Understanding of the fast mediated bioelectrocatalytic reaction on microelectrodes based on an analytical formula

It is suggested that for some transition metal hexahalo complexes, the Eg-(a1g + eg) vibronic coupling model is better suited than the classical T2g-(a1g + eg) model. For the former, alternative model, the potential constants in the analytical formula are evaluated from the numerical map of the adiabatic potential surface by using the linear regression method. The numerical values for 29 hexahalo complexes of the 1st row transition metals are obtained by the CNDO/2 method. Some interesting trends of parameters of such Jahn-Teller-active systems are disclosed.

Download Full-text

Über den Mechanismus der Bildung von Polyanionen in wäßriger Lösung. Zum Bildungsmechanismus eines Polytetramolybdations [Mo4O144-]n / On the Mechanism of Formation of Polyanions in Aqueous Solution. Concerning the Mechanism of Formation of a Polytetramolybdate Ion [Mo4O144-]n

Zeitschrift für Naturforschung B ◽

10.1515/znb-1976-0607 ◽

1976 ◽

Vol 31 (6) ◽

pp. 737-748 ◽

Cited By ~ 5

Author(s):

Karl-Heinz Tytko

Keyword(s):

Aqueous Solution ◽

Coordination Sphere ◽

Analytical Formula ◽

Reaction Pathways ◽

Mechanism Of Formation ◽

X Ray ◽

Theoretical Considerations

Possible structures and the pertinent reaction pathways for the polymetalate ion present in a slightly soluble polymetalate having the analytical formula A2O · 2 MOs have been derived on the basis of theoretical considerations. Structure and kind of combination of the tetrameric units of one of the possibilities are in agreement with the results of X-ray structure analyses. First the previously proposed planar tetrametalate ion [M4O12(OH)4]4--is formed by stepwise aggregation according to an addition mechanism. This species undergoes a rearrangement of the coordination sphere of two of the M atoms and is then subject to a polycondensation resulting in a polytetrametalate chain, [M4O144-]n.

Download Full-text

An Improved Machine Learning-Based Employees Attrition Prediction Framework with Emphasis on Feature Selection

Mathematics ◽

10.3390/math9111226 ◽

2021 ◽

Vol 9 (11) ◽

pp. 1226

Author(s):

Saeed Najafi-Zangeneh ◽

Naser Shams-Gharneh ◽

Ali Arjomandi-Nezhad ◽

Sarfaraz Hashemkhani Zolfani

Keyword(s):

Machine Learning ◽

Feature Selection ◽

Standard Deviation ◽

Analytical Formula ◽

Feature Selection Method ◽

Selection Method ◽

Performance Measure ◽

Learning Approaches ◽

Training Costs ◽

Professional Employees

Companies always seek ways to make their professional employees stay with them to reduce extra recruiting and training costs. Predicting whether a particular employee may leave or not will help the company to make preventive decisions. Unlike physical systems, human resource problems cannot be described by a scientific-analytical formula. Therefore, machine learning approaches are the best tools for this aim. This paper presents a three-stage (pre-processing, processing, post-processing) framework for attrition prediction. An IBM HR dataset is chosen as the case study. Since there are several features in the dataset, the “max-out” feature selection method is proposed for dimension reduction in the pre-processing stage. This method is implemented for the IBM HR dataset. The coefficient of each feature in the logistic regression model shows the importance of the feature in attrition prediction. The results show improvement in the F1-score performance measure due to the “max-out” feature selection method. Finally, the validity of parameters is checked by training the model for multiple bootstrap datasets. Then, the average and standard deviation of parameters are analyzed to check the confidence value of the model’s parameters and their stability. The small standard deviation of parameters indicates that the model is stable and is more likely to generalize well.

Download Full-text

First-arrival traveltime inversion of seismic diving waves observed on undulant surface

Geophysical Journal International ◽

10.1093/gji/ggab025 ◽

2021 ◽

Vol 225 (2) ◽

pp. 1020-1031

Author(s):

Huachen Yang ◽

Jianzhong Zhang ◽

Kai Ren ◽

Changbo Wang

Keyword(s):

Turning Points ◽

Analytical Formula ◽

Velocity Model ◽

Western China ◽

Inversion Method ◽

Mountain Area ◽

Traveltime Inversion ◽

Static Correction ◽

Velocity Models ◽

First Arrival

SUMMARY A non-iterative first-arrival traveltime inversion method (NFTI) is proposed for building smooth velocity models using seismic diving waves observed on irregular surface. The new ray and traveltime equations of diving waves propagating in smooth media with undulant observation surface are deduced. According to the proposed ray and traveltime equations, an analytical formula for determining the location of the diving-wave turning points is then derived. Taking the influence of rough topography on first-arrival traveltimes into account, the new equations for calculating the velocities at turning points are established. Based on these equations, a method is proposed to construct subsurface velocity models from the observation surface downward to the bottom using the first-arrival traveltimes in common offset gathers. Tests on smooth velocity models with rugged topography verify the validity of the established equations, and the superiority of the proposed NFTI. The limitation of the proposed method is shown by an abruptly-varying velocity model example. Finally, the NFTI is applied to solve the static correction problem of the field seismic data acquired in a mountain area in the western China. The results confirm the effectivity of the proposed NFTI.

Download Full-text

Local modal participation analysis of nonlinear systems using Poincaré linearization

Nonlinear Dynamics ◽

10.1007/s11071-019-05363-1 ◽

2019 ◽

Vol 99 (1) ◽

pp. 803-811 ◽

Cited By ~ 2

Author(s):

Boumediene Hamzi ◽

Eyad H. Abed

Keyword(s):

Nonlinear Systems ◽

Autonomous Systems ◽

Analytical Formula ◽

Linear Case ◽

Local Mode ◽

Initial Condition ◽

Initial State ◽

State Participation ◽

Symmetry Assumption ◽

Definition Of

AbstractThe paper studies an extension to nonlinear systems of a recently proposed approach to the definition of modal participation factors. A definition is given for local mode-in-state participation factors for smooth nonlinear autonomous systems. While the definition is general, the resulting measures depend on the assumed uncertainty law governing the system initial condition, as in the linear case. The work follows Hashlamoun et al. (IEEE Trans Autom Control 54(7):1439–1449 2009) in taking a mathematical expectation (or set-theoretic average) of a modal contribution measure over an uncertain set of system initial state. Poincaré linearization is used to replace the nonlinear system with a locally equivalent linear system. It is found that under a symmetry assumption on the distribution of the initial state, the tractable calculation and analytical formula for mode-in-state participation factors found for the linear case persists to the nonlinear setting. This paper is dedicated to the memory of Professor Ali H. Nayfeh.

Download Full-text

Design of an Ultra-Wideband Microstrip-to-Slotline Transition on Low-Permittivity Substrate

Electronics ◽

10.3390/electronics9081329 ◽

2020 ◽

Vol 9 (8) ◽

pp. 1329

Author(s):

Jung Seok Lee ◽

Gwan Hui Lee ◽

Wahab Mohyuddin ◽

Hyun Chul Choi ◽

Kang Wook Kim

Keyword(s):

Microstrip Line ◽

Return Loss ◽

Analytical Formula ◽

Parameter Tuning ◽

Ultra Wideband ◽

Design Parameters ◽

Analytical Line ◽

Cross Sectional ◽

Analysis And Design ◽

Low Permittivity

Analysis and design of an ultra-wideband microstrip-to-slotline transition on a low permittivity substrate is presented. Cross-sectional structures along the proposed transition are analyzed using conformal mapping assuming quasi-TEM modes, attaining one analytical line impedance formula with varying design parameters. Although the slotline is a non-TEM transmission line, the transitional structures are configured to have quasi-TEM modes before forming into the slotline. The line impedance is optimally tapered using the Klopfenstein taper, and the electric field shapes are smoothly transformed from microstrip line to slotline. The analytical formula is accurate within 5% difference, and the final transition configuration can be designed without parameter tuning. The implemented microstrip-to-slotline transition possesses insertion loss of less than 1.5 dB per transition and return loss of more than 10 dB from 4.4 to over 40 GHz.

Download Full-text

Pre-Impact Configuration Designing of a Robot Manipulator for Impact Minimization

Journal of Mechanisms and Robotics ◽

10.1115/1.4035373 ◽

2017 ◽

Vol 9 (3) ◽

Cited By ~ 2

Author(s):

Jingchen Hu ◽

Tianshu Wang

Keyword(s):

Impact Force ◽

Robot Manipulator ◽

Analytical Formula ◽

Joint Space ◽

Collision Problem ◽

Spatial Operator ◽

Inertia Ellipsoid ◽

The Impact ◽

Maximum Minimum ◽

Simple Analytical Formula

This paper studies the collision problem of a robot manipulator and presents a method to minimize the impact force by pre-impact configuration designing. First, a general dynamic model of a robot manipulator capturing a target is established by spatial operator algebra (SOA) and a simple analytical formula of the impact force is obtained. Compared with former models proposed in literatures, this model has simpler form, wider range of applications, O(n) computation complexity, and the system Jacobian matrix can be provided as a production of the configuration matrix and the joint matrix. Second, this work utilizes the impulse ellipsoid to analyze the influence of the pre-impact configuration and the impact direction on the impact force. To illustrate the inertia message of each body in the joint space, a new concept of inertia quasi-ellipsoid (IQE) is introduced. We find that the impulse ellipsoid is constituted of the inertia ellipsoids of the robot manipulator and the target, while each inertia ellipsoid is composed of a series of inertia quasi-ellipsoids. When all inertia quasi-ellipsoids exhibit maximum (minimum) coupling, the impulse ellipsoid should be the flattest (roundest). Finally, this paper provides the analytical expression of the impulse ellipsoid, and the eigenvalues and eigenvectors are used as measurements to illustrate the size and direction of the impulse ellipsoid. With this measurement, the desired pre-impact configuration and the impact direction with minimum impact force can be easily solved. The validity and efficiency of this method are verified by a PUMA robot and a spatial robot.

Download Full-text

Effective Elastic Constants of Fiber-Eutectics and Transformation Particles Composite Ceramic

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.177.182 ◽

2010 ◽

Vol 177 ◽

pp. 182-185 ◽

Cited By ~ 5

Author(s):

Bao Feng Li ◽

Jian Zheng ◽

Xin Hua Ni ◽

Ying Chen Ma ◽

Jing Zhang

Keyword(s):

Elastic Modulus ◽

Elastic Constant ◽

Effective Stress ◽

Elastic Constants ◽

Transverse Isotropy ◽

Analytical Formula ◽

Composite Ceramic ◽

Phase Model ◽

Composite Ceramics ◽

Effective Elastic Constants

The composite ceramics is composed of fiber-eutectics, transformation particles and matrix particles. First, the recessive expression between the effective stress in fiber-eutectic and the flexibility increment tensor is obtained according to the four-phase model. Second, the analytical formula which contains elastic constant of the fiber-eutectic is obtained applying Taylor’s formula. The eutectic is transverse isotropy, so there are five elastic constants. Third, the effective elastic constants of composite ceramics are predicted. The result shows that the elastic modulus of composite ceramic is reduced with the increase of fibers fraction and fibers diameter.

Download Full-text

Analysis of Plastic-Zone Radius Influenced by Mechanical Parameters in Tunnel Excavation and Support

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.238.787 ◽

2012 ◽

Vol 238 ◽

pp. 787-790

Author(s):

Zhong Ming Su ◽

Rui Liu

Keyword(s):

Plastic Zone ◽

Axial Force ◽

Analytical Formula ◽

Mechanical Parameters ◽

Circular Tunnel ◽

Tunnel Excavation ◽

Dynamic Design ◽

Elastic Plastic ◽

Zone Radius ◽

Plastic Theory

According to the elastic-plastic theory, the analytical formula of plastic zone radius is established for circular tunnel in its excavation and support, and the effect of anchor support is verified based on the radius of plastic zone from the perspective of measured axial force. The influences to plastic zone by the variations of mechanical parameters and resistance of support are quantitatively analyzed. The result is of great significance to the monitoring measurement and the dynamic design and construction of tunnel.

Download Full-text