Numerical simulation of unsteady interaction of centrifugal impeller with its diffuser using Lagrangian discrete vortex method

In this study, an advanced Lagrangian vortex- boundary element method is applied to simulate the unsteady impeller-diffuser interactions in a diffuser pump not only for design but also for off-design considerations. In velocity calculations based on the Biot-Savart law we do not have to grid large portions of the flow field and the calculation points are concentrated in the regions where vorticity is present. Lagrangian representation of the evolving vorticity field is well suited to moving boundaries. An integral pressure equation shows that the pressure distribution can be estimated directly from the instantaneous velocity and vorticity field. The numerical results are compared with the experimental data and the comparisons show that the method used in this study can provide us insight into the complicated unsteady impeller-diffuser interaction phenomena in a diffuser pump.     

Highly enantioselective synthesis of silahelicenes using Ir-catalyzed [2+2+2] cycloaddition

Silahelicenes, which contain two silole moieties in a helically chiral structure, were synthesized by a chiral Ir-catalyzed intermolecular [2+2+2] cycloaddition of tetraynes with diynes along with a Ni-mediated intramolecular [2+2+2] cycloaddition. The photophysical properties of the obtained highly enantiomerically enriched silahelicenes (up to 93% ee) were also measured.     

A new and unusually flexible route to cyclopentanoids synthesis of sarkomycin and prostaglandins

Combination of the dianion of dialky 3-hexenedioate and β-bromopropionate leads directly to a 2,3-disubstituted cyclopentanone, which can be transformed to a variety of primary prostaglandins and sarkomycin.     

Conjugate additions of the crown-potassium enolate complexes

Achiral and chiral crowns complexed with potassium bases catalyze the Michael additions of enolates to cycloalkenones.     

Anomalous superconductivity and pressure induced phase transitions in black phosphorus

Pressure induced superconductivity in black phosphorus was measured along three different paths in P-T diagram. High-Tc was observed when pressure was continuously increased at liquid helium temperature. Pressure induced phase transitions has been also studied. A mechanism of the phase transition is closely related to the anomalous superconductivity. The high-Tc superconductivity of black-P may be attributed to the existence of superconducting phase in metallic phase.     

聚（N—十二烷基—3—苯基吡咯）的研究

合成了一种吡咯的双取代衍生物：Ｎ－十二烷基－３－苯基吡咯，并用化学氧化法对其实施了聚合反应。该反应生成的导电聚合物可溶于一般有机溶剂，用溶剂蒸发制膜的方法可制得柔软的自支撑薄膜，用四电极方法测得掺杂态薄膜的电导率约为０．０５Ｓ／ｃｍ。并通过元素分析、ＧＰＣ、ＦＴ－ＩＲ、１Ｈ－ＮＭＲ等手段对其分子结构进行了表征。     

A conductometric method for colloid titrations

A negative or positive colloid sample solution can be directly titrated, respectively, with a polycationic (poly-N, N-diallyldimethylammonium chloride) or polyanionic (potassium polyvinylsulfate) titrant to a conductometric end-point. With the conventional toluidine blue indicator method a positive colloid solution is titrated directly with a polyanionic titrant, but a negative colloid solution must be treated with an excess of a polycationic titrant, which is back-titrated with the polyanionic titrant. For positive colloid solutions, both indicator and conductometric methods are suitable; for negative colloids the conductometric method is preferable because of its constant titration vlues over a range of pH values.     

Rhodium-catalyzed enantioselective [2+2+2] cycloaddition of diynes with unfunctionalized alkenes

A chiral rhodium complex catalyzed an enantioselective [2+2+2] cycloaddition of unsymmetrical diynes with norbornene, and tetracyclic products were obtained in good to excellent ee. The cycloaddition of a symmetrical diyne with styrene derivatives as coupling partners gave bicyclic products in good ee.