Quasi-optical design for the cross-polarization scattering diagnostic on the HL-3 tokamak.

As the plasma beta (ß) increases in high-performance tokamaks, electromagnetic turbulence becomes more significant, potentially constraining their operational range. To investigate this turbulence, a cross-polarization scattering (CPS) diagnostic system is being developed on the HL-3 tokamak for simultaneous measurements of density and magnetic fluctuations. In this work, a quasi-optical system has been designed and analyzed for the Q-band CPS diagnostic. The system includes a lens group for beam waist size optimization, a rotatable wire-grid polarizer for polarization adjustment, and a reflector group for measurement range regulation and system response enhancement. Laboratory tests demonstrated a beam radius of order 4 cm at the target measurement location (near the plasma pedestal), cross-polarization isolation exceeding 30 dB, and poloidal and toroidal angle adjustment ranges of ±40° and ±15°, respectively. These results verify the system's feasibility through laboratory evaluations. The quasi-optical system has been installed on the HL-3 tokamak during the 2023 experimental campaign to support the development of CPS diagnostics.

Plasma position measurements by O-mode and X-mode reflectometry systems in tokamak plasmas.

Plasma Position Reflectometry (PPR) is planned to provide plasma position and shape information for plasma operation in future fusion reactors. Its primary function is to calibrate the drift of the magnetic signals due to the integral nature of magnetic measurement. Here, we attempt to measure plasma position using ordinary mode (O-mode) and extraordinary mode (X-mode) reflectometry systems on two tokamaks. A new physical model based on the phase shift is proposed to deduce the relative movement of the cut-off layer without density inversion. We demonstrate the plasma position measurements by absolute measurement from density profile inversion and relative measurement from phase shift. The combination of X-mode and O-mode reflectometers can minimize the limitations of single polarization reflectometry and further increase the accuracy of plasma position measurement. These results could provide an important technical basis for the further development of a real-time control system based on PPR.

Preliminary results of the 105 GHz collective Thomson scattering system on HL-2A.

A 105 GHz collective Thomson scattering (CTS) diagnostic has been successfully developed for fast-ion measurements on the HL-2A tokamak, and it has been deployed during an experimental campaign. Enhanced signals exhibiting synchronous modulation characteristics have been observed across all CTS channels upon the launch of a modulated probe wave. Results show that the intensity of the CTS signal increases with Neutral Beam Injection (NBI) power and is proportional to neutron count, indicating that the scattering signal contains a contribution from fast ions. Compared with the signal without NBI, the enhanced scattering spectrum due to NBI is slightly wider than the predicted fast ion range. Such broadening might be attributed to the heating effects of the gyrotron.

A gamma ray spectrometer with Compton suppression on the HL-2A tokamak.

A new broad-energy, high-resolution gamma ray spectrometer (GRS) with Compton suppression function has been developed recently in the HL-2A tokamak to obtain the gamma ray information in the energy range of 0.1-10 MeV. This is the first time to develop an anti-Compton GRS for a magnetic confinement fusion device. The anticoincidence detector consists of a large-volume high purity germanium (HPGe) crystal (Φ63 × 63 mm2) as the primary detector and eight trapezoidal bismuth germinate (BGO) scintillators (trapezoid crystal with 30 mm thickness) as the secondary detector. The anti-coincidence data processing is implemented by a digital-based data acquisition system with fast digitization and software signal processing technology. Using radioisotope gamma ray sources and Monte Carlo N-Particle code, the energy and efficiency of the spectrometer have been calibrated and quantitatively tested. The Compton continuum suppression factor reaches 4.2, and the energy resolution (Full Width at Half Maximum) of the 1.332 MeV full energy peak for 60Co is 2.1 keV. Measurements of gamma ray spectra with Compton suppression using the spectrometer have been successfully performed during HL-2A discharges with different conditions. The performance of the spectrometer and the first experimental results are presented in this paper.

Development of solid state terahertz interferometer for the first plasma on HL-2M tokamak.

A solid state terahertz interferometer has been developed on the recent commissioned HL-2M tokamak. It can work in a wide frequency region of 220-325 GHz, and the terahertz wave is generated from a low frequency phase locked voltage controlled oscillator with the frequency multiplying technique. A phase processor based on field programmable gate array (FPGA) technology is designed for the heterodyne interferometer, and it contributes to real-time display of electron density. To extract phase information, a novel numerical algorithm related to fast Fourier transform is written on the FPGA chip and enables one to obtain phase shift without being affected by amplitude variation induced by plasma absorption or frequency modulation from the outer electromagnetic environment. The interferometer achieves minimum measurable electron density in the order of 1016 m-3. With the plasma diagnosis, electron density and low frequency tearing mode have been measured during the first experimental campaign.

A remote gain controlled and polarization angle tunable Doppler backward scattering reflectometer.

Remote control of the diagnostic systems is the basic requirement for the high performance plasma operation in a fusion device. This work presents the development of the remote control system for the multichannel Doppler backward scattering (DBS) reflectometers. It includes a remote controlled quasi-optical system and a remote intermediate frequency (IF) amplifier gain control system. The quasi-optical system contains a rotational polarizer, its polarization angle is tunable through a remote controlled motor, and it could combine the microwave beams with a wide frequency range into one focused beam. The remote IF gain control system utilizes the digital microcontroller (MCU) technique to regulate the signal amplitude for each signal channel. The gain parameters of amplifiers are adjustable, and the feedback of working status in the IF system will be sent to MCU in real time for safe operation. The gain parameters could be controlled either by the Ethernet remote way or directly through the local control interface on the system. Preliminary experimental results show the effectiveness of the remote controlled multichannel DBS system.

[Application of artificial intelligence-assisted diagnosis for cervical liquid-based thin-layer cytology].

Objective: To explore the application value of artificial intelligence-assisted diagnosis system for TBS report in cervical cancer screening. Methods: A total of 16 317 clinical samples and related data of cervical liquid-based thin-layer cell smears, which were obtained from July 2020 to September 2020, were collected from Southern Hospital, Guangzhou Huayin Medical Inspection Center, Shenzhen Bao'an People's Hospital(Group) and Changsha Yuan'an Biotechnology Co., Ltd. The TBS report artificial intelligence-assisted diagnosis system of cervical liquid-based thin-layer cytology jointly developed by Southern Medical University and Guangzhou F. Q. PATHOTECH Co., Ltd. based on deep learning convolution neural network was used to diagnose all clinical samples. The sensitivity,specificity and accuracy of both artificial intelligence-assisted diagnosis system and cytologists using artificial intelligence-assisted diagnosis system were analyzed based on the evaluation standard(2014 TBS). The time spent by the two methods was also compared. Results: The sensitivity of artificial intelligence-assisted diagnosis system in predicting cervical intraepithelial lesions and other lesions (including endometrial cells detected in women over 45 years old and infectious lesions) under different production methods, different cytoplasmic staining and different scanning instruments was 92.90% and 83.55% respectively, and the specificity of negative samples was 87.02%, while that of cytologists using artificial intelligence-assisted diagnosis system was 99.34%, 97.79% and 99.10%, respectively. Moreover, cytologists using artificial intelligence-assisted diagnosis system could save about 6 times of reading time than manual. Conclusions: Artificial intelligence-assisted diagnosis system for TBS report of cervical liquid-based thin-layer cytology has the advantages of high sensitivity, high specificity and strong generalization. Cytologists can significantly improve the accuracy and work efficiency of reading smears by using artificial intelligence-assisted diagnosis system.

[Blood pressure control and influencing factors in hypertension patients with metabolic syndrome].

Objective: To investigate the blood pressure control and its influencing factors in hypertension patients with MS. Methods: Between January 2017 and December 2018, more than 78 000 residents aged 35-75 years selected through convenient sampling were invited to participant in China Patient-Centered Evaluative Assessment of Cardiac Event Million Persons Project in Fujian province, physical and laboratory tests were conducted for them, and their basic information were recorded. A total of 5 281 hypertension patients with MS were included in the study. Results: The treatment rate of hypertension patients with MS was 55.5%, and the control rate was 7.2%. The control rate was higher in patients who were older, women, had advanced education level, had history or family history of cardiovascular disease. The results of multivariate analysis indicated that living area (urban or rural), cardiovascular history, diabetes, urine protein, BMI had impacts on both treatment and control of hypertension. Family history of cardiovascular disease, age, self-management of hypertension, dyslipidemia, waist circumference and drinking had impacts on the treatments, and gender had effects on the control. Conclusions: The treatment rate of hypertension patients with MS was unsatisfactory and the control rate was low. Intervention should be strengthened in rural area, males and young age groups, and activity of self-management group of hypertension should be conducted regularly.

Experimental study of perturbative particle transport in the HL-2A tokamak.

Perturbative particle transport experiment has been performed in the HL-2A tokamak by using supersonic molecular beam injection (SMBI) as an external particle source. The spatiotemporal evolution of edge density perturbation is traced and the particle source and the flux-gradient relation are obtained experimentally. The flux-gradient relation is found to be far from the diffusive model and three different transport processes are revealed, including pinch-dominant process, diffusion-pinch process and intermittent decays.

An eight-channel correlation electron cyclotron emission diagnostic for turbulent electron temperature fluctuation measurement in HL-2A tokamak.

A new correlation electron cyclotron emission (CECE) diagnostic has recently been installed on the HL-2A tokamak in order to study electron temperature fluctuations. Eight radial locations are measured simultaneously through eight pairs of correlated channels. Multiplexers are employed in the intermediate frequency section instead of the conventional separated filter banks to meet strict cross-isolation specifications and lower insertion loss. Relative electron temperature fluctuations are observed by CECE for the first time on the HL-2A by using the spectral decorrelation method. The achieved minimum detectable fluctuation level is up to (T̃e/Te)min∼0.5%. When studying electron temperature fluctuations in the core region with gas puffing, the cross-power spectra show that the amplitude of the electron temperature fluctuation increases in a high temperature and low density plasma. Further analysis demonstrates that the electron temperature gradient ∇Te drives the electron temperature fluctuations together with electron heat transport.

Aryl hydrocarbon receptor polymorphisms are associated with dry skin phenotypes in Chinese patients with atopic dermatitis.

BACKGROUND: Epidermal barrier dysfunction is the initial event in the development of atopic dermatitis (AD). Recent studies have identified a crucial role for the aryl hydrocarbon receptor (AHR) in controlling the gene expression of filaggrin and other skin barrier proteins, suggesting an underlying association between AHR and AD pathogenesis. AIM: To investigate the role of AHR gene polymorphisms in the susceptibility to AD and in AD-associated phenotypes. METHODS: We enrolled 487 patients with AD, 210 patients with psoriasis and 226 healthy controls (HCs) from the Han Chinese population, and genotyped two AHR single-nucleotide polymorphisms (rs10249788 and rs2066853) by PCR and subsequent DNA sequencing. RESULTS: The AHR rs10249788 and rs2066853 polymorphisms were found in both sets of patients (AD and psoriasis) and in HCs, but no significant differences were detected in genotype or allele frequencies between the three groups. However, patients with AD with the rs10249788 (CT/TT) or rs2066853 (AG + AA) genotype were more likely to have severe dry skin scores. In the stratification analysis, the AHR rs2066853 (AG + AA) and rs10249788 (CT + TT) genotypes could predict a higher risk of severe dry skin phenotypes in the male, early-onset and allergic rhinitis subgroups. Furthermore, the combined rs10249788 (CT + TT) and rs2066853 (AG + AA) genotypes led to a higher risk for severe dry skin in patients with AD. CONCLUSION: AHR polymorphisms are not associated with the risk of AD; however, they may predict a dry skin phenotype in patients with AD.

Observation of Double Impurity Critical Gradients for Electromagnetic Turbulence Excitation in Tokamak Plasmas.

The impact of impurity ions on a pedestal has been investigated in the HL-2A Tokamak, at the Southwestern Institute of Physics, Chengdu, China. Experimental results have clearly shown that during the H-mode phase, an electromagnetic turbulence was excited in the edge plasma region, where the impurity ions exhibited a peaked profile. It has been found that double impurity critical gradients are responsible for triggering the turbulence. Strong stiffness of the impurity profile has been observed during cyclic transitions between the I-phase and H-mode regime. The results suggest that the underlying physics of the self-regulated edge impurity profile offers the possibility for an active control of the pedestal dynamics via pedestal turbulence.

[Retroperitoneoscopic renal pedicle lymphatic disconnection for chyluria via extra-adipose capsule].

OBJECTIVE: To evaluate the clinical effect of retroperitoneoscopic renal pedicle lymphatic disconnection via extra-adipose capsule in the management of chyluria and to discuss the management of its complications. METHODS: From August 2013 to June 2008, five patients with chyluria were admitted. All the patients were female, aged from 26 to 73 years, and disease course from 1 to 10 years. All the five patients had complained of intermittently voiding milky urine with varying degrees of weight loss, and fatigue, of whom two presented with flank pain and one with anemia. Their urine chyle tests were confirmed to be positive. Preoperative cystoscopy found that chyluria was from the left side in 3 cases,and from the right side in 2 cases. Their proteinuria ranged from + to ++++. All the cases had been treated with the modified procedure by which lymphatic ligation was performed to hilar vessels and proximalureter via extra-adipose capsule without disconnection of perirenal fat tissues. The operation time, intraoperative blood loss, postoperative intestinal function recovery, catheter time, drainage tube removal time and complications during operation were collected. RESULTS: All the five cases were performed successfully. The operation time ranged from 75 to 170 minutes, mean (126.0±39.6) minutes, with the intraoperative blood loss 20 to 60 mL, mean (38.0±16.4) mL, and the postoperative intestinal function recovery time 1 to 3 days, mean (1.9±0.4) days. The catheter time was 1 to 4 days, mean (2.1±0.3) days and the drainage tube removal time ranged from 3 to 15 days, mean (9.3±1.8) days. Postoperatively lymphorrhagia was found in two cases. No renal vessels injury occurred during operation. Chyluria of all the patients disappeared on the operation day with negative chyluria test after surgery. Furthermore, urine test revealed that proteinuria was totally negative. No recurrence was detected in our patients in the 9 to 31 months' follow-up. CONCLUSION: This modified procedure does not have to disconnect perirenal fat tissues and nephropexy during operation. It was characterized with shorter operation time, definitive effect and fewer complications.

[Estimation of underreporting rate of death cases in disease surveillance system of Fujian province using propensity score weighting method, 2012-2014].

Objective: To understand the underreporting of death cases and related factors in disease surveillance system of Fujian province. Methods: We carried out a field underreporting survey in 20 disease surveillance sites selected through stratified cluster random sampling during 2012-2014. The related factors of underreporting were analyzed by using logistic regression method. Propensity score weighting method was used to calculate the underreporting rate in different groups classified by year, urban/rural areas, gender, age and death cause variables. Results: The overall underreporting rate was 9.21%(95%CI: 9.06%-9.39%) after adjusting by propensity score weighting method. The underreporting rate was higher in rural area (11.55%, 95%CI: 11.30%-11.81%) than in urban area (6.64%, 95%CI: 6.50%-6.78%). The underreporting rate was highest in age group 0-14 years (36.29%, 95% CI: 34.23%-38.67%) and lowest in age group ≥65 years (7.91%, 95% CI: 7.78%-8.03%). The underreporting rate was higher in people died of perinatal disease, congenital anomalies and injury. Conclusion: The underreporting rates were different between different groups classified by urban/rural areas, age and death cause variables. Propensity score weighting method can be used to adjust underreporting rate of death cases in mortality surveillance in Fujian.

[Retroperitoneoscopic renal pedicle lymphatic disconnection for chyluria via extra-adipose capsule].

OBJECTIVE: To evaluate the clinical effect of retroperitoneoscopic renal pedicle lymphatic disconnection via extra-adipose capsule in the management of chyluria and to discuss the management of its complications. METHODS: From August 2013 to June 2008, five patients with chyluria were admitted. All the patients were female, aged from 26 to 73 years, and disease course from 1 to 10 years. All the five patients had complained of intermittently voiding milky urine with varying degrees of weight loss, and fatigue, of whom two presented with flank pain and one with anemia. Their urine chyle tests were confirmed to be positive. Preoperative cystoscopy found that chyluria was from the left side in 3 cases,and from the right side in 2 cases. Their proteinuria ranged from + to ++++. All the cases had been treated with the modified procedure by which lymphatic ligation was performed to hilar vessels and proximalureter via extra-adipose capsule without disconnection of perirenal fat tissues. The operation time, intraoperative blood loss, postoperative intestinal function recovery, catheter time, drainage tube removal time and complications during operation were collected. RESULTS: All the five cases were performed successfully. The operation time ranged from 75 to 170 minutes, mean (126.0±39.6) minutes, with the intraoperative blood loss 20 to 60 mL, mean (38.0±16.4) mL, and the postoperative intestinal function recovery time 1 to 3 days, mean (1.9±0.4) days. The catheter time was 1 to 4 days, mean (2.1±0.3) days and the drainage tube removal time ranged from 3 to 15 days, mean (9.3±1.8) days. Postoperatively lymphorrhagia was found in two cases. No renal vessels injury occurred during operation. Chyluria of all the patients disappeared on the operation day with negative chyluria test after surgery. Furthermore, urine test revealed that proteinuria was totally negative. No recurrence was detected in our patients in the 9 to 31 months' follow-up. CONCLUSION: This modified procedure does not have to disconnect perirenal fat tissues and nephropexy during operation. It was characterized with shorter operation time, definitive effect and fewer complications.

Note: Upgrade of electron cyclotron emission imaging system and preliminary results on HL-2A tokamak.

The electron cyclotron emission imaging system on the HL-2A tokamak has been upgraded to 24 (poloidally) × 16 (radially) channels based on the previous 24 × 8 array. The measurement region can be flexibly shifted due to the independence of the two local oscillator sources, and the field of view can be adjusted easily by changing the position of the zoom lenses. The temporal resolution is about 2.5 µs and the achievable spatial resolution is 1 cm. After laboratory calibration, it was installed on HL-2A tokamak in 2014, and the local 2D mode structures of MHD activities were obtained for the first time.

Calibration of a 32 channel electron cyclotron emission radiometer on the HL-2A tokamak.

A novel 32-channel electron cyclotron emission radiometer has been designed and tested for the measurement of electron temperature profiles on the HL-2A tokamak. This system is based on the intermediate frequency filter detection technique, and has the features of wide working frequency range and high spatial resolution. Two relative calibration methods have been investigated: sweeping the toroidal magnetic field and hopping the output frequency of the local oscillator. Preliminary results show that both methods can ensure reasonable profiles.

Development of frequency modulated continuous wave reflectometer for electron density profile measurement on the HL-2A tokamak.

The frequency modulated continuous wave reflectometer was developed for the first time on the HL-2A tokamak. The system utilizes a voltage controlled oscillator and an active multiplier for broadband coverage and detects as heterodyne mode. Three reflectometers have been installed and operated in extraordinary mode polarization on HL-2A to measure density profiles at low field side, covering the Q-band (33-50 GHz), V-band (50-75 GHz), and W-band (75-110 GHz). For density profile reconstruction from the phase shift of the probing wave, a corrected phase unwrapping method is introduced in this article. The effectiveness of the method is demonstrated. The density profile behavior of a fast plasma event is presented and it demonstrates the capability of the reflectometer. These diagnostics will be contributed to the routine density profile measurements and the plasma physics study on HL-2A.

Development of electron cyclotron emission imaging system on the HL-2A tokamak.

A 2D electron cyclotron emission imaging (ECEI) system has been developed for measurement of electron temperature fluctuations in the HL-2A tokamak. It is comprised of a front-end 24 channel heterodyne imaging array with a tunable RF range spanning 75-110 GHz, and a set of back-end ECEI electronics that together generate 24 × 8 = 192 channel images of the 2nd harmonic X-mode electron cyclotron emission from the HL-2A plasma. The simulated performance of the local oscillator (LO) optics and radio frequency (RF) optics is presented, together with the laboratory characterization results. The Gaussian beams from the LO optics are observed to properly cover the entire detector array. The ECE signals from the plasma are mixed with the LO signal in the array box, then delivered to the electronics system by low-loss microwave cables, and finally to the digitizers. The ECEI system can achieve temporal resolutions of ~µs, and spatial resolutions of 1 cm (radially) and 2 cm (poloidally).

Dynamics of low-intermediate-high-confinement transitions in toroidal plasmas.

The dynamic features of the low-intermediate-high-(L-I-H) confinement transitions on HL-2A tokamak are presented. Here we report the discovery of two types of limit cycles (dubbed type-Y and type-J), which show opposite temporal ordering between the radial electric field and turbulence intensity. In type-Y, which appears first after an L-I transition, the turbulence grows first, followed by the localized electric field. In contrast, the electric field leads type-J. The turbulence-induced zonal flow and pressure-gradient-induced drift play essential roles in the two types of limit cycles, respectively. The condition of transition between types-Y and -J is studied in terms of the normalized radial electric field. An I-H transition is demonstrated to occur only from type-J.