单片机在条形码扫描仪中的应用     

沈群群 《湖州职业技术学院学报》2005,3(2):89-91

利用MCS-51单片机内的一个逻辑器件和单片机的输出巧妙地得到一个外部中断控制信号，该信号的宽度对应扫描到的脉冲宽度。它处上升沿时，启动单片机内的定时器，下降沿时，停止单片机内的定时器，并请求中断。统计出在该信号为高电平期间的计数脉冲的个数，便可算出该信号高电平的持续时间，即脉冲宽度。在中断服务程序中对定时器采集的数据进行提取，这个数据便是扫描到的脉冲宽度。这一扫描方法的电路结构简单，实用价值高。  相似文献   

平利方言的情态语气词     

周政 《安康学院学报》2006,18(1):8-12,16

本文介绍了陕西平利方言的情态语气词,包括:唦、喔、啦、赦、噢、的、得、啵、的了、的耶、的啰、了啰、去了等,并描写它们的语气表达状态.  相似文献   

连铸数学模型研究的新进展     

吴兴宝 《中山大学学报论丛》1996,(5)

指出迄今文献研究连铸（包含铸锭）数学模型基于单元系相变过程；事实上，钢铁生产中熔化与凝固乃是多元系相变过程．由此出发，建立了连铸的新数学模型；并且，构造了相应的算法以进行数字仿真与生产过程自动控制应用  相似文献   

Use of stochastic simulations to investigate the power and design of a whole genome association study using single nucleotide polymorphism arrays in farm animals     

Auvray B  Dodds KG 《Journal of Zhejiang University. Science. B》2007,8(11):802-806

This paper presents a quick, easy to implement and versatile way of using stochastic simulations to investigate the power and design of using single nucleotide polymorphism (SNP) arrays for genome-wide association studies in farm animals. It illustrates the methodology by discussing a small example where 6 experimental designs are considered to analyse the same resource consisting of 6006 animals with pedigree and phenotypic records: (1) genotyping the 30 most widely used sires in the population and all of their progeny (515 animals in total), (2) genotyping the 100 most widely used sires in the population and all of their progeny (1102 animals in total), genotyping respectively (3) 515 and (4) 1102 animals selected randomly or genotyping respectively (5) 515 and (6) 1102 animals from the tails of the phenotypic distribution. Given the resource at hand, designs where the extreme animals are genotyped perform the best, followed by designs selecting animals at random. Designs where sires and their progeny are genotyped perform the worst, as even genotyping the 100 most widely used sires and their progeny is not as powerful of genotyping 515 extreme animals.  相似文献   

Mixed schools versus single-sex schools: are there differences in the academic results for boys and girls in Catalonia?     

Maribel Garcia-Gracia  Trinidad Donoso Vázquez 《International Journal of Inclusive Education》2016,20(2):149-167

This study carries out a comparative analysis of achievement according to gender between mixed and single-sex schools in the region of Catalonia, Spain, for the subjects of Spanish, Catalan, English and Mathematics. After a brief contextualisation, a review of the main findings from international studies on differences in results for mixed schools and single-sex schools is then presented. We then outline our methodology and research-analysis plan. The study has been developed around a specific use of results obtained by students over the last year of primary school (12 years old) and over the last year of obligatory secondary education (16 years). For this comparison, the statistical technique of Propensity Score Matching was used. All segregated schools in Catalonia were chosen, representing a total of 15, of which 9 are girls-only and 6 are boys-only (with a total of 1503 students); additionally, a sample was used of 10 mixed schools, similar in terms of social make-up, that is, middle- and upper-class students (with a total of 1217 students). In general, the results corroborate international research. Results indicate that differences in achievement depending on gender in segregated or mixed schools are not related to factors of school organisation. We also come to conclusions with respect to the limitations arising from circumscribing school performance in curricular subjects, and to the need to consider further indicators within the teaching-and-learning process in terms of gender and emotional development; student attitudes and behaviour; self-concept and – most especially – teacher expectations, their teaching practices and the effects of these on self-concept and single-sex school performance.  相似文献   

Promoting teachers’ implementation of culturally and contextually relevant class‐wide behavior plans          下载免费PDF全文

Lindsay M. Fallon  Sadie C. Cathcart  Emily R. DeFouw  Breda V. O'Keeffe  George Sugai 《Psychology in the schools》2018,55(3):278-294

Disproportionality in disciplinary actions for certain racial groups has been well documented for several decades. In an effort to support all students, specifically those who are culturally and linguistically diverse, many have called for adopting a multitiered system of support framework that is considerate of student culture and school context. This framework applies to supporting students’ learning and behavior across settings, particularly in the classroom. To bridge existing gaps between theory and practice, this empirical study sought to evaluate whether teachers who self‐assessed their own use of culturally and contextually relevant practices would implement a class‐wide behavior plan with high levels of implementation fidelity. Results indicated that teachers who engaged in self‐assessment and training did implement the plan with high levels of implementation fidelity, particularly when given performance feedback. Additionally, students tended to display slightly higher rates of academic engagement upon consistent implementation of the plan.  相似文献   

福建东游人名的重名问题——中国农村语言生活的一项田野调查     

于芳 《南平师专学报》2007,26(1):63-66

重名是人名命名中一个尽量避免而又无法消除的问题。本文以福建省建瓯市东游镇的将近4万镇民的人名为样本,对其重名问题作了穷尽性的田野调查,并探讨了造成重名的本质性因素和尽量避免重名的有效策略。  相似文献   

Average modeling of Single Stage Flyback PFC+Flyback DC/DC converter     

沈淼森  康婉莹  钱照明 《Journal of Zhejiang University. Science. B》2002,(1)

ＩＮＴＲＯＤＵＣＴＩＯＮＰＦＣｃｉｒｃｕｉｔｒｙｓｉｍｕｌａｔｉｏｎｈａｓｓｏｍｅｉｎｈｅｒｅｎｔｄｉｆｆｉｃｕｌｔｉｅｓ,ａｓｔｗｏｆｒｅｑｕｅｎｃｉｅｓｈａｖｅｔｏｂｅｃｏｎ ｓｉｄｅｒｅｄｄｕｒｉｎｇｓｉｍｕｌａｔｉｏｎ :ｏｎｅｉｓｔｈｅｓｗｉｔｃｈｉｎｇｆｒｅｑｕｅｎｃｙｏｆａｂｏｕｔ 50ｋＨｚ,ａｎｏｔｈｅｒｉｓｔｈｅｍａｉｎｓｆｒｅｑｕｅｎｃｙｏｆ50ｔｏ 60Ｈｚ.Ｉｔｃａｕｓｅｓａｎｅｘｔｒｅｍｅｌｙｌａｒｇｅｄｙｎａｍｉｃｏｐｅｒａｔｉｏｎｒａｎｇｅ .Ｔｏｓｕｒｍｏｕｎｔｔｈｅｓｅｄｉｆ…  相似文献   

应用AT89C51单片机监测火车上衡计量     

李玲  马志才 《辽宁科技学院学报》2001,3(4):20-21

大中型冶金企业进出厂物资计量是生产经营活动的一个重要环节，多采用静态或动态轨道衡为主的计量手段，由于动态轨道衡误差较大，一般物资出厂大多采用静态轨道衡，本文主要介绍应用AT89C51单片机监测火车上衡计量的检测方法及硬件，软件设计，具有较好的实用性。  相似文献   

对股四头肌肌电图单谱指标与功率输出的研究   总被引：2，自引：0，他引：2  

徐文静  彭如心  郭静璐 《大连大学学报》2005,26(2):72-74,77

[目的]探讨30s内全力蹬踏自行车运动过程中,股四头肌SEMG指标与输出功率的变化特征.[方法]测试30s全力蹬踏加有7.5%自身体重负荷的功率自行车过程中的功率输出和MegaWin肌电测试系统记录股四头肌外侧肌在整个过程中的肌电变化,进行运动中的开始5s和最后5s的肌电参数MF(Median Frequency中值频率)、MPF(MeanPowerFrequency平均功率频率)、ZCR(ZeroCrossingRate零点通过率)、AE MG(AveragedEMG平均肌电图)和SPA(SpectrumArea频谱区)分析比较.[结果]①除相对峰值,实验组学生的峰值、最小功率、相对最小功率、平均功率、相对平均功率都极显著大于对照组(P<0.01);②对照组后5s疲劳时MF和MPF极显著增加,ZCR显著增加,AEMG和SPA则极显著下降(P<0.01);实验组则只有AEMG和SPA极显著下降(P<0.01).③实验组与对照组比,前5s肌电图参数MF、MPF和ZCR显著增加(P<0.05),而AEMG和SPA有所下降,但未达显著水平,后5sMF、MPF、AEMG和SPA与对照组无显著差异,仅有ZCR显著增加.[结论]训练和疲劳都使单谱肌电图指标MF、MPF、ZCR增加,使AEMG、SPA下降.提示前5s的单谱肌电图指标MF、MPF、ZCR、AEMG、SPA可反映训练水平,后5s可反映疲劳程度.  相似文献