Let F_(1)be the virtual field consisting of one element and(Q,I)a string pair.In this paper,we study the representations of string pairs over the virtual field F_(1).It is proved that an indecomposable F_(1)-represent...Let F_(1)be the virtual field consisting of one element and(Q,I)a string pair.In this paper,we study the representations of string pairs over the virtual field F_(1).It is proved that an indecomposable F_(1)-representation is either a string representation or a band representation by using the coefficient quivers.It is worth noting that for a given band and a positive integer,there exists a unique band representation up to isomorphism.展开更多
In this paper, in Section 1, we have described some equations and theorems concerning the Lebesgue integral and the Lebesgue measure. In Section 2, we have described the possible mathematical applications, of Lebesgue...In this paper, in Section 1, we have described some equations and theorems concerning the Lebesgue integral and the Lebesgue measure. In Section 2, we have described the possible mathematical applications, of Lebesgue integration, in some equations concerning various sectors of Chern-Simons theory and Yang-Mills gauge theory, precisely the two dimensional quantum Yang-Mills theory. In conclusion, in Section 3, we have described also the possible mathematical connections with some sectors of String Theory and Number Theory, principally with some equations concerning the Ramanujan’s modular equations that are related to the physical vibrations of the bosonic strings and of the superstrings, some Ramanujan’s identities concerning π and the zeta strings.展开更多
A new phenomenological model(axionic QCD string)is constructed to study the topological issues of the QCD vacuum and hadron structure.It provides an alternative way of tackling the Strong CP problem,which is different...A new phenomenological model(axionic QCD string)is constructed to study the topological issues of the QCD vacuum and hadron structure.It provides an alternative way of tackling the Strong CP problem,which is different from the traditional Peccei–Quinn approach.Neither new particle nor extra symmetry is introduced,and the role of the Peccei–Quinn axion is played by a quasiparticle arising from the phase of the quark condensate,dubbed as axionic excitation.The derivative of this excitation field is decomposed into a regular part and a singular part,and the latter contains vorticity from the string configuration.A hidden gauge symmetry is revealed in this decomposition and vorticity is represented by an emergent gauge field associated with anomalies.These components,together with the anomaly-inflow mechanism,complete the effective Lagrangian description for the axionic QCD string.展开更多
In this paper we consider a static spherically symmetric black hole(BH)embedded in a Dehnen-(1,4,0)-type dark matter(DM)halo in the presence of a cloud string.We examine and present data on how the core density of the...In this paper we consider a static spherically symmetric black hole(BH)embedded in a Dehnen-(1,4,0)-type dark matter(DM)halo in the presence of a cloud string.We examine and present data on how the core density of the DM halo parameter and the cloud string parameter affect BH attributes such as quasinormal modes(QNMs)and shadow cast.To do this,we first look into the effective potential of perturbation equations for three types of perturbation fields with different spins:massless scalar field,electromagnetic field and gravitational field.Then,using the sixth-order Wentzel-Kramers-Brillouin approximation,we examine QNMs of the BH disturbed by the three fields and derive quasinormal frequencies.The changes in QNM versus the core density parameter and the cloud string parameter for three disturbances are explored.We also investigate how the core density and the cloud string parameter affect the photon sphere and shadow radius.Interestingly,the study shows that the influence of Dehnen-type DM and cloud strings increases both the photon sphere and the shadow radius.Finally,we employ observational data from Sgr A^(*) and M87^(*) to set limitations on the BH parameters.展开更多
During drilling operations,cyclic loading is exerted on the wellbore wall by the vibrations of the drill string.This loading could lead to rock fatigue,which in turn might result in wellbore failure.In this study,a nu...During drilling operations,cyclic loading is exerted on the wellbore wall by the vibrations of the drill string.This loading could lead to rock fatigue,which in turn might result in wellbore failure.In this study,a numerical model is developed to simulate the effects of repeated loading on rock fatigue and failure.The simulation is based on an elasto-plastic constitutive model coupled with a damage mechanics approach,which allows us to examine the wellbore instability due to drill string vibrations.The model is verified with the existing data in the literature related to experiments on impact of a steel ball against a curved wall.The findings indicate that cyclic loading increases the development of plastic strain around the wellbore significantly compared to static conditions,promoting rock fatigue.Furthermore,the cyclic loading expands the radius of the yielded zone substantially,a critical factor for maintaining wellbore integrity.The proposed model can be used to evaluate the wellbore stability under repetitive loading caused by the drill string action.展开更多
This is a writeup of lectures delivered at the Asian Pacific Introductory School on Superstring and Related Topics in Beijing(2006)and an expanded version of these lectures given at the Third Summer School on Strings,...This is a writeup of lectures delivered at the Asian Pacific Introductory School on Superstring and Related Topics in Beijing(2006)and an expanded version of these lectures given at the Third Summer School on Strings,Fields and Holography in Nanjing(2023).It aims to provide both a historical and pedagogical account of developments in finding 1/2 Bogomol?nyi–Prasad–Sommerfield(BPS)extended string solitons during the early stage of the so-called second string revolution,before which these objects were thought to be unrelated to strings.Nonsupersymmetric solutions related to brane/anti brane systems or non-BPS systems are also discussed.展开更多
The complex vibration directly affects the dynamic safety of drill string in ultra-deep wells and extra-deep wells.It is important to understand the dynamic characteristics of drill string to ensure the safety of dril...The complex vibration directly affects the dynamic safety of drill string in ultra-deep wells and extra-deep wells.It is important to understand the dynamic characteristics of drill string to ensure the safety of drill string.Due to the super slenderness ratio of drill string,strong nonlinearity implied in dynamic analysis and the complex load environment,dynamic simulation of drill string faces great challenges.At present,many simulation methods have been developed to analyze drill string dynamics,and node iteration method is one of them.The node iteration method has a unique advantage in dealing with the contact characteristics between drill string and borehole wall,but its drawback is that the calculation consumes a considerable amount of time.This paper presents a dynamic simulation method of drilling string in extra-deep well based on successive over-relaxation node iterative method(SOR node iteration method).Through theoretical analysis and numerical examples,the correctness and validity of this method were verified,and the dynamics characteristics of drill string in extra-deep wells were calculated and analyzed.The results demonstrate that,in contrast to the conventional node iteration method,the SOR node iteration method can increase the computational efficiency by 48.2%while achieving comparable results.And the whirl trajectory of the extra-deep well drill string is extremely complicated,the maximum rotational speed downhole is approximately twice the rotational speed on the ground.The dynamic torque increases rapidly at the position of the bottom stabilizer,and the lateral vibration in the middle and lower parts of drill string is relatively intense.展开更多
BACKGROUND Traditional esophagogastroduodenoscopy(EGD),an invasive examination method,can cause discomfort and pain in patients.In contrast,magnetically controlled capsule endoscopy(MCE),a noninvasive method,is being ...BACKGROUND Traditional esophagogastroduodenoscopy(EGD),an invasive examination method,can cause discomfort and pain in patients.In contrast,magnetically controlled capsule endoscopy(MCE),a noninvasive method,is being applied for the detection of stomach and small intestinal diseases,but its application in treating esophageal diseases is not widespread.AIM To evaluate the safety and efficacy of detachable string MCE(ds-MCE)for the diagnosis of esophageal diseases.METHODS Fifty patients who had been diagnosed with esophageal diseases were pros-pectively recruited for this clinical study and underwent ds-MCE and conven-tional EGD.The primary endpoints included the sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy of ds-MCE for patients with esophageal diseases.The secondary endpoints consisted of visualizing the esophageal and dentate lines,as well as the subjects'tolerance of the procedure.RESULTS Using EGD as the gold standard,the sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy of ds-MCE for esophageal disease detection were 85.71%,86.21%,81.82%,89.29%,and 86%,respectively.ds-MCE was more comfortable and convenient than EGD was,with 80%of patients feeling that ds-MCE examination was very comfortable or comfortable and 50%of patients believing that detachable string v examination was very convenient.CONCLUSION This study revealed that ds-MCE has the same diagnostic effects as traditional EGD for esophageal diseases and is more comfortable and convenient than EGD,providing a novel noninvasive method for treating esophageal diseases.展开更多
Objective:This study aims to explore the expression patterns of cysteine string protein alpha(CSPα)and cysteine string protein beta(CSPβ)in the mammalian inner ear,with an emphasis on their temporal dynamics during ...Objective:This study aims to explore the expression patterns of cysteine string protein alpha(CSPα)and cysteine string protein beta(CSPβ)in the mammalian inner ear,with an emphasis on their temporal dynamics during the developmental stages of C57BL/6 mice.Methods:We utilized immunofluorescence staining to assess the localization and distribution of CSPαand CSPβwithin the inner ears of C57BL/6 mice and miniature pigs.Additionally,this method facilitated the investigation of their temporal expression profiles.Results:In adult C57BL/6 mice and miniature pigs,CSPαand CSPβwere identified in the cytoplasm of inner hair cells and spiral ganglion cells,yet were absent in outer hair cells.Both proteins were found to colocalize with Ctbp2 on the basal side of the cytoplasm in inner hair cells’basilar membrane.Expression of CSPαwas observed at the nerve fiber termini at the basilar membrane’s base of inner and outer hair cells 10 days postnatally in C57BL/6 mice.Notably,expression of both CSPαand CSPβin the cytoplasm of inner hair cells emerged on the 12th day post-birth,aligning with the timeline for registering cochlear potentials.The expression levels of both proteins increased with age,but were consistently absent in outer hair cells.Contrastingly,expression of CSPαand CSPβwas present in the cytoplasm of inner hair cells in miniature pigs as early as one day post-birth,yet remained absent in the three rows of outer hair cells.Conclusion:CSPαand CSPβexhibit predominant and specific expression in inner hair cells and spiral ganglion cells.A unique expression pattern was observed for CSPα,which was also present at the nerve fiber endings of both inner and outer hair cells.The developmental expression trajectory of CSPαand CSPβin mouse inner hair cells is characterized by an initial absence,followed by a gradual increase.Moreover,the timing of expression onset between mice and miniature pigs indicates distinct temporal dynamics,suggesting a potential role in auditory development.展开更多
Using real fields instead of complex ones, it is suggested here that the fermions are pairs of coupled strings with an internal tension. The interaction between the two coupled strings is due to an exchange mechanism ...Using real fields instead of complex ones, it is suggested here that the fermions are pairs of coupled strings with an internal tension. The interaction between the two coupled strings is due to an exchange mechanism which is proportional to Planck’s constant. This may be the result of two massless bosons (hypergluons) coupled by a preon (prequark) exchange. It also gives a physical explanation to the origin of the Planck constant, and origin of spin.展开更多
A model for particles based on preons in chiral, vector and tensor/graviton supermultiplets of unbroken global supersymmetry is engineered. The framework of the model is little string theory. Phenomenological predicti...A model for particles based on preons in chiral, vector and tensor/graviton supermultiplets of unbroken global supersymmetry is engineered. The framework of the model is little string theory. Phenomenological predictions are discussed.展开更多
We compare, following Pati, global symmetries, our topological supersymmetric preon model with the heterotic E<sub>8</sub> × E<sub>8</sub> string theory. We include Pati’s supergravity ba...We compare, following Pati, global symmetries, our topological supersymmetric preon model with the heterotic E<sub>8</sub> × E<sub>8</sub> string theory. We include Pati’s supergravity based preon model in this work and compare the preon interactions of his model to ours. Based on preon-string symmetry comparison and preon phenomenological results, we conclude that the fundamental particles are likely preons rather than standard model particles. .展开更多
Edward Witten has been described as“the most brilliant physicist of his generation”,and some even compare him to Isaac Newton.A deeply original and dedicated theoretical physicist,Witten's primary focus is strin...Edward Witten has been described as“the most brilliant physicist of his generation”,and some even compare him to Isaac Newton.A deeply original and dedicated theoretical physicist,Witten's primary focus is string theory—a“theory of everything”that proposes the universe's fundamental components are curves,or“strings”arranged in loops.in loops.He has been a leading advocate and influential contributor in this field,famously stating,“It was very clear that if I didn't spend my life concentrating on string theory,I would simply be missing my life's calling.”展开更多
为了研究复杂温压场下钻柱系统动力学特性,综合考虑了钻头-岩石相互作用,温度和压力对钻井液性能影响、温度对钻柱几何尺寸与特性影响以及钻柱系统所受轴向与扭转方向耦合振动,基于状态依赖时滞方法建立了4自由度直井钻柱系统动力学模型...为了研究复杂温压场下钻柱系统动力学特性,综合考虑了钻头-岩石相互作用,温度和压力对钻井液性能影响、温度对钻柱几何尺寸与特性影响以及钻柱系统所受轴向与扭转方向耦合振动,基于状态依赖时滞方法建立了4自由度直井钻柱系统动力学模型,分析了钻压(weight on bit,WOB)、驱动转速、钻井液密度以及地温梯度对系统动力学特性的影响。在此基础上,探究了WOB和驱动转速,钻井液密度和地温梯度对钻柱系统最小速度的影响规律。研究结果表明:增大钻压与钻井液密度会加剧钻柱系统振动程度,造成钻头黏滑振动;增加转速可以抑制黏滑振动;随着地温梯度的增加,会使钻头跳钻问题与黏滑振动更为严重;合理选择钻压与驱动转速能够避免黏滑振动,提高钻进效率;钻井液密度与地温梯度对钻柱系统的影响使得其最小速度呈现出一种非线性、无明显规律的特征,需要根据现场工况,结合模型进行参数优选。展开更多
文摘Let F_(1)be the virtual field consisting of one element and(Q,I)a string pair.In this paper,we study the representations of string pairs over the virtual field F_(1).It is proved that an indecomposable F_(1)-representation is either a string representation or a band representation by using the coefficient quivers.It is worth noting that for a given band and a positive integer,there exists a unique band representation up to isomorphism.
文摘In this paper, in Section 1, we have described some equations and theorems concerning the Lebesgue integral and the Lebesgue measure. In Section 2, we have described the possible mathematical applications, of Lebesgue integration, in some equations concerning various sectors of Chern-Simons theory and Yang-Mills gauge theory, precisely the two dimensional quantum Yang-Mills theory. In conclusion, in Section 3, we have described also the possible mathematical connections with some sectors of String Theory and Number Theory, principally with some equations concerning the Ramanujan’s modular equations that are related to the physical vibrations of the bosonic strings and of the superstrings, some Ramanujan’s identities concerning π and the zeta strings.
基金supported by the Natural Science Foundation of Fujian Province(Grant No.2022J011130)the Research Starting Grant from Minjiang University(Grant No.30804317)。
文摘A new phenomenological model(axionic QCD string)is constructed to study the topological issues of the QCD vacuum and hadron structure.It provides an alternative way of tackling the Strong CP problem,which is different from the traditional Peccei–Quinn approach.Neither new particle nor extra symmetry is introduced,and the role of the Peccei–Quinn axion is played by a quasiparticle arising from the phase of the quark condensate,dubbed as axionic excitation.The derivative of this excitation field is decomposed into a regular part and a singular part,and the latter contains vorticity from the string configuration.A hidden gauge symmetry is revealed in this decomposition and vorticity is represented by an emergent gauge field associated with anomalies.These components,together with the anomaly-inflow mechanism,complete the effective Lagrangian description for the axionic QCD string.
基金supported by the National Natural Science Foundation of China under Grant No.11675143the National Key Research and Development Program of China under Grant No.2020YFC2201503。
文摘In this paper we consider a static spherically symmetric black hole(BH)embedded in a Dehnen-(1,4,0)-type dark matter(DM)halo in the presence of a cloud string.We examine and present data on how the core density of the DM halo parameter and the cloud string parameter affect BH attributes such as quasinormal modes(QNMs)and shadow cast.To do this,we first look into the effective potential of perturbation equations for three types of perturbation fields with different spins:massless scalar field,electromagnetic field and gravitational field.Then,using the sixth-order Wentzel-Kramers-Brillouin approximation,we examine QNMs of the BH disturbed by the three fields and derive quasinormal frequencies.The changes in QNM versus the core density parameter and the cloud string parameter for three disturbances are explored.We also investigate how the core density and the cloud string parameter affect the photon sphere and shadow radius.Interestingly,the study shows that the influence of Dehnen-type DM and cloud strings increases both the photon sphere and the shadow radius.Finally,we employ observational data from Sgr A^(*) and M87^(*) to set limitations on the BH parameters.
基金funded by the Research council of Norway,Equinor and Sekal with NFR(Grant No.308826).
文摘During drilling operations,cyclic loading is exerted on the wellbore wall by the vibrations of the drill string.This loading could lead to rock fatigue,which in turn might result in wellbore failure.In this study,a numerical model is developed to simulate the effects of repeated loading on rock fatigue and failure.The simulation is based on an elasto-plastic constitutive model coupled with a damage mechanics approach,which allows us to examine the wellbore instability due to drill string vibrations.The model is verified with the existing data in the literature related to experiments on impact of a steel ball against a curved wall.The findings indicate that cyclic loading increases the development of plastic strain around the wellbore significantly compared to static conditions,promoting rock fatigue.Furthermore,the cyclic loading expands the radius of the yielded zone substantially,a critical factor for maintaining wellbore integrity.The proposed model can be used to evaluate the wellbore stability under repetitive loading caused by the drill string action.
基金the support by grants from the NNSF of China with Grant Nos.12275264 and 12247103。
文摘This is a writeup of lectures delivered at the Asian Pacific Introductory School on Superstring and Related Topics in Beijing(2006)and an expanded version of these lectures given at the Third Summer School on Strings,Fields and Holography in Nanjing(2023).It aims to provide both a historical and pedagogical account of developments in finding 1/2 Bogomol?nyi–Prasad–Sommerfield(BPS)extended string solitons during the early stage of the so-called second string revolution,before which these objects were thought to be unrelated to strings.Nonsupersymmetric solutions related to brane/anti brane systems or non-BPS systems are also discussed.
基金supported by the National Natural Science Foundation of China(52174003,52374008).
文摘The complex vibration directly affects the dynamic safety of drill string in ultra-deep wells and extra-deep wells.It is important to understand the dynamic characteristics of drill string to ensure the safety of drill string.Due to the super slenderness ratio of drill string,strong nonlinearity implied in dynamic analysis and the complex load environment,dynamic simulation of drill string faces great challenges.At present,many simulation methods have been developed to analyze drill string dynamics,and node iteration method is one of them.The node iteration method has a unique advantage in dealing with the contact characteristics between drill string and borehole wall,but its drawback is that the calculation consumes a considerable amount of time.This paper presents a dynamic simulation method of drilling string in extra-deep well based on successive over-relaxation node iterative method(SOR node iteration method).Through theoretical analysis and numerical examples,the correctness and validity of this method were verified,and the dynamics characteristics of drill string in extra-deep wells were calculated and analyzed.The results demonstrate that,in contrast to the conventional node iteration method,the SOR node iteration method can increase the computational efficiency by 48.2%while achieving comparable results.And the whirl trajectory of the extra-deep well drill string is extremely complicated,the maximum rotational speed downhole is approximately twice the rotational speed on the ground.The dynamic torque increases rapidly at the position of the bottom stabilizer,and the lateral vibration in the middle and lower parts of drill string is relatively intense.
基金the Science and Technology Commission of Shanghai,No.18DZ1930309.
文摘BACKGROUND Traditional esophagogastroduodenoscopy(EGD),an invasive examination method,can cause discomfort and pain in patients.In contrast,magnetically controlled capsule endoscopy(MCE),a noninvasive method,is being applied for the detection of stomach and small intestinal diseases,but its application in treating esophageal diseases is not widespread.AIM To evaluate the safety and efficacy of detachable string MCE(ds-MCE)for the diagnosis of esophageal diseases.METHODS Fifty patients who had been diagnosed with esophageal diseases were pros-pectively recruited for this clinical study and underwent ds-MCE and conven-tional EGD.The primary endpoints included the sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy of ds-MCE for patients with esophageal diseases.The secondary endpoints consisted of visualizing the esophageal and dentate lines,as well as the subjects'tolerance of the procedure.RESULTS Using EGD as the gold standard,the sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy of ds-MCE for esophageal disease detection were 85.71%,86.21%,81.82%,89.29%,and 86%,respectively.ds-MCE was more comfortable and convenient than EGD was,with 80%of patients feeling that ds-MCE examination was very comfortable or comfortable and 50%of patients believing that detachable string v examination was very convenient.CONCLUSION This study revealed that ds-MCE has the same diagnostic effects as traditional EGD for esophageal diseases and is more comfortable and convenient than EGD,providing a novel noninvasive method for treating esophageal diseases.
基金supported by the Science and Technology Development aid Project of Xuzhou Science and Technology Bureau(KC21249)supported by Hainan Provincial Natural Science Foundation of China(824MS052)Scientific Research Startup Foundation of Hainan University.
文摘Objective:This study aims to explore the expression patterns of cysteine string protein alpha(CSPα)and cysteine string protein beta(CSPβ)in the mammalian inner ear,with an emphasis on their temporal dynamics during the developmental stages of C57BL/6 mice.Methods:We utilized immunofluorescence staining to assess the localization and distribution of CSPαand CSPβwithin the inner ears of C57BL/6 mice and miniature pigs.Additionally,this method facilitated the investigation of their temporal expression profiles.Results:In adult C57BL/6 mice and miniature pigs,CSPαand CSPβwere identified in the cytoplasm of inner hair cells and spiral ganglion cells,yet were absent in outer hair cells.Both proteins were found to colocalize with Ctbp2 on the basal side of the cytoplasm in inner hair cells’basilar membrane.Expression of CSPαwas observed at the nerve fiber termini at the basilar membrane’s base of inner and outer hair cells 10 days postnatally in C57BL/6 mice.Notably,expression of both CSPαand CSPβin the cytoplasm of inner hair cells emerged on the 12th day post-birth,aligning with the timeline for registering cochlear potentials.The expression levels of both proteins increased with age,but were consistently absent in outer hair cells.Contrastingly,expression of CSPαand CSPβwas present in the cytoplasm of inner hair cells in miniature pigs as early as one day post-birth,yet remained absent in the three rows of outer hair cells.Conclusion:CSPαand CSPβexhibit predominant and specific expression in inner hair cells and spiral ganglion cells.A unique expression pattern was observed for CSPα,which was also present at the nerve fiber endings of both inner and outer hair cells.The developmental expression trajectory of CSPαand CSPβin mouse inner hair cells is characterized by an initial absence,followed by a gradual increase.Moreover,the timing of expression onset between mice and miniature pigs indicates distinct temporal dynamics,suggesting a potential role in auditory development.
文摘Using real fields instead of complex ones, it is suggested here that the fermions are pairs of coupled strings with an internal tension. The interaction between the two coupled strings is due to an exchange mechanism which is proportional to Planck’s constant. This may be the result of two massless bosons (hypergluons) coupled by a preon (prequark) exchange. It also gives a physical explanation to the origin of the Planck constant, and origin of spin.
文摘A model for particles based on preons in chiral, vector and tensor/graviton supermultiplets of unbroken global supersymmetry is engineered. The framework of the model is little string theory. Phenomenological predictions are discussed.
文摘We compare, following Pati, global symmetries, our topological supersymmetric preon model with the heterotic E<sub>8</sub> × E<sub>8</sub> string theory. We include Pati’s supergravity based preon model in this work and compare the preon interactions of his model to ours. Based on preon-string symmetry comparison and preon phenomenological results, we conclude that the fundamental particles are likely preons rather than standard model particles. .
文摘Edward Witten has been described as“the most brilliant physicist of his generation”,and some even compare him to Isaac Newton.A deeply original and dedicated theoretical physicist,Witten's primary focus is string theory—a“theory of everything”that proposes the universe's fundamental components are curves,or“strings”arranged in loops.in loops.He has been a leading advocate and influential contributor in this field,famously stating,“It was very clear that if I didn't spend my life concentrating on string theory,I would simply be missing my life's calling.”
文摘为了研究复杂温压场下钻柱系统动力学特性,综合考虑了钻头-岩石相互作用,温度和压力对钻井液性能影响、温度对钻柱几何尺寸与特性影响以及钻柱系统所受轴向与扭转方向耦合振动,基于状态依赖时滞方法建立了4自由度直井钻柱系统动力学模型,分析了钻压(weight on bit,WOB)、驱动转速、钻井液密度以及地温梯度对系统动力学特性的影响。在此基础上,探究了WOB和驱动转速,钻井液密度和地温梯度对钻柱系统最小速度的影响规律。研究结果表明:增大钻压与钻井液密度会加剧钻柱系统振动程度,造成钻头黏滑振动;增加转速可以抑制黏滑振动;随着地温梯度的增加,会使钻头跳钻问题与黏滑振动更为严重;合理选择钻压与驱动转速能够避免黏滑振动,提高钻进效率;钻井液密度与地温梯度对钻柱系统的影响使得其最小速度呈现出一种非线性、无明显规律的特征,需要根据现场工况,结合模型进行参数优选。
