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This paper reports the improvement of rectification effects in diffuser∕nozzle structures with viscoelastic fluids. Since rectification in a diffuser∕nozzle structure with Newtonian fluids is caused by inertial effects, micropumps based on this concept require a relatively high Reynolds numbers and high pumping frequencies. In applications with relatively low Reynolds numbers, anisotropic behavior can be achieved with viscoelastic effects. In our investigations, a solution of dilute polyethylene oxide was used as the viscoelastic fluid. A microfluidic device was fabricated in silicon using deep reactive ion etching. The microfluidic device consists of access ports for pressure measurement, and a series of ten diffuser∕nozzle structures. Measurements were carried out for diffuser∕nozzle structures with opening angles ranging from 15° to 60°. Flow visualization, pressure drop and diodicity of de-ionized water and the viscoelastic fluid were compared and discussed. The improvement of diodicity promises a simple pumping concept at low Reynolds numbers for lab-on-a-chip applications.  相似文献   
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Tertiary Education and Management - The following article is being retracted from publication in Tertiary Education and Management: ‘Management and academic practices to prevent higher...  相似文献   
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This paper is concerned with the participation of students from low socio-economic status (SES) families and communities in Australian higher education. One means of achieving this, as purported by the Australian Government and various universities, is through the raising of family aspirations or expectations. In this paper, I explore the localised effects of raised family aspirations as they are understood within the lived experiences of some students from a low SES context. Based on the interactions in four focus groups of eight participants and five follow-up individual interviews run in a low SES school in Western Sydney, I draw broadly on the method advanced by Giorgi [1985. Phenomenology and psychological research. Pittsburgh, PA: Duquesne University Press] to attend to how certain forms of high expectations communicated by parents may have a deleterious effect on student aspiration and attainment insofar as it positions the latter in a ‘double bind’. Such a situation can be inferred to significantly reduce the incentives for higher education participation.  相似文献   
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Spatially varied surface treatment of a fluorescently labeled Bovine Serum Albumin (BSA) protein, on the walls of a closed (sealed) microchannel is achieved via a well-defined gradient in plasma intensity. The microchips comprised a microchannel positioned in-between two microelectrodes (embedded in the chip) with a variable electrode separation along the length of the channel. The channel and electrodes were 50 μm and 100 μm wide, respectively, 50 μm deep, and adjacent to the channel for a length of 18 mm. The electrode separation distance was varied linearly from 50 μm at one end of the channel to a maximum distance of 150, 300, 500, or 1000 μm to generate a gradient in helium plasma intensity. Plasma ignition was achieved at a helium flow rate of 2.5 ml/min, 8.5 kVpk-pk, and 10 kHz. It is shown that the plasma intensity decreases with increasing electrode separation and is directly related to the residual amount of BSA left after the treatment. The plasma intensity and surface protein gradient, for the different electrode gradients studied, collapse onto master curves when plotted against electrode separation. This precise spatial control is expected to enable the surface protein gradient to be tuned for a range of applications, including high-throughput screening and cell-biomolecule-biomaterial interactions.  相似文献   
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This investigation assessed whether prior heavy resistance exercise would improve the repeated sprint performance of 16 trained youth soccer players (Age 17.05 ± 0.65 years; height 182.6 ± 8.9 cm; body mass 77.8 ± 8.2 kg). In session 1, individual 1 repetition max was measured utilising a squat movement. In sessions 2 and 3, participants performed a running-based repeated anaerobic sprint test with and without prior heavy resistance exercise of 91% of their 1 repetition max. Times were recorded for each of the 6 sprints performed in the repeated sprint test and summed to provide total time. T-tests compared the two exercise conditions via differences in corresponding sprint times and total time. Analysis revealed significantly reduced total time with use of heavy resistance exercise (33.48 (±1.27) vs. 33.59 (±1.27); P = 0.01). Sprints 1 (P = 0.05) and 2 (P = 0.02) were also faster in the heavy resistance exercise condition (5.09 (±0.16) vs. 5.11 (±0.16) and 5.36 (±0.24) vs. 5.45 (±0.26) seconds respectively) although no other differences were shown. Findings demonstrate improved sprint times of trained adolescent soccer players after heavy resistance exercise although benefits appear not as sustained as in adult participants.  相似文献   
38.
From 1986 to 1988, Regional Centre for Education in Science and Mathematics (RECSAM) at Penang organised the Computers in Education Project with financial support from the Australian Government. The aim of the Project was to provide information on the use of computers in education among SEAMEO countries. Such information, it was thought, could be useful for educators who needed to formulate sound policies regarding the introduction, management, and use of computers in schools and the roles of computers in education in general. Six countries took part in this project including a team from Singapore.  相似文献   
39.
The research function of universities in Japan   总被引:1,自引:0,他引:1  
Japan has long led the trend towards privatization of Research andDevelopment (R&D). With the recent establishment of corporate R&Dfacilities overseas, this has become more international in character. Therelative impoverishment of Japanese academic science has only recently begunto be addressed by the government. Despite the neglect, there appears to bea gradual increase in Japanese academic research, but international researchcollaborations are still quite limited in number. There are growing tieswith industry, but industry has been slow to recognize the value of graduateschool training. Stronger links may promote greater research activity, butwithout reforms to the structure of the education system and Ministry ofEducation policies, Japan will not be prepared to meet the challenge of the21st century, and the need for a highly-skilled, innovative workforce.  相似文献   
40.
Maturation of Human Fetal Responses to Vibroacoustic Stimulation   总被引:3,自引:0,他引:3  
Maturation of human fetal response to vibroacoustic stimulation was examined in 60 fetuses from 23 to 36 weeks gestational age. Subjects received vibroacoustic or no-stimulus control trials (randomly assigned) while fetal heart rate (FHR) was recorded and movement was observed on real-time ultrasound scan. Initially, at 26-28 weeks, a small FHR deceleration response occurred; subsequently, FHR acceleration responses occurred. From 29 weeks, 83%-100% of subjects responded with an FHR acceleration > or = 10 BPM on the first vibrator trial and accelerations were observed on 83%-92% of all vibrator trials. From 26 to 36 weeks the percentage of fetuses responding with movement on the first vibrator trial increased from 58% to 100%; on all vibrator trials responses increased from 53% to 94%. It was concluded that maturation of human fetal response to vibroacoustic stimulation begins at about 26 weeks gestation, increases steadily over a 6-week period, and reaches maturity at about 32 weeks.  相似文献   
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