[en] A carbon dioxide laser Thomson scattering system has been installed on the HT-6M tokamak. This system is briefly described here. It has been used to investigate turbulent density fluctuations with peak amplitudes between 100 kHZ and 400 kHZ in ohmically heated and in ion-cyclotron-heated plasmas. It was found that ion-cyclotron heating affects the fluctuation level and the spectral distribution significantly. 9 refs, 4 figs

[en] A hybrid current drive scheme is investigated for its potential utilization with a tokamak reactor. In this scheme, the toroidal plasma current I_P is maintained steady by the hybrid use of the tokamak transformer and non-inductive current drive (NICD). I_P is driven by the inductive electric field E in the half-cycle of the high density burn phase of tokamak reactor. When the direction of E is reversed in the next half-cycle as in a.c. operation, the NICD power is applied to overcome the fact that the reversed E impedes I_P and to maintain the direction and magnitude of I_P as unchanged. A small amount of NICD power is found to be necessary if n is decreased to a low level in this half-cycle. In this hybrid operation scheme, there are no problems of periodic ionization loss, breakdown and current ramp that is associated with a.c. operation scheme. Also, the requirement for transformer flux swing is found to be much lower than that in the a.c. scheme

[en] The small scale density fluctuations in the interior of HT-6M Ohmic plasma have been studied by CO₂ laser collective scattering system in deuterium discharges covering a wide range of bar nq_a (chord-average density times safety factor at the limiter) and energy confinement time. The relative density fluctuation level in the interior is inversely proportional to the toroidal magnetic field and average density, and the energy confinement time τ_E decreases with the fluctuation level increasing in the region where τ_E linearly increases with bar nq^0.5_a and satisfies the Goldston scaling law. It is suggested that the microturbulence in the interior zone is responsible for anomalous transport in tokamaks

[en] We propose a type of GaN-LED based on the optimized multilayered lamellar micro-grating. This structure contains a SiO₂ inserted-layer, an Ag grating and a TiO₂ film cover-layer. The Ag grating with optimized parameters is used to enhance the internal quantum efficiency and the transmission simultaneously. The TiO₂ layer with optimized thickness is utilized to improve the transmission through the multilayered structure. The inserted SiO₂ layer suppresses the power loss of Ag grating and further promotes the transmission. The properties of the guided-modes and Purcell effect in this structure are analyzed. The photoluminescence experiment indicates that its peak intensity of top-emission is about 2.2 times greater than the naked sample.

[en] A simple and reliable temperature sensing method with high sensitivity is proposed. ZnO composite graphene sensitive materials with different shapes are successfully prepared by hydrothermal method and characterized by scanning electron microscpoy. The sensor is fabricated by coating the singlemode-taper multimode-singlemode with ZnO composite graphene. The effects of different shapes of ZnO composite graphene on the sensitivity of temperature sensors are further investigated. The electron migration rate of ZnO composite graphene is changed by temperature change. Furthermore, the surface refractive index of the optical microfiber changes. The results show that the sensor with floriated ZnO composite graphene exhibits a high sensitivity of 282.48 pm °C for temperature ranging from 30 °C to 48 °C, which provides a novel and convenient platform for temperature sensing. (paper)

[en] Highlights: • A electro-hydraulic energy-saving system is proposed for energy recovery and regeneration. • A parametric rule-based strategy of the proposed system is developed for real-time control. • The proposed energy-saving system prototype is equipped on a 23-ton hydraulic excavator. • Experiments studies show that about 17.6% energy can be saving by this system. • The system is evaluated from multiple perspectives of efficiency, performance and comfort. -- Abstract: Energy recovery and regeneration comprise an effective way to improve hydraulic excavator fuel economy. This paper proposes a novel electro-hydraulic energy-saving system to integrate recovery and regeneration devices. The working conditions of excavators and system configuration of the proposed system are analyzed. A parametric rule-based strategy is implemented to real-time control. A energy-saving prototype is developed for a 23-ton hydraulic excavator. Several tests are carried out to evaluate the prototype from the perspectives of energy consumption, action performance, and system comfortableness. Results show that the excavator equipped with the energy-saving system can be reduced by approximately 17.6% compared with a conventional one. The braking time of the boom-lowering process is about 1.87 times that of the conventional system. The electric motor is the main vibration source, and the impact of hydraulic system shock on comfortableness is indirect. The results are important reference for further system optimization.

[en] Temperature dependent high-resolution angle-resolved photoelectron spectroscopy has been performed on the quasi-two-dimensional compound ZrTe₅, a metal at low temperatures (T ≤ 4.2K) that exhibits a maximum resistivity at a temperature (T_c), concomitant with a sign change of the thermopower. A semiconducting gap has been observed in the photoemission spectra, where the valence band maximum shifts upward from 82 meV (75 K) to 40 meV (170 K) as a function of temperature. The band shifts are accompanied by small band distortions. Based on the photoemission experiments, in conjunction with the metallic character of ZrTe₅ at low temperatures, we have modelled the thermopower of ZrTe₅ by treating it as a metal at low temperatures and a semiconductor at elevated temperatures. (letter to the editor)