Substituent engineering in g-C3N4/COF heterojunctions for rapid charge separation and high photo-redox activity

Science China Chemistry - The heterojunction constructed of covalent organic frameworks (COFs) with adjustable structure and other photocatalysts has great potential in the field of photocatalysis....     

基于粒子滤波的运动目标光电定位仿真研究

运动目标的光电定位不能像静止目标那样简单做均值滤波，鉴于此，引入粒子滤波算法，它不仅可以应用于线性系统，而且还适用于非线性系统。结合光电定位需求，详细推导了计算公式及初值和参数选取公式，对只含测量噪声以及含有测量和运动噪声等的海面运动目标光电无源定位算法进行了仿真计算，验证了算法的有效性，讨论了噪声强度对滤波效果的影响，滤波参数选择对滤波效果的影响，目标运动方式对滤波跟随性的影响，重采样算法对滤波效果的影响等。所得结论为:粒子滤波可用于运动目标光电定位过程，可有效降低定位误差；粒子滤波算法具有较强鲁棒性，适用于噪声较大、目标运动形态变化大等情况。     

Development,validation and application of a UHPLC–MS/MS method for quantification of the adiponectin-derived active peptide ADP355 in rat plasma

A UHPLC–MS/MS method for the quantification of ADP355, an adiponectin-derived active peptide, was developed and validated. The extraction method employed simple protein precipitation using methanol and chromatographic separation was achieved on anAccucore™ RP-MS C₁₈ column (100 × 2.1 mm, 2.6 μm, 80 Å), using 0.1% formic acid in both water and acetonitrile with gradient elution at the flow rate of 400 μl/min within 4.0 min. Detections were performed under positive ion mode with multiple reaction monitoring ion transitions m/z 1109.2 → 309.8 and 871.4 → 310.1 for ADP355 and Jt003 respectively at unit resolution. The linearity range of the calibration curve was 2–1,000 ng/ml with a lower limit detection of 0.5 ng/ml. The selectivity, linearity, precision, accuracy, recovery, matrix effect and stability were validated, and all items met the requirement of US Food and Drug Administration guidance. This method was successfully applied to an intravenous pharmacokinetic study of ADP355 in rats and the in-vitro stability in rat serum, plasma and whole blood was also assessed.     

Breaking Surface Atomic Monogeneity of Rh2P Nanocatalysts by Defect-Derived Phosphorus Vacancies for Efficient Alkaline Hydrogen Oxidation

Breaking atomic monogeneity of catalyst surfaces is promising for constructing synergistic active centers to cope with complex multi-step catalytic reactions. Here, we report a defect-derived strategy for creating surface phosphorous vacancies (P-vacancies) on nanometric Rh₂P electrocatalysts toward drastically boosted electrocatalysis for alkaline hydrogen oxidation reaction (HOR). This strategy disrupts the monogeneity and atomic regularity of the thermodynamically stable P-terminated surfaces. Density functional theory calculations initially verify that the competitive adsorption behavior of H_ad and OH_ad on perfect P-terminated Rh₂P{200} facets (p-Rh₂P) can be bypassed on defective Rh₂P{200} surfaces (d-Rh₂P). The P-vacancies enable the exposure of sub-surface Rh atoms to act as exclusive H adsorption sites. Therein, the H_ad cooperates with the OH_ad on the peripheral P-sites to effectively accelerate the alkaline HOR. Defective Rh₂P nanowires (d-Rh₂P NWs) and perfect Rh₂P nanocubes (p-Rh₂P NCs) are then elaborately synthesized to experimentally represent the d-Rh₂P and p-Rh₂P catalytic surfaces. As expected, the P-vacancy-enriched d-Rh₂P NWs catalyst exhibits extremely high catalytic activity and outstanding CO tolerance for alkaline HOR electrocatalysis, attaining 5.7 and 14.3 times mass activity that of p-Rh₂P NCs and commercial Pt/C, respectively. This work sheds light on breaking the surface atomic monogeneity for the development of efficient heterogeneous catalysts.     

Cu催化吲哚啉的炔丙基烷基化/脱氢对映选择性合成手性N-炔丙基吲哚化合物(英文)

基于吲哚啉的Cu催化不对称炔丙基烷基化及DDQ脱氢策略,成功合成了手性N-炔丙基吲哚化合物.通过使用一个结构刚性的酮亚胺三齿P,N,N-配体,反应获得了很好的对映选择性.该方法反应条件温和、底物适用范围广、产物收率高、立体选择性好,为手性N-炔丙基吲哚化合物的合成提供了一条简捷、高效的新途径.     

半平面多边缘裂纹反平面问题的奇异积分方程

利用复变函数和奇异积分方程方法,求解弹性范围内半平面多边缘裂纹的反平面问题．提出了满足半平面边界自由的由分布位错密度表示的单边缘裂纹的基本解,此基本解由主要部分和辅助部分组成．将半平面多边缘裂纹问题看作是许多单边缘裂纹问题的叠加,建立了一组Cauchy型奇异积分方程．然后,利用半开型积分法则求解该奇异积分方程,得到了裂纹端处的应力强度因子．最后,给出了几个数值算例．     

干摩擦条件下聚甲醛塑料动力齿轮传动啮合效率的分析研究与计算

从高分子材料的粘弹性力学模型出发，推导出塑料与钢齿轮副粘滞发热损耗功率的计算公式，并以此为基础，结合塑料材料的弹性模量和滑动摩擦系数的测试数据，考虑温度、弹性模量、摩擦系数及载荷之间复杂的偶合关系，研究并提出了一种在干摩擦条件下塑料与钢齿轮副啮合效率的数值计算方法，运用这种方法，可以方便地获得任意啮合位置的瞬时啮合效率及一个啮合循环中的平均啮合效率，通过对聚甲醛与４５＾＃钢齿轮副的计算发现，在干摩     

分析薄壳塑性动力响应问题的一种数值方法

探索薄壳塑性动力响应问题的分析与数值方法,是当今力学中的重要课题之一。笔者曾给出联合应用拉普拉斯变换和最小二乘法分析梁、板、壳塑性动力响应的方法。本文分别针对承受中载的短壳和长壳问题,给出只用最小二乘法分析其塑性动力响应的方法。     

A continuum model for intermittent deformation of single crystal micropillars

Strain bursts are often observed during compression tests of single crystal micropillars. In this work, we formulate a new continuum model that accounts for the strain bursts within the framework of crystal plasticity. The strain bursts are separated from the loading stage (nearly elastic loading) by introducing a dimensionless constant in the continuum model, and are detected by load serrations. The boundary conditions in the context of micropillar compression are studied and they are shown to be changing and unpredictable as plastic deformation proceeds. To evaluate the validity of our model, finite element simulations of the uniaxial compression tests on nickel micropillars are performed. Our simulations produce clearly visible strain bursts during the plastic flow and the produced intermittent flows are comparable with the experimental observations. For the bulk crystal, a series of strain bursts is identified in the course of plastic flow, despite an apparently smooth stress–strain response. We also show that the intermittent flow is intensified in the micrometer-scale due to both increasing numbers of the successive strain bursts and increasing amplitude of the strain burst, when the specimen size decreases. Finally, we show that the occurrences of the strain bursts are always associated with negative values of the second-order work.     

Synthesis of 12‐aryl‐12H‐benzo[i][1,3]‐dioxolo[4,5‐b]xanthene‐6,11‐diones using silica sulfuric acid as an efficient and versatile catalyst under solvent‐free conditions

Some novel 12‐aryl‐12H‐benzo[i][1,3]‐dioxolo[4,5‐b]xanthene‐6,11‐diones can be rapidly and efficiently synthesized in excellent yields by condensing a variety of aldehydes with 3,4‐methylenedioxyphenol and 2‐hydroxy‐1,4‐naphthoquinone in the presence of a catalytic amount of silica sulfuric acid under solvent‐free conditions. The simple experimental procedure, solvent‐free reaction conditions, utilization of an inexpensive and readily available catalyst, short period of conversion, and excellent yields are the advantages of the present method. Furthermore, the catalyst can be recycled and reused three times without significant loss of activity. The structures of the novel compounds are confirmed by IR, ¹H‐NMR, ¹³C‐NMR, MS, and elemental analysis. J. Heterocyclic Chem., 2011.