Coherent manipulation of spin squeezing in atomic Bose-Einstein condensate via electromagnetically induced transparency

We propose a scheme to coherently control spin squeezing of atomic Bose-Einstein condensate (BEC) via the technique of electromagnetically induced transparency (EIT). We study quantum dynamics of the mean spin vector and spin squeezing. It is shown that the mean spin vector and spin squeezing of the BEC can be controlled and manipulated by adjusting the external coupling fields or/and internal nonlinear interactions of the BEC. It is indicated that the spin squeezing can be generated rapidly in the dynamical process and maintained in a long time interval. It is found that a larger effective Rabi coupling between atoms and lasers can produce a stronger spin squeezing, and the squeezing can maintain a longer time interval.     

微波单片电路中通孔的建模

分析了理论公式在计算截圆锥通孔电感中的局限性.设计了频率在20 GHz以下GaAs基微波单片电路中通孔的专门测试结构并建立了其对应的等效电路,用去嵌入寄生参数的方法和安捷伦公司标准的IC-CAP建模系统提取了通孔的模型参数.发现对截圆锥结构的通孔,用公式计算出来的通孔的电感值比实验的结果大36%.设计了一个14-18 GHz、增益大于17 dB、输出功率为1W的GaAs基微波单片电路,验证了模型的准确性.     

ZnS/g-C3N4复合型催化剂的制备及其可见光光催化性能

利用共沉淀的方法制备了ZnS/g-C3N4复合型催化剂,并考察其在可见光区对罗丹明B的光降解性能的影响机制.采用TEM、BET、XRD、ICP、FT-IR和XPS等分析手段表征了样品,并评价了样品的光催化活性.结果表明,与g-C3N4相比,ZnS负载量为5wt;的ZnS/g-C3N4催化剂活性会更高一些,且经过四次循环实验后样品的光催化性能未明显失活.这可能归因于ZnS和g-C3N4所形成的异质结构提高了光催化效率.     

薄膜多层布线工艺分析

薄膜多层布线工艺，采用聚酰亚胺作介质，克服成膜后的“龟裂”、减少通孔的接触电阻和防止“断台”问题，是解决好介质质量的关键。     

Novel sparse component analysis approach to free radical EPR spectra decomposition

Free radicals play important roles in many physiological and pathological pathways in biological systems. These free radicals can be detected and quantified by their EPR spectra. The measured EPR spectra are often mixtures of pure spectra of several different free radicals and other chemicals. Blind source separation can be applied to estimate the pure spectra of interested free radicals. However, since the pure EPR spectra are often not independent of each other, the approach based on independent component analysis (ICA) cannot accurately extract the required spectra. In this paper, a novel sparse component analysis method for blind source separation, which exploits the sparsity of the EPR spectra, is presented to reliably extract the pure source spectra from their mixtures with high accuracy. This method has been applied to the analysis of EPR spectra of superoxide, hydroxyl, and nitric oxide free radicals, for both simulated data and real world ex vivo experiment. Compared to the traditional self-modeling method and our previous ICA-based blind source separation method, the proposed sparse component analysis approach gives much better results and can give perfect separation for mixtures of superoxide spectrum and hydroxyl spectrum in the ideal noise-free case. This method can also be used in other similar applications of quantitative spectroscopy analysis.     

Uranium internal contamination studies. Biodistribution, retention and elimination

Using the U fission track micromapping technique, the uranium biodistribution, retention and elimination for four Wistar-London breed rats simultaneously contaminated with U entering via nose were investigated. At different durations after contamination, the rats were sacrified: one of them immediately and the others in a day, 9 days and 36 days, respectively. Their vital parts, in soft tissue and calcined states, as well as their calcined evacuations which were sampled every 24 hours were analysed by the fission track method. Using the optical microscopy, the obtained U track micromappings were studied in order to determine both the U contents and distributions in the analysed samples. The U contents determinations in the analysed organs and evacuations are given in the paper.     

海洋杂波对高频雷达检测海面上低速目标的影响

由BarrickHF雷达海洋回波散射截面方程出发，求出单位波束宽、单位海域的海浪回波散射截面。并用一天线口径为25km，分辨率为1．5km的雷达系统，研究了海来波对HF雷达检测海面上雷达截面积为30dBm2的小船目标和50dBm2的大船目标的影响。     

利用扫描电子显微镜改进GaAs MESFET背面通孔电镀工艺

利用扫描电子显微镜对ＧａＡｓＭＥＳＦＥＴ背面通孔形貌及电镀状况进行了分析，并对电镀工艺进行了改进。给出了大量改善前后的电镜照片图形。     

Electrical Characteristics of the Three-Dimensional Interconnection Structure for the Chip Stack Package with Cu through Vias

A chip stack specimen of a three-dimensional (3-D) interconnection structure with Cu vias of 75-μm diameter, 90-μm height, and 150-μm pitch was successfully fabricated using via hole formation with deep reactive ion etching (RIE), Cu via filling with pulse-reverse pulse electroplating, Si thinning, Cu/Sn bump formation, and flip-chip bonding. The contact resistance of a Cu/Sn bump joint and Cu via resistance could be determined from the slope of the daisy chain resistance versus the number of bump joints of the flip-chip specimen containing Cu vias. When the flip chip was bonded at 270°C for 2 min, the contact resistance of a Cu/Sn bump joint of 100-μm diameter was 6.74 mΩ, and the resistance of a Cu via of 75-μm diameter and 90-μm height was 2.31 mΩ. As the power transmission characteristics of the Cu through via, the S₂₁ parameter was measured up to 20 GHz.     

Wafer-Lever Hermetic Package with Through-Wafer Interconnects

This paper reports a new wafer-level hermetic packaging structure with the features of low processing cost and high I/O density by using wet and dry sequentially etched through-wafer vias for the interconnects of a microelectro mechanical systems (MEMS) device. A thin Si wafer cap and wafer-level fabrication processes such as deep reactive ion etching (DRIE) and KOH etching, bottom-up copper filling, and Sn solder bonding were adopted. The hermeticity and bonding strength of the structure are evaluated. Preliminary results show that the hermeticity can meet the requirement of the criterion of MIL-STD 883E, method 1014.9, and the bonding strength is up to 8 MPa.