一种特殊系统误差的探讨

灵敏电流计特性实验中，相对误差达30％左右，经反复实验发现，误差原因出在接线柱外，经过改进，相对误差减小到5％之内，但在不加外电源时，电路中仍存在微小电流，其中的原因，仍需探讨。     

一种特殊系统误差的探讨

灵敏电流计特性实验中，相对误差达30％左右，经反复实验发现，误差原因出在接线柱外，经过改进，相对误差减小到5％之内，但在不加外电源时，电路中仍存在微小电流，其中的原因，仍需探讨。     

电容液位计测量液氮气瓶液位的实验研究

为了探究电容式液位计在液氮绝热气瓶液位测量中的精度及相对误差变化规律,利用单电容和三电容液位计进行液位测量实验,并与称重实验进行对比验证。结果显示:单电容和三电容液位计的相对误差分别为4.9%和1.9%,单电容液位计相比目前应用的圆筒电容液位计平均测量精度已提升了5%左右,三电容液位计测量精度较单电容提高3%。从信号变送器的设计方面分析精度提高的原因为三电容液位计对液氮介电常数进行了精确修正,探究得到电容液位计相对误差的变化规律及原因。实验中使用的电容液位计还可用于液氢、液氧以及液化天然气等低温容器的液位测量中,能够促进低温液体在各领域中的应用推广。     

燃烧热测定实验的改进措施

针对燃烧热测定实验中存在的实验成功率低、实验时间长和数据误差大,进行了实验技术改进。采用温度温差仪测定外桶的温度,以外桶温度0℃为基准,标准物质和待测物质用水量相同的实验措施,运用Excel软件对数据进行处理,对萘的燃烧热进行测定并计算相对误差。结果表明,萘的燃烧热测定的相对误差为0.7%,并缩短了实验时间和简化了实验数据处理,提高了实验的成功率。以外桶温度为0℃记录数据,方便数据处理;标准物质和待测物质用水量相同,简化实验操作和数据处理,节约了时间,提高了效率;用Excel软件绘制雷诺温度校正图,极大地提高准确度,减小了误差。     

透镜成像中球面像差和色像差的分析与校正

薄透镜成像中球差和色差对成像效果有严重的影响,学生在测量透镜过程中很难确定焦点的正确位置,使得测量误差很大 . 通过分析薄透镜成像过程中球差和色差产生的原因,采用在实验中加入光阑和滤光片.通过实验对比发现,加入光阑和滤光片可有效地减小像差和色差对实验结果的影响,从而达到减小实验相对误差的目的.     

助燃法在燃烧热测定实验中的实践与应用

用计算机自动控制或手控操作测定燃烧热实验时,在点火丝和药片之间滴一滴非挥发性机油予以助燃,确保了实验点火的100%成功,实验时间由4.0~5.0 h减少至2.0~2.5 h,充氧压力由20 atm可降至10 atm,实验相对误差在2%以下,远远小于5%的实验要求,且完美解决了该实验因点火失败而带来的费时费力操作烦恼.通过在实验教学中反复应用,效果很好,值得同行借鉴和推广.     

对“测定空气中氧气的含量”实验的再改进——以“铜粉氧化法”为例

2012年鲁教版初中化学教材加热铜粉测定空气中氧气含量实验存在实验条件较难控制、实验相对误差平均值较大、成功率低等问题。为此,在查阅有关文献并结合实践经验的基础上,主要从保证装置气密性角度对利用“铜粉氧化法”测定空气中氧气含量实验继续加以改进,对有关实验用品的选择和实验步骤进行了优化,达到了减少实验相对误差、提高实验成功率的目的。     

利用神经网络算法推算超额吉布斯自由能

利用神经网络算法推算了超额吉布斯自由能GEm,并将推算结果与实验结果进行了比较,推算的平均相对误差均在1.42%以内。     

偏最小二乘分光光度法同时测定混合稀土氧化物中的Eu、Sm、Pr、Ho、Tm和Nd

本文研究了EGTA和DTPA对稀土元素可见光区的吸收光谱的增敏作用.采用偏最小二乘(PLS)分光光度法拟定在DTPA—六次甲基四胺体系中测定Eu、Sm和Pr、Ho;在EGTA—六次甲基四胺体系中测定Tm.Nd.实验结果表明对合成样品的测定相对误差均小于6%,回收率为94～105%,混合稀土样品测定结果与x—荧光配分值相比较相对误差小于10%,本方法适合于一般的工业分析,用于测定指定的六个稀土元素,设备简单,操作方便.     

平行四边形法则实验中误差的定性半定量分析

通过不确定度传递公式和相对误差理论,可对中学平行四边形法则实验中几处误差的产生进行定性半定量分析。在计算合力理论值时不确定度的传递、两分力夹角的选取和作图过程中相对不确定度及相对误差等几个方面,将对实验结果造成影响。避免这些因素,学生在实验操作中能够减小误差的产生。     

The Sources of Error in Spanish Writing (Research Note)

The main aim of this study was to determine the pattern of errors in Spanish spelling. Specifically, we were interested in discovering if all Spanish words have similar levels of spelling difficulty or whether there are types of words that cause a high percentage of spelling errors. 972 children aged between 8 to 10 years were requested to write a short spontaneous story. Our objective was to analyse and to propose a classification system for the errors made by children in the initial stages of the acquisition of spelling skills. The results indicate (a) that the diverse forms of only 20 Spanish words produce 36 per cent of the spelling errors in Spanish, and (b) that substitution is the most frequent type of error (68 per cent of total errors), which occurs as a consequence of an inadequate knowledge of the rules of phoneme-grapheme correspondence. These findings have relevance for the teaching of writing in Spanish.     

Is job sharing worthwhile? A cost-benefit analysis in UK universities

Around 60 per cent of UK universities practice job sharing. This article is based on a survey of Personnel Directors in UK universities concerning their perceptions of job sharing. These responses were then used to carry out a cost benefit evaluation of job sharing from the universities' perspective. If productivity of workers in the shared job rose by as little as 0.35 per cent – one third of one per cent – the estimated increase in Personnel Section costs would be covered. If there was a 5 per cent increase in productivity, the ratio of benefits to costs would be 14.3 to 1. Universities also save as a result of greater retention of staff, and there are also important benefits to society, particularly less overall stress and reduced unemployment levels.     

Grouping practices in the primary school: what influences change?

During the 1990s, there was considerable emphasis on promoting particular kinds of pupil grouping as a means of raising educational standards. This survey of 2000 primary schools explored the extent to which schools had changed their grouping practices in response to this, the nature of the changes made and the reasons for those changes. Forty‐eight per cent of responding schools reported that they had made no change. Twenty‐two per cent reported changes because of the literacy hour, two per cent because of the numeracy hour, seven per cent because of a combination of these and twenty‐one per cent for other reasons. Important influences on decisions about the types of grouping adopted were related to pupil learning and differentiation, teaching, the implementation of the National Literacy Strategy, practical issues and school self‐evaluation.     

One School's Experience of Engaging with a Comprehensive Anti-Bullying Programme in the Irish Context: Adolescent and Teacher Perspectives

In this article, the authors report on the evaluation of an anti-bullying programme, the cool school programme (CSP), conducted in a secondary school in Ireland. The study explored how participation in the anti-bullying programme affected students and teachers in one second-level school. The programme focused on students' faith in the teachers' ability to deal with bullying effectively, their willingness and confidence in telling a teacher about bullying and whether they felt safe in school. Teacher confidence and behaviour with regard to bullying were also explored. The study found that 91 per cent of students felt that teachers took bullying seriously. Eighty-nine per cent thought that teachers knew how to deal with bullying and 75 per cent felt able to tell a teacher if they were bullied. Eighty-seven per cent said there was a better atmosphere in their class. Ninety-three per cent of students felt safe in school. Seventy-two per cent of teachers reported greater confidence in their ability to manage bullying and 84% reported increased vigilance. Ninety-four per cent thought that students felt safer in the school. Sixty-nine per cent said there was a better atmosphere in the school. Most felt that the programme was now part of the school culture (94%) and would continue in the school (97%). The authors acknowledge that relying on reported levels of bullying may not give a complete picture of the impact of an anti-bullying intervention. They argue that researchers may need to take into consideration teacher approachability, challenging the culture of silence, responding appropriately and ensuring student safety in school when evaluating programmes.     

Assessment of the English Skills of Tertiary Students

Despite increasing concern about student writing at the tertiary level there has been little empirical research into the nature and extent of the problem in Australia. The writing skills of three samples of university students in different courses were assessed using the multiple choice English Skills Assessment (ESA) test, and two other measures developed by the researchers: a detailed error checklist and wholistic ratings. The error checklist was intended to supplement as well as complement the skills areas covered by the ESA. On average, students responded correctly to 86 per cent of the ESA test items and made a total of 21 errors per 1000 words when writing narrative. The checklist enabled the detection of important deficiencies in writing not identified by the ESA, particularly in some areas of punctuation and sentence structure. Some different emphases are indicated for the testing of writing skills at the university level.     

FINANCING UNIVERSITIES IN CANADA

Underfunding is the paramount problem in Canadian universities. Operating revenue per student has declined in real terms by about 15 per cent over the past 15 years. During the past three decades, revenue from governments has increased from 60 per cent of the total revenue to 80 per cent, while fees revenue has declined from 26 to 16 per cent, with the result that universities are increasingly vulnerable to political control and to financial instability. The transfers of the federal government to provincial governments have financed much of provincial transfers to universities, but the former will be reduced for at least three years and may be abolished altogether. Provincial governments, particularly in Ontario and Quebec, have controlled tuition fees for twenty‐five years in order to increase accessibility, but there has been little change in the socioeconomic composition of university enrollment. Funding for university research generally has neglected overhead costs associated with maintaining the institutional infrastructure necessary for research. Although the federal government still provides more than half of the funding for university research, the share from provincial and non‐governmental sources has been increasing.     

掌浅弓的临床解剖学研究

目的：为手掌血管损伤的修复重建时寻找浅静脉移植修复掌浅弓提供解剖学基础．方法：对54侧成人掌浅弓的类型、形状、对称性和分支进行观察．结果：掌浅弓分5型即尺动脉型、桡尺动脉型、正中尺动脉型、桡正中尺动脉型、尺动脉掌深弓分支型；以尺动脉型和桡尺动脉型为主，正中尺动脉型、桡正中尺动脉型、尺动脉掌分支型少见；有5种形状，弧线形、单弓形多见，不完全形、鞍形、双弓形少见；左右两侧对称性多见，占55．6％．掌浅弓的分支有3—6条，44例发出小指尺掌侧固有动脉，占81．5％．9例小指尺掌侧固有动脉与第3指掌侧总动脉共干，占16．7％．26例发出3条指掌侧总动脉，占48．1％．26例发出4条指掌侧总动脉，占48．1％．结论：手损伤修复重建掌浅弓时应充分注意掌浅弓的分型、形状、对称性和分支．     

THE MINNESOTA TEACHER ATTITUDE INVENTORY

This paper reports on the results of a postal survey carried out basically to examine the nature and extent of usage of mnemonic techniques employed by Psychology students in preparing for finals examinations. Two hundred and five post‐graduates of the Psychology Department at University College, Swansea, i.e. all students who had sat finals papers in Psychology between 1967 and 1971, were sent a questionnaire. The results, based on a response rate of 74 per cent, indicate that 53 per cent of students used mnemonics in examination preparation in order to retain points to be made in essays, 37 per cent repeatedly read material to be retained, 4 per cent claimed they made no attempt to memorize material as such, but rather arrived at an intrinsic understanding of the material. In terms of examination performance there are no significant differences between users and non‐users of mnemonics. This finding does not, therefore, support the view that the use of mnemonics is beneficial to examination performance.     

A New Zealand school counsellor education course viewed by its graduates

An interview follow-up was conducted with a 55 per cent sample of graduates from the first five years of the course for guidance counsellors at the University of Canterbury. The responses indicated, generally, that the course was fulfilling its intended mission. The principal recommendations for change suggested by graduates were more attention to family counselling, consulting methods, power and influence issues, and continuing education. Sixty per cent of the graduates initiated research projects since the course and 72 programme projects, or an average of 3.4 per person, had also been undertaken. Numerous specific applications of concepts and skills taught in the individual papers were reported. Principal professional problems faced by the counsellors were role conflicts, time pressures, isolation, lack of career incentives, lack of credibility and staff support, and lack of influence to initiate programmes and carry out role assignments effectively. Graduates generally felt the course prepared them well for their new counsellor roles. While there was considerable variability in attitudes toward specific papers and topics, the graduates' general attitudes toward the course were favourable.     

An investigation into subtraction

This paper arose from research on numerical errors by 6 and 7 year-olds particularly in subtraction. The present investigation covers four categories: 11 year-olds: school-leavers: student nursery nurses: bus conductor trainees. The central questions were whether earlier errors recurred at these later stages and how far feelings towards the subject (sometimes formed when young) affected performance. The sample was small (N=93) but the results at least suggest questions and directions for further work. In each category, for example, over 25 per cent got a very basic subtraction sum wrong. This indicates that some young children are asked to do sums which are beyond their comprehension and the resulting confusion is difficult to remedy later.