http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Flexural performance test of a prestressed concrete beam with plastic bellows
Xuansheng Cheng,Junliang Hong,Liang Ma,Guoliang Li 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.2
The flexural performance of 8 types of prestressed concrete beams with plastic bellows under different grouting compactness is examined in this paper. By applying concentrated load and symmetrical load to 8 types of prestressed concrete test beams with plastic bellows, the flexural performance test of each test beam is carried out, and the mechanical characteristics and failure morphology of each test beam under different grouting compactness are discussed. The influence of duct grouting compactness on the strain of steel bars and concrete, mid-span deflection and stiffness of prestressed concrete beam are analyzed. The results show that the cracking load and ultimate load of the test beam increases constantly with the increase of the duct grouting compactness, and the flexural bearing capacity of prestressed concrete beams has also been significantly improved. After the concrete is cracked, the mid-span deflection of the prestressed concrete beam gradually decreases with the increase of the duct grouting compactness under the same load form and load grade. At the same load grade, the mid-span deflection change of prestressed concrete beams under concentrated load is much larger than that under symmetric load. The ductility coefficient of prestressed concrete beams with plastic bellows decreases as the grouting compactness increases. In engineering practice, the quality of duct grouting compactness about the prestressed concrete beam should be strictly controlled and improved.
Lin, Jia,Chen, Hong,Gao, Yang,Cai, Yao,Jin, Jianbo,Etman, Ahmed S.,Kang, Joohoon,Lei, Teng,Lin, Zhenni,Folgueras, Maria C.,Quan, Li Na,Kong, Qiao,Sherburne, Matthew,Asta, Mark,Sun, Junliang,Toney, Mic National Academy of Sciences 2019 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.116 No.47
<P><B>Significance</B></P><P>Metal halide perovskites attract great interest for a wide range of applications due to their remarkable optoelectronic properties. The development of environmentally friendly halide perovskite materials with various crystal structures and compositions offers unprecedented opportunities to achieve desired properties and applications. In this work, we demonstrated an In-based, charge-ordered all-inorganic halide double perovskite with the composition of Cs<SUB>2</SUB>In(I)In(III)Cl<SUB>6</SUB> synthesized by solid-state reaction. High-pressure optical properties were studied, and a pressure-driven, fully reversible semiconductor–metal phase transition was discovered. This In-based charge-ordered structure may inspire new understanding of halide perovskite as well as provide a platform for future discovery of exotic electronic phenomena such as high-<I>T</I><SUB>C</SUB> superconductivity in halide perovskite compounds.</P><P>Phase transitions in halide perovskites triggered by external stimuli generate significantly different material properties, providing a great opportunity for broad applications. Here, we demonstrate an In-based, charge-ordered (In<SUP>+</SUP>/In<SUP>3+</SUP>) inorganic halide perovskite with the composition of Cs<SUB>2</SUB>In(I)In(III)Cl<SUB>6</SUB> in which a pressure-driven semiconductor-to-metal phase transition exists. The single crystals, synthesized via a solid-state reaction method, crystallize in a distorted perovskite structure with space group <I>I</I>4/<I>m</I> with <I>a</I> = 17.2604(12) Å, <I>c</I> = 11.0113(16) Å if both the strong reflections and superstructures are considered. The supercell was further confirmed by rotation electron diffraction measurement. The pressure-induced semiconductor-to-metal phase transition was demonstrated by high-pressure Raman and absorbance spectroscopies and was consistent with theoretical modeling. This type of charge-ordered inorganic halide perovskite with a pressure-induced semiconductor-to-metal phase transition may inspire a range of potential applications.</P>