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Spin effect on redox acceleration and regioselectivity in Fe-catalyzed alkyne hydrosilylation

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National Science Review 2024年第2期11卷 155-167页

作者： Peng he Meng-Yang Hu Jin-Hong Li Tian-Zhang Qiao Yi-lin Lu Shou-Fei Zhu Frontiers Science Center for New Organic Matter State Key Laboratory and Institute of Elemento-Organic Chemistry Nankai University

Iron catalysts are ideal transition metal catalysts because of the Earths abundant, cheap, biocompatible features of iron salts. Iron catalysts often have unique open-shell structures that easily undergo spin crossover in chemical transformations, a feature rarely found in noble metal catalysts. Unfortunately, little is known currently about how the open-shell structure and spin crossover affect the reactivity and selectivity of iron catalysts, which makes the development of iron catalysts a low efficient trial-and-error program. In this paper, a combination of experiments and theoretical calculations revealed that the iron-catalyzed hydrosilylation of alkynes is typical spin-crossover catalysis. Deep insight into the electronic structures of a set of well-defined open-shell active formal Fe(0) catalysts revealed that the spin-delocalization between the iron center and the 1,10-phenanthroline ligand effectively regulates the iron center's spin and oxidation state to meet the opposite electrostatic requirements of oxidative addition and reductive elimination, respectively,and the spin crossover is essential for this electron transfer process. The triplet transition state was essential for achieving high regioselectivity through tuning the nonbonding interactions. These findings provide an important reference for understanding the effect of catalyst spin state on reaction. It is inspiring for the development of iron catalysts and other Earth-abundant metal catalysts, especially from the point of view of ligand development.

关键词： spin effect spin-delocalization spin crossover iron-catalysis alkyne hydrosilylation

Establishing and clinically validating a machine learning model for predicting unplanned reoperation risk in colorectal cancer

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World Journal of Gastroenterology 2024年第23期30卷 2991-3004页

作者： Li-Qun Cai da-Qing Yang Rong-Jian Wang he Huang Yi-Xiong Shi Department of Colorectal and Anal Surgery Whenzhou Central HospitalWenzhou 325000Zhejiang ProvinceChina Department of Colorectal and Anorectal Surgery The First Affiliated Hospital of Wenzhou Medical UniversityWenzhou 325000Zhejiang ProvinceChina

BACKGROUND Colorectal cancer significantly impacts global health,with unplanned reoperations post-surgery being key determinants of patient *** predictive models for these reoperations lack precision in integrating complex clinical *** To develop and validate a machine learning model for predicting unplanned reoperation risk in colorectal cancer *** data of patients treated for colorectal cancer(n=2044)at the First Affiliated Hospital of Wenzhou Medical University and Wenzhou Central Hospital from March 2020 to March 2022 were retrospectively *** were divided into an experimental group(n=60)and a control group(n=1984)according to unplanned reoperation *** were also divided into a training group and a validation group(7:3 ratio).We used three different machine learning methods to screen characteristic variables.A nomogram was created based on multifactor logistic regression,and the model performance was assessed using receiver operating characteristic curve,calibration curve,Hosmer-Lemeshow test,and decision curve *** risk scores of the two groups were calculated and compared to validate the *** More patients in the experimental group were≥60 years old,male,and had a history of hypertension,laparotomy,and hypoproteinemia,compared to the control *** logistic regression analysis confirmed the following as independent risk factors for unplanned reoperation(Phesiologists *** operating characteristic curve analysis showed that the model had good discrimination and clinical *** This study used a machine learning approach to build a model that accurately predicts the risk of postoperative unplanned reoperation in patients with colorectal cancer,which can improve tr

关键词： Colorectal cancer Postoperative unplanned reoperation Unplanned reoperation Clinical validation Nomogram Machine learning models

Relative position of seeds driven the seedling growth are mediated by root-leaf traits

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Journal of Plant Ecology 2024年第2期17卷 24-35页

作者： Jing Zhu Xue-lin Wang Xing Jin Lan Jiang Hong-Yu lin Yang Hu Jin-Fu Liu Zhong-Sheng he College of Forestry Fujian Agriculture and Forestry UniversityFuzhou 350002China Key Laboratory of Fujian Universities for Ecology and Resource Statistics Fujian Agriculture and Forestry UniversityFuzhou 350002China Zhenjiang Natural Resources and Planning Bureau Economic and Technological Development Zone Branch Zhenjiang 212132China

Variations in plant traits are indicative of plant adaptations to forest environments,and studying their relationships with tree growth provides valuable insights into forest *** spatial arrangement of plant seeds within the forest litter or soil critically infuences the variations of root-leaf traits,thereby affecting the adaptive strategies of emerging ***,our current understanding of the impacts of individual root-leaf traits on seedling growth in different relative position,and whether these traits together affect growth,remains *** study focuses on the dominant tree species,Castanopsis kawakamii,within the Sanming *** Nature Reserve of *** present experiment aimed to examine the variations in root-leaf traits of seedling,focus on the relative positions of seeds within different layers:beneath or above the litter layer,or within the bare soil layer(without litter).Our fndings provided evidence supporting a coordinated relationship between root and leaf traits,wherein leaf traits varied in conjunction with root traits in the relative positions of ***,we observed that seedlings exhibited higher values for specifc leaf area and average root diameter,while displaying lower root tissue *** mixed model explained 86.1%of the variation in root-leaf traits,surpassing the variation explained by the relative ***,soil nitrogen acted as a mediator,regulating the relationship between seedling growth and root-leaf traits,specifcally leaf dry matter content and root tissue ***,future studies should consider artifcially manipulating tree species diversity based on root-leaf traits characteristics to promote forest recovery.

关键词： relative growth rate coordination leaf traits root traits soil nitrogen content seed relative positions

Accelerating lithium-sulfur battery reaction kinetics and inducing 3D deposition of Li_(2)S using interactions between Fe_(3)Se_(4)and lithium polysulfides

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Journal of Energy Chemistry 2024年第8期95卷 540-553,I0012页

作者： Yihan lin Liheng Li Longjie Tan Yongliang Li Xiangzhong Ren Peixin Zhang Chuanxin he lingna Sun College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060GuangdongChina

Although lithium-sulfur batteries(LSBs)exhibit high theoretical energy density,their practical application is hindered by poor conductivity of the sulfur cathode,the shuttle effect,and the irreversible deposition of Li_(2)*** address these issues,a novel composite,using electrospinning technology,consisting of Fe_(3)Se_(4)and porous nitrogen-doped carbon nanofibers was designed for the interlayer of *** porous carbon nanofiber structure facilitates the transport of ions and electrons,while the Fe_(3)Se_(4)material adsorbs lithium polysulfides(LiPSs)and accelerates its catalytic conversion ***,the Fe_(3)Se_(4)material interacts with soluble LiPSs to generate a new polysulfide intermediate,Li_(x)FeS_(y)complex,which changes the electrochemical reaction pathway and facilitates the three-dimensional deposition of Li_(2)S,enhancing the reversibility of *** designed LSB demonstrates a high specific capacity of1529.6 mA h g^(-1)in the first cycle at 0.2 *** rate performance is also excellent,maintaining an ultra-high specific capacity of 779.7 mA h g^(-1)at a high rate of 8 *** investigation explores the mechanism of the interaction between the interlayer and LiPSs,and provides a new strategy to regulate the reaction kinetics and Li_(2)S deposition in LSBs.

关键词： Lithium-sulfur batteries Polysulfide intermediates Li_(2)S electrodeposition Interlayers Electrostatic spinning Adsorption Catalysis

Physics of cavitation near particles

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Journal of Hydrodynamics 2024年第1期36卷 102-118页

作者： Jia-xin Yu Xiao-yu Wang Jun-wei Shen Jin-sen Hu Xiang-qing Zhang da-qing he Yu-ning Zhang Key Laboratory of Power Station Energy Transfer Conversion and System(Ministry of Education) School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

The combined effect of cavitation and silt abrasion presents a great challenge and threat to secure the operation and the efficiency of hydraulic machineries working in sediment-laden *** present paper critically reviews the current research progress on the interaction mechanisms of the bubbles and the ***,the analytical models including boundary treatment methods for predicting the jet dynamics of the bubble collapse near particles are ***,the bubble collapsing dynamics,jet dynamics and shock wave characteristics near particles are revealed both experimentally and ***,the bubble-particle-wall system is investigated with a focus on microjets.

关键词： Cavitation bubble particle jet shock wave

Transient Voltage Support Strategy of Grid-forming Medium Voltage Photovoltaic Converter in the LCC-HVDC System

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CSEE Journal of Power and Energy Systems 2024年第5期10卷 1849-1864页

作者： Hong Lu Xianyong Xiao Guangfu Tang Zhiyuan he Zhiguang lin Chong Gao Zixuan Zheng College of Electrical Engineering Sichuan UniversityChengdu 610065China State Key Lab of Advance Power Transmission Technology China Electric Power Research InstituteBeijing 100192China College of Electrical Engineering Sichuan UniversityChengdu 610065China.

The participation of photovoltaic(PV)plants in supporting the transient voltage caused by commutation failure in the line-commutated-converter-based high voltage direct current(LCC-HVDC)system is of great significance,as it can enhance the DC transmission ***,it is found that the gridfollowing(GFL)PV converters face the problem of mismatch between reactive power response and transient voltage characteristic when the voltage converts from low voltage to overvoltage,further aggravating the overvoltage ***,this article proposes a transient voltage support strategy based on the gridforming(GFM)medium voltage PV *** proposed strategy takes the advantage of the close equivalent electrical distance between the converter and grid,which can autonomously control the converter terminal voltage through GFM control with adaptive voltage droop *** simulation results show that the proposed strategy can ensure the output reactive power of the PV converter quickly matches the transient voltage characteristic at different stages,indicating that the proposed strategy can effectively support the transient voltage.

关键词： Commutation failure grid-forming(GFM) photovoltaic(PV)converter reactive power response transient voltage

Controlling hydrogenation of C=C and C=O bonds in cinnamaldehyde using Pt_(1)/Ni and Pt_(1)/Co single-atom alloy catalysts

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Rare Metals 2024年第6期43卷 2859-2868页

作者： Huan-Shi Lan Yi-da Yang Qing-Di Sun Hao Zhang Ying Zhang Qian he Ran Chen Guo-Yi Bai Xiao-Hui he Hong-Bing Ji School of Chemistry and Chemical Engineering Guangxi UniversityNanning 530004China Key Laboratory of Bioinorganicand Synthetic Chemistry of Ministry of Education Fine Chemical Industry Research InstituteSchool of ChemistryIGCMESun Yat-sen UniversityGuangzhou510275China UBFC CNRSENSMMFEMTO-ST Institute25030 Besancon CEDEXFrance College of Chemistry and Materials Science Hebei UniversityBaoding 071002China State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology Institute of Green Petroleum Processing and Light Hydrocarbon ConversionCollege of Chemical EngineeringZhejiang University of TechnologyHangzhou 310014China

Selective hydrogenation of C=C and C=O bonds in cinnamaldehyde(CAL)to produce desired products is a challenging task due to the complex conjugate system of the two unsaturated functional *** this study,a simple ball milling method is presented for synthesizing Pt-based single-atom alloy catalysts(SAAs)that can function as a control switch for the selective hydrogenation of CAL into highly valuable products.

关键词： alloy hydrogenation conjugate

Enhancing volatile fatty acids production from waste activated sludge: The role of pretreatment by N,N-bis(carboxymethyl)-L-glutamate (GLda)

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Environmental Science and Ecotechnology 2024年第5期21卷 149-157页

作者： Chang Liu lin Li linji Xu Tanglong Zhang Qiang he Xiaodong Xin Key Laboratory of the Three Gorges Reservoir Region's Eco-environment Ministry of EducationCollege of Environment and EcologyChongqing UniversityChongqing400045PR China Research Center for Eco-Environmental Engineering Dongguan University of TechnologyDongguan523808PR China

N,N-bis(carboxymethyl)-L-glutamate(GLda)is an eco-friendly chelating agent that effectively extracts multivalent metal ions from waste activated sludge(WAS)flocs,which could potentially alter their ***,the effect of GLda on the production of volatile fatty acids(VFAs)from WAS is not well ***,we demonstrate that pretreatment with GLda at a concentration of 200 mmol per kg VSS results in a significant increase of 142%in extractable extracellular polymeric substances and enhances the total VFAs yield by 64%compared to untreated *** reveal GLda's capability to mobilize organic-binding multivalent metal ions within sludge ***,post-pretreatment analyses showed the release of 69.1 mg L^(-1) of Ca and 109.8 mg L^(-1) of Fe ions from the flocs,leading to a more relaxed floc structure and a reduced apparent activation energy(10.6 versus 20 kJ mol1)for WAS *** dynamic simulations further demonstrate GLda's preferential binding to Fe3þand Ca2þover Mg2þ.Our study suggests that GLda pretreatment causes minimal disruption to reactor stability,thereby indicating the stability of microbial community *** has emerged as a viable pretreatment agent for enhancing volatile fatty acids production from waste activated sludge.

关键词： Anaerobic fermentation Pretreatment Resource recovery Multivalent metals Solubilization

Performance test of a half-feed peanut-cleaning picker suitable for clay hill areas in southern China

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International Journal of Agricultural and Biological Engineering 2024年第4期17卷 156-164页

作者： Shenying Wang Zhaoyan You dawei Sun Qiang Xiao Qiaojun Luo lin he Key Laboratory of Modern Agricultural Intelligent Equipment in South China Ministry of Agriculture and Rural AffairsGuangzhou 510630China Nanjing Institute of Agricultural Mechanization Ministry of Agriculture and Rural AffairsNanjing 210014China Key Laboratory of Agricultural Equipment for Hilly and Mountainous Areas in Southeastern China(Co-construction by Ministry and Province) Ministry of Agriculture and Rural AffairsHangzhou 310021China Inner Mongolia Autonomous Region Agricultural and Animal Husbandry Technology Promotion Center Hohhot 010000China

To solve the problems of excessive soil lumps,broken branches and seedlings in pods and difficulty in removing impurities in the harvested pods of peanuts in the hilly areas of southern China,which is due to the high soil viscosity and easy hardening,and to improve the soil removal effect of the peanut half-feed pod picker in hilly areas of China,this article designed a half-feed peanut-cleaning picker suitable for southern clay hilly areas and provided a detailed introduction to the overall structure,working principle,and adjustment methods of various operating *** field measurement experiments,the influencing factors and laws of soil removal performance indicators,such as the comprehensive soil removal rate and POD drop rate,were *** results showed that the comprehensive soil removal rate gradually increased with increasing soil patting frequency,soil patting amplitude,and picking roller speed,first increased and then decreased with increasing picking roller gap and gradually decreased with increasing soil patting plate gap and clamping conveyor chain *** comprehensive soil removal rate of the soil patting plate using the opposite patting method was greater than that of the swinging patting *** soil removal pod drop rate increased gradually with increasing soil patting frequency and amplitude and decreased with increasing soil patting plate gap and clamping conveyor chain *** soil removal pod drop rate of the soil patting plate using swing patting was lower than that using the opposite patting *** speed and gap of the picking roller had no effect on the soil removal pod drop *** frequency,amplitude,form,and gap of the soil patting plate had extremely significant impacts on the rate of decrease in the number of soil removal pod drop *** clamping conveyor chain speed had a significant impact,while the speed and gap of the picking roller had no significant *** influence of all factors on the comprehens

关键词： peanut southern clay hilly areas picker comprehensive soil removal rate soil removal pod drop rate