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Structure and electrochemical characteristics of Mg–Ti–Ni-based electrode alloys synthesized by mechanical milling

Journal of Iron and Steel Research International 2021年第10期28卷 1329-1340页

作者： Zhong-hui Hou Xin Wei Wei Zhang Ze-ming Yuan Hui Yong qi-lu ge Department of Functional Material Research Central Iron and Steel Research InstituteBeijing100081China Inner Mongolia University of Science and Technology Baotou014010Inner MongoliaChina

The vacuum induction melting was adopted to fabricating Mg_(50−x)Ti_(x)Ni_(45)Al_(3)Co_(2)(x=0,1,2,3,4 at.%)composites protected by the high-purity helium ***,the surface modification treatment of the as-cast alloys was carried out by mechanically coating *** amorphous and nanocrystalline Mg_(50−x)Ti_(x)Ni_(45)Al_(3)Co_(2)(x=0–4)+50 wt.%Ni hydrogen storing alloys as the negative materials in batteries were prepared through ball milling,and the influences of milling time and Ti dosage on the structure and electrochemical hydrogen storing behaviors of the corresponding samples were studied in *** electrochemical testing reveals that the as-milled alloys have excellent performances and can finish the electrochemical hydrogenation and dehydrogenation at indoor *** the first cycle without activation,the ball milling alloy obtains the maximum value of discharge *** capacity and cyclic steadiness of the composites conspicuously grow as Ti content and milling duration ***,the capacity retaining rate at 100th cycle and the discharge capacity of 30 h milling samples augment from 53%to 78%and from 435.2 to 567.2 mAh/g with changing Ti content from 0 to *** same performances of the alloy(x=4)are enhanced from 61%to 78%and from 379.9 to 567.2 mAh/g,respectively,with extending milling ***,high rate discharge ability,potential-step measurements,potentiodynamic polarization curves and electrochemical impedance spectrum manifest that the electrochemical kinetics properties can achieve significant amelioration as Ti content varies and milling duration is extended.

关键词： MgNi-based alloy Ti substitution of Mg Surface modification Mechanical milling Electrochemical performance

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Equivalent combined cycle modelling for three-heat-reservoir thermal Brownian heat pump with heat-transfer effect and its optimal performance

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Science China Technological Sciences 2025年

作者： Lingen CHEN Congzheng qi Yanlin ge Huijun FENG Hubei Provincial Key Laboratory of Chemical Equipment Intensification and Intrinsic Safety Wuhan Institute of Technology Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan Institute of Technology Institute of Thermal Science and Power Engineering Wuhan Institute of Technology School of Mechanical & Electrical Engineering Wuhan Institute of Technology

Because of the important role of the absorption heat pump in low-grade thermal energy utilization, this paper extends it to micro domain and performs a finite-time thermodynamic modelling for a three-heat-reservoir (THR) thermal Brownian heat pump with heat transfer effect by using an equivalent combined cycle method, which was applied for macro endoreversible THR heat pumps. The working principle and energy transformation rule are studied, and the coefficient of performance (COP) and heating load are derived. With a fixed overall thermal conductance of three heat exchangers, the maximal heating load is determined by optimizing thermal conductance distributions among three heat exchangers and barrier height, and the optimal working temperatures are also obtained. The impact of external heat transfer is elucidated to show the difference between this model and a non-equilibrium thermodynamic one. Results indicate that external heat transfer determines the energy transformation directly, and performance characteristics are closer to reality when external heat transfer is considered. The heating load has a maximal value about thermal conductance allocation ratios. About half the overall heat exchanger inventory needs to be assigned to the heat exchanger of the heating space for maximal heating load. When the cycle is with only heat transfer effect, the net particle numbers are zero, and the cycle fails to pump heat. The research results are expected to offer an idea for thermodynamic optimization and design of micro THR thermal Brownian heat pump devices.

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Distribution and mapping of temperate savanna in the sandy lands of eastern China

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Science China Earth Sciences 2025年第1期68卷 128-141页

作者： Xiaoya LI Feng WANG Tao DUAN Kaijie YANG Bin YANG Chunmei WANG Xin TIAN qi lu Institute of Ecological Conservation and Restoration Institute of Desertification Studies Chinese Academy of Forestry Institute of Desertification Institute of Desertification Studies Chinese Academy of Forestry Institute of Great Green Wall Satellite Application Centre for Ecology and Environment MEE Institute of Microelectronics Chinese Academy of Sciences Aerospace Information Research Institute Chinese Academy of Sciences Institute of Forest Resource Information Techniques Chinese Academy of Forestry

Savannas are distributed globally across various *** perform a significant socioeconomic role in regulating net primary productivity and the terrestrial carbon *** to the high spatial heterogeneity induced by the mixed distribution of trees and grasses,current global land-cover classification maps often classify savannas as forests or grasslands Temperate savannas in China cover a vast area,yet their spatial patterns and extent remain poorly *** study developed a novel remote sensing temperate savannas mapping method by integrating very high-resolution （VHR） unmanned aerial vehicle （UAV） and GF-6 satellite imagery based on the vegetation structure characteristics of temperate savannas using the FAO definition of *** and validation datasets were collected from VHR UAV imagery covering the main temperate savannah types with a ground area of 1818 *** fractional woody vegetation cover （FWVC） and fractional herbaceous vegetation cover （FHVC） in temperate savannas were estimated by integrating Classification and Regression Tree and Random Forest *** current distribution of temperate savannas in the Horqin and Otindag Sandy Lands of Eastern China was mapped to a unit area of 0.5 *** root-mean-square error （RMSE） values for the FWVC and FHVC models were 10.69% and 11.67%,and the R2values were 0.66 and 0.63,*** assessment indicated that the new temperate savanna map had high identification accuracy,with a Kappa coefficient of 0.70,overall accuracy of 0.88,and average accuracy of *** savannas in the sandy lands of eastern China were primarily distributed in the northern Horqin Sandy Land the central and eastern regions of the Otindag Sandy Land,and the transition zone from the southern slopes of the Greater Khingan Mountains to the plains,covering a total area of 3.27×10～6 *** main savannah types were elm,oak/maple,and shrub *** savannas were widely distributed in the Otindag Sandy

关键词： Temperate savanna UAV imagery GF-6 Fractional woody vegetation cover Fractional herbaceous vegetation cover Machine learning

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CO2-mediated bicarbonate conversion to concentrated formate in a CEM-based electrolyzer

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Journal of Energy Chemistry 2025年第1期100卷 605-611页

作者： Haocheng Xiong Donghuan Wu Haonan Li Andrew Li qikun Hu Siyao Song Bingjun Xu qi lu State Key Laboratory of Chemical Engineering Department of Chemical Engineering Tsinghua University College of Chemistry and Molecular Engineering Peking University Ordos Laboratory

Renewable energy-driven bicarbonate conversion to valuable chemicals presents an attractive strategy for mitigating CO2emissions,as bicarbonate can be efficiently generated from the capture of atmospheric CO2using alkaline solutions with reactive *** this work,we present a CO2-mediated bicarbonate conversion to pure formate using a cation exchange membrane-based electrolyzer with a 25 cm2electrode *** electrolysis achieved selectivities exceeding 75%for formate at a total current of 2.5 A,achieving formate concentrations up to 1.2 M and yields as high as 95%over extended *** techno-economic assessment confirmed the economic viability of the process,highlighting the potential for bicarbonate electrolysis as a sustainable method for producing valuable chemicals.

关键词： Electrocatalysis Techno-economic assessments Electrochemistry Flow electrolyzer

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Spatiotemporal characteristics and influencing factors of vegetation water use efficiency on the Tibetan Plateau in 2001–2020

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Journal of geographical Sciences 2025年第1期35卷 39-64页

作者： HE Chenyang WANG Yanjiao YAN Feng lu qi School of Ecological and Environmental Science East China Normal University Institute of Ecological Conservation and Restoration Chinese Academy of Forestry National Climate Center China Meteorological Administration

Water use efficiency （WUE）,as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ***,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain *** study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–*** indicated an annual mean WUE of 0.8088 gC/mm·m2across the plateau,with a spatial gradient reflecting decrease from the southeast toward the *** manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,***,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of *** factors accounted for 70.79%of the variability in *** leaf area index and temperature served as the major driving forces of WUE variation.

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g-C_(3)N_(4)nanosheets coupled with CoSe_(2)as co-catalyst for efficient photooxidation of xylose to xylonic acid

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Green Energy & Environment 2025年第1期10卷 231-238页

作者： qi Hao Yijun Liu Ren Zou ge Shi Shilian Yang Linxin Zhonga Wu Yang Xiao Chi Yunpeng Liu Shimelis Admassie Xinwen Peng State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou510641GuangdongChina Hainan Key Laboratory of Storage&Processing of Fruits and Vegetables Agricultural Products Processing Research InstituteChinese Academy of Tropical Agricultural SciencesZhanjiangGuangdong524001China Department of Chemistry and Centre for Advanced 2D Materials(CA2DM)National University of Singapore 3 Science Drive 3 Singapore117543Singapore School of Materials Science and Hydrogen Energy Foshan UniversityFoshan528231GuangdongChina Department of Chemistry Addis Ababa UniversityPO BOX 1176Addis AbabaEthiopia

Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added ***_(2)is a promising nonprecious,efficient cocatalyst for photooxidation,which can facilitate the separation of photogenerated electron–holes,increase the reaction rates,and enhance photocatalytic *** this work,we synthesized a stable and efficient photocatalysis system of CoSe_(2)/g-C_(3)N_(4)through attaching CoSe_(2)on g-C_(3)N_(4)sheets,with a yield of 50.12%for the selective photooxidation of xylose to xylonic *** light illumination,the photogenerated electrons were prone to migrating from g-C_(3)N_(4)to CoSe_(2)due to the higher work function of CoSe_(2),resulting in the accelerated separation of photogenerated electron–holes and the promoted ***,this study reveals the unique function of CoSe_(2),which can significantly promote oxygen adsorption,work as an electron sink and accelerate the generation of$O2-,thereby improving the selectivity toward xylonic acid over other *** work provides useful insights into the design of selective photocatalysts by engineering g-C_(3)N_(4)for biomass high-value utilization.

关键词： Biomass photooxidation Hemicelluloses Xylose g-C_(3)N_(4) Xylonic acid

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Cross-subcarrier precoder design for massive MIMO-OFDM downlink with symplectic optimization

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Science China(Information Sciences) 2025年

作者： Yu-Xuan ZHANG An-An lu Xiang-gen XIA Xi-qi GAO National Mobile Communications Research Laboratory Southeast University Purple Mountain Laboratories Department of Electrical and Computer Engineering University of Delaware

We propose a cross-subcarrier precoder design(CSPD) for massive multiple-input multiple-output(MIMO) orthogonal frequency division multiplexing(OFDM) downlink. This work aims to significantly improve the channel estimation and signal detection performance by enhancing the smoothness of the frequency domain effective channel. This is accomplished by designing a few vectors known as the transform domain precoding vectors(TDPVs), which are then transformed into the frequency domain to generate the precoders for a set of subcarriers. To combat the effect of channel aging, the TDPVs are optimized under imperfect channel state information(CSI). The optimal precoder structure is derived by maximizing an upper bound of the ergodic weighted sum-rate(WSR) and utilizing the a posteriori beam-based statistical channel model(BSCM). To avoid the large-dimensional matrix inversion, we propose an algorithm with symplectic optimization. Simulation results indicate that the proposed cross-subcarrier precoder design significantly outperforms conventional methods.

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Recent progress in the applications of presynaptic dopaminergic positron emission tomography imaging in parkinsonism

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Neural Regeneration Research 2025年第1期20卷 93-106页

作者： Yujie Yang Xinyi Li Jiaying lu Jingjie ge Mingjia Chen Ruixin Yao Mei Tian Jian Wang Fengtao Liu Chuantao Zuo Key Laboratory of Arrhythmias Ministry of EducationDepartment of Medical GeneticsShanghai East HospitalSchool of MedicineTongji UniversityShanghaiChina Department of Neurology National Research Center for Aging and MedicineNational Center for Neurological Disordersand State Key Laboratory of Medical NeurobiologyHuashan HospitalFudan UniversityShanghaiChina Department of Nuclear Medicine&PET Center National Center for Neurological Disordersand National Clinical Research Center for Aging and MedicineHuashan HospitalFudan UniversityShanghaiChina International Human Phenome Institutes(Shanghai) ShanghaiChina Human Phenome Institute Fudan UniversityShanghaiChina

Nowadays,presynaptic dopaminergic positron emission tomography,which assesses deficiencies in dopamine synthesis,storage,and transport,is widely utilized for early diagnosis and differential diagnosis of *** review provides a comprehensive summary of the latest developments in the application of presynaptic dopaminergic positron emission tomography imaging in disorders that manifest *** conducted a thorough literature search using reputable databases such as PubMed and Web of *** criteria involved identifying peer-reviewed articles published within the last 5 years,with emphasis on their relevance to clinical *** findings from these studies highlight that presynaptic dopaminergic positron emission tomography has demonstrated potential not only in diagnosing and differentiating various Parkinsonian conditions but also in assessing disease severity and predicting ***,when employed in conjunction with other imaging modalities and advanced analytical methods,presynaptic dopaminergic positron emission tomography has been validated as a reliable in vivo *** validation extends to screening and exploring potential neuropathological mechanisms associated with dopaminergic *** summary,the insights gained from interpreting these studies are crucial for enhancing the effectiveness of preclinical investigations and clinical trials,ultimately advancing toward the goals of neuroregeneration in parkinsonian disorders.

关键词： aromatic amino acid decarboxylase brain imaging dopamine transporter Parkinson’s disease parkinsonism positron emission tomography presynaptic dopaminergic function vesicle monoamine transporter type 2

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High-dose dexamethasone regulates microglial polarization via the GR/JAK1/STAT3 signaling pathway after traumatic brain injury

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Neural Regeneration Research 2025年第9期20卷 2611-2623页

作者： Mengshi Yang Miao Bai Yuan Zhuang Shenghua lu qianqian ge Hao Li Yu Deng Hongbin Wu Xiaojian Xu Fei Niu Xinlong Dong Bin Zhang Baiyun Liu Beijing Tiantan Hospital Capital Medical UniversityBeijingChina Department of Neurology The First Hospital of Tsinghua UniversityBeijingChina Department of Neurotrauma and Beijing Key Laboratory of Central Nervous System Injury Beijing Neurosurgical InstituteCapital Medical UniversityBeijingChina Department of Critical Care Medicine Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Center for Nerve Injury and Repair Beijing Institute of Brain DisordersChina National Clinical Research Center for Neurological DiseasesBeijingChina

Although microglial polarization and neuroinflammation are crucial cellular responses after traumatic brain injury,the fundamental regulatory and functional mechanisms remain insufficiently *** potent anti-inflammato ry agents,the use of glucoco rticoids in traumatic brain injury is still controversial,and their regulatory effects on microglial polarization are not yet *** the present study,we sought to determine whether exacerbation of traumatic brain injury caused by high-dose dexamethasone is related to its regulatory effects on microglial polarization and its mechanisms of *** vitro cultured BV2 cells and primary microglia and a controlled cortical impact mouse model were used to investigate the effects of dexamethasone on microglial ***,dexamethasone,RU486(a glucocorticoid receptor antagonist),and ruxolitinib(a Janus kinase 1 antagonist)were ***-sequencing data obtained from a C57BL/6 mouse model of traumatic brain injury were used to identify potential targets of *** Morris water maze,quantitative reverse transcription-polymerase chain reaction,western blotting,immunofluorescence and confocal microscopy analysis,and TUNEL,Nissl,and Golgi staining were performed to investigate our ***-throughput sequencing results showed that arginase 1,a marker of M2 microglia,was significantly downregulated in the dexamethasone group compared with the traumatic brain injury group at3 days post-traumatic brain *** dexamethasone inhibited M1 and M2 microglia,with a more pronounced inhibitory effect on M2microglia in vitro and in *** receptor plays an indispensable role in microglial polarization after dexamethasone treatment following traumatic brain ***,glucocorticoid receptor activation increased the number of apoptotic cells and neuronal death,and also decreased the density of dendritic spines.A possible downstream receptor signaling mechanism is th

关键词： apoptosis BV2 microglia dexamethasone glucocorticoid receptor glucocorticoids innate immune system microglial polarization neuroinflammation primary microglia traumatic brain injury

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Tunable non-Markovian and quantum coherence in the single-qubit dephasing noise channel

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Science China(Physics,Mechanics & Astronomy) 2025年

作者： Na-Na Zhang Chao-Yi Wu Xu Zhou qi-Yuan Liu Cheng-ge Liu Yong-Rui Guo Ren-Pu Li School of Optoelectronic Engineering Chongqing University of Posts and Telecommunications Department of Physics Applied Optics Beijing Area Major Laboratory Beijing Normal University

In this paper, we construct a single-qubit dephasing noise channel based on the nuclear magnetic resonance（NMR） system by employing the bath-engineering technology, and achieve the construction of the tunable non-Markovian environment in the dephasing noise channel. Our findings indicate that for the single-qubit system, the transition of system dynamics from Markovian to non-Markovian can be achieved by adjusting the base frequency of the noise power spectrum. However, the base frequency corresponding to this phase transition point is not fixed, and there is a certain relationship between it and the total evolution time of the single-qubit system. Through our research, we discovered a fundamental relationship: if the single-qubit system dynamics undergoe a transition from Markovian to non-Markovian at ω0within 0-2t ms, shortening the evolution time to 0-t ms results in an increase of the phase transition point to 2ω0. This insight offers crucial guidance for artificially crafting non-Markovian environments across arbitrary time scales in single-qubit systems, and it is not limited by the type of noise. Apart from system dynamics, quantum coherence is also a focal point of our research. We find that when the system dynamics exhibit non-Markovian behavior, the quantum coherence of the single-qubit system experiences revivals. Notably, the timing of these coherence revivals aligns with the instants of the non-Markovianity enhancement. Therefore, our research also serves as a pivotal foundation for the artificial manipulation and realization of quantum coherence revivals within diverse single-qubit systems.

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