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71.
72.
Jiwei Yao Xuyan Zong Chun Cui Lixia Mu Haifeng Zhao 《International Journal of Food Science & Technology》2018,53(7):1698-1704
Three kinds of beers with different degrees of ageing were used to examine their nonvolatile small molecules by a metabonomics approach based on ultra performance liquid chromatography coupled with quadrupole time‐of‐flight tandem mass spectrometry (UPLC‐Q‐ToF‐MS/MS). Results showed that a total of 2114 compounds were detected in forced‐aged beers with the positive mode of UPLC‐Q‐ToF‐MS/MS. There was a clear separation among three groups of beers with different degrees of ageing in principal component analysis (PCA) model. Sixteen potential metabolite markers related to beer oxidative stability were identified by orthogonal partial least‐squares discriminate analysis (OPLS‐DA). Results from the changes in the spectrum also indicated that some new compounds formed in beer during forced ageing. Thus, the proposed metabonomics approach is a powerful tool to give a fully understanding the ageing process of beer based on the identification of the markers related to oxidative stability. 相似文献
73.
正位于河南省西北部的焦作市,北依太行,南临黄河。长期以来,煤炭产业为焦作带来了持续的经济增长和长久的社会繁荣。然而,经过不断地开采,焦作的煤炭资源几近枯竭,环境也遭受了极大的污染。曾经辉煌的大小煤窑和矿山,成为焦作土地上难以愈合的疤痕。转型,成为焦作城市形象更新的重要课题。2017年9月,第十一届中国国际园林博览会在郑州召开。焦作作 相似文献
74.
基于微电子机械系统(MEMS)工艺设计并制作了一种THz垂直转接结构,该结构采用6层硅片堆叠的硅微波导形式。理论分析计算了垂直转接结构的参数,并使用三维电磁场分析软件HFSS对该结构进行了模拟仿真。设计得到了中心频率为365 GHz、带宽为80 GHz、芯片尺寸为10 mm×7 mm×2.7 mm的THz垂直转接结构。给出了一套基于MEMS工艺的硅微波导的制作流程,制作了365 GHz垂直转接结构并对其进行测试。获得的THz垂直转接结构的回波损耗随频率变化的测试结果与仿真结果基本一致。采用MEMS工艺制作的硅微波导垂直转接结构具有精度高、一致性好、成本低的特点,满足THz器件的发展需求。 相似文献
75.
Sijie Cai Bin Yao Wei Feng Zhiqin Cai Binqiang Chen Ze He 《The International Journal of Advanced Manufacturing Technology》2020,106(7):2779-2791
Milling process simulations provide a useful way to design and adjust the technical parameters of milling process. As the milling process involves coupling 相似文献
76.
Inconel 718 thin walls were fabricated via electron beam directed energy deposition (EB-EDE) to investigated their microstructure and mechanical properties in terms of the deposition modes. Results revealed that the deposition modes had great effects on the microstructural evolution and thus influenced the mechanical properties. The layered nature and the fine dendrites were produced by the intermittent deposition, while the coarse and irregular cellular crystals were formed under the continuous deposition. The harmful Laves phase was precipitated under both deposition modes. The microhardness and tensile strength of the build-ups deposited intermittently were higher because there were fewer Laves phase. This work provided a new perspective to explain the microstructure differences of multi-layered components formed by EB-DED. 相似文献
77.
Duan Haiyang Wang Xudong Bai Yu Yao Man Guo Qingtao 《The International Journal of Advanced Manufacturing Technology》2020,106(11):4777-4787
The International Journal of Advanced Manufacturing Technology - Breakout is the most serious incident in continuous casting. The missing and false alarms will seriously damage the caster and... 相似文献
78.
79.
Bilal Shahid Dangqiang Zhu Qian Wang Xiyue Yuan Irfan Ismail Yao Wu Zurong Du Renqiang Yang 《Polymer International》2020,69(6):564-570
To optimize the energy levels of the structural framework of isoindigo polymers, a series of asymmetric isoindigo based low bandgap polymers with chlorine, fluorine and thiazole substituents was constructed and their optical, electrochemical and photovoltaic properties were comparatively evaluated for the impact of different substitutions. In comparison with the polymer based on 2,2'‐bithiophene and isoindigo unit (PTi) with non‐substituted bithiophene as the donor moiety, the highest occupied molecular orbital energy level for the newly synthesized polymers is significantly decreased, and in turn an improvement of the open‐circuit voltage (VOC) is noted in the corresponding photovoltaic devices. More importantly, combined with a low bandgap of 1.32 eV, the energy losses (Eloss) could be reduced to 0.61 eV for polymer based on chlorinated 2,2'‐bithiophene and isoindigo unit (PCl). In addition, the halogen moieties are observed to be superior in device fabrication and give better values than the thiazole substituent. Both fluorinated and chlorinated polymer donors exhibited improved performance compared with the original polymer PTi. Consequently, this work not only presents the influence of different electron withdrawing substituents on the physicochemical and photovoltaic performance, but also backs the concept of how to reduce the energy loss via the heteroatom effect. © 2020 Society of Chemical Industry 相似文献
80.
Feiyue Yang Yiwen Yao Zichun Yang Shuang Zhao Guobing Chen Kunfeng Li 《Ceramics International》2021,47(13):18351-18357
To meet demand for lightweight and high-strength ceramic foams, in-situ self-reinforced Si3N4 ceramic foams, with compressive strength of 13.2–45.9 MPa, were fabricated by protein foaming method combined with sintered reaction-bonded method. For comparison, ordinary protein foamed ceramics with irregular block microstructure were fabricated via reaction-bonded method, which had compressive strength of 3.6–20.5 MPa. Physical properties of these two types of samples were systematically compared. When open porosity was about 80%, both types of Si3N4 ceramic foams had excellent thermal insulation properties (<0.15 W m?1 K?1), while compressive strength of in-situ self-reinforced samples increased by more than 158% compared with ordinary samples. Under high-temperature oxidation conditions, microstructures of both types of samples were deformed with increase in oxidation temperature. Moreover, after oxidation temperature was increased to 1400 °C, oxidation weight gain decreased from 18.07% for ordinary samples to only 2.18% for self-reinforced samples. Thus, high-temperature oxidation resistance of Si3N4 ceramic foams was greatly improved. 相似文献