Aqueous-Phase, Palladium-Catalyzed Suzuki Reactions under Mild Conditions

Water-soluble ionic liquid-supported diols have been used as phosphine-free ligands in Suzuki couplings of aryl idides/bromides/chlorides under mild conditions in aqueous solvent. It was found that 2,2-bis((1-hexylimidazolium)-mehyl) propane-1,3-diol hexafluorophosphate (4) in combination with palladium (II) salts gave the most significant catalyst. Suzuki couplings of aryl iodides/bromides occurred efficiently at room temperature in water/acetonitrile. Notably, the reactions of hydrophilic aryl bromides gave high yields in neat water. The catalyst PdCl2-4 was recycled five times in Suzuki couplings in water before catalyst activity began to significantly drop. The average yield of five cycles was >95% per cycle.

Assimilation of HY-2A scatterometer sea surface wind data in a 3DVAR data assimilation system-A case study of Typhoon Bolaven

The scatterometer （SCAT） on-board China＇s HY-2A satellite has the capability to provide high resolution wind vector information over the global ocean surface. These wind vector data produced by the HY-2A scatterometer （HY-2A SCAT） are available to the data assimilation system with real-time information of high accuracy. In this paper, two experiments are designed to investigate the impact of HY-2A SCAT data in the three- dimensional variational assimilation system for the Weather Research and Forecast model （WRF 3DVAR）. The powerful Typhoon Bolaven, which struck South Korea in August 2012, is selected for this case study. The results clearly demonstrate that HY-2A SCAT data can effectively complement the scarce observations over the ocean surface and improve the prediction of the wind and pressure fields of a typhoon. The case study of Typhoon Bolaven exhibits the significant and positive impact of HY- 2A SCAT data on the numerical prediction of the tropical cyclone track.

Magnetic properties and microstructure of Fe69.5-xNd7B21Nb2.5Gax（x=0-1）alloys

The Fe69.5-xNd7 B21Nb2.5Gax(x = 0-1)permanent magnets in the form of rods were prepared by annealing the bulk amorphous alloys.The magnetic properties,phase evolution and microstructure of the alloys were investigated systematically.It is found that the glass forming ability(GFA), microstructure and magnetic properties are sensitive to Ga content for Fe69.5-xNd7 B21Nb2.5Gax(x = 0-1)bulk alloys.The annealed alloys are mainly composed of soft α-Fe,hard Nd2 Fe14B and nonmagnetic Nd1.1Fe4 B4 phases.When x = 0.3,the optimally annealed magnets exhibit magnetic properties of the remanence Br = 0.63 T,intrinsic coercivity Hcj = 368.68 kA/m and maximum energy product(BH)max = 33.73 kJ/m3.Furthermore,magnetic field heat treatment at the temperature close to Curie temperature of Nd2 Fe14B phase was applied to the annealed Fe69.2Nd7 B21Nb2.5Ga0.3 magnet.The results of X-ray diffraction(XRD)and transmission electron microscopy(TEM)indicate that the magnetic field heat treatment can be beneficial for the precipitation of α-Fe.Thus,the Br,Hcj and(BH)max are enhanced by 8.7%,6.3% and 16.3%,respectively.

Enhanced magnetic properties of Ce_(17)Fe_(76.5)Co_1Zr_(0.5)B_6 alloys by magnetic field heat treatment

In the present work,Ce_(17)Fe_(76.5)Co_1Zr_(0.5)B_6 ribbons were prepared by a direct melt spinning method.The effects of chamber pressure and magnetic field annealing temperature on the magnetic properties and microstructures of the alloys were investigated.The grain size and content of Ce_(2)Fe_(14)B phase can be changed by adjusting the chamber pressure,and the optimal magnetic performance is obtained at0.04 MPa.The magnetic properties can be influenced under magnetic field heat treatment.When the annealing temperature is lower than the Curie temperature,the refinement and a uniform distribution of the grains is obtained.The irreversible magnetic susceptibility curve reveals that magnetic field heat treatment enhances the exchange coupling interaction between grains of the Ce_(2)Fe_(14)B phase.When the magnetic field annealing temperature is 438 K,the alloy displays the optimal magnetic properties.Compared with the as-spun sample,the values of intrinsic coercivity(H_(ci)),remanence(B_r) and maximum energy product((BH)max) increase by 3.4%,9.8% and 18.7%,respectively.This work provides an effective approach by which to enhance the magnetic properties of Ce-Fe-B alloys.