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1.
Alloying is an effective way to manipulate the composition and physico-chemical properties of functional materials. We demonstrated the syntheses of alloyed Co x Ni1?x O nanocrystals using a nonaqueous approach, with x continuously tuned from 0 to 1 by varying the molar ratios of the cobalt precursor in the reagents. The morphological, structural, and compositional properties of the alloyed Co x Ni1?x O nanocrystals were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and energy dispersive X-ray spectroscopy (EDS). The results showed that the cobalt and nickel atoms were homogeneously distributed in the alloyed nanocrystals. The as-prepared Co x Ni1?x O nanocrystals can be applied as the hole-transporting layers in polymer light emitting diodes (PLEDs). Our study provides a good example for the syntheses of alloyed oxide nanocrystals with continuously tunable composition. 相似文献
2.
The synthesis of this molecule was a landmark in organic synthesis. It involved the masterful control of shapes of molecules
to create 9 chiral centres with known absolute and relative configurations. The concepts of absolute and induced asymmetric
synthesis are here explained. 相似文献
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4.
For linear switched system with both parameter uncertainties and time delay, a delay-dependent sufficient condition for the
existence of a new robustH
∞ feedback controller was formulated in nonlinear matrix inequalities solvable by an LMI-based iterative algorithm. Compared
with the conventional state-feedback controller, the proposed controller can achieve better robust control performance since
the delayed state is utilized as additional feedback information and the parameters of the proposed controllers are changed
synchronously with the dynamical characteristic of the system. This design method was also extended to the case where only
delayed state is available for the controller. The example of balancing an inverted pendulum on a cart demonstrates the effectiveness
and applicability of the proposed design methods.
Project (No. 2002CB312200) supported by the National Basic Research Program (973) of China 相似文献
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6.
This paper presents a novel approach to consider optimal multi-degree reduction of Bézier curve with G1-continuity. By minimizing the distances between corresponding control points of the two curves through degree raising, optimal approximation is achieved. In contrast to traditional methods, which typically consider the components of the curve separately, we use geometric information on the curve to generate the degree reduction. So positions and tangents are preserved at the two endpoints. For satisfying the solvability condition, we propose another improved algorithm based on regularization terms. Finally, numerical examples demonstrate the effectiveness of our algorithms. 相似文献
7.
Jing Zhao Shi-wei Li Qian-qian Gong Ling-cui Ding Ye-cheng Jin Jian Zhang Jian-gang Gao Xiao-yang Sun 《Journal of Zhejiang University. Science. B》2016,17(9):657-671
It is widely accepted that body weight and adipose mass are tightly regulated by homeostatic mechanisms, in which leptin plays a critical role through hypothalamic pathways, and obesity is a result of homeostatic disorder. However, in C57BL/6J mice, we found that Rcan2 increases food intake and plays an important role in the development of age- and diet-induced obesity through a leptin-independent mechanism. RCAN2 was initially identified as a thyroid hormone (T3)-responsive gene in human fibroblasts. Expression of RCAN2 is regulated by T3 through the PI3K-Akt/PKB-mTOR-Rps6kb1 signaling pathway. Intriguingly, both Rcan2?/? and Rps6kb1?/? mutations were reported to result in lean phenotypes in mice. In this study we compared the effects of these two mutations on growth and body weight in C57BL/6J mice. We observed reduced body weight and lower fat mass in both Rcan2?/? and Rps6kb1?/? mice compared to the wild-type mice, and we reported other differences unique to either the Rcan2?/? or Rps6kb1?/? mice. Firstly, loss of Rcan2 does not directly alter body length; however, Rcan2?/? mice exhibit reduced food intake. In contrast, Rps6kb1?/? mice exhibit abnormal embryonic development, which leads to smaller body size and reduced food intake in adulthood. Secondly, when fed a normal chow diet, Rcan2?/? mice weigh significantly more than Rps6kb1?/? mice, but both Rcan2?/? and Rps6kb1?/? mice develop similar amounts of epididymal fat. On a high-fat diet, Rcan2?/? mice gain body weight and fat mass at slower rates than Rps6kb1?/? mice. Finally, using the double-knockout mice (Rcan2?/?Rps6kb1?/?), we demonstrate that concurrent loss of Rcan2 and Rps6kb1 has an additive effect on body weight reduction in C57BL/6J mice. Our data suggest that Rcan2 and Rps6kb1 mutations both affect growth and body weight of mice, though likely through different mechanisms. 相似文献
8.
John H. Falk Lynn D. Dierking Nancy L. Staus Jennifer N. Wyld Deborah L. Bailey William R. Penuel 《Cultural Studies of Science Education》2016,11(1):195-212
This paper, describes Synergies, an on-going longitudinal study and design effort, being conducted in a diverse, under-resourced community in Portland, Oregon, with the goal of measurably improving STEM learning, interest and participation by early adolescents, both in school and out of school. Authors examine how the work of this particular research–practice partnership is attempting to accommodate the six principles outlined in this issue: (1) to more accurately reflect learning as a lifelong process occurring across settings, situations and time frames; (2) to consider what STEM content is worth learning; (3) to examine learning as a cultural process, involving varied repertoires of practice across learners’ everyday lives; (4) to directly involve practitioners (and learners) in the research process; (5) to document how existing and emerging technologies and new media are, and will continue, to shape and redefine the content and practice of STEM learning research; and, (6) to take into account the broader socio-cultural–political contexts of the needs and concerns of the larger global society. 相似文献
9.
This paper addresses the accumulating knowledge of prospective teachers of secondary school mathematics and their acquired
proficiency during the course “Psychological aspects of mathematics education,” in which we discussed theoretical models including
the intuitive rules theory. Participants’ performances are examined by means of an extensive report of two episodes, one during
the course and one afterwards. These episodes marked different stages in the prospective teachers’ analysis of their own and
of students’ solutions, which led me to conclude that exposing prospective teachers to the intuitive rules theory is important,
since their familiarity with the theory provided them with a tool to reflect on their own mathematical solutions (subject
matter knowledge; SMK), on others’ solutions, and on the tasks (pedagogical content knowledge; PCK). 相似文献
10.
The selection and design of an optimal solvent for extractive distillation require reliable vapour–liquid phase equilibrium data and knowledge of extraction mechanisms. Compared with time-consuming experiments, molecular simulation presents great potential in research on the properties of fluids. Therefore, in this work, Gibbs ensemble Monte Carlo was applied to successfully predict the vapour–liquid phase equilibrium data of binary and ternary systems containing benzene, thiophene and N, N-dimethylformamide (DMF) at P = 101.3 kPa. The explicit hydrogen version of the transferable potentials for phase equilibria potential model was chosen for benzene and thiophene, whereas the OPLS potential model was selected for DMF. The predicted phase diagrams were compared with experimental data and the UNIQUAC thermodynamic model. A good agreement was obtained, which corroborated the validity of the potential models. In addition, the extraction mechanism was explored by radial distribution function (RDF) of the liquid-phase structure. The RDFs showed that thiophene and benzene shared a similar liquid-phase structure because of the intermolecular interaction. The distinct difference between the RDFs of DMF/benzene and those of DMF/thiophene is that the oxygen atom of DMF is more associated with hydrogen atoms of thiophene than that of benzene, which may be responsible for the extraction effect of DMF. 相似文献
11.
黄丽丽 《淮阴师范学院学报(哲学社会科学版)》2000,22(1):82-86
旧红学家以《左传》为标准评点《红楼梦》,其观点源于金圣叹。《红楼梦》传承于《左传》主要表现在叙述场景安排、人物刻划和艺术表现手法等方面。 相似文献
12.
王晓平 《河北师范大学学报(哲学社会科学版)》2000,23(1):72-76
与我国有着悠久文化交流史的日本 ,对于《诗经》的翻译、改写 ,突出地体现了日本接受中国文化化汉为和、和汉并存的特点 ,日本学者将《诗》不断消化 ,使之融化在日本文化之中 ,形成不似《诗经》的《诗经》变体 ,从《国调周诗》、《诗经国风》及霞朗咏会的汉诗吟诵中可见《诗经》在异文化背景中之命运。 相似文献
13.
常森 《海南师范大学学报(社会科学版)》2000,13(1):112-120
诗歌是历时性的艺术体式之一,这种传统观念,使人们长期忽视对诗的共时性理解。就《楚辞》、《诗经》的研究而言,运用共时性理解可以解开其内容以及形式方面的诸多谜一样的问题,如《离骚》“求女”、《九歌》“事神”、《诗经·桑中》“思孟姜、孟弋、孟庸三人”的真实内涵,《离骚》一诗的多元隐喻模式、其隐喻与转喻的关系,《诗经》的语言形式特征,以及历史“语境”中共时性要素对解读《诗》、《骚》的意义等。共时性理解法与目前流行的那种逸出文本,并最终导致文本整体性消解的所谓文化分析法不同,它主要是文本分析法,重视文本中各相关要素的互相规定作用。 相似文献
14.
论孔子<<春秋>>笔法 总被引：1，自引：0，他引：1
王春淑 《四川师范大学学报(社会科学版)》2000,27(3):76-88
《春秋》笔法是研究《春秋》以及我国古代史籍、史学所不能回避的重要问题之一。前代学者论著不少,但都过于专精而割裂穿凿。今从《春秋》编写实际看,所谓《春秋》笔法是在继承先前史家笔法的基础上发展形成的,是以史事、文辞、史家思想完美统一为根本准则的笔法。 相似文献
15.
林琳 《四川师范大学学报(社会科学版)》2000,27(2):64-70
汲古阁刊《宋名家词》本《竹山词》、明抄《百家词》本《竹山词》与黄丕烈校理本《竹山词》,为《竹山词》传本中最重要的三本.三本各有胜处,而由黄氏所校本得《竹山词》元本目录之全目及其卷中脱佚之篇,由汲古阁本得元人题记之全文,二本价值又在明抄《百家词》本之上.而《历代诗馀》、《词综》、《词谱》、《词律》所采蒋捷词与以上传本文字多相异,于《竹山词》校勘有重要参校价值. 相似文献
16.
张蕾 《河北师范大学学报(哲学社会科学版)》2000,23(1):68-71
《诗经》中的叙事诗表现出有别于西方早期叙事诗的特色 ,一是忽略故事 ,二是极易转向抒情。其成因与先民对于诗歌功能的朴素认识密切相关 ,也反映了我们民族的审美趣味与思维习惯。《诗经》叙事诗的表现手法对于中国古典诗歌重言情轻叙事的创作格局的形成具有一定的影响。 相似文献
17.
徐湘霖 《四川师范大学学报(社会科学版)》2000,27(3):57-63
汉徐幹作《中论》,世有传本。本文作者撰《中论校注》,以清钱培名校补本为底本,又据俞樾《中论札记》等再加以校勘,并加详注,作此《校注》的补记考释一文,以就正于方家。 相似文献
18.
论宋代<<调笑>>词 总被引：2，自引：1，他引：1
彭国忠 《华东师范大学学报(哲学社会科学版)》2000,(2):56-63
宋代《调笑》词有独特的体式,与唐、五代《调笑》迥然不同,它以女性为抒情主体,以男女之间的相爱相悦、相思相别为主要内容。它带有一定的表演性质,是唱赚的早期形式。诗词文三者结合的样式,注重对人物情感心理的刻画,使它具有很强的文学性。它与通俗曲艺接近,但又追求“雅”的风格。宋代《调笑》词集中于北宋,这既与当时的社会文化背景相关,与苏门文人集团的参与创作相关,也是其自身的发展、变化使然。 相似文献
19.
可永雪 《内蒙古师范大学学报(哲学社会科学版)》2000,29(1):57-64
笔者用“从以‘初’字领起到以‘当是时’领起”,“从雅爱趣味到对故事性、戏剧性的追求”,“从单一的叙事体式到多种笔仗并用”三个小标题 ,着重论述《史记》在叙事上对《左传》继承和发展的演进轨迹。 相似文献
20.
陈志勇 《淮阴师范学院学报(哲学社会科学版)》2000,22(2):24-26
我国现行的法律未对外贸代理的性质、代理人的地位等作出规定 ,制约着对当事人权利义务的正确认定和划分 ,也给实际工作带来不少困难。依据新合同法有关委托合同的规定 ,在外贸代理企业以自己的名义与外商签订进出口合同时 ,国内委托单位与外商之间可以发生法律关系 ,在外贸代理企业不公开国内委托单位的存在而以自己名义与外商订立进出口合同的情况下 ,国内委托单位可以行使介入权 ,并对外商承担责任。在外商主张权利时 ,可在外贸代理企业与国内委托单位之间享有选择权。这样做有利于保护当事人各方的合法权益 ,特别是保护处于不利地位一方当事人的权益 ,以体现法律的公正性。 相似文献