基于C8051F120的红外双视场调焦控制系统

文章介绍了基于高速单片机C8051F120的红外双视场调焦控制系统，简述了该控制系统的硬件设计和软件流程，采用磁旋转编码器产生脉冲，利用PWM调节直流微电机带动滑块上的移动镜组移动，寄存器中预存储大小视场对焦正确时移动镜组所在位置，设置了微调按钮。在电机运动结束，大小视场调焦基本完成后，使用微调按钮进行微调，直至获得满意的成像质量。扩展了串口通信模块，以方便同上位机进行通信。     

家用摄像机的使用与保养

1 正确使用调焦功能 与照相机一样,要保证拍摄物体的清晰度就必须有调焦机构,摄像机上调焦机构有自动和手动两种。将自动/手动调焦钮置于自动(Auto)位置时,摄像机上寻像器中心位置的物体总是自动达到最佳拍摄距离。有时为了对寻像器中心位置以外物体进行调焦,就应将自动/手动调焦钮置于手动(Manual)位置,否则就不能达到拍摄要求。在摄像时,应随时根据摄像需要来掌握和使用调焦功能,如拍摄的对象移动性大,就应运用手动调焦,或有时所摄录的物体反光太强烈,自动对焦功能可能全失常,也应使用手动调焦功能。     

DS3型水准仪望远镜系统故障判断与排除

水准仪是借助仪器的水平视准线作为基准,进行高差测量的光学仪器,它广泛地用于大地水准测量,地震形变测量,各种工程水准测量与大型精密机械安装等。仪器在使用过程中受到意外的震动或者在经过拆卸而重新安装之后,往往由于各光学零件和金属部件未安装到原来正确位置,造成各种部件相对位置的改变等,因此,必须进行调整维修。现以常见的DS3型水准仪为例,将望远镜系统故障判断与排除做一介绍。一、目镜部分目镜调焦时,转动困难和有沙沙声。原因是目镜筒的调焦螺纹与目镜座螺纹之间润滑油干涸和灰砂的侵入造成的。需用汽油彻底清洗其中干涸的油泥…     

QX-4隧道清洗车水罐等效力学模型分析

文章通过理论计算分析,可得出隧道清洗车水罐内部液态水晃动的固有频率及振型;通过ANSYS分析软件对水罐及内部液态水进行有限元仿真分析,得到水罐内部液态水晃动的固有频率及振型;对比两者结果,误差在有效范围内,理论计算结果正确;结合理论计算与有限元仿真分析结果建立水罐的等效力学模型,用于隧道清洗车的动力学仿真分析。     

海浪干扰条件下的AUV惯性导航初始对准方法研究

分析了系泊在母船上的AUV捷联惯导(SINS)初始对准算法,建立了海浪干扰条件下AUV的姿态摇摆运动方程,对母船静止和母船晃动情况下AUV的SINS初始对准过程进行了仿真实验。仿真结果表明,在母船静止情况下失准角能很快收敛;在海浪干扰条件下失准角误差出现了周期性晃动,但晃动幅度较小,达到了AUV的SINS初始对准精度要求。     

浅析定位误差及其计算

机械加工过程中,工件在夹具中定位时,定位误差是影响加工精度的重要因素之一,因此,必须熟练掌握定位误差的分析与计算,以保证零件加工精度的要求。文章通过分析定位误差产生的原因,举例说明了定位误差的计算方法。     

设计机床夹具时计算定位误差容易出错的几个问题

本文分析了计算定位误差△dw过程中,容易出现错误的几个问题,并提出其解决的计算方法.通过分析机床夹具定位基准的移动方向与工序基准同定位基准间的距离尺寸无关或有关两种情况,探讨确定机床夹具中的定位误差计算式中加、减符号的方法,得出简化工件在机床夹具中的定位误差的计算方法.     

材料试验机误差来源与常见故障及解决方法

材料试验机是测量精度较为准确的计量仪器,但是试验机在移动、 安装、 调试和使用过程中会出现多种故障,也会产生示值误差.为此,需基于试验机原理和结构对故障、 误差产生的原因进行分析,对其进行修正,为材料质量控制提供准确依据.本文首先对材料试验机进行简要分析,其次对误差产生的原因和解决办法进行论述,然后总结了常见故障产生的原因及解决办法.     

设计机床夹具时计算定位误差容易出错的几个问题

本文分析了计算定位误差△dw过程中，容易出现错误的几个问题，并提出其解决的计算方法。通过分析机床夹具定位基准的移动方向与工序基准同定位基准间的距离尺寸无关或有关两种情况，探讨确定机床夹具中的定位误差计算式中加、减符号的方法，得出简化工件在机床夹具中的定位误差的计算方法。     

电能传输过程中互感器的误差分析

互感器的额定变比(标称变化)是一个确定的量用于计算,而实际变比是一个变量,随互感器的运行工况(原边输入量与副边负载阻抗)的变化而变化。互感器的额定变比可以认为是指定的标准工况(一定的原边输入量及副边负载)下的实际变比。因此,离开标准工况运行即出现误差-计算值与实际运行量的差别。结合实际,针对电能传输过程中互感器的误差进行了分析。     

企业评价创新——从绩效评估到基于战略聚焦的价值管理

新经济时代的企业环境促使企业管理战略发生了巨大变化,同时又为企业组织与运营模式的创新提供了先进手段。在这种环境下,传统绩效评价模式呈现出诸多方面的缺陷和不适,因此必然要求相应的改变。本文分析了企业绩效评价的研究现状,探讨绩效管理的发展趋势,最后就两种面向战略聚焦的价值管理模式进行评述。     

On the Comparison of Run Orders of Unreplicated 2<Superscript><Emphasis Type="Italic">k</Emphasis>–<Emphasis Type="Italic">p</Emphasis></Superscript> Designs in the Presence of a Time Trend

The response from a factorial experiment carried out in a time sequence may be affected by uncontrollable variables that are highly correlated with the time in which they occur. In such a situation, one possibility is to randomize the run order of the experiment. Another possibility is to use a systematic run order that is robust against time trends. Since randomized run orders make the time trend part of the error, it can be hoped that systematic run orders will be more effective to identify truly active factors. In this paper, a simulation study is used to compare the performances of the randomized and the systematic run orders. The response from an experiment where we have observed a strong time trend is used to demonstrate the influence of a realistic time trend on the run orders under consideration. The performance of the run orders is then measured by taking the probabilities of false rejection and the probabilities of detection of active contrasts. Our results show that the randomized run order managed to keep the nominal level, while the systematic did not. Additionally, when there were active factors, then the systematic run orders did not achieve more power than did the randomized run order.     

Structural FECM: Cointegration in large‐scale structural FAVAR models

Starting from the dynamic factor model for nonstationary data we derive the factor‐augmented error correction model (FECM) and its moving‐average representation. The latter is used for the identification of structural shocks and their propagation mechanisms. We show how to implement classical identification schemes based on long‐run restrictions in the case of large panels. The importance of the error correction mechanism for impulse response analysis is analyzed by means of both empirical examples and simulation experiments. Our results show that the bias in estimated impulse responses in a factor‐augmented vector autoregressive (FAVAR) model is positively related to the strength of the error correction mechanism and the cross‐section dimension of the panel. We observe empirically in a large panel of US data that these features have a substantial effect on the responses of several variables to the identified permanent real (productivity) and monetary policy shocks.     

客户采购关注点对再制造产品购买意愿的影响研究——基于政府促进政策的调节效应研究

近年来,国家出台各种政策措施促进再制造产业发展,但是由于多方面原因,客户在产品选择上往往将再制造产品列为下策。本研究采用扎根理论分析客户采购关注点对再制造产品购买意愿的影响,并检验了政府促进政策的调节效应。研究发现,客户对品牌的信任、质量感知、成本控制意识对再制造产品购买意愿有正向影响,而客户的社会责任观对再制造产品购买意愿影响不显著。此外,政府的促进政策对客户的品牌信任、质量感知、社会责任观和再制造产品购买意愿之间的关系有正向调节效应,但是在政府的促进政策中,直接补贴对成本控制意识和再制造产品购买意愿之间的关系没有调节效应,而“以旧换再”对这两者有正向调节效应。该研究结论的理论意义在于从再制造这一特殊工业品角度研究了购买意愿的影响因素及其调节机制,有助于完善组织市场购买行为理论;实践意义为有助于再制造企业更好地吸引客户购买,有助于提高政府促进政策的有效性提供指导建议。     

Determination of Long‐run and Short‐run Dynamics in EC‐VARMA Models via Canonical Correlations

This article studies a simple, coherent approach for identifying and estimating error‐correcting vector autoregressive moving average (EC‐VARMA) models. Canonical correlation analysis is implemented for both determining the cointegrating rank, using a strongly consistent method, and identifying the short‐run VARMA dynamics, using the scalar component methodology. Finite‐sample performance is evaluated via Monte Carlo simulations and the approach is applied to modelling and forecasting US interest rates. The results reveal that EC‐VARMA models generate significantly more accurate out‐of‐sample forecasts than vector error correction models (VECMs), especially for short horizons. Copyright © 2015 John Wiley & Sons, Ltd.     

The significance of sustained entrepreneurial orientation on performance of firms – A longitudinal analysis

This study focuses on the importance of changes in entrepreneurial orientation (EO) over time for subsequent firm performance, and the significance which inimitable resources (networks, governance system and unique competence) might have in this connection. Hypotheses are developed to test the effects that changes in EO level over a time period and resources have on subsequent firm performance. The study is based on data from 168 Norwegian SMEs, interviewed both in 2000 and 2003. The primary contribution of this study is that a change in EO over time (increased or decreased), may be of importance for a firm's performance represented by performance compared to competitors, and employment growth. A focus on entrepreneurial activities seems to be beneficial in the long run (increasing EO), while the opposite is the case if the EO level decreases. It is especially encouraging to see that firms focusing on EO (increased or the same) are positively associated with employment growth, one of the primary policy goals world-wide. Another contribution from this study is that resources that may be inimitable for firms have some influence on performance compared to competitors. Implications for policy-makers, practitioners and further research are discussed.     

Relationships and resources: the isomorphism of nonprofit organizations’ (NPO) self-regulation

Self-regulation emerges as an option in response to government control of the institutional environment of nonprofit organizations (NPOs). While most research focuses on conceptualizing and arguing for self-regulation, this study examines self-regulation through the lens of the institutional perspective by focusing on a specific institutional domain of NPOs in Lebanon. Results indicate that a certain degree of normative isomorphism, through professionalization, has a positive impact on NPOs’ participation in self-regulation while mimetic practices do not yield the same results; coercive isomorphism is not a significant predictor. The results allude to certain implications both for management practices and for scholarly research.     

Variables control chart limits and tests for special causes

Control charts are used to detect problems in control such as outliers, shifts in levels or excess variability in subgroup means that may have a special cause. This paper addresses itself to deriving control chart limits based on past data and based on initial samples in a current control situation. We present a general setting for control charts. Furthermore, an overview is given of tests for special causes. The tests are standardized so that the asymptotic type I error does not exceed a fixed level. The distributions of the run lengths of the tests and combinations of tests are also evaluated. We propose to use a low percen-tile of the run length distribution, instead of the average run length, to study the performance of the tests. These indicate that, in particular when tests are combined, the run length percentiles may be too small for practical purposes. It is shown that (nearly) exact control chart limits for observations from a normal distribution exist. The traditional limits differ considerably from the proposed ones and correspond to even smaller run length percentiles.     

卓越视域下的“探究式”教学案例构建刍议——以新疆工程学院“采掘机械”课程教学为例

针对新疆地区工科高校多民族学生混合编班、数理基础差异较大的现实情况,结合新疆工程学院区域应用型本科基础定位,在采掘机械课程教学中采用探究式工程教育理念,构造以问题为驱动核心的教学——实践互动案例。通过围绕模拟矿井平台设备展开的液压支架实践教学过程,说明如何设计无标准答案的发散型主题,激励学生主动参与教学活动并激发学习兴趣,有效诱导学生在实践环境中自主发现和解决问题。     

The Effect of Urbanization and Industrialization on Energy Use in Emerging Economies: Implications for Sustainable Development

This article investigates the impact of two important socio‐economic variables—urbanization and industrialization—on energy consumption in a panel of emerging economies. The results indicate that income increases energy consumption in both the long run and the short run. In the long run, urbanization decreases energy consumption, while industrialization increases it. Long‐run dynamics are important as evidenced by the estimated coefficient on the error correction term. These results have implications for sustainable development. Economic growth policies designed to increase income and industrialization will increase energy consumption. Since most energy needs in emerging economies are currently met by the burning of fossil fuels, economic growth and industrialization policies will be at odds with sustainable development.