首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 156 毫秒
1.
油品蒸发与回收综合实验系统设计   总被引:1,自引:0,他引:1  
针对油气储运教学和科研的需要,开发出油品损耗与油气回收综合实验系统。它综合了多种先进技术和实验功能,可测量油品储存和装卸过程中的油品蒸发损耗,并可通过活性炭吸附法和常温常压吸收法对蒸发排放油气进行回收处理和性能测试。该系统技术先进、功能全、综合性强,更有利于锻炼和提高学生的专业技能,培养学生的综合能力和科研素质,  相似文献   

2.
介绍了燃煤电厂发电全过程,分析各个发电过程可能造成能源低效的原因.系统分析了出现能源量损耗的分布,以及其中影响煤炭能源利用率的主要影响因素.通过对损耗的分析,建立了一套能够评价每一阶段能源效率的效率指标体系,并以此来综合评价能源利用效率,对燃煤电厂的发电过程进行分析.  相似文献   

3.
学校实验室精密仪器设备一般都配备稳压器,以保证仪器的正常使用,然而稳压器的能源损耗是一大浪费。如何降低稳压器的能源损耗,让市电在安全电压范围内时,使稳压器自动脱离电源,将市电直接供给负载,消除稳压器自身损耗;负载为零时,也使稳压器自动脱离电源,消除其空载损耗,让稳压器的能源损耗降至最低,又能发挥稳压器应有的作用,经试制,达到了设计功能。  相似文献   

4.
利用油品蒸发损耗及油气回收测试平台,实测了油罐不同装油速度、装油口高度和罐内气体空间初始油气浓度对油气浓度、损耗率以及气液比的变化规律.结果表明,低装油口装油时,液面上升速度为0.371~0.557 mm/s,对油气浓度影响不大;当液面上升速度为0.371~1.114 mm/s时,高装油口装油时损耗率为2.45‰~4.00‰,而低装油口装油时损耗率为1.08‰~2.09‰;当液面上升速度为0.557~1.114 mm/s时,低装油口装油时的气液比为1.13~1.30.研究结果对现实生产管理有重要的指导意义,可为降低油品蒸发损耗、减少环境污染提供依据.  相似文献   

5.
在石油储运过程中,石油中一部分较轻的组分常常逸人大气,发生油气蒸发损耗,造成损失。为了有效减少油罐内轻质油品的蒸发损耗,应严格控制油品温度及其变化。通过对油罐的几何特性的分析,在求解边界条件时充分考虑大气温度变化、油品初始温度以及油罐顶部对流条件等诸多影响因素的基础上,建立了轻油温度场三维非稳态热传导模型,并使用ANSYS有限元软件求解了该数学模型和对油罐内轻油温度场进行了模拟计算。以广东茂名地区某一油罐为例,设定每个季度为一个周期,模拟了该油罐一年内的轻油温度场,可以求解出在运行周期内某时刻轻油温度场的温度分布,也可以求解出油罐内任意点在整个运行周期中的温度变化情况。  相似文献   

6.
研制了油品小呼吸蒸发损耗实验装置。实验结果表明,此装置结构紧凑、测试手段完善、操作安全方便、实验效果良好,理论计算与实际测量误差小于10%,有助于提高工作人员的理论分析能力和实践操作技能。  相似文献   

7.
研制了油品小呼吸蒸发损耗实验装置。实验结果表明,此装置结构紧凑、测试手段完善、操作安全方便、实验效果良好,理论计算与实际测量误差小于10%,有助于提高工作人员的理论分析能力和实践操作技能。  相似文献   

8.
学时,又称教时、课时,是学校进行课堂教学的时间计量单位,它是由若干更短小的时段构成的.学时结构就是这些更小时段相互关联的总和.学时损耗包括显性损耗和隐性损耗两种.显性损耗是指教师迟到、早退、处理偶发事件以及与教学内容无关的说教等时间的损耗;隐性损耗则是由于学时结构组织安排不合理所造成的学时损耗.学时的显性损耗随着教师素质的提高而日趋减少和避免,可学时的隐性损耗却为许多教师所忽略.因此,减少学时的隐性损耗是提高课堂教学效率的重要方面之一.  相似文献   

9.
在能源消耗系统中,锅炉及供热系统占有很大比例。据不完全统计年耗煤量约占我国煤炭产量的三分之一左右。煤炭是我国的主要能源,在我国能源结构中占有相当大的比重,因而提高锅炉的热效率,降低锅炉及供热系统的热损耗,节约能源,是我国能源供需之间的不平衡得到缓解是一项十分重要的任务。  相似文献   

10.
社会生产生活发展迅速,对电力能源的需求不断增大,而电厂作为电力能源生产主要对象,其生产经营一直都是国家关注的重点。基于可持续发展理念,需要对电厂原有生产系统进行优化,尤其是热力系统作为重要部分,需要采取措施进行节能减排优化,减少能源的损耗,提高生产综合效益。文章结合电厂热力系统特点,对其节能减排措施的实施进行了简要分析。  相似文献   

11.
功率因数的高低关系到输配电线路、设备的供电能力,也影响其功率损耗。采用无功补偿可提高功率因数、节约电能、减少运行费用、降低损耗,符合我国节约能源的政策。  相似文献   

12.
通过对带弹性滑动的分析,说明弹性滑动对带的传动比、传动功率损耗的影响。  相似文献   

13.
生物标本的保存与维护   总被引:2,自引:0,他引:2  
重点介绍生物标本在保存过程中应用采取的相应措施及方法,降低损耗,保证生物标本的美观实用。  相似文献   

14.
Using a multilevel, integrative approach, this paper shows the possibility and desirability of modelling both science learning products and processes simultaneously within an educational structure and specific learning context. Questions of inequality and inequity of science teaching and learning at the Sixth Form (grade 12) level in Hong Kong are answered within the confines of (1) the aims of Sixth Form education and (2) the related issue of educational wastage. From the comparative science education perspective, this comprehensive study would provide some insights regarding science learning contexts and processes for researchers to reflect why Hong Kong was found to rank amongst the top positions in physics, chemistry and biology in the IEA Second International Science Study.  相似文献   

15.
MSC1201型微处理器具有与8051型微处理器完全兼容的内核,执行速度更快,功耗更低.本文详细介绍基于此电路并配合ADI的AD590型温度传感器的温度控制系统的设计与实现.  相似文献   

16.
不同质子酸掺杂聚苯胺的吸波性能研究   总被引:3,自引:0,他引:3  
采用3厘米波导式测量线在8—14GHz频率范围内,用多点拟合的实验和计算方法对掺杂聚苯胺的微波吸收特性及参量进行了研究.发现:浓H2SO4掺杂本征态聚苯胺(PAn)所合成材料的电损耗很小、磁损耗较大(相对于盐酸聚苯胺而言),且不利于对微波的吸收:FeCl3掺杂浓H2SO4-PAn材料可合成磁损耗较高、基本上有利于吸收微波的材料;更令人注意的是,利用HCl-PAn具有较大的电损耗,浓H2SO4-PAn—FeCl3材料具有较大的磁损耗这一特点,我们将它们按一定的比例混合,可以合成出平均衰减为13.37dB,最大衰减为26.7dB,密度为0.7g/cm^3、频宽为10.34—14GHz的很有利于吸收微波的材料.  相似文献   

17.
蓝牙技术是一种低成本、近距离、低功耗的无线通信标准,它为实验仪器设备提供了一种无线连接方式。本文总结了蓝牙技术主要特点,分析了它的拓扑结构,提出了实验室教学应用模型,探讨了蓝牙技术在实验室中的的应用。  相似文献   

18.
Summary

  • 1.Wastage is a characteristic of all forms of further education, full-time and part-time.

  • 2.Wastage can be defined in more than one way, and the severest definitions obviously include amongst the wastage many students who have benefited from their participation in further education.

  • 3.Failure rates from first to final year in English Universities are at least 10 per cent on the average, to which have to be added the group—some 5 per cent—who withdrew for reasons other than academic failure. This gives an average total wastage of 15 per cent, from first to final year.

  • 4.Even in the relatively superior conditions of university life and teaching, precise prognostication is not possible; therefore, either some failures must be admitted or some who would succeed must be excluded. To eliminate failures altogether would mean applying selection procedures that would exclude large numbers of those who now succeed.

  • 5.Wastage is a product of multiple causation. Hence, there are no simple or sweeping remedies. On the other hand, such success as is achieved remains unknown because it is not recorded and published.

  • 6.Wastage in technical education can be classified into three sorts: natural, built-in and imposed.

  • 7.Natural wastage is largely, if not entirely, irremediable (in the given conditions). It is valuable to identify it, important to estimate its size and sensible to devote to other causes efforts to improve the situation. It seems likely that natural wastage amounts to something like 25 per cent of the entrants to a five year part-time course—although there is no evidence of a convincing kind to support any particular figure.

  • 8.Built-in wastage is a feature of part-time technical courses. It could very easily be much reduced. The place to begin is with craft courses which are not hedged in by so many Rules and such powerful vested interests as are the National Certificates. The steps to take are simple, and are within the competence of Principals and Heads of Department. The examination results now available annually should be used differently; in particular, the results in the ‘noncrucial’ years should not, in general, preclude students from passing on to the next year of the course. Gross built-in wastage on the average five-year course amounts to 70 per cent or so, having allowed an off-set for students who repeat a year.

  • 9.It will be seen that 70 per cent built-in wastage plus 25 per cent natural wastage amounts to 95 per cent wastage over a five-year course. A success rate of 5 per cent in such courses is often exceeded—it may rise to 25 per cent, but a success rate even lower is by no means unknown, though the recording of some such instances by Lady Williams appears to have shocked many of her readers.

  • 10.The advantage of going through a course may be quite real to a student who does not gain a certificate. Presumably this is truer of craft courses than of other courses.

  • 11.Imposed wastage is remediable to some extent, though not perhaps as completely as might be hoped. At present there is much emphasis on selection, and it is most desirable that selection procedures should be improved.

  • 12.Even more important as an antidote to imposed wastage is an improved teaching force: improved in numbers and quality. This is not to say that teaching in technical colleges is bad—far from it. There always have been excellent teachers in technical colleges and their numbers have grown hearteningly since 1945. Nor is it to say that the need is for more graduates or more teachers with second degrees—although such are most welcome. What is needed is greater total numbers of teachers and far more whose main interests are in their pupils, in the difficulties of their pupils, in teaching rather than in scholarship. Senior lecturers promoted to that position because they are good teachers, because they are educationists, are more important to a college than those elevated on the strength of the letters after their names. Both kinds are valuable. Some splendid fellows are themselves of both kinds.

  • 13.In approaching any particular problem of wastage, it is necessary to know, or to estimate, how much is natural, how much built-in, how much imposed. Obviously the built-in wastage figure needs breaking down. It includes the out-and-out duds and slackers, a small number, probably no more than 2 per cent or 3 per cent over a five-year wastage of 70 per cent. It includes also the weak and doubtful who just don't make the grade—perhaps 7 per cent or 8 per cent more. And it includes a fair number affected by imposed wastage in its many forms—perhaps 25 per cent. The breakdown in a five-year wastage of 95 per cent in a part-time course might then take the form:

Where wastage in such a course amounts to 75 per cent of the first-year entrants, and on the assumption that natural wastage is at the same rate in all such courses, the total wastage might be classified as follows:

No validity is claimed for these figures. They are presented to sharpen the idea that an attack on wastage can only be made if it is known what is being attacked. For example on this analysis, in a five-year course with 75 per cent wastage, improved selection could only hope to affect a proportion of the imposed wastage plus the weaklings, i.e. a proportion of 25 per cent of the total wastage of 75 per cent. A somewhat higher proportion of this 25 per cent wastage could probably be prevented by improved teaching.

  • 14.The need for enquiries and research into these problems is acute. Much information is available, and ready for analysis. On the other hand, on some problems nothing at all has been done and no information exists. For instance, no college, so far as is known, has systematically followed up the part-time students of one year who do not enrol for a succeeding year. Such an enquiry, done over one or two typical National Certificate and craft courses might be illuminating.

  • 15.The price paid for a part-time system of education includes a high wastage rate. As long as part-time education goes on, wastage will be very high. As a route to a major qualification—professional or craft—part-time education is a wasteful anachronism; in its purely evening form it should be abolished immediately.

  相似文献   

19.
中小型民营企业人才流失探讨   总被引:2,自引:0,他引:2  
人才流失问题严重影响中小型民营企业的生存和发展。人才流失将给企业发展带来重置成本高、无形资产流失、冲击员工心理等危害。民营企业必须积极寻找控制民企人才流失的路径。  相似文献   

20.
论述了目前我国高校在科研经费管理中存在的主要问题是管理不到位、支出不合理、固定资产流失等;分析了产生的原因;针对这些问题提出几点建议。指出高校应成立科研经费管理领导小组、完善管理制度、严格固定资产购置程序、加强监督检查等,真正最大限度地发挥科研经费的作用。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号