The trajectory of the compact torus(CT)within a tokamak discharge is crucial to fueling.In this study,we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tok...The trajectory of the compact torus(CT)within a tokamak discharge is crucial to fueling.In this study,we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tokamak discharges.This model was used to calculate the trajectory and penetration parameters of CT injections by applying both perpendicular and tangential injection schemes in both HL-2A and ITER tokamaks.For perpendicular injection along the tokamak's major radius direction from the outboard,CTs with the same injection parameters exhibited a 0.08 reduction in relative penetration depth when injected into HL-2A and a 0.13reduction when injected into ITER geometry when considering the vacuum magnetic field region compared with cases where this region was not considered.In addition,we proposed an optimization method for determining the CT's initial injection velocity to accurately calculate the initial injection velocity of CTs for central fueling in tokamaks.Furthermore,this paper discusses schemes for the tangential injection of CT into tokamak discharges.The optimal injection angle and CT magnetic moment direction for injection into both HL-2A and ITER were determined through numerical simulations.Finally,the kinetic energy loss occurring when the CT penetrated the vacuum magnetic field region in ITER was reduced byΔEk=975.08 J by optimizing the injection angle for the CT injected into ITER.These results provide valuable insights for optimizing injection angles in fusion experiments.Our model closely represents actual experimental scenarios and can assist the design of CT parameters.展开更多
Following the reconstruction of the TEXT tokamak at Huazhong University of Science and Technology in China, renamed as J-TEXT, a plethora of experimental and theoretical investigations has been conducted to elucidate ...Following the reconstruction of the TEXT tokamak at Huazhong University of Science and Technology in China, renamed as J-TEXT, a plethora of experimental and theoretical investigations has been conducted to elucidate the intricacies of turbulent transport within the tokamak configuration. These endeavors encompass not only the J-TEXT device's experimental advancements but also delve into critical issues pertinent to the optimization of future fusion devices and reactors. The research includes topics on the suppression of turbulence, flow drive and damping, density limit, non-local transport, intrinsic toroidal flow, turbulence and flow with magnetic islands, turbulent transport in the stochastic layer, and turbulence and zonal flow with energetic particles or helium ash. Several important achievements have been made in the last few years, which will be further elaborated upon in this comprehensive review.展开更多
A dual-route optical emission spectroscopy(D-OES)diagnostic is newly developed to monitor the optical emission from the X-point plasma region on the HL-2 A tokamak.This diagnostic is composed of an imaging system,a be...A dual-route optical emission spectroscopy(D-OES)diagnostic is newly developed to monitor the optical emission from the X-point plasma region on the HL-2 A tokamak.This diagnostic is composed of an imaging system,a beam-splitting system for dual-route measurements,fiber bundles,a spectrometer system,and a control and acquisition system.One route is used to obtain wide-spectral-range spectra,and the other route is used to acquire high-wavelengthresolution line shapes.The spectral resolution of the wide-range spectrometers is 0.8 nm with a coverage of 800 nm(@200-1000 nm).The spectral resolution of the high-resolution spectrometer is 0.01 nm with a coverage of 6 nm(@200-660 nm).The spatial resolution of each route of D-OES is about 4 cm with 11 channels.The temporal resolution is 16 ms at maximum in the single-channel mode.Wide-range spectra(containing Balmer series and a Fulcher band)and highly resolved Ha line shapes are obtained by D-OES in the hydrogen glow discharge in the lab.D-OES measurements are carried out in the high-density deuterium experiments of HL-2A.The electron density n_(e)and deuterium temperature T_(D) in the X-point multifaceted asymmetric radiation from the edge(MARFE)region are derived simultaneously by fitting the measured D_(a) shape.The density n_(e)is observed to increase from~8.7×10^(18)m^(-3)to~7.8×10^(19)m^(-3),and the temperature T_(D)drops from~14.4 eV to~2.3 eV after the onset of MARFE in the discharge#38260.展开更多
Several results based on the Langmuir probes’data on the HL-2A tokamak are presented.The blob structures’radial and poloidal drift velocities,estimated by the gradient of floating potential and by time delay evaluat...Several results based on the Langmuir probes’data on the HL-2A tokamak are presented.The blob structures’radial and poloidal drift velocities,estimated by the gradient of floating potential and by time delay evaluation,are compared in different line-averaged density and electron cyclotron resonance heating conditions.A positive correlation is observed in the comparison between blobs’radial velocity estimated by the two methods mentioned above,regardless of the situation differences mentioned above.Correlation is also observed in the comparison between the blobs’poloidal velocity estimated by the two methods in different situations,while a shift due to the different line-averaged density is observed.These results imply that the radial gradient of floating potential may have some value as a reference during data analysis in low-parameter discharge.展开更多
Rectal neuroendocrine tumors(rNETs)measuring less than 10 mm in diameter are defined as small rNETs.Due to the low risk of distant invasion and metastasis,endoscopic treatments,including modified endoscopic mucosal re...Rectal neuroendocrine tumors(rNETs)measuring less than 10 mm in diameter are defined as small rNETs.Due to the low risk of distant invasion and metastasis,endoscopic treatments,including modified endoscopic mucosal resection,endoscopic submucosal dissection,and other transanal surgical procedures,are effective.This review article proposes a follow-up plan according to the size and histopathology of the tumor after operation.展开更多
A gas puff imaging(GPI) diagnostic has been developed and applied to measure edge plasma turbulence on the HL-2A tokamak.The principle and experimental setup of GPI are described.GPI is applied to investigate blobs in...A gas puff imaging(GPI) diagnostic has been developed and applied to measure edge plasma turbulence on the HL-2A tokamak.The principle and experimental setup of GPI are described.GPI is applied to investigate blobs in the edge and scrape-off layer.Statistical characterizations of GPI line emission intensity are calculated, including the probability density functions(PDFs),skewness, and kurtosis of the intensity, which are found to be consistent with measurements by Langmuir probes.Besides, the track of blob motions is recorded by time sequence of individual frames.The characteristics of the original images and the relatively high-frequency(>10 kHz)/low-frequency(1–10 kHz) component images are illustrated.The observation of the blob’s structures and high-speed motions proves the success and high performance of the GPI diagnostic.展开更多
A CO2 laser-based phase contrast imaging(PCI) diagnostic has been developed on HL-2A tokamak.It can detect line integrated plasma density fluctuations by measuring the phase shift of laser beam after being scattered b...A CO2 laser-based phase contrast imaging(PCI) diagnostic has been developed on HL-2A tokamak.It can detect line integrated plasma density fluctuations by measuring the phase shift of laser beam after being scattered by the bulk plasma.The diagnosed radial region ranges from ρ≡r/a =0.625 to 0.7.32-channel HgCdTe detectors with alternative-current biased amplifiers are arranged in line at the imaging plane of the optical path.This PCI is able to diagnose density fluctuations with wavenumbers ranging from 2 to 15 cm-1 and the time resolution is better than 2 μs.The first experimental data were achieved in 2018 spring campaign of HL-2A tokamak.High performance is confirmed in different discharging configurations and makes it a keen tool in broadband turbulence investigations.展开更多
A newly developed Doppler coherence imaging spectroscopy(CIS)technique has been implemented in the HL-2 A tokamak for carbon impurity emissivity and flow measurement.In CIS diagnostics,the emissivity and flow profiles...A newly developed Doppler coherence imaging spectroscopy(CIS)technique has been implemented in the HL-2 A tokamak for carbon impurity emissivity and flow measurement.In CIS diagnostics,the emissivity and flow profiles inside the plasma are measured by a camera from the line-integrated emissivity and line-averaged flow,respectively.A standard inference method,called tomographic inversion,is necessary.Such an inversion is relatively challenging due to the ill-conditioned nature.In this article,we report the recent application and comparison of two different tomography algorithms,Gaussian process tomography and Tikhonov tomography,on light intensity measured by CIS,including feasibility and benchmark studies.Finally,the tomographic results for real measurement data in HL-2A are presented.展开更多
BACKGROUND Liver cirrhosis is the main cause of portal hypertension.The leading cause of death in patients with liver cirrhosis is its most common complication,esophageal variceal bleeding(EVB).Endoscopic variceal lig...BACKGROUND Liver cirrhosis is the main cause of portal hypertension.The leading cause of death in patients with liver cirrhosis is its most common complication,esophageal variceal bleeding(EVB).Endoscopic variceal ligation(EVL)is recommended by many guidelines to treat EVB and prevent rebleeding;however,esophageal ulcers occur after treatment.Delayed healing of ulcers and unhealed ulcers lead to high rebleeding and mortality rates.Thus,the prevention of early postoperative rebleeding is of great significance in improving the quality of life and prognosis of patients.AIM To evaluate the efficacy of aluminum phosphate gel(APG)plus a proton pump inhibitor(PPI)in the prevention of early rebleeding after EVL in patients with EVB.METHODS The medical records of 792 patients who were diagnosed with EVB and in whom bleeding was successfully stopped by EVL at Shenzhen People’s Hospital,Guangdong Province,China from January 2015 to December 2020 were collected.According to the study inclusion and exclusion criteria,401 cases were included in a PPI-monotherapy group(PPI group),and 377 cases were included in a PPI and APG combination therapy(PPI+APG)group.We compared the incidence rates of early rebleeding and other complications within 6 wk after treatment between the two groups.The two-sample t-test,Wilcoxon rank-sum test,and chisquared test were adopted for statistical analyses.RESULTS No significant differences in age,sex,model for end-stage liver disease score,coagulation function,serum albumin level,or hemoglobin level were found between the two groups.The incidence of early rebleeding in the PPI+APG group(9/337;2.39%)was significantly lower than that in the PPI group(30/401;7.48%)(P=0.001).Causes of early rebleeding in the PPI group were esophageal ulcer(3.99%,16/401)and esophageal varices(3.49%,14/401),while those in the PPI+APG group were also esophageal ulcers(5/377;1.33%)and esophageal varices(4/377;1.06%);such causes were significantly less frequent in the PPI+APG group than in the PPI group(P=0.022 and 0.024,respectively).The early mortality rate within 6 wk in both groups was 0%,which was correlated with the timely rehospitalization of all patients with rebleeding and the conduct of emergency endoscopic therapy.The incidence of adverse events other than early bleeding in the PPI+APG group(28/377;7.43%)was significantly lower than that in the PPI group(63/401;15.71%)(P<0.001).The incidence of chest pain in the PPI+APG group(9/377;2.39%)was significantly lower than that in the PPI group(56/401;13.97%)(P<0.001).The incidence of constipation in the PPI+APG group(16/377;4.24%)was significantly higher than that in the PPI group(3/401;0.75%)(P=0.002)but constipation was relieved after patients drank more water or took lactulose.In the PPI and PPI+APG groups,the incidence rates of spontaneous peritonitis within 6 wk after discharge were 0.50%(2/401)and 0.53%(2/377),respectively,and those of hepatic encephalopathy were 0.50%(2/401)and 0.27%(1/377),respectively,presenting no significant difference(P>0.999).CONCLUSION PPI+APG combination therapy significantly reduces the incidence of early rebleeding and chest pain in patients with EVB after EVL.展开更多
The global rate of type 2 diabetes mellitus (T2DM) in youth has increased dramatically in the last 30 years. This increase mirrors the global epidemic of childhood obesity. Studies show that, compared to adults who de...The global rate of type 2 diabetes mellitus (T2DM) in youth has increased dramatically in the last 30 years. This increase mirrors the global epidemic of childhood obesity. Studies show that, compared to adults who develop T2DM, youth with T2DM ultimately suffer from more harmful symptoms. The prevalence of T2DM and obesity in youth signals a significant public health issue that financially burdens governments, families, and individuals. Since evidence suggests that T2DM in youth is different from both type 1 and type 2 diabetes in adults, researchers and clinicians face many difficulties in developing new treatments. Most treatment efforts have relied on drugs;however, recent studies suggest that non-drug therapy also effectively reduces obesity and diabetic symptoms. Healthier eating, increased physical exercise, and positive mental health, are often underappreciated factors towards managing obesity. Yet these lifestyle changes empower both young and older patients to independently fight diseases and attain better health. To manage the global health risk of obesity, further research addressing the prevention and nondrug early intervention of T2DM and obesity in youth is urgently needed. The present review focuses on the latest updates in the field.展开更多
Field computation, an emerging computation technique, has inspired passion of intelligence science research. A novel field computation model based on the magnetic field theory is constructed. The proposed magnetic fie...Field computation, an emerging computation technique, has inspired passion of intelligence science research. A novel field computation model based on the magnetic field theory is constructed. The proposed magnetic field computation （MFC） model consists of a field simulator, a non-derivative optimization algo- rithm and an auxiliary data processing unit. The mathematical model is deduced and proved that the MFC model is equivalent to a quadratic discriminant function. Furthermore, the finite element prototype is derived, and the simulator is developed, combining with particle swarm optimizer for the field configuration. Two benchmark classification experiments are studied in the numerical experiment, and one notable advantage is demonstrated that less training samples are required and a better generalization can be achieved.展开更多
Effect of edge turbulent transport on scrape-off layer(SOL)width has been investigated in Ohmically heated L-mode plasma under limiter configurations on HL-2A tokamak.It has been found that SOL width is doubled when p...Effect of edge turbulent transport on scrape-off layer(SOL)width has been investigated in Ohmically heated L-mode plasma under limiter configurations on HL-2A tokamak.It has been found that SOL width is doubled when plasma current decreases about 20%.With larger plasma current,E×B shear is stronger and has greater suppression effect on edge turbulent transport.SOL width is larger when power of relative density fluctuation level in the edge region is larger.It is concluded that edge turbulent transport plays a significant role on SOL width.These experimental findings may provide a better understanding and controlling of power exhaust for present and future fusion devices.展开更多
The effect of resonant magnetic perturbation(RMP) on boundary turbulence and transport in J-TEXT plasma is experimentally investigated.Edge plasma fluctuations in discharges with and without the(m/n=3/1) RMP currents ...The effect of resonant magnetic perturbation(RMP) on boundary turbulence and transport in J-TEXT plasma is experimentally investigated.Edge plasma fluctuations in discharges with and without the(m/n=3/1) RMP currents are diagnosed by using Langmuir probe arrays.It was found that fluctuations in the edge and scrape-off layer(SOL) regions decrease with the application of a 6 kA RMP.The broadband turbulence at the radial location of ρ~0.9 which has a characteristic frequency of 40-150 kHz was strongly suppressed when applying RMP,as was the radial turbulent particle flux and blob transport in the near-SOL region.These experimental findings make RMP a promising method of suppressing and controlling turbulence and particle transport in a plasma boundary.展开更多
Developing advanced magnetic divertor configurations to address the coupling of heat and particle exhaust with impurity control is one of the major challenges currently constraining the further development of fusion r...Developing advanced magnetic divertor configurations to address the coupling of heat and particle exhaust with impurity control is one of the major challenges currently constraining the further development of fusion research.It has therefore become the focus of extensive attention in recent years.In J-TEXT,several new divertor configurations,including the high-field-side single-null poloidal divertor and the island divertor,as well as their associated fundamental edge divertor plasma physics,have recently been investigated.The purpose of this paper is to briefly summarize the latest progress and achievements in this relevant research field on J-TEXT from the past few years.展开更多
High-density experiments in the high-field-side mid-plane single-null divertor configuration have been performed for the first time on J-TEXT.The experiments show an increase in the highest central channel line-averag...High-density experiments in the high-field-side mid-plane single-null divertor configuration have been performed for the first time on J-TEXT.The experiments show an increase in the highest central channel line-averaged density from 2.73×10^(19)m^(-3) to 6.49×10^(19)m^(-3),while the X-point moves away from the target by increasing the divertor coil current.The corresponding Greenwald fraction rises from 0.50 to 0.79.For the impurity transport,the density normalized radiation intensity(absolute extreme ultraviolet and soft x-ray)of the central channel density decreased significantly(>50%)with an increase in the plasma density.To better understand the underlying physics mechanisms,the 3 D edge Monte Carlo code coupled with EIRENE(EMC3-EIRENE)has been implemented for the first time on J-TEXT.The simulation results show good agreement with the experimental findings.As the X-point moves away from the target,the divertor power decay length drops and the scrape-off layer impurity screening effect is enhanced.展开更多
Vanadium redox flow batteries(VRFBs)are widely applied in energy storage systems(e.g.,wind energy,solar energy),while the poor activity of commonly used carbon-based electrode limits their large-scale application.In t...Vanadium redox flow batteries(VRFBs)are widely applied in energy storage systems(e.g.,wind energy,solar energy),while the poor activity of commonly used carbon-based electrode limits their large-scale application.In this study,the graphene modified carbon felt(G/CF)with a large area of 20 cm×20 cm has been successfully prepared by a chemical vapor deposition(CVD)strategy,achieving outstanding electrocatalytic redox reversibility of the VRFBs.The decorating graphene can provide abundant active sites for the vanadium redox reactions.Compared with the pristine carbon felt(CF)electrode,the G/CF composite electrode possesses more defective sites on surface,which enhances activity toward VO^(2+)/VO^(2+)couple and electrochemical performances.For instance,such G/CF electrode delivered remarkable voltage efficiency(VE)of 88.4%and energy efficiency(EE)of 86.4%at 100 mA·cm^(-2),much higher than CF electrode by 2.1%and 3.78%,respectively.The long-term cycling stability of G/CF electrode was further investigated and a high retention value of 47.6%can be achieved over 600 cycles.It is demonstrated that this work develops a promising and effective strategy to synthesize the large size of carbon electrode with high performances for the next-generation VRFBs.展开更多
Free-surface flows, especially those associated with fluid-structure interactions(FSIs), pose challenging problems in numerical simulations. The authors of this work recently developed a smoothed particle element meth...Free-surface flows, especially those associated with fluid-structure interactions(FSIs), pose challenging problems in numerical simulations. The authors of this work recently developed a smoothed particle element method(SPEM) to simulate FSIs. In this method, both the fluid and solid regions are initially modeled using a smoothed finite element method(S-FEM) in a Lagrangian frame, whereas the fluid regions undergoing large deformations are adaptively converted into particles and modeled with an improved smoothed particle hydrodynamics(SPH) method. This approach greatly improves computational accuracy and efficiency because of the advantages of the S-FEM in efficiently treating solid/fluid regions showing small deformations and the SPH method in effectively modeling moving interfaces. In this work, we further enhance the efficiency of the SPEM while effectively capturing local fluid information by introducing a multi-resolution technique to the SPEM and developing an effective approach to treat multi-resolution element-particle interfaces. Various numerical examples demonstrate that the multiresolution SPEM can significantly reduce the computational cost relative to the original version with a constant resolution.Moreover, the novel approach is effective in modeling various incompressible flow problems involving FSIs.展开更多
Background： The treatment of the condylar fractures is difficult. Factors that result in the fractures are complex. The objective of this morphometric study was to investigate the relationship between condylar fractu...Background： The treatment of the condylar fractures is difficult. Factors that result in the fractures are complex. The objective of this morphometric study was to investigate the relationship between condylar fracture patterns and condylar morphological characteristics. Methods： We conducted a retrospective analysis of 107 patients admitted to the West China Hospital of Stomatology for bilateral condylar fractures caused by parasymphyseal impact. The patients were divided into five groups according to the type of condylar fracture. Ten parameters were evaluated on three-dimensional （3D） reconstruction mandible models through the Mimics 16.0 （Materialize Leuven, Belgium） anthropometry toolkit. Each parameter of the 3D models was analyzed using multivariate analysis. Multinomial logistic regression analyses were used to examine the relationships between the five groups. Results： The results showed that the differences of condylar head width （M 1 ）, condylar neck width （M3）, the ratio of condylar head width to condylar anteroposterior diameter （M1/M2）, the ratio of condylar head width to condylar neck width （M1/M3）, the ratio of condylar height to ramus height （M8/M7）, and mandibular angle （M10） were statistically significant （p 〈 0.05）. Type A condylar head fractures were positively associated with M1 （compared to Type B： OR ：1.627, 95% CI： 1.123, 2.359; compared to Type C： OR = 1.705, 95% CI： 1.170, 2.484） and M1/M2 （compared to Type B： OR = 1.034, 95% CI： 0.879, 2.484）. Type B condylar head fractures were negatively associated with M l 0 （compared to Type C： OR = 0.909, 95% CI： 0.821, 1.007）. Condylar neck fractures were negatively associated with M3 （compared to condylar head： OR = 0.382, CI： 0.203, 0.720 ; compared to condylar base： OR = 0.436, 95% CI： 0.218, 0.874）, and positively associated with M 1/M3 （compared to condylar head： OR = 1.229, 95% CI： 1.063, 1.420 compared to condylar base： OR = 1.223, 95% CI： 1.034, 1.447）. Condylar base fractures were positively associated with M10 （OR = 1.095, 95% CI： 1.008, 1.189） and negatively associated with M8/M7 （OR = 0.855, 95% CI： 0.763, 0.959） as compared with condylar head fractures. Conclusions： Condylar fracture pattern is associated with the anatomical features of the condyles when a fracture occurs from parasymphyseal impact.展开更多
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2022YFE03100004 and 2022YFE03060003)National Natural Science Foundation of China(Nos.12375226,12175227 and 11875255)the China Postdoctoral Science Foundation(No.2022M723066).
文摘The trajectory of the compact torus(CT)within a tokamak discharge is crucial to fueling.In this study,we developed a penetration model with a vacuum magnetic field region to accurately determine CT trajectories in tokamak discharges.This model was used to calculate the trajectory and penetration parameters of CT injections by applying both perpendicular and tangential injection schemes in both HL-2A and ITER tokamaks.For perpendicular injection along the tokamak's major radius direction from the outboard,CTs with the same injection parameters exhibited a 0.08 reduction in relative penetration depth when injected into HL-2A and a 0.13reduction when injected into ITER geometry when considering the vacuum magnetic field region compared with cases where this region was not considered.In addition,we proposed an optimization method for determining the CT's initial injection velocity to accurately calculate the initial injection velocity of CTs for central fueling in tokamaks.Furthermore,this paper discusses schemes for the tangential injection of CT into tokamak discharges.The optimal injection angle and CT magnetic moment direction for injection into both HL-2A and ITER were determined through numerical simulations.Finally,the kinetic energy loss occurring when the CT penetrated the vacuum magnetic field region in ITER was reduced byΔEk=975.08 J by optimizing the injection angle for the CT injected into ITER.These results provide valuable insights for optimizing injection angles in fusion experiments.Our model closely represents actual experimental scenarios and can assist the design of CT parameters.
基金supported by the National Key R&D Program of China (Nos. 2022YFE03100004, 2017YFE0302000, and 2017YFE0301100)National Natural Science Foundation of China (Nos. 12275097, 12275096, 11875292, 11675059, 11905079, 11305071, and 51821005)+5 种基金the Ministry of Science and Technology of China (No. 2013GB112002)the Project of Science and Technology Department of Sichuan Province (No. 2022NSFSC1791)the Natural Science Foundation of Anhui Province (No. 2208085J39)the Fundamental Research Funds for the Central Universities, HUST: (Nos. 2019kfy XMBZ034 and 2021XXJS007)the Initiative Postdocs Supporting Program of China (No. BX20180105)the US Department of Energy, Office of Science, Office of Fusion Energy Sciences (Nos. DEFG02-04ER54738 and DE-SC-0020287)。
文摘Following the reconstruction of the TEXT tokamak at Huazhong University of Science and Technology in China, renamed as J-TEXT, a plethora of experimental and theoretical investigations has been conducted to elucidate the intricacies of turbulent transport within the tokamak configuration. These endeavors encompass not only the J-TEXT device's experimental advancements but also delve into critical issues pertinent to the optimization of future fusion devices and reactors. The research includes topics on the suppression of turbulence, flow drive and damping, density limit, non-local transport, intrinsic toroidal flow, turbulence and flow with magnetic islands, turbulent transport in the stochastic layer, and turbulence and zonal flow with energetic particles or helium ash. Several important achievements have been made in the last few years, which will be further elaborated upon in this comprehensive review.
基金supported by the National MCF Energy R&D Program of China(Nos.2018YFE0301102,2022YFE03100004 and 2018YFE 0303102)National Natural Science Foundation of China(Nos.12375210 and 12305238)the Sichuan Natural Science Foundation(Nos.2022NSFSC1791,2022JDRC0014 and 2022TFQCCXTD)。
文摘A dual-route optical emission spectroscopy(D-OES)diagnostic is newly developed to monitor the optical emission from the X-point plasma region on the HL-2 A tokamak.This diagnostic is composed of an imaging system,a beam-splitting system for dual-route measurements,fiber bundles,a spectrometer system,and a control and acquisition system.One route is used to obtain wide-spectral-range spectra,and the other route is used to acquire high-wavelengthresolution line shapes.The spectral resolution of the wide-range spectrometers is 0.8 nm with a coverage of 800 nm(@200-1000 nm).The spectral resolution of the high-resolution spectrometer is 0.01 nm with a coverage of 6 nm(@200-660 nm).The spatial resolution of each route of D-OES is about 4 cm with 11 channels.The temporal resolution is 16 ms at maximum in the single-channel mode.Wide-range spectra(containing Balmer series and a Fulcher band)and highly resolved Ha line shapes are obtained by D-OES in the hydrogen glow discharge in the lab.D-OES measurements are carried out in the high-density deuterium experiments of HL-2A.The electron density n_(e)and deuterium temperature T_(D) in the X-point multifaceted asymmetric radiation from the edge(MARFE)region are derived simultaneously by fitting the measured D_(a) shape.The density n_(e)is observed to increase from~8.7×10^(18)m^(-3)to~7.8×10^(19)m^(-3),and the temperature T_(D)drops from~14.4 eV to~2.3 eV after the onset of MARFE in the discharge#38260.
基金supported by the National Key Research and Development Program of China(Nos.2017YFE0300500,2017YFE0300501)No.2018YFE0309100National Natural Science Foundation of China(Nos.11705052,11875124,11905050,11875020 and U1867222)。
文摘Several results based on the Langmuir probes’data on the HL-2A tokamak are presented.The blob structures’radial and poloidal drift velocities,estimated by the gradient of floating potential and by time delay evaluation,are compared in different line-averaged density and electron cyclotron resonance heating conditions.A positive correlation is observed in the comparison between blobs’radial velocity estimated by the two methods mentioned above,regardless of the situation differences mentioned above.Correlation is also observed in the comparison between the blobs’poloidal velocity estimated by the two methods in different situations,while a shift due to the different line-averaged density is observed.These results imply that the radial gradient of floating potential may have some value as a reference during data analysis in low-parameter discharge.
文摘Rectal neuroendocrine tumors(rNETs)measuring less than 10 mm in diameter are defined as small rNETs.Due to the low risk of distant invasion and metastasis,endoscopic treatments,including modified endoscopic mucosal resection,endoscopic submucosal dissection,and other transanal surgical procedures,are effective.This review article proposes a follow-up plan according to the size and histopathology of the tumor after operation.
基金supported by the National Key Research and Development Program of China (No.2017YFE0300405)National Natural Science Foundation of China (Nos.11575055, 11705052, 11875124, 11475058, and 11475056)+1 种基金the National Key Research and Development Program of China (Nos.2017YFE0301201, 2018YFE0303102, 2018YFE0309103)the Chinese National Fusion Project for ITER (No.2015GB104000)
文摘A gas puff imaging(GPI) diagnostic has been developed and applied to measure edge plasma turbulence on the HL-2A tokamak.The principle and experimental setup of GPI are described.GPI is applied to investigate blobs in the edge and scrape-off layer.Statistical characterizations of GPI line emission intensity are calculated, including the probability density functions(PDFs),skewness, and kurtosis of the intensity, which are found to be consistent with measurements by Langmuir probes.Besides, the track of blob motions is recorded by time sequence of individual frames.The characteristics of the original images and the relatively high-frequency(>10 kHz)/low-frequency(1–10 kHz) component images are illustrated.The observation of the blob’s structures and high-speed motions proves the success and high performance of the GPI diagnostic.
基金supported by the National Key Research and Development Program of China (No.2017YFE0300405)National Natural Science Foundation of China (Nos.11875124, 11705052, 11575055 and 11611130164)the National Magnetic Confinement Fusion Science Program of China (No.2015GB120002)
文摘A CO2 laser-based phase contrast imaging(PCI) diagnostic has been developed on HL-2A tokamak.It can detect line integrated plasma density fluctuations by measuring the phase shift of laser beam after being scattered by the bulk plasma.The diagnosed radial region ranges from ρ≡r/a =0.625 to 0.7.32-channel HgCdTe detectors with alternative-current biased amplifiers are arranged in line at the imaging plane of the optical path.This PCI is able to diagnose density fluctuations with wavenumbers ranging from 2 to 15 cm-1 and the time resolution is better than 2 μs.The first experimental data were achieved in 2018 spring campaign of HL-2A tokamak.High performance is confirmed in different discharging configurations and makes it a keen tool in broadband turbulence investigations.
文摘A newly developed Doppler coherence imaging spectroscopy(CIS)technique has been implemented in the HL-2 A tokamak for carbon impurity emissivity and flow measurement.In CIS diagnostics,the emissivity and flow profiles inside the plasma are measured by a camera from the line-integrated emissivity and line-averaged flow,respectively.A standard inference method,called tomographic inversion,is necessary.Such an inversion is relatively challenging due to the ill-conditioned nature.In this article,we report the recent application and comparison of two different tomography algorithms,Gaussian process tomography and Tikhonov tomography,on light intensity measured by CIS,including feasibility and benchmark studies.Finally,the tomographic results for real measurement data in HL-2A are presented.
基金Natural Science Foundation of Guangdong Province of China,No.2018A0303130278.
文摘BACKGROUND Liver cirrhosis is the main cause of portal hypertension.The leading cause of death in patients with liver cirrhosis is its most common complication,esophageal variceal bleeding(EVB).Endoscopic variceal ligation(EVL)is recommended by many guidelines to treat EVB and prevent rebleeding;however,esophageal ulcers occur after treatment.Delayed healing of ulcers and unhealed ulcers lead to high rebleeding and mortality rates.Thus,the prevention of early postoperative rebleeding is of great significance in improving the quality of life and prognosis of patients.AIM To evaluate the efficacy of aluminum phosphate gel(APG)plus a proton pump inhibitor(PPI)in the prevention of early rebleeding after EVL in patients with EVB.METHODS The medical records of 792 patients who were diagnosed with EVB and in whom bleeding was successfully stopped by EVL at Shenzhen People’s Hospital,Guangdong Province,China from January 2015 to December 2020 were collected.According to the study inclusion and exclusion criteria,401 cases were included in a PPI-monotherapy group(PPI group),and 377 cases were included in a PPI and APG combination therapy(PPI+APG)group.We compared the incidence rates of early rebleeding and other complications within 6 wk after treatment between the two groups.The two-sample t-test,Wilcoxon rank-sum test,and chisquared test were adopted for statistical analyses.RESULTS No significant differences in age,sex,model for end-stage liver disease score,coagulation function,serum albumin level,or hemoglobin level were found between the two groups.The incidence of early rebleeding in the PPI+APG group(9/337;2.39%)was significantly lower than that in the PPI group(30/401;7.48%)(P=0.001).Causes of early rebleeding in the PPI group were esophageal ulcer(3.99%,16/401)and esophageal varices(3.49%,14/401),while those in the PPI+APG group were also esophageal ulcers(5/377;1.33%)and esophageal varices(4/377;1.06%);such causes were significantly less frequent in the PPI+APG group than in the PPI group(P=0.022 and 0.024,respectively).The early mortality rate within 6 wk in both groups was 0%,which was correlated with the timely rehospitalization of all patients with rebleeding and the conduct of emergency endoscopic therapy.The incidence of adverse events other than early bleeding in the PPI+APG group(28/377;7.43%)was significantly lower than that in the PPI group(63/401;15.71%)(P<0.001).The incidence of chest pain in the PPI+APG group(9/377;2.39%)was significantly lower than that in the PPI group(56/401;13.97%)(P<0.001).The incidence of constipation in the PPI+APG group(16/377;4.24%)was significantly higher than that in the PPI group(3/401;0.75%)(P=0.002)but constipation was relieved after patients drank more water or took lactulose.In the PPI and PPI+APG groups,the incidence rates of spontaneous peritonitis within 6 wk after discharge were 0.50%(2/401)and 0.53%(2/377),respectively,and those of hepatic encephalopathy were 0.50%(2/401)and 0.27%(1/377),respectively,presenting no significant difference(P>0.999).CONCLUSION PPI+APG combination therapy significantly reduces the incidence of early rebleeding and chest pain in patients with EVB after EVL.
文摘The global rate of type 2 diabetes mellitus (T2DM) in youth has increased dramatically in the last 30 years. This increase mirrors the global epidemic of childhood obesity. Studies show that, compared to adults who develop T2DM, youth with T2DM ultimately suffer from more harmful symptoms. The prevalence of T2DM and obesity in youth signals a significant public health issue that financially burdens governments, families, and individuals. Since evidence suggests that T2DM in youth is different from both type 1 and type 2 diabetes in adults, researchers and clinicians face many difficulties in developing new treatments. Most treatment efforts have relied on drugs;however, recent studies suggest that non-drug therapy also effectively reduces obesity and diabetic symptoms. Healthier eating, increased physical exercise, and positive mental health, are often underappreciated factors towards managing obesity. Yet these lifestyle changes empower both young and older patients to independently fight diseases and attain better health. To manage the global health risk of obesity, further research addressing the prevention and nondrug early intervention of T2DM and obesity in youth is urgently needed. The present review focuses on the latest updates in the field.
基金supported by the National Natural Science Foundation of China(60903005)the National Basic Research Program of China(973 Program)(2012CB821206)
文摘Field computation, an emerging computation technique, has inspired passion of intelligence science research. A novel field computation model based on the magnetic field theory is constructed. The proposed magnetic field computation （MFC） model consists of a field simulator, a non-derivative optimization algo- rithm and an auxiliary data processing unit. The mathematical model is deduced and proved that the MFC model is equivalent to a quadratic discriminant function. Furthermore, the finite element prototype is derived, and the simulator is developed, combining with particle swarm optimizer for the field configuration. Two benchmark classification experiments are studied in the numerical experiment, and one notable advantage is demonstrated that less training samples are required and a better generalization can be achieved.
基金by National Natural Science Foundation of China(Nos.11875124,U1867222,11575055,11705052,11875020 and 11705151)National Key Research and Development Program of China(Nos.2018YFE0309103,2018YFE0303102,2017YFE0300405 and 2017YFE0301203).
文摘Effect of edge turbulent transport on scrape-off layer(SOL)width has been investigated in Ohmically heated L-mode plasma under limiter configurations on HL-2A tokamak.It has been found that SOL width is doubled when plasma current decreases about 20%.With larger plasma current,E×B shear is stronger and has greater suppression effect on edge turbulent transport.SOL width is larger when power of relative density fluctuation level in the edge region is larger.It is concluded that edge turbulent transport plays a significant role on SOL width.These experimental findings may provide a better understanding and controlling of power exhaust for present and future fusion devices.
基金supported by the National Key Research & Development Programme of China (No. 2018YFE0309100, 2017YFE0301201)National Natural Science Foundation of China (Nos. 11875124, U1867222, 11575055, 11705052 & 11705151)the National Magnetic Confinement Fusion Science Programme of China (Nos. 2015GB120002, 2015GB11101 & 2015GB104000)
文摘The effect of resonant magnetic perturbation(RMP) on boundary turbulence and transport in J-TEXT plasma is experimentally investigated.Edge plasma fluctuations in discharges with and without the(m/n=3/1) RMP currents are diagnosed by using Langmuir probe arrays.It was found that fluctuations in the edge and scrape-off layer(SOL) regions decrease with the application of a 6 kA RMP.The broadband turbulence at the radial location of ρ~0.9 which has a characteristic frequency of 40-150 kHz was strongly suppressed when applying RMP,as was the radial turbulent particle flux and blob transport in the near-SOL region.These experimental findings make RMP a promising method of suppressing and controlling turbulence and particle transport in a plasma boundary.
基金supported by the National MCF Energy R&D Program of China(Nos.2018YFE0309100 and 2018YFE0310300)the National Key R&D Program of China(No.2017YFE0302000)National Natural Science Foundation of China(No.51821005)
文摘Developing advanced magnetic divertor configurations to address the coupling of heat and particle exhaust with impurity control is one of the major challenges currently constraining the further development of fusion research.It has therefore become the focus of extensive attention in recent years.In J-TEXT,several new divertor configurations,including the high-field-side single-null poloidal divertor and the island divertor,as well as their associated fundamental edge divertor plasma physics,have recently been investigated.The purpose of this paper is to briefly summarize the latest progress and achievements in this relevant research field on J-TEXT from the past few years.
基金supported by the National Magnetic Confinement Fusion Energy R&D Program of China (Nos.2018YFE0301104 and 2018YFE0309100)National Natural Science Foundation of China (No. 51821005).
文摘High-density experiments in the high-field-side mid-plane single-null divertor configuration have been performed for the first time on J-TEXT.The experiments show an increase in the highest central channel line-averaged density from 2.73×10^(19)m^(-3) to 6.49×10^(19)m^(-3),while the X-point moves away from the target by increasing the divertor coil current.The corresponding Greenwald fraction rises from 0.50 to 0.79.For the impurity transport,the density normalized radiation intensity(absolute extreme ultraviolet and soft x-ray)of the central channel density decreased significantly(>50%)with an increase in the plasma density.To better understand the underlying physics mechanisms,the 3 D edge Monte Carlo code coupled with EIRENE(EMC3-EIRENE)has been implemented for the first time on J-TEXT.The simulation results show good agreement with the experimental findings.As the X-point moves away from the target,the divertor power decay length drops and the scrape-off layer impurity screening effect is enhanced.
基金the financial support from the 100 Talented Team of Hunan Province(XiangZu[2016]91)the“Huxiang high-level talents”program(Nos.2018RS3077,2019RS1007,and 2019RS1046)+1 种基金the National Natural Science Foundation of China(No.52002405)the Open Fund of National Engineering Laboratory of Highway Maintenance Technology(Changsha University of Science&Technology)(No.kfj170105).
文摘Vanadium redox flow batteries(VRFBs)are widely applied in energy storage systems(e.g.,wind energy,solar energy),while the poor activity of commonly used carbon-based electrode limits their large-scale application.In this study,the graphene modified carbon felt(G/CF)with a large area of 20 cm×20 cm has been successfully prepared by a chemical vapor deposition(CVD)strategy,achieving outstanding electrocatalytic redox reversibility of the VRFBs.The decorating graphene can provide abundant active sites for the vanadium redox reactions.Compared with the pristine carbon felt(CF)electrode,the G/CF composite electrode possesses more defective sites on surface,which enhances activity toward VO^(2+)/VO^(2+)couple and electrochemical performances.For instance,such G/CF electrode delivered remarkable voltage efficiency(VE)of 88.4%and energy efficiency(EE)of 86.4%at 100 mA·cm^(-2),much higher than CF electrode by 2.1%and 3.78%,respectively.The long-term cycling stability of G/CF electrode was further investigated and a high retention value of 47.6%can be achieved over 600 cycles.It is demonstrated that this work develops a promising and effective strategy to synthesize the large size of carbon electrode with high performances for the next-generation VRFBs.
基金supported by the National Numerical Wind Tunnel Project (Grant No. NNW2019ZT2-B02)the National Natural Science Foundation of China (Grant Nos. 12032002,51779003,and 11902005)the SinoGerman Mobility Programme (Grant No. M-0210)。
文摘Free-surface flows, especially those associated with fluid-structure interactions(FSIs), pose challenging problems in numerical simulations. The authors of this work recently developed a smoothed particle element method(SPEM) to simulate FSIs. In this method, both the fluid and solid regions are initially modeled using a smoothed finite element method(S-FEM) in a Lagrangian frame, whereas the fluid regions undergoing large deformations are adaptively converted into particles and modeled with an improved smoothed particle hydrodynamics(SPH) method. This approach greatly improves computational accuracy and efficiency because of the advantages of the S-FEM in efficiently treating solid/fluid regions showing small deformations and the SPH method in effectively modeling moving interfaces. In this work, we further enhance the efficiency of the SPEM while effectively capturing local fluid information by introducing a multi-resolution technique to the SPEM and developing an effective approach to treat multi-resolution element-particle interfaces. Various numerical examples demonstrate that the multiresolution SPEM can significantly reduce the computational cost relative to the original version with a constant resolution.Moreover, the novel approach is effective in modeling various incompressible flow problems involving FSIs.
文摘Background： The treatment of the condylar fractures is difficult. Factors that result in the fractures are complex. The objective of this morphometric study was to investigate the relationship between condylar fracture patterns and condylar morphological characteristics. Methods： We conducted a retrospective analysis of 107 patients admitted to the West China Hospital of Stomatology for bilateral condylar fractures caused by parasymphyseal impact. The patients were divided into five groups according to the type of condylar fracture. Ten parameters were evaluated on three-dimensional （3D） reconstruction mandible models through the Mimics 16.0 （Materialize Leuven, Belgium） anthropometry toolkit. Each parameter of the 3D models was analyzed using multivariate analysis. Multinomial logistic regression analyses were used to examine the relationships between the five groups. Results： The results showed that the differences of condylar head width （M 1 ）, condylar neck width （M3）, the ratio of condylar head width to condylar anteroposterior diameter （M1/M2）, the ratio of condylar head width to condylar neck width （M1/M3）, the ratio of condylar height to ramus height （M8/M7）, and mandibular angle （M10） were statistically significant （p 〈 0.05）. Type A condylar head fractures were positively associated with M1 （compared to Type B： OR ：1.627, 95% CI： 1.123, 2.359; compared to Type C： OR = 1.705, 95% CI： 1.170, 2.484） and M1/M2 （compared to Type B： OR = 1.034, 95% CI： 0.879, 2.484）. Type B condylar head fractures were negatively associated with M l 0 （compared to Type C： OR = 0.909, 95% CI： 0.821, 1.007）. Condylar neck fractures were negatively associated with M3 （compared to condylar head： OR = 0.382, CI： 0.203, 0.720 ; compared to condylar base： OR = 0.436, 95% CI： 0.218, 0.874）, and positively associated with M 1/M3 （compared to condylar head： OR = 1.229, 95% CI： 1.063, 1.420 compared to condylar base： OR = 1.223, 95% CI： 1.034, 1.447）. Condylar base fractures were positively associated with M10 （OR = 1.095, 95% CI： 1.008, 1.189） and negatively associated with M8/M7 （OR = 0.855, 95% CI： 0.763, 0.959） as compared with condylar head fractures. Conclusions： Condylar fracture pattern is associated with the anatomical features of the condyles when a fracture occurs from parasymphyseal impact.
