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排序方式: 共有318条查询结果,搜索用时 511 毫秒
1.
Meysam Akbari Omid Hashemipour Masoud Nazari Farshad Moradi 《International Journal of Circuit Theory and Applications》2019,47(7):1188-1198
This paper presents an energy-efficient switching scheme for successive approximation register (SAR) analogue-to-digital converter (ADC). The proposed scheme employs charge recycling method to keep the capacitor arrays free of transitional energy between bit generations except reset phase. In comparison with the conventional switching scheme, the proposed one achieves 100% transitional energy saving without considering reset phase. In addition, configuration of a 10-bit SAR ADC shows that the proposed switching scheme reduces the capacitor area by 25% compared with the conventional switching scheme. 相似文献
2.
EM Silini F Bosi NS Pellegata G Volpato A Romano S Nazari C Tinelli GN Ranzani E Solcia R Fiocca 《Canadian Metallurgical Quarterly》1994,424(4):367-373
Activation of K-ras gene by point mutations, a common finding in lung adenocarcinomas, has been suggested to decrease patient survival. We investigated 109 lung adenocarcinomas, mostly small, peripheral, stage I tumours (81/109) for presence of K-ras gene mutations at codons 12 and 13. Mutations were detected by denaturing gradient gel electrophoresis analysis of specific sequences amplified by polymerase chain reaction from DNA extracted from archival pathological material. Thirty-three of 109 (30.3%) tumours showed mutations at codon 12 (28/33, 84.8%) or 13 (5/33, 15.2%) of the gene. Mutations and type of nucleotide substitutions were differently distributed among cytological subtypes, being more prevalent among less differentiated (G2 and G3) tumours and among bronchial than bronchiolo-alveolar type adenocarcinomas. Survival analysis showed an adverse effect of K-ras mutation on survival, restricted to stage I tumours. Median survival for 81 stage I patients was 30 months for non-mutated tumours versus 20 months for mutated tumours (p = 0.016). Multivariate analysis showed that age of patient (p = 0.001) and K-ras mutation status (p = 0.04) were the only independent factors influencing survival significantly. These data strengthen the hypothesis that K-ras gene mutations may be useful in identifying a subgroup of patients with poor outcome. 相似文献
3.
Journal of Porous Materials - The present study aims to investigate the effects of iron (hydr)oxide phases formed during precipitation and the addition of different binders on the mechanical and... 相似文献
4.
Sanaz Nazari Hadi Basirzadeh 《International Journal of Control, Automation and Systems》2014,12(1):84-92
Therapeutic vaccines are being developed as a promising new approach to treatment for cancer patients. There are still many unanswered questions about which kind of therapeutic vaccines are the best for the cancer treatments? In this paper we consider a mathematical model, in the form of a system of ordinary differential equations (ODE), this system is an example from a class of mathematical models for immunotherapy of the tumor that were derived from a biologically validated model by Lisette G. de Pillis. The problem how to schedule a variable amount of which vaccines to achieve a maximum reduction in the primary cancer volume is consider as an optimal control problem and it is shown that optimal control is quadratic with 0 denoting a trajectory corresponding to no treatment and 1 a trajectory with treatment at maximum dose along that all therapeutics are being exhausted. The ODE system dynamics characterized by locating equilibrium points and stability properties are determined by using appropriate Lyapunov functions. Especially we attend a parametric sensitivity analysis, which indicates the dependency of the optimal solution with respect to disturbances in model parameters. 相似文献
5.
Sanaz Motamedi 《International journal of human-computer interaction》2013,29(6):427-439
By their nature, smartphones must have small screens, and that is one of their limitations. Many users have trouble reading information on the Internet on such small screens because Internet browsers are usually designed for computers that have larger screens than smartphones. This study evaluates the usability of alternative user interfaces when reading news articles on smartphones. An experiment was conducted involving 120 smartphone users who were asked to evaluate six types of user interfaces based on three methods (pop-up, full-screen, and auto-zooming) and two display orientations (horizontal, vertical) in one of two languages (English and Persian). The participants were assigned four typical tasks that users must perform to obtain information from the Internet, that is, finding, refinding, reading, and browsing; they were asked to conduct the tasks in random order. In addition, a questionnaire was used to measure the efficiency and effectiveness of the participants’ completion of the tasks, as well as their satisfaction, compatibility, and enjoyment of the undertakings. The results indicated that method, orientation, and language affected the actual usage and the time used. Based on the human factor experiment, the full-screen method was preferred in refinding and reading, whereas the pop-up method was preferred in browsing and finding. In terms of orientation, the vertical mode was preferred, and each user’s performance in the vertical mode was better in all tasks except browsing. Of interest, using the English language turned out to be more satisfying, enjoyable, and efficient to the Persian users who did the experiment in English as their second language. 相似文献
6.
In recent years, droughts with increasing severity and frequency have been experienced around the world due to climate change
effects. Water planning and management during droughts needs to deal with water demand variability, uncertainties in streamflow
prediction, conflicts over water resources allocation, and the absence of necessary emergency schemes in drought situations.
Reservoirs could play an important role in drought mitigation; therefore, development of an algorithm for operation of reservoirs
in drought periods could help to mitigate the drought impacts by reducing the expected water shortages. For this purpose,
the probable drought’s characteristics and their variations in response to factors such as climate change should be incorporated.
This study aims at developing a contingency planning scheme for operation of reservoirs in drought periods using hedging rules
with the objective of decreasing the maximum water deficit. The case study for evaluation of the performance of the proposed
algorithm is the Sattarkhan reservoir in the Aharchay watershed, located in the northwestern part of Iran. The trend evaluations
of the hydro-climatic variables show that the climate change has already affected streamflow in the region and has increased
water scarcity and drought severity. To incorporate the climate change study in reservoir planning; streamflow should be simulated
under climate change impacts. For this purpose, the climatic variables including temperature and precipitation in the future
under climate change impacts are simulated using downscaled GCM (General Circulation Model) outputs to derive scenarios for
possible future drought events. Then a hydrological model is developed to simulate the river streamflow, based on the downscaled
data. The results show that the proposed methodology leads to less water deficit and decreases the drought damages in the
study area. 相似文献
7.
Mojtaba Abbasian Mousa Pakzad Kobra Nazari 《Polymer-Plastics Technology and Engineering》2017,56(8):857-865
A bionanocomposite of grafted cellulose and organo-modified clay was synthesized through solution intercalation method. For this purpose, chloromethylstyrene was grafted onto cellulose using acryloylchloride and the subsequent free radical polymerization. The synthesized cellulose-graft-polychloromethylstyrene was used as an atom transfer radical polymerization macroinitiator of acrylonitrile in the presence of CuCl/2,2′-bipyridine catalyst system, to prepare the cellulose-graft-polychloromethylstyrene-graft-polyacrylonitrile terpolymer. For preparing the modified clay, Na-montmorillonite was mixed with hexadecyl trimethyl ammonium chloride salt. Finally, cellulose-graft-polychloromethylstyrene-graft-polyacrylonitrile/organoclay bionanocomposite was prepared in CCl4 by solution intercalation method. 相似文献
8.
9.
Ali Pourjavadi Mohammad Eskandari Seyed Hassan Hosseini Mojtaba Nazari 《国际聚合物材料杂志》2017,66(5):235-242
A noncovalent functionalization of the edges of reduced graphene oxide (RGO) with β-cyclodextrin-graft-hyperbranched polyglycerol (β-CD-g-HPG) was successfully performed via a host-guest interaction. The results showed that β-CD-g-HPG disperses the graphene sheets better than pure β-CD or HPG. The resulted supramolecular structure is stable in neutral water medium more than one week. However, in acidic medium the host-guest interaction is collapsed and graphene nanosheets precipitate. 相似文献
10.
Alper Kiziltas Behzad Nazari Douglas J. Gardner Douglas W. Bousfield 《Polymer Engineering and Science》2014,54(4):739-746
Melt rheology and crystallization behavior of polyamide 6 (PA 6) and microcrystalline cellulose (MCC) composites were systematically studied in this research. The incorporation of MCC into the PA 6 matrix resulted in higher complex viscosities (|η*|), storage modulus (G′), and shear viscosities than those of neat PA 6, especially at low frequencies. The orientation of rigid molecular chains in the composites introduced by the addition of MCC induced a strong shear thinning behavior with an increase in MCC loading. The non‐isothermal crystallization kinetics of PA 6 and MCC composites were investigated by differential scanning calorimetry. The Avrami and Tobin model were applied to describe the process of non‐isothermal crystallization and to determine the crystallization parameters of the composites. Analysis of the crystallization kinetics indicated that the Avrami (na) and Tobin exponent (nt) was altered by the MCC. It was also found that the Avrami and Tobin equations fit the empirical data well. POLYM. ENG. SCI., 54:739–746, 2014. © 2013 Society of Plastics Engineers 相似文献