中国卵巢组织冻存与移植后自然妊娠第2例报道

我国首个卵巢组织冻存库由首都医科大学附属北京妇产医院阮祥燕教授团队创建,该团队先后于2016年完成中国首例卵巢组织冻存与移植,2020年完成中国首例卵巢组织冻存与移植后妊娠,2021年报道中国首例卵巢组织冻存与移植后活产,至2024年已成功开展26例卵巢组织冻存与移植,移植患者全部恢复了卵巢功能并长期维持。本文报道再生障碍性贫血获得临床妊娠的患者,为中国第2例卵巢组织冻存与移植后妊娠病例。患者于外院经骨髓穿刺诊断为再生障碍性贫血(重型),2017年因药物、输血治疗效果欠佳,拟行异基因造血干细胞移植,因未婚未育,强烈要求生育力与卵巢功能保护,首都医科大学附属北京妇产医院对其进行综合评估后决定实施卵巢组织冻存,在全身麻醉下行腹腔镜下右侧卵巢切除术,手术顺利,取下的卵巢组织转运至首都医科大学附属北京妇产医院卵巢组织冻存库保存。造血干细胞移植后,患者于2018年行卵巢组织复苏与移植手术,手术顺利,无并发症发生。患者卵巢组织冻存与移植5年后结婚,卵巢功能维持良好,并于备孕4个月后自然妊娠,末次月经时间为2023年12月18日。

从模型到应用:基于生态系统服务权衡的乡村生态修复规划工具研究

在全球范围内的气候变化背景下,具有多种功能和服务价值的乡村生态空间成为当下国际生态规划研究与合作的关注热点之一。为实现乡村生态空间的精准管理与规划,中德双方围绕联合课题“生态系统服务概念在德国鲁尔与中国大都市区韧性发展模式下的绿色基础设施规划应用”进行了深入探索。在土地利用与土地覆盖类型的基础上,进一步识别了生物群落类型,并基于调节、供给、文化三大生态系统服务类型,选取了评估生态系统服务供需权衡的指标和对应权重,构建了乡村生态空间规划场景下的生态系统服务价值评测模型。以上海市水库村为例,运用该课题的评测模型,初步评估了典型乡村生态规划场景下的生态系统服务价值。最后,从应用尺度、研究范围以及操作流程三个方面总结了该评测模型的优化方向。

交联聚乙烯直流电树枝降压阶段的局部放电特性

电树枝是交联聚乙烯(XLPE)高压直流电缆的典型缺陷,有效检测电树枝对电缆绝缘状态评估至关重要。为此对含有电树枝的XLPE针-板绝缘试样进行直流局部放电实验,分析不同阶段下的局部放电特性以及电压参数对放电特性的影响。实验发现:含电树枝的试样在降压过程中会出现局部放电现象,不含电树枝的试样则不会放电;降压过程中的放电具有良好的重复性,对电树枝尺寸无明显影响,且放电脉冲极性与恒压阶段的相反。该实验现象表明利用降压阶段的局部放电检测,可为高压直流电缆电树枝的评估提供一种有益的尝试。此外,实验表明多次局部放电可能导致通道电导率增加,放电熄灭电压增大。不同电压参数下的降压阶段实验结果表明:更高的直流电压,合适的降压速率可以增加放电次数;针电极为负极性时平均放电量更高;恒压时长对放电特性没有显著影响。采用数值仿真分析了降压前后绝缘区域的电场分布,结果表明降压前期,泊松电场的衰减速率低于外施电场的衰减速率,使得针尖附近形成场强较高的反向电场,从而导致降压过程中的局部放电。

巨型机组下导轴承安装偏差对油膜特性的影响

水电机组在“碳达峰、碳中和”中发挥着非常重要的作用。下导轴承是水电机组轴系的重要组件,用于径向支撑和约束主轴,在水轮发电机运行过程中发挥重要作用。本文建立了考虑喷淋系统的下导轴承整体三维模型,对其油膜润滑性能以及安装偏差对轴承负荷的影响开展研究。分析发现,喷淋系统减少了油箱内的油搅,但瓦块间的润滑油流动是混乱的,损失主要是由瓦块之间的混乱流动所造成。对瓦块均沿径向偏移的偏差模型,随着瓦块沿径向向内偏移,其油膜压力与温度均逐渐升高;对瓦块均向一侧偏移的偏差模型,随着瓦块均向x轴正向偏移,压力与温度呈不对称分布,瓦面的最大压力与最高温度随偏差的增加而增加,不平衡径向力随偏差的增加而增加。因此,在下导轴承的安装过程中,必须注意瓦块均布圆周与主轴的同轴度。本研究对提高水轮发电机运行质量、降低运行成本和提高水电站效益具有重要意义,为保障百万千瓦水电机组的稳定安全运行提供参考依据。

Impact of T_(i)/T_(e )ratio on ion transport based on EAST H-mode plasmas

At the EAST tokamak, the ion temperature(T_(i)) is observed to be clamped around 1.25 keV in electron cyclotron resonance(ECR)-heated plasmas, even at core electron temperatures up to 10 keV(depending on the ECR heating power and the plasma density). This clamping results from the lack of direct ion heating and high levels of turbulence-driven transport. Turbulent transport analysis shows that trapped electron mode and electron temperature gradient-driven modes are the most unstable modes in the core of ECR-heated H-mode plasmas. Nevertheless, recently it was found that the T_(i)/T_(e)ratio can increase further with the fraction of the neutral beam injection(NBI) power, which leads to a higher core ion temperature(Ti0). In NBI heating-dominant H-mode plasmas, the ion temperature gradient-driven modes become the most unstable modes.Furthermore, a strong and broad internal transport barrier(ITB) can form at the plasma core in high-power NBI-heated H-mode plasmas when the T_(i)/T_(e)ratio approaches ~1, which results in steep core Teand Tiprofiles, as well as a peaked neprofile. Power balance analysis shows a weaker Teprofile stiffness after the formation of ITBs in the core plasma region, where Ticlamping is broken,and the core Tican increase further above 2 keV, which is 80% higher than the value of Ticlamping in ECR-heated plasmas. This finding proposes a possible solution to the problem of Ticlamping on EAST and demonstrates an advanced operational regime with the formation of a strong and broad ITB for future fusion plasmas dominated by electron heating.

Improved training framework in a neural network model for disruption prediction and its application on EXL-50

A neural network model with a classical annotation method has been used on the EXL-50tokamak to predict impending disruption.However,the results revealed issues of overfitting and overconfidence in predictions caused by inaccurate labeling.To mitigate these issues,an improved training framework has been proposed.In this approach,soft labels from previous training serve as teachers to supervise the further learning process;this has lead to a significant improvement in predictive model performance.Notably,this enhancement is primarily attributed to the coupling effect of the soft labels and correction mechanism.This improved training framework introduces an instance-specific label smoothing method,which reflects a more nuanced model assessment on the likelihood of a disruption.It presents a possible solution to effectively address the challenges associated with accurate labeling across different machines.

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.

CO_(2)capture costs of chemical looping combustion of biomass:A comparison of natural and synthetic oxygen carrier

Chemical looping combustion has the potential to be an efficient and low-cost technology capable of contributing to the reduction of the atmospheric concentration of CO_(2) in order to reach the 1.5/2°C goal and mitigate climate change.In this process,a metal oxide is used as oxygen carrier in a dual fluidized bed to generate clean CO_(2) via combustion of biomass.Most commonly,natural ores or synthetic materials are used as oxygen carrier whereas both must meet special requirements for the conversion of solid fuels.Synthetic oxygen carriers are characterized by higher reactivity at the expense of higher costs versus the lower-cost natural ores.To determine the viability of both possibilities,a techno-economic comparison of a synthetic material based on manganese,iron,and copper to the natural ore ilmenite was conducted.The synthetic oxygen carrier was characterized and tested in a pilot plant,where high combustion efficiencies up to 98.4%and carbon capture rates up to 98.5%were reached.The techno-economic assessment resulted in CO_(2) capture costs of 75 and 40€/tCO_(2) for the synthetic and natural ore route respectively,whereas a sensitivity analysis showed the high impact of production costs and attrition rates of the synthetic material.The synthetic oxygen carrier could break even with the natural ore in case of lower production costs and attrition rates,which could be reached by adapting the production process and recycling material.By comparison to state-of-the-art technologies,it is demonstrated that both routes are viable and the capture cost of CO_(2) could be reduced by implementing the chemical looping combustion technology.

杂原子掺杂电极用于全钒液流电池中的研究进展

液流电池因其本质安全、超长寿命等特性,是大规模储能的关键技术之一。电极材料作为全钒液流电池的核心部件,其与电解液的界面特性会对液流电池的性能产生重要影响。通过电极表面改性处理方法能够实现其在高电流密度下的电化学活性提升,而电极表面杂原子掺杂技术是目前的研究热点。本文归纳了以石墨毡为基体的杂原子掺杂机理及其研究进展,着重介绍了碳骨架的原位掺杂和电极表面的杂原子催化剂两种掺杂策略,并总结了两种掺杂策略的掺杂类型和性能差异。其中,依据杂原子的电负性和原子尺寸,阐述了电极材料原位掺杂的机理,讨论了杂原子对碳纤维电子结构的影响方式;根据碳基材料催化剂的种类,介绍了多孔炭材料、碳纳米管和石墨烯三种碳基催化剂的杂原子掺杂对电极材料电化学性能的影响规律。综合分析表明,通过电极表面的原子掺杂不仅可以增加电极反应的活性位点,促进活性离子的迁移,还可以改善其亲水性,增大电极与电解液接触的有效面积。基于此,提出了采用调控电极表面电荷分布、官能团种类、构建缺陷位点等方法有效增强电极材料的稳定性和电化学性能,并有望在实现高电流密度下电化学活性提高的同时获得较高的电导率。

Wear dependent virtual flow rate sensor for progressing cavity pumps with deformable stator

This contribution presents a novel wear dependent virtual flow rate sensor for single stage single lobe progressing cavity pumps. We study the wear-induced material loss of the pump components and the impact of this material loss on the volumetric efficiency. The results are combined with an established backflow model to implement a backflow calculation procedure that is adaptive to wear. We use a laboratory test setup with a highly abrasive fluid and operate a pump from new to worn condition to validate our approach. The obtained measurement data show that the presented virtual sensor is capable of calculating the flow rate of a pump being subject to wear during its regular operation.

VUV imaging of type-ⅠELM filamentary structures and their temporal characteristics on EAST

In the H-mode experiments conducted on the Experimental Advanced Superconducting Tokamak(EAST),fluctuations induced by the so-called edge localized modes(ELMs)are captured by a high-speed vacuum ultraviolet(VUV)imaging system.Clear field line-aligned filamentary structures are analyzed in this work.Ion transport induced by ELM filaments in the scrape-off layer(SOL)under different discharge conditions is analyzed by comparing the VUV signals with the divertor probe signals.It is found that convective transport along open field lines towards the divertor target dominates the parallel ion particle transport mechanism during ELMs.The toroidal mode number of the filamentary structure derived from the VUV images increases with the electron density pedestal height.The analysis of the toroidal distribution characteristics during ELM bursts reveals toroidal asymmetry.The influence of resonance magnetic perturbation(RMP)on the ELM size is also analyzed using VUV imaging data.When the phase difference of the coil changes periodically,the widths of the filaments change as well.Additionally,the temporal evolution of the ELMs on the VUV signals provides rise time and decay time for each single ELM event,and the results indicate a negative correlation trend between these two times.

The Soft X-ray Imager(SXI)on the SMILE Mission

The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in 2025.SXI is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE orbit.SXI is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s exosphere.SWCX provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field lines.The sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many hours.SXI is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States.

Application of three-dimensional MHD equilibrium calculation coupled with plasma response to island divertor experiments on J-TEXT

Three-dimensional(3D) equilibrium calculations, including the plasma rotation shielding effect to resonant magnetic perturbations(RMPs) produced by the island divertor(ID) coils, were carried out using the HINT and MARS-F codes on J-TEXT. Validation of 3D equilibrium calculations with experimental observations demonstrates that the shielding effect will prevent the penetration of the edge m/n = 3/1 mode component when the ID coil current is 4 k A, while change the size of magnetic islands once the current exceeds the penetration threshold. This indicates that equilibrium calculations including the plasma rotation shielding effect to RMPs can lead to better agreements with experimental observations compared to the vacuum approximation method. Additionally, the magnetic topology at the boundary undergoes changes,impacting the interaction between the plasma and the target plate. These results may be important in understanding RMP effects on edge transport and magnetohydrodynamic(MHD)instability control, as well as divertor heat and particle flux distribution control.

Mechanism of cross-level settlements and void accumulation of wide and conventional sleepers in railway ballast

The cross-level and twist irregularities are the most dangerous irregularity types that could cause wheel unloading with the risk of derailments and additional maintenance expenses.However,the mechanism of the irregularities initiation and development is unclear.The motivation of the present study was the previous experimental studies on the application of wide sleepers in the ballasted track.The long-term track geometry measurements with wide sleepers show an enormous reduction of the vertical longitudinal irregularities compared to the conventional track.However,wide sleepers had higher twist and cross-section level irregularities.The present paper aims to explain the phenomenon by discrete element method(DEM)modeling the development process of sleeper inhomogeneous support at cross-level depending on the sleeper form.The DEM simulations show that the maximal settlement intensity is up to 3.5 times lower for a wide sleeper in comparison with the conventional one.Nevertheless,the cross-level differential settlements are almost the same for both sleepers.The particle loading distribution after all loading cycles is concentrated on the smaller area,up to the half sleeper length,with fully unloaded zones under sleeper ends.Ballast flow limitation under the central part of the sleeper could improve the resilience of wide sleepers to the development of cross-level irregularities.The mechanism of initiation of the cross-level irregularity is proposed,which assumes the loss of sleeper support under sleeper ends.The further growth of inhomogeneous settlements along the sleeper is assumed as a result of the interaction of two processes:ballast flow due to dynamic impact during void closing and on the other side high pressure due to the concentration of the pressure under the middle part of the sleeper.The DEM simulation results support the assumption of the mechanism and agree with the experimental studies.

特高压直流输电换流阀设备数字化思考与实践

在能源和电网数字化转型要求大背景下,作为我国电网核心资产的特高压直流输电换流阀设备正面临全面数字化的挑战。文章首先在梳理目前特高压换流阀设备数字化现状及其数字化提升意义基础上,结合目前研究热点——数字孪生及相关技术,提出了换流阀设备数字化的总体目标及其数字孪生体架构和数据基础构建方法。然后,为了实现换流阀设备底层数据的高可靠低成本获取,文章介绍了在特高压换流阀设备上开展高可靠低功耗无线智能传感关键技术应用研究的成果和经验,主要包括低功耗无线传感网络系统开发、多物理量智能传感器研制、验证测试等方面。最后,对换流阀设备数字化的思考和实践进行总结,对未来换流阀设备数字化工作进行了展望。

Evaluation of an Autonomous Vehicle User Interface for Sensory Impaired Users

Autonomous vehicles (AVs) hold immense promises in revolutionizing transportation, and their potential benefits extend to individuals with impairments, particularly those with vision and hearing impairments. However, the accommodation of these individuals in AVs requires developing advanced user interfaces. This paper describes an explorative study of a multimodal user interface for autonomous vehicles, specifically developed for passengers with sensory (vision and/or hearing) impairments. In a driving simulator, 32 volunteers with simulated sensory impairments, were exposed to multiple drives in an autonomous vehicle while freely interacting with standard and inclusive variants of the infotainment and navigation system interface. The two user interfaces differed in graphical layout and voice messages, which adopted inclusive design principles for the inclusive variant. Questionnaires and structured interviews were conducted to collect participants’ impressions. The data analysis reports positive user experiences, but also identifies technical challenges. Verified guidelines are provided for further development of inclusive user interface solutions.

多燃料快速压缩膨胀机及动力系统应用分析

介绍了某型应用于多燃料燃烧可视化研究的快速压缩膨胀机。首先,介绍了快压机本体组成部件、总体参数和动力系统各模块可实现的进机边界条件、调节控制功能。其次,分别从快压机缸盖外形、缸盖强度校核、缸盖玻璃选型、缸盖专用垫片选型、起动系统主要组成部件、驱动电机选型、齿轮箱选型、起动计算等方面阐述了缸盖及起动系统设计要点。随后,对于动力系统中功能多样的进气配比系统和燃气系统分别从原理图、系统主要环节、设计指标、工作流程等方面进行说明。最后,分别进行了快压机倒拖测试、燃气系统功能测试、进气配比系统功能测试,实验结果表明快压机运行平稳、机械连接状态正常、燃气系统和进气配比系统均能满足燃烧可视化装置的试验需求。此快速压缩膨胀机应用分析为后续同类多燃料燃烧可视化装置设计及燃烧研究提供指导建议。

The effect of Laves phases and nano-precipitates on the electrochemical corrosion resistance of Mg-Al-Ca alloys under alkaline conditions

The electrochemical corrosion mechanisms of Mg alloys were extensively studied in previous investigations of different chemical com-positions,modified surface states and various electrolyte conditions.However,recent research focused on the active state of Mg dissolution,leading to unresolved effects of secondary phases adjacent to a stableα-solid solution passive layer.The present study investigates the fundamental electrochemical corrosion mechanisms of three different Laves phases with varying phase morphologies and phase fractions in the passive state of Mg-Al-Ca alloys.The microstructure was characterized by(transmission-)electron microscopy and synchrotron-based transmission X-ray microscopy.The electrochemical corrosion resistance was determined with a standard three-electrode setup and advanced in-situ flow cell measurements.A new electrochemical activity sequence(C15>C36>α-Mg>C14)was obtained,as a result of a stable passive layer formation on theα-solid solution.Furthermore,nm-scale Mg-rich precipitates were identified within the Laves phases,which tend to inhibit the corrosion kinetics.

Correction:Impact of Transition Metal Layer Vacancy on the Structure and Performance of P2 Type Layered Sodium Cathode Material

Following publication of the original article[1],the authors reported that the author Hun-Gi Jung should be affiliated as 3,4 and 5 instead of 4 and 5.The author’s name“A.-Yeon Kim”needed to be updated to“A-Yeon Kim”,removing the period.The correct author’s name and affiliation have been provided in this Correction.The original article[1]has been corrected.

Recycled graphite for more sustainable lithium-ion batteries

The demand for lithium-ion batteries(LIBs)is driven largely by their use in electric vehicles,which is projected to increase dramatically in the future.This great success,however,urgently calls for the efficient recycling of LIBs at the end of their life.Herein,we describe a froth flotation-based process to recycle graphite—the predominant active material for the negative electrode—from spent LIBs and investigate its reuse in newly assembled LIBs.It has been found that the structure and morphology of the recycled graphite are essentially unchanged compared to pristine commercial anode-grade graphite,and despite some minor impurities from the recycling process,the recycled graphite provides a remarkable reversible specific capacity of more than 350 mAh g^(−1).Even more importantly,newly assembled graphite‖NMC532 cells show excellent cycling stability with a capacity retention of 80%after 1000 cycles,that is,comparable to the performance of reference full cells comprising pristine commercial graphite.