Static softening behaviors of 7055 alloy during the interval time of multi-pass hot compression

Multipass plain strain compression test of 7055 alloy was carried out on Gleeble 1500D thermomechanical simulator to study the effect of interval time on static softening behavior between two passes. Microstructural features of the alloy deformed with delay times varying from 0 to 180 s after achieving a reduction of ,-~52 % in the 13 stages was investigated through TEM and EBSD observations. The 14th pass of peak stresses after different delay times were gained. The peak stress decreases with the interstage delay time increasing, but the decreasing trend is gradually slower. Static recovery, metadynamic recrystallization, and/or static recrystallization can be found in the alloy during two passes. The recovery and recrystallization degree increases with longer interstage delay time. The static recovery is the main softening mechanism. Subgrain coalescence and subgrain growth together with particle-stimulated nucleation are the main nucleation mechanisms for static recrystallization.

THE INFLUENCE OF ELECTRO-ACUPUNCTURE AT NEIGUAN AND FIVE SHU POINTS OF TWELVE REGULAR MERIDIANS AT DIFFERENT TIME ON SYSTOLIC TIME INTERVAL OF NORMAL YOUNG ADULTS

The influence of electro-acupuncture at Neiguan (PC 6)and five shu points of twelve regular meridians at different time on systolic time interval (ST I) of normal young adultswere studied with 6×6 Latin square design in this work.In 12 groups according to 12 regular merldlans,the STIs were measured respectively just before and after electro-acupuncture on Neiguan andfive shu points at 00:00,04:00,08:00,12:00,16:00 and 20:00 of a day.It was found thatexcept the PEPI and PEPI/LVETI ratio among Shenmen(HT 7),Shaochong(HT 9)and Neiguan,Guanchong(TE)and Yemen(TE 2)points,the effects of electro-acupuncture at Neiguan pointand five shu points of twelve regular meridians on the indices of STI of normal young adults wereshowing no slgnificant differences.There also was no difference in different sex.But the indices ofSTI were changed when electroacupuncture on the different points of different meridians at differenttime.

Association between tear film break up time and blink interval in visual display terminal users

AIM：To investigate the association between tear film break up time（TBUT）and blinking interval in visual display terminal（VDT）users.METHODS：Nine hundred and thirty VDT users underwent dry eye testing,and functional visual acuity（FVA）test.The blinking interval during FVA was compared with TBUT.Subjects with longer blinking interval than TBUT were considered as unstable tear film.Logistic regression analysis revealed the risk factors for unstable tear group.RESULTS：Among 930 workers,858 subjects（92.3%）participated in this study.Almost 80% of the subjects were categorized into the unstable tear group.Unstable tear group has significantly lower Schirmer values and TBUT（17.5±11.6 vs 21.1±11.5 mm,3.7±2.6 vs 5.7±2.7s,both P〈0.001）.There were no significant differences in epithelial staining or severity of symptoms.Logistic regression showed that over 40y was a risk for being unstable tear group[odds ratio（OR）=1.53;95%confidence interval（CI）=1.06-2.20].Contact lens use was protective factor for being in the unstable tear group（OR=0.37;95%CI=0.26-0.53）.CONCLUSION：Subjects with shorter TBUT than blinking interval are prevalent among VDT users.Subjects over the age of 40 shows an increased risk for unstable tear film.

Vitreoretinal surgeons'experience and time interval from pars-plana vitrectomy to cataract extraction

AIM:To identify the association of the vitreoretinal surgeons'experience with the time interval between parsplana vitrectomy(PPV)and cataract extraction(CE).METHODS:Eyes with prior PPV and following CE were included in this retrospective cohort study.The years of practice and the annual case volume were used to describe the surgeons'experience.Multivariable linear regression analysis was used to investigate the relationship between surgeons'experience and the time interval adjusted for the patients age,gender,intraocular tamponade,and case complexity.RESULTS:Of 132430 eyes,1445 eyes were included in this study.In multivariable linear regression analysis,cases performed by surgeons with>20 practice years had longer time intervals compared with surgeons with<10 practice years after adjusted for other variables(β=0.329,95%CI:0.113 to 0.549,P=0.003).No difference in time interval was detected for comparing the lowest with the highest volume groups(β=0.089,95%CI:-0.164 to 0.343,P=0.343).The surgeons'practice years were not directly with the volume.For complicated surgery,the higherpractice-year surgeons had longer time interval than lowerpractice-year surgeons.CONCLUSION:The time intervals from PPV to CE is longer in higher-practice-year surgeons.The surgeons'practice years may have a greater effect on the time interval than annual case volume in high-complexity cases.Matching the complexity of vitreoretinal diseases with the surgeons'practice year should be considered.

Time variant multi-objective linear fractional interval-valued transportation problem

This paper studies a time-variant multi-objective linear fractional transportation problem. In reality, transported goods should reach in destinations within a specific time. Considering the importance of time, a time-variant multi-objective linear fractional transportation problem is formulated here. We take into account the parameters as cost, supply and demand are interval valued that involved in the proposed model, so we treat the model as a multi-objective linear fractional interval transportation problem. To solve the formulated model, we first convert it into a deterministic form using a new transformation technique and then apply fuzzy programming to solve it. The applicability of our proposed method is shown by considering two numerical examples. At last, conclusions and future research directions regarding our study is included.

Variational Inference Based Kernel Dynamic Bayesian Networks for Construction of Prediction Intervals for Industrial Time Series With Incomplete Input

Prediction intervals(PIs)for industrial time series can provide useful guidance for workers.Given that the failure of industrial sensors may cause the missing point in inputs,the existing kernel dynamic Bayesian networks(KDBN),serving as an effective method for PIs construction,suffer from high computational load using the stochastic algorithm for inference.This study proposes a variational inference method for the KDBN for the purpose of fast inference,which avoids the timeconsuming stochastic sampling.The proposed algorithm contains two stages.The first stage involves the inference of the missing inputs by using a local linearization based variational inference,and based on the computed posterior distributions over the missing inputs the second stage sees a Gaussian approximation for probability over the nodes in future time slices.To verify the effectiveness of the proposed method,a synthetic dataset and a practical dataset of generation flow of blast furnace gas(BFG)are employed with different ratios of missing inputs.The experimental results indicate that the proposed method can provide reliable PIs for the generation flow of BFG and it exhibits shorter computing time than the stochastic based one.

Stationarity Intervals of Time-Variant Channel in High Speed Railway Scenario

The non-stationary behavior, caused by the train movement, is the main factor for the variation of high speed railway channel. To measure the time-variant effect, the parameter of stationarity interval, in which the channel keeps constant or has no great change, is adopted based on Zhengzhou-Xi'an (Zhengxi) passenger dedicated line measurement with different train speeds. The stationarity interval is calculated through the definition of Local Region of Stationarity (LRS) under three train velocities. Furthermore, the time non-stationary characteristic of high speed railway channel is compared with five standard Multiple-Input Multiple-Output (MIMO) channel models, i.e. Spatial Channel Model (SCM), extended version of SCM (SCME), Wireless World Initiative New Radio Phase II (WINNERII), International Mobile Telecommunications-Advanced (IMT-Advanced) and WiMAX models which contain the high speed moving scenario. The stationarity interval of real channel is 9 ms in 80% of the cases, which is shorter than those of the standard models. Hence the real channel of high speed railway changes more rapidly. The stationarity intervals of standard models are different due to different modeling methods and scenario definitions. And the compared results are instructive for wireless system design in high speed railway.

Influences of different time intervals between loop electrosurgical excision and abdominal hysterectomy or radical hysterectomy on postoperative complications: a retrospective analysis

Objective:To study the influences of different time intervals between loop electrosurgical excision (LEEP) and abdominal hysterectomy or radical hysterectomy on postoperative complications. Methods:Sixty-eight patients, who received subsequent abdominal hysterectomy or radical hysterectomy after LEEP due to CIN Ⅲ and cervical cancer (IA1, IA2 and IB1), were included in the present study. The hospital and clinic records of these patients were reviewed. The patients were divided into three groups according to the time intervals between LEEP and hysterectomy or radical hysterectomy: group 1(within 48 h), group 2 (between 48 h to 6 weeks), and group 3(> 6 weeks ).Results: General characteristics of patients, including the mean age, delivery history, BMI, menopausal status, clinical stage and HPV infection, were comparable between patients of different groups. There were no significant differences in the mean transfusion amount, posthysterectomy hospital stay or operation time between different groups. The frequencies and spectrum of complications were not significantly affected by the time interval between LEEP and hysterectomy or radical hysterectomy. Conclusion: It is concluded that whenever the LEEP is done, the operation including hysterectomy or radical hysterectomy can be conducted at any time as it is necessary for the patients.

Study on conveyor natural frequency and time intervalfor switching off resistances

A conveyor belt driven by wound rotor motors produces dynamic tension, velocity and accelerationduring starting. The terrible situation (such as resonance) in dynamic analysis and design is that system naturalfrequencies are equal to those for switching off electric resistances. This paper analyzes and determines systemnatural frequencies based on a modeling method of receptances with the analysis of sub-systems model and of theprinciple of their addition and conveyor loop closure. It also puts forward to calculate the time interval for switching off electric resistances. The starting of one conveyor is simulated by lumped-mass-spring-model software tofurther illustrate the influence of time interval for switching off electric resistances on conveyor dynamic behavior. Two methods are also compared. The receptance model is proved to be an excellent alternative.

On designing memory state feedback controller for linear systems with interval time-varying delay

This paper is concerned with the design of a memory state feedback controller for linear systems with interval time-varying delays.The time delay is assumed to be a time-varying continuous function belonging to a given interval,which means that the lower and upper bounds of time-varying delay are available.First,a less conservative delay-range-dependent stability criteria is proposed by using a new interval fraction method.In the process of controller synthesis,the history information of system is considered in the controller design by introducing the lower delay state.Moreover,the usual memoryless state feedback controller for the underlying systems could be considered as a special case of the memory case.Finally,two numerical examples are given to show the effectiveness of the proposed method.

Timed automata for metric interval temporal logic formulae in prototype verification system

Based on analysis of the syntax structure and semantics model of the metric interval temporal logic （MITL） formulas, it is shown how to transform a formula written in the real-time temporal logic MITL formula into a fair timed automaton （TA） that recognizes its satisfying models with prototype verification system （PVS） in this paper. Both the tabular construction＇s principles and the PVS implementation details are given for the different type of MITL formula according to the corresponding semantics interpretations. After this transformation procedure, specifications expressed with MITL formula can be verified formally in the timed automata framework developed previously.

An On-Line Modeling Based Kalman Filtering Process for Time-Interval-Variable Sequences with Application to Astronomic Surveying

The problem of variable sampling time interval which appears in application of Kalman Filtering is analyzed and the corresponding filtering process with or without present transition matrix is suggested, then an application experiment for astronomical surveying is introduced. In this process, the known stochastically variable sampling time intervals play the roles as deterministic input sequences of the state-space description, and the corresponding matrix and (if needed) state transition matrix can be established by performing real-time and structure-linear system identification.

Discussion of the Horizontal Intensity of Late Quaternary Fault Activity Along the Tianjingshan Fault Zone in Different Time Intervals and Fault Segments

By computing and classifying the data of gully offset obtained from field surveys along the Tianjingshan fault zone and estimating the ages of three types of gullies,the strike-slip rates along the fault zone are discussed in different time intervals and fault segments.The results suggest that the intensity of activity along the fault zone is not strong,but the differences between different time intervals and fault segments since the late Pleistocene have been obvious.The average rates range from 0.23 mm/a to 1.62 mm/a.The largest average rate is 1.40 mm/a,which occurred in the early and middle of late Pleistocene along the western segment of the fault zone.Since the late stage of the late Pleistocene,the center of faulting activity of the fault zone has shifted to the middle segment,and the average slip rates range have changed from 1.30 mm/a to 1.63 mm/a.

Time Intervals of the Electron Transitions between the Energy States in the Hydrogen Atom Calculated in a Non-Probabilistic Way

Definitions of the mechanical parameters entering the Bohr model of the hydrogen atom allowed us to calculate the time intervals connected with the electron transitions between the nearest-neighbouring energy levels in the atom. This is done in a strictly non-probabilistic way. The time results are compared with those derived earlier on the basis of the classical Joule-Lenz law for the energy emission adapted to the case of the electron transfer in the quantum systems. A similar formalism has been next applied to the harmonic oscillator and a particle moving in the one-dimensional potential box.

Passivity analysis for uncertain stochastic neural networks with discrete interval and distributed time-varying delays

The problem of passivity analysis is investigated for uncertain stochastic neural networks with discrete interval and distributed time-varying delays.The parameter uncertainties are assumed to be norm bounded and the delay is assumed to be time-varying and belongs to a given interval,which means that the lower and upper bounds of interval time-varying delays are available.By constructing proper Lyapunov-Krasovskii functional and employing a combination of the free-weighting matrix method and stochastic analysis technique,new delay-dependent passivity conditions are derived in terms of linear matrix inequalities（LMIs）.Finally,numerical examples are given to show the less conservatism of the proposed conditions.

Delay-dependent robust exponential stabilization for uncertain systems with interval time-varying delays

New robust exponential stabilization criteria for interval time-varying delay systems with norm-bounded uncertainties are proposed. Based on the free-weighting matrices and new Lyapunov-Krasovskii functionals, such criteria are obtained by dealing with system model directly and designing memoryless state feedback controllers and expressed in terms of linear matrix inequalities （LMIs）. Moreover, the criteria are applicable to the case whether the derivative of the time-varying delay is bounded or not. The state decay rate is estimated by the corresponding LMIs. Numerical examples are given to illustrate the effectiveness of the proposed method.

Robust Stability Criteria for Neutral Systems with Interval Time-Varying Delays and Nonlinear Perturbations

This paper investigates the problem of delay-dependent robust stability analysis for a class of neutral systems with interval time-varying delays and nonlinear perturbations. Such nonlinear perturbations are with time-varying but norm-bounded characteristics. Based on a new Lyapunov-Krasovskii functional together with a free-weighting matrices technique,improved delay-dependent stability criteria are established. It is shown that less conservative results can be obtained in terms of linear matrix inequalities( LMIs). Numerical examples are provided to demonstrate the effectiveness and less conservatism of the proposed approach.

TIME INTERVAL APPROACH TO THE PULSED NEUTRON LOGGING METHOD

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