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Lithium sulfide (Li2S) is considered to be the best potential substitution for sulfur-based cathodes due to its high theoretical specific capacity (1166 mAh g−1) and good compatibility with lithium metal-free anodes. However, the electrical insulation nature of Li2S and severe shuttling of lithium polysulfides lead to poor rate capability and cycling stability. Confining Li2S into polar conductive porous carbon is regarded as a promising strategy to solve these problems. In this work, N-doped porous carbon microspheres (NPCMs) derived from yeasts are designed and synthesized as a host to confine Li2S. Nano Li2S is successfully entered into the NPCMs’ pores to form N-doped porous carbon microspheres–Li2S composite (NPCMs–Li2S) by a typical liquid infiltration–evaporation method. NPCMs–Li2S not only delivers a high initial discharge capacity of 1077 mAh g−1 at 0.2 A g−1, but also displays good rate capability of 198 mAh g−1 at 5.0 A g−1 and long-term lifespan over 500 cycles. The improved cycling and high-rate performance of NPCMs–Li2S can be attributed to the NPCMs’ host, realizing the strong fixation of LiPSs and enhancing the electron and charge conduction of Li2S in NPCMs–Li2S cathodes.

Cubic boron nitride (cBN) powders with different grain size were used as a starting material, and the pure polycrystalline cubic boron nitride (PcBN) samples were sintered under the same conditions at 7GPa, 1700 °C, 270 s. Abrasion resistance and compressive strength of sintered pure PcBN samples were tested, and the microstructure was observed and analyzed by SEM, HRTEM, XRD and Raman spectrum. The results show that the particle size of cBN has not only a great influence on microstructure and property of the sintered pure PcBN un-der the same conditions but also influence on the bonding mechanism of the cBN particles. The inner stress of the pure PcBN sintered with the cBN particle size of 10 μm during the high pressure sintering process is about 199–222% higher than that of the sample with the cBN size of 1 μm. The wear ratio and the compressive strength of PcBN samples sintered with 10 μm cBN was increased by 47.7% and 39.7% than that of the sintered sample with 1 μm cBN respectively. The coarser-grained PcBN contains serious deformation and crushing, which can be attributed to the twin boundary and the stacking faults in the samples. As a consequence, the abrasion ratio and compressive strength of the pure PcBN are dramatically increased. It is assumed that self-bonding mechanism generated from plasticity deformation, which is a main bonding mechanism for the high pressure sintering of pure cubic boron nitride.

Quantitative dynamic contrast enhanced MRI (DCE-MRI) can offer information related to tumour perfusion and permeability (Ktrans), rate constant (Kep), extravascular extracellular volume fraction (Ve) and distribution volume (Vd). Different types of gadolinium-based contrast agents (GBCAs) may traverse the vascular wall with different velocities owing to their physicochemical characteristics. The purpose of this article was to compare the DCE-MRI quantitative results (Ktrans, Kep, Ve and Vd) between Magnevist and Eovist in a VX2 rabbit liver tumour model. Sixteen rabbits (body weight, 3 Kg; random gender) containing implanted hepatic VX2 carcinomas were randomly divided into two groups based on the regimen of MRI contrast agent administered, eight rabbits in each group. All rabbits underwent a liver DCE-MRscan before tumour transplantation. Fourteen days after tumour transplantation, the eight rabbits in Group A (Magnevist group) underwent a liver DCE-MR scan in a 3.0 T Magnetom Verio MR scanner (Siemens Healthcare, AD, Germany) after the administration of Magnevist at the flow rate of 1 ml s–1. The Group B rabbits underwent the same scan except for the administration of Eovist at the same flow rate. Twenty-four hours after the initial DCE-MRI, repeat DCE-MRI was performed with the cross-over GBCA at the same flow rate in each group. Every rabbit received 0.6 ml GBCA (0.2 ml Kg–1) during each DCE-MRI. Ktrans, Kep, Ve and Vd were measured in the tumour lesion and compared with normal liver tissue in the same slice. A pathologic examination was also performed. Hepatocellular carcinoma was diagnosed in all 16 rabbits by pathologic examination. There were no significant differences in Ktrans, Ve, Kep and Vd between the two groups of rabbits (p > 0.05). The Ktrans, Ve, Kep and Vd of the VX2 rabbit liver tumour model were significantly higher than the normal liver parenchyma (0.742 ± 0.086 vs 0.027 ± 0.002, 7.345 ± 0.043 vs 6.721 ± 0.035, 0.101 ± 0.005 vs 0.101 ± 0.005, 0.419 ± 0.083 vs 0.037 ± 0.005, respectively; p 0.05). In the VX2 rabbit liver tumour model, DCE-MRI performed with different types of GBCA can develop different quantitative results with respect to Ktrans, Ve and Vd. The liver-specific GBCA, Eovist, is more sensitive than the general GBCA, Magnevist, in detecting tumour perfusion and permeability.

Picosecond phase conjugation and two-wave coupling in cerium-doped strontium barium niobate at 778 nm were studied. The phase conjugation reflectivity at 778 nm was measured to be R pc = 58%. It is close to that pumped by a continuous-wave pump source. The temporal width t pc and spectral width δγpc of the phase conjugate pulse were measured to be the same as that of the pump pulse. The intensity coupling gain of two-wave coupling as a function of time delay τD between two beams was also studied.

A new method for measuring electrooptic coefficients of nonlinear crystals has been developed and used to obtain an accurate measurement of r33 and r13 for Strontium Barium Niobate (SBN). An electrooptic modulator was used with a Michelson interferometer for ac modulation (sub-Hz to MHz). By observing the appearance and symmetrical shape of the second harmonic of the ac modulation, the electrooptic coefficients r33 and r13 of SBN were measured with higher accuracy. The unclamped electrooptic coefficients of poled of SrxBa1-xNb2O6 single crystal are: r33=237±3 pm/V and r13=37±1 pm/V, at λ=632.8 nm and T=21°C. In addition the piezoelectric coefficient d23 has been measured with d23=25±5pm/V.

Direct two-photon transitions between the crystal field components of the 3H6 ground state and the 1I6 excited state within the 4f12 manifold of Tm3+: LaF3 have been observed at 77 K. The dependence of the induced fluorescence intensity on the pumping laser intensity agrees with the prediction by two-photon absorption theory. Several new crystal field components of 1I6 were observed from the two-photon transitions of the absorption spectra.