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Mesoproterozoic biomineralization:Cyanobacterium-like filamentous siderite sheaths~1.4 Ga

Journal of Palaeogeography 2023年第3期12卷 384-400页

作者： Dong-Jie Tang xiao-Ying shi xi-Qiang Zhou Robert Riding State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences(Beijing)Beijing 100083China Institute of Earth Sciences China University of Geosciences(Beijing)Beijing 100083China School of Earth Sciences and Resources China University of Geosciences(Beijing)Beijing 100083China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Earth and Planetary Sciences University of TennesseeKnoxvilleTN 37996-1526USA

Biomineralization was a key development in a wide variety of organisms,yet its history prior to the Ediacaran remains poorly *** this paper,we describe~1420-1330 million year old microscopic tubes preserved as siderite(FeCO_(3)).In size and shape these tubes closely resemble cyanobacterial sheaths forming mineralized *** consider two competing explanations for their ***,the tubes and associated sediment were originally composed of Ca-carbonate that was subsequently replaced by *** this case,siderite mineralization was early,but post-mortem,as in early silicification,and preferentially preserved the more resilient ***,no relict calcite is ***,the Fe-carbonate mineralogy of the tubes and sediment is *** this case,photosynthetic oxygen may have precipitated Fe-oxyhydroxide that was promptly converted to siderite by dissimilatory iron reduction(DIR).Primary siderite mineralization of cyanobacteria has not been described *** explanations link photosynthetic processes to preferential sheath mineralization during the life of the cyanobacteria,as observed in present-day calcified *** process might include CO_(2)-concentrating mechanisms(CCMs)linked to relatively low levels of atmospheric CO_(2),consistent with empirical estimates of mid-Proterozoic CO_(2)levels based on paleosols and weathering *** either case,these cyanobacterium-like fossils preserved in siderite provide an early example of biomineralization and suggest the interactive in-fluences of both metabolic processes and ambient seawater chemistry.

关键词： xiamaling Formation Siderite Ferruginous Dissimilatory iron reduction(DIR) Iron formation(IF) CO_(2)-concentrating mechanism(CCM)

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Development of a nomogram for overall survival in patients with esophageal carcinoma:A prospective cohort study in China

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World Journal of Gastrointestinal Oncology 2025年第1期17卷 158-168页

作者： shi-shi Yu xi Zheng xiao-Sheng Li Qian-Jie Xu Wei Zhang Zhong-Li Liao Hai-Ke Lei Department of Gastroenterology Chongqing University Cancer HospitalChongqing 400030China Chongqing Cancer Multi-omics Big Data Application Engineering Research Center Chongqing University Cancer HospitalChongqing 400030China Department of Health Statistics School of Public HealthChongqing Medical UniversityChongqing 400016China

BACKGROUND Esophageal carcinoma(EC)presents a significant public health issue in China,with its prognosis impacted by myriad *** creation of a reliable prog-nostic model for the overall survival(OS)of EC patients promises to greatly advance the customization of treatment *** To create a more systematic and practical model that incorporates clinically significant indicators to support decision-making in clinical *** This study utilized data from a prospective longitudinal cohort of 3127 EC patients treated at Chongqing University Cancer Hospital between January 1,2018,and December 12,*** the least absolute shrinkage and selection operator regression alongside multivariate Cox regression analyses helped pinpoint pertinent variables for constructing the *** efficacy was assessed by concordance index(C-index),area under the receiver operating characteristic curve(AUC),calibration curves,and decision curve analysis(DCA).RESULTS Nine variables were determined to be significant predictors of OS in EC patients:Body mass index(BMI),Karnofsky performance status,TNM stage,surgery,radiotherapy,chemotherapy,immunotherapy,platelet-to-lymphocyte ratio,and albumin-to-globulin ratio(ALB/GLB).The model demonstrated a C-index of 0.715(95%CI:0.701-0.729)in the training cohort and 0.711(95%CI:0.689-0.732)in the validation *** the training cohort,AUCs for 1-year,3-year,and 5-year OS predictions were 0.773,0.787,and 0.750,respectively;in the validation cohort,they were 0.772,0.768,and 0.723,respectively,illustrating the model's *** curves and DCA verified the model's predictive accuracy and net *** A novel prognostic model for determining the OS of EC patients was successfully developed and validated to help clinicians in devising individualized treatment schemes for EC patients.

关键词： Esophageal carcinoma High-risk factors Prognosis Overall survival Prediction model

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Synthesis and reactivity of cobalt dinitrogen complex supported by nonsymmetrical pincer ligand

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Chinese Chemical Letters 2024年第7期35卷 259-263页

作者： Yuanjin Chen xianghui shi Dajiang Huang Junnian Wei Zhenfeng xi Beijing National Laboratory for Molecular Sciences(BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of ChemistryPeking UniversityBeijing 100871China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryShanghai 200032China

A nonsymmetrical PNN pincer ligand[6-(^(t)Bu_(2)PNH)C_(5)H_(4)N-2-(3-Mes)C_(3)H_(2)N_(2)]and its corresponding cobalt-N_(2)complex were synthesized and *** the stoichiometric reaction of the PNN ligand lithium salt with CoCl_(2),the complex 3,(PNN)CoCl,was ***,reduction of 3 with NaBHEt3under a dinitrogen atmosphere yielded complex 5,(PNN)Co(Ⅰ)(η^(1)-N_(2)).Single-crystal X-ray analysis,IR spectrum,and DFT calculations revealed that the dinitrogen in 5 was only weakly reduced by the cobalt *** reactions of 5 with carbon monoxide and 2,6-dimethylphenyl isocyanide gave carbonyl and isocyanide complexes 6 and 7 with the release of N_(2),***,these cobalt complexes,especially complex 5,demonstrated the capacity to convert dinitrogen to N(TMS)_(3)with moderate efficiency.

关键词： Dinitrogen fixation Dinitrogen transformation Nonsymmetrical pincer ligand Cobalt complex Catalytic silylamine formation

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MoSe_(2)/TiO_(2)heterostructure integrated in N-doped carbon nanosheets assembled porous core-shell microspheres for enhanced sodium storage

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Nano Research 2023年第7期16卷 9398-9406页

作者： Nianxiang shi Guangzeng Liu Baojuan xi Xuguang An Changhui Sun xinzheng Liu Shenglin xiong School of Chemistry and Chemistry Engineering Qilu Normal UniversityJinan 250200China School of Chemistry and Chemical Engineering and State Key Laboratory of Crystal MaterialsShandong UniversityJinan 250100China School of Mechanical Engineering Chengdu UniversityChengdu 610106China

Engineering the structure and composition of electrode materials is one of the essential means for achieving excellent electrochemical *** rational design of Na+host materials is still a massive challenge for sodium ion batteries(SIBs).Herein,MoSe_(2)/TiO_(2)heterostructure is integrated with N-doped carbon nanosheets to assemble into hierarchical flowerlike porous core-shell microspheres(MoSe_(2)/TiO_(2)@N-C),which is firstly reported by room-temperature stirring coupled with vulcanization *** cavity of the core-shell structure could provide enough storage space for Na+and alleviate the volume expansion during charge/discharge *** apertures between nanosheets provide a guarantee for the rapid penetration of electrolyte to enhance the utilization rate of electrode ***,building heterostructures by combining different phase structures can facilitate electron transfer and accelerate reaction *** from the synergistic contributions of structure and composition,MoSe_(2)/TiO_(2)@N-C as SIBs anode material shows better reversible capacities of 302.5 mAh·g^(-1)at 1 A·g^(-1)for 400 cycles and 217.4 mAh·g^(-1)at 4 A·g^(-1)for 900 ***,the reversible capacities can be restored entirely to the initial level after a high current density cycle.

关键词： MoSe_(2)/TiO_(2) flower-like hierarchical porous core-shell microspheres heterostructure sodium ion batteries

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Effect of shrub encroachment on leaf nutrient resorption in temperate wetlands in the Sanjiang Plain of Northeast China

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Ecological Processes 2022年第1期11卷 968-975页

作者： Le‑Lin Yu xin‑Hou Zhang Fu‑xi shi Rong Mao Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of ForestryJiangxi Agricultural UniversityNo.1101 Zhimin RoadNanchang 330045China Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China School of Environment Nanjing Normal UniversityNanjing 210046China

Background:Nutrient resorption is an important plant nutrient conservation strategy in ***,how shrub encroachment alters plant nutrient resorption processes is unclear in temperate ***,we collected green and senesced leaves of common sedge,grass,and shrub species in wetlands with high(50–65%)and low(20–35%)shrub covers in the Sanjiang Plain of Northeast China,and assessed the impact of shrub encroachment on leaf nitrogen(N)and phosphorus(P)resorption efficiency and proficiency at both plant growth form and community ***:The effects of shrub cover on leaf nutrient resorption efficiency and proficiency were identical among shrubs,grasses,and *** of plant growth forms,increased shrub cover reduced leaf N resorption efficiency and proficiency,but did not alter leaf P resorption efficiency and ***,the effect of shrub cover on leaf nutrient resorption efficiency and proficiency differed between plant growth form and community *** the community level,leaf N and P resorption efficiency decreased with increasing shrub cover because of increased dominance of shrubs with lower leaf nutrient resorption efficiency over grasses and ***,community‑level senesced leaf N and P concentrations increased with elevating shrub cover,showing a decline in leaf N and P resorption ***,the significant relationships between leaf nutrient resorption efficiency and proficiency indicate that shrub encroachment increased senesced leaf nutrient concentrations by decreasing nutrient resorption ***:These observations suggest that shrub encroachment reduces community‑level leaf nutrient resorp‑tion efficiency and proficiency and highlight that the effect of altered plant composition on leaf nutrient resorption should be assessed at the community level in temperate wetlands.

关键词： Biodiversity Freshwater marsh Nutrient conservation strategy Plant growth form Species composition

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Martensitic Transformation and Its Thermal Cycling Stability in Ni_(56)Mn_(21)Cu_4Ga_(19)High-Temperature Shape Memory Ribbon

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Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 243-248页

作者： xi-Li Lu De-xi Su Feng Chen Wei-Li Liu Yang-Guang shi Yun-xiang Tong Li Li Center for Biomedical Materials and Engineering Key Laboratory of Superlight Material and Surface TechnologyMinistry of Education Harbin Engineering University Department of Applied Physics Nanjing University of Aeronautics and Astronautics

The microstructure, martensitic transformation, and thermal cycling stability of Ni56Mn21Cu4Ga19 high-tem- perature shape memory ribbons subjected to different annealing conditions were investigated and compared with that of the bulk master alloy. It was shown that 7 phases precipitated in the bulk and the ribbons annealed for 5 h at 800 and 900 ℃, which lead to the same poor thermal cycling stability. However, the formation of 7 phase was inhibited in the ribbons annealed at 700 ℃ for 30 rnin and 5 h, which remarkably improved the thermal cycling stability and also shifted the martensitic transformation to a lower temperature with a drop of about 60 ℃ than other three samples.

关键词： Ni-Mn-Cu-Ga Annealing Melt spinning Martensitic transformation Shape memory alloy

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Determination of real-time oxygen transfer rate based on an electrochemical method

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Journal of Iron and Steel Research International 2022年第3期29卷 418-424页

作者： shi-sen Li Wan-ming Li De-jun Li Yu-lei Sun Jun-wei Dong xi-tao Yin xi-min Zang School of Materials and Metallurgy University of Science and Technology LiaoningAnshan114051LiaoningChina State Key Laboratory of Marine Engineering Anshan114051LiaoningChina Shenyang Huasheng Metallurgy Technology and Equipment Co. Ltd.Shenyang110819LiaoningChina School of Physics and Optoelectronic Engineering Ludong UniversityYantai264000ShandongChina

The interfacial oxygen transfer rate is one of the main factors to control the composition of *** commonly employed method of studying the interfacial oxygen transfer rate is the chemical composition analysis;however,it is difficult to be studied in ***,a new method of measuring the oxygen transfer rate at the gas-slag and slag-metal interfaces was reported based on electrochemical *** interfacial oxygen transfer rate in the smelting process of Inconel 718 superalloy was investigated at 1723,1773,1823,and 1873 *** experimental results show that the electrochemical method can measure the real-time oxygen content;hence,this method is promising in controlling the oxygen content in *** the temperature increased,both the equilibrium oxygen content and the rate of oxygen absorption increased significantly,and the increase was the most obvious when the temperature was 1873 *** possible reason is that the increase in temperature weakens the mass transfer resistance of the electric double layer at the interface,thus accelerating the oxygen transfer rate.

关键词： In situ measurement Charge Electrochemical method Temperature Oxygen transfer rate Equilibrium oxygen content

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Vibrational Spectrum of Methane in an Algebraic Model

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Chinese Physics Letters 1998年第4期15卷 260-262页

作者： HOU xi-wen DONG shi-hai MA Zhong-qi Institute of High Energy Physics Chinese Academy of SciencesBeijing 100039 Department of Physics University of Three GorgesYichang 443000

A U(2)algebraic model is used to explain the stretching and bending vibrational spectrum of methane,where the interactions between the stretching and the bending modes are taken into *** model provides good fits to the experimental vibrational eigenvalues with the smaller standard deviations of 9.57 and 9.08 cm^(-1) than those in other published algebraic models.

关键词： algebraic vibrational bending

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Thermoelectric properties of heavily Co-dopedβ-FeSi_(2)

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Journal of Materials Science & Technology 2024年第20期187卷 248-257页

作者： Jun Cheng Lu Gan c Jiawei Zhang Jinyang xi Lili xi Jiong Yang Tingting Deng Pengfei Qiu Xun shi Lidong Chen State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Materials Genome Institute Shanghai UniversityShanghai 200444China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China

Element doping is a widely employed strategy to enhance the thermoelectric(TE)properties of various materials.β-FeSi_(2)is a promising low-cost high-temperature TE material with exceptional thermal stabil-ity;however,the doping limit ofβ-FeSi_(2)is usually very low,which limits the tunability of electrical and thermal ***,a high doping content of 0.16 inβ-FeSi_(2)has been achieved by the introduc-tion of iridium(Ir),leading to the highest reported figure of merit(zT)of 0.6 inβ-FeSi_(2).Motivated by the successful heavy doping with Ir,this work aims to explore element heavy doping inβ-FeSi_(2)with cobalt(Co),a cheaper,more readily available dopant with a smaller atomic radius and closer electronegativity to iron(Fe).In this study,we successfully obtained a record-high doping content of 0.24 in Co-dopedβ-FeSi_(2)through a prolonged annealing *** the absence of a substantial enhancement in the zT of Co-dopedβ-FeSi_(2)at high doping levels,with a maximum zT of 0.3 at 900 K in Fe_(0.92)Co_(0.08)Si_(2),we observed a transition in the carrier transport mechanism as a function of Co doping content,attributed to changes in the band *** a low Co doping content(x≤0.12),Fe1-x Cox Si_(2)demonstrates dominant carrier transport via impurity levels within the band gap,exhibiting hopping *** the Co dop-ing content increases(x>0.16),the impurity levels overlap and form an impurity band,and the carrier transport turns into the impurity band *** observed band conduction behavior of Fe1-x Cox Si_(2)(x>0.16)mirrors that of Ir-dopedβ-FeSi_(2),but Fe1-x Cox Si_(2)shows much lower mobility,which can be at-tributed to the localized feature of the impurity band introduced by the Co ***,this study provides insights into the heavy Co doping and its influence on the TE properties and carrier conduction mechanisms inβ-FeSi_(2),helpful for the further development of this TE system.

关键词： β-FeSi_(2) Heavy doping Hopping Band conduction

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Effects　of　strength　matching　and　crack　depth　on　the　fracture　parameters　for　welded　joints

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China Welding 1994年第1期3卷 35-44页

作者： Tang Wei and shi Yaowu (xi’an Jiaotong University)

Fracture parameters of welded joints with different strength matching and crack depth in weld metal are investigated by using the methods of elastoplastic finite element analysis and three point bend specimen test. The results show that for shallow crack, the plastic zone turns large in loading process, and the fracture toughness turns high. The extent of the plastic zone of overmatched joint is larger than that of undermatched joint because it will extends to parent metal from the weld metal in loading process for the same CTOD value. The plastic zone of undermatched joint is restricted within the weld, and the size of that is small. Overmatched joint shows the fracture behaviour of shallow crack may more easily than the undermatched joint, while the two sorts of joint specimens have the same crack depth. Therefore, the fracture-resistant capability of overmatched weld is better than that of undermatched weld. when the toughness of weld metals is similar for both overmatched and undermatched joints.

关键词： welded joint fracture parameter plastic zone crack depth strength matching

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