Characteristics of the SOL ion-to-electron temperature ratio on the J-TEXT tokamak with different plasma configurations

Accurate measurement of the average plasma parameters in the edge region,including the temperature and density of electrons and ions,is critical for understanding the characteristics of the scrape-off layer(SOL) and divertor plasma transport in magnetically confined fusion research.On the J-TEXT tokamak,a multi-channel retarding field analyzer(RFA) probe has been developed to study average plasma parameters in the edge region under various poloidal divertor and island divertor configurations.The edge radial profile of the ion-to-electron temperature ratio,τ_(i/e),has been determined,which gradually decreases as the SOL ion self-collisionality,v_(SOL)*,increases.This is broadly consistent with what has been observed previously from various tokamak experiments.However,the comparison of experimental results under different configurations shows that in the poloidal divertor configuration,even under the same v_(SOL)*,τ_(i/e) in the SOL region becomes smaller as the distance from the X-point to the target plate increases.In the island divertor configuration,τ_(i/e) near the O-point is higher than that near the X-point at the same v_(SOL)*,and both are higher than those in the limiter configuration.These results suggest that the magnetic configuration plays a critical role in the energy distributions between electrons and ions at the plasma boundary.

Surface Patterning of Metal Zinc Electrode with an In‑Region Zincophilic Interface for High‑Rate and Long‑Cycle‑Life Zinc Metal Anode

The undesirable dendrite growth induced by non-planar zinc(Zn)deposition and low Coulombic efficiency resulting from severe side reactions have been long-standing challenges for metallic Zn anodes and substantially impede the practical application of rechargeable aqueous Zn metal batteries(ZMBs).Herein,we present a strategy for achieving a high-rate and long-cycle-life Zn metal anode by patterning Zn foil surfaces and endowing a Zn-Indium(Zn-In)interface in the microchannels.The accumulation of electrons in the microchannel and the zincophilicity of the Zn-In interface promote preferential heteroepitaxial Zn deposition in the microchannel region and enhance the tolerance of the electrode at high current densities.Meanwhile,electron aggregation accelerates the dissolution of non-(002)plane Zn atoms on the array surface,thereby directing the subsequent homoepitaxial Zn deposition on the array surface.Consequently,the planar dendrite-free Zn deposition and long-term cycling stability are achieved(5,050 h at 10.0 mA cm^(−2) and 27,000 cycles at 20.0 mA cm^(−2)).Furthermore,a Zn/I_(2) full cell assembled by pairing with such an anode can maintain good stability for 3,500 cycles at 5.0 C,demonstrating the application potential of the as-prepared ZnIn anode for high-performance aqueous ZMBs.

Layered barium vanadate nanobelts for high-performance aqueous zinc-ion batteries

Aqueous zinc-ion batteries(ZIBs)are deemed as the idea option for large-scale energy storage systems owing to many alluring merits including low manufacture cost,environmental friendliness,and high operations safety.However,to develop high-performance cathode is still significant for practical application of ZIBs.Herein,Ba_(0.23)V_(2)O_(5)·1.1H_(2)O(BaVO)nanobelts were fabricated as cathode materials of ZIBs by a typical hydrothermal synthesis method.Benefiting from the increased interlayer distance of 1.31 nm by Ba2+ and H2O pre-intercalated,the obtained BaVO nanobelts showed an excellent initial discharge capacity of 378 mAh·g^(-1) at 0.1 A·g^(-1),a great rate performance(e.g.,172 mAh·g^(-1) at 5 A·g^(-1)),and a superior capacity retention(93% after 2000 cycles at 5 A·g^(-1)).

Overview of the J-TEXT progress on RMP and disruption physics

The J-TEXT tokamak has been operated for ten years since its first plasma obtained at the end of 2007. The diagnostics development and main modulation systems, i.e. resonant magnetic perturbation （RMP） systems and massive gas injection （MGI） systems, will be introduced in this paper. Supported by these efforts, J-TEXT has contributed to research on several topics, especially on RMP physics and disruption mitigation. Both experimental and theoretical research show that RMP could lock, suppress or excite the tearing modes, depending on the RMP amplitude, frequency difference between RMP and rational surface rotation, and initial stabilities. The plasma rotation, particle transport and operation region are influenced by the RMP. Utilizing the MGI valves, disruptions have been mitigated with pure He, pure Ne, and a mixture of He and Ar （9：1）. A significant runaway current plateau could be generated with moderate amounts of Ar injection. The RMP has been shown to suppress the generation of runaway current during disruptions.

Overview of wall probes for erosion and deposition studies in the TEXTOR tokamak

An overview of diagnostic tools e test limiters and collector probes e used over the years for material migration studies in the TEXTOR tokamak is presented.Probe transfer systems are shown and their technical capabilities are described.This is accompanied by a brief pre-sentation of selected results and conclusions from the research on material erosion e deposition processes including tests of candidate materials(e.g.W,Mo,carbon-based composites)for plasma-facing components in controlled fusion devices.The use of tracer techniques and methods for analysis of materials retrieved from the tokamak are summarized.The impact of research on the reactor wall technology is addressed.

Study of Striated Heat Flux on EAST Divertor Plates Induced by LHW Using Infrared Camera

An upgraded infrared （IR） imaging system which provides a wide field of view （FOV） has been installed on the Experimental Advanced Superconducting Tokamak （EAST） to monitor the surface temperatures on plasma facing components. Modified magnetic topology induced by lower hybrid wave （LHW） can lead to the formation of striated heat flux （SHF} on divertor plates which can be clearly observed by IR camera. In this paper, LHW power modulation is applied to analyze the appearance of SHF. It is also demonstrated that deuterium （D） pellet injection and supersonic molecular beam injection （SMBI） can to some extent reduce the heat flux on the outer strike point （OSP）, but enhance the SHF on lower outer plates （LOP） of divertor. This may provide an optional approach to actively control the distribution of heat flux on diveror plates, which can protect materials from long duration high-heat flux.

Challenges for plasma-facing components in nuclear fusion

The interaction processes between the burning plasma and the first wall in a fusion reactor are diverse:the first wall will be exposed to extreme thermal loads of up to several tens of megawatts per square meter during quasistationary operation,combined with repeated intense thermal shocks(with energy densities of up to several megajoules per square meter and pulse durations on a millisecond time scale).In addition to these thermal loads,the wall will be subjected to bombardment by plasma ions and neutral particles(D,T,and He)and by energetic neutrons with energies up to 14 MeV.Hopefully,ITER will not only demonstrate that thermonuclear fusion of deuterium and tritiumis feasible inmagnetic confinement regimes;it will also act as a first test device for plasma-facingmaterials(PFMs)and plasma-facing components(PFCs)under realistic synergistic loading scenarios that cover all the above-mentioned load types.In the absence of an integrated test device,material tests are being performed primarily in specialized facilities that concentrate only on the most essential material properties.New multipurpose test facilities are now available that can also focus on more complex loading scenarios and thus help to minimize the risk of an unexpected material or component failure.Thermonuclear fusion-both with magnetic and with inertial confinement-is making great progress,and the goal of scientific break-even will be reached soon.However,to achieve that end,significant technical problems,particularly in the field of high-temperature and radiation-resistant materials,must be solved.With ITER,the first nuclear reactor that burns a deuterium–tritium plasma with a fusion power gain Q≥10 will start operation in the next decade.To guarantee safe operation of this rather sophisticated fusion device,new PFMs and PFCs that are qualified to withstand the harsh environments in such a tokamak reactor have been developed and are now entering the manufacturing stage.

Quantitative HRTEM and its application in the study of oxide materials

On the basis of a state-of-the-art aberration-corrected transmission electron microscope, the spherical aberration coefficient CSof the objective lens can be tuned to either a positive or a negative value. The use of a negative value of CS combined with an overfocus setting of the objective lens leads to the development of the negative CSimaging（NCSI） technique. Images obtained using the NCSI technique show superior contrast and signal intensity at atomic column positions than the corresponding positive CSimages, especially for weakly scattering oxygen columns that are in close proximity to strongly scattering cation columns in oxides. Based on the images obtained under the NCSI condition, quantification of the image contrast allows measurements of the atom positions with a precision of a few picometers and the local chemistry on atomic scale. In the present review, we discuss firstly the benefits of the NCSI technique in studies of oxide materials,and then show a procedure for quantitative analysis of the image based on the absolute value of contrast. In the last part,examples are given for the application of the quantitative high-resolution transmission electron microscopy（HRTEM） to the study of electric dipoles of oxide ferroelectrics and atomic-scale chemistry of interfaces.

热障涂层用高熔点多元钙钛矿的大气等离子喷涂

高熔点材料作为热障涂层材料,已成为备受关注的发展趋势。在高熔点材料中,人们开发了由Ba(Mg1/3Ta2/3)O3和La(Al1/4Mg1/2T1/4)O3组成的多元钙钛矿合成物,并采用大气等离子喷涂方法将其沉积在热障涂层体系中。本文对喷涂参数进行了优化,并记录了飞行粒子温度。对涂层的相组成、稳定性、形貌和孔隙率进行了检测,同时对热障涂层体系在高温的热循环寿命进行了研究。研究表明,起始物料的性能在大气等离子体喷涂中具有决定性的作用,并最终影响热障涂层的寿命。由粒子分析而得到的过程图表明了适宜的喷涂条件,这一喷涂条件可在钙钛矿的等离子喷涂过程中尽可能避免第二相的产生。

Probe manipulators for Wendelstein 7-X and their interaction with the magnetic topology

Probe manipulators are a versatile addition to typical plasma edge diagnostics.Equipped with material samples they allow for detailed investigation of plasma–wall interaction processes,such as material erosion,deposition or impurity transport pathways.When combined with electrical probes,a study of scrape-off layer and plasma edge density,temperature and flow profiles as well as magnetic topologies is possible.A mid-plane manipulator is already in operation on Wendelstein 7-X.A system in the divertor region is currently under development.In the present paper we discuss the critical issue of heat and power loads,power redistribution and experimental access to the complex magnetic topology of Wendelstein 7-X.All the aforementioned aspects are of relevance for the design and operation of a probe manipulator in a device like Wendelstein？7-X.A focus is put on the topological region that is accessible for the different coil current configurations at Wendelstein 7-X and the power load on the manipulator with respect to the resulting different magnetic configurations.Qualitative analysis of power loads on plasma-facing components is performed using a numerical tracer particle diffusion tool provided via the Wendelstein 7-X Webservices.

Physical properties and magnetic structure of a layered antiferromagnet PrPd0.82Bi2

We report the physical properties, crystalline and magnetic structures of singe crystals of a new layered antiferromagnetic(AFM) material PrPd0.82Bi2. The measurements of magnetic properties and heat capacity indicate an AFM phase transition at TN^7K. A large Sommerfeld coefficient of 329.23 m J·mol-1·K-2 is estimated based on the heat capacity data, implying a possible heavy-fermion behavior. The magnetic structure of this compound is investigated by a combined study of neutron powder and single-crystal diffraction. It is found that an A-type AFM structure with magnetic propagation wavevector k =(0 0 0) is formed below TN. The Pr3+ magnetic moment is aligned along the crystallographic c-axis with an ordered moment of 1.694(3) μBat 4K, which is smaller than the effective moment of the free Pr3+ ion of 3.58 μB.PrPd0.82Bi2 can be grown as large as 1 mm×1 cm in area with a layered shape, and is very easy to be cleaved, providing a unique opportunity to study the interplay between magnetism, possible heavy fermions, and superconductivity.

Influence of the X-point location on edge plasma transport in the J-TEXT tokamak with a high-field-side single-null divertor

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.

Effect of edge magnetic island on carbon screening in the J-TEXT tokamak

The effect of externally applied resonant magnetic perturbation(RMP)on carbon impurity behavior is investigated in the J-TEXT tokamak.It is found that the m/n=3/1 islands have an impurity screening effect,which becomes obvious while the edge magnetic island is generated via RMP field penetration.The impurity screening effect shows a dependence on the RMP phase with the field penetration,which is strongest if the O point of the magnetic island is near the low-field-side(LFS)limiter plate.By combining a methane injection experimental study and STRAHL impurity transport analysis,we found that the variation of the impurity transport dominates the impurity screening effect.The impurity diffusion at the inner plasma region(r/a<0.8)is enhanced with a significant increase in outward convection velocity at the edge region in the case of the magnetic island’s O point near the LFS limiter plate.The impurity transport coefficient varies by a much lower level for the case with the magnetic island’s X point near the LFS limiter plate.The interaction of the magnetic island and the LFS limiter plate is thought to contribute to the impurity transport variation with the dependence on the RMP phase.A possible reason is the interaction between the magnetic island and the LFS limiter.

硝酰氯的大气化学

硝酰氯(nitryl chloride,ClNO2)是大气中一种重要的气态污染物,对大气氧化性、一次污染物的降解和二次污染物的生成具有重要影响,并在全球氮循环和氯循环中扮演着不可忽视的角色。本文归纳了ClNO2的基本物理化学性质及其在大气中的生成和去除机制,并介绍了实验室研究和外场观测中ClNO2的主要测量方法。在此基础上,本文总结了过去十几年报道的ClNO2在实际大气中的时空分布特征,通过分析实验室模拟和外场观测的研究结果系统讨论了ClNO2非均相生成的机制、产率及其影响因素,探讨了ClNO2对氯自由基、大气氧化性以及臭氧和硝酸盐形成的影响。我们指出,ClNO2既耦合了气相化学和非均相化学,又耦合了夜间大气化学和日间光化学,在我国大气复合污染中可能起着非常重要的作用。最后,本文提出了ClNO2大气化学研究中尚待解决的关键科学问题,并简要讨论了该领域的未来发展方向。

Explicit diagnosis of the local ozone production rate and the ozone-NOx-VOC sensitivities

In the troposphere, ozone is a harmful gas compound to both human health and vegetation. Ozone is produced from the reaction of NO_x(@NO + NO_2) and VOCs(volatile organic compounds) with light. Due to the highly nonlinear relationships between ozone and its precursors, proper ozone mitigation relies on the knowledge of chemical mechanisms. In this study, an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain. The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign. First, the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp. The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h(1-h diurnal averaged). The contribution of individual peroxy radicals to ozone production was analyzed. In addition, the functional dependence of calculated P(O_3) reveals that ozone production was in a NO_x-limited regime during the campaign. Furthermore, the missing peroxy radical source will further extend NO_x-limited conditions to earlier in the day, making NO_xlimitation dominate more of a day than the current chemical model predicts. Finally, a multiple scenarios mode,also known as EKMA(empirical kinetic modeling approach), was used to simulate the response of P(O_3) to the imaginary change in precursor concentrations. We found that ozone production was in the NO_x-limited region. However, the use of NO_2 measured by the molybdenum converter and/or the absence of a peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production.

Plant Phenotyping:Past,Present,and Future

A plant develops the dynamic phenotypes from the interaction of the plant with the environment.Understanding these processes that span plant’s lifetime in a permanently changing environment is essential for the advancement of basic plant science and its translation into application including breeding and crop management.The plant research community was thus confronted with the need to accurately measure diverse traits of an increasingly large number of plants to help plants to adapt to resource-limiting environment and low-input agriculture.In this overview,we outline the development of plant phenotyping as a multidisciplinary field.We sketch the technological advancement that laid the foundation for the development of phenotyping centers and evaluate the upcoming challenges for further advancement of plant phenotyping specifically with respect to standardization of data acquisition and reusability.Finally,we describe the development of the plant phenotyping community as an essential step to integrate the community and effectively use the emerging synergies.

Canonical Workflows to Make Data FAlR

The FAIR principles have been accepted globally as guidelines for improving data-driven science and data management practices,yet the incentives for researchers to change their practices are presently weak.In addition,data-driven science has been slow to embrace workflow technology despite clear evidence of recurring practices.To overcome these challenges,the Canonical Workflow Frameworks for Research(CWFR)initiative suggests a large-scale introduction of self-documenting workflow scripts to automate recurring processes or fragments thereof.This standardised approach,with FAIR Digital Objects as anchors,will be a significant milestone in the transition to FAIR data without adding additional load onto the researchers who stand to benefit most from it.This paper describes the CWFR approach and the activities of the CWFR initiative over the course of the last year or so,highlights several projects that hold promise for the CWFR approaches,including Galaxy,Jupyter Notebook,and RO Crate,and concludes with an assessment of the state of the field and the challenges ahead.

HPC-oriented Canonical Workflows for Machine Learning Applications in Climate and Weather Prediction

Machine learning(ML)applications in weather and climate are gaining momentum as big data and the immense increase in High-performance computing(HPC)power are paving the way.Ensuring FAIR data and reproducible ML practices are significant challenges for Earth system researchers.Even though the FAIR principle is well known to many scientists,research communities are slow to adopt them.Canonical Workflow Framework for Research(CWFR)provides a platform to ensure the FAIRness and reproducibility of these practices without overwhelming researchers.This conceptual paper envisions a holistic CWFR approach towards ML applications in weather and climate,focusing on HPC and big data.Specifically,we discuss Fair Digital Object(FDO)and Research Object(RO)in the DeepRain project to achieve granular reproducibility.DeepRain is a project that aims to improve precipitation forecast in Germany by using ML.Our concept envisages the raster datacube to provide data harmonization and fast and scalable data access.We suggest the Juypter notebook as a single reproducible experiment.In addition,we envision JuypterHub as a scalable and distributed central platform that connects all these elements and the HPC resources to the researchers via an easy-to-use graphical interface.

Soil Organic Matter Composition in Coastal and Continental Date Palm Systems: Insights from Tunisian Oases

In Tunisia, the coastal Chenini oasis is characterized by a lush vegetation cover, whereas more inland continental oases(e.g., the Guettaya oasis) have a very scarce vegetation cover. For sustaining date palm production in these areas, organic fertilizers are applied,either spread on the soil surface(in Chenini) or buried under a sand layer(in Guettaya). We examined at a molecular level how these management techniques affect soil organic matter composition in oasis systems. A dominance of fresh plant input for Guettaya was indicated by solid-state 13C nuclear magnetic resonance spectroscopy signals, which was most pronounced in the uppermost soil close to palms. Evidence for more degraded organic matter was found in deeper soil near the palms, as well as in the soil distant from the palms. Amino sugar contents were low in the uppermost Guettaya soil near the palms. The overall microbial amino sugar residue contents were similar in range as those found in other dryland environments. With increasing distance from trees, the amino sugar contents declined in Guettaya, where the palms grow on bare soil, but this was not the case for Chenini, which has multi-layer vegetation cover under palms. In agreement with the results from previous dryland studies, the soil microbial community in both oasis systems was dominated by fungi in topsoil, and a shift toward bacteria-derived residues in subsurface soil. This might be due to higher variability of temperature and moisture in topsoil and/or lower degradability of fungal remains;however, further research is required to confirm this hypothesis.

我国华北地区冬季的N2O5摄取系数

通过迭代盒子模型定量了北京冬季污染过程的N2O5摄取系数γ(N2O5),发现其均值远低于其他地区冬季.颗粒物中硝酸盐强烈抑制N2O5非均相摄取,有机物也存在一定的抑制作用,但是颗粒物含水量是促进摄取的重要因素.华北冬季颗粒物中硝酸盐浓度高,含水量低是γ(N2O5)较低的关键因素.经典的γ(N2O5)参数化方案存在系统性高估,在改进的参数化方案中综合考虑了颗粒物粒径分布差异、含水量、硝酸盐和有机物镀膜的影响之后,参数化方案的预测能力得到有效提高.