Simulating the Escaping Atmosphere of GJ 436 b with Two-fluid Magnetohydrodynamic Models

Observations of transmission spectra reveal that hot Jupiters and Neptunes are likely to possess escaping atmospheres driven by stellar radiation.Numerous models predict that magnetic fields may exert significant influences on the atmospheres of hot planets.Generally,the escaping atmospheres are not entirely ionized,and magnetic fields only directly affect the escape of ionized components within them.Considering the chemical reactions between ionized components and neutral atoms,as well as collision processes,magnetic fields indirectly impact the escape of neutral atoms,thereby influencing the detection signals of planetary atmospheres in transmission spectra.In order to simulate this process,we developed a magnetohydrodynamic multi-fluid model based on MHD code PLUTO.As an initial exploration,we investigated the impact of magnetic fields on the decoupling of H^(+)and H in the escaping atmosphere of the hot Neptune GJ436b.Due to the strong resonant interactions between H and H^(+),the coupling between them is tight even if the magnetic field is strong.Of course,alternatively,our work also suggests that merging H and H^(+)into a single flow can be a reasonable assumption in MHD simulations of escaping atmospheres.However,our simulation results indicate that under the influence of magnetic fields,there are noticeable regional differences in the decoupling of H^(+)and H.With the increase of magnetic field strength,the degree of decoupling also increases.For heavier particles such as O,the decoupling between O and H^(+)is more pronounced.Our findings provide important insights for future studies on the decoupling processes of heavy atoms in the escaping atmospheres of hot Jupiters and hot Neptunes under the influence of magnetic fields.

Role of land-atmosphere coupling in persistent extreme climate events in eastern China in summer 2022

2022年暖季,中国东部地区遭受持续性高温,少雨和土壤干旱的复合极端事件.特征分析指出,在研究时段内,中国东部地区的气温,降水和土壤湿度呈现明显的季节内变化和南北差异。由1940-2022年的气候态可知,长江流域和东南地区的土壤含水充足,蒸散主要受限于陆面有效能量.然而,潜在机制研究指出,2022年土壤湿度对蒸散的限制作用在上述区域异常偏强,土壤湿度与气候要素之间的强反馈可能在2022年复合极端事件的演变和持续中发挥了关键作用。

ODS MA754合金传热界面接触热阻实验研究

鉴于ODS MA754合金传热界面的接触热阻参数对全固态堆芯空间反应堆系统的热量导出具有重要影响,研发和设计了高温高压接触热阻实验装置,测量了不同温度(20~800℃)、压力(0~80 MPa)、气体氛围(He、CO_(2))以及试件表面粗糙度(1.6、3.2μm)下ODS MA754合金传热界面的接触热阻,并基于测试获得的宽量程数据点,建立了ODS MA754合金的接触热阻数据库。实验结果表明:随着接触面温度和压力的升高,界面接触热阻降低,且热阻降低的速率逐渐减小;相较于表面粗糙度为1.6μm的试件,粗糙度为3.2μm试件表面的界面接触热阻明显偏大,实验得到的定量关系可为工程样件的加工粗糙度要求提供依据;He气氛下的接触热阻远小于CO_(2)气氛,在0.1 MPa、100℃工况下,He气氛接触热阻约为CO_(2)气氛接触热阻的1/4。该研究结果可为空间反应堆的热工设计提供数据参考。

肠道微生物与细菌性肺炎易感性的因果关系:双样本双向孟德尔随机化研究及cML-MA的应用

目的通过孟德尔随机化研究方法探究肠道菌群与细菌性肺炎易感性之间的因果关系。方法使用三种不同的孟德尔随机化分析方法,对211个肠道菌群类群与细菌性肺炎之间的关系进行211次双样本分析,并进行反向孟德尔随机化分析。以随机效应逆方差加权法(IVW)作为主要结果,并采用其他方法作为补充参考。结果柔膜菌纲(OR=1.14,95%CI 1.02~1.27,P=0.02)、放线菌科(OR=1.17,95%CI 1.02~1.35,P=0.03)、放线菌目(OR=1.17,95%CI 1.01~1.35,P=0.03)以及软壁菌门(OR=1.14,95%CI 1.02~1.27,P=0.02)的丰度升高与细菌性肺炎易感性的增加有关;消化球菌科(OR=0.88,95%CI 0.78~0.98,P=0.02)、直肠拟梭菌群(OR=0.85,95%CI 0.75~0.97,P=0.02)和鞘螺菌科UCG001(OR=0.90,95%CI 0.83~0.99,P=0.03)的丰度升高与细菌性肺炎的发病风险降低相关。一系列敏感性分析以及条件孟德尔随机化分析(cML-MA)的结果表示该研究结果可靠。反向孟德尔随机化未发现反向因果关联。结论肠道微生物的丰度升高与细菌性肺炎的易感性增加或降低相关,肠道菌群在细菌性肺炎发病机制中有重要作用,提供了潜在干预措施的新思路。

3D smart mA调控技术对不同BMI患者图像采集时间质量及辐射剂量的影响

目的:分析3D智能管电流(3D smart mA)调控技术对不同体质量指数(BMI)患者图像采集时间、质量及辐射剂量的影响。方法:择取的180例行胸部CT扫描患者选自西安交通大学第一附属医院2021年6月至2022年12月期间所收治,按照BMI将患者分为三组,A组(18.5 kg/m^(2)≤BMI≤23.9kg/m^(2),n=75)、B组(23.9kg/m^(2)0.05);两位医师对肺部不同层面图像质量(IQS)评分进行评价,Kappa一致性非常好(Kappa值=0.768、0.812、0.861);三组肺部不同层面IQS评分对比,差异无统计学意义(P>0.05);三组肺部不同层面CT对比,差异有统计学意义,且随着BMI增加而下降(P<0.05),三组肺部不同层面图像标准差(SD)值对比,差异无统计学意义(P>0.05);三组容积CT剂量指数(CTDIvol)对比,差异无统计学意义(P>0.05);A组DLP、ED均低于B、C组,B组DLP、ED低于C组(P<0.05)。结论:不同BMI患者应用3D smart mA调控技术,在保证图像质量的前提下,可有效降低辐射剂量。

基于AMASPGD算法的FSOC系统波前畸变校正及性能分析

为了抑制相干自由空间光通信系统中大气湍流引起光信号波前失真的不利影响,提出了一种基于聚合动量(AM)和自适应矩边界(AdaMod)优化器的增强型随机并行梯度下降(SPGD)算法。仿真结果表明,该优化算法可以显著提高收敛速度和鲁棒性,并有效降低波前畸变的峰谷值和均方根,从而更有效地抑制大气湍流对相干自由空间光通信(FSOC)系统混频效率和误码率的负面影响。

An integrated and efficient process for borax preparation and magnetite recovery from soda-ash roasted ludwigite ore under CO–CO_(2)–N_(2) atmosphere

To realize the comprehensive utilization of ludwigite ore,an integrated and efficient route for the boron and iron separation was proposed in this work,which via soda-ash roasting under CO–CO_(2)–N_(2) atmosphere followed by grind-leaching,magnetic separation,and CO_(2) carbonation.The effects of roasting temperature,roasting time,CO/(CO+CO_(2))composition,and Na_(2)CO_(3) dosage on the boron and iron separation indices were primarily investigated.Under the optimized conditions of the roasting temperature of 850℃,roasting time of 60 min,soda ash dosage of 20 wt%,and CO/(CO+CO_(2)) of 10 vol%,92%of boron was leached during wet grinding,and 88.6%of iron was recovered during the magnetic separation and magnetic concentrate with a total iron content of 61.51 wt%.Raman spectra and^(11)B NMR results indicated that boron exists asB(OH)_(4)^(-) in the leachate,from which high-purity borax pentahydrate could be prepared by CO_(2) carbonation.

烟草果胶和纤维素含量13C MultiCP/MAS NMR同时测量

果胶和纤维素是烟草细胞壁的重要组成成分,其含量对烟草品质与安全性产生重要影响。传统分析方法难以实现果胶和纤维素的同时定量。本文在优化核磁共振波谱序列条件的基础上,采用固体13C多重交叉极化/魔角旋转核磁共振波谱分析技术(13C MultiCP/MAS NMR)建立了烟草果胶和纤维素含量的同时测量新方法。方法以聚半乳糖醛酸和微晶纤维素为标准物质,以3-(三甲基甲硅烷基)丙酸-d4钠盐(TMSP)做为内标物质,分别建立内标法标准曲线,相关系数R2为0.999 0和0.998 2。果胶测量的检出限和定量限分别为0.38和1.28 mg·g^(–1),精密度(RSD,n=5)小于3.05%。纤维素测量的检出限和定量限为1.01和3.32 mg·g^(–1),精密度(RSD,n=5)小于2.74%。应用本方法测量烟梗、烟草薄片和烟叶等不同类型样品中的果胶和纤维素含量,并对比烟草行业标准方法的测量结果,果胶含量的相对误差在-0.95%至4.51%之间,纤维素含量的相对误差在0.77%至2.46%之间。表明13C MultiCP/MAS NMR方法快速,准确,适合批量样品的分析测量,为果胶和纤维素等细胞壁类大分子的同时定量分析提供重要技术支持。

抗奥合剂通过p38 MAPK/NF-κB信号通路和ACE2/Ang1-7/Mas轴缓解急性肺损伤研究

目的探讨抗奥合剂(KAHJ)治疗小鼠急性肺损伤(ALI)的作用及机制,为其可能作为缓解新型冠状病毒(COVID-19)感染后症状的药物提供依据。方法采用网络药理学方法预测KAHJ治疗ALI的主要活性成分、潜在靶点和相关信号通路。将C57BL/6J小鼠随机分为对照组、LPS组和LPS+KAHJ组。LPS+KAHJ组小鼠灌胃KAHJ(4.76 g·kg^(-1)·d^(-1),8.8 mL·kg^(-1)·d^(-1)),其余组小鼠灌胃生理盐水(8.8 mL·kg^(-1)·d^(-1))。14 d后,腹腔注射LPS(5 mg·kg^(-1))诱导ALI模型。收集小鼠血清和肺组织,通过组织病理学观察肺组织的病理变化。采用Western blot、qPCR、ELISA和IHC等方法评估KAHJ对ALI的改善作用。结果通过网络药理学筛选出疾病和药物共同的70个核心靶基因,并显示与多个信号通路密切相关,如MAPK、NF-κB、Apoptosis、COVID-19和肾素-血管紧张素系统(Ras)信号通路等。此外,通过实验验证发现KAHJ能改善小鼠ALI后的炎症和细胞凋亡,减少肺损伤和肺水肿,抑制肺纤维化。同时,KAHJ的作用机制与p38 MAPK和NF-κB的磷酸化以及ACE2/Ang1-7/Mas轴的调控也有着密切关系。结论KAHJ可能通过抑制p38 MAPK/NF-κB信号通路和调控ACE2/Ang1-7/Mas轴缓解ALI,为缓解COVID-19感染后症状提供了补充和替代药物。

Prediction model for corrosion rate of low-alloy steels under atmospheric conditions using machine learning algorithms

This work constructed a machine learning(ML)model to predict the atmospheric corrosion rate of low-alloy steels(LAS).The material properties of LAS,environmental factors,and exposure time were used as the input,while the corrosion rate as the output.6 dif-ferent ML algorithms were used to construct the proposed model.Through optimization and filtering,the eXtreme gradient boosting(XG-Boost)model exhibited good corrosion rate prediction accuracy.The features of material properties were then transformed into atomic and physical features using the proposed property transformation approach,and the dominant descriptors that affected the corrosion rate were filtered using the recursive feature elimination(RFE)as well as XGBoost methods.The established ML models exhibited better predic-tion performance and generalization ability via property transformation descriptors.In addition,the SHapley additive exPlanations(SHAP)method was applied to analyze the relationship between the descriptors and corrosion rate.The results showed that the property transformation model could effectively help with analyzing the corrosion behavior,thereby significantly improving the generalization ability of corrosion rate prediction models.

Current state of research on microplastics in the marine- atmosphere environment of the Arctic region

Microplastics,plastic particles smaller than 5 mm in size,are a growing source of environmental pollution.Microplastic pollution has been observed in situ in the remote Arctic,where it has been found in the land,sea,cryosphere,and atmosphere.This review summarizes the sample pretreatment techniques and analytical methods commonly used in microplastic research,as well as the pollution status of microplastics in the Arctic,their sources,and their effects on the environment.In the Arctic,the size distribution of microplastics is more inclined to small-scale aggregation,the shape of microplastics is mostly fibrous,with the proportion of fibers often accounting for more than 70%.There are marked differences among studies in terms of abundance and polymer composition,but polyester is generally dominant in seawater.Many microplastic particles are transported to the Arctic by ocean currents and rivers,but atmospheric transport and deposition are slowly being recognized as an important transport route.Sea ice is particularly important for the temporary storage,transport,and release of Arctic microplastics.The average storage of microplastics in sea ice was estimated to be approximately 6.1×108 items.Given their properties,microplastics can affect glacier melting,sea surface temperature changes,and even the carbon cycle.Urgent measures must be taken to improve research standards and overcome sampling difficulties in the Arctic region to achieve time continuity and large-scale distribution patterns of Arctic microplastics.

基于WRF-CMAQ的中国典型湖泊大气氮沉降特征

采用WRF-CMAQ模型模拟了2018年中国4个典型湖泊的不同形态氮(总氮TN、氧化态氮OXN、还原态氮REDN、硝酸盐氮NO-3-N、铵盐氮NH+4-N)的大气沉降通量。2018年青海湖、乌梁素海、东湖与太湖全年氮沉降通量分别为3.02、4.38、64.25、21.67 kgN/hm 2,大气氮沉降贡献的氮负荷分别占乌梁素海、东湖与太湖总氮负荷的0.9%、22.3%、11.3%,东湖与太湖受大气氮沉降的影响程度显著高于青海湖和乌梁素海,表明大气氮沉降对发达地区湖泊的影响更应受到关注。通过敏感性试验分析大气氮沉降量的影响因子,结果显示含氮污染物的沉降速率对湖泊氮沉降通量的影响不明显,而含氮污染物排放速率降低20%,可使4个湖泊总氮沉降通量下降11%~22%,表明相对氮沉降速率、氮排放变化是影响氮沉降量的主要因素。本研究为进一步厘清大气氮沉降对湖泊总氮负荷的作用并制定有效控制措施提供了科学依据。

MA-2吸收剂在国能锦界电厂15万t/a碳捕集装置上的应用研究

由中石化南京化工研究院开发的MA系列(用于低分压碳捕集)吸收剂已经在国内近10套万吨级碳捕集示范装置上成功运行。较为详细地讨论了该系列中MA-2吸收剂在国能锦界电厂15万t/a碳捕集装置上的运行情况,在设计进气量条件下,考察了气液比、捕集率等因素对再生能耗的影响并确定了较优值分别为34 m3/m3及95.2%,对应再生能耗最低为2.72 GJ/t。在上述条件下又逐步考察半富液级间冷却、富液分流、贫液MVR等节能工艺对再生能耗的影响并确定较优值,即当富液分流比为5%,级间冷却为40℃,MVR压差为50 kPa时,装置再生能耗最低仅为2.30 GJ/t。考察了不同工况下MA-2吸收剂的逃逸情况为31~59 mg/m3。

The Possibilities of Using the Minimax Method to Diagnose the State of the Atmosphere

The article is devoted to the discussion of the possibilities of approbation of one of the probabilistic methods of verification of evaluation works-the minimax method or the method of establishing the minimum risk of making erroneous diagnoses of the instability of the planetary boundary layer of air.Within the framework of this study,the task of probabilistic forecasting of diagnostic parameters and their combinations,leading in their totality to the formation of an unstable state of the planetary boundary layer of the atmosphere,was carried out.It is this state that,as shown by previous studies,a priori contribution to the development of a number of weather phenomena dangerous for society(squalls,hail,heavy rains,etc.).The results of applying the minimax method made it possible to identify a number of parameters,such as the intensity of circulation,the activity of the Earth’s magnetosphere,and the components of the geostrophic wind velocity,the combination of which led to the development of instability.In the future,it is possible to further expand the number of diagnosed parameters to identify more sensitive elements.In this sense,the minimax method,the usefulness of which is shown in this study,can be considered as one of the preparatory steps for the subsequent more detailed method for forecasting individual hazardous weather phenomena.

Reinforcement Learning-Based MAS Interception in Antagonistic Environments

Dear Editor, As a promising multi-agent systems(MASs) operation, autonomous interception has attracted more and more attentions in these years, where defenders prevent intruders from reaching destinations.So far, most of the relevant methods are applied in ideal environments without agent damages. As a remedy, this letter proposes a more realistic interception method for MASs suffered by damages.

Developing an atmospheric aging evaluation model of acrylic coatings:A semi-supervised machine learning algorithm

To study the atmospheric aging of acrylic coatings,a two-year aging exposure experiment was conducted in 13 representative climatic environments in China.An atmospheric aging evaluation model of acrylic coatings was developed based on aging data including11 environmental factors from 567 cities.A hybrid method of random forest and Spearman correlation analysis was used to reduce the redundancy and multicollinearity of the data set by dimensionality reduction.A semi-supervised collaborative trained regression model was developed with the environmental factors as input and the low-frequency impedance modulus values of the electrochemical impedance spectra of acrylic coatings in 3.5wt%NaCl solution as output.The model improves accuracy compared to supervised learning algorithms model(support vector machines model).The model provides a new method for the rapid evaluation of the aging performance of acrylic coatings,and may also serve as a reference to evaluate the aging performance of other organic coatings.

Assessment of molecular markers and marker-assisted selection for drought tolerance in barley(Hordeum vulgare L.)

This review updates the present status of the field of molecular markers and marker-assisted selection(MAS),using the example of drought tolerance in barley.The accuracy of selected quantitative trait loci(QTLs),candidate genes and suggested markers was assessed in the barley genome cv.Morex.Six common strategies are described for molecular marker development,candidate gene identification and verification,and their possible applications in MAS to improve the grain yield and yield components in barley under drought stress.These strategies are based on the following five principles:(1)Molecular markers are designated as genomic‘tags’,and their‘prediction’is strongly dependent on their distance from a candidate gene on genetic or physical maps;(2)plants react differently under favourable and stressful conditions or depending on their stage of development;(3)each candidate gene must be verified by confirming its expression in the relevant conditions,e.g.,drought;(4)the molecular marker identified must be validated for MAS for tolerance to drought stress and improved grain yield;and(5)the small number of molecular markers realized for MAS in breeding,from among the many studies targeting candidate genes,can be explained by the complex nature of drought stress,and multiple stress-responsive genes in each barley genotype that are expressed differentially depending on many other factors.

Agronomic Performance, Stability Analysis and Evaluation of Anthracnose Disease Resistance of Common Bean Lines Derived by Marker-Assisted Backcrossing in Uganda

The present study focused on evaluating the agronomic performance, stability, and anthracnose resistance of common bean lines derived through Marker-Assisted Backcrossing in Uganda. Eight marker-assisted selection (MAS) backcross-derived bush bean lines with red seed types, alongside two checks, were evaluated in a randomized complete block design replicated two times in five locations for three consecutive crop-growing seasons in 2021 and 2022. The study aimed to identify lines with both high stable yields and enhanced resistance to anthracnose disease for potential release and utilization in future bean varietal development in Uganda. Agronomic traits, including days to 50% flowering, days to 90% physiological maturity, seed yield, seed yield components, and anthracnose disease reaction under natural infestation were assessed. The response to anthracnose disease was further assessed using six isolates of Colletotrichum lindemuthianum representing six different races. Results indicated that the agronomic performances of the MAS backcross-derived bush bean lines were statistically comparable to the recurrent parent NABE14. Specifically, six lines exhibited statistically equal to or higher performance than NABE14 in terms of seed yield, total number of seeds and number of pods per plant. The combined analysis of variance for seed yield showed significant (p Co-42 and Co-5 anthracnose resistance genes in the derived line. In conclusion, UGKT-B157-4, identified as the best-performing and stable genotype, demonstrates promise for release and use in future bean varietal development in Uganda, offering a combination of high yields and enhanced anthracnose disease resistance. The study provides valuable insights into the potential of Marker-Assisted Backcrossing in improving common bean varieties in the region.

The corrosion characteristic and mechanism of Mg-5Y-1.5Nd-xZn-0.5Zr(x=0,2,4,6 wt.%)alloys in marine atmospheric environment

The microstructure and precipitated phases of as-cast Mg-5Y-1.5Nd-x Zn-0.5Zr(x=0,2,4,6 wt.%)alloys were investigated by optical microscopy,scanning electron microscopy,energy-dispersive spectrometry and X-ray Diffraction.The exposure corrosion experiment of these magnesium alloys was tested in South China Sea and KEXUE vessel atmospheric environment.The corrosion characteristic and mechanism of magnesium alloys of Mg-5Y-1.5Nd-x Zn-0.5Zr(x=0,2,4,6 wt.%)alloys were analyzed by weight loss rate,corrosion depth,corrosion products and corrosion morphologies.The electrochemical corrosion tests were also measured in the natural seawater.The comprehensive results showed that Mg-5Y-1.5Nd-4Zn-0.5Zr magnesium alloy existed the best corrosion resistance whether in the marine atmospheric environment and natural seawater environment.That depended on the microstructure,type and distribution of precipitated phases in Mg-5Y-1.5Nd-4Zn-0.5Zr magnesium alloy.Sufficient quantity anodic precipitated phases in the microstructure of Mg-5Y-1.5Nd-4Zn-0.5Zr alloy played the key role in the corrosion resistance.

Effect of CaO Impurity on Mullite Formation from SiO_(2) Gel and Al_(2)O_(3) Powders

To broaden the application of SiO_(2) sol-bonded castables,using micro-or nano-Al_(2)O_(3) powder and SiO_(2) gel powder as the main raw materials,the effects of CaO impurity on the formation of mullite by the reaction of Al_(2)O_(3) and SiO_(2) at different temperatures(1350,1400,1500,and 1600℃)in different atmospheres(oxidation atmosphere and reduction atmosphere)were studied.The results show that in the oxidizing atmosphere,the introduction of CaO can promote the formation of mullite.When the temperature increases from 1350℃to 1600℃,the amount of mullite formed gradually increases.In the reducing atmosphere,the introduction of CaO is not conducive to the formation of mullite,and the amount of mullite decreases with the increasing temperature.The smaller the particle size of Al_(2)O_(3),the more easily it reacts with SiO_(2) gel powder to form mullite.