电磁内爆的一维显式数值模拟

 提出了一个用于电磁内爆过程数值模拟的一维磁流体力学显式模型，对中物院流体物理研究所1 MJ电容器组电磁内爆优化方案进行了计算，并将计算结果与一维德式模型的结果进行了比较。     

Stable single frequency and single polarization DFB fiber lasers operated at 1053 nm

Stable single-frequency and single-polarization distributed-feedback (DFB) fiber laser was realized by giving a pressure on the phase shift region of the fiber grating. The output wavelength of the DFB fiber laser is 1053 nm. When the pump power of 980 nm laser diode is 100 and 254 mW, the output power can reach 8.3 and 37.1 mW and the polarization extinction ratio was 26 and 20 dB, respectively. After chopped by Acousto-optic modulator (0.3 Hz), the pulse peak value variance is 4.65%(peak to peak) and 1.098% (RMS) for 31 min.     

YAG:Ce蓝光转换材料的合成和发光性质研究

铈激活的钇铝石榴石(YAG:Ce)由高温固相反应制备.样品证明为纯的的石榴石物相.YAG:Ce的激发光谱为双峰结构,主要激发峰在460nm,与GaN的蓝光发射匹配.YAG:Ce的发射光谱为一宽带,波长范围从蓝绿到红,主峰波长为540nm,能与GaN的蓝光组合形成高亮度白光.YAG:Ce在漫反射光谱中的的两个吸收峰与YAG:Ce的激发峰相吻合,进一步证明了铈激活的YAG对GaN蓝光的有效吸收.YAG:Ce有很高的发光强度和高达89%的量子效率.     

Nanotribological properties of silicon surfaces nanopatterned by laser interference lithography

The problems caused by the adhesive force and friction force become more critical when the size of M/NEMS devices shrinks to micro/nano-scale. The nanotexture-patterned surface is an effective approach to reduce friction force on micro/nano-scale. Laser interference lithography is an attractive method to fabricate micro/nanotextures, which is maskless and allows large area periodical structures to be patterned by a couple of seconds’ exposure in a simple equipment system. We fabricate various nanogrooves with different pitch and space width on silicon wafers by laser interference lithography and chemical etching. We investigate the nanotribological properties of the patterned surfaces by AFM/FFM. We show that friction on the nano/micro-scale is related to the coverage rate of the nanogrooves, which decreases with increase in the space width and decrease in the pitch.     

Stability of pyrimidine N-glycosydic bonds in the presence of Lawesson’s reagents: revisit of 2-thiolation of pyrimidine nucleosides

2-Thiolation of O4-phenylthymidine and 4-thiothymidine using Lawesson’s reagents proceeded differently. The glycosydic bond of O4-phenylthymidine quickly dissociated when treated with Lawesson’s reagent, whereas 4-thiothymidine was reasonably stable and can be converted to 2,4-dithiothymidine. A hypothesis that involves a cationic pyrimidine intermediate facilitating S_N1 cleavage was proposed.     

Effect of ionic liquid on crystallization kinetics and crystal form transition of poly(vinylidene fluoride) blends

Journal of Thermal Analysis and Calorimetry - Semicrystalline poly(vinylidene fluoride) (PVDF) incorporated with ionic liquids(IL) exhibits applicability as electrolyte. In this paper,...     

Development and validation of a liquid chromatography–tandem mass spectrometry method for the determination of febuxostat in human plasma

A rapid and sensitive analytical method based on liquid chromatography coupled to tandem mass spectrometry detection with positive ion electrospray ionization was developed for the determination of febuxostat in human plasma using d₇‐febuxostat as the internal standard (IS). A simple protein precipitation was performed using acetonitrile. The analyte and IS were subjected to chromatographic analysis on a Capcell PAK C₁₈ column (4.6 × 100 mm, 5 µm) using acetonitrile–5 mm ammonium acetate–formic acid (85:15:0.015, v/v/v) as the mobile phase at a flow rate of 0.6 mL/min. An Agilent 6460 electrospray tandem mass spectrometer was operated in the multiple reaction monitoring mode. The precursor‐to‐product ion transitions m/z 317 → m/z 261 (febuxsotat) and m/z 324 → m/z (261 + 262) (d₇‐febuxostat, IS) were used for quantitation. The results were linear over the studied range (10.0–5000 ng/mL), and the total analysis time for each chromatograph was 3 min. The intra‐ and inter‐day precisions were less than 7.9 and 7.2%, respectively, and the accuracy was within ±4.2%. No evidence of analyte instability in human plasma was observed storage at ?20°C for 31 days. This method was successfully applied in the determination of febuxostat concentrations in plasma samples from healthy Chinese volunteers. Copyright © 2012 John Wiley & Sons, Ltd.     

求解水下纵向加肋无限长非圆柱壳声辐射问题的一种新的半解析方法

基于齐次扩容精细积分法和复数矢径虚拟边界谱方法，利用Fourier积分变换和稳相法，提出了一种具有较高效率和精度的新的求解水下纵向加肋无限长非圆柱壳声辐射问题的半解析方法．考虑了非圆柱壳和肋骨之间同时存在多种相互作用力和力偶矩，较已往很多学者仅计及法向相互作用力更加符合实际．不仅比较了该文方法和精确解计算纵向加肋圆柱壳在集中点力激励下的声辐射计算结果，同时还研究了肋骨数量、大小以及椭圆柱壳横截面椭圆度对声辐射特性的影响．数值计算结果表明该文方法较已有的混合FE-BE法更为有效．     

Silencing of KIF14 interferes with cell cycle progression and cytokinesis by blocking the p27Kip1 ubiquitination pathway in hepatocellular carcinoma

Although it has been suggested that kinesin family member 14 (KIF14) has oncogenic potential in various cancers, including hepatocellular carcinoma (HCC), the molecular mechanism of this potential remains unknown. We aimed to elucidate the role of KIF14 in hepatocarcinogenesis by knocking down KIF14 in HCC cells that overexpressed KIF14. After KIF14 knockdown, changes in tumor cell growth, cell cycle and cytokinesis were examined. We also examined cell cycle regulatory molecules and upstream Skp1/Cul1/F-box (SCF) complex molecules. Knockdown of KIF14 resulted in suppression of cell proliferation and failure of cytokinesis, whereas KIF14 overexpression increased cell proliferation. In KIF14-silenced cells, the levels of cyclins E1, D1 and B1 were profoundly decreased compared with control cells. Of the cyclin-dependent kinase inhibitors, the p27^Kip1 protein level specifically increased after KIF14 knockdown. The increase in p27^Kip1 was not due to elevation of its mRNA level, but was due to inhibition of the proteasome-dependent degradation pathway. To explore the pathway upstream of this event, we measured the levels of SCF complex molecules, including Skp1, Skp2, Cul1, Roc1 and Cks1. The levels of Skp2 and its cofactor Cks1 decreased in the KIF14 knockdown cells where p27^Kip1 accumulated. Overexpression of Skp2 in the KIF14 knockdown cells attenuated the failure of cytokinesis. On the basis of these results, we postulate that KIF14 knockdown downregulates the expression of Skp2 and Cks1, which target p27^Kip1 for degradation by the 26S proteasome, leading to accumulation of p27^Kip1. The downregulation of Skp2 and Cks1 also resulted in cytokinesis failure, which may inhibit tumor growth. To the best of our knowledge, this is the first report that has identified the molecular target and oncogenic effect of KIF14 in HCC.     

Asymmetric Epoxidation of cis/trans‐β‐Methylstyrene Catalysed by Immobilised Mn(Salen) with Different Linkages: Heterogenisation of Homogeneous Asymmetric Catalysis

Immobilised Mn(salen) catalysts with two different linkages were studied in the asymmetric epoxidation of cis/trans‐β‐methylstyrene using NaClO as oxidant. The immobilised Mn(salen) complexes inside nanopores can lead to different catalytic behaviour compared with that of homogeneous Jacobsen catalyst. The rigidity of the linkage was found to be a key factor affecting the catalytic performance of immobilised catalysts. The immobilised catalyst with a rigid linkage exhibited comparable chemical selectivity, enantioselectivity and cis/trans ratio of product formation to that obtained with homogeneous Jacobsen catalysts. In contrast, the immobilised catalyst with a flexible linkage gave remarkably lower chemical selectivity, enantioselectivity and inverted cis/trans ratio compared with the results obtained with the homogeneous Jacobsen catalyst and the immobilised catalyst with rigid linkage. Thus, for immobilised Mn(salen) catalysts, a rigid linkage connecting active centres to the support is essential to obtain activity and enantioselectivity as high as those obtained in homogeneous systems.