用电子束曝光方法在优化设计的绝缘体上硅脊状波导上实现布拉格光栅的制作和评价

报道了一种用电子束曝光的方法在绝缘体上硅的脊状光波导上制做布拉格光栅的技术.考虑到实际的光子学集成的应用,讨论了这个带有布拉格光栅的脊状光波导的优化设计,给出了该布拉格光栅的测试和理论模拟结果.通过薄化绝缘体上硅的波导层的厚度和光栅的深腐蚀加工,获得了高达30cm-1的光栅耦合系数.     

AlGaAs/GaAs lateral current injection multiquantum well (LCI-MQW)laser using impurity-induced disordering

A lateral current injection (LCI) multiquantum-well (MQW) laser having planar structure is proposed and its advantages compared with conventional vertical structure lasers. A LCI-MQW laser has been fabricated by using Si- and Zn-induced disordering of an MQW active layer. It is shown that a threshold current of 27 mA is achieved under pulsed current driven at room temperature and a very low stray capacitance of 0.27 pF is obtained at zero bias voltage     

40 Gbit/s packet bit error ratio and loss real-time measurement for ultrahigh-speed packet switched network

A novel packet bit error rate (BER) and loss measurement method and system is proposed. A proposed 40 Gbit/s packet BER and loss measurement system is expressed in detail. A 40 Gbit/s BER and loss measurement with various conditions is demonstrated experimentally. In real time, only the payload part of a packet and burst stream with fluctuated guard time is evaluated. The BER and packet loss of a randomly received packet sequence due to routing and buffering can be also evaluated by the measurement system. A 10 Gbit/s packet BER and loss measurement with optical label switching, buffering, and preamble-free optical packet 3R are demonstrated experimentally.     

Pd20Pt20Cu20Ni20P20 high-entropy alloy as a bulk metallic glass in the centimeter

A Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ bulk metallic glass (BMG) with a high-entropy (HE) alloy composition and a maximum diameter of 10 mm was fabricated by fluxed water quenching. The system and composition of the Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ alloy were determined from a prototype ternary Pd₄₀Ni₄₀P₂₀ BMG in accordance with two strategic alloy designs of (1) HE alloy defined by an equi-atomic alloy with five or more elements and (2) exchangeability of the constituent elements with a similar chemical nature in the periodic table. Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ HE-BMG had a supercooled liquid range of 65 K and a reduced glass transition temperature of 0.71. Successful formation of Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ HE-BMG is significant to develop new alloys for HE alloys and BMGs.     

Highly reliable copper dual-damascene interconnects with self-formed MnSi/sub x/O/sub y/ barrier Layer

Copper (Cu) dual-damascene interconnects with a self-formed MnSi/sub x/O/sub y/ barrier layer were successfully fabricated. Transmission electron microscopy shows that approximately 2-nm thick and continuous MnSi/sub x/O/sub y/ layer was formed at the interface of Cu and dielectric SiO/sub 2/, and that no barrier was formed at the via bottom because no oxygen was at the via bottom during annealing. No leakage-current increase was observed, and electron energy loss analysis shows that no Cu was in SiO/sub 2/, suggesting that MnSi/sub x/O/sub y/ layer has sufficient barrier properties for Cu, and that the concept of self-forming barrier process works in Cu dual-damascene interconnects. Via chain yield of more than 90% and 50% reduction in via resistance were obtained as compared with physical vapor deposited tantalum barrier, because there is no barrier at the via bottom. In addition, no failure in the stress-induced voiding measurement was found even after a 1600-h testing. No failure in electromigration (EM) testing was found, as the electron flow is from the lower level interconnects through via up to upper level interconnects even after 1000-h testing. At least, four times EM lifetime improvement was obtained in the case of electron flow from upper level interconnect through via down to lower level interconnects. Significant EM lifetime improvement is due to no flux divergence site at the via bottom, resulting from there being no bottom barrier at the via.     

Design of a spotsize-converter-integrated laser diode (SS-LD) witha lateral taper, thin-film core and ridge in the 1.3-μm-wavelengthregion based on the 3-D BPM

In order to develop spotsize-converter-integrated laser diodes (SS-LDs) with high efficiency and large-misalignment tolerances in the 13-μm-wavelength region, spotsize converters (SSCs), which consist of lateral taper, thin-film core and ridge, are investigated employing the three-dimensional (3-D) semivectorial finite-difference beam propagation method (FD-BPM) with nonequidistant discretization. The sum of the spot-conversion loss and coupling loss between the laser diode (LD) eigenmode and the single-mode fiber (SMF) eigenmode are calculated for various structural parameters. Small loss of around 1.5 dB can be achieved by introducing a nonlinear taper. The fabrication tolerances for the SSCs are also clarified. The calculated results agree well with the results for actually fabricated SS-LD's. It is also shown that the radiation loss and coupling characteristics of the SS-LDs with a buried thin-film core structure can be improved using a nonlinear taper     

Influence of Y2O3 distribution on the rate of tetragonal to monoclinic phase transformation of yttria-stabilized zirconia during hydrothermal aging

Tetragonal to monoclinic phase transformation of yttria-stabilized zirconia, namely plasma-sprayed coatings and sintered bodies containing 4–8 mass % Y₂O₃ during hydrothermal aging was investigated with respect to Y₂O₃ distribution using 1 m area from electron probe microanalysis (EPMA) and 20 nm area from transmission electron microscopy (TEM) analysis. Phase transformation at 473 K was prevented only in plasma-sprayed coatings having more than 6.7 mass % Y₂O₃ in 20 nm microscopic area. Furthermore, it was confirmed influence of Y₂O₃ distribution on the rate constants of this phase transformation was observed at 368 K.     

Percutaneous bile duct drainage; experiences with a new type of endoprosthesis]

Self expandable stents were placed percutaneously in 105 patients with malignant biliary obstruction. Stent diameter was 1 cm; length, 3.5-10.5 cm. Of the 60 patients with common bile duct obstruction, 50 died 0.2-12 months (median 3 months) after stent insertion. Two patients developed recurrent jaundice and cholangitis after 6 and 12 months, respectively. One patient underwent reintervention. Ten patients, one after a successful reintervention, were alive without jaundice 1-8 months (median 5 months) after stent placement. Of the 45 patients with hilar lesions, 26 died 0.7-18 months (median 5 months) after stent placement, five of them with signs of cholangitis. Nineteen are alive 1-21 months (median 7 months) afterwards. Reinterventions were carried out in 13 patients (29%). The most common cause of stent malfunction was tumour overgrowth. Stent-related complications were seen in three patients.     

Antimicrobial activity in the skin of the channel catfish Ictalurus punctatus: characterization of broad-spectrum histone-like antimicrobial proteins

BACKGROUND: A major reduction in the energy demand of the myocardium results from the electromechanical arrest, and cooling contributes to a lesser degree to this reduction. It is from this assumption that strategies of myocardial protection, utilizing warm blood cardioplegic induction, followed by cold cardioplegia with terminal warm reperfusion before removal of the aortic cross clamp, became established as optimal myocardial protection. Continuous normothermic perfusion 'closed the loop' by avoiding myocardial ischemia and linking warm induction and terminal reperfusion. A series of laboratory and clinical data confirmed the benefits of warm heart surgery on myocardial function and metabolism. The disadvantages of continuous warm blood cardioplegia including disturbance of the operative field, led surgeons to administer warm hyperkalaemic blood intermittently as a new cardioplegic strategy. METHODS: This review examines the laboratory and clinical data with reference to the intermittent warm blood cardioplegia, to establish its experimental basis and place in clinical practice. CONCLUSIONS: Experimental observation and clinical application have established intermittent warm blood cardioplegia as a practical, effective and cheap myocardial protection technique, particularly with reference to coronary artery surgery.