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81.
The design of phosphorus-containing cavity architectures that are of interest for biomimetics and other interdisciplinary sciences is among the most high-priority lines of research in modern organophosphorus chemistry. This Account acquaints the readers with methods for the design of rigid phosphomacrocyclic systems based on resorcinarenes, which differ in the nature of the phosphorus functions on the upper rim of the molecular bowl and have fixed dimensions of the molecular cavity. The authors demonstrate the possibility of attaining stereoselectivity in the synthesis of phospho(III)cavitands and their various transformations. 相似文献
82.
Abrahamson David; Schludermann Shirin; Schludermann Eduard 《Canadian Metallurgical Quarterly》1973,41(2):320
Employed 120 male and 113 female undergraduates in a replication of H. L. Mirels's (see record 1970-10386-001) study which found 2 factors in analyzing responses to 23 items on Rotter's Internal-External Control Scale. The same polar dimensions of "luck" as the arbiter of life events as opposed to personal control were found as well as a 2nd dimension of degree of control over political and social institutions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
83.
Herminio Martínez Eva Vidal Eduard Alarcón Alberto Poveda 《Analog Integrated Circuits and Signal Processing》2009,61(3):231-246
Continuous-time filters with automatic tuning loops are nonlinear feedback systems that are potentially unstable. To ensure
stability, particularly if the design of the loop controllers is to be improved, the appropriate linear dynamic modeling of
the tunable filter, including control inputs, should be attained. This work aims to present a general dynamic modeling of
continuous-time analog filters with automatic tuning capability. The general analysis leads to an equivalent small-signal
linearized incremental model, from which transfer functions between output variables and control voltages are obtained. Subsequent
to the analysis, it is possible to design compensated loops with enhanced stability and dynamic performance. By way of example,
the modeling of a particular band-pass CMOS continuous-time analog filter is presented in this paper. Two transfer functions
are derived: the transfer function between the output phase shift and the central frequency control voltage, and that between
the output amplitude and the quality factor control voltage. These functions are required to properly tune the central frequency
and quality factor parameters. This modeling makes it possible to propose an adaptive controller with improved stability and
a possible implementation for such a controller. Finally, experimental results are shown for a CMOS 0.8 μm technology. 相似文献
84.
Eduard Grasa Sergi Figuerola Albert Forns Gabriel Junyent 《Optical Switching and Networking》2009,6(2):120-128
Data-intensive high performance, high quality digital media traffic cannot be accommodated on traditional Layer 3 networks. Alternative technologies to transmit this traffic through the network, such as optical multicast, are being investigated. A prototype of an optical multicast service was showcased during the 7th Annual LambdaGrid Workshop celebrated in Prague last September. The prototype used Time Division Multiplexing (TDM) technology as the data plane and Argia (the evolution of UCLP) as the control/service plane. This paper describes the extensions that were done to the Argia Software to provide the Dynamic Optical Multicast Service and shows the results achieved during the Prague demonstration. 相似文献
85.
Eduard Caicedo-Casso Jessica Sargent Rachel M. Dorin Ulrich B. Wiesner William A. Phillip Bryan W. Boudouris Kendra A. Erk 《应用聚合物科学杂志》2019,136(6):47038
Rotational and oscillatory shear rheometry were used to quantify the flow behavior under minimal and significant solvent evaporation conditions for polymer solutions used to fabricate isoporous asymmetric membranes by the self-assembly and non-solvent induced phase separation (SNIPS) method. Three different A-B-C triblock terpolymer chemistries of similar molar mass were evaluated: polyisoprene-b-polystyrene-b-poly(4-vinylpyridine) (ISV); polyisoprene-b-polystyrene-b-poly(N,N-dimethylacrylamide) (ISD); and polyisoprene-b-polystyrene-b-poly(tert-butyl methacrylate) (ISB). Solvent evaporation resulted in the formation of a viscoelastic film typical of asymmetric membranes. Solution viscosity and film viscoelasticity were strongly dependent on the chemical structure of the triblock terpolymer molecules. A hierarchical magnitude (ISV > ISB > ISD) was observed for both properties, with ISV solutions displaying the greatest solution viscosity, fastest film strength development, and greatest strength magnitude. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47038. 相似文献
86.
87.
Amini M Abbaspour KC Berg M Winkel L Hug SJ Hoehn E Yang H Johnson CA 《Environmental science & technology》2008,42(10):3669-3675
Contamination of groundwaters with geogenic arsenic poses a major health risk to millions of people. Although the main geochemical mechanisms of arsenic mobilization are well understood, the worldwide scale of affected regions is still unknown. In this study we used a large database of measured arsenic concentration in groundwaters (around 20,000 data points) from around the world as well as digital maps of physical characteristics such as soil, geology, climate, and elevation to model probability maps of global arsenic contamination. A novel rule-based statistical procedure was used to combine the physical data and expert knowledge to delineate two process regions for arsenic mobilization: "reducing" and "high-pH/ oxidizing". Arsenic concentrations were modeled in each region using regression analysis and adaptive neuro-fuzzy inferencing followed by Latin hypercube sampling for uncertainty propagation to produce probability maps. The derived global arsenic models could benefit from more accurate geologic information and aquifer chemical/physical information. Using some proxy surface information, however, the models explained 77% of arsenic variation in reducing regions and 68% of arsenic variation in high-pH/oxidizing regions. The probability maps based on the above models correspond well with the known contaminated regions around the world and delineate new untested areas that have a high probability of arsenic contamination. Notable among these regions are South East and North West of China in Asia, Central Australia, New Zealand, Northern Afghanistan, and Northern Mali and Zambia in Africa. 相似文献
88.
Shafirah Samsuri Ngiam Li Jian Farah Wahida Jusoh Eduard Hernández Yáñez Noor Yahida Yahya 《化学工程与技术》2020,43(3):447-456
The application of solvent-aided crystallization (SAC) is based on the addition of a solvent, here 1-butanol, to crude biodiesel to catalyze the purification process by separating biodiesel from contaminants via crystallization process. Response surface methodology was applied to optimize the process parameters of SAC, represented by biodiesel purity. The purified biodiesel was analyzed by means of gas chromatography-mass spectrometry for the composition of the present fatty acid methyl ester (FAME). Under the predicted optimum process conditions within the experimental ranges for the highest biodiesel purity, the predicted biodiesel purity was 99.375 %. 相似文献
89.
90.
Valentina Shkodich Nadezhda Temnikova Irina Boyko Heinrich Leicht Eduard Kraus Natalia Shkodich Oleg Stoyanov 《应用聚合物科学杂志》2020,137(16):48582
Using the methods of infrared spectroscopy (IRS) and X-ray photoelectron spectroscopy (XPS), it was shown that short-term high-energy machining of detonation nanodiamonds (DND) leads to structural changes in the crystal structure and functional composition of the surface layer on particles. The possibility of spontaneous formation for stable colloidal systems with a narrow size distribution of mechanically activated DND in phenol-formaldehyde oligomers (PFO) was established. By molecular spectroscopy it was revealed that π → π* interactions of the aromatic rings of PFO are caused by orientational phenomena as a result of hydrogen bonds between an activated DND surface and functional groups of PFO. The effect of DND concentration on the curing reaction parameters ofpsgr the phenol-formaldehyde oligomer was determined by differential scanning calorimetry (DSC). The concentration effect of mechanically activated nanodiamonds on the physical and mechanical characteristics of a composite material based on phenol-formaldehyde binder and polyamide paper (Nomex) was studied. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48582. 相似文献