几种厚板翻板机的运动仿真与分析

对翻板机进行了描述和分类,并分析和模拟了四杆机构式、液压式翻板机的运动状态和受力情况;利用Inventor软件对翻板机进行了动态演示,最后对机构的荷载进行全面计算,为翻板机设计选型、缩短翻板周期以及电机选型方面提供了参考依据。     

斜面式三通分料器的设计及应用

通过分析翻板式三通分料器的结构及使用中存在的一些缺点 ,介绍了斜面式三通分料器的设计和应用效果。     

计算机辅助曲柄摇杆式翻板机的最优化设计

本文对目前冶金工厂所使用的双臂曲柄摇杆式翻板机进行了机构的最优化设计,编制了完整的软件,这一软件对于此类翻板机及具有类似机构的机器的最优化设计具有一定的参考价值。     

双臂曲柄摇杆式翻板机机构设计及改进

本文利用优化设计的结论，给出了中厚板车间使用的双臂曲柄摇杆式翻板机机构设计的详细方法。这种方法对于此类翻板机的设计及改进具有一定的参考价值。     

双臂曲柄摇杆式翻板机机构设计及改进

双臂曲柄摇杆式翻板机具有独特的优点，因此在国内中厚板生产中得到广泛应用。通过优化设计的结论，给出了这种翻板机机构参数的确定方法，利用这种方法进行翻板机的设计和改进是完全可行的。     

中厚板翻板机的设计与仿真

采用解析法[1]初步确定翻板机机构的参数,然后利用ADAMS软件对其进行运动仿真,再现交接板的全过程.根据仿真结果进一步修改模型参数,再仿真,最后得到一组最佳的机构参数,从而完成翻板机的机构设计.     

翻板机存在问题及解决措施

针对济钢中厚板厂翻板机在使用过程中发现的问题，通过对翻板机结构的力学计算及理论分析，找出存在问题的原因，并提出改进的措施。     

钢带卷打大包装置改进

分析了目前中国热轧立式卷取窄带钢几种常见打大包方式及其缺点,设计了新的钢带卷打大包装置——液压小车偏心翻板式打大包装置,其使用效果良好。     

中板翻板机拉杆和撑杆受力分析及能力验算

随着近两年酒钢中板品种钢和不锈钢轧制比率的提高,对翻板机的使用频率和工作强度也逐步加大,导致翻板机在2017年2月份接连出现了两次连杆断裂设备事故,一次是翻板机短拉杆断裂,另一次是翻板机翻臂撑杆断裂,并间接引发短拉杆再次断裂,为能够准确掌握翻板机拉杆、撑杆的承载能力,同时控制好现场翻板机翻板重量,避免因超载等原因造成拉...     

皮带卸料斗翻板的使用及改进

在炼铁厂原料上料皮带系统中，翻板是改变原料输送方向的一种机械。原使用电液推杆式翻板和机械卷筒式翻板时，常有翻板在关闭或开启时产生顶死现象，致使翻板主轴弯曲变形或扭断事故发生。现改用曲柄钢丝绳式翻板机后，彻底解决了翻板在关闭或开启时的死点问题，保证了设备的正常运行。     

Redundancy of autocrine loops in human osteosarcoma cells

With the aim of identifying innovative therapeutic strategies for osteosarcoma patients who are refractory to conventional chemotherapy, we analyzed the in vitro effects of the blockage of autocrine circuits. Since the insulin-like growth factor-I receptor (IGF-IR)-mediated loop is relevant to the growth of osteosarcoma, we analyzed the activity of the IGF-IR-blocking antibody alphaIR3 in both sensitive and multidrug-resistant osteosarcoma cell lines. Only limited effects, however, were observed, suggesting the simultaneous existence of other autocrine circuits. Indeed, in a representative panel of 12 human osteosarcoma cell lines, in addition to the IGF-IR-mediated circuit, we demonstrated also a loop mediated by epidermal growth factor receptor as well as the presence of nerve growth factor, low-affinity nerve growth factor receptor as well as tyrosine receptor kinase A in the great majority of osteosarcomas. Therapies based on the inhibition of single circuits may have only limited effects in osteosarcoma, whereas the use of suramin, a drug which, besides other activities, non-selectively interferes with the binding of growth factors to their receptors, appears as a promising alternative, in both sensitive and drug-resistant osteosarcoma cells.     

预热烘烤对钢包热行为的影响研究

结合H钢厂的实际情况,采用有限元分析法对新钢包温度场进行研究,进而采用ANSYS数值模拟软件对钢包从烘烤至周转过程进行了数值模拟,重点分析了预热烘烤对新钢包热状态及钢水温度的影响,并进行了试验验证。结果表明:新钢包预热烘烤25 h虽然达到红包状态,且包壁温度趋于热饱和,但是包底仍有蓄热升温空间,周转后钢包造成钢水的最大温降约10℃;预热烘烤55 h后,钢包整体趋于热饱和,周转后钢包造成钢水温降不到1℃,因此可知理想的预热烘烤时间为55 h,为炼钢厂钢包烘烤制度及出钢温度制度的制定提供了参考。     

Level and time effects of recruitment sources on early voluntary turnover.

To better understand the effects of recruitment source on the level and timing of organizational departure, a turnover model incorporating dynamic predictors was examined. A large, longitudinal sample containing both stayers and leavers was analyzed with parametric survival models. Results indicate that the turnover hazard function for individuals recruited through personal recruitment sources was lower early in an employee’s tenure than for individuals recruited through formal sources. Moreover, the peak of the turnover hazard was delayed significantly for such employees. However, the turnover rate differential due to the use of personal recruitment methods clearly diminished as tenure increased. Further, the recruitment source effect on the turnover hazard was partially mediated by job satisfaction. The pattern of results observed expands understanding of the unfolding model of turnover. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Postbuckling of Pressure-Loaded Functionally Graded Cylindrical Panels in Thermal Environments

A postbuckling analysis is presented for a functionally graded cylindrical panel of finite length subjected to lateral pressure in thermal environments. Material properties are assumed to be temperature dependent, and graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The governing equations of a functionally graded cylindrical panel are based on Reddy’s higher-order shear deformation shell theory with von Kármán–Donnell-type of kinematic nonlinearity and include thermal effects. The two straight edges of the panel are assumed to be simply supported and two curved edges are either simply supported or clamped. The nonlinear prebuckling deformations and initial geometric imperfections of the panel are both taken into account. A boundary layer theory of shell buckling, which includes the effects of nonlinear prebuckling deformations, large deflection in the postbuckling range, and initial geometric imperfections of the shell, is extended to the case of functionally graded cylindrical panels. A singular perturbation technique is employed to determine the buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling behavior of simply supported, pressure-loaded, perfect and imperfect, functionally graded cylindrical panels with two constituent materials under different sets of thermal environments. The influences played by temperature rise, volume fraction distributions, transverse shear deformation, panel geometric parameters, as well as initial geometric imperfections, are studied.     

Effects of injurious compression on matrix turnover around individual cells in calf articular cartilage explants

The effects of mechanical injury on the metabolism of cartilage matrix are of interest for understanding the pathogenesis of osteoarthrosis and the development of strategies for cartilage repair. The purpose of the present study was to examine the effects of injury on matrix turnover in a calf articular cartilage explant system for which the effects of mechanical loading on cell activity and the cell-mediated pathways of matrix metabolism are already well characterized. New methods of quantitative autoradiography were used in combination with established biochemical and biomechanical techniques for the analysis of cell and matrix responses to acute mechanical injury, with particular attention to the processes of localized matrix turnover in the cell-associated matrices of individual chondrocytes. Matrix deposition and turnover around cells in control explants was spatially dependent, with the highest rates of proteoglycan deposition and turnover and the lowest rates of collagen deposition (as indicated by [3H]proline autoradiography) occurring in the pericellular matrix. Injurious compression was associated with (a) an abrupt decrease in the tensile load-carrying capacity of the collagen matrix, apparently associated with mechanical failure of the tissue, (b) a considerable but subtotal decrease in cell viability, marked by the emergence of an apparently inactive cell population interspersed within catabolically active but abnormally large cells, and (c) sustained, elevated rates of proteoglycan turnover, particularly in the cell-associated matrices of apparently viable cells, which involved the increased release of aggregating species in addition to a spectrum of degradation fragments that were also in controls. These results may represent an in vitro model for the responses of chondrocytes and the cartilage extracellular matrix to mechanical injury.     

大型高炉转炉铁钢界面铁水温降分析

介绍了鞍钢大型高炉转炉铁钢界面工艺流程,分析了影响铁水温降和铁钢界面系统优化的因素。分析表明,铁水罐运行数量是影响温降的关键因素。通过采取优化鱼雷罐运行的措施,根据炼钢工序的生产节奏综合配备鱼雷罐,并对鱼雷罐的周转节点进行约束,匹配高炉铁水供应节奏,组织铁水调运,使鱼雷罐的平均周转次数提高到3.34次/日,运输过程温降达0.96℃/min。     

Personality, work characteristics and employee well-being: A longitudinal analysis of additive and moderating effects.

This study tested the longitudinal influence of personality (measured by the characteristics growth need strength, negative affectivity [NA], and upward striving) on 3 psychological outcomes (intrinsic work motivation, emotional exhaustion, and turnover intention), using a pattern of specific relationships between work characteristics and these outcomes as a framework. The study hypotheses were tested in a multioccupational sample consisting of bank employees and teachers, using a 2-wave panel design with a 1-year time interval and structural equation modeling. NA had a cross-lagged direct and additive relationship with emotional exhaustion and also moderated the relationship between Time 1 workload and Time 2 emotional exhaustion. The authors concluded that NA may have multiple effects on emotional exhaustion that persist over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of alendronate on bone turnover markers in early postmenopausal women

BACKGROUND: Alendronate sodium (Fosamax, Merck, Sharp & Dohme, Whitehouse Station, NJ, USA) is an aminobisphosphonate that can inhibit osteoclast-mediated bone resorption activity to reduce bone turnover rate and improve progressive gains in bone mass. METHODS: This was a randomized, double-blind, placebo-controlled study comparing the effects on bone turnover markers between daily treatment with alendronate sodium 10 mg and placebo. Forty early postmenopausal women completed three months of treatment. The bone turnover rate was determined by measuring the biochemical markers at baseline, week 6 and at the end of the three-month treatment period. All adverse events were recorded during each follow-up visit. RESULTS: Patients receiving alendronate treatment had a significant decrease in urinary excretion of the bone resorption marker deoxypyridinoline (Dpd) as well as one of the bone formation markers, bone-specific alkaline phosphatase (AlkP-B). Patients receiving placebo tended to have increased urinary excretion of bone resorption and formation markers. At the end of three months, the mean percentage change of Dpd and AlkP-B from baseline in the group receiving 10 mg alendronate was 30.49% and 29.45% reduction, respectively. The placebo group had 2.39% and 1.52% increase, respectively. Overall, three biochemical markers (Dpd, AlkP-B and osteocalcin) differed significantly between the treatment and control groups after three months of treatment. The drug was well tolerated, without a significant increase in incidence of adverse effects such as gastrointestinal discomfort and esophageal irritation. CONCLUSIONS: Bone turnover rate decreased quickly following drug administration. The incidence of adverse effects did not differ significantly between the alendronate and placebo groups. Alendronate is, therefore, recommended as an effective nonhormonal treatment for postmenopausal osteoporosis.     

Postbuckling of Axially Loaded Functionally Graded Cylindrical Panels with Piezoelectric Actuators in Thermal Environments

A compressive postbuckling analysis is presented for a functionally graded cylindrical panel with piezoelectric actuators subjected to the combined action of mechanical, electrical, and thermal loads. The temperature field considered is assumed to be of uniform distribution over the panel surface and through the panel thickness and the electric field considers only the transverse component EZ. The material properties of the presently considered functionally graded materials (FGMs) are assumed to be temperature-dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents, whereas the material properties of the piezoelectric layers are assumed to be independent of the temperature and the electric field. The governing equations are based on a higher-order shear deformation theory with a von Kármán-Donnell-type of kinematic nonlinearity. A boundary layer theory for shell buckling is extended to the case of hybrid FGM cylindrical panels of finite length. The nonlinear prebuckling deformations and initial geometric imperfections of the panel are both taken into account. A singular perturbation technique is employed to determine the buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the compressive postbuckling behavior of perfect and imperfect FGM cylindrical panels with fully covered piezoelectric actuators, under different sets of thermal and electrical loading conditions. The effects due to temperature rise, volume fraction distribution, applied voltages, panel geometric parameters, in-plane boundary conditions, as well as initial geometric imperfections are studied.     

Turnover functionality versus turnover frequency: A note on work attitudes and organizational effectiveness.

Tested whether work attitudes, widely praised as predictors of turnover frequency (i.e., the number of separations), are also useful predictors of turnover functionality (i.e., the nature of separations). Measures on job satisfaction, organizational commitment, job involvement, motivation to turnover, and turnover frequency and functionality were obtained from 112 retail salespersons. Results indicate that (a) the traditional measure of turnover frequency overstates the detrimental effects of turnover on organizational effectiveness, in that 53% of the turnover was functional and (b) turnover functionality, which emphasizes the performance levels of stayers and leavers, is unrelated to work attitudes. Findings suggest that organizations should not devote resources to programs designed to improve employee attitudes, based solely on the expectation that decreasing turnover frequency will result in beneficial consequences. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)