自1962年以来比较了17份研究报告后,库珀决定约70%的数据,显示出做功课对学生有积极的影响。该迹象表明,主要的得益来自于坐下来做功课。其余部分的得益是当教练评价及评论所递交的功课。得出的结论是,任何功课总比没有功课更有效。
在决定将来的家庭作业应搭配什么样的目标之前,还有几个相互关联的管理因素应作考虑。其中几个如下:
1)方法和反馈质量,
2)所需的时间来完成(你和他们)的作业,
3)评价的形式及
4)作业有多频密和评价。
~~~~~~~~~纯人手翻译,欢迎采纳~~~~~~~~~。
原文如下:
After comparing 17 research reports since 1962, Cooper determined that approximately 70% of the data showed a positive effect for those students that did homework. The indications are that the major portion of the benefit is derived from sitting down and doing the homework. The remainder of the benefit occurred when the instructor evaluated and commented on the submitted work. The conclusion is that any homework is much more effective than no homework.。
Before deciding what mix of goals to utilize in future homework assignments, there are several inter-related administration factors which should be considered. A few of them are 。
1) method and quality of feedback, 。
2) time required to accomplish (yours and theirs) the assignment, 。
3) type of evaluation, and 。
4) frequency of assignment and of evaluation.。
这里有一座塔,一条从北向南通的小道到塔的西端大概有70米,同样,这里有一条从北流向南的河流达到搭的西端有200米左右.。
PALYGEL PC products scattered 。
1. Waterborne system 。
PALYGEL PC the most common method is to use a small amount of cellulose thickener used in conjunction with. PALYGEL PC concentration of 0.5 - 2.0% (weight), about the amount of cellulose PALYGEL PC usage of 1/4-1/6. 300 by 2.5 percent hydroxyethyl fiber (HEC) or HPMC (HPMC) in aqueous solution with 20 PALYGEL PC's dry powder, and about 70 parts water to mix and stir, can be obtained over a thick pre-dispersed Pulp. This pre-dispersed pulp diluted to paint, you can achieve the desired thickening effect thixotropic. PALYGEL PC can be very good to improve the flow of cellulose-issue, the use of cellulose PALYGEL PC when used with better effect. 。
2. Solvent-based system 。
PALYGEL PC instead of clay used for organic solvent-based system can significantly reduce the cost of paint, selective alternative 50-80%, or even all of the organic clay, according to the different formulation, as the case may be. In the use of solvent-based system, PALYGEL PC need a small amount of cationic surfactant to properly moist and scattered. This surfactant should first join paints, pigments and then join the other components, and fully dispersed after joining PALYGEL PC, and dispersed. Should adopt the best PALYGEL PC and surfactant ratio (5:1 ---- 10: 1), to achieve the best results. Dispersed, can be all kinds of grinding technology. High-speed spread is the most commonly used method, grinding can produce excellent results dispersed. Many customers of 12-20% PALYGEL PC surfactant-gel paste, production can directly join the large number of pre-gel paste ingredients in the paint, without the need to impose high shear, just to fully stirring.。
鄙视 机器翻译- -!o(∩_∩)o...。
Abstract
文摘
Nanosized and highly reactive magnesium niobate (MgNb2O6) powders were successfully synthesized by a new wet-chemical method by means of the dissolution of Nb2O5 5H2O and in a solution of oxalic acid followed by the addition of stoichiometric amounts of magnesium carbonate. 。
纳米和高活性镁铌盐酸(MgNb2O6)成功地合成粉体新wet-chemical手段铟解散,5H2O草酸的溶液中,紧随其后的是增加计量大量的镁碳酸酯。
The Nb–Mg–oxalic acid solution was evaporated resulting in a dry and amorphous powder that was calcined in the temperature range from 200 to 900 8C for 2 h. 。
Nb-Mg-oxalic的乙酸溶液风干导致干燥和无定形的粉末煅烧温度是范围从200到900暖2小时。
The crystallization process from the amorphous state to the crystallineMgNb2O6 was followed by thermal analysis. 。
结晶过程的晶态紧随其后的分别是crystallineMgNb2O6进行热分析。
The calcined powders characterized by FT-Raman spectroscopy, X-ray diffraction (XRD) and their morphology examined by high resolution scanning electron microscopy (HR-SEM). 。
煅烧粉具有FT-Raman光谱、x射线衍射仪(XRD)及其形态对高分辨率的扫描电镜(HR-SEM)。
Pure MgNb2O6, free from the second phases and obtained at 800 8C was confirmed by a combinedanalysis using XRD and FT-Raman. 。
纯MgNb2O6,脱离第二阶段,取得了在800暖combinedanalysis已经证实了用x射线衍射、FT-Raman。
The average diameter of the particles was calculated from the HR-SEM image as 70 nm approximately. 。
平均直径计算出的颗粒HR-SEM大约70海里的形像。
This technique allows a better mixing of the constituent elements and thus a better reactivity of the mixture to obtain pre-reaction products withhigh purity at lower temperatures and reducing cost. 。
这种技术需要一个较好的混合构成要素,从而更好的反应活性这种混合物用来获得pre-reaction产品withhigh纯度维持在较低的温度,降低成本。
It can offer a great advantage in the PMN-PT formation with respect to the solid-statesynthesis. 。
它能提供一个巨大的优势在PMN-PT就solid-statesynthesis形成。
# 2006 Elsevier Ltd and Techna Group S.r.l. 。
出版社有限公司,Techna 2006年号S.r.l组。
All rights reserved. 。
版权所有。
Keywords: MgNb2O6; Columbite; Magnesium niobate; Low temperature synthesis; FT-Raman 。
关键词:MgNb2O6;Columbite、镁铌盐酸;低温合成,FT-Raman。
应该有800电话和网上查询的,价格大约在60-70左右.显示容量是因为硬件商是按1m=1000kb来算的,而电脑是按1=1024计算。