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双导堤工程下潮汐汊道与海岸潟湖地貌稳定性 被引量:1
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作者 匡翠萍 范家栋 +1 位作者 董智超 韩雪健 《同济大学学报(自然科学版)》 EI CAS CSCD 北大核心 2023年第10期1584-1594,共11页
以渤海湾沿岸具有双导堤工程的单一潮汐汊道的华北最大海岸潟湖—七里海潟湖为原型建立理想模型,通过设置包括临界侵蚀应力、临界淤积应力、泥沙沉速、初始床面高程和径流量等影响潟湖地貌演变的相关参数,得到理想模型达到稳定状态后的... 以渤海湾沿岸具有双导堤工程的单一潮汐汊道的华北最大海岸潟湖—七里海潟湖为原型建立理想模型,通过设置包括临界侵蚀应力、临界淤积应力、泥沙沉速、初始床面高程和径流量等影响潟湖地貌演变的相关参数,得到理想模型达到稳定状态后的纳潮量P和潮汐汊道断面最大流量Q_(m)。分别建立其与潮汐汊道断面面积A的相关关系式以表征潮汐汊道稳定性。比较分析发现在表征潮汐汊道稳定性方面,Q_(m)‒A关系较P‒A关系的拟合效果更佳。分别利用Q_(m)‒A关系以及泥沙净冲淤量计算得到潮汐汊道和潟湖稳定所需时长,对比结果表明潟湖明显滞后于潮汐汊道达到稳定状态,临界侵蚀应力对潮汐汊道稳定性影响更大,而临界淤积应力、泥沙沉速和初始床面高程对潟湖稳定性影响尤为显著,径流量对潟湖和潮汐汊道稳定性的影响相当。 展开更多
关键词 海岸潟湖 潮汐汊道 地貌稳定性 q_(m)-A关系 P-A关系 平衡状态
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Outstanding electromechanical performance in piezoelectric ceramics via synergistic effects of defect engineering and domain miniaturization
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作者 Zhifei Zhang Liang Chen +5 位作者 Huajie Luo Yueyun Zhang Yonghao Yao Guanfu Liu He Qi Jun Chen 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2023年第27期1-8,共8页
Piezoelectric ceramics with high mechanical quality factor Q_(m) and large piezoelectric coefficient d_(33) are urgently required for advanced piezoelectric applications.However,obtaining both of these prop-erties sim... Piezoelectric ceramics with high mechanical quality factor Q_(m) and large piezoelectric coefficient d_(33) are urgently required for advanced piezoelectric applications.However,obtaining both of these prop-erties simultaneously remains a difficult challenge due to their mutually restrictive relationship.Here 0.5Pb(Ni_(1/3)Nb_(2/3))O_(3)-0.5Pb(Zr_(0.3)Ti_(0.7))O_(3) piezoceramic with tetragonal(T)-rich MPB is designed as a matrix to construct the defect engineering by doping low-valent Mn ions.The strong coupling of defect dipole and T-rich phase can effectively hinder the rotation of P_(s),restrict domain wall motion and improve Q_(m).At the same time,the substituted Mn ions will introduce local random field,destroying the long-range or-dering of ferroelectric domain and reducing domain size.The miniaturized domain structure can increase poling efficiency and inhibit the reduction of d_(33).Guided by this strategy,Q_(m) has increased by more than 10 times and d_(33) has only decreased by about 25%.The optimized electromechanical performance with Q_(m)=822,d_(33)=502 pC/N,k_(p)=0.55 and tanδ=0.0069 can be obtained in the present study. 展开更多
关键词 PNN-PZT ceramics Defect engineering Domain miniaturization High mechanical quality factor q_(m) Large piezoelectric coefficient d_(33)
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