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排序方式: 共有44条查询结果,搜索用时 375 毫秒
1.
RA Bayoumi MS Nur-E-Kamal M Tadayyon KK Mohamed BH Mahboob MM Qureshi MS Lakhani MO Awaad J Kaeda TJ Vulliamy L Luzzatto 《Canadian Metallurgical Quarterly》1996,46(3):136-141
Operational skills involved in controlling a motor vehicle were measured in two groups of very healthy elderly drivers and a young control group to test the hypothesis that there are age-related declines in operational performance that may influence driver safety. An actual behind-the-wheel, standardized road test was employed using a motor vehicle equipped with sensors to record speed, braking activity, and lane position, as well as direction and magnitude of front-wheel and eye-movement excursions. The data from these sensors were used as dependent measures of operational performance. Older drivers made fewer steering and eye-movement excursions and drifted across the center line more frequently than the young control group. Younger drivers drove significantly faster and executed more braking applications than did their older counterparts. The motor-vehicle operational performance of older healthy drivers was related to visual-spatial attentional declines and the useful field of vision associated with the normal aging process. 相似文献
2.
我们已经建立了一种有效且通用的无催化剂的反应路线,用于获得二苯并[b,f][1,4]氧氮杂卓衍生物,所得产品的收率从较好到优秀(高达90%)。该过程涉及β-酮酸和环亚胺的无催化剂脱羧加成反应。 相似文献
3.
Sodeif Azadmard-Damirchi Mahboob Nemati Javad Hesari Masoud Ansarin Bahram Fathi-Achachlouei 《Journal of the American Oil Chemists' Society》2010,87(10):1155-1159
Phytosterols are separated into three classes: 4-desmethylsterols, 4-monomethylsterols and 4,4′-dimethylsterols. 4,4′-Dimethylsterols
are used to detect vegetable oil adulteration and some compounds from this class can have anti-inflammatory and anticancer
properties. There are methods such as thin layer chromatography (TLC) and solid phase extraction (SPE) used to separate phytosterol
classes from each other. However, in some cases, separation of all three classes is not required. In addition, TLC has some
drawbacks such as low recovery and it is time consuming. An SPE method has previously been used, but it was necessary to use
high volume of solvents with this method to avoid coelution of phytosterol classes. In this study, an SPE (silica, 1 g) method
was developed to separate and enrich only 4,4′-dimethylsterols from unsaponifiables of vegetable oil samples using 25 mL n-hexane and diethyl ether (95:5, v:v). This method was applied to hazelnut and olive oils and results were compared with those
of TLC and the previously developed SPE method. Recovery of 4,4′-dimethylsterols was two times higher with the new SPE method
compared with the TLC method. The newly developed SPE method generally gave a similar recovery compared with the previously
developed SPE method. Moreover, the SPE method developed in this study has the advantage of using a 3.5 times lower volume
of solvent than previously developed SPE methods. Because the newly developed SPE method has a single step requiring a low
volume of solvents, it is rapid and simple, and can easily be used to detect olive oil adulteration with hazelnut oil and
to analyze and quantify effective nutritional compounds in the 4,4′-dimethylsterols class. 相似文献
4.
Utilization of wind energy in Bangladesh has been slow mainly due to lack of quality wind data. Recent measurements in some places have shown significant wind energy potentials in Bangladesh. In this paper, a wind map is presented which incorporates several microscale features, such as terrain roughness, elevation etc. with a mesoscale model. Several meso-maps were obtained from global databases and a suitable model was chosen and modified for a 30-m elevation. Ground data from various sources were collected and modified for height and land condition adjustments based on local knowledge and GIS information. It was found that, the generated wind map and the modified ground data resemble. Annual average wind speed at 30 m height along the coastal belt is above 5 m/s. Wind speed in northeastern parts is above 4.5 m/s while inland wind speed is around 3.5 m/s for most part of Bangladesh. Small-scale wind turbines could be installed and tested in locations such as St. Martins Island, Cox’s Bazar, Patenga, Bhola, Barguna, Dinajpur, Thakurgaon and Panchagar. 相似文献
5.
Mahboob Mohammad 《Electrochimica acta》1977,22(4):487-488
Further electrochemical investigation and analysis of electrochemical data on 2,2′ and 4,4′-dinitrobibenzyl showed that these compounds reduce in two 1e steps with similar formal potentials. The disproportionation constants for 2,2′ and 4,4′-dinitrobibenzyl anion radicals as calculated from electrochemical data are 0.02 and 0.32 respectively. 相似文献
6.
Bougherara H Zdero R Mahboob Z Dubov A Shah S Schemitsch EH 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2010,224(10):1209-1219
This study proposes a novel hybrid total knee replacement (TKR) design to improve stress transfer to bone in the distal femur and, thereby, reduce stress shielding and consequent bone loss. Three-dimensional finite element (FE) models were developed for a standard and a hybrid TKR and validated experimentally. The Duracon knee system (Stryker Canada) was the standard TKR used for the FE models and for the experimental tests. The FE hybrid device was identical to the standard TKR, except that it had an interposing layer of carbon fibre-reinforced polyamide 12 lining the back of the metallic femoral component. A series of experimental surface strain measurements were then taken to validate the FE model of the standard TKR at 3000 N of axial compression and at 0 degreeof knee flexion. Comparison of surface strain values from FE analysis with experiments demonstrated good agreement, yielding a high Pearson correlation coefficient of R(2)= 0.94. Under a 3000N axial load and knee flexion angles simulating full stance (0O degree, heel strike (200 degrees, and toe off (600 degrees during normal walking gait, the FE model showed considerable changes in maximum Von Mises stress in the region most susceptible to stress shielding (i.e. the anterior region, just behind the flange of the femoral implant). Specifically, going from a standard to a hybrid TKR caused an increase in maximum stress of 87.4 per cent (O0 degree from 0.15 to 0.28 MPa), 68.3 per cent (200 degrees from 1.02 to 1.71 MPa), and 12.6 per cent (600 degrees from 2.96 to 3.33 MPa). This can potentially decrease stress shielding and subsequent bone loss and knee implant loosening. This is the first report to propose and biomechanically to assess a novel hybrid TKR design that uses a layer of carbon fibrereinforced polyamide 12 to reduce stress shielding. 相似文献
7.
8.
Swallow: Resource and Tag Recommender System Based on Heat Diffusion Algorithm in Social Annotation Systems 下载免费PDF全文
Vahideh Amel Mahboob Mehrdad Jalali Majid Vafaei Jahan Pegah Barekati 《Computational Intelligence》2017,33(1):99-118
Social annotation systems (SAS) allow users to annotate different online resources with keywords (tags). These systems help users in finding, organizing, and retrieving online resources to significantly provide collaborative semantic data to be potentially applied by recommender systems. Previous studies on SAS had been worked on tag recommendation. Recently, SAS‐based resource recommendation has received more attention by scholars. In the most of such systems, with respect to annotated tags, searched resources are recommended to user, and their recent behavior and click‐through is not taken into account. In the current study, to be able to design and implement a more precise recommender system, because of previous users' tagging data and users' current click‐through, it was attempted to work on the both resource (such as web pages, research papers, etc.) and tag recommendation problem. Moreover, by applying heat diffusion algorithm during the recommendation process, more diverse options would present to the user. After extracting data, such as users, tags, resources, and relations between them, the recommender system so called “Swallow” creates a graph‐based pattern from system log files. Eventually, following the active user path and observing heat conduction on the created pattern, user further goals are anticipated and recommended to him. Test results on SAS data set demonstrate that the proposed algorithm has improved the accuracy of former recommendation algorithms. 相似文献
9.
Schiavone Giuseppe Jones Thomas Price Dennis McPhillips Rachael Jiang Yun Qiu Zhen Meggs Carl Mahboob Syed O. Eljamel Sam Button Tim W. Demore Christine E. M. Cochran Sandy Desmulliez Marc P. Y. 《Microsystem Technologies》2017,23(9):3881-3891
Microsystem Technologies - State-of-the-art neurosurgery intervention relies heavily on information from tissue imaging taken at a pre-operative stage. However, the data retrieved prior to... 相似文献
10.
IP header compression schemes offer a valuable measure for bandwidth preservation. Such schemes have been practically implemented in infrastructure‐based IP networks for point‐to‐point links. However, minimal research and practical implementation efforts have been conducted in the direction of an IP header compression strategy that can meet the peculiar requirements of multi‐hop ad hoc wireless networks. In this paper, we present a practically implemented multi‐hop IP header compression scheme using the Robust Header Compression (ROHC) protocol suite. The scheme runs on a novel identifier (ID) based networking architecture, known as an ID‐based ad hoc network (IDHOCNET). IDHOCNET additionally solves a number of bottlenecks of pure IP‐based ad hoc networks that have emerged owing to IP address auto‐configuration service, distributed naming and name resolution, and the role of an IP address as an identifier at the application layer. The proposed scheme was tested on a multi‐hop test bed. The results show that the implemented scheme has better gain and requires only O (1) ROHC contexts. 相似文献