Solvent effect of ionic liquids on the distribution constant of 2-thenoyltrifluoroacetone and its nickel(II) and copper(II) chelates and the evaluation of the solvent properties based on the regular solution theory

Distribution constants of 2-thenoyltrifluoroacetone (Htta) and its Ni(II)and Cu(II) chelates between 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (C_nmimTf₂N; n = 4, 6, and 8) as ionic liquid (IL) and an aqueous phase were determined. The enol fraction of Htta in ILs was spectrophotometrically measured to calculate the distribution constant of the enol form (K_D,HE) of Htta. The K_D,HE values in ILs were evaluated by comparing those in various molecular solvents such as alkanes, aromatic hydrocarbons, chlorohydrocarbons, ethers, ketones, and esters previously reported on the basis of the regular solution theory (RST). It was elucidated that the IL solutions of Htta (enol) can be taken as apparently regular solutions as expected in the organic solvents. On the other hand, the effect of ILs on the distribution constant of metal(II) chelates (K_D,M) was fairly complicated. The Cu(tta)₂-IL solutions behaved like the alkane and aromatic hydrocarbon solutions but the Ni(tta)₂-IL (C₄mimTf₂N) like ether and ketone solutions. In the Ni(II) case, some specific interactions between the Ni(II) chelate and IL was suggested. Finally, the solubility parameters of ILs were calculated using K_D,HE by RST and were in good agreement with the literature values obtained by the enthalpy of vaporization.     

磷含量对NiMo/γ-Al_2O_3催化剂活性相结构的影响

采用程序升温还原(TPR)、高分辨透射电镜(HRTEM)和X射线光电子能谱(XPS)表征手段对共浸渍法制备的不同磷含量NiMo/γ-Al2O3催化剂进行了表征,研究了磷含量对NiMo/γ-Al2O3催化剂活性相结构的影响。TPR研究表明,磷能够减少四面体配位Mo物种的数量,增加八面体配位Mo物种的数量,促进高活性Ⅱ型"Ni-Mo-S"活性相的形成。HRTEM研究表明,随磷含量的增加,MoS2颗粒堆积层数增加,催化剂的加氢选择性提高;适量磷能够增加边角位有效Mo原子的分散度(fMo),增加催化剂表面加氢脱硫(HDS)和加氢脱氮(HDN)活性位的数量。上述结论得到了XPS表征的证实:适量磷增加了催化剂表面Mo原子浓度、提高有效助剂比率(PR)和提升比率(Ni/Mo),相应催化剂表现出最高的HDS和HDN活性;但过高磷含量能够引起MoS2颗粒过度堆积,片层长度过长,导致活性位数量减少,催化活性降低。     

Thermal desorption/gas chromatography/mass spectrometry approach for characterization of the volatile fraction from amber specimens: A possibility of tracking geological origins

Research on the chemical composition of fossil resins has evolved during the last decades as a multidisciplinary field and is strongly oriented toward the correlation with their geological and botanical origin. Various extraction procedures and chromatographic techniques have been used together for identifying the volatile compounds contained in the fossil resin matrix. Hyphenation between thermal desorption (TD), gas chromatography (GC) and mass spectrometry detection (MS) has been chosen to investigate the volatile compounds fraction from ambers with a focus on Romanite (Romanian amber) and Baltic amber species. A data analysis procedure was developed for the main purpose of fingerprinting ambers based on the MS identity of the peaks generated by the volatile fraction, together with their relative percentual area within the chromatogram. Chromatographic data analysis was based entirely on Automated Mass Spectral Deconvolution & Identification System (AMDIS) software to produce deconvoluted mass spectra which were used to build-up a mixed mass spectra and relative retention scale library. Multivariate data analysis was further applied on AMDIS results with successful discrimination between Romanite and Baltic ambers. A special trial was conducted to generate pyrolysis “like” macromolecular structure breakdown to volatile compounds by gamma irradiation with a high absorbed dose of 500 kGy. Contrary to our expectations the volatile fraction fingerprints were not modified after irradiation experiments. A complementary non-destructive new approach by ESR spectroscopy was also proposed for discriminating between Romanite and Baltic ambers.     

高体分SiC_p/Al复合材料螺纹性能的测试

从SiCp/Al复合材料性能分析着手,讨论了预置件法、焊接法和粘接法等在空间遥感器研制中常用的联接方法的优缺点,提出了在高体积分数(体分)SiCp/Al复合材料上直接加工螺纹,并加装钢丝螺套的方法来改善螺纹联接性能。对在某高体分SiCp/Al复合材料上加工的M4、M5螺纹进行了拉伸测试,结果表明:加装钢丝螺套前,复合材料螺纹有被拉脱现象;加装钢丝螺套后,M4螺纹、螺杆在3 000～4 000 N被拉断;M5螺纹、螺杆在8 000～9 000 N被拉断,测试后两种规格的螺纹状态良好,可以满足实际应用对该材料拉伸强度的要求,其已应用于工程项目中。     

大视场光学遥感器焦平面板的研制

焦平面板作为承载TDICCD器件的部件,其强度、动静态刚度、热稳定性直接影响到遥感器的成像质量.针对目前光学遥感器大视场、宽覆盖的发展趋势,设计了一种新型的焦平面板.选用性能指标优良的高体份SiC/Al复合材料,既满足了结构设计指标的要求,同时又大大降低了产品重量.通过有限元模拟仿真分析和相关试验,验证了设计方案的可行...     

高体分SiC_p/Al复合材料螺纹性能的测试

从SiCp/Al复合材料性能分析着手,讨论了预置件法、焊接法和粘接法等在空间遥感器研制中常用的联接方法的优缺点,提出了在高体积分数（体分）SiCp/Al复合材料上直接加工螺纹,并加装钢丝螺套的方法来改善螺纹联接性能。对在某高体分SiCp/Al复合材料上加工的M4、M5螺纹进行了拉伸测试,结果表明：加装钢丝螺套前,复合材料螺纹有被拉脱现象;加装钢丝螺套后,M4螺纹、螺杆在3 000～4 000 N被拉断;M5螺纹、螺杆在8 000～9 000 N被拉断,测试后两种规格的螺纹状态良好,可以满足实际应用对该材料拉伸强度的要求,其已应用于工程项目中。     

半透明介质相变中的辐射变物性问题

半透明介质相变传热在许多工程领域引起关注,其实质是变物性条件下伴随相变的辐射-导热瞬态耦合传热问题,其难点在于相变过程中的辐射变物性问题,尤其是折射率的时空演变问题.本文首次研究相变过程中的变折射率问题.假设相变介质存在固相-糊状-液相区,固/糊界面、液/糊界面假定为半透明漫反射.采用多层辐射传递模型模拟相变介质内的辐...     

A parallel radix‐4 block cyclic reduction algorithm

A conventional block cyclic reduction algorithm operates by halving the size of the linear system at each reduction step, that is, the algorithm is a radix‐2 method. An algorithm analogous to the block cyclic reduction known as the radix‐q partial solution variant of the cyclic reduction (PSCR) method allows the use of higher radix numbers and is thus more suitable for parallel architectures as it requires fever reduction steps. This paper presents an alternative and more intuitive way of deriving a radix‐4 block cyclic reduction method for systems with a coefficient matrix of the form tridiag{ ? I,D, ? I}. This is performed by modifying an existing radix‐2 block cyclic reduction method. The resulting algorithm is then parallelized by using the partial fraction technique. The parallel variant is demonstrated to be less computationally expensive when compared to the radix‐2 block cyclic reduction method in the sense that the total number of emerging subproblems is reduced. The method is also shown to be numerically stable and equivalent to the radix‐4 PSCR method. The numerical results archived correspond to the theoretical expectations. Copyright © 2013 John Wiley & Sons, Ltd.     

Spectral analysis for the Gauss problem on continued fractions

We present a new derivation of the formula appearing in Babenko (1978) and Mayer and Roepstorff (1987) that gives the probability distribution of τ⁻ⁿ${\tau }^{-n}$ in terms of the eigenvalues of a symmetric operator. Here τ$\tau$ is the well-known Gauss-map.     

特高含水期井震结合注采系统挖潜调整研究

进入特高含水期后,开展注采系统调整挖潜剩余油是油田持续稳产的关键.为了提高特高含水阶段油田采收率,提出井震结合方法精细标定构造层位、认识储层特征,构建地质模型并数值模拟剩余油分布,针对剩余油应用井震结合解释成果设计注采系统调整方案并优化相应注水强度.实验区块研究结果表明:特高含水期,采用井震结合注采系统调整方法最终产油量和采收率分别提高31.21×10~4t和1.54%,能够达到有效挖潜剩余油的目的;而改变注水强度对最终开发效果影响显著,随着注水强度增加,采收率先增大后减小,存在最佳的注水强度为9m~3/d·m.