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Boundary conditions for the bending of a piezoelectric beam

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science china(Physics,Mechanics & Astronomy) 2008年第7期51卷 847-856页

作者： gao yang1, xu sipeng2 & zhao baosheng3.1 college of science, china agricultural university, beijing 100083, china 2 college of Engineering, Ocean university of china, Qingdao 266071, china 3 School of Mechanical Engineering, university of science and Technology Liaoning, Anshan 114044, china college of science China Agricultural University Beijing China college of Engineering Ocean University of China Qingdao China School of Mechanical Engineering University of Science and Technology Liaoning Anshan China

For beam bending in transversely isotropic piezoelectric media, the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate stress and mixed boundary conditions accurate to all orders for the beam of general edge geometry and loadings. By generalizing the method developed by Gregory and Wan, a set of necessary conditions on the edge-data for the existence of a rapidly decaying solution is established. The prescribed edge-data of the beam must satisfy these conditions in order that they could generate a decaying state within the beam. When stress and mixed conditions are imposed on the beam edge, these decaying state conditions for the case of bending deformation of piezoelectric beam are derived explicitly. They are then used for the correct formulation of boundary conditions for the beam theory solution (or the interior solution). Besides, an analytical solution of elastic beam is formulated to verify validity of our boundary conditions. For the stress data, our boundary conditions coincide with those obtained in conventional forms of beam theories. More importantly, the appropriate boundary conditions with two sets of mixed edge-data are obtained for the first time.

关键词： boundary conditions beam bending piezoelectric media decaying states regular states

The refined theory of deep rectangular beams for symmetrical deformation

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science china(Physics,Mechanics & Astronomy) 2009年第6期52卷 919-925页

作者： gao yang1 & WANG MinZhong2 1 college of science, china agricultural university, beijing 100083, china 2 State Key Laboratory for Turbulence and Complex Systems and Department of Mechanics and Aerospace Engineering, Peking university, beijing 100871, china college of science China Agricultural University Beijing China State Key Laboratory for Turbulence and Complex Systems and Department of Mechanics and Aerospace Engineering Peking University Beijing China

Based on elasticity theory, various one-dimensional equations for symmetrical deformation have been deduced systematically and directly from the two-dimensional theory of deep rectangular beams by using the Papkovich-Neuber solution and the Lur'e method without ad hoc assumptions, and they construct the refined theory of beams for symmetrical deformation. It is shown that the displacements and stresses of the beam can be represented by the transverse normal strain and displacement of the mid-plane. In the case of homogeneous boundary conditions, the exact solutions for the beam are derived, and the exact equations consist of two governing differential equations: the second-order equation and the transcendental equation. In the case of non-homogeneous boundary conditions, the approximate governing differential equations and solutions for the beam under normal loadings only and shear loadings only are derived directly from the refined beam theory, respectively, and the correctness of the stress assumptions in classic extension or compression problems is revised. Meanwhile, as an example, explicit expressions of analytical solutions are obtained for beams subjected to an exponentially distributed load along the length of beams.

关键词： deep rectangular beams the refined theory symmetrical deformation the Papkovich-Neuber solution the Lur’e method

The refined theory of deep rectangular beams based on general solutions of elasticity

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science china(Physics,Mechanics & Astronomy) 2006年第3期49卷 291-303页

作者： gao yang1 & WANG Minzhong2 1. college of science, china agricultural university, beijing 100083, china 2. State Key Laboratory for Turbulence and Complex Systems and Department of Mechanics and Engi- neering science, Peking university, beijing 100871, china college of science China Agricultural University Beijing China State Key Laboratory for Turbulence and Complex Systems and Department of Mechanics and Engineering science Peking University Beijing China

The problem of deducing one-dimensional theory from two-dimensional the- ory for a homogeneous isotropic beam is investigated. Based on elasticity theory, the re- fined theory of rectangular beams is derived by using Papkovich-Neuber solution and Lur’e method without ad hoc assumptions. It is shown that the displacements and stresses of the beam can be represented by the angle of rotation and the deflection of the neutral surface. Based on the refined beam theory, the exact equations for the beam without transverse surface loadings are derived and consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beam under transverse loadings are derived directly from the refined beam theory and are almost the same as the governing equations of Timoshenko beam theory. In two ex- amples, it is shown that the new theory provides better results than Levinson’s beam the- ory when compared with those obtained from the linear theory of elasticity.

关键词： deep rectangular beams,the refined theory,Papkovich-Neuber solution,Lur'e method,governing equation

The refined theory of transversely isotropic piezoelectric rectangular beams

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science china(Physics,Mechanics & Astronomy) 2006年第4期49卷 473-486页

The problem of deducing one-dimensional theory from two-dimensional theory for a transversely isotropic piezoelectric rectangular beam is investigated. Based on the piezoelasticity theory, the refined theory of piezoelectric beams is derived by using the general solution of transversely isotropic piezoelasticity and Lur'e method without ad hoc assumptions. Based on the refined theory of piezoelectric beams, the exact equations for the beams without transverse surface loadings are derived, which consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beams under transverse loadings are derived directly from the refined beam theory. As a special case, the governing differential equations for transversely isotropic elastic beams are obtained from the corresponding equations of piezoelectric beams. To illustrate the application of the beam theory developed, a uniformly loaded and simply supported piezoelectric beam is examined.

关键词： rectangular beams, the refined theory, piezoelectric, transversely isotropic.

Neuroglobin mutation associated with hypoxia adaptation in Tibet chicken

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Progress in Natural science:Materials International 2007年第12期17卷 1419-1424页

作者： Zhang Lifan1, Liu Chong2, Lian Linsheng3, zhao Chunjiang1, Bao Haigang1 and Wu Changxin1(1. college of Animal science and Technology, china agricultural university, beijing 100094, china 2. college of Biological science, china agricultural university, beijing 100094, china 3. college of Animal science and Technology, Yunnan agricultural university, Kunming 650201, china) college of Animal science and Technology China Agricultural University Beijing 100094 China college of Biological science China Agricultural University Beijing 100094 China college of Animal science and Technology Yunnan Agricultural University Kunming 650201 China

Globin protein family plays an important role in storing and transporting oxygen. As a newly reported globin, the revealed function of neuroglobin includes binding and storing oxygen as well as facilitating the utilization of oxygen in neuronal cells. In the present study, mutations in exons of chicken Ngb gene were identified with the method of sequencing and created restriction site PCR in Tibet chicken and other four lowland chicken breeds. The mutations of Lys-2224(E4)-Asn and Ser-2279(E4)-Gly were identified in exon 4 of the gene. The Lys-2224(E4)-Asn mutation existed only in Tibet chicken and the mutation frequencies increased with increasing altitude. Analysis of the haplotype and diplotype of the two mutations in Tibet chicken populations of different altitudes showed that the frequencies of TG haplotype and TTGG diplotype also increased with increasing altitude, while the reverse tendency was found on GGAA diplotype. Under the hypoxic simulation incubation, the main haplotype was TG in living embryos and GA in dead embryos. The results showed that the Lys-2224(E4)-Asn mutation may be a specific mutation associated with hypoxia adaptation in Tibet chicken.

关键词： Tibet chicken neuroglobin hypoxia adaptation Ngb gene mutation.

Functional prediction of tomato PLATZ family members and functional verification of Sl PLATZ17

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Journal of Integrative Agriculture 2024年第1期23卷 141-154页

作者： Min xu zhao gao Dalong Li Chen Zhang Yuqi Zhang Qian He Yingbin Qi He Zhang Jingbin Jiang Xiangyang xu Tingting zhao college of Horticulture and Landscape Architecture Northeast Agricultural UniversityHarbin 150030China Key Laboratory of Biology and Genetic Improvement of Horticultural Crops(Northeast Region) Ministry of Agriculture and Rural AffairsHarbin 150030China

PLATZ is a novel zinc finger DNA-binding protein that plays an important role in regulating plant growth and development and resisting abiotic ***,there has been very little research on the function of this family gene in tomatoes,which limits its application in germplasm resource ***,the PLATZ gene family was identified and analyzed in tomato,and its roles were predicted and verified to provide a basis for in-depth research on SlPLATZ gene *** this study,the PLATZ family members of tomato were identified in the whole genome,and 19 SlPLATZ genes were *** prediction was conducted based on gene and promoter structure analysis and RNA-seq-based expression pattern *** genes that responded significantly under different abiotic stresses or were significantly differentially expressed among multiple tissues were screened as functional gene ***17 was selected for functional verification by experiment-based *** results showed that the downregulation of SlPLATZ17 gene expression reduced the drought and salt tolerance of tomato *** plants overexpressing SlPLATZ17 had larger flower sizes and long,thin petals,adjacent petals were not connected at the base,and the stamen circumference was *** study contributes to understanding the functions of the SlPLATZ family in tomato and provides a reference for functional gene screening.

关键词： tomato PLATZ family abiotic stresses plant development

Structural insights into the Oryza sativa cation transporters HKTs in salt tolerance

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Journal of Integrative Plant Biology 2024年第4期66卷 700-708页

作者： Ran gao Yutian Jia Xia xu Peng Fu Jiaqi Zhou Guanghui yang State Key Laboratory of Plant Environmental Resilience Frontiers Science Center for Molecular Design BreedingCollege of Biological SciencesChina Agricultural UniversityBeijing 100193China

The high-affinity potassium transporters(HKTs),selectively permeable to either Na^(+)alone or Na^(+)/K^(+),play pivotal roles in maintaining plant Na^(+)/K^(+)*** their involvement in salt tolerance is widely reported,the molecular underpinnings of Oryza sativa HKTs remain *** this study,we elucidate the structures of OsHKT1;1 and OsHKT2;1,representing two distinct classes of rice *** dimeric assembled OsHKTs can be structurally divided into four *** the dimer interface,a half-helix or a loop in the third domain is coordinated by the C-terminal region of the opposite ***,we present the structures of OsHKT1;5 salt-tolerant and salt-sensitive variants,a key quantitative trait locus associated with salt *** salt-tolerant variant of OsHKT1;5 exhibits enhanced Na^(+)transport capability and displays a more flexible *** findings shed light on the molecular basis of rice HKTs and provide insights into their role in salt tolerance.

关键词： HKT salt-tolerant structure

The MADS-box gene RhAGL6 plays a master role in regulating the receptacle malformation in rose at low temperature

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Horticultural Plant Journal 2024年第5期10卷 1214-1229页

作者： Weikun Jing Shuai Zhang Qingcui zhao yang Liu Liangjun zhao Junping gao Nan Ma Xiaofeng Zhou Yonghong Li School of Food and Drug Shenzhen PolytechnicShenzhen 518055China Department of Ornamental Horticulture College of HorticultureChina Agricultural UniversityBeijing 100193China Postdoctoral Innovation Practice Base Shenzhen PolytechnicShenzhen 518055China Flower Research Institute of Yunnan Academy of agricultural sciences KunmingYunnan 650205China

Low temperature usually results in the developmental deformity of flower organs,immensely affecting the quality of rose ***,it's largely unknown about the regulatory mechanisms activated by low ***,we used a low temperature-sensitive Rosa hybrida cv.‘Peach Avalanche’to screen a MADS-box gene RhAGL6 via conjoint analysis between RNA sequencing(RNA-seq)and whole-genome bisulfite sequencing(WGBS).Furthermore,we found that low temperature induced the hypermethylation and elevated histone 3 lys-27 trimethylation(H3K27me3)level on the RhAGL6 promoter,leading to decreased RhAGL6 *** addition,RhAGL6 silencing resulted in the formation of abnormal *** also found that the levels of gibberellins(GA3)and abscisic acid(ABA)in the receptacle under low temperature were lower and higher,respectively,than under normal *** activity analysis revealed that GA3 significantly activated RhAGL6 promoter activity,whereas ABA inhibited ***,we propose that RhAGL6 regulates rose receptacle development by integrating epigenetic regulation and phytohormones signaling at low temperature.

关键词： Rosa hybrida Low temperature RhAGL6 Receptacle development DNA methylation H3K27me3 Phytohormone

Research on the method for retrieving soil moisture using thermal inertia model

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science china Earth sciences 2006年第5期49卷 539-545页

作者： LIU Zhenhua1 & zhao Yingshi2 1. Information college, South china agricultural university, Guangzhou 510642, china 2. Graduate university of Chinese Academy of sciences, beijing 100049, china Information college South China Agricultural University Guangzhou China Graduate university of Chinese Academy of sciences Beijing China

In order to improve accuracy of soil moisture inversion using remote sensing, a new thermal inertia model is proposed in this paper. The improved model needs only surface maximum temperature as the temperature parameter input instead of input of the surface temperature difference, as well as the surface sensible and latent fluxes are introduced into boundary conditions of thermal conductivity equation. Furthermore, surface soil conductive heat transfer equation of two-layer model is used to solve the soil thermal inertia so that the remote sensing thermal inertia method can be ap- plied to regions with better-covered vegetation, but usually only for the bare areas or worse vegetation covered areas. The model has been tested at several locations in the area of west Inner Mongolia. Comparing the simulation of the new model with the measurements obtained by apparent thermal inertia and by field test, the result shows that the inertia thermal model can be used to estimate soil moisture in more reasonable accuracy.

关键词： thermal model, thermal conductivity equation, soil initial, sensible flux, latent flux, two-layer model.