[en] The 2.45 GHz lower hybrid current drive systems have been established at two output microwave power levels, 100 KW and 500 KW, for the LHCD experiments in HT-6B and HT-6M tokamaks respectively. Two kinds of cross field microwave tubes, magnetron and CFA amplifier, were adopted as the long pulse microwave sources for 100 KW system and 500 KW system respectively. The pulse duration of these tubes can reach about 0.1 second. These microwave tubes can operate at much lower anode voltage than that of klystrons. The slow wave antennas in these two LHCD systems both are the multijunction grills, of which one is 1 x 8 multijunction grill with fixed phase shifts between adjacent subwaveguides, another is 2 units of 1 x 12 multijunction grills with changeable phase shifters and bidirectional couplers in every subwaveguides. The informations about wave coupling and wave reflection can taken from these couplers. The N_parallel spectrum of the grill can be chosen arbitrarily using these phase shifters. The 100 KW LHCD system has been used for HT-6B tokamak experiment and the effects of current drive with and without the assistance of Ohmic heating are both obvious. The setting up of 500 KW system will be fulfilled at the end of this year. (author). 16 refs, 6 figs, 4 tabs

[en] The composition of HT-7 LHCD system along with its protection systems is introduced. It is very important to run the LHCD system safety and efficiently

[en] The results of transformer recharging experiments by means of lower hybrid current drive (LHCD) on HT-7 superconducting Tokamak are summarized and analyzed on the basis of a simple transformer circuit. A steady-state plasma can be maintained at about 50 kA by LHCD while the primary coils of Tokamak transformer is recharged. During the recharge phase, a constant plasma loop voltage about -0.05 V keeps for about 1.0 s and the magnetic flux of the Tokamak transformer changes from 0.645 to 0.615 Vs. A maximum recharging efficiency of 1.25% has been obtained at a line averaged electron density of 0.5 x 10¹⁹ m^-3. In addition, full non-inductive current drive experiment has been realized on HT-7 Tokamak

[en] The technology of the phase adjustment of a lower hybrid wave on HT-7 superconducting tokamak is described and the calculating method involved in the technology is introduced. The design method of hardware and software is also presented. In addition, a series of experimental results are reported

[en] Highlights: • Orthogonal test method on microporous layer composition optimization is studied. • Nine orthogonal microporous layer s are prepared and tested on cell. • Hydrophobic agent content has the least impact on cell performance. -- Abstract: The microporous layer of gas diffusion layer plays an important role in water management of polymer exchange membrane fuel cells. Many factors affect the performance of the microporous layer, and these factors are interrelated. In this work, the orthogonal test method is used to study the effects of four factors including hydrophobic agent, the ratio of carbon powder to hydrophobic agent, carbon powder and microporous layer loading. Nine experiments with four factors and three levels are carried out. The effects of these different factors on the microporous layer are studied. The polarization curves and electrochemical impedance spectroscopy of fuel cells are tested and the scanning electron microscopy, contact angle and pore size distribution of MPL are characterized to prove that the conclusions obtained by orthogonal tests are correct and reliable. It is observed that carbon powder, hydrophobic agent and microporous layer loading have significant effects on the performance of fuel cell than that of the ratio of carbon powder to hydrophobic agent. These three factors mainly influence the cells performance by affecting the ohmic resistance and mass transfer resistance. This work provides a reference for the rapid optimization of microporous layer composition and hence improve the water management of the fuel cell.

[en] It has been found that lower hybrid waves excite various sawtooth oscillations during the HT-7 tokamak discharges. The authors present the results of lower hybrid current drive (LHCD) on sawtooth activity in a series of experiments with 2.45 GHz, 1MW LH system on HT-7 superconducting tokamak. In these experiments, usually LH power is between 200-400 kW, 2≤N_//^p≤3(ΔN_// = 0.8), and rf pulse in 500 ms. Sometimes, the sawtooth oscillation is accompanied by a wide range of magnetohydrodynamic activity in the plasma central region, normally with a m = 1/n = 1 mode. A LHCD partial suppression of sawtooth, a lengthening sawtooth and a saturation of sawtooth oscillations are also observed during the experiments

[en] A stable ECR plasma was produced and sustained in HER mirror using 2450MHz Whistler wave. The parameters of the ECR plasma and their chaining characters were studied in detail and were compared with those of the DC discharge plasmas. The conclusion is that the ECR plasma is a high ionizability, low temperature, middle density plasma, its peak density may much exceed the cutoff density of the pump wave (when ω = ω_pe) and arrive at the order of 10¹²cm^-3. The ECR plasma includes some high energy hot electrons (20Kev-200Kev) and middle energy warm electrons (< 20Kev). Those two kinds of electron created some strong X-ray emissions in a wide frequency range. The ECR plasma has higher edge density and can strongly interact with the wall. (author). 9 refs, 17 figs

[en] Ramp-up experiments by means of lower hybrid wave on HT-7 superconducting tokamak have been performed and analyzed. A ramp-up rate of over 300 kA/s is obtained and a conversion efficiency of over 10% has been achieved during the ramp-up phase. The study of the dependence of conversion efficiency on plasma density shows that the conversion efficiency is affected by the driven current, which is mainly dominated by the competition of impurity concentration with wave accessibility condition. In addition, the effect of current profile may play an important role in determining the conversion efficiency

[en] Batch supercritical water oxidation (SCWO) equipment was used to study the treatment of discarded cation resin water suspension under supercritical conditions. The effects of reaction temperature, reaction pressure, residence time, and coefficient of peroxide on the removal rate of COD (chemical oxygen demand) were investigated experimentally. At the same time, the transfer of simulated nuclides under supercritical conditions was studied. Through orthogonal test, the most significant factors influencing the reaction system are ranked as follows: reaction temperature > residence time > peroxide coefficient > reaction pressure. The experiment shows that the degradation rate of COD of cationic resin is 99.5% under the conditions of reaction temperature 520℃, reaction pressure 23 MPa, residence time 30 min, pH = 7, and oxidation coefficient 3. The cesium and cobalt ions were used to simulate the nuclear radioactive material in the discarded resin slurry. Under the optimal conditions, the cesium and cobalt ions were separated from the treated solution by 99.8%. (authors)

[en] Lower hybrid current drive experiments on the HT-7 device have been carried out by scanning the following parameters: central line averaged electron density (n_e = 0.6 - 2.0 x 10¹⁹ m^-3) and toroidal magnetic field (B_t = 1.62 - 2.0 T). The dependence of current drive efficiency on these parameters has been studied and the experimental curves of current drive efficiency as a function of n_e and B_t have also been obtained. From these experimental results, it can be seen that current drive efficiency rises with the increase of toroidal magnetic field. As plasma density increases, the current drive efficiency first increases to a certain value, then gradually decreases, that is, there exists an optimized density regime where a better drive efficiency can be obtained. The analysis shows that the current drive efficiency is mainly affected by wave accessibility and impurity concentration, and the competition of these two factors determines the current drive efficiency