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Role of self-assembly in construction of inorganic nanostructural materials

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中国科学:化学 2012年第11期42卷 1643-1643页

作者： XIONG YanSong 1,2 & TANG ZhiYong 1 1 National Center for Nanoscience and Technology,beijing 100190,china 2 department of Chemistry,Tsinghua university,beijing 100084,china National Center for Nanoscience and Technology beijing 100190 china department of Chemistry Tsinghua university beijing 100084 china

Understanding the evolution process and formation mechanism of nanoscale structures is crucial to controllable synthesis of inorganic nanomaterials with well-defined geometries and unique *** addition to the conventional Ostwald ripening process,oriented aggregation has been recently found to be prevalent in nanocrystal *** this new mechanism,primary small nanocrystals firstly spontaneously aggregate in the manner of oriented attachment,and then the large crystalline materials are formed via the process of interparticle ***,controllable fabrication of the ordered nanocrystal solid materials that has shown specific collective properties will promote the application of inorganic nanocrystal in ***,investigation of the mechanism of oriented aggregation is essential to controllable synthesis of nanocrystals and ordered nanocrystal solid *** this review,we summarize recent advances in the preparation of nanocrystal materials,which are mostly focused on our work about the role of self-assembly in construction of inorganic nanostructural materials.

关键词： inorganic nanocrystal oriented aggregation self-assembly driving forces

环太德塬沟道小流域地貌发育类型及向塬侵蚀趋势研究

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干旱区资源与环境 1989年第3期3卷 112-117页

作者：王卫北京师范大学地理系

本文根据聚类分析结果,提出了研究区地貌侵蚀发育类型划分方案及结果,并进一步进行了向塬侵蚀类型的划分和侵蚀强度的分级。

关键词：侵蚀强度发育类型流域地貌侵蚀类型聚类分析结果沟谷密度平均侵蚀模数黄河中游水保工作发育速度

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社会认知神经科学研究范式述评

心理科学 2010年第5期33卷 1174-1176,1179页

作者：王拥军俞国良刘聪慧中国人民大学心理研究所北京100872 中国人民大学心理学系北京100872

社会认知神经科学是社会科学和神经科学的交叉学科,其研究范式可以概括为三个研究层次和三种研究推论。三个研究层次分别是社会行为层次、信息加工层次和脑神经层次。三种研究推论为把社会行为现象归结为心理机制的心理推论,把心理机制... 详细信息

社会认知神经科学是社会科学和神经科学的交叉学科,其研究范式可以概括为三个研究层次和三种研究推论。三个研究层次分别是社会行为层次、信息加工层次和脑神经层次。三种研究推论为把社会行为现象归结为心理机制的心理推论,把心理机制归结为脑神经机制的机能推论,从心理机制或神经机制中推论社会行为的社会推论。在机能推论中,可以从三个维度区分三类脑神机制,即支持内源性和外源性加工的大脑内侧-外侧结构,支持自动化和控制性加工的大脑腹侧-背侧结构,支持高复杂性和低复杂性加工的大脑前部-后部结构。

关键词：社会认知神经科学心理推论机能推论

Association of DNA with nuclear matrix in in vitro assembled nuclei induced by rDNA from Tetrahymena shanghaiensis in Xenopus egg extracts

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Cell Research 1997年第1期7卷 107-117页

作者： CHEN YING BO ZHANG XIU FEN LI ZHONG HE ZHAI(department of Cell Biology and Genetics, College of Life Sciences, Peking university, beijing 100871) department of Cell Biology and Genetics College of Life Sciences Peking University Beijing 100871On the occasion of Professor Lu Ji SHI's (L. C. Sze) eightieth birthday we present this paper and extend our sincere greetings to Professor SHI. As we mentioned in our paper in early 1950's it is Professor SHI who first studied the behavior of exogenous homologous desoxyribose nucleoprotein (chromatin) in amphibian eggs. His work later led to the study of nuclear assembly in cell-free system. No words can be said too much to describe Professor SHI's achievements in this field. Since the beginning of our research in this field in 1989 Professor SHI always shows high interests in our work exchanges ideas with us and encourages us. We want to express our deep indebtedness to Professor SHI for his many kindness.Received 31March1997 Revised 7May1997 Accepted 6June1997

The nuclei assembled from exogenous DNA or chromatin in egg extracts resemble their in vivo counterparts in many aspects. However, the distribution pattern of DNA in these nuclei remains unknown. We introduced rDNA from the macronuclei of Tetrabymena into Xenopus cellfree extracts to examine the association of specific DNA sequences with nuclear matrix (NM) in the nuclei assembled in vitro. Our previous works showed the 5'NTS (nontranscription sequences) of the rDNA specifically bind to the NM system in the macronuclei. We show now the rDNA could induce chromatin assembly and nuclear formation in Xenopus cell-free system. When we extracted the NM system and compared the binding affinity of different regions of rDNA with the NM system, we found that the 5'NTS still hold their binding affinity with insoluble structure of the assembled nuclei in the extracts of Xenopus eggs.

关键词： Nuclear assembly nuclear matrix Xenopus egg extracts Tetrahymena rDNA

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前向网络的两种混合学习策略

清华大学学报（自然科学版） 1998年第9期38卷 95-97,101页

作者：王凌郑大钟清华大学自动化系

针对前向网络反向传播算法（ＢＰ）训练缓慢和易于陷入局部极小的缺点以及反向运算的复杂性，利用ＢＰ算法监督学习特点、模拟退火（ＳＡ）算法在局部极小处的概率突跳特性和遗传算法（ＧＡ）的并行化群体搜索的特点，有效结合ＢＰ和Ｓ... 详细信息

针对前向网络反向传播算法（ＢＰ）训练缓慢和易于陷入局部极小的缺点以及反向运算的复杂性，利用ＢＰ算法监督学习特点、模拟退火（ＳＡ）算法在局部极小处的概率突跳特性和遗传算法（ＧＡ）的并行化群体搜索的特点，有效结合ＢＰ和ＳＡ算法以及ＧＡ和ＳＡ算法，提出了前向网络的两种混合学习策略即ＢＰ＆ＳＡ混合策略和ＧＡ＆ＳＡ混合策略。以异或问题为例，通过计算机仿真对混合策略与ＢＰ、改进ＢＰ算法的比较表明混合学习策略较大程度改进了前向网络学习的收敛性能和收敛速度，并一定程度上避免了反向运算的复杂性，是前向神经网络学习的有效算法。

关键词：前向网络 BP算法混合策略人工神经网络学习

Theoretical Study on the Structure and Vibrational Spectra for 4-methyl-3-penten-2-one

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Chinese Chemical Letters 1999年第10期10卷 835-838页

作者： Dong Mei DU Ai Ping FU Zheng Yu ZHOU (department of Chemistry. Qufu normal university, Shandong, Qufu 273165 2 State Key Laboratory of Crystal Materials. Shandong university, Shandong, Jinan 250100) Qufu normal Univ Dept Chem Shandong 273165 Qufu Peoples R China Shandong Univ State Key Lab Crystal Mat Jinan 250100 Peoples R China

Density functional theory BLYP (using Becke's and Lee-Yang-Parr's correlation functionals), nb initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibrational spectra of 4-methyl-3-penten-2-one. The BLYP/6-31G* and scaled HF/6-31G* frequencies correspond well with each other and with available experimental assignment of the functional vibrational modes.

关键词： density functional theory vibrational spectra 4-methyl-3-penten-2-one

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汉语及物动词词典中宾语信息的表征

心理学探新 2004年第4期24卷 20-23页

作者：李雪松舒华教育部认知与学习重点实验室北京师范大学心理学院北京100875

该研究利用认知行为反应时方法,操作汉语及物动词与宾语之间的搭配关系,对汉语及物动词词典中宾语信息的表征情况进行了考察。结果发现,随着动词与宾语搭配的语义违反程度的增大,反应时增加。这表明,汉语及物动词词典中存在比较精确的... 详细信息

该研究利用认知行为反应时方法,操作汉语及物动词与宾语之间的搭配关系,对汉语及物动词词典中宾语信息的表征情况进行了考察。结果发现,随着动词与宾语搭配的语义违反程度的增大,反应时增加。这表明,汉语及物动词词典中存在比较精确的宾语信息,其宾语信息是以语义特征来表征的。

关键词：汉语及物动词心理词典宾语信息语义特征语义违反程度

Robust State Estimation for Uncertain Discrete-time Stochastic Systems with Missing Measurements

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Robust State Estimation for Uncertain Discrete-time Stochast...

基于IGBP土地覆盖类型的中国陆地生态系统服务功能价值评估

第二十九届中国控制会议

作者： LIANG Huayong1,ZHOU Tong2 1.department of Automation,Tsinghua university,beijing 100084,P.R.china2.department of Automation and TNList,Tsinghua university,beijing 100084,P.R.china

In this paper,results of robust estimation of [1,2] are extended to state estimation with missing measurements.A new procedure is derived under the estimation framework suggested in [1,2],which is based on penalizing the sensitivity of estimation errors with respect to modelling *** with the existing estimators,a distinguished feature of the new estimator is that it takes completely the same structure as that of the conventional Kalman filter and can be recursively realized without verifying any LMI existence *** attractive property of this estimator is that modelling uncertainties can take an arbitrary structure as long as plant parameters are differentiable with respect to *** simulation results indicate that the proposed estimator even has an estimation accuracy slightly better than the estimator of [7].

关键词： Recursive State Estimation Sensitivity Penalization Date Missing

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山地学报 2004年第1期22卷 48-53页

作者：毕晓丽葛剑平北京师范大学生态研究所北京师范大学生态研究所北京　100875

以国际地圈生物圈(IGBP)所提供的1km2分辨率土地覆盖分类数据和Costanza提出的生态系统服务功能价值,对中国陆地及各省市的生态系统服务功能价值进行评估。结果表明:中国陆地生态系统服务价值为40690亿元。与陈仲新所研究结果相比较,总... 详细信息

以国际地圈生物圈(IGBP)所提供的1km2分辨率土地覆盖分类数据和Costanza提出的生态系统服务功能价值,对中国陆地及各省市的生态系统服务功能价值进行评估。结果表明:中国陆地生态系统服务价值为40690亿元。与陈仲新所研究结果相比较,总体趋势一致,但价值量要小,原因有二:(1)表现为不同时期的中国陆地生态系统服务价值,经济的发展导致生态环境的恶化是生态系统服务价值降低的直接原因;(2)土地覆盖存在着尺度依赖和分类问题,1km2分辨率的土地覆盖可能会忽略那些面积较小但生态价值很高的土地类型,因此使得计算结果偏小。计算出各省市的生态系统价值均能客观的反映该省的生态环境现状。比较分析各省生态系统服务价值及其1997年的国民生产总值(GDP),发现经济相对发达的省市存在环境质量管理与经济快速发展严重的脱节问题,环境承载能力的大大降低应引起人们的注意。归一化植被指数(NDVI)是土地覆盖分类的依据。探讨了各省典型月份的NDVI值与生态系统服务价值之间的关系,回归分析的复相关系数达0.789,证实了土地覆盖评估生态系统服务价值的可行性。由于测量精度问题及估算方法的不成熟,研究得出生态系统服务价值是一个保守的低值估算,有待于进一步的检验和改进。

关键词： IGBP 土地覆盖生态系统服务功能价值 NDVI 中国