．１ｍｏｌ／Ｌ ＨＣｌ介质的样品溶液以小于或等于０．５ｍＬ／ｍｉｎ流速过柱，用０．１ｍｏｌ／Ｌ ＨＣｌ的３％硫脲溶液以小于或等于０．５ｍＬ／ｍｉｎ流速洗脱金、铂、钯（和铑），都能同时定量富集。用火焰原子吸收光谱法测定，回收率均在９５％￣１１０％之间。经地质样品加标准回收实验，结果令人满意。证明这种以磺酸基     

Modification of hydrophilic channels in Nafion membranes by DMBA: Mechanism and effects on proton conductivity

Modification of proton conductive channels (PCCs) in Nafion has been achieved with the assistance of 3, 4‐dimethylbenzaldehyde (DMBA). During annealing, ionic clusters develop from small isolated spheres (1.72 nm) to wide continuous channels (5.15 nm), and the crystallinity of Nafion/DMBA membranes is also improved from 17% to 32% as shown by X‐ray diffraction. Molecular dynamic simulation reveals that hydrogen bonding and hydrophobic interaction between DMBA and Nafion work synergistically to achieve better phase separation. The morphology–property relationship shows that, versus various PCCs width, the corresponding proton conductivities vary greatly from 0.079 to 0.139 S/cm at 80 °C. By carefully tuning the width of PCCs, the proton conductivity shows an improvement of 22–34% as compared with pristine Nafion. A significant enhancement on the maximum power density is achieved for the membrane electrode assembly on Nafion/DMBA‐8h (as high as 1018 mW/cm^?2), yielding an enhancement of 39% on pristine Nafion‐8h (730 mW/cm^?2). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 52, 1107–1117     

On the Variability of Heart Rate Variability—Evidence from Prospective Study of Healthy Young College Students

Heart rate variability (HRV) has been widely used as indices for autonomic regulation, including linear analyses, entropy and multi-scale entropy based nonlinear analyses, and however, it is strongly influenced by the conditions under which the signal is being recorded. To investigate the variability of healthy HRV under different settings, we recorded electrocardiograph (ECG) signals from 56 healthy young college students (20 h for each participant) at campus using wearable single-lead ECG device. Accurate R peak to R peak (RR) intervals were extracted by combing the advantages of five commonly used R-peak detection algorithms to eliminate data quality influence. Thorough and detailed linear and nonlinear HRV analyses were performed. Variability of HRV metrics were evaluated from five categories: (1) different states of daily activities; (2) different recording time period in the same day during free-running daily activities; (3) body postures of sitting and lying; (4) lying on the left, right and back; and (5) gender influence. For most of the analyzed HRV metrics, significant differences (p < 0.05) were found among different recording conditions within the five categories except lying on different positions. Results suggested that the standardization of ECG data collection and HRV analysis should be implemented in HRV related studies, especially for entropy and multi-scale entropy based analyses. Furthermore, this preliminary study provides reference values of HRV indices under various recording conditions of healthy young subjects that could be useful information for different applications (e.g., health monitoring and management).     

气相中HRnCCH和X(X=H_2O,NH_3)反应机理的理论研究

在CCSD(T)//MP2/aug-cc-pVTZ-pp理论水平上,研究了HRnCCH与大气中H2O及NH3分子反应的机理,反应主要包括HRnCCH与HRnOH及HRnNH2之间的转化、H2O和NH3在HRnCCH中的碳碳三键上的加成反应以及HRnCCH与双分子水反应等.结果表明,HRnCCH与H2O反应生成HCCH和HRnOH及HRnCCH与NH3反应生成HCCH和HRnNH2的能垒分别为54.1和75.2 kJ/mol,而生成HRnCHC(OH)H,HRnC(OH)CH2,HRnCHC(NH2)H和HRnC(NH2)CH2的活化能分别为219.6,220.5,174.4和182.4kJ/mol,此结果表明HRnCCH反应性较弱且是稳态存在的.此外,在HRnCCH与H2O反应中加入单个水分子,仍然生成HRnCHC(OH)H,但反应活化能却降低了96.4 kJ/mol,说明水分子对该反应有明显的催化作用.     

Global exponential stability in Lagrange sense for recurrent neural networks with both time-varying delays and general activation functions via LMI approach

In this paper, we study the global exponential stability in a Lagrange sense for recurrent neural networks with both time-varying delays and general activation functions. Based on assuming that the activation functions are neither bounded nor monotonous or differentiable, several algebraic criterions in linear matrix inequality form for the global exponential stability in a Lagrange sense of the neural networks are obtained by virtue of Lyapunov functions and Halanay delay differential inequality. Meanwhile, the estimations of the globally exponentially attractive sets are given out. The results derived here are more general than that of the existing reference. Finally, two examples are given and analyzed to demonstrate our results.     

Simulated annealing for financing cost distribution based project payment scheduling from a joint perspective

Based on the distribution of the project financing cost over the contractor and the client, this paper involves the project payment scheduling problem from a joint perspective of the two parties. In the problem, the project financing cost is defined as the expense for raising money from the outside or the opportunity cost of the capital devoted into the project and the objective is to find the project payment schedule that can not only maximize the joint revenue of the two parties but also be accepted by them. Based on the characteristics of the problem, an optimization model consisting of two submodels is constructed using the activity-based method. For the strong NP-hardness of the problem, two simulated annealing algorithms with different searching structures are developed and compared with the multi-start iterative improvement method on the basis of a computational experiment performed on a data set generated randomly. The results show that the simulated annealing algorithm with the nested loop module seems to be the most promising algorithm for solving the defined problem especially when the scale of the problem becomes larger. In addition, the influences of some key parameters on the computational results are investigated through the full factorial experiment and a few useful conclusions are drawn.     

A Mixed Ionic and Electronic Conducting Dual‐Phase Membrane with High Oxygen Permeability

To combine good chemical stability and high oxygen permeability, a mixed ionic‐electronic conducting (MIEC) 75 wt % Ce_0.85Gd_0.1Cu_0.05O_2?δ‐25 wt % La_0.6Ca_0.4FeO_3?δ (CGCO‐LCF) dual‐phase membrane based on a MIEC–MIEC composite has been developed. Copper doping into Ce_0.9Gd_0.1O_2?δ (CGO) oxide enhances both ionic and electronic conductivity, which then leads to a change from ionic conduction to mixed conduction at elevated temperatures. For the first time we demonstrate that an intergranular film with 2–10 nm thickness containing Ce, Ca, Gd, La, and Fe has been formed between the CGCO grains in the CGCO‐LCF one‐pot dual‐phase membrane. A high oxygen permeation flux of 0.70 mL min^?1 cm^?2 is obtained by the CGCO‐LCF one‐pot dual‐phase membrane with 0.5 mm thickness at 950 °C using pure CO₂ as the sweep gas, and the membrane shows excellent stability in the presence of CO₂ even at lower temperatures (800 °C) during long‐term operation.     

红外单站多目标跟踪算法研究

利用IRST(红外搜索与跟踪)系统所获取的各目标的角度及其红外光谱辐射功率和信息，通过对红外光谱辅射功率和的相关处理，运用选优的JPDA（联合概率数据关联）算法与IMM（交互多模型）算法实现了IRST系统的单站多目标跟踪，并通过两个仿真场景对算法性能进行了检验.仿真结果表明：在跟踪开始阶段，两个场景中的每个目标都能获得高精度的跟踪;当目标编队飞行时，算法能对各目标进行有效的跟踪，而且跟踪精确度也是令人满意的;当目标交叉飞行时，跟踪的误差明显加大，随着时间的延续，对远距离目标会失去跟踪能力，但对近距离目标仍能进行有效的跟踪.