Cu2O-Catalyzed Conversion of Benzyl Alcohols Into Aromatic Nitriles via the Complete Cleavage of the C≡N Triple Bond in the Cyanide Anion

Nitrogen transfer from cyanide anion to an aldehyde is emerging as a promising method for the synthesis of aromatic nitriles. However, this method still suffers from a disadvantage that a use of stoichiometric Cu(II) or Cu(I) salts is required to enable the reaction. As we report herein, we overcame this drawback and developed a catalytic method for nitrogen transfer from cyanide anion to an alcohol via the complete cleavage of the C≡N triple bond using phen/Cu₂O as the catalyst. The present condition allowed a series of benzyl alcohols to be smoothly converted into aromatic nitriles in moderate to high yields. In addition, the present method could be extended to the conversion of cinnamic alcohol to 3-phenylacrylonitrile.     

Na3V2(PO4)3/C nanofiber bifunction as anode and cathode materials for sodium-ion batteries

Journal of Solid State Electrochemistry - Na3V2(PO4)3/C composite nanofibers are prepared successfully through a coaxial electrospinning technique and subsequent calcination. The diameter of the...     

SHP2 is a target of the immunosuppressant tautomycetin

SHP2 phosphatase is a positive transducer of growth factor and cytokine signaling. SHP2 is also a bona fide oncogene; gain-of-function SHP2 mutations leading to increased phosphatase activity cause Noonan syndrome, as well as multiple forms of leukemia and solid tumors. We report that tautomycetin (TTN), an immunosuppressor in organ transplantation, and its engineered analog TTN D-1 are potent SHP2 inhibitors. TTN and TTN D-1 block T?cell receptor-mediated tyrosine phosphorylation and ERK activation and gain-of-function mutant SHP2-induced hematopoietic progenitor hyperproliferation and monocytic differentiation. Crystal structure of the SHP2?TTN D-1 complex reveals that TTN D-1 occupies the SHP2 active site in a manner similar to that of a peptide substrate. Collectively, the data support the notion that SHP2 is a cellular target for TTN and provide a potential mechanism for the immunosuppressive activity of TTN. Moreover, the structure furnishes molecular insights upon which therapeutics targeting SHP2 can be developed on the basis of the TTN scaffold.     

泡沫金属夹芯梁在重复冲击下的动态响应

为了研究重复冲击载荷作用下泡沫金属夹芯梁的动态响应,采用Abaqus数值仿真软件,基于可压碎泡沫模型（crushable foam）,建立了泡沫金属夹芯梁遭受楔形质量块冲击的有限元模型。通过将仿真获得的夹芯梁上下面板最终挠度与重复冲击实验结果进行对比,验证仿真方法的准确性。在此基础之上,分析了泡沫金属夹芯梁在楔形质量块重复冲击作用下的变形模式、加卸载过程以及能量耗散特性。结果表明,在重复冲击载荷作用下,夹芯梁的变形不断累积,上面板主要出现局部凹陷和整体弯曲,而芯层则是局部压缩,下面板表现为整体弯曲。在重复加卸载过程中,加卸载刚度随着冲击次数的增加而增大。随着冲击次数的增加,上面板和芯层的能量吸收增量不断减小,而下面板的能量吸收增量不断增加,且最终均趋于稳定。泡沫金属夹芯梁的塑性变形能增量不断减小,而回弹系数随着冲击次数逐渐增加,最后趋于稳定值。     

一种基于BOTDA与FBG传感的共线温度测试技术

根据大型结构全尺度分布式高精度温度测量要求,组合应用布里渊时域分析(BOTDA)技术和光纤布拉格光栅(FBG)温度传感技术,设计了一种由BOTDA分析仪、FBG解调仪、共线传感探头和光开关组成的温度传感测试系统。实验测试证明,该系统具备大范围分布式温度测量与局部高精度温度测量功能,而且实现了BOTDA测温技术与FBG温度传感技术的有效互补,解决了测量范围和测量精度的矛盾问题,并且具有良好的温度重复性,达到了预期的设计要求。该共线测试技术方案在大规模结构温度监测中具有广阔的应用前景。     

关于薄壁曲梁与直梁解析解的进一步讨论

薄壁曲梁的受力问题通常利用弹性力学平面问题的极坐标解法求解,其解法与直角坐标系下直梁受力问题的求解有着异曲同工之处。结果表明,当曲梁的曲率半径趋近于无限大时,可以得到直梁问题的解,从而展示了曲梁与直梁受力问题的内在联系。

     

新型气流声源发声特性及其对气溶胶的团聚 实验研究*

为提高气溶胶颗粒物的声波团聚效果,创新性地设计了一种具有气声分离特性的气流声源。新声源使乏气从侧面开口排出,避免了对团聚效果的影响。通过实验研究了侧面开口尺寸对号角出口处气流量与声压级的影响,发现侧面开口尺寸对乏气排出及声压级有较大影响,当侧面开口尺寸约为6.5 mm时排气效果较好,此时在0.3 MPa驱动压力下声压级可达159.6 dB,同时乏气已基本全部从侧面开口排出。利用该声源对超细液滴气溶胶进行团聚实验,结果显示,声源驱动压力越大,声压级越大,气溶胶受声场作用力越强,颗粒间碰撞几率增大,团聚速率越快;初始气溶胶浓度越高,前期团聚效果越好,透光率增长速度越大,而后期团聚效果则趋近一致。     

Analysis of circular bends in planar optical waveguides

Waveguides with circular bends are analyzed by means of a conformal transformation in conjunction with the WKB method of dealing with the nonuniform refractive index that results from the transformation. The result is a prediction of the operational parameters of the bent guide, including the loss. The transformation makes possible an intuitive understanding of the cause of the loss.     

一种考虑声线弯曲的温度场重建算法

声波在非均匀温度场中传播时会由于声波的折射而产生声线弯曲现象。为提高非均匀温度场声学CT (Computer Tomography)重建精度,提出一种考虑声线弯曲的重建算法。首先用最小二乘法获得一个不考虑声线弯曲的重建温度场,然后用打靶-插值法确定本征声线出射角,用三角形前向展开法追踪声线,获得此温度场中声波发射/接收器间的本征声线,建立本征声线上声波传播时间与温度分布间的关系,进而实现考虑声线弯曲的最小二乘法温度场重建。单峰、双峰温度场仿真重建结果表明:所采用的本征声线追踪法计算简单运行速度快;考虑声线弯曲后,可明显提高温度场重建精度。因此所提重建算法能更好地适应实际温度场重建需求。     

Analysis of circular bends in planar optical waveguides

Waveguides with circular bends are analyzed by means of a conformal transformation in conjunction with the WKB method of dealing with the nonuniform refractive index that results from the transformation. The result is a prediction of the operational parameters of the bent guide, including the loss. The transformation makes possible an intuitive understanding of the cause of the loss.