Growth and electric properties of (100)-oriented Mn-doped (Bi0.5Na0.5)TiO3-BaTiO3 thin film by pulsed laser deposition

Mn-doped (Bi_0.5Na_0.5)TiO₃-BaTiO₃ (BNBMT) thin film with the composition near the morphotropic phase boundary was grown on (La_0.6Sr_0.4)CoO₃-electroded SrTiO₃ single-crystal substrate by using pulsed laser deposition method. Ascribed to the crystal structure and lattice similarity, (100)-oriented BNBMT film with pure single-phase perovskite structure was obtained through carefully controlling the growth conditions. Enhanced ferroelectric and dielectric properties were obtained with large remanent polarization P _r of ～21 μC/cm², coercive field E _c of ～7.4 kV/mm and dielectric constant $\varepsilon_{33}^{T}/\varepsilon_{0}$ of ～750 at 1 kHz. The excellent global electrical properties of the BNBMT film are promising for environmentally friendly ferroelectric devices.     

Photoluminenscence property of ferromagnetic ZnMnO thin films

High quality Mn doped ZnO thin films were grown on c-plane Al₂O₃ by oxygen plasma assisted molecular beam epitaxy. Photoluminescence spectra were investigated on the ferromagnetic ZnMnO films. An additional emission located at ∼3.32 eV was observed on these ferromagnetic films for both as-grown and oxygen-annealed samples. It is assigned to the recombination of neutral acceptor bound excitons. The ionization energy of the acceptor was estimated to be 53–80 meV. The observed ferromagnetism was explained to relate with acceptor-type defects.     

In Vitro Evaluation of Combined Sulfated Silk Fibroin Scaffolds for Vascular Cell Growth

A combined sulfated silk fibroin scaffold is fabricated by modifying a knitted silk scaffold with sulfated silk fibroin sponges. In vitro hemocompatibility evaluation reveals that the combined sulfated silk fibroin scaffolds reduce platelet adhesion and activation, and prolong the activated partial thromboplastin time (APTT), thrombin time (TT), and prothrombin time (PT). The response of porcine endothelial cells (ECs) and smooth muscle cells (SMCs) on the scaffolds is studied to evaluate the cytocompatibility of the scaffolds. Vascular cells are seeded on the scaffolds and cultured for 2 weeks. The scaffolds demonstrate enhanced EC adhesion, proliferation, and maintenance of cellular functions. Moreover, the scaffolds inhibit SMC proliferation and induce expression of contractile SMC marker genes.

     

LaFe1-xNixO3-δ系陶瓷导电性研究

采用标准的固相反应法制得ＬａＦｅ１－ｘＮｉｘＯ３－δ系陶瓷,用双臂电桥原理、四探针法对材料的电阻率进行测试。结果表明,ＬａＦｅ１－ｘＮｉｘＯ３－δ系陶瓷在０．６〈ｘ〈０．８范围具有金属态导电性,在该系材料中,存在着氧缺位和导电电子,因此具有较高的电子和氧离子混合导电性。制造工艺与氧缺位密切相关,适当提高烧结温度可使室温电阻率降低。温温实验证明,在１２０Ｋ附近材料存在一相变过程。     

Effects of magnetic field orientation and injected current density on the output of nano-structured Co/Cu/Fe junctions

Co/Cu/Fe nano-sized sandwich thin films have been prepared by electron beam evapora- tion. 5 μm ×x 5 μm Co/Cu/Fe sandwich heterojunction was made using photolithography and lift-off process. The bipolar output signal of Co/Cu/Fe junctions has been measured and analyzed. The effects of applied magnetic field angle (referring to the normal of the junction plane) and injecting spin-polarized current on the output signals have been studied, and the measured results were discussed.     

Identification of multiple transient faults based on the adaptive spectral kurtosis method

This paper proposes a multi-fault detection method based on the adaptive spectral kurtosis (ASK) analysis of the vibration signal from single sensor. A theoretical model of multiple bearing faults is established in this paper. Compared with the kurtogram and protrugram techniques, the proposed method can more effectively extract signatures of multiple bearing faults even in the presence of strong background noise. The performance of the proposed method in fault detection of the rolling element bearings is validated using simulation data and experimental signals from a bearing with multiple faults and two faulty bearings.     

A longitudinal (1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 single-crystal piezoelectric transformer

In present work, a simple longitudinal piezoelectric transformer with the size of 16-mm length, 2-mm width, and 2-mm thickness was designed and fabricated with relaxor ferroelectric single-crystal (1−x)Pb(Mg_1/3Nb_2/3)O₃-xPbTiO₃. Both the input and output parts utilized the ultrahigh longitudinal extensional electromechanical coupling coefficients. Compared to the Rosen-type transformer, this transformer has the advantages of smaller-size, simpler structure, no spurious vibration, and no acoustic mismatch between the input and output parts. The electrical measurement results indicated that under the resonance frequency of 114 kHz, a step-up voltage of about 30 can be obtained under a 10-MΩ load resistance, which agreed well with the calculated results. Besides, the frequency and load dependences of this transformer were also systematically studied and discussed. The results indicated that this transformer has potential applications in the small-size high-voltage amplifier and magnetoelectric/piezoelectric-transformer composite transducers.     

Conjugated polymers containing a 2,2'-biimidazole moiety--a novel fluorescent sensing platform

Two novel conjugated polymers containing a 2,2'-biimidazole moiety have been designed, synthesized, and demonstrated to be used as an effective fluorescent sensing platform for detection of Ag(+) and cysteine. This is the first example utilizing a fluorescent conjugated polymer-Ag(+) complex to selectively detect Cys with a nanomolar range detection limit.     

High-performance pyroelectric single crystals for uncooled infrared detection applications

Uncooled pyroelectric infrared detectors based on ferroelectric single crystals 0.74Pb(Mg_1/3Nb_2/3)O₃–0.26PbTiO₃ (PMN–0.26PT) were fabricated. The performances of pyroelectric detectors dependence on detector fabrication temperature, absorption layer, and element thickness were compared. The room-temperature voltage responsivity (R_v) of 200 V/W and specific detectivity (D^*) of 10⁸ cm Hz^1/2/W at 12.5 Hz have been achieved. The results reveal that the better pyroelectric response can be expected by controlling temperature below 70 °C during the fabrication of the pyroelectric detectors, selecting absorption layer with high absorption coefficient, and decreasing the thickness of the elements.