Lateral cavity photonic crystal surface-emitting laser with ultralow threshold

A lateral cavity photonic crystal (PhC) surface-emitting laser is realized on a commercial epitaxial waveguide wafer without a distributed Bragg reflector first. Energy is coupled from the lateral resonance to surface-emitting light through the Γ band edge of the PhC with a square lattice. Electrically driven 1553.8?nm surface-emitting lasing action is observed at room temperature. The threshold current density of 667?A/cm2 is ultralow for the surface-emitting laser.     

Improved surface-enhanced Raman scattering of patterned gold nanoparticles deposited on silicon nanoporous pillar arrays

Large-area silicon nanoporous pillar arrays (Si-NPA) uniformly coated with gold nanoparticles was synthesized, and surface-enhanced Raman scattering of rhodamine 6G adsorbed on these gold nanoparticles were studied and compared. It's found that Au/Si-NPA substrate has a significantly high Raman signal sensitivity and good homogeneity. These are attributed to gold nanoparticles with narrow particle-size distribution uniformly coated on the surface and to the enlarged specific surface area for adsorption of target molecules brought by the porous silicon pillars.     

A novel method for improving the adhesion strength of the electrodeposited Ni films in MEMS

Adhesion performance of MEMS materials is increasingly important with the widely use of miniaturized devices. This paper proposed a novel method for improving adhesion performance between electrodeposited Ni multi-layers. The new method is to treat the Ni substrate in nickel chloride plating solution by pulse reverse current technique before electrodeposition. The dense oxide film of Ni substrate can be removed effectively by this electrochemical method, meanwhile, the proper roughness of Ni substrate is in favor of epitaxial growth during electrodeposition. Moreover, the Ni film is electrodeposited by the new method with low stress and coarse crystal grain. Consequently, the adhesion performance of Ni films is improved dramatically. The experimental results show that the adhesion performance of Ni film electrodeposited by the new method is about 3 times that of by traditional method.     

The research and preparation of a novel nano biodegradable polymer external reinforcement

The use of current drug-loaded vascular scaffolds is limited in sustained drug release and stability studies in clinical and preclinical trials. We found that poly(l-glutamic acid)-b-poly(propylene oxide)-b-poly(l-glutamic acid) (PLGA-b-PPO-b-PLGA) triblock copolymers can deliver multiple poorly water-soluble drugs (e.g., Paclitaxel) at clinically relevant doses. In this study, we synthesized a new drug-loaded vascular external graft with electrospun nanofibrous scaffolds [poly(l-lactide-co-?-caprolactone) (PLCL):fibrinogen; 2:1 (w/w)] and drug-loaded PLGA-b-PPO-b-PLGA micelles. Cell proliferation and viability assay results showed that beagle smooth muscle cells grew well on the surface of vascular graft-coated micelles at a percentages of 10% (w/w) GPG:PLCL-fibrinogen. This study demonstrates that micelle-coated electrospun PLCL-fibrinogen vascular scaffolds have potential applications in vascular tissue engineering.     

The effect of heat treatment on the electrochemical corrosion behavior of reactive plasma-sprayed TiN coatings

The effect of heat treatment on the corrosion behavior of reactive plasma sprayed TiN coatings in simulated seawater was investigated by electrochemical methods such as the corrosion potential-time curve (E_corr − t), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and SEM, etc. The results showed that the corrosion potential of TiN coatings increased after heat treatment; the corrosion current of the TiN coatings after heat treatment (be hereafter referred to as HT-TiN) was 13.3% of the untreated coatings (be hereafter referred to as UT-TiN), and the polarization resistance of HT-TiN was 20 times of UT-TiN, which indicated that the heat treatment had significantly increased the corrosion resistance of the coatings. The corrosion behavior of the coatings was mainly local corrosion, and the local corrosion behavior mainly took place at the microdefects (crack and pores) of the coatings. The porosity of the coatings was reduced after heat treatment. The reason was that TiN reacted with O₂ to form TiO₂ and Ti₃O during the heat treating, and volume expansion took place, which led to denser microstructure. The corrosion resistance of the coatings was therefore increased.     

单目摄像机-激光测距传感器位姿测量系统

在单目视觉测量中,由于模型自身的限制,沿摄像机光轴方向上的位移测量精度一般远低于垂直光轴方向上的位移测量精度.首先,从数学模型上分析了单目视觉位姿测量在沿光轴方向上位移测量精度低的原因;然后,为了提高沿摄像机光轴方向上的位移测量精度,通过在沿摄像机光轴方向上加装一个高精度的激光测距传感器,设计了一种单目摄像机-激光测距...     

质子交换LiNbO3波导调制器多模截止波长的测试技术研究

提出并实验了一种采用倒置输入的结构来测定Y分支LiNbO3波导相位调制器的多模截止波长的新方法,模式耦合分析表明,倒置输入的Y分支波导的多模传输的输出功率具有随波长变动发生振荡的特征,该特征可用于定量判定多模截止波长.方法的有效性得到了波束传播法(BPM)仿真和样品实验两方面的验证.     

角分辨光电子能谱光束线1200line/mm光栅研制

国家同步辐射实验室新建了覆盖5～40 eV的低能区高分辨率角分辨光电子能谱光束线.其球面光栅单色仪包含了三块光栅,即300,600和1200 line/mm球面层式(Laminar)光栅.采用全息离子束刻蚀工艺,在硅光栅基片上成功地刻蚀出1200 line/mm、占空比0.35、槽深35 nm、有效刻划面积大于120 ...     

First-principles study on the electronic structure, magnetic properties and phase stability of alloyed cementite with Cr or Mn

Using the first-principles technique, the electronic structures, magnetic properties and phase stability of alloyed cementite with Cr or Mn were investigated. The calculations show that the chemical and mechanical stability of alloyed cementite can be strengthened by the use of Cr/Mn-doped method. The Magnetic Moments (Ms) of Mn₁Fe₂C, Mn₂Fe₁C, Cr₁Fe₂C and Cr₂Fe₁C are 5.274, 0.941, 1.864 and 0.736 μ_B/f.u, respectively. The Ms of Cr in Fe₂CrC (−1.374 μ_B) and Cr₂FeC (−0.032 μ_B) are different due to replacing different sites Fe atoms. The magnetic behaviors of Mn are different from Cr in alloyed cementite. The Ms of Mn in Fe₂MnC and Mn₂FeC are 2.300 μ_B and −0.147 μ_B, respectively.     

Rectifying and photovoltage characteristics of Bi<Subscript>2</Subscript>Sr<Subscript>2</Subscript>Co<Subscript>2</Subscript>O<Subscript>y</Subscript>/Nb-doped SrTiO<Subscript>3</Subscript> heterojunction

A heterojunction was fabricated by growing a layer of Bi₂Sr₂Co₂O _y thin film on the 0.7 wt% Nb-doped SrTiO₃ substrate. Such heterojunction showed good rectifying characteristics over a wide temperature range, and its transport mechanism under the forward bias can be attributed to a space charge limited conduction mechanism via defects near the interface of the heterojunction. Photovoltaic properties of the heterojunction were studied by using both continuous-wave and pulsed irradiations and the results can be well explained by the photovoltaic effect of a p–n junction.