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In order to formulate a nitrogen (N) management strategy under continuous full amount of straw returning (CFSR) for double cropping rice production, long-term (2013–2016) paddy field experi...

In modern academic social network, it is very difficult for scholars to find academic papers consistent with their research direction. Time is a critical factor in paper recommendation. As time goes on, the impact of an academic paper would gradually fade. Likewise, the research interests of users may also change. Therefore, we propose a temporal perceptual neural collaborative filtering model that integrates the multi-dimensional features of papers. We conducted our experiments on the dataset from CiteULike, comparing the recommended results by using four time-decay functions and evaluating our model with multiple evaluation indicators. The satisfactory results show that our model is effective in filtering out the expired papers by considering the characteristics of papers and the changes of scholars' interests.

This research investigated the effects of ciprofloxacin (CIP) (0.5, 5, and 20 mg/L) on SBR systems under different carbon source conditions. Microbial community abundance and structure were determined by quantitative PCR and high-throughput sequencing, respectively. The biodegradation production of CIP and possible degradation mechanism were also studied. Results showed that CIP had adverse effects on the nutrient removal from wastewater. Compared with sodium acetate, glucose could be more effectively used by microorganisms, thus eliminating the negative effects of CIP. Glucose stimulated the microbial abundance and increased the removal rate of CIP by 18%–24%. The mechanism research indicated that Proteobacteria and Acidobacteria had a high tolerance for CIP. With sodium acetate as a carbon source, the abundance of nitrite-oxidizing bacterial communities decreased under CIP, resulting in the accumulation of nitrite and nitrate. Rhodanobacter and Microbacterium played a major role in nitrification and denitrification when using sodium acetate and glucose as carbon sources. Dyella and Microbacterium played positive roles in the degradation process of CIP and eliminated the negative effect of CIP on SBR, which was consistent with the improved removal efficiency of pollutants.

RIG-I-MAVS antiviral signaling represents an important pathway to stimulate interferon production and confer innate immunity to the host. Upon binding to viral RNA and Riplet-mediated polyubiquitination, RIG-I promotes prion-like aggregation and activation of MAVS. MAVS subsequently induces interferon production by activating two signaling pathways mediated by TBK1-IRF3 and IKK-NF-κB respectively. However, the mechanism underlying the activation of MAVS downstream pathways remains elusive. Here, we demonstrated that activation of TBK1-IRF3 by MAVS-Region III depends on its multimerization state and identified TRAF3IP3 as a critical regulator for the downstream signaling. In response to virus infection, TRAF3IP3 is accumulated on mitochondria and thereby facilitates the recruitment of TRAF3 to MAVS for TBK1-IRF3 activation. Traf3ip3-deficient mice demonstrated a severely compromised potential to induce interferon production and were vulnerable to RNA virus infection. Our findings uncover that TRAF3IP3 is an important regulator for RIG-I-MAVS signaling, which bridges MAVS and TRAF3 for an effective antiviral innate immune response.

Al2O3 dispersion copper alloy powder was prepared by internal oxidation, and three consolidation methods—high-velocity compaction (HVC), hot pressing (HP), and hot extrusion (HE)—were used to prepare Al2O3 dispersion-strengthened copper (Cu–Al2O3) alloys. The microstructures and properties of these alloys were investigated and compared. The results show that the alloys prepared by the HP and HE methods exhibited the coarsest and finest grain sizes, respectively. The alloy prepared by the HVC method exhibited the lowest relative density (98.3% vs. 99.5% for HP and 100% for HE), which resulted in the lowest electrical conductivity (81% IACS vs. 86% IACS for HP and 87% IACS for HE). However, this alloy also exhibited the highest hardness (77 HRB vs. 69 HRB for HP and 70 HRB for HE), the highest compressive strength (443 MPa vs. 386 MPa for HP and 378 MPa for HE), and the best hardness retention among the investigated alloys. The results illustrate that the alloy prepared by the HVC method exhibits high softening temperature and good mechanical properties at high temperatures, which imply long service life when used as spot-welding electrodes.

High-velocity compaction (HVC) technology was applied to press titanium-based blended elemental powders containing boron sources of TiB2 and LaB6, and in-situ TiB whiskers reinforced titanium matrix composites (TMCs, TiB/Ti-4.5 Al-6.8 Mo-1.5 Fe) were successfully prepared after vacuum sintering at 1250 °C for 3 h. The effects of forming ability of the blended powders by HVC and TiB volume fraction (5–20%) on microstructure and mechanical properties of composites were studied. The results showed that the blended powders could be pressed by HVC into green compacts with relative density no less than 94%. While the hardness and brittleness of TMCs increased with increasing TiB content, the TMCs with 10% TiB had the maximum tensile strength of 1147 MPa due to the combined effects of a relatively high relative density, a sufficient reinforcement of TiB and a homogeneous microstructure for this composition. The properties of the matrix alloy were also studied.

High-velocity compaction (HVC) technology was adopted to press titanium-based powders produced by blended elemental powder process, and low-cost titanium alloy (Ti–4.5Al–6.8Mo–1.5Fe) was prepared through vacuum sintering at 1050, 1150 and 1250 °C, respectively. The forming ability of blended powders by HVC and properties of alloys prepared at different temperatures were investigated. The results showed that the blended powders could be well formed by HVC method, and the highest relative green density reached 96.20%. Dense alloys were easily obtained through sintering at 1050–1250 °C. The alloy sintered at 1150 °C exhibited the best comprehensive mechanical properties, with microhardness (HV2.0) of 374, flexural strength of 2364 MPa, tensile strength of 1129 MPa and elongation of 3.75%. The increment of oxygen content was only 0.10 wt.% after the whole process.

Three Ti-6Al-4V alloy powders with median diameters of 103, 66 and 44 μm, respectively, were pressed by high-velocity compaction (HVC) technology and then sintered in vacuum. The effects of particle sizes on forming as well as properties of sintered samples were investigated. The results show that fine powders are more difficult to press than coarse powders and its compact density is lower too. But the sintered density of fine powders is obviously higher than that of coarse powders. Compared with the powders with 103 and 66 μm in diameter, the green density with 44 μm diameter powders is lower, which is 85.1% of theoretical density (TD) at an impact energy of 913 J. After sintering at 1300 °C for 2.5 h, the sintered density of the compacts with 44 μm diameter powders is the highest, and reaches 98.2% of TD. Moreover, the sintered sample with 44 μm in diameter has the highest hardness and compressive strength, which are HV 354 and 1265 MPa, respectively.

In this paper, the theoretical model of powder canning extrusion with two steps of multiple compress and steady flow was built on certain conditions based on the porous plastic deformation theory which was given by OYANE. The theoretical analyse and mathematical deduce of the densification process of powder canning extrusion was carried on. The densification expression (dρ/ρ) and hydrostatic pressure (σm) in multiple compress and the extrusion force (p) in steady flow were studied. The results showed that, in step of multiple compress, the hydrostatic pressure and densification velocity increase with the increasing wall thickness of can. In step of steady flow, the extrusion force was not only affected by the yield stress of can material and porous body, but also affected by the relative density of porous body and wall thickness of can.

We discuss the wavelet transform profilometry based on the continuous wavelet transform technique as viewed from frequency analysis. We deduce the expression of one-dimensional (1-D) and two-dimensional (2-D) wavelet transform in frequency domain and analyze their characteristics in the application of demodulating the fringe patterns. We also compare 1-D CWT and 2-D CWT in demodulating the oblique fringe patterns with dual carrier frequency components. When oblique fringe patterns are processed, the direction normal to the grating line and x axis or y axis is not identical. By 1-D CWT, in which wavelet transform is carried out row by row, we cannot obtain the most similarity between local signal and the wavelet functions with different dilation values. While a fan 2-D continuous wavelet transformation can deal with the fringe pattern as a 2-D unit as well as has multi-directions, its advantage is that it can be used to exact the information in the spatial direction. However, its spatial localization ability is not very good, which leads that it is not suitable for demodulating the fringe patterns with high phase variation. Computer simulations and experiments have verified our analysis.

Pure titanium powder was pressed into two kinds of samples through high-velocity compaction technology. The first was rings with 60 mm outer and 30 mm inner diameters and a mass of 57 g, and the second was cylinders with 20 mm diameter and a mass of 10 g. For the rings, the maximum shapable relative density reached 76.2% at impact energy of 2283 J. For the cylinders, however, it reached 96.0% at much lower impact energy of 1217 J. The reasons for the contradictory effects were analyzed, and a new quantity, impact energy per unit mass, was put forth to well characterize the difference. In addition, the relations between peak pressure and green density of the two kinds of samples were found to comply with Huang Pei-yun equation, and the densification mechanism was discussed.

We discuss the structure condition and sampling condition of wavelet transform profilometry (WTP) based on dual-frequency fringe pattern in this work. In the mentioned method a grating fringe with dual-frequency components is projected onto an object. And two wavelet ridge lines can be extracted by means of wavelet analysis, from which we can calculate two groups of wrapped phase information. Afterwards the retrieved phase with higher precision can be obtained through phase unwrapping process. However, it should be noted that the spectral aliasing of the deformed fringe pattern must be avoided in order to restore the correct phase information. And the two fringe carrier frequencies have to obey some rules as well. In this paper, the structure condition and sampling condition of the proposed method is deduced from the point of view of frequency analysis. It is proven that there would be no frequency overlapping in the deformed fringe pattern only when both of the two conditions mentioned previously are fulfilled. The results of computer simulations and experiments verify the validity of our theory.

A new kind of machinable composite plate was developed for microwave antenna in this paper, in which ceramic powder of CaO-Li 2 O-Ln 2 O 3 -TiO 2 was mixed with PTFE polymer in different proportions. It was showed that the permittivity of the composite plate was enhanced from 4 to 15 with the increasing content of ceramic powder; meanwhile, the quality factor was maintained at 1000GHz. The antenna was obtained with the composite plate which was machined to suitable size and covered with copper electrodes. The antenna's bandwidth was about 60MHz and standing wave ratio was near 1.12.