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排序方式: 共有106条查询结果,搜索用时 15 毫秒
1.
B Kirel S Yetgin U Saatci S Ozen A Bakkaloglu N Besbas 《Canadian Metallurgical Quarterly》1996,15(3):236-241
Brush border myosin-I (BBMI) is a single-headed unconventional myosin found in the microvilli of intestinal epithelial cells, where it links the core bundle of actin filaments to the plasma membrane. An association of BBMI with anionic phospholipids has been shown to be mediated by a carboxy-terminal domain which is rich in basic amino acids. We have exploited this natural affinity of BBMI for negatively charged lipids to form two-dimensional (2D) crystals of this protein which are suitable for structural analysis by electron crystallographic techniques. The 2D crystals which we have obtained belong to one of two space groups, p22121 or p2. We present here projection maps calculated from images of negatively stained crystals for each of these crystal types to a resolution of 20 A and show that the asymmetric unit is the same in both crystal types. 相似文献
2.
Acceptance, utility, and usability of system designs have become a focal interest in human–computer interaction (HCI) research, yet at present there is a lack detailed understandings of which system design features influence them. The purpose of the study is to examine the effects of five product design features; customization, adaptive behavior, memory load, content density, and speed on user preference through an experimental study by using conjoint analysis. In experimental study, instead of classical conjoint cards, prototypes were generated for products. Besides, desirability and market segments of product prototypes were identified. In line with the results, among the five product design features, speed is the most and customization is the least important features that affect user preference. Contrary to the expectations, customization has a relatively small importance value in this research. Subsequent design features that influence user preference after speed are minimal memory load, adaptive behavior, and content density, respectively. According to findings, interfaces that have high-speed, minimal memory load, adaptive behavior, low content density, and customization features are more preferable than those that do not. 相似文献
3.
4.
Maria Elizabeth Grabe Ozen Bas Irene Ingeborg van Driel 《The Journal of communication》2015,65(2):300-319
Education‐based knowledge gaps are well‐documented across countries, media platforms, and content. Without exception, knowledge is measured through words not images. Given the centrality of sight in the natural history of Homo sapiens, the extraordinary visual acuity of humans, and the proliferation of screen‐based visual media environments in contemporary life, an experiment was conducted to test the knowledge gap visually. Participants watched 8 audiovisual news stories. Simple recognition of story details and comprehension of that information were tested in verbal and visual modalities. Results offered the first confirmation of the knowledge gap in visual terms. Yet, gaps were significantly smaller employing visual than verbal measures, pointing to the need for continued efforts to develop visual measures for future memory studies. 相似文献
5.
Iranian Polymer Journal - Surface of Al2O3 nanoparticles was modified with a silane coupling agent, and aramid fiber-reinforced epoxy nanocomposites were produced using these particles. Three... 相似文献
6.
M. Grujicic G. Arakere B. Pandurangan V. Sellappan A. Vallejo M. Ozen 《Journal of Materials Engineering and Performance》2010,19(8):1116-1127
A multi-disciplinary design-optimization procedure has been introduced and used for the development of cost-effective glass-fiber
reinforced epoxy-matrix composite 5 MW horizontal-axis wind-turbine (HAWT) blades. The turbine-blade cost-effectiveness has
been defined using the cost of energy (CoE), i.e., a ratio of the three-blade HAWT rotor development/fabrication cost and
the associated annual energy production. To assess the annual energy production as a function of the blade design and operating
conditions, an aerodynamics-based computational analysis had to be employed. As far as the turbine blade cost is concerned,
it is assessed for a given aerodynamic design by separately computing the blade mass and the associated blade-mass/size-dependent
production cost. For each aerodynamic design analyzed, a structural finite element-based and a post-processing life-cycle
assessment analyses were employed in order to determine a minimal blade mass which ensures that the functional requirements
pertaining to the quasi-static strength of the blade, fatigue-controlled blade durability and blade stiffness are satisfied.
To determine the turbine-blade production cost (for the currently prevailing fabrication process, the wet lay-up) available
data regarding the industry manufacturing experience were combined with the attendant blade mass, surface area, and the duration
of the assumed production run. The work clearly revealed the challenges associated with simultaneously satisfying the strength,
durability and stiffness requirements while maintaining a high level of wind-energy capture efficiency and a lower production
cost. 相似文献
7.
In this paper, the performance of signaling strategies with high peak-to-average power ratio is analyzed in both coherent and noncoherent fading channels. Two modulation schemes, namely on-off phase-shift keying (OOPSK) and on-off frequency-shift keying (OOFSK), are considered. The optimal detector structures are identified and analytical expressions for the error probabilities are obtained for arbitrary constellation sizes. Numerical techniques are employed to compute the error rates. It is concluded that increasing the peakedness of the signals results in reduced error rates for a given power level and hence equivalently improves the energy efficiency for fixed error probabilities. 相似文献
8.
CY Bilen K Mahalati A Sahin I Tekin H Ozen D Remzi 《Canadian Metallurgical Quarterly》1997,29(3):301-306
1. This study was to determine the effects of heat load early in life on thermoregulatory responses and whole blood viscosity of broilers during a subsequent exposure to high environmental temperature later in life. 2. The birds, which had been subjected to exposure to 38 degrees C for 24 h at 5-d-old, served as prior exposure group (group A). Both group A and control group B were exposed to 33 degrees C for 3 h when near marketable weight. 3. On exposure to 33 degrees C, although there were no significant differences in the increases in heat production (HP) between the two groups, abdominal temperature (Ta), temperature of external ear tract (Tee), shank skin temperature (Tss), standing-lying frequency and lying time were lower in group A than in group B. Heart rate (HR) and comb surface temperature (Tcs) did not differ but increased in both groups during exposure to 33 degrees C. Respiration rate (RR) was greater in group A. 4. Blood viscosity decreased markedly in both groups after exposure to 33 degrees C; the decrease was greater in group A. 5. These results suggest that early exposure may promote broilers' ability to cope with the subsequent heat load by altering thermoregulatory physiological responses and behavioural patterns, resulting in an alleviation of heat stress. 相似文献
9.
An 8-year-old male, who had Down syndrome associated with systemic lupus erythematosus (SLE), is described. He also had a partial complement 4 deficiency. This case is a reminder that the physician should be aware of the possibility of an immune defect in a male presenting with SLE at a young age. The question of whether the association of Down syndrome with SLE is coincidental or whether there is a predilection for autoimmune disorders in Down syndrome is discussed. 相似文献
10.
Gursoy M.C. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2009,55(10):4543-4567
In this paper, the capacity and energy efficiency of training-based communication schemes employed for transmission over a priori unknown Rayleigh block-fading channels are studied. Initially, the case in which the product of the estimate error and transmitted signal is assumed to be Gaussian noise is considered. In this case, it is shown that bit energy requirements grow without bound as the signal-to-noise ratio (SNR) goes to zero, and the minimum bit energy is achieved at a nonzero SNR value below which one should not operate. The effect of the block length on both the minimum bit energy and the SNR value at which the minimum is achieved is investigated. Flash training and transmission schemes are analyzed and shown to improve the energy efficiency in the low-SNR regime. In the second part of this paper, the capacity and energy efficiency of training-based schemes are investigated when the channel input vector in each coherence block is subject to peak power constraints. The capacity-achieving input structure is characterized and the magnitude distribution of the optimal input is shown to be discrete with a finite number of mass points. The capacity, bit energy requirements, and optimal resource allocation strategies are obtained through numerical analysis. The improvements in energy efficiency when on-off keying (OOK) with fixed peak power and vanishing duty cycle is employed are studied. 相似文献