A normal orthodox semigroup is an orthodox semigroup whose idempotent elements form a normal band.We deal with congruces on a normal orthodox semigroup with an iverse transversal .A structure theorem for such semigrou...A normal orthodox semigroup is an orthodox semigroup whose idempotent elements form a normal band.We deal with congruces on a normal orthodox semigroup with an iverse transversal .A structure theorem for such semigroup is obtained.Munn(1966)gave a fundamental inverse semigroup Following Munn's idea ,we give a fundamental normal orthodox semigroup with an inverse transversal.展开更多
For a regular semigroup with an inverse transversal, we have Saito’s structure W(I, S°, Λ, *, α,β). We represent congruences on this kind of semigroups by the so-called congruence assemblage which consist of ...For a regular semigroup with an inverse transversal, we have Saito’s structure W(I, S°, Λ, *, α,β). We represent congruences on this kind of semigroups by the so-called congruence assemblage which consist of congruences on the structure component parts I, S° and Λ. The structure of images of this type of semigroups is also presented.展开更多
It is well known that the subclass of inverse semigroups and the subclass of completely regular semigroups of the class of regular semigroups form the so called e-varieties of semigroups. However, the class of regular...It is well known that the subclass of inverse semigroups and the subclass of completely regular semigroups of the class of regular semigroups form the so called e-varieties of semigroups. However, the class of regular semigroups with inverse transversals does not belong to this variety. We now call this class of semigroups the ist-variety of semigroups, and denote it by IST . In this paper, we consider the class of orthodox semigroups with inverse transversals, which is a special ist-variety and is denoted by OIST . Some previous results given by Tang and Wang on this topic are extended. In particular, the structure of free bands with inverse transversals is investigated. Results of McAlister, McFadden, Blyth and Saito on semigroups with inverse transversals are hence generalized and enriched.展开更多
Let S be a regular semigroup, S° an inverse subsemigroup of S.S° is called a generalized inverse transversal of S, if V（x）∩S°≠Ф. In this paper, some properties of this kind of semigroups are discus...Let S be a regular semigroup, S° an inverse subsemigroup of S.S° is called a generalized inverse transversal of S, if V（x）∩S°≠Ф. In this paper, some properties of this kind of semigroups are discussed. In particular, a construction theorem is obtained which contains some recent results in the literature as its special cases.展开更多
Ultrasonic guided waves(UGWs),which propagate throughout the entire thickness of cortical bone,are attractive for the early diagnosis of osteoporosis.However,this is challenging due to the impact of soft tissue and th...Ultrasonic guided waves(UGWs),which propagate throughout the entire thickness of cortical bone,are attractive for the early diagnosis of osteoporosis.However,this is challenging due to the impact of soft tissue and the inherent difficulties related to multiparametric inversion of cortical bone quality factors,such as cortical thickness and bulk wave velocity.Therefore,in this research,a UGW-based multi-parameter inversion algorithm is developed to predict strength-related factors.In simulation,a free plate(cortical bone)and a bilayer plate(soft tissue and cortical bone)are used to validate the proposed method.The inversed cortical thickness(CTh),longitudinal velocity(V_(L))and transverse velocity(V_(T))are in accordance with the true values.Then four bovine cortical bone plates were used in in vitro experiments.Compared with the reference values,the relative errors for cortical thickness were 3.96%,0.83%,2.87%,and 4.25%,respectively.In the in vivo measurements,UGWs are collected from the tibias of 10 volunteers.The theoretical dispersion curves depicted by the estimated parameters(V_(T),V_(L),CTh)match well with the extracted experimental ones.In comparison with dual-energy x-ray absorptiometry,our results show that the estimated transverse velocity and cortical thickness are highly sensitive to osteoporosis.Therefore,these two parameters(CTh and V_(T))of long bones have potential to be used for diagnosis of bone status in clinical applications.展开更多
The dispersion curves of real-valued modes in a fluid-filled borehole are widely used in acoustic well logging.The accurate dispersion curves are the precondition of theoretical analysis and inversion process.Generall...The dispersion curves of real-valued modes in a fluid-filled borehole are widely used in acoustic well logging.The accurate dispersion curves are the precondition of theoretical analysis and inversion process.Generally,these curves can be obtained by solving the conventional dispersion equation for isotropic formations and most vertically transverse isotropy(VTI)formations.However,if the real-valued solutions exist when the radial wavenumbers for the formation quasi-P and quasi-S equals to each other,the existed methods based on the conventional dispersion equation could lead to incorrect results for some VTI formations.Few studies have focused on the influence of these real-valued solutions on dispersion curve extraction.To remove these real-valued solutions,we have proposed a modified dispersion equation and its corresponding solving process.When solving the dispersion equation,the Scholte wave velocity of VTI formation at high frequency is used as the initial guess.The two synthetic examples including fast and slow VTI formations validate that these real-valued solutions do not contribute to the wavefield,and the new dispersion curve extraction method is suitable for all kinds of VTI formations.Consequently,the method can provide reliable dispersion curves for both theoretical analysis and anisotropic parameters inversion in VTI formations.展开更多
In this paper,a complete congruence on the congruence lattice of regular semigroups with Q-inverse transversals is analysed.The classes of this complete congruence which are intervals are discussed and their least and...In this paper,a complete congruence on the congruence lattice of regular semigroups with Q-inverse transversals is analysed.The classes of this complete congruence which are intervals are discussed and their least and greatest elements are presented clearly.展开更多
Let S be a regular semigroup with an inverse transversal S° and C（S） the congruence lattice of S. A relation K° on C（S） is introduced as follows： if p, θ∈ C（S）, then we say that p and 0 are K°-...Let S be a regular semigroup with an inverse transversal S° and C（S） the congruence lattice of S. A relation K° on C（S） is introduced as follows： if p, θ∈ C（S）, then we say that p and 0 are K°-related if Ker pO = Ker θ°, where p°= p｜s°. Expressions for the least and the greatest congruences in the same K°-class as p are provided. A number of equivalent conditions for K° being a congruence are given.展开更多
为研究胡萝卜切片在干燥过程中内部水分变化的特征,采用电热恒温干燥箱在40、50、60、70和80℃的条件下对胡萝卜切片进行热风干燥试验,应用低场核磁共振(low field nuclear magnetic resonance,LF-NMR)的横向弛豫时间(T2)反演谱分析胡...为研究胡萝卜切片在干燥过程中内部水分变化的特征,采用电热恒温干燥箱在40、50、60、70和80℃的条件下对胡萝卜切片进行热风干燥试验,应用低场核磁共振(low field nuclear magnetic resonance,LF-NMR)的横向弛豫时间(T2)反演谱分析胡萝卜切片在干燥过程中内部水分的变化。试验结果表明:干燥过程改变了胡萝卜样品中水的结合状态,自由度高的水分向自由度低的迁移;随着干燥温度升高,干燥速率加快,但温度为80℃时,由于物料表面结壳阻碍了水分的外迁从而影响干燥速率。试验数据为果疏变温联合干燥工艺和干燥转换点的确定提供参考。展开更多
文摘A normal orthodox semigroup is an orthodox semigroup whose idempotent elements form a normal band.We deal with congruces on a normal orthodox semigroup with an iverse transversal .A structure theorem for such semigroup is obtained.Munn(1966)gave a fundamental inverse semigroup Following Munn's idea ,we give a fundamental normal orthodox semigroup with an inverse transversal.
基金Supported by National Natural Science Foundation of China（90818020） Supported by Scientific Research Foundation of China Jiliang University（20060810）
基金This work is supported by Natural Science Foundation of Guangdong Province
文摘For a regular semigroup with an inverse transversal, we have Saito’s structure W(I, S°, Λ, *, α,β). We represent congruences on this kind of semigroups by the so-called congruence assemblage which consist of congruences on the structure component parts I, S° and Λ. The structure of images of this type of semigroups is also presented.
基金supported by National Natural Science Foundation of China (Grant No.10571061)
文摘It is well known that the subclass of inverse semigroups and the subclass of completely regular semigroups of the class of regular semigroups form the so called e-varieties of semigroups. However, the class of regular semigroups with inverse transversals does not belong to this variety. We now call this class of semigroups the ist-variety of semigroups, and denote it by IST . In this paper, we consider the class of orthodox semigroups with inverse transversals, which is a special ist-variety and is denoted by OIST . Some previous results given by Tang and Wang on this topic are extended. In particular, the structure of free bands with inverse transversals is investigated. Results of McAlister, McFadden, Blyth and Saito on semigroups with inverse transversals are hence generalized and enriched.
文摘Let S be a regular semigroup, S° an inverse subsemigroup of S.S° is called a generalized inverse transversal of S, if V（x）∩S°≠Ф. In this paper, some properties of this kind of semigroups are discussed. In particular, a construction theorem is obtained which contains some recent results in the literature as its special cases.
基金the National Natural Science Foundation of China(Grant No.12034005)in part by the Program of Shanghai Academic Research Leader(Grant No.19XD1400500)in part by the China Postdoctoral Science Foundation(Grant No.2019M661334)。
文摘Ultrasonic guided waves(UGWs),which propagate throughout the entire thickness of cortical bone,are attractive for the early diagnosis of osteoporosis.However,this is challenging due to the impact of soft tissue and the inherent difficulties related to multiparametric inversion of cortical bone quality factors,such as cortical thickness and bulk wave velocity.Therefore,in this research,a UGW-based multi-parameter inversion algorithm is developed to predict strength-related factors.In simulation,a free plate(cortical bone)and a bilayer plate(soft tissue and cortical bone)are used to validate the proposed method.The inversed cortical thickness(CTh),longitudinal velocity(V_(L))and transverse velocity(V_(T))are in accordance with the true values.Then four bovine cortical bone plates were used in in vitro experiments.Compared with the reference values,the relative errors for cortical thickness were 3.96%,0.83%,2.87%,and 4.25%,respectively.In the in vivo measurements,UGWs are collected from the tibias of 10 volunteers.The theoretical dispersion curves depicted by the estimated parameters(V_(T),V_(L),CTh)match well with the extracted experimental ones.In comparison with dual-energy x-ray absorptiometry,our results show that the estimated transverse velocity and cortical thickness are highly sensitive to osteoporosis.Therefore,these two parameters(CTh and V_(T))of long bones have potential to be used for diagnosis of bone status in clinical applications.
基金financial support provided by the National Natural Science Foundation of China(Grant No.42104127 and 42004117)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(Grant No.162301192696).
文摘The dispersion curves of real-valued modes in a fluid-filled borehole are widely used in acoustic well logging.The accurate dispersion curves are the precondition of theoretical analysis and inversion process.Generally,these curves can be obtained by solving the conventional dispersion equation for isotropic formations and most vertically transverse isotropy(VTI)formations.However,if the real-valued solutions exist when the radial wavenumbers for the formation quasi-P and quasi-S equals to each other,the existed methods based on the conventional dispersion equation could lead to incorrect results for some VTI formations.Few studies have focused on the influence of these real-valued solutions on dispersion curve extraction.To remove these real-valued solutions,we have proposed a modified dispersion equation and its corresponding solving process.When solving the dispersion equation,the Scholte wave velocity of VTI formation at high frequency is used as the initial guess.The two synthetic examples including fast and slow VTI formations validate that these real-valued solutions do not contribute to the wavefield,and the new dispersion curve extraction method is suitable for all kinds of VTI formations.Consequently,the method can provide reliable dispersion curves for both theoretical analysis and anisotropic parameters inversion in VTI formations.
基金Foundation item： the National Natural Science Foundation of China （No. 10571061） the Science Foundation of Guangdong Province （No. 0501332） and the Science Foundation of the Department of Education of Yunnan Province （No. 07C10110）.
文摘In this paper,a complete congruence on the congruence lattice of regular semigroups with Q-inverse transversals is analysed.The classes of this complete congruence which are intervals are discussed and their least and greatest elements are presented clearly.
文摘Let S be a regular semigroup with an inverse transversal S° and C（S） the congruence lattice of S. A relation K° on C（S） is introduced as follows： if p, θ∈ C（S）, then we say that p and 0 are K°-related if Ker pO = Ker θ°, where p°= p｜s°. Expressions for the least and the greatest congruences in the same K°-class as p are provided. A number of equivalent conditions for K° being a congruence are given.
文摘为研究胡萝卜切片在干燥过程中内部水分变化的特征,采用电热恒温干燥箱在40、50、60、70和80℃的条件下对胡萝卜切片进行热风干燥试验,应用低场核磁共振(low field nuclear magnetic resonance,LF-NMR)的横向弛豫时间(T2)反演谱分析胡萝卜切片在干燥过程中内部水分的变化。试验结果表明:干燥过程改变了胡萝卜样品中水的结合状态,自由度高的水分向自由度低的迁移;随着干燥温度升高,干燥速率加快,但温度为80℃时,由于物料表面结壳阻碍了水分的外迁从而影响干燥速率。试验数据为果疏变温联合干燥工艺和干燥转换点的确定提供参考。
