Level density of odd-A nuclei at saddle point

Based on the covariant density functional theory,by employing the core–quasiparticle coupling(CQC)model,the nuclear level density of odd-A nuclei at the saddle point is achieved.The total level density is calculated via the convolution of the intrinsic level density and the collective level density.The intrinsic level densities are obtained in the finite-temperature covariant density functional theory,which takes into account the nuclear deformation and pairing self-consistently.For saddle points on the free energy surface in the(β_(2),γ)plane,the entropy and the associated intrinsic level density are compared with those of the global minima.By introducing a quasiparticle to the two neighboring even–even core nuclei,whose properties are determined by the five-dimensional collective Hamiltonian model,the collective levels of the odd-A nuclei are obtained via the CQC model.The total level densities of the^(234-240)U agree well with the available experimental data and Hilaire’s result.Furthermore,the ratio of the total level densities at the saddle points to those at the global minima and the ratio of the total level densities to the intrinsic level densities are discussed separately.

Sensitivity analysis of factors affecting gravity dam anti-sliding stability along a foundation surface using Sobol method

The anti-sliding stability of a gravity dam along its foundation surface is a key problem in the design of gravity dams.In this study,a sensitivity analysis framework was proposed for investigating the factors affecting gravity dam anti-sliding stability along the foundation surface.According to the design specifications,the loads and factors affecting the stability of a gravity dam were comprehensively selected.Afterwards,the sensitivity of the factors was preliminarily analyzed using the Sobol method with Latin hypercube sampling.Then,the results of the sensitivity analysis were verified with those obtained using the Garson method.Finally,the effects of different sampling methods,probability distribution types of factor samples,and ranges of factor values on the analysis results were evaluated.A case study of a typical gravity dam in Yunnan Province of China showed that the dominant factors affecting the gravity dam anti-sliding stability were the anti-shear cohesion,upstream and downstream water levels,anti-shear friction coefficient,uplift pressure reduction coefficient,concrete density,and silt height.Choice of sampling methods showed no significant effect,but the probability distribution type and the range of factor values greatly affected the analysis results.Therefore,these two elements should be sufficiently considered to improve the reliability of the dam anti-sliding stability analysis.

Fiber optic monitoring of an anti-slide pile in a retrogressive landslide

Anti-slide piles are one of the most important reinforcement structures against landslides,and evalu-ating the working conditions is of great significance for landslide mitigation.The widely adopted analytical methods of pile internal forces include cantilever beam method and elastic foundation beam method.However,due to many assumptions involved in calculation,the analytical models cannot be fully applicable to complex site situations,e.g.landslides with multi-sliding surfaces and pile-soil interface separation as discussed herein.In view of this,the combination of distributed fiber optic sensing(DFOS)and strain-internal force conversion methods was proposed to evaluate the working conditions of an anti-sliding pile in a typical retrogressive landslide in the Three Gorges reservoir area,China.Brillouin optical time domain reflectometry(BOTDR)was utilized to monitor the strain distri-bution along the pile.Next,by analyzing the relative deformation between the pile and its adjacent inclinometer,the pile-soil interface separation was profiled.Finally,the internal forces of the anti-slide pile were derived based on the strain-internal force conversion method.According to the ratio of calculated internal forces to the design values,the working conditions of the anti-slide pile could be evaluated.The results demonstrated that the proposed method could reveal the deformation pattern of the anti-slide pile system,and can quantitatively evaluate its working conditions.

Spatial structural analysis of main saddle for single tower spatial cable self-anchored suspension bridge

Based on the engineering background of the Jiangxinzhou Bridge in Nanjing, issues related to the spatial main saddle of the self-anchored suspension bridge are studied. The refinement finite element model is established by the secondary development technology based on the platform of the general finite element program, and a reasonable load pattern is used in its spatial structural analysis, by which its path of force transference and stress distribution are obtained. Matched with the spatial main cable, the tangency point correction method is also discussed. The results show that the lateral wall stress of the saddle groove is higher than the stress within the wall due to the role of lateral forces in the finished bridge state; the horizontal volume force of the main cable can generate a gradient distributed vertical extrusion pressure on the saddle clamping device and the main saddle body; the geometric nonlinear effect of the self- anchored suspension bridge cable system in the construction process is significant, which can be reflected in the spatial tangent point position of the main cable with the main saddle changes a lot from free cable to finished cable.

Wind tunnel test for wind pressure characteristics on a saddle roof

The wind pressure characteristics on a saddle roof at wind direction along the connection of the low points are systematically studied by the wind tunnel test. First, the distributions of the mean and the fluctuating pressures on the saddle roof are provided. Through the wind pressure spectra, the process of generation, growth and break down of the vortex on the leading edge is presented from a microscopic aspect and then the distribution mechanism of the mean and fluctuating pressures along the vulnerable leading edge is explained. By analysis of the wind pressure spectra near the high points, it can be inferred that the body induced turbulence reflects itself as a high-frequency pressure fluctuation. Secondly, the third-and fourth-order statistical moments of the wind pressure are employed to identify the non-Gaussian nature of the pressure time history and to construct an easy tool to localize regions with a non-Gaussian feature. The cause of the non-Gaussian feature is discussed by virtue of the wind pressure spectra. It is concluded that the non-Gaussian feature of the wind pressure originates from the effects of flow separation and body-induced turbulence, and the former effect plays an obvious role.

Convergence analysis of the corrected Uzawa algorithm for symmetric saddle point problems

For the large sparse saddle point problems, Pan and Li recently proposed in [H. K. Pan, W. Li, Math. Numer. Sinica, 2009, 31（3）： 231-242] a corrected Uzawa algorithm based on a nonlinear Uzawa algorithm with two nonlinear approximate inverses, and gave the detailed convergence analysis. In this paper, we focus on the convergence analysis of this corrected Uzawa algorithm, some inaccuracies in [H. K. Pan, W. Li, Math. Numer. Sinica, 2009, 31（3）： 231-242] are pointed out, and a corrected convergence theorem is presented. A special case of this modified Uzawa algorithm is also discussed.

Kinematic Geometry for the Saddle Line Fitting of Planar Discrete Positions

The position synthesis of planar linkages is to locate the center point of the moving joint on a rigid link, whose trajectory is a circle or a straight line. Utilizing the min-max optimization scheme, the fitting curve needs to minimize the maximum fitting error to acquire the dimension of a planar binary P-R link. Based on the saddle point programming, the fitting straight line is determined to the planar discrete point-path traced by the point of the rigid body in planar motion. The property and evolution of the defined saddle line error can be revealed from three given separate points. A quartic algebraic equation relating the fitting error and the coordinates is derived, which agrees with the classical theory. The effect of the fourth point is discussed in three cases through the constraint equations. The multi-position saddle line error is obtained by combination and comparison from the saddle point programming. Several examples are presented to illustrate the solution process for the saddle line error of the moving plane. The saddle line error surface and the contour map presented to show the variations of the fitting error in the fixed frame. The discrete kinematic geometry is then set up to disclose the relations of the separate positions of the rigid body, the location of the tracing point on the moving body, and the position and orientation of the saddle line to the point-path. This paper presents a new analytic geometry method for saddle line fitting and provides a theoretical foundation for position synthesis.

Dynamic modeling and parameter identification of a gun saddle ring

In this study,a theoretical nonlinear dynamic model was established for a saddle ring based on a dynamic force analysis of the launching process and the structure according to contact-impact theory.The ADAMS software was used to build a parameterized dynamic model of the saddle ring.A parameter identification method for the ring was proposed based on the particle swarm optimization algorithm.A loading test was designed and performed several times at different elevation angles.The response histories of the saddle ring with different loads were then obtained.The parameters of the saddle ring dynamic model were identified from statistics generated at a 500 elevation angle to verify the feasibility and accuracy of the proposed method.The actual loading history of the ring at a 70°elevation angle was taken as the model input.The response histories of the ring under these working conditions were obtained through a simulation.The simulation results agreed with the actual response.Thus,the effectiveness and applicability of the proposed dynamic model were verified,and it provides an effective method for modeling saddle rings.

Saddle-Dolomite-Bearing Fracture Fillings and Records of Hot Brine Activity in the Jialingjiang Formation,Libixia Section,Hechuan Area of Chongqing City

Most vein minerals deposited in fractures of the Jialingjiang Formation from Libixia section, Hechan area include a large amount of saddle dolomite and accompanying celestite, calcite and fluorite. This study analyzed the nature, source, evolution of the fluids by plane-light petrography, fluid-inclusion methods, cathodoluminescence images, and stable isotopic compositions. The homogenization temperatures of two-phase aqueous fluid inclusions in dolomite range between 100 and 270℃. Combined with the jlSO data, it is suggested that the fluid responsible for the precipitation of fracture fillings have δ18O values between 10%o and 18‰ （relative to SMOW）. The saddle dolomite and the accompanying minerals were the result of activity of dense brines at elevated temperatures. Moreover, analysis shows that the fluid was derived from a mixture of marine-derived brine and deeper circulating flow. This fluid was enriched in Sr during diagenesis and formed celestite in fracture and for regional mineralization. Dissolution of saddle dolomite was attributed to the cooling of Mg/Ca-decreased fluids, which may relate to a leaching of gypsum to celestite in surrounding carbonates.

Coherence-Resonance-Induced Neuronal Firing near a Saddle-Node and Homoclinic Bifurcation Corresponding to Type-I Excitability

Excitability is an essential characteristic of excitable media such as nervous and cardiac systems.Different types of neuronal excitability are related to different bifurcation structures.We simulate the coherence resonance effect near a saddle-node and homoclinic bifurcation corresponding to type-I excitability in a theoretical neuron model,and recognize the obvious features of the corresponding firing pattern.Similar firing patterns are discovered in rat hippocampal CA1 pyramidal neurons.The results are not only helpful for understanding the dynamics of the saddle-node bifurcation and type-I excitability in a realistic nervous system,but also provide a practical indicator to identify types of excitability and bifurcation.

Thermal Fission Rate Calculated Numerically by Particles Multi-passing over SaddlePoint

Langevin simulation of the particles multi-passing over the saddle point is proposed to calculate thermal fission rate. Due to finite friction and the corresponding thermal fluctuation, a backstreaming exists in the process of the particle descent from the saddle to the scission. This leads to that the diffusion behind the saddle point has influence upon the stationary flow across the saddle point. A dynamical correction factor, as a ratio of the flows of multi- and first-overpassing the saddle point, is evaluated analytically. The results show that the fission rate calculated by the particles multi-passing over the saddle point is lower than the one calculated by the particle firstly passing over the saddle point, and the former approaches the results at the scission point.

Coincidence Point Theorems,Intersection Theorems and Saddle Point Theorems on FC-spaces

In this paper, we first give the definitions of finitely continuous topological space and FC-subspace generated by some set, and obtain coincidence point theorem, whole intersection theorems and Ky Fan type matching theorems, and finally discuss the existence of saddle point as an application of coincidence point theorem.

HESSIAN MATRIX BASED SADDLE POINT DETECTION FOR GRANULES SEGMENTATION IN 2D IMAGE

Segmenting the touching objects in an image has been remaining as a hot subject due to the problematic complexities, and a vast number of algorithms designed to tackle this issue have come into being since a decade ago. In this paper, a new granule segmentation algorithm is developed using saddle point as the cutting point. The image is binarized and then sequentially eroded to form a gray-scale topographic counterpart, followed by using Hessian matrix computation to search for the saddle point. The segmentation is performed by cutting through the saddle point and along the maximal gradient path on the topographic surface. The results of the algorithm test on the given real images indicate certain superiorities in both the segmenting robustness and execution time to the referenced methods.

Pre-Stressed Rope Reinforced Anti-Sliding Pile

Pre-stressed rope reinforced anti-sliding pile is a composite anti-sliding structure. It is made up of pre-stressed rope and general anti-sliding pile. It can bring traditional anti-sliding pile＇s retaining performance into full play, and to treat with landslide fast and economically. The difference between them is that the pre-stressed rope will transfix the whole anti- sliding pile through a prearranged pipe in this structure. The working mechanics, the design method and economic benefit are studied. The results show that the pre-stressed rope reinforced anti-sliding pile can treat with the small and middle landslides or high slopes well and possess the notable advantage of technology and economic.

The Formula of Generalized Center-Weak Saddle

In this paper, a problem of center-weak focus of a general system of degree n is transformed into a problem of generalized center-weak saddle. It offers: (1) the calculating formula of the saddle values of the former 4 orders in the general system of degree three; (2) some calculating formulae of the saddle values in the general homogeneous system of degree n.The problem of center-focus(saddle) plays an important role in the qualitative theory of ordinary differential equations. However, since the calculations are difficult, the results have not been satisfactory. On the basis of the author's work, Northeast. Math. J., 13(4)(1997), 487-494, the paper offers some calculating formulae of the saddle values.

Mixed Saddle Point and Its Equivalence with an Efficient Solution under Generalized (V, <i>p</i>)-Invexity

The purpose of this paper is to define the concept of mixed saddle point for a vector-valued Lagrangian of the non-smooth multiobjective vector-valued constrained optimization problem and establish the equivalence of the mixed saddle point and an efficient solution under generalized (V, p)-invexity assumptions.

Distributed Resource Allocation via Accelerated Saddle Point Dynamics

In this paper,accelerated saddle point dynamics is proposed for distributed resource allocation over a multi-agent network,which enables a hyper-exponential convergence rate.Specifically,an inertial fast-slow dynamical system with vanishing damping is introduced,based on which the distributed saddle point algorithm is designed.The dual variables are updated in two time scales,i.e.,the fast manifold and the slow manifold.In the fast manifold,the consensus of the Lagrangian multipliers and the tracking of the constraints are pursued by the consensus protocol.In the slow manifold,the updating of the Lagrangian multipliers is accelerated by inertial terms.Hyper-exponential stability is defined to characterize a faster convergence of our proposed algorithm in comparison with conventional primal-dual algorithms for distributed resource allocation.The simulation of the application in the energy dispatch problem verifies the result,which demonstrates the fast convergence of the proposed saddle point dynamics.

An Effective Numerical Procedure to Determine Saddle-Type Unstable Invariant Limit Sets in Nonlinear Systems

A new technique that can efficiently approximate the attracting set of a nonlinear dynamical system is proposed under the framework of point mapping with the cell reference method.With the aid of the approximated attracting set,the difficulties encountered by the PIM-triple method and bisection procedure in finding trajectories on the stable manifolds of chaotic saddles in basins of attraction and on basin boundaries can be overcome well.On the basis of this development,an effective method to determine saddle-type invariant limit sets of nonlinear dynamical systems can be devised.Examples are presented for the purposes of illustration and to demonstrate the capabilities of the proposed method.

Application of strength reduction method to dynamic anti-sliding stability analysis of high gravity dam with complex dam foundation

Considering that there are some limitations in analyzing the anti-sliding seismic stability of dam-foundation systems with the traditional pseudo-static method and response spectrum method, the dynamic strength reduction method was used to study the deep anti-sliding stability of a high gravity dam with a complex dam foundation in response to strong earthquake-induced ground action. Based on static anti-sliding stability analysis of the dam foundation undertaken by decreasing the shear strength parameters of the rock mass in equal proportion, the seismic time history analysis was carried out. The proposed instability criterion for the dynamic strength reduction method was that the peak values of dynamic displacements and plastic strain energy change suddenly with the increase of the strength reduction factor. The elasto-plastic behavior of the dam foundation was idealized using the Drucker-Prager yield criterion based on the associated flow rule assumption. The result of elasto-plastic time history analysis of an overflow dam monolith based on the dynamic strength reduction method was compared with that of the dynamic linear elastic analysis, and the reliability of elasto-plastic time history analysis was confirmed. The results also show that the safety factors of the dam-foundation system in the static and dynamic cases are 3.25 and 3.0, respectively, and that the F2 fault has a significant influence on the anti-sliding stability of the high gravity dam. It is also concluded that the proposed instability criterion for the dynamic strength reduction method is feasible.

Study for reasonable value of friction coefficient between main cable and saddle

The value of friction coefficient between the main cable and saddle, relates to not only the anti-slippage stability of three-tower suspension bridge, but also the reasonable stiffness of the middle tower and the magnitude of rigidity of the whole bridge. First, the paper does some comparative studies about the relevant provisions of international norms, and then, summarizes the relevant load test results both at home and abroad. Finally, the paper draws the appropriate anti-slippage safety factor for the most unfavorable load in accordance with international load standards, and discusses the rationality and feasibility of the friction coefficient of 0.2 between main cable and saddle.