Community question answering (cQA) has become an important issue due to the popularity of cQA archives on the web. This paper is concerned with the problem of question retrieval. Question retrieval in cQA archives aims to find the existing questions that are semantically equivalent or relevant to the queried questions. However, the lexical gap problem brings about new challenge for question retrieval in cQA. In this paper, we propose to learn continuous word embeddings with metadata of category information within cQA pages for question retrieval. To deal with the variable size of word embedding vectors, we employ the framework of fisher kernel to aggregated them into the fixedlength vectors. Experimental results on large-scale real world cQA data set show that our approach can significantly outperform state-of-the-art translation models and topic-based models for question retrieval in cQA.

Based on observed temperature and velocity in 2005 in northwestern South China Sea, the shallow ocean responses to three tropical cyclones were examined. The oceanic response to Washi was similar to common observations with 2°C cooling of the ocean surface and slight warming of the thermocline resulted from vertical entrainment. Moreover, the wavefield was dominated by first mode near‐inertial oscillations, which were red‐shifted and trapped by negative background vorticity leading to an e‐folding timescale of 12 days. The repeated reflections by the surface and bottom boundaries were thought to yield the successive emergence of higher modes. The oceanic responses to Vicente appeared to be insignificant with cooling of the ocean surface by only 0.5°C and near‐inertial currents no larger than 0.10 m/s as a result of a deepened surface mixed layer. However, the oceanic responses to Typhoon Damrey were drastic with cooling of 4.5°C near the surface and successive barotropic‐like near‐inertial oscillations. During the forced stage, the upper ocean heat content decreased conspicuously by 11.65% and the stratification was thoroughly destroyed by vertical mixing. In the relaxation stage, the water particle had vertical displacement of 20–30 m generated by inertial pumping. The current response to Damrey was weaker than Washi due to the deepened mixed layer and the destroyed stratification. Our results suggested that the shallow water oceanic responses to tropical cyclones varied significantly with the intensity of tropical cyclones, and was affected by local stratification and background vorticity.

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In this contribution, we design a visual sensor for DNA hybridization with DNA probe-modified magnetic particles (MPs) and multiwalled carbon nanotubes (MWNTs) without involving a visual recognition element such as fluorescent/chemiluminescent reagents. It was found that DNA probe-modified MWNTs, which could be dispersed in aqueous medium and have strong light scattering signals under the excitation of a light beam in the UV-vis region, could connect with DNA probe-modified MPs together in the presence of perfectly complementary target DNA and form a sandwich structure. In a magnetic field, the formed MP-MWNT species can easily be removed from the solution, resulting in a decrease of light scattering signals. Thus, a magnetic particle-based sandwich sensor could be developed to detect DNA hybridization by measuring the light scattering signals with DNA-modified MWNTs as recognition elements. Experiments showed that the DNA-modified MPs sensor could be reused at least 17 times and was stable for more than 6 months.

H + was implanted into single-crystal silicon with a dose of 1×1016/cm2 and an energy of 30 KeV, and then He+ was implanted into the same sample with the same dose and an energy of 33 KeV. Both of the implantations were performed at room temperature. Subsequently, the samples were annealed in a temperature range from 200 to 450 °C for 1 h. Cross-sectional transmission electron microscopy, Rutherford backscattering spectrometry/channeling, elastic recoil detection, and high resolution x-ray diffraction were employed to characterize the strain, defects, and the distribution of H and He in the samples. The results showed that co-implantation of H and He decreases the total implantation dose, with which the surface could exfoliate during annealing. During annealing, the distribution of hydrogen did not change, but helium moved deeper and its distribution became sharper. At the same time, the maximum of the strain in the samples decreased a lot and also moved deeper. Furthermore, the defects introduced by ion implantation and annealing were characterized by slow positron annihilation spectroscopy, and two positron trap peaks were found. After annealing, the maximum of these two peaks decreased at the same time and their positions moved towards the surface. No bubbles or voids but cracks and platelets were observed by cross-sectional transmission electron microscopy. Finally, the relationship between the total implantation dose and the fraction of hydrogen in total implantation dose was calculated.

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