超疏水固体表面的形态特征     

陈新华  孟庆祥 《许昌学院学报》2005,24(5):49-57

近年来,超疏水表面(对水的接触角超过150°)由于其在人们的日常生活和生产中潜在的应用价值而引起了人们的广泛关注.固体表面的浸润性是材料的基本特性之一,主要由材料表面的化学成分和微观几何结构共同决定.一般情况下,超疏水表面可以通过两种方法来制备:在疏水性表面构建粗糙结构或者在粗糙表面修饰低表面能物质.由于每种材料的表面能是一定的,所以,控制固体表面的粗糙结构显得更为重要.实验表明:固体表面的微米结构、纳米结构,尤其是微米/纳米相结合的结构能更好地提高固体表面的超疏水性能.  相似文献   

Changes of root morphology and Pb uptake by two species of Elsholtzia under Pb toxicity   总被引：2，自引：1，他引：2  

Peng HY  Tian SK  Yang XE 《Journal of Zhejiang University. Science. B》2005,6(6):546-552

Elsholtzia argyi and Elsholtzia splendens, which are Chinese endemic Pb/Zn mined and Cu mined ecotype respectively, were investigated on the aspect of their response to Pb toxicity in the presence or absence of EDTA addition. After 8 d's Pb treatment, root length, root surface area and root volume of E. splendens decreased much more than those ofE. argyi, and reduced considerably with increase of Pb, while no marked change was noted for root average diameter. Compared to E. argyi, length of root with diameter (D)＜0.2 mm was significantly reduced for E. splendens as Pb increased. D＜0.1 mm E. splendens root had cross-sectional surface area at Pb≥10 mg/L, while for E. argyi, it was at Pb＞25 mg/L. With increase ofPb, DW ofE. splendens decreased much more than that of E. argyi. E. argyi exhibited much more tolerance to Pb toxicity than E. splendens. Treatment with 100 mg/L Pb plus 50 mmol/L EDTA significantly decreased the length and surface area of D≤0.2 mm root, increased the length and surface area of 0.2≤D≤0.8 mm root for the case ofE. argyi, while for E. splendens, length and surface area of D＜0.6 mm root reduced, as compared to 100 mg/L Pb treatment, alone. At 100 mg/L Pb, shoot Pb accumulation in E. splendens and E. argyi were 27.9 and 89.0 μg/plant DW respectively, and much more Pb was uptaken by the root and translocated to the stem ofE. argyi as compared to E. splendens. Treatment of the plant with 100 mg/L Pb plus 50 mmol/L EDTA increased leaf Pb accumulation from 16.8 to 84.9 g/plant for E. splendens and from 18.8 to 52.5 g/plant for E. argyi, while both root and stem Pb pronouncedly reduced for both Elsholtzia species. The increased translocation of Pb to the leaf ofE. splendens being than that ofE. argyi after treatment with 100 mg/L Pb plus 50 mmol/L EDTA should be further investigated.  相似文献   

River morphology and river channel changes     

Howard H. Chang 《天津大学学报(英文版)》2008,14(4):254-262

River morphology has been a subject of great challenge to scientists and engineers who recognize that any effort with regard to river engineering must be based on a proper understanding of the morphological features involved and the responses to the imposed changes. In this paper, an overview of river morphology is presented from the geomorphic viewpoint. Included in the scope are the regime concept, river channel classification, thresholds in river morphology, and geomorphic analysis of river responses. Analytical approach to river morphology based on the physical principles for the hydraulics of flow and sediment transport processes is also presented. The application of analytical river morphology is demonstrated by an example. Modeling is the modern technique to determine both short-term and long-term river channel responses to any change in the environment. The physical foundation of fluvial process-response must be applied in formatting a mathematical model. A brief introduction of the mathematical model FLUVIAL-12 is described. CHANG Howard H, Professor Emeritus.  相似文献   

一种基于形态学和Canny算子的图像边缘提取算法   总被引：1，自引：0，他引：1  

陈荣  刘振亚  刘礼书  饶崧  江延湖 《江西教育学院学报》2008,29(6):14-15

提出了一种基于形态学和Canny算子的图像边缘提取算法。在经过预处理的基础上,运用形态学的开闭运算滤除噪声．局部灰度增强后用Canny算子检测得到清晰的连续的边缘。该算法对噪声有很好的鲁棒性,并得到真正的边缘。  相似文献   

“极平常的,或者简直近于没有事情的悲剧者”——“新时期”小说人物形象的美感形态研究     

孙先科  黄勇 《新乡师范高等专科学校学报》2002,16(3):65-70

生活中的矛盾与冲突更多的时候表现为非对抗性,具有舒缓的性质与状态。应该看到生活中大智大勇、大善大美的英雄遭受毁灭的悲剧,也应该看到不公平、不合理、不理想、不完美带给普通人的摧残、打击与伤害,这或许是更普通的“平常的”悲剧。在“伤痕小说”、“反思小说”等小说思潮中出现的众多的“被污辱与被损害者”、“无辜者”的悲剧形象,在冲突的性质、美感特征、价值形态等方面都同“十七年”文学中和新时期文学初期出现的悲剧英雄标示出明显的不同。“被污辱与被损害的人”是当代中国特殊的政治与文化背景下产生的一批特殊的形象群体。他们不仅在性格特征上自有相似性,而且在美感形态上也自成一体而且独具特征。  相似文献   

A case study on the challenges of learning and teaching English spelling: insights from eight Australian students and their teachers     

Tessa Daffern  Noella Maree Mackenzie 《Literacy》2020,54(3):99-110

  相似文献   

基于人脸识别的人脸图像预处理研究     

刘新业 《沈阳教育学院学报》2008,10(2):83-85

根据人脸图像的特点以及后续处理的要求,主要使用了各种滤波方法对人脸图像进行预处理,进行预处理后的人脸图像利用形态学和BP神经元网络实现识别。实验结果表明取得较好的识别效果。  相似文献   

Reading and spelling error analysis of native     

Salim Abu-rabia  Haitham Taha 《Reading and writing》2004,17(7-8):651-690

This study was an investigation of reading and spelling errors of dyslexic Arabic readers (n=20) compared with two groups of normal readers: a young readers group, matched with the dyslexics by reading level (n=20) and an age-matched group (n=20). They were tested on reading and spelling of texts, isolated words and pseudowords. Two research questions were the focus of this study: What are the reading and spelling profile errors of dyslexic native Arabic speakers? What is the effect of the Arabic orthography on these types of errors? The results of the reading error analysis revealed a clear contribution of the uniqueness of the Arabic orthography to the types of errors made by the three different groups. In addition, the error profiles of the dyslexic readers were similar to the error profiles made by the younger reading-level-matched group in percentages and in quality. The most prominent types of errors were morphological and semiphonetic, which highlighted the contribution of the Arabic orthography to these types of errors. Consistently, the profile of the spelling errors was similar in percentages and quality among the dyslexics and the reading-level-matched group but different from the age-matched group on the spelling measures. The analysis of the spelling errors revealed that the dominant type of error was mostly phonetic due to the limited orthographic lexicon. In addition, the Arabic orthography also contributed to these types of errors because many spelling mistakes were made due to poor knowledge of the spelling rules. The results of the reading and spelling errors are discussed from a reading development point of view. Further, two models are suggested, one for reading and one for spelling, to illustrate the cognitive processes that underlie the reading and spelling mistakes in this type of orthography.  相似文献   

辩证法理论研究综述   总被引：1，自引：0，他引：1  

闫顺利 《江苏广播电视大学学报》2006,17(5)

辩证法是人们耳熟能详的范畴,也是常述常新的问题。辩证法的性质即哲学的性质,故对辩证法问题的探讨本质上是一个哲学观问题。当前,关于辩证法是什么以及辩证法同形而上学的关系问题为学界所热衷,但也歧义纷呈。如何划分辩证法的理论形态、坚持对辩证法的科学态度制约着辩证法理论研究的旨归。  相似文献   

现代汉字构形法在对外汉语汉字教学中的应用策略——对英美学习者的汉字教学     

王颖 《锦州师范学院学报(哲学社会科学版)》2007,29(4):81-84

从现代汉字构形法入手，以格式塔心理学理论与认知心理学理论为理据。提出了现代汉字构形法在对外汉语汉字教学中的应用策略，即从汉英文字构形法的共性开展教学：汉语文字的笔画与英语文字的字母对应教学，汉语文字的部件与英语文字的词根对应教学，汉语文字的整字与英语文字的单词对应教学。这样的教学策略．有利于减少英美学习者对汉字的陌生感，降低学习者的学习难度，提高学习者的学习兴趣，使对外汉语汉字教学取得良好的效果。  相似文献