Edge-spreading lithography: use of patterned photoresist structures to direct the spreading of alkanethiols on gold

Edge-spreading lithography (ESL) has been extended to fabricate gold structures with different geometries and feature sizes on silicon substrates. In the present variant of ESL, we used photoresist structures patterned on a thin film of gold to transport alkanethiol molecules from an elastomeric stamp to the gold surface where they formed a self-assembled monolayer (SAM) along the edge of each resist feature. The emerging SAM could expand laterally on the gold via reactive spreading, during which the footprints of the resist structures were enlarged in the same fashion. Upon removal of the photoresist, selective etching of gold revealed those regions that were protected by the SAM, yielding accurate outlines of the resist features on the substrate. The width of resultant gold structures was determined by the distance over which the monolayer expanded during spreading, and could be conveniently controlled well below 200 nm by varying the contact time and/or the concentration of alkanethiol in the ink.     

Narrow-channel-spacing 32-channel AWG multiplexer with an innovative alignment method

A 32-channel 50 GHz spaced arrayed-waveguide grating（AWG） with our innovative configuration has been designed and fabricated. The performance of the device has been fully tested by using a system that consists of a tunable laser light source （TLS）, an optical power meter and a polarization controller. The insertion loss （IS） of the device is 4.2-7.4 dB. The crosstalk is about - 28 dB. The IS uniformity is less than 3.3 dB. With our configuration,the performance of the device has been enhanced effectively and the difficulty in alignment process has been decreased obviously.     

Application-aware NoC management in GPUs multitasking

The Journal of Supercomputing - Current network-on-chip (NoC) designs in GPUs are agnostic to application requirements, and this leads to wasted performance in GPUs multitasking. We observe that...     

An image thresholding approach based on Gaussian mixture model

Pattern Analysis and Applications - Image thresholding is an important technique for partitioning the image into foreground and background in image processing and analysis. It is difficult for...     

Improved RIP-based performance guarantees for multipath matching pursuit

The multipath matching pursuit (MMP) is a generalization of the orthogonal matching pursuit (OMP), which generates multiple child paths for every candidate in each iteration and selects the candidate having the minimal residual as the final support set when iteration ends. In this paper we analyze its performance in both noiseless and noisy cases. The restricted isometry property (RIP)-based condition of MMP that ensures accurate recovery of sparse signals in the noiseless case is derived by using a simple technique. The performance guarantees of the MMP for support recovery in noisy cases are also discussed. It is shown that under certain conditions on the RIP and minimum magnitude of nonzero components of the sparse signal, the MMP will exactly recover the true support of the sparse signal in cases of bounded noises and recover the true support with a high probability in the case of Gaussian noise. Our bounds on the RIP improve the existing results.     

Quantifying the spatial and temporal relationship between air and land surface temperatures of different land-cover types in Southeastern China

Near surface air temperature (T_a) is an important variable utilized for various fields of research such as agriculture, epidemic forecasting, and climate change. It is usually obtained from a limited number of weather stations that are unevenly distributed within a region. Thus, the spatial information of T_a is rarely provided especially in complex topographical and underdeveloped regions. To compensate for this shortcoming, T_a can be estimated by using the land surface temperature (T_s) from satellite data because remote sensing has an advantage of describing the spatial heterogeneity over a large geographical area. In previous research, authors focused on analysing the effect of limited factors on T_a observations by using a small number of weather stations. However, this study explores a thorough sensitivity analysis of several factors on the relationship between T_a (obtained from a dense network of automatic weather stations) and T_s of different land-cover types using statistical analysis. This article discovered the relationships between T_a and T_s. First, comparisons between daytime and night-time Moderate Resolution Imaging Spectroradiometer (MODIS) T_s data with T_a data showed that a better agreement was achieved during the night than the day. Second, when comparing the results of different land-cover types, the correlation coefficient of the vegetated area was higher than that of water and impervious surface. Third, a comparison of statistical results for different seasons indicated that the correlation between T_a and T_s was weakest in a hot season. Fourth, altitude seemed to have no significant effect on the T_a–T_s relationship. Finally, the relationship between T_a and T_s strengthened with increasing window size except for the vegetated area but tended to saturate as the T_s window increased to the optimal size. These results will be helpful for building an appropriate model to derive air temperature directly from the remotely sensed data in the future.     

Microstructural topology optimization of structural-acoustic coupled systems for minimizing sound pressure level

The aim of this paper is to present a microstructural topology optimization methodology for the structural-acoustic coupled system. In the structural-acoustic system, the structure is considered to be a thin composite plate composed of periodic uniform microstructures. The discrete design variables are used in the microstructural topology optimization, and the constitutive matrix is interpolated by the power-law scheme at the micro scale. The equivalent macro material properties of the microstructure are computed through the homogenization method. The design objective is to minimize the sound pressure level (SPL) in an interior acoustic medium. The sensitivities of the SPL with respect to design variables are derived. The bi-directional evolutionary structural optimization (BESO) method is extended to solve the structural-acoustic coupled optimization problem to find the optimal material distribution of the microstructure. Numerical examples of a hexahedral box and an automobile passenger compartment are given to demonstrate the efficiency of the presented microstructural topology optimization method.     

岩石高边坡爆破开挖对锚固设施的影响

本文根据在黄河李家峡工程施工中开展的现场试验 ,就岩石高边坡开挖时 ,爆破动荷载对已设置的边坡预应力锚杆锚索 (及锚筋桩 )等锚固设施的影响进行了研究。采用多种测试方法 ,如加速度、动应变、动应力等追踪了爆破动荷载对它们的作用过程及其影响 ,分析了其瞬时增荷及预应力受损的危害 ,并据此核算了典型滑动面的稳定性 ,本文将着重介绍对预应力锚杆锚索的加速度测试分析研究。