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991.
侧重从材美、工巧和审美三个方面来论述木制器物文化,及其形成的“木道” 审美情趣,从而进一步论述了“以人为本,物我融一”的设计理念。 相似文献
992.
以三级式电力电子变压器的输入端级联H桥整流器为研究对象,针对系统运行的稳定性,借鉴双环控制思想,提出CHB整流器的双环控制方法。同时,针对其无功损耗、能量传输效率问题,提出一种基于虚拟相引入的共同占空比控制策略。在Matlab/Simulink平台搭建仿真模型,对所提出的CHB整流器的双环控制方法和基于虚拟相引入的共同占空比控制策略,与传统的控制策略进行对比分析,结果表明,所提策略可以有效减少谐波含量、降低无功损耗,提高系统运行的稳定性,改善系统的动态性能。 相似文献
993.
994.
固体氧化物燃料电池(SOFC)作为第三代燃料电池,以其能量转换效率高、燃料适用范围广、对环境友好、全固态等诸多优势而备受关注.双极板(又称连接体)作为固体氧化物燃料电池的重要组成部分之一,在SOFC电池堆中起到串并联单体电池并隔绝燃料气体与空气的作用,对电池性能及商用成本有很大影响.不同材料的双极板存在不同的性能问题,主要都集中在导电性能、抗氧化性能、化学稳定性及热膨胀系数是否匹配等方面.本文综述了传统陶瓷材料、合金材料、新型陶瓷材料、复合材料双极板的发展历程及最新研究进展,并着重介绍了组分优化设计及表面改性(涂覆活性氧化物涂层、稀土钙钛矿涂层及尖晶石涂层等)两种方式对于合金材料抑制镉元素向外扩散的能力、抗氧化性及导电性的改善.综合分析表明,通过组分优化设计和表面改性弥补合金作为双极板材料的性能缺陷,尝试制备新型陶瓷材料或复合材料等途径,有望获得高性能、低成本的双极板材料,从而实现SOFC的大规模商业化应用. 相似文献
995.
We demonstrate the technique of subsequent multitrack nonlinear imaging based on backscattered second-harmonic generation (B-SHG) and two-photon autofluorescence (TPA) to obtain large-area, high-contrast, submicron-resolution image ex vivo of esophageal stroma. Our findings show that this technique is effective in improving the B-SHG/TPA image contrast. It was found that the method can quantitatively obtain microscopic structural and biochemical information on stroma. Our work suggests that the technique has the potential to provide accurate and comprehensive information in determining the physiological and pathological states of the esophagus. 相似文献
996.
ompCwnToPOlogicreconstructionofnetworkisreferredtoaschangingconfigUrahonofnetworkbyswitchinginelectricpowersystemstoimprovetheoPerahngcondihonofsuchasPectSassecurity,qUalityoroPhhazation.TherationalconfigUrationofanelectricpowersystem..isessentialforitSstable.p..ti..['].ButtLheoperatingconditionsofpowersystemsareintricateandvolatile,soitisnotsuitabletooPerateapowrsystemwithafixedcon-figUrationfordifferentoperatingtrendsandoPeratingcon-ditions.CorrectSswitchingofnetworktofitthechangeinoP… 相似文献
997.
Zakhar R. Kudrynskyi Xueting Wang Jake Sutcliffe Mahabub A. Bhuiyan Yuhao Fu Zhuo Yang Oleg Makarovsky Laurence Eaves Andrij Solomon Volodymyr T. Maslyuk Zakhar D. Kovalyuk Lijun Zhang Amalia Patan 《Advanced functional materials》2020,30(9)
The design of advanced functional materials with customized properties often requires the use of an alloy. This approach has been used for decades, but only recently to create van der Waals (vdW) alloys for applications in electronics, optoelectronics, and thermoelectrics. A route to engineering their physical properties is by mixing isoelectronic elements, as done for the SnSe2(1?x)S2x alloy. Here, by experiment and first‐principles modeling, it is shown that the value of x can be adjusted over a wide range, indicating good miscibility of the SnS2 and SnSe2 compounds. The x‐dependence of the indirect bandgap energy from Eind = 1.20 eV for SnSe2 to Eind = 2.14 eV for SnS2, corresponds to a large bowing coefficient b ≈ 1 eV, arising from volume deformation and charge exchange effects due to the different sizes and orbital energies of the S‐ and Se‐atoms. This also causes composition‐dependent phonon energy modes, electron–phonon interaction, and temperature dependence of Eind. The alloys are exfoliable into thin layers with properties that depend on the composition, but only weakly on the layer thickness. This work shows that the electronic and vibrational properties of the SnSe2(1?x)S2x alloy and its thin layers provide a versatile platform for development and exploitation. 相似文献
998.
Lida Shen Wei Zhuo Mingbo Qiu Wei Jiang Kailin Zhao Chuan Wang 《Materials Science & Technology》2018,34(4):419-428
To improve the deposition rate and quality of nanocrystalline nickel coatings, a method involving movable, flexible friction, jet electrodeposition (MFFJE) was proposed in this paper. The effects of cathode scanning speed and current density on electrodeposited nickel coatings prepared by MFFJE were investigated. Compared with traditional jet electrodeposition, the results showed that MFFJE exerted remarkable effects, improving the deposition rate and quality of nickel coatings, and, when the cathode scanning speed was 1000?mm?min?1, the coating surface morphology was best. The maximum processing current density of nickel plating was more than 250?A?dm?2. The grain size was decreased to 11.7?nm, hardness increased to 546?HV, and coating corrosion resistance significantly improved. 相似文献
999.
Haonan Si Zheng Zhang Qingliang Liao Guangjie Zhang Yang Ou Suicai Zhang Hualin Wu Jing Wu Zhuo Kang Yue Zhang 《Advanced materials (Deerfield Beach, Fla.)》2020,32(4):1904702
An in-depth understanding and effective suppression of nonradiative recombination pathways in perovskites are crucial to their crystallization process, in which supersaturation discrepancies at different time scales between CH3NH3I (MAI, methylammonium iodide) and PbI2 remain a key issue. Here, an A-site management strategy via the introduction of an A-site placeholder cation, NH4+, to offset the deficient MA+ precipitation by occupying the cavity of Pb–I framework, is proposed. The temporarily remaining NH4+ is substituted by subsequently precipitated MA+. The temperature-dependent crystallization process with the generation and consumption of a transient phase is sufficiently demonstrated by the dynamic changes in crystal structure characteristic peaks through in situ grazing-incidence X-ray diffraction and the surface potential difference evolution through temperature-dependent Kelvin probe force microscopy. A highly crystalline perovskite is consequently acquired, indicated by the enlarged grain size, lowered nonradiative defect density, prolonged carrier lifetime, and fluorescence lifetime imaging. Most importantly, it is identified that the A-site IMA defect is responsible for such crystal quality optimization based on theoretical calculations, transient absorption, and deep-level transient spectroscopy. Furthermore, the universality of the proposed A-site management strategy is demonstrated with other mixed-cation perovskite systems, indicating that this methodology successfully provides guidance for synthesis route design of highly crystalline perovskites. 相似文献
1000.
Chen Shaoyun Chen Miaomiao Huang Huiling Liu Xiaoying Qu Bo Wang Rui Liu Kewei Zheng Yanyu Zhuo Dongxian 《Applied Composite Materials》2022,29(4):1597-1619
Applied Composite Materials - The increased demand for durable yet flexible and stretchable membranes has inspired the investigation of polymer nanocomposite films, such as those based on polyvinyl... 相似文献