The conformation of side-chain liquid crystal polymers with different mesogen-graft amounts has been studied by small-angle neutron scattering in dilute solutions of toluene-d8 and THF-d8. It is shown that the radius of gyration increases by about twofold when the mesogen-graft amount increases from 0 to 100%, which suggests that the persistence length of the backbone increases by about 4-fold. Comparison with the results reported in the literature on the melt state suggests that the persistence length is not an intrinsic property of side chain liquid crystal polymers, but depends on inter-chain interactions. 相似文献
This research was designed as an initial attempt to assess relational aggression in preschool-age children. Our goal was to develop reliable measures of relational aggression for young children and to use these instruments to address several important issues (e.g., the relation between this form of aggression and social–psychological adjustment). Results provide evidence that relationally aggressive behaviors appear in children's behavioral repertoires at relatively young ages, and that these behaviors can be reliably distinguished from overtly aggressive behaviors in preschool-age children. Further, findings indicate that preschool girls are significantly more relationally aggressive and less overtly aggressive than preschool boys. Finally, results show that relational aggression is significantly related to social–psychological maladjustment (e.g., peer rejection) for both boys and girls. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Two experiments were conducted to assess how children who differ in vocabulary knowledge learn new vocabulary incidentally from listening to stories read aloud. In both experiments, 4-yr-old children were classified as having either high or low word knowledge on the basis of a median split of their Peabody Picture Vocabulary Test—Revised (PPVT—R) standard scores. In Exp 1, children either listened passively or labeled pictures using novel words during the book readings. We found that children with larger vocabularies produced more novel words than did children with smaller vocabularies, and children who answered questions during the book readings comprehended and produced more words than did children who passively listened to the story. In Exp 2, children either listened to readings of a book, pointed to pictures during the readings, or labeled pictures during the readings. Children with larger vocabularies comprehended more novel words than did children with smaller vocabularies. Children who actively participated by labeling or pointing learned more words than did children who listened passively to book readings. Findings clarify the role of active responding by demonstrating that verbal and nonverbal responding are effective means of enhancing vocabulary acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Examines the time course of lexical access in written-word recognition by comparing words with early and late uniqueness points (UPs). Three experiments, which used a normal (simultaneous) presentation of the letters under 3 different tasks (gender classification, naming, and semantic classification) provided no evidence for sequential processing. Rather, a small advantage in favor of words with late UP was found, which may be interpreted in terms of the lower n-gram frequencies of early-UP words. Exp 4 supported this interpretation and discussed an alternative interpretation in terms of parafoveal preview of the initial letters. A last experiment, which used an incremental presentation of the word letters, gave rise to a UP effect comparable in size to that obtained in an auditory study, suggesting that a temporal distribution of the signal is a sufficient condition for directional processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
The solution to elastic isotropic problems in three-dimensional (3-D) polyhedral domains in the vicinity of an edge is provided
in an explicit form. It involves a family of eigen-functions with their shadows, and the associated edge stress intensity
functions (ESIFs), which are functions along the edges. Utilizing the explicit structure of the solution in the vicinity of
the edge we use the quasidual function method, recently presented in [Omer et al. (2004). International Journal of Fracture129:97–130] for scalar elliptic problems and in [Costabel et al. (2004). SIAM Journal of Mathematical Analysis35(5), 1177–1202] in a general theoretical framework, for the extraction of ESIFs. This method provides a polynomial approximation
of the ESIF along the edge whose order is adaptively increased so to approximate the exact ESIF. It is implemented as a post-solution
operation in conjunction with the p-version finite element method. Numerical examples are provided in which we extract ESIFs associated with traction free or
homogeneous Dirichlet boundary conditions in 3-D cracked domains or 3-D V-Notched domains. These demonstrate the efficiency,
robustness and high accuracy of the proposed quasi-dual function method. 相似文献
This paper aims at identifying some of the key factors in adopting an organization-wide software reuse program. The factors are derived from practical experience reported by industry professionals, through a survey involving 57 Brazilian small, medium and large software organizations. Some of them produce software with commonality between applications, and have mature processes, while others successfully achieved reuse through isolated, ad hoc efforts. The paper compiles the answers from the survey participants, showing which factors were more associated with reuse success. Based on this relationship, a guide is presented, pointing out which factors should be more strongly considered by small, medium and large organizations attempting to establish a reuse program. 相似文献
An investigation was conducted in five companies in the distribution branch. These companies were divided into three different working systems, i.e., highly mechanized (HM), moderately mechanized (MM), and slightly mechanized (SM). The three systems differed in logistics and kind of appliances used. The purpose of this study was to compare the three working systems with different degrees of mechanization concerning the time spent on tasks, activities during the working day, postures that occurred, physiological work load, perceived exertion and recovery from work. To investigate the different tasks, activities and working postures, 50 warehouse workers, originating from the three working systems, were observed by means of a direct observation method, called: ‘TRAC’. To investigate the physiological work load the heart rate was recorded continuously during the working day and related to the individually determined relation between heart rate and oxygen uptake. This relation was constructed with the results of a cycle ergometer test done in the laboratory. During lunch and at the end of the working day the warehouse workers filled in a questionnaire concerning their perceived exertion and recovery from work.
In the slightly mechanized system more time was spent with the trunk flexed more than 75° as compared with the other two systems. This posture was very common during lifting of objects, and lifting was done more often in this system than in the other systems. In the MM system the warehouse workers had the highest estimated oxygen uptake and reported the highest perceived exertion at the end of the working day. The workers in the HM system had a shorter working day and had less problems with recovery from work than the workers of the other two systems. Poor working postures like rotation and lateroflexion were commonly found in the HM working system. An important explanation was the difference in time spent driving an electric car. This activity was done mostly in the HM system. In conclusion, the HM system was considered most favourable when it concerned work load and recovery from work. The appliances used in the HM system, and especially the electric car, need to be designed according to ergonomic guidelines to avoid poor working postures. 相似文献
Enterprises are living things. They constantly need to be (re-)architected in order to achieve the necessary agility, alignment
and integration. This paper gives a high-level overview of how companies can go about doing ‘enterprise architecture’ in the
context of both the classic (isolated) enterprise and the Extended Enterprise. By discussing the goals that are pursued in
an enterprise architecture effort we reveal some basic requirements that can be put on the process of architecting the enterprise.
The relationship between managing and architecting the enterprise is discussed and clarified in the FAD(E)E, the Framework
for the Architectural Development of the (Extended) Enterprise.
Frank G. Goethals completed his Master studies in economics (option informatics), at the Katholieke Universiteit Leuven, Belgium, in 2000.
He is presently researching for a Ph.D. under the theme of `Managing data in the Extended Enterprise'. This research is conducted
at the K.U.Leuven under the guidance of professor J. Vandenbulcke, and is financed by SAP Belgium. Frank has a strong interest
in coordination and dependency theory and Enterprise Architecture.
Monique Snoeck obtained her Ph.D. in May 1995 from The Department of Computer Science of the Katholieke Universiteit Leuven with a thesis
that lays the formal foundations of the object-oriented business modelling method MERODE. Since then she has done further
research in the area of formal methods for object-oriented conceptual modelling. She now is Full Professor with the Management
Information Systems Group of the Faculty of Economics and Applied Economics at the Katholieke Universiteit Leuven in Belgium.
She has been involved in several industrial conceptual modelling projects. Her research interests are object oriented conceptual
modelling, software architecture and software quality.
Wilfried Lemahieu holds a Ph.D. from the Department of Applied Economic Sciences of the Katholieke Universiteit Leuven, Belgium (1999). At
present, he is associate professor at the Management Informatics research group of the Faculty of Economics and Applied Economics.
His teaching includes Database Management, Data Storage Architectures and Management Informatics. His research interests comprise
distributed object architectures and web services, object-relational and object-oriented database systems and hypermedia systems.
Jacques A. Vandenbulcke is professor at the Faculty of Economics and Applied Economics of the Katholieke Universiteit Leuven, Belgium. His main research
interests are in Database management, Data modelling, and Business Information Systems. He is co-ordinator of the Leuven Institute
for Research on Information Systems (LIRIS) and holder of the SAP-chair on ‘Extended enterprise infrastructures’. He is president
of ‘Studiecentrum voor Automatische Informatieverwerking (SAI)’, the largest society for computer professionals in Belgium,
and co-founder of the ‘Production and Inventory Control Society (PICS)’ in Belgium. 相似文献
This work describes the methanol, ethanol and formic acid oxidation using a metallic bilayer electrodeposited on a platinum substrate. Firstly, one monolayer of ruthenium was deposited on the substrate and over it a 1.1 layer of metallic platinum. In the blank solution it was observed that the electrochemical behavior of both the Pt/Ru/Pt and bulk Pt were very similar, except in the oxygen evolution potential region. Using X-ray photoelectronic spectroscopy (XPS) it was not possible to identify the presence of Ru atoms on the bilayer surface. The electroactive area and the RMS roughness factor measured with atomic force microscopy (AFM) for both materials are the same. A CO monolayer oxidation procedure confirmed that the systems have the same real surface area and also showed a shift in the negative direction for 54 mV on the CO peak potential for the bilayer. For the voltammetric organic molecules oxidation, an enhancement in the current densities of 350, 390 and 420% was observed for ethanol, methanol and formic acid, respectively, for the bilayer system compared to the bulk Pt electrodes. Also, a decrease of 110 mV in the beginning of the ethanol oxidation process was observed over the bilayer system compared to bulk Pt. 相似文献
Fifty-seven families with adolescent children participated in a study of a) the quality of family and friendship relationships in adolescence, and b) the quality of family, friendship, and romantic relationships of adolescents 7 years later. Observation measures and self-report questionnaires were used to examine the variables. Regression analyses showed that mothers' marital satisfaction, conjugal conflict, and quality of mother-daughter relationship in adolescence predicted daughters' satisfaction with romantic relationships in adulthood. However, only the parental variables during adolescence predicted the quality of friendship relationships in adulthood. This study highlighted the contribution that quality of family relationships in adolescence makes to the quality of interpersonal relationships in adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献