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1.
Antifreeze     
《中学科技》2009,(12):26-26
An antifreeze is a liquid that is added to water to keep it from freezing. When water freezes and turns into ice, it expands. The force of water expanding is so great that it will break the hardest metal. Water is used in car engines to keep them cool while they run, and if this water is allowed to freeze in the winter, it can break the iron block of the engine. That is why antifreezes are necessary.  相似文献   

2.
Most of us are used to the fact that skirts are basically worn by human females. We do not realize that Scotland is the land that has skirts traditionally worn by men and boys. It is, indeed, a practice of the Scottish male not to be embarrassed when he wears the Scottish kilt , which is actually a beautiful skirt.Long ago, in the land, it was common for Scottish men and boys to use skirts. It was mainly male performers that used them. The practice spread far and wide. Later, it gained favour with the Scottish royalty, especially when kilts were used by the Scottish male bagpipers at court. A bagpipe is a blowing instrument.The Scottish kilt is one of the national of Scotland. Therefore, it is not uncommon to see in Scotland a male using it on himself and feeling proud of it.  相似文献   

3.
With the flooding of pornographic information on the Internet, how to keep people away from that offensive information is becoming one of the most important research areas in network information security. Some applications which can block or filter such information are used. Approaches in those systems can be roughly classified into two kinds: metadata based and content based. With the development of distributed technologies, content based filtering technologies will play a more and more important role in filtering systems. Keyword matching is a content based method used widely in harmful text filtering. Experiments to evaluate the recall and precision of the method showed that the precision of the method is not satisfactory, though the recall of the method is rather high. According to the results, a new pornographic text filtering model based on reconfirming is put forward. Experiments showed that the model is practical, has less loss of recall than the single keyword matching method, and has higher pr  相似文献   

4.
Dear Sir or Madam:I am writing in regard to your notice about the delay in shipment of my order for 14 dozen Olympic quality,ultra accurate,gold tip arrows.Perhap you do not understand the urgency of the situation.I re-alize that you have no control over the suppliers of your stock;however,surely you have an existing supply in your warehouse.As a valid customer for so many years,I appeal to you to consider filling my order ahead of any others.Since Valentine's Day will fall on the 14th day of February.as traditional,it is imperative that my order be received no later than the 13th.I must be ready for my flight early the next morning in order to assure that couples the world over are not disappointed.Without equipment,I am powerless and love cannot be delivered to those in need  相似文献   

5.
A new all-zero block determination rule was used to reduce the complexity of the AVS-M encoder. It reuses the sum of absolute difference of 4x4 block obtained from motion estimation or intra prediction as parameters so that the determination threshold need to be computed only once when quantization parameter (QP) is invariable for given video sequence. This method avoids a lot of computation for transform, quantization, inverse transform, inverse quantization and block reconstruction. Simulation results showed that it can save about 20%~50% computation without any video quality degradation.  相似文献   

6.
Few students know that grammar is acquired naturally;it need not be taught.Grammar is often misunderstood in the language teaching.There are some students thinking it a waste of time to memorize the rules.They even claim that if the structures are taught,the lessons will be boring.This paper will help to realize how helpful and useful as well as beneficial learning English grammar well will be,not only for students,but also for teachers.  相似文献   

7.
In this work, image feature vectors are formed for blocks containing sufficient information, which are selected using a singular-value criterion. When the ratio between the first two SVs are below a given threshold, the block is considered informative. A total of 12 features including statistics of brightness, color components and texture measures are used to form intermediate vectors. Principal component analysis is then performed to reduce the dimension to 6 to give the final feature vectors. Relevance of the constructed feature vectors is demonstrated by experiments in which k-means clustering is used to group the vectors hence the blocks. Blocks falling into the same group show similar visual appearances.  相似文献   

8.
A color-intensity feature extraction method is proposed aimed at supplementing conventional image hashing algorithms that only consider intensity of the image. An image is mapped to a set of blocks represented by their dominant colors and average intensities. The dominant color is defined by hue and saturation with the hue value adjusted to make the principal colors more uniformly distributed. The average intensity is extracted from the Y component in the YCbCr space. By quantizing the color and intensity components, a feature vector is formed in a cylindrical coordinate system for each image block, which may be used to generate an intermediate hash. Euclidean distance is modified and a similarity metric introduced to measure the degree of similarity between images in terms of the color-intensity features. This is used to validate effectiveness of the proposed feature vector. Experiments show that the color-intensity feature is robust to normal image processing while sensitive to malicious alteration, in particular, color modification.  相似文献   

9.
Webwatcher     
Link sitesThese are sites that are mainly useful for the links they provide to other sites.www. bized. ac. uk/Keep in mind that the site is not designed specifically for ELT students, but it does cater for younger learners and much of the material would be appropriate. You will need to do quite a lot of searching, but there are plenty of articles to read  相似文献   

10.
EAP refers to the language and associated skills that students need to undertake study in higher education through the medium of English. EAP is a branch of ESP * in that the teaching content is matched to the learners requirements (Robinson, 1991, pp. 2-5): EAP is goal directed - students learn Enligsh because they need it. EAP courses are based on needs analyses - which specify clearly what students have to do in English (but see: Benesch, 2001). Most EAP courses are fixed term - short presessional courses are fixed term - short presessional courses or longer foundation courses - in preparation for academic courses. Students may need specialist language, but not necessarily - courses are defined by the activities the students will engage in. A very high level of proficiency may not be required -  相似文献   

11.
The ZM-1 tissue microarrayer designed by our groups is manufactured in stainless steel and brass and contains many features that make TMA (tissue microarray) paraffin blocks construction faster and more convenient. By means of ZM-1 tissue microarrayer, biopsy needles are used to punch the donor tissue specimens respectively. All the needles with the punched specimen cylinders are arrayed into the array-board, with an array of small holes dug to fit the needles. All the specimen cylinders arraying and the TMA paraffin block shaping are finished in only one step so that the specimen cylinders and the paraffin of the TMA block can very easily be incorporated and the recipient paraffin blocks need not be made in advance, and the paraffin used is the same as that for conventional pathology purpose. ZM-1 tissue microarrayer is easy to be manufactured, does not need any precision location system, and so is much cheaper than the currently used instrument. Our method's relatively cheap and simple ZM- 1 tissue microarrayer technique of constructing TMA paraffin block may facilitate popularization of the TMA technology.  相似文献   

12.
The ZM-1 tissue microarrayer designed by our groups is manufactured in stainless steel and brass and contains many features that make TMA (tissue microarray) paraffin blocks construction faster and more convenient. By means of ZM-1 tissue microarrayer, biopsy needles are used to punch the donor tissue specimens respectively. All the needles with the punched specimen cylinders are arrayed into the array-board, with an array of small holes dug to fit the needles. All the specimen cylinders arraying and the TMA paraffin block shaping are finished in only one step so that the specimen cylinders and the paraffin of the TMA block can very easily be incorporated and the recipient paraffin blocks need not be made in advance, and the paraffin used is the same as that for conventional pathology purpose. ZM-1 tissue microarrayer is easy to be manufactured, does not need any precision location system, and so is much cheaper than the currently used instrument. Our method's relatively cheap and simple ZM-1 tissue microarrayer technique of constructing TMA paraffin block may facilitate popularization of the TMA technology. Project (No. G1998051200) supported by the National Basic Research Program (973) of China  相似文献   

13.
根据两条B样条曲线低分辨表示部分的大小关系在JPEG压缩下较稳定的特点提出了一种用于图像认证的半脆弱数字水印方法。产生一个依赖于原图像内容的水印,将图像进行8×8分块,并分为两组,在每一组中分别取一个分块,选择特定点的像素值作为控制顶点,构造B样条曲线,对B样条进行多分辨分解,通过修改两条B样条曲线低分辨表示部分的大小关系嵌入水印。该算法可以检测并定位被修改的位置,可用于图像的完整性认证,并有一定的抗压缩能力。  相似文献   

14.
基于冲突图模型形成的二进制整数规划,提出了一种蜂窝网络中支持D2D通信的无线资源分配方法.首先,提出一种频率资源分配算法,即为每个D2D链路都分配一个频率资源块.分配频率资源时将尽可能地利用蜂窝网络中的无线频率资源空间重用机会.然后,提出一种时隙调度算法,即为所有分配同一频率资源块的D2D链路进行时隙资源调度.调度时隙资源时将保证使用同一频率资源块的D2D链路之间达到长期平均吞吐率的比例公平.通过计算机仿真对所提出方法的性能进行了验证,结果表明该方法能够在蜂窝网络中实现D2D通信功能.  相似文献   

15.
基于样图的纹理合成基本思想是根据给定的小区域的纹理样本,拼合生成任意大小的纹理图像并且在视觉上与样本是相似而连续的。通过对基于样图的纹理合成算法进行研究,在待合成纹理块的搜索策略上,提出优先搜索前一个已合成纹理块在样图中的位置附近,快速定位下一个用于合成的纹理块。在纹理块的匹配策略中引入小波变换,结合小波变换后的小波系数和小泼变换后的低频域图像进行块的重叠区域匹配,最后使用最小路径法将待合成纹理块缝合到输出图像中。充分考虑了样图的结构信息并提高了合成速度,获得了较好的纹理合成效果。  相似文献   

16.
利用TMA/HPA技术,可以从1或2.5个细胞当量中探测出端粒酶的活性。其探测范围大于传统的TRAP技术。并且,当样品抽提取被稀释剂≤1μg蛋白时,未用酚-氯仿处理过的TMA/HPA给出的信号与用其处理过而给出的信号是相同的。说明在低浓度蛋白的临床样品中,该技术几乎不受TRAP抑制因子的作用。当含有1μg或0.1μg蛋白时,在33个从肝脏中提取出的组织样品中,有27个给出阳性信号,阳性比率为81.8%,说明TMA/HPA的灵敏度较高。  相似文献   

17.
Two studies were conducted on block building in adolescents, assessing middle school (Study 1) and high school students (Study 2). Students were asked to build something interesting with blocks. In both samples, the same pattern of gender differences were found; boys built taller structures than girls, and balanced a larger number of blocks on a small base of upright blocks (a new measure developed for this study). Gender differences in the height of structures were fully mediated by this measure of structural balance. These findings suggest that balance elements are key to understanding gender differences in block building. In Study 2, high-school students were given a second task, requiring them to apply structural balance principles (only four upright blocks were provided on which to build), and instructing them to build a tall, complex, well-balanced structure. Gender differences again were found, suggesting that gender differences in block building may be skill-based as well as stylistic. A separate question was whether block-building characteristics at this age have any relevance to math achievement. In both studies, the measure of structural balance was the only block-building characteristic that predicted math achievement. Additional research is needed to understand the cognitive underpinnings of this new spatial measure, how malleable it is, and its further practical significance for adolescent learners.  相似文献   

18.
作为New ton多项式插值在重节点情形时的推广,New ton-Hermite多项式插值是很常用的切触线性插值,它建立在广义差商基础之上,广义差商能被递归地计算并产生有用的中间结果。New ton-Hermite插值实际上是基于点的插值,可以通过增加新的节点来获得一个新的插值多项式。这里将基于点的插值推广到基于块的插值。受现代建筑设计的启发,将插值点集划分为一些子集(块),然后将在每个子集上选择切触插值,线性或有理插值,最后用类似于New ton-Hermite插值的格式进行装配。显然,在切触有理插值上提供了灵活的选择,这里也包括它的特殊情形New ton-Hermite多项式插值。本文介绍了所谓的基于块的广义差商并给出递归算法,给出的数值例子说明了方法的有效性。  相似文献   

19.
Sequence placement logic plays a significant role in construction simulation of high arch dams and directly affects the simulation process and results. To establish a sequence logic for dam block placement, the construction scheme, real-time construction process, and random factors of the site all need to be considered in detail. There are few studies available currently that take all these factors into consideration. To address this problem, a real-time update of sequence placement logic for high arch dams based on evidence weight discount is proposed in this study. First, the subjective weight of the dam block sequence priority criteria is built using a consistent matrix method based on the construction scheme. Second, using evidence theory, dynamic objective weight of the priority criteria and basic probability assignment is built. Finally, using a weight self-adaptive adjustment method and comprehensive evidence discounting, the placing probabilities of different dam blocks are obtained. A case study indicates that this method can realize real-time update of sequence placement logic.  相似文献   

20.
提出一个基于区块差值分布之彩色BMP图文件可回复信息隐藏法,先将彩色BMP图档的像素切割成不重迭长宽各3个像素的区块,每个区块中用特定方式选择其中一个像素,计算其他8个像素和此像素的RGB颜色绝对差值,利用这些差值来产生分布图,在分布图中找出适合的峰点和零点,将峰点和零点内的区域向右位移1个颜色差值,就能将位形式的信息藏入峰点颜色差值的像素中,藏入信息的图文件仍能保持良好质量,肉眼无法察觉差异,经实验证明本研究提出的方法可隐藏大量信息并维持良好的图片质量。  相似文献   

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