|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Enhanced piezoelectricity in Na and Ce co-doped CaBi_(4)Ti_(4)O_(15) ceramics for high-temperature applications显示文摘The sodium(Na)and Ce co-doped calcium bismuth titanate(CBT;CaBi_(4)Ti_(4)O_(15))Aurivillius ceramics in a Ca_(1-x)(Na_(0.5)Ce_(0.5)),Bi_(4)Ti_(4)O_(15)(CNCBT;doping content(x)=0,0.03,0.05,0.08 and 0.12)system were synthesized by the conventional solid-state sintering method.All compositions show a single-phase orthorhombic(space group:A2jam)structure at room temperature.The shift of the Curie point(T_(c))towards lower temperatures(T)on doping results from the increased tolerance factor(t).The substitution-enhanced ferroelectric performance with large maximum polarization(P_(m))and facilitated domain switching is evidenced by the developed electrical polarization-electric field(P-E)and electrical current-electric field(I-E)hysteresis loops.The piezoelectric coefficient(d_(33)=20.5±0.1 pC/N)of the x=0.12 sample is about four times larger than that of pure CBT.The improved piezoelectric properties can be attributed to the high remanent polarization(P_(r))and relatively high dielectric permittivity(ε′).In addition,multi-sized(micron and sub-micron)domain structures were observed in the CNCBT ceramics by the piezoresponse force microscope(PFM).The multiple-sized ferroelectric domain structure with smaller domains is beneficial to the easy domain switching,enhanced ferroelectric performance,and improved piezoelectric properties of the CNCBT ceramics.The designed Aurivillius-phase ferroelectric ceramics with the T_(c) around 765℃and high piezoelectric coefficient(d_(33))are suitable for high-temperature piezoelectric applications. | Zimeng Hu Vladimir Koval Hangfeng Zhang Kan Chen Yajun Yue Dou Zhang Haixue Yan | 2023 | Journal of Advanced Ceramics2023，12，7： | 1 |
| 2 | Microscopic pore-fracture configuration and gas-filled mechanism of shale reservoirs in the western Chongqing area,Sichuan Basin,China显示文摘Taking the Upper Ordovician Wufeng Formation to Lower Silurian Longmaxi Formation shale reservoirs in western Chongqing area as the study target,the argon ion polishing scanning electron microscope and nuclear magnetic resonance(NMR)experiments of different saturated wetting media were carried out.Based on the image processing technology and the results of gas desorption,the pore-fracture configuration of the shale reservoirs and its influence on gas-filled mechanism were analyzed.(1)The reservoir space includes organic pores,inorganic pores and micro-fractures and there are obvious differences between wells in the development characteristics of micro-fractures;the organic pores adjacent to the micro-fractures are poorly developed,while the inorganic pores are well preserved.(2)According to the type,development degree and contact relationship of organic pore and micro-fracture,the pore-fracture configuration of the shale reservoir is divided into four types.(3)Based on the differences in NMR T_(2) spectra of shale samples saturated with oil and water,an evaluation parameter of pore-fracture configuration was constructed and calculated.The smaller the parameter,the better the pore-fracture configuration is.(4)The shale reservoir with good pore-fracture configuration has well-developed organic pores,high porosity,high permeability and high gas content,while the shale reservoir with poor pore-fracture configuration has micro-fractures developed,which improves the natural gas conductivity and leads to low porosity and gas content of the reservoir.(5)Based on pore-fracture configuration,from the perspective of organic matter generating hydrocarbon,micro-fracture providing migration channel,three types of micro gas-filled models of shale gas were established. | FU Yonghong JIANG Yuqiang DONG Dazhong HU Qinhong LEI Zhi'an PENG Hao GU Yifan MA Shaoguang WANG Zimeng YIN Xingping WANG Zhanlei | 2021 | Petroleum Exploration and Development2021，48，5： | 0 |
| 3 | Time-restricted feeding downregulates cholesterol biosynthesis program via RORγ-mediated chromatin modification in porcine liver organoids显示文摘Background: Time-restricted feeding(TRF) is a dieting strategy based on nutrients availability and diurnal rhythm,shown to improve lipid metabolism efficiency. We have demonstrated previously that retinoic acid-related(RAR)orphan receptor(ROR) γ is the primary transcription factor controlling cholesterol(CHO) biosynthesis program of animals. However, the functional role of RORγ in liver physiology of pigs in response to TRF has not been determined, largely due to the lack of functional models and molecular tools. In the present study, we established porcine liver organoids and subjected them to restricted nutrients supply for 10-h during the light portion of the day.Results: Our results showed that TRF regimen did not alter hepatocyte physiology, including unchanged cell viability, caspase 3/7 enzyme activity and the gene signature of cell proliferation in porcine liver organoids,compared to the control group(P > 0.05). Furthermore, we found that TRF downregulated the hepatic CHO biosynthesis program at both mRNA and protein levels, along with the reduced cellular CHO content in porcine liver organoids(P < 0.05). Using unbiased bioinformatic analysis of a previous ChIP-seq data and ChIP-qPCR validation, we revealed RORγ as the predominant transcription factor that responded to TRF, amongst the 12 targeted nuclear receptors(NRs)(P < 0.05). This was likely through RORγ direct binding to the MVK gene(encoding mevalonate kinase). Finally, we showed that RORγ agonists and overexpression enhanced the enrichment of cofactor p300, histone marks H3 K27 ac and H3K4me1/2, as well as RNA polymerase II(Pol-II) at the locus of MVK, in TRF-porcine liver organoids, compared to TRF-vector control(P < 0.05).Conclusions: Our findings demonstrate that TRF triggers the RORγ-mediated chromatin remodeling at the locus of CHO biosynthesis genes in porcine liver organoids and further improves lipid metabolism. | Kexin Zhang Hao Li Zimeng Xin Yanwei Li Xiaolong Wang Yun Hu Haoyu Liu Demin Cai | 2021 | Journal of Animal Science and Biotechnology2021，12，1： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员