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191.
1IntroductionIt is i mportant for the economic development of acountry to maintain the stabilization of exchange rate,so the intervention of exchange rate has become thetopic of the main concerns of the economic and math-ematical circles[1-5].To maintain the stabilization ofexchange rate,many countries use target zone re-gi mes,that is,the central banks intervene in the for-eign exchange market such that the exchange ratestays within the interval[a,b].There are fixed costand cost proportional … 相似文献
192.
To improve the aerodynamic performance of high-speed trains (HSTs) running in the open air, a multi-objective aerodynamic optimization design method for the head shape of a HST is proposed in this paper. A parametric model of the HST was established and seven design variables of the head shape were extracted. Sample points and their exact values of optimization objectives were obtained by an optimal Latin hypercube sampling (opt. LHS) plan and computational fluid dynamic (CFD) simulations, respectively. A Kriging surrogate model was constructed based on the sample points and their optimization objectives. Taking the total aerodynamic drag force and the aerodynamic lift force of the tail coach as the optimization objectives, the multi-objective aerodynamic optimization design was performed based on a non-dominated sorting genetic algorithm-II (NSGA-II) and the Kriging model. After optimization, a series of Pareto-optimal head shapes were obtained. An optimal head shape was selected from the Pareto-optimal head shapes, and the aerodynamic performance of the HST with the optimal head shape was compared with that of the original train in conditions with and without crosswinds. Compared with the original train, the total aerodynamic drag force is reduced by 2.61% and the lift force of the tail coach is reduced by 9.90% in conditions without crosswind. Moreover, the optimal train benefits from lower fluctuations in aerodynamic loads in crosswind conditions. 相似文献
193.
HUANG Biao YAN Guo-zheng LI Qian-ru 《浙江大学学报(A卷英文版)》2007,8(10):1560-1567
Antenna is very crucial to radiotelemetry capsules which can measure the physiological parameters of the gastroin- testinal (GI) tract. The objective of this paper is to design a novel spiral slots microstrip patch antenna for the radiotelemetry capsules communicating with external recorder at 915 MHz located in ISM (Industry, Science, and Medical) bands. The microstrip patch antenna is designed and evaluated using the finite-difference time-domain (FDTD) method. Return loss characteristics and the effect of the human body on resonant frequency are analyzed, and the performances of radiation patterns at different positions of the human alimentary tract are also estimated. Finally, specific absorption rate (SAR) computations are performed, and the peak 1-g and 10-g SAR values are calculated. According to the peak SAR values, the maximum delivered power for the designed antenna was found so that the SAR values of the antenna satisfy the ANSI (American National Standards Institute) limitations. 相似文献
194.
Objective: We aim to describe the environment iodine concentration in salt, water and soil along Zhejiang Province coast in the China foreland. It will be helpful for us to judge whether this area is insufficient in iodine and universal iodized salt is necessary or not. Methods: We collected iodized salt samples, drinking water samples (tap water in the towns, and well water or spring water in the villages), water samples from different sources (ditches, lakes, rivers) and soil samples through random sampling in June, 2005. Salt, water and soil iodine was detected by arsenic-cerium redox method. Statistical analysis was expressed as mean±SEMby Windows SPSS 13.0. Results: (1) The iodine concentration in salt was 27.9±4.33 mg/kg (n=108). (2) Seventy-five water samples were collected. The water iodine value was 0.6~84.8 μg/L (mean of 11.66 μg/L). The watershed along the Qiantang River has significantly higher iodine content than the water in Lin'an in mountain area (P<0.01). The iodine content and mean iodine content of tap water, well or spring water and natural water sources were 4.30±2.43 μg/L (n=34), 23.59±27.74 μg/L (n=19)and 12.72±10.72 μg/L (n=22) respectively. This indicated that among environmental water sources, the ditch iodine content was the highest with river water iodine being the lowest (P<0.01). (3) Soil iodine value was 0.11~2.93 mg/kg (mean of 1.32 mg/kg).Though there was no statistical difference of soil iodine in different districts (P=0.131), soil iodine content correlated positively with water iodine content. Conclusion: Iodine concentration in salt accords with national policy of adding iodine in salt. Foreland has more iodine in water than mountain area. The data reflected that water and soil iodine in foreland area was not high, which suggests universal iodized salt should be necessary. Environment iodine has relatively close association with pollution. 相似文献
195.
Melissa Tremblay Jacqueline Pei Denise Plesuk Aimee Muchortow Paula Mihai Rod Jordao 《International journal for the advancement of counseling》2017,39(1):82-97
There is a lack of systematic research on the training of clinicians toward providing counselling services and support to individuals with Fetal Alcohol Spectrum Disorder (FASD). The aim of this qualitative project was twofold: (1) to develop and pilot a clinical consultation process that would address clinicians’ reported need for greater communication and information sharing in serving clients affected by FASD; and (2) to build a model of FASD-informed clinical counselling practice by examining this consultation process and by capturing the experiences of clinicians who were involved. Findings from focus groups and meeting minutes are reported with respect to the model’s focus on reflection, communication, and action. 相似文献
196.
This study examined perceptions of college of education students and their experiences with Channel One, a privately-owned
news service used in public education. Given that about one-third of middle and high schoolers in the US view the broadcast
every school day, the authors surveyed 172 freshmen to discern their views and attitudes toward Channel One programming and
commercials and the role colleges and universities might play in relation to this media service. While most studies on Channel
One have been conducted from a K-12 point of view, the goal of this study was to reconsider the topic from the perspective
of prospective teachers and post-secondary education.
A. J. Angulo is Assistant Professor of Social Foundations, Winthrop University. He received an Ed.D. and Ed.M. from Harvard University.
His research interests include history of education, technology and education, and student rights.
Susan K. Green is Associate Professor of Educational Psychology, Winthrop University. She received a Ph.D. in social psychology from Loyola
University, Chicago and a Ph.D. in educational psychology and research from the University of South Carolina, Columbia. Her
interests include classroom assessment, motivational and instructional strategies to promote learning, and multicultural issues
in education. 相似文献
197.
This study investigated the effects of a brief meditation intervention on perceived stress, mindfulness, and sleep quality for college freshmen who have aged out of foster care. Thirty-six youth who had aged out of foster care and enrolled at a large midwestern 4-year university (n?=?16 experimental group, n?=?20 control group) participated in a study in which they were assessed three times on the dependent variables. Students also participated in a focus group after the intervention ended. Four sessions of the brief mindfulness intervention resulted in significant short-term reductions in stress levels and increases in sleep quality. Finding effective personal interventions to increase chances for college success for students with histories in foster care can also offer potential insight toward the development of educational models and resources for other vulnerable college student populations. 相似文献
198.
Tanfer Emin Tunc 《Children‘s Literature in Education》2017,48(3):245-261
This article discusses how, following in the footsteps of United States imperial children’s writers Jacob Abbott and Edward Stratemeyer, Mary Hazelton Blanchard Wade (1860–1936), the original author of the Our Little Cousins series (1901–1905), contributed to the American culture of empire. Wade was one of the most prolific and popular imperialistic turn-of-the-twentieth-century American children’s authors. Yet, she remains understudied and virtually unknown, except among a few scholars who have examined, briefly, a few of her most prominent texts. Given Wade’s current popularity within certain Christian Evangelical homeschooling circles, and the resurgence of imperialist and othering discourses as part of the War on Terror, revealing her project and understanding its messages and relevance for the twenty-first century, is today all the more urgent. 相似文献
199.
A precise micro-location compliant stage with elastics-supported system is enmployed for investigations.The general motion of stage supported by elastic structure is described.The analyses of forward displecement and inverse displacement of stage are formulated.The study of input-output behavior of compliant mechanisms actually belongs to a stress-strain field problem.By using finite element analysis.the compliance coefficients of the stage supported by ring are calculated.Finally,a case is inverstigated to exemplity these formulae. 相似文献
200.
Gwo-Jen Hwang Chiu-Lin Lai Jyh-Chong Liang Hui-Chun Chu Chin-Chung Tsai 《Educational technology research and development : ETR & D》2018,66(1):75-93
In this study, a one-year program was conducted to investigate the relationships between students’ perceptions of mobile learning and their tendencies of peer interaction and higher-order thinking in issue-based mobile learning activities. To achieve the research objective, a survey consisting of eight scales, namely, usability, continuity, adaptive content, collaboration, communication, problem-solving, critical thinking and creativity, was developed. A total of 658 students from 38 high schools in Taiwan filled in the questionnaire after experiencing issue-based mobile learning activities. From the exploratory and confirmatory factor analyses, it was found that the questionnaire had high reliability and validity. The structural equation model further revealed that the provision of adaptive content in the mobile learning had positive impacts on the students’ tendency to interact with peers (i.e., collaboration and communication), which further affected their tendency to engage in higher-order thinking (i.e., problem-solving, critical thinking, and creativity). The findings of this study provide a good reference for researchers and school teachers who intend to promote mobile learning in school settings. 相似文献