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Pt–Co bimetallic catalysts were deposited on γ-Al2O3 nanoparticles by atomic layer deposition (ALD) and were used for selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL). High resolution transmission electron microscopy, hydrogen temperature‐programmed reduction, x-ray diffraction, and x-ray photoelectron spectroscopy were used to identify the strong interaction between Pt and Co. The obtained catalysts with an optimal Pt/Co ratio achieved a COL selectivity of 81.2% with a CAL conversion of 95.2% under mild conditions (i.e., 10 bar H2 and 80 °C). During the CAL hydrogenation, the addition of Co on Pt significantly improved the activity and selectivity due to the synergetic effects of Pt–Co bimetallic catalysts, resulted from the transfer of electrons from Co to Pt, which can stabilize the carbonyl groups. The obtained Pt–Co bimetallic catalysts also showed excellent stability due to the strong interaction between the metal nanoparticles and the alumina support. Negligible losses in the activity and selectivity were observed during the recycling experiments, showing the potential for practical applications.

Glass-coated hard-magnetic Fe - Co - Cr microwires were prepared by Taylor's technique with subsequent annealing at different temperatures. The diameter of the metallic core is . The annealing temperature dependence of the coercive force is reported; the maximum coercivity is about 200 Oe after an annealing at for one hour. Such materials may be useful in locally magnetizing devices and magnetic force microscopy.

A new series of the carbides RFe11.35Nb0.65Cy (R identical to Y, Gd, Tb, Dy, Ho or Er) (y approximately=1.0) with the ThMn12 structure was synthesized by gas-solid-phase reaction at 773 K. The unit-cell volumes of the carbides increase upon carbonation by nearly 4.0% across the series. The average enhancement of the Curie temperature is about 160 K. The highest Curie temperature is 733 K for the carbide GDFe11.35Nb0.65Cy. The saturation magnetization of the Fe sublattice is 22.5 mu B FU-1 at 4.2 k and 20.7 mu B FU-1 at room temperature. The maximum value of the anisotropy field found at room temperature for DyFe11.35Nb0.65Cy is about 8 T.

In the present paper, the structure and magnetic properties of TbMn6Sn6 have been investigated. TbMn6Sn6 is found to be of HfFe6Ge6-type structure (space group P6/mmm) with a = 5.5461 Angstrom, c = 9.0477 A and V = 241 Angstrom(3). This compound shows ferrimagnetic behaviour with the ordering temperature T-c = 421 K. A peak is also observed in the thermal magnetic curve at 330 K. Under magnetic fields of 100, 300 and 400 Oe, the magnetization values first increase with increasing temperature, next exhibit a peak and then decrease with further increase in temperature. When the applied magnetic field is sufficiently large, e.g. 1000 and 2100 Oe, the magnetization of the whole sample decreases with increasing temperature. With increasing temperature from the range 77-300 K, the coercivity first increases, next undergoes a peak at about 200 K and then decreases. At room temperature a magnetization jump is observed in the magnetization curves at a field of about 4 kOe in both the aligned and the free powder samples. This jump may be attributed to the spin-flop or metamagnetic transition. The magnetic anisotropy field at room temperature is found to be 8.33 kOe.

The magnetocrystalline anisotropy of YFe12-xMox and YPe12-xMoxNy (x=1-3, y approximately=1) have been investigated by X-ray diffraction and the singular point detection technique. The uniaxial anisotropy of the YFe12-xMox series decreases with increasing Mox concentration with a clear turning point at about x=1.6. The anisotropy characteristic of the nitride YFe12-xMoxNy changes into a canted-type anisotropy for x or=1.5. The anisotropy reduction for YFe12-xMox is mainly due to the substitution of Mox atoms on the 8i sites, while the further change in anisotropy for YFe12-xMoxNy may be due to a change in the 3d orbital moment or to a change in crystal-field interaction by the interstitial Ny atoms.

We report a switching of conducting channel and magnetoresistance (MR) in very thin metallic films deposited on Si substrate with native SiO2 surface. The resistance of the metal-oxide-semiconductor (MOS) structure significantly increases when the temperature is lowered to a threshold value Tc of about 250 K. At room temperature the samples exhibit a high conductivity, and a positive MR of about 18%. Below Tc, the resistivity is increased by ~50% and the positive MR disappears. This effect can be explained by the conducting channel switching from the Si electron inversion layer to the upper metallic films when the temperature is decreased. It has also been found that the MR of Cu80Co20-SiO2-Si structure changes sign with the change of temperature, which is correlated to the switching of the conducting channel.

In this paper, we report wafer-level bonding using solid-liquid inter-diffusion (SLID) processes for fabricating micro-joints Cu–Sn at low temperature (270 °C). The evolution of multilayer Cu/Sn to micro-joint alloys has been characterized by optical microscopy and mechanical die-shear testing. The Cu–Sn joints with line width from 80 to 200 μm prove to be reliable packaging materials for bonding vacuum micro-cavities with controllable Sn overflow, as well as high mechanical strength (>70 MPa). A thermodynamic model has been performed to further understand the formation of Cu–Sn intermetallic alloys. There are two important findings for this work: 1) Using a two-step temperature profile may significantly reduce the amount of Sn overflow; 2) for packaging, a bond frame width greater than 80 μm will result in high yield.

Hard magnetic behaviours of the composite materials (NdDy-FeCo-B)1-xFex prepared by direct mixing of iron nanoparticles with HDDR NdDy-FeCo-B powders have been investigated. With increasing the content of iron nanoparticles in composite materials, the remanence first increases, undergoes a peak and then decreases, whereas the coercivity decreases monotonically. The squareness of the demagnetization curves decreases with increasing content of iron nanoparticles. Meanwhile, a high degree of reversibility in the minor loops along the demagnetization branch in the fields below coercivity has also been observed.

A new thermosetting polymer, modified poly (diallyl phthalate) (PDAP), is used as intermediate layer to realize a void-free wafer-level transfer bonding, in which the bonding interface contains patterned metal. Through glass?silicon bonding experiments, bonding defects are easily recognized with light microscopy. Three typical defect types are identified as: uneven flow defect, particle defect and bubble defect. The processing parameters, such as bonding pressure, pre-baking temperature, polymer thickness and coating conditions, have been optimized based on analysis of the defect formation. The optimized conditions have yielded a void-free wafer-level adhesive bonding. Then, the die shearing test indicates a good bonding strength. Additionally, the transfer bonding process is applied in SOI?silicon bonding as a practical example of MEMS fabrication.

A smart fully integrated micromachined separator with soft magnetic micro-pillar arrays has been developed and demonstrated, which can merely employ one independent lab-on-chip to realize cell isolation. The simulation, design, microfabrication and test for the new electromagnetic micro separator were executed. The simulation results of the electromagnetic field in the separator show that special soft magnetic micro-pillar arrays can amplify and redistribute the electromagnetic field generated by the micro-coils. The separator can be equipped with a strong magnetic field to isolate the target cells with a considerably low input current. The micro separator was fabricated by micro-processing technology. An electroplating bath was hired to deposit NiCo/NiFe to fabricate the micro-pillar arrays. An experimental system was set up to verify the function of the micro separator by isolating the lymphocytes, in which the human whole blood mixed with Dynabeads® FlowComp Flexi and monoclonal antibody MHCD2704 was used as the sample. The results show that the electromagnetic micro separator with an extremely low input current can recognize and capture the target lymphocytes with a high efficiency, the separation ratio reaching more than 90% at a lower flow rate. For the electromagnetic micro separator, there is no external magnetizing field required, and there is no extra cooling system because there is less Joule heat generated due to the lower current. The magnetic separator is totally reusable, and it can be used to separate cells or proteins with common antigens.