Good polynomials for optimal LRC of low locality

Designs, Codes and Cryptography - According to a magnific method due to I. Tamo and A. Barg, a class of polynomials over finite fields, called good polynomials, was introduced and used to construct...     

Improving Data Quality in Traditional Low-Dose Scanning Transmission Electron Microscopy Imaging

It has become very important to study and find optimal conditions for imaging electron-beam (e-beam) sensitive materials in scanning transmission electron microscopy under low electron-dose with high signal-to-noise ratio (SNR). Convergence and collection angles and electron-probe current are essential parameters. However, these parameters have rarely been discussed in a systematic way. In this paper, the illumination and collection conditions are optimized according to the resolution requirement of different materials by adjusting the condenser and intermediate lenses in a commercial transmission electron microscope. To demonstrate the significance of optimizing these parameters, two examples, zeolite MFI and metal–organic framework (MOF) MIL-101, are taken among the sensitive materials, with the most important electron incidences along the [010] and <110> directions, respectively. High SNR atomic resolution images of MFI are obtained with e-beam current as low as 0.50 pA, reaching information transfer for reflection up to 18 0 2 corresponding to d-spacing of 0.11 nm, close to the resolution limit of 0.098 nm from resolvable diffraction limit. MOF MIL-101 is characterized under an even lower e-beam 0.2 pA to avoid severe beam damage. High-quality annular dark and bright field images are obtained, which proves the wide applicability of this method on more e-beam sensitive materials.     

军用飞机任务保障规划方案效率分析

针对军用飞机再次出动保障任务规划方案的效率分析缺乏有效的解决方法的问题,构建了基于灰色聚类算法与熵权法相结合的任务保障规划方案效率分析模型。该模型首先利用灰色聚类对保障方案的人员利用率的有效参数进行计算并确定。其后利用熵权法对保障方案的人员数量时间分布进行计算。在此基础上根据任务规划工期、人员利用率、人员数量时间分布三个参数的权重得到任务保障规划方案效率。文中通过实例对构建的效率分析模型进行了验证。结果表明：所构建的效率分析模型能够有效的对军用飞机任务保障规划方案效率分析,且具有较高的可靠性和很好的工程应用价值。     

鄱阳湖克氏原螯虾肌肉营养成分分析与评价

利用常规分析方法对鄱阳湖克氏原螯虾肌肉的营养成分进行测定,结果表明:肌肉中水分含量79.59%,粗蛋白含量18.70%,粗脂肪含量0.98%,粗灰分含量1.24%。钙含量443mg/100g干重,磷含量1 200.00mg/100g干重。氨基酸总量83.32%(色氨酸因酸解破坏),必需氨基酸含量28.25%,占氨基酸总量的33.91%,4种鲜味氨基酸的总含量为31.86%。必需脂肪酸含量14.38%,脂肪酸含量以C160和C181为最丰富,比例分别为21.50%和21.59%;EPA和DHA含量分别为9.17%和1.86%。脂肪酸中饱和脂肪酸(SFA)比例为33.59%,单不饱和脂肪酸(MUFA)比例为30.27%,多不饱和脂肪酸(PUFA)比例为25.58%。鄱阳湖克氏原螯虾是一种高蛋白低脂肪、营养丰富的淡水产品,值得大力推广养殖。     

膦酰基离子液体铕配合物的合成、结构与荧光性质

合成了两种膦酰基离子液体,1-丁基-3-(3-二苯基膦酰基)丙基咪唑六氟磷酸盐（[BIMC3P(O)Ph2]PF6）(IL-1)和(3-二苯基膦酰基)-丙基三乙胺六氟磷酸盐（[TEAC3P(O)Ph2]PF6）(IL-2),通过核磁共振和红外光谱确认了它们的结构,并合成了两种离子液体的稀土铕配合物Eu(IL-1)3(NO3)3和Eu(IL-2)3(NO3)3,对其进行了热稳定性和光谱性质的表征。 热重分析表明,离子液体的热稳定性均高于其稀土配合物,相比之下,离子液体IL-1和Eu(IL-1)3(NO3)3具有更好的热稳定性。 从红外光谱中可以看出,形成配合物后,两种离子液体中的P=O吸收峰均向低波数方向移动,同时两种配合物的紫外吸收强度均大于各自游离的离子液体,说明Eu3+和离子液体中的磷酰基发生了配位。 稀土铕配合物Eu(IL-1)3(NO3)3和Eu(IL-2)3(NO3)3的荧光光谱均表现出Eu3+的特征红光,峰形尖锐,单色性好,可作为潜在的红色发光材料。     

Highly branched and high‐molecular‐weight polyethylenes produced by 1‐[2,6‐bis(bis(4‐fluorophenyl)methyl)‐4‐MeOC6H2N]‐2‐aryliminoacenaphthylnickel(II) halides

A series of unsymmetrical 1‐[2,6‐bis(bis(4‐fluorophenyl)methyl)‐4‐MeOC₆H₂N]‐2‐aryliminoacenaphthene‐nickel(II) halides has been synthesized and fully characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (¹H NMR), ¹³C NMR, and ¹⁹F NMR spectroscopy as well as elemental analysis. The structures of Ni1 and Ni6 have been confirmed by the single‐crystal X‐ray diffraction. On activation with cocatalysts either ethylaluminum sesquichloride or methylaluminoxane, all the title nickel complexes display high activities toward ethylene polymerization up to 16.14 × 10⁶ g polyethylene (PE) mol^?1(Ni) h^?1 at 30 °C, affording PEs with both high branches (up to 103 branches/1000 carbons) and molecular weight (1.12 × 10⁶ g mol^?1) as well as narrow molecular weight distribution. High branching content of PE can be confirmed by high temperature ¹³C NMR spectroscopy and differential scanning calorimetry. In addition, the PE exhibited remarkable property of thermoplastic elastomers (TPEs) with high tensile strength (σ_b = 21.7 MPa) and elongation at break (ε_b = 937%) as well as elastic recovery (up to 85%), indicating a better alternative to commercial TPEs. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 130–145     

湿气源吸附碳捕集: CO2/H2O共吸附机制及应用

大型湿气源排放中普遍存在的水汽是制约吸附碳捕集规模化发展的重要挑战之一。H₂O的极性往往会导致吸附材料的CO₂捕集率降低甚至出现失效,也会造成捕集系统产生温降、压降等寄生损失,甚至形成设备腐蚀、吸附剂中毒等不利影响,最终额外能耗和成本大幅提高。为解决上述挑战,深入理解CO₂与H₂O共吸附过程的作用机制,据此开发成本合理、再生能耗低且对水气不敏感的高效CO₂吸附剂及吸附技术是实现湿气源下高效吸附碳捕集的重要途径。目前,由于分散在多个领域且各有侧重,关于H₂O对CO₂吸附影响的机制分析缺乏汇总与概括,难以形成相对统一的观点。本文针对CO₂与H₂O共吸附过程,从宏观与微观层面进行了详细综述。首先,基于共吸附机制的基础研究,依次介绍了竞争吸附、变湿吸附和呼吸效应领域的研究进展并进行了简要评价。其次,基于共吸附的应用研究,阐述了湿气源CO₂捕集技术的吸附剂研发与工艺改进两部分的现状及进展,也对不同湿气源下CO₂捕集水平进行了简要评价。最后,总结了目前研究中的不足之处并展望了未来的研究方向。本文将分散于各领域的CO₂与H₂O共吸附过程进行集中归纳、分析和对比,或可为湿气源碳捕集技术提供有效的指导。     

Preparation of ultrafine Cu1.5Mn1.5O4 spinel nanoparticles and its application in p-nitrophenol reduction

In this work, ultrafine Cu_1.5Mn_1.5O₄ spinel nanoparticles were successfully synthesized by a sol–gel method combined with two complexing agents, which was firstly employed in the reductive transformation from p-nitrophenol into p-aminophenol. The effect of calcination temperature on the crystal phase and microstructure of Cu_1.5Mn_1.5O₄ nanoparticles was investigated in this article. It was found that Cu_1.5Mn_1.5O₄ nanoparticles with pure spinel phase can be obtained at 500 °C with the help of EDTA acid–citric acid complexing agents. Below 500 °C, there exists some Mn₂O₃ impure phase. SEM characterization indicated that the particle size of the spinel Cu_1.5Mn_1.5O₄ rapidly increases above 600 °C. The catalytic experimental results show that the Cu_1.5Mn_1.5O₄ nanoparticles prepared at 500 °C exhibit the highest catalytic activity which is even superior to some precious metal catalysts. With the calcination temperature increasing, the catalytic activity of Cu_1.5Mn_1.5O₄ spinel nanoparticles gradually degrades which can be ascribed to the particle size growth of Cu_1.5Mn_1.5O₄. It can also be observed that all the oxide samples, namely CuO, Mn₂O₃ and Cu_1.5Mn_1.5O₄, possess certain catalytic ability for the transformation from p-nitrophenol into p-aminophenol. However, the catalytic activity of Cu_1.5Mn_1.5O₄ spinel nanoparticles is obviously higher than CuO and Mn₂O₃. Especially, Mn₂O₃ alone has very poor catalytic activity in the reduction of p-nitrophenol.

     

Correction to: Good polynomials for optimal LRC of low locality

Designs, Codes and Cryptography -