High-resolution electron field emission cathodes were fabricated at room temperature by a high throughput electrophoresis process using functionalized carbon nanotubes ͑CNTs͒. Well-defined and adherent CNT patterns with 20 m feature size were achieved on a variety of substrates with fine control of the CNT morphology. The cathodes show uniform emission pattern across the entire surfaces and emission current with long-term stability. This room-temperature liquid-phase process is efficient and has no intrinsic limit on the deposition area. The emission characteristics of these cathodes compare favorably to those from other fabrication methods for CNT based field emission display applications.
In this letter, we report a process for room-temperature assembly of patterned and periodic structures of carbon nanotubes ͑CNTs͒. Well-defined patterns with less than a 10-m linewidth and variable thickness were readily deposited. The CNTs show long-range in-plane orientation ordering and adhere strongly to the substrates. The self-assembled macroscopic structures emit electrons under applied electrical field with the emission characteristics comparable to those from the high-temperature or/and low-resolution deposition processes. This room-temperature self-assembly method can be utilized for assembly and integration of nanostructured materials for a variety of devices, including the field-emission displays.
Effective oscillator strength distributions are systematically generated and tabulated for the alkali atoms, the alkaline-earth atoms, the alkaline-earth ions, the rare gases and some miscellaneous atoms. These effective distributions are used to compute the dipole, quadrupole and octupole static polarizabilities, and are then applied to the calculation of the dynamic polarizabilities at imaginary frequencies. These polarizabilities can be used to determine the long-range C 6 , C 8 and C 10 atom-atom interactions for the dimers formed from any of these atoms and ions, and we present tables covering all of these combinations.
This paper focuses on an analysis of technical requirements for the design of a permanent magnet type electric variable transmission (PM-EVT), which is a novel series-parallel hybrid electric vehicle (HEV) powertrain concept. Similar to the planetary gear train used in the Toyota Prius II, the EVT also realizes the power split function. However, it is implemented in an electromagnetic way rather than in a mechanical way, as is the case for the Prius II with a planetary gear. In this paper, a procedure to define the technical requirements of an EVT is presented. Since the Toyota Prius II is a well-known series-parallel HEV, this vehicle is chosen as a reference. The engine, the battery and other necessary components are kept as input data. A dynamic simulation was performed in order to take into account different driving cycles. Then, based on an analysis of the simulation results (torque, speed and power) the technical requirements of the PM-EVT are defined. Finally, the PMEVT machine is designed. The PM-EVT design results are presented and validated using the finite element method. Author Keywords: Electric variable transmission , Permanent magnet machine , Planetary gear , Series-parallel HEV
Automotive engineers and researchers have proposed different Series-Parallel Hybrid Electric Vehicle SP-HEV topologies. The Toyota Hybrid System (THS) is the most known SP-HEV based vehicle, but alternative solutions such as Electric Variable Transmission (EVT) have been also proposed. Efficient comparison between these different solutions is a key point in order to estimate the added value of each topology. This paper presents the application of optimal control to two seriesparallel hybrid architectures for efficiency assessment purpose. The dynamic programming method is applied to the THS as well as to a virtual hybrid vehicle with an EVT. The way to take into account the supplementary degree of freedom provided by the decoupling of wheels and engine in both topologies is presented. The optimal fuel consumptions are then compared on different driving cycles and bring out an over consumption of the EVT topology. Then, a parametric study shows that inserting an appropriate gear ratio on the ICE shaft can improve the EVT efficiency that becomes close to the THS efficiency.
China is still faced with a challenge in cancer pain management. The purposes of this study are to assess the current status of cancer pain management, and physicians' attitudes in China towards cancer pain management. The survey was done in a Chinese general hospital; 427 physicians and 387 cancer pain patients participated. The survey consisted of questionnaires to evaluate cancer pain management and physicians' knowledge of, and attitudes towards, cancer pain management. A total of 43% of patients with cancer pain and 51% with bone pain felt that they had been inadequately treated. The physicians rated the main reason for not using opioid drugs as the strong and difficult to control side-effects. The four main barriers to optimal management of cancer pain were: inadequate pain assessment; excessive state regulation of the prescribing of opioids; inadequate staff knowledge of pain management; and lack of access to powerful analgesics. To conclude: In China, there are some special aspects of cancer pain management, including physicians' concern about using opioid drugs, fear of being unable to manage adverse effects of opioids, and inadequately treated bone pain.
To enhance the performance of hybrid electric vehicle and continuously variable transmission, and to achieve more varied operation modes, a novel breed of integrated electromechanical converter is presented, such as electrical variable transmission (EVT) and four-quadrant transducer. Synthesizing two electric machines, they are essentially electromagnetic theory-based converters with the function of speed, torque, and energy regulation. The feature of flexible and variable control makes them very suitable for use in automobiles, especially in hybrid electric vehicles, as a continuously variable transmission and integrated starter and generator. Furthermore, the operation of the internal combustion engine is optimized, and the reduction of fuel consumption and the improvement of vehicle performance are also achieved. Corresponding to different road loads and driver demands, several operating states and control strategies are possible. Based on a simplified structure, the mathematical model of the EVT has been built, and its power flow and control strategies under different operation modes, are also analyzed.Index Terms-Continuously variable transmission, control strategy, electric machine, hybrid electric vehicle, starter and generator.
Positronium (Ps) formation cross sections (n = 1, 2) in positron-hydrogen collisions in Debye plasma environment are calculated using the screening approximation model for various Debye screening lengths from the Ps formation thresholds to 50 eV. The effect of the screened Coulomb potential on Ps formation process is investigated by using the Debye-Hückel potential. The present results are compared with available theoretical calculations.
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