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32.
Electrorotation is widely used for characterization of biological cells and materials using a rotating electric field. Generally, multiphase AC electric fields and quadrupolar electrode configuration are needed to create a rotating electric field for electrorotation. In this study, we demonstrate a simple method to rotate dielectrophoretically trapped microparticles using a stationary AC electric field. Coplanar interdigitated electrodes are used to create a linearly polarized nonuniform AC electric field. This nonuniform electric field is employed for dielectrophoretic trapping of microparticles as well as for generating electroosmotic flow in the vicinity of the electrodes resulting in rotation of microparticles in a microfluidic device. The rotation of barium titanate microparticles is observed in 2-propanol and methanol solvent at a frequency below 1 kHz. A particle rotation rate as high as 240 revolutions per minute is observed. It is demonstrated that precise manipulation (both rotation rate and equilibrium position) of the particles is possible by controlling the frequency of the applied electric field. At low frequency range, the equilibrium positions of the microparticles are observed between the electrode edge and electrode center. This method of particle manipulation is different from electrorotation as it uses induced AC electroosmosis instead of electric torque as in the case of electrorotation. Moreover, it has been shown that a microparticle can be rotated along its own axis without any translational motion. 相似文献
33.
Amin L Ahmad J Jahi JM Nor AR Osman M Mahadi NM 《Public understanding of science (Bristol, England)》2011,20(5):674-689
Despite considerable research in advanced countries on public perceptions of and attitudes to modern biotechnology, limited effort has been geared towards developing a structural model of public attitudes to modern biotechnology. The purpose of this paper is to identify the relevant factors influencing public attitudes towards genetically modified (GM) soybean, and to analyze the relationship between all the attitudinal factors. A survey was carried out on 1,017 respondents from various stakeholder groups in the Klang Valley region. Results of the survey have confirmed that attitudes towards complex issues such as biotechnology should be seen as a multifaceted process. The most important factors predicting support for GM soybean are the specific application-linked perceptions about the benefits, acceptance of risk and moral concern while risk and familiarity are significant predictors of benefit and risk acceptance. Attitudes towards GM soybean are also predicted by several general classes of attitude. 相似文献
34.
Norzaini Azman Ibrahim Che Omar Aida Suraya Md Yunus Ahmad Nurulazam Md Zain 《牛津教育评论》2016,42(1):71-88
The expansion and transformation of Malaysian universities have generated major changes in the nature of academic employment and the structure of academic promotion in higher education institutions. These changes have considerable implications, in particular for the policy and practice of academic promotion in the public universities. We argue that despite sharing one common grade and salary system, distinct and significant differences exist in the academic promotion systems of the public universities. Drawing on one recent study on the academic promotion process in Malaysian public universities to contextualise our discussion, this paper highlights the complexity in the promotion process in these institutions. It also discusses and articulates the attendant issues and challenging aspects of the academic promotion process. We argue that the interrelated issues and challenges, and certain academic practices and habits stemming from the pressure to gain a promotion are pervasive, and that they affect the academic value system and work culture. We conclude by asserting the importance of applying a consistent standard for promotion within a single salary system and that the academic promotion system in the public universities should ultimately affirm and communicate core academic values, and also aim at obtaining evidence of excellent accomplishments. 相似文献
35.
K. Husain R. N. Sahu R. Rahman A. Nair 《Indian journal of clinical biochemistry : IJCB》1995,10(1):45-47
The levels of norepinephrine (NE), dopamine (DA) serotonin (5-HT) and its metabolite 5-hydroxyindole acetic acid (5-HIAA)
have been determined in the cerebrospinal fluid (CSF) of normal (n=25) and suicidal attempt cases (n=30). A significant decrease
in the level of NE (p<0.01), 5-HT(p<0.001) and 5-HIAA (p<0.001) in the CSF of suicide attempt cases were observed as compared
to normal controls. It is concluded that CSF 5-HIAA level which is drastically depleted may be used as an early biochemical
indicator of suicidal attempt so that it may be treated by the drugs which can enhance the suppressed neurotransmitter activity. 相似文献
36.
Md. Shajedur Rahman 《Teacher Development》2019,23(1):121-138
This paper is aimed at exploring teachers’ perceptions and practices of peer support in Bangladeshi primary schools. It also looks into the contrast between the perceptions and practices, and the underlying reasons behind such deviations. The study collects data from teachers who are undergoing a large-scale teacher development project called English in Action. The project provides face-to-face and distance learning support to the teachers, as well as promotes the idea of context-based learning through peer support in both primary and secondary schools in Bangladesh. This study adopted a mixed method approach. The quantitative part looks into teachers’ perceptions and practices in regards to peer support. A close-ended questionnaire was used to understand the extent teachers feel peer support is important and their actual engagement with colleagues for the support activities. Qualitative methods including observations, focus group discussions, and interviews are used to identify the activities that teachers do together with their colleagues in a school and the barriers to such activities. The results show that, teachers define peer support in a specific way and consider it as very important for their professional development. However, their engagement in such activities is restricted by several factors. 相似文献
37.
Smiddy Nieuwenhuis Tieme W. P. Janssen Denise J. van der Mee Farah A. Rahman Martijn Meeter Nienke M. van Atteveldt 《Mind, Brain, and Education》2023,17(2):123-131
Growth mindset, the belief that personal attributes such as intelligence are malleable, has previously been related to more effort investment. Here, we investigated how undergraduates' mindset (N = 114) relates to the choice to invest effort during an arithmetic task, indexed by whether they make low vs. high effort-related choices. Social cognitive theory suggests that past performance experiences (mastery vs. failure) and physiological state are important sources for competence self-evaluations. Therefore, in addition to mindset, we also investigated how effort-related choices are influenced more dynamically, by failures and physiological responses during the task. Growth mindset and physiological effort mobilization did not predict effort-related choices but making mistakes did predict lower effort choices in the subsequent round. This study further supports the importance of mastery experiences for effort investment and provides a novel approach for integrating different levels of influence on effort-related choices during an educationally-relevant task. 相似文献
38.
RAHMAN M.M ARIFFIN A.K. JAMALUDIN N HARON C.H.C. 《浙江大学学报(A卷英文版)》2006,7(11):1819-1830
INTRODUCTION Fatigue durability has long been important issues in the design of a two-stroke free piston linear engine structure (Torres and Voorwald, 2002; Rahman et al., 2005a; 2005b). Durability assessment is traditionally done in the later part of the product development stage when prototypes are available, and heavily re- lied on in confirming ground durability tests. This process is very time consuming and often results in over-design with weight penalties, which is the major obsta… 相似文献
39.
M. Shamsul Alam M. Abul Kalam Azad Kamalesh Chandra Roy M. Majedur Rahman 《Journal of The Franklin Institute》2009,346(2):112-125
This paper attempts to show the more suitability of the extended general Struble's technique than the unified Krylov-Bogoliubov-Mitropolskii (KBM) method in solving the problems that occur during the critical conditions. Recently a critically damped condition of an nth, n=2,3, … order weakly nonlinear autonomous ordinary differential equation has been investigated by the unified KBM method, in which the corresponding unperturbed equation has some real (negative) repeated eigenvalues. But there are more important critical conditions, which are still untouched. One of them occurs when a pair of complex eigenvalues is equal to another. It is complicated to formulate as well as to utilize the KBM method to investigate this condition. However, the extended general Struble's technique is applicable to both autonomous and non-autonomous systems. Solutions obtained for different critical conditions as well as for different initial conditions show a good agreement with the numerical solutions. The method is illustrated by an example of a fourth-order nonlinear differential equation whose unperturbed equation has repeated complex eigenvalues. A steady-state solution is determined for the non-autonomous equation. Moreover, a critical condition of a fourth-order nonlinear equation is investigated when two real eigenvalues of the unperturbed equation are non-positive and equal. 相似文献
40.
Ashik Ahmed Md. Mehedi Hassan Galib Shafi Md. Kawsar Zaman Golam Sarowar 《Journal of The Franklin Institute》2018,355(1):197-217
In wind power system, low frequency oscillations are observed due to imbalance between mechanical input and electrical output. Hence, variable susceptance controllers are being adopted to mitigate these oscillations. However, improper modulation of control parameters also leads to system instability. Therefore, we propose an optimization methodology for mitigating low frequency oscillations in wind power generation system. To visualize our methodology, we use a lead-lag type variable susceptance controller for fixed speed induction generator (FSIG) based wind generation system. Then, we optimize gain and time constants of lead-lag controller using three optimization algorithms: particle swarm optimization (PSO), genetic algorithm (GA), and flower pollination algorithm (FPA). Later, we perform non-linear time domain simulation and quantitative analysis to find average fitness, standard deviation, run time, and iteration number for these optimization algorithms. Moreover, non-parametric statistical analysis, such as Kolmogorov–Smirnov and Wilcoxon signed-rank tests are employed for identifying statistically significant differences among these algorithms. 相似文献