计算机硬盘的保养方法

要想保养好我们计算机中的硬盘，首先我们得对计算机硬盘的工作原理有一个简单的了解。硬盘读写信息和录音机录放磁带有点相似，录音机磁带在磁头表面经过就可以完成磁信息和电信号的转换；硬盘存储的信息也是以磁信息的方式，存放在一个或几个金属盘片表面的磁道上；磁道是带有磁介质的金属盘片格式化而来的一圈圈的同心圆；磁头读写信息时，是靠盘片高速旋转时，带动盘片表面的空气运动的气垫原理，悬浮在盘片的上方来完成读写工作的；由此可见，磁头和盘片的距离是很近的。因此，在使用和维护计算机时，要从以下几点来保养计算机的硬盘：     

录像机简单故障的排除

随着人民生活水平的提高,购买录像机的家庭日渐增多。但使用录像机又常为录像机不能正常工作而担忧。这里介绍十几种录橡机故障的排除方法: ①放像时,只有伴音而无图像。这是录像机的视频磁头脏了所致。这时,只要小心清洗(其方法已多有介绍)一下视频磁头,故障即可排除。 ②放像时,图像不稳定或翻滚,有时还伴有干扰条带。首先应仔细调节磁路跟踪钮,如不行,再检查电视机的水平钮,若图像依旧,这时可判断录像机的控制磁头脏了,清洗即可排除(控制磁头常与伴音磁头为一体,设在录像带走带的出口处)。但如果录像控制磁迹录制得不好,也会出现图像翻滚现象,应注意加以识别。     

改单声道录音机为简易卡拉OK机

按照本文所述的改制方法,只需增加一只双声道磁头,一个转换开关,一只电位器,即可使单声道录音机既保持原有功能,又增加卡拉OK伴唱功能和跟磁带学唱的功能。 具体改制方法可分为两个部分: 1 将单声道磁头换成双声道磁头并加装转换开关 (1)拆下原机的单声道磁头,换上阻抗相近的双声道磁头。 (2)将L、R声道的磁头线圈按图1所示,连接在新加的转换开关上。     

生产物流平衡的持续优化在硬盘磁头制造业的应用

以广东某硬盘磁头代工企业生产线为研究对象，运用装配线平整技术，以生产物流平衡为目标分析了设备能力、任务分配、工装改善以及生产计划排配等方面存在的问题：提出并实施了改善方棠。保证了生产线的物流负荷平衡。优化方案的实施使企业生产能力提高并有效地降低了生产线在制堆积的问题，在制品周转从3．2天缩短到2．5天，生产现场的环境也得到了改善。     

巨磁阻抗效应在传感器领域的应用

目前,全球的军事、民用和安全、信息产业、通讯、航空、航海、航天和车辆、工业测量以及自动化等行业,都需要不同类型的传感器,如位置传感器、位移传感器、电流传感器、数字磁罗盘和三维磁强计等。使用巨磁阻抗元件与现有的半导体磁敏元件(霍尔元件等)、磁阻元件、磁通门传感器以及巨磁-电阻元件相比,可以集微     

磁致位移传感器在自行火炮性能测试中的应用

介绍磁致伸缩位移传感器的工作原理和小位移参数的测量方法。该传感器有精度高、寿命长、安装简便的特点。对各种位移量变化的测量是自行火炮性能检测的重要内容,针对现有测试方法存在的不足,提出了基于磁致位移传感器的位移量测试系统并应用于自行火炮性能测试中,通过实验得出:该方法使用操作方便、测量准确、自动化程度高,应用范围广。     

基于Ansoft/Rxmprt和Matlab/Simulink的开关磁阻电机模糊PI控制研究

开关磁阻电机(SRM)以其结构简单,控制方式灵活等优点逐渐得到学术界和工业界的重视。由于SRM的磁链高度非线性,要获得精确的模型较困难。依据实体电机的材料和尺寸参数,利用Ansoft/Rxmprt软件获得了SRM的非线性磁链模型,并将此磁链数据导入到Matlab/Simulink的SRM模型,建立了与实体电机相吻合的模型。最后,基于此模型设计了模糊PI控制算法,通过仿真计算,验证了该控制算法可显著提高SRM调速系统的稳态和动态性能,为设计电机硬件驱动系统提供了理论依据。     

应用高精度磁测方法直接寻找磁铁矿体

通过1/1万的高精度磁法测量,在哈西亚图地区圈出了C1、C2、C3三个异常,从目前成果看,矿致异常的异常特征很明显:异常为南正北负,正磁异常大于负磁异常,峰值较高,当△T在3000 nT-8000nT区间时,梯度陡的磁异常区域,磁铁矿体埋藏深度较浅,一般小于20m,当△T大于8000 nT时,地表可揭露出磁铁矿(化)体。此次普查工作大致查明C2-1、C3磁异常为矿致异常,含矿岩性为矽卡岩,矿床属似层状矽卡岩型铁多金属矿床[4]。     

浅析汽车车身焊接参数调整

在汽车工业中,汽车车身是一个复杂的结构体。由于车身冲压件的材料大都是具有良好焊接性能的低碳钢,所以焊接是现代车身制造中广泛应用的制造方式。焊接是车身制造过程中的一个关键环节,起着承上启下的特殊作用。在目前汽车白车身的制造中主要的焊接方式有电阻焊、CO2气体保护焊和激光焊接。电阻焊运用广泛,电阻焊接的关键在于焊接电流、焊接压力、焊接时间的控制,这三个要素为电阻焊接过程中主要控制的焊接参数,也是焊接过程中比较好监控的焊接参数,所以焊接参数的调整显得至关重要。     

浅析汽车车身焊接参数调整

在汽车工业中,汽车车身是一个复杂的结构体。由于车身冲压件的材料大都是具有良好焊接性能的低碳钢,所以焊接是现代车身制造中广泛应用的制造方式。焊接是车身制造过程中的一个关键环节,起着承上启下的特殊作用。在目前汽车白车身的制造中主要的焊接方式有电阻焊、CO2气体保护焊和激光焊接。电阻焊运用广泛,电阻焊接的关键在于焊接电流、焊接压力、焊接时间的控制,这三个要素为电阻焊接过程中主要控制的焊接参数,也是焊接过程中比较好监控的焊接参数,所以焊接参数的调整显得至关重要。     

Job location and the journey-to-work: An empirical analysis

In this paper we present and estimate a single equation model designed to explain the job-location behaviour of individuals living in a multi-centered metropolitan area. We test the model separately for heads of households and non-heads of households, as well as for the total working population, in order to isolate differences in commuting behaviour between primary and secondary wage earners. The relationships are estimated from 1971 Census, cross-section data using least squares multiple regression.The results of the location equation indicate that wage gradient variables are important determinants of job location for heads of households. On the other hand, non-heads are rather insensitive to the wage gradient. Rather, contrary to the decisions of heads, the job-location choices of non-heads are strongly influenced by socio-economic attributes, notably occupation, family size and age. Clearly, job-location decisions of primary wage earners (usually the household heads) are influenced by earnings-maximizing considerations while secondary earners (non-heads in general) put more weight on other socio-economic factors. The results also suggest that there is a hidden cost associated with uneven directional growth in the Toronto CMA. It is suggestive that urban planning strategies should reflect consideration of the greater desire or need for accessibility on the part of secondary wage earners (non-heads) and the need to balance residential and job opportunities at the extending margin of the urban area.     

Evaluation of critical constructs for measurement of sustainable supply chain practices in lean‐agile firms of Indian origin: A hybrid ISM‐ANP approach

The purpose of this paper is to evaluate the critical criteria that are influencing the successful implementation of sustainable supply chain practices (SSCP) in the lean‐agile manufacturing firm. From the systematic literature review and field professionals' opinion, various criteria that are influencing sustainable supply chain were identified. Data were collected from 16 experts and analysed by an integrated approach of “interpretive structural modeling (ISM) and analytic network process (ANP).” ISM methodology was utilized to get a hierarchical relationship between all criteria. Further, the input to the ANP matrices was taken from the output of ISM, and three organizations that differ in their principle of operation were ranked to find out the extent of implementation of SSCP in the Indian context. The obtained results indicate that “Information technology‐enabled system support (ITS), SC member's awareness and literacy (SAL), Societal issues (SIS), and Scarcity of natural resources (SNR)” were most significant constructs for successful implementation of SSCP for the case organizations.     

Perceptions of instructors and administrators of English language on their professional development needs

The present study aims at investigating the professional development needs of instructors and administrators of English language in public universities in North Iraq. The study also attempts to evaluate the professional development of universities’ instructors in improving their personal and professional career while teaching English as a foreign language. Professional development provides teachers with more knowledge, skills, and experiences either personally or professionally throughout the process of teaching. In this study, qualitative research methods were used. There were forty participants involved in this study including English language and literature instructors, heads of departments, assistant heads of departments, and coordinators employed in the 9 public universities of North Iraq. The results showed that there are still no actual tendencies of professional development as a program to be implemented as a continual process of teaching and learning, and there is a lack of professional development opportunities in public universities in North Iraq. The participants also provided significant suggestions on their professional development needs.

     

WHO WILL RETURN AND WHEN? AN ANALYSIS OF RURAL-TO-URBAN MIGRANTS IN INDIA*

An analysis of temporary migration in India is presented. In particular, the author examines, within a multivariate context, the importance of various socioeconomic factors that influence the future plans of rural-urban migrants and their intended timing of return to the rural area. The data are from a 1975-1976 survey of 1,615 migrant heads of households in Delhi.     

Quality of life and its predictors among Pakistani head of household in district Abbottabad,Pakistan

Quality & Quantity - This study aimed to measure the quality of life (QOL) and its predictors among male and female heads of household in Pakistan. A population-based cross-sectional study in...     

新形势下加强对国有企业“一把手”监督的思考

文章阐述了当前对国有企业“一把手”监督不力的表现，具体分析了监督不力的原因，并提出了加强对国有企业“一把手”监督的对策。     

公路工程中桥头跳车的成因及其防治措施探析

文章分析了公路工程质量的通病之一桥头跳车的危害、成因,并对其防治措施进行了一番探讨。     

青海湖沙漠地区节水器设计

负水头毛细渗灌非常适合青海湖周边沙漠地区的固沙植生,根据毛细渗灌原理对节水器进行设计,考虑植物的需水量,棉线毛细输水量,沙子的输水特性可确定节水器的输水量及入渗点。     

Housing equity,residential mobility and commuting

Highly productive economies require a flexible labor force with workers that move in accordance with the changing demand for goods and services. In times with falling housing prices, the mobility of home owning workers may be hampered by a lock-in effect of low or even negative housing equity. This paper explores the effect of housing equity on both the residential mobility and the commuting pattern of homeowners. We merge administrative registers for the Danish population and properties and get highly reliable micro data for our analysis. We find that low and negative housing equity substantially reduces residential mobility among homeowners. The negative effect of locked-in low equity families on labor market mobility may be mitigated by commuting. However, our results show that family heads in low or negative equity homes are not found to commute more than households with higher housing equity, but also that a considerable fraction of home owning family heads commute. The analysis of the joint decision of homeowners to commute or move shows that the option of moving, as an alternative to not moving and not commuting, is chosen by five to six percent of homeowners with low housing equity, while the option of not moving but commuting is chosen by 60%.     

Differences in Opportunities? Wage,Employment and House‐Price Effects on Migration*

Most empirical studies of individual migration choice analyse factors associated with out‐migration from an origin location. In contrast, we model the migration decision within the context of potential destinations, combining British panel data over the period 1992–2008 with other data sources. Contrary to earlier micro studies, we show that differences in house prices levels (but not growth) are important determinants of household migration for homeowners. Unemployed individuals respond to regional differences in expected individual wages, whereas the employed are more sensitive to employment opportunities. Our evidence is consistent with partners of heads of households being tied migrants.