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Synthesis and characterization of novel Ti-containing mesoporous silicas support
Peihong Yao,Weiwei Hu,Yan Bao,Cuiling Zhang,Bochao Zhu,Wenxia Liu,Yongxiao Bai 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.3
Titanium-containing novel mesoporous silicas have been synthesized at ambient temperature by a sol-gel method using amines with alkyl chains of 10-16 carbon atoms as a templating surfactant. An identical synthesis procedure was followed together with the addition of different amounts of titanium (IV) source in the synthesis gels to obtain its titanium-containing silicate gels. Following this synthesis route, it was possible to prepare materials without forming extrawall TiO2. The transparent gel formed as a precursor resulted in a relatively high titanium incorporation in the silicate framework of up to 0.4% Ti. The characterization results show that most Ti4+ are isolated and tetrahedrally incorporated into the framework of the silicate gel. Raman spectra and UV-vis spectra indicated that most Ti atoms were incorporated as isolated Ti sites into the silicate framework, and materials with a higher wt% Ti using relatively more coordination agent to prevent TiO2 forming anatase.
Tissue-Specific CRISPR/Cas9 System of Cotton Pollen with GhPLIMP2b and GhMYB24 Promoters
Lei Jianfeng,Dai Peihong,Li Jiyang,Yang Mi,Li Xiuqin,Zhang Wanqi,Zhou Guantong,WangzhenGuo,Liu Xiaodong 한국식물학회 2021 Journal of Plant Biology Vol.64 No.1
CRISPR/Cas9 technology is a powerful tool for improving crop genetic traits. However, CRISPR/Cas9 system for efficient expression of cotton germ cells has still not been established. In this study, we developed a tissue-specific vectors to drive Cas9 expression with GhPLIMP2b and GhMYB24 promoters and established the effective method to transform cotton pollen by Agrobacterium vacuum infiltration. GhPLIMP2b and GhMYB24 promoters of cotton pollen were cloned into Cas9 expression vectors. The sgRNAs targetting to CLA1, ERA1 and GGB (drought-resistant negative regulation genes) were designed and constructed into GhPLIMP2b and GhMYB24 promoter vectors. Cotton pollens were tranformed by Agrobacterium vacuum infiltration with GhPLIMP2b and GhMYB24 promoter vectors. The results of clone sequencing shown that mutation types of the sequence were mainly base substitutions wth the frequency from 3.29 to 6.45%. Eleven potential off-target sites were chosen and two sites were observed. Our results indicated that GhPLIM2bP::Cas9 and GhMYB24P::Cas9 editing vectors achieved targeted edition of endogenous genes in cotton pollen, but there were a few off-target effects. This study provides an effective gene-editing system for the rapid acquisition of cotton mutants using pollen as a transgenic receptor.
Zhongfei Liu,Jiangtao Yuan,HUI ZHANG,Kuangwei Xiong,Shaowei Jin,Peihong Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.1
In this paper, the MOFs-derived carbonaceous ZnO and RGO (carbonaceous ZnO/RGO) composites have been prepared by the wet chemical method and carbonization process. The as-prepared products are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), Raman spectra, thermogravimetric (TG) analysis and X-ray photoelectron spectroscopy (XPS). The electromagnetic parameters of carbonaceous ZnO/RGO composites are investigated by the vector network analyzer. The results exhibit carbonaceous ZnO/RGO composites have a maximum absorption of - 37.12 dB at 6 GHz with thickness of 3.5 mm and the effective absorption (below -10 dB) bandwidth is up to 1.92 GHz (from 5.28 to 7.2 GHz). Thus, the carbonaceous ZnO/RGO composites have great potential in the field of electromagnetic wave absorption.
Yao Li,Haiqing Si,Yitong Zong,Xiaojun Wu,Peihong Zhang,Hongyin Jia,Shuqing Xu,Dayong Tang 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.6
The process of obtaining flight data from flight test is complex and costly, which makes it difficult to identify aerodynamic parameters. Therefore, Cessna172 flight simulator was used for flight data extraction, which ensures the convenience, efficiency and economy of the test. To obtain aerodynamic model, based on the idea of machine learning, a recurrent neural network was used to process multi-dimensional nonlinear flight test data, and a real-time recursive learning algorithm was proved to be suitable for dynamic training. Due to the large amount of state parameter data generated by aircraft, which will cause the real-time recursive learning algorithm to train slowly. So, Kalman filter algorithm was introduced for system identification. Considering validity analysis, the comparative verification method was used to verify system identification model. Results show that the aircraft aerodynamic and aerodynamic moment models have good applicability and can be popularized and applied.