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Study into grinding force in back grinding of wafer with outer rim

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Advances in Manufacturing 2020年第3期8卷 361-368页

作者： xiang-Long Zhu yu Li zhi-Gang Dong Ren-Ke Kang Shang Gao Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian116024People’s Republic of China

Back grinding of wafer with outer rim(BGWOR)is a new method for carrier-less thinning of silicon *** present,the effects of process parameters on the grinding force remain ***,a BGWOR normal grinding force model based on grain depth-of-cut was established,and the relationship between grinding parameters(wheel infeed rate,wheel rotational speed,and chuck rotational speed)and normal grinding force was ***,a series of experiments were performed to verify the BGWOR normal grinding force *** study proves that the BGWOR normal grinding force is related to the rotational direction of the wheel and chuck,and the effect of grinding mark density on the BGWOR normal grinding force cannot be ***,this study provides methods for reducing the grinding force and optimizing the back thinning process of the silicon wafer.

关键词： Silicon wafer Back grinding of wafer with outer rim(BGWOR) Grinding force Grinding mark density

A universal probe for simultaneous detection of six pospiviroids and natural infection of potato spindle tuber viroid(PSTVd) in tomato in China

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Journal of Integrative Agriculture 2023年第3期22卷 790-798页

作者： ZHANG yu-hong LI zhi-xin DU Ya-jie LI Shi-fang ZHANG zhi-xiang State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijing 100193P.R.China Keshan Branch of Heilongjiang Academy of Agricultural Sciences Qiqihar 161005P.R.China College of Agronomy and Biotechnology Hebei Normal University of Science&TechnologyQinhuangdao 066004P.R.China

Several viroids in the genus Pospiviroid can infect tomato(Solanum lycopersicum)and cause severe diseases,posing a serious threat to tomato *** simultaneous detection of six tomato-infecting pospiviroids-columnea latent viroid(CLVd),pepper chat fruit viroid(PCFVd),potato spindle tuber viroid(PSTVd),tomato apical stunt viroid(TASVd),tomato chlorotic dwarf viroid(TCDVd),and tomato planta macho viroid(TPMVd),we developed a universal probe based on a highly conserved 61 nt long sequence shared among *** with their specific probes,the universal probe has a similar,though slightly reduced,detection sensitivity and has the advantages of simple and cost-effective preparation and simultaneous detection of the six *** addition,the universal probe was used in dot-blot hybridization assays for a large-scale survey of viroid(s)in tomato plantings in *** PSTVd was detected in a few greenhouse-planted tomato *** analysis revealed that these tomato PSTVd isolates may have been introduced from tomato seeds imported from abroad.

关键词： tomato viroid simultaneous detection molecular hybridization pospiviroids

The form-invariance of wave equations without requiring a priori relations between field variables

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Science China(Physics,Mechanics & Astronomy) 2014年第12期57卷 2285-2296页

作者： xiang zhi Hai Key Laboratory of Applied Mechanics Department of Engineering Mechanics Tsinghua University

According to the principle of relativity,the equations describing the laws of physics should have the same forms in all admissible frames of reference,i.e.,form-invariance is an intrinsic property of correct wave ***,so far in the design of metamaterials by transformation methods,the form-invariance is always proved by using certain relations between field variables before and after coordinate *** main contribution of this paper is to give general proofs of form-invariance of electromagnetic,sound and elastic wave equations in the global Cartesian coordinate system without using any assumption of the relation between field *** results show that electromagnetic wave equations and sound wave equations are intrinsically form-invariant,but traditional elastodynamic equations are *** a by-product,one can naturally obtain new elastodynamic equations in the time domain that are locally accurate to describe the elastic wave propagation in inhomogeneous *** validity of these new equations is demonstrated by some numerical simulations of a perfect elastic wave rotator and an approximate elastic wave *** findings are important for solving inverse scattering problems in many fields such as seismology,nondestructive evaluation and metamaterials.

关键词： wave equations transformation methods inhomogeneity metamaterials

Nichols algebras over weak Hopf algebras

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Applied Mathematics(A Journal of Chinese Universities) 2018年第1期33卷 107-126页

作者： WU zhi-xiang School of Mathematical Science Zhejiang University

In this paper, we study a Yetter-Drinfeld module V over a weak Hopf algebra *** the category of all left H-modules is not a braided tensor category, we can define a Yetter-Drinfeld module. Using this Yetter-Drinfeld modules V, we construct Nichols algebra B(V) over the weak Hopf algebra H, and a series of weak Hopf algebras. Some results of [8] are generalized.

关键词： quantum enveloping algebra Nichols algebra weak Hopf algebra

The Global Attractor of a Non-Local PDE Model with Delay for Population Dynamics in Rn

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Acta Mathematica Sinica,English Series 2011年第6期27卷 1121-1136页

作者： xiang LI zhi xiang LI Department of Mathematics and Systems Science College of ScienceNational University of Defense Technology Changsha 410073 P. R. China

In this paper, we consider a non-local PDE model with delay for population dynamics in Rn. First, we prove the existence and uniqueness of weak solutions under some suitable decayed assumptions on non-local term at infinity. Then, we obtain the global attractor by proving w-limit compactness property of the solution operator semigroup.

关键词： Non-local PDE model w-limit compact global attractor

Construct Weak Hopf Algebras by Using Borcherds Matrix

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Acta Mathematica Sinica,English Series 2009年第8期25卷 1337-1352页

作者： zhi xiang WU Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China

We define a new kind quantized enveloping algebra of a generalized Kac-Moody algebra by adding a new generator J satisfying jm = j for some integer m. We denote this algebra by wUqT（A）. This algebra is a weak Hopf algebra if and only if m = 2,3. In general, it is a bialgebra, and contains a Hopf subalgebra. This Hopf subalgebra is isomorphic to the usual quantum envelope algebra Uq （A） of a generalized Kac-Moody algebra A.

关键词： generalized Kac-Moody algebras irreducible representation weak Hopf algebra

Analyses of dynamic characteristics of a fluid-filled thin rectangular porous plate with various boundary conditions

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Acta Mechanica Solida Sinica 2017年第1期30卷 87-97页

作者： yu xiang Automotive and Transportation Engineering Collage Guangxi University of Science and Technology Liuzhou 545006 China Guangxi Key Laboratory of Automobile Components and Vehicle Technology Guangxi University of Science and Technology Liuzhou 545006 China

Based on the classical theory of thin plate and Biot theory, a precise model of the transverse vibrations of a thin rectangular porous plate is proposed. The first order differential equations of the porous plate are derived in the frequency domain. By considering the coupling effect between the solid phase and the fluid phase and without any hypothesis for the fluid displacement, the model presented here is rigorous and close to the real materials. Owing to the use of extended homogeneous capacity precision integration method and precise element method, the model can be applied in higher frequency range than pure numerical methods. This model also easily adapts to various boundary conditions. Numerical results are given for two different porous plates under different excitations and boundary conditions.

关键词： Thin rectangular porous plate Blot theory Vibration First order differential equations Extended homogeneous capacity high precision integration method

Genome-wide identification and expression analysis of auxin response factor(ARF) gene family in strawberry(Fragaria vesca)

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Journal of Integrative Agriculture 2019年第7期18卷 1587-1603页

作者： WANG Shao-xi SHI Feng-yan DONG xiang-xiang LI yu-xiang ZHANG zhi-hong LI He College of Horticulture Shenyang Agricultural University/Liaoning Key Laboratory of Strawberry Breeding and Cultivation

Auxin signaling plays a significant role in the whole process of plant growth and development from embryogenesis to *** response factors(ARFs) are reported to regulate the expression of auxin response genes by binding to auxin response *** is the most critical transcription factor family which has been released in most species,but few reports in *** this study,the structure characterization of 12 FvARF genes in strawberry,their expression patterns at different development stages,different organizations,and different indole-3-acetic acid(IAA) treatments were *** expression of 12 FvARFs was found in all experiment tissues and showed almost the same trend during fruit *** FvARFs respond to the treatment of *** study provides comprehensive information on ARF family in strawberry,including gene structures,chromosome locations,phylogenetic relationships and expression *** information on FvARF genes paves the way for future research on strawberry ARF genes.

关键词： auxin auxin response factor Fragaria vesca gene structure gene expression

miR-21 targets and inhibits tumor suppressor gene PTEN to promote prostate cancer cell proliferation and invasion:An experimental study

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Asian Pacific Journal of Tropical Medicine 2017年第1期10卷 84-87页

作者： yu Yang Jia-xiang Guo zhi-Qiang Shao Department of Urology the First Affiliated Hospital of PLA General HospitalBeijing 100048China

Objective: To study whether miR-21 targets and inhibits tumor suppressor gene PTEN can promote prostate cancer cell proliferation and invasion. Methods: Prostate cancer cell lines PC-3 were cultured and divided into negative control group (NC group), miR-21 group, pcDNA3.1 group, miR-21+pcDNA3.1 group and miR-21+PTEN group that were transfected with different miR and plasmid, respectively. After 12 h and 24 h of transfection, the cell viability and invasive cell number were determined; after 24 h of transfection, Bcl-2, Survivin, MMP2, MMP9, PTEN, PI3K, and AKT expression in cells were determined. Results: After 12 h and 24 h of transfection, OD value and invasive cell number of miR-21 group were significantly higher than those of NC group; after 24 h of transfection, Bcl-2, Survivin, MMP2, MMP9, PI3K and AKT expression levels were significantly higher than those of NC group while PTEN expression level was significantly lower than that of NC group; after 12 h and 24 h of transfection, OD value and invasive cell number of miR-21+pcDNA3.1 group were significantly higher than those of pcDNA3.1 group, and the OD value and invasive cell number of 1niR-21+PTEN group were significantly lower than those of miR-21+pcDNA3.1 group; after 24 h of transfection, Bcl-2, Survivin, MMP2 and MMP9 content of miR-21+pcDNA3.1 group were significantly higher than those of pcDNA3.1 group, and Bcl-2, Survivin, MMP2 and MMP9 content of miR-21+PTEN group were significantly lower than those of miR-21+pcDNA3.1 group. Conclusions: miR-21 can target and inhibit tumor suppressor gene PTEN expression to promote prostate cancer cell proliferation and invasion.

关键词： Prostate cancer miR-2 PTEN Proliferation Invasion