[en] Highlights: • The energy flow of an electric vehicle with regenerative brake is analyzed. • Methodology for measuring the regen brake contribution is discussed. • Evaluation parameters of regen brake contribution are proposed. • Vehicle tests are carried out on chassis dynamometer. • Test results verify the evaluation method and parameters proposed. - Abstract: This article discusses the mechanism and evaluation methods of contribution brought by regenerative braking to electric vehicle’s energy efficiency improvement. The energy flow of an electric vehicle considering the braking energy regeneration was analyzed. Then, methodologies for measuring the contribution made by regenerative brake to vehicle energy efficiency improvement were introduced. Based on the energy flow analyzed, two different evaluation parameters were proposed. Vehicle tests were carried out on chassis dynamometer under typical driving cycles with three different control strategies. The experimental results the difference between the proposed two evaluation parameters, and demonstrated the feasibility and effectiveness of the evaluation methodologies proposed

[en] Heteroatom-doped carbon with 4.06% of nitrogen and 10.42% of oxygen was synthesized by pyrolysis of ortho-aminophenol/formaldehyde resin. After high temperature hydrogen reduction, 2.22% of the surface oxygen was removed while the nitrogen content remained almost no change. The specific surface area enlarged from 90 m"2 g"−"1 to 226 m"2 g"−"1 and abundant micropores appeared. But we found that the specific capacitance of the reduced carbon as electrode for supercapacitors was decreased nearly 25 %. By measuring the conductivity, surface wettability, and electrochemical impedance, we proposed that (a) surface oxygen played an important role in the capacitive performance, especially the pseudocapacitance; (b) though the doped-oxygen reduced the electronic conductivity, on the other hand, enhanced the surface wettability and ion diffusion rate of the carbon electrodes.

[en] Highlights: • A braking energy regeneration system has been designed for a fuel cell bus. • Control strategy coordinating energy efficiency and brake safety is proposed. • The system and control strategy proposed are experimentally verified. • Based on test results, energy efficiency of the FCB is improved greatly. - Abstract: This paper presents the braking energy regeneration control of a fuel cell hybrid electric bus. The configuration of the regenerative braking system based on a pneumatic braking system was proposed. To recapture the braking energy and improve the fuel economy, a control strategy coordinating the regenerative brake and the pneumatic brake was designed and applied in the FCHB. Brake safety was also guaranteed by the control strategy when the bus encounters critical driving situations. Fuel economy tests were carried out under China city bus typical driving cycle. And hardware-in-the-loop tests of the brake safety of the FCHB under proposed control strategy were also accomplished. Test results indicate that the present approach provides an improvement in fuel economy of the fuel cell hybrid electric bus and guarantees the brake safety in the meantime

[en] Studies of the emission from rapid reaction of n-hexane and oxygen mixtures show that it mainly extends from 400 nm to the upper measured spectral limit of 830 nm. The spectra in this study consist of line, bands and the continuum emission. Bands of some intermediates produced in the reaction such as C₂, CH, CH₂O, CHO, OH, H₂O and CO₂ are identified under high-resolution spectroscopic measurements. According to the variations in radiation intensities with time of some important radicals or products, the authors discuss the effects of Al powder on the rapid reaction. Finally, the ignition mechanisms of n-hexane is speculated

[en] Thomson scattering is a powerful diagnostic of laser-produced plasmas because it can provide simultaneously a measurement of the electron density, electron and ion temperatures, plasma expansion velocity, degree of ionization and heat flow with relatively high resolving power. The authors introduce the basic theory of Thomson scattering and its important applications in new diagnostic fields such as high Z plasmas, two-species plasmas, gas-jet plasmas and high density plasma. Current developments of Thomson scattering research in China is also briefly reviewed

[en] The self-generated magnetic field, the angular and energy distributions of hot electrons produced in the interactions of ultra-short laser pulse with plasmas are studied in various experimental parameters. The spatial and temporal evolution of femtosecond laser plasmas are diagnosed by using optical probe beam. The average value of the magnetic field was estimated to be as high as 1.0 +- 0.3 MG in underdense plasma region. It is believed that this axial magnetic field is related with the dynamo effect in laser-plasma interaction. The hot electrons escaped from plasma show very high directionality, and their energy distribution have two Maxwellian components

[en] The interaction process of femtosecond laser pulses with metal photocathodes is studied. Based on the ultrashort electron pulses generated by this process we propose a conceptual design of time resolved electron microscopy. Its feasibility is analyzed, and the problem of control and propagation of the electron pulses discussed. (author)

[en] High speed plasma jets are generated by ablating half-cylinder-shell targets with two laser bunches on Shenguang Ⅱ Laser Facility. Using optical and X-ray diagnostics, the parameters of the plasma jets have been measured. Propagating in vacuum, the jets are collimated. One-dimensional hydrodynamic simulation is used to indirectly calculate the jet velocity. The collimation of the jets may be attributed to the expansion cooling of plasma bubbles ablated by main laser pulses. Radiative cooling of the high-Z plasmas might collimate the plasma jets as well. Having some geometrical similarities with young stellar object (YSO) jets, the jets have potential application to simulating YSO jets in laboratories. (authors)

[en] An increase has been observed in the conversion efficiency (η_k) from laser energy to K_α X-ray energy produced by 60 fs frequency-doubled high-contrast laser pulses focused on a Cu foil, compared to the case with fundamental laser pulses. The value of η_k shows a strong dependence on the nonlinearly modified rising edge of the laser pulse. It reaches a maximum for a 100 fs negatively modified pulse. The efficient heating of the hot electrons leads to the enhancement of η_k. This demonstrates that high-contrast lasers are an effective tool for optimizing η_k, through increasing the quantity of hot electrons by vacuum heating. These results have been published in Phys. Rev. Lett., 2008,100:045004. (authors)

[en] Laser-produced line plasmas were used as a broadband source of soft X rays and a stigmatic grazing incidence grating spectrometer to measure the normal incidence reflectance of concave multilayer mirrors in the 20∼40 nm spectral region. The measurements of the reflectance made on a C/Al multilayer show a little lower than the calculated results and indicate a normal incidence peak reflectance of about 22% at 28.5 nm