Considering the importance of user-innovation knowledge to product and service innovation, this paper proposed knowledge discovering and analyzing methods on user-innovation communities based on weighted knowledge network (WKN). First, web mining methods were used for getting forum posts in virtual user-innovation communities, then the acquired keywords and the statistical data were processed and integrated into a WKN model. Next, based on the WKN model, the paper proposed new methods to discover the core innovation knowledge, the developing innovation knowledge and the potential innovation knowledge through analyzing the structure of WKN model, including weights of nodes and edges, cliques, the strong or weak ties, etc. Finally, Xiaomi community was taken as the study case to verify the validity of the methods. Compared with the existing method of user knowledge discovery, the presented methods are more quantitatively, conveniently and visually and provide new tools to study and utilize the user-innovation knowledge in enterprise virtual communities.

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The silica gel drying method was utilized to reduce the moisture content of Elymus dahuricus seeds from an original content of 9.03 to 7.69, 6.10, 4.97, 4.47, 3.83, 2.58 and 1.26%. After sealing the seeds in aluminum foil bags, they were placed at-4°C, 4°C, room temperature and 45°C to store for 12 months and to identify their physiological and biochemical indicators. Results indicate that ultra-dry storage can: 1) Improve the storability and membrane permeability of E. dahuricus seeds, 2) increase the activity of E. dahuricus SOD, POD and CAT, and 3) lower MDA content. Moderate ultra-dry storage at room temperature can reach the conserved effect of low-temperature without intense ultra-drying. Therefore, the moderate ultra-dry can be use as effective measure for the conservation of E. dahuricus germplasm resources.

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Self-heating effect has been the limited factors for the performance improvement of GaN electronics. Directly growth of polycrystalline diamond on GaN material to solve the heating problem of GaN devices becomes one of the resraech highlights. Polycrystalline diamond on Si-based GaN material has the advantages of being close to the channel region and having high heat dissipation efficiency. But there is a problem that the thermal expansion mismatch between polycrystalline diamond and GaN material leads to the electrical characteristics deterioration of GaN. In this work, we adopted microwave plasma chemical vapor deposition (MPCVD) method to grow polycrystalline diamond on 2-inch Si-based GaN material. The test results showed that polycrystalline diamond was uniform as a whole. The average thicknesses are 9~81 μm. With the thickness increase of polycrystalline diamond, the XRD (002) diffraction peak FWHM increment and mobility loss gradually increased for the Si-based GaN material. Through laser cutting and acid etching, the Si-based GaN material was successfully peeled off from the polycrystalline diamond. It was found that during the high temperature growth of diamond, hydrogen atoms had an etching effect on the defect positions of the silicon nitride epitaxial layer to form a hole region in the GaN, and the etching depth can reach the intrinsic GaN layer. During the cooling process, a crack region formed around the hole region. The Raman characteristic peaks, XRD (002) diffraction peaks FWHM, and electrical properties of the exfoliated Si-based GaN materials all returned to their intrinsic states. The above results indicated that the thermal expansion mismatch between polycrystalline diamond and Si-based GaN introduced stress to GaN, which caused the GaN lattice distortion, and leading to electrical property degradation of GaN material. The degradation of GaN material was recoverable rather than destructive.