震损RC框架结构减震加固的可修性研究

如何快速判定震损建筑可修与否是震后抗震鉴定与应急修复加固工作的重要环节。以震损RC框架结构减震加固为研究内容,分析减震加固的基本原理,并基于反应谱理论探讨等效周期、等效阻尼比与反应谱参数之间的定量关系。同时,从安全性与经济性角度出发,初步确定震损RC框架结构的可修指标及采用消能减震加固技术的可修范围,给出实际工程中实施可修性评价的不同途径,藉此期望能为震后RC框架结构减震加固工作提供一定的参考依据。

GO法分析C3列控车载系统可靠性的改进

针对传统GO法在分析具有共因失效、冷备等特征的可修系统可靠性时存在的不足,增设热储备门和冷储备门两个新操作符,给出其定量计算公式.基于改进的GO法并考虑C3列控系统的可维修性、共因失效、冗余等特征,在维修人员充足的条件下分析了其可靠性.研究表明:共因失效是可修系统可靠性分析的重要因素,不能忽略;与动态故障树法相比,GO法在可修系统可靠性分析中的效率更高,在空间和时间上优势更明显.

损失分布和非结构损失对房屋建筑地易损性的影响

房屋建筑的地震易损性是地震损失评估和地震巨灾风险模型的基础。作为房屋建筑的重要组成部分,各类非结构构件的损失在现有的易损性模型中并未得到足够重视。本文以一栋典型钢筋混凝土框架结构教学楼为对象,通过将房屋建筑中的各类构件划分为具有不同地震损伤特性和损失后果的易损性组,考察建筑内的损失分布和非结构损失对房屋建筑地震易损性的影响。分析结果表明:由于许多非结构构件在中小地震作用下即可能发生较严重的破坏,房屋建筑在中小地震下的易损性主要受非结构损失控制;随着地震动强度等级的不断提高,结构损伤渐趋严重,结构损失对整体建筑易损性的影响不断增大;在结构进入震后不可修状态之前,建筑不同楼层的损失分布是评估建筑地震损失时不可忽略的因素。

医疗设备选购与维修

医疗设备的性能、质量、先进性、实用性 ,制约着现代医疗的发展。努力提高医疗设备的投资效率、技术效率 ,确保设备可靠、可修 ,降低故障率 ,延长使用寿命是医疗设备维修与管理的重要内容。

Evaluation of Blast-Resistant Performance Predicted by Damaged Plasticity Model for Concrete

in order to evaluate the capacity of reinforced concrete （RC） structures subjected to blast Ioadings, the damaged plasticity model for concrete was used in the analysis of the dynamic responses of blast-loaded RC structures, and all three failure modes were numerically simulated by the finite element software ABAQUS. Simulation results agree with the experimental observations. It is demonstrated that the damaged plasticity model for concrete in the finite element software ABAQUS can predict dynamic responses and typical flexure, flexure-shear and direct shear failure modes of the blast-loaded RC structures.

Reliability Analysis of Repairable Systems Using Stochastic Point Processes

In order to analyze the failure data from repairable systems, the homogeneous Poisson process (HPP) is usually used. In general, HPP cannot be applied to analyze the entire life cycle of a complex, re-pairable system because the rate of occurrence of failures (ROCOF) of the system changes over time rather than remains stable. However, from a practical point of view, it is always preferred to apply the simplest method to address problems and to obtain useful practical results. Therefore, we attempted to use the HPP model to analyze the failure data from real repairable systems. A graphic method and the Laplace test were also used in the analysis. Results of numerical applications show that the HPP model may be a useful tool for the entire life cycle of repairable systems.

Reliability and maintainability analysis of electrical system of drum shearers

The reliability and maintainability of electrical system of drum shearer at Parvade. 1 Coal Mine in central Iran was analyzed. The maintenance and failure data were collected during 19 months of shearer operation. According to trend and serial correlation tests, the data were independent and identically distributed （iid） and therefore the statistical techniques were used for modeling. The data analysis show that the time between failures （TBF） and time to repair （TTR） data obey the lognormal and Weibull 3 parameters distribution respectively. Reliability-based preventive maintenance time intervals for electrical system of the drum shearer were calculated with regard to reliability plot. The reliability-based maintenance intervals for 90%, 80%, 70% and 50% reliability level are respectively 9.91, 17.96, 27.56 and 56.1 h. Also the calculations show that time to repair （TTR） of this system varies in range 0.17-4 h with 1.002 h as mean time to repair （MTTR）. There is a 80% chance that the electrical system of shearer of Parvade. 1 mine repair will be accomplished within 1.45 h.

Development of gold catalysts supported by unreducible materials:Design and promotions

Gold catalysis had been considered a highly efficient candidate for heterogeneous catalysis.It is well established that reducible-material-supported Au NPs are more reactive than the unreducible materials,unless specific modifications are carried out.However,unreducible materials such as carbon materials,silica,and alumina have particular advantages,including the easily controlled surface property,adjustable microscopic structure,earth-abundant reserves,and facile industrial manufacture.New strategies,influences,and mechanisms of modification to enhance the catalytic performance and thermal stability of unreducible-material-supported gold catalysts are among the most attractive research topics in gold catalysis.However,to the best of our knowledge,reports and reviews focused on unreducible-material-supported gold catalysts are lacking.Herein,the above concept will be thoroughly discussed regarding several typical unreducible supports,including the commonly used silica,alumina,carbon materials,and hydroxyapatite.The currently prevailing modification strategies will be summarized in detail from the aspects of theoretical conceptualization and practical methodology,including the ingenious synthesis method for catalyst with a specific structure,the currently prosperous electrostatic adsorption,colloid immobilization,and the applicative thermal gaseous treatment.The influences of physical and chemical modifications on the surface chemistry,electronic structure,interaction/synergy between Au-support/promoter,catalyst morphology and water precipitation will be also summarized.It is assumed that the review will shed light on significant studies on unreducible support in gold catalysis with the purpose of catalytic promotion and the promotion of the potential industrial demands in advance.Furthermore,the review will provide new insights into unreducible supports that can be potentially applied in gold catalysis.

Feasibility and reliability of the revised Edmonton Symptom Assessment System(ESAS-r)in Egyptian patients with advanced cancer:A single institutional experience

Objective This study aims to test the acceptance, feasibility, and usefulness of the Arabic version of the revised Edmonton Symptom AssesSment System （ESAS-r） among Egyptian patients with advanced cancer and to compare the rates of symptoms documented by patients and physicians. Methods Between August 2014 and February 2015, a total of 140 patients at Ain Shams University Hospitals in Cairo, Egypt received the Arabic version of the ESAS-r. For each patient, the ESAS-r was completed twice, first by the treating physician （as part of the basic assessment） and a second time by the patient, with a maximum of 2 hours between the two assessments. An additional survey was included to assess patients＇ acceptance of the survey and their preferences. Results Out of 140 enrolled patients in the study, 11 patients refused to complete the questionnaire, and 10 patients were excluded due to incomplete records in their medical records. Complete data was retrieved for 119 patients who were included for further analyses. The 78 （65%） patients declared that the test was clear and easy to complete. They were able to answer the test without help. Collectively, tiredness and sense of well-being were the most commonly encountered symptoms in ratings obtained by both patients and physicians. Tiredness was the only symptom showing a significant difference between the two rating methods, patient-rated scores being higher （P = 0.032）. Cronbach＇s alpha showed that both tests com- pleted by the physician and the patients were internally consistent： the physician-rated test had a coefficient of 0.877, and the patient-rated test had a coefficient of 0.863. All ESAS scores had good internal consis- tency, with a Cmnbach＇s alpha coefficient of 0.88. The internal consistency remained high after removal of individual symptom scores, with Cronbach＇s alpha coefficients ranging from 0.823 to 0.902, indicating that no individual question had undue influence on the total ESAS score. Conclusion The ESAS-r was easily understood by and applicable to patients. There was no significant discrepancy in the rates of symptoms reported by the patients and physicians, apart from tiredness. Based on this, the test could be applied on a larger scale with in-home patients. This test can be cost-effective and can decrease the number of hospital visits among advanced cancer patients in need of supportive treat- ment rather than active cancer therapy.

Multi-component opportunistic maintenance optimization for wind turbines with consideration of seasonal factor

Aiming at wind turbines,the opportunistic maintenance optimization is carried out for multi-component system,where minimal repair,imperfect repair,replacement as well as their effects on component’s effective age are considered.At each inspection point,appropriate maintenance mode is selected according to the component’s effective age and its maintenance threshold.To utilize the maintenance opportunities for the components among the wind turbines,opportunistic maintenance approach is adopted.Meanwhile,the influence of seasonal factor on the component’s failure rate and improvement factor’s decrease with the increase of repair’s times are also taken into account.The maintenance threshold is set as the decision variable,and an opportunistic maintenance optimization model is proposed to minimize wind turbine’s life-cycle maintenance cost.Moreover,genetic algorithm is adopted to solve the model,and the effectiveness is verified with a case study.The results show that based on the component’s inherent reliability and maintainability,the proposed model can provide optimal maintenance plans accordingly.Furthermore,the higher the component’s reliability and maintainability are,the less the times of repair and replacement will be.

Component-based software reliability analysis incorporating imperfect debugging and change-point

Against the deficiencies of component-based software(CBS) reliability modeling and analysis,for instance,importing too many assumptions,paying less attention to debugging process without considering imperfect debugging and change-point(CP) problems adequately,an approach of CBS reliability process analysis is proposed which incorporates the imperfect debugging and CP.First,perfect/imperfect debugging and CP are reviewed.Based on the queuing theory,a multi-queue multichannel and infinite server queuing model(MMISQM) is presented to sketch the integration test process of CBS.Meanwhile,considering the effects of imperfect debugging and CP,expressions for fault detection and correction are derived based on MMISQM.Numerical results demonstrate that the proposed model can sketch the integration test process of CBS with preferable performance which outperforms other models.

Nonlinear Mixed-Effects Models for Repairable Systems Reliability

Mixed-effects models,also called random-effects models,are a regression type of analysis which enables the analyst to not only describe the trend over time within each subject,but also to describe the variation among different subjects.Nonlinear mixed-effects models provide a powerful and flexible tool for handling the unbalanced count data.In this paper,nonlinear mixed-effects models are used to analyze the failure data from a repairable system with multiple copies.By using this type of models,statistical inferences about the population and all copies can be made when accounting for copy-to-copy variance.Results of fitting nonlinear mixed-effects models to nine failure-data sets show that the nonlinear mixed-effects models provide a useful tool for analyzing the failure data from multi-copy repairable systems.

A recognition model of survival situations for survivable systems

Due to the lack of pre-recognition and post- prediction in existing survivable systems, a recognition model of survival situations for survivable systems is proposed. First, the survival situation data is clustered into several survival clusters with different service levels based on the Ward method, and then the survival clusters are classified and recognized by means of the error-eliminating decision-making method, which can realize the pre-recognition of the system＇s survival situation. Secondly, the differentiated survival situation data is used to generate stationary predicting sequences. The autoregressive integrated moving average （ARIMA） model is constructed, and the stability, randomness and reversibility index of the model are verified by the auto- correlation function and partial auto-correlation function. Finally, fuzzy particles and the residual correction for the support vector regression （SVR） model are applied to realize the post-prediction of the survival situation. Compared with traditional decision-making methods, the simulation experiments show that the pre-recognition module can not only cluster the survival situation data and identify the service ranks, but can also recognize the illegal users. According to the prediction of abnormal situations numbers and residual correction, the model can effectively realize the post- prediction of survival situations for survivable systems.

Application of dynamic programming to structural repairing strategies

A model of dynamic programming for repairing strategies of concrete structures during a projected service period is proposed, which takes into account the degradation in strength of components and the probability of accidental load. This model takes the safety grade of a structural system as the state variable of repairing strategies, and incorporates economic factors including expected repair cost, property loss due to structure failure, goods and material loss due to structure failure, loss of production interrupt due to structure failure, and inspection cost in decision making. It is found that the optimal repairing strategies are sensitive to the probability of accidental loads as well as the failure costs. The practicality of the model is demonstrated by an example.

Research on Preventive Maintenance Strategy of Simulator Based on Reliability Theory

Based on the theory of reliability, this paper studies the preventive maintenance strategy of the simulator with incomplete maintenance, and establishes the preventive maintenance model with the aim of simulating the maintenance cost and simulating machine availability. The main contents of this paper are as follows： Firstly, this paper introduces the background and significance of this paper, expatiates the relevant concepts and mathematical foundation of simulator maintenance related theory and reliability maintenance thought, simulator performance degradation law, Weibull parameter estimation method, As the center of the maintenance （RCM） theory of system maintenance decision analysis.

The Linear Stability of a Solution of a Parallel Redundant Repairable System

In this paper,the solution of a parallel redundant repairable system is investigated.by using the method of functional analysis.Especially,the linear semigroups of operator theory on Banach space,we prove the existence of the strictly dominant eigenvalue,and show the linear stability of solution.

WELL-POSEDNESS OF THE MODEL DESCRIBING A REPAIRABLE,STANDBY,HUMAN & MACHINE SYSTEM

By using the strong continuous semigroup theory of linear operators we prove the existence of a unique positive time-dependent solution of the model describing a re-pairable, standby, human & machine system.

FURTHER RESEARCH OF A NEW KIND OF SERIES REPAIRABLE SYSTEM

This paper is devoted to studying the uniqueness and existence of the system dynamic solution by using C0-semigroup theory and discussing its exponential stability by analyzing the spectrul distribution of system operator and its quasi-compactness. Some primary reliability indices are discussed with the eigenfunction of system operator and the optimal vacation time to get the maximum system profit is analyzed at the end of paper.

Various Effective Resist Diffusion Lengths Methodology for OPC Model Calibration

A various effective resist diffusion lengths methodology for OPC model calibration is proposed,which considers the discrepancy of effective resist diffusion lengths between 1D and 2D patterns. An important step of this methodology is to set up a new calibration flow that lets 1D and 2D patterns have the same optical parameters but different effective diffusion lengths. Furthermore, a design for manufacturing （DFM） interaction is suggested in the calibration flow of the pro- posed model. From the CD errors of fitting results and the comparison between simulated contours and SEM images,it is found that the various effective resist diffusion lengths model calibration methodology results in a more accurate and stable model.