The KSTAR (Korea Superconducting Tokamak Advanced Researc pursued to develop key technologies for superconducting tokamak operation and to contribute to a few research items for ITER relevant issues. ...As a result, the KSTAR achieved highly confined mode (H-mod in 2010 campaign and successfully demonstrated suppression of Edge Localized Mode (ELM) using n=1 Resonant Magnetic Perturbation (RMP) coils. The KSTAR is also initiating machine performance based on the designed machine parameters. The plasma current we achieved was 1 MA, and longest plasma pulse length has been extended to 10 s. In spite of limited heating power to 3.5 MW, several key actuators satisfactorily supported to implement a few scientific researches such as ELM control. On the basis of big progress in both the plasma performance and the experimental results, the KSTAR operation will explore key scientific and technical research issues under steady state operation condition in phase-2 operation.
The diagnosis of cancer is associated with the occurrence of psychopathological symptoms, which cause even more difficulties to patients. Scientific research demonstrates that creativity could help ...increase the general population's quality of life and regulate their negative emotions, but only a few studies are available on the link between creativity and the regulation of patients’ respective experience. This study aims at (1) measuring the impact of creativity on the patient's level of depression and quality of life and (2) evaluating the psychopathological profile of the creative person. Thirty-five subjects undergoing chemotherapy treatment (age: 61+11) took part in this study. The experimental protocol is composed of creativity, depression and QoL tests. The results show that creativity is negatively correlated with depression level and positively with QoL (r=−45; P=<.05 and r=.54; P=<.01 respectively). The linear regressions show that creativity is a variable, which predicts a high QoL (F=13.83; P=.001). Also, 29.5% of the QoL variability is explained by creativity. A cluster analysis sorted out three different groups: very creative persons (VCP); mildly creative persons (MCP); slightly creative persons (SCP). VCPs have a significantly lower level of depression and have a better QoL compared to SCPs. MCPs have a level of depression between the other groups and a similar level of QoL than VCPs. These results suggest that creativity could have a noticeable influence on how patients experience their cancer. Further studies on this phenomenon will be necessary for creativity to be taken into account for psychological follow-up in oncology.
Abstract
ITER will operate with a tungsten divertor, a material featuring surface morphology changes when exposed to helium plasmas, in particular the formation of the so called tungsten fuzz under ...specific conditions. Investigating interactions between tungsten plasma facing components and helium plasmas in a tokamak environment is therefore a key point to consolidate predictions for the ITER divertor performance and lifetime. To this end, a dedicated helium campaign was performed in the full tungsten WEST tokamak, cumulating ∼2000 s of repetitive L mode discharges. It is shown that conditions for tungsten fuzz formation, as derived from linear devices experiments (incident helium energy
E
inc
> 20 eV, helium fluence >10
24
He/m
2
, surface temperature
T
surf
> 700 °C), were met in the outer strike point (OSP) area of the inertially cooled tungsten divertor elements of WEST. Preliminary inspection of the components after the campaign did not show visible signs of surface modification, but points to significant net erosion in the OSP area. An extensive post mortem analysis is now ongoing to confirm these first indications. These results underline that the complex balance between erosion/redeposition (in particular linked to impurities) and tungsten fuzz formation needs to be taken into account in tokamak conditions.
The mission of HL-2A is to explore the key physical topics relevant to ITER and to the advanced tokamak operation (e.g. the operation of future HL-2M), such as the access of H-mode, energetic ...particle physics, edge-localized mode (ELM) mitigation/suppression and disruption mitigation. Since the 2016 Fusion Energy Conference, the HL-2A team has focused on the investigations on the following areas: (i) pedestal dynamics and L-H transition, (ii) techniques of ELM control, (iii) turbulence and transport, (iv) energetic particle physics. The HL-2A results demonstrated that the increase of mean shear flow plays a key role in triggering L-I and I-H transitions, while the change of flow is mainly induced by the ion pressure gradient. Both mitigation and suppression of ELMs were realized by laser blow-off seeded impurity (Al, Fe, W). The 30% Ne mixture supersonic molecular beam injection seeding also robustly induced ELM mitigation. The ELMs were mitigated by low-hybrid current drive. The stabilization of m/n = 1/1 ion fishbone activities by electron cyclotron resonance heating was found on the HL-2A. A new m/n = 2/1 ion fishbone activity was observed recently, and the modelling indicated that passing fast ions dominantly contribute to the driving of 2/1 fishbone. The non-linear coupling between the toroidal Alfven eigenmode and tearing mode (TM) led to the generation of a high frequency mode with the toroidal mode number n = 0. The turbulence was modulated by TM when the island width exceeds a threshold and the modulation is localized merely in the inner area of the islands. Meanwhile, turbulence radial spread took place across the island region.
The interaction between the lower hybrid current drive (LHCD) launchers and the plasma has been studied during long pulse, high power operation in the Tore Supra tokamak. The main diagnostics used ...for characterising the plasma–launcher interaction are calorimetry of the energy extracted by the launchers and infrared (IR) imaging of the launchers and their side limiters. The calorimetry has allowed to identify three different heat sources on the LHCD launchers, namely the RF losses in the waveguides, a fraction (∼0.8%) of the total injected energy and, finally, fast ion losses during ion cyclotron resonance heating (ICRH), accounting for ∼1% of the injected ICRH energy. The interaction by fast ions is identified by infrared imaging of the LHCD launchers as a localised hotspot on the ion drift side, below or at the mid-plane.
Abstract
High power experiments, up to 9.2 MW with LHCD and ICRH, have been carried out in the full tungsten tokamak WEST. Quasi non inductive discharges have been achieved allowing to extend the ...plasma duration to 53 s with stationary conditions in particular with respect to tungsten contamination. Transitions to H mode are observed, and H-modes lasting up to 4 s have been obtained. The increase in stored energy is weak since the power crossing the separatrix is close to the L–H threshold. Hot L mode plasmas (central temperature exceeding 3 keV) with a confinement time following the ITER L96 scaling law are routinely obtained. The weak aspect ratio dependence of this scaling law is confirmed. Tungsten accumulation is generally not an operational issue on WEST. Difficulty of burning through tungsten can prevent the discharge from accessing to a hot core plasma in the ramp-up phase, or can lead to rapid collapse of the central temperature when radiation is enhanced by a slight decrease of the temperature. Except a few pulses post-boronization, the plasma radiation is rather high (
P
rad/
P
tot
∼ 50%) and is dominated by tungsten. This fraction does not vary as the RF power is ramped up and is quite similar in ICRH and/or LHCD heated plasmas. An estimate of the contribution of the RF antennas to the plasma contamination in tungsten is given.
A 3.7-GHz 750-kW klystron in continuous-wave (CW) operation is under development to upgrade the lower hybrid RF power of Tore Supra up to 12 MW. Four different operating modes are required: diode ...regime (1680-kW dc of beam power in the collector), 750-kW RF on matched load, 700-kW min all phases on voltage standing wave ratio (VSWR) 1.4:1 (plasma conditions), and around 400-kW pulsed mode on VSWR 3.0:1 (for antenna conditioning phase). The klystron is equipped with a diode type electron gun, a five-cavity RF structure with a highly efficient cooling system for the output cavity, a single tapered waveguide, a single BeO disc RF window, and a large diameter hypervapotron collector. Two breadboard models have been built and tested. At 50% duty cycle (with 5-ms pulse length), an RF output power of 770 kW has been measured at a beam voltage of 75 kV and a beam current of 22 A. The efficiency is 46.6% and the gain is 54 dB. On VSWR 1.4, a minimum output power of 660 kW has been obtained and the klystron is stable at all phases. In CW operation, the klystron has produced an output power of 680 kW. The limitation is due to excessive body power. The final prototype with an improved beam optics and thermal design will be ready in the second half of the year 2004.
Hepatitis B virus core protein (HBc) is an important serology marker of hepatitis B infection and patient follow-up. It is an
M
r 21 000 protein, which has the intrinsic capacity to self-assemble as ...a capsid-like particle. The hepatitis B core protein has been expressed in
Escherichia coli and
Pichia pastoris (three different constructions) in order to select a HBc recombinant antigen suitable for serodiagnosis requirements with a cost effective downstream strategy. The expression and purification of the different forms of recombinant HBc have been described. For the last step, ultracentrifugation and size-exclusion chromatography were compared. The morphology of these capsids was observed using an electron microscope. Our data shows that HBc antigen is produced in large quantities in
E. coli but some contaminants remained which were associated with the
E. coli HBc protein after ultracentrifugation or size-exclusion chromatography. The ultracentrifugation enables a higher purity of HBc antigen to be obtained than size-exclusion chromatography but the latter enables a higher recovery rate.
P. pastoris enables the expression and extraction of a highly purified HBc antigen suitable for diagnostic purposes.
Toward a LHCD system for ITER Bibet, Ph; Beaumont, B.; Belo, J.H. ...
Fusion engineering and design,
11/2005, Letnik:
74, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
On ITER, the LH system aims at supplying 20
MW CW for controlling the
q-profiles in partially and fully non-inductive steady-state operation (9
MA). The designed LH system relies on a transmitter ...made of 24 5
GHz 1
MW klystrons linked to one antenna based on the passive active multijunction (PAM) concept, via a 60
m long oversized circular transmission line. Through a common European effort including several associations (CEA, ENEA, UKAEA, IST, TEKES and IPP-CZ) many outstanding problems have been solved: coupling has been achieved on JET in a physics scenario similar to ITER, a PAM has been tested with success on the FTU plasma. The reliability of LH for long pulse operation has been ascertained on Tore Supra. In order to routinely realise long pulse operation (1000
s), the Tore Supra LH system is being refurbished within the CIMES project framework where the transmitter is to be equipped with 16 klystrons 700
kW 1000
s at a frequency of 3.7
GHz. A new LH launcher based upon the PAM concept has been studied, designed and is actually under realisation.
Nitrogen (N2) will be used in ITER to enhance the radiative fraction to ~90%, thereby cooling the edge plasma and preventing damage to the plasma-facing components. However, the reactivity of N2 with ...hydrogen isotopes can lead to the formation of tritiated ammonia (NT3). This should be considered in terms of the in-vessel tritium inventory, the regeneration of the cryo pumps, and the processes in the ITER de-tritiation plant. In the 'W' Environment in Steady-state Tokamak (WEST), a series of long L-mode discharges (~50 s), with a constant N2 seeding from the outer strike point region has been performed on the upper actively cooled divertor. In the absence of active pumping, the N2 balance shows steady-state retention during plasma discharge, and is partially (~35%) released in between discharges. Although a significant amount of N2( 18.65 Pa m3) has been injected, the wall still exhibited N2 pumping capabilities. Under these conditions, as long as this N2 reservoir is not saturated, there is not enough N available for the detectable threshold of ND3 formation to be reached. In these WEST experiments, no ammonia is detected during the pulse or after the pulse in the outgassing phase. These results are consistent with and complementary to the N2 seeded experiments performed in the Joint European Torus (JET) with its ITER-like wall and in the Axially Symmetric Divertor Experiment (ASDEX) upgrade.
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