Propane oxidation over Pd/LaFe0.8Co0.2O3 catalyst

Pd/LaFe_0.8Co_0.2O₃ was found to be more active than the Pd/Al₂O₃ catalyst in propane oxidation. Activity and the oxidation state of palladium were strongly affected by the redox ratio (S) of reactants. Higher propane conversion could be obtained under rich conditions at higher temperatures, contributing to steam reforming. The presence of excess steam would bring about inhibition and oscillation.     

分数导数结合傅里叶最小二乘拟合处理含噪音的重迭信号

提出了一种含噪音重迭信号的综合处理方法 :先用傅里叶最小二乘法拟合噪音数据 ,然后对拟合后的信号求 2 .5次导数 ,在对模拟数据研究的基础上 ,讨论了求导后峰位漂移及其影响因素 ,给出了一个用于矫正峰位值的经验公式。用该方法对模拟和实际的紫外含噪音重迭信号进行处理 ,结果良好     

Maximum spectrum of continuous wavelet transform and its application in resolving an overlapped signal

To estimate the number of peaks and to find the individual peak positions in an overlapped signal, a new method called maximum spectrum of continuous wavelet transform (MSCWT) was developed by extracting the maximum coefficients of continuous wavelet transform (CWT). The peak position in MSCWT was the same as that in its original signal. In this process, CWT was performed not on a single dilation but on an appreciation dilation range. To obtain such a range, a new criterion was introduced to choose a center dilation, which was used to form the dilation range. If Cdilation denoted the center dilation, the proper dilation range was [Cdilation -6 +/- 2, Cdilation +1 +/- 1]. The Mexican Hat function was an analytical wavelet. Utilizing the information of the peak number and the position detected by MSCWT, a fitting route was performed to recover the original signal. One simulated and four true overlapped signals, including high performance liquid chromatography (HPLC), ultraviolet-visible (UV) spectrum, and differential pulse voltammetric (DPV), were processed, and the results indicated that MSCWT could detect an overlapped peak number and position, and the curve fitting based on information of MSCWT had a higher accuracy. The proposed method was an efficient one in resolving different types of overlapped signals.     

Hippocampal metabolomics using ultrahigh-resolution mass spectrometry reveals neuroinflammation from Alzheimer’s disease in CRND8 mice

In the wake of genomics, metabolomics characterizes the small molecular metabolites revealing the phenotypes induced by gene mutants. To address the metabolic signatures in the hippocampus of the amyloid-beta (Aβ) peptides produced in transgenic (Tg) CRND8 mice, high-field ion cyclotron resonance–Fourier transform mass spectrometry supported by LC-LTQ-Orbitrap was introduced to profile the extracted metabolites. More than 10,000 ions were detected in the mass profile for each sample. Subsequently, peak alignment and the 80 % rule followed by feature selection based on T score computation were performed. The putative identification was also conducted using the highly accurate masses with isotopic distribution by interfacing the MassTRIX database as well as MS/MS fragmentation generated in the LTQ-Orbitrap after chromatographic separation. Consequently, 58 differentiating masses were tentatively identified while up to 44 differentiating elemental compositions could not be biologically annotated in the databases. Nonetheless, of the putatively annotated masses, eicosanoids in arachidonic acid metabolism, fatty acid beta-oxidation disorders as well as disturbed glucose metabolism were highlighted as metabolic traits of Aβ toxicity in Tg CRND8 mice. Furthermore, a web-based bioinformatic tool was used for simulation of the metabolic pathways. As a result of the obtained metabolic signatures, the arachidonic acid metabolism dominates the metabolic perturbation in hippocampal tissues of Tg CRND8 mice compared to non-Tg littermates, indicating that Aβ toxicity functions neuroinflammation in hippocampal tissue and new theranostic opportunities might be offered by characterization of altered arachidonic acid metabolism for Alzheimer’s disease.      

Distributed finite-time coordinated tracking control for multiple Euler–Lagrange systems with input nonlinearity

Nonlinear Dynamics - In this paper, distributed finite-time coordinated tracking control for multiple Euler–Lagrange systems with input nonlinearity is investigated by using backstepping...     

Investigations in the recrystallization of evolved gases from pyrolysis process of melamine

Journal of Thermal Analysis and Calorimetry - A complete analysis of the thermal process about melamine was presented, in which different methods were applied to determine the characteristic of the...     

国产二十万千瓦汽轮机高中压缸准三维气动热力分析

本文采用准三维计算方法分析了国产二十万千瓦汽轮机在运行工况条件下的高中压缸气动热力性能.S1计算分析了叶型表面等摘马赫数分市情况及叶型的性能，S2计算得到了沿叶片高度的气动热力参数分布并分析了主要的通流性能参数，最后为改造设计提出了若干建议．     

两种透平叶栅三维流动的计算分析

本文以数值手段分析研究两种不同叶片造型的三维环形叶棚内的定常粘性流动及损失情况，数值方法采用三维可压缩粘性流动压力校正其法求解N－S方程及k－ε双方程湍流模型．新一代透平叶片型线设计与传统叶片型线的差别在于叶片型线的后部加载特性．本文通过计算分析了这种后加载叶片与传统加教叶片应用于汽轮机时对控制三级叶栅损失与二次流发展的作用．     

Origin of the generally defined absorption edge of non-stoichiometric lithium niobate crystals

The ultraviolet absorption edges of LiNbO₃ crystals with different Li₂O contents and MgO doping concentrations were investigated. The generally defined absorption edges at absorption coefficient α=15 or 20 cm⁻¹ of all these crystals fit the Urbach rule perfectly. The origin of this absorption edges in non-stoichiometric LiNbO₃ crystals is attributed to the presence of Li vacancies.     

叶栅边界层转捩的实验研究与一个新的综合经验准则

叶栅边界层转捩的实验研究与一个新的综合经验准则蒋洪德，仲永兴，凌君（中国科学院工程热物理研究所北京１０００８０）（中国航空工业总公司６２４所）关键词转捩实验，经验准则１前言现代航空发动机的风扇、压气机和涡轮叶栅在工作状态下弦长雷诺数一般在１０５～１０...